| blob | ecb013ecaee5dab46c76f81ec44b9facb63397d3 |
1 /* Handle parameterized types (templates) for GNU C++.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
3 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011, 2012
4 Free Software Foundation, Inc.
5 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
6 Rewritten by Jason Merrill (jason@cygnus.com).
8 This file is part of GCC.
10 GCC is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3, or (at your option)
13 any later version.
15 GCC is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with GCC; see the file COPYING3. If not see
22 <http://www.gnu.org/licenses/>. */
24 /* Known bugs or deficiencies include:
26 all methods must be provided in header files; can't use a source
27 file that contains only the method templates and "just win". */
47 /* The type of functions taking a tree, and some additional data, and
48 returning an int. */
51 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
52 instantiations have been deferred, either because their definitions
53 were not yet available, or because we were putting off doing the work. */
57 };
72 /* Live only within one (recursive) call to tsubst_expr. We use
73 this to pass the statement expression node from the STMT_EXPR
74 to the EXPR_STMT that is its result. */
77 /* A map from local variable declarations in the body of the template
78 presently being instantiated to the corresponding instantiated
79 local variables. */
82 /* True if we've recursed into fn_type_unification too many times. */
86 {
87 tree tmpl;
88 tree args;
89 tree spec;
93 htab_t decl_specializations;
96 htab_t type_specializations;
98 /* Contains canonical template parameter types. The vector is indexed by
99 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
100 TREE_LIST, whose TREE_VALUEs contain the canonical template
101 parameters of various types and levels. */
104 #define UNIFY_ALLOW_NONE 0
105 #define UNIFY_ALLOW_MORE_CV_QUAL 1
106 #define UNIFY_ALLOW_LESS_CV_QUAL 2
107 #define UNIFY_ALLOW_DERIVED 4
108 #define UNIFY_ALLOW_INTEGER 8
109 #define UNIFY_ALLOW_OUTER_LEVEL 16
110 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
111 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
114 tbr_incomplete_type,
115 tbr_ambiguous_baseclass,
116 tbr_success
117 };
138 tree);
200 location_t);
209 /* Make the current scope suitable for access checking when we are
210 processing T. T can be FUNCTION_DECL for instantiated function
211 template, VAR_DECL for static member variable, or TYPE_DECL for
212 alias template (needed by instantiate_decl). */
214 static void
216 {
225 else
229 {
230 saved_access_scope = tree_cons
233 }
234 }
236 /* Restore the scope set up by push_access_scope. T is the node we
237 are processing. */
239 static void
241 {
243 {
246 }
250 else
252 }
254 /* Do any processing required when DECL (a member template
255 declaration) is finished. Returns the TEMPLATE_DECL corresponding
256 to DECL, unless it is a specialization, in which case the DECL
257 itself is returned. */
259 tree
261 {
268 {
269 tree type;
277 {
281 }
283 }
287 {
289 {
292 }
293 else
295 }
296 else
300 }
302 /* Create a template info node. */
304 tree
306 {
311 }
313 /* Return the template info node corresponding to T, whatever T is. */
315 tree
317 {
335 }
337 /* Returns the template nesting level of the indicated class TYPE.
339 For example, in:
340 template <class T>
341 struct A
342 {
343 template <class U>
344 struct B {};
345 };
347 A<T>::B<U> has depth two, while A<T> has depth one.
348 Both A<T>::B<int> and A<int>::B<U> have depth one, if
349 they are instantiations, not specializations.
351 This function is guaranteed to return 0 if passed NULL_TREE so
352 that, for example, `template_class_depth (current_class_type)' is
353 always safe. */
355 int
357 {
364 {
370 }
373 }
375 /* Subroutine of maybe_begin_member_template_processing.
376 Returns true if processing DECL needs us to push template parms. */
378 static bool
380 {
386 }
388 /* Subroutine of maybe_begin_member_template_processing.
389 Push the template parms in PARMS, starting from LEVELS steps into the
390 chain, and ending at the beginning, since template parms are listed
391 innermost first. */
393 static void
395 {
403 current_template_parms
409 NULL);
411 {
420 {
427 {
428 /* Make a CONST_DECL as is done in process_template_parm.
429 It is ugly that we recreate this here; the original
430 version built in process_template_parm is no longer
431 available. */
441 }
446 }
447 }
448 }
450 /* Restore the template parameter context for a member template or
451 a friend template defined in a class definition. */
453 void
455 {
456 tree parms;
460 {
465 {
468 }
471 }
473 /* Remember how many levels of template parameters we pushed so that
474 we can pop them later. */
476 }
478 /* Undo the effects of maybe_begin_member_template_processing. */
480 void
482 {
491 {
495 }
496 }
498 /* Return a new template argument vector which contains all of ARGS,
499 but has as its innermost set of arguments the EXTRA_ARGS. */
501 static tree
503 {
504 tree new_args;
522 }
524 /* Like add_to_template_args, but only the outermost ARGS are added to
525 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
526 (EXTRA_ARGS) levels are added. This function is used to combine
527 the template arguments from a partial instantiation with the
528 template arguments used to attain the full instantiation from the
529 partial instantiation. */
531 static tree
533 {
534 tree new_args;
536 /* If there are more levels of EXTRA_ARGS than there are ARGS,
537 something very fishy is going on. */
540 /* If *all* the new arguments will be the EXTRA_ARGS, just return
541 them. */
545 /* For the moment, we make ARGS look like it contains fewer levels. */
550 /* Now, we restore ARGS to its full dimensions. */
554 }
556 /* Return the N levels of innermost template arguments from the ARGS. */
558 tree
560 {
561 tree new_args;
567 /* If N is 1, just return the innermost set of template arguments. */
571 /* If we're not removing anything, just return the arguments we were
572 given. */
578 /* Make a new set of arguments, not containing the outer arguments. */
585 }
587 /* The inverse of get_innermost_template_args: Return all but the innermost
588 EXTRA_LEVELS levels of template arguments from the ARGS. */
590 static tree
592 {
593 tree new_args;
599 /* If N is 1, just return the outermost set of template arguments. */
603 /* If we're not removing anything, just return the arguments we were
604 given. */
609 /* Make a new set of arguments, not containing the inner arguments. */
616 }
618 /* We've got a template header coming up; push to a new level for storing
619 the parms. */
621 void
623 {
624 /* We use a non-tag-transparent scope here, which causes pushtag to
625 put tags in this scope, rather than in the enclosing class or
626 namespace scope. This is the right thing, since we want
627 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
628 global template class, push_template_decl handles putting the
629 TEMPLATE_DECL into top-level scope. For a nested template class,
630 e.g.:
632 template <class T> struct S1 {
633 template <class T> struct S2 {};
634 };
636 pushtag contains special code to call pushdecl_with_scope on the
637 TEMPLATE_DECL for S2. */
642 }
644 /* This routine is called when a specialization is declared. If it is
645 invalid to declare a specialization here, an error is reported and
646 false is returned, otherwise this routine will return true. */
648 static bool
650 {
653 /* [temp.expl.spec]
655 An explicit specialization shall be declared in the namespace of
656 which the template is a member, or, for member templates, in the
657 namespace of which the enclosing class or enclosing class
658 template is a member. An explicit specialization of a member
659 function, member class or static data member of a class template
660 shall be declared in the namespace of which the class template
661 is a member. */
663 {
666 }
668 /* [temp.expl.spec]
670 In an explicit specialization declaration for a member of a class
671 template or a member template that appears in namespace scope,
672 the member template and some of its enclosing class templates may
673 remain unspecialized, except that the declaration shall not
674 explicitly specialize a class member template if its enclosing
675 class templates are not explicitly specialized as well. */
677 {
680 }
683 }
685 /* We've just seen template <>. */
687 bool
689 {
693 }
695 /* Called at then end of processing a declaration preceded by
696 template<>. */
698 void
700 {
703 }
705 /* Any template <>'s that we have seen thus far are not referring to a
706 function specialization. */
708 void
710 {
713 }
715 /* We've just seen a template header. If SPECIALIZATION is nonzero,
716 it was of the form template <>. */
718 static void
720 {
722 template_header_count++;
723 }
725 /* We're beginning an explicit instantiation. */
727 void
729 {
732 }
735 void
737 {
740 }
742 /* An explicit specialization or partial specialization of TMPL is being
743 declared. Check that the namespace in which the specialization is
744 occurring is permissible. Returns false iff it is invalid to
745 specialize TMPL in the current namespace. */
747 static bool
749 {
752 /* [tmpl.expl.spec]
754 An explicit specialization shall be declared in the namespace of
755 which the template is a member, or, for member templates, in the
756 namespace of which the enclosing class or enclosing class
757 template is a member. An explicit specialization of a member
758 function, member class or static data member of a class template
759 shall be declared in the namespace of which the class template is
760 a member. */
763 {
766 }
768 /* Same or super-using namespace. */
770 else
771 {
775 }
776 }
778 /* SPEC is an explicit instantiation. Check that it is valid to
779 perform this explicit instantiation in the current namespace. */
781 static void
783 {
784 tree ns;
786 /* DR 275: An explicit instantiation shall appear in an enclosing
787 namespace of its template. */
793 }
795 /* The TYPE is being declared. If it is a template type, that means it
796 is a partial specialization. Do appropriate error-checking. */
798 tree
800 {
801 tree context;
807 {
811 }
816 /* Consider non-class instantiations of alias templates as
817 well. */
822 {
823 /* This is for ordinary explicit specialization and partial
824 specialization of a template class such as:
826 template <> class C<int>;
828 or:
830 template <class T> class C<T*>;
832 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
837 {
842 {
846 }
847 }
853 {
857 }
858 }
864 {
865 /* This is for an explicit specialization of member class
866 template according to [temp.expl.spec/18]:
868 template <> template <class U> class C<int>::D;
870 The context `C<int>' must be an implicit instantiation.
871 Otherwise this is just a member class template declared
872 earlier like:
874 template <> class C<int> { template <class U> class D; };
875 template <> template <class U> class C<int>::D;
877 In the first case, `C<int>::D' is a specialization of `C<T>::D'
878 while in the second case, `C<int>::D' is a primary template
879 and `C<T>::D' may not exist. */
883 {
884 tree t;
889 {
892 }
894 /* Check for invalid specialization after instantiation:
896 template <> template <> class C<int>::D<int>;
897 template <> template <class U> class C<int>::D; */
901 {
904 {
905 /* We already have a full specialization of this partial
906 instantiation. Reassign it to the new member
907 specialization template. */
908 spec_entry elt;
925 }
927 /* But if we've had an implicit instantiation, that's a
928 problem ([temp.expl.spec]/6). */
931 }
933 /* Mark TYPE as a specialization. And as a result, we only
934 have one level of template argument for the innermost
935 class template. */
940 }
941 }
943 {
944 /* Someday C++0x may allow for enum template specialization. */
949 else
950 {
953 }
954 }
957 }
959 /* Returns nonzero if we can optimize the retrieval of specializations
960 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
961 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
965 {
968 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
969 parameter. */
971 /* The optimized lookup depends on the fact that the
972 template arguments for the member function template apply
973 purely to the containing class, which is not true if the
974 containing class is an explicit or partial
975 specialization. */
979 /* It is possible to have a template that is not a member
980 template and is not a member of a template class:
982 template <typename T>
983 struct S { friend A::f(); };
985 Here, the friend function is a template, but the context does
986 not have template information. The optimized lookup relies
987 on having ARGS be the template arguments for both the class
988 and the function template. */
990 }
992 /* Retrieve the specialization (in the sense of [temp.spec] - a
993 specialization is either an instantiation or an explicit
994 specialization) of TMPL for the given template ARGS. If there is
995 no such specialization, return NULL_TREE. The ARGS are a vector of
996 arguments, or a vector of vectors of arguments, in the case of
997 templates with more than one level of parameters.
999 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1000 then we search for a partial specialization matching ARGS. This
1001 parameter is ignored if TMPL is not a class template. */
1003 static tree
1005 {
1011 /* There should be as many levels of arguments as there are
1012 levels of parameters. */
1017 {
1018 tree class_template;
1019 tree class_specialization;
1021 tree fns;
1024 /* The template arguments actually apply to the containing
1025 class. Find the class specialization with those
1026 arguments. */
1028 class_specialization
1032 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1033 for the specialization. */
1037 /* Iterate through the methods with the indicated name, looking
1038 for the one that has an instance of TMPL. */
1041 {
1044 /* using-declarations can add base methods to the method vec,
1045 and we don't want those here. */
1048 }
1050 }
1051 else
1052 {
1054 spec_entry elt;
1055 htab_t specializations;
1063 else
1071 }
1074 }
1076 /* Like retrieve_specialization, but for local declarations. */
1078 static tree
1080 {
1088 }
1090 /* Returns nonzero iff DECL is a specialization of TMPL. */
1092 int
1094 {
1095 tree t;
1098 {
1104 }
1105 else
1106 {
1115 }
1118 }
1120 /* Returns nonzero iff DECL is a specialization of friend declaration
1121 FRIEND_DECL according to [temp.friend]. */
1123 bool
1125 {
1132 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1133 of a template class, we want to check if DECL is a specialization
1134 if this. */
1138 {
1139 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1142 }
1147 /* There is nothing to do if this is not a template friend. */
1154 /* [temp.friend/6]
1155 A member of a class template may be declared to be a friend of a
1156 non-template class. In this case, the corresponding member of
1157 every specialization of the class template is a friend of the
1158 class granting friendship.
1160 For example, given a template friend declaration
1162 template <class T> friend void A<T>::f();
1164 the member function below is considered a friend
1166 template <> struct A<int> {
1167 void f();
1168 };
1170 For this type of template friend, TEMPLATE_DEPTH below will be
1171 nonzero. To determine if DECL is a friend of FRIEND, we first
1172 check if the enclosing class is a specialization of another. */
1179 {
1180 /* Next, we check the members themselves. In order to handle
1181 a few tricky cases, such as when FRIEND_DECL's are
1183 template <class T> friend void A<T>::g(T t);
1184 template <class T> template <T t> friend void A<T>::h();
1186 and DECL's are
1188 void A<int>::g(int);
1189 template <int> void A<int>::h();
1191 we need to figure out ARGS, the template arguments from
1192 the context of DECL. This is required for template substitution
1193 of `T' in the function parameter of `g' and template parameter
1194 of `h' in the above examples. Here ARGS corresponds to `int'. */
1201 {
1203 {
1206 else
1208 current_depth++;
1209 }
1211 }
1214 {
1216 tree friend_type;
1217 tree decl_type;
1218 tree friend_args_type;
1219 tree decl_args_type;
1221 /* Make sure that both DECL and FRIEND_DECL are templates or
1222 non-templates. */
1228 {
1229 /* If both are templates, check template parameter list. */
1230 tree friend_parms
1235 friend_parms))
1239 }
1240 else
1248 /* Check if return types match. */
1252 /* Check if function parameter types match, ignoring the
1253 `this' parameter. */
1262 }
1263 else
1264 {
1265 /* DECL is a TYPE_DECL */
1269 /* Make sure that both DECL and FRIEND_DECL are templates or
1270 non-templates. */
1271 is_template
1278 {
1279 tree friend_parms;
1280 /* If both are templates, check the name of the two
1281 TEMPLATE_DECL's first because is_friend didn't. */
1286 /* Now check template parameter list. */
1287 friend_parms
1290 return comp_template_parms
1292 friend_parms);
1293 }
1294 else
1297 }
1298 }
1300 }
1302 /* Register the specialization SPEC as a specialization of TMPL with
1303 the indicated ARGS. IS_FRIEND indicates whether the specialization
1304 is actually just a friend declaration. Returns SPEC, or an
1305 equivalent prior declaration, if available. */
1307 static tree
1309 hashval_t hash)
1310 {
1311 tree fn;
1313 spec_entry elt;
1319 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1320 register it; we want the corresponding TEMPLATE_DECL instead.
1321 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1322 the more obvious `uses_template_parms (spec)' to avoid problems
1323 with default function arguments. In particular, given
1324 something like this:
1326 template <class T> void f(T t1, T t = T())
1328 the default argument expression is not substituted for in an
1329 instantiation unless and until it is actually needed. */
1333 /* We don't put these specializations in the hash table, but we might
1334 want to give an error about a mismatch. */
1336 else
1337 {
1345 slot =
1349 else
1351 }
1353 /* We can sometimes try to re-register a specialization that we've
1354 already got. In particular, regenerate_decl_from_template calls
1355 duplicate_decls which will update the specialization list. But,
1356 we'll still get called again here anyhow. It's more convenient
1357 to simply allow this than to try to prevent it. */
1361 {
1363 {
1366 {
1368 fn);
1370 }
1371 else
1372 {
1373 tree clone;
1374 /* This situation should occur only if the first
1375 specialization is an implicit instantiation, the
1376 second is an explicit specialization, and the
1377 implicit instantiation has not yet been used. That
1378 situation can occur if we have implicitly
1379 instantiated a member function and then specialized
1380 it later.
1382 We can also wind up here if a friend declaration that
1383 looked like an instantiation turns out to be a
1384 specialization:
1386 template <class T> void foo(T);
1387 class S { friend void foo<>(int) };
1388 template <> void foo(int);
1390 We transform the existing DECL in place so that any
1391 pointers to it become pointers to the updated
1392 declaration.
1394 If there was a definition for the template, but not
1395 for the specialization, we want this to look as if
1396 there were no definition, and vice versa. */
1399 /* The call to duplicate_decls will have applied
1400 [temp.expl.spec]:
1402 An explicit specialization of a function template
1403 is inline only if it is explicitly declared to be,
1404 and independently of whether its function template
1405 is.
1407 to the primary function; now copy the inline bits to
1408 the various clones. */
1410 {
1415 }
1419 }
1420 }
1422 {
1424 /* Dup decl failed, but this is a new definition. Set the
1425 line number so any errors match this new
1426 definition. */
1430 }
1431 }
1435 /* A specialization must be declared in the same namespace as the
1436 template it is specializing. */
1442 {
1450 /* TMPL is a forward declaration of a template function; keep a list
1451 of all specializations in case we need to reassign them to a friend
1452 template later in tsubst_friend_function. */
1455 }
1458 }
1460 /* Returns true iff two spec_entry nodes are equivalent. Only compares the
1461 TMPL and ARGS members, ignores SPEC. */
1463 static int
1465 {
1471 }
1473 /* Returns a hash for a template TMPL and template arguments ARGS. */
1475 static hashval_t
1477 {
1480 }
1482 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1483 ignoring SPEC. */
1485 static hashval_t
1487 {
1490 }
1492 /* Recursively calculate a hash value for a template argument ARG, for use
1493 in the hash tables of template specializations. */
1495 hashval_t
1497 {
1509 /* We can get one of these when re-hashing a previous entry in the middle
1510 of substituting into a pack expansion. Just look through it. */
1519 {
1527 {
1532 }
1554 {
1557 {
1560 }
1562 }
1566 {
1569 }
1580 val = iterative_hash_template_arg
1592 val);
1594 val);
1603 /* A lambda can't appear in a template arg, but don't crash on
1604 erroneous input. */
1616 /* Now hash operands as usual. */
1621 }
1624 {
1628 val);
1631 /* Otherwise just compare the types during lookup. */
1640 {
1645 }
1646 }
1649 }
1651 /* Unregister the specialization SPEC as a specialization of TMPL.
1652 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1653 if the SPEC was listed as a specialization of TMPL.
1655 Note that SPEC has been ggc_freed, so we can't look inside it. */
1657 bool
1659 {
1661 spec_entry elt;
1669 {
1674 }
1677 }
1679 /* Like register_specialization, but for local declarations. We are
1680 registering SPEC, an instantiation of TMPL. */
1682 static void
1684 {
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 {
1729 {
1730 /* Pick the prefix string. */
1732 {
1736 }
1740 }
1743 }
1746 {
1749 }
1750 }
1752 /* Print the list of candidate FNS in an error message. FNS can also
1753 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1755 void
1757 {
1761 }
1763 /* Returns the template (one of the functions given by TEMPLATE_ID)
1764 which can be specialized to match the indicated DECL with the
1765 explicit template args given in TEMPLATE_ID. The DECL may be
1766 NULL_TREE if none is available. In that case, the functions in
1767 TEMPLATE_ID are non-members.
1769 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1770 specialization of a member template.
1772 The TEMPLATE_COUNT is the number of references to qualifying
1773 template classes that appeared in the name of the function. See
1774 check_explicit_specialization for a more accurate description.
1776 TSK indicates what kind of template declaration (if any) is being
1777 declared. TSK_TEMPLATE indicates that the declaration given by
1778 DECL, though a FUNCTION_DECL, has template parameters, and is
1779 therefore a template function.
1781 The template args (those explicitly specified and those deduced)
1782 are output in a newly created vector *TARGS_OUT.
1784 If it is impossible to determine the result, an error message is
1785 issued. The error_mark_node is returned to indicate failure. */
1787 static tree
1789 tree decl,
1793 tmpl_spec_kind tsk)
1794 {
1795 tree fns;
1796 tree targs;
1797 tree explicit_targs;
1799 /* A TREE_LIST of templates of which DECL may be a specialization.
1800 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1801 corresponding TREE_PURPOSE is the set of template arguments that,
1802 when used to instantiate the template, would produce a function
1803 with the signature of DECL. */
1813 /* We shouldn't be specializing a member template of an
1814 unspecialized class template; we already gave an error in
1815 check_specialization_scope, now avoid crashing. */
1818 {
1821 }
1829 /* Check for baselinks. */
1834 {
1837 }
1839 /* Count the number of template headers specified for this
1840 specialization. */
1848 {
1852 {
1853 tree decl_arg_types;
1854 tree fn_arg_types;
1855 tree insttype;
1857 /* In case of explicit specialization, we need to check if
1858 the number of template headers appearing in the specialization
1859 is correct. This is usually done in check_explicit_specialization,
1860 but the check done there cannot be exhaustive when specializing
1861 member functions. Consider the following code:
1863 template <> void A<int>::f(int);
1864 template <> template <> void A<int>::f(int);
1866 Assuming that A<int> is not itself an explicit specialization
1867 already, the first line specializes "f" which is a non-template
1868 member function, whilst the second line specializes "f" which
1869 is a template member function. So both lines are syntactically
1870 correct, and check_explicit_specialization does not reject
1871 them.
1873 Here, we can do better, as we are matching the specialization
1874 against the declarations. We count the number of template
1875 headers, and we check if they match TEMPLATE_COUNT + 1
1876 (TEMPLATE_COUNT is the number of qualifying template classes,
1877 plus there must be another header for the member template
1878 itself).
1880 Notice that if header_count is zero, this is not a
1881 specialization but rather a template instantiation, so there
1882 is no check we can perform here. */
1886 /* Check that the number of template arguments at the
1887 innermost level for DECL is the same as for FN. */
1895 /* DECL might be a specialization of FN. */
1899 /* For a non-static member function, we need to make sure
1900 that the const qualification is the same. Since
1901 get_bindings does not try to merge the "this" parameter,
1902 we must do the comparison explicitly. */
1908 /* Skip the "this" parameter and, for constructors of
1909 classes with virtual bases, the VTT parameter. A
1910 full specialization of a constructor will have a VTT
1911 parameter, but a template never will. */
1912 decl_arg_types
1914 fn_arg_types
1917 /* Function templates cannot be specializations; there are
1918 no partial specializations of functions. Therefore, if
1919 the type of DECL does not match FN, there is no
1920 match. */
1922 {
1926 }
1928 /* See whether this function might be a specialization of this
1929 template. Suppress access control because we might be trying
1930 to make this specialization a friend, and we have already done
1931 access control for the declaration of the specialization. */
1937 /* We cannot deduce template arguments that when used to
1938 specialize TMPL will produce DECL. */
1941 /* Make sure that the deduced arguments actually work. */
1945 fn_arg_types
1950 /* Save this template, and the arguments deduced. */
1952 }
1954 /* FN is an ordinary member function, and we need a
1955 specialization of a member template. */
1956 ;
1958 /* We can get IDENTIFIER_NODEs here in certain erroneous
1959 cases. */
1960 ;
1962 /* This is just an ordinary non-member function. Nothing can
1963 be a specialization of that. */
1964 ;
1966 /* Cannot specialize functions that are created implicitly. */
1967 ;
1968 else
1969 {
1970 tree decl_arg_types;
1972 /* This is an ordinary member function. However, since
1973 we're here, we can assume it's enclosing class is a
1974 template class. For example,
1976 template <typename T> struct S { void f(); };
1977 template <> void S<int>::f() {}
1979 Here, S<int>::f is a non-template, but S<int> is a
1980 template class. If FN has the same type as DECL, we
1981 might be in business. */
1984 /* Its enclosing class is an explicit specialization
1985 of a template class. This is not a candidate. */
1990 /* The return types differ. */
1993 /* Adjust the type of DECL in case FN is a static member. */
2000 decl_arg_types))
2001 /* They match! */
2003 }
2004 }
2007 {
2008 /* We have:
2010 [temp.expl.spec]
2012 It is possible for a specialization with a given function
2013 signature to be instantiated from more than one function
2014 template. In such cases, explicit specification of the
2015 template arguments must be used to uniquely identify the
2016 function template specialization being specialized.
2018 Note that here, there's no suggestion that we're supposed to
2019 determine which of the candidate templates is most
2020 specialized. However, we, also have:
2022 [temp.func.order]
2024 Partial ordering of overloaded function template
2025 declarations is used in the following contexts to select
2026 the function template to which a function template
2027 specialization refers:
2029 -- when an explicit specialization refers to a function
2030 template.
2032 So, we do use the partial ordering rules, at least for now.
2033 This extension can only serve to make invalid programs valid,
2034 so it's safe. And, there is strong anecdotal evidence that
2035 the committee intended the partial ordering rules to apply;
2036 the EDG front end has that behavior, and John Spicer claims
2037 that the committee simply forgot to delete the wording in
2038 [temp.expl.spec]. */
2041 {
2044 }
2045 }
2048 {
2056 }
2060 {
2066 }
2068 /* We have one, and exactly one, match. */
2070 {
2073 /* DECL is a re-declaration or partial instantiation of a template
2074 function. */
2077 /* It was a specialization of an ordinary member function in a
2078 template class. */
2080 }
2082 /* It was a specialization of a template. */
2085 {
2090 }
2091 else
2094 }
2096 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2097 but with the default argument values filled in from those in the
2098 TMPL_TYPES. */
2100 static tree
2102 tree tmpl_types)
2103 {
2104 tree new_spec_types;
2112 /* Substitute into the rest of the list. */
2113 new_spec_types =
2117 /* Add the default argument for this parameter. */
2120 new_spec_types);
2121 }
2123 /* DECL is an explicit specialization. Replicate default arguments
2124 from the template it specializes. (That way, code like:
2126 template <class T> void f(T = 3);
2127 template <> void f(double);
2128 void g () { f (); }
2130 works, as required.) An alternative approach would be to look up
2131 the correct default arguments at the call-site, but this approach
2132 is consistent with how implicit instantiations are handled. */
2134 static void
2136 {
2137 tree tmpl;
2138 tree spec_types;
2139 tree tmpl_types;
2140 tree new_spec_types;
2141 tree old_type;
2142 tree new_type;
2143 tree t;
2148 /* See if there's anything we need to do. */
2161 {
2162 /* Remove the this pointer, but remember the object's type for
2163 CV quals. */
2169 {
2170 /* DECL may contain more parameters than TMPL due to the extra
2171 in-charge parameter in constructors and destructors. */
2174 }
2176 {
2179 }
2180 }
2182 /* Compute the merged default arguments. */
2183 new_spec_types =
2186 /* Compute the new FUNCTION_TYPE. */
2188 {
2192 new_spec_types);
2195 /* Put the in-charge parameter back. */
2198 new_spec_types);
2202 new_spec_types);
2203 }
2204 else
2206 new_spec_types);
2212 }
2214 /* Return the number of template headers we expect to see for a definition
2215 or specialization of CTYPE or one of its non-template members. */
2217 int
2219 {
2223 {
2224 /* You're supposed to have one `template <...>' for every
2225 template class, but you don't need one for a full
2226 specialization. For example:
2228 template <class T> struct S{};
2229 template <> struct S<int> { void f(); };
2230 void S<int>::f () {}
2232 is correct; there shouldn't be a `template <>' for the
2233 definition of `S<int>::f'. */
2235 /* If CTYPE does not have template information of any
2236 kind, then it is not a template, nor is it nested
2237 within a template. */
2245 }
2248 }
2250 /* Do a simple sanity check on the template headers that precede the
2251 variable declaration DECL. */
2253 void
2255 {
2262 {
2268 "members of an explicitly specialized class are defined "
2270 }
2271 }
2273 /* Check to see if the function just declared, as indicated in
2274 DECLARATOR, and in DECL, is a specialization of a function
2275 template. We may also discover that the declaration is an explicit
2276 instantiation at this point.
2278 Returns DECL, or an equivalent declaration that should be used
2279 instead if all goes well. Issues an error message if something is
2280 amiss. Returns error_mark_node if the error is not easily
2281 recoverable.
2283 FLAGS is a bitmask consisting of the following flags:
2285 2: The function has a definition.
2286 4: The function is a friend.
2288 The TEMPLATE_COUNT is the number of references to qualifying
2289 template classes that appeared in the name of the function. For
2290 example, in
2292 template <class T> struct S { void f(); };
2293 void S<int>::f();
2295 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2296 classes are not counted in the TEMPLATE_COUNT, so that in
2298 template <class T> struct S {};
2299 template <> struct S<int> { void f(); }
2300 template <> void S<int>::f();
2302 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2303 invalid; there should be no template <>.)
2305 If the function is a specialization, it is marked as such via
2306 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2307 is set up correctly, and it is added to the list of specializations
2308 for that template. */
2310 tree
2312 tree decl,
2315 {
2323 tmpl_spec_kind tsk;
2326 {
2329 else
2331 }
2332 else
2336 {
2339 {
2342 }
2344 {
2346 /* This could be something like:
2348 template <class T> void f(T);
2349 class S { friend void f<>(int); } */
2351 else
2352 {
2353 /* This case handles bogus declarations like template <>
2354 template <class T> void f<int>(); */
2357 declarator);
2359 }
2360 }
2364 /* The error has already been reported in
2365 check_specialization_scope. */
2371 /* Fall through. */
2384 decl);
2387 else
2391 /* Fall through. */
2396 else
2402 {
2403 /* This case handles bogus declarations like template <>
2404 template <class T> void f<int>(); */
2409 else
2411 declarator);
2413 }
2416 /* This is a specialization of a member template, without
2417 specialization the containing class. Something like:
2419 template <class T> struct S {
2420 template <class U> void f (U);
2421 };
2422 template <> template <class U> void S<int>::f(U) {}
2424 That's a specialization -- but of the entire template. */
2430 }
2433 {
2437 {
2441 }
2442 }
2445 {
2449 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2451 {
2452 tree fns;
2457 else
2458 {
2459 /* If there is no class context, the explicit instantiation
2460 must be at namespace scope. */
2463 /* Find the namespace binding, using the declaration
2464 context. */
2468 {
2471 }
2472 else
2473 {
2479 }
2480 }
2483 }
2489 {
2491 /* A specialization in class scope. This is invalid,
2492 but the error will already have been flagged by
2493 check_specialization_scope. */
2495 else
2496 {
2497 /* It's not valid to write an explicit instantiation in
2498 class scope, e.g.:
2500 class C { template void f(); }
2502 This case is caught by the parser. However, on
2503 something like:
2505 template class C { void f(); };
2507 (which is invalid) we can get here. The error will be
2508 issued later. */
2509 ;
2510 }
2513 }
2516 IDENTIFIER_NODE))
2517 {
2518 /* Find the list of functions in ctype that have the same
2519 name as the declared function. */
2525 {
2530 {
2531 /* From [temp.expl.spec]:
2533 If such an explicit specialization for the member
2534 of a class template names an implicitly-declared
2535 special member function (clause _special_), the
2536 program is ill-formed.
2538 Similar language is found in [temp.explicit]. */
2541 }
2544 }
2547 {
2551 }
2552 else
2553 {
2555 tree ovl;
2557 /* For a type-conversion operator, we cannot do a
2558 name-based lookup. We might be looking for `operator
2559 int' which will be a specialization of `operator T'.
2560 So, we find *all* the conversion operators, and then
2561 select from them. */
2569 {
2571 /* There are no more conversion functions. */
2574 /* Glue all these conversion functions together
2575 with those we already have. */
2578 }
2579 }
2582 {
2585 }
2586 else
2588 }
2590 /* Figure out what exactly is being specialized at this point.
2591 Note that for an explicit instantiation, even one for a
2592 member function, we cannot tell apriori whether the
2593 instantiation is for a member template, or just a member
2594 function of a template class. Even if a member template is
2595 being instantiated, the member template arguments may be
2596 elided if they can be deduced from the rest of the
2597 declaration. */
2600 member_specialization,
2601 template_count,
2602 tsk);
2605 /* We couldn't figure out what this declaration was
2606 specializing. */
2608 else
2609 {
2613 {
2614 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2615 is done by do_decl_instantiation later. */
2621 {
2622 /* If TMPL is not the most general template (for
2623 example, if TMPL is a friend template that is
2624 injected into namespace scope), then there will
2625 be too many levels of TARGS. Remove some of them
2626 here. */
2628 tree new_targs;
2635 }
2638 }
2640 /* If we thought that the DECL was a member function, but it
2641 turns out to be specializing a static member function,
2642 make DECL a static member function as well. */
2647 /* If this is a specialization of a member template of a
2648 template class, we want to return the TEMPLATE_DECL, not
2649 the specialization of it. */
2651 {
2656 {
2657 tree parm;
2661 /* We want to use the argument list specified in the
2662 definition, not in the original declaration. */
2667 }
2670 }
2672 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2675 /* Inherit default function arguments from the template
2676 DECL is specializing. */
2679 /* This specialization has the same protection as the
2680 template it specializes. */
2684 /* 7.1.1-1 [dcl.stc]
2686 A storage-class-specifier shall not be specified in an
2687 explicit specialization...
2689 The parser rejects these, so unless action is taken here,
2690 explicit function specializations will always appear with
2691 global linkage.
2693 The action recommended by the C++ CWG in response to C++
2694 defect report 605 is to make the storage class and linkage
2695 of the explicit specialization match the templated function:
2697 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2698 */
2700 {
2704 /* This specialization has the same linkage and visibility as
2705 the function template it specializes. */
2708 {
2711 }
2714 {
2717 }
2718 }
2720 /* If DECL is a friend declaration, declared using an
2721 unqualified name, the namespace associated with DECL may
2722 have been set incorrectly. For example, in:
2724 template <typename T> void f(T);
2725 namespace N {
2726 struct S { friend void f<int>(int); }
2727 }
2729 we will have set the DECL_CONTEXT for the friend
2730 declaration to N, rather than to the global namespace. */
2735 /* This is not really a declaration of a specialization.
2736 It's just the name of an instantiation. But, it's not
2737 a request for an instantiation, either. */
2740 /* This is indeed a specialization. In case of constructors
2741 and destructors, we need in-charge and not-in-charge
2742 versions in V3 ABI. */
2745 /* Register this specialization so that we can find it
2746 again. */
2748 }
2749 }
2752 }
2754 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2755 parameters. These are represented in the same format used for
2756 DECL_TEMPLATE_PARMS. */
2758 int
2760 {
2761 const_tree p1;
2762 const_tree p2;
2770 {
2782 {
2786 /* If either of the template parameters are invalid, assume
2787 they match for the sake of error recovery. */
2800 }
2801 }
2804 /* One set of parameters has more parameters lists than the
2805 other. */
2809 }
2811 /* Determine whether PARM is a parameter pack. */
2813 bool
2815 {
2816 /* Determine if we have a non-type template parameter pack. */
2823 /* If this is a list of template parameters, we could get a
2824 TYPE_DECL or a TEMPLATE_DECL. */
2828 /* Otherwise it must be a type template parameter. */
2832 }
2834 /* Determine if T is a function parameter pack. */
2836 bool
2838 {
2842 }
2844 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
2845 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
2847 tree
2849 {
2856 }
2858 /* Return true iff the function parameter PARAM_DECL was expanded
2859 from the function parameter pack PACK. */
2861 bool
2863 {
2868 /* The parameter pack and its pack arguments have the same
2869 DECL_PARM_INDEX. */
2871 }
2873 /* Determine whether ARGS describes a variadic template args list,
2874 i.e., one that is terminated by a template argument pack. */
2876 static bool
2878 {
2880 tree last_parm;
2894 }
2896 /* Generate a new name for the parameter pack name NAME (an
2897 IDENTIFIER_NODE) that incorporates its */
2899 static tree
2901 {
2902 /* Munge the name to include the parameter index. */
2903 #define NUMBUF_LEN 128
2915 }
2917 /* Return true if T is a primary function, class or alias template
2918 instantiation. */
2920 bool
2922 {
2936 }
2938 /* Return true if PARM is a template template parameter. */
2940 bool
2942 {
2944 }
2946 /* Return true iff PARM is a DECL representing a type template
2947 parameter. */
2949 bool
2951 {
2956 }
2958 /* Return the template parameters of T if T is a
2959 primary template instantiation, NULL otherwise. */
2961 tree
2963 {
2968 parms = INNERMOST_TEMPLATE_PARMS
2972 }
2974 /* Return the template parameters of the LEVELth level from the full list
2975 of template parameters PARMS. */
2977 tree
2979 {
2980 tree p;
2991 }
2993 /* Returns the template arguments of T if T is a template instantiation,
2994 NULL otherwise. */
2996 tree
2998 {
3006 }
3008 /* Return the argument pack elements of T if T is a template argument pack,
3009 NULL otherwise. */
3011 tree
3013 {
3019 }
3021 /* Structure used to track the progress of find_parameter_packs_r. */
3022 struct find_parameter_pack_data
3023 {
3024 /* TREE_LIST that will contain all of the parameter packs found by
3025 the traversal. */
3028 /* Set of AST nodes that have been visited by the traversal. */
3030 };
3032 /* Identifies all of the argument packs that occur in a template
3033 argument and appends them to the TREE_LIST inside DATA, which is a
3034 find_parameter_pack_data structure. This is a subroutine of
3035 make_pack_expansion and uses_parameter_packs. */
3036 static tree
3038 {
3044 /* Handle type aliases/typedefs. */
3049 {
3056 }
3058 /* Identify whether this is a parameter pack or not. */
3060 {
3075 {
3076 /* We don't want to walk into the type of a PARM_DECL,
3077 because we don't want to see the type parameter pack. */
3080 }
3087 /* Not a parameter pack. */
3089 }
3092 {
3093 /* Add this parameter pack to the list. */
3095 }
3101 /* This switch statement will return immediately if we don't find a
3102 parameter pack. */
3104 {
3109 /* Check the template itself. */
3112 /* Check the template arguments. */
3128 /* Fall through. */
3170 }
3173 }
3175 /* Determines if the expression or type T uses any parameter packs. */
3176 bool
3178 {
3186 }
3188 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3189 representation a base-class initializer into a parameter pack
3190 expansion. If all goes well, the resulting node will be an
3191 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3192 respectively. */
3193 tree
3195 {
3196 tree result;
3205 {
3206 /* The only time we will see a TREE_LIST here is for a base
3207 class initializer. In this case, the TREE_PURPOSE will be a
3208 _TYPE node (representing the base class expansion we're
3209 initializing) and the TREE_VALUE will be a TREE_LIST
3210 containing the initialization arguments.
3212 The resulting expansion looks somewhat different from most
3213 expansions. Rather than returning just one _EXPANSION, we
3214 return a TREE_LIST whose TREE_PURPOSE is a
3215 TYPE_PACK_EXPANSION containing the bases that will be
3216 initialized. The TREE_VALUE will be identical to the
3217 original TREE_VALUE, which is a list of arguments that will
3218 be passed to each base. We do not introduce any new pack
3219 expansion nodes into the TREE_VALUE (although it is possible
3220 that some already exist), because the TREE_PURPOSE and
3221 TREE_VALUE all need to be expanded together with the same
3222 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3223 resulting TREE_PURPOSE will mention the parameter packs in
3224 both the bases and the arguments to the bases. */
3225 tree purpose;
3226 tree value;
3229 /* Determine which parameter packs will be used by the base
3230 class expansion. */
3237 {
3241 }
3244 {
3245 /* Collect the sets of parameter packs used in each of the
3246 initialization arguments. */
3248 {
3249 /* Determine which parameter packs will be expanded in this
3250 argument. */
3253 }
3254 }
3258 /* Create the pack expansion type for the base type. */
3263 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3264 they will rarely be compared to anything. */
3268 }
3273 /* Build the PACK_EXPANSION_* node. */
3274 result = for_types
3279 {
3280 /* Propagate type and const-expression information. */
3283 }
3284 else
3285 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3286 they will rarely be compared to anything. */
3289 /* Determine which parameter packs will be expanded. */
3295 /* Make sure we found some parameter packs. */
3297 {
3300 else
3303 }
3309 }
3311 /* Checks T for any "bare" parameter packs, which have not yet been
3312 expanded, and issues an error if any are found. This operation can
3313 only be done on full expressions or types (e.g., an expression
3314 statement, "if" condition, etc.), because we could have expressions like:
3316 foo(f(g(h(args)))...)
3318 where "args" is a parameter pack. check_for_bare_parameter_packs
3319 should not be called for the subexpressions args, h(args),
3320 g(h(args)), or f(g(h(args))), because we would produce erroneous
3321 error messages.
3323 Returns TRUE and emits an error if there were bare parameter packs,
3324 returns FALSE otherwise. */
3325 bool
3327 {
3343 {
3346 {
3355 else
3360 else
3364 }
3367 }
3370 }
3372 /* Expand any parameter packs that occur in the template arguments in
3373 ARGS. */
3374 tree
3376 {
3382 /* First, determine if we need to expand anything, and the number of
3383 slots we'll need. */
3385 {
3390 {
3394 else
3396 }
3397 else
3398 {
3400 num_result_args++;
3401 }
3402 }
3404 /* If no expansion is necessary, we're done. */
3408 /* Expand arguments. */
3411 non_default_args_count =
3414 {
3417 {
3424 }
3425 else
3426 {
3429 }
3430 }
3434 }
3436 /* Checks if DECL shadows a template parameter.
3438 [temp.local]: A template-parameter shall not be redeclared within its
3439 scope (including nested scopes).
3441 Emits an error and returns TRUE if the DECL shadows a parameter,
3442 returns FALSE otherwise. */
3444 bool
3446 {
3447 tree olddecl;
3449 /* If we're not in a template, we can't possibly shadow a template
3450 parameter. */
3454 /* Figure out what we're shadowing. */
3459 /* If there's no previous binding for this name, we're not shadowing
3460 anything, let alone a template parameter. */
3464 /* If we're not shadowing a template parameter, we're done. Note
3465 that OLDDECL might be an OVERLOAD (or perhaps even an
3466 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3467 node. */
3471 /* We check for decl != olddecl to avoid bogus errors for using a
3472 name inside a class. We check TPFI to avoid duplicate errors for
3473 inline member templates. */
3481 }
3483 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3484 ORIG_LEVEL, DECL, and TYPE. */
3486 static tree
3490 tree decl,
3491 tree type)
3492 {
3503 }
3505 /* Find the canonical type parameter for the given template type
3506 parameter. Returns the canonical type parameter, which may be TYPE
3507 if no such parameter existed. */
3509 static tree
3511 {
3512 tree list;
3526 else
3527 {
3532 }
3533 }
3535 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3536 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3537 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3538 new one is created. */
3540 static tree
3542 tsubst_flags_t complain)
3543 {
3548 {
3567 /* Template template parameters need this. */
3572 }
3575 }
3577 /* Process information from new template parameter PARM and append it
3578 to the LIST being built. This new parameter is a non-type
3579 parameter iff IS_NON_TYPE is true. This new parameter is a
3580 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3581 is in PARM_LOC. NUM_TEMPLATE_PARMS is the size of the template
3582 parameter list PARM belongs to. This is used used to create a
3583 proper canonical type for the type of PARM that is to be created,
3584 iff PARM is a type. If the size is not known, this parameter shall
3585 be set to 0. */
3587 tree
3590 {
3592 tree defval;
3593 tree err_parm_list;
3600 {
3604 {
3608 else
3610 }
3613 }
3614 else
3618 {
3624 {
3628 }
3629 else
3630 {
3631 /* [temp.param]
3633 The top-level cv-qualifiers on the template-parameter are
3634 ignored when determining its type. */
3637 {
3641 }
3644 {
3645 /* This template parameter is not a parameter pack, but it
3646 should be. Complain about "bare" parameter packs. */
3649 /* Recover by calling this a parameter pack. */
3651 }
3652 }
3654 /* A template parameter is not modifiable. */
3663 processing_template_decl,
3668 }
3669 else
3670 {
3671 tree t;
3675 {
3677 /* This is for distinguishing between real templates and template
3678 template parameters */
3682 }
3683 else
3684 {
3686 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3689 }
3696 processing_template_decl,
3700 }
3706 }
3708 /* The end of a template parameter list has been reached. Process the
3709 tree list into a parameter vector, converting each parameter into a more
3710 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3711 as PARM_DECLs. */
3713 tree
3715 {
3720 current_template_parms
3725 {
3729 }
3734 }
3736 /* end_template_decl is called after a template declaration is seen. */
3738 void
3740 {
3746 /* This matches the pushlevel in begin_template_parm_list. */
3751 }
3753 /* Takes a TREE_LIST representing a template parameter and convert it
3754 into an argument suitable to be passed to the type substitution
3755 functions. Note that If the TREE_LIST contains an error_mark
3756 node, the returned argument is error_mark_node. */
3758 static tree
3760 {
3773 {
3777 {
3778 /* Turn this argument into a TYPE_ARGUMENT_PACK
3779 with a single element, which expands T. */
3781 #ifdef ENABLE_CHECKING
3782 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3784 #endif
3789 }
3790 }
3791 else
3792 {
3796 {
3797 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3798 with a single element, which expands T. */
3801 #ifdef ENABLE_CHECKING
3802 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3804 #endif
3810 }
3811 }
3813 }
3815 /* This function returns TRUE if PARM_PACK is a template parameter
3816 pack and if ARG_PACK is what template_parm_to_arg returned when
3817 passed PARM_PACK. */
3819 static bool
3821 {
3822 /* For clarity in the comments below let's use the representation
3823 argument_pack<elements>' to denote an argument pack and its
3824 elements.
3826 In the 'if' block below, we want to detect cases where
3827 ARG_PACK is argument_pack<PARM_PACK...>. I.e, we want to
3828 check if ARG_PACK is an argument pack which sole element is
3829 the expansion of PARM_PACK. That argument pack is typically
3830 created by template_parm_to_arg when passed a parameter
3831 pack. */
3836 {
3841 /* The argument pack that the parameter maps to is just an
3842 expansion of the parameter itself, such as one would
3843 find in the implicit typedef of a class inside the
3844 class itself. Consider this parameter "unsubstituted",
3845 so that we will maintain the outer pack expansion. */
3847 }
3849 }
3851 /* Given a set of template parameters, return them as a set of template
3852 arguments. The template parameters are represented as a TREE_VEC, in
3853 the form documented in cp-tree.h for template arguments. */
3855 static tree
3857 {
3858 tree header;
3863 /* If there is only one level of template parameters, we do not
3864 create a TREE_VEC of TREE_VECs. Instead, we return a single
3865 TREE_VEC containing the arguments. */
3870 {
3878 #ifdef ENABLE_CHECKING
3880 #endif
3884 else
3886 }
3889 /* This can happen for template parms of a template template
3890 parameter, e.g:
3892 template<template<class T, class U> class TT> struct S;
3894 Consider the level of the parms of TT; T and U both have
3895 level 2; TT has no template parm of level 1. So in this case
3896 the first element of full_template_args is NULL_TREE. If we
3897 leave it like this TMPL_ARG_DEPTH on args returns 1 instead
3898 of 2. This will make tsubst wrongly consider that T and U
3899 have level 1. Instead, let's create a dummy vector as the
3900 first element of full_template_args so that TMPL_ARG_DEPTH
3901 returns the correct depth for args. */
3904 }
3906 /* Within the declaration of a template, return the currently active
3907 template parameters as an argument TREE_VEC. */
3909 static tree
3911 {
3913 }
3915 /* Update the declared TYPE by doing any lookups which were thought to be
3916 dependent, but are not now that we know the SCOPE of the declarator. */
3918 tree
3920 {
3931 /* Don't bother building up the args in this case. */
3933 {
3934 /* tsubst in the args corresponding to the template parameters,
3935 including auto if present. Most things will be unchanged, but
3936 make_typename_type and tsubst_qualified_id will resolve
3937 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
3940 tree pushed;
3942 {
3946 }
3951 }
3957 {
3960 else
3962 }
3964 }
3966 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
3967 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
3968 a member template. Used by push_template_decl below. */
3970 static tree
3972 {
3980 }
3982 struct template_parm_data
3983 {
3984 /* The level of the template parameters we are currently
3985 processing. */
3988 /* The index of the specialization argument we are currently
3989 processing. */
3992 /* An array whose size is the number of template parameters. The
3993 elements are nonzero if the parameter has been used in any one
3994 of the arguments processed so far. */
3997 /* An array whose size is the number of template arguments. The
3998 elements are nonzero if the argument makes use of template
3999 parameters of this level. */
4001 };
4003 /* Subroutine of push_template_decl used to see if each template
4004 parameter in a partial specialization is used in the explicit
4005 argument list. If T is of the LEVEL given in DATA (which is
4006 treated as a template_parm_data*), then DATA->PARMS is marked
4007 appropriately. */
4009 static int
4011 {
4017 {
4020 }
4021 else
4022 {
4025 }
4028 {
4031 }
4033 /* Return zero so that for_each_template_parm will continue the
4034 traversal of the tree; we want to mark *every* template parm. */
4036 }
4038 /* Process the partial specialization DECL. */
4040 static tree
4042 {
4048 tree inner_parms;
4049 tree inst;
4062 /* We check that each of the template parameters given in the
4063 partial specialization is used in the argument list to the
4064 specialization. For example:
4066 template <class T> struct S;
4067 template <class T> struct S<T*>;
4069 The second declaration is OK because `T*' uses the template
4070 parameter T, whereas
4072 template <class T> struct S<int>;
4074 is no good. Even trickier is:
4076 template <class T>
4077 struct S1
4078 {
4079 template <class U>
4080 struct S2;
4081 template <class U>
4082 struct S2<T>;
4083 };
4085 The S2<T> declaration is actually invalid; it is a
4086 full-specialization. Of course,
4088 template <class U>
4089 struct S2<T (*)(U)>;
4091 or some such would have been OK. */
4099 {
4104 NULL,
4106 }
4109 {
4110 /* One of the template parms was not used in the
4111 specialization. */
4113 {
4116 }
4119 }
4124 /* [temp.class.spec]
4126 The argument list of the specialization shall not be identical to
4127 the implicit argument list of the primary template. */
4134 /* A partial specialization that replaces multiple parameters of the
4135 primary template with a pack expansion is less specialized for those
4136 parameters. */
4138 {
4140 "primary template because it replaces multiple parameters "
4144 }
4146 /* [temp.class.spec]
4148 A partially specialized non-type argument expression shall not
4149 involve template parameters of the partial specialization except
4150 when the argument expression is a simple identifier.
4152 The type of a template parameter corresponding to a specialized
4153 non-type argument shall not be dependent on a parameter of the
4154 specialization.
4156 Also, we verify that pack expansions only occur at the
4157 end of the argument list. */
4161 {
4168 {
4169 /* Extract the arguments from the argument pack. We'll be
4170 iterating over these in the following loop. */
4173 }
4176 {
4178 /* Get the Jth argument in the parameter pack. */
4182 {
4183 /* Pack expansions must come at the end of the
4184 argument list. */
4187 {
4191 else
4194 }
4195 }
4198 /* We only care about the pattern. */
4204 /* This next line is the `argument expression is not just a
4205 simple identifier' condition and also the `specialized
4206 non-type argument' bit. */
4208 {
4212 arg);
4213 else
4214 {
4215 /* Look at the corresponding template parameter,
4216 marking which template parameters its type depends
4217 upon. */
4221 {
4222 /* We haven't yet initialized TPD2. Do so now. */
4224 /* The number of parameters here is the number in the
4225 main template, which, as checked in the assertion
4226 above, is NARGS. */
4230 }
4232 /* Mark the template parameters. But this time, we're
4233 looking for the template parameters of the main
4234 template, not in the specialization. */
4241 NULL,
4245 {
4246 /* The type depended on some template parameters.
4247 If they are fully specialized in the
4248 specialization, that's OK. */
4257 "type %qT of template argument %qE depends "
4259 "type %qT of template argument %qE depends "
4261 type,
4262 arg);
4263 }
4264 }
4265 }
4266 }
4267 }
4269 /* We should only get here once. */
4279 {
4283 {
4287 "partial specialization of %qT after instantiation "
4289 }
4290 }
4293 }
4295 /* Check that a template declaration's use of default arguments and
4296 parameter packs is not invalid. Here, PARMS are the template
4297 parameters. IS_PRIMARY is true if DECL is the thing declared by
4298 a primary template. IS_PARTIAL is true if DECL is a partial
4299 specialization.
4301 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4302 declaration (but not a definition); 1 indicates a declaration, 2
4303 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4304 emitted for extraneous default arguments.
4306 Returns TRUE if there were no errors found, FALSE otherwise. */
4308 bool
4311 {
4314 tree parm_level;
4317 /* [temp.param]
4319 A default template-argument shall not be specified in a
4320 function template declaration or a function template definition, nor
4321 in the template-parameter-list of the definition of a member of a
4322 class template. */
4325 /* You can't have a function template declaration in a local
4326 scope, nor you can you define a member of a class template in a
4327 local scope. */
4334 /* If this is either a friend defined in the scope of the class
4335 or a member function. */
4341 /* And, if it was a member function, it really was defined in
4342 the scope of the class. */
4345 /* We already checked these parameters when the template was
4346 declared, so there's no need to do it again now. This function
4347 was defined in class scope, but we're processing it's body now
4348 that the class is complete. */
4351 /* Core issue 226 (C++0x only): the following only applies to class
4352 templates. */
4355 {
4356 /* [temp.param]
4358 If a template-parameter has a default template-argument, all
4359 subsequent template-parameters shall have a default
4360 template-argument supplied. */
4362 {
4369 {
4379 {
4381 /* For better subsequent error-recovery, we indicate that
4382 there should have been a default argument. */
4385 }
4387 && !is_friend_decl
4388 /* Don't complain about an enclosing partial
4389 specialization. */
4394 {
4395 /* A primary class template can only have one
4396 parameter pack, at the end of the template
4397 parameter list. */
4402 else
4410 }
4411 }
4412 }
4413 }
4416 || is_partial
4417 || !is_primary
4419 /* For an ordinary class template, default template arguments are
4420 allowed at the innermost level, e.g.:
4421 template <class T = int>
4422 struct S {};
4423 but, in a partial specialization, they're not allowed even
4424 there, as we have in [temp.class.spec]:
4426 The template parameter list of a specialization shall not
4427 contain default template argument values.
4429 So, for a partial specialization, or for a function template
4430 (in C++98/C++03), we look at all of them. */
4431 ;
4432 else
4433 /* But, for a primary class template that is not a partial
4434 specialization we look at all template parameters except the
4435 innermost ones. */
4438 /* Figure out what error message to issue. */
4451 else
4455 /* If we're inside a class definition, there's no need to
4456 examine the parameters to the class itself. On the one
4457 hand, they will be checked when the class is defined, and,
4458 on the other, default arguments are valid in things like:
4459 template <class T = double>
4460 struct S { template <class U> void f(U); };
4461 Here the default argument for `S' has no bearing on the
4462 declaration of `f'. */
4464 else
4465 /* Check everything. */
4471 {
4478 {
4483 {
4485 {
4492 }
4494 /* Clear out the default argument so that we are not
4495 confused later. */
4497 }
4498 }
4500 /* At this point, if we're still interested in issuing messages,
4501 they must apply to classes surrounding the object declared. */
4505 }
4508 }
4510 /* Worker for push_template_decl_real, called via
4511 for_each_template_parm. DATA is really an int, indicating the
4512 level of the parameters we are interested in. If T is a template
4513 parameter of that level, return nonzero. */
4515 static int
4517 {
4523 else
4526 }
4528 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
4529 parameters given by current_template_args, or reuses a
4530 previously existing one, if appropriate. Returns the DECL, or an
4531 equivalent one, if it is replaced via a call to duplicate_decls.
4533 If IS_FRIEND is true, DECL is a friend declaration. */
4535 tree
4537 {
4538 tree tmpl;
4539 tree args;
4540 tree info;
4541 tree ctx;
4545 /* True if the template is a member template, in the sense of
4546 [temp.mem]. */
4552 /* See if this is a partial specialization. */
4561 /* For a friend, we want the context of the friend function, not
4562 the type of which it is a friend. */
4566 /* In the case of a virtual function, we want the class in which
4567 it is defined. */
4569 else
4570 /* Otherwise, if we're currently defining some class, the DECL
4571 is assumed to be a member of the class. */
4580 /* See if this is a primary template. */
4582 /* A friend template that specifies a class context, i.e.
4583 template <typename T> friend void A<T>::f();
4584 is not primary. */
4586 else
4590 {
4595 {
4598 }
4600 {
4602 {
4603 /* [temp.mem]
4605 A destructor shall not be a member template. */
4608 }
4615 {
4616 /* [basic.stc.dynamic.allocation]
4618 An allocation function can be a function
4619 template. ... Template allocation functions shall
4620 have two or more parameters. */
4623 }
4624 }
4630 /* alias-declaration */
4632 else
4633 {
4636 }
4637 }
4639 /* Check to see that the rules regarding the use of default
4640 arguments are not being violated. */
4644 /* Ensure that there are no parameter packs in the type of this
4645 declaration that have not been expanded. */
4647 {
4648 /* Check each of the arguments individually to see if there are
4649 any bare parameter packs. */
4655 {
4658 {
4659 /* This is a PARM_DECL that contains unexpanded parameter
4660 packs. We have already complained about this in the
4661 check_for_bare_parameter_packs call, so just replace
4662 these types with ERROR_MARK_NODE. */
4665 }
4669 }
4671 /* Check for bare parameter packs in the return type and the
4672 exception specifiers. */
4674 /* Errors were already issued, set return type to int
4675 as the frontend doesn't expect error_mark_node as
4676 the return type. */
4680 }
4685 {
4688 }
4699 {
4704 /* If DECL is a TYPE_DECL for a class-template, then there won't
4705 be DECL_LANG_SPECIFIC. The information equivalent to
4706 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
4710 {
4711 /* Since a template declaration already existed for this
4712 class-type, we must be redeclaring it here. Make sure
4713 that the redeclaration is valid. */
4715 current_template_parms);
4716 /* We don't need to create a new TEMPLATE_DECL; just use the
4717 one we already had. */
4719 }
4720 else
4721 {
4723 member_template_p);
4728 {
4729 /* A specialization of a member template of a template
4730 class. */
4734 }
4735 }
4736 }
4737 else
4738 {
4744 {
4747 }
4755 {
4756 tree new_tmpl;
4758 /* The declaration is a specialization of a member
4759 template, declared outside the class. Therefore, the
4760 innermost template arguments will be NULL, so we
4761 replace them with the arguments determined by the
4762 earlier call to check_explicit_specialization. */
4765 new_tmpl
4767 member_template_p);
4777 args,
4780 }
4782 /* Make sure the template headers we got make sense. */
4787 {
4790 }
4791 else
4793 {
4798 {
4802 else
4807 }
4812 /* Can happen in erroneous input. */
4814 else
4818 }
4820 /* Check that the parms are used in the appropriate qualifying scopes
4821 in the declarator. */
4825 {
4831 /* Avoid crash in import_export_decl. */
4834 }
4835 }
4840 /* Push template declarations for global functions and types. Note
4841 that we do not try to push a global template friend declared in a
4842 template class; such a thing may well depend on the template
4843 parameters of the class. */
4846 {
4851 /* Hide template friend classes that haven't been declared yet. */
4853 {
4856 }
4857 }
4860 {
4866 {
4869 /* It is a conversion operator. See if the type converted to
4870 depends on innermost template operands. */
4873 depth))
4875 }
4877 /* Give template template parms a DECL_CONTEXT of the template
4878 for which they are a parameter. */
4881 {
4885 }
4886 }
4888 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
4889 back to its most general template. If TMPL is a specialization,
4890 ARGS may only have the innermost set of arguments. Add the missing
4891 argument levels if necessary. */
4899 else
4900 {
4905 }
4908 }
4910 tree
4912 {
4914 }
4916 /* FN is an inheriting constructor that inherits from the constructor
4917 template INHERITED; turn FN into a constructor template with a matching
4918 template header. */
4920 tree
4922 {
4923 tree inner_parms
4926 tree parms
4937 }
4939 /* Called when a class template TYPE is redeclared with the indicated
4940 template PARMS, e.g.:
4942 template <class T> struct S;
4943 template <class T> struct S {}; */
4945 bool
4947 {
4948 tree tmpl;
4949 tree tmpl_parms;
4953 {
4956 }
4960 /* The type is nested in some template class. Nothing to worry
4961 about here; there are no new template parameters for the nested
4962 type. */
4966 {
4968 tmpl);
4970 }
4976 {
4986 }
4989 {
4990 tree tmpl_parm;
4991 tree parm;
4992 tree tmpl_default;
4993 tree parm_default;
5007 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5008 TEMPLATE_DECL. */
5018 {
5022 }
5025 {
5026 /* We have in [temp.param]:
5028 A template-parameter may not be given default arguments
5029 by two different declarations in the same scope. */
5034 }
5037 /* Update the previous template parameters (which are the ones
5038 that will really count) with the new default value. */
5041 /* Update the new parameters, too; they'll be used as the
5042 parameters for any members. */
5044 }
5047 }
5049 /* Simplify EXPR if it is a non-dependent expression. Returns the
5050 (possibly simplified) expression. */
5052 tree
5054 {
5058 /* If we're in a template, but EXPR isn't value dependent, simplify
5059 it. We're supposed to treat:
5061 template <typename T> void f(T[1 + 1]);
5062 template <typename T> void f(T[2]);
5064 as two declarations of the same function, for example. */
5069 {
5070 HOST_WIDE_INT saved_processing_template_decl;
5076 complain,
5081 }
5083 }
5085 tree
5087 {
5089 }
5091 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5092 template declaration, or a TYPE_DECL for an alias declaration. */
5094 bool
5096 {
5104 }
5106 /* Return TRUE iff is a specialization of an alias template. */
5108 bool
5110 {
5118 }
5120 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5121 must be a function or a pointer-to-function type, as specified
5122 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5123 and check that the resulting function has external linkage. */
5125 static tree
5127 {
5130 linkage_kind linkage;
5142 /* [temp.arg.nontype]/1
5144 A template-argument for a non-type, non-template template-parameter
5145 shall be one of:
5146 [...]
5147 -- the address of an object or function with external [C++11: or
5148 internal] linkage. */
5151 {
5156 else
5161 }
5164 }
5166 /* Subroutine of convert_nontype_argument.
5167 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5168 Emit an error otherwise. */
5170 static bool
5172 tsubst_flags_t complain)
5173 {
5180 {
5184 }
5186 }
5188 /* Returns TRUE iff the address of OP is value-dependent.
5190 14.6.2.4 [temp.dep.temp]:
5191 A non-integral non-type template-argument is dependent if its type is
5192 dependent or it has either of the following forms
5193 qualified-id
5194 & qualified-id
5195 and contains a nested-name-specifier which specifies a class-name that
5196 names a dependent type.
5198 We generalize this to just say that the address of a member of a
5199 dependent class is value-dependent; the above doesn't cover the
5200 address of a static data member named with an unqualified-id. */
5202 static bool
5204 {
5205 /* We could use get_inner_reference here, but there's no need;
5206 this is only relevant for template non-type arguments, which
5207 can only be expressed as &id-expression. */
5209 {
5213 }
5216 }
5218 /* The next set of functions are used for providing helpful explanatory
5219 diagnostics for failed overload resolution. Their messages should be
5220 indented by two spaces for consistency with the messages in
5221 call.c */
5223 static int
5225 {
5227 }
5229 static int
5231 {
5236 }
5238 static int
5240 {
5242 }
5244 static int
5246 {
5252 }
5254 static int
5256 {
5260 }
5262 static int
5264 {
5267 " template parameter %qD is not a parameter pack, but "
5271 }
5273 static int
5275 {
5278 " template argument %qE does not match "
5282 }
5284 static int
5286 {
5290 }
5292 static int
5294 {
5300 }
5302 static int
5304 {
5306 {
5311 else
5313 " deduced conflicting values for non-type parameter "
5315 }
5317 }
5319 static int
5321 {
5324 " variable-sized array type %qT is not "
5326 arg);
5328 }
5330 static int
5332 {
5336 arg);
5338 }
5340 static int
5342 {
5349 }
5351 static int
5353 {
5355 }
5357 static int
5359 {
5361 }
5363 static int
5366 {
5371 }
5373 static int
5376 {
5379 {
5387 }
5389 }
5391 static int
5393 {
5396 " template parameters of a template template argument are "
5399 }
5401 static int
5403 {
5409 }
5411 static int
5413 {
5418 }
5420 static int
5422 {
5426 arg);
5428 }
5430 /* Attempt to convert the non-type template parameter EXPR to the
5431 indicated TYPE. If the conversion is successful, return the
5432 converted value. If the conversion is unsuccessful, return
5433 NULL_TREE if we issued an error message, or error_mark_node if we
5434 did not. We issue error messages for out-and-out bad template
5435 parameters, but not simply because the conversion failed, since we
5436 might be just trying to do argument deduction. Both TYPE and EXPR
5437 must be non-dependent.
5439 The conversion follows the special rules described in
5440 [temp.arg.nontype], and it is much more strict than an implicit
5441 conversion.
5443 This function is called twice for each template argument (see
5444 lookup_template_class for a more accurate description of this
5445 problem). This means that we need to handle expressions which
5446 are not valid in a C++ source, but can be created from the
5447 first call (for instance, casts to perform conversions). These
5448 hacks can go away after we fix the double coercion problem. */
5450 static tree
5452 {
5453 tree expr_type;
5455 /* Detect immediately string literals as invalid non-type argument.
5456 This special-case is not needed for correctness (we would easily
5457 catch this later), but only to provide better diagnostic for this
5458 common user mistake. As suggested by DR 100, we do not mention
5459 linkage issues in the diagnostic as this is not the point. */
5460 /* FIXME we're making this OK. */
5462 {
5468 }
5470 /* Add the ADDR_EXPR now for the benefit of
5471 value_dependent_expression_p. */
5474 {
5478 }
5480 /* If we are in a template, EXPR may be non-dependent, but still
5481 have a syntactic, rather than semantic, form. For example, EXPR
5482 might be a SCOPE_REF, rather than the VAR_DECL to which the
5483 SCOPE_REF refers. Preserving the qualifying scope is necessary
5484 so that access checking can be performed when the template is
5485 instantiated -- but here we need the resolved form so that we can
5486 convert the argument. */
5497 else
5500 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
5501 to a non-type argument of "nullptr". */
5505 /* In C++11, integral or enumeration non-type template arguments can be
5506 arbitrary constant expressions. Pointer and pointer to
5507 member arguments can be general constant expressions that evaluate
5508 to a null value, but otherwise still need to be of a specific form. */
5510 {
5512 /* A PTRMEM_CST is already constant, and a valid template
5513 argument for a parameter of pointer to member type, we just want
5514 to leave it in that form rather than lower it to a
5519 {
5524 }
5525 }
5527 /* HACK: Due to double coercion, we can get a
5528 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5529 which is the tree that we built on the first call (see
5530 below when coercing to reference to object or to reference to
5531 function). We just strip everything and get to the arg.
5532 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5533 for examples. */
5535 {
5541 {
5542 /* ??? Maybe we could use convert_from_reference here, but we
5543 would need to relax its constraints because the NOP_EXPR
5544 could actually change the type to something more cv-qualified,
5545 and this is not folded by convert_from_reference. */
5556 }
5557 }
5559 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5560 parameter is a pointer to object, through decay and
5561 qualification conversion. Let's strip everything. */
5563 {
5567 /* Skip the ADDR_EXPR only if it is part of the decay for
5568 an array. Otherwise, it is part of the original argument
5569 in the source code. */
5573 }
5575 /* [temp.arg.nontype]/5, bullet 1
5577 For a non-type template-parameter of integral or enumeration type,
5578 integral promotions (_conv.prom_) and integral conversions
5579 (_conv.integral_) are applied. */
5581 {
5590 /* Notice that there are constant expressions like '4 % 0' which
5591 do not fold into integer constants. */
5593 {
5595 {
5606 /* else cxx_constant_value complained but gave us
5607 a real constant, so go ahead. */
5609 }
5610 else
5612 }
5613 }
5614 /* [temp.arg.nontype]/5, bullet 2
5616 For a non-type template-parameter of type pointer to object,
5617 qualification conversions (_conv.qual_) and the array-to-pointer
5618 conversion (_conv.array_) are applied. */
5620 {
5621 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
5623 A template-argument for a non-type, non-template template-parameter
5624 shall be one of: [...]
5626 -- the name of a non-type template-parameter;
5627 -- the address of an object or function with external linkage, [...]
5628 expressed as "& id-expression" where the & is optional if the name
5629 refers to a function or array, or if the corresponding
5630 template-parameter is a reference.
5632 Here, we do not care about functions, as they are invalid anyway
5633 for a parameter of type pointer-to-object. */
5636 /* Non-type template parameters are OK. */
5637 ;
5642 {
5644 {
5646 "because %qD is a variable, not the address of "
5650 }
5651 /* Other values, like integer constants, might be valid
5652 non-type arguments of some other type. */
5654 }
5655 else
5656 {
5657 tree decl;
5662 {
5667 }
5669 {
5674 }
5676 {
5681 }
5682 }
5691 }
5692 /* [temp.arg.nontype]/5, bullet 3
5694 For a non-type template-parameter of type reference to object, no
5695 conversions apply. The type referred to by the reference may be more
5696 cv-qualified than the (otherwise identical) type of the
5697 template-argument. The template-parameter is bound directly to the
5698 template-argument, which must be an lvalue. */
5700 {
5702 expr_type))
5706 {
5710 }
5713 {
5717 }
5719 /* [temp.arg.nontype]/1
5721 A template-argument for a non-type, non-template template-parameter
5722 shall be one of: [...]
5724 -- the address of an object or function with external linkage. */
5727 {
5730 {
5732 "because a reference variable does not have a constant "
5735 }
5736 }
5739 {
5744 }
5747 {
5752 }
5755 }
5756 /* [temp.arg.nontype]/5, bullet 4
5758 For a non-type template-parameter of type pointer to function, only
5759 the function-to-pointer conversion (_conv.func_) is applied. If the
5760 template-argument represents a set of overloaded functions (or a
5761 pointer to such), the matching function is selected from the set
5762 (_over.over_). */
5764 {
5765 /* If the argument is a template-id, we might not have enough
5766 context information to decay the pointer. */
5768 {
5772 }
5775 /* Null pointer values are OK in C++11. */
5783 {
5787 }
5788 }
5789 /* [temp.arg.nontype]/5, bullet 5
5791 For a non-type template-parameter of type reference to function, no
5792 conversions apply. If the template-argument represents a set of
5793 overloaded functions, the matching function is selected from the set
5794 (_over.over_). */
5796 {
5798 {
5803 }
5810 }
5811 /* [temp.arg.nontype]/5, bullet 6
5813 For a non-type template-parameter of type pointer to member function,
5814 no conversions apply. If the template-argument represents a set of
5815 overloaded member functions, the matching member function is selected
5816 from the set (_over.over_). */
5818 {
5823 /* [temp.arg.nontype] bullet 1 says the pointer to member
5824 expression must be a pointer-to-member constant. */
5828 /* There is no way to disable standard conversions in
5829 resolve_address_of_overloaded_function (called by
5830 instantiate_type). It is possible that the call succeeded by
5831 converting &B::I to &D::I (where B is a base of D), so we need
5832 to reject this conversion here.
5834 Actually, even if there was a way to disable standard conversions,
5835 it would still be better to reject them here so that we can
5836 provide a superior diagnostic. */
5838 {
5842 /* If we are just one standard conversion off, explain. */
5847 }
5848 }
5849 /* [temp.arg.nontype]/5, bullet 7
5851 For a non-type template-parameter of type pointer to data member,
5852 qualification conversions (_conv.qual_) are applied. */
5854 {
5855 /* [temp.arg.nontype] bullet 1 says the pointer to member
5856 expression must be a pointer-to-member constant. */
5863 }
5865 {
5867 {
5871 }
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 =
6238 {
6240 {
6244 }
6247 "to refer to a type member of a template parameter, "
6252 typename_type,
6253 complain);
6256 }
6258 {
6260 {
6262 {
6272 else
6274 }
6275 }
6277 }
6279 {
6281 {
6287 else
6289 }
6291 }
6294 {
6296 {
6300 /* The number of argument required is not known yet.
6301 Just accept it for now. */
6303 else
6304 {
6306 tree argparm;
6312 args))
6313 {
6316 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6317 TEMPLATE_DECL. */
6319 {
6324 }
6325 }
6326 else
6327 {
6329 {
6335 }
6338 }
6339 }
6340 }
6341 else
6343 /* We only form one instance of each template specialization.
6344 Therefore, if we use a non-canonical variant (i.e., a
6345 typedef), any future messages referring to the type will use
6346 the typedef, which is confusing if those future uses do not
6347 themselves also use the typedef. */
6350 }
6351 else
6352 {
6359 {
6362 else
6363 {
6364 /* Not sure if this is reachable, but it doesn't hurt
6365 to be robust. */
6368 }
6369 }
6371 /* We used to call digest_init here. However, digest_init
6372 will report errors, which we don't want when complain
6373 is zero. More importantly, digest_init will try too
6374 hard to convert things: for example, `0' should not be
6375 converted to pointer type at this point according to
6376 the standard. Accepting this is not merely an
6377 extension, since deciding whether or not these
6378 conversions can occur is part of determining which
6379 function template to call, or whether a given explicit
6380 argument specification is valid. */
6382 else
6391 {
6392 /* Strip typedefs from the SCOPE_REF. */
6395 complain);
6398 }
6399 }
6402 }
6404 /* Coerces the remaining template arguments in INNER_ARGS (from
6405 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6406 Returns the coerced argument pack. PARM_IDX is the position of this
6407 parameter in the template parameter list. ARGS is the original
6408 template argument list. */
6409 static tree
6412 tree args,
6413 tree inner_args,
6415 tree new_args,
6417 tree in_decl,
6418 tsubst_flags_t complain)
6419 {
6422 tree packed_args;
6423 tree argument_pack;
6433 {
6434 /* When the template parameter is a non-type template
6435 parameter pack whose type uses parameter packs, we need
6436 to look at each of the template arguments
6437 separately. Build a vector of the types for these
6438 non-type template parameters in PACKED_TYPES. */
6439 tree expansion
6447 /* Check that we have the right number of arguments. */
6451 {
6452 int needed_parms
6457 }
6459 /* If we aren't able to check the actual arguments now
6460 (because they haven't been expanded yet), we can at least
6461 verify that all of the types used for the non-type
6462 template parameter pack are, in fact, valid for non-type
6463 template parameters. */
6466 {
6469 {
6473 }
6474 }
6475 }
6477 /* Convert the remaining arguments, which will be a part of the
6478 parameter pack "parm". */
6480 {
6485 {
6486 /* When we have a vector of types (corresponding to the
6487 non-type template parameter pack that uses parameter
6488 packs in its type, as mention above), and the
6489 argument is not an expansion (which expands to a
6490 currently unknown number of arguments), clone the
6491 parm and give it the next type in PACKED_TYPES. */
6495 }
6498 {
6501 }
6502 else
6505 in_decl);
6509 }
6514 else
6515 {
6520 }
6523 #ifdef ENABLE_CHECKING
6526 #endif
6528 }
6530 /* Returns true if the template argument vector ARGS contains
6531 any pack expansions, false otherwise. */
6533 static bool
6535 {
6542 }
6544 /* Convert all template arguments to their appropriate types, and
6545 return a vector containing the innermost resulting template
6546 arguments. If any error occurs, return error_mark_node. Error and
6547 warning messages are issued under control of COMPLAIN.
6549 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6550 for arguments not specified in ARGS. Otherwise, if
6551 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
6552 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
6553 USE_DEFAULT_ARGS is false, then all arguments must be specified in
6554 ARGS. */
6556 static tree
6558 tree args,
6559 tree in_decl,
6560 tsubst_flags_t complain,
6563 {
6565 tree inner_args;
6566 tree new_args;
6567 tree new_inner_args;
6571 /* When used as a boolean value, indicates whether this is a
6572 variadic template parameter list. Since it's an int, we can also
6573 subtract it from nparms to get the number of non-variadic
6574 parameters. */
6583 /* Determine if there are any parameter packs. */
6585 {
6591 }
6594 /* If there are no parameters that follow a parameter pack, we need to
6595 expand any argument packs so that we can deduce a parameter pack from
6596 some non-packed args followed by an argument pack, as in variadic85.C.
6597 If there are such parameters, we need to leave argument packs intact
6598 so the arguments are assigned properly. This can happen when dealing
6599 with a nested class inside a partial specialization of a class
6600 template, as in variadic92.C, or when deducing a template parameter pack
6601 from a sub-declarator, as in variadic114.C. */
6608 && require_all_args
6610 && (!use_default_args
6613 {
6615 {
6617 {
6621 }
6622 else
6628 }
6631 }
6633 /* We need to evaluate the template arguments, even though this
6634 template-id may be nested within a "sizeof". */
6642 {
6643 tree arg;
6644 tree parm;
6646 /* Get the Ith template parameter. */
6650 {
6653 }
6655 /* Calculate the next argument. */
6658 else
6663 {
6664 /* All remaining arguments will be placed in the
6665 template parameter pack PARM. */
6671 /* Store this argument. */
6673 lost++;
6676 /* We are done with all of the arguments. */
6680 }
6682 {
6684 {
6685 /* We don't know how many args we have yet, just
6686 use the unconverted ones for now. */
6689 }
6690 }
6692 {
6693 /* There must be a default arg in this case. */
6696 /* The position of the first default template argument,
6697 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
6698 Record that. */
6701 }
6702 else
6706 {
6709 }
6711 /* This only occurs if there was an error in the template
6712 parameter list itself (which we would already have
6713 reported) that we are trying to recover from, e.g., a class
6714 template with a parameter list such as
6715 template<typename..., typename>. */
6717 else
6723 lost++;
6725 }
6732 #ifdef ENABLE_CHECKING
6736 #endif
6739 }
6741 /* Returns 1 if template args OT and NT are equivalent. */
6743 static int
6745 {
6752 /* For member templates */
6761 {
6778 }
6780 {
6781 /* We get here probably because we are in the middle of substituting
6782 into the pattern of a pack expansion. In that case the
6783 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
6784 interested in. So we want to use the initial pack argument for
6785 the comparison. */
6790 }
6795 else
6797 }
6799 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
6800 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
6801 NEWARG_PTR with the offending arguments if they are non-NULL. */
6803 static int
6806 {
6819 {
6824 {
6830 }
6831 }
6833 }
6835 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
6836 of template arguments. Returns 0 otherwise. */
6838 int
6840 {
6842 }
6844 static void
6846 {
6856 /* We are called both from instantiate_decl, where we've already had a
6857 tinst_level pushed, and instantiate_template, where we haven't.
6858 Compensate. */
6869 else
6878 }
6881 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
6882 ARGLIST. Valid choices for FNS are given in the cp-tree.def
6883 documentation for TEMPLATE_ID_EXPR. */
6885 tree
6887 {
6888 tree type;
6896 {
6899 }
6902 {
6904 unknown_type_node,
6906 arglist);
6908 }
6915 }
6917 /* Within the scope of a template class S<T>, the name S gets bound
6918 (in build_self_reference) to a TYPE_DECL for the class, not a
6919 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
6920 or one of its enclosing classes, and that type is a template,
6921 return the associated TEMPLATE_DECL. Otherwise, the original
6922 DECL is returned.
6924 Also handle the case when DECL is a TREE_LIST of ambiguous
6925 injected-class-names from different bases. */
6927 tree
6929 {
6933 /* DR 176: A lookup that finds an injected-class-name (10.2
6934 [class.member.lookup]) can result in an ambiguity in certain cases
6935 (for example, if it is found in more than one base class). If all of
6936 the injected-class-names that are found refer to specializations of
6937 the same class template, and if the name is followed by a
6938 template-argument-list, the reference refers to the class template
6939 itself and not a specialization thereof, and is not ambiguous. */
6941 {
6944 {
6950 }
6953 else
6955 }
6961 }
6963 /* Given an IDENTIFIER_NODE (type TEMPLATE_DECL) and a chain of
6964 parameters, find the desired type.
6966 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
6968 IN_DECL, if non-NULL, is the template declaration we are trying to
6969 instantiate.
6971 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
6972 the class we are looking up.
6974 Issue error and warning messages under control of COMPLAIN.
6976 If the template class is really a local class in a template
6977 function, then the FUNCTION_CONTEXT is the function in which it is
6978 being instantiated.
6980 ??? Note that this function is currently called *twice* for each
6981 template-id: the first time from the parser, while creating the
6982 incomplete type (finish_template_type), and the second type during the
6983 real instantiation (instantiate_template_class). This is surely something
6984 that we want to avoid. It also causes some problems with argument
6985 coercion (see convert_nontype_argument for more information on this). */
6987 static tree
6990 {
6992 tree t;
6995 spec_entry elt;
6996 hashval_t hash;
6999 {
7003 else
7004 {
7011 }
7014 }
7016 {
7019 /* If we are declaring a constructor, say A<T>::A<T>, we will get
7020 an implicit typename for the second A. Deal with it. */
7025 {
7028 }
7029 }
7032 {
7035 }
7039 {
7043 }
7045 /* Issue an error message if we didn't find a template. */
7047 {
7051 }
7054 /* Make sure it's a user visible template, if it was named by
7055 the user. */
7058 {
7060 {
7064 }
7066 }
7071 {
7072 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7073 template arguments */
7075 tree parm;
7076 tree arglist2;
7077 tree outer;
7081 /* Consider an example where a template template parameter declared as
7083 template <class T, class U = std::allocator<T> > class TT
7085 The template parameter level of T and U are one level larger than
7086 of TT. To proper process the default argument of U, say when an
7087 instantiation `TT<int>' is seen, we need to build the full
7088 arguments containing {int} as the innermost level. Outer levels,
7089 available when not appearing as default template argument, can be
7090 obtained from the arguments of the enclosing template.
7092 Suppose that TT is later substituted with std::vector. The above
7093 instantiation is `TT<int, std::allocator<T> >' with TT at
7094 level 1, and T at level 2, while the template arguments at level 1
7095 becomes {std::vector} and the inner level 2 is {int}. */
7101 /* This is an argument of the current template, so we haven't set
7102 DECL_CONTEXT yet. */
7109 complain,
7119 }
7120 else
7121 {
7123 tree gen_tmpl;
7124 tree type_decl;
7132 /* An error occured while building the template TEMPL, and a
7133 diagnostic has most certainly been emitted for that
7134 already. Let's propagate that error. */
7143 {
7144 /* We've been given an incomplete set of template arguments.
7145 For example, given:
7147 template <class T> struct S1 {
7148 template <class U> struct S2 {};
7149 template <class U> struct S2<U*> {};
7150 };
7152 we will be called with an ARGLIST of `U*', but the
7153 TEMPLATE will be `template <class T> template
7154 <class U> struct S1<T>::S2'. We must fill in the missing
7155 arguments. */
7156 arglist
7158 arglist);
7160 }
7162 /* Now we should have enough arguments. */
7165 /* From here on, we're only interested in the most general
7166 template. */
7168 /* Calculate the BOUND_ARGS. These will be the args that are
7169 actually tsubst'd into the definition to create the
7170 instantiation. */
7172 {
7173 /* We have multiple levels of arguments to coerce, at once. */
7183 {
7184 tree a;
7188 complain,
7191 else
7192 /* Outer levels should have already been coerced. */
7195 /* Don't process further if one of the levels fails. */
7197 {
7198 /* Restore the ARGLIST to its full size. */
7201 }
7205 /* We temporarily reduce the length of the ARGLIST so
7206 that coerce_template_parms will see only the arguments
7207 corresponding to the template parameters it is
7208 examining. */
7210 }
7212 /* Restore the ARGLIST to its full size. */
7216 }
7217 else
7218 arglist
7221 gen_tmpl,
7222 complain,
7227 /* We were unable to bind the arguments. */
7230 /* In the scope of a template class, explicit references to the
7231 template class refer to the type of the template, not any
7232 instantiation of it. For example, in:
7234 template <class T> class C { void f(C<T>); }
7236 the `C<T>' is just the same as `C'. Outside of the
7237 class, however, such a reference is an instantiation. */
7241 /* comp_template_args is expensive, check it last. */
7243 arglist))
7246 /* If we already have this specialization, return it. */
7258 /* If the deduced arguments are invalid, then the binding
7259 failed. */
7263 complain))
7270 {
7275 }
7285 /* Create the type. */
7287 {
7289 {
7295 }
7296 else
7297 {
7298 /* We don't want to call start_enum for this type, since
7299 the values for the enumeration constants may involve
7300 template parameters. And, no one should be interested
7301 in the enumeration constants for such a type. */
7304 }
7308 }
7310 {
7311 /* The user referred to a specialization of an alias
7312 template represented by GEN_TMPL.
7314 [temp.alias]/2 says:
7316 When a template-id refers to the specialization of an
7317 alias template, it is equivalent to the associated
7318 type obtained by substitution of its
7319 template-arguments for the template-parameters in the
7320 type-id of the alias template. */
7323 /* Note that the call above (by indirectly calling
7324 register_specialization in tsubst_decl) registers the
7325 TYPE_DECL representing the specialization of the alias
7326 template. So next time someone substitutes ARGLIST for
7327 the template parms into the alias template (GEN_TMPL),
7328 she'll get that TYPE_DECL back. */
7332 }
7334 {
7341 /* A local class. Make sure the decl gets registered properly. */
7346 /* This instantiation is another name for the primary
7347 template type. Set the TYPE_CANONICAL field
7348 appropriately. */
7351 /* Some of the template arguments require structural
7352 equality testing, so this template class requires
7353 structural equality testing. */
7355 }
7356 else
7359 /* If we called start_enum or pushtag above, this information
7360 will already be set up. */
7362 {
7369 }
7370 else
7374 {
7380 {
7383 }
7384 }
7386 /* Let's consider the explicit specialization of a member
7387 of a class template specialization that is implicitely instantiated,
7388 e.g.:
7389 template<class T>
7390 struct S
7391 {
7392 template<class U> struct M {}; //#0
7393 };
7395 template<>
7396 template<>
7397 struct S<int>::M<char> //#1
7398 {
7399 int i;
7400 };
7401 [temp.expl.spec]/4 says this is valid.
7403 In this case, when we write:
7404 S<int>::M<char> m;
7406 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
7407 the one of #0.
7409 When we encounter #1, we want to store the partial instantiation
7410 of M (template<class T> S<int>::M<T>) in it's CLASSTYPE_TI_TEMPLATE.
7412 For all cases other than this "explicit specialization of member of a
7413 class template", we just want to store the most general template into
7414 the CLASSTYPE_TI_TEMPLATE of M.
7416 This case of "explicit specialization of member of a class template"
7417 only happens when:
7418 1/ the enclosing class is an instantiation of, and therefore not
7419 the same as, the context of the most general template, and
7420 2/ we aren't looking at the partial instantiation itself, i.e.
7421 the innermost arguments are not the same as the innermost parms of
7422 the most general template.
7424 So it's only when 1/ and 2/ happens that we want to use the partial
7425 instantiation of the member template in lieu of its most general
7426 template. */
7430 /* the enclosing class must be an instantiation... */
7433 {
7434 tree partial_inst_args;
7437 partial_inst_args =
7443 use_partial_inst_tmpl =
7444 /*...and we must not be looking at the partial instantiation
7445 itself. */
7447 partial_inst_args);
7448 }
7451 /* This case is easy; there are no member templates involved. */
7453 else
7454 {
7455 /* This is a full instantiation of a member template. Find
7456 the partial instantiation of which this is an instance. */
7458 /* Temporarily reduce by one the number of levels in the ARGLIST
7459 so as to avoid comparing the last set of arguments. */
7463 /* FOUND is either a proper class type, or an alias
7464 template specialization. In the later case, it's a
7465 TYPE_DECL, resulting from the substituting of arguments
7466 for parameters in the TYPE_DECL of the alias template
7467 done earlier. So be careful while getting the template
7468 of FOUND. */
7472 }
7483 /* Note this use of the partial instantiation so we can check it
7484 later in maybe_process_partial_specialization. */
7490 /* Now that the type has been registered on the instantiations
7491 list, we set up the enumerators. Because the enumeration
7492 constants may involve the enumeration type itself, we make
7493 sure to register the type first, and then create the
7494 constants. That way, doing tsubst_expr for the enumeration
7495 constants won't result in recursive calls here; we'll find
7496 the instantiation and exit above. */
7500 /* If the type makes use of template parameters, the
7501 code that generates debugging information will crash. */
7504 /* Possibly limit visibility based on template args. */
7509 }
7510 }
7512 /* Wrapper for lookup_template_class_1. */
7514 tree
7517 {
7518 tree ret;
7524 }
7525 \f
7526 struct pair_fn_data
7527 {
7528 tree_fn_t fn;
7530 /* True when we should also visit template parameters that occur in
7531 non-deduced contexts. */
7534 };
7536 /* Called from for_each_template_parm via walk_tree. */
7538 static tree
7540 {
7553 {
7557 /* Fall through. */
7580 /* Since we're not going to walk subtrees, we have to do this
7581 explicitly here. */
7585 /* Fall through. */
7588 /* Check the return type. */
7593 /* Check the parameter types. Since default arguments are not
7594 instantiated until they are needed, the TYPE_ARG_TYPES may
7595 contain expressions that involve template parameters. But,
7596 no-one should be looking at them yet. And, once they're
7597 instantiated, they don't contain template parameters, so
7598 there's no point in looking at them then, either. */
7599 {
7600 tree parm;
7607 /* Since we've already handled the TYPE_ARG_TYPES, we don't
7608 want walk_tree walking into them itself. */
7610 }
7628 /* Fall through. */
7644 /* Record template parameters such as `T' inside `TT<T>'. */
7648 /* Fall through. */
7660 /* A template template parameter is encountered. */
7666 /* Already substituted template template parameter */
7689 /* If there's no type, then this thing must be some expression
7690 involving template parameters. */
7712 }
7714 /* We didn't find any template parameters we liked. */
7716 }
7718 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
7719 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
7720 call FN with the parameter and the DATA.
7721 If FN returns nonzero, the iteration is terminated, and
7722 for_each_template_parm returns 1. Otherwise, the iteration
7723 continues. If FN never returns a nonzero value, the value
7724 returned by for_each_template_parm is 0. If FN is NULL, it is
7725 considered to be the function which always returns 1.
7727 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
7728 parameters that occur in non-deduced contexts. When false, only
7729 visits those template parameters that can be deduced. */
7731 static int
7735 {
7739 /* Set up. */
7744 /* Walk the tree. (Conceptually, we would like to walk without
7745 duplicates, but for_each_template_parm_r recursively calls
7746 for_each_template_parm, so we would need to reorganize a fair
7747 bit to use walk_tree_without_duplicates, so we keep our own
7748 visited list.) */
7751 else
7754 for_each_template_parm_r,
7758 /* Clean up. */
7760 {
7763 }
7766 }
7768 /* Returns true if T depends on any template parameter. */
7770 int
7772 {
7799 else
7800 {
7803 }
7808 }
7810 /* Returns true iff current_function_decl is an incompletely instantiated
7811 template. Useful instead of processing_template_decl because the latter
7812 is set to 0 during fold_non_dependent_expr. */
7814 bool
7816 {
7825 }
7827 /* Returns true if T depends on any template parameter with level LEVEL. */
7829 int
7831 {
7834 }
7836 /* Returns TRUE iff INST is an instantiation we don't need to do in an
7837 ill-formed translation unit, i.e. a variable or function that isn't
7838 usable in a constant expression. */
7842 {
7846 }
7848 /* Returns TRUE iff we should refuse to instantiate DECL because it's
7849 neglectable and instantiated from within an erroneous instantiation. */
7851 static bool
7853 {
7864 }
7872 /* We're starting to instantiate D; record the template instantiation context
7873 for diagnostics and to restore it later. */
7875 int
7877 {
7881 {
7887 else
7895 }
7897 /* If the current instantiation caused problems, don't let it instantiate
7898 anything else. Do allow deduction substitution and decls usable in
7899 constant expressions. */
7916 }
7918 /* We're done instantiating this template; return to the instantiation
7919 context. */
7921 void
7923 {
7924 /* Restore the filename and line number stashed away when we started
7925 this instantiation. */
7929 }
7931 /* We're instantiating a deferred template; restore the template
7932 instantiation context in which the instantiation was requested, which
7933 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
7935 static tree
7937 {
7949 }
7951 /* Returns the TINST_LEVEL which gives the original instantiation
7952 context. */
7956 {
7962 }
7964 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
7965 vector of template arguments, as for tsubst.
7967 Returns an appropriate tsubst'd friend declaration. */
7969 static tree
7971 {
7972 tree new_friend;
7977 /* This was a friend declared with an explicit template
7978 argument list, e.g.:
7980 friend void f<>(T);
7982 to indicate that f was a template instantiation, not a new
7983 function declaration. Now, we have to figure out what
7984 instantiation of what template. */
7985 {
7987 tree new_args;
7988 tree tmpl;
7991 /* Friend functions are looked up in the containing namespace scope.
7992 We must enter that scope, to avoid finding member functions of the
7993 current class with same name. */
8008 tsk_none);
8010 }
8014 /* The NEW_FRIEND will look like an instantiation, to the
8015 compiler, but is not an instantiation from the point of view of
8016 the language. For example, we might have had:
8018 template <class T> struct S {
8019 template <class U> friend void f(T, U);
8020 };
8022 Then, in S<int>, template <class U> void f(int, U) is not an
8023 instantiation of anything. */
8029 {
8033 }
8035 /* The mangled name for the NEW_FRIEND is incorrect. The function
8036 is not a template instantiation and should not be mangled like
8037 one. Therefore, we forget the mangling here; we'll recompute it
8038 later if we need it. */
8040 {
8043 }
8046 {
8047 tree old_decl;
8048 tree new_friend_template_info;
8049 tree new_friend_result_template_info;
8050 tree ns;
8053 /* We must save some information from NEW_FRIEND before calling
8054 duplicate decls since that function will free NEW_FRIEND if
8055 possible. */
8057 new_friend_is_defn =
8062 {
8063 /* This declaration is a `primary' template. */
8066 new_friend_result_template_info
8068 }
8069 else
8072 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8076 /* Inside pushdecl_namespace_level, we will push into the
8077 current namespace. However, the friend function should go
8078 into the namespace of the template. */
8088 {
8089 /* This new friend declaration matched an existing
8090 declaration. For example, given:
8092 template <class T> void f(T);
8093 template <class U> class C {
8094 template <class T> friend void f(T) {}
8095 };
8097 the friend declaration actually provides the definition
8098 of `f', once C has been instantiated for some type. So,
8099 old_decl will be the out-of-class template declaration,
8100 while new_friend is the in-class definition.
8102 But, if `f' was called before this point, the
8103 instantiation of `f' will have DECL_TI_ARGS corresponding
8104 to `T' but not to `U', references to which might appear
8105 in the definition of `f'. Previously, the most general
8106 template for an instantiation of `f' was the out-of-class
8107 version; now it is the in-class version. Therefore, we
8108 run through all specialization of `f', adding to their
8109 DECL_TI_ARGS appropriately. In particular, they need a
8110 new set of outer arguments, corresponding to the
8111 arguments for this class instantiation.
8113 The same situation can arise with something like this:
8115 friend void f(int);
8116 template <class T> class C {
8117 friend void f(T) {}
8118 };
8120 when `C<int>' is instantiated. Now, `f(int)' is defined
8121 in the class. */
8124 /* On the other hand, if the in-class declaration does
8125 *not* provide a definition, then we don't want to alter
8126 existing definitions. We can just leave everything
8127 alone. */
8128 ;
8129 else
8130 {
8134 /* Overwrite whatever template info was there before, if
8135 any, with the new template information pertaining to
8136 the declaration. */
8140 {
8141 /* We should have called reregister_specialization in
8142 duplicate_decls. */
8147 /* Instantiate it if the global has already been used. */
8151 }
8152 else
8153 {
8154 tree t;
8156 /* Indicate that the old function template is a partial
8157 instantiation. */
8165 /* Reassign any specializations already in the hash table
8166 to the new more general template, and add the
8167 additional template args. */
8171 {
8173 spec_entry elt;
8185 register_specialization
8188 }
8190 }
8191 }
8193 /* The information from NEW_FRIEND has been merged into OLD_DECL
8194 by duplicate_decls. */
8196 }
8197 }
8198 else
8199 {
8203 /* In the code
8204 template <class T> class C {
8205 template <class U> friend void C1<U>::f (); // case 1
8206 friend void C2<T>::f (); // case 2
8207 };
8208 we only need to make sure CONTEXT is a complete type for
8209 case 2. To distinguish between the two cases, we note that
8210 CONTEXT of case 1 remains dependent type after tsubst while
8211 this isn't true for case 2. */
8221 {
8222 /* Check to see that the declaration is really present, and,
8223 possibly obtain an improved declaration. */
8229 }
8230 }
8233 }
8235 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8236 template arguments, as for tsubst.
8238 Returns an appropriate tsubst'd friend type or error_mark_node on
8239 failure. */
8241 static tree
8243 {
8244 tree friend_type;
8245 tree tmpl;
8246 tree context;
8249 {
8252 }
8257 {
8260 else
8262 }
8264 /* Look for a class template declaration. We look for hidden names
8265 because two friend declarations of the same template are the
8266 same. For example, in:
8268 struct A {
8269 template <typename> friend class F;
8270 };
8271 template <typename> struct B {
8272 template <typename> friend class F;
8273 };
8275 both F templates are the same. */
8279 /* But, if we don't find one, it might be because we're in a
8280 situation like this:
8282 template <class T>
8283 struct S {
8284 template <class U>
8285 friend struct S;
8286 };
8288 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8289 for `S<int>', not the TEMPLATE_DECL. */
8291 {
8294 }
8297 {
8298 /* The friend template has already been declared. Just
8299 check to see that the declarations match, and install any new
8300 default parameters. We must tsubst the default parameters,
8301 of course. We only need the innermost template parameters
8302 because that is all that redeclare_class_template will look
8303 at. */
8306 {
8307 tree parms;
8308 location_t saved_input_location;
8317 }
8320 }
8321 else
8322 {
8323 /* The friend template has not already been declared. In this
8324 case, the instantiation of the template class will cause the
8325 injection of this template into the global scope. */
8330 /* The new TMPL is not an instantiation of anything, so we
8331 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
8332 the new type because that is supposed to be the corresponding
8333 template decl, i.e., TMPL. */
8340 /* Inject this template into the global scope. */
8342 }
8345 {
8348 else
8350 }
8353 }
8355 /* Returns zero if TYPE cannot be completed later due to circularity.
8356 Otherwise returns one. */
8358 static int
8360 {
8370 else
8372 }
8374 /* Apply any attributes which had to be deferred until instantiation
8375 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
8376 ARGS, COMPLAIN, IN_DECL are as tsubst. */
8378 static void
8381 {
8383 tree t;
8388 {
8392 }
8395 {
8399 }
8400 else
8404 {
8409 {
8412 {
8415 /* If the first attribute argument is an identifier, don't
8416 pass it through tsubst. Attributes like mode, format,
8417 cleanup and several target specific attributes expect it
8418 unmodified. */
8424 {
8425 tree chain
8427 in_decl,
8432 chain);
8433 }
8434 else
8440 }
8441 else
8443 }
8446 }
8447 }
8449 /* Perform (or defer) access check for typedefs that were referenced
8450 from within the template TMPL code.
8451 This is a subroutine of instantiate_decl and instantiate_class_template.
8452 TMPL is the template to consider and TARGS is the list of arguments of
8453 that template. */
8455 static void
8457 {
8458 location_t saved_location;
8469 {
8481 /* Make access check error messages point to the location
8482 of the use of the typedef. */
8486 tf_warning_or_error);
8487 }
8489 }
8491 static tree
8493 {
8495 tree typedecl;
8496 tree pbinfo;
8497 tree base_list;
8499 tree fn_context;
8508 /* Figure out which template is being instantiated. */
8512 /* Determine what specialization of the original template to
8513 instantiate. */
8516 {
8519 }
8521 {
8522 /* This TYPE is actually an instantiation of a partial
8523 specialization. We replace the innermost set of ARGS with
8524 the arguments appropriate for substitution. For example,
8525 given:
8527 template <class T> struct S {};
8528 template <class T> struct S<T*> {};
8530 and supposing that we are instantiating S<int*>, ARGS will
8531 presently be {int*} -- but we need {int}. */
8534 }
8535 else
8536 {
8539 }
8541 /* If the template we're instantiating is incomplete, then clearly
8542 there's nothing we can do. */
8546 /* If we've recursively instantiated too many templates, stop. */
8550 /* Now we're really doing the instantiation. Mark the type as in
8551 the process of being defined. */
8554 /* We may be in the middle of deferred access check. Disable
8555 it now. */
8561 /* Use #pragma pack from the template context. */
8567 /* Set the input location to the most specialized template definition.
8568 This is needed if tsubsting causes an error. */
8580 {
8583 /* Adjust visibility for template arguments. */
8585 }
8590 /* We should never instantiate a nested class before its enclosing
8591 class; we need to look up the nested class by name before we can
8592 instantiate it, and that lookup should instantiate the enclosing
8593 class. */
8599 {
8600 tree pbase_binfo;
8601 tree pushed_scope;
8604 /* We must enter the scope containing the type, as that is where
8605 the accessibility of types named in dependent bases are
8606 looked up from. */
8609 /* Substitute into each of the bases to determine the actual
8610 basetypes. */
8612 {
8613 tree base;
8619 {
8620 expanded_bases =
8627 }
8630 {
8632 /* Extract the already-expanded base class. */
8634 else
8635 /* Substitute to figure out the base class. */
8637 NULL_TREE);
8645 }
8646 }
8648 /* The list is now in reverse order; correct that. */
8653 }
8654 /* Now call xref_basetypes to set up all the base-class
8655 information. */
8663 /* Now that our base classes are set up, enter the scope of the
8664 class, so that name lookups into base classes, etc. will work
8665 correctly. This is precisely analogous to what we do in
8666 begin_class_definition when defining an ordinary non-template
8667 class, except we also need to push the enclosing classes. */
8670 /* Now members are processed in the order of declaration. */
8673 {
8677 {
8679 {
8680 /* Build new CLASSTYPE_NESTED_UTDS. */
8682 tree newtag;
8688 /* If the member is a class template, then -- even after
8689 substitution -- there may be dependent types in the
8690 template argument list for the class. We increment
8691 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
8692 that function will assume that no types are dependent
8693 when outside of a template. */
8703 {
8707 /* Unfortunately, lookup_template_class sets
8708 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
8709 instantiation (i.e., for the type of a member
8710 template class nested within a template class.)
8711 This behavior is required for
8712 maybe_process_partial_specialization to work
8713 correctly, but is not accurate in this case;
8714 the TAG is not an instantiation of anything.
8715 (The corresponding TEMPLATE_DECL is an
8716 instantiation, but the TYPE is not.) */
8719 /* Now, we call pushtag to put this NEWTAG into the scope of
8720 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
8721 pushtag calling push_template_decl. We don't have to do
8722 this for enums because it will already have been done in
8723 tsubst_enum. */
8727 }
8728 }
8731 {
8732 /* Build new TYPE_METHODS. */
8733 tree r;
8742 /* Instantiate members marked with attribute used. */
8745 }
8746 else
8747 {
8748 /* Build new TYPE_FIELDS. */
8750 {
8751 tree condition;
8754 condition =
8764 }
8766 {
8767 tree r;
8769 /* The file and line for this declaration, to
8770 assist in error message reporting. Since we
8771 called push_tinst_level above, we don't need to
8772 restore these. */
8781 {
8782 /* In [temp.inst]:
8784 [t]he initialization (and any associated
8785 side-effects) of a static data member does
8786 not occur unless the static data member is
8787 itself used in a way that requires the
8788 definition of the static data member to
8789 exist.
8791 Therefore, we do not substitute into the
8792 initialized for the static data member here. */
8793 finish_static_data_member_decl
8799 /* Instantiate members marked with attribute used. */
8802 }
8804 {
8805 /* Determine whether R has a valid type and can be
8806 completed later. If R is invalid, then it is
8807 replaced by error_mark_node so that it will not be
8808 added to TYPE_FIELDS. */
8814 {
8817 }
8818 }
8820 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
8821 such a thing will already have been added to the field
8822 list by tsubst_enum in finish_member_declaration in the
8823 CLASSTYPE_NESTED_UTDS case above. */
8827 {
8830 }
8831 }
8832 }
8833 }
8834 else
8835 {
8838 {
8839 /* Build new CLASSTYPE_FRIEND_CLASSES. */
8845 {
8846 /* template <class T> friend class C; */
8849 }
8851 {
8852 /* template <class T> friend class C::D; */
8858 }
8861 {
8862 /* This could be either
8864 friend class T::C;
8866 when dependent_type_p is false or
8868 template <class U> friend class T::C;
8870 otherwise. */
8873 /* Bump processing_template_decl for correct
8874 dependent_type_p calculation. */
8879 }
8882 {
8883 /* friend class C;
8885 where C hasn't been declared yet. Let's lookup name
8886 from namespace scope directly, bypassing any name that
8887 come from dependent base class. */
8890 /* The call to xref_tag_from_type does injection for friend
8891 classes. */
8893 friend_type =
8897 }
8899 /* friend class C<T>; */
8902 /* Otherwise it's
8904 friend class C;
8906 where C is already declared or
8908 friend class C<int>;
8910 We don't have to do anything in these cases. */
8913 /* Trick make_friend_class into realizing that the friend
8914 we're adding is a template, not an ordinary class. It's
8915 important that we use make_friend_class since it will
8916 perform some error-checking and output cross-reference
8917 information. */
8925 }
8926 else
8927 {
8928 /* Build new DECL_FRIENDLIST. */
8929 tree r;
8931 /* The file and line for this declaration, to
8932 assist in error message reporting. Since we
8933 called push_tinst_level above, we don't need to
8934 restore these. */
8938 {
8941 }
8946 {
8949 }
8950 }
8951 }
8952 }
8955 {
8958 {
8967 }
8968 else
8970 }
8972 /* Set the file and line number information to whatever is given for
8973 the class itself. This puts error messages involving generated
8974 implicit functions at a predictable point, and the same point
8975 that would be used for non-template classes. */
8982 /* We don't instantiate default arguments for member functions. 14.7.1:
8984 The implicit instantiation of a class template specialization causes
8985 the implicit instantiation of the declarations, but not of the
8986 definitions or default arguments, of the class member functions,
8987 member classes, static data members and member templates.... */
8989 /* Some typedefs referenced from within the template code need to be access
8990 checked at template instantiation time, i.e now. These types were
8991 added to the template at parsing time. Let's get those and perform
8992 the access checks then. */
9002 /* The vtable for a template class can be emitted in any translation
9003 unit in which the class is instantiated. When there is no key
9004 method, however, finish_struct_1 will already have added TYPE to
9005 the keyed_classes list. */
9010 }
9012 /* Wrapper for instantiate_class_template_1. */
9014 tree
9016 {
9017 tree ret;
9022 }
9024 static tree
9026 {
9027 tree r;
9033 else
9034 {
9041 /* Preserve the raw-reference nature of T. */
9045 }
9047 }
9049 /* Given a function parameter pack TMPL_PARM and some function parameters
9050 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
9051 and set *SPEC_P to point at the next point in the list. */
9053 static tree
9055 {
9056 /* Collect all of the extra "packed" parameters into an
9057 argument pack. */
9058 tree parmvec;
9059 tree parmtypevec;
9070 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
9075 {
9078 }
9080 /* Build the argument packs. */
9087 }
9089 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9090 NONTYPE_ARGUMENT_PACK. */
9092 static tree
9094 {
9096 }
9098 /* Substitute ARGS into T, which is an pack expansion
9099 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
9100 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
9101 (if only a partial substitution could be performed) or
9102 ERROR_MARK_NODE if there was an error. */
9103 tree
9105 tree in_decl)
9106 {
9107 tree pattern;
9113 tree result;
9121 /* Add in any args remembered from an earlier partial instantiation. */
9126 /* Determine the argument packs that will instantiate the parameter
9127 packs used in the expansion expression. While we're at it,
9128 compute the number of arguments to be expanded and make sure it
9129 is consistent. */
9132 {
9139 {
9143 else
9146 }
9148 {
9151 else
9152 {
9153 /* We can't rely on local_specializations for a parameter
9154 name used later in a function declaration (such as in a
9155 late-specified return type). Even if it exists, it might
9156 have the wrong value for a recursive call. Just make a
9157 dummy decl, since it's only used for its type. */
9160 /* Partial instantiation of the parm_pack, we can't build
9161 up an argument pack yet. */
9163 else
9166 }
9167 }
9168 else
9169 {
9175 }
9182 /* This can only happen if we forget to expand an argument
9183 pack somewhere else. Just return an error, silently. */
9184 {
9188 }
9191 /* The argument pack that the parameter maps to is just an
9192 expansion of the parameter itself, such as one would find
9193 in the implicit typedef of a class inside the class itself.
9194 Consider this parameter "unsubstituted", so that we will
9195 maintain the outer pack expansion. */
9199 {
9203 /* Don't bother trying to do a partial substitution with
9204 incomplete packs; we'll try again after deduction. */
9211 {
9217 pattern);
9218 else
9221 pattern);
9223 }
9229 else
9232 /* Keep track of the parameter packs and their corresponding
9233 argument packs. */
9236 }
9237 else
9238 {
9239 /* We can't substitute for this parameter pack. We use a flag as
9240 well as the missing_level counter because function parameter
9241 packs don't have a level. */
9245 }
9246 }
9248 /* We cannot expand this expansion expression, because we don't have
9249 all of the argument packs we need. */
9251 {
9253 {
9254 /* We got some full packs, but we can't substitute them in until we
9255 have values for all the packs. So remember these until then. */
9256 tree save_args;
9260 /* The call to add_to_template_args above assumes no overlap
9261 between saved args and new args, so prune away any fake
9262 args, i.e. those that satisfied arg_from_parm_pack_p above. */
9264 {
9270 }
9271 else
9275 }
9276 else
9277 {
9278 /* There were no real arguments, we're just replacing a parameter
9279 pack with another version of itself. Substitute into the
9280 pattern and return a PACK_EXPANSION_*. The caller will need to
9281 deal with that. */
9285 else
9288 }
9290 }
9292 /* We could not find any argument packs that work. */
9297 {
9298 /* We're in a late-specified return type, so create our own local
9299 specializations map; the current map is either NULL or (in the
9300 case of recursive unification) might have bindings that we don't
9301 want to use or alter. */
9304 }
9306 /* For each argument in each argument pack, substitute into the
9307 pattern. */
9310 {
9311 /* For parameter pack, change the substitution of the parameter
9312 pack to the ith argument in its argument pack, then expand
9313 the pattern. */
9315 {
9317 tree arg;
9319 /* Select the Ith argument from the pack. */
9321 {
9323 {
9328 }
9329 else
9331 }
9332 else
9333 {
9338 {
9341 /* Update the corresponding argument. */
9343 }
9344 else
9345 /* Re-use the ARGUMENT_PACK_SELECT. */
9347 }
9349 }
9351 /* Substitute into the PATTERN with the altered arguments. */
9356 else
9360 {
9363 }
9364 }
9366 /* Update ARGS to restore the substitution from parameter packs to
9367 their argument packs. */
9369 {
9374 else
9375 {
9379 /* Update the corresponding argument. */
9383 else
9385 }
9386 }
9389 {
9392 }
9395 }
9397 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
9398 TMPL. We do this using DECL_PARM_INDEX, which should work even with
9399 parameter packs; all parms generated from a function parameter pack will
9400 have the same DECL_PARM_INDEX. */
9402 tree
9404 {
9406 tree patparm;
9409 {
9415 }
9416 else
9417 {
9422 }
9425 }
9427 /* Substitute ARGS into the vector or list of template arguments T. */
9429 static tree
9431 {
9443 {
9445 tree new_arg;
9450 {
9451 /* Substitute into an expansion expression. */
9455 /* Add to the expanded length adjustment the number of
9456 expanded arguments. We subtract one from this
9457 measurement, because the argument pack expression
9458 itself is already counted as 1 in
9459 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
9460 the argument pack is empty. */
9462 }
9464 {
9465 /* Substitute into each of the arguments. */
9471 new_arg,
9485 }
9486 }
9487 else
9496 }
9501 /* Make space for the expanded arguments coming from template
9502 argument packs. */
9504 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
9505 arguments for a member template.
9506 In that case each TREE_VEC in ORIG_T represents a level of template
9507 arguments, and ORIG_T won't carry any non defaulted argument count.
9508 It will rather be the nested TREE_VECs that will carry one.
9509 In other words, ORIG_T carries a non defaulted argument count only
9510 if it doesn't contain any nested TREE_VEC. */
9512 {
9516 }
9518 {
9522 {
9525 /* Now expand the template argument pack "in place". */
9528 }
9529 else
9530 {
9532 out++;
9533 }
9534 }
9537 }
9539 /* Return the result of substituting ARGS into the template parameters
9540 given by PARMS. If there are m levels of ARGS and m + n levels of
9541 PARMS, then the result will contain n levels of PARMS. For
9542 example, if PARMS is `template <class T> template <class U>
9543 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
9544 result will be `template <int*, double, class V>'. */
9546 static tree
9548 {
9552 /* When substituting into a template, we must set
9553 PROCESSING_TEMPLATE_DECL as the template parameters may be
9554 dependent if they are based on one-another, and the dependency
9555 predicates are short-circuit outside of templates. */
9562 {
9563 tree new_vec =
9568 {
9569 tree tuple;
9581 }
9587 }
9592 }
9594 /* Return the result of substituting ARGS into one template parameter
9595 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
9596 parameter and which TREE_PURPOSE is the default argument of the
9597 template parameter. */
9599 static tree
9601 {
9622 }
9624 /* Substitute the ARGS into the indicated aggregate (or enumeration)
9625 type T. If T is not an aggregate or enumeration type, it is
9626 handled as if by tsubst. IN_DECL is as for tsubst. If
9627 ENTERING_SCOPE is nonzero, T is the context for a template which
9628 we are presently tsubst'ing. Return the substituted value. */
9630 static tree
9632 tree args,
9633 tsubst_flags_t complain,
9634 tree in_decl,
9636 {
9641 {
9646 /* Else fall through. */
9650 {
9651 tree argvec;
9652 tree context;
9653 tree r;
9657 /* In "sizeof(X<I>)" we need to evaluate "I". */
9663 /* First, determine the context for the type we are looking
9664 up. */
9667 {
9670 /* If context is a nested class inside a class template,
9671 it may still need to be instantiated (c++/33959). */
9673 }
9675 /* Then, figure out what arguments are appropriate for the
9676 type we are trying to find. For example, given:
9678 template <class T> struct S;
9679 template <class T, class U> void f(T, U) { S<U> su; }
9681 and supposing that we are instantiating f<int, double>,
9682 then our ARGS will be {int, double}, but, when looking up
9683 S we only want {double}. */
9688 else
9689 {
9693 }
9699 }
9700 else
9701 /* This is not a template type, so there's nothing to do. */
9706 }
9707 }
9709 /* Substitute into the default argument ARG (a default argument for
9710 FN), which has the indicated TYPE. */
9712 tree
9714 {
9719 /* This can happen in invalid code. */
9723 /* This default argument came from a template. Instantiate the
9724 default argument here, not in tsubst. In the case of
9725 something like:
9727 template <class T>
9728 struct S {
9729 static T t();
9730 void f(T = t());
9731 };
9733 we must be careful to do name lookup in the scope of S<T>,
9734 rather than in the current class. */
9736 /* The "this" pointer is not valid in a default argument. */
9738 {
9743 }
9746 /* The default argument expression may cause implicitly defined
9747 member functions to be synthesized, which will result in garbage
9748 collection. We must treat this situation as if we were within
9749 the body of function so as to avoid collecting live data on the
9750 stack. */
9758 /* Restore the "this" pointer. */
9760 {
9763 }
9769 /* Make sure the default argument is reasonable. */
9775 }
9777 /* Substitute into all the default arguments for FN. */
9779 static void
9781 {
9782 tree arg;
9783 tree tmpl_args;
9787 /* If this function is not yet instantiated, we certainly don't need
9788 its default arguments. */
9791 /* Don't do this again for clones. */
9796 arg;
9802 }
9804 /* Substitute the ARGS into the T, which is a _DECL. Return the
9805 result of the substitution. Issue error and warning messages under
9806 control of COMPLAIN. */
9808 static tree
9810 {
9811 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
9812 location_t saved_loc;
9817 /* Set the filename and linenumber to improve error-reporting. */
9822 {
9824 {
9825 /* We can get here when processing a member function template,
9826 member class template, or template template parameter. */
9828 tree spec;
9829 tree tmpl_args;
9830 tree full_args;
9833 {
9834 /* Template template parameter is treated here. */
9847 complain);
9850 }
9852 /* We might already have an instance of this template.
9853 The ARGS are for the surrounding class type, so the
9854 full args contain the tsubst'd args for the context,
9855 plus the innermost args from the template decl. */
9859 /* Because this is a template, the arguments will still be
9860 dependent, even after substitution. If
9861 PROCESSING_TEMPLATE_DECL is not set, the dependency
9862 predicates will short-circuit. */
9870 /* If this is a default template template argument,
9871 tsubst might not have changed anything. */
9878 {
9881 }
9883 /* Make a new template decl. It will be similar to the
9884 original, but will record the current template arguments.
9885 We also create a new function declaration, which is just
9886 like the old one, but points to this new template, rather
9887 than the old one. */
9896 {
9897 tree new_type;
9909 }
9910 else
9911 {
9912 tree new_decl;
9924 }
9930 /* The template parameters for this new template are all the
9931 template parameters for the old template, except the
9932 outermost level of parameters. */
9935 complain);
9941 /* Record this non-type partial instantiation. */
9945 }
9949 {
9950 tree ctx;
9953 tree gen_tmpl;
9954 tree type;
9959 /* Nobody should be tsubst'ing into non-template functions. */
9963 {
9964 tree spec;
9967 /* If T is not dependent, just return it. We have to
9968 increment PROCESSING_TEMPLATE_DECL because
9969 value_dependent_expression_p assumes that nothing is
9970 dependent when PROCESSING_TEMPLATE_DECL is zero. */
9977 /* Calculate the most general template of which R is a
9978 specialization, and the complete set of arguments used to
9979 specialize R. */
9982 (DECL_TEMPLATE_RESULT
9988 /* Check to see if we already have this specialization. */
9993 {
9996 }
9998 /* We can see more levels of arguments than parameters if
9999 there was a specialization of a member template, like
10000 this:
10002 template <class T> struct S { template <class U> void f(); }
10003 template <> template <class U> void S<int>::f(U);
10005 Here, we'll be substituting into the specialization,
10006 because that's where we can find the code we actually
10007 want to generate, but we'll have enough arguments for
10008 the most general template.
10010 We also deal with the peculiar case:
10012 template <class T> struct S {
10013 template <class U> friend void f();
10014 };
10015 template <class U> void f() {}
10016 template S<int>;
10017 template void f<double>();
10019 Here, the ARGS for the instantiation of will be {int,
10020 double}. But, we only need as many ARGS as there are
10021 levels of template parameters in CODE_PATTERN. We are
10022 careful not to get fooled into reducing the ARGS in
10023 situations like:
10025 template <class T> struct S { template <class U> void f(U); }
10026 template <class T> template <> void S<T>::f(int) {}
10028 which we can spot because the pattern will be a
10029 specialization in this case. */
10031 parms_depth =
10036 }
10037 else
10038 {
10039 /* This special case arises when we have something like this:
10041 template <class T> struct S {
10042 friend void f<int>(int, double);
10043 };
10045 Here, the DECL_TI_TEMPLATE for the friend declaration
10046 will be an IDENTIFIER_NODE. We are being called from
10047 tsubst_friend_function, and we want only to create a
10048 new decl (R) with appropriate types so that we can call
10049 determine_specialization. */
10051 }
10054 {
10057 else
10061 }
10062 else
10063 {
10066 }
10071 /* If we hit excessive deduction depth, the type is bogus even if
10072 it isn't error_mark_node, so don't build a decl. */
10076 /* We do NOT check for matching decls pushed separately at this
10077 point, as they may not represent instantiations of this
10078 template, and in any case are considered separate under the
10079 discrete model. */
10083 /* Clear out the mangled name and RTL for the instantiation. */
10086 /* Leave DECL_INITIAL set on deleted instantiations. */
10092 /* Type-conversion operator. Reconstruct the name, in
10093 case it's the name of one of the template's parameters. */
10103 /* If this is an instantiation of a function with internal
10104 linkage, we already know what object file linkage will be
10105 assigned to the instantiation. */
10114 /* We'll re-clone as appropriate in instantiate_template. */
10117 /* If we aren't complaining now, return on error before we register
10118 the specialization so that we'll complain eventually. */
10124 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
10125 this in the special friend case mentioned above where
10126 GEN_TMPL is NULL. */
10128 {
10134 /* We're not supposed to instantiate default arguments
10135 until they are called, for a template. But, for a
10136 declaration like:
10138 template <class T> void f ()
10139 { extern void g(int i = T()); }
10141 we should do the substitution when the template is
10142 instantiated. We handle the member function case in
10143 instantiate_class_template since the default arguments
10144 might refer to other members of the class. */
10149 }
10150 else
10153 /* Copy the list of befriending classes. */
10157 {
10161 in_decl);
10162 }
10165 {
10171 /* If this is an instantiation of a member template, clone it.
10172 If it isn't, that'll be handled by
10173 clone_constructors_and_destructors. */
10176 }
10187 /* Possibly limit visibility based on template args. */
10190 {
10194 }
10202 }
10206 {
10214 {
10215 /* If there is a local specialization that isn't a
10216 parameter pack, it means that we're doing a "simple"
10217 substitution from inside tsubst_pack_expansion. Just
10218 return the local specialization (which will be a single
10219 parm). */
10226 /* Expand the TYPE_PACK_EXPANSION that provides the types for
10227 the parameters in this function parameter pack. */
10231 {
10234 /* Zero-length parameter packs are boring. Just substitute
10235 into the chain. */
10239 }
10240 else
10241 {
10242 /* All we did was update the type. Make a note of that. */
10245 }
10246 }
10248 /* Loop through all of the parameter's we'll build. When T is
10249 a function parameter pack, LEN is the number of expanded
10250 types in EXPANDED_TYPES; otherwise, LEN is 1. */
10253 {
10260 /* We're on the Ith parameter of the function parameter
10261 pack. */
10262 {
10263 /* An argument of a function parameter pack is not a parameter
10264 pack. */
10267 /* Get the Ith type. */
10271 /* Rename the parameter to include the index. */
10274 }
10276 /* We're dealing with a normal parameter. */
10284 {
10287 else
10290 }
10300 /* Keep track of the first new parameter we
10301 generate. That's what will be returned to the
10302 caller. */
10306 /* Build a proper chain of parameters when substituting
10307 into a function parameter pack. */
10310 }
10312 /* If cp_unevaluated_operand is set, we're just looking for a
10313 single dummy parameter, so don't keep going. */
10318 /* FIRST_R contains the start of the chain we've built. */
10320 }
10324 {
10325 tree type;
10335 /* For bit-fields, DECL_INITIAL gives the number of bits. For
10336 non-bit-fields DECL_INITIAL is a non-static data member
10337 initializer, which gets deferred instantiation. */
10343 {
10344 /* Set up DECL_TEMPLATE_INFO so that we can get at the
10345 NSDMI in perform_member_init. Still set DECL_INITIAL
10346 so that we know there is one. */
10351 }
10352 /* We don't have to set DECL_CONTEXT here; it is set by
10353 finish_member_declaration. */
10360 }
10364 /* We reach here only for member using decls. We also need to check
10365 uses_template_parms because DECL_DEPENDENT_P is not set for a
10366 using-declaration that designates a member of the current
10367 instantiation (c++/53549). */
10370 {
10381 else
10382 {
10385 }
10386 }
10387 else
10388 {
10391 }
10396 {
10399 tree spec;
10401 tree ctx;
10407 {
10408 /* If this is the canonical decl, we don't have to
10409 mess with instantiations, and often we can't (for
10410 typename, template type parms and such). Note that
10411 TYPE_NAME is not correct for the above test if
10412 we've copied the type for a typedef. */
10418 }
10420 /* Check to see if we already have the specialization we
10421 need. */
10424 {
10425 /* T is a static data member or namespace-scope entity.
10426 We have to substitute into namespace-scope variables
10427 (even though such entities are never templates) because
10428 of cases like:
10430 template <class T> void f() { extern T t; }
10432 where the entity referenced is not known until
10433 instantiation time. */
10437 {
10439 complain,
10441 /* If CTX is unchanged, then T is in fact the
10442 specialization we want. That situation occurs when
10443 referencing a static data member within in its own
10444 class. We can use pointer equality, rather than
10445 same_type_p, because DECL_CONTEXT is always
10446 canonical... */
10449 /* ... unless T is a member template; in which
10450 case our caller can be willing to create a
10451 specialization of that template represented
10452 by T. */
10456 }
10459 {
10467 }
10468 }
10469 else
10470 {
10471 /* A local variable. */
10473 /* Subsequent calls to pushdecl will fill this in. */
10476 }
10477 /* If we already have the specialization we need, there is
10478 nothing more to do. */
10480 {
10483 }
10486 {
10487 /* Just use name lookup to find a member alias for an anonymous
10488 union, but then add it to the hash table. */
10493 }
10495 /* Create a new node for the specialization we need. */
10498 {
10501 else
10508 }
10510 {
10511 /* Even if the original location is out of scope, the
10512 newly substituted one is not. */
10519 {
10520 /* It may seem that this case cannot occur, since:
10522 typedef void f();
10523 void g() { f x; }
10525 declares a function, not a variable. However:
10527 typedef void f();
10528 template <typename T> void g() { T t; }
10529 template void g<f>();
10531 is an attempt to declare a variable with function
10532 type. */
10534 /* R is not yet sufficiently initialized, so we
10535 just use its name. */
10538 }
10540 /* Wait until cp_finish_decl to set this again, to handle
10541 circular dependency (template/instantiate6.C). */
10546 {
10551 {
10554 }
10556 }
10557 }
10563 /* Clear out the mangled name and RTL for the instantiation. */
10567 /* The initializer must not be expanded until it is required;
10568 see [temp.inst]. */
10574 {
10575 /* Possibly limit visibility based on template args. */
10578 {
10582 }
10584 }
10587 {
10588 /* A static data member declaration is always marked
10589 external when it is declared in-class, even if an
10590 initializer is present. We mimic the non-template
10591 processing here. */
10597 }
10599 {
10600 /* We're substituting this var in a decltype outside of its
10601 scope, such as for a lambda return type. Don't add it to
10602 local_specializations, do perform auto deduction. */
10605 {
10606 tree init
10612 }
10613 }
10614 else
10623 /* Preserve a typedef that names a type. */
10625 {
10628 }
10631 }
10636 }
10637 #undef RETURN
10639 out:
10640 /* Restore the file and line information. */
10644 }
10646 /* Substitute into the ARG_TYPES of a function type.
10647 If END is a TREE_CHAIN, leave it and any following types
10648 un-substituted. */
10650 static tree
10652 tree args,
10653 tree end,
10654 tsubst_flags_t complain,
10655 tree in_decl)
10656 {
10657 tree remaining_arg_types;
10661 tree default_arg;
10672 {
10673 /* For a pack expansion, perform substitution on the
10674 entire expression. Later on, we'll handle the arguments
10675 one-by-one. */
10680 /* So that we'll spin through the parameters, one by one. */
10682 else
10683 {
10684 /* We only partially substituted into the parameter
10685 pack. Our type is TYPE_PACK_EXPANSION. */
10688 }
10689 }
10702 {
10704 {
10708 }
10710 }
10712 /* Do array-to-pointer, function-to-pointer conversion, and ignore
10713 top-level qualifiers as required. */
10716 /* We do not substitute into default arguments here. The standard
10717 mandates that they be instantiated only when needed, which is
10718 done in build_over_call. */
10722 {
10723 /* We've instantiated a template before its default arguments
10724 have been parsed. This can happen for a nested template
10725 class, and is not an error unless we require the default
10726 argument in a call of this function. */
10727 remaining_arg_types =
10730 }
10731 else
10732 remaining_arg_types =
10734 }
10737 }
10739 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
10740 *not* handle the exception-specification for FNTYPE, because the
10741 initial substitution of explicitly provided template parameters
10742 during argument deduction forbids substitution into the
10743 exception-specification:
10745 [temp.deduct]
10747 All references in the function type of the function template to the
10748 corresponding template parameters are replaced by the specified tem-
10749 plate argument values. If a substitution in a template parameter or
10750 in the function type of the function template results in an invalid
10751 type, type deduction fails. [Note: The equivalent substitution in
10752 exception specifications is done only when the function is instanti-
10753 ated, at which point a program is ill-formed if the substitution
10754 results in an invalid type.] */
10756 static tree
10758 tree args,
10759 tsubst_flags_t complain,
10760 tree in_decl)
10761 {
10762 tree return_type;
10763 tree arg_types;
10764 tree fntype;
10766 /* The TYPE_CONTEXT is not used for function/method types. */
10769 /* Substitute the return type. */
10773 /* The standard does not presently indicate that creation of a
10774 function type with an invalid return type is a deduction failure.
10775 However, that is clearly analogous to creating an array of "void"
10776 or a reference to a reference. This is core issue #486. */
10779 {
10781 {
10784 else
10786 }
10788 }
10790 /* Substitute the argument types. */
10796 /* Construct a new type node and return it. */
10798 {
10801 }
10802 else
10803 {
10806 {
10807 /* [temp.deduct]
10809 Type deduction may fail for any of the following
10810 reasons:
10812 -- Attempting to create "pointer to member of T" when T
10813 is not a class type. */
10816 r);
10818 }
10822 }
10826 }
10828 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
10829 ARGS into that specification, and return the substituted
10830 specification. If there is no specification, return NULL_TREE. */
10832 static tree
10834 tree args,
10835 tsubst_flags_t complain,
10836 tree in_decl,
10838 {
10839 tree specs;
10840 tree new_specs;
10845 {
10846 /* A noexcept-specifier. */
10851 {
10852 /* Defer instantiation of noexcept-specifiers to avoid
10853 excessive instantiations (c++/49107). */
10856 {
10857 /* We already partially instantiated this member template,
10858 so combine the new args with the old. */
10863 }
10864 else
10865 {
10868 }
10869 }
10870 else
10871 new_specs = tsubst_copy_and_build
10875 }
10877 {
10880 else
10882 {
10883 tree spec;
10888 {
10889 /* Expand the pack expansion type. */
10892 in_decl);
10898 else
10899 {
10900 /* We're substituting into a member template, so
10901 we got a TYPE_PACK_EXPANSION back. Add that
10902 expansion and move on. */
10906 expanded_specs,
10907 complain);
10910 }
10911 }
10914 {
10917 else
10922 complain);
10923 }
10926 }
10927 }
10929 }
10931 /* Take the tree structure T and replace template parameters used
10932 therein with the argument vector ARGS. IN_DECL is an associated
10933 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
10934 Issue error and warning messages under control of COMPLAIN. Note
10935 that we must be relatively non-tolerant of extensions here, in
10936 order to preserve conformance; if we allow substitutions that
10937 should not be allowed, we may allow argument deductions that should
10938 not succeed, and therefore report ambiguous overload situations
10939 where there are none. In theory, we could allow the substitution,
10940 but indicate that it should have failed, and allow our caller to
10941 make sure that the right thing happens, but we don't try to do this
10942 yet.
10944 This function is used for dealing with types, decls and the like;
10945 for expressions, use tsubst_expr or tsubst_copy. */
10947 tree
10949 {
10972 else
10977 /* Reuse typedefs. We need to do this to handle dependent attributes,
10978 such as attribute aligned. */
10981 {
10985 {
10986 /* DECL represents an alias template and we want to
10987 instantiate it. */
10991 }
10995 {
10999 }
11004 else
11005 /* The typedef is from a non-template context. */
11009 {
11011 r = cp_build_qualified_type_real
11015 }
11016 else
11017 /* We don't have an instantiation yet, so drop the typedef. */
11019 }
11032 {
11058 {
11064 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
11065 needed. */
11071 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
11072 with TREE_SIDE_EFFECTS that indicates this is not an integral
11073 constant expression. */
11076 {
11079 }
11082 }
11088 {
11101 {
11105 /* See through ARGUMENT_PACK_SELECT arguments. */
11107 }
11112 {
11114 /* If ARG is an argument pack, we don't actually want to
11115 perform a substitution here, because substitutions
11116 for argument packs are only done
11117 element-by-element. We can get to this point when
11118 substituting the type of a non-type template
11119 parameter pack, when that type actually contains
11120 template parameter packs from an outer template, e.g.,
11122 template<typename... Types> struct A {
11123 template<Types... Values> struct B { };
11124 }; */
11128 {
11134 return cp_build_qualified_type_real
11136 }
11138 {
11139 /* We are processing a type constructed from a
11140 template template parameter. */
11151 /* Consider this code:
11153 template <template <class> class Template>
11154 struct Internal {
11155 template <class Arg> using Bind = Template<Arg>;
11156 };
11158 template <template <class> class Template, class Arg>
11159 using Instantiate = Template<Arg>; //#0
11161 template <template <class> class Template,
11162 class Argument>
11163 using Bind =
11164 Instantiate<Internal<Template>::template Bind,
11165 Argument>; //#1
11167 When #1 is parsed, the
11168 BOUND_TEMPLATE_TEMPLATE_PARM representing the
11169 parameter `Template' in #0 matches the
11170 UNBOUND_CLASS_TEMPLATE representing the argument
11171 `Internal<Template>::template Bind'; We then want
11172 to assemble the type `Bind<Argument>' that can't
11173 be fully created right now, because
11174 `Internal<Template>' not being complete, the Bind
11175 template cannot be looked up in that context. So
11176 we need to "store" `Bind<Argument>' for later
11177 when the context of Bind becomes complete. Let's
11178 store that in a TYPENAME_TYPE. */
11182 argvec),
11183 typename_type,
11184 complain);
11186 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
11187 are resolving nested-types in the signature of a
11188 member function templates. Otherwise ARG is a
11189 TEMPLATE_DECL and is the real template to be
11190 instantiated. */
11198 complain);
11199 return cp_build_qualified_type_real
11201 }
11202 else
11203 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
11205 }
11208 /* This can happen during the attempted tsubst'ing in
11209 unify. This means that we don't yet have any information
11210 about the template parameter in question. */
11213 /* Early in template argument deduction substitution, we don't
11214 want to reduce the level of 'auto', or it will be confused
11215 with a normal template parm in subsequent deduction. */
11219 /* If we get here, we must have been looking at a parm for a
11220 more deeply nested template. Make a new version of this
11221 template parameter, but with a lower level. */
11223 {
11228 {
11230 r = cp_build_qualified_type_real
11234 }
11235 else
11236 {
11247 /* We have reduced the level of the template
11248 template parameter, but not the levels of its
11249 template parameters, so canonical_type_parameter
11250 will not be able to find the canonical template
11251 template parameter for this level. Thus, we
11252 require structural equality checking to compare
11253 TEMPLATE_TEMPLATE_PARMs. */
11257 else
11261 {
11269 }
11270 }
11279 }
11282 }
11285 {
11293 {
11297 }
11300 {
11304 }
11307 {
11311 }
11317 }
11320 /* We should never be tsubsting a binfo. */
11324 /* A vector of template arguments. */
11330 {
11334 /* [temp.deduct]
11336 Type deduction may fail for any of the following
11337 reasons:
11339 -- Attempting to create a pointer to reference type.
11340 -- Attempting to create a reference to a reference type or
11341 a reference to void.
11343 Core issue 106 says that creating a reference to a reference
11344 during instantiation is no longer a cause for failure. We
11345 only enforce this check in strict C++98 mode. */
11349 {
11352 /* We keep track of the last time we issued this error
11353 message to avoid spewing a ton of messages during a
11354 single bad template instantiation. */
11357 {
11362 else
11365 }
11368 }
11370 {
11374 }
11376 /* In C++0x, during template argument substitution, when there is an
11377 attempt to create a reference to a reference type, reference
11378 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
11380 "If a template-argument for a template-parameter T names a type
11381 that is a reference to a type A, an attempt to create the type
11382 'lvalue reference to cv T' creates the type 'lvalue reference to
11383 A,' while an attempt to create the type type rvalue reference to
11384 cv T' creates the type T"
11385 */
11386 r = cp_build_reference_type
11389 else
11394 /* Will this ever be needed for TYPE_..._TO values? */
11398 }
11400 {
11403 {
11404 /* [temp.deduct]
11406 Type deduction may fail for any of the following
11407 reasons:
11409 -- Attempting to create "pointer to member of T" when T
11410 is not a class type. */
11414 }
11416 {
11420 }
11422 {
11426 }
11429 {
11430 /* The type of the implicit object parameter gets its
11431 cv-qualifiers from the FUNCTION_TYPE. */
11432 tree memptr;
11436 complain);
11437 }
11438 else
11441 complain);
11442 }
11445 {
11446 tree fntype;
11447 tree specs;
11452 /* Substitute the exception specification. */
11460 }
11462 {
11467 /* As an optimization, we avoid regenerating the array type if
11468 it will obviously be the same as T. */
11472 /* These checks should match the ones in grokdeclarator.
11474 [temp.deduct]
11476 The deduction may fail for any of the following reasons:
11478 -- Attempting to create an array with an element type that
11479 is void, a function type, or a reference type, or [DR337]
11480 an abstract class type. */
11484 {
11488 }
11490 {
11493 type);
11495 }
11500 {
11503 }
11506 }
11509 {
11519 {
11523 }
11525 {
11526 /* Normally, make_typename_type does not require that the CTX
11527 have complete type in order to allow things like:
11529 template <class T> struct S { typename S<T>::X Y; };
11531 But, such constructs have already been resolved by this
11532 point, so here CTX really should have complete type, unless
11533 it's a partial instantiation. */
11536 {
11540 }
11541 }
11548 {
11551 }
11554 {
11556 {
11560 else
11562 }
11564 {
11568 else
11570 }
11571 }
11573 return cp_build_qualified_type_real
11575 }
11578 {
11590 }
11593 {
11594 tree type;
11610 complain);
11611 }
11614 {
11615 tree type;
11631 else
11632 type = finish_decltype_type
11637 complain);
11638 }
11641 {
11645 }
11649 {
11651 tree packed_out =
11653 args,
11654 complain,
11655 in_decl);
11658 /* For template nontype argument packs, also substitute into
11659 the type. */
11664 }
11679 /* We should use one of the expression tsubsts for these codes. */
11685 }
11686 }
11688 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
11689 type of the expression on the left-hand side of the "." or "->"
11690 operator. */
11692 static tree
11695 {
11696 tree name;
11697 tree qualifying_scope;
11698 tree fns;
11699 tree optype;
11704 /* A baselink indicates a function from a base class. Both the
11705 BASELINK_ACCESS_BINFO and the base class referenced may
11706 indicate bases of the template class, rather than the
11707 instantiated class. In addition, lookups that were not
11708 ambiguous before may be ambiguous now. Therefore, we perform
11709 the lookup again. */
11716 {
11723 }
11731 /* If lookup found a single function, mark it as used at this
11732 point. (If it lookup found multiple functions the one selected
11733 later by overload resolution will be marked as used at that
11734 point.) */
11740 /* Add back the template arguments, if present. */
11745 template_args);
11746 /* Update the conversion operator type. */
11754 qualifying_scope,
11755 object_type);
11757 }
11759 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
11760 true if the qualified-id will be a postfix-expression in-and-of
11761 itself; false if more of the postfix-expression follows the
11762 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
11763 of "&". */
11765 static tree
11769 {
11770 tree expr;
11771 tree scope;
11772 tree name;
11774 tree template_args;
11779 /* Figure out what name to look up. */
11782 {
11790 }
11791 else
11792 {
11795 }
11797 /* Substitute into the qualifying scope. When there are no ARGS, we
11798 are just trying to simplify a non-dependent expression. In that
11799 case the qualifying scope may be dependent, and, in any case,
11800 substituting will not help. */
11803 {
11806 }
11807 else
11811 {
11816 }
11819 {
11821 {
11822 /* A BIT_NOT_EXPR is used to represent a destructor. */
11824 {
11828 }
11829 else
11832 }
11833 else
11837 {
11839 {
11843 }
11845 }
11846 }
11849 {
11851 scope);
11852 /* Remember that there was a reference to this entity. */
11854 }
11857 {
11863 }
11872 {
11873 expr = (adjust_result_of_qualified_name_lookup
11875 expr = (finish_qualified_id_expr
11879 }
11881 /* Expressions do not generally have reference type. */
11883 /* However, if we're about to form a pointer-to-member, we just
11884 want the referenced member referenced. */
11889 }
11891 /* Like tsubst, but deals with expressions. This function just replaces
11892 template parms; to finish processing the resultant expression, use
11893 tsubst_copy_and_build or tsubst_expr. */
11895 static tree
11897 {
11899 tree r;
11907 {
11912 {
11913 /* We get here for a use of 'this' in an NSDMI. */
11919 /* This can happen for a parameter name used later in a function
11920 declaration (such as in a late-specified return type). Just
11921 make a dummy decl, since it's only used for its type. */
11924 /* Give it the template pattern as its context; its true context
11925 hasn't been instantiated yet and this is good enough for
11926 mangling. */
11928 }
11936 {
11937 tree enum_type;
11938 tree v;
11942 /* There is no need to substitute into namespace-scope
11943 enumerators. */
11946 /* If ARGS is NULL, then T is known to be non-dependent. */
11950 /* Unfortunately, we cannot just call lookup_name here.
11951 Consider:
11953 template <int I> int f() {
11954 enum E { a = I };
11955 struct S { void g() { E e = a; } };
11956 };
11958 When we instantiate f<7>::S::g(), say, lookup_name is not
11959 clever enough to find f<7>::a. */
11960 enum_type
11970 /* We didn't find the name. That should never happen; if
11971 name-lookup found it during preliminary parsing, we
11972 should find it again here during instantiation. */
11974 }
11979 {
11980 tree ctx;
11985 {
11988 {
11992 }
11994 }
11995 }
12011 /* An OVERLOAD will always be a non-dependent overload set; an
12012 overload set from function scope will just be represented with an
12013 IDENTIFIER_NODE, and from class scope with a BASELINK. */
12028 {
12029 /* Template template argument like the following example need
12030 special treatment:
12032 template <template <class> class TT> struct C {};
12033 template <class T> struct D {
12034 template <class U> struct E {};
12035 C<E> c; // #1
12036 };
12037 D<int> d; // #2
12039 We are processing the template argument `E' in #1 for
12040 the template instantiation #2. Originally, `E' is a
12041 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
12042 have to substitute this with one having context `D<int>'. */
12046 }
12047 else
12048 /* Ordinary template template argument. */
12059 return build1
12065 {
12075 /* We only want to compute the number of arguments. */
12089 {
12096 else
12099 }
12100 else
12102 }
12104 {
12112 }
12113 /* Fall through */
12128 return build1
12133 {
12134 tree object;
12135 tree name;
12140 {
12144 }
12147 {
12157 }
12162 in_decl);
12163 else
12166 }
12204 return build_nt
12217 return build_nt
12224 {
12232 }
12237 {
12238 r = build_nt
12244 }
12247 {
12248 r = build_nt
12254 }
12257 {
12258 r = build_nt
12264 }
12267 {
12268 /* Substituted template arguments */
12277 }
12280 {
12300 }
12325 {
12328 }
12329 else
12333 /* This is handled by tsubst_copy_and_build. */
12339 in_decl),
12343 /* We shouldn't have built any of these during initial template
12344 generation. Instead, they should be built during instantiation
12345 in response to the saved STMT_IS_FULL_EXPR_P setting. */
12349 r = build2
12369 {
12370 /* Instantiate any typedefs in the type. */
12375 }
12378 /* These can sometimes show up in a partial instantiation, but never
12379 involve template parms. */
12384 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
12387 }
12388 }
12390 /* Like tsubst_copy, but specifically for OpenMP clauses. */
12392 static tree
12394 tree in_decl)
12395 {
12399 {
12405 {
12408 {
12414 }
12415 /* FALLTHRU */
12439 }
12440 }
12443 }
12445 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
12447 static tree
12449 tree in_decl)
12450 {
12451 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
12471 {
12474 else
12475 {
12479 }
12480 }
12485 #undef RECUR
12486 }
12488 /* Substitute one OMP_FOR iterator. */
12490 static void
12495 {
12496 #define RECUR(NODE) \
12497 tsubst_expr ((NODE), args, complain, in_decl, \
12498 integral_constant_expression_p)
12506 /* Do this before substituting into decl to handle 'auto'. */
12511 {
12515 }
12520 {
12527 complain);
12528 else
12535 }
12538 {
12539 tree c;
12541 {
12552 }
12554 {
12559 {
12562 }
12563 }
12564 }
12570 else
12574 {
12585 {
12592 }
12593 else
12599 {
12605 }
12609 {
12616 }
12617 else
12623 }
12629 #undef RECUR
12630 }
12632 /* Like tsubst_copy for expressions, etc. but also does semantic
12633 processing. */
12635 static tree
12638 {
12639 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12640 #define RECUR(NODE) \
12641 tsubst_expr ((NODE), args, complain, in_decl, \
12642 integral_constant_expression_p)
12645 tree r;
12646 location_t loc;
12658 {
12660 {
12661 tree_stmt_iterator i;
12665 }
12680 else
12689 {
12691 tree init;
12697 {
12700 tree decl;
12708 else
12710 }
12711 else
12712 {
12716 {
12717 /* By marking the declaration as instantiated, we avoid
12718 trying to instantiate it. Since instantiate_decl can't
12719 handle local variables, and since we've already done
12720 all that needs to be done, that's the right thing to
12721 do. */
12726 /* Anonymous aggregates are a special case. */
12729 {
12732 }
12735 else
12736 {
12741 {
12742 /* For __PRETTY_FUNCTION__ we have to adjust the
12743 initializer. */
12747 }
12748 else
12749 {
12753 {
12754 /* If we had an initializer but it
12755 instantiated to nothing,
12756 value-initialize the object. This will
12757 only occur when the initializer was a
12758 pack expansion where the parameter packs
12759 used in that expansion were of length
12760 zero. */
12762 complain);
12765 }
12766 else
12768 }
12771 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
12774 }
12775 }
12776 }
12779 }
12794 {
12804 }
12831 {
12835 }
12843 else
12851 else
12878 {
12880 tree label;
12885 }
12891 /* Computed goto's must be tsubst'd into. On the other hand,
12892 non-computed gotos must not be; the identifier in question
12893 will have no binding. */
12895 else
12901 tmp = finish_asm_stmt
12908 {
12913 }
12918 {
12923 }
12924 else
12925 {
12930 else
12937 else
12943 else
12945 }
12949 {
12953 {
12955 /* Prevent instantiate_decl from trying to instantiate
12956 this variable. We've already done all that needs to be
12957 done. */
12960 }
12965 }
12971 {
12972 /* Local classes are not independent templates; they are
12973 instantiated along with their containing function. And this
12974 way we don't have to deal with pushing out of one local class
12975 to instantiate a member of another local class. */
12976 tree fn;
12977 /* Closures are handled by the LAMBDA_EXPR. */
12983 }
12987 {
12988 tree condition;
12991 condition =
12993 args,
13002 }
13023 {
13040 integral_constant_expression_p);
13054 }
13086 {
13091 {
13094 }
13099 }
13100 else
13101 {
13108 {
13111 }
13114 {
13119 {
13122 }
13126 }
13127 else
13128 {
13132 }
13134 }
13138 {
13144 {
13148 {
13153 }
13157 }
13158 else
13159 {
13164 }
13165 }
13183 /* If the first operand was a statement, we're done with it. */
13187 complain));
13194 integral_constant_expression_p));
13195 }
13198 out:
13201 #undef RECUR
13202 #undef RETURN
13203 }
13205 /* T is a postfix-expression that is not being used in a function
13206 call. Return the substituted version of T. */
13208 static tree
13210 tsubst_flags_t complain,
13211 tree in_decl)
13212 {
13216 else
13222 }
13224 /* Like tsubst but deals with expressions and performs semantic
13225 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
13227 tree
13229 tree args,
13230 tsubst_flags_t complain,
13231 tree in_decl,
13234 {
13235 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
13236 #define RECUR(NODE) \
13237 tsubst_copy_and_build (NODE, args, complain, in_decl, \
13239 integral_constant_expression_p)
13242 location_t loc;
13252 {
13255 /* Fall through. */
13257 {
13258 tree decl;
13259 cp_id_kind idk;
13264 {
13267 }
13269 /* Look up the name. */
13272 /* By convention, expressions use ERROR_MARK_NODE to indicate
13273 failure, not NULL_TREE. */
13279 integral_constant_expression_p,
13287 input_location);
13291 {
13295 }
13297 }
13300 {
13301 tree object;
13309 {
13312 }
13313 else
13320 else
13322 }
13325 {
13329 {
13330 /* A type conversion to reference type will be enclosed in
13331 such an indirect ref, but the substitution of the cast
13332 will have also added such an indirect ref. */
13335 }
13336 else
13339 }
13347 {
13354 flags));
13355 }
13368 {
13369 tree type;
13375 {
13380 }
13386 {
13404 }
13408 }
13440 else
13442 in_decl);
13476 {
13477 tree r;
13481 r = build_x_binary_op
13485 ? ERROR_MARK
13489 ? ERROR_MARK
13492 complain);
13499 }
13513 /* Fall through */
13516 {
13517 tree r;
13523 {
13524 /* When there are no ARGS, we are trying to evaluate a
13525 non-dependent expression from the parser. Trying to do
13526 the substitutions may not work. */
13529 }
13530 else
13531 {
13536 else
13539 /*integral_constant_expression_p=*/
13543 }
13547 else
13551 {
13553 {
13555 {
13559 }
13560 else
13564 }
13566 }
13568 }
13571 {
13581 }
13595 {
13596 tree r = build_x_modify_expr
13601 complain);
13602 /* TREE_NO_WARNING must be set if either the expression was
13603 parenthesized or it uses an operator such as >>= rather
13604 than plain assignment. In the former case, it was already
13605 set and must be copied. In the latter case,
13606 build_x_modify_expr sets it and it must not be reset
13607 here. */
13611 }
13616 /* Remember that there was a reference to this entity. */
13622 {
13627 tree ret;
13631 else
13632 {
13636 }
13638 /* If there was an initializer in the original tree, but it
13639 instantiated to an empty list, then we should pass a
13640 non-NULL empty vector to tell build_new that it was an
13641 empty initializer() rather than no initializer. This can
13642 only happen when the initializer is a pack expansion whose
13643 parameter packs are of length zero. */
13646 else
13647 {
13651 else
13652 {
13655 }
13656 }
13663 complain);
13671 }
13679 complain));
13685 complain));
13688 {
13689 tree function;
13694 tree ret;
13697 /* When we parsed the expression, we determined whether or
13698 not Koenig lookup should be performed. */
13701 {
13706 }
13708 {
13709 /* Do nothing; calling tsubst_copy_and_build on an identifier
13710 would incorrectly perform unqualified lookup again.
13712 Note that we can also have an IDENTIFIER_NODE if the earlier
13713 unqualified lookup found a member function; in that case
13714 koenig_p will be false and we do want to do the lookup
13715 again to find the instantiated member function.
13717 FIXME but doing that causes c++/15272, so we need to stop
13718 using IDENTIFIER_NODE in that situation. */
13720 }
13721 else
13722 {
13724 {
13730 }
13731 else
13735 in_decl,
13737 integral_constant_expression_p);
13741 }
13746 {
13751 else
13752 {
13753 /* Expand the pack expansion and push each entry onto
13754 CALL_ARGS. */
13757 {
13762 {
13767 }
13768 }
13769 else
13770 {
13771 /* A partial substitution. Add one entry. */
13773 }
13774 }
13775 }
13777 /* We do not perform argument-dependent lookup if normal
13778 lookup finds a non-function, in accordance with the
13779 expected resolution of DR 218. */
13782 /* If lookup found a member function, the Koenig lookup is
13783 not appropriate, even if an unqualified-name was used
13784 to denote the function. */
13787 /* Only do this when substitution turns a dependent call
13788 into a non-dependent call. */
13792 tf_none);
13796 {
13798 {
13799 /* For backwards compatibility and good diagnostics, try
13800 the unqualified lookup again if we aren't in SFINAE
13801 context. */
13802 tree unq = (tsubst_copy_and_build
13804 integral_constant_expression_p));
13809 {
13818 "%qD was not declared in this scope, "
13819 "and no declarations were found by "
13820 "argument-dependent lookup at the point "
13825 {
13827 "declarations in dependent base %qT are "
13833 else
13837 }
13838 else
13842 }
13843 }
13845 {
13850 }
13851 }
13853 /* Remember that there was a reference to this entity. */
13859 complain);
13861 {
13876 complain);
13877 else
13878 ret = (build_new_method_call
13883 complain));
13884 }
13885 else
13888 koenig_p,
13889 complain);
13894 }
13897 {
13902 {
13904 {
13909 }
13910 else
13911 {
13916 }
13917 }
13918 else
13919 {
13922 }
13926 }
13935 {
13943 {
13944 /* We have pack expansions, so expand those and
13945 create a new list out of it. */
13948 tree chain;
13951 /* Expand the argument expressions. */
13959 /* Build the rest of the list. */
13964 /* Determine the number of arguments. */
13966 {
13969 }
13972 else
13973 {
13974 /* Since we only performed a partial substitution into
13975 the argument pack, we only RETURN (a single list
13976 node. */
13983 }
13985 /* Convert the argument vectors into a TREE_LIST */
13988 {
13989 /* Grab the Ith values. */
13990 i--;
13993 value
13997 /* Build the list (backwards). */
13999 }
14002 }
14018 }
14021 {
14022 tree object;
14023 tree object_type;
14024 tree member;
14028 /* Remember that there was a reference to this entity. */
14038 else
14046 {
14048 {
14053 {
14056 }
14058 {
14062 }
14063 }
14064 }
14067 {
14068 /* Lookup the template functions now that we know what the
14069 scope is. */
14077 {
14080 args);
14081 member = (adjust_result_of_qualified_name_lookup
14083 object_type));
14084 }
14085 else
14086 {
14088 input_location);
14090 }
14091 }
14095 {
14097 {
14101 else
14104 }
14106 }
14112 complain));
14113 }
14120 {
14128 tree r;
14133 /* digest_init will do the wrong thing if we let it. */
14137 /* We do not want to process the index of aggregate
14138 initializers as they are identifier nodes which will be
14139 looked up by digest_init. */
14145 {
14150 {
14151 /* Substitute into the pack expansion. */
14153 in_decl);
14157 ;
14159 /* Just move the argument into place. */
14161 else
14162 {
14163 /* Update the length of the final CONSTRUCTOR
14164 arguments vector, and note that we will need to
14165 copy.*/
14168 }
14169 }
14170 else
14172 }
14175 {
14180 {
14182 {
14187 }
14188 else
14190 }
14191 }
14201 }
14204 {
14207 {
14210 }
14211 else
14212 {
14215 }
14216 }
14221 /* Fall through */
14224 {
14228 /* If the original type was a reference, we'll be wrapped in
14229 the appropriate INDIRECT_REF. */
14232 }
14243 {
14252 }
14255 {
14261 integral_constant_expression_p);
14265 /* If the resulting list of expression statement is empty,
14266 fold it further into void_zero_node. */
14271 }
14274 {
14288 /* For a function scope, we want to use tsubst so that we don't
14289 complain about referring to an auto function before its return
14290 type has been deduced. Otherwise, we want to use tsubst_copy so
14291 that we look up the existing field/parameter/variable rather
14292 than build a new one. */
14297 else
14306 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
14308 /* Now that we know visibility, instantiate the type so we have a
14309 declaration of the op() for later calls to lambda_function. */
14312 /* The capture list refers to closure members, so this needs to
14313 wait until after we finish instantiating the type. */
14318 }
14321 /* We can get here for a constant initializer of non-dependent type.
14322 FIXME stop folding in cp_parser_initializer_clause. */
14324 {
14326 complain);
14329 }
14333 integral_constant_expression_p));
14336 /* Handle Objective-C++ constructs, if appropriate. */
14337 {
14338 tree subst
14343 }
14345 }
14347 #undef RECUR
14348 #undef RETURN
14349 out:
14352 }
14354 /* Verify that the instantiated ARGS are valid. For type arguments,
14355 make sure that the type's linkage is ok. For non-type arguments,
14356 make sure they are constants if they are integral or enumerations.
14357 Emit an error under control of COMPLAIN, and return TRUE on error. */
14359 static bool
14361 {
14365 {
14375 }
14377 {
14378 /* [basic.link]: A name with no linkage (notably, the name
14379 of a class or enumeration declared in a local scope)
14380 shall not be used to declare an entity with linkage.
14381 This implies that names with no linkage cannot be used as
14382 template arguments
14384 DR 757 relaxes this restriction for C++0x. */
14389 {
14390 /* DR 488 makes use of a type with no linkage cause
14391 type deduction to fail. */
14393 {
14396 else
14399 }
14401 }
14402 /* In order to avoid all sorts of complications, we do not
14403 allow variably-modified types as template arguments. */
14405 {
14409 }
14410 }
14411 /* A non-type argument of integral or enumerated type must be a
14412 constant. */
14416 {
14420 }
14422 }
14424 static bool
14426 {
14431 {
14434 }
14438 }
14440 /* We're out of SFINAE context now, so generate diagnostics for the access
14441 errors we saw earlier when instantiating D from TMPL and ARGS. */
14443 static void
14445 {
14457 }
14459 /* Instantiate the indicated variable, function, or alias template TMPL with
14460 the template arguments in TARG_PTR. */
14462 static tree
14464 {
14466 tree fndecl;
14467 tree gen_tmpl;
14468 tree spec;
14476 /* If this function is a clone, handle it specially. */
14478 {
14479 tree spec;
14480 tree clone;
14482 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
14483 DECL_CLONED_FUNCTION. */
14489 /* Look for the clone. */
14493 /* We should always have found the clone by now. */
14496 }
14498 /* Check to see if we already have this specialization. */
14501 /* The TMPL is a partial instantiation. To get a full set of
14502 arguments we must add the arguments used to perform the
14503 partial instantiation. */
14505 targ_ptr);
14507 /* It would be nice to avoid hashing here and then again in tsubst_decl,
14508 but it doesn't seem to be on the hot path. */
14517 {
14519 {
14523 }
14525 }
14528 complain))
14531 /* We are building a FUNCTION_DECL, during which the access of its
14532 parameters and return types have to be checked. However this
14533 FUNCTION_DECL which is the desired context for access checking
14534 is not built yet. We solve this chicken-and-egg problem by
14535 deferring all checks until we have the FUNCTION_DECL. */
14538 /* Instantiation of the function happens in the context of the function
14539 template, not the context of the overload resolution we're doing. */
14541 /* If there are dependent arguments, e.g. because we're doing partial
14542 ordering, make sure processing_template_decl stays set. */
14546 {
14550 }
14551 /* Substitute template parameters to obtain the specialization. */
14559 {
14562 }
14564 /* The DECL_TI_TEMPLATE should always be the immediate parent
14565 template, not the most general template. */
14568 /* Now we know the specialization, compute access previously
14569 deferred. */
14576 /* If we've just instantiated the main entry point for a function,
14577 instantiate all the alternate entry points as well. We do this
14578 by cloning the instantiation of the main entry point, not by
14579 instantiating the template clones. */
14584 {
14586 {
14587 /* Remember to reinstantiate when we're out of SFINAE so the user
14588 can see the errors. */
14590 }
14592 }
14594 }
14596 /* Wrapper for instantiate_template_1. */
14598 tree
14600 {
14601 tree ret;
14606 }
14608 /* Instantiate the alias template TMPL with ARGS. Also push a template
14609 instantiation level, which instantiate_template doesn't do because
14610 functions and variables have sufficient context established by the
14611 callers. */
14613 static tree
14615 {
14622 {
14625 }
14628 /* We can't free this if a pending_template entry or last_error_tinst_level
14629 is pointing at it. */
14635 }
14637 /* PARM is a template parameter pack for FN. Returns true iff
14638 PARM is used in a deducible way in the argument list of FN. */
14640 static bool
14642 {
14645 {
14647 tree packs;
14653 {
14654 /* The template parameter pack is used in a function parameter
14655 pack. If this is the end of the parameter list, the
14656 template parameter pack is deducible. */
14659 else
14660 /* Otherwise, not. Well, it could be deduced from
14661 a non-pack parameter, but doing so would end up with
14662 a deduction mismatch, so don't bother. */
14664 }
14665 }
14666 /* The template parameter pack isn't used in any function parameter
14667 packs, but it might be used deeper, e.g. tuple<Args...>. */
14669 }
14671 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
14672 NARGS elements of the arguments that are being used when calling
14673 it. TARGS is a vector into which the deduced template arguments
14674 are placed.
14676 Return zero for success, 2 for an incomplete match that doesn't resolve
14677 all the types, and 1 for complete failure. An error message will be
14678 printed only for an incomplete match.
14680 If FN is a conversion operator, or we are trying to produce a specific
14681 specialization, RETURN_TYPE is the return type desired.
14683 The EXPLICIT_TARGS are explicit template arguments provided via a
14684 template-id.
14686 The parameter STRICT is one of:
14688 DEDUCE_CALL:
14689 We are deducing arguments for a function call, as in
14690 [temp.deduct.call].
14692 DEDUCE_CONV:
14693 We are deducing arguments for a conversion function, as in
14694 [temp.deduct.conv].
14696 DEDUCE_EXACT:
14697 We are deducing arguments when doing an explicit instantiation
14698 as in [temp.explicit], when determining an explicit specialization
14699 as in [temp.expl.spec], or when taking the address of a function
14700 template, as in [temp.deduct.funcaddr]. */
14702 tree
14704 tree explicit_targs,
14705 tree targs,
14708 tree return_type,
14709 unification_kind_t strict,
14712 {
14713 tree parms;
14714 tree fntype;
14722 tree tinst;
14725 /* Adjust any explicit template arguments before entering the
14726 substitution context. */
14728 {
14729 explicit_targs
14731 complain,
14736 }
14738 /* In C++0x, it's possible to have a function template whose type depends
14739 on itself recursively. This is most obvious with decltype, but can also
14740 occur with enumeration scope (c++/48969). So we need to catch infinite
14741 recursion and reject the substitution at deduction time; this function
14742 will return error_mark_node for any repeated substitution.
14744 This also catches excessive recursion such as when f<N> depends on
14745 f<N-1> across all integers, and returns error_mark_node for all the
14746 substitutions back up to the initial one.
14748 This is, of course, not reentrant. */
14753 {
14757 }
14765 {
14766 /* [temp.deduct]
14768 The specified template arguments must match the template
14769 parameters in kind (i.e., type, nontype, template), and there
14770 must not be more arguments than there are parameters;
14771 otherwise type deduction fails.
14773 Nontype arguments must match the types of the corresponding
14774 nontype template parameters, or must be convertible to the
14775 types of the corresponding nontype parameters as specified in
14776 _temp.arg.nontype_, otherwise type deduction fails.
14778 All references in the function type of the function template
14779 to the corresponding template parameters are replaced by the
14780 specified template argument values. If a substitution in a
14781 template parameter or in the function type of the function
14782 template results in an invalid type, type deduction fails. */
14787 /* Substitute the explicit args into the function type. This is
14788 necessary so that, for instance, explicitly declared function
14789 arguments can match null pointed constants. If we were given
14790 an incomplete set of explicit args, we must not do semantic
14791 processing during substitution as we could create partial
14792 instantiations. */
14794 {
14799 /* Dig out the actual parm. */
14802 {
14805 }
14807 {
14810 }
14813 /* No explicit argument for this template parameter. */
14817 {
14818 /* Mark the argument pack as "incomplete". We could
14819 still deduce more arguments during unification.
14820 We remove this mark in type_unification_real. */
14822 {
14826 }
14828 /* We have some incomplete argument packs. */
14830 }
14831 }
14843 /* Place the explicitly specified arguments in TARGS. */
14846 }
14848 /* Never do unification on the 'this' parameter. */
14852 {
14861 }
14863 /* We allow incomplete unification without an error message here
14864 because the standard doesn't seem to explicitly prohibit it. Our
14865 callers must be ready to deal with unification failures in any
14866 event. */
14876 /* Now that we have bindings for all of the template arguments,
14877 ensure that the arguments deduced for the template template
14878 parameters have compatible template parameter lists. We cannot
14879 check this property before we have deduced all template
14880 arguments, because the template parameter types of a template
14881 template parameter might depend on prior template parameters
14882 deduced after the template template parameter. The following
14883 ill-formed example illustrates this issue:
14885 template<typename T, template<T> class C> void f(C<5>, T);
14887 template<int N> struct X {};
14889 void g() {
14890 f(X<5>(), 5l); // error: template argument deduction fails
14891 }
14893 The template parameter list of 'C' depends on the template type
14894 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
14895 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
14896 time that we deduce 'C'. */
14899 {
14902 }
14904 /* All is well so far. Now, check:
14906 [temp.deduct]
14908 When all template arguments have been deduced, all uses of
14909 template parameters in nondeduced contexts are replaced with
14910 the corresponding deduced argument values. If the
14911 substitution results in an invalid type, as described above,
14912 type deduction fails. */
14917 /* Now perform any access checks encountered during deduction, such as
14918 for default template arguments. */
14925 /* If we're looking for an exact match, check that what we got
14926 is indeed an exact match. It might not be if some template
14927 parameters are used in non-deduced contexts. */
14929 {
14933 tree sarg
14939 {
14943 }
14944 }
14948 fail:
14952 {
14954 /* Reset once we're all the way out. */
14956 }
14959 /* We can't free this if a pending_template entry or last_error_tinst_level
14960 is pointing at it. */
14966 }
14968 /* Adjust types before performing type deduction, as described in
14969 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
14970 sections are symmetric. PARM is the type of a function parameter
14971 or the return type of the conversion function. ARG is the type of
14972 the argument passed to the call, or the type of the value
14973 initialized with the result of the conversion function.
14974 ARG_EXPR is the original argument expression, which may be null. */
14976 static int
14980 tree arg_expr)
14981 {
14985 {
14990 {
14991 /* Swap PARM and ARG throughout the remainder of this
14992 function; the handling is precisely symmetric since PARM
14993 will initialize ARG rather than vice versa. */
14998 }
15001 /* Core issue #873: Do the DR606 thing (see below) for these cases,
15002 too, but here handle it by stripping the reference from PARM
15003 rather than by adding it to ARG. */
15011 /* Nothing else to do in this case. */
15016 }
15019 {
15020 /* [temp.deduct.call]
15022 If P is not a reference type:
15024 --If A is an array type, the pointer type produced by the
15025 array-to-pointer standard conversion (_conv.array_) is
15026 used in place of A for type deduction; otherwise,
15028 --If A is a function type, the pointer type produced by
15029 the function-to-pointer standard conversion
15030 (_conv.func_) is used in place of A for type deduction;
15031 otherwise,
15033 --If A is a cv-qualified type, the top level
15034 cv-qualifiers of A's type are ignored for type
15035 deduction. */
15040 else
15042 }
15044 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
15045 of the form T&&, where T is a template parameter, and the argument
15046 is an lvalue, T is deduced as A& */
15052 /* try_one_overload doesn't provide an arg_expr, but
15053 functions are always lvalues. */
15057 /* [temp.deduct.call]
15059 If P is a cv-qualified type, the top level cv-qualifiers
15060 of P's type are ignored for type deduction. If P is a
15061 reference type, the type referred to by P is used for
15062 type deduction. */
15065 {
15068 }
15070 /* DR 322. For conversion deduction, remove a reference type on parm
15071 too (which has been swapped into ARG). */
15076 }
15078 /* Subroutine of unify_one_argument. PARM is a function parameter of a
15079 template which does contain any deducible template parameters; check if
15080 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
15081 unify_one_argument. */
15083 static int
15086 {
15087 tree type;
15091 else
15098 {
15102 }
15104 {
15109 }
15113 else
15115 }
15117 /* Subroutine of type_unification_real and unify_pack_expansion to
15118 handle unification of a single P/A pair. Parameters are as
15119 for those functions. */
15121 static int
15125 {
15132 /* We can't deduce anything from this, but we might get all the
15133 template args from other function args. */
15136 /* FIXME uses_deducible_template_parms */
15139 explain_p);
15142 {
15144 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
15145 | UNIFY_ALLOW_MORE_CV_QUAL
15159 }
15161 /* We only do these transformations if this is the top-level
15162 parameter_type_list in a call or declaration matching; in other
15163 situations (nested function declarators, template argument lists) we
15164 won't be comparing a type to an expression, and we don't do any type
15165 adjustments. */
15167 {
15169 {
15172 {
15173 /* [temp.deduct.type] A template-argument can be
15174 deduced from a pointer to function or pointer
15175 to member function argument if the set of
15176 overloaded functions does not contain function
15177 templates and at most one of a set of
15178 overloaded functions provides a unique
15179 match. */
15186 }
15192 }
15194 arg_strict |=
15196 }
15197 else
15201 /* For deduction from an init-list we need the actual list. */
15205 }
15207 /* Most parms like fn_type_unification.
15209 If SUBR is 1, we're being called recursively (to unify the
15210 arguments of a function or method parameter of a function
15211 template). */
15213 static int
15215 tree targs,
15216 tree xparms,
15220 unification_kind_t strict,
15223 {
15228 tree parms;
15237 /* Reset the number of non-defaulted template arguments contained
15238 in TARGS. */
15241 again:
15249 {
15254 /* For a function parameter pack that occurs at the end of the
15255 parameter-declaration-list, the type A of each remaining
15256 argument of the call is compared with the type P of the
15257 declarator-id of the function parameter pack. */
15263 /* For a function parameter pack that does not occur at the
15264 end of the parameter-declaration-list, the type of the
15265 parameter pack is a non-deduced context. */
15274 }
15279 {
15280 /* Unify the remaining arguments with the pack expansion type. */
15281 tree argvec;
15284 /* Allocate a TREE_VEC and copy in all of the arguments */
15289 /* Copy the parameter into parmvec. */
15295 /* Advance to the end of the list of parameters. */
15297 }
15299 /* Fail if we've reached the end of the parm list, and more args
15300 are present, and the parm list isn't variadic. */
15303 /* Fail if parms are left and they don't have default values. */
15306 {
15310 {
15311 count++;
15313 }
15315 }
15318 {
15319 tsubst_flags_t complain = (explain_p
15320 ? tf_warning_or_error
15323 /* Check to see if we need another pass before we start clearing
15324 ARGUMENT_PACK_INCOMPLETE_P. */
15326 {
15334 /* If this is an undeduced nontype parameter that depends on
15335 a type parameter, try another pass; its type may have been
15336 deduced from a later argument than the one from which
15337 this parameter can be deduced. */
15342 }
15345 {
15349 /* Clear the "incomplete" flags on all argument packs now so that
15350 substituting them into later default arguments works. */
15352 {
15355 }
15361 /* Core issue #226 (C++0x) [temp.deduct]:
15363 If a template argument has not been deduced, its
15364 default template argument, if any, is used.
15366 When we are in C++98 mode, TREE_PURPOSE will either
15367 be NULL_TREE or ERROR_MARK_NODE, so we do not need
15368 to explicitly check cxx_dialect here. */
15370 {
15382 else
15383 {
15385 /* The position of the first default template argument,
15386 is also the number of non-defaulted arguments in TARGS.
15387 Record that. */
15391 }
15392 }
15394 /* If the type parameter is a parameter pack, then it will
15395 be deduced to an empty parameter pack. */
15397 {
15398 tree arg;
15401 {
15405 }
15406 else
15413 }
15416 }
15417 }
15418 #ifdef ENABLE_CHECKING
15421 #endif
15424 }
15426 /* Subroutine of type_unification_real. Args are like the variables
15427 at the call site. ARG is an overloaded function (or template-id);
15428 we try deducing template args from each of the overloads, and if
15429 only one succeeds, we go with that. Modifies TARGS and returns
15430 true on success. */
15432 static bool
15434 tree targs,
15435 tree parm,
15436 tree arg,
15437 unification_kind_t strict,
15440 {
15447 {
15450 }
15451 else
15455 /* Handle `&x' where `x' is some static or non-static member
15456 function name. */
15462 /* Strip baselink information. */
15467 {
15468 /* If we got some explicit template args, we need to plug them into
15469 the affected templates before we try to unify, in case the
15470 explicit args will completely resolve the templates in question. */
15477 {
15490 {
15495 {
15498 }
15499 }
15502 }
15503 /* If no templates (or more than one) are fully resolved by the
15504 explicit arguments, this template-id is a non-deduced context; it
15505 could still be OK if we deduce all template arguments for the
15506 enclosing call through other arguments. */
15509 }
15512 /* If ARG is, for example, "(0, &f)" then its type will be unknown
15513 -- but the deduction does not succeed because the expression is
15514 not just the function on its own. */
15516 else
15522 {
15525 }
15527 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15528 to function or pointer to member function argument if the set of
15529 overloaded functions does not contain function templates and at most
15530 one of a set of overloaded functions provides a unique match.
15532 So if we found multiple possibilities, we return success but don't
15533 deduce anything. */
15536 {
15541 }
15546 }
15548 /* Core DR 115: In contexts where deduction is done and fails, or in
15549 contexts where deduction is not done, if a template argument list is
15550 specified and it, along with any default template arguments, identifies
15551 a single function template specialization, then the template-id is an
15552 lvalue for the function template specialization. */
15554 tree
15556 {
15569 {
15572 }
15574 {
15577 }
15579 {
15582 }
15585 {
15589 /* If we got some explicit template args, we need to plug them into
15590 the affected templates before we try to unify, in case the
15591 explicit args will completely resolve the templates in question. */
15599 {
15612 {
15615 {
15618 }
15620 {
15623 }
15624 }
15625 }
15627 {
15635 {
15636 tree base
15639 }
15643 }
15645 /* There were no good options and at least one bad one, so let the
15646 user know what the problem is. */
15648 }
15650 }
15652 /* Subroutine of resolve_overloaded_unification; does deduction for a single
15653 overload. Fills TARGS with any deduced arguments, or error_mark_node if
15654 different overloads deduce different arguments for a given parm.
15655 ADDR_P is true if the expression for which deduction is being
15656 performed was of the form "& fn" rather than simply "fn".
15658 Returns 1 on success. */
15660 static int
15662 tree orig_targs,
15663 tree targs,
15664 tree parm,
15665 tree arg,
15666 unification_kind_t strict,
15670 {
15672 tree tempargs;
15678 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15679 to function or pointer to member function argument if the set of
15680 overloaded functions does not contain function templates and at most
15681 one of a set of overloaded functions provides a unique match.
15683 So if this is a template, just return success. */
15695 /* We don't copy orig_targs for this because if we have already deduced
15696 some template args from previous args, unify would complain when we
15697 try to deduce a template parameter for the same argument, even though
15698 there isn't really a conflict. */
15705 /* First make sure we didn't deduce anything that conflicts with
15706 explicitly specified args. */
15708 {
15715 /* Since we're unifying against ourselves, we will fill in
15716 template args used in the function parm list with our own
15717 template parms. Discard them. */
15721 }
15724 {
15729 }
15732 }
15734 /* PARM is a template class (perhaps with unbound template
15735 parameters). ARG is a fully instantiated type. If ARG can be
15736 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
15737 TARGS are as for unify. */
15739 static tree
15742 {
15743 tree copy_of_targs;
15750 /* We need to make a new template argument vector for the call to
15751 unify. If we used TARGS, we'd clutter it up with the result of
15752 the attempted unification, even if this class didn't work out.
15753 We also don't want to commit ourselves to all the unifications
15754 we've already done, since unification is supposed to be done on
15755 an argument-by-argument basis. In other words, consider the
15756 following pathological case:
15758 template <int I, int J, int K>
15759 struct S {};
15761 template <int I, int J>
15762 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
15764 template <int I, int J, int K>
15765 void f(S<I, J, K>, S<I, I, I>);
15767 void g() {
15768 S<0, 0, 0> s0;
15769 S<0, 1, 2> s2;
15771 f(s0, s2);
15772 }
15774 Now, by the time we consider the unification involving `s2', we
15775 already know that we must have `f<0, 0, 0>'. But, even though
15776 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
15777 because there are two ways to unify base classes of S<0, 1, 2>
15778 with S<I, I, I>. If we kept the already deduced knowledge, we
15779 would reject the possibility I=1. */
15782 /* If unification failed, we're done. */
15788 }
15790 /* Given a template type PARM and a class type ARG, find the unique
15791 base type in ARG that is an instance of PARM. We do not examine
15792 ARG itself; only its base-classes. If there is not exactly one
15793 appropriate base class, return NULL_TREE. PARM may be the type of
15794 a partial specialization, as well as a plain template type. Used
15795 by unify. */
15797 static enum template_base_result
15800 {
15802 tree binfo;
15808 {
15809 /* The type could not be completed. */
15812 }
15814 /* Walk in inheritance graph order. The search order is not
15815 important, and this avoids multiple walks of virtual bases. */
15817 {
15822 {
15823 /* If there is more than one satisfactory baseclass, then:
15825 [temp.deduct.call]
15827 If they yield more than one possible deduced A, the type
15828 deduction fails.
15830 applies. */
15832 {
15835 }
15838 }
15839 }
15843 }
15845 /* Returns the level of DECL, which declares a template parameter. */
15847 static int
15849 {
15851 {
15861 }
15863 }
15865 /* Decide whether ARG can be unified with PARM, considering only the
15866 cv-qualifiers of each type, given STRICT as documented for unify.
15867 Returns nonzero iff the unification is OK on that basis. */
15869 static int
15871 {
15877 {
15878 /* Although a CVR qualifier is ignored when being applied to a
15879 substituted template parameter ([8.3.2]/1 for example), that
15880 does not allow us to unify "const T" with "int&" because both
15881 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
15882 It is ok when we're allowing additional CV qualifiers
15883 at the outer level [14.8.2.1]/3,1st bullet. */
15893 }
15904 }
15906 /* Determines the LEVEL and INDEX for the template parameter PARM. */
15907 void
15909 {
15913 {
15916 }
15917 else
15918 {
15921 }
15922 }
15924 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
15925 do { \
15926 if (unify (TP, TA, P, A, S, EP)) \
15927 return 1; \
15928 } while (0);
15930 /* Unifies the remaining arguments in PACKED_ARGS with the pack
15931 expansion at the end of PACKED_PARMS. Returns 0 if the type
15932 deduction succeeds, 1 otherwise. STRICT is the same as in
15933 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
15934 call argument list. We'll need to adjust the arguments to make them
15935 types. SUBR tells us if this is from a recursive call to
15936 type_unification_real, or for comparing two template argument
15937 lists. */
15939 static int
15943 {
15944 tree parm
15951 /* Determine the parameter packs we will be deducing from the
15952 pattern, and record their current deductions. */
15955 {
15959 /* Determine the index and level of this parameter pack. */
15962 /* Keep track of the parameter packs and their corresponding
15963 argument packs. */
15966 }
15968 /* Loop through all of the arguments that have not yet been
15969 unified and unify each with the pattern. */
15971 {
15972 tree parm;
15976 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
15977 or the element of its argument pack at the current index if
15978 this argument was explicitly specified. */
15980 {
15989 {
15992 }
15994 }
15996 /* If we had explicit template arguments, substitute them into the
15997 pattern before deduction. */
15999 {
16000 /* Some arguments might still be unspecified or dependent. */
16008 NULL_TREE);
16013 }
16014 else
16017 /* Unify the pattern with the current argument. */
16022 /* For each parameter pack, collect the deduced value. */
16024 {
16030 }
16031 }
16033 /* Verify that the results of unification with the parameter packs
16034 produce results consistent with what we've seen before, and make
16035 the deduced argument packs available. */
16037 {
16044 /* By default keep the original deduced argument pack.
16045 If necessary, more specific code is going to update the
16046 resulting deduced argument later down in this function. */
16050 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
16051 actually deduce anything. */
16059 {
16060 /* If we had fewer function args than explicit template args,
16061 just use the explicits. */
16066 }
16069 {
16070 tree result;
16071 /* Build the deduced *_ARGUMENT_PACK. */
16073 {
16078 }
16079 else
16084 /* Note the deduced argument packs for this parameter
16085 pack. */
16087 }
16091 {
16092 /* We only had the explicitly-provided arguments before, but
16093 now we have a complete set of arguments. */
16099 }
16100 else
16101 {
16107 /* Inconsistent unification of this parameter pack. */
16109 bad_old_arg,
16110 bad_new_arg);
16111 }
16112 }
16115 }
16117 /* Deduce the value of template parameters. TPARMS is the (innermost)
16118 set of template parameters to a template. TARGS is the bindings
16119 for those template parameters, as determined thus far; TARGS may
16120 include template arguments for outer levels of template parameters
16121 as well. PARM is a parameter to a template function, or a
16122 subcomponent of that parameter; ARG is the corresponding argument.
16123 This function attempts to match PARM with ARG in a manner
16124 consistent with the existing assignments in TARGS. If more values
16125 are deduced, then TARGS is updated.
16127 Returns 0 if the type deduction succeeds, 1 otherwise. The
16128 parameter STRICT is a bitwise or of the following flags:
16130 UNIFY_ALLOW_NONE:
16131 Require an exact match between PARM and ARG.
16132 UNIFY_ALLOW_MORE_CV_QUAL:
16133 Allow the deduced ARG to be more cv-qualified (by qualification
16134 conversion) than ARG.
16135 UNIFY_ALLOW_LESS_CV_QUAL:
16136 Allow the deduced ARG to be less cv-qualified than ARG.
16137 UNIFY_ALLOW_DERIVED:
16138 Allow the deduced ARG to be a template base class of ARG,
16139 or a pointer to a template base class of the type pointed to by
16140 ARG.
16141 UNIFY_ALLOW_INTEGER:
16142 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
16143 case for more information.
16144 UNIFY_ALLOW_OUTER_LEVEL:
16145 This is the outermost level of a deduction. Used to determine validity
16146 of qualification conversions. A valid qualification conversion must
16147 have const qualified pointers leading up to the inner type which
16148 requires additional CV quals, except at the outer level, where const
16149 is not required [conv.qual]. It would be normal to set this flag in
16150 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
16151 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
16152 This is the outermost level of a deduction, and PARM can be more CV
16153 qualified at this point.
16154 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
16155 This is the outermost level of a deduction, and PARM can be less CV
16156 qualified at this point. */
16158 static int
16161 {
16163 tree targ;
16164 tree tparm;
16167 /* I don't think this will do the right thing with respect to types.
16168 But the only case I've seen it in so far has been array bounds, where
16169 signedness is the only information lost, and I think that will be
16170 okay. */
16178 /* We can't deduce anything from this, but we might get all the
16179 template args from other function args. */
16182 /* If PARM uses template parameters, then we can't bail out here,
16183 even if ARG == PARM, since we won't record unifications for the
16184 template parameters. We might need them if we're trying to
16185 figure out which of two things is more specialized. */
16189 /* Handle init lists early, so the rest of the function can assume
16190 we're dealing with a type. */
16192 {
16197 /* Replace T with std::initializer_list<T> for deduction. */
16203 /* We can only deduce from an initializer list argument if the
16204 parameter is std::initializer_list; otherwise this is a
16205 non-deduced context. */
16211 {
16218 {
16220 /* It should only be possible to get here for a call. */
16222 elt_strict |= maybe_adjust_types_for_deduction
16225 }
16228 explain_p);
16229 }
16231 /* If the std::initializer_list<T> deduction worked, replace the
16232 deduced A with std::initializer_list<A>. */
16234 {
16239 }
16241 }
16243 /* Immediately reject some pairs that won't unify because of
16244 cv-qualification mismatches. */
16247 /* It is the elements of the array which hold the cv quals of an array
16248 type, and the elements might be template type parms. We'll check
16249 when we recurse. */
16251 /* We check the cv-qualifiers when unifying with template type
16252 parameters below. We want to allow ARG `const T' to unify with
16253 PARM `T' for example, when computing which of two templates
16254 is more specialized, for example. */
16268 {
16272 /* In a type which contains a nested-name-specifier, template
16273 argument values cannot be deduced for template parameters used
16274 within the nested-name-specifier. */
16286 /* The PARM is not one we're trying to unify. Just check
16287 to see if it matches ARG. */
16288 {
16293 else
16295 }
16302 /* Check for mixed types and values. */
16310 {
16311 /* ARG must be constructed from a template class or a template
16312 template parameter. */
16317 {
16321 tree parm_parms
16322 = DECL_INNERMOST_TEMPLATE_PARMS
16327 /* The resolution to DR150 makes clear that default
16328 arguments for an N-argument may not be used to bind T
16329 to a template template parameter with fewer than N
16330 parameters. It is not safe to permit the binding of
16331 default arguments as an extension, as that may change
16332 the meaning of a conforming program. Consider:
16334 struct Dense { static const unsigned int dim = 1; };
16336 template <template <typename> class View,
16337 typename Block>
16338 void operator+(float, View<Block> const&);
16340 template <typename Block,
16341 unsigned int Dim = Block::dim>
16342 struct Lvalue_proxy { operator float() const; };
16344 void
16345 test_1d (void) {
16346 Lvalue_proxy<Dense> p;
16347 float b;
16348 b + p;
16349 }
16351 Here, if Lvalue_proxy is permitted to bind to View, then
16352 the global operator+ will be used; if they are not, the
16353 Lvalue_proxy will be converted to float. */
16355 full_argvec,
16357 (explain_p
16358 ? tf_warning_or_error
16365 /* Deduce arguments T, i from TT<T> or TT<i>.
16366 We check each element of PARMVEC and ARGVEC individually
16367 rather than the whole TREE_VEC since they can have
16368 different number of elements. */
16375 /* Check if the parameters end in a pack, making them
16376 variadic. */
16386 {
16391 }
16396 DEDUCE_EXACT,
16399 }
16402 /* Fall through to deduce template name. */
16403 }
16407 {
16408 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
16410 /* Simple cases: Value already set, does match or doesn't. */
16415 }
16416 else
16417 {
16418 /* If PARM is `const T' and ARG is only `int', we don't have
16419 a match unless we are allowing additional qualification.
16420 If ARG is `const int' and PARM is just `T' that's OK;
16421 that binds `const int' to `T'. */
16426 /* Consider the case where ARG is `const volatile int' and
16427 PARM is `const T'. Then, T should be `volatile int'. */
16428 arg = cp_build_qualified_type_real
16433 /* Simple cases: Value already set, does match or doesn't. */
16439 /* Make sure that ARG is not a variable-sized array. (Note
16440 that were talking about variable-sized arrays (like
16441 `int[n]'), rather than arrays of unknown size (like
16442 `int[]').) We'll get very confused by such a type since
16443 the bound of the array is not constant, and therefore
16444 not mangleable. Besides, such types are not allowed in
16445 ISO C++, so we can do as we please here. We do allow
16446 them for 'auto' deduction, since that isn't ABI-exposed. */
16450 /* Strip typedefs as in convert_template_argument. */
16452 }
16454 /* If ARG is a parameter pack or an expansion, we cannot unify
16455 against it unless PARM is also a parameter pack. */
16460 /* If the argument deduction results is a METHOD_TYPE,
16461 then there is a problem.
16462 METHOD_TYPE doesn't map to any real C++ type the result of
16463 the deduction can not be of that type. */
16477 {
16478 /* The PARM is not one we're trying to unify. Just check
16479 to see if it matches ARG. */
16485 }
16491 {
16496 }
16498 /* [temp.deduct.type] If, in the declaration of a function template
16499 with a non-type template-parameter, the non-type
16500 template-parameter is used in an expression in the function
16501 parameter-list and, if the corresponding template-argument is
16502 deduced, the template-argument type shall match the type of the
16503 template-parameter exactly, except that a template-argument
16504 deduced from an array bound may be of any integral type.
16505 The non-type parameter might use already deduced type parameters. */
16508 /* Template-parameter dependent expression. Just accept it for now.
16509 It will later be processed in convert_template_argument. */
16510 ;
16516 /* Convert the ARG to the type of PARM; the deduced non-type
16517 template argument must exactly match the types of the
16518 corresponding parameter. */
16521 /* We haven't deduced the type of this parameter yet. Try again
16522 later. */
16524 else
16527 /* If ARG is a parameter pack or an expansion, we cannot unify
16528 against it unless PARM is also a parameter pack. */
16538 {
16539 /* A pointer-to-member constant can be unified only with
16540 another constant. */
16544 /* Just unify the class member. It would be useless (and possibly
16545 wrong, depending on the strict flags) to unify also
16546 PTRMEM_CST_CLASS, because we want to be sure that both parm and
16547 arg refer to the same variable, even if through different
16548 classes. For instance:
16550 struct A { int x; };
16551 struct B : A { };
16553 Unification of &A::x and &B::x must succeed. */
16556 }
16559 {
16563 /* [temp.deduct.call]
16565 A can be another pointer or pointer to member type that can
16566 be converted to the deduced A via a qualification
16567 conversion (_conv.qual_).
16569 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
16570 This will allow for additional cv-qualification of the
16571 pointed-to types if appropriate. */
16574 /* The derived-to-base conversion only persists through one
16575 level of pointers. */
16580 }
16595 {
16596 tree parm_max;
16597 tree arg_max;
16601 /* Our representation of array types uses "N - 1" as the
16602 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
16603 not an integer constant. We cannot unify arbitrarily
16604 complex expressions, so we eliminate the MINUS_EXPRs
16605 here. */
16609 {
16612 }
16616 {
16617 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
16618 trying to unify the type of a variable with the type
16619 of a template parameter. For example:
16621 template <unsigned int N>
16622 void f (char (&) [N]);
16623 int g();
16624 void h(int i) {
16625 char a[g(i)];
16626 f(a);
16627 }
16629 Here, the type of the ARG will be "int [g(i)]", and
16630 may be a SAVE_EXPR, etc. */
16634 }
16636 /* If only one of the bounds used a MINUS_EXPR, compensate
16637 by adding one to the other bound. */
16640 integer_type_node,
16641 parm_max,
16642 integer_one_node);
16645 integer_type_node,
16646 arg_max,
16647 integer_one_node);
16651 }
16666 /* We have already checked cv-qualification at the top of the
16667 function. */
16671 /* As far as unification is concerned, this wins. Later checks
16672 will invalidate it if necessary. */
16675 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
16676 /* Type INTEGER_CST can come from ordinary constant template args. */
16688 {
16698 /* Check for pack expansions in the parameters. */
16700 {
16702 {
16704 /* We can unify against something with a trailing
16705 parameter pack. */
16707 else
16708 /* [temp.deduct.type]/9: If the template argument list of
16709 P contains a pack expansion that is not the last
16710 template argument, the entire template argument list
16711 is a non-deduced context. */
16713 }
16714 }
16716 /* If we don't have enough arguments to satisfy the parameters
16717 (not counting the pack expression at the end), or we have
16718 too many arguments for a parameter list that doesn't end in
16719 a pack expression, we can't unify. */
16725 /* Unify all of the parameters that precede the (optional)
16726 pack expression. */
16728 {
16733 }
16736 DEDUCE_EXACT,
16739 }
16747 {
16755 }
16758 {
16762 {
16763 /* First, we try to unify the PARM and ARG directly. */
16768 {
16769 /* Fallback to the special case allowed in
16770 [temp.deduct.call]:
16772 If P is a class, and P has the form
16773 template-id, then A can be a derived class of
16774 the deduced A. Likewise, if P is a pointer to
16775 a class of the form template-id, A can be a
16776 pointer to a derived class pointed to by the
16777 deduced A. */
16784 }
16785 }
16789 /* Perhaps PARM is something like S<U> and ARG is S<int>.
16790 Then, we should unify `int' and `U'. */
16792 else
16793 /* There's no chance of unification succeeding. */
16798 }
16805 {
16808 tree a;
16814 /* CV qualifications for methods can never be deduced, they must
16815 match exactly. We need to check them explicitly here,
16816 because type_unification_real treats them as any other
16817 cv-qualified parameter. */
16819 && (!check_cv_quals_for_unify
16839 }
16842 /* Unify a pointer to member with a pointer to member function, which
16843 deduces the type of the member as a function type. */
16845 {
16846 tree method_type;
16847 tree fntype;
16849 /* Check top-level cv qualifiers */
16857 /* Determine the type of the function we are unifying against. */
16859 fntype =
16863 /* Extract the cv-qualifiers of the member function from the
16864 implicit object parameter and place them on the function
16865 type to be restored later. */
16868 }
16887 /* Matched cases are handled by the ARG == PARM test above. */
16891 /* A non-type template parameter that is a variable should be a
16892 an integral constant, in which case, it whould have been
16893 folded into its (constant) value. So we should not be getting
16894 a variable here. */
16905 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
16906 or UNDERLYING_TYPE nodes. */
16910 /* Unification fails if we hit an error node. */
16914 /* An unresolved overload is a nondeduced context. */
16919 /* We must be looking at an expression. This can happen with
16920 something like:
16922 template <int I>
16923 void foo(S<I>, S<I + 2>);
16925 This is a "nondeduced context":
16927 [deduct.type]
16929 The nondeduced contexts are:
16931 --A type that is a template-id in which one or more of
16932 the template-arguments is an expression that references
16933 a template-parameter.
16935 In these cases, we assume deduction succeeded, but don't
16936 actually infer any unifications. */
16941 else
16943 }
16944 }
16945 #undef RECUR_AND_CHECK_FAILURE
16946 \f
16947 /* Note that DECL can be defined in this translation unit, if
16948 required. */
16950 static void
16952 {
16953 tree clone;
16957 }
16959 /* Called if RESULT is explicitly instantiated, or is a member of an
16960 explicitly instantiated class. */
16962 void
16964 {
16967 /* If this entity has already been written out, it's too late to
16968 make any modifications. */
16973 /* The TREE_PUBLIC flag for function declarations will have been
16974 set correctly by tsubst. */
16977 /* This might have been set by an earlier implicit instantiation. */
16982 else
16983 {
16985 /* Always make artificials weak. */
16988 /* For WIN32 we also want to put explicit instantiations in
16989 linkonce sections. */
16992 }
16994 /* If EXTERN_P, then this function will not be emitted -- unless
16995 followed by an explicit instantiation, at which point its linkage
16996 will be adjusted. If !EXTERN_P, then this function will be
16997 emitted here. In neither circumstance do we want
16998 import_export_decl to adjust the linkage. */
17000 }
17002 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
17003 important template arguments. If any are missing, we check whether
17004 they're important by using error_mark_node for substituting into any
17005 args that were used for partial ordering (the ones between ARGS and END)
17006 and seeing if it bubbles up. */
17008 static bool
17010 {
17015 {
17018 }
17020 {
17024 }
17026 }
17028 /* Given two function templates PAT1 and PAT2, return:
17030 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
17031 -1 if PAT2 is more specialized than PAT1.
17032 0 if neither is more specialized.
17034 LEN indicates the number of parameters we should consider
17035 (defaulted parameters should not be considered).
17037 The 1998 std underspecified function template partial ordering, and
17038 DR214 addresses the issue. We take pairs of arguments, one from
17039 each of the templates, and deduce them against each other. One of
17040 the templates will be more specialized if all the *other*
17041 template's arguments deduce against its arguments and at least one
17042 of its arguments *does* *not* deduce against the other template's
17043 corresponding argument. Deduction is done as for class templates.
17044 The arguments used in deduction have reference and top level cv
17045 qualifiers removed. Iff both arguments were originally reference
17046 types *and* deduction succeeds in both directions, the template
17047 with the more cv-qualified argument wins for that pairing (if
17048 neither is more cv-qualified, they both are equal). Unlike regular
17049 deduction, after all the arguments have been deduced in this way,
17050 we do *not* verify the deduced template argument values can be
17051 substituted into non-deduced contexts.
17053 The logic can be a bit confusing here, because we look at deduce1 and
17054 targs1 to see if pat2 is at least as specialized, and vice versa; if we
17055 can find template arguments for pat1 to make arg1 look like arg2, that
17056 means that arg2 is at least as specialized as arg1. */
17058 int
17060 {
17073 /* Remove the this parameter from non-static member functions. If
17074 one is a non-static member function and the other is not a static
17075 member function, remove the first parameter from that function
17076 also. This situation occurs for operator functions where we
17077 locate both a member function (with this pointer) and non-member
17078 operator (with explicit first operand). */
17080 {
17085 }
17087 {
17090 {
17091 len--;
17093 }
17094 }
17096 /* If only one is a conversion operator, they are unordered. */
17100 /* Consider the return type for a conversion function */
17102 {
17105 len++;
17106 }
17108 processing_template_decl++;
17114 /* Stop when an ellipsis is seen. */
17116 {
17125 {
17126 /* When both arguments are pack expansions, we need only
17127 unify the patterns themselves. */
17131 /* This is the last comparison we need to do. */
17133 }
17136 {
17139 }
17142 {
17145 }
17151 {
17157 /* Setup the parameter vector, which contains only ARG1. */
17160 /* Setup the argument vector, which contains the remaining
17161 arguments. */
17170 /* We cannot deduce in the other direction, because ARG1 is
17171 a pack expansion but ARG2 is not. */
17173 }
17175 {
17181 /* Setup the parameter vector, which contains only ARG1. */
17184 /* Setup the argument vector, which contains the remaining
17185 arguments. */
17194 /* We cannot deduce in the other direction, because ARG2 is
17195 a pack expansion but ARG1 is not.*/
17197 }
17199 else
17200 {
17201 /* The normal case, where neither argument is a pack
17202 expansion. */
17209 }
17211 /* If we couldn't deduce arguments for tparms1 to make arg1 match
17212 arg2, then arg2 is not as specialized as arg1. */
17218 /* "If, for a given type, deduction succeeds in both directions
17219 (i.e., the types are identical after the transformations above)
17220 and if the type from the argument template is more cv-qualified
17221 than the type from the parameter template (as described above)
17222 that type is considered to be more specialized than the other. If
17223 neither type is more cv-qualified than the other then neither type
17224 is more specialized than the other." */
17228 {
17233 }
17236 /* We've failed to deduce something in either direction.
17237 These must be unordered. */
17242 /* We have already processed all of the arguments in our
17243 handing of the pack expansion type. */
17248 }
17250 /* "In most cases, all template parameters must have values in order for
17251 deduction to succeed, but for partial ordering purposes a template
17252 parameter may remain without a value provided it is not used in the
17253 types being used for partial ordering."
17255 Thus, if we are missing any of the targs1 we need to substitute into
17256 origs1, then pat2 is not as specialized as pat1. This can happen when
17257 there is a nondeduced context. */
17263 processing_template_decl--;
17265 /* All things being equal, if the next argument is a pack expansion
17266 for one function but not for the other, prefer the
17267 non-variadic function. FIXME this is bogus; see c++/41958. */
17271 {
17274 }
17280 else
17282 }
17284 /* Determine which of two partial specializations of MAIN_TMPL is more
17285 specialized.
17287 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
17288 to the first partial specialization. The TREE_VALUE is the
17289 innermost set of template parameters for the partial
17290 specialization. PAT2 is similar, but for the second template.
17292 Return 1 if the first partial specialization is more specialized;
17293 -1 if the second is more specialized; 0 if neither is more
17294 specialized.
17296 See [temp.class.order] for information about determining which of
17297 two templates is more specialized. */
17299 static int
17301 {
17302 tree targs;
17310 /* Just like what happens for functions, if we are ordering between
17311 different class template specializations, we may encounter dependent
17312 types in the arguments, and we need our dependency check functions
17313 to behave correctly. */
17319 {
17322 }
17328 {
17331 }
17334 /* In the case of a tie where at least one of the class templates
17335 has a parameter pack at the end, the template with the most
17336 non-packed parameters wins. */
17338 && any_deductions
17341 {
17347 /* We don't count the pack expansion at the end. */
17357 }
17360 }
17362 /* Return the template arguments that will produce the function signature
17363 DECL from the function template FN, with the explicit template
17364 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
17365 also match. Return NULL_TREE if no satisfactory arguments could be
17366 found. */
17368 static tree
17370 {
17374 tree decl_arg_types;
17377 tree arg;
17381 /* Never do unification on the 'this' parameter. */
17401 }
17403 /* Return the innermost template arguments that, when applied to a partial
17404 specialization of MAIN_TMPL whose innermost template parameters are
17405 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
17406 ARGS.
17408 For example, suppose we have:
17410 template <class T, class U> struct S {};
17411 template <class T> struct S<T*, int> {};
17413 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
17414 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
17415 int}. The resulting vector will be {double}, indicating that `T'
17416 is bound to `double'. */
17418 static tree
17420 {
17422 tree deduced_args;
17423 tree innermost_deduced_args;
17427 {
17431 innermost_deduced_args);
17432 }
17433 else
17446 /* Verify that nondeduced template arguments agree with the type
17447 obtained from argument deduction.
17449 For example:
17451 struct A { typedef int X; };
17452 template <class T, class U> struct C {};
17453 template <class T> struct C<T, typename T::X> {};
17455 Then with the instantiation `C<A, int>', we can deduce that
17456 `T' is `A' but unify () does not check whether `typename T::X'
17457 is `int'. */
17463 /* We only need to check the innermost arguments; the other
17464 arguments will always agree. */
17469 /* Now that we have bindings for all of the template arguments,
17470 ensure that the arguments deduced for the template template
17471 parameters have compatible template parameter lists. See the use
17472 of template_template_parm_bindings_ok_p in fn_type_unification
17473 for more information. */
17478 }
17480 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
17481 Return the TREE_LIST node with the most specialized template, if
17482 any. If there is no most specialized template, the error_mark_node
17483 is returned.
17485 Note that this function does not look at, or modify, the
17486 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
17487 returned is one of the elements of INSTANTIATIONS, callers may
17488 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
17489 and retrieve it from the value returned. */
17491 tree
17493 {
17500 {
17506 fate--;
17511 fate++;
17516 {
17517 /* Equally specialized, move to next function. If there
17518 is no next function, nothing's most specialized. */
17523 }
17524 }
17527 /* Now verify that champ is better than everything earlier in the
17528 instantiation list. */
17536 {
17539 }
17541 processing_template_decl--;
17547 }
17549 /* If DECL is a specialization of some template, return the most
17550 general such template. Otherwise, returns NULL_TREE.
17552 For example, given:
17554 template <class T> struct S { template <class U> void f(U); };
17556 if TMPL is `template <class U> void S<int>::f(U)' this will return
17557 the full template. This function will not trace past partial
17558 specializations, however. For example, given in addition:
17560 template <class T> struct S<T*> { template <class U> void f(U); };
17562 if TMPL is `template <class U> void S<int*>::f(U)' this will return
17563 `template <class T> template <class U> S<T*>::f(U)'. */
17565 tree
17567 {
17568 /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is
17569 an immediate specialization. */
17571 {
17575 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a
17576 template friend. */
17581 }
17583 /* Look for more and more general templates. */
17585 {
17586 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
17587 (See cp-tree.h for details.) */
17595 /* Stop if we run into an explicitly specialized class template. */
17602 }
17605 }
17607 /* Return the most specialized of the class template partial
17608 specializations of TMPL which can produce TYPE, a specialization of
17609 TMPL. The value returned is actually a TREE_LIST; the TREE_TYPE is
17610 a _TYPE node corresponding to the partial specialization, while the
17611 TREE_PURPOSE is the set of template arguments that must be
17612 substituted into the TREE_TYPE in order to generate TYPE.
17614 If the choice of partial specialization is ambiguous, a diagnostic
17615 is issued, and the error_mark_node is returned. If there are no
17616 partial specializations of TMPL matching TYPE, then NULL_TREE is
17617 returned. */
17619 static tree
17621 {
17623 tree t;
17624 tree champ;
17627 tree args;
17633 /* For determining which partial specialization to use, only the
17634 innermost args are interesting. */
17636 {
17639 }
17642 {
17643 tree partial_spec_args;
17644 tree spec_args;
17652 {
17655 /* Discard the outer levels of args, and then substitute in the
17656 template args from the enclosing class. */
17658 partial_spec_args = tsubst_template_args
17661 /* PARMS already refers to just the innermost parms, but the
17662 template parms in partial_spec_args had their levels lowered
17663 by tsubst, so we need to do the same for the parm list. We
17664 can't just tsubst the TREE_VEC itself, as tsubst wants to
17665 treat a TREE_VEC as an argument vector. */
17671 }
17673 partial_spec_args =
17676 partial_spec_args),
17687 partial_spec_args,
17688 args);
17690 {
17695 }
17696 }
17706 {
17709 ;
17710 else
17711 {
17713 {
17716 {
17719 }
17720 }
17722 }
17723 }
17727 {
17730 {
17733 }
17734 }
17737 {
17745 {
17748 }
17751 }
17754 }
17756 /* Explicitly instantiate DECL. */
17758 void
17760 {
17765 /* An error occurred, for which grokdeclarator has already issued
17766 an appropriate message. */
17769 {
17772 }
17774 {
17775 /* There is an asymmetry here in the way VAR_DECLs and
17776 FUNCTION_DECLs are handled by grokdeclarator. In the case of
17777 the latter, the DECL we get back will be marked as a
17778 template instantiation, and the appropriate
17779 DECL_TEMPLATE_INFO will be set up. This does not happen for
17780 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
17781 should handle VAR_DECLs as it currently handles
17782 FUNCTION_DECLs. */
17784 {
17787 }
17790 {
17793 }
17795 {
17800 }
17801 }
17803 {
17806 }
17807 else
17810 /* Check for various error cases. Note that if the explicit
17811 instantiation is valid the RESULT will currently be marked as an
17812 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
17813 until we get here. */
17816 {
17817 /* DR 259 [temp.spec].
17819 Both an explicit instantiation and a declaration of an explicit
17820 specialization shall not appear in a program unless the explicit
17821 instantiation follows a declaration of the explicit specialization.
17823 For a given set of template parameters, if an explicit
17824 instantiation of a template appears after a declaration of an
17825 explicit specialization for that template, the explicit
17826 instantiation has no effect. */
17828 }
17830 {
17831 /* [temp.spec]
17833 No program shall explicitly instantiate any template more
17834 than once.
17836 We check DECL_NOT_REALLY_EXTERN so as not to complain when
17837 the first instantiation was `extern' and the second is not,
17838 and EXTERN_P for the opposite case. */
17841 /* If an "extern" explicit instantiation follows an ordinary
17842 explicit instantiation, the template is instantiated. */
17845 }
17847 {
17850 }
17852 {
17855 }
17858 ;
17860 {
17863 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
17866 }
17867 else
17875 }
17877 static void
17879 {
17885 {
17888 }
17889 }
17891 /* Called from do_type_instantiation through binding_table_foreach to
17892 do recursive instantiation for the type bound in ENTRY. */
17893 static void
17895 {
17901 }
17903 /* Called from do_type_instantiation to instantiate a member
17904 (a member function or a static member variable) of an
17905 explicitly instantiated class template. */
17906 static void
17908 {
17913 }
17915 /* Perform an explicit instantiation of template class T. STORAGE, if
17916 non-null, is the RID for extern, inline or static. COMPLAIN is
17917 nonzero if this is called from the parser, zero if called recursively,
17918 since the standard is unclear (as detailed below). */
17920 void
17922 {
17932 {
17933 tree tmpl =
17937 else
17940 }
17945 {
17948 t);
17950 }
17953 {
17955 {
17957 {
17960 "ISO C++ 1998 forbids the use of %<extern%> on "
17962 }
17963 else
17965 "ISO C++ forbids the use of %qE"
17967 }
17975 else
17976 {
17978 storage);
17980 }
17981 }
17984 {
17985 /* DR 259 [temp.spec].
17987 Both an explicit instantiation and a declaration of an explicit
17988 specialization shall not appear in a program unless the explicit
17989 instantiation follows a declaration of the explicit specialization.
17991 For a given set of template parameters, if an explicit
17992 instantiation of a template appears after a declaration of an
17993 explicit specialization for that template, the explicit
17994 instantiation has no effect. */
17996 }
17998 {
17999 /* [temp.spec]
18001 No program shall explicitly instantiate any template more
18002 than once.
18004 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
18005 instantiation was `extern'. If EXTERN_P then the second is.
18006 These cases are OK. */
18013 /* If we've already instantiated the template, just return now. */
18016 }
18024 {
18025 tree tmp;
18027 /* In contrast to implicit instantiation, where only the
18028 declarations, and not the definitions, of members are
18029 instantiated, we have here:
18031 [temp.explicit]
18033 The explicit instantiation of a class template specialization
18034 implies the instantiation of all of its members not
18035 previously explicitly specialized in the translation unit
18036 containing the explicit instantiation.
18038 Of course, we can't instantiate member template classes, since
18039 we don't have any arguments for them. Note that the standard
18040 is unclear on whether the instantiation of the members are
18041 *explicit* instantiations or not. However, the most natural
18042 interpretation is that it should be an explicit instantiation. */
18057 }
18058 }
18060 /* Given a function DECL, which is a specialization of TMPL, modify
18061 DECL to be a re-instantiation of TMPL with the same template
18062 arguments. TMPL should be the template into which tsubst'ing
18063 should occur for DECL, not the most general template.
18065 One reason for doing this is a scenario like this:
18067 template <class T>
18068 void f(const T&, int i);
18070 void g() { f(3, 7); }
18072 template <class T>
18073 void f(const T& t, const int i) { }
18075 Note that when the template is first instantiated, with
18076 instantiate_template, the resulting DECL will have no name for the
18077 first parameter, and the wrong type for the second. So, when we go
18078 to instantiate the DECL, we regenerate it. */
18080 static void
18082 {
18083 /* The arguments used to instantiate DECL, from the most general
18084 template. */
18085 tree args;
18086 tree code_pattern;
18091 /* Make sure that we can see identifiers, and compute access
18092 correctly. */
18096 {
18097 tree decl_parm;
18098 tree pattern_parm;
18099 tree specs;
18113 specs);
18115 /* Merge parameter declarations. */
18118 pattern_parm
18122 {
18123 tree parm_type;
18124 tree attributes;
18129 NULL_TREE);
18135 {
18138 }
18141 }
18142 /* Merge any parameters that match with the function parameter
18143 pack. */
18145 {
18147 tree expanded_types;
18148 /* Expand the TYPE_PACK_EXPANSION that provides the types for
18149 the parameters in this function parameter pack. */
18154 {
18155 tree parm_type;
18156 tree attributes;
18159 /* Rename the parameter to include the index. */
18168 {
18171 }
18173 }
18174 }
18175 /* Merge additional specifiers from the CODE_PATTERN. */
18179 }
18181 {
18189 }
18190 else
18194 }
18196 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
18197 substituted to get DECL. */
18199 tree
18201 {
18204 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
18205 for the instantiation. This is not always the most general
18206 template. Consider, for example:
18208 template <class T>
18209 struct S { template <class U> void f();
18210 template <> void f<int>(); };
18212 and an instantiation of S<double>::f<int>. We want TD to be the
18213 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
18215 more general template. */
18217 /* We must also deal with friend templates. Given:
18219 template <class T> struct S {
18220 template <class U> friend void f() {};
18221 };
18223 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
18224 so far as the language is concerned, but that's still
18225 where we get the pattern for the instantiation from. On
18226 other hand, if the definition comes outside the class, say:
18228 template <class T> struct S {
18229 template <class U> friend void f();
18230 };
18231 template <class U> friend void f() {}
18233 we don't need to look any further. That's what the check for
18234 DECL_INITIAL is for. */
18238 {
18239 /* The present template, TD, should not be a definition. If it
18240 were a definition, we should be using it! Note that we
18241 cannot restructure the loop to just keep going until we find
18242 a template with a definition, since that might go too far if
18243 a specialization was declared, but not defined. */
18247 /* Fetch the more general template. */
18249 }
18252 }
18254 /* Returns true if we need to instantiate this template instance even if we
18255 know we aren't going to emit it.. */
18257 bool
18259 {
18260 /* We always instantiate inline functions so that we can inline them. An
18261 explicit instantiation declaration prohibits implicit instantiation of
18262 non-inline functions. With high levels of optimization, we would
18263 normally inline non-inline functions -- but we're not allowed to do
18264 that for "extern template" functions. Therefore, we check
18265 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
18269 /* And we need to instantiate static data members so that
18270 their initializers are available in integral constant
18271 expressions. */
18274 }
18276 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
18277 instantiate it now, modifying TREE_TYPE (fn). */
18279 void
18281 {
18295 {
18297 {
18310 }
18311 else
18313 }
18314 else
18315 {
18316 /* This is an implicitly declared function, so NOEX is a list of
18317 other functions to evaluate and merge. */
18318 tree elt;
18321 {
18323 tree subspec;
18327 }
18328 }
18333 {
18336 else
18338 }
18339 }
18341 /* Produce the definition of D, a _DECL generated from a template. If
18342 DEFER_OK is nonzero, then we don't have to actually do the
18343 instantiation now; we just have to do it sometime. Normally it is
18344 an error if this is an explicit instantiation but D is undefined.
18345 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
18346 explicitly instantiated class template. */
18348 tree
18351 {
18353 tree gen_args;
18354 tree args;
18355 tree td;
18356 tree code_pattern;
18357 tree spec;
18358 tree gen_tmpl;
18362 tree fn_context;
18365 /* This function should only be used to instantiate templates for
18366 functions and static member variables. */
18370 /* Variables are never deferred; if instantiation is required, they
18371 are instantiated right away. That allows for better code in the
18372 case that an expression refers to the value of the variable --
18373 if the variable has a constant value the referring expression can
18374 take advantage of that fact. */
18379 /* Don't instantiate cloned functions. Instead, instantiate the
18380 functions they cloned. */
18388 /* D has already been instantiated or explicitly specialized, so
18389 there's nothing for us to do here.
18391 It might seem reasonable to check whether or not D is an explicit
18392 instantiation, and, if so, stop here. But when an explicit
18393 instantiation is deferred until the end of the compilation,
18394 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
18395 the instantiation. */
18398 /* Check to see whether we know that this template will be
18399 instantiated in some other file, as with "extern template"
18400 extension. */
18403 /* In general, we do not instantiate such templates. */
18411 /* We should already have the extra args. */
18414 /* And what's in the hash table should match D. */
18418 /* This needs to happen before any tsubsting. */
18424 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
18425 for the instantiation. */
18429 /* We should never be trying to instantiate a member of a class
18430 template or partial specialization. */
18435 /* In the case of a friend template whose definition is provided
18436 outside the class, we may have too many arguments. Drop the
18437 ones we don't need. The same is true for specializations. */
18438 args = get_innermost_template_args
18440 else
18446 else
18449 /* We may be in the middle of deferred access check. Disable it now. */
18452 /* Unless an explicit instantiation directive has already determined
18453 the linkage of D, remember that a definition is available for
18454 this entity. */
18464 /* If D is a member of an explicitly instantiated class template,
18465 and no definition is available, treat it like an implicit
18466 instantiation. */
18469 {
18470 /* Leave linkage flags alone on instantiations with anonymous
18471 visibility. */
18473 {
18476 }
18478 }
18483 /* Defer all other templates, unless we have been explicitly
18484 forbidden from doing so. */
18486 template. */
18487 ! pattern_defined
18488 /* If it's OK to postpone instantiation, do so. */
18489 || defer_ok
18490 /* If this is a static data member that will be defined
18491 elsewhere, we don't want to instantiate the entire data
18492 member, but we do want to instantiate the initializer so that
18493 we can substitute that elsewhere. */
18495 {
18496 /* The definition of the static data member is now required so
18497 we must substitute the initializer. */
18501 {
18502 tree ns;
18503 tree init;
18510 args,
18513 /* Make sure the initializer is still constant, in case of
18514 circular dependency (template/instantiate6.C). */
18515 const_init
18519 LOOKUP_ONLYCONVERTING);
18522 }
18524 /* We restore the source position here because it's used by
18525 add_pending_template. */
18531 /* [temp.explicit]
18533 The definition of a non-exported function template, a
18534 non-exported member function template, or a non-exported
18535 member function or static data member of a class template
18536 shall be present in every translation unit in which it is
18537 explicitly instantiated. */
18541 /* If we're in unevaluated context, we just wanted to get the
18542 constant value; this isn't an odr use, so don't queue
18543 a full instantiation. */
18546 /* ??? Historically, we have instantiated inline functions, even
18547 when marked as "extern template". */
18551 }
18552 /* Tell the repository that D is available in this translation unit
18553 -- and see if it is supposed to be instantiated here. */
18555 {
18556 /* In a PCH file, despite the fact that the repository hasn't
18557 requested instantiation in the PCH it is still possible that
18558 an instantiation will be required in a file that includes the
18559 PCH. */
18562 /* Instantiate inline functions so that the inliner can do its
18563 job, even though we'll not be emitting a copy of this
18564 function. */
18567 }
18576 /* Mark D as instantiated so that recursive calls to
18577 instantiate_decl do not try to instantiate it again. */
18580 /* Regenerate the declaration in case the template has been modified
18581 by a subsequent redeclaration. */
18584 /* We already set the file and line above. Reset them now in case
18585 they changed as a result of calling regenerate_decl_from_template. */
18589 {
18590 tree init;
18593 /* Clear out DECL_RTL; whatever was there before may not be right
18594 since we've reset the type of the declaration. */
18598 /* The initializer is placed in DECL_INITIAL by
18599 regenerate_decl_from_template so we don't need to
18600 push/pop_access_scope again here. Pull it out so that
18601 cp_finish_decl can process it. */
18606 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
18607 initializer. That function will defer actual emission until
18608 we have a chance to determine linkage. */
18611 /* Enter the scope of D so that access-checking works correctly. */
18616 }
18620 {
18622 tree subst_decl;
18623 tree tmpl_parm;
18624 tree spec_parm;
18626 /* Save away the current list, in case we are instantiating one
18627 template from within the body of another. */
18630 /* Set up the list of local specializations. */
18633 /* Set up context. */
18636 /* Some typedefs referenced from within the template code need to be
18637 access checked at template instantiation time, i.e now. These
18638 types were added to the template at parsing time. Let's get those
18639 and perform the access checks then. */
18641 gen_args);
18643 /* Create substitution entries for the parameters. */
18648 {
18652 }
18654 {
18656 {
18659 }
18660 else
18661 {
18662 /* Register the (value) argument pack as a specialization of
18663 TMPL_PARM, then move on. */
18666 }
18667 }
18670 /* Substitute into the body of the function. */
18675 /* Set the current input_location to the end of the function
18676 so that finish_function knows where we are. */
18679 /* We don't need the local specializations any more. */
18683 /* Finish the function. */
18686 }
18688 /* We're not deferring instantiation any more. */
18696 out:
18704 }
18706 /* Run through the list of templates that we wish we could
18707 instantiate, and instantiate any we can. RETRIES is the
18708 number of times we retry pending template instantiation. */
18710 void
18712 {
18716 /* Instantiating templates may trigger vtable generation. This in turn
18717 may require further template instantiations. We place a limit here
18718 to avoid infinite loop. */
18720 {
18724 " instantiating %q+D, possibly from virtual table generation"
18728 /* Pretend that we defined it. */
18731 }
18733 do
18734 {
18739 {
18744 {
18745 tree fn;
18748 {
18752 fn;
18760 }
18763 }
18764 else
18765 {
18768 {
18769 instantiation
18775 }
18779 }
18782 /* If INSTANTIATION has been instantiated, then we don't
18783 need to consider it again in the future. */
18785 else
18786 {
18789 }
18792 }
18794 }
18798 }
18800 /* Substitute ARGVEC into T, which is a list of initializers for
18801 either base class or a non-static data member. The TREE_PURPOSEs
18802 are DECLs, and the TREE_VALUEs are the initializer values. Used by
18803 instantiate_decl. */
18805 static tree
18807 {
18811 {
18812 tree decl;
18813 tree init;
18819 {
18820 tree expr;
18821 tree arg;
18823 /* Expand the base class expansion type into separate base
18824 classes. */
18826 tf_warning_or_error,
18827 NULL_TREE);
18831 /* We'll be building separate TREE_LISTs of arguments for
18832 each base. */
18838 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
18839 expand each argument in the TREE_VALUE of t. */
18846 /* VOID_TYPE_NODE is used to indicate
18847 value-initialization. */
18848 {
18851 }
18852 else
18853 {
18854 /* Substitute parameter packs into each argument in the
18855 TREE_LIST. */
18858 {
18859 tree expanded_exprs;
18861 /* Expand the argument. */
18863 expanded_exprs
18865 tf_warning_or_error,
18866 NULL_TREE);
18870 /* Prepend each of the expanded expressions to the
18871 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
18873 {
18878 }
18879 }
18882 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
18883 since we built them backwards. */
18885 {
18888 }
18889 }
18890 }
18893 {
18895 {
18899 }
18900 else
18901 {
18902 tree tmp;
18917 /* If we had an initializer but it instantiated to nothing,
18918 value-initialize the object. This will only occur when
18919 the initializer was a pack expansion where the parameter
18920 packs used in that expansion were of length zero. */
18923 }
18926 {
18930 }
18931 }
18932 }
18934 }
18936 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
18938 static void
18940 {
18945 else
18947 }
18949 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
18950 is the instantiation (which should have been created with
18951 start_enum) and ARGS are the template arguments to use. */
18953 static void
18955 {
18956 tree e;
18962 {
18963 tree value;
18964 tree decl;
18967 /* Note that in a template enum, the TREE_VALUE is the
18968 CONST_DECL, not the corresponding INTEGER_CST. */
18973 /* Give this enumeration constant the correct access. */
18976 /* Actually build the enumerator itself. */
18977 build_enumerator
18979 }
18989 }
18991 /* DECL is a FUNCTION_DECL that is a template specialization. Return
18992 its type -- but without substituting the innermost set of template
18993 arguments. So, innermost set of template parameters will appear in
18994 the type. */
18996 tree
18998 {
18999 tree fn_type;
19000 tree tmpl;
19001 tree targs;
19002 tree tparms;
19010 /* There should be as many levels of arguments as there are levels
19011 of parameters. */
19017 /* No substitution is necessary. */
19018 ;
19019 else
19020 {
19022 tree partial_args;
19024 /* Replace the innermost level of the TARGS with NULL_TREEs to
19025 let tsubst know not to substitute for those parameters. */
19034 /* Make sure that we can see identifiers, and compute access
19035 correctly. */
19039 /* Now, do the (partial) substitution to figure out the
19040 appropriate function type. */
19044 /* Substitute into the template parameters to obtain the real
19045 innermost set of parameters. This step is important if the
19046 innermost set of template parameters contains value
19047 parameters whose types depend on outer template parameters. */
19052 }
19055 }
19057 /* Return truthvalue if we're processing a template different from
19058 the last one involved in diagnostics. */
19059 int
19061 {
19063 }
19065 /* Remember current template involved in diagnostics. */
19066 void
19068 {
19070 }
19074 {
19076 }
19078 /* [temp.param] Check that template non-type parm TYPE is of an allowable
19079 type. Return zero for ok, nonzero for disallowed. Issue error and
19080 warning messages under control of COMPLAIN. */
19082 static int
19084 {
19101 {
19104 else
19106 type);
19107 }
19109 }
19111 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
19112 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
19114 static bool
19116 {
19117 tree scope;
19119 /* [temp.dep.type]
19121 A type is dependent if it is:
19123 -- a template parameter. Template template parameters are types
19124 for us (since TYPE_P holds true for them) so we handle
19125 them here. */
19129 /* -- a qualified-id with a nested-name-specifier which contains a
19130 class-name that names a dependent type or whose unqualified-id
19131 names a dependent type. */
19134 /* -- a cv-qualified type where the cv-unqualified type is
19135 dependent. */
19137 /* -- a compound type constructed from any dependent type. */
19147 {
19148 tree arg_type;
19153 arg_type;
19158 }
19159 /* -- an array type constructed from any dependent type or whose
19160 size is specified by a constant expression that is
19161 value-dependent.
19163 We checked for type- and value-dependence of the bounds in
19164 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
19166 {
19171 }
19173 /* -- a template-id in which either the template name is a template
19174 parameter ... */
19177 /* ... or any of the template arguments is a dependent type or
19178 an expression that is type-dependent or value-dependent. */
19180 && (any_dependent_template_arguments_p
19184 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
19185 dependent; if the argument of the `typeof' expression is not
19186 type-dependent, then it should already been have resolved. */
19192 /* A template argument pack is dependent if any of its packed
19193 arguments are. */
19195 {
19201 }
19203 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
19204 be template parameters. */
19208 /* The standard does not specifically mention types that are local
19209 to template functions or local classes, but they should be
19210 considered dependent too. For example:
19212 template <int I> void f() {
19213 enum E { a = I };
19214 S<sizeof (E)> s;
19215 }
19217 The size of `E' cannot be known until the value of `I' has been
19218 determined. Therefore, `E' must be considered dependent. */
19222 /* Don't use type_dependent_expression_p here, as it can lead
19223 to infinite recursion trying to determine whether a lambda
19224 nested in a lambda is dependent (c++/47687). */
19228 && (any_dependent_template_arguments_p
19232 /* Other types are non-dependent. */
19234 }
19236 /* Returns TRUE if TYPE is dependent, in the sense of
19237 [temp.dep.type]. Note that a NULL type is considered dependent. */
19239 bool
19241 {
19242 /* If there are no template parameters in scope, then there can't be
19243 any dependent types. */
19245 {
19246 /* If we are not processing a template, then nobody should be
19247 providing us with a dependent type. */
19251 }
19253 /* If the type is NULL, we have not computed a type for the entity
19254 in question; in that case, the type is dependent. */
19258 /* Erroneous types can be considered non-dependent. */
19262 /* If we have not already computed the appropriate value for TYPE,
19263 do so now. */
19265 {
19268 }
19271 }
19273 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
19274 lookup. In other words, a dependent type that is not the current
19275 instantiation. */
19277 bool
19279 {
19282 }
19284 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
19285 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
19286 expression. */
19288 /* Note that this predicate is not appropriate for general expressions;
19289 only constant expressions (that satisfy potential_constant_expression)
19290 can be tested for value dependence. */
19292 bool
19294 {
19298 /* A name declared with a dependent type. */
19303 {
19305 /* A name that has not been looked up -- must be dependent. */
19309 /* A non-type template parm. */
19313 /* A non-type template parm. */
19319 /* A constant with literal type and is initialized
19320 with an expression that is value-dependent.
19322 Note that a non-dependent parenthesized initializer will have
19323 already been replaced with its constant value, so if we see
19324 a TREE_LIST it must be dependent. */
19337 /* These expressions are value-dependent if the type to which
19338 the cast occurs is dependent or the expression being casted
19339 is value-dependent. */
19340 {
19346 /* A functional cast has a list of operands. */
19349 {
19350 /* If there are no operands, it must be an expression such
19351 as "int()". This should not happen for aggregate types
19352 because it would form non-constant expressions. */
19357 }
19363 }
19368 /* FALLTHRU */
19371 /* A `sizeof' expression is value-dependent if the operand is
19372 type-dependent or is a pack expansion. */
19381 /* An 'encode' expression is value-dependent if the operand is
19382 type-dependent. */
19391 /* instantiation_dependent_r treats this as dependent so that we
19392 check access at instantiation time, and all instantiation-dependent
19393 expressions should also be considered value-dependent. */
19401 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
19402 is value-dependent. */
19403 {
19412 }
19415 {
19419 }
19430 {
19434 }
19437 {
19444 {
19446 /* In a call to a constexpr member function, look through the
19447 implicit ADDR_EXPR on the object argument so that it doesn't
19448 cause the call to be considered value-dependent. We also
19449 look through it in potential_constant_expression. */
19456 }
19458 }
19461 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
19462 type-dependent. */
19466 {
19468 tree val;
19473 }
19476 /* Treat a GNU statement expression as dependent to avoid crashing
19477 under fold_non_dependent_expr; it can't be constant. */
19481 /* A constant expression is value-dependent if any subexpression is
19482 value-dependent. */
19484 {
19491 {
19495 {
19498 /* In some cases, some of the operands may be missing.l
19499 (For example, in the case of PREDECREMENT_EXPR, the
19500 amount to increment by may be missing.) That doesn't
19501 make the expression dependent. */
19504 }
19505 }
19509 }
19511 }
19513 /* The expression is not value-dependent. */
19515 }
19517 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
19518 [temp.dep.expr]. Note that an expression with no type is
19519 considered dependent. Other parts of the compiler arrange for an
19520 expression with type-dependent subexpressions to have no type, so
19521 this function doesn't have to be fully recursive. */
19523 bool
19525 {
19532 /* An unresolved name is always dependent. */
19537 /* Some expression forms are never type-dependent. */
19550 /* The types of these expressions depends only on the type to which
19551 the cast occurs. */
19560 /* The types of these expressions depends only on the type created
19561 by the expression. */
19564 {
19565 /* For NEW_EXPR tree nodes created inside a template, either
19566 the object type itself or a TREE_LIST may appear as the
19567 operand 1. */
19570 /* This is an array type. We need to check array dimensions
19571 as well. */
19573 || value_dependent_expression_p
19575 else
19577 }
19580 {
19584 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
19585 contains an identifier associated by name lookup with one or more
19586 declarations declared with a dependent type, or...a
19587 nested-name-specifier or qualified-id that names a member of an
19588 unknown specialization. */
19591 }
19596 && (any_dependent_template_arguments_p
19608 {
19609 tree elt;
19613 {
19616 }
19618 }
19620 /* A static data member of the current instantiation with incomplete
19621 array type is type-dependent, as the definition and specializations
19622 can have different bounds. */
19630 {
19635 {
19641 }
19642 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
19650 {
19655 }
19660 {
19664 }
19666 }
19671 }
19673 /* walk_tree callback function for instantiation_dependent_expression_p,
19674 below. Returns non-zero if a dependent subexpression is found. */
19676 static tree
19679 {
19681 {
19682 /* We don't have to worry about decltype currently because decltype
19683 of an instantiation-dependent expr is a dependent type. This
19684 might change depending on the resolution of DR 1172. */
19687 }
19690 {
19691 /* Don't treat an argument list as dependent just because it has no
19692 TREE_TYPE. */
19700 /* Handle expressions with type operands. */
19706 {
19711 {
19716 else
19717 {
19720 }
19721 }
19723 }
19727 /* In a template, finish_class_member_access_expr creates a
19728 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
19729 type-dependent, so that we can check access control at
19730 instantiation time (PR 42277). See also Core issue 1273. */
19735 /* Similarly, finish_qualified_id_expr builds up a SCOPE_REF in a
19736 template so that we can check access at instantiation time even
19737 though we know which member it resolves to. */
19742 }
19746 else
19748 }
19750 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
19751 sense defined by the ABI:
19753 "An expression is instantiation-dependent if it is type-dependent
19754 or value-dependent, or it has a subexpression that is type-dependent
19755 or value-dependent." */
19757 bool
19759 {
19760 tree result;
19771 }
19773 /* Like type_dependent_expression_p, but it also works while not processing
19774 a template definition, i.e. during substitution or mangling. */
19776 bool
19778 {
19784 }
19786 /* Returns TRUE if ARGS contains a type-dependent expression. */
19788 bool
19790 {
19792 tree arg;
19795 {
19798 }
19800 }
19802 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
19803 expressions) contains any type-dependent expressions. */
19805 bool
19807 {
19813 }
19815 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
19816 expressions) contains any value-dependent expressions. */
19818 bool
19820 {
19826 }
19828 /* Returns TRUE if the ARG (a template argument) is dependent. */
19830 bool
19832 {
19836 /* Assume a template argument that was wrongly written by the user
19837 is dependent. This is consistent with what
19838 any_dependent_template_arguments_p [that calls this function]
19839 does. */
19850 {
19854 {
19857 }
19860 }
19863 else
19866 }
19868 /* Returns true if ARGS (a collection of template arguments) contains
19869 any types that require structural equality testing. */
19871 bool
19873 {
19883 {
19886 {
19892 {
19893 /* Look inside the argument pack. */
19896 }
19899 {
19913 }
19914 }
19915 }
19918 }
19920 /* Returns true if ARGS (a collection of template arguments) contains
19921 any dependent arguments. */
19923 bool
19925 {
19935 {
19940 }
19943 }
19945 /* Returns TRUE if the template TMPL is dependent. */
19947 bool
19949 {
19951 {
19953 {
19957 }
19959 }
19961 /* Template template parameters are dependent. */
19965 /* So are names that have not been looked up. */
19969 /* So are member templates of dependent classes. */
19973 }
19975 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
19977 bool
19979 {
19982 }
19984 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
19985 is dependent. */
19987 bool
19989 {
19996 {
20017 {
20021 }
20025 {
20029 {
20034 }
20035 }
20036 }
20039 }
20041 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
20042 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
20043 no such TYPE can be found. Note that this function peers inside
20044 uninstantiated templates and therefore should be used only in
20045 extremely limited situations. ONLY_CURRENT_P restricts this
20046 peering to the currently open classes hierarchy (which is required
20047 when comparing types). */
20049 tree
20051 {
20052 tree scope;
20053 tree name;
20054 tree decl;
20056 tree pushed_scope;
20057 tree result;
20062 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
20063 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
20064 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
20065 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
20066 identifier of the TYPENAME_TYPE anymore.
20067 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
20068 TYPENAME_TYPE instead, we avoid messing up with a possible
20069 typedef variant case. */
20072 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
20073 it first before we can figure out what NAME refers to. */
20076 /* If we don't know what SCOPE refers to, then we cannot resolve the
20077 TYPENAME_TYPE. */
20080 /* If the SCOPE is a template type parameter, we have no way of
20081 resolving the name. */
20084 /* If the SCOPE is not the current instantiation, there's no reason
20085 to look inside it. */
20088 /* If this is a typedef, we don't want to look inside (c++/11987). */
20091 /* If SCOPE isn't the template itself, it will not have a valid
20092 TYPE_FIELDS list. */
20094 /* scope is either the template itself or a compatible instantiation
20095 like X<T>, so look up the name in the original template. */
20097 else
20098 /* scope is a partial instantiation, so we can't do the lookup or we
20099 will lose the template arguments. */
20101 /* Enter the SCOPE so that name lookup will be resolved as if we
20102 were in the class definition. In particular, SCOPE will no
20103 longer be considered a dependent type. */
20105 /* Look up the declaration. */
20107 tf_warning_or_error);
20111 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
20112 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
20117 {
20121 }
20124 {
20125 tree tmpl;
20126 tree args;
20127 /* Obtain the template and the arguments. */
20130 /* Instantiate the template. */
20136 }
20138 /* Leave the SCOPE. */
20142 /* If we failed to resolve it, return the original typename. */
20146 /* If lookup found a typename type, resolve that too. */
20148 {
20149 /* Ill-formed programs can cause infinite recursion here, so we
20150 must catch that. */
20154 }
20156 /* Qualify the resulting type. */
20162 }
20164 /* EXPR is an expression which is not type-dependent. Return a proxy
20165 for EXPR that can be used to compute the types of larger
20166 expressions containing EXPR. */
20168 tree
20170 {
20171 tree inner_expr;
20173 #ifdef ENABLE_CHECKING
20174 /* Try to get a constant value for all non-type-dependent expressions in
20175 order to expose bugs in *_dependent_expression_p and constexpr. */
20178 #endif
20180 /* Preserve OVERLOADs; the functions must be available to resolve
20181 types. */
20192 /* There is no need to return a proxy for a variable. */
20195 /* Preserve string constants; conversions from string constants to
20196 "char *" are allowed, even though normally a "const char *"
20197 cannot be used to initialize a "char *". */
20200 /* Preserve arithmetic constants, as an optimization -- there is no
20201 reason to create a new node. */
20204 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
20205 There is at least one place where we want to know that a
20206 particular expression is a throw-expression: when checking a ?:
20207 expression, there are special rules if the second or third
20208 argument is a throw-expression. */
20212 /* Don't wrap an initializer list, we need to be able to look inside. */
20216 /* Don't wrap a dummy object, we need to be able to test for it. */
20235 /* If the type is unknown, it can't really be non-dependent */
20238 /* Otherwise, build a NON_DEPENDENT_EXPR. */
20240 }
20242 /* ARGS is a vector of expressions as arguments to a function call.
20243 Replace the arguments with equivalent non-dependent expressions.
20244 This modifies ARGS in place. */
20246 void
20248 {
20250 tree arg;
20253 {
20257 }
20258 }
20260 /* Returns a type which represents 'auto'. We use a TEMPLATE_TYPE_PARM
20261 with a level one deeper than the actual template parms. */
20263 tree
20265 {
20278 }
20280 /* Given type ARG, return std::initializer_list<ARG>. */
20282 static tree
20284 {
20285 tree std_init_list = namespace_binding
20287 tree argvec;
20289 {
20293 }
20298 }
20300 /* Replace auto in TYPE with std::initializer_list<auto>. */
20302 static tree
20304 {
20311 }
20313 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
20314 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
20316 tree
20318 {
20327 /* Defining a subset of type-dependent expressions that we can deduce
20328 from ahead of time isn't worth the trouble. */
20331 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
20332 with either a new invented type template parameter U or, if the
20333 initializer is a braced-init-list (8.5.4), with
20334 std::initializer_list<U>. */
20350 {
20352 /* Try again at instantiation time. */
20355 /* If type is error_mark_node a diagnostic must have been
20356 emitted by now. Also, having a mention to '<type error>'
20357 in the diagnostic is not really useful to the user. */
20358 {
20362 else
20364 }
20366 }
20368 /* If the list of declarators contains more than one declarator, the type
20369 of each declared variable is determined as described above. If the
20370 type deduced for the template parameter U is not the same in each
20371 deduction, the program is ill-formed. */
20374 {
20380 else
20384 }
20390 }
20392 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
20393 result. */
20395 tree
20397 {
20398 tree argvec;
20405 /* For a late-specified return type in a template type-parameter, we
20406 need to add a dummy argument level for its parmlist. */
20407 argvec = add_to_template_args
20412 }
20414 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto'. */
20416 bool
20418 {
20422 else
20424 }
20426 /* Returns true iff TYPE contains a use of 'auto'. Since auto can only
20427 appear as a type-specifier for the declaration in question, we don't
20428 have to look through the whole type. */
20430 tree
20432 {
20449 }
20451 /* For a given template T, return the vector of typedefs referenced
20452 in T for which access check is needed at T instantiation time.
20453 T is either a FUNCTION_DECL or a RECORD_TYPE.
20454 Those typedefs were added to T by the function
20455 append_type_to_template_for_access_check. */
20459 {
20460 tree ti;
20471 {
20476 }
20479 }
20481 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
20482 tied to T. That list of typedefs will be access checked at
20483 T instantiation time.
20484 T is either a FUNCTION_DECL or a RECORD_TYPE.
20485 TYPE_DECL is a TYPE_DECL node representing a typedef.
20486 SCOPE is the scope through which TYPE_DECL is accessed.
20487 LOCATION is the location of the usage point of TYPE_DECL.
20489 This function is a subroutine of
20490 append_type_to_template_for_access_check. */
20492 static void
20494 tree type_decl,
20495 tree scope,
20496 location_t location)
20497 {
20498 qualified_typedef_usage_t typedef_usage;
20499 tree ti;
20506 && type_decl
20520 }
20522 /* Append TYPE_DECL to the template TEMPL.
20523 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
20524 At TEMPL instanciation time, TYPE_DECL will be checked to see
20525 if it can be accessed through SCOPE.
20526 LOCATION is the location of the usage point of TYPE_DECL.
20528 e.g. consider the following code snippet:
20530 class C
20531 {
20532 typedef int myint;
20533 };
20535 template<class U> struct S
20536 {
20537 C::myint mi; // <-- usage point of the typedef C::myint
20538 };
20540 S<char> s;
20542 At S<char> instantiation time, we need to check the access of C::myint
20543 In other words, we need to check the access of the myint typedef through
20544 the C scope. For that purpose, this function will add the myint typedef
20545 and the scope C through which its being accessed to a list of typedefs
20546 tied to the template S. That list will be walked at template instantiation
20547 time and access check performed on each typedefs it contains.
20548 Note that this particular code snippet should yield an error because
20549 myint is private to C. */
20551 void
20553 tree type_decl,
20554 tree scope,
20555 location_t location)
20556 {
20562 /* Make sure we don't append the type to the template twice. */
20569 }
20571 /* Set up the hash tables for template instantiations. */
20573 void
20575 {
20577 hash_specialization,
20578 eq_specializations,
20579 ggc_free);
20581 hash_specialization,
20582 eq_specializations,
20583 ggc_free);
20584 }
20586 /* Print stats about the template hash tables for -fstats. */
20588 void
20590 {
20599 }