| blob | ed4fe726c205aa22673407a9b8c379fc8ee511c6 |
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
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". */
49 /* The type of functions taking a tree, and some additional data, and
50 returning an int. */
53 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
54 instantiations have been deferred, either because their definitions
55 were not yet available, or because we were putting off doing the work. */
59 };
74 /* Live only within one (recursive) call to tsubst_expr. We use
75 this to pass the statement expression node from the STMT_EXPR
76 to the EXPR_STMT that is its result. */
79 /* A map from local variable declarations in the body of the template
80 presently being instantiated to the corresponding instantiated
81 local variables. */
85 {
86 tree tmpl;
87 tree args;
88 tree spec;
92 htab_t decl_specializations;
95 htab_t type_specializations;
97 /* Contains canonical template parameter types. The vector is indexed by
98 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
99 TREE_LIST, whose TREE_VALUEs contain the canonical template
100 parameters of various types and levels. */
103 #define UNIFY_ALLOW_NONE 0
104 #define UNIFY_ALLOW_MORE_CV_QUAL 1
105 #define UNIFY_ALLOW_LESS_CV_QUAL 2
106 #define UNIFY_ALLOW_DERIVED 4
107 #define UNIFY_ALLOW_INTEGER 8
108 #define UNIFY_ALLOW_OUTER_LEVEL 16
109 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
110 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
113 tbr_incomplete_type,
114 tbr_ambiguous_baseclass,
115 tbr_success
116 };
139 tree);
202 location_t);
211 /* Make the current scope suitable for access checking when we are
212 processing T. T can be FUNCTION_DECL for instantiated function
213 template, or VAR_DECL for static member variable (need by
214 instantiate_decl). */
216 static void
218 {
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 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 {
818 /* This is for ordinary explicit specialization and partial
819 specialization of a template class such as:
821 template <> class C<int>;
823 or:
825 template <class T> class C<T*>;
827 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
831 {
835 {
839 }
840 }
843 }
849 {
850 /* This is for an explicit specialization of member class
851 template according to [temp.expl.spec/18]:
853 template <> template <class U> class C<int>::D;
855 The context `C<int>' must be an implicit instantiation.
856 Otherwise this is just a member class template declared
857 earlier like:
859 template <> class C<int> { template <class U> class D; };
860 template <> template <class U> class C<int>::D;
862 In the first case, `C<int>::D' is a specialization of `C<T>::D'
863 while in the second case, `C<int>::D' is a primary template
864 and `C<T>::D' may not exist. */
868 {
869 tree t;
874 {
877 }
879 /* Check for invalid specialization after instantiation:
881 template <> template <> class C<int>::D<int>;
882 template <> template <class U> class C<int>::D; */
886 {
889 {
890 /* We already have a full specialization of this partial
891 instantiation. Reassign it to the new member
892 specialization template. */
893 spec_entry elt;
909 }
911 /* But if we've had an implicit instantiation, that's a
912 problem ([temp.expl.spec]/6). */
915 }
917 /* Mark TYPE as a specialization. And as a result, we only
918 have one level of template argument for the innermost
919 class template. */
923 }
924 }
926 {
927 /* Someday C++0x may allow for enum template specialization. */
932 else
933 {
936 }
937 }
940 }
942 /* Returns nonzero if we can optimize the retrieval of specializations
943 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
944 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
948 {
951 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
952 parameter. */
954 /* The optimized lookup depends on the fact that the
955 template arguments for the member function template apply
956 purely to the containing class, which is not true if the
957 containing class is an explicit or partial
958 specialization. */
962 /* It is possible to have a template that is not a member
963 template and is not a member of a template class:
965 template <typename T>
966 struct S { friend A::f(); };
968 Here, the friend function is a template, but the context does
969 not have template information. The optimized lookup relies
970 on having ARGS be the template arguments for both the class
971 and the function template. */
973 }
975 /* Retrieve the specialization (in the sense of [temp.spec] - a
976 specialization is either an instantiation or an explicit
977 specialization) of TMPL for the given template ARGS. If there is
978 no such specialization, return NULL_TREE. The ARGS are a vector of
979 arguments, or a vector of vectors of arguments, in the case of
980 templates with more than one level of parameters.
982 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
983 then we search for a partial specialization matching ARGS. This
984 parameter is ignored if TMPL is not a class template. */
986 static tree
988 {
994 /* There should be as many levels of arguments as there are
995 levels of parameters. */
1000 {
1001 tree class_template;
1002 tree class_specialization;
1004 tree fns;
1007 /* The template arguments actually apply to the containing
1008 class. Find the class specialization with those
1009 arguments. */
1011 class_specialization
1015 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1016 for the specialization. */
1020 /* Iterate through the methods with the indicated name, looking
1021 for the one that has an instance of TMPL. */
1024 {
1027 /* using-declarations can add base methods to the method vec,
1028 and we don't want those here. */
1031 }
1033 }
1034 else
1035 {
1037 spec_entry elt;
1038 htab_t specializations;
1046 else
1054 }
1057 }
1059 /* Like retrieve_specialization, but for local declarations. */
1061 static tree
1063 {
1064 tree spec;
1072 }
1074 /* Returns nonzero iff DECL is a specialization of TMPL. */
1076 int
1078 {
1079 tree t;
1082 {
1088 }
1089 else
1090 {
1099 }
1102 }
1104 /* Returns nonzero iff DECL is a specialization of friend declaration
1105 FRIEND_DECL according to [temp.friend]. */
1107 bool
1109 {
1116 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1117 of a template class, we want to check if DECL is a specialization
1118 if this. */
1122 {
1123 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1126 }
1131 /* There is nothing to do if this is not a template friend. */
1138 /* [temp.friend/6]
1139 A member of a class template may be declared to be a friend of a
1140 non-template class. In this case, the corresponding member of
1141 every specialization of the class template is a friend of the
1142 class granting friendship.
1144 For example, given a template friend declaration
1146 template <class T> friend void A<T>::f();
1148 the member function below is considered a friend
1150 template <> struct A<int> {
1151 void f();
1152 };
1154 For this type of template friend, TEMPLATE_DEPTH below will be
1155 nonzero. To determine if DECL is a friend of FRIEND, we first
1156 check if the enclosing class is a specialization of another. */
1163 {
1164 /* Next, we check the members themselves. In order to handle
1165 a few tricky cases, such as when FRIEND_DECL's are
1167 template <class T> friend void A<T>::g(T t);
1168 template <class T> template <T t> friend void A<T>::h();
1170 and DECL's are
1172 void A<int>::g(int);
1173 template <int> void A<int>::h();
1175 we need to figure out ARGS, the template arguments from
1176 the context of DECL. This is required for template substitution
1177 of `T' in the function parameter of `g' and template parameter
1178 of `h' in the above examples. Here ARGS corresponds to `int'. */
1185 {
1187 {
1190 else
1192 current_depth++;
1193 }
1195 }
1198 {
1200 tree friend_type;
1201 tree decl_type;
1202 tree friend_args_type;
1203 tree decl_args_type;
1205 /* Make sure that both DECL and FRIEND_DECL are templates or
1206 non-templates. */
1212 {
1213 /* If both are templates, check template parameter list. */
1214 tree friend_parms
1219 friend_parms))
1223 }
1224 else
1232 /* Check if return types match. */
1236 /* Check if function parameter types match, ignoring the
1237 `this' parameter. */
1246 }
1247 else
1248 {
1249 /* DECL is a TYPE_DECL */
1253 /* Make sure that both DECL and FRIEND_DECL are templates or
1254 non-templates. */
1255 is_template
1262 {
1263 tree friend_parms;
1264 /* If both are templates, check the name of the two
1265 TEMPLATE_DECL's first because is_friend didn't. */
1270 /* Now check template parameter list. */
1271 friend_parms
1274 return comp_template_parms
1276 friend_parms);
1277 }
1278 else
1281 }
1282 }
1284 }
1286 /* Register the specialization SPEC as a specialization of TMPL with
1287 the indicated ARGS. IS_FRIEND indicates whether the specialization
1288 is actually just a friend declaration. Returns SPEC, or an
1289 equivalent prior declaration, if available. */
1291 static tree
1293 hashval_t hash)
1294 {
1295 tree fn;
1297 spec_entry elt;
1303 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1304 register it; we want the corresponding TEMPLATE_DECL instead.
1305 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1306 the more obvious `uses_template_parms (spec)' to avoid problems
1307 with default function arguments. In particular, given
1308 something like this:
1310 template <class T> void f(T t1, T t = T())
1312 the default argument expression is not substituted for in an
1313 instantiation unless and until it is actually needed. */
1317 /* We don't put these specializations in the hash table, but we might
1318 want to give an error about a mismatch. */
1320 else
1321 {
1333 else
1335 }
1337 /* We can sometimes try to re-register a specialization that we've
1338 already got. In particular, regenerate_decl_from_template calls
1339 duplicate_decls which will update the specialization list. But,
1340 we'll still get called again here anyhow. It's more convenient
1341 to simply allow this than to try to prevent it. */
1345 {
1347 {
1350 {
1352 fn);
1354 }
1355 else
1356 {
1357 tree clone;
1358 /* This situation should occur only if the first
1359 specialization is an implicit instantiation, the
1360 second is an explicit specialization, and the
1361 implicit instantiation has not yet been used. That
1362 situation can occur if we have implicitly
1363 instantiated a member function and then specialized
1364 it later.
1366 We can also wind up here if a friend declaration that
1367 looked like an instantiation turns out to be a
1368 specialization:
1370 template <class T> void foo(T);
1371 class S { friend void foo<>(int) };
1372 template <> void foo(int);
1374 We transform the existing DECL in place so that any
1375 pointers to it become pointers to the updated
1376 declaration.
1378 If there was a definition for the template, but not
1379 for the specialization, we want this to look as if
1380 there were no definition, and vice versa. */
1383 /* The call to duplicate_decls will have applied
1384 [temp.expl.spec]:
1386 An explicit specialization of a function template
1387 is inline only if it is explicitly declared to be,
1388 and independently of whether its function template
1389 is.
1391 to the primary function; now copy the inline bits to
1392 the various clones. */
1394 {
1399 }
1403 }
1404 }
1406 {
1408 /* Dup decl failed, but this is a new definition. Set the
1409 line number so any errors match this new
1410 definition. */
1414 }
1415 }
1419 /* A specialization must be declared in the same namespace as the
1420 template it is specializing. */
1426 {
1433 /* TMPL is a forward declaration of a template function; keep a list
1434 of all specializations in case we need to reassign them to a friend
1435 template later in tsubst_friend_function. */
1438 }
1441 }
1443 /* Returns true iff two spec_entry nodes are equivalent. Only compares the
1444 TMPL and ARGS members, ignores SPEC. */
1446 static int
1448 {
1454 }
1456 /* Returns a hash for a template TMPL and template arguments ARGS. */
1458 static hashval_t
1460 {
1463 }
1465 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1466 ignoring SPEC. */
1468 static hashval_t
1470 {
1473 }
1475 /* Recursively calculate a hash value for a template argument ARG, for use
1476 in the hash tables of template specializations. */
1478 hashval_t
1480 {
1492 /* We can get one of these when re-hashing a previous entry in the middle
1493 of substituting into a pack expansion. Just look through it. */
1502 {
1510 {
1515 }
1536 {
1539 {
1542 }
1544 }
1548 {
1551 }
1562 val = iterative_hash_template_arg
1574 val);
1576 val);
1585 /* A lambda can't appear in a template arg, but don't crash on
1586 erroneous input. */
1597 /* Now hash operands as usual. */
1602 }
1605 {
1609 val);
1612 /* Otherwise just compare the types during lookup. */
1621 {
1626 }
1627 }
1630 }
1632 /* Unregister the specialization SPEC as a specialization of TMPL.
1633 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1634 if the SPEC was listed as a specialization of TMPL.
1636 Note that SPEC has been ggc_freed, so we can't look inside it. */
1638 bool
1640 {
1642 spec_entry elt;
1650 {
1655 }
1658 }
1660 /* Compare an entry in the local specializations hash table P1 (which
1661 is really a pointer to a TREE_LIST) with P2 (which is really a
1662 DECL). */
1664 static int
1666 {
1668 }
1670 /* Hash P1, an entry in the local specializations table. */
1672 static hashval_t
1674 {
1676 }
1678 /* Like register_specialization, but for local declarations. We are
1679 registering SPEC, an instantiation of TMPL. */
1681 static void
1683 {
1689 }
1691 /* TYPE is a class type. Returns true if TYPE is an explicitly
1692 specialized class. */
1694 bool
1696 {
1700 }
1702 /* Print the list of functions at FNS, going through all the overloads
1703 for each element of the list. Alternatively, FNS can not be a
1704 TREE_LIST, in which case it will be printed together with all the
1705 overloads.
1707 MORE and *STR should respectively be FALSE and NULL when the function
1708 is called from the outside. They are used internally on recursive
1709 calls. print_candidates manages the two parameters and leaves NULL
1710 in *STR when it ends. */
1712 static void
1714 {
1720 {
1724 }
1725 else
1726 {
1728 {
1729 /* Pick the prefix string. */
1731 {
1734 }
1738 }
1741 }
1744 {
1747 }
1748 }
1750 /* Print the list of candidate FNS in an error message. FNS can also
1751 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1753 void
1755 {
1759 }
1761 /* Returns the template (one of the functions given by TEMPLATE_ID)
1762 which can be specialized to match the indicated DECL with the
1763 explicit template args given in TEMPLATE_ID. The DECL may be
1764 NULL_TREE if none is available. In that case, the functions in
1765 TEMPLATE_ID are non-members.
1767 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1768 specialization of a member template.
1770 The TEMPLATE_COUNT is the number of references to qualifying
1771 template classes that appeared in the name of the function. See
1772 check_explicit_specialization for a more accurate description.
1774 TSK indicates what kind of template declaration (if any) is being
1775 declared. TSK_TEMPLATE indicates that the declaration given by
1776 DECL, though a FUNCTION_DECL, has template parameters, and is
1777 therefore a template function.
1779 The template args (those explicitly specified and those deduced)
1780 are output in a newly created vector *TARGS_OUT.
1782 If it is impossible to determine the result, an error message is
1783 issued. The error_mark_node is returned to indicate failure. */
1785 static tree
1787 tree decl,
1791 tmpl_spec_kind tsk)
1792 {
1793 tree fns;
1794 tree targs;
1795 tree explicit_targs;
1797 /* A TREE_LIST of templates of which DECL may be a specialization.
1798 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1799 corresponding TREE_PURPOSE is the set of template arguments that,
1800 when used to instantiate the template, would produce a function
1801 with the signature of DECL. */
1817 /* Check for baselinks. */
1822 {
1825 }
1827 /* Count the number of template headers specified for this
1828 specialization. */
1836 {
1840 {
1841 tree decl_arg_types;
1842 tree fn_arg_types;
1844 /* In case of explicit specialization, we need to check if
1845 the number of template headers appearing in the specialization
1846 is correct. This is usually done in check_explicit_specialization,
1847 but the check done there cannot be exhaustive when specializing
1848 member functions. Consider the following code:
1850 template <> void A<int>::f(int);
1851 template <> template <> void A<int>::f(int);
1853 Assuming that A<int> is not itself an explicit specialization
1854 already, the first line specializes "f" which is a non-template
1855 member function, whilst the second line specializes "f" which
1856 is a template member function. So both lines are syntactically
1857 correct, and check_explicit_specialization does not reject
1858 them.
1860 Here, we can do better, as we are matching the specialization
1861 against the declarations. We count the number of template
1862 headers, and we check if they match TEMPLATE_COUNT + 1
1863 (TEMPLATE_COUNT is the number of qualifying template classes,
1864 plus there must be another header for the member template
1865 itself).
1867 Notice that if header_count is zero, this is not a
1868 specialization but rather a template instantiation, so there
1869 is no check we can perform here. */
1873 /* Check that the number of template arguments at the
1874 innermost level for DECL is the same as for FN. */
1882 /* DECL might be a specialization of FN. */
1886 /* For a non-static member function, we need to make sure
1887 that the const qualification is the same. Since
1888 get_bindings does not try to merge the "this" parameter,
1889 we must do the comparison explicitly. */
1895 /* Skip the "this" parameter and, for constructors of
1896 classes with virtual bases, the VTT parameter. A
1897 full specialization of a constructor will have a VTT
1898 parameter, but a template never will. */
1899 decl_arg_types
1901 fn_arg_types
1904 /* Check that the number of function parameters matches.
1905 For example,
1906 template <class T> void f(int i = 0);
1907 template <> void f<int>();
1908 The specialization f<int> is invalid but is not caught
1909 by get_bindings below. */
1913 /* Function templates cannot be specializations; there are
1914 no partial specializations of functions. Therefore, if
1915 the type of DECL does not match FN, there is no
1916 match. */
1918 {
1922 }
1924 /* See whether this function might be a specialization of this
1925 template. */
1929 /* We cannot deduce template arguments that when used to
1930 specialize TMPL will produce DECL. */
1933 /* Save this template, and the arguments deduced. */
1935 }
1937 /* FN is an ordinary member function, and we need a
1938 specialization of a member template. */
1939 ;
1941 /* We can get IDENTIFIER_NODEs here in certain erroneous
1942 cases. */
1943 ;
1945 /* This is just an ordinary non-member function. Nothing can
1946 be a specialization of that. */
1947 ;
1949 /* Cannot specialize functions that are created implicitly. */
1950 ;
1951 else
1952 {
1953 tree decl_arg_types;
1955 /* This is an ordinary member function. However, since
1956 we're here, we can assume it's enclosing class is a
1957 template class. For example,
1959 template <typename T> struct S { void f(); };
1960 template <> void S<int>::f() {}
1962 Here, S<int>::f is a non-template, but S<int> is a
1963 template class. If FN has the same type as DECL, we
1964 might be in business. */
1967 /* Its enclosing class is an explicit specialization
1968 of a template class. This is not a candidate. */
1973 /* The return types differ. */
1976 /* Adjust the type of DECL in case FN is a static member. */
1983 decl_arg_types))
1984 /* They match! */
1986 }
1987 }
1990 {
1991 /* We have:
1993 [temp.expl.spec]
1995 It is possible for a specialization with a given function
1996 signature to be instantiated from more than one function
1997 template. In such cases, explicit specification of the
1998 template arguments must be used to uniquely identify the
1999 function template specialization being specialized.
2001 Note that here, there's no suggestion that we're supposed to
2002 determine which of the candidate templates is most
2003 specialized. However, we, also have:
2005 [temp.func.order]
2007 Partial ordering of overloaded function template
2008 declarations is used in the following contexts to select
2009 the function template to which a function template
2010 specialization refers:
2012 -- when an explicit specialization refers to a function
2013 template.
2015 So, we do use the partial ordering rules, at least for now.
2016 This extension can only serve to make invalid programs valid,
2017 so it's safe. And, there is strong anecdotal evidence that
2018 the committee intended the partial ordering rules to apply;
2019 the EDG front end has that behavior, and John Spicer claims
2020 that the committee simply forgot to delete the wording in
2021 [temp.expl.spec]. */
2024 {
2027 }
2028 }
2031 {
2039 }
2043 {
2049 }
2051 /* We have one, and exactly one, match. */
2053 {
2056 /* DECL is a re-declaration or partial instantiation of a template
2057 function. */
2060 /* It was a specialization of an ordinary member function in a
2061 template class. */
2063 }
2065 /* It was a specialization of a template. */
2068 {
2073 }
2074 else
2077 }
2079 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2080 but with the default argument values filled in from those in the
2081 TMPL_TYPES. */
2083 static tree
2085 tree tmpl_types)
2086 {
2087 tree new_spec_types;
2095 /* Substitute into the rest of the list. */
2096 new_spec_types =
2100 /* Add the default argument for this parameter. */
2103 new_spec_types);
2104 }
2106 /* DECL is an explicit specialization. Replicate default arguments
2107 from the template it specializes. (That way, code like:
2109 template <class T> void f(T = 3);
2110 template <> void f(double);
2111 void g () { f (); }
2113 works, as required.) An alternative approach would be to look up
2114 the correct default arguments at the call-site, but this approach
2115 is consistent with how implicit instantiations are handled. */
2117 static void
2119 {
2120 tree tmpl;
2121 tree spec_types;
2122 tree tmpl_types;
2123 tree new_spec_types;
2124 tree old_type;
2125 tree new_type;
2126 tree t;
2131 /* See if there's anything we need to do. */
2144 {
2145 /* Remove the this pointer, but remember the object's type for
2146 CV quals. */
2152 {
2153 /* DECL may contain more parameters than TMPL due to the extra
2154 in-charge parameter in constructors and destructors. */
2157 }
2159 {
2162 }
2163 }
2165 /* Compute the merged default arguments. */
2166 new_spec_types =
2169 /* Compute the new FUNCTION_TYPE. */
2171 {
2175 new_spec_types);
2178 /* Put the in-charge parameter back. */
2181 new_spec_types);
2185 new_spec_types);
2186 }
2187 else
2189 new_spec_types);
2195 }
2197 /* Check to see if the function just declared, as indicated in
2198 DECLARATOR, and in DECL, is a specialization of a function
2199 template. We may also discover that the declaration is an explicit
2200 instantiation at this point.
2202 Returns DECL, or an equivalent declaration that should be used
2203 instead if all goes well. Issues an error message if something is
2204 amiss. Returns error_mark_node if the error is not easily
2205 recoverable.
2207 FLAGS is a bitmask consisting of the following flags:
2209 2: The function has a definition.
2210 4: The function is a friend.
2212 The TEMPLATE_COUNT is the number of references to qualifying
2213 template classes that appeared in the name of the function. For
2214 example, in
2216 template <class T> struct S { void f(); };
2217 void S<int>::f();
2219 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2220 classes are not counted in the TEMPLATE_COUNT, so that in
2222 template <class T> struct S {};
2223 template <> struct S<int> { void f(); }
2224 template <> void S<int>::f();
2226 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2227 invalid; there should be no template <>.)
2229 If the function is a specialization, it is marked as such via
2230 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2231 is set up correctly, and it is added to the list of specializations
2232 for that template. */
2234 tree
2236 tree decl,
2239 {
2247 tmpl_spec_kind tsk;
2250 {
2253 else
2255 }
2256 else
2260 {
2263 {
2266 }
2268 {
2270 /* This could be something like:
2272 template <class T> void f(T);
2273 class S { friend void f<>(int); } */
2275 else
2276 {
2277 /* This case handles bogus declarations like template <>
2278 template <class T> void f<int>(); */
2281 declarator);
2283 }
2284 }
2288 /* The error has already been reported in
2289 check_specialization_scope. */
2295 /* Fall through. */
2308 decl);
2311 else
2315 /* Fall through. */
2320 else
2326 {
2327 /* This case handles bogus declarations like template <>
2328 template <class T> void f<int>(); */
2333 else
2335 declarator);
2337 }
2340 /* This is a specialization of a member template, without
2341 specialization the containing class. Something like:
2343 template <class T> struct S {
2344 template <class U> void f (U);
2345 };
2346 template <> template <class U> void S<int>::f(U) {}
2348 That's a specialization -- but of the entire template. */
2354 }
2357 {
2361 {
2365 }
2366 }
2369 {
2373 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2375 {
2376 tree fns;
2381 else
2382 {
2383 /* If there is no class context, the explicit instantiation
2384 must be at namespace scope. */
2387 /* Find the namespace binding, using the declaration
2388 context. */
2392 {
2395 }
2396 else
2397 {
2403 }
2404 }
2407 }
2413 {
2415 /* A specialization in class scope. This is invalid,
2416 but the error will already have been flagged by
2417 check_specialization_scope. */
2419 else
2420 {
2421 /* It's not valid to write an explicit instantiation in
2422 class scope, e.g.:
2424 class C { template void f(); }
2426 This case is caught by the parser. However, on
2427 something like:
2429 template class C { void f(); };
2431 (which is invalid) we can get here. The error will be
2432 issued later. */
2433 ;
2434 }
2437 }
2440 IDENTIFIER_NODE))
2441 {
2442 /* Find the list of functions in ctype that have the same
2443 name as the declared function. */
2449 {
2454 {
2455 /* From [temp.expl.spec]:
2457 If such an explicit specialization for the member
2458 of a class template names an implicitly-declared
2459 special member function (clause _special_), the
2460 program is ill-formed.
2462 Similar language is found in [temp.explicit]. */
2465 }
2468 }
2471 {
2475 }
2476 else
2477 {
2479 tree ovl;
2481 /* For a type-conversion operator, we cannot do a
2482 name-based lookup. We might be looking for `operator
2483 int' which will be a specialization of `operator T'.
2484 So, we find *all* the conversion operators, and then
2485 select from them. */
2493 {
2495 /* There are no more conversion functions. */
2498 /* Glue all these conversion functions together
2499 with those we already have. */
2502 }
2503 }
2506 {
2509 }
2510 else
2512 }
2514 /* Figure out what exactly is being specialized at this point.
2515 Note that for an explicit instantiation, even one for a
2516 member function, we cannot tell apriori whether the
2517 instantiation is for a member template, or just a member
2518 function of a template class. Even if a member template is
2519 being instantiated, the member template arguments may be
2520 elided if they can be deduced from the rest of the
2521 declaration. */
2524 member_specialization,
2525 template_count,
2526 tsk);
2529 /* We couldn't figure out what this declaration was
2530 specializing. */
2532 else
2533 {
2537 {
2538 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2539 is done by do_decl_instantiation later. */
2545 {
2546 /* If TMPL is not the most general template (for
2547 example, if TMPL is a friend template that is
2548 injected into namespace scope), then there will
2549 be too many levels of TARGS. Remove some of them
2550 here. */
2552 tree new_targs;
2559 }
2562 }
2564 /* If we thought that the DECL was a member function, but it
2565 turns out to be specializing a static member function,
2566 make DECL a static member function as well. */
2571 /* If this is a specialization of a member template of a
2572 template class, we want to return the TEMPLATE_DECL, not
2573 the specialization of it. */
2575 {
2580 {
2581 tree parm;
2585 /* We want to use the argument list specified in the
2586 definition, not in the original declaration. */
2591 }
2594 }
2596 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2599 /* Inherit default function arguments from the template
2600 DECL is specializing. */
2603 /* This specialization has the same protection as the
2604 template it specializes. */
2608 /* 7.1.1-1 [dcl.stc]
2610 A storage-class-specifier shall not be specified in an
2611 explicit specialization...
2613 The parser rejects these, so unless action is taken here,
2614 explicit function specializations will always appear with
2615 global linkage.
2617 The action recommended by the C++ CWG in response to C++
2618 defect report 605 is to make the storage class and linkage
2619 of the explicit specialization match the templated function:
2621 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2622 */
2624 {
2628 /* This specialization has the same linkage and visibility as
2629 the function template it specializes. */
2632 {
2635 }
2638 {
2641 }
2642 }
2644 /* If DECL is a friend declaration, declared using an
2645 unqualified name, the namespace associated with DECL may
2646 have been set incorrectly. For example, in:
2648 template <typename T> void f(T);
2649 namespace N {
2650 struct S { friend void f<int>(int); }
2651 }
2653 we will have set the DECL_CONTEXT for the friend
2654 declaration to N, rather than to the global namespace. */
2659 /* This is not really a declaration of a specialization.
2660 It's just the name of an instantiation. But, it's not
2661 a request for an instantiation, either. */
2664 /* This is indeed a specialization. In case of constructors
2665 and destructors, we need in-charge and not-in-charge
2666 versions in V3 ABI. */
2669 /* Register this specialization so that we can find it
2670 again. */
2672 }
2673 }
2676 }
2678 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2679 parameters. These are represented in the same format used for
2680 DECL_TEMPLATE_PARMS. */
2682 int
2684 {
2685 const_tree p1;
2686 const_tree p2;
2694 {
2706 {
2710 /* If either of the template parameters are invalid, assume
2711 they match for the sake of error recovery. */
2724 }
2725 }
2728 /* One set of parameters has more parameters lists than the
2729 other. */
2733 }
2735 /* Determine whether PARM is a parameter pack. */
2737 bool
2739 {
2740 /* Determine if we have a non-type template parameter pack. */
2745 /* If this is a list of template parameters, we could get a
2746 TYPE_DECL or a TEMPLATE_DECL. */
2753 }
2755 /* Determine if T is a function parameter pack. */
2757 bool
2759 {
2763 }
2765 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
2766 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
2768 tree
2770 {
2777 }
2779 /* Return true iff the function parameter PARAM_DECL was expanded
2780 from the function parameter pack PACK. */
2782 bool
2784 {
2789 /* The parameter pack and its pack arguments have the same
2790 DECL_PARM_INDEX. */
2792 }
2794 /* Determine whether ARGS describes a variadic template args list,
2795 i.e., one that is terminated by a template argument pack. */
2797 static bool
2799 {
2801 tree last_parm;
2815 }
2817 /* Generate a new name for the parameter pack name NAME (an
2818 IDENTIFIER_NODE) that incorporates its */
2820 static tree
2822 {
2823 /* Munge the name to include the parameter index. */
2824 #define NUMBUF_LEN 128
2836 }
2838 /* Return true if T is a primary function
2839 or class template instantiation. */
2841 bool
2843 {
2855 }
2857 /* Return true if PARM is a template template parameter. */
2859 bool
2861 {
2863 }
2865 /* Return the template parameters of T if T is a
2866 primary template instantiation, NULL otherwise. */
2868 tree
2870 {
2875 parms = INNERMOST_TEMPLATE_PARMS
2879 }
2881 /* Return the template parameters of the LEVELth level from the full list
2882 of template parameters PARMS. */
2884 tree
2886 {
2887 tree p;
2898 }
2900 /* Returns the template arguments of T if T is a template instantiation,
2901 NULL otherwise. */
2903 tree
2905 {
2913 }
2915 /* Return the argument pack elements of T if T is a template argument pack,
2916 NULL otherwise. */
2918 tree
2920 {
2926 }
2928 /* Structure used to track the progress of find_parameter_packs_r. */
2929 struct find_parameter_pack_data
2930 {
2931 /* TREE_LIST that will contain all of the parameter packs found by
2932 the traversal. */
2935 /* Set of AST nodes that have been visited by the traversal. */
2937 };
2939 /* Identifies all of the argument packs that occur in a template
2940 argument and appends them to the TREE_LIST inside DATA, which is a
2941 find_parameter_pack_data structure. This is a subroutine of
2942 make_pack_expansion and uses_parameter_packs. */
2943 static tree
2945 {
2951 /* Identify whether this is a parameter pack or not. */
2953 {
2967 {
2968 /* We don't want to walk into the type of a PARM_DECL,
2969 because we don't want to see the type parameter pack. */
2972 }
2976 /* Not a parameter pack. */
2978 }
2981 {
2982 /* Add this parameter pack to the list. */
2984 }
2990 /* This switch statement will return immediately if we don't find a
2991 parameter pack. */
2993 {
2998 /* Check the template itself. */
3001 /* Check the template arguments. */
3017 /* Fall through. */
3059 }
3062 }
3064 /* Determines if the expression or type T uses any parameter packs. */
3065 bool
3067 {
3075 }
3077 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3078 representation a base-class initializer into a parameter pack
3079 expansion. If all goes well, the resulting node will be an
3080 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3081 respectively. */
3082 tree
3084 {
3085 tree result;
3094 {
3095 /* The only time we will see a TREE_LIST here is for a base
3096 class initializer. In this case, the TREE_PURPOSE will be a
3097 _TYPE node (representing the base class expansion we're
3098 initializing) and the TREE_VALUE will be a TREE_LIST
3099 containing the initialization arguments.
3101 The resulting expansion looks somewhat different from most
3102 expansions. Rather than returning just one _EXPANSION, we
3103 return a TREE_LIST whose TREE_PURPOSE is a
3104 TYPE_PACK_EXPANSION containing the bases that will be
3105 initialized. The TREE_VALUE will be identical to the
3106 original TREE_VALUE, which is a list of arguments that will
3107 be passed to each base. We do not introduce any new pack
3108 expansion nodes into the TREE_VALUE (although it is possible
3109 that some already exist), because the TREE_PURPOSE and
3110 TREE_VALUE all need to be expanded together with the same
3111 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3112 resulting TREE_PURPOSE will mention the parameter packs in
3113 both the bases and the arguments to the bases. */
3114 tree purpose;
3115 tree value;
3118 /* Determine which parameter packs will be used by the base
3119 class expansion. */
3126 {
3130 }
3133 {
3134 /* Collect the sets of parameter packs used in each of the
3135 initialization arguments. */
3137 {
3138 /* Determine which parameter packs will be expanded in this
3139 argument. */
3142 }
3143 }
3147 /* Create the pack expansion type for the base type. */
3152 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3153 they will rarely be compared to anything. */
3157 }
3162 /* Build the PACK_EXPANSION_* node. */
3163 result = for_types
3168 {
3169 /* Propagate type and const-expression information. */
3172 }
3173 else
3174 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3175 they will rarely be compared to anything. */
3178 /* Determine which parameter packs will be expanded. */
3184 /* Make sure we found some parameter packs. */
3186 {
3189 else
3192 }
3196 }
3198 /* Checks T for any "bare" parameter packs, which have not yet been
3199 expanded, and issues an error if any are found. This operation can
3200 only be done on full expressions or types (e.g., an expression
3201 statement, "if" condition, etc.), because we could have expressions like:
3203 foo(f(g(h(args)))...)
3205 where "args" is a parameter pack. check_for_bare_parameter_packs
3206 should not be called for the subexpressions args, h(args),
3207 g(h(args)), or f(g(h(args))), because we would produce erroneous
3208 error messages.
3210 Returns TRUE and emits an error if there were bare parameter packs,
3211 returns FALSE otherwise. */
3212 bool
3214 {
3230 {
3233 {
3242 else
3247 else
3251 }
3254 }
3257 }
3259 /* Expand any parameter packs that occur in the template arguments in
3260 ARGS. */
3261 tree
3263 {
3269 /* First, determine if we need to expand anything, and the number of
3270 slots we'll need. */
3272 {
3277 {
3281 else
3283 }
3284 else
3285 {
3287 num_result_args++;
3288 }
3289 }
3291 /* If no expansion is necessary, we're done. */
3295 /* Expand arguments. */
3298 non_default_args_count =
3301 {
3304 {
3311 }
3312 else
3313 {
3316 }
3317 }
3321 }
3323 /* Checks if DECL shadows a template parameter.
3325 [temp.local]: A template-parameter shall not be redeclared within its
3326 scope (including nested scopes).
3328 Emits an error and returns TRUE if the DECL shadows a parameter,
3329 returns FALSE otherwise. */
3331 bool
3333 {
3334 tree olddecl;
3336 /* If we're not in a template, we can't possibly shadow a template
3337 parameter. */
3341 /* Figure out what we're shadowing. */
3346 /* If there's no previous binding for this name, we're not shadowing
3347 anything, let alone a template parameter. */
3351 /* If we're not shadowing a template parameter, we're done. Note
3352 that OLDDECL might be an OVERLOAD (or perhaps even an
3353 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3354 node. */
3358 /* We check for decl != olddecl to avoid bogus errors for using a
3359 name inside a class. We check TPFI to avoid duplicate errors for
3360 inline member templates. */
3368 }
3370 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3371 ORIG_LEVEL, DECL, and TYPE. NUM_SIBLINGS is the total number of
3372 template parameters. */
3374 static tree
3379 tree decl,
3380 tree type)
3381 {
3393 }
3395 /* Find the canonical type parameter for the given template type
3396 parameter. Returns the canonical type parameter, which may be TYPE
3397 if no such parameter existed. */
3399 static tree
3401 {
3402 tree list;
3416 else
3417 {
3422 }
3423 }
3425 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3426 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3427 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3428 new one is created. */
3430 static tree
3432 tsubst_flags_t complain)
3433 {
3438 {
3458 /* Template template parameters need this. */
3463 }
3466 }
3468 /* Process information from new template parameter PARM and append it
3469 to the LIST being built. This new parameter is a non-type
3470 parameter iff IS_NON_TYPE is true. This new parameter is a
3471 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3472 is in PARM_LOC. NUM_TEMPLATE_PARMS is the size of the template
3473 parameter list PARM belongs to. This is used used to create a
3474 proper canonical type for the type of PARM that is to be created,
3475 iff PARM is a type. If the size is not known, this parameter shall
3476 be set to 0. */
3478 tree
3482 {
3484 tree defval;
3485 tree err_parm_list;
3492 {
3496 {
3500 else
3502 }
3505 }
3506 else
3510 {
3516 {
3520 }
3521 else
3522 {
3523 /* [temp.param]
3525 The top-level cv-qualifiers on the template-parameter are
3526 ignored when determining its type. */
3529 {
3533 }
3536 {
3537 /* This template parameter is not a parameter pack, but it
3538 should be. Complain about "bare" parameter packs. */
3541 /* Recover by calling this a parameter pack. */
3543 }
3544 }
3546 /* A template parameter is not modifiable. */
3555 processing_template_decl,
3556 num_template_parms,
3561 }
3562 else
3563 {
3564 tree t;
3568 {
3570 /* This is for distinguishing between real templates and template
3571 template parameters */
3575 }
3576 else
3577 {
3579 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3582 }
3589 processing_template_decl,
3590 num_template_parms,
3594 }
3600 }
3602 /* The end of a template parameter list has been reached. Process the
3603 tree list into a parameter vector, converting each parameter into a more
3604 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3605 as PARM_DECLs. */
3607 tree
3609 {
3614 current_template_parms
3619 {
3623 }
3628 }
3630 /* Create a new type almost identical to TYPE but which has the
3631 following differences:
3633 1/ T has a new TEMPLATE_PARM_INDEX that carries the new number of
3634 template sibling parameters of T.
3636 2/ T has a new canonical type that matches the new number
3637 of sibling parms.
3639 3/ From now on, T is going to be what lookups referring to the
3640 name of TYPE will return. No lookup should return TYPE anymore.
3642 NUM_PARMS is the new number of sibling parms TYPE belongs to.
3644 This is a subroutine of fixup_template_parms. */
3646 static tree
3648 {
3650 tree t;
3651 /* This is the decl which name is inserted into the symbol table for
3652 the template parm type. So whenever we lookup the type name, this
3653 is the DECL we get. */
3654 tree decl;
3656 /* Do not fix up the type twice. */
3671 num_parms,
3682 /* Update the type associated to the type name stored in the symbol
3683 table. Now, whenever the type name is looked up, the resulting
3684 type is properly fixed up. */
3690 }
3692 /* Create and return a new TEMPLATE_PARM_INDEX that is almost
3693 identical to I, but that is fixed up as to:
3695 1/ carry the number of sibling parms (NUM_PARMS) of the template
3696 parm represented by I.
3698 2/ replace all references to template parm types declared before I
3699 (in the same template parm list as I) by references to template
3700 parm types contained in ARGS. ARGS should contain the list of
3701 template parms that have been fixed up so far, in a form suitable
3702 to be passed to tsubst.
3704 This is a subroutine of fixup_template_parms. */
3706 static tree
3708 {
3713 /* Do not fix up the index twice. */
3723 num_parms,
3735 }
3737 /*
3738 This is a subroutine of fixup_template_parms.
3740 It computes the canonical type of the type of the template
3741 parameter PARM_DESC and update all references to that type so that
3742 they use the newly computed canonical type. No access check is
3743 performed during the fixup. PARM_DESC is a TREE_LIST which
3744 TREE_VALUE is the template parameter and its TREE_PURPOSE is the
3745 default argument of the template parm if any. IDX is the index of
3746 the template parameter, starting at 0. NUM_PARMS is the number of
3747 template parameters in the set PARM_DESC belongs to. ARGLIST is a
3748 TREE_VEC containing the full set of template parameters in a form
3749 suitable to be passed to substs functions as their ARGS
3750 argument. This is what current_template_args returns for a given
3751 template. The innermost vector of args in ARGLIST is the set of
3752 template parms that have been fixed up so far. This function adds
3753 the fixed up parameter into that vector. */
3755 static void
3759 tree arglist)
3760 {
3767 {
3768 /* PARM is a template type parameter. Fix up its type, add
3769 the fixed-up template parm to the vector of fixed-up
3770 template parms so far, and substitute the fixed-up
3771 template parms into the default argument of this
3772 parameter. */
3773 tree t =
3778 }
3780 {
3781 /* PARM is a template template parameter. This is going to
3782 be interesting. */
3786 /* First, fix up the parms of the template template parm
3787 because the parms are involved in defining the new canonical
3788 type of the template template parm. */
3790 /* So we need to substitute the template parm types that have
3791 been fixed up so far into the template parms of this template
3792 template parm. E.g, consider this:
3794 template<class T, template<T u> class TT> class S;
3796 In this case we want to substitute T into the
3797 template parameters of TT.
3799 So let's walk the template parms of PARM here, and
3800 tsubst ARGLIST into into each of the template
3801 parms. */
3803 /* For this substitution we need to build the full set of
3804 template parameters and use that as arguments for the
3805 tsubsting function. */
3808 /* This will contain the innermost parms of PARM into which
3809 we have substituted so far. */
3813 {
3814 tree parameter;
3818 /* INNERMOST_ARGS needs to have at least the same number
3819 of elements as the index PARAMETER, ortherwise
3820 tsubsting into PARAMETER will result in partially
3821 instantiating it, reducing its tempate parm
3822 level. Let's tactically fill INNERMOST_ARGS for that
3823 purpose. */
3829 targs);
3830 }
3832 /* Now fix up the type of the template template parm. */
3839 }
3841 {
3842 /* PARM is a non-type template parameter. We need to:
3844 * Fix up its TEMPLATE_PARM_INDEX to make it carry the
3845 proper number of sibling parameters.
3847 * Make lookups of the template parameter return a reference
3848 to the fixed-up index. No lookup should return references
3849 to the former index anymore.
3851 * Substitute the template parms that got fixed up so far
3853 * into the type of PARM. */
3857 /* PUSHED_DECL is the decl added to the symbol table with
3858 the name of the parameter. E,g:
3860 template<class T, T u> //#0
3861 auto my_function(T t) -> decltype(u); //#1
3863 Here, when looking up u at //#1, we get the decl of u
3864 resulting from the declaration in #0. This is what
3865 PUSHED_DECL is. We need to replace the reference to the
3866 old TEMPLATE_PARM_INDEX carried by PUSHED_DECL by the
3867 fixed-up TEMPLATE_PARM_INDEX. */
3870 /* Let's fix up the TEMPLATE_PARM_INDEX then. Note that we must
3871 fixup the type of PUSHED_DECL as well and luckily
3872 fixup_template_parm_index does it for us too. */
3873 tree fixed_up_index =
3878 /* Add this fixed up PARM to the template parms we've fixed
3879 up so far and use that to substitute the fixed-up
3880 template parms into the type of PARM. */
3885 }
3892 }
3894 /* Walk the current template parms and properly compute the canonical
3895 types of the dependent types created during
3896 cp_parser_template_parameter_list. */
3898 void
3900 {
3901 tree arglist;
3902 tree parameter_vec;
3903 tree fixedup_args;
3912 /* This vector contains the current innermost template parms that
3913 have been fixed up so far. The form of FIXEDUP_ARGS is suitable
3914 to be passed to tsubst* functions as their ARGS argument. */
3917 /* This vector contains the full set of template parms in a form
3918 suitable to be passed to substs functions as their ARGS
3919 argument. */
3923 /* Let's do the proper fixup now. */
3927 }
3929 /* end_template_decl is called after a template declaration is seen. */
3931 void
3933 {
3939 /* This matches the pushlevel in begin_template_parm_list. */
3944 }
3946 /* Takes a TREE_LIST representing a template parameter and convert it
3947 into an argument suitable to be passed to the type substitution
3948 functions. Note that If the TREE_LIST contains an error_mark
3949 node, the returned argument is error_mark_node. */
3951 static tree
3953 {
3966 {
3970 {
3971 /* Turn this argument into a TYPE_ARGUMENT_PACK
3972 with a single element, which expands T. */
3974 #ifdef ENABLE_CHECKING
3975 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3977 #endif
3982 }
3983 }
3984 else
3985 {
3989 {
3990 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3991 with a single element, which expands T. */
3994 #ifdef ENABLE_CHECKING
3995 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3997 #endif
4003 }
4004 }
4006 }
4008 /* Within the declaration of a template, return all levels of template
4009 parameters that apply. The template parameters are represented as
4010 a TREE_VEC, in the form documented in cp-tree.h for template
4011 arguments. */
4013 static tree
4015 {
4016 tree header;
4021 /* If there is only one level of template parameters, we do not
4022 create a TREE_VEC of TREE_VECs. Instead, we return a single
4023 TREE_VEC containing the arguments. */
4028 {
4036 #ifdef ENABLE_CHECKING
4038 #endif
4042 else
4044 }
4047 /* This can happen for template parms of a template template
4048 parameter, e.g:
4050 template<template<class T, class U> class TT> struct S;
4052 Consider the level of the parms of TT; T and U both have
4053 level 2; TT has no template parm of level 1. So in this case
4054 the first element of full_template_args is NULL_TREE. If we
4055 leave it like this TMPL_ARG_DEPTH on args returns 1 instead
4056 of 2. This will make tsubst wrongly consider that T and U
4057 have level 1. Instead, let's create a dummy vector as the
4058 first element of full_template_args so that TMPL_ARG_DEPTH
4059 returns the correct depth for args. */
4062 }
4064 /* Update the declared TYPE by doing any lookups which were thought to be
4065 dependent, but are not now that we know the SCOPE of the declarator. */
4067 tree
4069 {
4080 /* Don't bother building up the args in this case. */
4082 {
4083 /* tsubst in the args corresponding to the template parameters,
4084 including auto if present. Most things will be unchanged, but
4085 make_typename_type and tsubst_qualified_id will resolve
4086 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4089 tree pushed;
4091 {
4095 }
4100 }
4106 {
4109 else
4111 }
4113 }
4115 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4116 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
4117 a member template. Used by push_template_decl below. */
4119 static tree
4121 {
4129 }
4131 struct template_parm_data
4132 {
4133 /* The level of the template parameters we are currently
4134 processing. */
4137 /* The index of the specialization argument we are currently
4138 processing. */
4141 /* An array whose size is the number of template parameters. The
4142 elements are nonzero if the parameter has been used in any one
4143 of the arguments processed so far. */
4146 /* An array whose size is the number of template arguments. The
4147 elements are nonzero if the argument makes use of template
4148 parameters of this level. */
4150 };
4152 /* Subroutine of push_template_decl used to see if each template
4153 parameter in a partial specialization is used in the explicit
4154 argument list. If T is of the LEVEL given in DATA (which is
4155 treated as a template_parm_data*), then DATA->PARMS is marked
4156 appropriately. */
4158 static int
4160 {
4166 {
4169 }
4170 else
4171 {
4174 }
4177 {
4180 }
4182 /* Return zero so that for_each_template_parm will continue the
4183 traversal of the tree; we want to mark *every* template parm. */
4185 }
4187 /* Process the partial specialization DECL. */
4189 static tree
4191 {
4197 tree inner_parms;
4198 tree inst;
4211 /* We check that each of the template parameters given in the
4212 partial specialization is used in the argument list to the
4213 specialization. For example:
4215 template <class T> struct S;
4216 template <class T> struct S<T*>;
4218 The second declaration is OK because `T*' uses the template
4219 parameter T, whereas
4221 template <class T> struct S<int>;
4223 is no good. Even trickier is:
4225 template <class T>
4226 struct S1
4227 {
4228 template <class U>
4229 struct S2;
4230 template <class U>
4231 struct S2<T>;
4232 };
4234 The S2<T> declaration is actually invalid; it is a
4235 full-specialization. Of course,
4237 template <class U>
4238 struct S2<T (*)(U)>;
4240 or some such would have been OK. */
4248 {
4253 NULL,
4255 }
4258 {
4259 /* One of the template parms was not used in the
4260 specialization. */
4262 {
4265 }
4268 }
4273 /* [temp.class.spec]
4275 The argument list of the specialization shall not be identical to
4276 the implicit argument list of the primary template. */
4283 /* [temp.class.spec]
4285 A partially specialized non-type argument expression shall not
4286 involve template parameters of the partial specialization except
4287 when the argument expression is a simple identifier.
4289 The type of a template parameter corresponding to a specialized
4290 non-type argument shall not be dependent on a parameter of the
4291 specialization.
4293 Also, we verify that pack expansions only occur at the
4294 end of the argument list. */
4298 {
4305 {
4306 /* Extract the arguments from the argument pack. We'll be
4307 iterating over these in the following loop. */
4310 }
4313 {
4315 /* Get the Jth argument in the parameter pack. */
4319 {
4320 /* Pack expansions must come at the end of the
4321 argument list. */
4324 {
4328 else
4331 }
4332 }
4335 /* We only care about the pattern. */
4341 /* This next line is the `argument expression is not just a
4342 simple identifier' condition and also the `specialized
4343 non-type argument' bit. */
4345 {
4349 arg);
4350 else
4351 {
4352 /* Look at the corresponding template parameter,
4353 marking which template parameters its type depends
4354 upon. */
4358 {
4359 /* We haven't yet initialized TPD2. Do so now. */
4361 /* The number of parameters here is the number in the
4362 main template, which, as checked in the assertion
4363 above, is NARGS. */
4367 }
4369 /* Mark the template parameters. But this time, we're
4370 looking for the template parameters of the main
4371 template, not in the specialization. */
4378 NULL,
4382 {
4383 /* The type depended on some template parameters.
4384 If they are fully specialized in the
4385 specialization, that's OK. */
4394 "type %qT of template argument %qE depends "
4396 "type %qT of template argument %qE depends "
4398 type,
4399 arg);
4400 }
4401 }
4402 }
4403 }
4404 }
4406 /* We should only get here once. */
4416 {
4420 {
4424 "partial specialization of %qT after instantiation "
4426 }
4427 }
4430 }
4432 /* Check that a template declaration's use of default arguments and
4433 parameter packs is not invalid. Here, PARMS are the template
4434 parameters. IS_PRIMARY is nonzero if DECL is the thing declared by
4435 a primary template. IS_PARTIAL is nonzero if DECL is a partial
4436 specialization.
4439 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4440 declaration (but not a definition); 1 indicates a declaration, 2
4441 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4442 emitted for extraneous default arguments.
4444 Returns TRUE if there were no errors found, FALSE otherwise. */
4446 bool
4449 {
4452 tree parm_level;
4455 /* [temp.param]
4457 A default template-argument shall not be specified in a
4458 function template declaration or a function template definition, nor
4459 in the template-parameter-list of the definition of a member of a
4460 class template. */
4463 /* You can't have a function template declaration in a local
4464 scope, nor you can you define a member of a class template in a
4465 local scope. */
4472 /* If this is either a friend defined in the scope of the class
4473 or a member function. */
4479 /* And, if it was a member function, it really was defined in
4480 the scope of the class. */
4483 /* We already checked these parameters when the template was
4484 declared, so there's no need to do it again now. This function
4485 was defined in class scope, but we're processing it's body now
4486 that the class is complete. */
4489 /* Core issue 226 (C++0x only): the following only applies to class
4490 templates. */
4492 {
4493 /* [temp.param]
4495 If a template-parameter has a default template-argument, all
4496 subsequent template-parameters shall have a default
4497 template-argument supplied. */
4499 {
4506 {
4516 {
4518 /* For better subsequent error-recovery, we indicate that
4519 there should have been a default argument. */
4522 }
4524 && !is_partial
4525 && !is_friend_decl
4526 /* Don't complain about an enclosing partial
4527 specialization. */
4532 {
4533 /* A primary class template can only have one
4534 parameter pack, at the end of the template
4535 parameter list. */
4540 else
4548 }
4549 }
4550 }
4551 }
4554 || is_partial
4555 || !is_primary
4557 /* For an ordinary class template, default template arguments are
4558 allowed at the innermost level, e.g.:
4559 template <class T = int>
4560 struct S {};
4561 but, in a partial specialization, they're not allowed even
4562 there, as we have in [temp.class.spec]:
4564 The template parameter list of a specialization shall not
4565 contain default template argument values.
4567 So, for a partial specialization, or for a function template
4568 (in C++98/C++03), we look at all of them. */
4569 ;
4570 else
4571 /* But, for a primary class template that is not a partial
4572 specialization we look at all template parameters except the
4573 innermost ones. */
4576 /* Figure out what error message to issue. */
4589 else
4593 /* If we're inside a class definition, there's no need to
4594 examine the parameters to the class itself. On the one
4595 hand, they will be checked when the class is defined, and,
4596 on the other, default arguments are valid in things like:
4597 template <class T = double>
4598 struct S { template <class U> void f(U); };
4599 Here the default argument for `S' has no bearing on the
4600 declaration of `f'. */
4602 else
4603 /* Check everything. */
4609 {
4616 {
4621 {
4623 {
4630 }
4632 /* Clear out the default argument so that we are not
4633 confused later. */
4635 }
4636 }
4638 /* At this point, if we're still interested in issuing messages,
4639 they must apply to classes surrounding the object declared. */
4643 }
4646 }
4648 /* Worker for push_template_decl_real, called via
4649 for_each_template_parm. DATA is really an int, indicating the
4650 level of the parameters we are interested in. If T is a template
4651 parameter of that level, return nonzero. */
4653 static int
4655 {
4661 else
4664 }
4666 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
4667 parameters given by current_template_args, or reuses a
4668 previously existing one, if appropriate. Returns the DECL, or an
4669 equivalent one, if it is replaced via a call to duplicate_decls.
4671 If IS_FRIEND is true, DECL is a friend declaration. */
4673 tree
4675 {
4676 tree tmpl;
4677 tree args;
4678 tree info;
4679 tree ctx;
4683 /* True if the template is a member template, in the sense of
4684 [temp.mem]. */
4690 /* See if this is a partial specialization. */
4699 /* For a friend, we want the context of the friend function, not
4700 the type of which it is a friend. */
4704 /* In the case of a virtual function, we want the class in which
4705 it is defined. */
4707 else
4708 /* Otherwise, if we're currently defining some class, the DECL
4709 is assumed to be a member of the class. */
4718 /* See if this is a primary template. */
4720 /* A friend template that specifies a class context, i.e.
4721 template <typename T> friend void A<T>::f();
4722 is not primary. */
4724 else
4728 {
4733 {
4736 }
4738 {
4740 {
4741 /* [temp.mem]
4743 A destructor shall not be a member template. */
4746 }
4753 {
4754 /* [basic.stc.dynamic.allocation]
4756 An allocation function can be a function
4757 template. ... Template allocation functions shall
4758 have two or more parameters. */
4761 }
4762 }
4766 else
4767 {
4770 }
4771 }
4773 /* Check to see that the rules regarding the use of default
4774 arguments are not being violated. */
4778 /* Ensure that there are no parameter packs in the type of this
4779 declaration that have not been expanded. */
4781 {
4782 /* Check each of the arguments individually to see if there are
4783 any bare parameter packs. */
4789 {
4792 {
4793 /* This is a PARM_DECL that contains unexpanded parameter
4794 packs. We have already complained about this in the
4795 check_for_bare_parameter_packs call, so just replace
4796 these types with ERROR_MARK_NODE. */
4799 }
4803 }
4805 /* Check for bare parameter packs in the return type and the
4806 exception specifiers. */
4808 /* Errors were already issued, set return type to int
4809 as the frontend doesn't expect error_mark_node as
4810 the return type. */
4814 }
4816 {
4819 }
4830 {
4835 /* If DECL is a TYPE_DECL for a class-template, then there won't
4836 be DECL_LANG_SPECIFIC. The information equivalent to
4837 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
4841 {
4842 /* Since a template declaration already existed for this
4843 class-type, we must be redeclaring it here. Make sure
4844 that the redeclaration is valid. */
4846 current_template_parms);
4847 /* We don't need to create a new TEMPLATE_DECL; just use the
4848 one we already had. */
4850 }
4851 else
4852 {
4854 member_template_p);
4859 {
4860 /* A specialization of a member template of a template
4861 class. */
4865 }
4866 }
4867 }
4868 else
4869 {
4875 {
4878 }
4886 {
4887 tree new_tmpl;
4889 /* The declaration is a specialization of a member
4890 template, declared outside the class. Therefore, the
4891 innermost template arguments will be NULL, so we
4892 replace them with the arguments determined by the
4893 earlier call to check_explicit_specialization. */
4896 new_tmpl
4898 member_template_p);
4908 args,
4911 }
4913 /* Make sure the template headers we got make sense. */
4918 {
4921 }
4922 else
4924 {
4929 {
4933 else
4938 }
4943 /* Can happen in erroneous input. */
4945 else
4949 }
4951 /* Check that the parms are used in the appropriate qualifying scopes
4952 in the declarator. */
4956 {
4962 /* Avoid crash in import_export_decl. */
4965 }
4966 }
4971 /* Push template declarations for global functions and types. Note
4972 that we do not try to push a global template friend declared in a
4973 template class; such a thing may well depend on the template
4974 parameters of the class. */
4977 {
4982 /* Hide template friend classes that haven't been declared yet. */
4984 {
4987 }
4988 }
4991 {
4997 {
5000 /* It is a conversion operator. See if the type converted to
5001 depends on innermost template operands. */
5004 depth))
5006 }
5008 /* Give template template parms a DECL_CONTEXT of the template
5009 for which they are a parameter. */
5012 {
5016 }
5017 }
5019 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5020 back to its most general template. If TMPL is a specialization,
5021 ARGS may only have the innermost set of arguments. Add the missing
5022 argument levels if necessary. */
5034 }
5036 tree
5038 {
5040 }
5042 /* Called when a class template TYPE is redeclared with the indicated
5043 template PARMS, e.g.:
5045 template <class T> struct S;
5046 template <class T> struct S {}; */
5048 bool
5050 {
5051 tree tmpl;
5052 tree tmpl_parms;
5056 {
5059 }
5063 /* The type is nested in some template class. Nothing to worry
5064 about here; there are no new template parameters for the nested
5065 type. */
5069 {
5071 tmpl);
5073 }
5079 {
5089 }
5092 {
5093 tree tmpl_parm;
5094 tree parm;
5095 tree tmpl_default;
5096 tree parm_default;
5110 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5111 TEMPLATE_DECL. */
5121 {
5125 }
5128 {
5129 /* We have in [temp.param]:
5131 A template-parameter may not be given default arguments
5132 by two different declarations in the same scope. */
5137 }
5140 /* Update the previous template parameters (which are the ones
5141 that will really count) with the new default value. */
5144 /* Update the new parameters, too; they'll be used as the
5145 parameters for any members. */
5147 }
5150 }
5152 /* Simplify EXPR if it is a non-dependent expression. Returns the
5153 (possibly simplified) expression. */
5155 static tree
5157 {
5161 /* If we're in a template, but EXPR isn't value dependent, simplify
5162 it. We're supposed to treat:
5164 template <typename T> void f(T[1 + 1]);
5165 template <typename T> void f(T[2]);
5167 as two declarations of the same function, for example. */
5172 {
5173 HOST_WIDE_INT saved_processing_template_decl;
5179 complain,
5184 }
5186 }
5188 tree
5190 {
5192 }
5194 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5195 must be a function or a pointer-to-function type, as specified
5196 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5197 and check that the resulting function has external linkage. */
5199 static tree
5201 {
5215 /* [temp.arg.nontype]/1
5217 A template-argument for a non-type, non-template template-parameter
5218 shall be one of:
5219 [...]
5220 -- the address of an object or function with external linkage. */
5222 {
5227 }
5230 }
5232 /* Subroutine of convert_nontype_argument.
5233 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5234 Emit an error otherwise. */
5236 static bool
5238 tsubst_flags_t complain)
5239 {
5244 {
5248 }
5250 }
5252 /* Returns TRUE iff the address of OP is value-dependent.
5254 14.6.2.4 [temp.dep.temp]:
5255 A non-integral non-type template-argument is dependent if its type is
5256 dependent or it has either of the following forms
5257 qualified-id
5258 & qualified-id
5259 and contains a nested-name-specifier which specifies a class-name that
5260 names a dependent type.
5262 We generalize this to just say that the address of a member of a
5263 dependent class is value-dependent; the above doesn't cover the
5264 address of a static data member named with an unqualified-id. */
5266 static bool
5268 {
5269 /* We could use get_inner_reference here, but there's no need;
5270 this is only relevant for template non-type arguments, which
5271 can only be expressed as &id-expression. */
5273 {
5277 }
5280 }
5282 /* The next set of functions are used for providing helpful explanatory
5283 diagnostics for failed overload resolution. Their messages should be
5284 indented by two spaces for consistency with the messages in
5285 call.c */
5287 static int
5289 {
5291 }
5293 static int
5295 {
5300 }
5302 static int
5304 {
5306 }
5308 static int
5310 {
5316 }
5318 static int
5320 {
5324 }
5326 static int
5328 {
5331 " template parameter %qD is not a parameter pack, but "
5335 }
5337 static int
5339 {
5342 " template argument %qE does not match "
5346 }
5348 static int
5350 {
5354 }
5356 static int
5358 {
5364 }
5366 static int
5368 {
5374 }
5376 static int
5378 {
5381 " variable-sized array type %qT is not "
5383 arg);
5385 }
5387 static int
5389 {
5393 arg);
5395 }
5397 static int
5399 {
5406 }
5408 static int
5410 {
5412 }
5414 static int
5416 {
5418 }
5420 static int
5423 {
5428 }
5430 static int
5433 {
5436 {
5444 }
5446 }
5448 static int
5450 {
5453 " template parameters of a template template argument are "
5456 }
5458 static int
5460 {
5466 }
5468 static int
5470 {
5475 }
5477 static int
5479 {
5483 arg);
5485 }
5487 /* Attempt to convert the non-type template parameter EXPR to the
5488 indicated TYPE. If the conversion is successful, return the
5489 converted value. If the conversion is unsuccessful, return
5490 NULL_TREE if we issued an error message, or error_mark_node if we
5491 did not. We issue error messages for out-and-out bad template
5492 parameters, but not simply because the conversion failed, since we
5493 might be just trying to do argument deduction. Both TYPE and EXPR
5494 must be non-dependent.
5496 The conversion follows the special rules described in
5497 [temp.arg.nontype], and it is much more strict than an implicit
5498 conversion.
5500 This function is called twice for each template argument (see
5501 lookup_template_class for a more accurate description of this
5502 problem). This means that we need to handle expressions which
5503 are not valid in a C++ source, but can be created from the
5504 first call (for instance, casts to perform conversions). These
5505 hacks can go away after we fix the double coercion problem. */
5507 static tree
5509 {
5510 tree expr_type;
5512 /* Detect immediately string literals as invalid non-type argument.
5513 This special-case is not needed for correctness (we would easily
5514 catch this later), but only to provide better diagnostic for this
5515 common user mistake. As suggested by DR 100, we do not mention
5516 linkage issues in the diagnostic as this is not the point. */
5517 /* FIXME we're making this OK. */
5519 {
5525 }
5527 /* Add the ADDR_EXPR now for the benefit of
5528 value_dependent_expression_p. */
5533 /* If we are in a template, EXPR may be non-dependent, but still
5534 have a syntactic, rather than semantic, form. For example, EXPR
5535 might be a SCOPE_REF, rather than the VAR_DECL to which the
5536 SCOPE_REF refers. Preserving the qualifying scope is necessary
5537 so that access checking can be performed when the template is
5538 instantiated -- but here we need the resolved form so that we can
5539 convert the argument. */
5550 else
5553 /* HACK: Due to double coercion, we can get a
5554 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5555 which is the tree that we built on the first call (see
5556 below when coercing to reference to object or to reference to
5557 function). We just strip everything and get to the arg.
5558 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5559 for examples. */
5561 {
5567 {
5568 /* ??? Maybe we could use convert_from_reference here, but we
5569 would need to relax its constraints because the NOP_EXPR
5570 could actually change the type to something more cv-qualified,
5571 and this is not folded by convert_from_reference. */
5582 }
5583 }
5585 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5586 parameter is a pointer to object, through decay and
5587 qualification conversion. Let's strip everything. */
5589 {
5593 /* Skip the ADDR_EXPR only if it is part of the decay for
5594 an array. Otherwise, it is part of the original argument
5595 in the source code. */
5599 }
5601 /* [temp.arg.nontype]/5, bullet 1
5603 For a non-type template-parameter of integral or enumeration type,
5604 integral promotions (_conv.prom_) and integral conversions
5605 (_conv.integral_) are applied. */
5607 {
5616 /* Notice that there are constant expressions like '4 % 0' which
5617 do not fold into integer constants. */
5619 {
5621 {
5629 /* else cxx_constant_value complained but gave us
5630 a real constant, so go ahead. */
5632 }
5633 else
5635 }
5636 }
5637 /* [temp.arg.nontype]/5, bullet 2
5639 For a non-type template-parameter of type pointer to object,
5640 qualification conversions (_conv.qual_) and the array-to-pointer
5641 conversion (_conv.array_) are applied. */
5643 {
5644 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
5646 A template-argument for a non-type, non-template template-parameter
5647 shall be one of: [...]
5649 -- the name of a non-type template-parameter;
5650 -- the address of an object or function with external linkage, [...]
5651 expressed as "& id-expression" where the & is optional if the name
5652 refers to a function or array, or if the corresponding
5653 template-parameter is a reference.
5655 Here, we do not care about functions, as they are invalid anyway
5656 for a parameter of type pointer-to-object. */
5659 /* Non-type template parameters are OK. */
5660 ;
5663 {
5665 {
5667 "because %qD is a variable, not the address of "
5671 }
5672 /* Other values, like integer constants, might be valid
5673 non-type arguments of some other type. */
5675 }
5676 else
5677 {
5678 tree decl;
5683 {
5688 }
5690 {
5695 }
5696 }
5705 }
5706 /* [temp.arg.nontype]/5, bullet 3
5708 For a non-type template-parameter of type reference to object, no
5709 conversions apply. The type referred to by the reference may be more
5710 cv-qualified than the (otherwise identical) type of the
5711 template-argument. The template-parameter is bound directly to the
5712 template-argument, which must be an lvalue. */
5714 {
5716 expr_type))
5720 {
5724 }
5727 {
5731 }
5733 /* [temp.arg.nontype]/1
5735 A template-argument for a non-type, non-template template-parameter
5736 shall be one of: [...]
5738 -- the address of an object or function with external linkage. */
5741 {
5744 {
5746 "because a reference variable does not have a constant "
5749 }
5750 }
5753 {
5758 }
5761 {
5766 }
5769 }
5770 /* [temp.arg.nontype]/5, bullet 4
5772 For a non-type template-parameter of type pointer to function, only
5773 the function-to-pointer conversion (_conv.func_) is applied. If the
5774 template-argument represents a set of overloaded functions (or a
5775 pointer to such), the matching function is selected from the set
5776 (_over.over_). */
5778 {
5779 /* If the argument is a template-id, we might not have enough
5780 context information to decay the pointer. */
5782 {
5786 }
5793 {
5797 }
5798 }
5799 /* [temp.arg.nontype]/5, bullet 5
5801 For a non-type template-parameter of type reference to function, no
5802 conversions apply. If the template-argument represents a set of
5803 overloaded functions, the matching function is selected from the set
5804 (_over.over_). */
5806 {
5808 {
5813 }
5820 }
5821 /* [temp.arg.nontype]/5, bullet 6
5823 For a non-type template-parameter of type pointer to member function,
5824 no conversions apply. If the template-argument represents a set of
5825 overloaded member functions, the matching member function is selected
5826 from the set (_over.over_). */
5828 {
5833 /* [temp.arg.nontype] bullet 1 says the pointer to member
5834 expression must be a pointer-to-member constant. */
5838 /* There is no way to disable standard conversions in
5839 resolve_address_of_overloaded_function (called by
5840 instantiate_type). It is possible that the call succeeded by
5841 converting &B::I to &D::I (where B is a base of D), so we need
5842 to reject this conversion here.
5844 Actually, even if there was a way to disable standard conversions,
5845 it would still be better to reject them here so that we can
5846 provide a superior diagnostic. */
5848 {
5852 /* If we are just one standard conversion off, explain. */
5857 }
5858 }
5859 /* [temp.arg.nontype]/5, bullet 7
5861 For a non-type template-parameter of type pointer to data member,
5862 qualification conversions (_conv.qual_) are applied. */
5864 {
5865 /* [temp.arg.nontype] bullet 1 says the pointer to member
5866 expression must be a pointer-to-member constant. */
5873 }
5874 /* A template non-type parameter must be one of the above. */
5875 else
5878 /* Sanity check: did we actually convert the argument to the
5879 right type? */
5883 }
5885 /* Subroutine of coerce_template_template_parms, which returns 1 if
5886 PARM_PARM and ARG_PARM match using the rule for the template
5887 parameters of template template parameters. Both PARM and ARG are
5888 template parameters; the rest of the arguments are the same as for
5889 coerce_template_template_parms.
5890 */
5891 static int
5893 tree arg,
5894 tsubst_flags_t complain,
5895 tree in_decl,
5896 tree outer_args)
5897 {
5906 {
5908 /* We encounter instantiations of templates like
5909 template <template <template <class> class> class TT>
5910 class C; */
5911 {
5918 }
5919 /* Fall through. */
5924 /* Argument is a parameter pack but parameter is not. */
5929 /* The tsubst call is used to handle cases such as
5931 template <int> class C {};
5932 template <class T, template <T> class TT> class D {};
5933 D<int, C> d;
5935 i.e. the parameter list of TT depends on earlier parameters. */
5937 && !same_type_p
5944 /* Argument is a parameter pack but parameter is not. */
5951 }
5954 }
5957 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
5958 template template parameters. Both PARM_PARMS and ARG_PARMS are
5959 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
5960 or PARM_DECL.
5962 Consider the example:
5963 template <class T> class A;
5964 template<template <class U> class TT> class B;
5966 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
5967 the parameters to A, and OUTER_ARGS contains A. */
5969 static int
5971 tree arg_parms,
5972 tsubst_flags_t complain,
5973 tree in_decl,
5974 tree outer_args)
5975 {
5986 /* Determine whether we have a parameter pack at the end of the
5987 template template parameter's template parameter list. */
5989 {
5996 {
6010 }
6011 }
6017 /* Check all of the template parameters except the parameter pack at
6018 the end (if any). */
6020 {
6029 outer_args))
6032 }
6035 {
6036 /* Check each of the template parameters in the template
6037 argument against the template parameter pack at the end of
6038 the template template parameter. */
6045 {
6052 outer_args))
6054 }
6055 }
6058 }
6060 /* Verifies that the deduced template arguments (in TARGS) for the
6061 template template parameters (in TPARMS) represent valid bindings,
6062 by comparing the template parameter list of each template argument
6063 to the template parameter list of its corresponding template
6064 template parameter, in accordance with DR150. This
6065 routine can only be called after all template arguments have been
6066 deduced. It will return TRUE if all of the template template
6067 parameter bindings are okay, FALSE otherwise. */
6068 bool
6070 {
6074 /* We're dealing with template parms in this process. */
6080 {
6085 {
6090 {
6091 /* Look inside the argument pack. */
6094 }
6097 {
6101 /* Extract the next argument from the argument
6102 pack. */
6106 /* Look at the pattern of the pack expansion. */
6109 /* Extract the template parameters from the template
6110 argument. */
6116 /* Verify that we can coerce the template template
6117 parameters from the template argument to the template
6118 parameter. This requires an exact match. */
6120 && !coerce_template_template_parms
6122 targ_parms,
6123 tf_none,
6124 tparm,
6125 targs))
6126 {
6129 }
6130 }
6131 }
6132 }
6134 out:
6138 }
6140 /* Since type attributes aren't mangled, we need to strip them from
6141 template type arguments. */
6143 static tree
6145 {
6146 tree mv;
6153 {
6158 }
6160 }
6162 /* Convert the indicated template ARG as necessary to match the
6163 indicated template PARM. Returns the converted ARG, or
6164 error_mark_node if the conversion was unsuccessful. Error and
6165 warning messages are issued under control of COMPLAIN. This
6166 conversion is for the Ith parameter in the parameter list. ARGS is
6167 the full set of template arguments deduced so far. */
6169 static tree
6171 tree arg,
6172 tree args,
6173 tsubst_flags_t complain,
6175 tree in_decl)
6176 {
6177 tree orig_arg;
6178 tree val;
6183 {
6184 /* The template argument was the name of some
6185 member function. That's usually
6186 invalid, but static members are OK. In any
6187 case, grab the underlying fields/functions
6188 and issue an error later if required. */
6191 }
6199 /* When determining whether an argument pack expansion is a template,
6200 look at the pattern. */
6204 /* Deal with an injected-class-name used as a template template arg. */
6206 {
6209 {
6219 }
6220 }
6222 is_tmpl_type =
6237 {
6243 typename_type,
6247 }
6249 {
6251 {
6253 {
6263 else
6265 }
6266 }
6268 }
6270 {
6272 {
6278 else
6280 }
6282 }
6285 {
6287 {
6289 /* The number of argument required is not known yet.
6290 Just accept it for now. */
6292 else
6293 {
6295 tree argparm;
6301 args))
6302 {
6305 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6306 TEMPLATE_DECL. */
6308 {
6313 }
6314 }
6315 else
6316 {
6318 {
6324 }
6327 }
6328 }
6329 }
6330 else
6332 /* We only form one instance of each template specialization.
6333 Therefore, if we use a non-canonical variant (i.e., a
6334 typedef), any future messages referring to the type will use
6335 the typedef, which is confusing if those future uses do not
6336 themselves also use the typedef. */
6339 }
6340 else
6341 {
6348 {
6351 else
6352 {
6353 /* Not sure if this is reachable, but it doesn't hurt
6354 to be robust. */
6357 }
6358 }
6360 /* We used to call digest_init here. However, digest_init
6361 will report errors, which we don't want when complain
6362 is zero. More importantly, digest_init will try too
6363 hard to convert things: for example, `0' should not be
6364 converted to pointer type at this point according to
6365 the standard. Accepting this is not merely an
6366 extension, since deciding whether or not these
6367 conversions can occur is part of determining which
6368 function template to call, or whether a given explicit
6369 argument specification is valid. */
6371 else
6380 {
6381 /* Strip typedefs from the SCOPE_REF. */
6384 complain);
6387 }
6388 }
6391 }
6393 /* Coerces the remaining template arguments in INNER_ARGS (from
6394 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6395 Returns the coerced argument pack. PARM_IDX is the position of this
6396 parameter in the template parameter list. ARGS is the original
6397 template argument list. */
6398 static tree
6401 tree args,
6402 tree inner_args,
6404 tree new_args,
6406 tree in_decl,
6407 tsubst_flags_t complain)
6408 {
6411 tree packed_args;
6412 tree argument_pack;
6422 {
6423 /* When the template parameter is a non-type template
6424 parameter pack whose type uses parameter packs, we need
6425 to look at each of the template arguments
6426 separately. Build a vector of the types for these
6427 non-type template parameters in PACKED_TYPES. */
6428 tree expansion
6436 /* Check that we have the right number of arguments. */
6440 {
6441 int needed_parms
6446 }
6448 /* If we aren't able to check the actual arguments now
6449 (because they haven't been expanded yet), we can at least
6450 verify that all of the types used for the non-type
6451 template parameter pack are, in fact, valid for non-type
6452 template parameters. */
6455 {
6458 {
6462 }
6463 }
6464 }
6466 /* Convert the remaining arguments, which will be a part of the
6467 parameter pack "parm". */
6469 {
6474 {
6475 /* When we have a vector of types (corresponding to the
6476 non-type template parameter pack that uses parameter
6477 packs in its type, as mention above), and the
6478 argument is not an expansion (which expands to a
6479 currently unknown number of arguments), clone the
6480 parm and give it the next type in PACKED_TYPES. */
6484 }
6489 in_decl);
6493 }
6498 else
6499 {
6504 }
6507 #ifdef ENABLE_CHECKING
6510 #endif
6512 }
6514 /* Convert all template arguments to their appropriate types, and
6515 return a vector containing the innermost resulting template
6516 arguments. If any error occurs, return error_mark_node. Error and
6517 warning messages are issued under control of COMPLAIN.
6519 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6520 for arguments not specified in ARGS. Otherwise, if
6521 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
6522 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
6523 USE_DEFAULT_ARGS is false, then all arguments must be specified in
6524 ARGS. */
6526 static tree
6528 tree args,
6529 tree in_decl,
6530 tsubst_flags_t complain,
6533 {
6535 tree inner_args;
6536 tree new_args;
6537 tree new_inner_args;
6541 /* When used as a boolean value, indicates whether this is a
6542 variadic template parameter list. Since it's an int, we can also
6543 subtract it from nparms to get the number of non-variadic
6544 parameters. */
6553 /* Determine if there are any parameter packs. */
6555 {
6561 }
6564 /* If there are no parameters that follow a parameter pack, we need to
6565 expand any argument packs so that we can deduce a parameter pack from
6566 some non-packed args followed by an argument pack, as in variadic85.C.
6567 If there are such parameters, we need to leave argument packs intact
6568 so the arguments are assigned properly. This can happen when dealing
6569 with a nested class inside a partial specialization of a class
6570 template, as in variadic92.C, or when deducing a template parameter pack
6571 from a sub-declarator, as in variadic114.C. */
6578 && require_all_args
6579 && (!use_default_args
6582 {
6584 {
6586 {
6590 }
6591 else
6597 }
6600 }
6602 /* We need to evaluate the template arguments, even though this
6603 template-id may be nested within a "sizeof". */
6611 {
6612 tree arg;
6613 tree parm;
6615 /* Get the Ith template parameter. */
6619 {
6622 }
6624 /* Calculate the next argument. */
6627 else
6632 {
6633 /* All remaining arguments will be placed in the
6634 template parameter pack PARM. */
6640 /* Store this argument. */
6642 lost++;
6645 /* We are done with all of the arguments. */
6649 }
6651 {
6653 {
6655 {
6656 /* FIXME this restriction was removed by N2555; see
6657 bug 35722. */
6658 /* If ARG is a pack expansion, but PARM is not a
6659 template parameter pack (if it were, we would have
6660 handled it above), we're trying to expand into a
6661 fixed-length argument list. */
6665 else
6668 }
6670 }
6671 }
6673 {
6674 /* There must be a default arg in this case. */
6677 /* The position of the first default template argument,
6678 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
6679 Record that. */
6682 }
6683 else
6687 {
6690 }
6692 /* This only occurs if there was an error in the template
6693 parameter list itself (which we would already have
6694 reported) that we are trying to recover from, e.g., a class
6695 template with a parameter list such as
6696 template<typename..., typename>. */
6698 else
6704 lost++;
6706 }
6713 #ifdef ENABLE_CHECKING
6717 #endif
6720 }
6722 /* Returns 1 if template args OT and NT are equivalent. */
6724 static int
6726 {
6733 /* For member templates */
6740 {
6757 }
6759 {
6760 /* We get here probably because we are in the middle of substituting
6761 into the pattern of a pack expansion. In that case the
6762 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
6763 interested in. So we want to use the initial pack argument for
6764 the comparison. */
6769 }
6774 else
6776 }
6778 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
6779 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
6780 NEWARG_PTR with the offending arguments if they are non-NULL. */
6782 static int
6785 {
6792 {
6797 {
6803 }
6804 }
6806 }
6808 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
6809 of template arguments. Returns 0 otherwise. */
6811 int
6813 {
6815 }
6817 static void
6819 {
6829 /* We are called both from instantiate_decl, where we've already had a
6830 tinst_level pushed, and instantiate_template, where we haven't.
6831 Compensate. */
6842 else
6851 }
6854 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
6855 ARGLIST. Valid choices for FNS are given in the cp-tree.def
6856 documentation for TEMPLATE_ID_EXPR. */
6858 tree
6860 {
6861 tree type;
6869 {
6872 }
6875 {
6877 unknown_type_node,
6879 arglist);
6881 }
6888 }
6890 /* Within the scope of a template class S<T>, the name S gets bound
6891 (in build_self_reference) to a TYPE_DECL for the class, not a
6892 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
6893 or one of its enclosing classes, and that type is a template,
6894 return the associated TEMPLATE_DECL. Otherwise, the original
6895 DECL is returned.
6897 Also handle the case when DECL is a TREE_LIST of ambiguous
6898 injected-class-names from different bases. */
6900 tree
6902 {
6906 /* DR 176: A lookup that finds an injected-class-name (10.2
6907 [class.member.lookup]) can result in an ambiguity in certain cases
6908 (for example, if it is found in more than one base class). If all of
6909 the injected-class-names that are found refer to specializations of
6910 the same class template, and if the name is followed by a
6911 template-argument-list, the reference refers to the class template
6912 itself and not a specialization thereof, and is not ambiguous. */
6914 {
6917 {
6923 }
6926 else
6928 }
6934 }
6936 /* Given an IDENTIFIER_NODE (type TEMPLATE_DECL) and a chain of
6937 parameters, find the desired type.
6939 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
6941 IN_DECL, if non-NULL, is the template declaration we are trying to
6942 instantiate.
6944 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
6945 the class we are looking up.
6947 Issue error and warning messages under control of COMPLAIN.
6949 If the template class is really a local class in a template
6950 function, then the FUNCTION_CONTEXT is the function in which it is
6951 being instantiated.
6953 ??? Note that this function is currently called *twice* for each
6954 template-id: the first time from the parser, while creating the
6955 incomplete type (finish_template_type), and the second type during the
6956 real instantiation (instantiate_template_class). This is surely something
6957 that we want to avoid. It also causes some problems with argument
6958 coercion (see convert_nontype_argument for more information on this). */
6960 static tree
6963 {
6965 tree t;
6968 spec_entry elt;
6969 hashval_t hash;
6972 {
6976 else
6977 {
6984 }
6987 }
6989 {
6992 /* If we are declaring a constructor, say A<T>::A<T>, we will get
6993 an implicit typename for the second A. Deal with it. */
6998 {
7001 }
7002 }
7005 {
7008 }
7012 {
7016 }
7018 /* Issue an error message if we didn't find a template. */
7020 {
7024 }
7027 /* Make sure it's a user visible template, if it was named by
7028 the user. */
7031 {
7033 {
7037 }
7039 }
7044 {
7045 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7046 template arguments */
7048 tree parm;
7049 tree arglist2;
7050 tree outer;
7054 /* Consider an example where a template template parameter declared as
7056 template <class T, class U = std::allocator<T> > class TT
7058 The template parameter level of T and U are one level larger than
7059 of TT. To proper process the default argument of U, say when an
7060 instantiation `TT<int>' is seen, we need to build the full
7061 arguments containing {int} as the innermost level. Outer levels,
7062 available when not appearing as default template argument, can be
7063 obtained from the arguments of the enclosing template.
7065 Suppose that TT is later substituted with std::vector. The above
7066 instantiation is `TT<int, std::allocator<T> >' with TT at
7067 level 1, and T at level 2, while the template arguments at level 1
7068 becomes {std::vector} and the inner level 2 is {int}. */
7074 /* This is an argument of the current template, so we haven't set
7075 DECL_CONTEXT yet. */
7082 complain,
7092 }
7093 else
7094 {
7096 tree gen_tmpl;
7097 tree type_decl;
7110 {
7111 /* We've been given an incomplete set of template arguments.
7112 For example, given:
7114 template <class T> struct S1 {
7115 template <class U> struct S2 {};
7116 template <class U> struct S2<U*> {};
7117 };
7119 we will be called with an ARGLIST of `U*', but the
7120 TEMPLATE will be `template <class T> template
7121 <class U> struct S1<T>::S2'. We must fill in the missing
7122 arguments. */
7123 arglist
7125 arglist);
7127 }
7129 /* Now we should have enough arguments. */
7132 /* From here on, we're only interested in the most general
7133 template. */
7135 /* Calculate the BOUND_ARGS. These will be the args that are
7136 actually tsubst'd into the definition to create the
7137 instantiation. */
7139 {
7140 /* We have multiple levels of arguments to coerce, at once. */
7150 {
7151 tree a;
7155 complain,
7158 else
7159 /* Outer levels should have already been coerced. */
7162 /* Don't process further if one of the levels fails. */
7164 {
7165 /* Restore the ARGLIST to its full size. */
7168 }
7172 /* We temporarily reduce the length of the ARGLIST so
7173 that coerce_template_parms will see only the arguments
7174 corresponding to the template parameters it is
7175 examining. */
7177 }
7179 /* Restore the ARGLIST to its full size. */
7183 }
7184 else
7185 arglist
7188 gen_tmpl,
7189 complain,
7194 /* We were unable to bind the arguments. */
7197 /* In the scope of a template class, explicit references to the
7198 template class refer to the type of the template, not any
7199 instantiation of it. For example, in:
7201 template <class T> class C { void f(C<T>); }
7203 the `C<T>' is just the same as `C'. Outside of the
7204 class, however, such a reference is an instantiation. */
7208 /* comp_template_args is expensive, check it last. */
7210 arglist))
7213 /* If we already have this specialization, return it. */
7225 /* If the deduced arguments are invalid, then the binding
7226 failed. */
7230 complain))
7237 {
7242 }
7249 /* Create the type. */
7251 {
7253 {
7259 }
7260 else
7261 {
7262 /* We don't want to call start_enum for this type, since
7263 the values for the enumeration constants may involve
7264 template parameters. And, no one should be interested
7265 in the enumeration constants for such a type. */
7268 }
7272 }
7273 else
7274 {
7281 /* A local class. Make sure the decl gets registered properly. */
7286 /* This instantiation is another name for the primary
7287 template type. Set the TYPE_CANONICAL field
7288 appropriately. */
7291 /* Some of the template arguments require structural
7292 equality testing, so this template class requires
7293 structural equality testing. */
7295 }
7297 /* If we called start_enum or pushtag above, this information
7298 will already be set up. */
7300 {
7307 }
7308 else
7316 {
7319 }
7321 /* Let's consider the explicit specialization of a member
7322 of a class template specialization that is implicitely instantiated,
7323 e.g.:
7324 template<class T>
7325 struct S
7326 {
7327 template<class U> struct M {}; //#0
7328 };
7330 template<>
7331 template<>
7332 struct S<int>::M<char> //#1
7333 {
7334 int i;
7335 };
7336 [temp.expl.spec]/4 says this is valid.
7338 In this case, when we write:
7339 S<int>::M<char> m;
7341 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
7342 the one of #0.
7344 When we encounter #1, we want to store the partial instantiation
7345 of M (template<class T> S<int>::M<T>) in it's CLASSTYPE_TI_TEMPLATE.
7347 For all cases other than this "explicit specialization of member of a
7348 class template", we just want to store the most general template into
7349 the CLASSTYPE_TI_TEMPLATE of M.
7351 This case of "explicit specialization of member of a class template"
7352 only happens when:
7353 1/ the enclosing class is an instantiation of, and therefore not
7354 the same as, the context of the most general template, and
7355 2/ we aren't looking at the partial instantiation itself, i.e.
7356 the innermost arguments are not the same as the innermost parms of
7357 the most general template.
7359 So it's only when 1/ and 2/ happens that we want to use the partial
7360 instantiation of the member template in lieu of its most general
7361 template. */
7365 /* the enclosing class must be an instantiation... */
7368 {
7369 tree partial_inst_args;
7372 partial_inst_args =
7378 use_partial_inst_tmpl =
7379 /*...and we must not be looking at the partial instantiation
7380 itself. */
7382 partial_inst_args);
7383 }
7386 /* This case is easy; there are no member templates involved. */
7388 else
7389 {
7390 /* This is a full instantiation of a member template. Find
7391 the partial instantiation of which this is an instance. */
7393 /* Temporarily reduce by one the number of levels in the ARGLIST
7394 so as to avoid comparing the last set of arguments. */
7399 }
7409 /* Note this use of the partial instantiation so we can check it
7410 later in maybe_process_partial_specialization. */
7416 /* Now that the type has been registered on the instantiations
7417 list, we set up the enumerators. Because the enumeration
7418 constants may involve the enumeration type itself, we make
7419 sure to register the type first, and then create the
7420 constants. That way, doing tsubst_expr for the enumeration
7421 constants won't result in recursive calls here; we'll find
7422 the instantiation and exit above. */
7426 /* If the type makes use of template parameters, the
7427 code that generates debugging information will crash. */
7430 /* Possibly limit visibility based on template args. */
7435 }
7436 }
7438 /* Wrapper for lookup_template_class_1. */
7440 tree
7443 {
7444 tree ret;
7450 }
7451 \f
7452 struct pair_fn_data
7453 {
7454 tree_fn_t fn;
7456 /* True when we should also visit template parameters that occur in
7457 non-deduced contexts. */
7460 };
7462 /* Called from for_each_template_parm via walk_tree. */
7464 static tree
7466 {
7479 {
7483 /* Fall through. */
7506 /* Since we're not going to walk subtrees, we have to do this
7507 explicitly here. */
7511 /* Fall through. */
7514 /* Check the return type. */
7519 /* Check the parameter types. Since default arguments are not
7520 instantiated until they are needed, the TYPE_ARG_TYPES may
7521 contain expressions that involve template parameters. But,
7522 no-one should be looking at them yet. And, once they're
7523 instantiated, they don't contain template parameters, so
7524 there's no point in looking at them then, either. */
7525 {
7526 tree parm;
7533 /* Since we've already handled the TYPE_ARG_TYPES, we don't
7534 want walk_tree walking into them itself. */
7536 }
7554 /* Fall through. */
7570 /* Record template parameters such as `T' inside `TT<T>'. */
7574 /* Fall through. */
7586 /* A template template parameter is encountered. */
7592 /* Already substituted template template parameter */
7615 /* If there's no type, then this thing must be some expression
7616 involving template parameters. */
7637 }
7639 /* We didn't find any template parameters we liked. */
7641 }
7643 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
7644 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
7645 call FN with the parameter and the DATA.
7646 If FN returns nonzero, the iteration is terminated, and
7647 for_each_template_parm returns 1. Otherwise, the iteration
7648 continues. If FN never returns a nonzero value, the value
7649 returned by for_each_template_parm is 0. If FN is NULL, it is
7650 considered to be the function which always returns 1.
7652 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
7653 parameters that occur in non-deduced contexts. When false, only
7654 visits those template parameters that can be deduced. */
7656 static int
7660 {
7664 /* Set up. */
7669 /* Walk the tree. (Conceptually, we would like to walk without
7670 duplicates, but for_each_template_parm_r recursively calls
7671 for_each_template_parm, so we would need to reorganize a fair
7672 bit to use walk_tree_without_duplicates, so we keep our own
7673 visited list.) */
7676 else
7679 for_each_template_parm_r,
7683 /* Clean up. */
7685 {
7688 }
7691 }
7693 /* Returns true if T depends on any template parameter. */
7695 int
7697 {
7724 else
7725 {
7728 }
7733 }
7735 /* Returns true if T depends on any template parameter with level LEVEL. */
7737 int
7739 {
7742 }
7744 /* Returns TRUE iff INST is an instantiation we don't need to do in an
7745 ill-formed translation unit, i.e. a variable or function that isn't
7746 usable in a constant expression. */
7750 {
7754 }
7756 /* Returns TRUE iff we should refuse to instantiate DECL because it's
7757 neglectable and instantiated from within an erroneous instantiation. */
7759 static bool
7761 {
7772 }
7776 #ifdef GATHER_STATISTICS
7778 #endif
7781 /* We're starting to instantiate D; record the template instantiation context
7782 for diagnostics and to restore it later. */
7784 int
7786 {
7790 {
7796 else
7804 }
7806 /* If the current instantiation caused problems, don't let it instantiate
7807 anything else. Do allow deduction substitution and decls usable in
7808 constant expressions. */
7821 #ifdef GATHER_STATISTICS
7824 #endif
7827 }
7829 /* We're done instantiating this template; return to the instantiation
7830 context. */
7832 void
7834 {
7835 /* Restore the filename and line number stashed away when we started
7836 this instantiation. */
7840 }
7842 /* We're instantiating a deferred template; restore the template
7843 instantiation context in which the instantiation was requested, which
7844 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
7846 static tree
7848 {
7860 }
7862 /* Returns the TINST_LEVEL which gives the original instantiation
7863 context. */
7867 {
7873 }
7875 /* Returns TRUE if PARM is a parameter of the template TEMPL. */
7877 bool
7879 {
7880 tree parms;
7893 {
7899 }
7902 }
7904 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
7905 vector of template arguments, as for tsubst.
7907 Returns an appropriate tsubst'd friend declaration. */
7909 static tree
7911 {
7912 tree new_friend;
7917 /* This was a friend declared with an explicit template
7918 argument list, e.g.:
7920 friend void f<>(T);
7922 to indicate that f was a template instantiation, not a new
7923 function declaration. Now, we have to figure out what
7924 instantiation of what template. */
7925 {
7927 tree new_args;
7928 tree tmpl;
7931 /* Friend functions are looked up in the containing namespace scope.
7932 We must enter that scope, to avoid finding member functions of the
7933 current class with same name. */
7948 tsk_none);
7950 }
7954 /* The NEW_FRIEND will look like an instantiation, to the
7955 compiler, but is not an instantiation from the point of view of
7956 the language. For example, we might have had:
7958 template <class T> struct S {
7959 template <class U> friend void f(T, U);
7960 };
7962 Then, in S<int>, template <class U> void f(int, U) is not an
7963 instantiation of anything. */
7969 {
7973 }
7975 /* The mangled name for the NEW_FRIEND is incorrect. The function
7976 is not a template instantiation and should not be mangled like
7977 one. Therefore, we forget the mangling here; we'll recompute it
7978 later if we need it. */
7980 {
7983 }
7986 {
7987 tree old_decl;
7988 tree new_friend_template_info;
7989 tree new_friend_result_template_info;
7990 tree ns;
7993 /* We must save some information from NEW_FRIEND before calling
7994 duplicate decls since that function will free NEW_FRIEND if
7995 possible. */
7997 new_friend_is_defn =
8002 {
8003 /* This declaration is a `primary' template. */
8006 new_friend_result_template_info
8008 }
8009 else
8012 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8016 /* Inside pushdecl_namespace_level, we will push into the
8017 current namespace. However, the friend function should go
8018 into the namespace of the template. */
8028 {
8029 /* This new friend declaration matched an existing
8030 declaration. For example, given:
8032 template <class T> void f(T);
8033 template <class U> class C {
8034 template <class T> friend void f(T) {}
8035 };
8037 the friend declaration actually provides the definition
8038 of `f', once C has been instantiated for some type. So,
8039 old_decl will be the out-of-class template declaration,
8040 while new_friend is the in-class definition.
8042 But, if `f' was called before this point, the
8043 instantiation of `f' will have DECL_TI_ARGS corresponding
8044 to `T' but not to `U', references to which might appear
8045 in the definition of `f'. Previously, the most general
8046 template for an instantiation of `f' was the out-of-class
8047 version; now it is the in-class version. Therefore, we
8048 run through all specialization of `f', adding to their
8049 DECL_TI_ARGS appropriately. In particular, they need a
8050 new set of outer arguments, corresponding to the
8051 arguments for this class instantiation.
8053 The same situation can arise with something like this:
8055 friend void f(int);
8056 template <class T> class C {
8057 friend void f(T) {}
8058 };
8060 when `C<int>' is instantiated. Now, `f(int)' is defined
8061 in the class. */
8064 /* On the other hand, if the in-class declaration does
8065 *not* provide a definition, then we don't want to alter
8066 existing definitions. We can just leave everything
8067 alone. */
8068 ;
8069 else
8070 {
8074 /* Overwrite whatever template info was there before, if
8075 any, with the new template information pertaining to
8076 the declaration. */
8080 {
8081 /* We should have called reregister_specialization in
8082 duplicate_decls. */
8087 /* Instantiate it if the global has already been used. */
8091 }
8092 else
8093 {
8094 tree t;
8096 /* Indicate that the old function template is a partial
8097 instantiation. */
8105 /* Reassign any specializations already in the hash table
8106 to the new more general template, and add the
8107 additional template args. */
8111 {
8113 spec_entry elt;
8125 register_specialization
8128 }
8130 }
8131 }
8133 /* The information from NEW_FRIEND has been merged into OLD_DECL
8134 by duplicate_decls. */
8136 }
8137 }
8138 else
8139 {
8143 /* In the code
8144 template <class T> class C {
8145 template <class U> friend void C1<U>::f (); // case 1
8146 friend void C2<T>::f (); // case 2
8147 };
8148 we only need to make sure CONTEXT is a complete type for
8149 case 2. To distinguish between the two cases, we note that
8150 CONTEXT of case 1 remains dependent type after tsubst while
8151 this isn't true for case 2. */
8161 {
8162 /* Check to see that the declaration is really present, and,
8163 possibly obtain an improved declaration. */
8169 }
8170 }
8173 }
8175 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8176 template arguments, as for tsubst.
8178 Returns an appropriate tsubst'd friend type or error_mark_node on
8179 failure. */
8181 static tree
8183 {
8184 tree friend_type;
8185 tree tmpl;
8186 tree context;
8191 {
8194 else
8196 }
8198 /* Look for a class template declaration. We look for hidden names
8199 because two friend declarations of the same template are the
8200 same. For example, in:
8202 struct A {
8203 template <typename> friend class F;
8204 };
8205 template <typename> struct B {
8206 template <typename> friend class F;
8207 };
8209 both F templates are the same. */
8214 /* But, if we don't find one, it might be because we're in a
8215 situation like this:
8217 template <class T>
8218 struct S {
8219 template <class U>
8220 friend struct S;
8221 };
8223 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8224 for `S<int>', not the TEMPLATE_DECL. */
8226 {
8229 }
8232 {
8233 /* The friend template has already been declared. Just
8234 check to see that the declarations match, and install any new
8235 default parameters. We must tsubst the default parameters,
8236 of course. We only need the innermost template parameters
8237 because that is all that redeclare_class_template will look
8238 at. */
8241 {
8242 tree parms;
8243 location_t saved_input_location;
8252 }
8255 }
8256 else
8257 {
8258 /* The friend template has not already been declared. In this
8259 case, the instantiation of the template class will cause the
8260 injection of this template into the global scope. */
8265 /* The new TMPL is not an instantiation of anything, so we
8266 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
8267 the new type because that is supposed to be the corresponding
8268 template decl, i.e., TMPL. */
8275 /* Inject this template into the global scope. */
8277 }
8280 {
8283 else
8285 }
8288 }
8290 /* Returns zero if TYPE cannot be completed later due to circularity.
8291 Otherwise returns one. */
8293 static int
8295 {
8305 else
8307 }
8309 /* Apply any attributes which had to be deferred until instantiation
8310 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
8311 ARGS, COMPLAIN, IN_DECL are as tsubst. */
8313 static void
8316 {
8318 tree t;
8323 {
8327 }
8330 {
8334 }
8335 else
8339 {
8344 {
8347 {
8350 /* If the first attribute argument is an identifier, don't
8351 pass it through tsubst. Attributes like mode, format,
8352 cleanup and several target specific attributes expect it
8353 unmodified. */
8359 {
8360 tree chain
8362 in_decl,
8367 chain);
8368 }
8369 else
8375 }
8376 else
8378 }
8381 }
8382 }
8384 /* Perform (or defer) access check for typedefs that were referenced
8385 from within the template TMPL code.
8386 This is a subroutine of instantiate_template and instantiate_class_template.
8387 TMPL is the template to consider and TARGS is the list of arguments of
8388 that template. */
8390 static void
8392 {
8393 location_t saved_location;
8406 {
8418 /* Make access check error messages point to the location
8419 of the use of the typedef. */
8423 }
8425 }
8427 static tree
8429 {
8431 tree typedecl;
8432 tree pbinfo;
8433 tree base_list;
8443 /* Figure out which template is being instantiated. */
8447 /* Determine what specialization of the original template to
8448 instantiate. */
8451 {
8454 }
8456 {
8457 /* This TYPE is actually an instantiation of a partial
8458 specialization. We replace the innermost set of ARGS with
8459 the arguments appropriate for substitution. For example,
8460 given:
8462 template <class T> struct S {};
8463 template <class T> struct S<T*> {};
8465 and supposing that we are instantiating S<int*>, ARGS will
8466 presently be {int*} -- but we need {int}. */
8469 }
8470 else
8471 {
8474 }
8476 /* If the template we're instantiating is incomplete, then clearly
8477 there's nothing we can do. */
8481 /* If we've recursively instantiated too many templates, stop. */
8485 /* Now we're really doing the instantiation. Mark the type as in
8486 the process of being defined. */
8489 /* We may be in the middle of deferred access check. Disable
8490 it now. */
8494 /* Use #pragma pack from the template context. */
8500 /* Set the input location to the most specialized template definition.
8501 This is needed if tsubsting causes an error. */
8523 {
8526 }
8531 /* We should never instantiate a nested class before its enclosing
8532 class; we need to look up the nested class by name before we can
8533 instantiate it, and that lookup should instantiate the enclosing
8534 class. */
8540 {
8541 tree pbase_binfo;
8542 tree pushed_scope;
8545 /* We must enter the scope containing the type, as that is where
8546 the accessibility of types named in dependent bases are
8547 looked up from. */
8550 /* Substitute into each of the bases to determine the actual
8551 basetypes. */
8553 {
8554 tree base;
8560 {
8561 expanded_bases =
8568 }
8571 {
8573 /* Extract the already-expanded base class. */
8575 else
8576 /* Substitute to figure out the base class. */
8578 NULL_TREE);
8586 }
8587 }
8589 /* The list is now in reverse order; correct that. */
8594 }
8595 /* Now call xref_basetypes to set up all the base-class
8596 information. */
8604 /* Now that our base classes are set up, enter the scope of the
8605 class, so that name lookups into base classes, etc. will work
8606 correctly. This is precisely analogous to what we do in
8607 begin_class_definition when defining an ordinary non-template
8608 class, except we also need to push the enclosing classes. */
8611 /* Now members are processed in the order of declaration. */
8614 {
8618 {
8620 {
8621 /* Build new CLASSTYPE_NESTED_UTDS. */
8623 tree newtag;
8629 /* If the member is a class template, then -- even after
8630 substitution -- there may be dependent types in the
8631 template argument list for the class. We increment
8632 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
8633 that function will assume that no types are dependent
8634 when outside of a template. */
8644 {
8648 /* Unfortunately, lookup_template_class sets
8649 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
8650 instantiation (i.e., for the type of a member
8651 template class nested within a template class.)
8652 This behavior is required for
8653 maybe_process_partial_specialization to work
8654 correctly, but is not accurate in this case;
8655 the TAG is not an instantiation of anything.
8656 (The corresponding TEMPLATE_DECL is an
8657 instantiation, but the TYPE is not.) */
8660 /* Now, we call pushtag to put this NEWTAG into the scope of
8661 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
8662 pushtag calling push_template_decl. We don't have to do
8663 this for enums because it will already have been done in
8664 tsubst_enum. */
8668 }
8669 }
8672 {
8673 /* Build new TYPE_METHODS. */
8674 tree r;
8683 /* Instantiate members marked with attribute used. */
8686 }
8687 else
8688 {
8689 /* Build new TYPE_FIELDS. */
8691 {
8692 tree condition =
8700 }
8702 {
8703 tree r;
8705 /* The file and line for this declaration, to
8706 assist in error message reporting. Since we
8707 called push_tinst_level above, we don't need to
8708 restore these. */
8717 {
8718 /* In [temp.inst]:
8720 [t]he initialization (and any associated
8721 side-effects) of a static data member does
8722 not occur unless the static data member is
8723 itself used in a way that requires the
8724 definition of the static data member to
8725 exist.
8727 Therefore, we do not substitute into the
8728 initialized for the static data member here. */
8729 finish_static_data_member_decl
8735 /* Instantiate members marked with attribute used. */
8738 }
8740 {
8741 /* Determine whether R has a valid type and can be
8742 completed later. If R is invalid, then it is
8743 replaced by error_mark_node so that it will not be
8744 added to TYPE_FIELDS. */
8750 {
8753 }
8754 }
8756 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
8757 such a thing will already have been added to the field
8758 list by tsubst_enum in finish_member_declaration in the
8759 CLASSTYPE_NESTED_UTDS case above. */
8763 {
8766 }
8767 }
8768 }
8769 }
8770 else
8771 {
8773 {
8774 /* Build new CLASSTYPE_FRIEND_CLASSES. */
8780 {
8781 /* template <class T> friend class C; */
8784 }
8786 {
8787 /* template <class T> friend class C::D; */
8793 }
8796 {
8797 /* This could be either
8799 friend class T::C;
8801 when dependent_type_p is false or
8803 template <class U> friend class T::C;
8805 otherwise. */
8808 /* Bump processing_template_decl for correct
8809 dependent_type_p calculation. */
8814 }
8817 {
8818 /* friend class C;
8820 where C hasn't been declared yet. Let's lookup name
8821 from namespace scope directly, bypassing any name that
8822 come from dependent base class. */
8825 /* The call to xref_tag_from_type does injection for friend
8826 classes. */
8828 friend_type =
8832 }
8834 /* friend class C<T>; */
8837 /* Otherwise it's
8839 friend class C;
8841 where C is already declared or
8843 friend class C<int>;
8845 We don't have to do anything in these cases. */
8848 /* Trick make_friend_class into realizing that the friend
8849 we're adding is a template, not an ordinary class. It's
8850 important that we use make_friend_class since it will
8851 perform some error-checking and output cross-reference
8852 information. */
8860 }
8861 else
8862 {
8863 /* Build new DECL_FRIENDLIST. */
8864 tree r;
8866 /* The file and line for this declaration, to
8867 assist in error message reporting. Since we
8868 called push_tinst_level above, we don't need to
8869 restore these. */
8873 {
8876 }
8881 {
8884 }
8885 }
8886 }
8887 }
8892 /* Set the file and line number information to whatever is given for
8893 the class itself. This puts error messages involving generated
8894 implicit functions at a predictable point, and the same point
8895 that would be used for non-template classes. */
8902 /* We don't instantiate default arguments for member functions. 14.7.1:
8904 The implicit instantiation of a class template specialization causes
8905 the implicit instantiation of the declarations, but not of the
8906 definitions or default arguments, of the class member functions,
8907 member classes, static data members and member templates.... */
8909 /* Some typedefs referenced from within the template code need to be access
8910 checked at template instantiation time, i.e now. These types were
8911 added to the template at parsing time. Let's get those and perform
8912 the access checks then. */
8921 /* The vtable for a template class can be emitted in any translation
8922 unit in which the class is instantiated. When there is no key
8923 method, however, finish_struct_1 will already have added TYPE to
8924 the keyed_classes list. */
8929 }
8931 /* Wrapper for instantiate_class_template_1. */
8933 tree
8935 {
8936 tree ret;
8941 }
8943 static tree
8945 {
8946 tree r;
8952 else
8953 {
8960 /* Preserve the raw-reference nature of T. */
8964 }
8966 }
8968 /* Given a function parameter pack TMPL_PARM and some function parameters
8969 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
8970 and set *SPEC_P to point at the next point in the list. */
8972 static tree
8974 {
8975 /* Collect all of the extra "packed" parameters into an
8976 argument pack. */
8977 tree parmvec;
8978 tree parmtypevec;
8989 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
8994 {
8997 }
8999 /* Build the argument packs. */
9006 }
9008 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9009 NONTYPE_ARGUMENT_PACK. */
9011 static tree
9013 {
9015 }
9017 /* Substitute ARGS into T, which is an pack expansion
9018 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
9019 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
9020 (if only a partial substitution could be performed) or
9021 ERROR_MARK_NODE if there was an error. */
9022 tree
9024 tree in_decl)
9025 {
9026 tree pattern;
9029 tree result;
9036 /* Determine the argument packs that will instantiate the parameter
9037 packs used in the expansion expression. While we're at it,
9038 compute the number of arguments to be expanded and make sure it
9039 is consistent. */
9042 {
9048 {
9051 else
9052 {
9053 /* We can't rely on local_specializations for a parameter
9054 name used later in a function declaration (such as in a
9055 late-specified return type). Even if it exists, it might
9056 have the wrong value for a recursive call. Just make a
9057 dummy decl, since it's only used for its type. */
9060 /* Partial instantiation of the parm_pack, we can't build
9061 up an argument pack yet. */
9063 else
9065 }
9066 }
9067 else
9068 {
9075 }
9082 /* This can only happen if we forget to expand an argument
9083 pack somewhere else. Just return an error, silently. */
9084 {
9088 }
9090 /* For clarity in the comments below let's use the
9091 representation 'argument_pack<elements>' to denote an
9092 argument pack and its elements.
9094 In the 'if' block below, we want to detect cases where
9095 ARG_PACK is argument_pack<PARM_PACK...>. I.e, we want to
9096 check if ARG_PACK is an argument pack which sole element is
9097 the expansion of PARM_PACK. That argument pack is typically
9098 created by template_parm_to_arg when passed a parameter
9099 pack. */
9103 {
9106 /* So we have an argument_pack<P...>. We want to test if P
9107 is actually PARM_PACK. We will not use cp_tree_equal to
9108 test P and PARM_PACK because during type fixup (by
9109 fixup_template_parm) P can be a pre-fixup version of a
9110 type and PARM_PACK be its post-fixup version.
9111 cp_tree_equal would consider them as different even
9112 though we would want to consider them compatible for our
9113 precise purpose here.
9115 Thus we are going to consider that P and PARM_PACK are
9116 compatible if they have the same DECL. */
9118 same DECL as parm_pack ... */
9122 /* ... or if ARG_PACK is a non-type parameter
9123 named by the same DECL as parm_pack ... */
9129 /* ... then the argument pack that the parameter maps to
9130 is just an expansion of the parameter itself, such as
9131 one would find in the implicit typedef of a class
9132 inside the class itself. Consider this parameter
9133 "unsubstituted", so that we will maintain the outer
9134 pack expansion. */
9136 }
9139 {
9143 /* It's all-or-nothing with incomplete argument packs. */
9153 {
9155 /* We got explicit args for some packs but not others;
9156 do nothing now and try again after deduction. */
9161 pattern);
9162 else
9165 pattern);
9167 }
9169 /* Keep track of the parameter packs and their corresponding
9170 argument packs. */
9173 }
9174 else
9175 /* We can't substitute for this parameter pack. */
9178 unsubstituted_packs);
9179 }
9181 /* We cannot expand this expansion expression, because we don't have
9182 all of the argument packs we need. Substitute into the pattern
9183 and return a PACK_EXPANSION_*. The caller will need to deal with
9184 that. */
9186 {
9187 tree new_pat;
9191 else
9194 }
9196 /* We could not find any argument packs that work. */
9201 {
9202 /* We're in a late-specified return type, so create our own local
9203 specializations table; the current table is either NULL or (in the
9204 case of recursive unification) might have bindings that we don't
9205 want to use or alter. */
9208 hash_local_specialization,
9209 eq_local_specializations,
9210 NULL);
9211 }
9213 /* For each argument in each argument pack, substitute into the
9214 pattern. */
9217 {
9218 /* For parameter pack, change the substitution of the parameter
9219 pack to the ith argument in its argument pack, then expand
9220 the pattern. */
9222 {
9226 {
9227 /* Select the Ith argument from the pack. */
9233 }
9234 else
9235 {
9241 {
9242 /* Select the Ith argument from the pack. */
9246 }
9248 /* Update the corresponding argument. */
9250 }
9251 }
9253 /* Substitute into the PATTERN with the altered arguments. */
9258 else
9262 /* When we have incomplete argument packs, the last "expanded"
9263 result is itself a pack expansion, which allows us
9264 to deduce more arguments. */
9269 {
9272 }
9273 }
9275 /* Update ARGS to restore the substitution from parameter packs to
9276 their argument packs. */
9278 {
9283 else
9284 {
9288 /* Update the corresponding argument. */
9292 else
9294 }
9295 }
9298 {
9301 }
9304 }
9306 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
9307 TMPL. We do this using DECL_PARM_INDEX, which should work even with
9308 parameter packs; all parms generated from a function parameter pack will
9309 have the same DECL_PARM_INDEX. */
9311 tree
9313 {
9315 tree patparm;
9318 {
9324 }
9325 else
9326 {
9331 }
9334 }
9336 /* Substitute ARGS into the vector or list of template arguments T. */
9338 static tree
9340 {
9352 {
9354 tree new_arg;
9359 {
9360 /* Substitute into an expansion expression. */
9364 /* Add to the expanded length adjustment the number of
9365 expanded arguments. We subtract one from this
9366 measurement, because the argument pack expression
9367 itself is already counted as 1 in
9368 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
9369 the argument pack is empty. */
9371 }
9373 {
9374 /* Substitute into each of the arguments. */
9380 new_arg,
9394 }
9395 }
9396 else
9405 }
9410 /* Make space for the expanded arguments coming from template
9411 argument packs. */
9413 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
9414 arguments for a member template.
9415 In that case each TREE_VEC in ORIG_T represents a level of template
9416 arguments, and ORIG_T won't carry any non defaulted argument count.
9417 It will rather be the nested TREE_VECs that will carry one.
9418 In other words, ORIG_T carries a non defaulted argument count only
9419 if it doesn't contain any nested TREE_VEC. */
9421 {
9425 }
9427 {
9431 {
9434 /* Now expand the template argument pack "in place". */
9437 }
9438 else
9439 {
9441 out++;
9442 }
9443 }
9446 }
9448 /* Return the result of substituting ARGS into the template parameters
9449 given by PARMS. If there are m levels of ARGS and m + n levels of
9450 PARMS, then the result will contain n levels of PARMS. For
9451 example, if PARMS is `template <class T> template <class U>
9452 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
9453 result will be `template <int*, double, class V>'. */
9455 static tree
9457 {
9461 /* When substituting into a template, we must set
9462 PROCESSING_TEMPLATE_DECL as the template parameters may be
9463 dependent if they are based on one-another, and the dependency
9464 predicates are short-circuit outside of templates. */
9471 {
9472 tree new_vec =
9477 {
9478 tree tuple;
9490 }
9496 }
9501 }
9503 /* Return the result of substituting ARGS into one template parameter
9504 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
9505 parameter and which TREE_PURPOSE is the default argument of the
9506 template parameter. */
9508 static tree
9510 {
9531 }
9533 /* Substitute the ARGS into the indicated aggregate (or enumeration)
9534 type T. If T is not an aggregate or enumeration type, it is
9535 handled as if by tsubst. IN_DECL is as for tsubst. If
9536 ENTERING_SCOPE is nonzero, T is the context for a template which
9537 we are presently tsubst'ing. Return the substituted value. */
9539 static tree
9541 tree args,
9542 tsubst_flags_t complain,
9543 tree in_decl,
9545 {
9550 {
9555 /* Else fall through. */
9559 {
9560 tree argvec;
9561 tree context;
9562 tree r;
9566 /* In "sizeof(X<I>)" we need to evaluate "I". */
9572 /* First, determine the context for the type we are looking
9573 up. */
9576 {
9579 /* If context is a nested class inside a class template,
9580 it may still need to be instantiated (c++/33959). */
9583 }
9585 /* Then, figure out what arguments are appropriate for the
9586 type we are trying to find. For example, given:
9588 template <class T> struct S;
9589 template <class T, class U> void f(T, U) { S<U> su; }
9591 and supposing that we are instantiating f<int, double>,
9592 then our ARGS will be {int, double}, but, when looking up
9593 S we only want {double}. */
9598 else
9599 {
9603 }
9609 }
9610 else
9611 /* This is not a template type, so there's nothing to do. */
9616 }
9617 }
9619 /* Substitute into the default argument ARG (a default argument for
9620 FN), which has the indicated TYPE. */
9622 tree
9624 {
9628 /* This can happen in invalid code. */
9632 /* This default argument came from a template. Instantiate the
9633 default argument here, not in tsubst. In the case of
9634 something like:
9636 template <class T>
9637 struct S {
9638 static T t();
9639 void f(T = t());
9640 };
9642 we must be careful to do name lookup in the scope of S<T>,
9643 rather than in the current class. */
9645 /* The "this" pointer is not valid in a default argument. */
9647 {
9652 }
9655 /* The default argument expression may cause implicitly defined
9656 member functions to be synthesized, which will result in garbage
9657 collection. We must treat this situation as if we were within
9658 the body of function so as to avoid collecting live data on the
9659 stack. */
9667 /* Restore the "this" pointer. */
9669 {
9672 }
9674 /* Make sure the default argument is reasonable. */
9680 }
9682 /* Substitute into all the default arguments for FN. */
9684 static void
9686 {
9687 tree arg;
9688 tree tmpl_args;
9692 /* If this function is not yet instantiated, we certainly don't need
9693 its default arguments. */
9696 /* Don't do this again for clones. */
9701 arg;
9707 }
9709 /* Substitute the ARGS into the T, which is a _DECL. Return the
9710 result of the substitution. Issue error and warning messages under
9711 control of COMPLAIN. */
9713 static tree
9715 {
9716 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
9717 location_t saved_loc;
9722 /* Set the filename and linenumber to improve error-reporting. */
9727 {
9729 {
9730 /* We can get here when processing a member function template,
9731 member class template, or template template parameter. */
9733 tree spec;
9734 tree tmpl_args;
9735 tree full_args;
9738 {
9739 /* Template template parameter is treated here. */
9752 complain);
9755 }
9757 /* We might already have an instance of this template.
9758 The ARGS are for the surrounding class type, so the
9759 full args contain the tsubst'd args for the context,
9760 plus the innermost args from the template decl. */
9764 /* Because this is a template, the arguments will still be
9765 dependent, even after substitution. If
9766 PROCESSING_TEMPLATE_DECL is not set, the dependency
9767 predicates will short-circuit. */
9775 /* If this is a default template template argument,
9776 tsubst might not have changed anything. */
9783 {
9786 }
9788 /* Make a new template decl. It will be similar to the
9789 original, but will record the current template arguments.
9790 We also create a new function declaration, which is just
9791 like the old one, but points to this new template, rather
9792 than the old one. */
9800 {
9801 tree new_type;
9813 }
9814 else
9815 {
9816 tree new_decl;
9828 }
9834 /* The template parameters for this new template are all the
9835 template parameters for the old template, except the
9836 outermost level of parameters. */
9839 complain);
9845 /* Record this non-type partial instantiation. */
9849 }
9853 {
9854 tree ctx;
9857 tree gen_tmpl;
9858 tree type;
9863 /* Nobody should be tsubst'ing into non-template functions. */
9867 {
9868 tree spec;
9871 /* If T is not dependent, just return it. We have to
9872 increment PROCESSING_TEMPLATE_DECL because
9873 value_dependent_expression_p assumes that nothing is
9874 dependent when PROCESSING_TEMPLATE_DECL is zero. */
9881 /* Calculate the most general template of which R is a
9882 specialization, and the complete set of arguments used to
9883 specialize R. */
9886 (DECL_TEMPLATE_RESULT
9892 /* Check to see if we already have this specialization. */
9897 {
9900 }
9902 /* We can see more levels of arguments than parameters if
9903 there was a specialization of a member template, like
9904 this:
9906 template <class T> struct S { template <class U> void f(); }
9907 template <> template <class U> void S<int>::f(U);
9909 Here, we'll be substituting into the specialization,
9910 because that's where we can find the code we actually
9911 want to generate, but we'll have enough arguments for
9912 the most general template.
9914 We also deal with the peculiar case:
9916 template <class T> struct S {
9917 template <class U> friend void f();
9918 };
9919 template <class U> void f() {}
9920 template S<int>;
9921 template void f<double>();
9923 Here, the ARGS for the instantiation of will be {int,
9924 double}. But, we only need as many ARGS as there are
9925 levels of template parameters in CODE_PATTERN. We are
9926 careful not to get fooled into reducing the ARGS in
9927 situations like:
9929 template <class T> struct S { template <class U> void f(U); }
9930 template <class T> template <> void S<T>::f(int) {}
9932 which we can spot because the pattern will be a
9933 specialization in this case. */
9935 parms_depth =
9940 }
9941 else
9942 {
9943 /* This special case arises when we have something like this:
9945 template <class T> struct S {
9946 friend void f<int>(int, double);
9947 };
9949 Here, the DECL_TI_TEMPLATE for the friend declaration
9950 will be an IDENTIFIER_NODE. We are being called from
9951 tsubst_friend_function, and we want only to create a
9952 new decl (R) with appropriate types so that we can call
9953 determine_specialization. */
9955 }
9958 {
9961 else
9965 }
9966 else
9967 {
9970 }
9975 /* We do NOT check for matching decls pushed separately at this
9976 point, as they may not represent instantiations of this
9977 template, and in any case are considered separate under the
9978 discrete model. */
9982 /* Clear out the mangled name and RTL for the instantiation. */
9985 /* Leave DECL_INITIAL set on deleted instantiations. */
9991 /* Type-conversion operator. Reconstruct the name, in
9992 case it's the name of one of the template's parameters. */
10002 /* If this is an instantiation of a function with internal
10003 linkage, we already know what object file linkage will be
10004 assigned to the instantiation. */
10013 /* We'll re-clone as appropriate in instantiate_template. */
10016 /* If we aren't complaining now, return on error before we register
10017 the specialization so that we'll complain eventually. */
10023 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
10024 this in the special friend case mentioned above where
10025 GEN_TMPL is NULL. */
10027 {
10033 /* We're not supposed to instantiate default arguments
10034 until they are called, for a template. But, for a
10035 declaration like:
10037 template <class T> void f ()
10038 { extern void g(int i = T()); }
10040 we should do the substitution when the template is
10041 instantiated. We handle the member function case in
10042 instantiate_class_template since the default arguments
10043 might refer to other members of the class. */
10048 }
10049 else
10052 /* Copy the list of befriending classes. */
10056 {
10060 in_decl);
10061 }
10064 {
10068 /* If this is an instantiation of a member template, clone it.
10069 If it isn't, that'll be handled by
10070 clone_constructors_and_destructors. */
10073 }
10084 /* Possibly limit visibility based on template args. */
10087 {
10091 }
10099 }
10103 {
10111 {
10112 /* If there is a local specialization that isn't a
10113 parameter pack, it means that we're doing a "simple"
10114 substitution from inside tsubst_pack_expansion. Just
10115 return the local specialization (which will be a single
10116 parm). */
10123 /* Expand the TYPE_PACK_EXPANSION that provides the types for
10124 the parameters in this function parameter pack. */
10128 {
10131 /* Zero-length parameter packs are boring. Just substitute
10132 into the chain. */
10136 }
10137 else
10138 {
10139 /* All we did was update the type. Make a note of that. */
10142 }
10143 }
10145 /* Loop through all of the parameter's we'll build. When T is
10146 a function parameter pack, LEN is the number of expanded
10147 types in EXPANDED_TYPES; otherwise, LEN is 1. */
10150 {
10157 /* We're on the Ith parameter of the function parameter
10158 pack. */
10159 {
10160 /* An argument of a function parameter pack is not a parameter
10161 pack. */
10164 /* Get the Ith type. */
10168 /* Rename the parameter to include the index. */
10171 }
10173 /* We're dealing with a normal parameter. */
10181 {
10184 else
10187 }
10197 /* Keep track of the first new parameter we
10198 generate. That's what will be returned to the
10199 caller. */
10203 /* Build a proper chain of parameters when substituting
10204 into a function parameter pack. */
10207 }
10213 /* FIRST_R contains the start of the chain we've built. */
10215 }
10219 {
10220 tree type;
10229 /* DECL_INITIAL gives the number of bits in a bit-field. */
10234 /* We don't have to set DECL_CONTEXT here; it is set by
10235 finish_member_declaration. */
10242 }
10246 /* We reach here only for member using decls. */
10248 {
10249 r = do_class_using_decl
10254 else
10255 {
10258 }
10259 }
10260 else
10261 {
10264 }
10269 {
10272 tree spec;
10274 tree ctx;
10280 {
10281 /* If this is the canonical decl, we don't have to
10282 mess with instantiations, and often we can't (for
10283 typename, template type parms and such). Note that
10284 TYPE_NAME is not correct for the above test if
10285 we've copied the type for a typedef. */
10291 }
10293 /* Check to see if we already have the specialization we
10294 need. */
10297 {
10298 /* T is a static data member or namespace-scope entity.
10299 We have to substitute into namespace-scope variables
10300 (even though such entities are never templates) because
10301 of cases like:
10303 template <class T> void f() { extern T t; }
10305 where the entity referenced is not known until
10306 instantiation time. */
10310 {
10312 complain,
10314 /* If CTX is unchanged, then T is in fact the
10315 specialization we want. That situation occurs when
10316 referencing a static data member within in its own
10317 class. We can use pointer equality, rather than
10318 same_type_p, because DECL_CONTEXT is always
10319 canonical. */
10322 }
10325 {
10331 }
10332 }
10333 else
10334 {
10335 /* A local variable. */
10337 /* Subsequent calls to pushdecl will fill this in. */
10340 }
10341 /* If we already have the specialization we need, there is
10342 nothing more to do. */
10344 {
10347 }
10349 /* Create a new node for the specialization we need. */
10352 {
10355 else
10360 }
10362 {
10363 /* Even if the original location is out of scope, the
10364 newly substituted one is not. */
10371 {
10372 /* It may seem that this case cannot occur, since:
10374 typedef void f();
10375 void g() { f x; }
10377 declares a function, not a variable. However:
10379 typedef void f();
10380 template <typename T> void g() { T t; }
10381 template void g<f>();
10383 is an attempt to declare a variable with function
10384 type. */
10386 /* R is not yet sufficiently initialized, so we
10387 just use its name. */
10390 }
10392 /* Wait until cp_finish_decl to set this again, to handle
10393 circular dependency (template/instantiate6.C). */
10398 {
10403 {
10406 }
10408 }
10409 }
10415 /* Clear out the mangled name and RTL for the instantiation. */
10419 /* The initializer must not be expanded until it is required;
10420 see [temp.inst]. */
10426 {
10427 /* Possibly limit visibility based on template args. */
10430 {
10434 }
10436 }
10439 {
10440 /* A static data member declaration is always marked
10441 external when it is declared in-class, even if an
10442 initializer is present. We mimic the non-template
10443 processing here. */
10449 }
10451 {
10452 /* We're substituting this var in a decltype outside of its
10453 scope, such as for a lambda return type. Don't add it to
10454 local_specializations, do perform auto deduction. */
10457 {
10458 tree init
10464 }
10465 }
10466 else
10475 /* Preserve a typedef that names a type. */
10477 {
10480 }
10483 }
10488 }
10489 #undef RETURN
10491 out:
10492 /* Restore the file and line information. */
10496 }
10498 /* Substitute into the ARG_TYPES of a function type. */
10500 static tree
10502 tree args,
10503 tsubst_flags_t complain,
10504 tree in_decl)
10505 {
10506 tree remaining_arg_types;
10510 tree default_arg;
10521 {
10522 /* For a pack expansion, perform substitution on the
10523 entire expression. Later on, we'll handle the arguments
10524 one-by-one. */
10529 /* So that we'll spin through the parameters, one by one. */
10531 else
10532 {
10533 /* We only partially substituted into the parameter
10534 pack. Our type is TYPE_PACK_EXPANSION. */
10537 }
10538 }
10551 {
10553 {
10557 }
10559 }
10561 /* Do array-to-pointer, function-to-pointer conversion, and ignore
10562 top-level qualifiers as required. */
10565 /* We do not substitute into default arguments here. The standard
10566 mandates that they be instantiated only when needed, which is
10567 done in build_over_call. */
10571 {
10572 /* We've instantiated a template before its default arguments
10573 have been parsed. This can happen for a nested template
10574 class, and is not an error unless we require the default
10575 argument in a call of this function. */
10576 remaining_arg_types =
10579 remaining_arg_types);
10580 }
10581 else
10582 remaining_arg_types =
10584 }
10587 }
10589 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
10590 *not* handle the exception-specification for FNTYPE, because the
10591 initial substitution of explicitly provided template parameters
10592 during argument deduction forbids substitution into the
10593 exception-specification:
10595 [temp.deduct]
10597 All references in the function type of the function template to the
10598 corresponding template parameters are replaced by the specified tem-
10599 plate argument values. If a substitution in a template parameter or
10600 in the function type of the function template results in an invalid
10601 type, type deduction fails. [Note: The equivalent substitution in
10602 exception specifications is done only when the function is instanti-
10603 ated, at which point a program is ill-formed if the substitution
10604 results in an invalid type.] */
10606 static tree
10608 tree args,
10609 tsubst_flags_t complain,
10610 tree in_decl)
10611 {
10612 tree return_type;
10613 tree arg_types;
10614 tree fntype;
10616 /* The TYPE_CONTEXT is not used for function/method types. */
10619 /* Substitute the return type. */
10623 /* The standard does not presently indicate that creation of a
10624 function type with an invalid return type is a deduction failure.
10625 However, that is clearly analogous to creating an array of "void"
10626 or a reference to a reference. This is core issue #486. */
10629 {
10631 {
10634 else
10636 }
10638 }
10640 /* Substitute the argument types. */
10646 /* Construct a new type node and return it. */
10648 {
10651 }
10652 else
10653 {
10656 {
10657 /* [temp.deduct]
10659 Type deduction may fail for any of the following
10660 reasons:
10662 -- Attempting to create "pointer to member of T" when T
10663 is not a class type. */
10666 r);
10668 }
10672 }
10676 }
10678 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
10679 ARGS into that specification, and return the substituted
10680 specification. If there is no specification, return NULL_TREE. */
10682 static tree
10684 tree args,
10685 tsubst_flags_t complain,
10686 tree in_decl,
10688 {
10689 tree specs;
10690 tree new_specs;
10695 {
10696 /* A noexcept-specifier. */
10701 {
10702 /* Defer instantiation of noexcept-specifiers to avoid
10703 excessive instantiations (c++/49107). */
10706 {
10707 /* We already partially instantiated this member template,
10708 so combine the new args with the old. */
10713 }
10714 else
10715 {
10718 }
10719 }
10720 else
10721 new_specs = tsubst_copy_and_build
10725 }
10727 {
10730 else
10732 {
10733 tree spec;
10738 {
10739 /* Expand the pack expansion type. */
10742 in_decl);
10748 else
10749 {
10750 /* We're substituting into a member template, so
10751 we got a TYPE_PACK_EXPANSION back. Add that
10752 expansion and move on. */
10756 expanded_specs,
10757 complain);
10760 }
10761 }
10764 {
10767 else
10772 complain);
10773 }
10776 }
10777 }
10779 }
10781 /* Take the tree structure T and replace template parameters used
10782 therein with the argument vector ARGS. IN_DECL is an associated
10783 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
10784 Issue error and warning messages under control of COMPLAIN. Note
10785 that we must be relatively non-tolerant of extensions here, in
10786 order to preserve conformance; if we allow substitutions that
10787 should not be allowed, we may allow argument deductions that should
10788 not succeed, and therefore report ambiguous overload situations
10789 where there are none. In theory, we could allow the substitution,
10790 but indicate that it should have failed, and allow our caller to
10791 make sure that the right thing happens, but we don't try to do this
10792 yet.
10794 This function is used for dealing with types, decls and the like;
10795 for expressions, use tsubst_expr or tsubst_copy. */
10797 tree
10799 {
10822 else
10827 /* Reuse typedefs. We need to do this to handle dependent attributes,
10828 such as attribute aligned. */
10831 {
10837 {
10841 }
10846 else
10847 /* The typedef is from a non-template context. */
10851 {
10853 r = cp_build_qualified_type_real
10857 }
10858 /* Else we must be instantiating the typedef, so fall through. */
10859 }
10872 {
10898 {
10904 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
10905 needed. */
10911 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
10912 with TREE_SIDE_EFFECTS that indicates this is not an integral
10913 constant expression. */
10916 {
10919 }
10922 }
10928 {
10941 {
10945 /* See through ARGUMENT_PACK_SELECT arguments. */
10947 }
10952 {
10954 /* If ARG is an argument pack, we don't actually want to
10955 perform a substitution here, because substitutions
10956 for argument packs are only done
10957 element-by-element. We can get to this point when
10958 substituting the type of a non-type template
10959 parameter pack, when that type actually contains
10960 template parameter packs from an outer template, e.g.,
10962 template<typename... Types> struct A {
10963 template<Types... Values> struct B { };
10964 }; */
10968 {
10974 return cp_build_qualified_type_real
10976 }
10978 {
10979 /* We are processing a type constructed from a
10980 template template parameter. */
10986 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
10987 are resolving nested-types in the signature of a
10988 member function templates. Otherwise ARG is a
10989 TEMPLATE_DECL and is the real template to be
10990 instantiated. */
10998 complain);
10999 return cp_build_qualified_type_real
11001 }
11002 else
11003 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
11005 }
11008 /* This can happen during the attempted tsubst'ing in
11009 unify. This means that we don't yet have any information
11010 about the template parameter in question. */
11013 /* If we get here, we must have been looking at a parm for a
11014 more deeply nested template. Make a new version of this
11015 template parameter, but with a lower level. */
11017 {
11022 {
11024 r = cp_build_qualified_type_real
11028 }
11029 else
11030 {
11041 /* We have reduced the level of the template
11042 template parameter, but not the levels of its
11043 template parameters, so canonical_type_parameter
11044 will not be able to find the canonical template
11045 template parameter for this level. Thus, we
11046 require structural equality checking to compare
11047 TEMPLATE_TEMPLATE_PARMs. */
11051 else
11055 {
11063 }
11064 }
11073 }
11076 }
11079 {
11087 {
11091 }
11094 {
11098 }
11101 {
11105 }
11111 }
11114 /* We should never be tsubsting a binfo. */
11118 /* A vector of template arguments. */
11124 {
11128 /* [temp.deduct]
11130 Type deduction may fail for any of the following
11131 reasons:
11133 -- Attempting to create a pointer to reference type.
11134 -- Attempting to create a reference to a reference type or
11135 a reference to void.
11137 Core issue 106 says that creating a reference to a reference
11138 during instantiation is no longer a cause for failure. We
11139 only enforce this check in strict C++98 mode. */
11143 {
11146 /* We keep track of the last time we issued this error
11147 message to avoid spewing a ton of messages during a
11148 single bad template instantiation. */
11151 {
11156 else
11159 }
11162 }
11164 {
11168 }
11170 /* In C++0x, during template argument substitution, when there is an
11171 attempt to create a reference to a reference type, reference
11172 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
11174 "If a template-argument for a template-parameter T names a type
11175 that is a reference to a type A, an attempt to create the type
11176 'lvalue reference to cv T' creates the type 'lvalue reference to
11177 A,' while an attempt to create the type type rvalue reference to
11178 cv T' creates the type T"
11179 */
11180 r = cp_build_reference_type
11183 else
11188 /* Will this ever be needed for TYPE_..._TO values? */
11192 }
11194 {
11197 {
11198 /* [temp.deduct]
11200 Type deduction may fail for any of the following
11201 reasons:
11203 -- Attempting to create "pointer to member of T" when T
11204 is not a class type. */
11208 }
11210 {
11214 }
11216 {
11220 }
11223 {
11224 /* The type of the implicit object parameter gets its
11225 cv-qualifiers from the FUNCTION_TYPE. */
11226 tree memptr;
11230 complain);
11231 }
11232 else
11235 complain);
11236 }
11239 {
11240 tree fntype;
11241 tree specs;
11246 /* Substitute the exception specification. */
11254 }
11256 {
11261 /* As an optimization, we avoid regenerating the array type if
11262 it will obviously be the same as T. */
11266 /* These checks should match the ones in grokdeclarator.
11268 [temp.deduct]
11270 The deduction may fail for any of the following reasons:
11272 -- Attempting to create an array with an element type that
11273 is void, a function type, or a reference type, or [DR337]
11274 an abstract class type. */
11278 {
11282 }
11284 {
11287 type);
11289 }
11294 {
11297 }
11300 }
11303 {
11313 {
11317 }
11319 {
11320 /* Normally, make_typename_type does not require that the CTX
11321 have complete type in order to allow things like:
11323 template <class T> struct S { typename S<T>::X Y; };
11325 But, such constructs have already been resolved by this
11326 point, so here CTX really should have complete type, unless
11327 it's a partial instantiation. */
11330 {
11334 }
11335 }
11342 {
11345 }
11348 {
11350 {
11354 else
11356 }
11358 {
11362 else
11364 }
11365 }
11367 return cp_build_qualified_type_real
11369 }
11372 {
11384 }
11387 {
11388 tree type;
11404 complain);
11405 }
11408 {
11409 tree type;
11427 else
11428 type = finish_decltype_type
11433 complain);
11434 }
11437 {
11441 }
11445 {
11447 tree packed_out =
11449 args,
11450 complain,
11451 in_decl);
11454 /* For template nontype argument packs, also substitute into
11455 the type. */
11460 }
11475 /* We should use one of the expression tsubsts for these codes. */
11481 }
11482 }
11484 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
11485 type of the expression on the left-hand side of the "." or "->"
11486 operator. */
11488 static tree
11491 {
11492 tree name;
11493 tree qualifying_scope;
11494 tree fns;
11495 tree optype;
11499 /* A baselink indicates a function from a base class. Both the
11500 BASELINK_ACCESS_BINFO and the base class referenced may
11501 indicate bases of the template class, rather than the
11502 instantiated class. In addition, lookups that were not
11503 ambiguous before may be ambiguous now. Therefore, we perform
11504 the lookup again. */
11511 {
11518 }
11526 /* If lookup found a single function, mark it as used at this
11527 point. (If it lookup found multiple functions the one selected
11528 later by overload resolution will be marked as used at that
11529 point.) */
11535 /* Add back the template arguments, if present. */
11540 template_args);
11541 /* Update the conversion operator type. */
11547 qualifying_scope,
11548 object_type);
11549 }
11551 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
11552 true if the qualified-id will be a postfix-expression in-and-of
11553 itself; false if more of the postfix-expression follows the
11554 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
11555 of "&". */
11557 static tree
11561 {
11562 tree expr;
11563 tree scope;
11564 tree name;
11566 tree template_args;
11570 /* Figure out what name to look up. */
11573 {
11580 }
11581 else
11582 {
11585 }
11587 /* Substitute into the qualifying scope. When there are no ARGS, we
11588 are just trying to simplify a non-dependent expression. In that
11589 case the qualifying scope may be dependent, and, in any case,
11590 substituting will not help. */
11593 {
11596 }
11597 else
11601 {
11606 }
11609 {
11611 {
11612 /* A BIT_NOT_EXPR is used to represent a destructor. */
11614 {
11618 }
11619 else
11622 }
11623 else
11627 {
11629 {
11633 }
11635 }
11636 }
11639 {
11641 scope);
11642 /* Remember that there was a reference to this entity. */
11644 }
11647 {
11653 }
11662 {
11663 expr = (adjust_result_of_qualified_name_lookup
11665 expr = (finish_qualified_id_expr
11669 }
11671 /* Expressions do not generally have reference type. */
11673 /* However, if we're about to form a pointer-to-member, we just
11674 want the referenced member referenced. */
11679 }
11681 /* Like tsubst, but deals with expressions. This function just replaces
11682 template parms; to finish processing the resultant expression, use
11683 tsubst_expr. */
11685 static tree
11687 {
11689 tree r;
11697 {
11702 {
11703 tree c;
11704 /* This can happen for a parameter name used later in a function
11705 declaration (such as in a late-specified return type). Just
11706 make a dummy decl, since it's only used for its type. */
11708 /* We copy T because want to tsubst the PARM_DECL only,
11709 not the following PARM_DECLs that are chained to T. */
11712 /* Give it the template pattern as its context; its true context
11713 hasn't been instantiated yet and this is good enough for
11714 mangling. */
11716 }
11724 {
11725 tree enum_type;
11726 tree v;
11730 /* There is no need to substitute into namespace-scope
11731 enumerators. */
11734 /* If ARGS is NULL, then T is known to be non-dependent. */
11738 /* Unfortunately, we cannot just call lookup_name here.
11739 Consider:
11741 template <int I> int f() {
11742 enum E { a = I };
11743 struct S { void g() { E e = a; } };
11744 };
11746 When we instantiate f<7>::S::g(), say, lookup_name is not
11747 clever enough to find f<7>::a. */
11748 enum_type
11758 /* We didn't find the name. That should never happen; if
11759 name-lookup found it during preliminary parsing, we
11760 should find it again here during instantiation. */
11762 }
11767 {
11768 tree ctx;
11773 {
11776 {
11780 }
11782 }
11783 }
11796 /* An OVERLOAD will always be a non-dependent overload set; an
11797 overload set from function scope will just be represented with an
11798 IDENTIFIER_NODE, and from class scope with a BASELINK. */
11813 {
11814 /* Template template argument like the following example need
11815 special treatment:
11817 template <template <class> class TT> struct C {};
11818 template <class T> struct D {
11819 template <class U> struct E {};
11820 C<E> c; // #1
11821 };
11822 D<int> d; // #2
11824 We are processing the template argument `E' in #1 for
11825 the template instantiation #2. Originally, `E' is a
11826 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
11827 have to substitute this with one having context `D<int>'. */
11831 }
11832 else
11833 /* Ordinary template template argument. */
11842 return build1
11848 {
11850 tree expanded;
11855 /* We only want to compute the number of arguments. */
11870 {
11877 else
11880 }
11881 else
11883 }
11884 /* Fall through */
11899 return build1
11904 {
11905 tree object;
11906 tree name;
11911 {
11915 }
11918 {
11928 }
11933 in_decl);
11934 else
11937 }
11975 return build_nt
11988 return build_nt
11995 {
12003 }
12008 {
12009 r = build_nt
12015 }
12018 {
12019 r = build_nt
12025 }
12028 {
12029 r = build_nt
12035 }
12038 {
12039 /* Substituted template arguments */
12048 }
12051 {
12071 }
12096 {
12099 }
12100 else
12104 /* This is handled by tsubst_copy_and_build. */
12109 in_decl),
12113 /* We shouldn't have built any of these during initial template
12114 generation. Instead, they should be built during instantiation
12115 in response to the saved STMT_IS_FULL_EXPR_P setting. */
12119 r = build2
12139 {
12140 /* Instantiate any typedefs in the type. */
12145 }
12148 /* These can sometimes show up in a partial instantiation, but never
12149 involve template parms. */
12154 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
12157 }
12158 }
12160 /* Like tsubst_copy, but specifically for OpenMP clauses. */
12162 static tree
12164 tree in_decl)
12165 {
12169 {
12175 {
12178 {
12184 }
12185 /* FALLTHRU */
12209 }
12210 }
12213 }
12215 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
12217 static tree
12219 tree in_decl)
12220 {
12221 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
12246 #undef RECUR
12247 }
12249 /* Substitute one OMP_FOR iterator. */
12251 static void
12256 {
12257 #define RECUR(NODE) \
12258 tsubst_expr ((NODE), args, complain, in_decl, \
12259 integral_constant_expression_p)
12268 {
12275 }
12279 {
12285 complain);
12286 else
12293 }
12296 {
12297 tree c;
12299 {
12310 }
12312 {
12317 {
12320 }
12321 }
12322 }
12328 else
12332 {
12343 {
12350 }
12351 else
12357 {
12363 }
12367 {
12374 }
12375 else
12381 }
12387 #undef RECUR
12388 }
12390 /* Like tsubst_copy for expressions, etc. but also does semantic
12391 processing. */
12393 static tree
12396 {
12397 #define RECUR(NODE) \
12398 tsubst_expr ((NODE), args, complain, in_decl, \
12399 integral_constant_expression_p)
12412 {
12414 {
12415 tree_stmt_iterator i;
12419 }
12434 else
12443 {
12445 tree init;
12451 {
12454 tree decl;
12462 else
12464 }
12465 else
12466 {
12470 {
12471 /* By marking the declaration as instantiated, we avoid
12472 trying to instantiate it. Since instantiate_decl can't
12473 handle local variables, and since we've already done
12474 all that needs to be done, that's the right thing to
12475 do. */
12480 /* Anonymous aggregates are a special case. */
12482 else
12483 {
12488 {
12489 /* For __PRETTY_FUNCTION__ we have to adjust the
12490 initializer. */
12494 }
12495 else
12496 {
12500 {
12501 /* If we had an initializer but it
12502 instantiated to nothing,
12503 value-initialize the object. This will
12504 only occur when the initializer was a
12505 pack expansion where the parameter packs
12506 used in that expansion were of length
12507 zero. */
12509 complain);
12512 }
12513 else
12515 }
12518 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
12521 }
12522 }
12523 }
12525 /* A DECL_EXPR can also be used as an expression, in the condition
12526 clause of an if/for/while construct. */
12528 }
12543 {
12553 }
12580 {
12584 }
12592 else
12600 else
12627 {
12629 tree label;
12634 }
12640 /* Computed goto's must be tsubst'd into. On the other hand,
12641 non-computed gotos must not be; the identifier in question
12642 will have no binding. */
12644 else
12650 tmp = finish_asm_stmt
12657 {
12662 }
12667 {
12672 }
12673 else
12674 {
12679 else
12686 else
12692 else
12694 }
12698 {
12702 {
12704 /* Prevent instantiate_decl from trying to instantiate
12705 this variable. We've already done all that needs to be
12706 done. */
12709 }
12714 }
12722 {
12723 tree condition =
12725 args,
12732 }
12753 {
12768 integral_constant_expression_p);
12777 {
12781 }
12782 else
12783 {
12791 }
12805 }
12837 {
12842 {
12845 }
12850 }
12851 else
12852 {
12859 {
12862 }
12865 {
12870 {
12873 }
12877 }
12878 else
12879 {
12883 }
12885 }
12901 integral_constant_expression_p);
12902 }
12905 #undef RECUR
12906 }
12908 /* T is a postfix-expression that is not being used in a function
12909 call. Return the substituted version of T. */
12911 static tree
12913 tsubst_flags_t complain,
12914 tree in_decl)
12915 {
12919 else
12925 }
12927 /* Like tsubst but deals with expressions and performs semantic
12928 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
12930 tree
12932 tree args,
12933 tsubst_flags_t complain,
12934 tree in_decl,
12937 {
12938 #define RECUR(NODE) \
12939 tsubst_copy_and_build (NODE, args, complain, in_decl, \
12941 integral_constant_expression_p)
12943 tree op1;
12949 {
12952 /* Fall through. */
12954 {
12955 tree decl;
12956 cp_id_kind idk;
12961 {
12964 }
12966 /* Look up the name. */
12969 /* By convention, expressions use ERROR_MARK_NODE to indicate
12970 failure, not NULL_TREE. */
12976 integral_constant_expression_p,
12984 input_location);
12990 }
12993 {
12994 tree object;
13002 {
13005 }
13006 else
13013 else
13015 }
13018 {
13022 {
13023 /* A type conversion to reference type will be enclosed in
13024 such an indirect ref, but the substitution of the cast
13025 will have also added such an indirect ref. */
13028 }
13029 else
13032 }
13035 return build_nop
13044 {
13045 tree type;
13046 tree op;
13051 {
13056 }
13061 {
13074 }
13075 }
13093 complain);
13103 else
13105 in_decl);
13139 return build_x_binary_op
13143 ? ERROR_MARK
13147 ? ERROR_MARK
13150 complain);
13163 /* Fall through */
13168 {
13169 /* When there are no ARGS, we are trying to evaluate a
13170 non-dependent expression from the parser. Trying to do
13171 the substitutions may not work. */
13174 }
13175 else
13176 {
13184 }
13188 else
13193 {
13203 }
13217 {
13218 tree r = build_x_modify_expr
13222 complain);
13223 /* TREE_NO_WARNING must be set if either the expression was
13224 parenthesized or it uses an operator such as >>= rather
13225 than plain assignment. In the former case, it was already
13226 set and must be copied. In the latter case,
13227 build_x_modify_expr sets it and it must not be reset
13228 here. */
13232 }
13237 /* Remember that there was a reference to this entity. */
13243 {
13248 tree ret;
13252 else
13253 {
13257 }
13259 /* If there was an initializer in the original tree, but it
13260 instantiated to an empty list, then we should pass a
13261 non-NULL empty vector to tell build_new that it was an
13262 empty initializer() rather than no initializer. This can
13263 only happen when the initializer is a pack expansion whose
13264 parameter packs are of length zero. */
13267 else
13268 {
13272 else
13273 {
13276 }
13277 }
13284 complain);
13292 }
13295 return delete_sanity
13300 complain);
13305 complain);
13308 {
13309 tree function;
13314 tree ret;
13317 /* When we parsed the expression, we determined whether or
13318 not Koenig lookup should be performed. */
13321 {
13326 }
13328 {
13329 /* Do nothing; calling tsubst_copy_and_build on an identifier
13330 would incorrectly perform unqualified lookup again.
13332 Note that we can also have an IDENTIFIER_NODE if the earlier
13333 unqualified lookup found a member function; in that case
13334 koenig_p will be false and we do want to do the lookup
13335 again to find the instantiated member function.
13337 FIXME but doing that causes c++/15272, so we need to stop
13338 using IDENTIFIER_NODE in that situation. */
13340 }
13341 else
13342 {
13344 {
13350 }
13351 else
13355 in_decl,
13357 integral_constant_expression_p);
13361 }
13366 {
13372 else
13373 {
13374 /* Expand the pack expansion and push each entry onto
13375 CALL_ARGS. */
13378 {
13383 {
13388 }
13389 }
13390 else
13391 {
13392 /* A partial substitution. Add one entry. */
13394 }
13395 }
13396 }
13398 /* We do not perform argument-dependent lookup if normal
13399 lookup finds a non-function, in accordance with the
13400 expected resolution of DR 218. */
13403 /* If lookup found a member function, the Koenig lookup is
13404 not appropriate, even if an unqualified-name was used
13405 to denote the function. */
13408 /* Only do this when substitution turns a dependent call
13409 into a non-dependent call. */
13413 tf_none);
13417 {
13419 {
13420 /* For backwards compatibility and good diagnostics, try
13421 the unqualified lookup again if we aren't in SFINAE
13422 context. */
13423 tree unq = (tsubst_copy_and_build
13425 integral_constant_expression_p));
13427 {
13434 "%qD was not declared in this scope, "
13435 "and no declarations were found by "
13436 "argument-dependent lookup at the point "
13439 {
13441 "declarations in dependent base %qT are "
13447 else
13451 }
13452 else
13456 }
13457 }
13459 {
13463 }
13464 }
13466 /* Remember that there was a reference to this entity. */
13473 {
13488 complain);
13489 else
13490 ret = (build_new_method_call
13495 complain));
13496 }
13497 else
13500 koenig_p,
13501 complain);
13506 }
13509 return build_x_conditional_expr
13513 complain);
13516 return finish_pseudo_destructor_expr
13522 {
13530 {
13531 /* We have pack expansions, so expand those and
13532 create a new list out of it. */
13535 tree chain;
13538 /* Expand the argument expressions. */
13546 /* Build the rest of the list. */
13551 /* Determine the number of arguments. */
13553 {
13556 }
13559 else
13560 {
13561 /* Since we only performed a partial substitution into
13562 the argument pack, we only return a single list
13563 node. */
13570 }
13572 /* Convert the argument vectors into a TREE_LIST */
13575 {
13576 /* Grab the Ith values. */
13577 i--;
13580 value
13584 /* Build the list (backwards). */
13586 }
13589 }
13605 }
13608 {
13609 tree object;
13610 tree object_type;
13611 tree member;
13615 /* Remember that there was a reference to this entity. */
13625 else
13631 {
13633 {
13638 {
13641 }
13643 {
13647 }
13648 }
13649 }
13652 {
13653 tree tmpl;
13654 tree args;
13656 /* Lookup the template functions now that we know what the
13657 scope is. */
13664 {
13667 args);
13668 member = (adjust_result_of_qualified_name_lookup
13670 object_type));
13671 }
13672 else
13673 {
13675 input_location);
13677 }
13678 }
13682 {
13684 {
13688 else
13691 }
13693 }
13699 complain);
13700 }
13703 return build_throw
13707 {
13715 tree r;
13720 /* digest_init will do the wrong thing if we let it. */
13724 /* We do not want to process the index of aggregate
13725 initializers as they are identifier nodes which will be
13726 looked up by digest_init. */
13732 {
13737 {
13738 /* Substitute into the pack expansion. */
13740 in_decl);
13744 ;
13746 /* Just move the argument into place. */
13748 else
13749 {
13750 /* Update the length of the final CONSTRUCTOR
13751 arguments vector, and note that we will need to
13752 copy.*/
13755 }
13756 }
13757 else
13759 }
13762 {
13767 {
13769 {
13774 }
13775 else
13777 }
13778 }
13788 }
13791 {
13794 {
13797 }
13798 else
13799 {
13802 }
13803 }
13808 /* Fall through */
13811 {
13815 /* If the original type was a reference, we'll be wrapped in
13816 the appropriate INDIRECT_REF. */
13819 }
13829 {
13838 }
13841 {
13847 integral_constant_expression_p);
13851 /* If the resulting list of expression statement is empty,
13852 fold it further into void_zero_node. */
13857 }
13861 /* As in finish_id_expression, we resolve enumeration constants
13862 to their underlying values. */
13864 {
13867 }
13871 {
13892 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
13894 /* Now that we know visibility, instantiate the type so we have a
13895 declaration of the op() for later calls to lambda_function. */
13903 }
13906 /* We can get here for a constant initializer of non-dependent type.
13907 FIXME stop folding in cp_parser_initializer_clause. */
13909 {
13913 }
13916 /* Handle Objective-C++ constructs, if appropriate. */
13917 {
13918 tree subst
13923 }
13925 }
13927 #undef RECUR
13928 }
13930 /* Verify that the instantiated ARGS are valid. For type arguments,
13931 make sure that the type's linkage is ok. For non-type arguments,
13932 make sure they are constants if they are integral or enumerations.
13933 Emit an error under control of COMPLAIN, and return TRUE on error. */
13935 static bool
13937 {
13939 {
13949 }
13951 {
13952 /* [basic.link]: A name with no linkage (notably, the name
13953 of a class or enumeration declared in a local scope)
13954 shall not be used to declare an entity with linkage.
13955 This implies that names with no linkage cannot be used as
13956 template arguments
13958 DR 757 relaxes this restriction for C++0x. */
13963 {
13964 /* DR 488 makes use of a type with no linkage cause
13965 type deduction to fail. */
13967 {
13970 else
13973 }
13975 }
13976 /* In order to avoid all sorts of complications, we do not
13977 allow variably-modified types as template arguments. */
13979 {
13983 }
13984 }
13985 /* A non-type argument of integral or enumerated type must be a
13986 constant. */
13990 {
13994 }
13996 }
13998 static bool
14000 {
14005 {
14008 }
14012 }
14014 /* In C++0x, it's possible to have a function template whose type depends
14015 on itself recursively. This is most obvious with decltype, but can also
14016 occur with enumeration scope (c++/48969). So we need to catch infinite
14017 recursion and reject the substitution at deduction time; this function
14018 will return error_mark_node for any repeated substitution.
14020 This also catches excessive recursion such as when f<N> depends on
14021 f<N-1> across all integers, and returns error_mark_node for all the
14022 substitutions back up to the initial one.
14024 This is, of course, not reentrant. */
14026 static tree
14028 {
14035 tree tinst;
14036 tree r;
14043 {
14047 }
14057 {
14060 /* Reset once we're all the way out. */
14062 }
14065 /* We can't free this if a pending_template entry or last_error_tinst_level
14066 is pointing at it. */
14071 }
14073 /* Instantiate the indicated variable or function template TMPL with
14074 the template arguments in TARG_PTR. */
14076 static tree
14078 {
14080 tree fndecl;
14081 tree gen_tmpl;
14082 tree spec;
14083 HOST_WIDE_INT saved_processing_template_decl;
14090 /* If this function is a clone, handle it specially. */
14092 {
14093 tree spec;
14094 tree clone;
14096 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
14097 DECL_CLONED_FUNCTION. */
14103 /* Look for the clone. */
14107 /* We should always have found the clone by now. */
14110 }
14112 /* Check to see if we already have this specialization. */
14115 /* The TMPL is a partial instantiation. To get a full set of
14116 arguments we must add the arguments used to perform the
14117 partial instantiation. */
14119 targ_ptr);
14121 /* It would be nice to avoid hashing here and then again in tsubst_decl,
14122 but it doesn't seem to be on the hot path. */
14134 complain))
14137 /* We are building a FUNCTION_DECL, during which the access of its
14138 parameters and return types have to be checked. However this
14139 FUNCTION_DECL which is the desired context for access checking
14140 is not built yet. We solve this chicken-and-egg problem by
14141 deferring all checks until we have the FUNCTION_DECL. */
14144 /* Although PROCESSING_TEMPLATE_DECL may be true at this point
14145 (because, for example, we have encountered a non-dependent
14146 function call in the body of a template function and must now
14147 determine which of several overloaded functions will be called),
14148 within the instantiation itself we are not processing a
14149 template. */
14152 /* Substitute template parameters to obtain the specialization. */
14159 /* Now we know the specialization, compute access previously
14160 deferred. */
14163 /* Some typedefs referenced from within the template code need to be access
14164 checked at template instantiation time, i.e now. These types were
14165 added to the template at parsing time. Let's get those and perfom
14166 the acces checks then. */
14172 /* The DECL_TI_TEMPLATE should always be the immediate parent
14173 template, not the most general template. */
14176 /* If we've just instantiated the main entry point for a function,
14177 instantiate all the alternate entry points as well. We do this
14178 by cloning the instantiation of the main entry point, not by
14179 instantiating the template clones. */
14184 }
14186 /* Wrapper for instantiate_template_1. */
14188 tree
14190 {
14191 tree ret;
14196 }
14198 /* We're going to do deduction substitution on the type of TMPL, a function
14199 template. In C++11 mode, push into that access scope. In C++03 mode,
14200 disable access checking. */
14202 static void
14204 {
14206 {
14209 /* Preserve processing_template_decl across push_to_top_level. */
14212 }
14213 else
14215 }
14217 /* And pop back out. */
14219 static void
14221 {
14224 else
14226 }
14228 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
14229 NARGS elements of the arguments that are being used when calling
14230 it. TARGS is a vector into which the deduced template arguments
14231 are placed.
14233 Return zero for success, 2 for an incomplete match that doesn't resolve
14234 all the types, and 1 for complete failure. An error message will be
14235 printed only for an incomplete match.
14237 If FN is a conversion operator, or we are trying to produce a specific
14238 specialization, RETURN_TYPE is the return type desired.
14240 The EXPLICIT_TARGS are explicit template arguments provided via a
14241 template-id.
14243 The parameter STRICT is one of:
14245 DEDUCE_CALL:
14246 We are deducing arguments for a function call, as in
14247 [temp.deduct.call].
14249 DEDUCE_CONV:
14250 We are deducing arguments for a conversion function, as in
14251 [temp.deduct.conv].
14253 DEDUCE_EXACT:
14254 We are deducing arguments when doing an explicit instantiation
14255 as in [temp.explicit], when determining an explicit specialization
14256 as in [temp.expl.spec], or when taking the address of a function
14257 template, as in [temp.deduct.funcaddr]. */
14259 int
14261 tree explicit_targs,
14262 tree targs,
14265 tree return_type,
14266 unification_kind_t strict,
14269 {
14270 tree parms;
14271 tree fntype;
14279 {
14280 /* [temp.deduct]
14282 The specified template arguments must match the template
14283 parameters in kind (i.e., type, nontype, template), and there
14284 must not be more arguments than there are parameters;
14285 otherwise type deduction fails.
14287 Nontype arguments must match the types of the corresponding
14288 nontype template parameters, or must be convertible to the
14289 types of the corresponding nontype parameters as specified in
14290 _temp.arg.nontype_, otherwise type deduction fails.
14292 All references in the function type of the function template
14293 to the corresponding template parameters are replaced by the
14294 specified template argument values. If a substitution in a
14295 template parameter or in the function type of the function
14296 template results in an invalid type, type deduction fails. */
14299 tree converted_args;
14305 converted_args
14307 (explain_p
14308 ? tf_warning_or_error
14315 /* Substitute the explicit args into the function type. This is
14316 necessary so that, for instance, explicitly declared function
14317 arguments can match null pointed constants. If we were given
14318 an incomplete set of explicit args, we must not do semantic
14319 processing during substitution as we could create partial
14320 instantiations. */
14322 {
14326 /* Dig out the actual parm. */
14329 {
14332 }
14334 {
14337 }
14340 {
14342 tree targ;
14345 /* Mark the argument pack as "incomplete". We could
14346 still deduce more arguments during unification.
14347 We remove this mark in type_unification_real. */
14350 {
14354 }
14356 /* We have some incomplete argument packs. */
14358 }
14359 }
14362 /* Any substitution is guaranteed to be incomplete if there
14363 are incomplete argument packs, because we can still deduce
14364 more arguments. */
14366 else
14371 (explain_p
14372 ? tf_warning_or_error
14379 /* Place the explicitly specified arguments in TARGS. */
14382 }
14384 /* Never do unification on the 'this' parameter. */
14388 {
14397 }
14399 /* We allow incomplete unification without an error message here
14400 because the standard doesn't seem to explicitly prohibit it. Our
14401 callers must be ready to deal with unification failures in any
14402 event. */
14407 /* Now that we have bindings for all of the template arguments,
14408 ensure that the arguments deduced for the template template
14409 parameters have compatible template parameter lists. We cannot
14410 check this property before we have deduced all template
14411 arguments, because the template parameter types of a template
14412 template parameter might depend on prior template parameters
14413 deduced after the template template parameter. The following
14414 ill-formed example illustrates this issue:
14416 template<typename T, template<T> class C> void f(C<5>, T);
14418 template<int N> struct X {};
14420 void g() {
14421 f(X<5>(), 5l); // error: template argument deduction fails
14422 }
14424 The template parameter list of 'C' depends on the template type
14425 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
14426 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
14427 time that we deduce 'C'. */
14429 && !template_template_parm_bindings_ok_p
14434 /* All is well so far. Now, check:
14436 [temp.deduct]
14438 When all template arguments have been deduced, all uses of
14439 template parameters in nondeduced contexts are replaced with
14440 the corresponding deduced argument values. If the
14441 substitution results in an invalid type, as described above,
14442 type deduction fails. */
14443 {
14445 (explain_p
14446 ? tf_warning_or_error
14451 /* If we're looking for an exact match, check that what we got
14452 is indeed an exact match. It might not be if some template
14453 parameters are used in non-deduced contexts. */
14455 {
14458 tree sarg
14466 }
14467 }
14470 }
14472 /* Adjust types before performing type deduction, as described in
14473 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
14474 sections are symmetric. PARM is the type of a function parameter
14475 or the return type of the conversion function. ARG is the type of
14476 the argument passed to the call, or the type of the value
14477 initialized with the result of the conversion function.
14478 ARG_EXPR is the original argument expression, which may be null. */
14480 static int
14484 tree arg_expr)
14485 {
14489 {
14494 {
14495 /* Swap PARM and ARG throughout the remainder of this
14496 function; the handling is precisely symmetric since PARM
14497 will initialize ARG rather than vice versa. */
14502 }
14505 /* Core issue #873: Do the DR606 thing (see below) for these cases,
14506 too, but here handle it by stripping the reference from PARM
14507 rather than by adding it to ARG. */
14515 /* Nothing else to do in this case. */
14520 }
14523 {
14524 /* [temp.deduct.call]
14526 If P is not a reference type:
14528 --If A is an array type, the pointer type produced by the
14529 array-to-pointer standard conversion (_conv.array_) is
14530 used in place of A for type deduction; otherwise,
14532 --If A is a function type, the pointer type produced by
14533 the function-to-pointer standard conversion
14534 (_conv.func_) is used in place of A for type deduction;
14535 otherwise,
14537 --If A is a cv-qualified type, the top level
14538 cv-qualifiers of A's type are ignored for type
14539 deduction. */
14544 else
14546 }
14548 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
14549 of the form T&&, where T is a template parameter, and the argument
14550 is an lvalue, T is deduced as A& */
14556 /* try_one_overload doesn't provide an arg_expr, but
14557 functions are always lvalues. */
14561 /* [temp.deduct.call]
14563 If P is a cv-qualified type, the top level cv-qualifiers
14564 of P's type are ignored for type deduction. If P is a
14565 reference type, the type referred to by P is used for
14566 type deduction. */
14569 {
14572 }
14574 /* DR 322. For conversion deduction, remove a reference type on parm
14575 too (which has been swapped into ARG). */
14580 }
14582 /* Most parms like fn_type_unification.
14584 If SUBR is 1, we're being called recursively (to unify the
14585 arguments of a function or method parameter of a function
14586 template). */
14588 static int
14590 tree targs,
14591 tree xparms,
14595 unification_kind_t strict,
14598 {
14604 tree parms;
14613 /* Reset the number of non-defaulted template arguments contained
14614 in TARGS. */
14618 {
14634 }
14636 again:
14644 {
14649 /* For a function parameter pack that occurs at the end of the
14650 parameter-declaration-list, the type A of each remaining
14651 argument of the call is compared with the type P of the
14652 declarator-id of the function parameter pack. */
14658 /* For a function parameter pack that does not occur at the
14659 end of the parameter-declaration-list, the type of the
14660 parameter pack is a non-deduced context. */
14670 /* We can't deduce anything from this, but we might get all the
14671 template args from other function args. */
14674 /* Conversions will be performed on a function argument that
14675 corresponds with a function parameter that contains only
14676 non-deducible template parameters and explicitly specified
14677 template parameters. */
14679 {
14680 tree type;
14684 else
14691 flags))
14696 else
14698 }
14701 {
14704 {
14705 /* [temp.deduct.type]
14707 A template-argument can be deduced from a pointer to
14708 function or pointer to member function argument if
14709 the set of overloaded functions does not contain
14710 function templates and at most one of a set of
14711 overloaded functions provides a unique match. */
14717 }
14722 }
14724 {
14729 arg_expr);
14734 /* If unification failed, the recursive call will have updated
14735 UI appropriately. */
14737 }
14738 }
14744 {
14745 /* Unify the remaining arguments with the pack expansion type. */
14746 tree argvec;
14749 /* Allocate a TREE_VEC and copy in all of the arguments */
14754 /* Copy the parameter into parmvec. */
14760 /* Advance to the end of the list of parameters. */
14762 }
14764 /* Fail if we've reached the end of the parm list, and more args
14765 are present, and the parm list isn't variadic. */
14768 /* Fail if parms are left and they don't have default values. */
14771 {
14775 {
14776 count++;
14778 }
14780 }
14783 {
14784 /* Check to see if we need another pass before we start clearing
14785 ARGUMENT_PACK_INCOMPLETE_P. */
14787 {
14795 /* If this is an undeduced nontype parameter that depends on
14796 a type parameter, try another pass; its type may have been
14797 deduced from a later argument than the one from which
14798 this parameter can be deduced. */
14803 }
14806 {
14810 /* Clear the "incomplete" flags on all argument packs now so that
14811 substituting them into later default arguments works. */
14813 {
14816 }
14822 /* Core issue #226 (C++0x) [temp.deduct]:
14824 If a template argument has not been deduced, its
14825 default template argument, if any, is used.
14827 When we are in C++98 mode, TREE_PURPOSE will either
14828 be NULL_TREE or ERROR_MARK_NODE, so we do not need
14829 to explicitly check cxx_dialect here. */
14831 {
14836 (explain_p
14837 ? tf_warning_or_error
14842 else
14843 {
14845 /* The position of the first default template argument,
14846 is also the number of non-defaulted arguments in TARGS.
14847 Record that. */
14851 }
14852 }
14854 /* If the type parameter is a parameter pack, then it will
14855 be deduced to an empty parameter pack. */
14857 {
14858 tree arg;
14861 {
14865 }
14866 else
14873 }
14876 }
14877 }
14878 #ifdef ENABLE_CHECKING
14881 #endif
14884 }
14886 /* Subroutine of type_unification_real. Args are like the variables
14887 at the call site. ARG is an overloaded function (or template-id);
14888 we try deducing template args from each of the overloads, and if
14889 only one succeeds, we go with that. Modifies TARGS and returns
14890 true on success. */
14892 static bool
14894 tree targs,
14895 tree parm,
14896 tree arg,
14897 unification_kind_t strict,
14900 {
14907 {
14910 }
14911 else
14915 /* Handle `&x' where `x' is some static or non-static member
14916 function name. */
14922 /* Strip baselink information. */
14927 {
14928 /* If we got some explicit template args, we need to plug them into
14929 the affected templates before we try to unify, in case the
14930 explicit args will completely resolve the templates in question. */
14937 {
14948 {
14953 {
14956 }
14957 }
14961 }
14962 /* If no templates (or more than one) are fully resolved by the
14963 explicit arguments, this template-id is a non-deduced context; it
14964 could still be OK if we deduce all template arguments for the
14965 enclosing call through other arguments. */
14968 }
14971 /* If ARG is, for example, "(0, &f)" then its type will be unknown
14972 -- but the deduction does not succeed because the expression is
14973 not just the function on its own. */
14975 else
14981 {
14984 }
14986 /* [temp.deduct.type] A template-argument can be deduced from a pointer
14987 to function or pointer to member function argument if the set of
14988 overloaded functions does not contain function templates and at most
14989 one of a set of overloaded functions provides a unique match.
14991 So if we found multiple possibilities, we return success but don't
14992 deduce anything. */
14995 {
15000 }
15005 }
15007 /* Core DR 115: In contexts where deduction is done and fails, or in
15008 contexts where deduction is not done, if a template argument list is
15009 specified and it, along with any default template arguments, identifies
15010 a single function template specialization, then the template-id is an
15011 lvalue for the function template specialization. */
15013 tree
15015 {
15028 {
15031 }
15033 {
15036 }
15038 {
15041 }
15044 {
15048 /* If we got some explicit template args, we need to plug them into
15049 the affected templates before we try to unify, in case the
15050 explicit args will completely resolve the templates in question. */
15058 {
15069 {
15072 {
15075 }
15077 {
15080 }
15081 }
15083 }
15085 {
15093 {
15094 tree base
15097 }
15101 }
15103 /* There were no good options and at least one bad one, so let the
15104 user know what the problem is. */
15106 }
15108 }
15110 /* Subroutine of resolve_overloaded_unification; does deduction for a single
15111 overload. Fills TARGS with any deduced arguments, or error_mark_node if
15112 different overloads deduce different arguments for a given parm.
15113 ADDR_P is true if the expression for which deduction is being
15114 performed was of the form "& fn" rather than simply "fn".
15116 Returns 1 on success. */
15118 static int
15120 tree orig_targs,
15121 tree targs,
15122 tree parm,
15123 tree arg,
15124 unification_kind_t strict,
15128 {
15130 tree tempargs;
15133 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15134 to function or pointer to member function argument if the set of
15135 overloaded functions does not contain function templates and at most
15136 one of a set of overloaded functions provides a unique match.
15138 So if this is a template, just return success. */
15150 /* We don't copy orig_targs for this because if we have already deduced
15151 some template args from previous args, unify would complain when we
15152 try to deduce a template parameter for the same argument, even though
15153 there isn't really a conflict. */
15160 /* First make sure we didn't deduce anything that conflicts with
15161 explicitly specified args. */
15163 {
15170 /* Since we're unifying against ourselves, we will fill in
15171 template args used in the function parm list with our own
15172 template parms. Discard them. */
15176 }
15179 {
15184 }
15187 }
15189 /* PARM is a template class (perhaps with unbound template
15190 parameters). ARG is a fully instantiated type. If ARG can be
15191 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
15192 TARGS are as for unify. */
15194 static tree
15197 {
15198 tree copy_of_targs;
15205 /* We need to make a new template argument vector for the call to
15206 unify. If we used TARGS, we'd clutter it up with the result of
15207 the attempted unification, even if this class didn't work out.
15208 We also don't want to commit ourselves to all the unifications
15209 we've already done, since unification is supposed to be done on
15210 an argument-by-argument basis. In other words, consider the
15211 following pathological case:
15213 template <int I, int J, int K>
15214 struct S {};
15216 template <int I, int J>
15217 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
15219 template <int I, int J, int K>
15220 void f(S<I, J, K>, S<I, I, I>);
15222 void g() {
15223 S<0, 0, 0> s0;
15224 S<0, 1, 2> s2;
15226 f(s0, s2);
15227 }
15229 Now, by the time we consider the unification involving `s2', we
15230 already know that we must have `f<0, 0, 0>'. But, even though
15231 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
15232 because there are two ways to unify base classes of S<0, 1, 2>
15233 with S<I, I, I>. If we kept the already deduced knowledge, we
15234 would reject the possibility I=1. */
15237 /* If unification failed, we're done. */
15243 }
15245 /* Given a template type PARM and a class type ARG, find the unique
15246 base type in ARG that is an instance of PARM. We do not examine
15247 ARG itself; only its base-classes. If there is not exactly one
15248 appropriate base class, return NULL_TREE. PARM may be the type of
15249 a partial specialization, as well as a plain template type. Used
15250 by unify. */
15252 static enum template_base_result
15255 {
15257 tree binfo;
15263 {
15264 /* The type could not be completed. */
15267 }
15269 /* Walk in inheritance graph order. The search order is not
15270 important, and this avoids multiple walks of virtual bases. */
15272 {
15277 {
15278 /* If there is more than one satisfactory baseclass, then:
15280 [temp.deduct.call]
15282 If they yield more than one possible deduced A, the type
15283 deduction fails.
15285 applies. */
15287 {
15290 }
15293 }
15294 }
15298 }
15300 /* Returns the level of DECL, which declares a template parameter. */
15302 static int
15304 {
15306 {
15316 }
15318 }
15320 /* Decide whether ARG can be unified with PARM, considering only the
15321 cv-qualifiers of each type, given STRICT as documented for unify.
15322 Returns nonzero iff the unification is OK on that basis. */
15324 static int
15326 {
15332 {
15333 /* Although a CVR qualifier is ignored when being applied to a
15334 substituted template parameter ([8.3.2]/1 for example), that
15335 does not allow us to unify "const T" with "int&" because both
15336 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
15337 It is ok when we're allowing additional CV qualifiers
15338 at the outer level [14.8.2.1]/3,1st bullet. */
15348 }
15359 }
15361 /* Determines the LEVEL and INDEX for the template parameter PARM. */
15362 void
15364 {
15368 {
15371 }
15372 else
15373 {
15376 }
15377 }
15379 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
15380 do { \
15381 if (unify (TP, TA, P, A, S, EP)) \
15382 return 1; \
15383 } while (0);
15385 /* Unifies the remaining arguments in PACKED_ARGS with the pack
15386 expansion at the end of PACKED_PARMS. Returns 0 if the type
15387 deduction succeeds, 1 otherwise. STRICT is the same as in
15388 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
15389 call argument list. We'll need to adjust the arguments to make them
15390 types. SUBR tells us if this is from a recursive call to
15391 type_unification_real. */
15392 static int
15396 {
15397 tree parm
15404 /* Determine the parameter packs we will be deducing from the
15405 pattern, and record their current deductions. */
15408 {
15412 /* Determine the index and level of this parameter pack. */
15415 /* Keep track of the parameter packs and their corresponding
15416 argument packs. */
15419 }
15421 /* Loop through all of the arguments that have not yet been
15422 unified and unify each with the pattern. */
15424 {
15427 /* For each parameter pack, clear out the deduced value so that
15428 we can deduce it again. */
15430 {
15435 }
15437 /* Unify the pattern with the current argument. */
15438 {
15444 {
15447 /* This mirrors what we do in type_unification_real. */
15449 {
15451 sub_strict = (UNIFY_ALLOW_OUTER_LEVEL
15452 | UNIFY_ALLOW_MORE_CV_QUAL
15466 }
15469 {
15472 {
15473 /* [temp.deduct.type] A template-argument can be
15474 deduced from a pointer to function or pointer
15475 to member function argument if the set of
15476 overloaded functions does not contain function
15477 templates and at most one of a set of
15478 overloaded functions provides a unique
15479 match. */
15487 }
15493 }
15498 arg_strict |=
15501 }
15503 /* For deduction from an init-list we need the actual list. */
15507 explain_p);
15508 }
15510 unified:
15511 /* For each parameter pack, collect the deduced value. */
15513 {
15519 }
15520 }
15522 /* Verify that the results of unification with the parameter packs
15523 produce results consistent with what we've seen before, and make
15524 the deduced argument packs available. */
15526 {
15533 /* By default keep the original deduced argument pack.
15534 If necessary, more specific code is going to update the
15535 resulting deduced argument later down in this function. */
15539 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
15540 actually deduce anything. */
15548 {
15549 /* Prepend the explicit arguments onto NEW_ARGS. */
15555 /* Copy the explicit arguments. */
15560 /* Copy the deduced arguments. */
15564 }
15567 {
15568 tree result;
15569 /* Build the deduced *_ARGUMENT_PACK. */
15571 {
15576 }
15577 else
15582 /* Note the deduced argument packs for this parameter
15583 pack. */
15585 }
15589 {
15590 /* We only had the explicitly-provided arguments before, but
15591 now we have a complete set of arguments. */
15597 }
15598 else
15599 {
15605 /* Inconsistent unification of this parameter pack. */
15607 bad_old_arg,
15608 bad_new_arg);
15609 }
15610 }
15613 }
15615 /* Deduce the value of template parameters. TPARMS is the (innermost)
15616 set of template parameters to a template. TARGS is the bindings
15617 for those template parameters, as determined thus far; TARGS may
15618 include template arguments for outer levels of template parameters
15619 as well. PARM is a parameter to a template function, or a
15620 subcomponent of that parameter; ARG is the corresponding argument.
15621 This function attempts to match PARM with ARG in a manner
15622 consistent with the existing assignments in TARGS. If more values
15623 are deduced, then TARGS is updated.
15625 Returns 0 if the type deduction succeeds, 1 otherwise. The
15626 parameter STRICT is a bitwise or of the following flags:
15628 UNIFY_ALLOW_NONE:
15629 Require an exact match between PARM and ARG.
15630 UNIFY_ALLOW_MORE_CV_QUAL:
15631 Allow the deduced ARG to be more cv-qualified (by qualification
15632 conversion) than ARG.
15633 UNIFY_ALLOW_LESS_CV_QUAL:
15634 Allow the deduced ARG to be less cv-qualified than ARG.
15635 UNIFY_ALLOW_DERIVED:
15636 Allow the deduced ARG to be a template base class of ARG,
15637 or a pointer to a template base class of the type pointed to by
15638 ARG.
15639 UNIFY_ALLOW_INTEGER:
15640 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
15641 case for more information.
15642 UNIFY_ALLOW_OUTER_LEVEL:
15643 This is the outermost level of a deduction. Used to determine validity
15644 of qualification conversions. A valid qualification conversion must
15645 have const qualified pointers leading up to the inner type which
15646 requires additional CV quals, except at the outer level, where const
15647 is not required [conv.qual]. It would be normal to set this flag in
15648 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
15649 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
15650 This is the outermost level of a deduction, and PARM can be more CV
15651 qualified at this point.
15652 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
15653 This is the outermost level of a deduction, and PARM can be less CV
15654 qualified at this point. */
15656 static int
15659 {
15661 tree targ;
15662 tree tparm;
15665 /* I don't think this will do the right thing with respect to types.
15666 But the only case I've seen it in so far has been array bounds, where
15667 signedness is the only information lost, and I think that will be
15668 okay. */
15676 /* We can't deduce anything from this, but we might get all the
15677 template args from other function args. */
15680 /* If PARM uses template parameters, then we can't bail out here,
15681 even if ARG == PARM, since we won't record unifications for the
15682 template parameters. We might need them if we're trying to
15683 figure out which of two things is more specialized. */
15687 /* Handle init lists early, so the rest of the function can assume
15688 we're dealing with a type. */
15690 {
15695 /* Replace T with std::initializer_list<T> for deduction. */
15701 /* We can only deduce from an initializer list argument if the
15702 parameter is std::initializer_list; otherwise this is a
15703 non-deduced context. */
15709 {
15716 {
15718 /* It should only be possible to get here for a call. */
15720 elt_strict |= maybe_adjust_types_for_deduction
15723 }
15726 explain_p);
15727 }
15729 /* If the std::initializer_list<T> deduction worked, replace the
15730 deduced A with std::initializer_list<A>. */
15732 {
15737 }
15739 }
15741 /* Immediately reject some pairs that won't unify because of
15742 cv-qualification mismatches. */
15745 /* It is the elements of the array which hold the cv quals of an array
15746 type, and the elements might be template type parms. We'll check
15747 when we recurse. */
15749 /* We check the cv-qualifiers when unifying with template type
15750 parameters below. We want to allow ARG `const T' to unify with
15751 PARM `T' for example, when computing which of two templates
15752 is more specialized, for example. */
15766 {
15770 /* In a type which contains a nested-name-specifier, template
15771 argument values cannot be deduced for template parameters used
15772 within the nested-name-specifier. */
15784 /* The PARM is not one we're trying to unify. Just check
15785 to see if it matches ARG. */
15786 {
15790 else
15792 }
15797 /* Check for mixed types and values. */
15805 {
15806 /* ARG must be constructed from a template class or a template
15807 template parameter. */
15812 {
15816 tree parm_parms
15817 = DECL_INNERMOST_TEMPLATE_PARMS
15822 /* The resolution to DR150 makes clear that default
15823 arguments for an N-argument may not be used to bind T
15824 to a template template parameter with fewer than N
15825 parameters. It is not safe to permit the binding of
15826 default arguments as an extension, as that may change
15827 the meaning of a conforming program. Consider:
15829 struct Dense { static const unsigned int dim = 1; };
15831 template <template <typename> class View,
15832 typename Block>
15833 void operator+(float, View<Block> const&);
15835 template <typename Block,
15836 unsigned int Dim = Block::dim>
15837 struct Lvalue_proxy { operator float() const; };
15839 void
15840 test_1d (void) {
15841 Lvalue_proxy<Dense> p;
15842 float b;
15843 b + p;
15844 }
15846 Here, if Lvalue_proxy is permitted to bind to View, then
15847 the global operator+ will be used; if they are not, the
15848 Lvalue_proxy will be converted to float. */
15850 full_argvec,
15852 (explain_p
15853 ? tf_warning_or_error
15860 /* Deduce arguments T, i from TT<T> or TT<i>.
15861 We check each element of PARMVEC and ARGVEC individually
15862 rather than the whole TREE_VEC since they can have
15863 different number of elements. */
15870 /* Check if the parameters end in a pack, making them
15871 variadic. */
15881 {
15886 }
15891 UNIFY_ALLOW_NONE,
15895 }
15898 /* Fall through to deduce template name. */
15899 }
15903 {
15904 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
15906 /* Simple cases: Value already set, does match or doesn't. */
15911 }
15912 else
15913 {
15914 /* If PARM is `const T' and ARG is only `int', we don't have
15915 a match unless we are allowing additional qualification.
15916 If ARG is `const int' and PARM is just `T' that's OK;
15917 that binds `const int' to `T'. */
15922 /* Consider the case where ARG is `const volatile int' and
15923 PARM is `const T'. Then, T should be `volatile int'. */
15924 arg = cp_build_qualified_type_real
15929 /* Simple cases: Value already set, does match or doesn't. */
15935 /* Make sure that ARG is not a variable-sized array. (Note
15936 that were talking about variable-sized arrays (like
15937 `int[n]'), rather than arrays of unknown size (like
15938 `int[]').) We'll get very confused by such a type since
15939 the bound of the array is not constant, and therefore
15940 not mangleable. Besides, such types are not allowed in
15941 ISO C++, so we can do as we please here. We do allow
15942 them for 'auto' deduction, since that isn't ABI-exposed. */
15946 /* Strip typedefs as in convert_template_argument. */
15948 }
15950 /* If ARG is a parameter pack or an expansion, we cannot unify
15951 against it unless PARM is also a parameter pack. */
15956 /* If the argument deduction results is a METHOD_TYPE,
15957 then there is a problem.
15958 METHOD_TYPE doesn't map to any real C++ type the result of
15959 the deduction can not be of that type. */
15973 {
15974 /* The PARM is not one we're trying to unify. Just check
15975 to see if it matches ARG. */
15981 }
15987 {
15992 }
15994 /* [temp.deduct.type] If, in the declaration of a function template
15995 with a non-type template-parameter, the non-type
15996 template-parameter is used in an expression in the function
15997 parameter-list and, if the corresponding template-argument is
15998 deduced, the template-argument type shall match the type of the
15999 template-parameter exactly, except that a template-argument
16000 deduced from an array bound may be of any integral type.
16001 The non-type parameter might use already deduced type parameters. */
16004 /* Template-parameter dependent expression. Just accept it for now.
16005 It will later be processed in convert_template_argument. */
16006 ;
16012 /* Convert the ARG to the type of PARM; the deduced non-type
16013 template argument must exactly match the types of the
16014 corresponding parameter. */
16017 /* We haven't deduced the type of this parameter yet. Try again
16018 later. */
16020 else
16023 /* If ARG is a parameter pack or an expansion, we cannot unify
16024 against it unless PARM is also a parameter pack. */
16033 {
16034 /* A pointer-to-member constant can be unified only with
16035 another constant. */
16039 /* Just unify the class member. It would be useless (and possibly
16040 wrong, depending on the strict flags) to unify also
16041 PTRMEM_CST_CLASS, because we want to be sure that both parm and
16042 arg refer to the same variable, even if through different
16043 classes. For instance:
16045 struct A { int x; };
16046 struct B : A { };
16048 Unification of &A::x and &B::x must succeed. */
16051 }
16054 {
16058 /* [temp.deduct.call]
16060 A can be another pointer or pointer to member type that can
16061 be converted to the deduced A via a qualification
16062 conversion (_conv.qual_).
16064 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
16065 This will allow for additional cv-qualification of the
16066 pointed-to types if appropriate. */
16069 /* The derived-to-base conversion only persists through one
16070 level of pointers. */
16075 }
16090 {
16091 tree parm_max;
16092 tree arg_max;
16096 /* Our representation of array types uses "N - 1" as the
16097 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
16098 not an integer constant. We cannot unify arbitrarily
16099 complex expressions, so we eliminate the MINUS_EXPRs
16100 here. */
16104 {
16107 }
16111 {
16112 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
16113 trying to unify the type of a variable with the type
16114 of a template parameter. For example:
16116 template <unsigned int N>
16117 void f (char (&) [N]);
16118 int g();
16119 void h(int i) {
16120 char a[g(i)];
16121 f(a);
16122 }
16124 Here, the type of the ARG will be "int [g(i)]", and
16125 may be a SAVE_EXPR, etc. */
16129 }
16131 /* If only one of the bounds used a MINUS_EXPR, compensate
16132 by adding one to the other bound. */
16135 integer_type_node,
16136 parm_max,
16137 integer_one_node);
16140 integer_type_node,
16141 arg_max,
16142 integer_one_node);
16146 }
16160 /* We have already checked cv-qualification at the top of the
16161 function. */
16165 /* As far as unification is concerned, this wins. Later checks
16166 will invalidate it if necessary. */
16169 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
16170 /* Type INTEGER_CST can come from ordinary constant template args. */
16182 {
16195 }
16203 {
16211 }
16214 {
16218 {
16219 /* First, we try to unify the PARM and ARG directly. */
16224 {
16225 /* Fallback to the special case allowed in
16226 [temp.deduct.call]:
16228 If P is a class, and P has the form
16229 template-id, then A can be a derived class of
16230 the deduced A. Likewise, if P is a pointer to
16231 a class of the form template-id, A can be a
16232 pointer to a derived class pointed to by the
16233 deduced A. */
16240 }
16241 }
16245 /* Perhaps PARM is something like S<U> and ARG is S<int>.
16246 Then, we should unify `int' and `U'. */
16248 else
16249 /* There's no chance of unification succeeding. */
16254 }
16261 {
16264 tree a;
16270 /* CV qualifications for methods can never be deduced, they must
16271 match exactly. We need to check them explicitly here,
16272 because type_unification_real treats them as any other
16273 cv-qualified parameter. */
16275 && (!check_cv_quals_for_unify
16295 }
16298 /* Unify a pointer to member with a pointer to member function, which
16299 deduces the type of the member as a function type. */
16301 {
16302 tree method_type;
16303 tree fntype;
16305 /* Check top-level cv qualifiers */
16313 /* Determine the type of the function we are unifying against. */
16315 fntype =
16319 /* Extract the cv-qualifiers of the member function from the
16320 implicit object parameter and place them on the function
16321 type to be restored later. */
16324 }
16343 /* Matched cases are handled by the ARG == PARM test above. */
16347 /* A non-type template parameter that is a variable should be a
16348 an integral constant, in which case, it whould have been
16349 folded into its (constant) value. So we should not be getting
16350 a variable here. */
16355 {
16363 {
16365 {
16367 /* We can unify against something with a trailing
16368 parameter pack. */
16370 else
16371 /* Since there is something following the pack
16372 expansion, we cannot unify this template argument
16373 list. */
16375 }
16376 }
16379 /* If we don't have enough arguments to satisfy the parameters
16380 (not counting the pack expression at the end), or we have
16381 too many arguments for a parameter list that doesn't end in
16382 a pack expression, we can't unify. */
16388 /* Unify all of the parameters that precede the (optional)
16389 pack expression. */
16391 {
16396 }
16404 }
16411 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
16412 or UNDERLYING_TYPE nodes. */
16416 /* Unification fails if we hit an error node. */
16420 /* An unresolved overload is a nondeduced context. */
16425 /* We must be looking at an expression. This can happen with
16426 something like:
16428 template <int I>
16429 void foo(S<I>, S<I + 2>);
16431 This is a "nondeduced context":
16433 [deduct.type]
16435 The nondeduced contexts are:
16437 --A type that is a template-id in which one or more of
16438 the template-arguments is an expression that references
16439 a template-parameter.
16441 In these cases, we assume deduction succeeded, but don't
16442 actually infer any unifications. */
16447 else
16449 }
16450 }
16451 #undef RECUR_AND_CHECK_FAILURE
16452 \f
16453 /* Note that DECL can be defined in this translation unit, if
16454 required. */
16456 static void
16458 {
16459 tree clone;
16463 }
16465 /* Called if RESULT is explicitly instantiated, or is a member of an
16466 explicitly instantiated class. */
16468 void
16470 {
16473 /* If this entity has already been written out, it's too late to
16474 make any modifications. */
16479 /* The TREE_PUBLIC flag for function declarations will have been
16480 set correctly by tsubst. */
16483 /* This might have been set by an earlier implicit instantiation. */
16488 else
16489 {
16491 /* Always make artificials weak. */
16494 /* For WIN32 we also want to put explicit instantiations in
16495 linkonce sections. */
16498 }
16500 /* If EXTERN_P, then this function will not be emitted -- unless
16501 followed by an explicit instantiation, at which point its linkage
16502 will be adjusted. If !EXTERN_P, then this function will be
16503 emitted here. In neither circumstance do we want
16504 import_export_decl to adjust the linkage. */
16506 }
16508 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
16509 important template arguments. If any are missing, we check whether
16510 they're important by using error_mark_node for substituting into any
16511 args that were used for partial ordering (the ones between ARGS and END)
16512 and seeing if it bubbles up. */
16514 static bool
16516 {
16521 {
16524 }
16526 {
16528 {
16532 }
16533 }
16535 }
16537 /* Given two function templates PAT1 and PAT2, return:
16539 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
16540 -1 if PAT2 is more specialized than PAT1.
16541 0 if neither is more specialized.
16543 LEN indicates the number of parameters we should consider
16544 (defaulted parameters should not be considered).
16546 The 1998 std underspecified function template partial ordering, and
16547 DR214 addresses the issue. We take pairs of arguments, one from
16548 each of the templates, and deduce them against each other. One of
16549 the templates will be more specialized if all the *other*
16550 template's arguments deduce against its arguments and at least one
16551 of its arguments *does* *not* deduce against the other template's
16552 corresponding argument. Deduction is done as for class templates.
16553 The arguments used in deduction have reference and top level cv
16554 qualifiers removed. Iff both arguments were originally reference
16555 types *and* deduction succeeds in both directions, the template
16556 with the more cv-qualified argument wins for that pairing (if
16557 neither is more cv-qualified, they both are equal). Unlike regular
16558 deduction, after all the arguments have been deduced in this way,
16559 we do *not* verify the deduced template argument values can be
16560 substituted into non-deduced contexts.
16562 The logic can be a bit confusing here, because we look at deduce1 and
16563 targs1 to see if pat2 is at least as specialized, and vice versa; if we
16564 can find template arguments for pat1 to make arg1 look like arg2, that
16565 means that arg2 is at least as specialized as arg1. */
16567 int
16569 {
16582 /* Remove the this parameter from non-static member functions. If
16583 one is a non-static member function and the other is not a static
16584 member function, remove the first parameter from that function
16585 also. This situation occurs for operator functions where we
16586 locate both a member function (with this pointer) and non-member
16587 operator (with explicit first operand). */
16589 {
16594 }
16596 {
16599 {
16600 len--;
16602 }
16603 }
16605 /* If only one is a conversion operator, they are unordered. */
16609 /* Consider the return type for a conversion function */
16611 {
16614 len++;
16615 }
16617 processing_template_decl++;
16623 /* Stop when an ellipsis is seen. */
16625 {
16634 {
16635 /* When both arguments are pack expansions, we need only
16636 unify the patterns themselves. */
16640 /* This is the last comparison we need to do. */
16642 }
16645 {
16648 }
16651 {
16654 }
16657 {
16658 /* Only of the args is a reference, see if we should apply
16659 array/function pointer decay to it. This is not part of
16660 DR214, but is, IMHO, consistent with the deduction rules
16661 for the function call itself, and with our earlier
16662 implementation of the underspecified partial ordering
16663 rules. (nathan). */
16665 {
16667 {
16670 /* FALLTHROUGH. */
16677 }
16678 }
16679 else
16680 {
16682 {
16685 /* FALLTHROUGH. */
16692 }
16693 }
16694 }
16700 {
16706 /* Setup the parameter vector, which contains only ARG1. */
16709 /* Setup the argument vector, which contains the remaining
16710 arguments. */
16720 /* We cannot deduce in the other direction, because ARG1 is
16721 a pack expansion but ARG2 is not. */
16723 }
16725 {
16731 /* Setup the parameter vector, which contains only ARG1. */
16734 /* Setup the argument vector, which contains the remaining
16735 arguments. */
16745 /* We cannot deduce in the other direction, because ARG2 is
16746 a pack expansion but ARG1 is not.*/
16748 }
16750 else
16751 {
16752 /* The normal case, where neither argument is a pack
16753 expansion. */
16760 }
16762 /* If we couldn't deduce arguments for tparms1 to make arg1 match
16763 arg2, then arg2 is not as specialized as arg1. */
16769 /* "If, for a given type, deduction succeeds in both directions
16770 (i.e., the types are identical after the transformations above)
16771 and if the type from the argument template is more cv-qualified
16772 than the type from the parameter template (as described above)
16773 that type is considered to be more specialized than the other. If
16774 neither type is more cv-qualified than the other then neither type
16775 is more specialized than the other." */
16779 {
16784 }
16787 /* We've failed to deduce something in either direction.
16788 These must be unordered. */
16793 /* We have already processed all of the arguments in our
16794 handing of the pack expansion type. */
16799 }
16801 /* "In most cases, all template parameters must have values in order for
16802 deduction to succeed, but for partial ordering purposes a template
16803 parameter may remain without a value provided it is not used in the
16804 types being used for partial ordering."
16806 Thus, if we are missing any of the targs1 we need to substitute into
16807 origs1, then pat2 is not as specialized as pat1. This can happen when
16808 there is a nondeduced context. */
16814 processing_template_decl--;
16816 /* All things being equal, if the next argument is a pack expansion
16817 for one function but not for the other, prefer the
16818 non-variadic function. FIXME this is bogus; see c++/41958. */
16822 {
16825 }
16831 else
16833 }
16835 /* Determine which of two partial specializations is more specialized.
16837 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
16838 to the first partial specialization. The TREE_VALUE is the
16839 innermost set of template parameters for the partial
16840 specialization. PAT2 is similar, but for the second template.
16842 Return 1 if the first partial specialization is more specialized;
16843 -1 if the second is more specialized; 0 if neither is more
16844 specialized.
16846 See [temp.class.order] for information about determining which of
16847 two templates is more specialized. */
16849 static int
16851 {
16852 tree targs;
16860 /* Just like what happens for functions, if we are ordering between
16861 different class template specializations, we may encounter dependent
16862 types in the arguments, and we need our dependency check functions
16863 to behave correctly. */
16869 {
16872 }
16878 {
16881 }
16884 /* In the case of a tie where at least one of the class templates
16885 has a parameter pack at the end, the template with the most
16886 non-packed parameters wins. */
16888 && any_deductions
16891 {
16897 /* We don't count the pack expansion at the end. */
16907 }
16910 }
16912 /* Return the template arguments that will produce the function signature
16913 DECL from the function template FN, with the explicit template
16914 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
16915 also match. Return NULL_TREE if no satisfactory arguments could be
16916 found. */
16918 static tree
16920 {
16923 tree decl_type;
16924 tree decl_arg_types;
16927 tree arg;
16929 /* Substitute the explicit template arguments into the type of DECL.
16930 The call to fn_type_unification will handle substitution into the
16931 FN. */
16934 {
16935 tree tmpl;
16936 tree converted_args;
16940 else
16941 /* We can get here for some invalid specializations. */
16944 converted_args
16947 tf_none,
16956 }
16958 /* Never do unification on the 'this' parameter. */
16977 }
16979 /* Return the innermost template arguments that, when applied to a
16980 template specialization whose innermost template parameters are
16981 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
16982 ARGS.
16984 For example, suppose we have:
16986 template <class T, class U> struct S {};
16987 template <class T> struct S<T*, int> {};
16989 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
16990 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
16991 int}. The resulting vector will be {double}, indicating that `T'
16992 is bound to `double'. */
16994 static tree
16996 {
16998 tree deduced_args;
16999 tree innermost_deduced_args;
17003 {
17007 innermost_deduced_args);
17008 }
17009 else
17022 /* Verify that nondeduced template arguments agree with the type
17023 obtained from argument deduction.
17025 For example:
17027 struct A { typedef int X; };
17028 template <class T, class U> struct C {};
17029 template <class T> struct C<T, typename T::X> {};
17031 Then with the instantiation `C<A, int>', we can deduce that
17032 `T' is `A' but unify () does not check whether `typename T::X'
17033 is `int'. */
17036 /* We only need to check the innermost arguments; the other
17037 arguments will always agree. */
17042 /* Now that we have bindings for all of the template arguments,
17043 ensure that the arguments deduced for the template template
17044 parameters have compatible template parameter lists. See the use
17045 of template_template_parm_bindings_ok_p in fn_type_unification
17046 for more information. */
17051 }
17053 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
17054 Return the TREE_LIST node with the most specialized template, if
17055 any. If there is no most specialized template, the error_mark_node
17056 is returned.
17058 Note that this function does not look at, or modify, the
17059 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
17060 returned is one of the elements of INSTANTIATIONS, callers may
17061 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
17062 and retrieve it from the value returned. */
17064 tree
17066 {
17073 {
17079 fate--;
17084 fate++;
17089 {
17090 /* Equally specialized, move to next function. If there
17091 is no next function, nothing's most specialized. */
17096 }
17097 }
17100 /* Now verify that champ is better than everything earlier in the
17101 instantiation list. */
17109 {
17112 }
17114 processing_template_decl--;
17120 }
17122 /* If DECL is a specialization of some template, return the most
17123 general such template. Otherwise, returns NULL_TREE.
17125 For example, given:
17127 template <class T> struct S { template <class U> void f(U); };
17129 if TMPL is `template <class U> void S<int>::f(U)' this will return
17130 the full template. This function will not trace past partial
17131 specializations, however. For example, given in addition:
17133 template <class T> struct S<T*> { template <class U> void f(U); };
17135 if TMPL is `template <class U> void S<int*>::f(U)' this will return
17136 `template <class T> template <class U> S<T*>::f(U)'. */
17138 tree
17140 {
17141 /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is
17142 an immediate specialization. */
17144 {
17148 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a
17149 template friend. */
17154 }
17156 /* Look for more and more general templates. */
17158 {
17159 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
17160 (See cp-tree.h for details.) */
17168 /* Stop if we run into an explicitly specialized class template. */
17175 }
17178 }
17180 /* Return the most specialized of the class template partial
17181 specializations of TMPL which can produce TYPE, a specialization of
17182 TMPL. The value returned is actually a TREE_LIST; the TREE_TYPE is
17183 a _TYPE node corresponding to the partial specialization, while the
17184 TREE_PURPOSE is the set of template arguments that must be
17185 substituted into the TREE_TYPE in order to generate TYPE.
17187 If the choice of partial specialization is ambiguous, a diagnostic
17188 is issued, and the error_mark_node is returned. If there are no
17189 partial specializations of TMPL matching TYPE, then NULL_TREE is
17190 returned. */
17192 static tree
17194 {
17196 tree t;
17197 tree champ;
17200 tree args;
17206 /* For determining which partial specialization to use, only the
17207 innermost args are interesting. */
17209 {
17212 }
17215 {
17216 tree partial_spec_args;
17217 tree spec_args;
17225 {
17228 /* Discard the outer levels of args, and then substitute in the
17229 template args from the enclosing class. */
17231 partial_spec_args = tsubst_template_args
17234 /* PARMS already refers to just the innermost parms, but the
17235 template parms in partial_spec_args had their levels lowered
17236 by tsubst, so we need to do the same for the parm list. We
17237 can't just tsubst the TREE_VEC itself, as tsubst wants to
17238 treat a TREE_VEC as an argument vector. */
17244 }
17246 partial_spec_args =
17249 partial_spec_args),
17260 partial_spec_args,
17261 args);
17263 {
17268 }
17269 }
17279 {
17282 ;
17283 else
17284 {
17286 {
17289 {
17292 }
17293 }
17295 }
17296 }
17300 {
17303 {
17306 }
17307 }
17310 {
17318 {
17321 }
17324 }
17327 }
17329 /* Explicitly instantiate DECL. */
17331 void
17333 {
17338 /* An error occurred, for which grokdeclarator has already issued
17339 an appropriate message. */
17342 {
17345 }
17347 {
17348 /* There is an asymmetry here in the way VAR_DECLs and
17349 FUNCTION_DECLs are handled by grokdeclarator. In the case of
17350 the latter, the DECL we get back will be marked as a
17351 template instantiation, and the appropriate
17352 DECL_TEMPLATE_INFO will be set up. This does not happen for
17353 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
17354 should handle VAR_DECLs as it currently handles
17355 FUNCTION_DECLs. */
17357 {
17360 }
17363 {
17366 }
17368 {
17373 }
17374 }
17376 {
17379 }
17380 else
17383 /* Check for various error cases. Note that if the explicit
17384 instantiation is valid the RESULT will currently be marked as an
17385 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
17386 until we get here. */
17389 {
17390 /* DR 259 [temp.spec].
17392 Both an explicit instantiation and a declaration of an explicit
17393 specialization shall not appear in a program unless the explicit
17394 instantiation follows a declaration of the explicit specialization.
17396 For a given set of template parameters, if an explicit
17397 instantiation of a template appears after a declaration of an
17398 explicit specialization for that template, the explicit
17399 instantiation has no effect. */
17401 }
17403 {
17404 /* [temp.spec]
17406 No program shall explicitly instantiate any template more
17407 than once.
17409 We check DECL_NOT_REALLY_EXTERN so as not to complain when
17410 the first instantiation was `extern' and the second is not,
17411 and EXTERN_P for the opposite case. */
17414 /* If an "extern" explicit instantiation follows an ordinary
17415 explicit instantiation, the template is instantiated. */
17418 }
17420 {
17423 }
17425 {
17428 }
17431 ;
17433 {
17436 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
17439 }
17440 else
17448 }
17450 static void
17452 {
17458 {
17461 }
17462 }
17464 /* Called from do_type_instantiation through binding_table_foreach to
17465 do recursive instantiation for the type bound in ENTRY. */
17466 static void
17468 {
17474 }
17476 /* Called from do_type_instantiation to instantiate a member
17477 (a member function or a static member variable) of an
17478 explicitly instantiated class template. */
17479 static void
17481 {
17486 }
17488 /* Perform an explicit instantiation of template class T. STORAGE, if
17489 non-null, is the RID for extern, inline or static. COMPLAIN is
17490 nonzero if this is called from the parser, zero if called recursively,
17491 since the standard is unclear (as detailed below). */
17493 void
17495 {
17505 {
17508 }
17513 {
17516 t);
17518 }
17521 {
17523 {
17525 {
17528 "ISO C++ 1998 forbids the use of %<extern%> on "
17530 }
17531 else
17533 "ISO C++ forbids the use of %qE"
17535 }
17543 else
17544 {
17546 storage);
17548 }
17549 }
17552 {
17553 /* DR 259 [temp.spec].
17555 Both an explicit instantiation and a declaration of an explicit
17556 specialization shall not appear in a program unless the explicit
17557 instantiation follows a declaration of the explicit specialization.
17559 For a given set of template parameters, if an explicit
17560 instantiation of a template appears after a declaration of an
17561 explicit specialization for that template, the explicit
17562 instantiation has no effect. */
17564 }
17566 {
17567 /* [temp.spec]
17569 No program shall explicitly instantiate any template more
17570 than once.
17572 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
17573 instantiation was `extern'. If EXTERN_P then the second is.
17574 These cases are OK. */
17581 /* If we've already instantiated the template, just return now. */
17584 }
17592 {
17593 tree tmp;
17595 /* In contrast to implicit instantiation, where only the
17596 declarations, and not the definitions, of members are
17597 instantiated, we have here:
17599 [temp.explicit]
17601 The explicit instantiation of a class template specialization
17602 implies the instantiation of all of its members not
17603 previously explicitly specialized in the translation unit
17604 containing the explicit instantiation.
17606 Of course, we can't instantiate member template classes, since
17607 we don't have any arguments for them. Note that the standard
17608 is unclear on whether the instantiation of the members are
17609 *explicit* instantiations or not. However, the most natural
17610 interpretation is that it should be an explicit instantiation. */
17625 }
17626 }
17628 /* Given a function DECL, which is a specialization of TMPL, modify
17629 DECL to be a re-instantiation of TMPL with the same template
17630 arguments. TMPL should be the template into which tsubst'ing
17631 should occur for DECL, not the most general template.
17633 One reason for doing this is a scenario like this:
17635 template <class T>
17636 void f(const T&, int i);
17638 void g() { f(3, 7); }
17640 template <class T>
17641 void f(const T& t, const int i) { }
17643 Note that when the template is first instantiated, with
17644 instantiate_template, the resulting DECL will have no name for the
17645 first parameter, and the wrong type for the second. So, when we go
17646 to instantiate the DECL, we regenerate it. */
17648 static void
17650 {
17651 /* The arguments used to instantiate DECL, from the most general
17652 template. */
17653 tree args;
17654 tree code_pattern;
17659 /* Make sure that we can see identifiers, and compute access
17660 correctly. */
17664 {
17665 tree decl_parm;
17666 tree pattern_parm;
17667 tree specs;
17681 specs);
17683 /* Merge parameter declarations. */
17686 pattern_parm
17690 {
17691 tree parm_type;
17692 tree attributes;
17697 NULL_TREE);
17703 {
17706 }
17709 }
17710 /* Merge any parameters that match with the function parameter
17711 pack. */
17713 {
17715 tree expanded_types;
17716 /* Expand the TYPE_PACK_EXPANSION that provides the types for
17717 the parameters in this function parameter pack. */
17722 {
17723 tree parm_type;
17724 tree attributes;
17727 /* Rename the parameter to include the index. */
17736 {
17739 }
17741 }
17742 }
17743 /* Merge additional specifiers from the CODE_PATTERN. */
17747 }
17749 {
17757 }
17758 else
17762 }
17764 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
17765 substituted to get DECL. */
17767 tree
17769 {
17772 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
17773 for the instantiation. This is not always the most general
17774 template. Consider, for example:
17776 template <class T>
17777 struct S { template <class U> void f();
17778 template <> void f<int>(); };
17780 and an instantiation of S<double>::f<int>. We want TD to be the
17781 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
17783 more general template. */
17785 /* We must also deal with friend templates. Given:
17787 template <class T> struct S {
17788 template <class U> friend void f() {};
17789 };
17791 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
17792 so far as the language is concerned, but that's still
17793 where we get the pattern for the instantiation from. On
17794 other hand, if the definition comes outside the class, say:
17796 template <class T> struct S {
17797 template <class U> friend void f();
17798 };
17799 template <class U> friend void f() {}
17801 we don't need to look any further. That's what the check for
17802 DECL_INITIAL is for. */
17806 {
17807 /* The present template, TD, should not be a definition. If it
17808 were a definition, we should be using it! Note that we
17809 cannot restructure the loop to just keep going until we find
17810 a template with a definition, since that might go too far if
17811 a specialization was declared, but not defined. */
17815 /* Fetch the more general template. */
17817 }
17820 }
17822 /* Returns true if we need to instantiate this template instance even if we
17823 know we aren't going to emit it.. */
17825 bool
17827 {
17828 /* We always instantiate inline functions so that we can inline them. An
17829 explicit instantiation declaration prohibits implicit instantiation of
17830 non-inline functions. With high levels of optimization, we would
17831 normally inline non-inline functions -- but we're not allowed to do
17832 that for "extern template" functions. Therefore, we check
17833 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
17836 /* And we need to instantiate static data members so that
17837 their initializers are available in integral constant
17838 expressions. */
17841 }
17843 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
17844 instantiate it now, modifying TREE_TYPE (fn). */
17846 void
17848 {
17862 {
17875 }
17876 else
17877 {
17878 /* This is an implicitly declared function, so NOEX is a list of
17879 other functions to evaluate and merge. */
17880 tree elt;
17883 {
17885 tree subspec;
17889 }
17890 }
17895 {
17898 else
17900 }
17901 }
17903 /* Produce the definition of D, a _DECL generated from a template. If
17904 DEFER_OK is nonzero, then we don't have to actually do the
17905 instantiation now; we just have to do it sometime. Normally it is
17906 an error if this is an explicit instantiation but D is undefined.
17907 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
17908 explicitly instantiated class template. */
17910 tree
17913 {
17915 tree gen_args;
17916 tree args;
17917 tree td;
17918 tree code_pattern;
17919 tree spec;
17920 tree gen_tmpl;
17926 /* This function should only be used to instantiate templates for
17927 functions and static member variables. */
17931 /* Variables are never deferred; if instantiation is required, they
17932 are instantiated right away. That allows for better code in the
17933 case that an expression refers to the value of the variable --
17934 if the variable has a constant value the referring expression can
17935 take advantage of that fact. */
17940 /* Don't instantiate cloned functions. Instead, instantiate the
17941 functions they cloned. */
17947 /* D has already been instantiated or explicitly specialized, so
17948 there's nothing for us to do here.
17950 It might seem reasonable to check whether or not D is an explicit
17951 instantiation, and, if so, stop here. But when an explicit
17952 instantiation is deferred until the end of the compilation,
17953 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
17954 the instantiation. */
17957 /* Check to see whether we know that this template will be
17958 instantiated in some other file, as with "extern template"
17959 extension. */
17962 /* In general, we do not instantiate such templates. */
17970 /* We should already have the extra args. */
17973 /* And what's in the hash table should match D. */
17977 /* This needs to happen before any tsubsting. */
17983 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
17984 for the instantiation. */
17988 /* We should never be trying to instantiate a member of a class
17989 template or partial specialization. */
17994 /* In the case of a friend template whose definition is provided
17995 outside the class, we may have too many arguments. Drop the
17996 ones we don't need. The same is true for specializations. */
17997 args = get_innermost_template_args
17999 else
18005 else
18008 /* We may be in the middle of deferred access check. Disable it now. */
18011 /* Unless an explicit instantiation directive has already determined
18012 the linkage of D, remember that a definition is available for
18013 this entity. */
18023 /* If D is a member of an explicitly instantiated class template,
18024 and no definition is available, treat it like an implicit
18025 instantiation. */
18028 {
18029 /* Leave linkage flags alone on instantiations with anonymous
18030 visibility. */
18032 {
18035 }
18037 }
18042 /* Recheck the substitutions to obtain any warning messages
18043 about ignoring cv qualifiers. Don't do this for artificial decls,
18044 as it breaks the context-sensitive substitution for lambda op(). */
18046 {
18050 /* Make sure that we can see identifiers, and compute access
18051 correctly. D is already the target FUNCTION_DECL with the
18052 right context. */
18056 {
18060 /* Don't simply tsubst the function type, as that will give
18061 duplicate warnings about poor parameter qualifications.
18062 The function arguments are the same as the decl_arguments
18063 without the top level cv qualifiers. */
18065 }
18069 }
18071 /* Defer all other templates, unless we have been explicitly
18072 forbidden from doing so. */
18074 template. */
18075 ! pattern_defined
18076 /* If it's OK to postpone instantiation, do so. */
18077 || defer_ok
18078 /* If this is a static data member that will be defined
18079 elsewhere, we don't want to instantiate the entire data
18080 member, but we do want to instantiate the initializer so that
18081 we can substitute that elsewhere. */
18083 {
18084 /* The definition of the static data member is now required so
18085 we must substitute the initializer. */
18089 {
18090 tree ns;
18091 tree init;
18098 args,
18101 /* Make sure the initializer is still constant, in case of
18102 circular dependency (template/instantiate6.C). */
18103 const_init
18107 LOOKUP_ONLYCONVERTING);
18110 }
18112 /* We restore the source position here because it's used by
18113 add_pending_template. */
18119 /* [temp.explicit]
18121 The definition of a non-exported function template, a
18122 non-exported member function template, or a non-exported
18123 member function or static data member of a class template
18124 shall be present in every translation unit in which it is
18125 explicitly instantiated. */
18129 /* If we're in unevaluated context, we just wanted to get the
18130 constant value; this isn't an odr use, so don't queue
18131 a full instantiation. */
18134 /* ??? Historically, we have instantiated inline functions, even
18135 when marked as "extern template". */
18139 }
18140 /* Tell the repository that D is available in this translation unit
18141 -- and see if it is supposed to be instantiated here. */
18143 {
18144 /* In a PCH file, despite the fact that the repository hasn't
18145 requested instantiation in the PCH it is still possible that
18146 an instantiation will be required in a file that includes the
18147 PCH. */
18150 /* Instantiate inline functions so that the inliner can do its
18151 job, even though we'll not be emitting a copy of this
18152 function. */
18155 }
18161 /* Mark D as instantiated so that recursive calls to
18162 instantiate_decl do not try to instantiate it again. */
18165 /* Regenerate the declaration in case the template has been modified
18166 by a subsequent redeclaration. */
18169 /* We already set the file and line above. Reset them now in case
18170 they changed as a result of calling regenerate_decl_from_template. */
18174 {
18175 tree init;
18178 /* Clear out DECL_RTL; whatever was there before may not be right
18179 since we've reset the type of the declaration. */
18183 /* The initializer is placed in DECL_INITIAL by
18184 regenerate_decl_from_template so we don't need to
18185 push/pop_access_scope again here. Pull it out so that
18186 cp_finish_decl can process it. */
18191 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
18192 initializer. That function will defer actual emission until
18193 we have a chance to determine linkage. */
18196 /* Enter the scope of D so that access-checking works correctly. */
18201 }
18205 {
18206 htab_t saved_local_specializations;
18207 tree subst_decl;
18208 tree tmpl_parm;
18209 tree spec_parm;
18211 /* Save away the current list, in case we are instantiating one
18212 template from within the body of another. */
18215 /* Set up the list of local specializations. */
18217 hash_local_specialization,
18218 eq_local_specializations,
18219 NULL);
18221 /* Set up context. */
18224 /* Create substitution entries for the parameters. */
18229 {
18233 }
18235 {
18237 {
18240 }
18241 else
18242 {
18243 /* Register the (value) argument pack as a specialization of
18244 TMPL_PARM, then move on. */
18247 }
18248 }
18251 /* Substitute into the body of the function. */
18256 /* Set the current input_location to the end of the function
18257 so that finish_function knows where we are. */
18260 /* We don't need the local specializations any more. */
18264 /* Finish the function. */
18267 }
18269 /* We're not deferring instantiation any more. */
18275 out:
18283 }
18285 /* Run through the list of templates that we wish we could
18286 instantiate, and instantiate any we can. RETRIES is the
18287 number of times we retry pending template instantiation. */
18289 void
18291 {
18295 /* Instantiating templates may trigger vtable generation. This in turn
18296 may require further template instantiations. We place a limit here
18297 to avoid infinite loop. */
18299 {
18303 " instantiating %q+D, possibly from virtual table generation"
18307 /* Pretend that we defined it. */
18310 }
18312 do
18313 {
18318 {
18323 {
18324 tree fn;
18327 {
18331 fn;
18339 }
18342 }
18343 else
18344 {
18347 {
18348 instantiation
18354 }
18358 }
18361 /* If INSTANTIATION has been instantiated, then we don't
18362 need to consider it again in the future. */
18364 else
18365 {
18368 }
18371 }
18373 }
18377 }
18379 /* Substitute ARGVEC into T, which is a list of initializers for
18380 either base class or a non-static data member. The TREE_PURPOSEs
18381 are DECLs, and the TREE_VALUEs are the initializer values. Used by
18382 instantiate_decl. */
18384 static tree
18386 {
18390 {
18391 tree decl;
18392 tree init;
18398 {
18399 tree expr;
18400 tree arg;
18402 /* Expand the base class expansion type into separate base
18403 classes. */
18405 tf_warning_or_error,
18406 NULL_TREE);
18410 /* We'll be building separate TREE_LISTs of arguments for
18411 each base. */
18417 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
18418 expand each argument in the TREE_VALUE of t. */
18424 /* VOID_TYPE_NODE is used to indicate
18425 value-initialization. */
18426 {
18429 }
18430 else
18431 {
18432 /* Substitute parameter packs into each argument in the
18433 TREE_LIST. */
18436 {
18437 tree expanded_exprs;
18439 /* Expand the argument. */
18441 expanded_exprs
18443 tf_warning_or_error,
18444 NULL_TREE);
18448 /* Prepend each of the expanded expressions to the
18449 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
18451 {
18456 }
18457 }
18460 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
18461 since we built them backwards. */
18463 {
18466 }
18467 }
18468 }
18471 {
18473 {
18477 }
18478 else
18479 {
18493 }
18496 {
18500 }
18501 }
18502 }
18504 }
18506 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
18508 static void
18510 {
18515 else
18517 }
18519 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
18520 is the instantiation (which should have been created with
18521 start_enum) and ARGS are the template arguments to use. */
18523 static void
18525 {
18526 tree e;
18532 {
18533 tree value;
18534 tree decl;
18537 /* Note that in a template enum, the TREE_VALUE is the
18538 CONST_DECL, not the corresponding INTEGER_CST. */
18543 /* Give this enumeration constant the correct access. */
18546 /* Actually build the enumerator itself. */
18547 build_enumerator
18549 }
18559 }
18561 /* DECL is a FUNCTION_DECL that is a template specialization. Return
18562 its type -- but without substituting the innermost set of template
18563 arguments. So, innermost set of template parameters will appear in
18564 the type. */
18566 tree
18568 {
18569 tree fn_type;
18570 tree tmpl;
18571 tree targs;
18572 tree tparms;
18580 /* There should be as many levels of arguments as there are levels
18581 of parameters. */
18587 /* No substitution is necessary. */
18588 ;
18589 else
18590 {
18592 tree partial_args;
18594 /* Replace the innermost level of the TARGS with NULL_TREEs to
18595 let tsubst know not to substitute for those parameters. */
18604 /* Make sure that we can see identifiers, and compute access
18605 correctly. */
18609 /* Now, do the (partial) substitution to figure out the
18610 appropriate function type. */
18614 /* Substitute into the template parameters to obtain the real
18615 innermost set of parameters. This step is important if the
18616 innermost set of template parameters contains value
18617 parameters whose types depend on outer template parameters. */
18622 }
18625 }
18627 /* Return truthvalue if we're processing a template different from
18628 the last one involved in diagnostics. */
18629 int
18631 {
18633 }
18635 /* Remember current template involved in diagnostics. */
18636 void
18638 {
18640 }
18644 {
18646 }
18648 /* [temp.param] Check that template non-type parm TYPE is of an allowable
18649 type. Return zero for ok, nonzero for disallowed. Issue error and
18650 warning messages under control of COMPLAIN. */
18652 static int
18654 {
18671 }
18673 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
18674 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
18676 static bool
18678 {
18679 tree scope;
18681 /* [temp.dep.type]
18683 A type is dependent if it is:
18685 -- a template parameter. Template template parameters are types
18686 for us (since TYPE_P holds true for them) so we handle
18687 them here. */
18691 /* -- a qualified-id with a nested-name-specifier which contains a
18692 class-name that names a dependent type or whose unqualified-id
18693 names a dependent type. */
18696 /* -- a cv-qualified type where the cv-unqualified type is
18697 dependent. */
18699 /* -- a compound type constructed from any dependent type. */
18709 {
18710 tree arg_type;
18715 arg_type;
18720 }
18721 /* -- an array type constructed from any dependent type or whose
18722 size is specified by a constant expression that is
18723 value-dependent.
18725 We checked for type- and value-dependence of the bounds in
18726 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
18728 {
18733 }
18735 /* -- a template-id in which either the template name is a template
18736 parameter ... */
18739 /* ... or any of the template arguments is a dependent type or
18740 an expression that is type-dependent or value-dependent. */
18742 && (any_dependent_template_arguments_p
18746 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
18747 dependent; if the argument of the `typeof' expression is not
18748 type-dependent, then it should already been have resolved. */
18754 /* A template argument pack is dependent if any of its packed
18755 arguments are. */
18757 {
18763 }
18765 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
18766 be template parameters. */
18770 /* The standard does not specifically mention types that are local
18771 to template functions or local classes, but they should be
18772 considered dependent too. For example:
18774 template <int I> void f() {
18775 enum E { a = I };
18776 S<sizeof (E)> s;
18777 }
18779 The size of `E' cannot be known until the value of `I' has been
18780 determined. Therefore, `E' must be considered dependent. */
18784 /* Don't use type_dependent_expression_p here, as it can lead
18785 to infinite recursion trying to determine whether a lambda
18786 nested in a lambda is dependent (c++/47687). */
18790 && (any_dependent_template_arguments_p
18794 /* Other types are non-dependent. */
18796 }
18798 /* Returns TRUE if TYPE is dependent, in the sense of
18799 [temp.dep.type]. Note that a NULL type is considered dependent. */
18801 bool
18803 {
18804 /* If there are no template parameters in scope, then there can't be
18805 any dependent types. */
18807 {
18808 /* If we are not processing a template, then nobody should be
18809 providing us with a dependent type. */
18813 }
18815 /* If the type is NULL, we have not computed a type for the entity
18816 in question; in that case, the type is dependent. */
18820 /* Erroneous types can be considered non-dependent. */
18824 /* If we have not already computed the appropriate value for TYPE,
18825 do so now. */
18827 {
18830 }
18833 }
18835 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
18836 lookup. In other words, a dependent type that is not the current
18837 instantiation. */
18839 bool
18841 {
18844 }
18846 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
18847 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
18848 expression. */
18850 /* Note that this predicate is not appropriate for general expressions;
18851 only constant expressions (that satisfy potential_constant_expression)
18852 can be tested for value dependence.
18854 We should really also have a predicate for "instantiation-dependent".
18856 fold_non_dependent_expr: fold if constant and not type-dependent and not value-dependent.
18857 (what about instantiation-dependent constant-expressions?)
18858 is_late_template_attribute: defer if instantiation-dependent.
18859 compute_array_index_type: proceed if constant and not t- or v-dependent
18860 if instantiation-dependent, need to remember full expression
18861 uses_template_parms: FIXME - need to audit callers
18862 tsubst_decl [function_decl]: Why is this using value_dependent_expression_p?
18863 dependent_type_p [array_type]: dependent if index type is dependent
18864 (or non-constant?)
18865 static_assert - instantiation-dependent */
18867 bool
18869 {
18873 /* A name declared with a dependent type. */
18878 {
18880 /* A name that has not been looked up -- must be dependent. */
18884 /* A non-type template parm. */
18888 /* A non-type template parm. */
18894 /* A constant with literal type and is initialized
18895 with an expression that is value-dependent. */
18907 /* These expressions are value-dependent if the type to which
18908 the cast occurs is dependent or the expression being casted
18909 is value-dependent. */
18910 {
18916 /* A functional cast has a list of operands. */
18919 {
18920 /* If there are no operands, it must be an expression such
18921 as "int()". This should not happen for aggregate types
18922 because it would form non-constant expressions. */
18927 }
18933 }
18938 /* A `sizeof' expression is value-dependent if the operand is
18939 type-dependent or is a pack expansion. */
18948 /* An 'encode' expression is value-dependent if the operand is
18949 type-dependent. */
18958 {
18961 }
18968 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
18969 is value-dependent. */
18970 {
18979 }
18982 {
18986 }
18997 {
19001 }
19004 {
19011 {
19013 /* In a call to a constexpr member function, look through the
19014 implicit ADDR_EXPR on the object argument so that it doesn't
19015 cause the call to be considered value-dependent. We also
19016 look through it in potential_constant_expression. */
19023 }
19025 }
19028 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
19029 type-dependent. */
19033 {
19035 tree val;
19040 }
19043 /* A constant expression is value-dependent if any subexpression is
19044 value-dependent. */
19046 {
19053 {
19057 {
19060 /* In some cases, some of the operands may be missing.l
19061 (For example, in the case of PREDECREMENT_EXPR, the
19062 amount to increment by may be missing.) That doesn't
19063 make the expression dependent. */
19066 }
19067 }
19071 }
19073 }
19075 /* The expression is not value-dependent. */
19077 }
19079 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
19080 [temp.dep.expr]. Note that an expression with no type is
19081 considered dependent. Other parts of the compiler arrange for an
19082 expression with type-dependent subexpressions to have no type, so
19083 this function doesn't have to be fully recursive. */
19085 bool
19087 {
19094 /* An unresolved name is always dependent. */
19099 /* Some expression forms are never type-dependent. */
19112 /* The types of these expressions depends only on the type to which
19113 the cast occurs. */
19121 /* The types of these expressions depends only on the type created
19122 by the expression. */
19125 {
19126 /* For NEW_EXPR tree nodes created inside a template, either
19127 the object type itself or a TREE_LIST may appear as the
19128 operand 1. */
19131 /* This is an array type. We need to check array dimensions
19132 as well. */
19134 || value_dependent_expression_p
19136 else
19138 }
19141 {
19145 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
19146 contains an identifier associated by name lookup with one or more
19147 declarations declared with a dependent type, or...a
19148 nested-name-specifier or qualified-id that names a member of an
19149 unknown specialization. */
19152 }
19157 && (any_dependent_template_arguments_p
19169 {
19170 tree elt;
19174 {
19177 }
19179 }
19181 /* A static data member of the current instantiation with incomplete
19182 array type is type-dependent, as the definition and specializations
19183 can have different bounds. */
19191 {
19196 {
19202 }
19203 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
19211 {
19216 }
19221 {
19225 }
19227 }
19232 }
19234 /* Like type_dependent_expression_p, but it also works while not processing
19235 a template definition, i.e. during substitution or mangling. */
19237 bool
19239 {
19245 }
19247 /* Returns TRUE if ARGS contains a type-dependent expression. */
19249 bool
19251 {
19253 tree arg;
19256 {
19259 }
19261 }
19263 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
19264 expressions) contains any type-dependent expressions. */
19266 bool
19268 {
19274 }
19276 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
19277 expressions) contains any value-dependent expressions. */
19279 bool
19281 {
19287 }
19289 /* Returns TRUE if the ARG (a template argument) is dependent. */
19291 bool
19293 {
19297 /* Assume a template argument that was wrongly written by the user
19298 is dependent. This is consistent with what
19299 any_dependent_template_arguments_p [that calls this function]
19300 does. */
19311 {
19315 {
19318 }
19321 }
19324 else
19327 }
19329 /* Returns true if ARGS (a collection of template arguments) contains
19330 any types that require structural equality testing. */
19332 bool
19334 {
19344 {
19347 {
19353 {
19354 /* Look inside the argument pack. */
19357 }
19360 {
19374 }
19375 }
19376 }
19379 }
19381 /* Returns true if ARGS (a collection of template arguments) contains
19382 any dependent arguments. */
19384 bool
19386 {
19396 {
19401 }
19404 }
19406 /* Returns TRUE if the template TMPL is dependent. */
19408 bool
19410 {
19412 {
19414 {
19418 }
19420 }
19422 /* Template template parameters are dependent. */
19426 /* So are names that have not been looked up. */
19430 /* So are member templates of dependent classes. */
19434 }
19436 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
19438 bool
19440 {
19443 }
19445 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
19446 is dependent. */
19448 bool
19450 {
19457 {
19478 {
19482 }
19486 {
19490 {
19495 }
19496 }
19497 }
19500 }
19502 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
19503 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
19504 no such TYPE can be found. Note that this function peers inside
19505 uninstantiated templates and therefore should be used only in
19506 extremely limited situations. ONLY_CURRENT_P restricts this
19507 peering to the currently open classes hierarchy (which is required
19508 when comparing types). */
19510 tree
19512 {
19513 tree scope;
19514 tree name;
19515 tree decl;
19517 tree pushed_scope;
19518 tree result;
19523 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
19524 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
19525 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
19526 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
19527 identifier of the TYPENAME_TYPE anymore.
19528 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
19529 TYPENAME_TYPE instead, we avoid messing up with a possible
19530 typedef variant case. */
19533 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
19534 it first before we can figure out what NAME refers to. */
19537 /* If we don't know what SCOPE refers to, then we cannot resolve the
19538 TYPENAME_TYPE. */
19541 /* If the SCOPE is a template type parameter, we have no way of
19542 resolving the name. */
19545 /* If the SCOPE is not the current instantiation, there's no reason
19546 to look inside it. */
19549 /* If this is a typedef, we don't want to look inside (c++/11987). */
19552 /* If SCOPE isn't the template itself, it will not have a valid
19553 TYPE_FIELDS list. */
19555 /* scope is either the template itself or a compatible instantiation
19556 like X<T>, so look up the name in the original template. */
19558 else
19559 /* scope is a partial instantiation, so we can't do the lookup or we
19560 will lose the template arguments. */
19562 /* Enter the SCOPE so that name lookup will be resolved as if we
19563 were in the class definition. In particular, SCOPE will no
19564 longer be considered a dependent type. */
19566 /* Look up the declaration. */
19571 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
19572 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
19577 {
19581 }
19584 {
19585 tree tmpl;
19586 tree args;
19587 /* Obtain the template and the arguments. */
19590 /* Instantiate the template. */
19596 }
19598 /* Leave the SCOPE. */
19602 /* If we failed to resolve it, return the original typename. */
19606 /* If lookup found a typename type, resolve that too. */
19608 {
19609 /* Ill-formed programs can cause infinite recursion here, so we
19610 must catch that. */
19614 }
19616 /* Qualify the resulting type. */
19622 }
19624 /* EXPR is an expression which is not type-dependent. Return a proxy
19625 for EXPR that can be used to compute the types of larger
19626 expressions containing EXPR. */
19628 tree
19630 {
19631 tree inner_expr;
19633 #ifdef ENABLE_CHECKING
19634 /* Try to get a constant value for all non-type-dependent expressions in
19635 order to expose bugs in *_dependent_expression_p and constexpr. */
19638 #endif
19640 /* Preserve OVERLOADs; the functions must be available to resolve
19641 types. */
19652 /* There is no need to return a proxy for a variable. */
19655 /* Preserve string constants; conversions from string constants to
19656 "char *" are allowed, even though normally a "const char *"
19657 cannot be used to initialize a "char *". */
19660 /* Preserve arithmetic constants, as an optimization -- there is no
19661 reason to create a new node. */
19664 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
19665 There is at least one place where we want to know that a
19666 particular expression is a throw-expression: when checking a ?:
19667 expression, there are special rules if the second or third
19668 argument is a throw-expression. */
19687 /* If the type is unknown, it can't really be non-dependent */
19690 /* Otherwise, build a NON_DEPENDENT_EXPR. */
19692 }
19694 /* ARGS is a vector of expressions as arguments to a function call.
19695 Replace the arguments with equivalent non-dependent expressions.
19696 This modifies ARGS in place. */
19698 void
19700 {
19702 tree arg;
19705 {
19709 }
19710 }
19712 /* Returns a type which represents 'auto'. We use a TEMPLATE_TYPE_PARM
19713 with a level one deeper than the actual template parms. */
19715 tree
19717 {
19730 }
19732 /* Given type ARG, return std::initializer_list<ARG>. */
19734 static tree
19736 {
19737 tree std_init_list = namespace_binding
19739 tree argvec;
19741 {
19745 }
19750 }
19752 /* Replace auto in TYPE with std::initializer_list<auto>. */
19754 static tree
19756 {
19763 }
19765 /* walk_tree helper for do_auto_deduction. */
19767 static tree
19770 {
19771 /* Is this a variable with the type we're looking for? */
19775 else
19777 }
19779 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
19780 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
19782 tree
19784 {
19787 tree decl;
19793 /* Not enough information to try this yet. */
19796 /* The name of the object being declared shall not appear in the
19797 initializer expression. */
19800 {
19804 }
19806 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
19807 with either a new invented type template parameter U or, if the
19808 initializer is a braced-init-list (8.5.4), with
19809 std::initializer_list<U>. */
19825 {
19827 /* Try again at instantiation time. */
19830 /* If type is error_mark_node a diagnostic must have been
19831 emitted by now. Also, having a mention to '<type error>'
19832 in the diagnostic is not really useful to the user. */
19835 }
19837 /* If the list of declarators contains more than one declarator, the type
19838 of each declared variable is determined as described above. If the
19839 type deduced for the template parameter U is not the same in each
19840 deduction, the program is ill-formed. */
19843 {
19847 }
19853 }
19855 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
19856 result. */
19858 tree
19860 {
19861 tree argvec;
19868 /* For a late-specified return type in a template type-parameter, we
19869 need to add a dummy argument level for its parmlist. */
19870 argvec = add_to_template_args
19875 }
19877 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto'. */
19879 bool
19881 {
19885 else
19887 }
19889 /* Returns true iff TYPE contains a use of 'auto'. Since auto can only
19890 appear as a type-specifier for the declaration in question, we don't
19891 have to look through the whole type. */
19893 tree
19895 {
19912 }
19914 /* For a given template T, return the vector of typedefs referenced
19915 in T for which access check is needed at T instantiation time.
19916 T is either a FUNCTION_DECL or a RECORD_TYPE.
19917 Those typedefs were added to T by the function
19918 append_type_to_template_for_access_check. */
19922 {
19923 tree ti;
19934 {
19939 }
19942 }
19944 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
19945 tied to T. That list of typedefs will be access checked at
19946 T instantiation time.
19947 T is either a FUNCTION_DECL or a RECORD_TYPE.
19948 TYPE_DECL is a TYPE_DECL node representing a typedef.
19949 SCOPE is the scope through which TYPE_DECL is accessed.
19950 LOCATION is the location of the usage point of TYPE_DECL.
19952 This function is a subroutine of
19953 append_type_to_template_for_access_check. */
19955 static void
19957 tree type_decl,
19958 tree scope,
19959 location_t location)
19960 {
19961 qualified_typedef_usage_t typedef_usage;
19962 tree ti;
19969 && type_decl
19985 }
19987 /* Append TYPE_DECL to the template TEMPL.
19988 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
19989 At TEMPL instanciation time, TYPE_DECL will be checked to see
19990 if it can be accessed through SCOPE.
19991 LOCATION is the location of the usage point of TYPE_DECL.
19993 e.g. consider the following code snippet:
19995 class C
19996 {
19997 typedef int myint;
19998 };
20000 template<class U> struct S
20001 {
20002 C::myint mi; // <-- usage point of the typedef C::myint
20003 };
20005 S<char> s;
20007 At S<char> instantiation time, we need to check the access of C::myint
20008 In other words, we need to check the access of the myint typedef through
20009 the C scope. For that purpose, this function will add the myint typedef
20010 and the scope C through which its being accessed to a list of typedefs
20011 tied to the template S. That list will be walked at template instantiation
20012 time and access check performed on each typedefs it contains.
20013 Note that this particular code snippet should yield an error because
20014 myint is private to C. */
20016 void
20018 tree type_decl,
20019 tree scope,
20020 location_t location)
20021 {
20027 /* Make sure we don't append the type to the template twice. */
20036 }
20038 /* Set up the hash tables for template instantiations. */
20040 void
20042 {
20044 hash_specialization,
20045 eq_specializations,
20046 ggc_free);
20048 hash_specialization,
20049 eq_specializations,
20050 ggc_free);
20051 }
20053 /* Print stats about the template hash tables for -fstats. */
20055 void
20057 {
20066 }