| blob | 104d4dd6898b32e0533d4075f32e26240c939d8f |
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, 2010, 2011, 2012
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". */
48 /* The type of functions taking a tree, and some additional data, and
49 returning an int. */
52 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
53 instantiations have been deferred, either because their definitions
54 were not yet available, or because we were putting off doing the work. */
58 };
73 /* Live only within one (recursive) call to tsubst_expr. We use
74 this to pass the statement expression node from the STMT_EXPR
75 to the EXPR_STMT that is its result. */
78 /* A map from local variable declarations in the body of the template
79 presently being instantiated to the corresponding instantiated
80 local variables. */
83 /* True if we've recursed into fn_type_unification too many times. */
87 {
88 tree tmpl;
89 tree args;
90 tree spec;
94 htab_t decl_specializations;
97 htab_t type_specializations;
99 /* Contains canonical template parameter types. The vector is indexed by
100 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
101 TREE_LIST, whose TREE_VALUEs contain the canonical template
102 parameters of various types and levels. */
105 #define UNIFY_ALLOW_NONE 0
106 #define UNIFY_ALLOW_MORE_CV_QUAL 1
107 #define UNIFY_ALLOW_LESS_CV_QUAL 2
108 #define UNIFY_ALLOW_DERIVED 4
109 #define UNIFY_ALLOW_INTEGER 8
110 #define UNIFY_ALLOW_OUTER_LEVEL 16
111 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
112 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
115 tbr_incomplete_type,
116 tbr_ambiguous_baseclass,
117 tbr_success
118 };
139 tree);
201 location_t);
210 /* Make the current scope suitable for access checking when we are
211 processing T. T can be FUNCTION_DECL for instantiated function
212 template, VAR_DECL for static member variable, or TYPE_DECL for
213 alias template (needed by instantiate_decl). */
215 static void
217 {
226 else
230 {
231 saved_access_scope = tree_cons
234 }
235 }
237 /* Restore the scope set up by push_access_scope. T is the node we
238 are processing. */
240 static void
242 {
244 {
247 }
251 else
253 }
255 /* Do any processing required when DECL (a member template
256 declaration) is finished. Returns the TEMPLATE_DECL corresponding
257 to DECL, unless it is a specialization, in which case the DECL
258 itself is returned. */
260 tree
262 {
269 {
270 tree type;
278 {
282 }
284 }
288 {
290 {
293 }
294 else
296 }
297 else
301 }
303 /* Create a template info node. */
305 tree
307 {
312 }
314 /* Return the template info node corresponding to T, whatever T is. */
316 tree
318 {
336 }
338 /* Returns the template nesting level of the indicated class TYPE.
340 For example, in:
341 template <class T>
342 struct A
343 {
344 template <class U>
345 struct B {};
346 };
348 A<T>::B<U> has depth two, while A<T> has depth one.
349 Both A<T>::B<int> and A<int>::B<U> have depth one, if
350 they are instantiations, not specializations.
352 This function is guaranteed to return 0 if passed NULL_TREE so
353 that, for example, `template_class_depth (current_class_type)' is
354 always safe. */
356 int
358 {
365 {
371 }
374 }
376 /* Subroutine of maybe_begin_member_template_processing.
377 Returns true if processing DECL needs us to push template parms. */
379 static bool
381 {
387 }
389 /* Subroutine of maybe_begin_member_template_processing.
390 Push the template parms in PARMS, starting from LEVELS steps into the
391 chain, and ending at the beginning, since template parms are listed
392 innermost first. */
394 static void
396 {
404 current_template_parms
410 NULL);
412 {
421 {
428 {
429 /* Make a CONST_DECL as is done in process_template_parm.
430 It is ugly that we recreate this here; the original
431 version built in process_template_parm is no longer
432 available. */
442 }
447 }
448 }
449 }
451 /* Restore the template parameter context for a member template or
452 a friend template defined in a class definition. */
454 void
456 {
457 tree parms;
461 {
466 {
469 }
472 }
474 /* Remember how many levels of template parameters we pushed so that
475 we can pop them later. */
477 }
479 /* Undo the effects of maybe_begin_member_template_processing. */
481 void
483 {
492 {
496 }
497 }
499 /* Return a new template argument vector which contains all of ARGS,
500 but has as its innermost set of arguments the EXTRA_ARGS. */
502 static tree
504 {
505 tree new_args;
523 }
525 /* Like add_to_template_args, but only the outermost ARGS are added to
526 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
527 (EXTRA_ARGS) levels are added. This function is used to combine
528 the template arguments from a partial instantiation with the
529 template arguments used to attain the full instantiation from the
530 partial instantiation. */
532 static tree
534 {
535 tree new_args;
537 /* If there are more levels of EXTRA_ARGS than there are ARGS,
538 something very fishy is going on. */
541 /* If *all* the new arguments will be the EXTRA_ARGS, just return
542 them. */
546 /* For the moment, we make ARGS look like it contains fewer levels. */
551 /* Now, we restore ARGS to its full dimensions. */
555 }
557 /* Return the N levels of innermost template arguments from the ARGS. */
559 tree
561 {
562 tree new_args;
568 /* If N is 1, just return the innermost set of template arguments. */
572 /* If we're not removing anything, just return the arguments we were
573 given. */
579 /* Make a new set of arguments, not containing the outer arguments. */
586 }
588 /* The inverse of get_innermost_template_args: Return all but the innermost
589 EXTRA_LEVELS levels of template arguments from the ARGS. */
591 static tree
593 {
594 tree new_args;
600 /* If N is 1, just return the outermost set of template arguments. */
604 /* If we're not removing anything, just return the arguments we were
605 given. */
610 /* Make a new set of arguments, not containing the inner arguments. */
617 }
619 /* We've got a template header coming up; push to a new level for storing
620 the parms. */
622 void
624 {
625 /* We use a non-tag-transparent scope here, which causes pushtag to
626 put tags in this scope, rather than in the enclosing class or
627 namespace scope. This is the right thing, since we want
628 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
629 global template class, push_template_decl handles putting the
630 TEMPLATE_DECL into top-level scope. For a nested template class,
631 e.g.:
633 template <class T> struct S1 {
634 template <class T> struct S2 {};
635 };
637 pushtag contains special code to call pushdecl_with_scope on the
638 TEMPLATE_DECL for S2. */
643 }
645 /* This routine is called when a specialization is declared. If it is
646 invalid to declare a specialization here, an error is reported and
647 false is returned, otherwise this routine will return true. */
649 static bool
651 {
654 /* [temp.expl.spec]
656 An explicit specialization shall be declared in the namespace of
657 which the template is a member, or, for member templates, in the
658 namespace of which the enclosing class or enclosing class
659 template is a member. An explicit specialization of a member
660 function, member class or static data member of a class template
661 shall be declared in the namespace of which the class template
662 is a member. */
664 {
667 }
669 /* [temp.expl.spec]
671 In an explicit specialization declaration for a member of a class
672 template or a member template that appears in namespace scope,
673 the member template and some of its enclosing class templates may
674 remain unspecialized, except that the declaration shall not
675 explicitly specialize a class member template if its enclosing
676 class templates are not explicitly specialized as well. */
678 {
681 }
684 }
686 /* We've just seen template <>. */
688 bool
690 {
694 }
696 /* Called at then end of processing a declaration preceded by
697 template<>. */
699 void
701 {
704 }
706 /* Any template <>'s that we have seen thus far are not referring to a
707 function specialization. */
709 void
711 {
714 }
716 /* We've just seen a template header. If SPECIALIZATION is nonzero,
717 it was of the form template <>. */
719 static void
721 {
723 template_header_count++;
724 }
726 /* We're beginning an explicit instantiation. */
728 void
730 {
733 }
736 void
738 {
741 }
743 /* An explicit specialization or partial specialization of TMPL is being
744 declared. Check that the namespace in which the specialization is
745 occurring is permissible. Returns false iff it is invalid to
746 specialize TMPL in the current namespace. */
748 static bool
750 {
753 /* [tmpl.expl.spec]
755 An explicit specialization shall be declared in the namespace of
756 which the template is a member, or, for member templates, in the
757 namespace of which the enclosing class or enclosing class
758 template is a member. An explicit specialization of a member
759 function, member class or static data member of a class template
760 shall be declared in the namespace of which the class template is
761 a member. */
764 {
767 }
769 /* Same or super-using namespace. */
771 else
772 {
776 }
777 }
779 /* SPEC is an explicit instantiation. Check that it is valid to
780 perform this explicit instantiation in the current namespace. */
782 static void
784 {
785 tree ns;
787 /* DR 275: An explicit instantiation shall appear in an enclosing
788 namespace of its template. */
794 }
796 /* The TYPE is being declared. If it is a template type, that means it
797 is a partial specialization. Do appropriate error-checking. */
799 tree
801 {
802 tree context;
808 {
812 }
817 /* Consider non-class instantiations of alias templates as
818 well. */
823 {
824 /* This is for ordinary explicit specialization and partial
825 specialization of a template class such as:
827 template <> class C<int>;
829 or:
831 template <class T> class C<T*>;
833 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
838 {
842 {
846 }
847 }
853 {
857 }
858 }
864 {
865 /* This is for an explicit specialization of member class
866 template according to [temp.expl.spec/18]:
868 template <> template <class U> class C<int>::D;
870 The context `C<int>' must be an implicit instantiation.
871 Otherwise this is just a member class template declared
872 earlier like:
874 template <> class C<int> { template <class U> class D; };
875 template <> template <class U> class C<int>::D;
877 In the first case, `C<int>::D' is a specialization of `C<T>::D'
878 while in the second case, `C<int>::D' is a primary template
879 and `C<T>::D' may not exist. */
883 {
884 tree t;
889 {
892 }
894 /* Check for invalid specialization after instantiation:
896 template <> template <> class C<int>::D<int>;
897 template <> template <class U> class C<int>::D; */
901 {
904 {
905 /* We already have a full specialization of this partial
906 instantiation. Reassign it to the new member
907 specialization template. */
908 spec_entry elt;
925 }
927 /* But if we've had an implicit instantiation, that's a
928 problem ([temp.expl.spec]/6). */
931 }
933 /* Mark TYPE as a specialization. And as a result, we only
934 have one level of template argument for the innermost
935 class template. */
939 }
940 }
942 {
943 /* Someday C++0x may allow for enum template specialization. */
948 else
949 {
952 }
953 }
956 }
958 /* Returns nonzero if we can optimize the retrieval of specializations
959 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
960 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
964 {
967 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
968 parameter. */
970 /* The optimized lookup depends on the fact that the
971 template arguments for the member function template apply
972 purely to the containing class, which is not true if the
973 containing class is an explicit or partial
974 specialization. */
978 /* It is possible to have a template that is not a member
979 template and is not a member of a template class:
981 template <typename T>
982 struct S { friend A::f(); };
984 Here, the friend function is a template, but the context does
985 not have template information. The optimized lookup relies
986 on having ARGS be the template arguments for both the class
987 and the function template. */
989 }
991 /* Retrieve the specialization (in the sense of [temp.spec] - a
992 specialization is either an instantiation or an explicit
993 specialization) of TMPL for the given template ARGS. If there is
994 no such specialization, return NULL_TREE. The ARGS are a vector of
995 arguments, or a vector of vectors of arguments, in the case of
996 templates with more than one level of parameters.
998 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
999 then we search for a partial specialization matching ARGS. This
1000 parameter is ignored if TMPL is not a class template. */
1002 static tree
1004 {
1010 /* There should be as many levels of arguments as there are
1011 levels of parameters. */
1016 {
1017 tree class_template;
1018 tree class_specialization;
1020 tree fns;
1023 /* The template arguments actually apply to the containing
1024 class. Find the class specialization with those
1025 arguments. */
1027 class_specialization
1031 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1032 for the specialization. */
1036 /* Iterate through the methods with the indicated name, looking
1037 for the one that has an instance of TMPL. */
1040 {
1043 /* using-declarations can add base methods to the method vec,
1044 and we don't want those here. */
1047 }
1049 }
1050 else
1051 {
1053 spec_entry elt;
1054 htab_t specializations;
1062 else
1070 }
1073 }
1075 /* Like retrieve_specialization, but for local declarations. */
1077 static tree
1079 {
1087 }
1089 /* Returns nonzero iff DECL is a specialization of TMPL. */
1091 int
1093 {
1094 tree t;
1097 {
1103 }
1104 else
1105 {
1114 }
1117 }
1119 /* Returns nonzero iff DECL is a specialization of friend declaration
1120 FRIEND_DECL according to [temp.friend]. */
1122 bool
1124 {
1131 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1132 of a template class, we want to check if DECL is a specialization
1133 if this. */
1137 {
1138 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1141 }
1146 /* There is nothing to do if this is not a template friend. */
1153 /* [temp.friend/6]
1154 A member of a class template may be declared to be a friend of a
1155 non-template class. In this case, the corresponding member of
1156 every specialization of the class template is a friend of the
1157 class granting friendship.
1159 For example, given a template friend declaration
1161 template <class T> friend void A<T>::f();
1163 the member function below is considered a friend
1165 template <> struct A<int> {
1166 void f();
1167 };
1169 For this type of template friend, TEMPLATE_DEPTH below will be
1170 nonzero. To determine if DECL is a friend of FRIEND, we first
1171 check if the enclosing class is a specialization of another. */
1178 {
1179 /* Next, we check the members themselves. In order to handle
1180 a few tricky cases, such as when FRIEND_DECL's are
1182 template <class T> friend void A<T>::g(T t);
1183 template <class T> template <T t> friend void A<T>::h();
1185 and DECL's are
1187 void A<int>::g(int);
1188 template <int> void A<int>::h();
1190 we need to figure out ARGS, the template arguments from
1191 the context of DECL. This is required for template substitution
1192 of `T' in the function parameter of `g' and template parameter
1193 of `h' in the above examples. Here ARGS corresponds to `int'. */
1200 {
1202 {
1205 else
1207 current_depth++;
1208 }
1210 }
1213 {
1215 tree friend_type;
1216 tree decl_type;
1217 tree friend_args_type;
1218 tree decl_args_type;
1220 /* Make sure that both DECL and FRIEND_DECL are templates or
1221 non-templates. */
1227 {
1228 /* If both are templates, check template parameter list. */
1229 tree friend_parms
1234 friend_parms))
1238 }
1239 else
1247 /* Check if return types match. */
1251 /* Check if function parameter types match, ignoring the
1252 `this' parameter. */
1261 }
1262 else
1263 {
1264 /* DECL is a TYPE_DECL */
1268 /* Make sure that both DECL and FRIEND_DECL are templates or
1269 non-templates. */
1270 is_template
1277 {
1278 tree friend_parms;
1279 /* If both are templates, check the name of the two
1280 TEMPLATE_DECL's first because is_friend didn't. */
1285 /* Now check template parameter list. */
1286 friend_parms
1289 return comp_template_parms
1291 friend_parms);
1292 }
1293 else
1296 }
1297 }
1299 }
1301 /* Register the specialization SPEC as a specialization of TMPL with
1302 the indicated ARGS. IS_FRIEND indicates whether the specialization
1303 is actually just a friend declaration. Returns SPEC, or an
1304 equivalent prior declaration, if available. */
1306 static tree
1308 hashval_t hash)
1309 {
1310 tree fn;
1312 spec_entry elt;
1318 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1319 register it; we want the corresponding TEMPLATE_DECL instead.
1320 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1321 the more obvious `uses_template_parms (spec)' to avoid problems
1322 with default function arguments. In particular, given
1323 something like this:
1325 template <class T> void f(T t1, T t = T())
1327 the default argument expression is not substituted for in an
1328 instantiation unless and until it is actually needed. */
1332 /* We don't put these specializations in the hash table, but we might
1333 want to give an error about a mismatch. */
1335 else
1336 {
1344 slot =
1348 else
1350 }
1352 /* We can sometimes try to re-register a specialization that we've
1353 already got. In particular, regenerate_decl_from_template calls
1354 duplicate_decls which will update the specialization list. But,
1355 we'll still get called again here anyhow. It's more convenient
1356 to simply allow this than to try to prevent it. */
1360 {
1362 {
1365 {
1367 fn);
1369 }
1370 else
1371 {
1372 tree clone;
1373 /* This situation should occur only if the first
1374 specialization is an implicit instantiation, the
1375 second is an explicit specialization, and the
1376 implicit instantiation has not yet been used. That
1377 situation can occur if we have implicitly
1378 instantiated a member function and then specialized
1379 it later.
1381 We can also wind up here if a friend declaration that
1382 looked like an instantiation turns out to be a
1383 specialization:
1385 template <class T> void foo(T);
1386 class S { friend void foo<>(int) };
1387 template <> void foo(int);
1389 We transform the existing DECL in place so that any
1390 pointers to it become pointers to the updated
1391 declaration.
1393 If there was a definition for the template, but not
1394 for the specialization, we want this to look as if
1395 there were no definition, and vice versa. */
1398 /* The call to duplicate_decls will have applied
1399 [temp.expl.spec]:
1401 An explicit specialization of a function template
1402 is inline only if it is explicitly declared to be,
1403 and independently of whether its function template
1404 is.
1406 to the primary function; now copy the inline bits to
1407 the various clones. */
1409 {
1414 }
1418 }
1419 }
1421 {
1423 /* Dup decl failed, but this is a new definition. Set the
1424 line number so any errors match this new
1425 definition. */
1429 }
1430 }
1434 /* A specialization must be declared in the same namespace as the
1435 template it is specializing. */
1441 {
1449 /* TMPL is a forward declaration of a template function; keep a list
1450 of all specializations in case we need to reassign them to a friend
1451 template later in tsubst_friend_function. */
1454 }
1457 }
1459 /* Returns true iff two spec_entry nodes are equivalent. Only compares the
1460 TMPL and ARGS members, ignores SPEC. */
1462 static int
1464 {
1470 }
1472 /* Returns a hash for a template TMPL and template arguments ARGS. */
1474 static hashval_t
1476 {
1479 }
1481 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1482 ignoring SPEC. */
1484 static hashval_t
1486 {
1489 }
1491 /* Recursively calculate a hash value for a template argument ARG, for use
1492 in the hash tables of template specializations. */
1494 hashval_t
1496 {
1508 /* We can get one of these when re-hashing a previous entry in the middle
1509 of substituting into a pack expansion. Just look through it. */
1518 {
1526 {
1531 }
1553 {
1556 {
1559 }
1561 }
1565 {
1568 }
1579 val = iterative_hash_template_arg
1591 val);
1593 val);
1602 /* A lambda can't appear in a template arg, but don't crash on
1603 erroneous input. */
1615 /* Now hash operands as usual. */
1620 }
1623 {
1627 val);
1630 /* Otherwise just compare the types during lookup. */
1639 {
1644 }
1645 }
1648 }
1650 /* Unregister the specialization SPEC as a specialization of TMPL.
1651 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1652 if the SPEC was listed as a specialization of TMPL.
1654 Note that SPEC has been ggc_freed, so we can't look inside it. */
1656 bool
1658 {
1660 spec_entry elt;
1668 {
1673 }
1676 }
1678 /* Like register_specialization, but for local declarations. We are
1679 registering SPEC, an instantiation of TMPL. */
1681 static void
1683 {
1688 }
1690 /* TYPE is a class type. Returns true if TYPE is an explicitly
1691 specialized class. */
1693 bool
1695 {
1699 }
1701 /* Print the list of functions at FNS, going through all the overloads
1702 for each element of the list. Alternatively, FNS can not be a
1703 TREE_LIST, in which case it will be printed together with all the
1704 overloads.
1706 MORE and *STR should respectively be FALSE and NULL when the function
1707 is called from the outside. They are used internally on recursive
1708 calls. print_candidates manages the two parameters and leaves NULL
1709 in *STR when it ends. */
1711 static void
1713 {
1719 {
1723 }
1724 else
1725 {
1728 {
1729 /* Pick the prefix string. */
1731 {
1735 }
1739 }
1742 }
1745 {
1748 }
1749 }
1751 /* Print the list of candidate FNS in an error message. FNS can also
1752 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1754 void
1756 {
1760 }
1762 /* Returns the template (one of the functions given by TEMPLATE_ID)
1763 which can be specialized to match the indicated DECL with the
1764 explicit template args given in TEMPLATE_ID. The DECL may be
1765 NULL_TREE if none is available. In that case, the functions in
1766 TEMPLATE_ID are non-members.
1768 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1769 specialization of a member template.
1771 The TEMPLATE_COUNT is the number of references to qualifying
1772 template classes that appeared in the name of the function. See
1773 check_explicit_specialization for a more accurate description.
1775 TSK indicates what kind of template declaration (if any) is being
1776 declared. TSK_TEMPLATE indicates that the declaration given by
1777 DECL, though a FUNCTION_DECL, has template parameters, and is
1778 therefore a template function.
1780 The template args (those explicitly specified and those deduced)
1781 are output in a newly created vector *TARGS_OUT.
1783 If it is impossible to determine the result, an error message is
1784 issued. The error_mark_node is returned to indicate failure. */
1786 static tree
1788 tree decl,
1792 tmpl_spec_kind tsk)
1793 {
1794 tree fns;
1795 tree targs;
1796 tree explicit_targs;
1798 /* A TREE_LIST of templates of which DECL may be a specialization.
1799 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1800 corresponding TREE_PURPOSE is the set of template arguments that,
1801 when used to instantiate the template, would produce a function
1802 with the signature of DECL. */
1812 /* We shouldn't be specializing a member template of an
1813 unspecialized class template; we already gave an error in
1814 check_specialization_scope, now avoid crashing. */
1817 {
1820 }
1828 /* Check for baselinks. */
1833 {
1836 }
1838 /* Count the number of template headers specified for this
1839 specialization. */
1847 {
1851 {
1852 tree decl_arg_types;
1853 tree fn_arg_types;
1854 tree insttype;
1856 /* In case of explicit specialization, we need to check if
1857 the number of template headers appearing in the specialization
1858 is correct. This is usually done in check_explicit_specialization,
1859 but the check done there cannot be exhaustive when specializing
1860 member functions. Consider the following code:
1862 template <> void A<int>::f(int);
1863 template <> template <> void A<int>::f(int);
1865 Assuming that A<int> is not itself an explicit specialization
1866 already, the first line specializes "f" which is a non-template
1867 member function, whilst the second line specializes "f" which
1868 is a template member function. So both lines are syntactically
1869 correct, and check_explicit_specialization does not reject
1870 them.
1872 Here, we can do better, as we are matching the specialization
1873 against the declarations. We count the number of template
1874 headers, and we check if they match TEMPLATE_COUNT + 1
1875 (TEMPLATE_COUNT is the number of qualifying template classes,
1876 plus there must be another header for the member template
1877 itself).
1879 Notice that if header_count is zero, this is not a
1880 specialization but rather a template instantiation, so there
1881 is no check we can perform here. */
1885 /* Check that the number of template arguments at the
1886 innermost level for DECL is the same as for FN. */
1894 /* DECL might be a specialization of FN. */
1898 /* For a non-static member function, we need to make sure
1899 that the const qualification is the same. Since
1900 get_bindings does not try to merge the "this" parameter,
1901 we must do the comparison explicitly. */
1907 /* Skip the "this" parameter and, for constructors of
1908 classes with virtual bases, the VTT parameter. A
1909 full specialization of a constructor will have a VTT
1910 parameter, but a template never will. */
1911 decl_arg_types
1913 fn_arg_types
1916 /* Function templates cannot be specializations; there are
1917 no partial specializations of functions. Therefore, if
1918 the type of DECL does not match FN, there is no
1919 match. */
1921 {
1925 }
1927 /* See whether this function might be a specialization of this
1928 template. Suppress access control because we might be trying
1929 to make this specialization a friend, and we have already done
1930 access control for the declaration of the specialization. */
1936 /* We cannot deduce template arguments that when used to
1937 specialize TMPL will produce DECL. */
1940 /* Make sure that the deduced arguments actually work. */
1944 fn_arg_types
1949 /* Save this template, and the arguments deduced. */
1951 }
1953 /* FN is an ordinary member function, and we need a
1954 specialization of a member template. */
1955 ;
1957 /* We can get IDENTIFIER_NODEs here in certain erroneous
1958 cases. */
1959 ;
1961 /* This is just an ordinary non-member function. Nothing can
1962 be a specialization of that. */
1963 ;
1965 /* Cannot specialize functions that are created implicitly. */
1966 ;
1967 else
1968 {
1969 tree decl_arg_types;
1971 /* This is an ordinary member function. However, since
1972 we're here, we can assume it's enclosing class is a
1973 template class. For example,
1975 template <typename T> struct S { void f(); };
1976 template <> void S<int>::f() {}
1978 Here, S<int>::f is a non-template, but S<int> is a
1979 template class. If FN has the same type as DECL, we
1980 might be in business. */
1983 /* Its enclosing class is an explicit specialization
1984 of a template class. This is not a candidate. */
1989 /* The return types differ. */
1992 /* Adjust the type of DECL in case FN is a static member. */
1999 decl_arg_types))
2000 /* They match! */
2002 }
2003 }
2006 {
2007 /* We have:
2009 [temp.expl.spec]
2011 It is possible for a specialization with a given function
2012 signature to be instantiated from more than one function
2013 template. In such cases, explicit specification of the
2014 template arguments must be used to uniquely identify the
2015 function template specialization being specialized.
2017 Note that here, there's no suggestion that we're supposed to
2018 determine which of the candidate templates is most
2019 specialized. However, we, also have:
2021 [temp.func.order]
2023 Partial ordering of overloaded function template
2024 declarations is used in the following contexts to select
2025 the function template to which a function template
2026 specialization refers:
2028 -- when an explicit specialization refers to a function
2029 template.
2031 So, we do use the partial ordering rules, at least for now.
2032 This extension can only serve to make invalid programs valid,
2033 so it's safe. And, there is strong anecdotal evidence that
2034 the committee intended the partial ordering rules to apply;
2035 the EDG front end has that behavior, and John Spicer claims
2036 that the committee simply forgot to delete the wording in
2037 [temp.expl.spec]. */
2040 {
2043 }
2044 }
2047 {
2055 }
2059 {
2065 }
2067 /* We have one, and exactly one, match. */
2069 {
2072 /* DECL is a re-declaration or partial instantiation of a template
2073 function. */
2076 /* It was a specialization of an ordinary member function in a
2077 template class. */
2079 }
2081 /* It was a specialization of a template. */
2084 {
2089 }
2090 else
2093 }
2095 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2096 but with the default argument values filled in from those in the
2097 TMPL_TYPES. */
2099 static tree
2101 tree tmpl_types)
2102 {
2103 tree new_spec_types;
2111 /* Substitute into the rest of the list. */
2112 new_spec_types =
2116 /* Add the default argument for this parameter. */
2119 new_spec_types);
2120 }
2122 /* DECL is an explicit specialization. Replicate default arguments
2123 from the template it specializes. (That way, code like:
2125 template <class T> void f(T = 3);
2126 template <> void f(double);
2127 void g () { f (); }
2129 works, as required.) An alternative approach would be to look up
2130 the correct default arguments at the call-site, but this approach
2131 is consistent with how implicit instantiations are handled. */
2133 static void
2135 {
2136 tree tmpl;
2137 tree spec_types;
2138 tree tmpl_types;
2139 tree new_spec_types;
2140 tree old_type;
2141 tree new_type;
2142 tree t;
2147 /* See if there's anything we need to do. */
2160 {
2161 /* Remove the this pointer, but remember the object's type for
2162 CV quals. */
2168 {
2169 /* DECL may contain more parameters than TMPL due to the extra
2170 in-charge parameter in constructors and destructors. */
2173 }
2175 {
2178 }
2179 }
2181 /* Compute the merged default arguments. */
2182 new_spec_types =
2185 /* Compute the new FUNCTION_TYPE. */
2187 {
2191 new_spec_types);
2194 /* Put the in-charge parameter back. */
2197 new_spec_types);
2201 new_spec_types);
2202 }
2203 else
2205 new_spec_types);
2211 }
2213 /* Return the number of template headers we expect to see for a definition
2214 or specialization of CTYPE or one of its non-template members. */
2216 int
2218 {
2222 {
2223 /* You're supposed to have one `template <...>' for every
2224 template class, but you don't need one for a full
2225 specialization. For example:
2227 template <class T> struct S{};
2228 template <> struct S<int> { void f(); };
2229 void S<int>::f () {}
2231 is correct; there shouldn't be a `template <>' for the
2232 definition of `S<int>::f'. */
2234 /* If CTYPE does not have template information of any
2235 kind, then it is not a template, nor is it nested
2236 within a template. */
2244 }
2247 }
2249 /* Do a simple sanity check on the template headers that precede the
2250 variable declaration DECL. */
2252 void
2254 {
2261 {
2267 "members of an explicitly specialized class are defined "
2269 }
2270 }
2272 /* Check to see if the function just declared, as indicated in
2273 DECLARATOR, and in DECL, is a specialization of a function
2274 template. We may also discover that the declaration is an explicit
2275 instantiation at this point.
2277 Returns DECL, or an equivalent declaration that should be used
2278 instead if all goes well. Issues an error message if something is
2279 amiss. Returns error_mark_node if the error is not easily
2280 recoverable.
2282 FLAGS is a bitmask consisting of the following flags:
2284 2: The function has a definition.
2285 4: The function is a friend.
2287 The TEMPLATE_COUNT is the number of references to qualifying
2288 template classes that appeared in the name of the function. For
2289 example, in
2291 template <class T> struct S { void f(); };
2292 void S<int>::f();
2294 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2295 classes are not counted in the TEMPLATE_COUNT, so that in
2297 template <class T> struct S {};
2298 template <> struct S<int> { void f(); }
2299 template <> void S<int>::f();
2301 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2302 invalid; there should be no template <>.)
2304 If the function is a specialization, it is marked as such via
2305 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2306 is set up correctly, and it is added to the list of specializations
2307 for that template. */
2309 tree
2311 tree decl,
2314 {
2322 tmpl_spec_kind tsk;
2325 {
2328 else
2330 }
2331 else
2335 {
2338 {
2341 }
2343 {
2345 /* This could be something like:
2347 template <class T> void f(T);
2348 class S { friend void f<>(int); } */
2350 else
2351 {
2352 /* This case handles bogus declarations like template <>
2353 template <class T> void f<int>(); */
2356 declarator);
2358 }
2359 }
2363 /* The error has already been reported in
2364 check_specialization_scope. */
2370 /* Fall through. */
2383 decl);
2386 else
2390 /* Fall through. */
2395 else
2401 {
2402 /* This case handles bogus declarations like template <>
2403 template <class T> void f<int>(); */
2408 else
2410 declarator);
2412 }
2415 /* This is a specialization of a member template, without
2416 specialization the containing class. Something like:
2418 template <class T> struct S {
2419 template <class U> void f (U);
2420 };
2421 template <> template <class U> void S<int>::f(U) {}
2423 That's a specialization -- but of the entire template. */
2429 }
2432 {
2436 {
2440 }
2441 }
2444 {
2448 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2450 {
2451 tree fns;
2456 else
2457 {
2458 /* If there is no class context, the explicit instantiation
2459 must be at namespace scope. */
2462 /* Find the namespace binding, using the declaration
2463 context. */
2467 {
2470 }
2471 else
2472 {
2478 }
2479 }
2482 }
2488 {
2490 /* A specialization in class scope. This is invalid,
2491 but the error will already have been flagged by
2492 check_specialization_scope. */
2494 else
2495 {
2496 /* It's not valid to write an explicit instantiation in
2497 class scope, e.g.:
2499 class C { template void f(); }
2501 This case is caught by the parser. However, on
2502 something like:
2504 template class C { void f(); };
2506 (which is invalid) we can get here. The error will be
2507 issued later. */
2508 ;
2509 }
2512 }
2515 IDENTIFIER_NODE))
2516 {
2517 /* Find the list of functions in ctype that have the same
2518 name as the declared function. */
2524 {
2529 {
2530 /* From [temp.expl.spec]:
2532 If such an explicit specialization for the member
2533 of a class template names an implicitly-declared
2534 special member function (clause _special_), the
2535 program is ill-formed.
2537 Similar language is found in [temp.explicit]. */
2540 }
2543 }
2546 {
2550 }
2551 else
2552 {
2554 tree ovl;
2556 /* For a type-conversion operator, we cannot do a
2557 name-based lookup. We might be looking for `operator
2558 int' which will be a specialization of `operator T'.
2559 So, we find *all* the conversion operators, and then
2560 select from them. */
2568 {
2570 /* There are no more conversion functions. */
2573 /* Glue all these conversion functions together
2574 with those we already have. */
2577 }
2578 }
2581 {
2584 }
2585 else
2587 }
2589 /* Figure out what exactly is being specialized at this point.
2590 Note that for an explicit instantiation, even one for a
2591 member function, we cannot tell apriori whether the
2592 instantiation is for a member template, or just a member
2593 function of a template class. Even if a member template is
2594 being instantiated, the member template arguments may be
2595 elided if they can be deduced from the rest of the
2596 declaration. */
2599 member_specialization,
2600 template_count,
2601 tsk);
2604 /* We couldn't figure out what this declaration was
2605 specializing. */
2607 else
2608 {
2612 {
2613 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2614 is done by do_decl_instantiation later. */
2620 {
2621 /* If TMPL is not the most general template (for
2622 example, if TMPL is a friend template that is
2623 injected into namespace scope), then there will
2624 be too many levels of TARGS. Remove some of them
2625 here. */
2627 tree new_targs;
2634 }
2637 }
2639 /* If we thought that the DECL was a member function, but it
2640 turns out to be specializing a static member function,
2641 make DECL a static member function as well. */
2646 /* If this is a specialization of a member template of a
2647 template class, we want to return the TEMPLATE_DECL, not
2648 the specialization of it. */
2650 {
2655 {
2656 tree parm;
2660 /* We want to use the argument list specified in the
2661 definition, not in the original declaration. */
2666 }
2669 }
2671 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2674 /* Inherit default function arguments from the template
2675 DECL is specializing. */
2678 /* This specialization has the same protection as the
2679 template it specializes. */
2683 /* 7.1.1-1 [dcl.stc]
2685 A storage-class-specifier shall not be specified in an
2686 explicit specialization...
2688 The parser rejects these, so unless action is taken here,
2689 explicit function specializations will always appear with
2690 global linkage.
2692 The action recommended by the C++ CWG in response to C++
2693 defect report 605 is to make the storage class and linkage
2694 of the explicit specialization match the templated function:
2696 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2697 */
2699 {
2703 /* This specialization has the same linkage and visibility as
2704 the function template it specializes. */
2707 {
2710 }
2713 {
2716 }
2717 }
2719 /* If DECL is a friend declaration, declared using an
2720 unqualified name, the namespace associated with DECL may
2721 have been set incorrectly. For example, in:
2723 template <typename T> void f(T);
2724 namespace N {
2725 struct S { friend void f<int>(int); }
2726 }
2728 we will have set the DECL_CONTEXT for the friend
2729 declaration to N, rather than to the global namespace. */
2734 /* This is not really a declaration of a specialization.
2735 It's just the name of an instantiation. But, it's not
2736 a request for an instantiation, either. */
2739 /* This is indeed a specialization. In case of constructors
2740 and destructors, we need in-charge and not-in-charge
2741 versions in V3 ABI. */
2744 /* Register this specialization so that we can find it
2745 again. */
2747 }
2748 }
2751 }
2753 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2754 parameters. These are represented in the same format used for
2755 DECL_TEMPLATE_PARMS. */
2757 int
2759 {
2760 const_tree p1;
2761 const_tree p2;
2769 {
2781 {
2785 /* If either of the template parameters are invalid, assume
2786 they match for the sake of error recovery. */
2799 }
2800 }
2803 /* One set of parameters has more parameters lists than the
2804 other. */
2808 }
2810 /* Determine whether PARM is a parameter pack. */
2812 bool
2814 {
2815 /* Determine if we have a non-type template parameter pack. */
2822 /* If this is a list of template parameters, we could get a
2823 TYPE_DECL or a TEMPLATE_DECL. */
2827 /* Otherwise it must be a type template parameter. */
2831 }
2833 /* Determine if T is a function parameter pack. */
2835 bool
2837 {
2841 }
2843 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
2844 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
2846 tree
2848 {
2855 }
2857 /* Return true iff the function parameter PARAM_DECL was expanded
2858 from the function parameter pack PACK. */
2860 bool
2862 {
2867 /* The parameter pack and its pack arguments have the same
2868 DECL_PARM_INDEX. */
2870 }
2872 /* Determine whether ARGS describes a variadic template args list,
2873 i.e., one that is terminated by a template argument pack. */
2875 static bool
2877 {
2879 tree last_parm;
2893 }
2895 /* Generate a new name for the parameter pack name NAME (an
2896 IDENTIFIER_NODE) that incorporates its */
2898 static tree
2900 {
2901 /* Munge the name to include the parameter index. */
2902 #define NUMBUF_LEN 128
2914 }
2916 /* Return true if T is a primary function, class or alias template
2917 instantiation. */
2919 bool
2921 {
2938 }
2940 /* Return true if PARM is a template template parameter. */
2942 bool
2944 {
2946 }
2948 /* Return true iff PARM is a DECL representing a type template
2949 parameter. */
2951 bool
2953 {
2958 }
2960 /* Return the template parameters of T if T is a
2961 primary template instantiation, NULL otherwise. */
2963 tree
2965 {
2970 parms = INNERMOST_TEMPLATE_PARMS
2974 }
2976 /* Return the template parameters of the LEVELth level from the full list
2977 of template parameters PARMS. */
2979 tree
2981 {
2982 tree p;
2993 }
2995 /* Returns the template arguments of T if T is a template instantiation,
2996 NULL otherwise. */
2998 tree
3000 {
3008 }
3010 /* Return the argument pack elements of T if T is a template argument pack,
3011 NULL otherwise. */
3013 tree
3015 {
3021 }
3023 /* Structure used to track the progress of find_parameter_packs_r. */
3024 struct find_parameter_pack_data
3025 {
3026 /* TREE_LIST that will contain all of the parameter packs found by
3027 the traversal. */
3030 /* Set of AST nodes that have been visited by the traversal. */
3032 };
3034 /* Identifies all of the argument packs that occur in a template
3035 argument and appends them to the TREE_LIST inside DATA, which is a
3036 find_parameter_pack_data structure. This is a subroutine of
3037 make_pack_expansion and uses_parameter_packs. */
3038 static tree
3040 {
3046 /* Handle type aliases/typedefs. */
3051 {
3058 }
3060 /* Identify whether this is a parameter pack or not. */
3062 {
3077 {
3078 /* We don't want to walk into the type of a PARM_DECL,
3079 because we don't want to see the type parameter pack. */
3082 }
3089 /* Not a parameter pack. */
3091 }
3094 {
3095 /* Add this parameter pack to the list. */
3097 }
3103 /* This switch statement will return immediately if we don't find a
3104 parameter pack. */
3106 {
3111 /* Check the template itself. */
3114 /* Check the template arguments. */
3130 /* Fall through. */
3172 }
3175 }
3177 /* Determines if the expression or type T uses any parameter packs. */
3178 bool
3180 {
3188 }
3190 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3191 representation a base-class initializer into a parameter pack
3192 expansion. If all goes well, the resulting node will be an
3193 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3194 respectively. */
3195 tree
3197 {
3198 tree result;
3207 {
3208 /* The only time we will see a TREE_LIST here is for a base
3209 class initializer. In this case, the TREE_PURPOSE will be a
3210 _TYPE node (representing the base class expansion we're
3211 initializing) and the TREE_VALUE will be a TREE_LIST
3212 containing the initialization arguments.
3214 The resulting expansion looks somewhat different from most
3215 expansions. Rather than returning just one _EXPANSION, we
3216 return a TREE_LIST whose TREE_PURPOSE is a
3217 TYPE_PACK_EXPANSION containing the bases that will be
3218 initialized. The TREE_VALUE will be identical to the
3219 original TREE_VALUE, which is a list of arguments that will
3220 be passed to each base. We do not introduce any new pack
3221 expansion nodes into the TREE_VALUE (although it is possible
3222 that some already exist), because the TREE_PURPOSE and
3223 TREE_VALUE all need to be expanded together with the same
3224 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3225 resulting TREE_PURPOSE will mention the parameter packs in
3226 both the bases and the arguments to the bases. */
3227 tree purpose;
3228 tree value;
3231 /* Determine which parameter packs will be used by the base
3232 class expansion. */
3239 {
3243 }
3246 {
3247 /* Collect the sets of parameter packs used in each of the
3248 initialization arguments. */
3250 {
3251 /* Determine which parameter packs will be expanded in this
3252 argument. */
3255 }
3256 }
3260 /* Create the pack expansion type for the base type. */
3265 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3266 they will rarely be compared to anything. */
3270 }
3275 /* Build the PACK_EXPANSION_* node. */
3276 result = for_types
3281 {
3282 /* Propagate type and const-expression information. */
3285 }
3286 else
3287 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3288 they will rarely be compared to anything. */
3291 /* Determine which parameter packs will be expanded. */
3297 /* Make sure we found some parameter packs. */
3299 {
3302 else
3305 }
3311 }
3313 /* Checks T for any "bare" parameter packs, which have not yet been
3314 expanded, and issues an error if any are found. This operation can
3315 only be done on full expressions or types (e.g., an expression
3316 statement, "if" condition, etc.), because we could have expressions like:
3318 foo(f(g(h(args)))...)
3320 where "args" is a parameter pack. check_for_bare_parameter_packs
3321 should not be called for the subexpressions args, h(args),
3322 g(h(args)), or f(g(h(args))), because we would produce erroneous
3323 error messages.
3325 Returns TRUE and emits an error if there were bare parameter packs,
3326 returns FALSE otherwise. */
3327 bool
3329 {
3345 {
3348 {
3357 else
3362 else
3366 }
3369 }
3372 }
3374 /* Expand any parameter packs that occur in the template arguments in
3375 ARGS. */
3376 tree
3378 {
3384 /* First, determine if we need to expand anything, and the number of
3385 slots we'll need. */
3387 {
3392 {
3396 else
3398 }
3399 else
3400 {
3402 num_result_args++;
3403 }
3404 }
3406 /* If no expansion is necessary, we're done. */
3410 /* Expand arguments. */
3413 non_default_args_count =
3416 {
3419 {
3426 }
3427 else
3428 {
3431 }
3432 }
3436 }
3438 /* Checks if DECL shadows a template parameter.
3440 [temp.local]: A template-parameter shall not be redeclared within its
3441 scope (including nested scopes).
3443 Emits an error and returns TRUE if the DECL shadows a parameter,
3444 returns FALSE otherwise. */
3446 bool
3448 {
3449 tree olddecl;
3451 /* If we're not in a template, we can't possibly shadow a template
3452 parameter. */
3456 /* Figure out what we're shadowing. */
3461 /* If there's no previous binding for this name, we're not shadowing
3462 anything, let alone a template parameter. */
3466 /* If we're not shadowing a template parameter, we're done. Note
3467 that OLDDECL might be an OVERLOAD (or perhaps even an
3468 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3469 node. */
3473 /* We check for decl != olddecl to avoid bogus errors for using a
3474 name inside a class. We check TPFI to avoid duplicate errors for
3475 inline member templates. */
3483 }
3485 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3486 ORIG_LEVEL, DECL, and TYPE. */
3488 static tree
3492 tree decl,
3493 tree type)
3494 {
3505 }
3507 /* Find the canonical type parameter for the given template type
3508 parameter. Returns the canonical type parameter, which may be TYPE
3509 if no such parameter existed. */
3511 static tree
3513 {
3514 tree list;
3528 else
3529 {
3534 }
3535 }
3537 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3538 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3539 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3540 new one is created. */
3542 static tree
3544 tsubst_flags_t complain)
3545 {
3550 {
3569 /* Template template parameters need this. */
3574 }
3577 }
3579 /* Process information from new template parameter PARM and append it
3580 to the LIST being built. This new parameter is a non-type
3581 parameter iff IS_NON_TYPE is true. This new parameter is a
3582 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3583 is in PARM_LOC. NUM_TEMPLATE_PARMS is the size of the template
3584 parameter list PARM belongs to. This is used used to create a
3585 proper canonical type for the type of PARM that is to be created,
3586 iff PARM is a type. If the size is not known, this parameter shall
3587 be set to 0. */
3589 tree
3592 {
3594 tree defval;
3595 tree err_parm_list;
3602 {
3606 {
3610 else
3612 }
3615 }
3616 else
3620 {
3626 {
3630 }
3631 else
3632 {
3633 /* [temp.param]
3635 The top-level cv-qualifiers on the template-parameter are
3636 ignored when determining its type. */
3639 {
3643 }
3646 {
3647 /* This template parameter is not a parameter pack, but it
3648 should be. Complain about "bare" parameter packs. */
3651 /* Recover by calling this a parameter pack. */
3653 }
3654 }
3656 /* A template parameter is not modifiable. */
3665 processing_template_decl,
3670 }
3671 else
3672 {
3673 tree t;
3677 {
3679 /* This is for distinguishing between real templates and template
3680 template parameters */
3684 }
3685 else
3686 {
3688 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3691 }
3698 processing_template_decl,
3702 }
3708 }
3710 /* The end of a template parameter list has been reached. Process the
3711 tree list into a parameter vector, converting each parameter into a more
3712 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3713 as PARM_DECLs. */
3715 tree
3717 {
3722 current_template_parms
3727 {
3731 }
3736 }
3738 /* end_template_decl is called after a template declaration is seen. */
3740 void
3742 {
3748 /* This matches the pushlevel in begin_template_parm_list. */
3753 }
3755 /* Takes a TREE_LIST representing a template parameter and convert it
3756 into an argument suitable to be passed to the type substitution
3757 functions. Note that If the TREE_LIST contains an error_mark
3758 node, the returned argument is error_mark_node. */
3760 static tree
3762 {
3775 {
3779 {
3780 /* Turn this argument into a TYPE_ARGUMENT_PACK
3781 with a single element, which expands T. */
3783 #ifdef ENABLE_CHECKING
3784 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3786 #endif
3791 }
3792 }
3793 else
3794 {
3798 {
3799 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3800 with a single element, which expands T. */
3803 #ifdef ENABLE_CHECKING
3804 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3806 #endif
3812 }
3813 }
3815 }
3817 /* This function returns TRUE if PARM_PACK is a template parameter
3818 pack and if ARG_PACK is what template_parm_to_arg returned when
3819 passed PARM_PACK. */
3821 static bool
3823 {
3824 /* For clarity in the comments below let's use the representation
3825 argument_pack<elements>' to denote an argument pack and its
3826 elements.
3828 In the 'if' block below, we want to detect cases where
3829 ARG_PACK is argument_pack<PARM_PACK...>. I.e, we want to
3830 check if ARG_PACK is an argument pack which sole element is
3831 the expansion of PARM_PACK. That argument pack is typically
3832 created by template_parm_to_arg when passed a parameter
3833 pack. */
3838 {
3843 /* The argument pack that the parameter maps to is just an
3844 expansion of the parameter itself, such as one would
3845 find in the implicit typedef of a class inside the
3846 class itself. Consider this parameter "unsubstituted",
3847 so that we will maintain the outer pack expansion. */
3849 }
3851 }
3853 /* Within the declaration of a template, return all levels of template
3854 parameters that apply. The template parameters are represented as
3855 a TREE_VEC, in the form documented in cp-tree.h for template
3856 arguments. */
3858 static tree
3860 {
3861 tree header;
3866 /* If there is only one level of template parameters, we do not
3867 create a TREE_VEC of TREE_VECs. Instead, we return a single
3868 TREE_VEC containing the arguments. */
3873 {
3881 #ifdef ENABLE_CHECKING
3883 #endif
3887 else
3889 }
3892 /* This can happen for template parms of a template template
3893 parameter, e.g:
3895 template<template<class T, class U> class TT> struct S;
3897 Consider the level of the parms of TT; T and U both have
3898 level 2; TT has no template parm of level 1. So in this case
3899 the first element of full_template_args is NULL_TREE. If we
3900 leave it like this TMPL_ARG_DEPTH on args returns 1 instead
3901 of 2. This will make tsubst wrongly consider that T and U
3902 have level 1. Instead, let's create a dummy vector as the
3903 first element of full_template_args so that TMPL_ARG_DEPTH
3904 returns the correct depth for args. */
3907 }
3909 /* Update the declared TYPE by doing any lookups which were thought to be
3910 dependent, but are not now that we know the SCOPE of the declarator. */
3912 tree
3914 {
3925 /* Don't bother building up the args in this case. */
3927 {
3928 /* tsubst in the args corresponding to the template parameters,
3929 including auto if present. Most things will be unchanged, but
3930 make_typename_type and tsubst_qualified_id will resolve
3931 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
3934 tree pushed;
3936 {
3940 }
3945 }
3951 {
3954 else
3956 }
3958 }
3960 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
3961 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
3962 a member template. Used by push_template_decl below. */
3964 static tree
3966 {
3974 }
3976 struct template_parm_data
3977 {
3978 /* The level of the template parameters we are currently
3979 processing. */
3982 /* The index of the specialization argument we are currently
3983 processing. */
3986 /* An array whose size is the number of template parameters. The
3987 elements are nonzero if the parameter has been used in any one
3988 of the arguments processed so far. */
3991 /* An array whose size is the number of template arguments. The
3992 elements are nonzero if the argument makes use of template
3993 parameters of this level. */
3995 };
3997 /* Subroutine of push_template_decl used to see if each template
3998 parameter in a partial specialization is used in the explicit
3999 argument list. If T is of the LEVEL given in DATA (which is
4000 treated as a template_parm_data*), then DATA->PARMS is marked
4001 appropriately. */
4003 static int
4005 {
4011 {
4014 }
4015 else
4016 {
4019 }
4022 {
4025 }
4027 /* Return zero so that for_each_template_parm will continue the
4028 traversal of the tree; we want to mark *every* template parm. */
4030 }
4032 /* Process the partial specialization DECL. */
4034 static tree
4036 {
4042 tree inner_parms;
4043 tree inst;
4056 /* We check that each of the template parameters given in the
4057 partial specialization is used in the argument list to the
4058 specialization. For example:
4060 template <class T> struct S;
4061 template <class T> struct S<T*>;
4063 The second declaration is OK because `T*' uses the template
4064 parameter T, whereas
4066 template <class T> struct S<int>;
4068 is no good. Even trickier is:
4070 template <class T>
4071 struct S1
4072 {
4073 template <class U>
4074 struct S2;
4075 template <class U>
4076 struct S2<T>;
4077 };
4079 The S2<T> declaration is actually invalid; it is a
4080 full-specialization. Of course,
4082 template <class U>
4083 struct S2<T (*)(U)>;
4085 or some such would have been OK. */
4093 {
4098 NULL,
4100 }
4103 {
4104 /* One of the template parms was not used in the
4105 specialization. */
4107 {
4110 }
4113 }
4118 /* [temp.class.spec]
4120 The argument list of the specialization shall not be identical to
4121 the implicit argument list of the primary template. */
4128 /* A partial specialization that replaces multiple parameters of the
4129 primary template with a pack expansion is less specialized for those
4130 parameters. */
4132 {
4134 "primary template because it replaces multiple parameters "
4138 }
4140 /* [temp.class.spec]
4142 A partially specialized non-type argument expression shall not
4143 involve template parameters of the partial specialization except
4144 when the argument expression is a simple identifier.
4146 The type of a template parameter corresponding to a specialized
4147 non-type argument shall not be dependent on a parameter of the
4148 specialization.
4150 Also, we verify that pack expansions only occur at the
4151 end of the argument list. */
4155 {
4162 {
4163 /* Extract the arguments from the argument pack. We'll be
4164 iterating over these in the following loop. */
4167 }
4170 {
4172 /* Get the Jth argument in the parameter pack. */
4176 {
4177 /* Pack expansions must come at the end of the
4178 argument list. */
4181 {
4185 else
4188 }
4189 }
4192 /* We only care about the pattern. */
4198 /* This next line is the `argument expression is not just a
4199 simple identifier' condition and also the `specialized
4200 non-type argument' bit. */
4202 {
4206 arg);
4207 else
4208 {
4209 /* Look at the corresponding template parameter,
4210 marking which template parameters its type depends
4211 upon. */
4215 {
4216 /* We haven't yet initialized TPD2. Do so now. */
4218 /* The number of parameters here is the number in the
4219 main template, which, as checked in the assertion
4220 above, is NARGS. */
4224 }
4226 /* Mark the template parameters. But this time, we're
4227 looking for the template parameters of the main
4228 template, not in the specialization. */
4235 NULL,
4239 {
4240 /* The type depended on some template parameters.
4241 If they are fully specialized in the
4242 specialization, that's OK. */
4251 "type %qT of template argument %qE depends "
4253 "type %qT of template argument %qE depends "
4255 type,
4256 arg);
4257 }
4258 }
4259 }
4260 }
4261 }
4263 /* We should only get here once. */
4273 {
4277 {
4281 "partial specialization of %qT after instantiation "
4283 }
4284 }
4287 }
4289 /* Check that a template declaration's use of default arguments and
4290 parameter packs is not invalid. Here, PARMS are the template
4291 parameters. IS_PRIMARY is true if DECL is the thing declared by
4292 a primary template. IS_PARTIAL is true if DECL is a partial
4293 specialization.
4295 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4296 declaration (but not a definition); 1 indicates a declaration, 2
4297 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4298 emitted for extraneous default arguments.
4300 Returns TRUE if there were no errors found, FALSE otherwise. */
4302 bool
4305 {
4308 tree parm_level;
4311 /* [temp.param]
4313 A default template-argument shall not be specified in a
4314 function template declaration or a function template definition, nor
4315 in the template-parameter-list of the definition of a member of a
4316 class template. */
4319 /* You can't have a function template declaration in a local
4320 scope, nor you can you define a member of a class template in a
4321 local scope. */
4328 /* If this is either a friend defined in the scope of the class
4329 or a member function. */
4335 /* And, if it was a member function, it really was defined in
4336 the scope of the class. */
4339 /* We already checked these parameters when the template was
4340 declared, so there's no need to do it again now. This function
4341 was defined in class scope, but we're processing it's body now
4342 that the class is complete. */
4345 /* Core issue 226 (C++0x only): the following only applies to class
4346 templates. */
4349 {
4350 /* [temp.param]
4352 If a template-parameter has a default template-argument, all
4353 subsequent template-parameters shall have a default
4354 template-argument supplied. */
4356 {
4363 {
4373 {
4375 /* For better subsequent error-recovery, we indicate that
4376 there should have been a default argument. */
4379 }
4381 && !is_friend_decl
4382 /* Don't complain about an enclosing partial
4383 specialization. */
4388 {
4389 /* A primary class template can only have one
4390 parameter pack, at the end of the template
4391 parameter list. */
4396 else
4404 }
4405 }
4406 }
4407 }
4410 || is_partial
4411 || !is_primary
4413 /* For an ordinary class template, default template arguments are
4414 allowed at the innermost level, e.g.:
4415 template <class T = int>
4416 struct S {};
4417 but, in a partial specialization, they're not allowed even
4418 there, as we have in [temp.class.spec]:
4420 The template parameter list of a specialization shall not
4421 contain default template argument values.
4423 So, for a partial specialization, or for a function template
4424 (in C++98/C++03), we look at all of them. */
4425 ;
4426 else
4427 /* But, for a primary class template that is not a partial
4428 specialization we look at all template parameters except the
4429 innermost ones. */
4432 /* Figure out what error message to issue. */
4445 else
4449 /* If we're inside a class definition, there's no need to
4450 examine the parameters to the class itself. On the one
4451 hand, they will be checked when the class is defined, and,
4452 on the other, default arguments are valid in things like:
4453 template <class T = double>
4454 struct S { template <class U> void f(U); };
4455 Here the default argument for `S' has no bearing on the
4456 declaration of `f'. */
4458 else
4459 /* Check everything. */
4465 {
4472 {
4477 {
4479 {
4486 }
4488 /* Clear out the default argument so that we are not
4489 confused later. */
4491 }
4492 }
4494 /* At this point, if we're still interested in issuing messages,
4495 they must apply to classes surrounding the object declared. */
4499 }
4502 }
4504 /* Worker for push_template_decl_real, called via
4505 for_each_template_parm. DATA is really an int, indicating the
4506 level of the parameters we are interested in. If T is a template
4507 parameter of that level, return nonzero. */
4509 static int
4511 {
4517 else
4520 }
4522 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
4523 parameters given by current_template_args, or reuses a
4524 previously existing one, if appropriate. Returns the DECL, or an
4525 equivalent one, if it is replaced via a call to duplicate_decls.
4527 If IS_FRIEND is true, DECL is a friend declaration. */
4529 tree
4531 {
4532 tree tmpl;
4533 tree args;
4534 tree info;
4535 tree ctx;
4539 /* True if the template is a member template, in the sense of
4540 [temp.mem]. */
4546 /* See if this is a partial specialization. */
4555 /* For a friend, we want the context of the friend function, not
4556 the type of which it is a friend. */
4560 /* In the case of a virtual function, we want the class in which
4561 it is defined. */
4563 else
4564 /* Otherwise, if we're currently defining some class, the DECL
4565 is assumed to be a member of the class. */
4574 /* See if this is a primary template. */
4576 /* A friend template that specifies a class context, i.e.
4577 template <typename T> friend void A<T>::f();
4578 is not primary. */
4580 else
4584 {
4589 {
4592 }
4594 {
4596 {
4597 /* [temp.mem]
4599 A destructor shall not be a member template. */
4602 }
4609 {
4610 /* [basic.stc.dynamic.allocation]
4612 An allocation function can be a function
4613 template. ... Template allocation functions shall
4614 have two or more parameters. */
4617 }
4618 }
4624 /* alias-declaration */
4626 else
4627 {
4630 }
4631 }
4633 /* Check to see that the rules regarding the use of default
4634 arguments are not being violated. */
4638 /* Ensure that there are no parameter packs in the type of this
4639 declaration that have not been expanded. */
4641 {
4642 /* Check each of the arguments individually to see if there are
4643 any bare parameter packs. */
4649 {
4652 {
4653 /* This is a PARM_DECL that contains unexpanded parameter
4654 packs. We have already complained about this in the
4655 check_for_bare_parameter_packs call, so just replace
4656 these types with ERROR_MARK_NODE. */
4659 }
4663 }
4665 /* Check for bare parameter packs in the return type and the
4666 exception specifiers. */
4668 /* Errors were already issued, set return type to int
4669 as the frontend doesn't expect error_mark_node as
4670 the return type. */
4674 }
4679 {
4682 }
4693 {
4698 /* If DECL is a TYPE_DECL for a class-template, then there won't
4699 be DECL_LANG_SPECIFIC. The information equivalent to
4700 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
4704 {
4705 /* Since a template declaration already existed for this
4706 class-type, we must be redeclaring it here. Make sure
4707 that the redeclaration is valid. */
4709 current_template_parms);
4710 /* We don't need to create a new TEMPLATE_DECL; just use the
4711 one we already had. */
4713 }
4714 else
4715 {
4717 member_template_p);
4722 {
4723 /* A specialization of a member template of a template
4724 class. */
4728 }
4729 }
4730 }
4731 else
4732 {
4738 {
4741 }
4749 {
4750 tree new_tmpl;
4752 /* The declaration is a specialization of a member
4753 template, declared outside the class. Therefore, the
4754 innermost template arguments will be NULL, so we
4755 replace them with the arguments determined by the
4756 earlier call to check_explicit_specialization. */
4759 new_tmpl
4761 member_template_p);
4771 args,
4774 }
4776 /* Make sure the template headers we got make sense. */
4781 {
4784 }
4785 else
4787 {
4792 {
4796 else
4801 }
4806 /* Can happen in erroneous input. */
4808 else
4812 }
4814 /* Check that the parms are used in the appropriate qualifying scopes
4815 in the declarator. */
4819 {
4825 /* Avoid crash in import_export_decl. */
4828 }
4829 }
4834 /* Push template declarations for global functions and types. Note
4835 that we do not try to push a global template friend declared in a
4836 template class; such a thing may well depend on the template
4837 parameters of the class. */
4840 {
4845 /* Hide template friend classes that haven't been declared yet. */
4847 {
4850 }
4851 }
4854 {
4860 {
4863 /* It is a conversion operator. See if the type converted to
4864 depends on innermost template operands. */
4867 depth))
4869 }
4871 /* Give template template parms a DECL_CONTEXT of the template
4872 for which they are a parameter. */
4875 {
4879 }
4880 }
4882 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
4883 back to its most general template. If TMPL is a specialization,
4884 ARGS may only have the innermost set of arguments. Add the missing
4885 argument levels if necessary. */
4893 else
4894 {
4899 }
4902 }
4904 tree
4906 {
4908 }
4910 /* Called when a class template TYPE is redeclared with the indicated
4911 template PARMS, e.g.:
4913 template <class T> struct S;
4914 template <class T> struct S {}; */
4916 bool
4918 {
4919 tree tmpl;
4920 tree tmpl_parms;
4924 {
4927 }
4931 /* The type is nested in some template class. Nothing to worry
4932 about here; there are no new template parameters for the nested
4933 type. */
4937 {
4939 tmpl);
4941 }
4947 {
4957 }
4960 {
4961 tree tmpl_parm;
4962 tree parm;
4963 tree tmpl_default;
4964 tree parm_default;
4978 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
4979 TEMPLATE_DECL. */
4989 {
4993 }
4996 {
4997 /* We have in [temp.param]:
4999 A template-parameter may not be given default arguments
5000 by two different declarations in the same scope. */
5005 }
5008 /* Update the previous template parameters (which are the ones
5009 that will really count) with the new default value. */
5012 /* Update the new parameters, too; they'll be used as the
5013 parameters for any members. */
5015 }
5018 }
5020 /* Simplify EXPR if it is a non-dependent expression. Returns the
5021 (possibly simplified) expression. */
5023 static tree
5025 {
5029 /* If we're in a template, but EXPR isn't value dependent, simplify
5030 it. We're supposed to treat:
5032 template <typename T> void f(T[1 + 1]);
5033 template <typename T> void f(T[2]);
5035 as two declarations of the same function, for example. */
5040 {
5041 HOST_WIDE_INT saved_processing_template_decl;
5047 complain,
5052 }
5054 }
5056 tree
5058 {
5060 }
5062 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5063 template declaration, or a TYPE_DECL for an alias declaration. */
5065 bool
5067 {
5075 }
5077 /* Return TRUE iff is a specialization of an alias template. */
5079 bool
5081 {
5086 }
5088 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5089 must be a function or a pointer-to-function type, as specified
5090 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5091 and check that the resulting function has external linkage. */
5093 static tree
5095 {
5098 linkage_kind linkage;
5110 /* [temp.arg.nontype]/1
5112 A template-argument for a non-type, non-template template-parameter
5113 shall be one of:
5114 [...]
5115 -- the address of an object or function with external [C++11: or
5116 internal] linkage. */
5119 {
5124 else
5129 }
5132 }
5134 /* Subroutine of convert_nontype_argument.
5135 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5136 Emit an error otherwise. */
5138 static bool
5140 tsubst_flags_t complain)
5141 {
5148 {
5152 }
5154 }
5156 /* Returns TRUE iff the address of OP is value-dependent.
5158 14.6.2.4 [temp.dep.temp]:
5159 A non-integral non-type template-argument is dependent if its type is
5160 dependent or it has either of the following forms
5161 qualified-id
5162 & qualified-id
5163 and contains a nested-name-specifier which specifies a class-name that
5164 names a dependent type.
5166 We generalize this to just say that the address of a member of a
5167 dependent class is value-dependent; the above doesn't cover the
5168 address of a static data member named with an unqualified-id. */
5170 static bool
5172 {
5173 /* We could use get_inner_reference here, but there's no need;
5174 this is only relevant for template non-type arguments, which
5175 can only be expressed as &id-expression. */
5177 {
5181 }
5184 }
5186 /* The next set of functions are used for providing helpful explanatory
5187 diagnostics for failed overload resolution. Their messages should be
5188 indented by two spaces for consistency with the messages in
5189 call.c */
5191 static int
5193 {
5195 }
5197 static int
5199 {
5204 }
5206 static int
5208 {
5210 }
5212 static int
5214 {
5220 }
5222 static int
5224 {
5228 }
5230 static int
5232 {
5235 " template parameter %qD is not a parameter pack, but "
5239 }
5241 static int
5243 {
5246 " template argument %qE does not match "
5250 }
5252 static int
5254 {
5258 }
5260 static int
5262 {
5268 }
5270 static int
5272 {
5274 {
5279 else
5281 " deduced conflicting values for non-type parameter "
5283 }
5285 }
5287 static int
5289 {
5292 " variable-sized array type %qT is not "
5294 arg);
5296 }
5298 static int
5300 {
5304 arg);
5306 }
5308 static int
5310 {
5317 }
5319 static int
5321 {
5323 }
5325 static int
5327 {
5329 }
5331 static int
5334 {
5339 }
5341 static int
5344 {
5347 {
5355 }
5357 }
5359 static int
5361 {
5364 " template parameters of a template template argument are "
5367 }
5369 static int
5371 {
5377 }
5379 static int
5381 {
5386 }
5388 static int
5390 {
5394 arg);
5396 }
5398 /* Attempt to convert the non-type template parameter EXPR to the
5399 indicated TYPE. If the conversion is successful, return the
5400 converted value. If the conversion is unsuccessful, return
5401 NULL_TREE if we issued an error message, or error_mark_node if we
5402 did not. We issue error messages for out-and-out bad template
5403 parameters, but not simply because the conversion failed, since we
5404 might be just trying to do argument deduction. Both TYPE and EXPR
5405 must be non-dependent.
5407 The conversion follows the special rules described in
5408 [temp.arg.nontype], and it is much more strict than an implicit
5409 conversion.
5411 This function is called twice for each template argument (see
5412 lookup_template_class for a more accurate description of this
5413 problem). This means that we need to handle expressions which
5414 are not valid in a C++ source, but can be created from the
5415 first call (for instance, casts to perform conversions). These
5416 hacks can go away after we fix the double coercion problem. */
5418 static tree
5420 {
5421 tree expr_type;
5423 /* Detect immediately string literals as invalid non-type argument.
5424 This special-case is not needed for correctness (we would easily
5425 catch this later), but only to provide better diagnostic for this
5426 common user mistake. As suggested by DR 100, we do not mention
5427 linkage issues in the diagnostic as this is not the point. */
5428 /* FIXME we're making this OK. */
5430 {
5436 }
5438 /* Add the ADDR_EXPR now for the benefit of
5439 value_dependent_expression_p. */
5442 {
5446 }
5448 /* If we are in a template, EXPR may be non-dependent, but still
5449 have a syntactic, rather than semantic, form. For example, EXPR
5450 might be a SCOPE_REF, rather than the VAR_DECL to which the
5451 SCOPE_REF refers. Preserving the qualifying scope is necessary
5452 so that access checking can be performed when the template is
5453 instantiated -- but here we need the resolved form so that we can
5454 convert the argument. */
5465 else
5468 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
5469 to a non-type argument of "nullptr". */
5473 /* In C++11, integral or enumeration non-type template arguments can be
5474 arbitrary constant expressions. Pointer and pointer to
5475 member arguments can be general constant expressions that evaluate
5476 to a null value, but otherwise still need to be of a specific form. */
5478 {
5480 /* A PTRMEM_CST is already constant, and a valid template
5481 argument for a parameter of pointer to member type, we just want
5482 to leave it in that form rather than lower it to a
5487 {
5492 }
5493 }
5495 /* HACK: Due to double coercion, we can get a
5496 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5497 which is the tree that we built on the first call (see
5498 below when coercing to reference to object or to reference to
5499 function). We just strip everything and get to the arg.
5500 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5501 for examples. */
5503 {
5509 {
5510 /* ??? Maybe we could use convert_from_reference here, but we
5511 would need to relax its constraints because the NOP_EXPR
5512 could actually change the type to something more cv-qualified,
5513 and this is not folded by convert_from_reference. */
5524 }
5525 }
5527 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5528 parameter is a pointer to object, through decay and
5529 qualification conversion. Let's strip everything. */
5531 {
5535 /* Skip the ADDR_EXPR only if it is part of the decay for
5536 an array. Otherwise, it is part of the original argument
5537 in the source code. */
5541 }
5543 /* [temp.arg.nontype]/5, bullet 1
5545 For a non-type template-parameter of integral or enumeration type,
5546 integral promotions (_conv.prom_) and integral conversions
5547 (_conv.integral_) are applied. */
5549 {
5558 /* Notice that there are constant expressions like '4 % 0' which
5559 do not fold into integer constants. */
5561 {
5563 {
5574 /* else cxx_constant_value complained but gave us
5575 a real constant, so go ahead. */
5577 }
5578 else
5580 }
5581 }
5582 /* [temp.arg.nontype]/5, bullet 2
5584 For a non-type template-parameter of type pointer to object,
5585 qualification conversions (_conv.qual_) and the array-to-pointer
5586 conversion (_conv.array_) are applied. */
5588 {
5589 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
5591 A template-argument for a non-type, non-template template-parameter
5592 shall be one of: [...]
5594 -- the name of a non-type template-parameter;
5595 -- the address of an object or function with external linkage, [...]
5596 expressed as "& id-expression" where the & is optional if the name
5597 refers to a function or array, or if the corresponding
5598 template-parameter is a reference.
5600 Here, we do not care about functions, as they are invalid anyway
5601 for a parameter of type pointer-to-object. */
5604 /* Non-type template parameters are OK. */
5605 ;
5610 {
5612 {
5614 "because %qD is a variable, not the address of "
5618 }
5619 /* Other values, like integer constants, might be valid
5620 non-type arguments of some other type. */
5622 }
5623 else
5624 {
5625 tree decl;
5630 {
5635 }
5637 {
5642 }
5644 {
5649 }
5650 }
5659 }
5660 /* [temp.arg.nontype]/5, bullet 3
5662 For a non-type template-parameter of type reference to object, no
5663 conversions apply. The type referred to by the reference may be more
5664 cv-qualified than the (otherwise identical) type of the
5665 template-argument. The template-parameter is bound directly to the
5666 template-argument, which must be an lvalue. */
5668 {
5670 expr_type))
5674 {
5678 }
5681 {
5685 }
5687 /* [temp.arg.nontype]/1
5689 A template-argument for a non-type, non-template template-parameter
5690 shall be one of: [...]
5692 -- the address of an object or function with external linkage. */
5695 {
5698 {
5700 "because a reference variable does not have a constant "
5703 }
5704 }
5707 {
5712 }
5715 {
5720 }
5723 }
5724 /* [temp.arg.nontype]/5, bullet 4
5726 For a non-type template-parameter of type pointer to function, only
5727 the function-to-pointer conversion (_conv.func_) is applied. If the
5728 template-argument represents a set of overloaded functions (or a
5729 pointer to such), the matching function is selected from the set
5730 (_over.over_). */
5732 {
5733 /* If the argument is a template-id, we might not have enough
5734 context information to decay the pointer. */
5736 {
5740 }
5743 /* Null pointer values are OK in C++11. */
5751 {
5755 }
5756 }
5757 /* [temp.arg.nontype]/5, bullet 5
5759 For a non-type template-parameter of type reference to function, no
5760 conversions apply. If the template-argument represents a set of
5761 overloaded functions, the matching function is selected from the set
5762 (_over.over_). */
5764 {
5766 {
5771 }
5778 }
5779 /* [temp.arg.nontype]/5, bullet 6
5781 For a non-type template-parameter of type pointer to member function,
5782 no conversions apply. If the template-argument represents a set of
5783 overloaded member functions, the matching member function is selected
5784 from the set (_over.over_). */
5786 {
5791 /* [temp.arg.nontype] bullet 1 says the pointer to member
5792 expression must be a pointer-to-member constant. */
5796 /* There is no way to disable standard conversions in
5797 resolve_address_of_overloaded_function (called by
5798 instantiate_type). It is possible that the call succeeded by
5799 converting &B::I to &D::I (where B is a base of D), so we need
5800 to reject this conversion here.
5802 Actually, even if there was a way to disable standard conversions,
5803 it would still be better to reject them here so that we can
5804 provide a superior diagnostic. */
5806 {
5810 /* If we are just one standard conversion off, explain. */
5815 }
5816 }
5817 /* [temp.arg.nontype]/5, bullet 7
5819 For a non-type template-parameter of type pointer to data member,
5820 qualification conversions (_conv.qual_) are applied. */
5822 {
5823 /* [temp.arg.nontype] bullet 1 says the pointer to member
5824 expression must be a pointer-to-member constant. */
5831 }
5833 {
5835 {
5839 }
5841 }
5842 /* A template non-type parameter must be one of the above. */
5843 else
5846 /* Sanity check: did we actually convert the argument to the
5847 right type? */
5851 }
5853 /* Subroutine of coerce_template_template_parms, which returns 1 if
5854 PARM_PARM and ARG_PARM match using the rule for the template
5855 parameters of template template parameters. Both PARM and ARG are
5856 template parameters; the rest of the arguments are the same as for
5857 coerce_template_template_parms.
5858 */
5859 static int
5861 tree arg,
5862 tsubst_flags_t complain,
5863 tree in_decl,
5864 tree outer_args)
5865 {
5874 {
5876 /* We encounter instantiations of templates like
5877 template <template <template <class> class> class TT>
5878 class C; */
5879 {
5886 }
5887 /* Fall through. */
5892 /* Argument is a parameter pack but parameter is not. */
5897 /* The tsubst call is used to handle cases such as
5899 template <int> class C {};
5900 template <class T, template <T> class TT> class D {};
5901 D<int, C> d;
5903 i.e. the parameter list of TT depends on earlier parameters. */
5905 && !same_type_p
5912 /* Argument is a parameter pack but parameter is not. */
5919 }
5922 }
5925 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
5926 template template parameters. Both PARM_PARMS and ARG_PARMS are
5927 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
5928 or PARM_DECL.
5930 Consider the example:
5931 template <class T> class A;
5932 template<template <class U> class TT> class B;
5934 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
5935 the parameters to A, and OUTER_ARGS contains A. */
5937 static int
5939 tree arg_parms,
5940 tsubst_flags_t complain,
5941 tree in_decl,
5942 tree outer_args)
5943 {
5954 /* Determine whether we have a parameter pack at the end of the
5955 template template parameter's template parameter list. */
5957 {
5964 {
5978 }
5979 }
5985 /* Check all of the template parameters except the parameter pack at
5986 the end (if any). */
5988 {
5997 outer_args))
6000 }
6003 {
6004 /* Check each of the template parameters in the template
6005 argument against the template parameter pack at the end of
6006 the template template parameter. */
6013 {
6020 outer_args))
6022 }
6023 }
6026 }
6028 /* Verifies that the deduced template arguments (in TARGS) for the
6029 template template parameters (in TPARMS) represent valid bindings,
6030 by comparing the template parameter list of each template argument
6031 to the template parameter list of its corresponding template
6032 template parameter, in accordance with DR150. This
6033 routine can only be called after all template arguments have been
6034 deduced. It will return TRUE if all of the template template
6035 parameter bindings are okay, FALSE otherwise. */
6036 bool
6038 {
6042 /* We're dealing with template parms in this process. */
6048 {
6053 {
6058 {
6059 /* Look inside the argument pack. */
6062 }
6065 {
6069 /* Extract the next argument from the argument
6070 pack. */
6074 /* Look at the pattern of the pack expansion. */
6077 /* Extract the template parameters from the template
6078 argument. */
6084 /* Verify that we can coerce the template template
6085 parameters from the template argument to the template
6086 parameter. This requires an exact match. */
6088 && !coerce_template_template_parms
6090 targ_parms,
6091 tf_none,
6092 tparm,
6093 targs))
6094 {
6097 }
6098 }
6099 }
6100 }
6102 out:
6106 }
6108 /* Since type attributes aren't mangled, we need to strip them from
6109 template type arguments. */
6111 static tree
6113 {
6114 tree mv;
6121 {
6126 }
6128 }
6130 /* Convert the indicated template ARG as necessary to match the
6131 indicated template PARM. Returns the converted ARG, or
6132 error_mark_node if the conversion was unsuccessful. Error and
6133 warning messages are issued under control of COMPLAIN. This
6134 conversion is for the Ith parameter in the parameter list. ARGS is
6135 the full set of template arguments deduced so far. */
6137 static tree
6139 tree arg,
6140 tree args,
6141 tsubst_flags_t complain,
6143 tree in_decl)
6144 {
6145 tree orig_arg;
6146 tree val;
6151 {
6152 /* The template argument was the name of some
6153 member function. That's usually
6154 invalid, but static members are OK. In any
6155 case, grab the underlying fields/functions
6156 and issue an error later if required. */
6159 }
6167 /* When determining whether an argument pack expansion is a template,
6168 look at the pattern. */
6172 /* Deal with an injected-class-name used as a template template arg. */
6174 {
6177 {
6187 }
6188 }
6190 is_tmpl_type =
6206 {
6208 {
6212 }
6215 "to refer to a type member of a template parameter, "
6220 typename_type,
6221 complain);
6224 }
6226 {
6228 {
6230 {
6240 else
6242 }
6243 }
6245 }
6247 {
6249 {
6255 else
6257 }
6259 }
6262 {
6264 {
6268 /* The number of argument required is not known yet.
6269 Just accept it for now. */
6271 else
6272 {
6274 tree argparm;
6280 args))
6281 {
6284 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6285 TEMPLATE_DECL. */
6287 {
6292 }
6293 }
6294 else
6295 {
6297 {
6303 }
6306 }
6307 }
6308 }
6309 else
6311 /* We only form one instance of each template specialization.
6312 Therefore, if we use a non-canonical variant (i.e., a
6313 typedef), any future messages referring to the type will use
6314 the typedef, which is confusing if those future uses do not
6315 themselves also use the typedef. */
6318 }
6319 else
6320 {
6327 {
6330 else
6331 {
6332 /* Not sure if this is reachable, but it doesn't hurt
6333 to be robust. */
6336 }
6337 }
6339 /* We used to call digest_init here. However, digest_init
6340 will report errors, which we don't want when complain
6341 is zero. More importantly, digest_init will try too
6342 hard to convert things: for example, `0' should not be
6343 converted to pointer type at this point according to
6344 the standard. Accepting this is not merely an
6345 extension, since deciding whether or not these
6346 conversions can occur is part of determining which
6347 function template to call, or whether a given explicit
6348 argument specification is valid. */
6350 else
6359 {
6360 /* Strip typedefs from the SCOPE_REF. */
6363 complain);
6366 }
6367 }
6370 }
6372 /* Coerces the remaining template arguments in INNER_ARGS (from
6373 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6374 Returns the coerced argument pack. PARM_IDX is the position of this
6375 parameter in the template parameter list. ARGS is the original
6376 template argument list. */
6377 static tree
6380 tree args,
6381 tree inner_args,
6383 tree new_args,
6385 tree in_decl,
6386 tsubst_flags_t complain)
6387 {
6390 tree packed_args;
6391 tree argument_pack;
6401 {
6402 /* When the template parameter is a non-type template
6403 parameter pack whose type uses parameter packs, we need
6404 to look at each of the template arguments
6405 separately. Build a vector of the types for these
6406 non-type template parameters in PACKED_TYPES. */
6407 tree expansion
6415 /* Check that we have the right number of arguments. */
6419 {
6420 int needed_parms
6425 }
6427 /* If we aren't able to check the actual arguments now
6428 (because they haven't been expanded yet), we can at least
6429 verify that all of the types used for the non-type
6430 template parameter pack are, in fact, valid for non-type
6431 template parameters. */
6434 {
6437 {
6441 }
6442 }
6443 }
6445 /* Convert the remaining arguments, which will be a part of the
6446 parameter pack "parm". */
6448 {
6453 {
6454 /* When we have a vector of types (corresponding to the
6455 non-type template parameter pack that uses parameter
6456 packs in its type, as mention above), and the
6457 argument is not an expansion (which expands to a
6458 currently unknown number of arguments), clone the
6459 parm and give it the next type in PACKED_TYPES. */
6463 }
6466 {
6469 }
6470 else
6473 in_decl);
6477 }
6482 else
6483 {
6488 }
6491 #ifdef ENABLE_CHECKING
6494 #endif
6496 }
6498 /* Returns true if the template argument vector ARGS contains
6499 any pack expansions, false otherwise. */
6501 static bool
6503 {
6510 }
6512 /* Convert all template arguments to their appropriate types, and
6513 return a vector containing the innermost resulting template
6514 arguments. If any error occurs, return error_mark_node. Error and
6515 warning messages are issued under control of COMPLAIN.
6517 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6518 for arguments not specified in ARGS. Otherwise, if
6519 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
6520 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
6521 USE_DEFAULT_ARGS is false, then all arguments must be specified in
6522 ARGS. */
6524 static tree
6526 tree args,
6527 tree in_decl,
6528 tsubst_flags_t complain,
6531 {
6533 tree inner_args;
6534 tree new_args;
6535 tree new_inner_args;
6539 /* When used as a boolean value, indicates whether this is a
6540 variadic template parameter list. Since it's an int, we can also
6541 subtract it from nparms to get the number of non-variadic
6542 parameters. */
6551 /* Determine if there are any parameter packs. */
6553 {
6559 }
6562 /* If there are no parameters that follow a parameter pack, we need to
6563 expand any argument packs so that we can deduce a parameter pack from
6564 some non-packed args followed by an argument pack, as in variadic85.C.
6565 If there are such parameters, we need to leave argument packs intact
6566 so the arguments are assigned properly. This can happen when dealing
6567 with a nested class inside a partial specialization of a class
6568 template, as in variadic92.C, or when deducing a template parameter pack
6569 from a sub-declarator, as in variadic114.C. */
6576 && require_all_args
6578 && (!use_default_args
6581 {
6583 {
6585 {
6589 }
6590 else
6596 }
6599 }
6601 /* We need to evaluate the template arguments, even though this
6602 template-id may be nested within a "sizeof". */
6610 {
6611 tree arg;
6612 tree parm;
6614 /* Get the Ith template parameter. */
6618 {
6621 }
6623 /* Calculate the next argument. */
6626 else
6631 {
6632 /* All remaining arguments will be placed in the
6633 template parameter pack PARM. */
6639 /* Store this argument. */
6641 lost++;
6644 /* We are done with all of the arguments. */
6648 }
6650 {
6652 {
6653 /* We don't know how many args we have yet, just
6654 use the unconverted ones for now. */
6657 }
6658 }
6660 {
6661 /* There must be a default arg in this case. */
6664 /* The position of the first default template argument,
6665 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
6666 Record that. */
6669 }
6670 else
6674 {
6677 }
6679 /* This only occurs if there was an error in the template
6680 parameter list itself (which we would already have
6681 reported) that we are trying to recover from, e.g., a class
6682 template with a parameter list such as
6683 template<typename..., typename>. */
6685 else
6691 lost++;
6693 }
6700 #ifdef ENABLE_CHECKING
6704 #endif
6707 }
6709 /* Returns 1 if template args OT and NT are equivalent. */
6711 static int
6713 {
6720 /* For member templates */
6729 {
6746 }
6748 {
6749 /* We get here probably because we are in the middle of substituting
6750 into the pattern of a pack expansion. In that case the
6751 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
6752 interested in. So we want to use the initial pack argument for
6753 the comparison. */
6758 }
6763 else
6765 }
6767 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
6768 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
6769 NEWARG_PTR with the offending arguments if they are non-NULL. */
6771 static int
6774 {
6787 {
6792 {
6798 }
6799 }
6801 }
6803 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
6804 of template arguments. Returns 0 otherwise. */
6806 int
6808 {
6810 }
6812 static void
6814 {
6824 /* We are called both from instantiate_decl, where we've already had a
6825 tinst_level pushed, and instantiate_template, where we haven't.
6826 Compensate. */
6837 else
6846 }
6849 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
6850 ARGLIST. Valid choices for FNS are given in the cp-tree.def
6851 documentation for TEMPLATE_ID_EXPR. */
6853 tree
6855 {
6856 tree type;
6864 {
6867 }
6870 {
6872 unknown_type_node,
6874 arglist);
6876 }
6883 }
6885 /* Within the scope of a template class S<T>, the name S gets bound
6886 (in build_self_reference) to a TYPE_DECL for the class, not a
6887 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
6888 or one of its enclosing classes, and that type is a template,
6889 return the associated TEMPLATE_DECL. Otherwise, the original
6890 DECL is returned.
6892 Also handle the case when DECL is a TREE_LIST of ambiguous
6893 injected-class-names from different bases. */
6895 tree
6897 {
6901 /* DR 176: A lookup that finds an injected-class-name (10.2
6902 [class.member.lookup]) can result in an ambiguity in certain cases
6903 (for example, if it is found in more than one base class). If all of
6904 the injected-class-names that are found refer to specializations of
6905 the same class template, and if the name is followed by a
6906 template-argument-list, the reference refers to the class template
6907 itself and not a specialization thereof, and is not ambiguous. */
6909 {
6912 {
6918 }
6921 else
6923 }
6929 }
6931 /* Given an IDENTIFIER_NODE (type TEMPLATE_DECL) and a chain of
6932 parameters, find the desired type.
6934 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
6936 IN_DECL, if non-NULL, is the template declaration we are trying to
6937 instantiate.
6939 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
6940 the class we are looking up.
6942 Issue error and warning messages under control of COMPLAIN.
6944 If the template class is really a local class in a template
6945 function, then the FUNCTION_CONTEXT is the function in which it is
6946 being instantiated.
6948 ??? Note that this function is currently called *twice* for each
6949 template-id: the first time from the parser, while creating the
6950 incomplete type (finish_template_type), and the second type during the
6951 real instantiation (instantiate_template_class). This is surely something
6952 that we want to avoid. It also causes some problems with argument
6953 coercion (see convert_nontype_argument for more information on this). */
6955 static tree
6958 {
6960 tree t;
6963 spec_entry elt;
6964 hashval_t hash;
6967 {
6971 else
6972 {
6979 }
6982 }
6984 {
6987 /* If we are declaring a constructor, say A<T>::A<T>, we will get
6988 an implicit typename for the second A. Deal with it. */
6993 {
6996 }
6997 }
7000 {
7003 }
7007 {
7011 }
7013 /* Issue an error message if we didn't find a template. */
7015 {
7019 }
7022 /* Make sure it's a user visible template, if it was named by
7023 the user. */
7026 {
7028 {
7032 }
7034 }
7039 {
7040 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7041 template arguments */
7043 tree parm;
7044 tree arglist2;
7045 tree outer;
7049 /* Consider an example where a template template parameter declared as
7051 template <class T, class U = std::allocator<T> > class TT
7053 The template parameter level of T and U are one level larger than
7054 of TT. To proper process the default argument of U, say when an
7055 instantiation `TT<int>' is seen, we need to build the full
7056 arguments containing {int} as the innermost level. Outer levels,
7057 available when not appearing as default template argument, can be
7058 obtained from the arguments of the enclosing template.
7060 Suppose that TT is later substituted with std::vector. The above
7061 instantiation is `TT<int, std::allocator<T> >' with TT at
7062 level 1, and T at level 2, while the template arguments at level 1
7063 becomes {std::vector} and the inner level 2 is {int}. */
7069 /* This is an argument of the current template, so we haven't set
7070 DECL_CONTEXT yet. */
7077 complain,
7087 }
7088 else
7089 {
7091 tree gen_tmpl;
7092 tree type_decl;
7100 /* An error occured while building the template TEMPL, and a
7101 diagnostic has most certainly been emitted for that
7102 already. Let's propagate that error. */
7111 {
7112 /* We've been given an incomplete set of template arguments.
7113 For example, given:
7115 template <class T> struct S1 {
7116 template <class U> struct S2 {};
7117 template <class U> struct S2<U*> {};
7118 };
7120 we will be called with an ARGLIST of `U*', but the
7121 TEMPLATE will be `template <class T> template
7122 <class U> struct S1<T>::S2'. We must fill in the missing
7123 arguments. */
7124 arglist
7126 arglist);
7128 }
7130 /* Now we should have enough arguments. */
7133 /* From here on, we're only interested in the most general
7134 template. */
7136 /* Calculate the BOUND_ARGS. These will be the args that are
7137 actually tsubst'd into the definition to create the
7138 instantiation. */
7140 {
7141 /* We have multiple levels of arguments to coerce, at once. */
7151 {
7152 tree a;
7156 complain,
7159 else
7160 /* Outer levels should have already been coerced. */
7163 /* Don't process further if one of the levels fails. */
7165 {
7166 /* Restore the ARGLIST to its full size. */
7169 }
7173 /* We temporarily reduce the length of the ARGLIST so
7174 that coerce_template_parms will see only the arguments
7175 corresponding to the template parameters it is
7176 examining. */
7178 }
7180 /* Restore the ARGLIST to its full size. */
7184 }
7185 else
7186 arglist
7189 gen_tmpl,
7190 complain,
7195 /* We were unable to bind the arguments. */
7198 /* In the scope of a template class, explicit references to the
7199 template class refer to the type of the template, not any
7200 instantiation of it. For example, in:
7202 template <class T> class C { void f(C<T>); }
7204 the `C<T>' is just the same as `C'. Outside of the
7205 class, however, such a reference is an instantiation. */
7209 /* comp_template_args is expensive, check it last. */
7211 arglist))
7214 /* If we already have this specialization, return it. */
7226 /* If the deduced arguments are invalid, then the binding
7227 failed. */
7231 complain))
7238 {
7243 }
7253 /* Create the type. */
7255 {
7257 {
7263 }
7264 else
7265 {
7266 /* We don't want to call start_enum for this type, since
7267 the values for the enumeration constants may involve
7268 template parameters. And, no one should be interested
7269 in the enumeration constants for such a type. */
7272 }
7276 }
7278 {
7279 /* The user referred to a specialization of an alias
7280 template represented by GEN_TMPL.
7282 [temp.alias]/2 says:
7284 When a template-id refers to the specialization of an
7285 alias template, it is equivalent to the associated
7286 type obtained by substitution of its
7287 template-arguments for the template-parameters in the
7288 type-id of the alias template. */
7291 /* Note that the call above (by indirectly calling
7292 register_specialization in tsubst_decl) registers the
7293 TYPE_DECL representing the specialization of the alias
7294 template. So next time someone substitutes ARGLIST for
7295 the template parms into the alias template (GEN_TMPL),
7296 she'll get that TYPE_DECL back. */
7300 }
7302 {
7309 /* A local class. Make sure the decl gets registered properly. */
7314 /* This instantiation is another name for the primary
7315 template type. Set the TYPE_CANONICAL field
7316 appropriately. */
7319 /* Some of the template arguments require structural
7320 equality testing, so this template class requires
7321 structural equality testing. */
7323 }
7324 else
7327 /* If we called start_enum or pushtag above, this information
7328 will already be set up. */
7330 {
7337 }
7338 else
7342 {
7348 {
7351 }
7352 }
7354 /* Let's consider the explicit specialization of a member
7355 of a class template specialization that is implicitely instantiated,
7356 e.g.:
7357 template<class T>
7358 struct S
7359 {
7360 template<class U> struct M {}; //#0
7361 };
7363 template<>
7364 template<>
7365 struct S<int>::M<char> //#1
7366 {
7367 int i;
7368 };
7369 [temp.expl.spec]/4 says this is valid.
7371 In this case, when we write:
7372 S<int>::M<char> m;
7374 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
7375 the one of #0.
7377 When we encounter #1, we want to store the partial instantiation
7378 of M (template<class T> S<int>::M<T>) in it's CLASSTYPE_TI_TEMPLATE.
7380 For all cases other than this "explicit specialization of member of a
7381 class template", we just want to store the most general template into
7382 the CLASSTYPE_TI_TEMPLATE of M.
7384 This case of "explicit specialization of member of a class template"
7385 only happens when:
7386 1/ the enclosing class is an instantiation of, and therefore not
7387 the same as, the context of the most general template, and
7388 2/ we aren't looking at the partial instantiation itself, i.e.
7389 the innermost arguments are not the same as the innermost parms of
7390 the most general template.
7392 So it's only when 1/ and 2/ happens that we want to use the partial
7393 instantiation of the member template in lieu of its most general
7394 template. */
7398 /* the enclosing class must be an instantiation... */
7401 {
7402 tree partial_inst_args;
7405 partial_inst_args =
7411 use_partial_inst_tmpl =
7412 /*...and we must not be looking at the partial instantiation
7413 itself. */
7415 partial_inst_args);
7416 }
7419 /* This case is easy; there are no member templates involved. */
7421 else
7422 {
7423 /* This is a full instantiation of a member template. Find
7424 the partial instantiation of which this is an instance. */
7426 /* Temporarily reduce by one the number of levels in the ARGLIST
7427 so as to avoid comparing the last set of arguments. */
7431 /* FOUND is either a proper class type, or an alias
7432 template specialization. In the later case, it's a
7433 TYPE_DECL, resulting from the substituting of arguments
7434 for parameters in the TYPE_DECL of the alias template
7435 done earlier. So be careful while getting the template
7436 of FOUND. */
7440 }
7451 /* Note this use of the partial instantiation so we can check it
7452 later in maybe_process_partial_specialization. */
7458 /* Now that the type has been registered on the instantiations
7459 list, we set up the enumerators. Because the enumeration
7460 constants may involve the enumeration type itself, we make
7461 sure to register the type first, and then create the
7462 constants. That way, doing tsubst_expr for the enumeration
7463 constants won't result in recursive calls here; we'll find
7464 the instantiation and exit above. */
7468 /* If the type makes use of template parameters, the
7469 code that generates debugging information will crash. */
7472 /* Possibly limit visibility based on template args. */
7477 }
7478 }
7480 /* Wrapper for lookup_template_class_1. */
7482 tree
7485 {
7486 tree ret;
7492 }
7493 \f
7494 struct pair_fn_data
7495 {
7496 tree_fn_t fn;
7498 /* True when we should also visit template parameters that occur in
7499 non-deduced contexts. */
7502 };
7504 /* Called from for_each_template_parm via walk_tree. */
7506 static tree
7508 {
7521 {
7525 /* Fall through. */
7548 /* Since we're not going to walk subtrees, we have to do this
7549 explicitly here. */
7553 /* Fall through. */
7556 /* Check the return type. */
7561 /* Check the parameter types. Since default arguments are not
7562 instantiated until they are needed, the TYPE_ARG_TYPES may
7563 contain expressions that involve template parameters. But,
7564 no-one should be looking at them yet. And, once they're
7565 instantiated, they don't contain template parameters, so
7566 there's no point in looking at them then, either. */
7567 {
7568 tree parm;
7575 /* Since we've already handled the TYPE_ARG_TYPES, we don't
7576 want walk_tree walking into them itself. */
7578 }
7596 /* Fall through. */
7612 /* Record template parameters such as `T' inside `TT<T>'. */
7616 /* Fall through. */
7628 /* A template template parameter is encountered. */
7634 /* Already substituted template template parameter */
7657 /* If there's no type, then this thing must be some expression
7658 involving template parameters. */
7680 }
7682 /* We didn't find any template parameters we liked. */
7684 }
7686 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
7687 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
7688 call FN with the parameter and the DATA.
7689 If FN returns nonzero, the iteration is terminated, and
7690 for_each_template_parm returns 1. Otherwise, the iteration
7691 continues. If FN never returns a nonzero value, the value
7692 returned by for_each_template_parm is 0. If FN is NULL, it is
7693 considered to be the function which always returns 1.
7695 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
7696 parameters that occur in non-deduced contexts. When false, only
7697 visits those template parameters that can be deduced. */
7699 static int
7703 {
7707 /* Set up. */
7712 /* Walk the tree. (Conceptually, we would like to walk without
7713 duplicates, but for_each_template_parm_r recursively calls
7714 for_each_template_parm, so we would need to reorganize a fair
7715 bit to use walk_tree_without_duplicates, so we keep our own
7716 visited list.) */
7719 else
7722 for_each_template_parm_r,
7726 /* Clean up. */
7728 {
7731 }
7734 }
7736 /* Returns true if T depends on any template parameter. */
7738 int
7740 {
7767 else
7768 {
7771 }
7776 }
7778 /* Returns true iff current_function_decl is an incompletely instantiated
7779 template. Useful instead of processing_template_decl because the latter
7780 is set to 0 during fold_non_dependent_expr. */
7782 bool
7784 {
7793 }
7795 /* Returns true if T depends on any template parameter with level LEVEL. */
7797 int
7799 {
7802 }
7804 /* Returns TRUE iff INST is an instantiation we don't need to do in an
7805 ill-formed translation unit, i.e. a variable or function that isn't
7806 usable in a constant expression. */
7810 {
7814 }
7816 /* Returns TRUE iff we should refuse to instantiate DECL because it's
7817 neglectable and instantiated from within an erroneous instantiation. */
7819 static bool
7821 {
7832 }
7840 /* We're starting to instantiate D; record the template instantiation context
7841 for diagnostics and to restore it later. */
7843 int
7845 {
7849 {
7855 else
7863 }
7865 /* If the current instantiation caused problems, don't let it instantiate
7866 anything else. Do allow deduction substitution and decls usable in
7867 constant expressions. */
7884 }
7886 /* We're done instantiating this template; return to the instantiation
7887 context. */
7889 void
7891 {
7892 /* Restore the filename and line number stashed away when we started
7893 this instantiation. */
7897 }
7899 /* We're instantiating a deferred template; restore the template
7900 instantiation context in which the instantiation was requested, which
7901 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
7903 static tree
7905 {
7917 }
7919 /* Returns the TINST_LEVEL which gives the original instantiation
7920 context. */
7924 {
7930 }
7932 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
7933 vector of template arguments, as for tsubst.
7935 Returns an appropriate tsubst'd friend declaration. */
7937 static tree
7939 {
7940 tree new_friend;
7945 /* This was a friend declared with an explicit template
7946 argument list, e.g.:
7948 friend void f<>(T);
7950 to indicate that f was a template instantiation, not a new
7951 function declaration. Now, we have to figure out what
7952 instantiation of what template. */
7953 {
7955 tree new_args;
7956 tree tmpl;
7959 /* Friend functions are looked up in the containing namespace scope.
7960 We must enter that scope, to avoid finding member functions of the
7961 current class with same name. */
7976 tsk_none);
7978 }
7982 /* The NEW_FRIEND will look like an instantiation, to the
7983 compiler, but is not an instantiation from the point of view of
7984 the language. For example, we might have had:
7986 template <class T> struct S {
7987 template <class U> friend void f(T, U);
7988 };
7990 Then, in S<int>, template <class U> void f(int, U) is not an
7991 instantiation of anything. */
7997 {
8001 }
8003 /* The mangled name for the NEW_FRIEND is incorrect. The function
8004 is not a template instantiation and should not be mangled like
8005 one. Therefore, we forget the mangling here; we'll recompute it
8006 later if we need it. */
8008 {
8011 }
8014 {
8015 tree old_decl;
8016 tree new_friend_template_info;
8017 tree new_friend_result_template_info;
8018 tree ns;
8021 /* We must save some information from NEW_FRIEND before calling
8022 duplicate decls since that function will free NEW_FRIEND if
8023 possible. */
8025 new_friend_is_defn =
8030 {
8031 /* This declaration is a `primary' template. */
8034 new_friend_result_template_info
8036 }
8037 else
8040 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8044 /* Inside pushdecl_namespace_level, we will push into the
8045 current namespace. However, the friend function should go
8046 into the namespace of the template. */
8056 {
8057 /* This new friend declaration matched an existing
8058 declaration. For example, given:
8060 template <class T> void f(T);
8061 template <class U> class C {
8062 template <class T> friend void f(T) {}
8063 };
8065 the friend declaration actually provides the definition
8066 of `f', once C has been instantiated for some type. So,
8067 old_decl will be the out-of-class template declaration,
8068 while new_friend is the in-class definition.
8070 But, if `f' was called before this point, the
8071 instantiation of `f' will have DECL_TI_ARGS corresponding
8072 to `T' but not to `U', references to which might appear
8073 in the definition of `f'. Previously, the most general
8074 template for an instantiation of `f' was the out-of-class
8075 version; now it is the in-class version. Therefore, we
8076 run through all specialization of `f', adding to their
8077 DECL_TI_ARGS appropriately. In particular, they need a
8078 new set of outer arguments, corresponding to the
8079 arguments for this class instantiation.
8081 The same situation can arise with something like this:
8083 friend void f(int);
8084 template <class T> class C {
8085 friend void f(T) {}
8086 };
8088 when `C<int>' is instantiated. Now, `f(int)' is defined
8089 in the class. */
8092 /* On the other hand, if the in-class declaration does
8093 *not* provide a definition, then we don't want to alter
8094 existing definitions. We can just leave everything
8095 alone. */
8096 ;
8097 else
8098 {
8102 /* Overwrite whatever template info was there before, if
8103 any, with the new template information pertaining to
8104 the declaration. */
8108 {
8109 /* We should have called reregister_specialization in
8110 duplicate_decls. */
8115 /* Instantiate it if the global has already been used. */
8119 }
8120 else
8121 {
8122 tree t;
8124 /* Indicate that the old function template is a partial
8125 instantiation. */
8133 /* Reassign any specializations already in the hash table
8134 to the new more general template, and add the
8135 additional template args. */
8139 {
8141 spec_entry elt;
8153 register_specialization
8156 }
8158 }
8159 }
8161 /* The information from NEW_FRIEND has been merged into OLD_DECL
8162 by duplicate_decls. */
8164 }
8165 }
8166 else
8167 {
8171 /* In the code
8172 template <class T> class C {
8173 template <class U> friend void C1<U>::f (); // case 1
8174 friend void C2<T>::f (); // case 2
8175 };
8176 we only need to make sure CONTEXT is a complete type for
8177 case 2. To distinguish between the two cases, we note that
8178 CONTEXT of case 1 remains dependent type after tsubst while
8179 this isn't true for case 2. */
8189 {
8190 /* Check to see that the declaration is really present, and,
8191 possibly obtain an improved declaration. */
8197 }
8198 }
8201 }
8203 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8204 template arguments, as for tsubst.
8206 Returns an appropriate tsubst'd friend type or error_mark_node on
8207 failure. */
8209 static tree
8211 {
8212 tree friend_type;
8213 tree tmpl;
8214 tree context;
8217 {
8220 }
8225 {
8228 else
8230 }
8232 /* Look for a class template declaration. We look for hidden names
8233 because two friend declarations of the same template are the
8234 same. For example, in:
8236 struct A {
8237 template <typename> friend class F;
8238 };
8239 template <typename> struct B {
8240 template <typename> friend class F;
8241 };
8243 both F templates are the same. */
8247 /* But, if we don't find one, it might be because we're in a
8248 situation like this:
8250 template <class T>
8251 struct S {
8252 template <class U>
8253 friend struct S;
8254 };
8256 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8257 for `S<int>', not the TEMPLATE_DECL. */
8259 {
8262 }
8265 {
8266 /* The friend template has already been declared. Just
8267 check to see that the declarations match, and install any new
8268 default parameters. We must tsubst the default parameters,
8269 of course. We only need the innermost template parameters
8270 because that is all that redeclare_class_template will look
8271 at. */
8274 {
8275 tree parms;
8276 location_t saved_input_location;
8285 }
8288 }
8289 else
8290 {
8291 /* The friend template has not already been declared. In this
8292 case, the instantiation of the template class will cause the
8293 injection of this template into the global scope. */
8298 /* The new TMPL is not an instantiation of anything, so we
8299 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
8300 the new type because that is supposed to be the corresponding
8301 template decl, i.e., TMPL. */
8308 /* Inject this template into the global scope. */
8310 }
8313 {
8316 else
8318 }
8321 }
8323 /* Returns zero if TYPE cannot be completed later due to circularity.
8324 Otherwise returns one. */
8326 static int
8328 {
8338 else
8340 }
8342 /* Apply any attributes which had to be deferred until instantiation
8343 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
8344 ARGS, COMPLAIN, IN_DECL are as tsubst. */
8346 static void
8349 {
8351 tree t;
8356 {
8360 }
8363 {
8367 }
8368 else
8372 {
8377 {
8380 {
8383 /* If the first attribute argument is an identifier, don't
8384 pass it through tsubst. Attributes like mode, format,
8385 cleanup and several target specific attributes expect it
8386 unmodified. */
8392 {
8393 tree chain
8395 in_decl,
8400 chain);
8401 }
8402 else
8408 }
8409 else
8411 }
8414 }
8415 }
8417 /* Perform (or defer) access check for typedefs that were referenced
8418 from within the template TMPL code.
8419 This is a subroutine of instantiate_decl and instantiate_class_template.
8420 TMPL is the template to consider and TARGS is the list of arguments of
8421 that template. */
8423 static void
8425 {
8426 location_t saved_location;
8439 {
8451 /* Make access check error messages point to the location
8452 of the use of the typedef. */
8456 tf_warning_or_error);
8457 }
8459 }
8461 static tree
8463 {
8465 tree typedecl;
8466 tree pbinfo;
8467 tree base_list;
8469 tree fn_context;
8478 /* Figure out which template is being instantiated. */
8482 /* Determine what specialization of the original template to
8483 instantiate. */
8486 {
8489 }
8491 {
8492 /* This TYPE is actually an instantiation of a partial
8493 specialization. We replace the innermost set of ARGS with
8494 the arguments appropriate for substitution. For example,
8495 given:
8497 template <class T> struct S {};
8498 template <class T> struct S<T*> {};
8500 and supposing that we are instantiating S<int*>, ARGS will
8501 presently be {int*} -- but we need {int}. */
8504 }
8505 else
8506 {
8509 }
8511 /* If the template we're instantiating is incomplete, then clearly
8512 there's nothing we can do. */
8516 /* If we've recursively instantiated too many templates, stop. */
8520 /* Now we're really doing the instantiation. Mark the type as in
8521 the process of being defined. */
8524 /* We may be in the middle of deferred access check. Disable
8525 it now. */
8531 /* Use #pragma pack from the template context. */
8537 /* Set the input location to the most specialized template definition.
8538 This is needed if tsubsting causes an error. */
8550 {
8553 /* Adjust visibility for template arguments. */
8555 }
8560 /* We should never instantiate a nested class before its enclosing
8561 class; we need to look up the nested class by name before we can
8562 instantiate it, and that lookup should instantiate the enclosing
8563 class. */
8569 {
8570 tree pbase_binfo;
8571 tree pushed_scope;
8574 /* We must enter the scope containing the type, as that is where
8575 the accessibility of types named in dependent bases are
8576 looked up from. */
8579 /* Substitute into each of the bases to determine the actual
8580 basetypes. */
8582 {
8583 tree base;
8589 {
8590 expanded_bases =
8597 }
8600 {
8602 /* Extract the already-expanded base class. */
8604 else
8605 /* Substitute to figure out the base class. */
8607 NULL_TREE);
8615 }
8616 }
8618 /* The list is now in reverse order; correct that. */
8623 }
8624 /* Now call xref_basetypes to set up all the base-class
8625 information. */
8633 /* Now that our base classes are set up, enter the scope of the
8634 class, so that name lookups into base classes, etc. will work
8635 correctly. This is precisely analogous to what we do in
8636 begin_class_definition when defining an ordinary non-template
8637 class, except we also need to push the enclosing classes. */
8640 /* Now members are processed in the order of declaration. */
8643 {
8647 {
8649 {
8650 /* Build new CLASSTYPE_NESTED_UTDS. */
8652 tree newtag;
8658 /* If the member is a class template, then -- even after
8659 substitution -- there may be dependent types in the
8660 template argument list for the class. We increment
8661 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
8662 that function will assume that no types are dependent
8663 when outside of a template. */
8673 {
8677 /* Unfortunately, lookup_template_class sets
8678 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
8679 instantiation (i.e., for the type of a member
8680 template class nested within a template class.)
8681 This behavior is required for
8682 maybe_process_partial_specialization to work
8683 correctly, but is not accurate in this case;
8684 the TAG is not an instantiation of anything.
8685 (The corresponding TEMPLATE_DECL is an
8686 instantiation, but the TYPE is not.) */
8689 /* Now, we call pushtag to put this NEWTAG into the scope of
8690 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
8691 pushtag calling push_template_decl. We don't have to do
8692 this for enums because it will already have been done in
8693 tsubst_enum. */
8697 }
8698 }
8701 {
8702 /* Build new TYPE_METHODS. */
8703 tree r;
8712 /* Instantiate members marked with attribute used. */
8715 }
8716 else
8717 {
8718 /* Build new TYPE_FIELDS. */
8720 {
8721 tree condition;
8724 condition =
8734 }
8736 {
8737 tree r;
8739 /* The file and line for this declaration, to
8740 assist in error message reporting. Since we
8741 called push_tinst_level above, we don't need to
8742 restore these. */
8751 {
8752 /* In [temp.inst]:
8754 [t]he initialization (and any associated
8755 side-effects) of a static data member does
8756 not occur unless the static data member is
8757 itself used in a way that requires the
8758 definition of the static data member to
8759 exist.
8761 Therefore, we do not substitute into the
8762 initialized for the static data member here. */
8763 finish_static_data_member_decl
8769 /* Instantiate members marked with attribute used. */
8772 }
8774 {
8775 /* Determine whether R has a valid type and can be
8776 completed later. If R is invalid, then it is
8777 replaced by error_mark_node so that it will not be
8778 added to TYPE_FIELDS. */
8784 {
8787 }
8788 }
8790 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
8791 such a thing will already have been added to the field
8792 list by tsubst_enum in finish_member_declaration in the
8793 CLASSTYPE_NESTED_UTDS case above. */
8797 {
8800 }
8801 }
8802 }
8803 }
8804 else
8805 {
8808 {
8809 /* Build new CLASSTYPE_FRIEND_CLASSES. */
8815 {
8816 /* template <class T> friend class C; */
8819 }
8821 {
8822 /* template <class T> friend class C::D; */
8828 }
8831 {
8832 /* This could be either
8834 friend class T::C;
8836 when dependent_type_p is false or
8838 template <class U> friend class T::C;
8840 otherwise. */
8843 /* Bump processing_template_decl for correct
8844 dependent_type_p calculation. */
8849 }
8852 {
8853 /* friend class C;
8855 where C hasn't been declared yet. Let's lookup name
8856 from namespace scope directly, bypassing any name that
8857 come from dependent base class. */
8860 /* The call to xref_tag_from_type does injection for friend
8861 classes. */
8863 friend_type =
8867 }
8869 /* friend class C<T>; */
8872 /* Otherwise it's
8874 friend class C;
8876 where C is already declared or
8878 friend class C<int>;
8880 We don't have to do anything in these cases. */
8883 /* Trick make_friend_class into realizing that the friend
8884 we're adding is a template, not an ordinary class. It's
8885 important that we use make_friend_class since it will
8886 perform some error-checking and output cross-reference
8887 information. */
8895 }
8896 else
8897 {
8898 /* Build new DECL_FRIENDLIST. */
8899 tree r;
8901 /* The file and line for this declaration, to
8902 assist in error message reporting. Since we
8903 called push_tinst_level above, we don't need to
8904 restore these. */
8908 {
8911 }
8916 {
8919 }
8920 }
8921 }
8922 }
8925 {
8928 {
8937 }
8938 else
8940 }
8942 /* Set the file and line number information to whatever is given for
8943 the class itself. This puts error messages involving generated
8944 implicit functions at a predictable point, and the same point
8945 that would be used for non-template classes. */
8952 /* We don't instantiate default arguments for member functions. 14.7.1:
8954 The implicit instantiation of a class template specialization causes
8955 the implicit instantiation of the declarations, but not of the
8956 definitions or default arguments, of the class member functions,
8957 member classes, static data members and member templates.... */
8959 /* Some typedefs referenced from within the template code need to be access
8960 checked at template instantiation time, i.e now. These types were
8961 added to the template at parsing time. Let's get those and perform
8962 the access checks then. */
8972 /* The vtable for a template class can be emitted in any translation
8973 unit in which the class is instantiated. When there is no key
8974 method, however, finish_struct_1 will already have added TYPE to
8975 the keyed_classes list. */
8980 }
8982 /* Wrapper for instantiate_class_template_1. */
8984 tree
8986 {
8987 tree ret;
8992 }
8994 static tree
8996 {
8997 tree r;
9003 else
9004 {
9011 /* Preserve the raw-reference nature of T. */
9015 }
9017 }
9019 /* Given a function parameter pack TMPL_PARM and some function parameters
9020 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
9021 and set *SPEC_P to point at the next point in the list. */
9023 static tree
9025 {
9026 /* Collect all of the extra "packed" parameters into an
9027 argument pack. */
9028 tree parmvec;
9029 tree parmtypevec;
9040 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
9045 {
9048 }
9050 /* Build the argument packs. */
9057 }
9059 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9060 NONTYPE_ARGUMENT_PACK. */
9062 static tree
9064 {
9066 }
9068 /* Substitute ARGS into T, which is an pack expansion
9069 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
9070 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
9071 (if only a partial substitution could be performed) or
9072 ERROR_MARK_NODE if there was an error. */
9073 tree
9075 tree in_decl)
9076 {
9077 tree pattern;
9083 tree result;
9091 /* Add in any args remembered from an earlier partial instantiation. */
9096 /* Determine the argument packs that will instantiate the parameter
9097 packs used in the expansion expression. While we're at it,
9098 compute the number of arguments to be expanded and make sure it
9099 is consistent. */
9102 {
9109 {
9113 else
9116 }
9118 {
9121 else
9122 {
9123 /* We can't rely on local_specializations for a parameter
9124 name used later in a function declaration (such as in a
9125 late-specified return type). Even if it exists, it might
9126 have the wrong value for a recursive call. Just make a
9127 dummy decl, since it's only used for its type. */
9130 /* Partial instantiation of the parm_pack, we can't build
9131 up an argument pack yet. */
9133 else
9136 }
9137 }
9138 else
9139 {
9145 }
9152 /* This can only happen if we forget to expand an argument
9153 pack somewhere else. Just return an error, silently. */
9154 {
9158 }
9161 /* The argument pack that the parameter maps to is just an
9162 expansion of the parameter itself, such as one would find
9163 in the implicit typedef of a class inside the class itself.
9164 Consider this parameter "unsubstituted", so that we will
9165 maintain the outer pack expansion. */
9169 {
9173 /* Don't bother trying to do a partial substitution with
9174 incomplete packs; we'll try again after deduction. */
9181 {
9187 pattern);
9188 else
9191 pattern);
9193 }
9199 else
9202 /* Keep track of the parameter packs and their corresponding
9203 argument packs. */
9206 }
9207 else
9208 {
9209 /* We can't substitute for this parameter pack. We use a flag as
9210 well as the missing_level counter because function parameter
9211 packs don't have a level. */
9215 }
9216 }
9218 /* We cannot expand this expansion expression, because we don't have
9219 all of the argument packs we need. */
9221 {
9223 {
9224 /* We got some full packs, but we can't substitute them in until we
9225 have values for all the packs. So remember these until then. */
9226 tree save_args;
9230 /* The call to add_to_template_args above assumes no overlap
9231 between saved args and new args, so prune away any fake
9232 args, i.e. those that satisfied arg_from_parm_pack_p above. */
9234 {
9240 }
9241 else
9245 }
9246 else
9247 {
9248 /* There were no real arguments, we're just replacing a parameter
9249 pack with another version of itself. Substitute into the
9250 pattern and return a PACK_EXPANSION_*. The caller will need to
9251 deal with that. */
9255 else
9258 }
9260 }
9262 /* We could not find any argument packs that work. */
9267 {
9268 /* We're in a late-specified return type, so create our own local
9269 specializations map; the current map is either NULL or (in the
9270 case of recursive unification) might have bindings that we don't
9271 want to use or alter. */
9274 }
9276 /* For each argument in each argument pack, substitute into the
9277 pattern. */
9280 {
9281 /* For parameter pack, change the substitution of the parameter
9282 pack to the ith argument in its argument pack, then expand
9283 the pattern. */
9285 {
9287 tree arg;
9289 /* Select the Ith argument from the pack. */
9291 {
9293 {
9298 }
9299 else
9301 }
9302 else
9303 {
9308 {
9311 /* Update the corresponding argument. */
9313 }
9314 else
9315 /* Re-use the ARGUMENT_PACK_SELECT. */
9317 }
9319 }
9321 /* Substitute into the PATTERN with the altered arguments. */
9326 else
9330 {
9333 }
9334 }
9336 /* Update ARGS to restore the substitution from parameter packs to
9337 their argument packs. */
9339 {
9344 else
9345 {
9349 /* Update the corresponding argument. */
9353 else
9355 }
9356 }
9359 {
9362 }
9365 }
9367 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
9368 TMPL. We do this using DECL_PARM_INDEX, which should work even with
9369 parameter packs; all parms generated from a function parameter pack will
9370 have the same DECL_PARM_INDEX. */
9372 tree
9374 {
9376 tree patparm;
9379 {
9385 }
9386 else
9387 {
9392 }
9395 }
9397 /* Substitute ARGS into the vector or list of template arguments T. */
9399 static tree
9401 {
9413 {
9415 tree new_arg;
9420 {
9421 /* Substitute into an expansion expression. */
9425 /* Add to the expanded length adjustment the number of
9426 expanded arguments. We subtract one from this
9427 measurement, because the argument pack expression
9428 itself is already counted as 1 in
9429 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
9430 the argument pack is empty. */
9432 }
9434 {
9435 /* Substitute into each of the arguments. */
9441 new_arg,
9455 }
9456 }
9457 else
9466 }
9471 /* Make space for the expanded arguments coming from template
9472 argument packs. */
9474 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
9475 arguments for a member template.
9476 In that case each TREE_VEC in ORIG_T represents a level of template
9477 arguments, and ORIG_T won't carry any non defaulted argument count.
9478 It will rather be the nested TREE_VECs that will carry one.
9479 In other words, ORIG_T carries a non defaulted argument count only
9480 if it doesn't contain any nested TREE_VEC. */
9482 {
9486 }
9488 {
9492 {
9495 /* Now expand the template argument pack "in place". */
9498 }
9499 else
9500 {
9502 out++;
9503 }
9504 }
9507 }
9509 /* Return the result of substituting ARGS into the template parameters
9510 given by PARMS. If there are m levels of ARGS and m + n levels of
9511 PARMS, then the result will contain n levels of PARMS. For
9512 example, if PARMS is `template <class T> template <class U>
9513 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
9514 result will be `template <int*, double, class V>'. */
9516 static tree
9518 {
9522 /* When substituting into a template, we must set
9523 PROCESSING_TEMPLATE_DECL as the template parameters may be
9524 dependent if they are based on one-another, and the dependency
9525 predicates are short-circuit outside of templates. */
9532 {
9533 tree new_vec =
9538 {
9539 tree tuple;
9551 }
9557 }
9562 }
9564 /* Return the result of substituting ARGS into one template parameter
9565 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
9566 parameter and which TREE_PURPOSE is the default argument of the
9567 template parameter. */
9569 static tree
9571 {
9592 }
9594 /* Substitute the ARGS into the indicated aggregate (or enumeration)
9595 type T. If T is not an aggregate or enumeration type, it is
9596 handled as if by tsubst. IN_DECL is as for tsubst. If
9597 ENTERING_SCOPE is nonzero, T is the context for a template which
9598 we are presently tsubst'ing. Return the substituted value. */
9600 static tree
9602 tree args,
9603 tsubst_flags_t complain,
9604 tree in_decl,
9606 {
9611 {
9616 /* Else fall through. */
9620 {
9621 tree argvec;
9622 tree context;
9623 tree r;
9627 /* In "sizeof(X<I>)" we need to evaluate "I". */
9633 /* First, determine the context for the type we are looking
9634 up. */
9637 {
9640 /* If context is a nested class inside a class template,
9641 it may still need to be instantiated (c++/33959). */
9643 }
9645 /* Then, figure out what arguments are appropriate for the
9646 type we are trying to find. For example, given:
9648 template <class T> struct S;
9649 template <class T, class U> void f(T, U) { S<U> su; }
9651 and supposing that we are instantiating f<int, double>,
9652 then our ARGS will be {int, double}, but, when looking up
9653 S we only want {double}. */
9658 else
9659 {
9663 }
9669 }
9670 else
9671 /* This is not a template type, so there's nothing to do. */
9676 }
9677 }
9679 /* Substitute into the default argument ARG (a default argument for
9680 FN), which has the indicated TYPE. */
9682 tree
9684 {
9689 /* This can happen in invalid code. */
9693 /* This default argument came from a template. Instantiate the
9694 default argument here, not in tsubst. In the case of
9695 something like:
9697 template <class T>
9698 struct S {
9699 static T t();
9700 void f(T = t());
9701 };
9703 we must be careful to do name lookup in the scope of S<T>,
9704 rather than in the current class. */
9706 /* The "this" pointer is not valid in a default argument. */
9708 {
9713 }
9716 /* The default argument expression may cause implicitly defined
9717 member functions to be synthesized, which will result in garbage
9718 collection. We must treat this situation as if we were within
9719 the body of function so as to avoid collecting live data on the
9720 stack. */
9728 /* Restore the "this" pointer. */
9730 {
9733 }
9739 /* Make sure the default argument is reasonable. */
9745 }
9747 /* Substitute into all the default arguments for FN. */
9749 static void
9751 {
9752 tree arg;
9753 tree tmpl_args;
9757 /* If this function is not yet instantiated, we certainly don't need
9758 its default arguments. */
9761 /* Don't do this again for clones. */
9766 arg;
9772 }
9774 /* Substitute the ARGS into the T, which is a _DECL. Return the
9775 result of the substitution. Issue error and warning messages under
9776 control of COMPLAIN. */
9778 static tree
9780 {
9781 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
9782 location_t saved_loc;
9787 /* Set the filename and linenumber to improve error-reporting. */
9792 {
9794 {
9795 /* We can get here when processing a member function template,
9796 member class template, or template template parameter. */
9798 tree spec;
9799 tree tmpl_args;
9800 tree full_args;
9803 {
9804 /* Template template parameter is treated here. */
9817 complain);
9820 }
9822 /* We might already have an instance of this template.
9823 The ARGS are for the surrounding class type, so the
9824 full args contain the tsubst'd args for the context,
9825 plus the innermost args from the template decl. */
9829 /* Because this is a template, the arguments will still be
9830 dependent, even after substitution. If
9831 PROCESSING_TEMPLATE_DECL is not set, the dependency
9832 predicates will short-circuit. */
9840 /* If this is a default template template argument,
9841 tsubst might not have changed anything. */
9848 {
9851 }
9853 /* Make a new template decl. It will be similar to the
9854 original, but will record the current template arguments.
9855 We also create a new function declaration, which is just
9856 like the old one, but points to this new template, rather
9857 than the old one. */
9866 {
9867 tree new_type;
9879 }
9880 else
9881 {
9882 tree new_decl;
9894 }
9900 /* The template parameters for this new template are all the
9901 template parameters for the old template, except the
9902 outermost level of parameters. */
9905 complain);
9911 /* Record this non-type partial instantiation. */
9915 }
9919 {
9920 tree ctx;
9923 tree gen_tmpl;
9924 tree type;
9929 /* Nobody should be tsubst'ing into non-template functions. */
9933 {
9934 tree spec;
9937 /* If T is not dependent, just return it. We have to
9938 increment PROCESSING_TEMPLATE_DECL because
9939 value_dependent_expression_p assumes that nothing is
9940 dependent when PROCESSING_TEMPLATE_DECL is zero. */
9947 /* Calculate the most general template of which R is a
9948 specialization, and the complete set of arguments used to
9949 specialize R. */
9952 (DECL_TEMPLATE_RESULT
9958 /* Check to see if we already have this specialization. */
9963 {
9966 }
9968 /* We can see more levels of arguments than parameters if
9969 there was a specialization of a member template, like
9970 this:
9972 template <class T> struct S { template <class U> void f(); }
9973 template <> template <class U> void S<int>::f(U);
9975 Here, we'll be substituting into the specialization,
9976 because that's where we can find the code we actually
9977 want to generate, but we'll have enough arguments for
9978 the most general template.
9980 We also deal with the peculiar case:
9982 template <class T> struct S {
9983 template <class U> friend void f();
9984 };
9985 template <class U> void f() {}
9986 template S<int>;
9987 template void f<double>();
9989 Here, the ARGS for the instantiation of will be {int,
9990 double}. But, we only need as many ARGS as there are
9991 levels of template parameters in CODE_PATTERN. We are
9992 careful not to get fooled into reducing the ARGS in
9993 situations like:
9995 template <class T> struct S { template <class U> void f(U); }
9996 template <class T> template <> void S<T>::f(int) {}
9998 which we can spot because the pattern will be a
9999 specialization in this case. */
10001 parms_depth =
10006 }
10007 else
10008 {
10009 /* This special case arises when we have something like this:
10011 template <class T> struct S {
10012 friend void f<int>(int, double);
10013 };
10015 Here, the DECL_TI_TEMPLATE for the friend declaration
10016 will be an IDENTIFIER_NODE. We are being called from
10017 tsubst_friend_function, and we want only to create a
10018 new decl (R) with appropriate types so that we can call
10019 determine_specialization. */
10021 }
10024 {
10027 else
10031 }
10032 else
10033 {
10036 }
10041 /* If we hit excessive deduction depth, the type is bogus even if
10042 it isn't error_mark_node, so don't build a decl. */
10046 /* We do NOT check for matching decls pushed separately at this
10047 point, as they may not represent instantiations of this
10048 template, and in any case are considered separate under the
10049 discrete model. */
10053 /* Clear out the mangled name and RTL for the instantiation. */
10056 /* Leave DECL_INITIAL set on deleted instantiations. */
10062 /* Type-conversion operator. Reconstruct the name, in
10063 case it's the name of one of the template's parameters. */
10073 /* If this is an instantiation of a function with internal
10074 linkage, we already know what object file linkage will be
10075 assigned to the instantiation. */
10084 /* We'll re-clone as appropriate in instantiate_template. */
10087 /* If we aren't complaining now, return on error before we register
10088 the specialization so that we'll complain eventually. */
10094 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
10095 this in the special friend case mentioned above where
10096 GEN_TMPL is NULL. */
10098 {
10104 /* We're not supposed to instantiate default arguments
10105 until they are called, for a template. But, for a
10106 declaration like:
10108 template <class T> void f ()
10109 { extern void g(int i = T()); }
10111 we should do the substitution when the template is
10112 instantiated. We handle the member function case in
10113 instantiate_class_template since the default arguments
10114 might refer to other members of the class. */
10119 }
10120 else
10123 /* Copy the list of befriending classes. */
10127 {
10131 in_decl);
10132 }
10135 {
10139 /* If this is an instantiation of a member template, clone it.
10140 If it isn't, that'll be handled by
10141 clone_constructors_and_destructors. */
10144 }
10155 /* Possibly limit visibility based on template args. */
10158 {
10162 }
10170 }
10174 {
10182 {
10183 /* If there is a local specialization that isn't a
10184 parameter pack, it means that we're doing a "simple"
10185 substitution from inside tsubst_pack_expansion. Just
10186 return the local specialization (which will be a single
10187 parm). */
10194 /* Expand the TYPE_PACK_EXPANSION that provides the types for
10195 the parameters in this function parameter pack. */
10199 {
10202 /* Zero-length parameter packs are boring. Just substitute
10203 into the chain. */
10207 }
10208 else
10209 {
10210 /* All we did was update the type. Make a note of that. */
10213 }
10214 }
10216 /* Loop through all of the parameter's we'll build. When T is
10217 a function parameter pack, LEN is the number of expanded
10218 types in EXPANDED_TYPES; otherwise, LEN is 1. */
10221 {
10228 /* We're on the Ith parameter of the function parameter
10229 pack. */
10230 {
10231 /* An argument of a function parameter pack is not a parameter
10232 pack. */
10235 /* Get the Ith type. */
10239 /* Rename the parameter to include the index. */
10242 }
10244 /* We're dealing with a normal parameter. */
10252 {
10255 else
10258 }
10268 /* Keep track of the first new parameter we
10269 generate. That's what will be returned to the
10270 caller. */
10274 /* Build a proper chain of parameters when substituting
10275 into a function parameter pack. */
10278 }
10280 /* If cp_unevaluated_operand is set, we're just looking for a
10281 single dummy parameter, so don't keep going. */
10286 /* FIRST_R contains the start of the chain we've built. */
10288 }
10292 {
10293 tree type;
10303 /* For bit-fields, DECL_INITIAL gives the number of bits. For
10304 non-bit-fields DECL_INITIAL is a non-static data member
10305 initializer, which gets deferred instantiation. */
10311 {
10312 /* Set up DECL_TEMPLATE_INFO so that we can get at the
10313 NSDMI in perform_member_init. Still set DECL_INITIAL
10314 so that we know there is one. */
10319 }
10320 /* We don't have to set DECL_CONTEXT here; it is set by
10321 finish_member_declaration. */
10328 }
10332 /* We reach here only for member using decls. We also need to check
10333 uses_template_parms because DECL_DEPENDENT_P is not set for a
10334 using-declaration that designates a member of the current
10335 instantiation (c++/53549). */
10338 {
10339 r = do_class_using_decl
10344 else
10345 {
10348 }
10349 }
10350 else
10351 {
10354 }
10359 {
10362 tree spec;
10364 tree ctx;
10370 {
10371 /* If this is the canonical decl, we don't have to
10372 mess with instantiations, and often we can't (for
10373 typename, template type parms and such). Note that
10374 TYPE_NAME is not correct for the above test if
10375 we've copied the type for a typedef. */
10381 }
10383 /* Check to see if we already have the specialization we
10384 need. */
10387 {
10388 /* T is a static data member or namespace-scope entity.
10389 We have to substitute into namespace-scope variables
10390 (even though such entities are never templates) because
10391 of cases like:
10393 template <class T> void f() { extern T t; }
10395 where the entity referenced is not known until
10396 instantiation time. */
10400 {
10402 complain,
10404 /* If CTX is unchanged, then T is in fact the
10405 specialization we want. That situation occurs when
10406 referencing a static data member within in its own
10407 class. We can use pointer equality, rather than
10408 same_type_p, because DECL_CONTEXT is always
10409 canonical... */
10412 /* ... unless T is a member template; in which
10413 case our caller can be willing to create a
10414 specialization of that template represented
10415 by T. */
10419 }
10422 {
10430 }
10431 }
10432 else
10433 {
10434 /* A local variable. */
10436 /* Subsequent calls to pushdecl will fill this in. */
10439 }
10440 /* If we already have the specialization we need, there is
10441 nothing more to do. */
10443 {
10446 }
10449 {
10450 /* Just use name lookup to find a member alias for an anonymous
10451 union, but then add it to the hash table. */
10456 }
10458 /* Create a new node for the specialization we need. */
10461 {
10464 else
10471 }
10473 {
10474 /* Even if the original location is out of scope, the
10475 newly substituted one is not. */
10482 {
10483 /* It may seem that this case cannot occur, since:
10485 typedef void f();
10486 void g() { f x; }
10488 declares a function, not a variable. However:
10490 typedef void f();
10491 template <typename T> void g() { T t; }
10492 template void g<f>();
10494 is an attempt to declare a variable with function
10495 type. */
10497 /* R is not yet sufficiently initialized, so we
10498 just use its name. */
10501 }
10503 /* Wait until cp_finish_decl to set this again, to handle
10504 circular dependency (template/instantiate6.C). */
10509 {
10514 {
10517 }
10519 }
10520 }
10526 /* Clear out the mangled name and RTL for the instantiation. */
10530 /* The initializer must not be expanded until it is required;
10531 see [temp.inst]. */
10537 {
10538 /* Possibly limit visibility based on template args. */
10541 {
10545 }
10547 }
10550 {
10551 /* A static data member declaration is always marked
10552 external when it is declared in-class, even if an
10553 initializer is present. We mimic the non-template
10554 processing here. */
10560 }
10562 {
10563 /* We're substituting this var in a decltype outside of its
10564 scope, such as for a lambda return type. Don't add it to
10565 local_specializations, do perform auto deduction. */
10568 {
10569 tree init
10575 }
10576 }
10577 else
10586 /* Preserve a typedef that names a type. */
10588 {
10591 }
10594 }
10599 }
10600 #undef RETURN
10602 out:
10603 /* Restore the file and line information. */
10607 }
10609 /* Substitute into the ARG_TYPES of a function type.
10610 If END is a TREE_CHAIN, leave it and any following types
10611 un-substituted. */
10613 static tree
10615 tree args,
10616 tree end,
10617 tsubst_flags_t complain,
10618 tree in_decl)
10619 {
10620 tree remaining_arg_types;
10624 tree default_arg;
10635 {
10636 /* For a pack expansion, perform substitution on the
10637 entire expression. Later on, we'll handle the arguments
10638 one-by-one. */
10643 /* So that we'll spin through the parameters, one by one. */
10645 else
10646 {
10647 /* We only partially substituted into the parameter
10648 pack. Our type is TYPE_PACK_EXPANSION. */
10651 }
10652 }
10665 {
10667 {
10671 }
10673 }
10675 /* Do array-to-pointer, function-to-pointer conversion, and ignore
10676 top-level qualifiers as required. */
10679 /* We do not substitute into default arguments here. The standard
10680 mandates that they be instantiated only when needed, which is
10681 done in build_over_call. */
10685 {
10686 /* We've instantiated a template before its default arguments
10687 have been parsed. This can happen for a nested template
10688 class, and is not an error unless we require the default
10689 argument in a call of this function. */
10690 remaining_arg_types =
10693 remaining_arg_types);
10694 }
10695 else
10696 remaining_arg_types =
10698 }
10701 }
10703 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
10704 *not* handle the exception-specification for FNTYPE, because the
10705 initial substitution of explicitly provided template parameters
10706 during argument deduction forbids substitution into the
10707 exception-specification:
10709 [temp.deduct]
10711 All references in the function type of the function template to the
10712 corresponding template parameters are replaced by the specified tem-
10713 plate argument values. If a substitution in a template parameter or
10714 in the function type of the function template results in an invalid
10715 type, type deduction fails. [Note: The equivalent substitution in
10716 exception specifications is done only when the function is instanti-
10717 ated, at which point a program is ill-formed if the substitution
10718 results in an invalid type.] */
10720 static tree
10722 tree args,
10723 tsubst_flags_t complain,
10724 tree in_decl)
10725 {
10726 tree return_type;
10727 tree arg_types;
10728 tree fntype;
10730 /* The TYPE_CONTEXT is not used for function/method types. */
10733 /* Substitute the return type. */
10737 /* The standard does not presently indicate that creation of a
10738 function type with an invalid return type is a deduction failure.
10739 However, that is clearly analogous to creating an array of "void"
10740 or a reference to a reference. This is core issue #486. */
10743 {
10745 {
10748 else
10750 }
10752 }
10754 /* Substitute the argument types. */
10760 /* Construct a new type node and return it. */
10762 {
10765 }
10766 else
10767 {
10770 {
10771 /* [temp.deduct]
10773 Type deduction may fail for any of the following
10774 reasons:
10776 -- Attempting to create "pointer to member of T" when T
10777 is not a class type. */
10780 r);
10782 }
10786 }
10790 }
10792 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
10793 ARGS into that specification, and return the substituted
10794 specification. If there is no specification, return NULL_TREE. */
10796 static tree
10798 tree args,
10799 tsubst_flags_t complain,
10800 tree in_decl,
10802 {
10803 tree specs;
10804 tree new_specs;
10809 {
10810 /* A noexcept-specifier. */
10815 {
10816 /* Defer instantiation of noexcept-specifiers to avoid
10817 excessive instantiations (c++/49107). */
10820 {
10821 /* We already partially instantiated this member template,
10822 so combine the new args with the old. */
10827 }
10828 else
10829 {
10832 }
10833 }
10834 else
10835 new_specs = tsubst_copy_and_build
10839 }
10841 {
10844 else
10846 {
10847 tree spec;
10852 {
10853 /* Expand the pack expansion type. */
10856 in_decl);
10862 else
10863 {
10864 /* We're substituting into a member template, so
10865 we got a TYPE_PACK_EXPANSION back. Add that
10866 expansion and move on. */
10870 expanded_specs,
10871 complain);
10874 }
10875 }
10878 {
10881 else
10886 complain);
10887 }
10890 }
10891 }
10893 }
10895 /* Take the tree structure T and replace template parameters used
10896 therein with the argument vector ARGS. IN_DECL is an associated
10897 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
10898 Issue error and warning messages under control of COMPLAIN. Note
10899 that we must be relatively non-tolerant of extensions here, in
10900 order to preserve conformance; if we allow substitutions that
10901 should not be allowed, we may allow argument deductions that should
10902 not succeed, and therefore report ambiguous overload situations
10903 where there are none. In theory, we could allow the substitution,
10904 but indicate that it should have failed, and allow our caller to
10905 make sure that the right thing happens, but we don't try to do this
10906 yet.
10908 This function is used for dealing with types, decls and the like;
10909 for expressions, use tsubst_expr or tsubst_copy. */
10911 tree
10913 {
10936 else
10941 /* Reuse typedefs. We need to do this to handle dependent attributes,
10942 such as attribute aligned. */
10945 {
10952 {
10953 /* DECL represents an alias template and we want to
10954 instantiate it. */
10958 }
10962 {
10966 }
10971 else
10972 /* The typedef is from a non-template context. */
10976 {
10978 r = cp_build_qualified_type_real
10982 }
10983 else
10984 /* We don't have an instantiation yet, so drop the typedef. */
10986 }
10999 {
11025 {
11031 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
11032 needed. */
11038 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
11039 with TREE_SIDE_EFFECTS that indicates this is not an integral
11040 constant expression. */
11043 {
11046 }
11049 }
11055 {
11068 {
11072 /* See through ARGUMENT_PACK_SELECT arguments. */
11074 }
11079 {
11081 /* If ARG is an argument pack, we don't actually want to
11082 perform a substitution here, because substitutions
11083 for argument packs are only done
11084 element-by-element. We can get to this point when
11085 substituting the type of a non-type template
11086 parameter pack, when that type actually contains
11087 template parameter packs from an outer template, e.g.,
11089 template<typename... Types> struct A {
11090 template<Types... Values> struct B { };
11091 }; */
11095 {
11101 return cp_build_qualified_type_real
11103 }
11105 {
11106 /* We are processing a type constructed from a
11107 template template parameter. */
11118 /* Consider this code:
11120 template <template <class> class Template>
11121 struct Internal {
11122 template <class Arg> using Bind = Template<Arg>;
11123 };
11125 template <template <class> class Template, class Arg>
11126 using Instantiate = Template<Arg>; //#0
11128 template <template <class> class Template,
11129 class Argument>
11130 using Bind =
11131 Instantiate<Internal<Template>::template Bind,
11132 Argument>; //#1
11134 When #1 is parsed, the
11135 BOUND_TEMPLATE_TEMPLATE_PARM representing the
11136 parameter `Template' in #0 matches the
11137 UNBOUND_CLASS_TEMPLATE representing the argument
11138 `Internal<Template>::template Bind'; We then want
11139 to assemble the type `Bind<Argument>' that can't
11140 be fully created right now, because
11141 `Internal<Template>' not being complete, the Bind
11142 template cannot be looked up in that context. So
11143 we need to "store" `Bind<Argument>' for later
11144 when the context of Bind becomes complete. Let's
11145 store that in a TYPENAME_TYPE. */
11149 argvec),
11150 typename_type,
11151 complain);
11153 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
11154 are resolving nested-types in the signature of a
11155 member function templates. Otherwise ARG is a
11156 TEMPLATE_DECL and is the real template to be
11157 instantiated. */
11165 complain);
11166 return cp_build_qualified_type_real
11168 }
11169 else
11170 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
11172 }
11175 /* This can happen during the attempted tsubst'ing in
11176 unify. This means that we don't yet have any information
11177 about the template parameter in question. */
11180 /* Early in template argument deduction substitution, we don't
11181 want to reduce the level of 'auto', or it will be confused
11182 with a normal template parm in subsequent deduction. */
11186 /* If we get here, we must have been looking at a parm for a
11187 more deeply nested template. Make a new version of this
11188 template parameter, but with a lower level. */
11190 {
11195 {
11197 r = cp_build_qualified_type_real
11201 }
11202 else
11203 {
11214 /* We have reduced the level of the template
11215 template parameter, but not the levels of its
11216 template parameters, so canonical_type_parameter
11217 will not be able to find the canonical template
11218 template parameter for this level. Thus, we
11219 require structural equality checking to compare
11220 TEMPLATE_TEMPLATE_PARMs. */
11224 else
11228 {
11236 }
11237 }
11246 }
11249 }
11252 {
11260 {
11264 }
11267 {
11271 }
11274 {
11278 }
11284 }
11287 /* We should never be tsubsting a binfo. */
11291 /* A vector of template arguments. */
11297 {
11301 /* [temp.deduct]
11303 Type deduction may fail for any of the following
11304 reasons:
11306 -- Attempting to create a pointer to reference type.
11307 -- Attempting to create a reference to a reference type or
11308 a reference to void.
11310 Core issue 106 says that creating a reference to a reference
11311 during instantiation is no longer a cause for failure. We
11312 only enforce this check in strict C++98 mode. */
11316 {
11319 /* We keep track of the last time we issued this error
11320 message to avoid spewing a ton of messages during a
11321 single bad template instantiation. */
11324 {
11329 else
11332 }
11335 }
11337 {
11341 }
11343 /* In C++0x, during template argument substitution, when there is an
11344 attempt to create a reference to a reference type, reference
11345 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
11347 "If a template-argument for a template-parameter T names a type
11348 that is a reference to a type A, an attempt to create the type
11349 'lvalue reference to cv T' creates the type 'lvalue reference to
11350 A,' while an attempt to create the type type rvalue reference to
11351 cv T' creates the type T"
11352 */
11353 r = cp_build_reference_type
11356 else
11361 /* Will this ever be needed for TYPE_..._TO values? */
11365 }
11367 {
11370 {
11371 /* [temp.deduct]
11373 Type deduction may fail for any of the following
11374 reasons:
11376 -- Attempting to create "pointer to member of T" when T
11377 is not a class type. */
11381 }
11383 {
11387 }
11389 {
11393 }
11396 {
11397 /* The type of the implicit object parameter gets its
11398 cv-qualifiers from the FUNCTION_TYPE. */
11399 tree memptr;
11403 complain);
11404 }
11405 else
11408 complain);
11409 }
11412 {
11413 tree fntype;
11414 tree specs;
11419 /* Substitute the exception specification. */
11427 }
11429 {
11434 /* As an optimization, we avoid regenerating the array type if
11435 it will obviously be the same as T. */
11439 /* These checks should match the ones in grokdeclarator.
11441 [temp.deduct]
11443 The deduction may fail for any of the following reasons:
11445 -- Attempting to create an array with an element type that
11446 is void, a function type, or a reference type, or [DR337]
11447 an abstract class type. */
11451 {
11455 }
11457 {
11460 type);
11462 }
11467 {
11470 }
11473 }
11476 {
11486 {
11490 }
11492 {
11493 /* Normally, make_typename_type does not require that the CTX
11494 have complete type in order to allow things like:
11496 template <class T> struct S { typename S<T>::X Y; };
11498 But, such constructs have already been resolved by this
11499 point, so here CTX really should have complete type, unless
11500 it's a partial instantiation. */
11503 {
11507 }
11508 }
11515 {
11518 }
11521 {
11523 {
11527 else
11529 }
11531 {
11535 else
11537 }
11538 }
11540 return cp_build_qualified_type_real
11542 }
11545 {
11557 }
11560 {
11561 tree type;
11577 complain);
11578 }
11581 {
11582 tree type;
11598 else
11599 type = finish_decltype_type
11604 complain);
11605 }
11608 {
11612 }
11616 {
11618 tree packed_out =
11620 args,
11621 complain,
11622 in_decl);
11625 /* For template nontype argument packs, also substitute into
11626 the type. */
11631 }
11646 /* We should use one of the expression tsubsts for these codes. */
11652 }
11653 }
11655 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
11656 type of the expression on the left-hand side of the "." or "->"
11657 operator. */
11659 static tree
11662 {
11663 tree name;
11664 tree qualifying_scope;
11665 tree fns;
11666 tree optype;
11671 /* A baselink indicates a function from a base class. Both the
11672 BASELINK_ACCESS_BINFO and the base class referenced may
11673 indicate bases of the template class, rather than the
11674 instantiated class. In addition, lookups that were not
11675 ambiguous before may be ambiguous now. Therefore, we perform
11676 the lookup again. */
11683 {
11690 }
11698 /* If lookup found a single function, mark it as used at this
11699 point. (If it lookup found multiple functions the one selected
11700 later by overload resolution will be marked as used at that
11701 point.) */
11707 /* Add back the template arguments, if present. */
11712 template_args);
11713 /* Update the conversion operator type. */
11721 qualifying_scope,
11722 object_type);
11724 }
11726 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
11727 true if the qualified-id will be a postfix-expression in-and-of
11728 itself; false if more of the postfix-expression follows the
11729 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
11730 of "&". */
11732 static tree
11736 {
11737 tree expr;
11738 tree scope;
11739 tree name;
11741 tree template_args;
11746 /* Figure out what name to look up. */
11749 {
11757 }
11758 else
11759 {
11762 }
11764 /* Substitute into the qualifying scope. When there are no ARGS, we
11765 are just trying to simplify a non-dependent expression. In that
11766 case the qualifying scope may be dependent, and, in any case,
11767 substituting will not help. */
11770 {
11773 }
11774 else
11778 {
11783 }
11786 {
11788 {
11789 /* A BIT_NOT_EXPR is used to represent a destructor. */
11791 {
11795 }
11796 else
11799 }
11800 else
11804 {
11806 {
11810 }
11812 }
11813 }
11816 {
11818 scope);
11819 /* Remember that there was a reference to this entity. */
11821 }
11824 {
11830 }
11839 {
11840 expr = (adjust_result_of_qualified_name_lookup
11842 expr = (finish_qualified_id_expr
11846 }
11848 /* Expressions do not generally have reference type. */
11850 /* However, if we're about to form a pointer-to-member, we just
11851 want the referenced member referenced. */
11856 }
11858 /* Like tsubst, but deals with expressions. This function just replaces
11859 template parms; to finish processing the resultant expression, use
11860 tsubst_copy_and_build or tsubst_expr. */
11862 static tree
11864 {
11866 tree r;
11874 {
11879 {
11880 /* We get here for a use of 'this' in an NSDMI. */
11886 /* This can happen for a parameter name used later in a function
11887 declaration (such as in a late-specified return type). Just
11888 make a dummy decl, since it's only used for its type. */
11891 /* Give it the template pattern as its context; its true context
11892 hasn't been instantiated yet and this is good enough for
11893 mangling. */
11895 }
11903 {
11904 tree enum_type;
11905 tree v;
11909 /* There is no need to substitute into namespace-scope
11910 enumerators. */
11913 /* If ARGS is NULL, then T is known to be non-dependent. */
11917 /* Unfortunately, we cannot just call lookup_name here.
11918 Consider:
11920 template <int I> int f() {
11921 enum E { a = I };
11922 struct S { void g() { E e = a; } };
11923 };
11925 When we instantiate f<7>::S::g(), say, lookup_name is not
11926 clever enough to find f<7>::a. */
11927 enum_type
11937 /* We didn't find the name. That should never happen; if
11938 name-lookup found it during preliminary parsing, we
11939 should find it again here during instantiation. */
11941 }
11946 {
11947 tree ctx;
11952 {
11955 {
11959 }
11961 }
11962 }
11978 /* An OVERLOAD will always be a non-dependent overload set; an
11979 overload set from function scope will just be represented with an
11980 IDENTIFIER_NODE, and from class scope with a BASELINK. */
11995 {
11996 /* Template template argument like the following example need
11997 special treatment:
11999 template <template <class> class TT> struct C {};
12000 template <class T> struct D {
12001 template <class U> struct E {};
12002 C<E> c; // #1
12003 };
12004 D<int> d; // #2
12006 We are processing the template argument `E' in #1 for
12007 the template instantiation #2. Originally, `E' is a
12008 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
12009 have to substitute this with one having context `D<int>'. */
12013 }
12014 else
12015 /* Ordinary template template argument. */
12026 return build1
12032 {
12034 tree expanded;
12039 /* We only want to compute the number of arguments. */
12054 {
12061 else
12064 }
12065 else
12067 }
12068 /* Fall through */
12083 return build1
12088 {
12089 tree object;
12090 tree name;
12095 {
12099 }
12102 {
12112 }
12117 in_decl);
12118 else
12121 }
12159 return build_nt
12172 return build_nt
12179 {
12187 }
12192 {
12193 r = build_nt
12199 }
12202 {
12203 r = build_nt
12209 }
12212 {
12213 r = build_nt
12219 }
12222 {
12223 /* Substituted template arguments */
12232 }
12235 {
12255 }
12280 {
12283 }
12284 else
12288 /* This is handled by tsubst_copy_and_build. */
12294 in_decl),
12298 /* We shouldn't have built any of these during initial template
12299 generation. Instead, they should be built during instantiation
12300 in response to the saved STMT_IS_FULL_EXPR_P setting. */
12304 r = build2
12324 {
12325 /* Instantiate any typedefs in the type. */
12330 }
12333 /* These can sometimes show up in a partial instantiation, but never
12334 involve template parms. */
12339 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
12342 }
12343 }
12345 /* Like tsubst_copy, but specifically for OpenMP clauses. */
12347 static tree
12349 tree in_decl)
12350 {
12354 {
12360 {
12363 {
12369 }
12370 /* FALLTHRU */
12394 }
12395 }
12398 }
12400 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
12402 static tree
12404 tree in_decl)
12405 {
12406 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
12426 {
12429 else
12430 {
12434 }
12435 }
12440 #undef RECUR
12441 }
12443 /* Substitute one OMP_FOR iterator. */
12445 static void
12450 {
12451 #define RECUR(NODE) \
12452 tsubst_expr ((NODE), args, complain, in_decl, \
12453 integral_constant_expression_p)
12461 /* Do this before substituting into decl to handle 'auto'. */
12466 {
12470 }
12475 {
12482 complain);
12483 else
12490 }
12493 {
12494 tree c;
12496 {
12507 }
12509 {
12514 {
12517 }
12518 }
12519 }
12525 else
12529 {
12540 {
12547 }
12548 else
12554 {
12560 }
12564 {
12571 }
12572 else
12578 }
12584 #undef RECUR
12585 }
12587 /* Like tsubst_copy for expressions, etc. but also does semantic
12588 processing. */
12590 static tree
12593 {
12594 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12595 #define RECUR(NODE) \
12596 tsubst_expr ((NODE), args, complain, in_decl, \
12597 integral_constant_expression_p)
12600 tree r;
12601 location_t loc;
12613 {
12615 {
12616 tree_stmt_iterator i;
12620 }
12635 else
12644 {
12646 tree init;
12652 {
12655 tree decl;
12663 else
12665 }
12666 else
12667 {
12671 {
12672 /* By marking the declaration as instantiated, we avoid
12673 trying to instantiate it. Since instantiate_decl can't
12674 handle local variables, and since we've already done
12675 all that needs to be done, that's the right thing to
12676 do. */
12681 /* Anonymous aggregates are a special case. */
12684 {
12687 }
12690 else
12691 {
12696 {
12697 /* For __PRETTY_FUNCTION__ we have to adjust the
12698 initializer. */
12702 }
12703 else
12704 {
12708 {
12709 /* If we had an initializer but it
12710 instantiated to nothing,
12711 value-initialize the object. This will
12712 only occur when the initializer was a
12713 pack expansion where the parameter packs
12714 used in that expansion were of length
12715 zero. */
12717 complain);
12720 }
12721 else
12723 }
12726 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
12729 }
12730 }
12731 }
12734 }
12749 {
12759 }
12786 {
12790 }
12798 else
12806 else
12833 {
12835 tree label;
12840 }
12846 /* Computed goto's must be tsubst'd into. On the other hand,
12847 non-computed gotos must not be; the identifier in question
12848 will have no binding. */
12850 else
12856 tmp = finish_asm_stmt
12863 {
12868 }
12873 {
12878 }
12879 else
12880 {
12885 else
12892 else
12898 else
12900 }
12904 {
12908 {
12910 /* Prevent instantiate_decl from trying to instantiate
12911 this variable. We've already done all that needs to be
12912 done. */
12915 }
12920 }
12926 {
12927 /* Local classes are not independent templates; they are
12928 instantiated along with their containing function. And this
12929 way we don't have to deal with pushing out of one local class
12930 to instantiate a member of another local class. */
12931 tree fn;
12932 /* Closures are handled by the LAMBDA_EXPR. */
12938 }
12942 {
12943 tree condition;
12946 condition =
12948 args,
12957 }
12978 {
12995 integral_constant_expression_p);
13009 }
13041 {
13046 {
13049 }
13054 }
13055 else
13056 {
13063 {
13066 }
13069 {
13074 {
13077 }
13081 }
13082 else
13083 {
13087 }
13089 }
13093 {
13099 {
13103 {
13108 }
13112 }
13113 else
13114 {
13119 }
13120 }
13138 /* If the first operand was a statement, we're done with it. */
13142 complain));
13149 integral_constant_expression_p));
13150 }
13153 out:
13156 #undef RECUR
13157 #undef RETURN
13158 }
13160 /* T is a postfix-expression that is not being used in a function
13161 call. Return the substituted version of T. */
13163 static tree
13165 tsubst_flags_t complain,
13166 tree in_decl)
13167 {
13171 else
13177 }
13179 /* Like tsubst but deals with expressions and performs semantic
13180 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
13182 tree
13184 tree args,
13185 tsubst_flags_t complain,
13186 tree in_decl,
13189 {
13190 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
13191 #define RECUR(NODE) \
13192 tsubst_copy_and_build (NODE, args, complain, in_decl, \
13194 integral_constant_expression_p)
13197 location_t loc;
13207 {
13210 /* Fall through. */
13212 {
13213 tree decl;
13214 cp_id_kind idk;
13219 {
13222 }
13224 /* Look up the name. */
13227 /* By convention, expressions use ERROR_MARK_NODE to indicate
13228 failure, not NULL_TREE. */
13234 integral_constant_expression_p,
13242 input_location);
13246 {
13250 }
13252 }
13255 {
13256 tree object;
13264 {
13267 }
13268 else
13275 else
13277 }
13280 {
13284 {
13285 /* A type conversion to reference type will be enclosed in
13286 such an indirect ref, but the substitution of the cast
13287 will have also added such an indirect ref. */
13290 }
13291 else
13294 }
13302 {
13309 flags));
13310 }
13323 {
13324 tree type;
13330 {
13335 }
13341 {
13359 }
13363 }
13395 else
13397 in_decl);
13431 {
13432 tree r;
13436 r = build_x_binary_op
13440 ? ERROR_MARK
13444 ? ERROR_MARK
13447 complain);
13454 }
13468 /* Fall through */
13473 {
13474 /* When there are no ARGS, we are trying to evaluate a
13475 non-dependent expression from the parser. Trying to do
13476 the substitutions may not work. */
13479 }
13480 else
13481 {
13489 }
13493 else
13498 {
13508 }
13522 {
13523 tree r = build_x_modify_expr
13528 complain);
13529 /* TREE_NO_WARNING must be set if either the expression was
13530 parenthesized or it uses an operator such as >>= rather
13531 than plain assignment. In the former case, it was already
13532 set and must be copied. In the latter case,
13533 build_x_modify_expr sets it and it must not be reset
13534 here. */
13538 }
13543 /* Remember that there was a reference to this entity. */
13549 {
13554 tree ret;
13558 else
13559 {
13563 }
13565 /* If there was an initializer in the original tree, but it
13566 instantiated to an empty list, then we should pass a
13567 non-NULL empty vector to tell build_new that it was an
13568 empty initializer() rather than no initializer. This can
13569 only happen when the initializer is a pack expansion whose
13570 parameter packs are of length zero. */
13573 else
13574 {
13578 else
13579 {
13582 }
13583 }
13590 complain);
13598 }
13606 complain));
13612 complain));
13615 {
13616 tree function;
13621 tree ret;
13624 /* When we parsed the expression, we determined whether or
13625 not Koenig lookup should be performed. */
13628 {
13633 }
13635 {
13636 /* Do nothing; calling tsubst_copy_and_build on an identifier
13637 would incorrectly perform unqualified lookup again.
13639 Note that we can also have an IDENTIFIER_NODE if the earlier
13640 unqualified lookup found a member function; in that case
13641 koenig_p will be false and we do want to do the lookup
13642 again to find the instantiated member function.
13644 FIXME but doing that causes c++/15272, so we need to stop
13645 using IDENTIFIER_NODE in that situation. */
13647 }
13648 else
13649 {
13651 {
13657 }
13658 else
13662 in_decl,
13664 integral_constant_expression_p);
13668 }
13673 {
13679 else
13680 {
13681 /* Expand the pack expansion and push each entry onto
13682 CALL_ARGS. */
13685 {
13690 {
13695 }
13696 }
13697 else
13698 {
13699 /* A partial substitution. Add one entry. */
13701 }
13702 }
13703 }
13705 /* We do not perform argument-dependent lookup if normal
13706 lookup finds a non-function, in accordance with the
13707 expected resolution of DR 218. */
13710 /* If lookup found a member function, the Koenig lookup is
13711 not appropriate, even if an unqualified-name was used
13712 to denote the function. */
13715 /* Only do this when substitution turns a dependent call
13716 into a non-dependent call. */
13720 tf_none);
13724 {
13726 {
13727 /* For backwards compatibility and good diagnostics, try
13728 the unqualified lookup again if we aren't in SFINAE
13729 context. */
13730 tree unq = (tsubst_copy_and_build
13732 integral_constant_expression_p));
13737 {
13746 "%qD was not declared in this scope, "
13747 "and no declarations were found by "
13748 "argument-dependent lookup at the point "
13753 {
13755 "declarations in dependent base %qT are "
13761 else
13765 }
13766 else
13770 }
13771 }
13773 {
13778 }
13779 }
13781 /* Remember that there was a reference to this entity. */
13787 complain);
13789 {
13804 complain);
13805 else
13806 ret = (build_new_method_call
13811 complain));
13812 }
13813 else
13816 koenig_p,
13817 complain);
13822 }
13825 {
13830 {
13832 {
13837 }
13838 else
13839 {
13844 }
13845 }
13846 else
13847 {
13850 }
13854 }
13863 {
13871 {
13872 /* We have pack expansions, so expand those and
13873 create a new list out of it. */
13876 tree chain;
13879 /* Expand the argument expressions. */
13887 /* Build the rest of the list. */
13892 /* Determine the number of arguments. */
13894 {
13897 }
13900 else
13901 {
13902 /* Since we only performed a partial substitution into
13903 the argument pack, we only RETURN (a single list
13904 node. */
13911 }
13913 /* Convert the argument vectors into a TREE_LIST */
13916 {
13917 /* Grab the Ith values. */
13918 i--;
13921 value
13925 /* Build the list (backwards). */
13927 }
13930 }
13946 }
13949 {
13950 tree object;
13951 tree object_type;
13952 tree member;
13956 /* Remember that there was a reference to this entity. */
13966 else
13974 {
13976 {
13981 {
13984 }
13986 {
13990 }
13991 }
13992 }
13995 {
13996 /* Lookup the template functions now that we know what the
13997 scope is. */
14005 {
14008 args);
14009 member = (adjust_result_of_qualified_name_lookup
14011 object_type));
14012 }
14013 else
14014 {
14016 input_location);
14018 }
14019 }
14023 {
14025 {
14029 else
14032 }
14034 }
14040 complain));
14041 }
14048 {
14056 tree r;
14061 /* digest_init will do the wrong thing if we let it. */
14065 /* We do not want to process the index of aggregate
14066 initializers as they are identifier nodes which will be
14067 looked up by digest_init. */
14073 {
14078 {
14079 /* Substitute into the pack expansion. */
14081 in_decl);
14085 ;
14087 /* Just move the argument into place. */
14089 else
14090 {
14091 /* Update the length of the final CONSTRUCTOR
14092 arguments vector, and note that we will need to
14093 copy.*/
14096 }
14097 }
14098 else
14100 }
14103 {
14108 {
14110 {
14115 }
14116 else
14118 }
14119 }
14129 }
14132 {
14135 {
14138 }
14139 else
14140 {
14143 }
14144 }
14149 /* Fall through */
14152 {
14156 /* If the original type was a reference, we'll be wrapped in
14157 the appropriate INDIRECT_REF. */
14160 }
14171 {
14180 }
14183 {
14189 integral_constant_expression_p);
14193 /* If the resulting list of expression statement is empty,
14194 fold it further into void_zero_node. */
14199 }
14202 {
14216 /* For a function scope, we want to use tsubst so that we don't
14217 complain about referring to an auto function before its return
14218 type has been deduced. Otherwise, we want to use tsubst_copy so
14219 that we look up the existing field/parameter/variable rather
14220 than build a new one. */
14225 else
14234 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
14236 /* Now that we know visibility, instantiate the type so we have a
14237 declaration of the op() for later calls to lambda_function. */
14240 /* The capture list refers to closure members, so this needs to
14241 wait until after we finish instantiating the type. */
14246 }
14249 /* We can get here for a constant initializer of non-dependent type.
14250 FIXME stop folding in cp_parser_initializer_clause. */
14252 {
14256 }
14260 integral_constant_expression_p));
14263 /* Handle Objective-C++ constructs, if appropriate. */
14264 {
14265 tree subst
14270 }
14272 }
14274 #undef RECUR
14275 #undef RETURN
14276 out:
14279 }
14281 /* Verify that the instantiated ARGS are valid. For type arguments,
14282 make sure that the type's linkage is ok. For non-type arguments,
14283 make sure they are constants if they are integral or enumerations.
14284 Emit an error under control of COMPLAIN, and return TRUE on error. */
14286 static bool
14288 {
14290 {
14300 }
14302 {
14303 /* [basic.link]: A name with no linkage (notably, the name
14304 of a class or enumeration declared in a local scope)
14305 shall not be used to declare an entity with linkage.
14306 This implies that names with no linkage cannot be used as
14307 template arguments
14309 DR 757 relaxes this restriction for C++0x. */
14314 {
14315 /* DR 488 makes use of a type with no linkage cause
14316 type deduction to fail. */
14318 {
14321 else
14324 }
14326 }
14327 /* In order to avoid all sorts of complications, we do not
14328 allow variably-modified types as template arguments. */
14330 {
14334 }
14335 }
14336 /* A non-type argument of integral or enumerated type must be a
14337 constant. */
14341 {
14345 }
14347 }
14349 static bool
14351 {
14356 {
14359 }
14363 }
14365 /* We're out of SFINAE context now, so generate diagnostics for the access
14366 errors we saw earlier when instantiating D from TMPL and ARGS. */
14368 static void
14370 {
14382 }
14384 /* Instantiate the indicated variable, function, or alias template TMPL with
14385 the template arguments in TARG_PTR. */
14387 static tree
14389 {
14391 tree fndecl;
14392 tree gen_tmpl;
14393 tree spec;
14401 /* If this function is a clone, handle it specially. */
14403 {
14404 tree spec;
14405 tree clone;
14407 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
14408 DECL_CLONED_FUNCTION. */
14414 /* Look for the clone. */
14418 /* We should always have found the clone by now. */
14421 }
14423 /* Check to see if we already have this specialization. */
14426 /* The TMPL is a partial instantiation. To get a full set of
14427 arguments we must add the arguments used to perform the
14428 partial instantiation. */
14430 targ_ptr);
14432 /* It would be nice to avoid hashing here and then again in tsubst_decl,
14433 but it doesn't seem to be on the hot path. */
14442 {
14444 {
14448 }
14450 }
14453 complain))
14456 /* We are building a FUNCTION_DECL, during which the access of its
14457 parameters and return types have to be checked. However this
14458 FUNCTION_DECL which is the desired context for access checking
14459 is not built yet. We solve this chicken-and-egg problem by
14460 deferring all checks until we have the FUNCTION_DECL. */
14463 /* Instantiation of the function happens in the context of the function
14464 template, not the context of the overload resolution we're doing. */
14466 /* If there are dependent arguments, e.g. because we're doing partial
14467 ordering, make sure processing_template_decl stays set. */
14471 {
14475 }
14476 /* Substitute template parameters to obtain the specialization. */
14484 {
14487 }
14489 /* The DECL_TI_TEMPLATE should always be the immediate parent
14490 template, not the most general template. */
14493 /* Now we know the specialization, compute access previously
14494 deferred. */
14501 /* If we've just instantiated the main entry point for a function,
14502 instantiate all the alternate entry points as well. We do this
14503 by cloning the instantiation of the main entry point, not by
14504 instantiating the template clones. */
14509 {
14511 {
14512 /* Remember to reinstantiate when we're out of SFINAE so the user
14513 can see the errors. */
14515 }
14517 }
14519 }
14521 /* Wrapper for instantiate_template_1. */
14523 tree
14525 {
14526 tree ret;
14531 }
14533 /* Instantiate the alias template TMPL with ARGS. Also push a template
14534 instantiation level, which instantiate_template doesn't do because
14535 functions and variables have sufficient context established by the
14536 callers. */
14538 static tree
14540 {
14547 {
14550 }
14553 /* We can't free this if a pending_template entry or last_error_tinst_level
14554 is pointing at it. */
14560 }
14562 /* PARM is a template parameter pack for FN. Returns true iff
14563 PARM is used in a deducible way in the argument list of FN. */
14565 static bool
14567 {
14570 {
14572 tree packs;
14578 {
14579 /* The template parameter pack is used in a function parameter
14580 pack. If this is the end of the parameter list, the
14581 template parameter pack is deducible. */
14584 else
14585 /* Otherwise, not. Well, it could be deduced from
14586 a non-pack parameter, but doing so would end up with
14587 a deduction mismatch, so don't bother. */
14589 }
14590 }
14591 /* The template parameter pack isn't used in any function parameter
14592 packs, but it might be used deeper, e.g. tuple<Args...>. */
14594 }
14596 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
14597 NARGS elements of the arguments that are being used when calling
14598 it. TARGS is a vector into which the deduced template arguments
14599 are placed.
14601 Return zero for success, 2 for an incomplete match that doesn't resolve
14602 all the types, and 1 for complete failure. An error message will be
14603 printed only for an incomplete match.
14605 If FN is a conversion operator, or we are trying to produce a specific
14606 specialization, RETURN_TYPE is the return type desired.
14608 The EXPLICIT_TARGS are explicit template arguments provided via a
14609 template-id.
14611 The parameter STRICT is one of:
14613 DEDUCE_CALL:
14614 We are deducing arguments for a function call, as in
14615 [temp.deduct.call].
14617 DEDUCE_CONV:
14618 We are deducing arguments for a conversion function, as in
14619 [temp.deduct.conv].
14621 DEDUCE_EXACT:
14622 We are deducing arguments when doing an explicit instantiation
14623 as in [temp.explicit], when determining an explicit specialization
14624 as in [temp.expl.spec], or when taking the address of a function
14625 template, as in [temp.deduct.funcaddr]. */
14627 tree
14629 tree explicit_targs,
14630 tree targs,
14633 tree return_type,
14634 unification_kind_t strict,
14637 {
14638 tree parms;
14639 tree fntype;
14647 tree tinst;
14650 /* Adjust any explicit template arguments before entering the
14651 substitution context. */
14653 {
14654 explicit_targs
14656 complain,
14661 }
14663 /* In C++0x, it's possible to have a function template whose type depends
14664 on itself recursively. This is most obvious with decltype, but can also
14665 occur with enumeration scope (c++/48969). So we need to catch infinite
14666 recursion and reject the substitution at deduction time; this function
14667 will return error_mark_node for any repeated substitution.
14669 This also catches excessive recursion such as when f<N> depends on
14670 f<N-1> across all integers, and returns error_mark_node for all the
14671 substitutions back up to the initial one.
14673 This is, of course, not reentrant. */
14678 {
14682 }
14690 {
14691 /* [temp.deduct]
14693 The specified template arguments must match the template
14694 parameters in kind (i.e., type, nontype, template), and there
14695 must not be more arguments than there are parameters;
14696 otherwise type deduction fails.
14698 Nontype arguments must match the types of the corresponding
14699 nontype template parameters, or must be convertible to the
14700 types of the corresponding nontype parameters as specified in
14701 _temp.arg.nontype_, otherwise type deduction fails.
14703 All references in the function type of the function template
14704 to the corresponding template parameters are replaced by the
14705 specified template argument values. If a substitution in a
14706 template parameter or in the function type of the function
14707 template results in an invalid type, type deduction fails. */
14712 /* Substitute the explicit args into the function type. This is
14713 necessary so that, for instance, explicitly declared function
14714 arguments can match null pointed constants. If we were given
14715 an incomplete set of explicit args, we must not do semantic
14716 processing during substitution as we could create partial
14717 instantiations. */
14719 {
14724 /* Dig out the actual parm. */
14727 {
14730 }
14732 {
14735 }
14738 /* No explicit argument for this template parameter. */
14742 {
14743 /* Mark the argument pack as "incomplete". We could
14744 still deduce more arguments during unification.
14745 We remove this mark in type_unification_real. */
14747 {
14751 }
14753 /* We have some incomplete argument packs. */
14755 }
14756 }
14768 /* Place the explicitly specified arguments in TARGS. */
14771 }
14773 /* Never do unification on the 'this' parameter. */
14777 {
14786 }
14788 /* We allow incomplete unification without an error message here
14789 because the standard doesn't seem to explicitly prohibit it. Our
14790 callers must be ready to deal with unification failures in any
14791 event. */
14801 /* Now that we have bindings for all of the template arguments,
14802 ensure that the arguments deduced for the template template
14803 parameters have compatible template parameter lists. We cannot
14804 check this property before we have deduced all template
14805 arguments, because the template parameter types of a template
14806 template parameter might depend on prior template parameters
14807 deduced after the template template parameter. The following
14808 ill-formed example illustrates this issue:
14810 template<typename T, template<T> class C> void f(C<5>, T);
14812 template<int N> struct X {};
14814 void g() {
14815 f(X<5>(), 5l); // error: template argument deduction fails
14816 }
14818 The template parameter list of 'C' depends on the template type
14819 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
14820 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
14821 time that we deduce 'C'. */
14824 {
14827 }
14829 /* All is well so far. Now, check:
14831 [temp.deduct]
14833 When all template arguments have been deduced, all uses of
14834 template parameters in nondeduced contexts are replaced with
14835 the corresponding deduced argument values. If the
14836 substitution results in an invalid type, as described above,
14837 type deduction fails. */
14842 /* Now perform any access checks encountered during deduction, such as
14843 for default template arguments. */
14850 /* If we're looking for an exact match, check that what we got
14851 is indeed an exact match. It might not be if some template
14852 parameters are used in non-deduced contexts. */
14854 {
14858 tree sarg
14864 {
14868 }
14869 }
14873 fail:
14877 {
14879 /* Reset once we're all the way out. */
14881 }
14884 /* We can't free this if a pending_template entry or last_error_tinst_level
14885 is pointing at it. */
14891 }
14893 /* Adjust types before performing type deduction, as described in
14894 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
14895 sections are symmetric. PARM is the type of a function parameter
14896 or the return type of the conversion function. ARG is the type of
14897 the argument passed to the call, or the type of the value
14898 initialized with the result of the conversion function.
14899 ARG_EXPR is the original argument expression, which may be null. */
14901 static int
14905 tree arg_expr)
14906 {
14910 {
14915 {
14916 /* Swap PARM and ARG throughout the remainder of this
14917 function; the handling is precisely symmetric since PARM
14918 will initialize ARG rather than vice versa. */
14923 }
14926 /* Core issue #873: Do the DR606 thing (see below) for these cases,
14927 too, but here handle it by stripping the reference from PARM
14928 rather than by adding it to ARG. */
14936 /* Nothing else to do in this case. */
14941 }
14944 {
14945 /* [temp.deduct.call]
14947 If P is not a reference type:
14949 --If A is an array type, the pointer type produced by the
14950 array-to-pointer standard conversion (_conv.array_) is
14951 used in place of A for type deduction; otherwise,
14953 --If A is a function type, the pointer type produced by
14954 the function-to-pointer standard conversion
14955 (_conv.func_) is used in place of A for type deduction;
14956 otherwise,
14958 --If A is a cv-qualified type, the top level
14959 cv-qualifiers of A's type are ignored for type
14960 deduction. */
14965 else
14967 }
14969 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
14970 of the form T&&, where T is a template parameter, and the argument
14971 is an lvalue, T is deduced as A& */
14977 /* try_one_overload doesn't provide an arg_expr, but
14978 functions are always lvalues. */
14982 /* [temp.deduct.call]
14984 If P is a cv-qualified type, the top level cv-qualifiers
14985 of P's type are ignored for type deduction. If P is a
14986 reference type, the type referred to by P is used for
14987 type deduction. */
14990 {
14993 }
14995 /* DR 322. For conversion deduction, remove a reference type on parm
14996 too (which has been swapped into ARG). */
15001 }
15003 /* Subroutine of unify_one_argument. PARM is a function parameter of a
15004 template which does contain any deducible template parameters; check if
15005 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
15006 unify_one_argument. */
15008 static int
15011 {
15012 tree type;
15016 else
15023 {
15027 }
15029 {
15034 }
15038 else
15040 }
15042 /* Subroutine of type_unification_real and unify_pack_expansion to
15043 handle unification of a single P/A pair. Parameters are as
15044 for those functions. */
15046 static int
15050 {
15057 /* We can't deduce anything from this, but we might get all the
15058 template args from other function args. */
15061 /* FIXME uses_deducible_template_parms */
15064 explain_p);
15067 {
15069 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
15070 | UNIFY_ALLOW_MORE_CV_QUAL
15084 }
15086 /* We only do these transformations if this is the top-level
15087 parameter_type_list in a call or declaration matching; in other
15088 situations (nested function declarators, template argument lists) we
15089 won't be comparing a type to an expression, and we don't do any type
15090 adjustments. */
15092 {
15094 {
15097 {
15098 /* [temp.deduct.type] A template-argument can be
15099 deduced from a pointer to function or pointer
15100 to member function argument if the set of
15101 overloaded functions does not contain function
15102 templates and at most one of a set of
15103 overloaded functions provides a unique
15104 match. */
15111 }
15117 }
15119 arg_strict |=
15121 }
15122 else
15126 /* For deduction from an init-list we need the actual list. */
15130 }
15132 /* Most parms like fn_type_unification.
15134 If SUBR is 1, we're being called recursively (to unify the
15135 arguments of a function or method parameter of a function
15136 template). */
15138 static int
15140 tree targs,
15141 tree xparms,
15145 unification_kind_t strict,
15148 {
15153 tree parms;
15162 /* Reset the number of non-defaulted template arguments contained
15163 in TARGS. */
15166 again:
15174 {
15179 /* For a function parameter pack that occurs at the end of the
15180 parameter-declaration-list, the type A of each remaining
15181 argument of the call is compared with the type P of the
15182 declarator-id of the function parameter pack. */
15188 /* For a function parameter pack that does not occur at the
15189 end of the parameter-declaration-list, the type of the
15190 parameter pack is a non-deduced context. */
15199 }
15204 {
15205 /* Unify the remaining arguments with the pack expansion type. */
15206 tree argvec;
15209 /* Allocate a TREE_VEC and copy in all of the arguments */
15214 /* Copy the parameter into parmvec. */
15220 /* Advance to the end of the list of parameters. */
15222 }
15224 /* Fail if we've reached the end of the parm list, and more args
15225 are present, and the parm list isn't variadic. */
15228 /* Fail if parms are left and they don't have default values. */
15231 {
15235 {
15236 count++;
15238 }
15240 }
15243 {
15244 tsubst_flags_t complain = (explain_p
15245 ? tf_warning_or_error
15248 /* Check to see if we need another pass before we start clearing
15249 ARGUMENT_PACK_INCOMPLETE_P. */
15251 {
15259 /* If this is an undeduced nontype parameter that depends on
15260 a type parameter, try another pass; its type may have been
15261 deduced from a later argument than the one from which
15262 this parameter can be deduced. */
15267 }
15270 {
15274 /* Clear the "incomplete" flags on all argument packs now so that
15275 substituting them into later default arguments works. */
15277 {
15280 }
15286 /* Core issue #226 (C++0x) [temp.deduct]:
15288 If a template argument has not been deduced, its
15289 default template argument, if any, is used.
15291 When we are in C++98 mode, TREE_PURPOSE will either
15292 be NULL_TREE or ERROR_MARK_NODE, so we do not need
15293 to explicitly check cxx_dialect here. */
15295 {
15307 else
15308 {
15310 /* The position of the first default template argument,
15311 is also the number of non-defaulted arguments in TARGS.
15312 Record that. */
15316 }
15317 }
15319 /* If the type parameter is a parameter pack, then it will
15320 be deduced to an empty parameter pack. */
15322 {
15323 tree arg;
15326 {
15330 }
15331 else
15338 }
15341 }
15342 }
15343 #ifdef ENABLE_CHECKING
15346 #endif
15349 }
15351 /* Subroutine of type_unification_real. Args are like the variables
15352 at the call site. ARG is an overloaded function (or template-id);
15353 we try deducing template args from each of the overloads, and if
15354 only one succeeds, we go with that. Modifies TARGS and returns
15355 true on success. */
15357 static bool
15359 tree targs,
15360 tree parm,
15361 tree arg,
15362 unification_kind_t strict,
15365 {
15372 {
15375 }
15376 else
15380 /* Handle `&x' where `x' is some static or non-static member
15381 function name. */
15387 /* Strip baselink information. */
15392 {
15393 /* If we got some explicit template args, we need to plug them into
15394 the affected templates before we try to unify, in case the
15395 explicit args will completely resolve the templates in question. */
15402 {
15415 {
15420 {
15423 }
15424 }
15427 }
15428 /* If no templates (or more than one) are fully resolved by the
15429 explicit arguments, this template-id is a non-deduced context; it
15430 could still be OK if we deduce all template arguments for the
15431 enclosing call through other arguments. */
15434 }
15437 /* If ARG is, for example, "(0, &f)" then its type will be unknown
15438 -- but the deduction does not succeed because the expression is
15439 not just the function on its own. */
15441 else
15447 {
15450 }
15452 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15453 to function or pointer to member function argument if the set of
15454 overloaded functions does not contain function templates and at most
15455 one of a set of overloaded functions provides a unique match.
15457 So if we found multiple possibilities, we return success but don't
15458 deduce anything. */
15461 {
15466 }
15471 }
15473 /* Core DR 115: In contexts where deduction is done and fails, or in
15474 contexts where deduction is not done, if a template argument list is
15475 specified and it, along with any default template arguments, identifies
15476 a single function template specialization, then the template-id is an
15477 lvalue for the function template specialization. */
15479 tree
15481 {
15494 {
15497 }
15499 {
15502 }
15504 {
15507 }
15510 {
15514 /* If we got some explicit template args, we need to plug them into
15515 the affected templates before we try to unify, in case the
15516 explicit args will completely resolve the templates in question. */
15524 {
15537 {
15540 {
15543 }
15545 {
15548 }
15549 }
15550 }
15552 {
15560 {
15561 tree base
15564 }
15568 }
15570 /* There were no good options and at least one bad one, so let the
15571 user know what the problem is. */
15573 }
15575 }
15577 /* Subroutine of resolve_overloaded_unification; does deduction for a single
15578 overload. Fills TARGS with any deduced arguments, or error_mark_node if
15579 different overloads deduce different arguments for a given parm.
15580 ADDR_P is true if the expression for which deduction is being
15581 performed was of the form "& fn" rather than simply "fn".
15583 Returns 1 on success. */
15585 static int
15587 tree orig_targs,
15588 tree targs,
15589 tree parm,
15590 tree arg,
15591 unification_kind_t strict,
15595 {
15597 tree tempargs;
15603 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15604 to function or pointer to member function argument if the set of
15605 overloaded functions does not contain function templates and at most
15606 one of a set of overloaded functions provides a unique match.
15608 So if this is a template, just return success. */
15620 /* We don't copy orig_targs for this because if we have already deduced
15621 some template args from previous args, unify would complain when we
15622 try to deduce a template parameter for the same argument, even though
15623 there isn't really a conflict. */
15630 /* First make sure we didn't deduce anything that conflicts with
15631 explicitly specified args. */
15633 {
15640 /* Since we're unifying against ourselves, we will fill in
15641 template args used in the function parm list with our own
15642 template parms. Discard them. */
15646 }
15649 {
15654 }
15657 }
15659 /* PARM is a template class (perhaps with unbound template
15660 parameters). ARG is a fully instantiated type. If ARG can be
15661 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
15662 TARGS are as for unify. */
15664 static tree
15667 {
15668 tree copy_of_targs;
15675 /* We need to make a new template argument vector for the call to
15676 unify. If we used TARGS, we'd clutter it up with the result of
15677 the attempted unification, even if this class didn't work out.
15678 We also don't want to commit ourselves to all the unifications
15679 we've already done, since unification is supposed to be done on
15680 an argument-by-argument basis. In other words, consider the
15681 following pathological case:
15683 template <int I, int J, int K>
15684 struct S {};
15686 template <int I, int J>
15687 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
15689 template <int I, int J, int K>
15690 void f(S<I, J, K>, S<I, I, I>);
15692 void g() {
15693 S<0, 0, 0> s0;
15694 S<0, 1, 2> s2;
15696 f(s0, s2);
15697 }
15699 Now, by the time we consider the unification involving `s2', we
15700 already know that we must have `f<0, 0, 0>'. But, even though
15701 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
15702 because there are two ways to unify base classes of S<0, 1, 2>
15703 with S<I, I, I>. If we kept the already deduced knowledge, we
15704 would reject the possibility I=1. */
15707 /* If unification failed, we're done. */
15713 }
15715 /* Given a template type PARM and a class type ARG, find the unique
15716 base type in ARG that is an instance of PARM. We do not examine
15717 ARG itself; only its base-classes. If there is not exactly one
15718 appropriate base class, return NULL_TREE. PARM may be the type of
15719 a partial specialization, as well as a plain template type. Used
15720 by unify. */
15722 static enum template_base_result
15725 {
15727 tree binfo;
15733 {
15734 /* The type could not be completed. */
15737 }
15739 /* Walk in inheritance graph order. The search order is not
15740 important, and this avoids multiple walks of virtual bases. */
15742 {
15747 {
15748 /* If there is more than one satisfactory baseclass, then:
15750 [temp.deduct.call]
15752 If they yield more than one possible deduced A, the type
15753 deduction fails.
15755 applies. */
15757 {
15760 }
15763 }
15764 }
15768 }
15770 /* Returns the level of DECL, which declares a template parameter. */
15772 static int
15774 {
15776 {
15786 }
15788 }
15790 /* Decide whether ARG can be unified with PARM, considering only the
15791 cv-qualifiers of each type, given STRICT as documented for unify.
15792 Returns nonzero iff the unification is OK on that basis. */
15794 static int
15796 {
15802 {
15803 /* Although a CVR qualifier is ignored when being applied to a
15804 substituted template parameter ([8.3.2]/1 for example), that
15805 does not allow us to unify "const T" with "int&" because both
15806 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
15807 It is ok when we're allowing additional CV qualifiers
15808 at the outer level [14.8.2.1]/3,1st bullet. */
15818 }
15829 }
15831 /* Determines the LEVEL and INDEX for the template parameter PARM. */
15832 void
15834 {
15838 {
15841 }
15842 else
15843 {
15846 }
15847 }
15849 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
15850 do { \
15851 if (unify (TP, TA, P, A, S, EP)) \
15852 return 1; \
15853 } while (0);
15855 /* Unifies the remaining arguments in PACKED_ARGS with the pack
15856 expansion at the end of PACKED_PARMS. Returns 0 if the type
15857 deduction succeeds, 1 otherwise. STRICT is the same as in
15858 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
15859 call argument list. We'll need to adjust the arguments to make them
15860 types. SUBR tells us if this is from a recursive call to
15861 type_unification_real, or for comparing two template argument
15862 lists. */
15864 static int
15868 {
15869 tree parm
15876 /* Determine the parameter packs we will be deducing from the
15877 pattern, and record their current deductions. */
15880 {
15884 /* Determine the index and level of this parameter pack. */
15887 /* Keep track of the parameter packs and their corresponding
15888 argument packs. */
15891 }
15893 /* Loop through all of the arguments that have not yet been
15894 unified and unify each with the pattern. */
15896 {
15897 tree parm;
15901 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
15902 or the element of its argument pack at the current index if
15903 this argument was explicitly specified. */
15905 {
15914 {
15917 }
15919 }
15921 /* If we had explicit template arguments, substitute them into the
15922 pattern before deduction. */
15924 {
15925 /* Some arguments might still be unspecified or dependent. */
15933 NULL_TREE);
15938 }
15939 else
15942 /* Unify the pattern with the current argument. */
15947 /* For each parameter pack, collect the deduced value. */
15949 {
15955 }
15956 }
15958 /* Verify that the results of unification with the parameter packs
15959 produce results consistent with what we've seen before, and make
15960 the deduced argument packs available. */
15962 {
15969 /* By default keep the original deduced argument pack.
15970 If necessary, more specific code is going to update the
15971 resulting deduced argument later down in this function. */
15975 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
15976 actually deduce anything. */
15984 {
15985 /* If we had fewer function args than explicit template args,
15986 just use the explicits. */
15991 }
15994 {
15995 tree result;
15996 /* Build the deduced *_ARGUMENT_PACK. */
15998 {
16003 }
16004 else
16009 /* Note the deduced argument packs for this parameter
16010 pack. */
16012 }
16016 {
16017 /* We only had the explicitly-provided arguments before, but
16018 now we have a complete set of arguments. */
16024 }
16025 else
16026 {
16032 /* Inconsistent unification of this parameter pack. */
16034 bad_old_arg,
16035 bad_new_arg);
16036 }
16037 }
16040 }
16042 /* Deduce the value of template parameters. TPARMS is the (innermost)
16043 set of template parameters to a template. TARGS is the bindings
16044 for those template parameters, as determined thus far; TARGS may
16045 include template arguments for outer levels of template parameters
16046 as well. PARM is a parameter to a template function, or a
16047 subcomponent of that parameter; ARG is the corresponding argument.
16048 This function attempts to match PARM with ARG in a manner
16049 consistent with the existing assignments in TARGS. If more values
16050 are deduced, then TARGS is updated.
16052 Returns 0 if the type deduction succeeds, 1 otherwise. The
16053 parameter STRICT is a bitwise or of the following flags:
16055 UNIFY_ALLOW_NONE:
16056 Require an exact match between PARM and ARG.
16057 UNIFY_ALLOW_MORE_CV_QUAL:
16058 Allow the deduced ARG to be more cv-qualified (by qualification
16059 conversion) than ARG.
16060 UNIFY_ALLOW_LESS_CV_QUAL:
16061 Allow the deduced ARG to be less cv-qualified than ARG.
16062 UNIFY_ALLOW_DERIVED:
16063 Allow the deduced ARG to be a template base class of ARG,
16064 or a pointer to a template base class of the type pointed to by
16065 ARG.
16066 UNIFY_ALLOW_INTEGER:
16067 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
16068 case for more information.
16069 UNIFY_ALLOW_OUTER_LEVEL:
16070 This is the outermost level of a deduction. Used to determine validity
16071 of qualification conversions. A valid qualification conversion must
16072 have const qualified pointers leading up to the inner type which
16073 requires additional CV quals, except at the outer level, where const
16074 is not required [conv.qual]. It would be normal to set this flag in
16075 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
16076 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
16077 This is the outermost level of a deduction, and PARM can be more CV
16078 qualified at this point.
16079 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
16080 This is the outermost level of a deduction, and PARM can be less CV
16081 qualified at this point. */
16083 static int
16086 {
16088 tree targ;
16089 tree tparm;
16092 /* I don't think this will do the right thing with respect to types.
16093 But the only case I've seen it in so far has been array bounds, where
16094 signedness is the only information lost, and I think that will be
16095 okay. */
16103 /* We can't deduce anything from this, but we might get all the
16104 template args from other function args. */
16107 /* If PARM uses template parameters, then we can't bail out here,
16108 even if ARG == PARM, since we won't record unifications for the
16109 template parameters. We might need them if we're trying to
16110 figure out which of two things is more specialized. */
16114 /* Handle init lists early, so the rest of the function can assume
16115 we're dealing with a type. */
16117 {
16122 /* Replace T with std::initializer_list<T> for deduction. */
16128 /* We can only deduce from an initializer list argument if the
16129 parameter is std::initializer_list; otherwise this is a
16130 non-deduced context. */
16136 {
16143 {
16145 /* It should only be possible to get here for a call. */
16147 elt_strict |= maybe_adjust_types_for_deduction
16150 }
16153 explain_p);
16154 }
16156 /* If the std::initializer_list<T> deduction worked, replace the
16157 deduced A with std::initializer_list<A>. */
16159 {
16164 }
16166 }
16168 /* Immediately reject some pairs that won't unify because of
16169 cv-qualification mismatches. */
16172 /* It is the elements of the array which hold the cv quals of an array
16173 type, and the elements might be template type parms. We'll check
16174 when we recurse. */
16176 /* We check the cv-qualifiers when unifying with template type
16177 parameters below. We want to allow ARG `const T' to unify with
16178 PARM `T' for example, when computing which of two templates
16179 is more specialized, for example. */
16193 {
16197 /* In a type which contains a nested-name-specifier, template
16198 argument values cannot be deduced for template parameters used
16199 within the nested-name-specifier. */
16211 /* The PARM is not one we're trying to unify. Just check
16212 to see if it matches ARG. */
16213 {
16218 else
16220 }
16227 /* Check for mixed types and values. */
16235 {
16236 /* ARG must be constructed from a template class or a template
16237 template parameter. */
16242 {
16246 tree parm_parms
16247 = DECL_INNERMOST_TEMPLATE_PARMS
16252 /* The resolution to DR150 makes clear that default
16253 arguments for an N-argument may not be used to bind T
16254 to a template template parameter with fewer than N
16255 parameters. It is not safe to permit the binding of
16256 default arguments as an extension, as that may change
16257 the meaning of a conforming program. Consider:
16259 struct Dense { static const unsigned int dim = 1; };
16261 template <template <typename> class View,
16262 typename Block>
16263 void operator+(float, View<Block> const&);
16265 template <typename Block,
16266 unsigned int Dim = Block::dim>
16267 struct Lvalue_proxy { operator float() const; };
16269 void
16270 test_1d (void) {
16271 Lvalue_proxy<Dense> p;
16272 float b;
16273 b + p;
16274 }
16276 Here, if Lvalue_proxy is permitted to bind to View, then
16277 the global operator+ will be used; if they are not, the
16278 Lvalue_proxy will be converted to float. */
16280 full_argvec,
16282 (explain_p
16283 ? tf_warning_or_error
16290 /* Deduce arguments T, i from TT<T> or TT<i>.
16291 We check each element of PARMVEC and ARGVEC individually
16292 rather than the whole TREE_VEC since they can have
16293 different number of elements. */
16300 /* Check if the parameters end in a pack, making them
16301 variadic. */
16311 {
16316 }
16321 DEDUCE_EXACT,
16324 }
16327 /* Fall through to deduce template name. */
16328 }
16332 {
16333 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
16335 /* Simple cases: Value already set, does match or doesn't. */
16340 }
16341 else
16342 {
16343 /* If PARM is `const T' and ARG is only `int', we don't have
16344 a match unless we are allowing additional qualification.
16345 If ARG is `const int' and PARM is just `T' that's OK;
16346 that binds `const int' to `T'. */
16351 /* Consider the case where ARG is `const volatile int' and
16352 PARM is `const T'. Then, T should be `volatile int'. */
16353 arg = cp_build_qualified_type_real
16358 /* Simple cases: Value already set, does match or doesn't. */
16364 /* Make sure that ARG is not a variable-sized array. (Note
16365 that were talking about variable-sized arrays (like
16366 `int[n]'), rather than arrays of unknown size (like
16367 `int[]').) We'll get very confused by such a type since
16368 the bound of the array is not constant, and therefore
16369 not mangleable. Besides, such types are not allowed in
16370 ISO C++, so we can do as we please here. We do allow
16371 them for 'auto' deduction, since that isn't ABI-exposed. */
16375 /* Strip typedefs as in convert_template_argument. */
16377 }
16379 /* If ARG is a parameter pack or an expansion, we cannot unify
16380 against it unless PARM is also a parameter pack. */
16385 /* If the argument deduction results is a METHOD_TYPE,
16386 then there is a problem.
16387 METHOD_TYPE doesn't map to any real C++ type the result of
16388 the deduction can not be of that type. */
16402 {
16403 /* The PARM is not one we're trying to unify. Just check
16404 to see if it matches ARG. */
16410 }
16416 {
16421 }
16423 /* [temp.deduct.type] If, in the declaration of a function template
16424 with a non-type template-parameter, the non-type
16425 template-parameter is used in an expression in the function
16426 parameter-list and, if the corresponding template-argument is
16427 deduced, the template-argument type shall match the type of the
16428 template-parameter exactly, except that a template-argument
16429 deduced from an array bound may be of any integral type.
16430 The non-type parameter might use already deduced type parameters. */
16433 /* Template-parameter dependent expression. Just accept it for now.
16434 It will later be processed in convert_template_argument. */
16435 ;
16441 /* Convert the ARG to the type of PARM; the deduced non-type
16442 template argument must exactly match the types of the
16443 corresponding parameter. */
16446 /* We haven't deduced the type of this parameter yet. Try again
16447 later. */
16449 else
16452 /* If ARG is a parameter pack or an expansion, we cannot unify
16453 against it unless PARM is also a parameter pack. */
16463 {
16464 /* A pointer-to-member constant can be unified only with
16465 another constant. */
16469 /* Just unify the class member. It would be useless (and possibly
16470 wrong, depending on the strict flags) to unify also
16471 PTRMEM_CST_CLASS, because we want to be sure that both parm and
16472 arg refer to the same variable, even if through different
16473 classes. For instance:
16475 struct A { int x; };
16476 struct B : A { };
16478 Unification of &A::x and &B::x must succeed. */
16481 }
16484 {
16488 /* [temp.deduct.call]
16490 A can be another pointer or pointer to member type that can
16491 be converted to the deduced A via a qualification
16492 conversion (_conv.qual_).
16494 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
16495 This will allow for additional cv-qualification of the
16496 pointed-to types if appropriate. */
16499 /* The derived-to-base conversion only persists through one
16500 level of pointers. */
16505 }
16520 {
16521 tree parm_max;
16522 tree arg_max;
16526 /* Our representation of array types uses "N - 1" as the
16527 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
16528 not an integer constant. We cannot unify arbitrarily
16529 complex expressions, so we eliminate the MINUS_EXPRs
16530 here. */
16534 {
16537 }
16541 {
16542 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
16543 trying to unify the type of a variable with the type
16544 of a template parameter. For example:
16546 template <unsigned int N>
16547 void f (char (&) [N]);
16548 int g();
16549 void h(int i) {
16550 char a[g(i)];
16551 f(a);
16552 }
16554 Here, the type of the ARG will be "int [g(i)]", and
16555 may be a SAVE_EXPR, etc. */
16559 }
16561 /* If only one of the bounds used a MINUS_EXPR, compensate
16562 by adding one to the other bound. */
16565 integer_type_node,
16566 parm_max,
16567 integer_one_node);
16570 integer_type_node,
16571 arg_max,
16572 integer_one_node);
16576 }
16591 /* We have already checked cv-qualification at the top of the
16592 function. */
16596 /* As far as unification is concerned, this wins. Later checks
16597 will invalidate it if necessary. */
16600 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
16601 /* Type INTEGER_CST can come from ordinary constant template args. */
16613 {
16623 /* Check for pack expansions in the parameters. */
16625 {
16627 {
16629 /* We can unify against something with a trailing
16630 parameter pack. */
16632 else
16633 /* [temp.deduct.type]/9: If the template argument list of
16634 P contains a pack expansion that is not the last
16635 template argument, the entire template argument list
16636 is a non-deduced context. */
16638 }
16639 }
16641 /* If we don't have enough arguments to satisfy the parameters
16642 (not counting the pack expression at the end), or we have
16643 too many arguments for a parameter list that doesn't end in
16644 a pack expression, we can't unify. */
16650 /* Unify all of the parameters that precede the (optional)
16651 pack expression. */
16653 {
16658 }
16661 DEDUCE_EXACT,
16664 }
16672 {
16680 }
16683 {
16687 {
16688 /* First, we try to unify the PARM and ARG directly. */
16693 {
16694 /* Fallback to the special case allowed in
16695 [temp.deduct.call]:
16697 If P is a class, and P has the form
16698 template-id, then A can be a derived class of
16699 the deduced A. Likewise, if P is a pointer to
16700 a class of the form template-id, A can be a
16701 pointer to a derived class pointed to by the
16702 deduced A. */
16709 }
16710 }
16714 /* Perhaps PARM is something like S<U> and ARG is S<int>.
16715 Then, we should unify `int' and `U'. */
16717 else
16718 /* There's no chance of unification succeeding. */
16723 }
16730 {
16733 tree a;
16739 /* CV qualifications for methods can never be deduced, they must
16740 match exactly. We need to check them explicitly here,
16741 because type_unification_real treats them as any other
16742 cv-qualified parameter. */
16744 && (!check_cv_quals_for_unify
16764 }
16767 /* Unify a pointer to member with a pointer to member function, which
16768 deduces the type of the member as a function type. */
16770 {
16771 tree method_type;
16772 tree fntype;
16774 /* Check top-level cv qualifiers */
16782 /* Determine the type of the function we are unifying against. */
16784 fntype =
16788 /* Extract the cv-qualifiers of the member function from the
16789 implicit object parameter and place them on the function
16790 type to be restored later. */
16793 }
16812 /* Matched cases are handled by the ARG == PARM test above. */
16816 /* A non-type template parameter that is a variable should be a
16817 an integral constant, in which case, it whould have been
16818 folded into its (constant) value. So we should not be getting
16819 a variable here. */
16830 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
16831 or UNDERLYING_TYPE nodes. */
16835 /* Unification fails if we hit an error node. */
16839 /* An unresolved overload is a nondeduced context. */
16844 /* We must be looking at an expression. This can happen with
16845 something like:
16847 template <int I>
16848 void foo(S<I>, S<I + 2>);
16850 This is a "nondeduced context":
16852 [deduct.type]
16854 The nondeduced contexts are:
16856 --A type that is a template-id in which one or more of
16857 the template-arguments is an expression that references
16858 a template-parameter.
16860 In these cases, we assume deduction succeeded, but don't
16861 actually infer any unifications. */
16866 else
16868 }
16869 }
16870 #undef RECUR_AND_CHECK_FAILURE
16871 \f
16872 /* Note that DECL can be defined in this translation unit, if
16873 required. */
16875 static void
16877 {
16878 tree clone;
16882 }
16884 /* Called if RESULT is explicitly instantiated, or is a member of an
16885 explicitly instantiated class. */
16887 void
16889 {
16892 /* If this entity has already been written out, it's too late to
16893 make any modifications. */
16898 /* The TREE_PUBLIC flag for function declarations will have been
16899 set correctly by tsubst. */
16902 /* This might have been set by an earlier implicit instantiation. */
16907 else
16908 {
16910 /* Always make artificials weak. */
16913 /* For WIN32 we also want to put explicit instantiations in
16914 linkonce sections. */
16917 }
16919 /* If EXTERN_P, then this function will not be emitted -- unless
16920 followed by an explicit instantiation, at which point its linkage
16921 will be adjusted. If !EXTERN_P, then this function will be
16922 emitted here. In neither circumstance do we want
16923 import_export_decl to adjust the linkage. */
16925 }
16927 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
16928 important template arguments. If any are missing, we check whether
16929 they're important by using error_mark_node for substituting into any
16930 args that were used for partial ordering (the ones between ARGS and END)
16931 and seeing if it bubbles up. */
16933 static bool
16935 {
16940 {
16943 }
16945 {
16949 }
16951 }
16953 /* Given two function templates PAT1 and PAT2, return:
16955 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
16956 -1 if PAT2 is more specialized than PAT1.
16957 0 if neither is more specialized.
16959 LEN indicates the number of parameters we should consider
16960 (defaulted parameters should not be considered).
16962 The 1998 std underspecified function template partial ordering, and
16963 DR214 addresses the issue. We take pairs of arguments, one from
16964 each of the templates, and deduce them against each other. One of
16965 the templates will be more specialized if all the *other*
16966 template's arguments deduce against its arguments and at least one
16967 of its arguments *does* *not* deduce against the other template's
16968 corresponding argument. Deduction is done as for class templates.
16969 The arguments used in deduction have reference and top level cv
16970 qualifiers removed. Iff both arguments were originally reference
16971 types *and* deduction succeeds in both directions, the template
16972 with the more cv-qualified argument wins for that pairing (if
16973 neither is more cv-qualified, they both are equal). Unlike regular
16974 deduction, after all the arguments have been deduced in this way,
16975 we do *not* verify the deduced template argument values can be
16976 substituted into non-deduced contexts.
16978 The logic can be a bit confusing here, because we look at deduce1 and
16979 targs1 to see if pat2 is at least as specialized, and vice versa; if we
16980 can find template arguments for pat1 to make arg1 look like arg2, that
16981 means that arg2 is at least as specialized as arg1. */
16983 int
16985 {
16998 /* Remove the this parameter from non-static member functions. If
16999 one is a non-static member function and the other is not a static
17000 member function, remove the first parameter from that function
17001 also. This situation occurs for operator functions where we
17002 locate both a member function (with this pointer) and non-member
17003 operator (with explicit first operand). */
17005 {
17010 }
17012 {
17015 {
17016 len--;
17018 }
17019 }
17021 /* If only one is a conversion operator, they are unordered. */
17025 /* Consider the return type for a conversion function */
17027 {
17030 len++;
17031 }
17033 processing_template_decl++;
17039 /* Stop when an ellipsis is seen. */
17041 {
17050 {
17051 /* When both arguments are pack expansions, we need only
17052 unify the patterns themselves. */
17056 /* This is the last comparison we need to do. */
17058 }
17061 {
17064 }
17067 {
17070 }
17076 {
17082 /* Setup the parameter vector, which contains only ARG1. */
17085 /* Setup the argument vector, which contains the remaining
17086 arguments. */
17095 /* We cannot deduce in the other direction, because ARG1 is
17096 a pack expansion but ARG2 is not. */
17098 }
17100 {
17106 /* Setup the parameter vector, which contains only ARG1. */
17109 /* Setup the argument vector, which contains the remaining
17110 arguments. */
17119 /* We cannot deduce in the other direction, because ARG2 is
17120 a pack expansion but ARG1 is not.*/
17122 }
17124 else
17125 {
17126 /* The normal case, where neither argument is a pack
17127 expansion. */
17134 }
17136 /* If we couldn't deduce arguments for tparms1 to make arg1 match
17137 arg2, then arg2 is not as specialized as arg1. */
17143 /* "If, for a given type, deduction succeeds in both directions
17144 (i.e., the types are identical after the transformations above)
17145 and if the type from the argument template is more cv-qualified
17146 than the type from the parameter template (as described above)
17147 that type is considered to be more specialized than the other. If
17148 neither type is more cv-qualified than the other then neither type
17149 is more specialized than the other." */
17153 {
17158 }
17161 /* We've failed to deduce something in either direction.
17162 These must be unordered. */
17167 /* We have already processed all of the arguments in our
17168 handing of the pack expansion type. */
17173 }
17175 /* "In most cases, all template parameters must have values in order for
17176 deduction to succeed, but for partial ordering purposes a template
17177 parameter may remain without a value provided it is not used in the
17178 types being used for partial ordering."
17180 Thus, if we are missing any of the targs1 we need to substitute into
17181 origs1, then pat2 is not as specialized as pat1. This can happen when
17182 there is a nondeduced context. */
17188 processing_template_decl--;
17190 /* All things being equal, if the next argument is a pack expansion
17191 for one function but not for the other, prefer the
17192 non-variadic function. FIXME this is bogus; see c++/41958. */
17196 {
17199 }
17205 else
17207 }
17209 /* Determine which of two partial specializations of MAIN_TMPL is more
17210 specialized.
17212 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
17213 to the first partial specialization. The TREE_VALUE is the
17214 innermost set of template parameters for the partial
17215 specialization. PAT2 is similar, but for the second template.
17217 Return 1 if the first partial specialization is more specialized;
17218 -1 if the second is more specialized; 0 if neither is more
17219 specialized.
17221 See [temp.class.order] for information about determining which of
17222 two templates is more specialized. */
17224 static int
17226 {
17227 tree targs;
17235 /* Just like what happens for functions, if we are ordering between
17236 different class template specializations, we may encounter dependent
17237 types in the arguments, and we need our dependency check functions
17238 to behave correctly. */
17244 {
17247 }
17253 {
17256 }
17259 /* In the case of a tie where at least one of the class templates
17260 has a parameter pack at the end, the template with the most
17261 non-packed parameters wins. */
17263 && any_deductions
17266 {
17272 /* We don't count the pack expansion at the end. */
17282 }
17285 }
17287 /* Return the template arguments that will produce the function signature
17288 DECL from the function template FN, with the explicit template
17289 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
17290 also match. Return NULL_TREE if no satisfactory arguments could be
17291 found. */
17293 static tree
17295 {
17299 tree decl_arg_types;
17302 tree arg;
17306 /* Never do unification on the 'this' parameter. */
17326 }
17328 /* Return the innermost template arguments that, when applied to a partial
17329 specialization of MAIN_TMPL whose innermost template parameters are
17330 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
17331 ARGS.
17333 For example, suppose we have:
17335 template <class T, class U> struct S {};
17336 template <class T> struct S<T*, int> {};
17338 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
17339 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
17340 int}. The resulting vector will be {double}, indicating that `T'
17341 is bound to `double'. */
17343 static tree
17345 {
17347 tree deduced_args;
17348 tree innermost_deduced_args;
17352 {
17356 innermost_deduced_args);
17357 }
17358 else
17371 /* Verify that nondeduced template arguments agree with the type
17372 obtained from argument deduction.
17374 For example:
17376 struct A { typedef int X; };
17377 template <class T, class U> struct C {};
17378 template <class T> struct C<T, typename T::X> {};
17380 Then with the instantiation `C<A, int>', we can deduce that
17381 `T' is `A' but unify () does not check whether `typename T::X'
17382 is `int'. */
17388 /* We only need to check the innermost arguments; the other
17389 arguments will always agree. */
17394 /* Now that we have bindings for all of the template arguments,
17395 ensure that the arguments deduced for the template template
17396 parameters have compatible template parameter lists. See the use
17397 of template_template_parm_bindings_ok_p in fn_type_unification
17398 for more information. */
17403 }
17405 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
17406 Return the TREE_LIST node with the most specialized template, if
17407 any. If there is no most specialized template, the error_mark_node
17408 is returned.
17410 Note that this function does not look at, or modify, the
17411 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
17412 returned is one of the elements of INSTANTIATIONS, callers may
17413 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
17414 and retrieve it from the value returned. */
17416 tree
17418 {
17425 {
17431 fate--;
17436 fate++;
17441 {
17442 /* Equally specialized, move to next function. If there
17443 is no next function, nothing's most specialized. */
17448 }
17449 }
17452 /* Now verify that champ is better than everything earlier in the
17453 instantiation list. */
17461 {
17464 }
17466 processing_template_decl--;
17472 }
17474 /* If DECL is a specialization of some template, return the most
17475 general such template. Otherwise, returns NULL_TREE.
17477 For example, given:
17479 template <class T> struct S { template <class U> void f(U); };
17481 if TMPL is `template <class U> void S<int>::f(U)' this will return
17482 the full template. This function will not trace past partial
17483 specializations, however. For example, given in addition:
17485 template <class T> struct S<T*> { template <class U> void f(U); };
17487 if TMPL is `template <class U> void S<int*>::f(U)' this will return
17488 `template <class T> template <class U> S<T*>::f(U)'. */
17490 tree
17492 {
17493 /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is
17494 an immediate specialization. */
17496 {
17500 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a
17501 template friend. */
17506 }
17508 /* Look for more and more general templates. */
17510 {
17511 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
17512 (See cp-tree.h for details.) */
17520 /* Stop if we run into an explicitly specialized class template. */
17527 }
17530 }
17532 /* Return the most specialized of the class template partial
17533 specializations of TMPL which can produce TYPE, a specialization of
17534 TMPL. The value returned is actually a TREE_LIST; the TREE_TYPE is
17535 a _TYPE node corresponding to the partial specialization, while the
17536 TREE_PURPOSE is the set of template arguments that must be
17537 substituted into the TREE_TYPE in order to generate TYPE.
17539 If the choice of partial specialization is ambiguous, a diagnostic
17540 is issued, and the error_mark_node is returned. If there are no
17541 partial specializations of TMPL matching TYPE, then NULL_TREE is
17542 returned. */
17544 static tree
17546 {
17548 tree t;
17549 tree champ;
17552 tree args;
17558 /* For determining which partial specialization to use, only the
17559 innermost args are interesting. */
17561 {
17564 }
17567 {
17568 tree partial_spec_args;
17569 tree spec_args;
17577 {
17580 /* Discard the outer levels of args, and then substitute in the
17581 template args from the enclosing class. */
17583 partial_spec_args = tsubst_template_args
17586 /* PARMS already refers to just the innermost parms, but the
17587 template parms in partial_spec_args had their levels lowered
17588 by tsubst, so we need to do the same for the parm list. We
17589 can't just tsubst the TREE_VEC itself, as tsubst wants to
17590 treat a TREE_VEC as an argument vector. */
17596 }
17598 partial_spec_args =
17601 partial_spec_args),
17612 partial_spec_args,
17613 args);
17615 {
17620 }
17621 }
17631 {
17634 ;
17635 else
17636 {
17638 {
17641 {
17644 }
17645 }
17647 }
17648 }
17652 {
17655 {
17658 }
17659 }
17662 {
17670 {
17673 }
17676 }
17679 }
17681 /* Explicitly instantiate DECL. */
17683 void
17685 {
17690 /* An error occurred, for which grokdeclarator has already issued
17691 an appropriate message. */
17694 {
17697 }
17699 {
17700 /* There is an asymmetry here in the way VAR_DECLs and
17701 FUNCTION_DECLs are handled by grokdeclarator. In the case of
17702 the latter, the DECL we get back will be marked as a
17703 template instantiation, and the appropriate
17704 DECL_TEMPLATE_INFO will be set up. This does not happen for
17705 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
17706 should handle VAR_DECLs as it currently handles
17707 FUNCTION_DECLs. */
17709 {
17712 }
17715 {
17718 }
17720 {
17725 }
17726 }
17728 {
17731 }
17732 else
17735 /* Check for various error cases. Note that if the explicit
17736 instantiation is valid the RESULT will currently be marked as an
17737 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
17738 until we get here. */
17741 {
17742 /* DR 259 [temp.spec].
17744 Both an explicit instantiation and a declaration of an explicit
17745 specialization shall not appear in a program unless the explicit
17746 instantiation follows a declaration of the explicit specialization.
17748 For a given set of template parameters, if an explicit
17749 instantiation of a template appears after a declaration of an
17750 explicit specialization for that template, the explicit
17751 instantiation has no effect. */
17753 }
17755 {
17756 /* [temp.spec]
17758 No program shall explicitly instantiate any template more
17759 than once.
17761 We check DECL_NOT_REALLY_EXTERN so as not to complain when
17762 the first instantiation was `extern' and the second is not,
17763 and EXTERN_P for the opposite case. */
17766 /* If an "extern" explicit instantiation follows an ordinary
17767 explicit instantiation, the template is instantiated. */
17770 }
17772 {
17775 }
17777 {
17780 }
17783 ;
17785 {
17788 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
17791 }
17792 else
17800 }
17802 static void
17804 {
17810 {
17813 }
17814 }
17816 /* Called from do_type_instantiation through binding_table_foreach to
17817 do recursive instantiation for the type bound in ENTRY. */
17818 static void
17820 {
17826 }
17828 /* Called from do_type_instantiation to instantiate a member
17829 (a member function or a static member variable) of an
17830 explicitly instantiated class template. */
17831 static void
17833 {
17838 }
17840 /* Perform an explicit instantiation of template class T. STORAGE, if
17841 non-null, is the RID for extern, inline or static. COMPLAIN is
17842 nonzero if this is called from the parser, zero if called recursively,
17843 since the standard is unclear (as detailed below). */
17845 void
17847 {
17857 {
17858 tree tmpl =
17862 else
17865 }
17870 {
17873 t);
17875 }
17878 {
17880 {
17882 {
17885 "ISO C++ 1998 forbids the use of %<extern%> on "
17887 }
17888 else
17890 "ISO C++ forbids the use of %qE"
17892 }
17900 else
17901 {
17903 storage);
17905 }
17906 }
17909 {
17910 /* DR 259 [temp.spec].
17912 Both an explicit instantiation and a declaration of an explicit
17913 specialization shall not appear in a program unless the explicit
17914 instantiation follows a declaration of the explicit specialization.
17916 For a given set of template parameters, if an explicit
17917 instantiation of a template appears after a declaration of an
17918 explicit specialization for that template, the explicit
17919 instantiation has no effect. */
17921 }
17923 {
17924 /* [temp.spec]
17926 No program shall explicitly instantiate any template more
17927 than once.
17929 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
17930 instantiation was `extern'. If EXTERN_P then the second is.
17931 These cases are OK. */
17938 /* If we've already instantiated the template, just return now. */
17941 }
17949 {
17950 tree tmp;
17952 /* In contrast to implicit instantiation, where only the
17953 declarations, and not the definitions, of members are
17954 instantiated, we have here:
17956 [temp.explicit]
17958 The explicit instantiation of a class template specialization
17959 implies the instantiation of all of its members not
17960 previously explicitly specialized in the translation unit
17961 containing the explicit instantiation.
17963 Of course, we can't instantiate member template classes, since
17964 we don't have any arguments for them. Note that the standard
17965 is unclear on whether the instantiation of the members are
17966 *explicit* instantiations or not. However, the most natural
17967 interpretation is that it should be an explicit instantiation. */
17982 }
17983 }
17985 /* Given a function DECL, which is a specialization of TMPL, modify
17986 DECL to be a re-instantiation of TMPL with the same template
17987 arguments. TMPL should be the template into which tsubst'ing
17988 should occur for DECL, not the most general template.
17990 One reason for doing this is a scenario like this:
17992 template <class T>
17993 void f(const T&, int i);
17995 void g() { f(3, 7); }
17997 template <class T>
17998 void f(const T& t, const int i) { }
18000 Note that when the template is first instantiated, with
18001 instantiate_template, the resulting DECL will have no name for the
18002 first parameter, and the wrong type for the second. So, when we go
18003 to instantiate the DECL, we regenerate it. */
18005 static void
18007 {
18008 /* The arguments used to instantiate DECL, from the most general
18009 template. */
18010 tree args;
18011 tree code_pattern;
18016 /* Make sure that we can see identifiers, and compute access
18017 correctly. */
18021 {
18022 tree decl_parm;
18023 tree pattern_parm;
18024 tree specs;
18038 specs);
18040 /* Merge parameter declarations. */
18043 pattern_parm
18047 {
18048 tree parm_type;
18049 tree attributes;
18054 NULL_TREE);
18060 {
18063 }
18066 }
18067 /* Merge any parameters that match with the function parameter
18068 pack. */
18070 {
18072 tree expanded_types;
18073 /* Expand the TYPE_PACK_EXPANSION that provides the types for
18074 the parameters in this function parameter pack. */
18079 {
18080 tree parm_type;
18081 tree attributes;
18084 /* Rename the parameter to include the index. */
18093 {
18096 }
18098 }
18099 }
18100 /* Merge additional specifiers from the CODE_PATTERN. */
18104 }
18106 {
18114 }
18115 else
18119 }
18121 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
18122 substituted to get DECL. */
18124 tree
18126 {
18129 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
18130 for the instantiation. This is not always the most general
18131 template. Consider, for example:
18133 template <class T>
18134 struct S { template <class U> void f();
18135 template <> void f<int>(); };
18137 and an instantiation of S<double>::f<int>. We want TD to be the
18138 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
18140 more general template. */
18142 /* We must also deal with friend templates. Given:
18144 template <class T> struct S {
18145 template <class U> friend void f() {};
18146 };
18148 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
18149 so far as the language is concerned, but that's still
18150 where we get the pattern for the instantiation from. On
18151 other hand, if the definition comes outside the class, say:
18153 template <class T> struct S {
18154 template <class U> friend void f();
18155 };
18156 template <class U> friend void f() {}
18158 we don't need to look any further. That's what the check for
18159 DECL_INITIAL is for. */
18163 {
18164 /* The present template, TD, should not be a definition. If it
18165 were a definition, we should be using it! Note that we
18166 cannot restructure the loop to just keep going until we find
18167 a template with a definition, since that might go too far if
18168 a specialization was declared, but not defined. */
18172 /* Fetch the more general template. */
18174 }
18177 }
18179 /* Returns true if we need to instantiate this template instance even if we
18180 know we aren't going to emit it.. */
18182 bool
18184 {
18185 /* We always instantiate inline functions so that we can inline them. An
18186 explicit instantiation declaration prohibits implicit instantiation of
18187 non-inline functions. With high levels of optimization, we would
18188 normally inline non-inline functions -- but we're not allowed to do
18189 that for "extern template" functions. Therefore, we check
18190 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
18194 /* And we need to instantiate static data members so that
18195 their initializers are available in integral constant
18196 expressions. */
18199 }
18201 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
18202 instantiate it now, modifying TREE_TYPE (fn). */
18204 void
18206 {
18220 {
18222 {
18235 }
18236 else
18238 }
18239 else
18240 {
18241 /* This is an implicitly declared function, so NOEX is a list of
18242 other functions to evaluate and merge. */
18243 tree elt;
18246 {
18248 tree subspec;
18252 }
18253 }
18258 {
18261 else
18263 }
18264 }
18266 /* Produce the definition of D, a _DECL generated from a template. If
18267 DEFER_OK is nonzero, then we don't have to actually do the
18268 instantiation now; we just have to do it sometime. Normally it is
18269 an error if this is an explicit instantiation but D is undefined.
18270 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
18271 explicitly instantiated class template. */
18273 tree
18276 {
18278 tree gen_args;
18279 tree args;
18280 tree td;
18281 tree code_pattern;
18282 tree spec;
18283 tree gen_tmpl;
18287 tree fn_context;
18290 /* This function should only be used to instantiate templates for
18291 functions and static member variables. */
18295 /* Variables are never deferred; if instantiation is required, they
18296 are instantiated right away. That allows for better code in the
18297 case that an expression refers to the value of the variable --
18298 if the variable has a constant value the referring expression can
18299 take advantage of that fact. */
18304 /* Don't instantiate cloned functions. Instead, instantiate the
18305 functions they cloned. */
18313 /* D has already been instantiated or explicitly specialized, so
18314 there's nothing for us to do here.
18316 It might seem reasonable to check whether or not D is an explicit
18317 instantiation, and, if so, stop here. But when an explicit
18318 instantiation is deferred until the end of the compilation,
18319 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
18320 the instantiation. */
18323 /* Check to see whether we know that this template will be
18324 instantiated in some other file, as with "extern template"
18325 extension. */
18328 /* In general, we do not instantiate such templates. */
18336 /* We should already have the extra args. */
18339 /* And what's in the hash table should match D. */
18343 /* This needs to happen before any tsubsting. */
18349 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
18350 for the instantiation. */
18354 /* We should never be trying to instantiate a member of a class
18355 template or partial specialization. */
18360 /* In the case of a friend template whose definition is provided
18361 outside the class, we may have too many arguments. Drop the
18362 ones we don't need. The same is true for specializations. */
18363 args = get_innermost_template_args
18365 else
18371 else
18374 /* We may be in the middle of deferred access check. Disable it now. */
18377 /* Unless an explicit instantiation directive has already determined
18378 the linkage of D, remember that a definition is available for
18379 this entity. */
18389 /* If D is a member of an explicitly instantiated class template,
18390 and no definition is available, treat it like an implicit
18391 instantiation. */
18394 {
18395 /* Leave linkage flags alone on instantiations with anonymous
18396 visibility. */
18398 {
18401 }
18403 }
18408 /* Defer all other templates, unless we have been explicitly
18409 forbidden from doing so. */
18411 template. */
18412 ! pattern_defined
18413 /* If it's OK to postpone instantiation, do so. */
18414 || defer_ok
18415 /* If this is a static data member that will be defined
18416 elsewhere, we don't want to instantiate the entire data
18417 member, but we do want to instantiate the initializer so that
18418 we can substitute that elsewhere. */
18420 {
18421 /* The definition of the static data member is now required so
18422 we must substitute the initializer. */
18426 {
18427 tree ns;
18428 tree init;
18435 args,
18438 /* Make sure the initializer is still constant, in case of
18439 circular dependency (template/instantiate6.C). */
18440 const_init
18444 LOOKUP_ONLYCONVERTING);
18447 }
18449 /* We restore the source position here because it's used by
18450 add_pending_template. */
18456 /* [temp.explicit]
18458 The definition of a non-exported function template, a
18459 non-exported member function template, or a non-exported
18460 member function or static data member of a class template
18461 shall be present in every translation unit in which it is
18462 explicitly instantiated. */
18466 /* If we're in unevaluated context, we just wanted to get the
18467 constant value; this isn't an odr use, so don't queue
18468 a full instantiation. */
18471 /* ??? Historically, we have instantiated inline functions, even
18472 when marked as "extern template". */
18476 }
18477 /* Tell the repository that D is available in this translation unit
18478 -- and see if it is supposed to be instantiated here. */
18480 {
18481 /* In a PCH file, despite the fact that the repository hasn't
18482 requested instantiation in the PCH it is still possible that
18483 an instantiation will be required in a file that includes the
18484 PCH. */
18487 /* Instantiate inline functions so that the inliner can do its
18488 job, even though we'll not be emitting a copy of this
18489 function. */
18492 }
18501 /* Mark D as instantiated so that recursive calls to
18502 instantiate_decl do not try to instantiate it again. */
18505 /* Regenerate the declaration in case the template has been modified
18506 by a subsequent redeclaration. */
18509 /* We already set the file and line above. Reset them now in case
18510 they changed as a result of calling regenerate_decl_from_template. */
18514 {
18515 tree init;
18518 /* Clear out DECL_RTL; whatever was there before may not be right
18519 since we've reset the type of the declaration. */
18523 /* The initializer is placed in DECL_INITIAL by
18524 regenerate_decl_from_template so we don't need to
18525 push/pop_access_scope again here. Pull it out so that
18526 cp_finish_decl can process it. */
18531 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
18532 initializer. That function will defer actual emission until
18533 we have a chance to determine linkage. */
18536 /* Enter the scope of D so that access-checking works correctly. */
18541 }
18545 {
18547 tree subst_decl;
18548 tree tmpl_parm;
18549 tree spec_parm;
18551 /* Save away the current list, in case we are instantiating one
18552 template from within the body of another. */
18555 /* Set up the list of local specializations. */
18558 /* Set up context. */
18561 /* Some typedefs referenced from within the template code need to be
18562 access checked at template instantiation time, i.e now. These
18563 types were added to the template at parsing time. Let's get those
18564 and perform the access checks then. */
18566 gen_args);
18568 /* Create substitution entries for the parameters. */
18573 {
18577 }
18579 {
18581 {
18584 }
18585 else
18586 {
18587 /* Register the (value) argument pack as a specialization of
18588 TMPL_PARM, then move on. */
18591 }
18592 }
18595 /* Substitute into the body of the function. */
18600 /* Set the current input_location to the end of the function
18601 so that finish_function knows where we are. */
18604 /* We don't need the local specializations any more. */
18608 /* Finish the function. */
18611 }
18613 /* We're not deferring instantiation any more. */
18621 out:
18629 }
18631 /* Run through the list of templates that we wish we could
18632 instantiate, and instantiate any we can. RETRIES is the
18633 number of times we retry pending template instantiation. */
18635 void
18637 {
18641 /* Instantiating templates may trigger vtable generation. This in turn
18642 may require further template instantiations. We place a limit here
18643 to avoid infinite loop. */
18645 {
18649 " instantiating %q+D, possibly from virtual table generation"
18653 /* Pretend that we defined it. */
18656 }
18658 do
18659 {
18664 {
18669 {
18670 tree fn;
18673 {
18677 fn;
18685 }
18688 }
18689 else
18690 {
18693 {
18694 instantiation
18700 }
18704 }
18707 /* If INSTANTIATION has been instantiated, then we don't
18708 need to consider it again in the future. */
18710 else
18711 {
18714 }
18717 }
18719 }
18723 }
18725 /* Substitute ARGVEC into T, which is a list of initializers for
18726 either base class or a non-static data member. The TREE_PURPOSEs
18727 are DECLs, and the TREE_VALUEs are the initializer values. Used by
18728 instantiate_decl. */
18730 static tree
18732 {
18736 {
18737 tree decl;
18738 tree init;
18744 {
18745 tree expr;
18746 tree arg;
18748 /* Expand the base class expansion type into separate base
18749 classes. */
18751 tf_warning_or_error,
18752 NULL_TREE);
18756 /* We'll be building separate TREE_LISTs of arguments for
18757 each base. */
18763 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
18764 expand each argument in the TREE_VALUE of t. */
18771 /* VOID_TYPE_NODE is used to indicate
18772 value-initialization. */
18773 {
18776 }
18777 else
18778 {
18779 /* Substitute parameter packs into each argument in the
18780 TREE_LIST. */
18783 {
18784 tree expanded_exprs;
18786 /* Expand the argument. */
18788 expanded_exprs
18790 tf_warning_or_error,
18791 NULL_TREE);
18795 /* Prepend each of the expanded expressions to the
18796 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
18798 {
18803 }
18804 }
18807 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
18808 since we built them backwards. */
18810 {
18813 }
18814 }
18815 }
18818 {
18820 {
18824 }
18825 else
18826 {
18827 tree tmp;
18842 /* If we had an initializer but it instantiated to nothing,
18843 value-initialize the object. This will only occur when
18844 the initializer was a pack expansion where the parameter
18845 packs used in that expansion were of length zero. */
18848 }
18851 {
18855 }
18856 }
18857 }
18859 }
18861 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
18863 static void
18865 {
18870 else
18872 }
18874 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
18875 is the instantiation (which should have been created with
18876 start_enum) and ARGS are the template arguments to use. */
18878 static void
18880 {
18881 tree e;
18887 {
18888 tree value;
18889 tree decl;
18892 /* Note that in a template enum, the TREE_VALUE is the
18893 CONST_DECL, not the corresponding INTEGER_CST. */
18898 /* Give this enumeration constant the correct access. */
18901 /* Actually build the enumerator itself. */
18902 build_enumerator
18904 }
18914 }
18916 /* DECL is a FUNCTION_DECL that is a template specialization. Return
18917 its type -- but without substituting the innermost set of template
18918 arguments. So, innermost set of template parameters will appear in
18919 the type. */
18921 tree
18923 {
18924 tree fn_type;
18925 tree tmpl;
18926 tree targs;
18927 tree tparms;
18935 /* There should be as many levels of arguments as there are levels
18936 of parameters. */
18942 /* No substitution is necessary. */
18943 ;
18944 else
18945 {
18947 tree partial_args;
18949 /* Replace the innermost level of the TARGS with NULL_TREEs to
18950 let tsubst know not to substitute for those parameters. */
18959 /* Make sure that we can see identifiers, and compute access
18960 correctly. */
18964 /* Now, do the (partial) substitution to figure out the
18965 appropriate function type. */
18969 /* Substitute into the template parameters to obtain the real
18970 innermost set of parameters. This step is important if the
18971 innermost set of template parameters contains value
18972 parameters whose types depend on outer template parameters. */
18977 }
18980 }
18982 /* Return truthvalue if we're processing a template different from
18983 the last one involved in diagnostics. */
18984 int
18986 {
18988 }
18990 /* Remember current template involved in diagnostics. */
18991 void
18993 {
18995 }
18999 {
19001 }
19003 /* [temp.param] Check that template non-type parm TYPE is of an allowable
19004 type. Return zero for ok, nonzero for disallowed. Issue error and
19005 warning messages under control of COMPLAIN. */
19007 static int
19009 {
19026 {
19029 else
19031 type);
19032 }
19034 }
19036 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
19037 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
19039 static bool
19041 {
19042 tree scope;
19044 /* [temp.dep.type]
19046 A type is dependent if it is:
19048 -- a template parameter. Template template parameters are types
19049 for us (since TYPE_P holds true for them) so we handle
19050 them here. */
19054 /* -- a qualified-id with a nested-name-specifier which contains a
19055 class-name that names a dependent type or whose unqualified-id
19056 names a dependent type. */
19059 /* -- a cv-qualified type where the cv-unqualified type is
19060 dependent. */
19062 /* -- a compound type constructed from any dependent type. */
19072 {
19073 tree arg_type;
19078 arg_type;
19083 }
19084 /* -- an array type constructed from any dependent type or whose
19085 size is specified by a constant expression that is
19086 value-dependent.
19088 We checked for type- and value-dependence of the bounds in
19089 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
19091 {
19096 }
19098 /* -- a template-id in which either the template name is a template
19099 parameter ... */
19102 /* ... or any of the template arguments is a dependent type or
19103 an expression that is type-dependent or value-dependent. */
19105 && (any_dependent_template_arguments_p
19109 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
19110 dependent; if the argument of the `typeof' expression is not
19111 type-dependent, then it should already been have resolved. */
19117 /* A template argument pack is dependent if any of its packed
19118 arguments are. */
19120 {
19126 }
19128 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
19129 be template parameters. */
19133 /* The standard does not specifically mention types that are local
19134 to template functions or local classes, but they should be
19135 considered dependent too. For example:
19137 template <int I> void f() {
19138 enum E { a = I };
19139 S<sizeof (E)> s;
19140 }
19142 The size of `E' cannot be known until the value of `I' has been
19143 determined. Therefore, `E' must be considered dependent. */
19147 /* Don't use type_dependent_expression_p here, as it can lead
19148 to infinite recursion trying to determine whether a lambda
19149 nested in a lambda is dependent (c++/47687). */
19153 && (any_dependent_template_arguments_p
19157 /* Other types are non-dependent. */
19159 }
19161 /* Returns TRUE if TYPE is dependent, in the sense of
19162 [temp.dep.type]. Note that a NULL type is considered dependent. */
19164 bool
19166 {
19167 /* If there are no template parameters in scope, then there can't be
19168 any dependent types. */
19170 {
19171 /* If we are not processing a template, then nobody should be
19172 providing us with a dependent type. */
19176 }
19178 /* If the type is NULL, we have not computed a type for the entity
19179 in question; in that case, the type is dependent. */
19183 /* Erroneous types can be considered non-dependent. */
19187 /* If we have not already computed the appropriate value for TYPE,
19188 do so now. */
19190 {
19193 }
19196 }
19198 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
19199 lookup. In other words, a dependent type that is not the current
19200 instantiation. */
19202 bool
19204 {
19207 }
19209 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
19210 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
19211 expression. */
19213 /* Note that this predicate is not appropriate for general expressions;
19214 only constant expressions (that satisfy potential_constant_expression)
19215 can be tested for value dependence. */
19217 bool
19219 {
19223 /* A name declared with a dependent type. */
19228 {
19230 /* A name that has not been looked up -- must be dependent. */
19234 /* A non-type template parm. */
19238 /* A non-type template parm. */
19244 /* A constant with literal type and is initialized
19245 with an expression that is value-dependent.
19247 Note that a non-dependent parenthesized initializer will have
19248 already been replaced with its constant value, so if we see
19249 a TREE_LIST it must be dependent. */
19262 /* These expressions are value-dependent if the type to which
19263 the cast occurs is dependent or the expression being casted
19264 is value-dependent. */
19265 {
19271 /* A functional cast has a list of operands. */
19274 {
19275 /* If there are no operands, it must be an expression such
19276 as "int()". This should not happen for aggregate types
19277 because it would form non-constant expressions. */
19282 }
19288 }
19293 /* A `sizeof' expression is value-dependent if the operand is
19294 type-dependent or is a pack expansion. */
19303 /* An 'encode' expression is value-dependent if the operand is
19304 type-dependent. */
19313 /* instantiation_dependent_r treats this as dependent so that we
19314 check access at instantiation time, and all instantiation-dependent
19315 expressions should also be considered value-dependent. */
19323 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
19324 is value-dependent. */
19325 {
19334 }
19337 {
19341 }
19352 {
19356 }
19359 {
19366 {
19368 /* In a call to a constexpr member function, look through the
19369 implicit ADDR_EXPR on the object argument so that it doesn't
19370 cause the call to be considered value-dependent. We also
19371 look through it in potential_constant_expression. */
19378 }
19380 }
19383 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
19384 type-dependent. */
19388 {
19390 tree val;
19395 }
19398 /* Treat a GNU statement expression as dependent to avoid crashing
19399 under fold_non_dependent_expr; it can't be constant. */
19403 /* A constant expression is value-dependent if any subexpression is
19404 value-dependent. */
19406 {
19413 {
19417 {
19420 /* In some cases, some of the operands may be missing.l
19421 (For example, in the case of PREDECREMENT_EXPR, the
19422 amount to increment by may be missing.) That doesn't
19423 make the expression dependent. */
19426 }
19427 }
19431 }
19433 }
19435 /* The expression is not value-dependent. */
19437 }
19439 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
19440 [temp.dep.expr]. Note that an expression with no type is
19441 considered dependent. Other parts of the compiler arrange for an
19442 expression with type-dependent subexpressions to have no type, so
19443 this function doesn't have to be fully recursive. */
19445 bool
19447 {
19454 /* An unresolved name is always dependent. */
19459 /* Some expression forms are never type-dependent. */
19472 /* The types of these expressions depends only on the type to which
19473 the cast occurs. */
19482 /* The types of these expressions depends only on the type created
19483 by the expression. */
19486 {
19487 /* For NEW_EXPR tree nodes created inside a template, either
19488 the object type itself or a TREE_LIST may appear as the
19489 operand 1. */
19492 /* This is an array type. We need to check array dimensions
19493 as well. */
19495 || value_dependent_expression_p
19497 else
19499 }
19502 {
19506 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
19507 contains an identifier associated by name lookup with one or more
19508 declarations declared with a dependent type, or...a
19509 nested-name-specifier or qualified-id that names a member of an
19510 unknown specialization. */
19513 }
19518 && (any_dependent_template_arguments_p
19530 {
19531 tree elt;
19535 {
19538 }
19540 }
19542 /* A static data member of the current instantiation with incomplete
19543 array type is type-dependent, as the definition and specializations
19544 can have different bounds. */
19552 {
19557 {
19563 }
19564 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
19572 {
19577 }
19582 {
19586 }
19588 }
19593 }
19595 /* walk_tree callback function for instantiation_dependent_expression_p,
19596 below. Returns non-zero if a dependent subexpression is found. */
19598 static tree
19601 {
19603 {
19604 /* We don't have to worry about decltype currently because decltype
19605 of an instantiation-dependent expr is a dependent type. This
19606 might change depending on the resolution of DR 1172. */
19609 }
19612 {
19613 /* Don't treat an argument list as dependent just because it has no
19614 TREE_TYPE. */
19622 /* Handle expressions with type operands. */
19628 {
19631 {
19636 else
19637 {
19640 }
19641 }
19643 }
19647 /* In a template, finish_class_member_access_expr creates a
19648 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
19649 type-dependent, so that we can check access control at
19650 instantiation time (PR 42277). See also Core issue 1273. */
19655 /* Similarly, finish_qualified_id_expr builds up a SCOPE_REF in a
19656 template so that we can check access at instantiation time even
19657 though we know which member it resolves to. */
19662 }
19666 else
19668 }
19670 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
19671 sense defined by the ABI:
19673 "An expression is instantiation-dependent if it is type-dependent
19674 or value-dependent, or it has a subexpression that is type-dependent
19675 or value-dependent." */
19677 bool
19679 {
19680 tree result;
19691 }
19693 /* Like type_dependent_expression_p, but it also works while not processing
19694 a template definition, i.e. during substitution or mangling. */
19696 bool
19698 {
19704 }
19706 /* Returns TRUE if ARGS contains a type-dependent expression. */
19708 bool
19710 {
19712 tree arg;
19715 {
19718 }
19720 }
19722 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
19723 expressions) contains any type-dependent expressions. */
19725 bool
19727 {
19733 }
19735 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
19736 expressions) contains any value-dependent expressions. */
19738 bool
19740 {
19746 }
19748 /* Returns TRUE if the ARG (a template argument) is dependent. */
19750 bool
19752 {
19756 /* Assume a template argument that was wrongly written by the user
19757 is dependent. This is consistent with what
19758 any_dependent_template_arguments_p [that calls this function]
19759 does. */
19770 {
19774 {
19777 }
19780 }
19783 else
19786 }
19788 /* Returns true if ARGS (a collection of template arguments) contains
19789 any types that require structural equality testing. */
19791 bool
19793 {
19803 {
19806 {
19812 {
19813 /* Look inside the argument pack. */
19816 }
19819 {
19833 }
19834 }
19835 }
19838 }
19840 /* Returns true if ARGS (a collection of template arguments) contains
19841 any dependent arguments. */
19843 bool
19845 {
19855 {
19860 }
19863 }
19865 /* Returns TRUE if the template TMPL is dependent. */
19867 bool
19869 {
19871 {
19873 {
19877 }
19879 }
19881 /* Template template parameters are dependent. */
19885 /* So are names that have not been looked up. */
19889 /* So are member templates of dependent classes. */
19893 }
19895 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
19897 bool
19899 {
19902 }
19904 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
19905 is dependent. */
19907 bool
19909 {
19916 {
19937 {
19941 }
19945 {
19949 {
19954 }
19955 }
19956 }
19959 }
19961 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
19962 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
19963 no such TYPE can be found. Note that this function peers inside
19964 uninstantiated templates and therefore should be used only in
19965 extremely limited situations. ONLY_CURRENT_P restricts this
19966 peering to the currently open classes hierarchy (which is required
19967 when comparing types). */
19969 tree
19971 {
19972 tree scope;
19973 tree name;
19974 tree decl;
19976 tree pushed_scope;
19977 tree result;
19982 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
19983 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
19984 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
19985 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
19986 identifier of the TYPENAME_TYPE anymore.
19987 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
19988 TYPENAME_TYPE instead, we avoid messing up with a possible
19989 typedef variant case. */
19992 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
19993 it first before we can figure out what NAME refers to. */
19996 /* If we don't know what SCOPE refers to, then we cannot resolve the
19997 TYPENAME_TYPE. */
20000 /* If the SCOPE is a template type parameter, we have no way of
20001 resolving the name. */
20004 /* If the SCOPE is not the current instantiation, there's no reason
20005 to look inside it. */
20008 /* If this is a typedef, we don't want to look inside (c++/11987). */
20011 /* If SCOPE isn't the template itself, it will not have a valid
20012 TYPE_FIELDS list. */
20014 /* scope is either the template itself or a compatible instantiation
20015 like X<T>, so look up the name in the original template. */
20017 else
20018 /* scope is a partial instantiation, so we can't do the lookup or we
20019 will lose the template arguments. */
20021 /* Enter the SCOPE so that name lookup will be resolved as if we
20022 were in the class definition. In particular, SCOPE will no
20023 longer be considered a dependent type. */
20025 /* Look up the declaration. */
20027 tf_warning_or_error);
20031 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
20032 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
20037 {
20041 }
20044 {
20045 tree tmpl;
20046 tree args;
20047 /* Obtain the template and the arguments. */
20050 /* Instantiate the template. */
20056 }
20058 /* Leave the SCOPE. */
20062 /* If we failed to resolve it, return the original typename. */
20066 /* If lookup found a typename type, resolve that too. */
20068 {
20069 /* Ill-formed programs can cause infinite recursion here, so we
20070 must catch that. */
20074 }
20076 /* Qualify the resulting type. */
20082 }
20084 /* EXPR is an expression which is not type-dependent. Return a proxy
20085 for EXPR that can be used to compute the types of larger
20086 expressions containing EXPR. */
20088 tree
20090 {
20091 tree inner_expr;
20093 #ifdef ENABLE_CHECKING
20094 /* Try to get a constant value for all non-type-dependent expressions in
20095 order to expose bugs in *_dependent_expression_p and constexpr. */
20098 #endif
20100 /* Preserve OVERLOADs; the functions must be available to resolve
20101 types. */
20112 /* There is no need to return a proxy for a variable. */
20115 /* Preserve string constants; conversions from string constants to
20116 "char *" are allowed, even though normally a "const char *"
20117 cannot be used to initialize a "char *". */
20120 /* Preserve arithmetic constants, as an optimization -- there is no
20121 reason to create a new node. */
20124 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
20125 There is at least one place where we want to know that a
20126 particular expression is a throw-expression: when checking a ?:
20127 expression, there are special rules if the second or third
20128 argument is a throw-expression. */
20132 /* Don't wrap an initializer list, we need to be able to look inside. */
20136 /* Don't wrap a dummy object, we need to be able to test for it. */
20155 /* If the type is unknown, it can't really be non-dependent */
20158 /* Otherwise, build a NON_DEPENDENT_EXPR. */
20160 }
20162 /* ARGS is a vector of expressions as arguments to a function call.
20163 Replace the arguments with equivalent non-dependent expressions.
20164 This modifies ARGS in place. */
20166 void
20168 {
20170 tree arg;
20173 {
20177 }
20178 }
20180 /* Returns a type which represents 'auto'. We use a TEMPLATE_TYPE_PARM
20181 with a level one deeper than the actual template parms. */
20183 tree
20185 {
20198 }
20200 /* Given type ARG, return std::initializer_list<ARG>. */
20202 static tree
20204 {
20205 tree std_init_list = namespace_binding
20207 tree argvec;
20209 {
20213 }
20218 }
20220 /* Replace auto in TYPE with std::initializer_list<auto>. */
20222 static tree
20224 {
20231 }
20233 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
20234 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
20236 tree
20238 {
20247 /* Defining a subset of type-dependent expressions that we can deduce
20248 from ahead of time isn't worth the trouble. */
20251 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
20252 with either a new invented type template parameter U or, if the
20253 initializer is a braced-init-list (8.5.4), with
20254 std::initializer_list<U>. */
20270 {
20272 /* Try again at instantiation time. */
20275 /* If type is error_mark_node a diagnostic must have been
20276 emitted by now. Also, having a mention to '<type error>'
20277 in the diagnostic is not really useful to the user. */
20278 {
20282 else
20284 }
20286 }
20288 /* If the list of declarators contains more than one declarator, the type
20289 of each declared variable is determined as described above. If the
20290 type deduced for the template parameter U is not the same in each
20291 deduction, the program is ill-formed. */
20294 {
20300 else
20304 }
20310 }
20312 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
20313 result. */
20315 tree
20317 {
20318 tree argvec;
20325 /* For a late-specified return type in a template type-parameter, we
20326 need to add a dummy argument level for its parmlist. */
20327 argvec = add_to_template_args
20332 }
20334 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto'. */
20336 bool
20338 {
20342 else
20344 }
20346 /* Returns true iff TYPE contains a use of 'auto'. Since auto can only
20347 appear as a type-specifier for the declaration in question, we don't
20348 have to look through the whole type. */
20350 tree
20352 {
20369 }
20371 /* For a given template T, return the vector of typedefs referenced
20372 in T for which access check is needed at T instantiation time.
20373 T is either a FUNCTION_DECL or a RECORD_TYPE.
20374 Those typedefs were added to T by the function
20375 append_type_to_template_for_access_check. */
20379 {
20380 tree ti;
20391 {
20396 }
20399 }
20401 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
20402 tied to T. That list of typedefs will be access checked at
20403 T instantiation time.
20404 T is either a FUNCTION_DECL or a RECORD_TYPE.
20405 TYPE_DECL is a TYPE_DECL node representing a typedef.
20406 SCOPE is the scope through which TYPE_DECL is accessed.
20407 LOCATION is the location of the usage point of TYPE_DECL.
20409 This function is a subroutine of
20410 append_type_to_template_for_access_check. */
20412 static void
20414 tree type_decl,
20415 tree scope,
20416 location_t location)
20417 {
20418 qualified_typedef_usage_t typedef_usage;
20419 tree ti;
20426 && type_decl
20441 typedef_usage);
20442 }
20444 /* Append TYPE_DECL to the template TEMPL.
20445 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
20446 At TEMPL instanciation time, TYPE_DECL will be checked to see
20447 if it can be accessed through SCOPE.
20448 LOCATION is the location of the usage point of TYPE_DECL.
20450 e.g. consider the following code snippet:
20452 class C
20453 {
20454 typedef int myint;
20455 };
20457 template<class U> struct S
20458 {
20459 C::myint mi; // <-- usage point of the typedef C::myint
20460 };
20462 S<char> s;
20464 At S<char> instantiation time, we need to check the access of C::myint
20465 In other words, we need to check the access of the myint typedef through
20466 the C scope. For that purpose, this function will add the myint typedef
20467 and the scope C through which its being accessed to a list of typedefs
20468 tied to the template S. That list will be walked at template instantiation
20469 time and access check performed on each typedefs it contains.
20470 Note that this particular code snippet should yield an error because
20471 myint is private to C. */
20473 void
20475 tree type_decl,
20476 tree scope,
20477 location_t location)
20478 {
20484 /* Make sure we don't append the type to the template twice. */
20493 }
20495 /* Set up the hash tables for template instantiations. */
20497 void
20499 {
20501 hash_specialization,
20502 eq_specializations,
20503 ggc_free);
20505 hash_specialization,
20506 eq_specializations,
20507 ggc_free);
20508 }
20510 /* Print stats about the template hash tables for -fstats. */
20512 void
20514 {
20523 }