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1 /* Handle parameterized types (templates) for GNU C++.
2 Copyright (C) 1992-2013 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
45 /* The type of functions taking a tree, and some additional data, and
46 returning an int. */
49 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
50 instantiations have been deferred, either because their definitions
51 were not yet available, or because we were putting off doing the work. */
55 };
70 /* Live only within one (recursive) call to tsubst_expr. We use
71 this to pass the statement expression node from the STMT_EXPR
72 to the EXPR_STMT that is its result. */
75 /* A map from local variable declarations in the body of the template
76 presently being instantiated to the corresponding instantiated
77 local variables. */
80 /* True if we've recursed into fn_type_unification too many times. */
84 {
85 tree tmpl;
86 tree args;
87 tree spec;
91 htab_t decl_specializations;
94 htab_t type_specializations;
96 /* Contains canonical template parameter types. The vector is indexed by
97 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
98 TREE_LIST, whose TREE_VALUEs contain the canonical template
99 parameters of various types and levels. */
102 #define UNIFY_ALLOW_NONE 0
103 #define UNIFY_ALLOW_MORE_CV_QUAL 1
104 #define UNIFY_ALLOW_LESS_CV_QUAL 2
105 #define UNIFY_ALLOW_DERIVED 4
106 #define UNIFY_ALLOW_INTEGER 8
107 #define UNIFY_ALLOW_OUTER_LEVEL 16
108 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
109 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
112 tbr_incomplete_type,
113 tbr_ambiguous_baseclass,
114 tbr_success
115 };
138 tree);
200 location_t);
208 /* Make the current scope suitable for access checking when we are
209 processing T. T can be FUNCTION_DECL for instantiated function
210 template, VAR_DECL for static member variable, or TYPE_DECL for
211 alias template (needed by instantiate_decl). */
213 static void
215 {
223 else
227 {
228 saved_access_scope = tree_cons
231 }
232 }
234 /* Restore the scope set up by push_access_scope. T is the node we
235 are processing. */
237 static void
239 {
241 {
244 }
248 else
250 }
252 /* Do any processing required when DECL (a member template
253 declaration) is finished. Returns the TEMPLATE_DECL corresponding
254 to DECL, unless it is a specialization, in which case the DECL
255 itself is returned. */
257 tree
259 {
266 {
267 tree type;
275 {
279 }
281 }
285 {
287 {
290 }
291 else
293 }
294 else
298 }
300 /* Create a template info node. */
302 tree
304 {
309 }
311 /* Return the template info node corresponding to T, whatever T is. */
313 tree
315 {
333 }
335 /* Returns the template nesting level of the indicated class TYPE.
337 For example, in:
338 template <class T>
339 struct A
340 {
341 template <class U>
342 struct B {};
343 };
345 A<T>::B<U> has depth two, while A<T> has depth one.
346 Both A<T>::B<int> and A<int>::B<U> have depth one, if
347 they are instantiations, not specializations.
349 This function is guaranteed to return 0 if passed NULL_TREE so
350 that, for example, `template_class_depth (current_class_type)' is
351 always safe. */
353 int
355 {
362 {
368 }
371 }
373 /* Subroutine of maybe_begin_member_template_processing.
374 Returns true if processing DECL needs us to push template parms. */
376 static bool
378 {
384 }
386 /* Subroutine of maybe_begin_member_template_processing.
387 Push the template parms in PARMS, starting from LEVELS steps into the
388 chain, and ending at the beginning, since template parms are listed
389 innermost first. */
391 static void
393 {
401 current_template_parms
407 NULL);
409 {
418 {
425 {
426 /* Make a CONST_DECL as is done in process_template_parm.
427 It is ugly that we recreate this here; the original
428 version built in process_template_parm is no longer
429 available. */
439 }
444 }
445 }
446 }
448 /* Restore the template parameter context for a member template or
449 a friend template defined in a class definition. */
451 void
453 {
454 tree parms;
458 {
463 {
466 }
469 }
471 /* Remember how many levels of template parameters we pushed so that
472 we can pop them later. */
474 }
476 /* Undo the effects of maybe_begin_member_template_processing. */
478 void
480 {
489 {
493 }
494 }
496 /* Return a new template argument vector which contains all of ARGS,
497 but has as its innermost set of arguments the EXTRA_ARGS. */
499 static tree
501 {
502 tree new_args;
520 }
522 /* Like add_to_template_args, but only the outermost ARGS are added to
523 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
524 (EXTRA_ARGS) levels are added. This function is used to combine
525 the template arguments from a partial instantiation with the
526 template arguments used to attain the full instantiation from the
527 partial instantiation. */
529 static tree
531 {
532 tree new_args;
534 /* If there are more levels of EXTRA_ARGS than there are ARGS,
535 something very fishy is going on. */
538 /* If *all* the new arguments will be the EXTRA_ARGS, just return
539 them. */
543 /* For the moment, we make ARGS look like it contains fewer levels. */
548 /* Now, we restore ARGS to its full dimensions. */
552 }
554 /* Return the N levels of innermost template arguments from the ARGS. */
556 tree
558 {
559 tree new_args;
565 /* If N is 1, just return the innermost set of template arguments. */
569 /* If we're not removing anything, just return the arguments we were
570 given. */
576 /* Make a new set of arguments, not containing the outer arguments. */
583 }
585 /* The inverse of get_innermost_template_args: Return all but the innermost
586 EXTRA_LEVELS levels of template arguments from the ARGS. */
588 static tree
590 {
591 tree new_args;
597 /* If N is 1, just return the outermost set of template arguments. */
601 /* If we're not removing anything, just return the arguments we were
602 given. */
607 /* Make a new set of arguments, not containing the inner arguments. */
614 }
616 /* We've got a template header coming up; push to a new level for storing
617 the parms. */
619 void
621 {
622 /* We use a non-tag-transparent scope here, which causes pushtag to
623 put tags in this scope, rather than in the enclosing class or
624 namespace scope. This is the right thing, since we want
625 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
626 global template class, push_template_decl handles putting the
627 TEMPLATE_DECL into top-level scope. For a nested template class,
628 e.g.:
630 template <class T> struct S1 {
631 template <class T> struct S2 {};
632 };
634 pushtag contains special code to call pushdecl_with_scope on the
635 TEMPLATE_DECL for S2. */
640 }
642 /* This routine is called when a specialization is declared. If it is
643 invalid to declare a specialization here, an error is reported and
644 false is returned, otherwise this routine will return true. */
646 static bool
648 {
651 /* [temp.expl.spec]
653 An explicit specialization shall be declared in the namespace of
654 which the template is a member, or, for member templates, in the
655 namespace of which the enclosing class or enclosing class
656 template is a member. An explicit specialization of a member
657 function, member class or static data member of a class template
658 shall be declared in the namespace of which the class template
659 is a member. */
661 {
664 }
666 /* [temp.expl.spec]
668 In an explicit specialization declaration for a member of a class
669 template or a member template that appears in namespace scope,
670 the member template and some of its enclosing class templates may
671 remain unspecialized, except that the declaration shall not
672 explicitly specialize a class member template if its enclosing
673 class templates are not explicitly specialized as well. */
675 {
678 }
681 }
683 /* We've just seen template <>. */
685 bool
687 {
691 }
693 /* Called at then end of processing a declaration preceded by
694 template<>. */
696 void
698 {
701 }
703 /* Any template <>'s that we have seen thus far are not referring to a
704 function specialization. */
706 void
708 {
711 }
713 /* We've just seen a template header. If SPECIALIZATION is nonzero,
714 it was of the form template <>. */
716 static void
718 {
720 template_header_count++;
721 }
723 /* We're beginning an explicit instantiation. */
725 void
727 {
730 }
733 void
735 {
738 }
740 /* An explicit specialization or partial specialization of TMPL is being
741 declared. Check that the namespace in which the specialization is
742 occurring is permissible. Returns false iff it is invalid to
743 specialize TMPL in the current namespace. */
745 static bool
747 {
750 /* [tmpl.expl.spec]
752 An explicit specialization shall be declared in the namespace of
753 which the template is a member, or, for member templates, in the
754 namespace of which the enclosing class or enclosing class
755 template is a member. An explicit specialization of a member
756 function, member class or static data member of a class template
757 shall be declared in the namespace of which the class template is
758 a member. */
761 {
764 }
766 /* Same or super-using namespace. */
768 else
769 {
773 }
774 }
776 /* SPEC is an explicit instantiation. Check that it is valid to
777 perform this explicit instantiation in the current namespace. */
779 static void
781 {
782 tree ns;
784 /* DR 275: An explicit instantiation shall appear in an enclosing
785 namespace of its template. */
791 }
793 /* The TYPE is being declared. If it is a template type, that means it
794 is a partial specialization. Do appropriate error-checking. */
796 tree
798 {
799 tree context;
804 /* A lambda that appears in specialization context is not itself a
805 specialization. */
810 {
814 }
819 {
824 else
827 }
829 {
830 /* This is for ordinary explicit specialization and partial
831 specialization of a template class such as:
833 template <> class C<int>;
835 or:
837 template <class T> class C<T*>;
839 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
843 {
848 {
852 }
853 }
859 /* Trying to define a specialization either without a template<> header
860 or in an inappropriate place. We've already given an error, so just
861 bail now so we don't actually define the specialization. */
863 }
869 {
870 /* This is for an explicit specialization of member class
871 template according to [temp.expl.spec/18]:
873 template <> template <class U> class C<int>::D;
875 The context `C<int>' must be an implicit instantiation.
876 Otherwise this is just a member class template declared
877 earlier like:
879 template <> class C<int> { template <class U> class D; };
880 template <> template <class U> class C<int>::D;
882 In the first case, `C<int>::D' is a specialization of `C<T>::D'
883 while in the second case, `C<int>::D' is a primary template
884 and `C<T>::D' may not exist. */
888 {
889 tree t;
894 {
897 }
899 /* Check for invalid specialization after instantiation:
901 template <> template <> class C<int>::D<int>;
902 template <> template <class U> class C<int>::D; */
906 {
909 {
910 /* We already have a full specialization of this partial
911 instantiation. Reassign it to the new member
912 specialization template. */
913 spec_entry elt;
930 }
932 /* But if we've had an implicit instantiation, that's a
933 problem ([temp.expl.spec]/6). */
936 }
938 /* Mark TYPE as a specialization. And as a result, we only
939 have one level of template argument for the innermost
940 class template. */
945 }
946 }
948 {
949 /* Someday C++0x may allow for enum template specialization. */
954 else
955 {
958 }
959 }
962 }
964 /* Returns nonzero if we can optimize the retrieval of specializations
965 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
966 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
970 {
973 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
974 parameter. */
976 /* The optimized lookup depends on the fact that the
977 template arguments for the member function template apply
978 purely to the containing class, which is not true if the
979 containing class is an explicit or partial
980 specialization. */
984 /* It is possible to have a template that is not a member
985 template and is not a member of a template class:
987 template <typename T>
988 struct S { friend A::f(); };
990 Here, the friend function is a template, but the context does
991 not have template information. The optimized lookup relies
992 on having ARGS be the template arguments for both the class
993 and the function template. */
995 }
997 /* Retrieve the specialization (in the sense of [temp.spec] - a
998 specialization is either an instantiation or an explicit
999 specialization) of TMPL for the given template ARGS. If there is
1000 no such specialization, return NULL_TREE. The ARGS are a vector of
1001 arguments, or a vector of vectors of arguments, in the case of
1002 templates with more than one level of parameters.
1004 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1005 then we search for a partial specialization matching ARGS. This
1006 parameter is ignored if TMPL is not a class template. */
1008 static tree
1010 {
1019 /* There should be as many levels of arguments as there are
1020 levels of parameters. */
1025 {
1026 tree class_template;
1027 tree class_specialization;
1029 tree fns;
1032 /* The template arguments actually apply to the containing
1033 class. Find the class specialization with those
1034 arguments. */
1036 class_specialization
1040 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1041 for the specialization. */
1045 /* Iterate through the methods with the indicated name, looking
1046 for the one that has an instance of TMPL. */
1049 {
1052 /* using-declarations can add base methods to the method vec,
1053 and we don't want those here. */
1056 }
1058 }
1059 else
1060 {
1062 spec_entry elt;
1063 htab_t specializations;
1071 else
1079 }
1082 }
1084 /* Like retrieve_specialization, but for local declarations. */
1086 static tree
1088 {
1096 }
1098 /* Returns nonzero iff DECL is a specialization of TMPL. */
1100 int
1102 {
1103 tree t;
1106 {
1112 }
1113 else
1114 {
1123 }
1126 }
1128 /* Returns nonzero iff DECL is a specialization of friend declaration
1129 FRIEND_DECL according to [temp.friend]. */
1131 bool
1133 {
1140 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1141 of a template class, we want to check if DECL is a specialization
1142 if this. */
1146 {
1147 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1150 }
1155 /* There is nothing to do if this is not a template friend. */
1162 /* [temp.friend/6]
1163 A member of a class template may be declared to be a friend of a
1164 non-template class. In this case, the corresponding member of
1165 every specialization of the class template is a friend of the
1166 class granting friendship.
1168 For example, given a template friend declaration
1170 template <class T> friend void A<T>::f();
1172 the member function below is considered a friend
1174 template <> struct A<int> {
1175 void f();
1176 };
1178 For this type of template friend, TEMPLATE_DEPTH below will be
1179 nonzero. To determine if DECL is a friend of FRIEND, we first
1180 check if the enclosing class is a specialization of another. */
1187 {
1188 /* Next, we check the members themselves. In order to handle
1189 a few tricky cases, such as when FRIEND_DECL's are
1191 template <class T> friend void A<T>::g(T t);
1192 template <class T> template <T t> friend void A<T>::h();
1194 and DECL's are
1196 void A<int>::g(int);
1197 template <int> void A<int>::h();
1199 we need to figure out ARGS, the template arguments from
1200 the context of DECL. This is required for template substitution
1201 of `T' in the function parameter of `g' and template parameter
1202 of `h' in the above examples. Here ARGS corresponds to `int'. */
1209 {
1211 {
1214 else
1216 current_depth++;
1217 }
1219 }
1222 {
1224 tree friend_type;
1225 tree decl_type;
1226 tree friend_args_type;
1227 tree decl_args_type;
1229 /* Make sure that both DECL and FRIEND_DECL are templates or
1230 non-templates. */
1236 {
1237 /* If both are templates, check template parameter list. */
1238 tree friend_parms
1243 friend_parms))
1247 }
1248 else
1256 /* Check if return types match. */
1260 /* Check if function parameter types match, ignoring the
1261 `this' parameter. */
1270 }
1271 else
1272 {
1273 /* DECL is a TYPE_DECL */
1277 /* Make sure that both DECL and FRIEND_DECL are templates or
1278 non-templates. */
1279 is_template
1286 {
1287 tree friend_parms;
1288 /* If both are templates, check the name of the two
1289 TEMPLATE_DECL's first because is_friend didn't. */
1294 /* Now check template parameter list. */
1295 friend_parms
1298 return comp_template_parms
1300 friend_parms);
1301 }
1302 else
1305 }
1306 }
1308 }
1310 /* Register the specialization SPEC as a specialization of TMPL with
1311 the indicated ARGS. IS_FRIEND indicates whether the specialization
1312 is actually just a friend declaration. Returns SPEC, or an
1313 equivalent prior declaration, if available. */
1315 static tree
1317 hashval_t hash)
1318 {
1319 tree fn;
1321 spec_entry elt;
1327 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1328 register it; we want the corresponding TEMPLATE_DECL instead.
1329 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1330 the more obvious `uses_template_parms (spec)' to avoid problems
1331 with default function arguments. In particular, given
1332 something like this:
1334 template <class T> void f(T t1, T t = T())
1336 the default argument expression is not substituted for in an
1337 instantiation unless and until it is actually needed. */
1341 /* We don't put these specializations in the hash table, but we might
1342 want to give an error about a mismatch. */
1344 else
1345 {
1353 slot =
1357 else
1359 }
1361 /* We can sometimes try to re-register a specialization that we've
1362 already got. In particular, regenerate_decl_from_template calls
1363 duplicate_decls which will update the specialization list. But,
1364 we'll still get called again here anyhow. It's more convenient
1365 to simply allow this than to try to prevent it. */
1369 {
1371 {
1374 {
1376 fn);
1378 }
1379 else
1380 {
1381 tree clone;
1382 /* This situation should occur only if the first
1383 specialization is an implicit instantiation, the
1384 second is an explicit specialization, and the
1385 implicit instantiation has not yet been used. That
1386 situation can occur if we have implicitly
1387 instantiated a member function and then specialized
1388 it later.
1390 We can also wind up here if a friend declaration that
1391 looked like an instantiation turns out to be a
1392 specialization:
1394 template <class T> void foo(T);
1395 class S { friend void foo<>(int) };
1396 template <> void foo(int);
1398 We transform the existing DECL in place so that any
1399 pointers to it become pointers to the updated
1400 declaration.
1402 If there was a definition for the template, but not
1403 for the specialization, we want this to look as if
1404 there were no definition, and vice versa. */
1407 /* The call to duplicate_decls will have applied
1408 [temp.expl.spec]:
1410 An explicit specialization of a function template
1411 is inline only if it is explicitly declared to be,
1412 and independently of whether its function template
1413 is.
1415 to the primary function; now copy the inline bits to
1416 the various clones. */
1418 {
1423 }
1427 }
1428 }
1430 {
1432 /* Dup decl failed, but this is a new definition. Set the
1433 line number so any errors match this new
1434 definition. */
1438 }
1439 }
1443 /* A specialization must be declared in the same namespace as the
1444 template it is specializing. */
1450 {
1458 /* TMPL is a forward declaration of a template function; keep a list
1459 of all specializations in case we need to reassign them to a friend
1460 template later in tsubst_friend_function. */
1463 }
1466 }
1468 /* Returns true iff two spec_entry nodes are equivalent. Only compares the
1469 TMPL and ARGS members, ignores SPEC. */
1473 static int
1475 {
1486 }
1488 /* Returns a hash for a template TMPL and template arguments ARGS. */
1490 static hashval_t
1492 {
1495 }
1497 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1498 ignoring SPEC. */
1500 static hashval_t
1502 {
1505 }
1507 /* Recursively calculate a hash value for a template argument ARG, for use
1508 in the hash tables of template specializations. */
1510 hashval_t
1512 {
1524 /* We can get one of these when re-hashing a previous entry in the middle
1525 of substituting into a pack expansion. Just look through it. */
1534 {
1542 {
1547 }
1569 {
1572 {
1575 }
1577 }
1581 {
1584 }
1595 val = iterative_hash_template_arg
1607 val);
1609 val);
1618 /* A lambda can't appear in a template arg, but don't crash on
1619 erroneous input. */
1631 /* Now hash operands as usual. */
1636 }
1639 {
1643 val);
1646 /* Otherwise just compare the types during lookup. */
1655 {
1660 }
1661 }
1664 }
1666 /* Unregister the specialization SPEC as a specialization of TMPL.
1667 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1668 if the SPEC was listed as a specialization of TMPL.
1670 Note that SPEC has been ggc_freed, so we can't look inside it. */
1672 bool
1674 {
1676 spec_entry elt;
1684 {
1689 }
1692 }
1694 /* Like register_specialization, but for local declarations. We are
1695 registering SPEC, an instantiation of TMPL. */
1697 static void
1699 {
1704 }
1706 /* TYPE is a class type. Returns true if TYPE is an explicitly
1707 specialized class. */
1709 bool
1711 {
1715 }
1717 /* Print the list of functions at FNS, going through all the overloads
1718 for each element of the list. Alternatively, FNS can not be a
1719 TREE_LIST, in which case it will be printed together with all the
1720 overloads.
1722 MORE and *STR should respectively be FALSE and NULL when the function
1723 is called from the outside. They are used internally on recursive
1724 calls. print_candidates manages the two parameters and leaves NULL
1725 in *STR when it ends. */
1727 static void
1729 {
1735 {
1739 }
1740 else
1741 {
1744 {
1745 /* Pick the prefix string. */
1747 {
1751 }
1755 }
1758 }
1761 {
1764 }
1765 }
1767 /* Print the list of candidate FNS in an error message. FNS can also
1768 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1770 void
1772 {
1776 }
1778 /* Returns the template (one of the functions given by TEMPLATE_ID)
1779 which can be specialized to match the indicated DECL with the
1780 explicit template args given in TEMPLATE_ID. The DECL may be
1781 NULL_TREE if none is available. In that case, the functions in
1782 TEMPLATE_ID are non-members.
1784 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1785 specialization of a member template.
1787 The TEMPLATE_COUNT is the number of references to qualifying
1788 template classes that appeared in the name of the function. See
1789 check_explicit_specialization for a more accurate description.
1791 TSK indicates what kind of template declaration (if any) is being
1792 declared. TSK_TEMPLATE indicates that the declaration given by
1793 DECL, though a FUNCTION_DECL, has template parameters, and is
1794 therefore a template function.
1796 The template args (those explicitly specified and those deduced)
1797 are output in a newly created vector *TARGS_OUT.
1799 If it is impossible to determine the result, an error message is
1800 issued. The error_mark_node is returned to indicate failure. */
1802 static tree
1804 tree decl,
1808 tmpl_spec_kind tsk)
1809 {
1810 tree fns;
1811 tree targs;
1812 tree explicit_targs;
1814 /* A TREE_LIST of templates of which DECL may be a specialization.
1815 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1816 corresponding TREE_PURPOSE is the set of template arguments that,
1817 when used to instantiate the template, would produce a function
1818 with the signature of DECL. */
1828 /* We shouldn't be specializing a member template of an
1829 unspecialized class template; we already gave an error in
1830 check_specialization_scope, now avoid crashing. */
1833 {
1836 }
1844 /* Check for baselinks. */
1849 {
1852 }
1854 /* Count the number of template headers specified for this
1855 specialization. */
1863 {
1867 {
1868 tree decl_arg_types;
1869 tree fn_arg_types;
1870 tree insttype;
1872 /* In case of explicit specialization, we need to check if
1873 the number of template headers appearing in the specialization
1874 is correct. This is usually done in check_explicit_specialization,
1875 but the check done there cannot be exhaustive when specializing
1876 member functions. Consider the following code:
1878 template <> void A<int>::f(int);
1879 template <> template <> void A<int>::f(int);
1881 Assuming that A<int> is not itself an explicit specialization
1882 already, the first line specializes "f" which is a non-template
1883 member function, whilst the second line specializes "f" which
1884 is a template member function. So both lines are syntactically
1885 correct, and check_explicit_specialization does not reject
1886 them.
1888 Here, we can do better, as we are matching the specialization
1889 against the declarations. We count the number of template
1890 headers, and we check if they match TEMPLATE_COUNT + 1
1891 (TEMPLATE_COUNT is the number of qualifying template classes,
1892 plus there must be another header for the member template
1893 itself).
1895 Notice that if header_count is zero, this is not a
1896 specialization but rather a template instantiation, so there
1897 is no check we can perform here. */
1901 /* Check that the number of template arguments at the
1902 innermost level for DECL is the same as for FN. */
1910 /* DECL might be a specialization of FN. */
1914 /* For a non-static member function, we need to make sure
1915 that the const qualification is the same. Since
1916 get_bindings does not try to merge the "this" parameter,
1917 we must do the comparison explicitly. */
1923 /* Skip the "this" parameter and, for constructors of
1924 classes with virtual bases, the VTT parameter. A
1925 full specialization of a constructor will have a VTT
1926 parameter, but a template never will. */
1927 decl_arg_types
1929 fn_arg_types
1932 /* Function templates cannot be specializations; there are
1933 no partial specializations of functions. Therefore, if
1934 the type of DECL does not match FN, there is no
1935 match. */
1937 {
1941 }
1943 /* See whether this function might be a specialization of this
1944 template. Suppress access control because we might be trying
1945 to make this specialization a friend, and we have already done
1946 access control for the declaration of the specialization. */
1952 /* We cannot deduce template arguments that when used to
1953 specialize TMPL will produce DECL. */
1956 /* Make sure that the deduced arguments actually work. */
1960 fn_arg_types
1965 /* Save this template, and the arguments deduced. */
1967 }
1969 /* FN is an ordinary member function, and we need a
1970 specialization of a member template. */
1971 ;
1973 /* We can get IDENTIFIER_NODEs here in certain erroneous
1974 cases. */
1975 ;
1977 /* This is just an ordinary non-member function. Nothing can
1978 be a specialization of that. */
1979 ;
1981 /* Cannot specialize functions that are created implicitly. */
1982 ;
1983 else
1984 {
1985 tree decl_arg_types;
1987 /* This is an ordinary member function. However, since
1988 we're here, we can assume it's enclosing class is a
1989 template class. For example,
1991 template <typename T> struct S { void f(); };
1992 template <> void S<int>::f() {}
1994 Here, S<int>::f is a non-template, but S<int> is a
1995 template class. If FN has the same type as DECL, we
1996 might be in business. */
1999 /* Its enclosing class is an explicit specialization
2000 of a template class. This is not a candidate. */
2005 /* The return types differ. */
2008 /* Adjust the type of DECL in case FN is a static member. */
2015 decl_arg_types))
2016 /* They match! */
2018 }
2019 }
2022 {
2023 /* We have:
2025 [temp.expl.spec]
2027 It is possible for a specialization with a given function
2028 signature to be instantiated from more than one function
2029 template. In such cases, explicit specification of the
2030 template arguments must be used to uniquely identify the
2031 function template specialization being specialized.
2033 Note that here, there's no suggestion that we're supposed to
2034 determine which of the candidate templates is most
2035 specialized. However, we, also have:
2037 [temp.func.order]
2039 Partial ordering of overloaded function template
2040 declarations is used in the following contexts to select
2041 the function template to which a function template
2042 specialization refers:
2044 -- when an explicit specialization refers to a function
2045 template.
2047 So, we do use the partial ordering rules, at least for now.
2048 This extension can only serve to make invalid programs valid,
2049 so it's safe. And, there is strong anecdotal evidence that
2050 the committee intended the partial ordering rules to apply;
2051 the EDG front end has that behavior, and John Spicer claims
2052 that the committee simply forgot to delete the wording in
2053 [temp.expl.spec]. */
2056 {
2059 }
2060 }
2063 {
2071 }
2075 {
2081 }
2083 /* We have one, and exactly one, match. */
2085 {
2088 /* DECL is a re-declaration or partial instantiation of a template
2089 function. */
2092 /* It was a specialization of an ordinary member function in a
2093 template class. */
2095 }
2097 /* It was a specialization of a template. */
2100 {
2105 }
2106 else
2109 }
2111 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2112 but with the default argument values filled in from those in the
2113 TMPL_TYPES. */
2115 static tree
2117 tree tmpl_types)
2118 {
2119 tree new_spec_types;
2127 /* Substitute into the rest of the list. */
2128 new_spec_types =
2132 /* Add the default argument for this parameter. */
2135 new_spec_types);
2136 }
2138 /* DECL is an explicit specialization. Replicate default arguments
2139 from the template it specializes. (That way, code like:
2141 template <class T> void f(T = 3);
2142 template <> void f(double);
2143 void g () { f (); }
2145 works, as required.) An alternative approach would be to look up
2146 the correct default arguments at the call-site, but this approach
2147 is consistent with how implicit instantiations are handled. */
2149 static void
2151 {
2152 tree tmpl;
2153 tree spec_types;
2154 tree tmpl_types;
2155 tree new_spec_types;
2156 tree old_type;
2157 tree new_type;
2158 tree t;
2163 /* See if there's anything we need to do. */
2176 {
2177 /* Remove the this pointer, but remember the object's type for
2178 CV quals. */
2184 {
2185 /* DECL may contain more parameters than TMPL due to the extra
2186 in-charge parameter in constructors and destructors. */
2189 }
2191 {
2194 }
2195 }
2197 /* Compute the merged default arguments. */
2198 new_spec_types =
2201 /* Compute the new FUNCTION_TYPE. */
2203 {
2207 new_spec_types);
2210 /* Put the in-charge parameter back. */
2213 new_spec_types);
2217 new_spec_types);
2218 }
2219 else
2221 new_spec_types);
2227 }
2229 /* Return the number of template headers we expect to see for a definition
2230 or specialization of CTYPE or one of its non-template members. */
2232 int
2234 {
2238 {
2239 /* You're supposed to have one `template <...>' for every
2240 template class, but you don't need one for a full
2241 specialization. For example:
2243 template <class T> struct S{};
2244 template <> struct S<int> { void f(); };
2245 void S<int>::f () {}
2247 is correct; there shouldn't be a `template <>' for the
2248 definition of `S<int>::f'. */
2250 /* If CTYPE does not have template information of any
2251 kind, then it is not a template, nor is it nested
2252 within a template. */
2260 }
2263 }
2265 /* Do a simple sanity check on the template headers that precede the
2266 variable declaration DECL. */
2268 void
2270 {
2277 {
2283 "members of an explicitly specialized class are defined "
2285 }
2286 }
2288 /* Check to see if the function just declared, as indicated in
2289 DECLARATOR, and in DECL, is a specialization of a function
2290 template. We may also discover that the declaration is an explicit
2291 instantiation at this point.
2293 Returns DECL, or an equivalent declaration that should be used
2294 instead if all goes well. Issues an error message if something is
2295 amiss. Returns error_mark_node if the error is not easily
2296 recoverable.
2298 FLAGS is a bitmask consisting of the following flags:
2300 2: The function has a definition.
2301 4: The function is a friend.
2303 The TEMPLATE_COUNT is the number of references to qualifying
2304 template classes that appeared in the name of the function. For
2305 example, in
2307 template <class T> struct S { void f(); };
2308 void S<int>::f();
2310 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2311 classes are not counted in the TEMPLATE_COUNT, so that in
2313 template <class T> struct S {};
2314 template <> struct S<int> { void f(); }
2315 template <> void S<int>::f();
2317 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2318 invalid; there should be no template <>.)
2320 If the function is a specialization, it is marked as such via
2321 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2322 is set up correctly, and it is added to the list of specializations
2323 for that template. */
2325 tree
2327 tree decl,
2330 {
2338 tmpl_spec_kind tsk;
2341 {
2344 else
2346 }
2347 else
2351 {
2354 {
2357 }
2359 {
2361 /* This could be something like:
2363 template <class T> void f(T);
2364 class S { friend void f<>(int); } */
2366 else
2367 {
2368 /* This case handles bogus declarations like template <>
2369 template <class T> void f<int>(); */
2372 declarator);
2374 }
2375 }
2379 /* The error has already been reported in
2380 check_specialization_scope. */
2386 /* Fall through. */
2399 decl);
2402 else
2406 /* Fall through. */
2411 else
2417 {
2418 /* This case handles bogus declarations like template <>
2419 template <class T> void f<int>(); */
2424 else
2426 declarator);
2428 }
2431 /* This is a specialization of a member template, without
2432 specialization the containing class. Something like:
2434 template <class T> struct S {
2435 template <class U> void f (U);
2436 };
2437 template <> template <class U> void S<int>::f(U) {}
2439 That's a specialization -- but of the entire template. */
2445 }
2448 {
2452 {
2456 }
2457 }
2460 {
2464 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2466 {
2467 tree fns;
2472 else
2473 {
2474 /* If there is no class context, the explicit instantiation
2475 must be at namespace scope. */
2478 /* Find the namespace binding, using the declaration
2479 context. */
2483 {
2486 }
2487 else
2488 {
2494 }
2495 }
2498 }
2504 {
2506 /* A specialization in class scope. This is invalid,
2507 but the error will already have been flagged by
2508 check_specialization_scope. */
2510 else
2511 {
2512 /* It's not valid to write an explicit instantiation in
2513 class scope, e.g.:
2515 class C { template void f(); }
2517 This case is caught by the parser. However, on
2518 something like:
2520 template class C { void f(); };
2522 (which is invalid) we can get here. The error will be
2523 issued later. */
2524 ;
2525 }
2528 }
2531 {
2532 /* Find the list of functions in ctype that have the same
2533 name as the declared function. */
2539 {
2544 {
2545 /* From [temp.expl.spec]:
2547 If such an explicit specialization for the member
2548 of a class template names an implicitly-declared
2549 special member function (clause _special_), the
2550 program is ill-formed.
2552 Similar language is found in [temp.explicit]. */
2555 }
2558 }
2561 {
2565 }
2566 else
2567 {
2569 tree ovl;
2571 /* For a type-conversion operator, we cannot do a
2572 name-based lookup. We might be looking for `operator
2573 int' which will be a specialization of `operator T'.
2574 So, we find *all* the conversion operators, and then
2575 select from them. */
2583 {
2585 /* There are no more conversion functions. */
2588 /* Glue all these conversion functions together
2589 with those we already have. */
2592 }
2593 }
2596 {
2599 }
2600 else
2602 }
2604 /* Figure out what exactly is being specialized at this point.
2605 Note that for an explicit instantiation, even one for a
2606 member function, we cannot tell apriori whether the
2607 instantiation is for a member template, or just a member
2608 function of a template class. Even if a member template is
2609 being instantiated, the member template arguments may be
2610 elided if they can be deduced from the rest of the
2611 declaration. */
2614 member_specialization,
2615 template_count,
2616 tsk);
2619 /* We couldn't figure out what this declaration was
2620 specializing. */
2622 else
2623 {
2627 {
2628 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2629 is done by do_decl_instantiation later. */
2635 {
2636 /* If TMPL is not the most general template (for
2637 example, if TMPL is a friend template that is
2638 injected into namespace scope), then there will
2639 be too many levels of TARGS. Remove some of them
2640 here. */
2642 tree new_targs;
2649 }
2652 }
2654 /* If we thought that the DECL was a member function, but it
2655 turns out to be specializing a static member function,
2656 make DECL a static member function as well. */
2661 /* If this is a specialization of a member template of a
2662 template class, we want to return the TEMPLATE_DECL, not
2663 the specialization of it. */
2665 {
2670 {
2671 tree parm;
2675 /* We want to use the argument list specified in the
2676 definition, not in the original declaration. */
2681 }
2684 }
2686 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2689 /* Inherit default function arguments from the template
2690 DECL is specializing. */
2693 /* This specialization has the same protection as the
2694 template it specializes. */
2698 /* 7.1.1-1 [dcl.stc]
2700 A storage-class-specifier shall not be specified in an
2701 explicit specialization...
2703 The parser rejects these, so unless action is taken here,
2704 explicit function specializations will always appear with
2705 global linkage.
2707 The action recommended by the C++ CWG in response to C++
2708 defect report 605 is to make the storage class and linkage
2709 of the explicit specialization match the templated function:
2711 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2712 */
2714 {
2718 /* This specialization has the same linkage and visibility as
2719 the function template it specializes. */
2722 {
2725 }
2728 {
2731 }
2732 }
2734 /* If DECL is a friend declaration, declared using an
2735 unqualified name, the namespace associated with DECL may
2736 have been set incorrectly. For example, in:
2738 template <typename T> void f(T);
2739 namespace N {
2740 struct S { friend void f<int>(int); }
2741 }
2743 we will have set the DECL_CONTEXT for the friend
2744 declaration to N, rather than to the global namespace. */
2749 /* This is not really a declaration of a specialization.
2750 It's just the name of an instantiation. But, it's not
2751 a request for an instantiation, either. */
2754 /* This is indeed a specialization. In case of constructors
2755 and destructors, we need in-charge and not-in-charge
2756 versions in V3 ABI. */
2759 /* Register this specialization so that we can find it
2760 again. */
2762 }
2763 }
2766 }
2768 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2769 parameters. These are represented in the same format used for
2770 DECL_TEMPLATE_PARMS. */
2772 int
2774 {
2775 const_tree p1;
2776 const_tree p2;
2784 {
2796 {
2800 /* If either of the template parameters are invalid, assume
2801 they match for the sake of error recovery. */
2814 }
2815 }
2818 /* One set of parameters has more parameters lists than the
2819 other. */
2823 }
2825 /* Determine whether PARM is a parameter pack. */
2827 bool
2829 {
2830 /* Determine if we have a non-type template parameter pack. */
2837 /* If this is a list of template parameters, we could get a
2838 TYPE_DECL or a TEMPLATE_DECL. */
2842 /* Otherwise it must be a type template parameter. */
2846 }
2848 /* Determine if T is a function parameter pack. */
2850 bool
2852 {
2856 }
2858 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
2859 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
2861 tree
2863 {
2870 }
2872 /* Return true iff the function parameter PARAM_DECL was expanded
2873 from the function parameter pack PACK. */
2875 bool
2877 {
2882 /* The parameter pack and its pack arguments have the same
2883 DECL_PARM_INDEX. */
2885 }
2887 /* Determine whether ARGS describes a variadic template args list,
2888 i.e., one that is terminated by a template argument pack. */
2890 static bool
2892 {
2894 tree last_parm;
2908 }
2910 /* Generate a new name for the parameter pack name NAME (an
2911 IDENTIFIER_NODE) that incorporates its */
2913 static tree
2915 {
2916 /* Munge the name to include the parameter index. */
2917 #define NUMBUF_LEN 128
2931 }
2933 /* Return true if T is a primary function, class or alias template
2934 instantiation. */
2936 bool
2938 {
2952 }
2954 /* Return true if PARM is a template template parameter. */
2956 bool
2958 {
2960 }
2962 /* Return true iff PARM is a DECL representing a type template
2963 parameter. */
2965 bool
2967 {
2972 }
2974 /* Return the template parameters of T if T is a
2975 primary template instantiation, NULL otherwise. */
2977 tree
2979 {
2984 parms = INNERMOST_TEMPLATE_PARMS
2988 }
2990 /* Return the template parameters of the LEVELth level from the full list
2991 of template parameters PARMS. */
2993 tree
2995 {
2996 tree p;
3007 }
3009 /* Returns the template arguments of T if T is a template instantiation,
3010 NULL otherwise. */
3012 tree
3014 {
3022 }
3024 /* Return the argument pack elements of T if T is a template argument pack,
3025 NULL otherwise. */
3027 tree
3029 {
3035 }
3037 /* Structure used to track the progress of find_parameter_packs_r. */
3038 struct find_parameter_pack_data
3039 {
3040 /* TREE_LIST that will contain all of the parameter packs found by
3041 the traversal. */
3044 /* Set of AST nodes that have been visited by the traversal. */
3046 };
3048 /* Identifies all of the argument packs that occur in a template
3049 argument and appends them to the TREE_LIST inside DATA, which is a
3050 find_parameter_pack_data structure. This is a subroutine of
3051 make_pack_expansion and uses_parameter_packs. */
3052 static tree
3054 {
3060 /* Handle type aliases/typedefs. */
3065 {
3072 }
3074 /* Identify whether this is a parameter pack or not. */
3076 {
3091 {
3092 /* We don't want to walk into the type of a PARM_DECL,
3093 because we don't want to see the type parameter pack. */
3096 }
3103 /* Not a parameter pack. */
3105 }
3108 {
3109 /* Add this parameter pack to the list. */
3111 }
3117 /* This switch statement will return immediately if we don't find a
3118 parameter pack. */
3120 {
3125 /* Check the template itself. */
3128 /* Check the template arguments. */
3144 /* Fall through. */
3186 }
3189 }
3191 /* Determines if the expression or type T uses any parameter packs. */
3192 bool
3194 {
3202 }
3204 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3205 representation a base-class initializer into a parameter pack
3206 expansion. If all goes well, the resulting node will be an
3207 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3208 respectively. */
3209 tree
3211 {
3212 tree result;
3221 {
3222 /* The only time we will see a TREE_LIST here is for a base
3223 class initializer. In this case, the TREE_PURPOSE will be a
3224 _TYPE node (representing the base class expansion we're
3225 initializing) and the TREE_VALUE will be a TREE_LIST
3226 containing the initialization arguments.
3228 The resulting expansion looks somewhat different from most
3229 expansions. Rather than returning just one _EXPANSION, we
3230 return a TREE_LIST whose TREE_PURPOSE is a
3231 TYPE_PACK_EXPANSION containing the bases that will be
3232 initialized. The TREE_VALUE will be identical to the
3233 original TREE_VALUE, which is a list of arguments that will
3234 be passed to each base. We do not introduce any new pack
3235 expansion nodes into the TREE_VALUE (although it is possible
3236 that some already exist), because the TREE_PURPOSE and
3237 TREE_VALUE all need to be expanded together with the same
3238 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3239 resulting TREE_PURPOSE will mention the parameter packs in
3240 both the bases and the arguments to the bases. */
3241 tree purpose;
3242 tree value;
3245 /* Determine which parameter packs will be used by the base
3246 class expansion. */
3253 {
3257 }
3260 {
3261 /* Collect the sets of parameter packs used in each of the
3262 initialization arguments. */
3264 {
3265 /* Determine which parameter packs will be expanded in this
3266 argument. */
3269 }
3270 }
3274 /* Create the pack expansion type for the base type. */
3279 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3280 they will rarely be compared to anything. */
3284 }
3289 /* Build the PACK_EXPANSION_* node. */
3290 result = for_types
3295 {
3296 /* Propagate type and const-expression information. */
3299 }
3300 else
3301 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3302 they will rarely be compared to anything. */
3305 /* Determine which parameter packs will be expanded. */
3311 /* Make sure we found some parameter packs. */
3313 {
3316 else
3319 }
3325 }
3327 /* Checks T for any "bare" parameter packs, which have not yet been
3328 expanded, and issues an error if any are found. This operation can
3329 only be done on full expressions or types (e.g., an expression
3330 statement, "if" condition, etc.), because we could have expressions like:
3332 foo(f(g(h(args)))...)
3334 where "args" is a parameter pack. check_for_bare_parameter_packs
3335 should not be called for the subexpressions args, h(args),
3336 g(h(args)), or f(g(h(args))), because we would produce erroneous
3337 error messages.
3339 Returns TRUE and emits an error if there were bare parameter packs,
3340 returns FALSE otherwise. */
3341 bool
3343 {
3359 {
3362 {
3371 else
3376 else
3380 }
3383 }
3386 }
3388 /* Expand any parameter packs that occur in the template arguments in
3389 ARGS. */
3390 tree
3392 {
3398 /* First, determine if we need to expand anything, and the number of
3399 slots we'll need. */
3401 {
3406 {
3410 else
3412 }
3413 else
3414 {
3416 num_result_args++;
3417 }
3418 }
3420 /* If no expansion is necessary, we're done. */
3424 /* Expand arguments. */
3427 non_default_args_count =
3430 {
3433 {
3440 }
3441 else
3442 {
3445 }
3446 }
3450 }
3452 /* Checks if DECL shadows a template parameter.
3454 [temp.local]: A template-parameter shall not be redeclared within its
3455 scope (including nested scopes).
3457 Emits an error and returns TRUE if the DECL shadows a parameter,
3458 returns FALSE otherwise. */
3460 bool
3462 {
3463 tree olddecl;
3465 /* If we're not in a template, we can't possibly shadow a template
3466 parameter. */
3470 /* Figure out what we're shadowing. */
3475 /* If there's no previous binding for this name, we're not shadowing
3476 anything, let alone a template parameter. */
3480 /* If we're not shadowing a template parameter, we're done. Note
3481 that OLDDECL might be an OVERLOAD (or perhaps even an
3482 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3483 node. */
3487 /* We check for decl != olddecl to avoid bogus errors for using a
3488 name inside a class. We check TPFI to avoid duplicate errors for
3489 inline member templates. */
3497 }
3499 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3500 ORIG_LEVEL, DECL, and TYPE. */
3502 static tree
3506 tree decl,
3507 tree type)
3508 {
3519 }
3521 /* Find the canonical type parameter for the given template type
3522 parameter. Returns the canonical type parameter, which may be TYPE
3523 if no such parameter existed. */
3525 static tree
3527 {
3528 tree list;
3542 else
3543 {
3548 }
3549 }
3551 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3552 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3553 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3554 new one is created. */
3556 static tree
3558 tsubst_flags_t complain)
3559 {
3564 {
3583 /* Template template parameters need this. */
3588 }
3591 }
3593 /* Process information from new template parameter PARM and append it
3594 to the LIST being built. This new parameter is a non-type
3595 parameter iff IS_NON_TYPE is true. This new parameter is a
3596 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3597 is in PARM_LOC. NUM_TEMPLATE_PARMS is the size of the template
3598 parameter list PARM belongs to. This is used used to create a
3599 proper canonical type for the type of PARM that is to be created,
3600 iff PARM is a type. If the size is not known, this parameter shall
3601 be set to 0. */
3603 tree
3606 {
3608 tree defval;
3609 tree err_parm_list;
3616 {
3620 {
3624 else
3626 }
3629 }
3630 else
3634 {
3640 {
3644 }
3645 else
3646 {
3647 /* [temp.param]
3649 The top-level cv-qualifiers on the template-parameter are
3650 ignored when determining its type. */
3653 {
3657 }
3660 {
3661 /* This template parameter is not a parameter pack, but it
3662 should be. Complain about "bare" parameter packs. */
3665 /* Recover by calling this a parameter pack. */
3667 }
3668 }
3670 /* A template parameter is not modifiable. */
3679 processing_template_decl,
3684 }
3685 else
3686 {
3687 tree t;
3691 {
3693 /* This is for distinguishing between real templates and template
3694 template parameters */
3698 }
3699 else
3700 {
3702 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3705 }
3712 processing_template_decl,
3716 }
3722 }
3724 /* The end of a template parameter list has been reached. Process the
3725 tree list into a parameter vector, converting each parameter into a more
3726 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3727 as PARM_DECLs. */
3729 tree
3731 {
3736 current_template_parms
3741 {
3745 }
3750 }
3752 /* end_template_decl is called after a template declaration is seen. */
3754 void
3756 {
3762 /* This matches the pushlevel in begin_template_parm_list. */
3767 }
3769 /* Takes a TREE_LIST representing a template parameter and convert it
3770 into an argument suitable to be passed to the type substitution
3771 functions. Note that If the TREE_LIST contains an error_mark
3772 node, the returned argument is error_mark_node. */
3774 static tree
3776 {
3789 {
3793 {
3794 /* Turn this argument into a TYPE_ARGUMENT_PACK
3795 with a single element, which expands T. */
3797 #ifdef ENABLE_CHECKING
3798 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3800 #endif
3805 }
3806 }
3807 else
3808 {
3812 {
3813 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3814 with a single element, which expands T. */
3817 #ifdef ENABLE_CHECKING
3818 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3820 #endif
3826 }
3827 }
3829 }
3831 /* Given a set of template parameters, return them as a set of template
3832 arguments. The template parameters are represented as a TREE_VEC, in
3833 the form documented in cp-tree.h for template arguments. */
3835 static tree
3837 {
3838 tree header;
3843 /* If there is only one level of template parameters, we do not
3844 create a TREE_VEC of TREE_VECs. Instead, we return a single
3845 TREE_VEC containing the arguments. */
3850 {
3858 #ifdef ENABLE_CHECKING
3860 #endif
3864 else
3866 }
3869 /* This can happen for template parms of a template template
3870 parameter, e.g:
3872 template<template<class T, class U> class TT> struct S;
3874 Consider the level of the parms of TT; T and U both have
3875 level 2; TT has no template parm of level 1. So in this case
3876 the first element of full_template_args is NULL_TREE. If we
3877 leave it like this TMPL_ARG_DEPTH on args returns 1 instead
3878 of 2. This will make tsubst wrongly consider that T and U
3879 have level 1. Instead, let's create a dummy vector as the
3880 first element of full_template_args so that TMPL_ARG_DEPTH
3881 returns the correct depth for args. */
3884 }
3886 /* Within the declaration of a template, return the currently active
3887 template parameters as an argument TREE_VEC. */
3889 static tree
3891 {
3893 }
3895 /* Update the declared TYPE by doing any lookups which were thought to be
3896 dependent, but are not now that we know the SCOPE of the declarator. */
3898 tree
3900 {
3911 /* Don't bother building up the args in this case. */
3913 {
3914 /* tsubst in the args corresponding to the template parameters,
3915 including auto if present. Most things will be unchanged, but
3916 make_typename_type and tsubst_qualified_id will resolve
3917 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
3920 tree pushed;
3922 {
3926 }
3931 }
3937 {
3940 else
3942 }
3944 }
3946 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
3947 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
3948 a member template. Used by push_template_decl below. */
3950 static tree
3952 {
3960 }
3962 struct template_parm_data
3963 {
3964 /* The level of the template parameters we are currently
3965 processing. */
3968 /* The index of the specialization argument we are currently
3969 processing. */
3972 /* An array whose size is the number of template parameters. The
3973 elements are nonzero if the parameter has been used in any one
3974 of the arguments processed so far. */
3977 /* An array whose size is the number of template arguments. The
3978 elements are nonzero if the argument makes use of template
3979 parameters of this level. */
3981 };
3983 /* Subroutine of push_template_decl used to see if each template
3984 parameter in a partial specialization is used in the explicit
3985 argument list. If T is of the LEVEL given in DATA (which is
3986 treated as a template_parm_data*), then DATA->PARMS is marked
3987 appropriately. */
3989 static int
3991 {
3997 {
4000 }
4001 else
4002 {
4005 }
4008 {
4011 }
4013 /* Return zero so that for_each_template_parm will continue the
4014 traversal of the tree; we want to mark *every* template parm. */
4016 }
4018 /* Process the partial specialization DECL. */
4020 static tree
4022 {
4028 tree inner_parms;
4029 tree inst;
4042 /* We check that each of the template parameters given in the
4043 partial specialization is used in the argument list to the
4044 specialization. For example:
4046 template <class T> struct S;
4047 template <class T> struct S<T*>;
4049 The second declaration is OK because `T*' uses the template
4050 parameter T, whereas
4052 template <class T> struct S<int>;
4054 is no good. Even trickier is:
4056 template <class T>
4057 struct S1
4058 {
4059 template <class U>
4060 struct S2;
4061 template <class U>
4062 struct S2<T>;
4063 };
4065 The S2<T> declaration is actually invalid; it is a
4066 full-specialization. Of course,
4068 template <class U>
4069 struct S2<T (*)(U)>;
4071 or some such would have been OK. */
4079 {
4084 NULL,
4086 }
4089 {
4090 /* One of the template parms was not used in the
4091 specialization. */
4093 {
4096 }
4099 }
4104 /* [temp.class.spec]
4106 The argument list of the specialization shall not be identical to
4107 the implicit argument list of the primary template. */
4114 /* A partial specialization that replaces multiple parameters of the
4115 primary template with a pack expansion is less specialized for those
4116 parameters. */
4118 {
4120 "primary template because it replaces multiple parameters "
4124 }
4126 /* [temp.class.spec]
4128 A partially specialized non-type argument expression shall not
4129 involve template parameters of the partial specialization except
4130 when the argument expression is a simple identifier.
4132 The type of a template parameter corresponding to a specialized
4133 non-type argument shall not be dependent on a parameter of the
4134 specialization.
4136 Also, we verify that pack expansions only occur at the
4137 end of the argument list. */
4141 {
4148 {
4149 /* Extract the arguments from the argument pack. We'll be
4150 iterating over these in the following loop. */
4153 }
4156 {
4158 /* Get the Jth argument in the parameter pack. */
4162 {
4163 /* Pack expansions must come at the end of the
4164 argument list. */
4167 {
4171 else
4174 }
4175 }
4178 /* We only care about the pattern. */
4184 /* This next line is the `argument expression is not just a
4185 simple identifier' condition and also the `specialized
4186 non-type argument' bit. */
4188 {
4192 arg);
4193 else
4194 {
4195 /* Look at the corresponding template parameter,
4196 marking which template parameters its type depends
4197 upon. */
4201 {
4202 /* We haven't yet initialized TPD2. Do so now. */
4204 /* The number of parameters here is the number in the
4205 main template, which, as checked in the assertion
4206 above, is NARGS. */
4210 }
4212 /* Mark the template parameters. But this time, we're
4213 looking for the template parameters of the main
4214 template, not in the specialization. */
4221 NULL,
4225 {
4226 /* The type depended on some template parameters.
4227 If they are fully specialized in the
4228 specialization, that's OK. */
4237 "type %qT of template argument %qE depends "
4239 "type %qT of template argument %qE depends "
4241 type,
4242 arg);
4243 }
4244 }
4245 }
4246 }
4247 }
4249 /* We should only get here once. */
4259 {
4263 {
4267 "partial specialization of %qT after instantiation "
4269 }
4270 }
4273 }
4275 /* Check that a template declaration's use of default arguments and
4276 parameter packs is not invalid. Here, PARMS are the template
4277 parameters. IS_PRIMARY is true if DECL is the thing declared by
4278 a primary template. IS_PARTIAL is true if DECL is a partial
4279 specialization.
4281 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4282 declaration (but not a definition); 1 indicates a declaration, 2
4283 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4284 emitted for extraneous default arguments.
4286 Returns TRUE if there were no errors found, FALSE otherwise. */
4288 bool
4291 {
4294 tree parm_level;
4297 /* [temp.param]
4299 A default template-argument shall not be specified in a
4300 function template declaration or a function template definition, nor
4301 in the template-parameter-list of the definition of a member of a
4302 class template. */
4305 /* You can't have a function template declaration in a local
4306 scope, nor you can you define a member of a class template in a
4307 local scope. */
4313 /* A lambda doesn't have an explicit declaration; don't complain
4314 about the parms of the enclosing class. */
4321 /* If this is either a friend defined in the scope of the class
4322 or a member function. */
4328 /* And, if it was a member function, it really was defined in
4329 the scope of the class. */
4332 /* We already checked these parameters when the template was
4333 declared, so there's no need to do it again now. This function
4334 was defined in class scope, but we're processing it's body now
4335 that the class is complete. */
4338 /* Core issue 226 (C++0x only): the following only applies to class
4339 templates. */
4342 {
4343 /* [temp.param]
4345 If a template-parameter has a default template-argument, all
4346 subsequent template-parameters shall have a default
4347 template-argument supplied. */
4349 {
4356 {
4366 {
4368 /* For better subsequent error-recovery, we indicate that
4369 there should have been a default argument. */
4372 }
4374 && !is_friend_decl
4375 /* Don't complain about an enclosing partial
4376 specialization. */
4381 {
4382 /* A primary class template can only have one
4383 parameter pack, at the end of the template
4384 parameter list. */
4389 else
4397 }
4398 }
4399 }
4400 }
4403 || is_partial
4404 || !is_primary
4406 /* For an ordinary class template, default template arguments are
4407 allowed at the innermost level, e.g.:
4408 template <class T = int>
4409 struct S {};
4410 but, in a partial specialization, they're not allowed even
4411 there, as we have in [temp.class.spec]:
4413 The template parameter list of a specialization shall not
4414 contain default template argument values.
4416 So, for a partial specialization, or for a function template
4417 (in C++98/C++03), we look at all of them. */
4418 ;
4419 else
4420 /* But, for a primary class template that is not a partial
4421 specialization we look at all template parameters except the
4422 innermost ones. */
4425 /* Figure out what error message to issue. */
4438 else
4442 /* If we're inside a class definition, there's no need to
4443 examine the parameters to the class itself. On the one
4444 hand, they will be checked when the class is defined, and,
4445 on the other, default arguments are valid in things like:
4446 template <class T = double>
4447 struct S { template <class U> void f(U); };
4448 Here the default argument for `S' has no bearing on the
4449 declaration of `f'. */
4451 else
4452 /* Check everything. */
4458 {
4465 {
4470 {
4472 {
4479 }
4481 /* Clear out the default argument so that we are not
4482 confused later. */
4484 }
4485 }
4487 /* At this point, if we're still interested in issuing messages,
4488 they must apply to classes surrounding the object declared. */
4492 }
4495 }
4497 /* Worker for push_template_decl_real, called via
4498 for_each_template_parm. DATA is really an int, indicating the
4499 level of the parameters we are interested in. If T is a template
4500 parameter of that level, return nonzero. */
4502 static int
4504 {
4510 else
4513 }
4515 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
4516 parameters given by current_template_args, or reuses a
4517 previously existing one, if appropriate. Returns the DECL, or an
4518 equivalent one, if it is replaced via a call to duplicate_decls.
4520 If IS_FRIEND is true, DECL is a friend declaration. */
4522 tree
4524 {
4525 tree tmpl;
4526 tree args;
4527 tree info;
4528 tree ctx;
4532 /* True if the template is a member template, in the sense of
4533 [temp.mem]. */
4539 /* See if this is a partial specialization. */
4548 /* For a friend, we want the context of the friend function, not
4549 the type of which it is a friend. */
4553 /* In the case of a virtual function, we want the class in which
4554 it is defined. */
4556 else
4557 /* Otherwise, if we're currently defining some class, the DECL
4558 is assumed to be a member of the class. */
4567 /* See if this is a primary template. */
4569 /* A friend template that specifies a class context, i.e.
4570 template <typename T> friend void A<T>::f();
4571 is not primary. */
4573 else
4577 {
4582 {
4585 }
4587 {
4589 {
4590 /* [temp.mem]
4592 A destructor shall not be a member template. */
4595 }
4602 {
4603 /* [basic.stc.dynamic.allocation]
4605 An allocation function can be a function
4606 template. ... Template allocation functions shall
4607 have two or more parameters. */
4610 }
4611 }
4617 /* alias-declaration */
4619 else
4620 {
4623 }
4624 }
4626 /* Check to see that the rules regarding the use of default
4627 arguments are not being violated. */
4631 /* Ensure that there are no parameter packs in the type of this
4632 declaration that have not been expanded. */
4634 {
4635 /* Check each of the arguments individually to see if there are
4636 any bare parameter packs. */
4642 {
4645 {
4646 /* This is a PARM_DECL that contains unexpanded parameter
4647 packs. We have already complained about this in the
4648 check_for_bare_parameter_packs call, so just replace
4649 these types with ERROR_MARK_NODE. */
4652 }
4656 }
4658 /* Check for bare parameter packs in the return type and the
4659 exception specifiers. */
4661 /* Errors were already issued, set return type to int
4662 as the frontend doesn't expect error_mark_node as
4663 the return type. */
4667 }
4672 {
4675 }
4688 {
4693 /* If DECL is a TYPE_DECL for a class-template, then there won't
4694 be DECL_LANG_SPECIFIC. The information equivalent to
4695 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
4699 {
4700 /* Since a template declaration already existed for this
4701 class-type, we must be redeclaring it here. Make sure
4702 that the redeclaration is valid. */
4704 current_template_parms);
4705 /* We don't need to create a new TEMPLATE_DECL; just use the
4706 one we already had. */
4708 }
4709 else
4710 {
4712 member_template_p);
4717 {
4718 /* A specialization of a member template of a template
4719 class. */
4723 }
4724 }
4725 }
4726 else
4727 {
4733 {
4736 }
4744 {
4745 tree new_tmpl;
4747 /* The declaration is a specialization of a member
4748 template, declared outside the class. Therefore, the
4749 innermost template arguments will be NULL, so we
4750 replace them with the arguments determined by the
4751 earlier call to check_explicit_specialization. */
4754 new_tmpl
4756 member_template_p);
4766 args,
4769 }
4771 /* Make sure the template headers we got make sense. */
4776 {
4779 }
4780 else
4782 {
4787 {
4791 else
4795 /* Avoid crash in import_export_decl. */
4798 }
4803 /* Can happen in erroneous input. */
4805 else
4809 }
4811 /* Check that the parms are used in the appropriate qualifying scopes
4812 in the declarator. */
4816 {
4822 /* Avoid crash in import_export_decl. */
4825 }
4826 }
4831 /* Push template declarations for global functions and types. Note
4832 that we do not try to push a global template friend declared in a
4833 template class; such a thing may well depend on the template
4834 parameters of the class. */
4837 {
4842 /* Hide template friend classes that haven't been declared yet. */
4844 {
4847 }
4848 }
4851 {
4857 {
4860 /* It is a conversion operator. See if the type converted to
4861 depends on innermost template operands. */
4864 depth))
4866 }
4868 /* Give template template parms a DECL_CONTEXT of the template
4869 for which they are a parameter. */
4872 {
4876 }
4877 }
4879 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
4880 back to its most general template. If TMPL is a specialization,
4881 ARGS may only have the innermost set of arguments. Add the missing
4882 argument levels if necessary. */
4890 else
4891 {
4896 }
4899 }
4901 tree
4903 {
4905 }
4907 /* FN is an inheriting constructor that inherits from the constructor
4908 template INHERITED; turn FN into a constructor template with a matching
4909 template header. */
4911 tree
4913 {
4914 tree inner_parms
4917 tree parms
4928 }
4930 /* Called when a class template TYPE is redeclared with the indicated
4931 template PARMS, e.g.:
4933 template <class T> struct S;
4934 template <class T> struct S {}; */
4936 bool
4938 {
4939 tree tmpl;
4940 tree tmpl_parms;
4944 {
4947 }
4951 /* The type is nested in some template class. Nothing to worry
4952 about here; there are no new template parameters for the nested
4953 type. */
4957 {
4959 tmpl);
4961 }
4967 {
4977 }
4980 {
4981 tree tmpl_parm;
4982 tree parm;
4983 tree tmpl_default;
4984 tree parm_default;
4998 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
4999 TEMPLATE_DECL. */
5009 {
5013 }
5016 {
5017 /* We have in [temp.param]:
5019 A template-parameter may not be given default arguments
5020 by two different declarations in the same scope. */
5025 }
5028 /* Update the previous template parameters (which are the ones
5029 that will really count) with the new default value. */
5032 /* Update the new parameters, too; they'll be used as the
5033 parameters for any members. */
5035 }
5038 }
5040 /* Simplify EXPR if it is a non-dependent expression. Returns the
5041 (possibly simplified) expression. */
5043 tree
5045 {
5049 /* If we're in a template, but EXPR isn't value dependent, simplify
5050 it. We're supposed to treat:
5052 template <typename T> void f(T[1 + 1]);
5053 template <typename T> void f(T[2]);
5055 as two declarations of the same function, for example. */
5059 {
5060 HOST_WIDE_INT saved_processing_template_decl;
5066 complain,
5071 }
5073 }
5075 tree
5077 {
5079 }
5081 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5082 template declaration, or a TYPE_DECL for an alias declaration. */
5084 bool
5086 {
5094 }
5096 /* Return TRUE iff is a specialization of an alias template. */
5098 bool
5100 {
5108 }
5110 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5111 must be a function or a pointer-to-function type, as specified
5112 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5113 and check that the resulting function has external linkage. */
5115 static tree
5117 {
5120 linkage_kind linkage;
5132 /* [temp.arg.nontype]/1
5134 A template-argument for a non-type, non-template template-parameter
5135 shall be one of:
5136 [...]
5137 -- the address of an object or function with external [C++11: or
5138 internal] linkage. */
5141 {
5145 else
5148 }
5152 {
5157 else
5162 }
5165 }
5167 /* Subroutine of convert_nontype_argument.
5168 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5169 Emit an error otherwise. */
5171 static bool
5173 tsubst_flags_t complain)
5174 {
5181 {
5185 }
5187 }
5189 /* Returns TRUE iff the address of OP is value-dependent.
5191 14.6.2.4 [temp.dep.temp]:
5192 A non-integral non-type template-argument is dependent if its type is
5193 dependent or it has either of the following forms
5194 qualified-id
5195 & qualified-id
5196 and contains a nested-name-specifier which specifies a class-name that
5197 names a dependent type.
5199 We generalize this to just say that the address of a member of a
5200 dependent class is value-dependent; the above doesn't cover the
5201 address of a static data member named with an unqualified-id. */
5203 static bool
5205 {
5206 /* We could use get_inner_reference here, but there's no need;
5207 this is only relevant for template non-type arguments, which
5208 can only be expressed as &id-expression. */
5210 {
5214 }
5217 }
5219 /* The next set of functions are used for providing helpful explanatory
5220 diagnostics for failed overload resolution. Their messages should be
5221 indented by two spaces for consistency with the messages in
5222 call.c */
5224 static int
5226 {
5228 }
5230 static int
5232 {
5237 }
5239 static int
5241 {
5243 }
5245 static int
5247 {
5253 }
5255 static int
5257 {
5261 }
5263 static int
5265 {
5268 " template parameter %qD is not a parameter pack, but "
5272 }
5274 static int
5276 {
5279 " template argument %qE does not match "
5283 }
5285 static int
5287 {
5291 }
5293 static int
5295 {
5301 }
5303 static int
5305 {
5307 {
5312 else
5314 " deduced conflicting values for non-type parameter "
5316 }
5318 }
5320 static int
5322 {
5325 " variable-sized array type %qT is not "
5327 arg);
5329 }
5331 static int
5333 {
5337 arg);
5339 }
5341 static int
5343 {
5350 }
5352 static int
5354 {
5356 }
5358 static int
5360 {
5362 }
5364 static int
5367 {
5372 }
5374 static int
5377 {
5380 {
5388 }
5390 }
5392 static int
5394 {
5397 " template parameters of a template template argument are "
5400 }
5402 static int
5404 {
5410 }
5412 static int
5414 {
5419 }
5421 static int
5423 {
5427 arg);
5429 }
5431 /* Attempt to convert the non-type template parameter EXPR to the
5432 indicated TYPE. If the conversion is successful, return the
5433 converted value. If the conversion is unsuccessful, return
5434 NULL_TREE if we issued an error message, or error_mark_node if we
5435 did not. We issue error messages for out-and-out bad template
5436 parameters, but not simply because the conversion failed, since we
5437 might be just trying to do argument deduction. Both TYPE and EXPR
5438 must be non-dependent.
5440 The conversion follows the special rules described in
5441 [temp.arg.nontype], and it is much more strict than an implicit
5442 conversion.
5444 This function is called twice for each template argument (see
5445 lookup_template_class for a more accurate description of this
5446 problem). This means that we need to handle expressions which
5447 are not valid in a C++ source, but can be created from the
5448 first call (for instance, casts to perform conversions). These
5449 hacks can go away after we fix the double coercion problem. */
5451 static tree
5453 {
5454 tree expr_type;
5456 /* Detect immediately string literals as invalid non-type argument.
5457 This special-case is not needed for correctness (we would easily
5458 catch this later), but only to provide better diagnostic for this
5459 common user mistake. As suggested by DR 100, we do not mention
5460 linkage issues in the diagnostic as this is not the point. */
5461 /* FIXME we're making this OK. */
5463 {
5469 }
5471 /* Add the ADDR_EXPR now for the benefit of
5472 value_dependent_expression_p. */
5475 {
5479 }
5481 /* If we are in a template, EXPR may be non-dependent, but still
5482 have a syntactic, rather than semantic, form. For example, EXPR
5483 might be a SCOPE_REF, rather than the VAR_DECL to which the
5484 SCOPE_REF refers. Preserving the qualifying scope is necessary
5485 so that access checking can be performed when the template is
5486 instantiated -- but here we need the resolved form so that we can
5487 convert the argument. */
5498 else
5501 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
5502 to a non-type argument of "nullptr". */
5506 /* In C++11, integral or enumeration non-type template arguments can be
5507 arbitrary constant expressions. Pointer and pointer to
5508 member arguments can be general constant expressions that evaluate
5509 to a null value, but otherwise still need to be of a specific form. */
5511 {
5513 /* A PTRMEM_CST is already constant, and a valid template
5514 argument for a parameter of pointer to member type, we just want
5515 to leave it in that form rather than lower it to a
5520 {
5525 }
5526 }
5528 /* HACK: Due to double coercion, we can get a
5529 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5530 which is the tree that we built on the first call (see
5531 below when coercing to reference to object or to reference to
5532 function). We just strip everything and get to the arg.
5533 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5534 for examples. */
5536 {
5542 {
5543 /* ??? Maybe we could use convert_from_reference here, but we
5544 would need to relax its constraints because the NOP_EXPR
5545 could actually change the type to something more cv-qualified,
5546 and this is not folded by convert_from_reference. */
5551 && (same_type_ignoring_top_level_qualifiers_p
5554 {
5557 }
5558 }
5559 }
5561 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5562 parameter is a pointer to object, through decay and
5563 qualification conversion. Let's strip everything. */
5565 {
5570 {
5571 /* Skip the ADDR_EXPR only if it is part of the decay for
5572 an array. Otherwise, it is part of the original argument
5573 in the source code. */
5578 }
5579 }
5581 /* [temp.arg.nontype]/5, bullet 1
5583 For a non-type template-parameter of integral or enumeration type,
5584 integral promotions (_conv.prom_) and integral conversions
5585 (_conv.integral_) are applied. */
5587 {
5596 /* Notice that there are constant expressions like '4 % 0' which
5597 do not fold into integer constants. */
5599 {
5601 {
5612 /* else cxx_constant_value complained but gave us
5613 a real constant, so go ahead. */
5615 }
5616 else
5618 }
5619 }
5620 /* [temp.arg.nontype]/5, bullet 2
5622 For a non-type template-parameter of type pointer to object,
5623 qualification conversions (_conv.qual_) and the array-to-pointer
5624 conversion (_conv.array_) are applied. */
5626 {
5627 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
5629 A template-argument for a non-type, non-template template-parameter
5630 shall be one of: [...]
5632 -- the name of a non-type template-parameter;
5633 -- the address of an object or function with external linkage, [...]
5634 expressed as "& id-expression" where the & is optional if the name
5635 refers to a function or array, or if the corresponding
5636 template-parameter is a reference.
5638 Here, we do not care about functions, as they are invalid anyway
5639 for a parameter of type pointer-to-object. */
5642 /* Non-type template parameters are OK. */
5643 ;
5648 {
5650 {
5652 "because %qD is a variable, not the address of "
5656 }
5658 {
5663 }
5664 /* Other values, like integer constants, might be valid
5665 non-type arguments of some other type. */
5667 }
5668 else
5669 {
5670 tree decl;
5675 {
5680 }
5682 {
5687 }
5689 {
5694 }
5695 }
5704 }
5705 /* [temp.arg.nontype]/5, bullet 3
5707 For a non-type template-parameter of type reference to object, no
5708 conversions apply. The type referred to by the reference may be more
5709 cv-qualified than the (otherwise identical) type of the
5710 template-argument. The template-parameter is bound directly to the
5711 template-argument, which must be an lvalue. */
5713 {
5715 expr_type))
5719 {
5723 }
5726 {
5730 }
5732 /* [temp.arg.nontype]/1
5734 A template-argument for a non-type, non-template template-parameter
5735 shall be one of: [...]
5737 -- the address of an object or function with external linkage. */
5740 {
5743 {
5745 "because a reference variable does not have a constant "
5748 }
5749 }
5752 {
5757 }
5760 {
5765 }
5768 }
5769 /* [temp.arg.nontype]/5, bullet 4
5771 For a non-type template-parameter of type pointer to function, only
5772 the function-to-pointer conversion (_conv.func_) is applied. If the
5773 template-argument represents a set of overloaded functions (or a
5774 pointer to such), the matching function is selected from the set
5775 (_over.over_). */
5777 {
5778 /* If the argument is a template-id, we might not have enough
5779 context information to decay the pointer. */
5781 {
5785 }
5788 /* Null pointer values are OK in C++11. */
5794 }
5795 /* [temp.arg.nontype]/5, bullet 5
5797 For a non-type template-parameter of type reference to function, no
5798 conversions apply. If the template-argument represents a set of
5799 overloaded functions, the matching function is selected from the set
5800 (_over.over_). */
5802 {
5804 {
5809 }
5816 }
5817 /* [temp.arg.nontype]/5, bullet 6
5819 For a non-type template-parameter of type pointer to member function,
5820 no conversions apply. If the template-argument represents a set of
5821 overloaded member functions, the matching member function is selected
5822 from the set (_over.over_). */
5824 {
5829 /* [temp.arg.nontype] bullet 1 says the pointer to member
5830 expression must be a pointer-to-member constant. */
5834 /* There is no way to disable standard conversions in
5835 resolve_address_of_overloaded_function (called by
5836 instantiate_type). It is possible that the call succeeded by
5837 converting &B::I to &D::I (where B is a base of D), so we need
5838 to reject this conversion here.
5840 Actually, even if there was a way to disable standard conversions,
5841 it would still be better to reject them here so that we can
5842 provide a superior diagnostic. */
5844 {
5848 /* If we are just one standard conversion off, explain. */
5853 }
5854 }
5855 /* [temp.arg.nontype]/5, bullet 7
5857 For a non-type template-parameter of type pointer to data member,
5858 qualification conversions (_conv.qual_) are applied. */
5860 {
5861 /* [temp.arg.nontype] bullet 1 says the pointer to member
5862 expression must be a pointer-to-member constant. */
5869 }
5871 {
5873 {
5877 }
5879 }
5880 /* A template non-type parameter must be one of the above. */
5881 else
5884 /* Sanity check: did we actually convert the argument to the
5885 right type? */
5889 }
5891 /* Subroutine of coerce_template_template_parms, which returns 1 if
5892 PARM_PARM and ARG_PARM match using the rule for the template
5893 parameters of template template parameters. Both PARM and ARG are
5894 template parameters; the rest of the arguments are the same as for
5895 coerce_template_template_parms.
5896 */
5897 static int
5899 tree arg,
5900 tsubst_flags_t complain,
5901 tree in_decl,
5902 tree outer_args)
5903 {
5912 {
5914 /* We encounter instantiations of templates like
5915 template <template <template <class> class> class TT>
5916 class C; */
5917 {
5924 }
5925 /* Fall through. */
5930 /* Argument is a parameter pack but parameter is not. */
5935 /* The tsubst call is used to handle cases such as
5937 template <int> class C {};
5938 template <class T, template <T> class TT> class D {};
5939 D<int, C> d;
5941 i.e. the parameter list of TT depends on earlier parameters. */
5943 && !same_type_p
5950 /* Argument is a parameter pack but parameter is not. */
5957 }
5960 }
5963 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
5964 template template parameters. Both PARM_PARMS and ARG_PARMS are
5965 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
5966 or PARM_DECL.
5968 Consider the example:
5969 template <class T> class A;
5970 template<template <class U> class TT> class B;
5972 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
5973 the parameters to A, and OUTER_ARGS contains A. */
5975 static int
5977 tree arg_parms,
5978 tsubst_flags_t complain,
5979 tree in_decl,
5980 tree outer_args)
5981 {
5992 /* Determine whether we have a parameter pack at the end of the
5993 template template parameter's template parameter list. */
5995 {
6002 {
6016 }
6017 }
6023 /* Check all of the template parameters except the parameter pack at
6024 the end (if any). */
6026 {
6035 outer_args))
6038 }
6041 {
6042 /* Check each of the template parameters in the template
6043 argument against the template parameter pack at the end of
6044 the template template parameter. */
6051 {
6058 outer_args))
6060 }
6061 }
6064 }
6066 /* Verifies that the deduced template arguments (in TARGS) for the
6067 template template parameters (in TPARMS) represent valid bindings,
6068 by comparing the template parameter list of each template argument
6069 to the template parameter list of its corresponding template
6070 template parameter, in accordance with DR150. This
6071 routine can only be called after all template arguments have been
6072 deduced. It will return TRUE if all of the template template
6073 parameter bindings are okay, FALSE otherwise. */
6074 bool
6076 {
6080 /* We're dealing with template parms in this process. */
6086 {
6091 {
6096 {
6097 /* Look inside the argument pack. */
6100 }
6103 {
6107 /* Extract the next argument from the argument
6108 pack. */
6112 /* Look at the pattern of the pack expansion. */
6115 /* Extract the template parameters from the template
6116 argument. */
6122 /* Verify that we can coerce the template template
6123 parameters from the template argument to the template
6124 parameter. This requires an exact match. */
6126 && !coerce_template_template_parms
6128 targ_parms,
6129 tf_none,
6130 tparm,
6131 targs))
6132 {
6135 }
6136 }
6137 }
6138 }
6140 out:
6144 }
6146 /* Since type attributes aren't mangled, we need to strip them from
6147 template type arguments. */
6149 static tree
6151 {
6152 tree mv;
6159 {
6164 }
6166 }
6168 /* Convert the indicated template ARG as necessary to match the
6169 indicated template PARM. Returns the converted ARG, or
6170 error_mark_node if the conversion was unsuccessful. Error and
6171 warning messages are issued under control of COMPLAIN. This
6172 conversion is for the Ith parameter in the parameter list. ARGS is
6173 the full set of template arguments deduced so far. */
6175 static tree
6177 tree arg,
6178 tree args,
6179 tsubst_flags_t complain,
6181 tree in_decl)
6182 {
6183 tree orig_arg;
6184 tree val;
6189 {
6190 /* The template argument was the name of some
6191 member function. That's usually
6192 invalid, but static members are OK. In any
6193 case, grab the underlying fields/functions
6194 and issue an error later if required. */
6197 }
6205 /* When determining whether an argument pack expansion is a template,
6206 look at the pattern. */
6210 /* Deal with an injected-class-name used as a template template arg. */
6212 {
6215 {
6225 }
6226 }
6228 is_tmpl_type =
6244 {
6246 {
6250 }
6253 "to refer to a type member of a template parameter, "
6258 typename_type,
6259 complain);
6262 }
6264 {
6266 {
6268 {
6278 else
6280 }
6281 }
6283 }
6285 {
6287 {
6293 else
6295 }
6297 }
6300 {
6302 {
6306 /* The number of argument required is not known yet.
6307 Just accept it for now. */
6309 else
6310 {
6312 tree argparm;
6318 args))
6319 {
6322 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6323 TEMPLATE_DECL. */
6325 {
6330 }
6331 }
6332 else
6333 {
6335 {
6341 }
6344 }
6345 }
6346 }
6347 else
6349 /* We only form one instance of each template specialization.
6350 Therefore, if we use a non-canonical variant (i.e., a
6351 typedef), any future messages referring to the type will use
6352 the typedef, which is confusing if those future uses do not
6353 themselves also use the typedef. */
6356 }
6357 else
6358 {
6365 {
6368 else
6369 {
6370 /* Not sure if this is reachable, but it doesn't hurt
6371 to be robust. */
6374 }
6375 }
6377 /* We used to call digest_init here. However, digest_init
6378 will report errors, which we don't want when complain
6379 is zero. More importantly, digest_init will try too
6380 hard to convert things: for example, `0' should not be
6381 converted to pointer type at this point according to
6382 the standard. Accepting this is not merely an
6383 extension, since deciding whether or not these
6384 conversions can occur is part of determining which
6385 function template to call, or whether a given explicit
6386 argument specification is valid. */
6388 else
6397 {
6398 /* Strip typedefs from the SCOPE_REF. */
6401 complain);
6404 }
6405 }
6408 }
6410 /* Coerces the remaining template arguments in INNER_ARGS (from
6411 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6412 Returns the coerced argument pack. PARM_IDX is the position of this
6413 parameter in the template parameter list. ARGS is the original
6414 template argument list. */
6415 static tree
6418 tree args,
6419 tree inner_args,
6421 tree new_args,
6423 tree in_decl,
6424 tsubst_flags_t complain)
6425 {
6428 tree packed_args;
6429 tree argument_pack;
6439 {
6440 /* When the template parameter is a non-type template
6441 parameter pack whose type uses parameter packs, we need
6442 to look at each of the template arguments
6443 separately. Build a vector of the types for these
6444 non-type template parameters in PACKED_TYPES. */
6445 tree expansion
6453 /* Check that we have the right number of arguments. */
6457 {
6458 int needed_parms
6463 }
6465 /* If we aren't able to check the actual arguments now
6466 (because they haven't been expanded yet), we can at least
6467 verify that all of the types used for the non-type
6468 template parameter pack are, in fact, valid for non-type
6469 template parameters. */
6472 {
6475 {
6479 }
6480 }
6481 }
6483 /* Convert the remaining arguments, which will be a part of the
6484 parameter pack "parm". */
6486 {
6491 {
6492 /* When we have a vector of types (corresponding to the
6493 non-type template parameter pack that uses parameter
6494 packs in its type, as mention above), and the
6495 argument is not an expansion (which expands to a
6496 currently unknown number of arguments), clone the
6497 parm and give it the next type in PACKED_TYPES. */
6501 }
6504 {
6507 }
6508 else
6511 in_decl);
6515 }
6520 else
6521 {
6526 }
6529 #ifdef ENABLE_CHECKING
6532 #endif
6534 }
6536 /* Returns true if the template argument vector ARGS contains
6537 any pack expansions, false otherwise. */
6539 static bool
6541 {
6548 }
6550 /* Convert all template arguments to their appropriate types, and
6551 return a vector containing the innermost resulting template
6552 arguments. If any error occurs, return error_mark_node. Error and
6553 warning messages are issued under control of COMPLAIN.
6555 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6556 for arguments not specified in ARGS. Otherwise, if
6557 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
6558 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
6559 USE_DEFAULT_ARGS is false, then all arguments must be specified in
6560 ARGS. */
6562 static tree
6564 tree args,
6565 tree in_decl,
6566 tsubst_flags_t complain,
6569 {
6571 tree inner_args;
6572 tree new_args;
6573 tree new_inner_args;
6577 /* When used as a boolean value, indicates whether this is a
6578 variadic template parameter list. Since it's an int, we can also
6579 subtract it from nparms to get the number of non-variadic
6580 parameters. */
6589 /* Determine if there are any parameter packs. */
6591 {
6597 }
6600 /* If there are no parameters that follow a parameter pack, we need to
6601 expand any argument packs so that we can deduce a parameter pack from
6602 some non-packed args followed by an argument pack, as in variadic85.C.
6603 If there are such parameters, we need to leave argument packs intact
6604 so the arguments are assigned properly. This can happen when dealing
6605 with a nested class inside a partial specialization of a class
6606 template, as in variadic92.C, or when deducing a template parameter pack
6607 from a sub-declarator, as in variadic114.C. */
6614 && require_all_args
6616 && (!use_default_args
6619 {
6621 {
6623 {
6627 }
6628 else
6634 }
6637 }
6639 /* We need to evaluate the template arguments, even though this
6640 template-id may be nested within a "sizeof". */
6648 {
6649 tree arg;
6650 tree parm;
6652 /* Get the Ith template parameter. */
6656 {
6659 }
6661 /* Calculate the next argument. */
6664 else
6669 {
6670 /* All remaining arguments will be placed in the
6671 template parameter pack PARM. */
6677 /* Store this argument. */
6679 lost++;
6682 /* We are done with all of the arguments. */
6686 }
6688 {
6690 {
6691 /* We don't know how many args we have yet, just
6692 use the unconverted ones for now. */
6695 }
6696 }
6698 {
6699 /* There must be a default arg in this case. */
6702 /* The position of the first default template argument,
6703 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
6704 Record that. */
6707 }
6708 else
6712 {
6715 }
6717 /* This only occurs if there was an error in the template
6718 parameter list itself (which we would already have
6719 reported) that we are trying to recover from, e.g., a class
6720 template with a parameter list such as
6721 template<typename..., typename>. */
6723 else
6729 lost++;
6731 }
6738 #ifdef ENABLE_CHECKING
6742 #endif
6745 }
6747 /* Like coerce_template_parms. If PARMS represents all template
6748 parameters levels, this function returns a vector of vectors
6749 representing all the resulting argument levels. Note that in this
6750 case, only the innermost arguments are coerced because the
6751 outermost ones are supposed to have been coerced already.
6753 Otherwise, if PARMS represents only (the innermost) vector of
6754 parameters, this function returns a vector containing just the
6755 innermost resulting arguments. */
6757 static tree
6759 tree args,
6760 tree in_decl,
6761 tsubst_flags_t complain,
6764 {
6767 tree coerced_args;
6770 {
6772 tree level;
6778 {
6779 tree l;
6783 require_all_args,
6784 use_default_args);
6785 else
6792 }
6793 }
6794 else
6797 require_all_args,
6798 use_default_args);
6800 }
6802 /* Returns 1 if template args OT and NT are equivalent. */
6804 static int
6806 {
6813 /* For member templates */
6822 {
6839 }
6841 {
6842 /* We get here probably because we are in the middle of substituting
6843 into the pattern of a pack expansion. In that case the
6844 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
6845 interested in. So we want to use the initial pack argument for
6846 the comparison. */
6851 }
6856 else
6858 }
6860 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
6861 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
6862 NEWARG_PTR with the offending arguments if they are non-NULL. */
6864 static int
6867 {
6880 {
6885 {
6891 }
6892 }
6894 }
6896 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
6897 of template arguments. Returns 0 otherwise. */
6899 int
6901 {
6903 }
6905 static void
6907 {
6917 /* We are called both from instantiate_decl, where we've already had a
6918 tinst_level pushed, and instantiate_template, where we haven't.
6919 Compensate. */
6930 else
6939 }
6942 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
6943 ARGLIST. Valid choices for FNS are given in the cp-tree.def
6944 documentation for TEMPLATE_ID_EXPR. */
6946 tree
6948 {
6949 tree type;
6957 {
6960 }
6963 {
6965 unknown_type_node,
6967 arglist);
6969 }
6976 }
6978 /* Within the scope of a template class S<T>, the name S gets bound
6979 (in build_self_reference) to a TYPE_DECL for the class, not a
6980 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
6981 or one of its enclosing classes, and that type is a template,
6982 return the associated TEMPLATE_DECL. Otherwise, the original
6983 DECL is returned.
6985 Also handle the case when DECL is a TREE_LIST of ambiguous
6986 injected-class-names from different bases. */
6988 tree
6990 {
6994 /* DR 176: A lookup that finds an injected-class-name (10.2
6995 [class.member.lookup]) can result in an ambiguity in certain cases
6996 (for example, if it is found in more than one base class). If all of
6997 the injected-class-names that are found refer to specializations of
6998 the same class template, and if the name is followed by a
6999 template-argument-list, the reference refers to the class template
7000 itself and not a specialization thereof, and is not ambiguous. */
7002 {
7005 {
7011 }
7014 else
7016 }
7022 }
7024 /* Given an IDENTIFIER_NODE (type TEMPLATE_DECL) and a chain of
7025 parameters, find the desired type.
7027 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
7029 IN_DECL, if non-NULL, is the template declaration we are trying to
7030 instantiate.
7032 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
7033 the class we are looking up.
7035 Issue error and warning messages under control of COMPLAIN.
7037 If the template class is really a local class in a template
7038 function, then the FUNCTION_CONTEXT is the function in which it is
7039 being instantiated.
7041 ??? Note that this function is currently called *twice* for each
7042 template-id: the first time from the parser, while creating the
7043 incomplete type (finish_template_type), and the second type during the
7044 real instantiation (instantiate_template_class). This is surely something
7045 that we want to avoid. It also causes some problems with argument
7046 coercion (see convert_nontype_argument for more information on this). */
7048 static tree
7051 {
7053 tree t;
7056 spec_entry elt;
7057 hashval_t hash;
7060 {
7064 else
7065 {
7072 }
7075 }
7077 {
7080 /* If we are declaring a constructor, say A<T>::A<T>, we will get
7081 an implicit typename for the second A. Deal with it. */
7086 {
7089 }
7090 }
7093 {
7096 }
7100 {
7104 }
7106 /* Issue an error message if we didn't find a template. */
7108 {
7112 }
7115 /* Make sure it's a user visible template, if it was named by
7116 the user. */
7119 {
7121 {
7125 }
7127 }
7132 {
7133 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7134 template arguments */
7136 tree parm;
7137 tree arglist2;
7138 tree outer;
7142 /* Consider an example where a template template parameter declared as
7144 template <class T, class U = std::allocator<T> > class TT
7146 The template parameter level of T and U are one level larger than
7147 of TT. To proper process the default argument of U, say when an
7148 instantiation `TT<int>' is seen, we need to build the full
7149 arguments containing {int} as the innermost level. Outer levels,
7150 available when not appearing as default template argument, can be
7151 obtained from the arguments of the enclosing template.
7153 Suppose that TT is later substituted with std::vector. The above
7154 instantiation is `TT<int, std::allocator<T> >' with TT at
7155 level 1, and T at level 2, while the template arguments at level 1
7156 becomes {std::vector} and the inner level 2 is {int}. */
7162 /* This is an argument of the current template, so we haven't set
7163 DECL_CONTEXT yet. */
7170 complain,
7180 }
7181 else
7182 {
7184 tree gen_tmpl;
7185 tree type_decl;
7193 /* An error occured while building the template TEMPL, and a
7194 diagnostic has most certainly been emitted for that
7195 already. Let's propagate that error. */
7204 {
7205 /* We've been given an incomplete set of template arguments.
7206 For example, given:
7208 template <class T> struct S1 {
7209 template <class U> struct S2 {};
7210 template <class U> struct S2<U*> {};
7211 };
7213 we will be called with an ARGLIST of `U*', but the
7214 TEMPLATE will be `template <class T> template
7215 <class U> struct S1<T>::S2'. We must fill in the missing
7216 arguments. */
7217 arglist
7219 arglist);
7221 }
7223 /* Now we should have enough arguments. */
7226 /* From here on, we're only interested in the most general
7227 template. */
7229 /* Calculate the BOUND_ARGS. These will be the args that are
7230 actually tsubst'd into the definition to create the
7231 instantiation. */
7233 {
7234 /* We have multiple levels of arguments to coerce, at once. */
7244 {
7245 tree a;
7249 complain,
7252 else
7253 /* Outer levels should have already been coerced. */
7256 /* Don't process further if one of the levels fails. */
7258 {
7259 /* Restore the ARGLIST to its full size. */
7262 }
7266 /* We temporarily reduce the length of the ARGLIST so
7267 that coerce_template_parms will see only the arguments
7268 corresponding to the template parameters it is
7269 examining. */
7271 }
7273 /* Restore the ARGLIST to its full size. */
7277 }
7278 else
7279 arglist
7282 gen_tmpl,
7283 complain,
7288 /* We were unable to bind the arguments. */
7291 /* In the scope of a template class, explicit references to the
7292 template class refer to the type of the template, not any
7293 instantiation of it. For example, in:
7295 template <class T> class C { void f(C<T>); }
7297 the `C<T>' is just the same as `C'. Outside of the
7298 class, however, such a reference is an instantiation. */
7302 /* comp_template_args is expensive, check it last. */
7304 arglist))
7307 /* If we already have this specialization, return it. */
7319 /* If the deduced arguments are invalid, then the binding
7320 failed. */
7324 complain))
7331 {
7336 }
7346 /* Create the type. */
7348 {
7350 {
7356 }
7357 else
7358 {
7359 /* We don't want to call start_enum for this type, since
7360 the values for the enumeration constants may involve
7361 template parameters. And, no one should be interested
7362 in the enumeration constants for such a type. */
7365 }
7369 }
7371 {
7372 /* The user referred to a specialization of an alias
7373 template represented by GEN_TMPL.
7375 [temp.alias]/2 says:
7377 When a template-id refers to the specialization of an
7378 alias template, it is equivalent to the associated
7379 type obtained by substitution of its
7380 template-arguments for the template-parameters in the
7381 type-id of the alias template. */
7384 /* Note that the call above (by indirectly calling
7385 register_specialization in tsubst_decl) registers the
7386 TYPE_DECL representing the specialization of the alias
7387 template. So next time someone substitutes ARGLIST for
7388 the template parms into the alias template (GEN_TMPL),
7389 she'll get that TYPE_DECL back. */
7393 }
7395 {
7402 /* A local class. Make sure the decl gets registered properly. */
7407 /* This instantiation is another name for the primary
7408 template type. Set the TYPE_CANONICAL field
7409 appropriately. */
7412 /* Some of the template arguments require structural
7413 equality testing, so this template class requires
7414 structural equality testing. */
7416 }
7417 else
7420 /* If we called start_enum or pushtag above, this information
7421 will already be set up. */
7423 {
7430 }
7431 else
7435 {
7441 {
7444 }
7445 }
7447 /* Let's consider the explicit specialization of a member
7448 of a class template specialization that is implicitely instantiated,
7449 e.g.:
7450 template<class T>
7451 struct S
7452 {
7453 template<class U> struct M {}; //#0
7454 };
7456 template<>
7457 template<>
7458 struct S<int>::M<char> //#1
7459 {
7460 int i;
7461 };
7462 [temp.expl.spec]/4 says this is valid.
7464 In this case, when we write:
7465 S<int>::M<char> m;
7467 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
7468 the one of #0.
7470 When we encounter #1, we want to store the partial instantiation
7471 of M (template<class T> S<int>::M<T>) in it's CLASSTYPE_TI_TEMPLATE.
7473 For all cases other than this "explicit specialization of member of a
7474 class template", we just want to store the most general template into
7475 the CLASSTYPE_TI_TEMPLATE of M.
7477 This case of "explicit specialization of member of a class template"
7478 only happens when:
7479 1/ the enclosing class is an instantiation of, and therefore not
7480 the same as, the context of the most general template, and
7481 2/ we aren't looking at the partial instantiation itself, i.e.
7482 the innermost arguments are not the same as the innermost parms of
7483 the most general template.
7485 So it's only when 1/ and 2/ happens that we want to use the partial
7486 instantiation of the member template in lieu of its most general
7487 template. */
7491 /* the enclosing class must be an instantiation... */
7494 {
7495 tree partial_inst_args;
7498 partial_inst_args =
7504 use_partial_inst_tmpl =
7505 /*...and we must not be looking at the partial instantiation
7506 itself. */
7508 partial_inst_args);
7509 }
7512 /* This case is easy; there are no member templates involved. */
7514 else
7515 {
7516 /* This is a full instantiation of a member template. Find
7517 the partial instantiation of which this is an instance. */
7519 /* Temporarily reduce by one the number of levels in the ARGLIST
7520 so as to avoid comparing the last set of arguments. */
7524 /* FOUND is either a proper class type, or an alias
7525 template specialization. In the later case, it's a
7526 TYPE_DECL, resulting from the substituting of arguments
7527 for parameters in the TYPE_DECL of the alias template
7528 done earlier. So be careful while getting the template
7529 of FOUND. */
7533 }
7544 /* Note this use of the partial instantiation so we can check it
7545 later in maybe_process_partial_specialization. */
7551 /* Now that the type has been registered on the instantiations
7552 list, we set up the enumerators. Because the enumeration
7553 constants may involve the enumeration type itself, we make
7554 sure to register the type first, and then create the
7555 constants. That way, doing tsubst_expr for the enumeration
7556 constants won't result in recursive calls here; we'll find
7557 the instantiation and exit above. */
7561 /* If the type makes use of template parameters, the
7562 code that generates debugging information will crash. */
7565 /* Possibly limit visibility based on template args. */
7570 }
7571 }
7573 /* Wrapper for lookup_template_class_1. */
7575 tree
7578 {
7579 tree ret;
7585 }
7586 \f
7587 struct pair_fn_data
7588 {
7589 tree_fn_t fn;
7591 /* True when we should also visit template parameters that occur in
7592 non-deduced contexts. */
7595 };
7597 /* Called from for_each_template_parm via walk_tree. */
7599 static tree
7601 {
7614 {
7618 /* Fall through. */
7641 /* Since we're not going to walk subtrees, we have to do this
7642 explicitly here. */
7646 /* Fall through. */
7649 /* Check the return type. */
7654 /* Check the parameter types. Since default arguments are not
7655 instantiated until they are needed, the TYPE_ARG_TYPES may
7656 contain expressions that involve template parameters. But,
7657 no-one should be looking at them yet. And, once they're
7658 instantiated, they don't contain template parameters, so
7659 there's no point in looking at them then, either. */
7660 {
7661 tree parm;
7668 /* Since we've already handled the TYPE_ARG_TYPES, we don't
7669 want walk_tree walking into them itself. */
7671 }
7689 /* Fall through. */
7705 /* Record template parameters such as `T' inside `TT<T>'. */
7709 /* Fall through. */
7721 /* A template template parameter is encountered. */
7727 /* Already substituted template template parameter */
7750 /* If there's no type, then this thing must be some expression
7751 involving template parameters. */
7773 }
7775 /* We didn't find any template parameters we liked. */
7777 }
7779 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
7780 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
7781 call FN with the parameter and the DATA.
7782 If FN returns nonzero, the iteration is terminated, and
7783 for_each_template_parm returns 1. Otherwise, the iteration
7784 continues. If FN never returns a nonzero value, the value
7785 returned by for_each_template_parm is 0. If FN is NULL, it is
7786 considered to be the function which always returns 1.
7788 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
7789 parameters that occur in non-deduced contexts. When false, only
7790 visits those template parameters that can be deduced. */
7792 static int
7796 {
7800 /* Set up. */
7805 /* Walk the tree. (Conceptually, we would like to walk without
7806 duplicates, but for_each_template_parm_r recursively calls
7807 for_each_template_parm, so we would need to reorganize a fair
7808 bit to use walk_tree_without_duplicates, so we keep our own
7809 visited list.) */
7812 else
7815 for_each_template_parm_r,
7819 /* Clean up. */
7821 {
7824 }
7827 }
7829 /* Returns true if T depends on any template parameter. */
7831 int
7833 {
7860 else
7861 {
7864 }
7869 }
7871 /* Returns true iff current_function_decl is an incompletely instantiated
7872 template. Useful instead of processing_template_decl because the latter
7873 is set to 0 during fold_non_dependent_expr. */
7875 bool
7877 {
7886 }
7888 /* Returns true if T depends on any template parameter with level LEVEL. */
7890 int
7892 {
7895 }
7897 /* Returns TRUE iff INST is an instantiation we don't need to do in an
7898 ill-formed translation unit, i.e. a variable or function that isn't
7899 usable in a constant expression. */
7903 {
7907 }
7909 /* Returns TRUE iff we should refuse to instantiate DECL because it's
7910 neglectable and instantiated from within an erroneous instantiation. */
7912 static bool
7914 {
7925 }
7933 /* We're starting to instantiate D; record the template instantiation context
7934 for diagnostics and to restore it later. */
7936 int
7938 {
7942 {
7948 else
7956 }
7958 /* If the current instantiation caused problems, don't let it instantiate
7959 anything else. Do allow deduction substitution and decls usable in
7960 constant expressions. */
7977 }
7979 /* We're done instantiating this template; return to the instantiation
7980 context. */
7982 void
7984 {
7985 /* Restore the filename and line number stashed away when we started
7986 this instantiation. */
7990 }
7992 /* We're instantiating a deferred template; restore the template
7993 instantiation context in which the instantiation was requested, which
7994 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
7996 static tree
7998 {
8010 }
8012 /* Returns the TINST_LEVEL which gives the original instantiation
8013 context. */
8017 {
8023 }
8025 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
8026 vector of template arguments, as for tsubst.
8028 Returns an appropriate tsubst'd friend declaration. */
8030 static tree
8032 {
8033 tree new_friend;
8038 /* This was a friend declared with an explicit template
8039 argument list, e.g.:
8041 friend void f<>(T);
8043 to indicate that f was a template instantiation, not a new
8044 function declaration. Now, we have to figure out what
8045 instantiation of what template. */
8046 {
8048 tree new_args;
8049 tree tmpl;
8052 /* Friend functions are looked up in the containing namespace scope.
8053 We must enter that scope, to avoid finding member functions of the
8054 current class with same name. */
8069 tsk_none);
8071 }
8075 /* The NEW_FRIEND will look like an instantiation, to the
8076 compiler, but is not an instantiation from the point of view of
8077 the language. For example, we might have had:
8079 template <class T> struct S {
8080 template <class U> friend void f(T, U);
8081 };
8083 Then, in S<int>, template <class U> void f(int, U) is not an
8084 instantiation of anything. */
8090 {
8094 }
8096 /* The mangled name for the NEW_FRIEND is incorrect. The function
8097 is not a template instantiation and should not be mangled like
8098 one. Therefore, we forget the mangling here; we'll recompute it
8099 later if we need it. */
8101 {
8104 }
8107 {
8108 tree old_decl;
8109 tree new_friend_template_info;
8110 tree new_friend_result_template_info;
8111 tree ns;
8114 /* We must save some information from NEW_FRIEND before calling
8115 duplicate decls since that function will free NEW_FRIEND if
8116 possible. */
8118 new_friend_is_defn =
8123 {
8124 /* This declaration is a `primary' template. */
8127 new_friend_result_template_info
8129 }
8130 else
8133 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8137 /* Inside pushdecl_namespace_level, we will push into the
8138 current namespace. However, the friend function should go
8139 into the namespace of the template. */
8149 {
8150 /* This new friend declaration matched an existing
8151 declaration. For example, given:
8153 template <class T> void f(T);
8154 template <class U> class C {
8155 template <class T> friend void f(T) {}
8156 };
8158 the friend declaration actually provides the definition
8159 of `f', once C has been instantiated for some type. So,
8160 old_decl will be the out-of-class template declaration,
8161 while new_friend is the in-class definition.
8163 But, if `f' was called before this point, the
8164 instantiation of `f' will have DECL_TI_ARGS corresponding
8165 to `T' but not to `U', references to which might appear
8166 in the definition of `f'. Previously, the most general
8167 template for an instantiation of `f' was the out-of-class
8168 version; now it is the in-class version. Therefore, we
8169 run through all specialization of `f', adding to their
8170 DECL_TI_ARGS appropriately. In particular, they need a
8171 new set of outer arguments, corresponding to the
8172 arguments for this class instantiation.
8174 The same situation can arise with something like this:
8176 friend void f(int);
8177 template <class T> class C {
8178 friend void f(T) {}
8179 };
8181 when `C<int>' is instantiated. Now, `f(int)' is defined
8182 in the class. */
8185 /* On the other hand, if the in-class declaration does
8186 *not* provide a definition, then we don't want to alter
8187 existing definitions. We can just leave everything
8188 alone. */
8189 ;
8190 else
8191 {
8195 /* Overwrite whatever template info was there before, if
8196 any, with the new template information pertaining to
8197 the declaration. */
8201 {
8202 /* We should have called reregister_specialization in
8203 duplicate_decls. */
8208 /* Instantiate it if the global has already been used. */
8212 }
8213 else
8214 {
8215 tree t;
8217 /* Indicate that the old function template is a partial
8218 instantiation. */
8226 /* Reassign any specializations already in the hash table
8227 to the new more general template, and add the
8228 additional template args. */
8232 {
8234 spec_entry elt;
8246 register_specialization
8249 }
8251 }
8252 }
8254 /* The information from NEW_FRIEND has been merged into OLD_DECL
8255 by duplicate_decls. */
8257 }
8258 }
8259 else
8260 {
8264 /* In the code
8265 template <class T> class C {
8266 template <class U> friend void C1<U>::f (); // case 1
8267 friend void C2<T>::f (); // case 2
8268 };
8269 we only need to make sure CONTEXT is a complete type for
8270 case 2. To distinguish between the two cases, we note that
8271 CONTEXT of case 1 remains dependent type after tsubst while
8272 this isn't true for case 2. */
8282 {
8283 /* Check to see that the declaration is really present, and,
8284 possibly obtain an improved declaration. */
8290 }
8291 }
8294 }
8296 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8297 template arguments, as for tsubst.
8299 Returns an appropriate tsubst'd friend type or error_mark_node on
8300 failure. */
8302 static tree
8304 {
8305 tree friend_type;
8306 tree tmpl;
8307 tree context;
8310 {
8313 }
8318 {
8321 else
8323 }
8325 /* Look for a class template declaration. We look for hidden names
8326 because two friend declarations of the same template are the
8327 same. For example, in:
8329 struct A {
8330 template <typename> friend class F;
8331 };
8332 template <typename> struct B {
8333 template <typename> friend class F;
8334 };
8336 both F templates are the same. */
8340 /* But, if we don't find one, it might be because we're in a
8341 situation like this:
8343 template <class T>
8344 struct S {
8345 template <class U>
8346 friend struct S;
8347 };
8349 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8350 for `S<int>', not the TEMPLATE_DECL. */
8352 {
8355 }
8358 {
8359 /* The friend template has already been declared. Just
8360 check to see that the declarations match, and install any new
8361 default parameters. We must tsubst the default parameters,
8362 of course. We only need the innermost template parameters
8363 because that is all that redeclare_class_template will look
8364 at. */
8367 {
8368 tree parms;
8369 location_t saved_input_location;
8378 }
8381 }
8382 else
8383 {
8384 /* The friend template has not already been declared. In this
8385 case, the instantiation of the template class will cause the
8386 injection of this template into the global scope. */
8391 /* The new TMPL is not an instantiation of anything, so we
8392 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
8393 the new type because that is supposed to be the corresponding
8394 template decl, i.e., TMPL. */
8401 /* Inject this template into the global scope. */
8403 }
8406 {
8409 else
8411 }
8414 }
8416 /* Returns zero if TYPE cannot be completed later due to circularity.
8417 Otherwise returns one. */
8419 static int
8421 {
8431 else
8433 }
8435 /* Apply any attributes which had to be deferred until instantiation
8436 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
8437 ARGS, COMPLAIN, IN_DECL are as tsubst. */
8439 static void
8442 {
8444 tree t;
8449 {
8453 }
8456 {
8460 }
8461 else
8465 {
8470 {
8473 {
8476 /* If the first attribute argument is an identifier, don't
8477 pass it through tsubst. Attributes like mode, format,
8478 cleanup and several target specific attributes expect it
8479 unmodified. */
8484 {
8485 tree chain
8487 in_decl,
8492 chain);
8493 }
8494 else
8500 }
8501 else
8503 }
8506 }
8507 }
8509 /* Perform (or defer) access check for typedefs that were referenced
8510 from within the template TMPL code.
8511 This is a subroutine of instantiate_decl and instantiate_class_template.
8512 TMPL is the template to consider and TARGS is the list of arguments of
8513 that template. */
8515 static void
8517 {
8518 location_t saved_location;
8529 {
8541 /* Make access check error messages point to the location
8542 of the use of the typedef. */
8546 tf_warning_or_error);
8547 }
8549 }
8551 static tree
8553 {
8555 tree typedecl;
8556 tree pbinfo;
8557 tree base_list;
8559 tree fn_context;
8568 /* Figure out which template is being instantiated. */
8572 /* Determine what specialization of the original template to
8573 instantiate. */
8576 {
8579 }
8581 {
8582 /* This TYPE is actually an instantiation of a partial
8583 specialization. We replace the innermost set of ARGS with
8584 the arguments appropriate for substitution. For example,
8585 given:
8587 template <class T> struct S {};
8588 template <class T> struct S<T*> {};
8590 and supposing that we are instantiating S<int*>, ARGS will
8591 presently be {int*} -- but we need {int}. */
8594 }
8595 else
8596 {
8599 }
8601 /* If the template we're instantiating is incomplete, then clearly
8602 there's nothing we can do. */
8606 /* If we've recursively instantiated too many templates, stop. */
8610 /* Now we're really doing the instantiation. Mark the type as in
8611 the process of being defined. */
8614 /* We may be in the middle of deferred access check. Disable
8615 it now. */
8621 /* Use #pragma pack from the template context. */
8627 /* Set the input location to the most specialized template definition.
8628 This is needed if tsubsting causes an error. */
8640 {
8643 /* Adjust visibility for template arguments. */
8645 }
8650 /* We should never instantiate a nested class before its enclosing
8651 class; we need to look up the nested class by name before we can
8652 instantiate it, and that lookup should instantiate the enclosing
8653 class. */
8659 {
8660 tree pbase_binfo;
8661 tree pushed_scope;
8664 /* We must enter the scope containing the type, as that is where
8665 the accessibility of types named in dependent bases are
8666 looked up from. */
8669 /* Substitute into each of the bases to determine the actual
8670 basetypes. */
8672 {
8673 tree base;
8679 {
8680 expanded_bases =
8687 }
8690 {
8692 /* Extract the already-expanded base class. */
8694 else
8695 /* Substitute to figure out the base class. */
8697 NULL_TREE);
8705 }
8706 }
8708 /* The list is now in reverse order; correct that. */
8713 }
8714 /* Now call xref_basetypes to set up all the base-class
8715 information. */
8723 /* Now that our base classes are set up, enter the scope of the
8724 class, so that name lookups into base classes, etc. will work
8725 correctly. This is precisely analogous to what we do in
8726 begin_class_definition when defining an ordinary non-template
8727 class, except we also need to push the enclosing classes. */
8730 /* Now members are processed in the order of declaration. */
8733 {
8737 {
8739 {
8740 /* Build new CLASSTYPE_NESTED_UTDS. */
8742 tree newtag;
8748 /* If the member is a class template, then -- even after
8749 substitution -- there may be dependent types in the
8750 template argument list for the class. We increment
8751 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
8752 that function will assume that no types are dependent
8753 when outside of a template. */
8763 {
8767 /* Unfortunately, lookup_template_class sets
8768 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
8769 instantiation (i.e., for the type of a member
8770 template class nested within a template class.)
8771 This behavior is required for
8772 maybe_process_partial_specialization to work
8773 correctly, but is not accurate in this case;
8774 the TAG is not an instantiation of anything.
8775 (The corresponding TEMPLATE_DECL is an
8776 instantiation, but the TYPE is not.) */
8779 /* Now, we call pushtag to put this NEWTAG into the scope of
8780 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
8781 pushtag calling push_template_decl. We don't have to do
8782 this for enums because it will already have been done in
8783 tsubst_enum. */
8787 }
8788 }
8791 {
8792 /* Build new TYPE_METHODS. */
8793 tree r;
8802 /* Instantiate members marked with attribute used. */
8805 }
8806 else
8807 {
8808 /* Build new TYPE_FIELDS. */
8810 {
8811 tree condition;
8814 condition =
8824 }
8826 {
8827 tree r;
8829 /* The file and line for this declaration, to
8830 assist in error message reporting. Since we
8831 called push_tinst_level above, we don't need to
8832 restore these. */
8841 {
8842 /* In [temp.inst]:
8844 [t]he initialization (and any associated
8845 side-effects) of a static data member does
8846 not occur unless the static data member is
8847 itself used in a way that requires the
8848 definition of the static data member to
8849 exist.
8851 Therefore, we do not substitute into the
8852 initialized for the static data member here. */
8853 finish_static_data_member_decl
8859 /* Instantiate members marked with attribute used. */
8862 }
8864 {
8865 /* Determine whether R has a valid type and can be
8866 completed later. If R is invalid, then it is
8867 replaced by error_mark_node so that it will not be
8868 added to TYPE_FIELDS. */
8874 {
8877 }
8878 }
8880 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
8881 such a thing will already have been added to the field
8882 list by tsubst_enum in finish_member_declaration in the
8883 CLASSTYPE_NESTED_UTDS case above. */
8887 {
8890 }
8891 }
8892 }
8893 }
8894 else
8895 {
8898 {
8899 /* Build new CLASSTYPE_FRIEND_CLASSES. */
8905 {
8906 /* template <class T> friend class C; */
8909 }
8911 {
8912 /* template <class T> friend class C::D; */
8918 }
8921 {
8922 /* This could be either
8924 friend class T::C;
8926 when dependent_type_p is false or
8928 template <class U> friend class T::C;
8930 otherwise. */
8933 /* Bump processing_template_decl for correct
8934 dependent_type_p calculation. */
8939 }
8942 {
8943 /* friend class C;
8945 where C hasn't been declared yet. Let's lookup name
8946 from namespace scope directly, bypassing any name that
8947 come from dependent base class. */
8950 /* The call to xref_tag_from_type does injection for friend
8951 classes. */
8953 friend_type =
8957 }
8959 /* friend class C<T>; */
8962 /* Otherwise it's
8964 friend class C;
8966 where C is already declared or
8968 friend class C<int>;
8970 We don't have to do anything in these cases. */
8973 /* Trick make_friend_class into realizing that the friend
8974 we're adding is a template, not an ordinary class. It's
8975 important that we use make_friend_class since it will
8976 perform some error-checking and output cross-reference
8977 information. */
8985 }
8986 else
8987 {
8988 /* Build new DECL_FRIENDLIST. */
8989 tree r;
8991 /* The file and line for this declaration, to
8992 assist in error message reporting. Since we
8993 called push_tinst_level above, we don't need to
8994 restore these. */
8998 {
9001 }
9006 {
9009 }
9010 }
9011 }
9012 }
9015 {
9018 {
9021 /* We need to instantiate the capture list from the template
9022 after we've instantiated the closure members, but before we
9023 consider adding the conversion op. Also keep any captures
9024 that may have been added during instantiation of the op(). */
9026 tree tmpl_cap
9035 }
9036 else
9038 }
9040 /* Set the file and line number information to whatever is given for
9041 the class itself. This puts error messages involving generated
9042 implicit functions at a predictable point, and the same point
9043 that would be used for non-template classes. */
9050 /* We don't instantiate default arguments for member functions. 14.7.1:
9052 The implicit instantiation of a class template specialization causes
9053 the implicit instantiation of the declarations, but not of the
9054 definitions or default arguments, of the class member functions,
9055 member classes, static data members and member templates.... */
9057 /* Some typedefs referenced from within the template code need to be access
9058 checked at template instantiation time, i.e now. These types were
9059 added to the template at parsing time. Let's get those and perform
9060 the access checks then. */
9070 /* The vtable for a template class can be emitted in any translation
9071 unit in which the class is instantiated. When there is no key
9072 method, however, finish_struct_1 will already have added TYPE to
9073 the keyed_classes list. */
9078 }
9080 /* Wrapper for instantiate_class_template_1. */
9082 tree
9084 {
9085 tree ret;
9090 }
9092 static tree
9094 {
9095 tree r;
9101 else
9102 {
9109 /* Preserve the raw-reference nature of T. */
9113 }
9115 }
9117 /* Given a function parameter pack TMPL_PARM and some function parameters
9118 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
9119 and set *SPEC_P to point at the next point in the list. */
9121 static tree
9123 {
9124 /* Collect all of the extra "packed" parameters into an
9125 argument pack. */
9126 tree parmvec;
9127 tree parmtypevec;
9138 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
9143 {
9146 }
9148 /* Build the argument packs. */
9155 }
9157 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9158 NONTYPE_ARGUMENT_PACK. */
9160 static tree
9162 {
9164 }
9166 /* Return true iff the Ith element of the argument pack ARG_PACK is a
9167 pack expansion. */
9169 static bool
9171 {
9176 }
9179 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
9181 static tree
9183 {
9190 }
9192 /* This is a subroutine of tsubst_pack_expansion.
9194 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
9195 mechanism to store the (non complete list of) arguments of the
9196 substitution and return a non substituted pack expansion, in order
9197 to wait for when we have enough arguments to really perform the
9198 substitution. */
9200 static bool
9204 {
9210 {
9213 parm_pack;
9215 {
9220 else
9222 }
9224 /* If one pack has an expansion and another pack has a normal
9225 argument or if one pack has an empty argument another one
9226 hasn't then tsubst_pack_expansion cannot perform the
9227 substitution and need to fall back on the
9228 PACK_EXPANSION_EXTRA mechanism. */
9232 }
9234 }
9236 /* [temp.variadic]/6 says that:
9238 The instantiation of a pack expansion [...]
9239 produces a list E1,E2, ..., En, where N is the number of elements
9240 in the pack expansion parameters.
9242 This subroutine of tsubst_pack_expansion produces one of these Ei.
9244 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
9245 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
9246 PATTERN, and each TREE_VALUE is its corresponding argument pack.
9247 INDEX is the index 'i' of the element Ei to produce. ARGS,
9248 COMPLAIN, and IN_DECL are the same parameters as for the
9249 tsubst_pack_expansion function.
9251 The function returns the resulting Ei upon successful completion,
9252 or error_mark_node.
9254 Note that this function possibly modifies the ARGS parameter, so
9255 it's the responsibility of the caller to restore it. */
9257 static tree
9259 tree parm_packs,
9261 tree args /* This parm gets
9263 tsubst_flags_t complain,
9264 tree in_decl)
9265 {
9266 tree t;
9269 /* For each parameter pack, change the substitution of the parameter
9270 pack to the ith argument in its argument pack, then expand the
9271 pattern. */
9273 {
9278 ith_elem_is_expansion |=
9281 /* Select the Ith argument from the pack. */
9283 {
9285 {
9289 }
9290 else
9292 }
9293 else
9294 {
9299 {
9301 /* Update the corresponding argument. */
9303 }
9304 else
9305 /* Re-use the ARGUMENT_PACK_SELECT. */
9307 }
9309 }
9311 /* Substitute into the PATTERN with the (possibly altered)
9312 arguments. */
9316 else
9319 /* If the Ith argument pack element is a pack expansion, then
9320 the Ith element resulting from the substituting is going to
9321 be a pack expansion as well. */
9326 }
9328 /* Substitute ARGS into T, which is an pack expansion
9329 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
9330 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
9331 (if only a partial substitution could be performed) or
9332 ERROR_MARK_NODE if there was an error. */
9333 tree
9335 tree in_decl)
9336 {
9337 tree pattern;
9341 tree result;
9349 /* Add in any args remembered from an earlier partial instantiation. */
9354 /* Determine the argument packs that will instantiate the parameter
9355 packs used in the expansion expression. While we're at it,
9356 compute the number of arguments to be expanded and make sure it
9357 is consistent. */
9360 {
9367 {
9371 else
9374 }
9376 {
9379 else
9380 {
9381 /* We can't rely on local_specializations for a parameter
9382 name used later in a function declaration (such as in a
9383 late-specified return type). Even if it exists, it might
9384 have the wrong value for a recursive call. Just make a
9385 dummy decl, since it's only used for its type. */
9388 /* Partial instantiation of the parm_pack, we can't build
9389 up an argument pack yet. */
9391 else
9394 }
9395 }
9396 else
9397 {
9403 }
9410 /* This can only happen if we forget to expand an argument
9411 pack somewhere else. Just return an error, silently. */
9412 {
9416 }
9419 {
9423 /* Don't bother trying to do a partial substitution with
9424 incomplete packs; we'll try again after deduction. */
9431 {
9437 pattern);
9438 else
9441 pattern);
9443 }
9445 /* Keep track of the parameter packs and their corresponding
9446 argument packs. */
9449 }
9450 else
9451 {
9452 /* We can't substitute for this parameter pack. We use a flag as
9453 well as the missing_level counter because function parameter
9454 packs don't have a level. */
9456 }
9457 }
9459 /* We cannot expand this expansion expression, because we don't have
9460 all of the argument packs we need. */
9462 {
9463 /* We got some full packs, but we can't substitute them in until we
9464 have values for all the packs. So remember these until then. */
9469 }
9471 {
9472 /* There were no real arguments, we're just replacing a parameter
9473 pack with another version of itself. Substitute into the
9474 pattern and return a PACK_EXPANSION_*. The caller will need to
9475 deal with that. */
9479 else
9483 }
9488 {
9489 /* We're in a late-specified return type, so create our own local
9490 specializations map; the current map is either NULL or (in the
9491 case of recursive unification) might have bindings that we don't
9492 want to use or alter. */
9495 }
9497 /* For each argument in each argument pack, substitute into the
9498 pattern. */
9501 {
9503 i,
9505 in_decl);
9508 {
9511 }
9512 }
9514 /* Update ARGS to restore the substitution from parameter packs to
9515 their argument packs. */
9517 {
9522 else
9523 {
9531 /* Update the corresponding argument. */
9535 else
9537 }
9538 }
9541 {
9544 }
9547 }
9549 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
9550 TMPL. We do this using DECL_PARM_INDEX, which should work even with
9551 parameter packs; all parms generated from a function parameter pack will
9552 have the same DECL_PARM_INDEX. */
9554 tree
9556 {
9558 tree patparm;
9561 {
9567 }
9568 else
9569 {
9574 }
9577 }
9579 /* Substitute ARGS into the vector or list of template arguments T. */
9581 static tree
9583 {
9595 {
9597 tree new_arg;
9602 {
9603 /* Substitute into an expansion expression. */
9607 /* Add to the expanded length adjustment the number of
9608 expanded arguments. We subtract one from this
9609 measurement, because the argument pack expression
9610 itself is already counted as 1 in
9611 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
9612 the argument pack is empty. */
9614 }
9616 {
9617 /* Substitute into each of the arguments. */
9623 new_arg,
9637 }
9638 }
9639 else
9648 }
9653 /* Make space for the expanded arguments coming from template
9654 argument packs. */
9656 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
9657 arguments for a member template.
9658 In that case each TREE_VEC in ORIG_T represents a level of template
9659 arguments, and ORIG_T won't carry any non defaulted argument count.
9660 It will rather be the nested TREE_VECs that will carry one.
9661 In other words, ORIG_T carries a non defaulted argument count only
9662 if it doesn't contain any nested TREE_VEC. */
9664 {
9668 }
9670 {
9674 {
9677 /* Now expand the template argument pack "in place". */
9680 }
9681 else
9682 {
9684 out++;
9685 }
9686 }
9689 }
9691 /* Return the result of substituting ARGS into the template parameters
9692 given by PARMS. If there are m levels of ARGS and m + n levels of
9693 PARMS, then the result will contain n levels of PARMS. For
9694 example, if PARMS is `template <class T> template <class U>
9695 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
9696 result will be `template <int*, double, class V>'. */
9698 static tree
9700 {
9704 /* When substituting into a template, we must set
9705 PROCESSING_TEMPLATE_DECL as the template parameters may be
9706 dependent if they are based on one-another, and the dependency
9707 predicates are short-circuit outside of templates. */
9714 {
9715 tree new_vec =
9720 {
9721 tree tuple;
9733 }
9739 }
9744 }
9746 /* Return the result of substituting ARGS into one template parameter
9747 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
9748 parameter and which TREE_PURPOSE is the default argument of the
9749 template parameter. */
9751 static tree
9753 {
9774 }
9776 /* Substitute the ARGS into the indicated aggregate (or enumeration)
9777 type T. If T is not an aggregate or enumeration type, it is
9778 handled as if by tsubst. IN_DECL is as for tsubst. If
9779 ENTERING_SCOPE is nonzero, T is the context for a template which
9780 we are presently tsubst'ing. Return the substituted value. */
9782 static tree
9784 tree args,
9785 tsubst_flags_t complain,
9786 tree in_decl,
9788 {
9793 {
9798 /* Else fall through. */
9802 {
9803 tree argvec;
9804 tree context;
9805 tree r;
9809 /* In "sizeof(X<I>)" we need to evaluate "I". */
9815 /* First, determine the context for the type we are looking
9816 up. */
9819 {
9822 /* If context is a nested class inside a class template,
9823 it may still need to be instantiated (c++/33959). */
9825 }
9827 /* Then, figure out what arguments are appropriate for the
9828 type we are trying to find. For example, given:
9830 template <class T> struct S;
9831 template <class T, class U> void f(T, U) { S<U> su; }
9833 and supposing that we are instantiating f<int, double>,
9834 then our ARGS will be {int, double}, but, when looking up
9835 S we only want {double}. */
9840 else
9841 {
9845 }
9851 }
9852 else
9853 /* This is not a template type, so there's nothing to do. */
9858 }
9859 }
9861 /* Substitute into the default argument ARG (a default argument for
9862 FN), which has the indicated TYPE. */
9864 tree
9866 {
9871 /* This can happen in invalid code. */
9875 /* This default argument came from a template. Instantiate the
9876 default argument here, not in tsubst. In the case of
9877 something like:
9879 template <class T>
9880 struct S {
9881 static T t();
9882 void f(T = t());
9883 };
9885 we must be careful to do name lookup in the scope of S<T>,
9886 rather than in the current class. */
9888 /* The "this" pointer is not valid in a default argument. */
9890 {
9895 }
9898 /* The default argument expression may cause implicitly defined
9899 member functions to be synthesized, which will result in garbage
9900 collection. We must treat this situation as if we were within
9901 the body of function so as to avoid collecting live data on the
9902 stack. */
9910 /* Restore the "this" pointer. */
9912 {
9915 }
9921 /* Make sure the default argument is reasonable. */
9927 }
9929 /* Substitute into all the default arguments for FN. */
9931 static void
9933 {
9934 tree arg;
9935 tree tmpl_args;
9939 /* If this function is not yet instantiated, we certainly don't need
9940 its default arguments. */
9943 /* Don't do this again for clones. */
9948 arg;
9954 }
9956 /* Substitute the ARGS into the T, which is a _DECL. Return the
9957 result of the substitution. Issue error and warning messages under
9958 control of COMPLAIN. */
9960 static tree
9962 {
9963 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
9964 location_t saved_loc;
9969 /* Set the filename and linenumber to improve error-reporting. */
9974 {
9976 {
9977 /* We can get here when processing a member function template,
9978 member class template, or template template parameter. */
9980 tree spec;
9981 tree tmpl_args;
9982 tree full_args;
9985 {
9986 /* Template template parameter is treated here. */
9990 /* If we get a real template back, return it. This can happen in
9991 the context of most_specialized_class. */
10003 complain);
10006 }
10008 /* We might already have an instance of this template.
10009 The ARGS are for the surrounding class type, so the
10010 full args contain the tsubst'd args for the context,
10011 plus the innermost args from the template decl. */
10015 /* Because this is a template, the arguments will still be
10016 dependent, even after substitution. If
10017 PROCESSING_TEMPLATE_DECL is not set, the dependency
10018 predicates will short-circuit. */
10026 /* If this is a default template template argument,
10027 tsubst might not have changed anything. */
10034 {
10037 }
10039 /* Make a new template decl. It will be similar to the
10040 original, but will record the current template arguments.
10041 We also create a new function declaration, which is just
10042 like the old one, but points to this new template, rather
10043 than the old one. */
10052 {
10053 tree new_type;
10065 }
10066 else
10067 {
10068 tree new_decl;
10080 }
10086 /* The template parameters for this new template are all the
10087 template parameters for the old template, except the
10088 outermost level of parameters. */
10091 complain);
10097 /* Record this non-type partial instantiation. */
10101 }
10105 {
10106 tree ctx;
10109 tree gen_tmpl;
10110 tree type;
10115 /* Nobody should be tsubst'ing into non-template functions. */
10119 {
10120 tree spec;
10123 /* If T is not dependent, just return it. We have to
10124 increment PROCESSING_TEMPLATE_DECL because
10125 value_dependent_expression_p assumes that nothing is
10126 dependent when PROCESSING_TEMPLATE_DECL is zero. */
10133 /* Calculate the most general template of which R is a
10134 specialization, and the complete set of arguments used to
10135 specialize R. */
10138 (DECL_TEMPLATE_RESULT
10144 /* Check to see if we already have this specialization. */
10149 {
10152 }
10154 /* We can see more levels of arguments than parameters if
10155 there was a specialization of a member template, like
10156 this:
10158 template <class T> struct S { template <class U> void f(); }
10159 template <> template <class U> void S<int>::f(U);
10161 Here, we'll be substituting into the specialization,
10162 because that's where we can find the code we actually
10163 want to generate, but we'll have enough arguments for
10164 the most general template.
10166 We also deal with the peculiar case:
10168 template <class T> struct S {
10169 template <class U> friend void f();
10170 };
10171 template <class U> void f() {}
10172 template S<int>;
10173 template void f<double>();
10175 Here, the ARGS for the instantiation of will be {int,
10176 double}. But, we only need as many ARGS as there are
10177 levels of template parameters in CODE_PATTERN. We are
10178 careful not to get fooled into reducing the ARGS in
10179 situations like:
10181 template <class T> struct S { template <class U> void f(U); }
10182 template <class T> template <> void S<T>::f(int) {}
10184 which we can spot because the pattern will be a
10185 specialization in this case. */
10187 parms_depth =
10192 }
10193 else
10194 {
10195 /* This special case arises when we have something like this:
10197 template <class T> struct S {
10198 friend void f<int>(int, double);
10199 };
10201 Here, the DECL_TI_TEMPLATE for the friend declaration
10202 will be an IDENTIFIER_NODE. We are being called from
10203 tsubst_friend_function, and we want only to create a
10204 new decl (R) with appropriate types so that we can call
10205 determine_specialization. */
10207 }
10210 {
10213 else
10217 }
10218 else
10219 {
10222 }
10227 /* If we hit excessive deduction depth, the type is bogus even if
10228 it isn't error_mark_node, so don't build a decl. */
10232 /* We do NOT check for matching decls pushed separately at this
10233 point, as they may not represent instantiations of this
10234 template, and in any case are considered separate under the
10235 discrete model. */
10239 /* Clear out the mangled name and RTL for the instantiation. */
10242 /* Leave DECL_INITIAL set on deleted instantiations. */
10248 /* Type-conversion operator. Reconstruct the name, in
10249 case it's the name of one of the template's parameters. */
10259 /* If this is an instantiation of a function with internal
10260 linkage, we already know what object file linkage will be
10261 assigned to the instantiation. */
10270 /* We'll re-clone as appropriate in instantiate_template. */
10273 /* If we aren't complaining now, return on error before we register
10274 the specialization so that we'll complain eventually. */
10280 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
10281 this in the special friend case mentioned above where
10282 GEN_TMPL is NULL. */
10284 {
10289 tree new_r
10292 /* We instantiated this while substituting into
10293 the type earlier (template/friend54.C). */
10296 /* We're not supposed to instantiate default arguments
10297 until they are called, for a template. But, for a
10298 declaration like:
10300 template <class T> void f ()
10301 { extern void g(int i = T()); }
10303 we should do the substitution when the template is
10304 instantiated. We handle the member function case in
10305 instantiate_class_template since the default arguments
10306 might refer to other members of the class. */
10311 }
10312 else
10315 /* Copy the list of befriending classes. */
10319 {
10323 in_decl);
10324 }
10327 {
10333 /* If this is an instantiation of a member template, clone it.
10334 If it isn't, that'll be handled by
10335 clone_constructors_and_destructors. */
10338 }
10349 /* Possibly limit visibility based on template args. */
10352 {
10356 }
10364 }
10368 {
10376 {
10377 /* If there is a local specialization that isn't a
10378 parameter pack, it means that we're doing a "simple"
10379 substitution from inside tsubst_pack_expansion. Just
10380 return the local specialization (which will be a single
10381 parm). */
10388 /* Expand the TYPE_PACK_EXPANSION that provides the types for
10389 the parameters in this function parameter pack. */
10393 {
10396 /* Zero-length parameter packs are boring. Just substitute
10397 into the chain. */
10401 }
10402 else
10403 {
10404 /* All we did was update the type. Make a note of that. */
10407 }
10408 }
10410 /* Loop through all of the parameter's we'll build. When T is
10411 a function parameter pack, LEN is the number of expanded
10412 types in EXPANDED_TYPES; otherwise, LEN is 1. */
10415 {
10422 /* We're on the Ith parameter of the function parameter
10423 pack. */
10424 {
10425 /* An argument of a function parameter pack is not a parameter
10426 pack. */
10429 /* Get the Ith type. */
10432 /* Rename the parameter to include the index. */
10435 }
10437 /* We're dealing with a normal parameter. */
10445 {
10448 else
10451 }
10461 /* Keep track of the first new parameter we
10462 generate. That's what will be returned to the
10463 caller. */
10467 /* Build a proper chain of parameters when substituting
10468 into a function parameter pack. */
10471 }
10473 /* If cp_unevaluated_operand is set, we're just looking for a
10474 single dummy parameter, so don't keep going. */
10479 /* FIRST_R contains the start of the chain we've built. */
10481 }
10485 {
10486 tree type;
10496 /* For bit-fields, DECL_INITIAL gives the number of bits. For
10497 non-bit-fields DECL_INITIAL is a non-static data member
10498 initializer, which gets deferred instantiation. */
10504 {
10505 /* Set up DECL_TEMPLATE_INFO so that we can get at the
10506 NSDMI in perform_member_init. Still set DECL_INITIAL
10507 so that we know there is one. */
10512 }
10513 /* We don't have to set DECL_CONTEXT here; it is set by
10514 finish_member_declaration. */
10521 }
10525 /* We reach here only for member using decls. We also need to check
10526 uses_template_parms because DECL_DEPENDENT_P is not set for a
10527 using-declaration that designates a member of the current
10528 instantiation (c++/53549). */
10531 {
10538 else
10539 {
10542 }
10543 }
10544 else
10545 {
10548 }
10553 {
10556 tree spec;
10558 tree ctx;
10564 {
10565 /* If this is the canonical decl, we don't have to
10566 mess with instantiations, and often we can't (for
10567 typename, template type parms and such). Note that
10568 TYPE_NAME is not correct for the above test if
10569 we've copied the type for a typedef. */
10575 }
10577 /* Check to see if we already have the specialization we
10578 need. */
10581 {
10582 /* T is a static data member or namespace-scope entity.
10583 We have to substitute into namespace-scope variables
10584 (even though such entities are never templates) because
10585 of cases like:
10587 template <class T> void f() { extern T t; }
10589 where the entity referenced is not known until
10590 instantiation time. */
10594 {
10596 complain,
10598 /* If CTX is unchanged, then T is in fact the
10599 specialization we want. That situation occurs when
10600 referencing a static data member within in its own
10601 class. We can use pointer equality, rather than
10602 same_type_p, because DECL_CONTEXT is always
10603 canonical... */
10606 /* ... unless T is a member template; in which
10607 case our caller can be willing to create a
10608 specialization of that template represented
10609 by T. */
10613 }
10616 {
10624 }
10625 }
10626 else
10627 {
10628 /* A local variable. */
10630 /* Subsequent calls to pushdecl will fill this in. */
10633 }
10634 /* If we already have the specialization we need, there is
10635 nothing more to do. */
10637 {
10640 }
10643 {
10644 /* Just use name lookup to find a member alias for an anonymous
10645 union, but then add it to the hash table. */
10650 }
10652 /* Create a new node for the specialization we need. */
10655 {
10658 else
10665 }
10667 {
10668 /* Even if the original location is out of scope, the
10669 newly substituted one is not. */
10676 {
10677 /* It may seem that this case cannot occur, since:
10679 typedef void f();
10680 void g() { f x; }
10682 declares a function, not a variable. However:
10684 typedef void f();
10685 template <typename T> void g() { T t; }
10686 template void g<f>();
10688 is an attempt to declare a variable with function
10689 type. */
10691 /* R is not yet sufficiently initialized, so we
10692 just use its name. */
10695 }
10697 /* Wait until cp_finish_decl to set this again, to handle
10698 circular dependency (template/instantiate6.C). */
10703 {
10708 {
10711 }
10713 }
10714 }
10720 /* Clear out the mangled name and RTL for the instantiation. */
10724 /* The initializer must not be expanded until it is required;
10725 see [temp.inst]. */
10731 {
10732 /* Possibly limit visibility based on template args. */
10735 {
10739 }
10741 }
10744 {
10745 /* A static data member declaration is always marked
10746 external when it is declared in-class, even if an
10747 initializer is present. We mimic the non-template
10748 processing here. */
10754 }
10756 {
10757 /* We're substituting this var in a decltype outside of its
10758 scope, such as for a lambda return type. Don't add it to
10759 local_specializations, do perform auto deduction. */
10762 {
10763 tree init
10769 }
10770 }
10771 else
10780 /* Preserve a typedef that names a type. */
10782 {
10785 }
10788 }
10793 }
10794 #undef RETURN
10796 out:
10797 /* Restore the file and line information. */
10801 }
10803 /* Substitute into the ARG_TYPES of a function type.
10804 If END is a TREE_CHAIN, leave it and any following types
10805 un-substituted. */
10807 static tree
10809 tree args,
10810 tree end,
10811 tsubst_flags_t complain,
10812 tree in_decl)
10813 {
10814 tree remaining_arg_types;
10818 tree default_arg;
10829 {
10830 /* For a pack expansion, perform substitution on the
10831 entire expression. Later on, we'll handle the arguments
10832 one-by-one. */
10837 /* So that we'll spin through the parameters, one by one. */
10839 else
10840 {
10841 /* We only partially substituted into the parameter
10842 pack. Our type is TYPE_PACK_EXPANSION. */
10845 }
10846 }
10859 {
10861 {
10865 }
10867 }
10868 /* DR 657. */
10872 /* Do array-to-pointer, function-to-pointer conversion, and ignore
10873 top-level qualifiers as required. */
10876 /* We do not substitute into default arguments here. The standard
10877 mandates that they be instantiated only when needed, which is
10878 done in build_over_call. */
10882 {
10883 /* We've instantiated a template before its default arguments
10884 have been parsed. This can happen for a nested template
10885 class, and is not an error unless we require the default
10886 argument in a call of this function. */
10887 remaining_arg_types =
10890 }
10891 else
10892 remaining_arg_types =
10894 }
10897 }
10899 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
10900 *not* handle the exception-specification for FNTYPE, because the
10901 initial substitution of explicitly provided template parameters
10902 during argument deduction forbids substitution into the
10903 exception-specification:
10905 [temp.deduct]
10907 All references in the function type of the function template to the
10908 corresponding template parameters are replaced by the specified tem-
10909 plate argument values. If a substitution in a template parameter or
10910 in the function type of the function template results in an invalid
10911 type, type deduction fails. [Note: The equivalent substitution in
10912 exception specifications is done only when the function is instanti-
10913 ated, at which point a program is ill-formed if the substitution
10914 results in an invalid type.] */
10916 static tree
10918 tree args,
10919 tsubst_flags_t complain,
10920 tree in_decl)
10921 {
10922 tree return_type;
10923 tree arg_types;
10924 tree fntype;
10926 /* The TYPE_CONTEXT is not used for function/method types. */
10929 /* Substitute the return type. */
10933 /* DR 486 clarifies that creation of a function type with an
10934 invalid return type is a deduction failure. */
10937 {
10939 {
10942 else
10944 }
10946 }
10947 /* And DR 657. */
10951 /* Substitute the argument types. */
10957 /* Construct a new type node and return it. */
10959 {
10962 }
10963 else
10964 {
10967 {
10968 /* [temp.deduct]
10970 Type deduction may fail for any of the following
10971 reasons:
10973 -- Attempting to create "pointer to member of T" when T
10974 is not a class type. */
10977 r);
10979 }
10983 }
10987 }
10989 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
10990 ARGS into that specification, and return the substituted
10991 specification. If there is no specification, return NULL_TREE. */
10993 static tree
10995 tree args,
10996 tsubst_flags_t complain,
10997 tree in_decl,
10999 {
11000 tree specs;
11001 tree new_specs;
11006 {
11007 /* A noexcept-specifier. */
11012 {
11013 /* Defer instantiation of noexcept-specifiers to avoid
11014 excessive instantiations (c++/49107). */
11017 {
11018 /* We already partially instantiated this member template,
11019 so combine the new args with the old. */
11024 }
11025 else
11026 {
11029 }
11030 }
11031 else
11032 new_specs = tsubst_copy_and_build
11036 }
11038 {
11041 else
11043 {
11044 tree spec;
11049 {
11050 /* Expand the pack expansion type. */
11053 in_decl);
11059 else
11060 {
11061 /* We're substituting into a member template, so
11062 we got a TYPE_PACK_EXPANSION back. Add that
11063 expansion and move on. */
11067 expanded_specs,
11068 complain);
11071 }
11072 }
11075 {
11078 else
11083 complain);
11084 }
11087 }
11088 }
11090 }
11092 /* Take the tree structure T and replace template parameters used
11093 therein with the argument vector ARGS. IN_DECL is an associated
11094 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
11095 Issue error and warning messages under control of COMPLAIN. Note
11096 that we must be relatively non-tolerant of extensions here, in
11097 order to preserve conformance; if we allow substitutions that
11098 should not be allowed, we may allow argument deductions that should
11099 not succeed, and therefore report ambiguous overload situations
11100 where there are none. In theory, we could allow the substitution,
11101 but indicate that it should have failed, and allow our caller to
11102 make sure that the right thing happens, but we don't try to do this
11103 yet.
11105 This function is used for dealing with types, decls and the like;
11106 for expressions, use tsubst_expr or tsubst_copy. */
11108 tree
11110 {
11133 else
11138 /* Reuse typedefs. We need to do this to handle dependent attributes,
11139 such as attribute aligned. */
11142 {
11146 {
11147 /* DECL represents an alias template and we want to
11148 instantiate it. */
11152 }
11156 {
11160 }
11165 else
11166 /* The typedef is from a non-template context. */
11170 {
11172 r = cp_build_qualified_type_real
11176 }
11177 else
11178 {
11179 /* We don't have an instantiation yet, so drop the typedef. */
11184 }
11185 }
11198 {
11224 {
11230 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
11231 needed. */
11237 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
11238 with TREE_SIDE_EFFECTS that indicates this is not an integral
11239 constant expression. */
11242 {
11245 }
11248 }
11254 {
11267 {
11271 {
11272 /* See through ARGUMENT_PACK_SELECT arguments. */
11274 /* If the selected argument is an expansion E, that most
11275 likely means we were called from
11276 gen_elem_of_pack_expansion_instantiation during the
11277 substituting of pack an argument pack (which Ith
11278 element is a pack expansion, where I is
11279 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
11280 In this case, the Ith element resulting from this
11281 substituting is going to be a pack expansion, which
11282 pattern is the pattern of E. Let's return the
11283 pattern of E, and
11284 gen_elem_of_pack_expansion_instantiation will
11285 build the resulting pack expansion from it. */
11288 }
11289 }
11294 {
11296 /* If ARG is an argument pack, we don't actually want to
11297 perform a substitution here, because substitutions
11298 for argument packs are only done
11299 element-by-element. We can get to this point when
11300 substituting the type of a non-type template
11301 parameter pack, when that type actually contains
11302 template parameter packs from an outer template, e.g.,
11304 template<typename... Types> struct A {
11305 template<Types... Values> struct B { };
11306 }; */
11310 {
11316 return cp_build_qualified_type_real
11318 }
11320 {
11321 /* We are processing a type constructed from a
11322 template template parameter. */
11333 /* Consider this code:
11335 template <template <class> class Template>
11336 struct Internal {
11337 template <class Arg> using Bind = Template<Arg>;
11338 };
11340 template <template <class> class Template, class Arg>
11341 using Instantiate = Template<Arg>; //#0
11343 template <template <class> class Template,
11344 class Argument>
11345 using Bind =
11346 Instantiate<Internal<Template>::template Bind,
11347 Argument>; //#1
11349 When #1 is parsed, the
11350 BOUND_TEMPLATE_TEMPLATE_PARM representing the
11351 parameter `Template' in #0 matches the
11352 UNBOUND_CLASS_TEMPLATE representing the argument
11353 `Internal<Template>::template Bind'; We then want
11354 to assemble the type `Bind<Argument>' that can't
11355 be fully created right now, because
11356 `Internal<Template>' not being complete, the Bind
11357 template cannot be looked up in that context. So
11358 we need to "store" `Bind<Argument>' for later
11359 when the context of Bind becomes complete. Let's
11360 store that in a TYPENAME_TYPE. */
11364 argvec),
11365 typename_type,
11366 complain);
11368 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
11369 are resolving nested-types in the signature of a
11370 member function templates. Otherwise ARG is a
11371 TEMPLATE_DECL and is the real template to be
11372 instantiated. */
11380 complain);
11381 return cp_build_qualified_type_real
11383 }
11384 else
11385 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
11387 }
11390 /* This can happen during the attempted tsubst'ing in
11391 unify. This means that we don't yet have any information
11392 about the template parameter in question. */
11395 /* Early in template argument deduction substitution, we don't
11396 want to reduce the level of 'auto', or it will be confused
11397 with a normal template parm in subsequent deduction. */
11401 /* If we get here, we must have been looking at a parm for a
11402 more deeply nested template. Make a new version of this
11403 template parameter, but with a lower level. */
11405 {
11410 {
11412 r = cp_build_qualified_type_real
11416 }
11417 else
11418 {
11429 /* We have reduced the level of the template
11430 template parameter, but not the levels of its
11431 template parameters, so canonical_type_parameter
11432 will not be able to find the canonical template
11433 template parameter for this level. Thus, we
11434 require structural equality checking to compare
11435 TEMPLATE_TEMPLATE_PARMs. */
11439 else
11443 {
11451 }
11452 }
11461 }
11464 }
11467 {
11475 {
11479 }
11482 {
11486 }
11489 {
11493 }
11499 }
11502 /* We should never be tsubsting a binfo. */
11506 /* A vector of template arguments. */
11512 {
11516 /* [temp.deduct]
11518 Type deduction may fail for any of the following
11519 reasons:
11521 -- Attempting to create a pointer to reference type.
11522 -- Attempting to create a reference to a reference type or
11523 a reference to void.
11525 Core issue 106 says that creating a reference to a reference
11526 during instantiation is no longer a cause for failure. We
11527 only enforce this check in strict C++98 mode. */
11531 {
11534 /* We keep track of the last time we issued this error
11535 message to avoid spewing a ton of messages during a
11536 single bad template instantiation. */
11539 {
11544 else
11547 }
11550 }
11552 {
11556 }
11558 /* In C++0x, during template argument substitution, when there is an
11559 attempt to create a reference to a reference type, reference
11560 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
11562 "If a template-argument for a template-parameter T names a type
11563 that is a reference to a type A, an attempt to create the type
11564 'lvalue reference to cv T' creates the type 'lvalue reference to
11565 A,' while an attempt to create the type type rvalue reference to
11566 cv T' creates the type T"
11567 */
11568 r = cp_build_reference_type
11571 else
11576 /* Will this ever be needed for TYPE_..._TO values? */
11580 }
11582 {
11585 {
11586 /* [temp.deduct]
11588 Type deduction may fail for any of the following
11589 reasons:
11591 -- Attempting to create "pointer to member of T" when T
11592 is not a class type. */
11596 }
11598 {
11602 }
11604 {
11608 }
11611 {
11612 /* The type of the implicit object parameter gets its
11613 cv-qualifiers from the FUNCTION_TYPE. */
11614 tree memptr;
11618 complain);
11619 }
11620 else
11623 complain);
11624 }
11627 {
11628 tree fntype;
11629 tree specs;
11634 /* Substitute the exception specification. */
11642 }
11644 {
11649 /* As an optimization, we avoid regenerating the array type if
11650 it will obviously be the same as T. */
11654 /* These checks should match the ones in grokdeclarator.
11656 [temp.deduct]
11658 The deduction may fail for any of the following reasons:
11660 -- Attempting to create an array with an element type that
11661 is void, a function type, or a reference type, or [DR337]
11662 an abstract class type. */
11666 {
11670 }
11678 {
11681 }
11684 }
11687 {
11697 {
11701 }
11703 {
11704 /* Normally, make_typename_type does not require that the CTX
11705 have complete type in order to allow things like:
11707 template <class T> struct S { typename S<T>::X Y; };
11709 But, such constructs have already been resolved by this
11710 point, so here CTX really should have complete type, unless
11711 it's a partial instantiation. */
11714 {
11718 }
11719 }
11726 {
11729 }
11732 {
11734 {
11738 else
11740 }
11742 {
11746 else
11748 }
11749 }
11751 return cp_build_qualified_type_real
11753 }
11756 {
11768 }
11771 {
11772 tree type;
11788 complain);
11789 }
11792 {
11793 tree type;
11809 else
11810 type = finish_decltype_type
11815 complain);
11816 }
11819 {
11823 }
11827 {
11829 tree packed_out =
11831 args,
11832 complain,
11833 in_decl);
11836 /* For template nontype argument packs, also substitute into
11837 the type. */
11842 }
11857 /* We should use one of the expression tsubsts for these codes. */
11863 }
11864 }
11866 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
11867 type of the expression on the left-hand side of the "." or "->"
11868 operator. */
11870 static tree
11873 {
11874 tree name;
11875 tree qualifying_scope;
11876 tree fns;
11877 tree optype;
11882 /* A baselink indicates a function from a base class. Both the
11883 BASELINK_ACCESS_BINFO and the base class referenced may
11884 indicate bases of the template class, rather than the
11885 instantiated class. In addition, lookups that were not
11886 ambiguous before may be ambiguous now. Therefore, we perform
11887 the lookup again. */
11894 {
11901 }
11909 /* If lookup found a single function, mark it as used at this
11910 point. (If it lookup found multiple functions the one selected
11911 later by overload resolution will be marked as used at that
11912 point.) */
11918 /* Add back the template arguments, if present. */
11923 template_args);
11924 /* Update the conversion operator type. */
11932 qualifying_scope,
11933 object_type);
11935 }
11937 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
11938 true if the qualified-id will be a postfix-expression in-and-of
11939 itself; false if more of the postfix-expression follows the
11940 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
11941 of "&". */
11943 static tree
11947 {
11948 tree expr;
11949 tree scope;
11950 tree name;
11952 tree template_args;
11957 /* Figure out what name to look up. */
11960 {
11968 }
11969 else
11970 {
11973 }
11975 /* Substitute into the qualifying scope. When there are no ARGS, we
11976 are just trying to simplify a non-dependent expression. In that
11977 case the qualifying scope may be dependent, and, in any case,
11978 substituting will not help. */
11981 {
11984 }
11985 else
11989 {
11994 }
11997 {
11999 {
12000 /* A BIT_NOT_EXPR is used to represent a destructor. */
12002 {
12006 }
12007 else
12010 }
12011 else
12015 {
12017 {
12021 }
12023 }
12024 }
12027 {
12029 scope);
12030 /* Remember that there was a reference to this entity. */
12032 }
12035 {
12041 }
12050 {
12051 expr = (adjust_result_of_qualified_name_lookup
12053 expr = (finish_qualified_id_expr
12057 }
12059 /* Expressions do not generally have reference type. */
12061 /* However, if we're about to form a pointer-to-member, we just
12062 want the referenced member referenced. */
12067 }
12069 /* Like tsubst, but deals with expressions. This function just replaces
12070 template parms; to finish processing the resultant expression, use
12071 tsubst_copy_and_build or tsubst_expr. */
12073 static tree
12075 {
12077 tree r;
12085 {
12090 {
12091 /* We get here for a use of 'this' in an NSDMI. */
12097 /* This can happen for a parameter name used later in a function
12098 declaration (such as in a late-specified return type). Just
12099 make a dummy decl, since it's only used for its type. */
12102 /* Give it the template pattern as its context; its true context
12103 hasn't been instantiated yet and this is good enough for
12104 mangling. */
12106 }
12114 {
12115 tree enum_type;
12116 tree v;
12120 /* There is no need to substitute into namespace-scope
12121 enumerators. */
12124 /* If ARGS is NULL, then T is known to be non-dependent. */
12128 /* Unfortunately, we cannot just call lookup_name here.
12129 Consider:
12131 template <int I> int f() {
12132 enum E { a = I };
12133 struct S { void g() { E e = a; } };
12134 };
12136 When we instantiate f<7>::S::g(), say, lookup_name is not
12137 clever enough to find f<7>::a. */
12138 enum_type
12148 /* We didn't find the name. That should never happen; if
12149 name-lookup found it during preliminary parsing, we
12150 should find it again here during instantiation. */
12152 }
12157 {
12158 tree ctx;
12163 {
12166 {
12170 }
12172 }
12173 }
12189 /* An OVERLOAD will always be a non-dependent overload set; an
12190 overload set from function scope will just be represented with an
12191 IDENTIFIER_NODE, and from class scope with a BASELINK. */
12206 {
12207 /* Template template argument like the following example need
12208 special treatment:
12210 template <template <class> class TT> struct C {};
12211 template <class T> struct D {
12212 template <class U> struct E {};
12213 C<E> c; // #1
12214 };
12215 D<int> d; // #2
12217 We are processing the template argument `E' in #1 for
12218 the template instantiation #2. Originally, `E' is a
12219 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
12220 have to substitute this with one having context `D<int>'. */
12224 }
12225 else
12226 /* Ordinary template template argument. */
12237 return build1
12243 {
12253 /* We only want to compute the number of arguments. */
12267 {
12274 else
12277 }
12278 else
12280 }
12282 {
12290 }
12291 /* Fall through */
12306 return build1
12311 {
12312 tree object;
12313 tree name;
12318 {
12322 }
12325 {
12335 }
12340 in_decl);
12341 else
12344 }
12382 return build_nt
12395 return build_nt
12402 {
12410 }
12415 {
12416 r = build_nt
12422 }
12425 {
12426 r = build_nt
12432 }
12435 {
12436 r = build_nt
12442 }
12445 {
12446 /* Substituted template arguments */
12455 }
12458 {
12478 }
12503 {
12506 }
12507 else
12511 /* This is handled by tsubst_copy_and_build. */
12517 in_decl),
12521 /* We shouldn't have built any of these during initial template
12522 generation. Instead, they should be built during instantiation
12523 in response to the saved STMT_IS_FULL_EXPR_P setting. */
12527 r = build2
12547 {
12548 /* Instantiate any typedefs in the type. */
12553 }
12556 /* These can sometimes show up in a partial instantiation, but never
12557 involve template parms. */
12562 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
12565 }
12566 }
12568 /* Like tsubst_copy, but specifically for OpenMP clauses. */
12570 static tree
12572 tree in_decl)
12573 {
12577 {
12583 {
12586 {
12592 }
12593 /* FALLTHRU */
12617 }
12618 }
12621 }
12623 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
12625 static tree
12627 tree in_decl)
12628 {
12629 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
12649 {
12652 else
12653 {
12657 }
12658 }
12663 #undef RECUR
12664 }
12666 /* Substitute one OMP_FOR iterator. */
12668 static void
12673 {
12674 #define RECUR(NODE) \
12675 tsubst_expr ((NODE), args, complain, in_decl, \
12676 integral_constant_expression_p)
12684 /* Do this before substituting into decl to handle 'auto'. */
12689 {
12693 }
12698 {
12705 complain);
12706 else
12713 }
12716 {
12717 tree c;
12719 {
12730 }
12732 {
12737 {
12740 }
12741 }
12742 }
12748 else
12752 {
12763 {
12770 }
12771 else
12777 {
12783 }
12787 {
12794 }
12795 else
12801 }
12807 #undef RECUR
12808 }
12810 /* Like tsubst_copy for expressions, etc. but also does semantic
12811 processing. */
12813 static tree
12816 {
12817 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12818 #define RECUR(NODE) \
12819 tsubst_expr ((NODE), args, complain, in_decl, \
12820 integral_constant_expression_p)
12823 tree r;
12824 location_t loc;
12836 {
12838 {
12839 tree_stmt_iterator i;
12843 }
12858 else
12867 {
12869 tree init;
12875 {
12878 tree decl;
12886 else
12888 }
12889 else
12890 {
12894 {
12895 /* By marking the declaration as instantiated, we avoid
12896 trying to instantiate it. Since instantiate_decl can't
12897 handle local variables, and since we've already done
12898 all that needs to be done, that's the right thing to
12899 do. */
12904 /* Anonymous aggregates are a special case. */
12907 {
12910 {
12914 }
12916 }
12919 else
12920 {
12925 {
12926 /* For __PRETTY_FUNCTION__ we have to adjust the
12927 initializer. */
12931 }
12932 else
12933 {
12937 {
12938 /* If we had an initializer but it
12939 instantiated to nothing,
12940 value-initialize the object. This will
12941 only occur when the initializer was a
12942 pack expansion where the parameter packs
12943 used in that expansion were of length
12944 zero. */
12946 complain);
12949 }
12950 else
12952 }
12955 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
12958 }
12959 }
12960 }
12963 }
12978 {
12988 }
13015 {
13019 }
13027 else
13035 else
13062 {
13064 tree label;
13069 }
13075 /* Computed goto's must be tsubst'd into. On the other hand,
13076 non-computed gotos must not be; the identifier in question
13077 will have no binding. */
13079 else
13085 tmp = finish_asm_stmt
13092 {
13097 }
13102 {
13107 }
13108 else
13109 {
13114 else
13121 else
13127 else
13129 }
13133 {
13137 {
13139 /* Prevent instantiate_decl from trying to instantiate
13140 this variable. We've already done all that needs to be
13141 done. */
13144 }
13149 }
13155 {
13156 /* Local classes are not independent templates; they are
13157 instantiated along with their containing function. And this
13158 way we don't have to deal with pushing out of one local class
13159 to instantiate a member of another local class. */
13160 tree fn;
13161 /* Closures are handled by the LAMBDA_EXPR. */
13167 }
13171 {
13172 tree condition;
13175 condition =
13177 args,
13186 }
13207 {
13224 integral_constant_expression_p);
13238 }
13270 {
13275 {
13278 }
13283 }
13284 else
13285 {
13292 {
13295 }
13298 {
13303 {
13306 }
13310 }
13311 else
13312 {
13316 }
13318 }
13322 {
13328 {
13332 {
13337 }
13341 }
13342 else
13343 {
13348 }
13349 }
13367 /* If the first operand was a statement, we're done with it. */
13371 complain));
13378 integral_constant_expression_p));
13379 }
13382 out:
13385 #undef RECUR
13386 #undef RETURN
13387 }
13389 /* T is a postfix-expression that is not being used in a function
13390 call. Return the substituted version of T. */
13392 static tree
13394 tsubst_flags_t complain,
13395 tree in_decl)
13396 {
13400 else
13406 }
13408 /* Like tsubst but deals with expressions and performs semantic
13409 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
13411 tree
13413 tree args,
13414 tsubst_flags_t complain,
13415 tree in_decl,
13418 {
13419 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
13420 #define RECUR(NODE) \
13421 tsubst_copy_and_build (NODE, args, complain, in_decl, \
13423 integral_constant_expression_p)
13426 location_t loc;
13435 /* N3276 decltype magic only applies to calls at the top level or on the
13436 right side of a comma. */
13442 {
13445 /* Fall through. */
13447 {
13448 tree decl;
13449 cp_id_kind idk;
13454 {
13457 }
13459 /* Look up the name. */
13462 /* By convention, expressions use ERROR_MARK_NODE to indicate
13463 failure, not NULL_TREE. */
13469 integral_constant_expression_p,
13477 input_location);
13481 {
13485 }
13487 }
13490 {
13491 tree object;
13499 {
13502 }
13503 else
13510 else
13512 }
13515 {
13519 {
13520 /* A type conversion to reference type will be enclosed in
13521 such an indirect ref, but the substitution of the cast
13522 will have also added such an indirect ref. */
13525 }
13526 else
13529 }
13537 {
13544 flags));
13545 }
13558 {
13559 tree type;
13565 {
13570 }
13576 {
13594 }
13598 }
13630 else
13632 in_decl);
13666 {
13667 tree r;
13671 r = build_x_binary_op
13675 ? ERROR_MARK
13679 ? ERROR_MARK
13682 complain);
13689 }
13703 /* Fall through */
13706 {
13707 tree r;
13713 {
13714 /* When there are no ARGS, we are trying to evaluate a
13715 non-dependent expression from the parser. Trying to do
13716 the substitutions may not work. */
13719 }
13720 else
13721 {
13726 else
13729 /*integral_constant_expression_p=*/
13733 }
13737 else
13741 {
13743 {
13745 {
13749 }
13750 else
13754 }
13756 }
13758 }
13761 {
13771 }
13785 {
13786 tree r = build_x_modify_expr
13791 complain);
13792 /* TREE_NO_WARNING must be set if either the expression was
13793 parenthesized or it uses an operator such as >>= rather
13794 than plain assignment. In the former case, it was already
13795 set and must be copied. In the latter case,
13796 build_x_modify_expr sets it and it must not be reset
13797 here. */
13801 }
13806 /* Remember that there was a reference to this entity. */
13812 {
13817 tree ret;
13821 else
13822 {
13826 }
13828 /* If there was an initializer in the original tree, but it
13829 instantiated to an empty list, then we should pass a
13830 non-NULL empty vector to tell build_new that it was an
13831 empty initializer() rather than no initializer. This can
13832 only happen when the initializer is a pack expansion whose
13833 parameter packs are of length zero. */
13836 else
13837 {
13841 else
13842 {
13845 }
13846 }
13853 complain);
13861 }
13869 complain));
13872 {
13876 integral_constant_expression_p);
13878 op0,
13880 complain));
13881 }
13884 {
13885 tree function;
13890 tree ret;
13892 /* Don't pass tf_decltype down to subexpressions. */
13897 /* When we parsed the expression, we determined whether or
13898 not Koenig lookup should be performed. */
13901 {
13906 }
13908 {
13909 /* Do nothing; calling tsubst_copy_and_build on an identifier
13910 would incorrectly perform unqualified lookup again.
13912 Note that we can also have an IDENTIFIER_NODE if the earlier
13913 unqualified lookup found a member function; in that case
13914 koenig_p will be false and we do want to do the lookup
13915 again to find the instantiated member function.
13917 FIXME but doing that causes c++/15272, so we need to stop
13918 using IDENTIFIER_NODE in that situation. */
13920 }
13921 else
13922 {
13924 {
13930 }
13931 else
13936 /* Avoid error about taking the address of a constructor. */
13940 in_decl,
13942 integral_constant_expression_p);
13946 }
13951 {
13956 else
13957 {
13958 /* Expand the pack expansion and push each entry onto
13959 CALL_ARGS. */
13962 {
13967 {
13972 }
13973 }
13974 else
13975 {
13976 /* A partial substitution. Add one entry. */
13978 }
13979 }
13980 }
13982 /* We do not perform argument-dependent lookup if normal
13983 lookup finds a non-function, in accordance with the
13984 expected resolution of DR 218. */
13987 /* If lookup found a member function, the Koenig lookup is
13988 not appropriate, even if an unqualified-name was used
13989 to denote the function. */
13992 /* Only do this when substitution turns a dependent call
13993 into a non-dependent call. */
13997 tf_none);
14001 {
14003 {
14004 /* For backwards compatibility and good diagnostics, try
14005 the unqualified lookup again if we aren't in SFINAE
14006 context. */
14007 tree unq = (tsubst_copy_and_build
14009 integral_constant_expression_p));
14014 {
14023 "%qD was not declared in this scope, "
14024 "and no declarations were found by "
14025 "argument-dependent lookup at the point "
14027 {
14031 {
14033 "declarations in dependent base %qT are "
14039 else
14043 }
14044 else
14047 }
14049 }
14050 }
14052 {
14057 }
14058 }
14060 /* Remember that there was a reference to this entity. */
14064 /* Put back tf_decltype for the actual call. */
14069 complain);
14071 {
14086 complain);
14087 else
14088 ret = (build_new_method_call
14093 complain));
14094 }
14095 else
14098 koenig_p,
14099 complain);
14104 }
14107 {
14112 {
14114 {
14119 }
14120 else
14121 {
14126 }
14127 }
14128 else
14129 {
14132 }
14136 }
14145 {
14153 {
14154 /* We have pack expansions, so expand those and
14155 create a new list out of it. */
14158 tree chain;
14161 /* Expand the argument expressions. */
14169 /* Build the rest of the list. */
14174 /* Determine the number of arguments. */
14176 {
14179 }
14182 else
14183 {
14184 /* Since we only performed a partial substitution into
14185 the argument pack, we only RETURN (a single list
14186 node. */
14193 }
14195 /* Convert the argument vectors into a TREE_LIST */
14198 {
14199 /* Grab the Ith values. */
14200 i--;
14203 value
14207 /* Build the list (backwards). */
14209 }
14212 }
14228 }
14231 {
14232 tree object;
14233 tree object_type;
14234 tree member;
14238 /* Remember that there was a reference to this entity. */
14248 else
14256 {
14258 {
14263 {
14266 }
14268 {
14272 }
14273 }
14274 }
14277 {
14278 /* Lookup the template functions now that we know what the
14279 scope is. */
14287 {
14290 args);
14291 member = (adjust_result_of_qualified_name_lookup
14293 object_type));
14294 }
14295 else
14296 {
14298 input_location);
14300 }
14301 }
14305 {
14307 {
14311 else
14314 }
14316 }
14322 complain));
14323 }
14330 {
14338 tree r;
14343 /* digest_init will do the wrong thing if we let it. */
14347 /* We do not want to process the index of aggregate
14348 initializers as they are identifier nodes which will be
14349 looked up by digest_init. */
14355 {
14360 {
14361 /* Substitute into the pack expansion. */
14363 in_decl);
14367 ;
14369 /* Just move the argument into place. */
14371 else
14372 {
14373 /* Update the length of the final CONSTRUCTOR
14374 arguments vector, and note that we will need to
14375 copy.*/
14378 }
14379 }
14380 else
14382 }
14385 {
14390 {
14392 {
14397 }
14398 else
14400 }
14401 }
14411 }
14414 {
14417 {
14420 }
14421 else
14422 {
14425 }
14426 }
14431 /* Fall through */
14434 {
14438 /* If the original type was a reference, we'll be wrapped in
14439 the appropriate INDIRECT_REF. */
14442 }
14453 {
14462 }
14465 {
14471 integral_constant_expression_p);
14475 /* If the resulting list of expression statement is empty,
14476 fold it further into void_zero_node. */
14481 }
14484 {
14498 /* For a function scope, we want to use tsubst so that we don't
14499 complain about referring to an auto function before its return
14500 type has been deduced. Otherwise, we want to use tsubst_copy so
14501 that we look up the existing field/parameter/variable rather
14502 than build a new one. */
14507 {
14508 /* Look up the parameter we want directly, as tsubst_copy
14509 doesn't do what we need. */
14515 /* FIXME Work around the parm not having DECL_CONTEXT set. */
14518 }
14519 else
14528 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
14530 /* Now that we know visibility, instantiate the type so we have a
14531 declaration of the op() for later calls to lambda_function. */
14537 }
14540 /* We can get here for a constant initializer of non-dependent type.
14541 FIXME stop folding in cp_parser_initializer_clause. */
14542 {
14544 complain);
14546 }
14550 integral_constant_expression_p));
14553 /* Handle Objective-C++ constructs, if appropriate. */
14554 {
14555 tree subst
14560 }
14562 }
14564 #undef RECUR
14565 #undef RETURN
14566 out:
14569 }
14571 /* Verify that the instantiated ARGS are valid. For type arguments,
14572 make sure that the type's linkage is ok. For non-type arguments,
14573 make sure they are constants if they are integral or enumerations.
14574 Emit an error under control of COMPLAIN, and return TRUE on error. */
14576 static bool
14578 {
14582 {
14592 }
14594 {
14595 /* [basic.link]: A name with no linkage (notably, the name
14596 of a class or enumeration declared in a local scope)
14597 shall not be used to declare an entity with linkage.
14598 This implies that names with no linkage cannot be used as
14599 template arguments
14601 DR 757 relaxes this restriction for C++0x. */
14606 {
14607 /* DR 488 makes use of a type with no linkage cause
14608 type deduction to fail. */
14610 {
14613 else
14616 }
14618 }
14619 /* In order to avoid all sorts of complications, we do not
14620 allow variably-modified types as template arguments. */
14622 {
14626 }
14627 }
14628 /* Class template and alias template arguments should be OK. */
14630 ;
14631 /* A non-type argument of integral or enumerated type must be a
14632 constant. */
14636 {
14640 }
14642 }
14644 static bool
14646 {
14651 {
14654 }
14658 }
14660 /* We're out of SFINAE context now, so generate diagnostics for the access
14661 errors we saw earlier when instantiating D from TMPL and ARGS. */
14663 static void
14665 {
14677 }
14679 /* Instantiate the indicated variable, function, or alias template TMPL with
14680 the template arguments in TARG_PTR. */
14682 static tree
14684 {
14686 tree fndecl;
14687 tree gen_tmpl;
14688 tree spec;
14696 /* If this function is a clone, handle it specially. */
14698 {
14699 tree spec;
14700 tree clone;
14702 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
14703 DECL_CLONED_FUNCTION. */
14709 /* Look for the clone. */
14713 /* We should always have found the clone by now. */
14716 }
14718 /* Check to see if we already have this specialization. */
14721 /* The TMPL is a partial instantiation. To get a full set of
14722 arguments we must add the arguments used to perform the
14723 partial instantiation. */
14725 targ_ptr);
14727 /* It would be nice to avoid hashing here and then again in tsubst_decl,
14728 but it doesn't seem to be on the hot path. */
14737 {
14739 {
14743 }
14745 }
14748 complain))
14751 /* We are building a FUNCTION_DECL, during which the access of its
14752 parameters and return types have to be checked. However this
14753 FUNCTION_DECL which is the desired context for access checking
14754 is not built yet. We solve this chicken-and-egg problem by
14755 deferring all checks until we have the FUNCTION_DECL. */
14758 /* Instantiation of the function happens in the context of the function
14759 template, not the context of the overload resolution we're doing. */
14761 /* If there are dependent arguments, e.g. because we're doing partial
14762 ordering, make sure processing_template_decl stays set. */
14766 {
14770 }
14771 /* Substitute template parameters to obtain the specialization. */
14779 {
14782 }
14784 /* The DECL_TI_TEMPLATE should always be the immediate parent
14785 template, not the most general template. */
14788 /* Now we know the specialization, compute access previously
14789 deferred. */
14796 /* If we've just instantiated the main entry point for a function,
14797 instantiate all the alternate entry points as well. We do this
14798 by cloning the instantiation of the main entry point, not by
14799 instantiating the template clones. */
14804 {
14806 {
14807 /* Remember to reinstantiate when we're out of SFINAE so the user
14808 can see the errors. */
14810 }
14812 }
14814 }
14816 /* Wrapper for instantiate_template_1. */
14818 tree
14820 {
14821 tree ret;
14826 }
14828 /* Instantiate the alias template TMPL with ARGS. Also push a template
14829 instantiation level, which instantiate_template doesn't do because
14830 functions and variables have sufficient context established by the
14831 callers. */
14833 static tree
14835 {
14842 {
14845 }
14847 args =
14855 /* We can't free this if a pending_template entry or last_error_tinst_level
14856 is pointing at it. */
14862 }
14864 /* PARM is a template parameter pack for FN. Returns true iff
14865 PARM is used in a deducible way in the argument list of FN. */
14867 static bool
14869 {
14872 {
14874 tree packs;
14880 {
14881 /* The template parameter pack is used in a function parameter
14882 pack. If this is the end of the parameter list, the
14883 template parameter pack is deducible. */
14886 else
14887 /* Otherwise, not. Well, it could be deduced from
14888 a non-pack parameter, but doing so would end up with
14889 a deduction mismatch, so don't bother. */
14891 }
14892 }
14893 /* The template parameter pack isn't used in any function parameter
14894 packs, but it might be used deeper, e.g. tuple<Args...>. */
14896 }
14898 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
14899 NARGS elements of the arguments that are being used when calling
14900 it. TARGS is a vector into which the deduced template arguments
14901 are placed.
14903 Return zero for success, 2 for an incomplete match that doesn't resolve
14904 all the types, and 1 for complete failure. An error message will be
14905 printed only for an incomplete match.
14907 If FN is a conversion operator, or we are trying to produce a specific
14908 specialization, RETURN_TYPE is the return type desired.
14910 The EXPLICIT_TARGS are explicit template arguments provided via a
14911 template-id.
14913 The parameter STRICT is one of:
14915 DEDUCE_CALL:
14916 We are deducing arguments for a function call, as in
14917 [temp.deduct.call].
14919 DEDUCE_CONV:
14920 We are deducing arguments for a conversion function, as in
14921 [temp.deduct.conv].
14923 DEDUCE_EXACT:
14924 We are deducing arguments when doing an explicit instantiation
14925 as in [temp.explicit], when determining an explicit specialization
14926 as in [temp.expl.spec], or when taking the address of a function
14927 template, as in [temp.deduct.funcaddr]. */
14929 tree
14931 tree explicit_targs,
14932 tree targs,
14935 tree return_type,
14936 unification_kind_t strict,
14940 {
14941 tree parms;
14942 tree fntype;
14950 tree tinst;
14956 /* In C++0x, it's possible to have a function template whose type depends
14957 on itself recursively. This is most obvious with decltype, but can also
14958 occur with enumeration scope (c++/48969). So we need to catch infinite
14959 recursion and reject the substitution at deduction time; this function
14960 will return error_mark_node for any repeated substitution.
14962 This also catches excessive recursion such as when f<N> depends on
14963 f<N-1> across all integers, and returns error_mark_node for all the
14964 substitutions back up to the initial one.
14966 This is, of course, not reentrant. */
14977 {
14978 /* [temp.deduct]
14980 The specified template arguments must match the template
14981 parameters in kind (i.e., type, nontype, template), and there
14982 must not be more arguments than there are parameters;
14983 otherwise type deduction fails.
14985 Nontype arguments must match the types of the corresponding
14986 nontype template parameters, or must be convertible to the
14987 types of the corresponding nontype parameters as specified in
14988 _temp.arg.nontype_, otherwise type deduction fails.
14990 All references in the function type of the function template
14991 to the corresponding template parameters are replaced by the
14992 specified template argument values. If a substitution in a
14993 template parameter or in the function type of the function
14994 template results in an invalid type, type deduction fails. */
14999 /* Adjust any explicit template arguments before entering the
15000 substitution context. */
15001 explicit_targs
15003 complain,
15009 /* Substitute the explicit args into the function type. This is
15010 necessary so that, for instance, explicitly declared function
15011 arguments can match null pointed constants. If we were given
15012 an incomplete set of explicit args, we must not do semantic
15013 processing during substitution as we could create partial
15014 instantiations. */
15016 {
15021 /* Dig out the actual parm. */
15024 {
15027 }
15029 {
15032 }
15035 /* No explicit argument for this template parameter. */
15039 {
15040 /* Mark the argument pack as "incomplete". We could
15041 still deduce more arguments during unification.
15042 We remove this mark in type_unification_real. */
15044 {
15048 }
15050 /* We have some incomplete argument packs. */
15052 }
15053 }
15057 {
15060 }
15072 /* Throw away these access checks; we'll see them again in
15073 instantiate_template and they might have the wrong
15074 access path at this point. */
15078 /* Place the explicitly specified arguments in TARGS. */
15081 }
15083 /* Never do unification on the 'this' parameter. */
15087 {
15096 }
15098 /* We allow incomplete unification without an error message here
15099 because the standard doesn't seem to explicitly prohibit it. Our
15100 callers must be ready to deal with unification failures in any
15101 event. */
15109 /* Now that we have bindings for all of the template arguments,
15110 ensure that the arguments deduced for the template template
15111 parameters have compatible template parameter lists. We cannot
15112 check this property before we have deduced all template
15113 arguments, because the template parameter types of a template
15114 template parameter might depend on prior template parameters
15115 deduced after the template template parameter. The following
15116 ill-formed example illustrates this issue:
15118 template<typename T, template<T> class C> void f(C<5>, T);
15120 template<int N> struct X {};
15122 void g() {
15123 f(X<5>(), 5l); // error: template argument deduction fails
15124 }
15126 The template parameter list of 'C' depends on the template type
15127 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
15128 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
15129 time that we deduce 'C'. */
15132 {
15135 }
15137 /* All is well so far. Now, check:
15139 [temp.deduct]
15141 When all template arguments have been deduced, all uses of
15142 template parameters in nondeduced contexts are replaced with
15143 the corresponding deduced argument values. If the
15144 substitution results in an invalid type, as described above,
15145 type deduction fails. */
15148 {
15151 }
15158 /* Now perform any access checks encountered during deduction, such as
15159 for default template arguments. */
15166 /* If we're looking for an exact match, check that what we got
15167 is indeed an exact match. It might not be if some template
15168 parameters are used in non-deduced contexts. */
15170 {
15174 tree sarg
15180 {
15184 }
15185 }
15189 fail:
15193 {
15195 /* Reset once we're all the way out. */
15197 }
15199 /* We can't free this if a pending_template entry or last_error_tinst_level
15200 is pointing at it. */
15206 }
15208 /* Adjust types before performing type deduction, as described in
15209 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
15210 sections are symmetric. PARM is the type of a function parameter
15211 or the return type of the conversion function. ARG is the type of
15212 the argument passed to the call, or the type of the value
15213 initialized with the result of the conversion function.
15214 ARG_EXPR is the original argument expression, which may be null. */
15216 static int
15220 tree arg_expr)
15221 {
15225 {
15230 {
15231 /* Swap PARM and ARG throughout the remainder of this
15232 function; the handling is precisely symmetric since PARM
15233 will initialize ARG rather than vice versa. */
15238 }
15241 /* Core issue #873: Do the DR606 thing (see below) for these cases,
15242 too, but here handle it by stripping the reference from PARM
15243 rather than by adding it to ARG. */
15251 /* Nothing else to do in this case. */
15256 }
15259 {
15260 /* [temp.deduct.call]
15262 If P is not a reference type:
15264 --If A is an array type, the pointer type produced by the
15265 array-to-pointer standard conversion (_conv.array_) is
15266 used in place of A for type deduction; otherwise,
15268 --If A is a function type, the pointer type produced by
15269 the function-to-pointer standard conversion
15270 (_conv.func_) is used in place of A for type deduction;
15271 otherwise,
15273 --If A is a cv-qualified type, the top level
15274 cv-qualifiers of A's type are ignored for type
15275 deduction. */
15280 else
15282 }
15284 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
15285 of the form T&&, where T is a template parameter, and the argument
15286 is an lvalue, T is deduced as A& */
15292 /* try_one_overload doesn't provide an arg_expr, but
15293 functions are always lvalues. */
15297 /* [temp.deduct.call]
15299 If P is a cv-qualified type, the top level cv-qualifiers
15300 of P's type are ignored for type deduction. If P is a
15301 reference type, the type referred to by P is used for
15302 type deduction. */
15305 {
15308 }
15310 /* DR 322. For conversion deduction, remove a reference type on parm
15311 too (which has been swapped into ARG). */
15316 }
15318 /* Subroutine of unify_one_argument. PARM is a function parameter of a
15319 template which does contain any deducible template parameters; check if
15320 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
15321 unify_one_argument. */
15323 static int
15326 {
15327 tree type;
15331 else
15338 {
15342 }
15344 {
15349 }
15353 else
15355 }
15357 /* Subroutine of type_unification_real and unify_pack_expansion to
15358 handle unification of a single P/A pair. Parameters are as
15359 for those functions. */
15361 static int
15365 {
15372 /* We can't deduce anything from this, but we might get all the
15373 template args from other function args. */
15376 /* FIXME uses_deducible_template_parms */
15379 explain_p);
15382 {
15384 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
15385 | UNIFY_ALLOW_MORE_CV_QUAL
15399 }
15401 /* We only do these transformations if this is the top-level
15402 parameter_type_list in a call or declaration matching; in other
15403 situations (nested function declarators, template argument lists) we
15404 won't be comparing a type to an expression, and we don't do any type
15405 adjustments. */
15407 {
15409 {
15412 {
15413 /* [temp.deduct.type] A template-argument can be
15414 deduced from a pointer to function or pointer
15415 to member function argument if the set of
15416 overloaded functions does not contain function
15417 templates and at most one of a set of
15418 overloaded functions provides a unique
15419 match. */
15426 }
15432 }
15434 arg_strict |=
15436 }
15437 else
15441 /* For deduction from an init-list we need the actual list. */
15445 }
15447 /* Most parms like fn_type_unification.
15449 If SUBR is 1, we're being called recursively (to unify the
15450 arguments of a function or method parameter of a function
15451 template). */
15453 static int
15455 tree targs,
15456 tree xparms,
15460 unification_kind_t strict,
15463 {
15468 tree parms;
15477 /* Reset the number of non-defaulted template arguments contained
15478 in TARGS. */
15481 again:
15489 {
15494 /* For a function parameter pack that occurs at the end of the
15495 parameter-declaration-list, the type A of each remaining
15496 argument of the call is compared with the type P of the
15497 declarator-id of the function parameter pack. */
15503 /* For a function parameter pack that does not occur at the
15504 end of the parameter-declaration-list, the type of the
15505 parameter pack is a non-deduced context. */
15514 }
15519 {
15520 /* Unify the remaining arguments with the pack expansion type. */
15521 tree argvec;
15524 /* Allocate a TREE_VEC and copy in all of the arguments */
15529 /* Copy the parameter into parmvec. */
15535 /* Advance to the end of the list of parameters. */
15537 }
15539 /* Fail if we've reached the end of the parm list, and more args
15540 are present, and the parm list isn't variadic. */
15543 /* Fail if parms are left and they don't have default values. */
15546 {
15550 {
15551 count++;
15553 }
15555 }
15558 {
15559 tsubst_flags_t complain = (explain_p
15560 ? tf_warning_or_error
15564 {
15568 /* Clear the "incomplete" flags on all argument packs now so that
15569 substituting them into later default arguments works. */
15571 {
15574 }
15580 /* If this is an undeduced nontype parameter that depends on
15581 a type parameter, try another pass; its type may have been
15582 deduced from a later argument than the one from which
15583 this parameter can be deduced. */
15589 /* Core issue #226 (C++0x) [temp.deduct]:
15591 If a template argument has not been deduced, its
15592 default template argument, if any, is used.
15594 When we are in C++98 mode, TREE_PURPOSE will either
15595 be NULL_TREE or ERROR_MARK_NODE, so we do not need
15596 to explicitly check cxx_dialect here. */
15598 {
15610 else
15611 {
15613 /* The position of the first default template argument,
15614 is also the number of non-defaulted arguments in TARGS.
15615 Record that. */
15619 }
15620 }
15622 /* If the type parameter is a parameter pack, then it will
15623 be deduced to an empty parameter pack. */
15625 {
15626 tree arg;
15629 {
15633 }
15634 else
15641 }
15644 }
15645 }
15646 #ifdef ENABLE_CHECKING
15649 #endif
15652 }
15654 /* Subroutine of type_unification_real. Args are like the variables
15655 at the call site. ARG is an overloaded function (or template-id);
15656 we try deducing template args from each of the overloads, and if
15657 only one succeeds, we go with that. Modifies TARGS and returns
15658 true on success. */
15660 static bool
15662 tree targs,
15663 tree parm,
15664 tree arg,
15665 unification_kind_t strict,
15668 {
15675 {
15678 }
15679 else
15683 /* Handle `&x' where `x' is some static or non-static member
15684 function name. */
15690 /* Strip baselink information. */
15695 {
15696 /* If we got some explicit template args, we need to plug them into
15697 the affected templates before we try to unify, in case the
15698 explicit args will completely resolve the templates in question. */
15705 {
15718 {
15723 {
15726 }
15727 }
15730 }
15731 /* If no templates (or more than one) are fully resolved by the
15732 explicit arguments, this template-id is a non-deduced context; it
15733 could still be OK if we deduce all template arguments for the
15734 enclosing call through other arguments. */
15737 }
15740 /* If ARG is, for example, "(0, &f)" then its type will be unknown
15741 -- but the deduction does not succeed because the expression is
15742 not just the function on its own. */
15744 else
15750 {
15753 }
15755 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15756 to function or pointer to member function argument if the set of
15757 overloaded functions does not contain function templates and at most
15758 one of a set of overloaded functions provides a unique match.
15760 So if we found multiple possibilities, we return success but don't
15761 deduce anything. */
15764 {
15769 }
15774 }
15776 /* Core DR 115: In contexts where deduction is done and fails, or in
15777 contexts where deduction is not done, if a template argument list is
15778 specified and it, along with any default template arguments, identifies
15779 a single function template specialization, then the template-id is an
15780 lvalue for the function template specialization. */
15782 tree
15784 {
15797 {
15800 }
15802 {
15805 }
15807 {
15810 }
15813 {
15817 /* If we got some explicit template args, we need to plug them into
15818 the affected templates before we try to unify, in case the
15819 explicit args will completely resolve the templates in question. */
15827 {
15840 {
15843 {
15846 }
15848 {
15851 }
15852 }
15853 }
15855 {
15863 {
15864 tree base
15867 }
15871 }
15873 /* There were no good options and at least one bad one, so let the
15874 user know what the problem is. */
15876 }
15878 }
15880 /* Subroutine of resolve_overloaded_unification; does deduction for a single
15881 overload. Fills TARGS with any deduced arguments, or error_mark_node if
15882 different overloads deduce different arguments for a given parm.
15883 ADDR_P is true if the expression for which deduction is being
15884 performed was of the form "& fn" rather than simply "fn".
15886 Returns 1 on success. */
15888 static int
15890 tree orig_targs,
15891 tree targs,
15892 tree parm,
15893 tree arg,
15894 unification_kind_t strict,
15898 {
15900 tree tempargs;
15906 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15907 to function or pointer to member function argument if the set of
15908 overloaded functions does not contain function templates and at most
15909 one of a set of overloaded functions provides a unique match.
15911 So if this is a template, just return success. */
15923 /* We don't copy orig_targs for this because if we have already deduced
15924 some template args from previous args, unify would complain when we
15925 try to deduce a template parameter for the same argument, even though
15926 there isn't really a conflict. */
15933 /* First make sure we didn't deduce anything that conflicts with
15934 explicitly specified args. */
15936 {
15943 /* Since we're unifying against ourselves, we will fill in
15944 template args used in the function parm list with our own
15945 template parms. Discard them. */
15949 }
15952 {
15957 }
15960 }
15962 /* PARM is a template class (perhaps with unbound template
15963 parameters). ARG is a fully instantiated type. If ARG can be
15964 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
15965 TARGS are as for unify. */
15967 static tree
15970 {
15971 tree copy_of_targs;
15978 /* We need to make a new template argument vector for the call to
15979 unify. If we used TARGS, we'd clutter it up with the result of
15980 the attempted unification, even if this class didn't work out.
15981 We also don't want to commit ourselves to all the unifications
15982 we've already done, since unification is supposed to be done on
15983 an argument-by-argument basis. In other words, consider the
15984 following pathological case:
15986 template <int I, int J, int K>
15987 struct S {};
15989 template <int I, int J>
15990 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
15992 template <int I, int J, int K>
15993 void f(S<I, J, K>, S<I, I, I>);
15995 void g() {
15996 S<0, 0, 0> s0;
15997 S<0, 1, 2> s2;
15999 f(s0, s2);
16000 }
16002 Now, by the time we consider the unification involving `s2', we
16003 already know that we must have `f<0, 0, 0>'. But, even though
16004 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
16005 because there are two ways to unify base classes of S<0, 1, 2>
16006 with S<I, I, I>. If we kept the already deduced knowledge, we
16007 would reject the possibility I=1. */
16010 /* If unification failed, we're done. */
16016 }
16018 /* Given a template type PARM and a class type ARG, find the unique
16019 base type in ARG that is an instance of PARM. We do not examine
16020 ARG itself; only its base-classes. If there is not exactly one
16021 appropriate base class, return NULL_TREE. PARM may be the type of
16022 a partial specialization, as well as a plain template type. Used
16023 by unify. */
16025 static enum template_base_result
16028 {
16030 tree binfo;
16036 {
16037 /* The type could not be completed. */
16040 }
16042 /* Walk in inheritance graph order. The search order is not
16043 important, and this avoids multiple walks of virtual bases. */
16045 {
16050 {
16051 /* If there is more than one satisfactory baseclass, then:
16053 [temp.deduct.call]
16055 If they yield more than one possible deduced A, the type
16056 deduction fails.
16058 applies. */
16060 {
16063 }
16066 }
16067 }
16071 }
16073 /* Returns the level of DECL, which declares a template parameter. */
16075 static int
16077 {
16079 {
16089 }
16091 }
16093 /* Decide whether ARG can be unified with PARM, considering only the
16094 cv-qualifiers of each type, given STRICT as documented for unify.
16095 Returns nonzero iff the unification is OK on that basis. */
16097 static int
16099 {
16105 {
16106 /* Although a CVR qualifier is ignored when being applied to a
16107 substituted template parameter ([8.3.2]/1 for example), that
16108 does not allow us to unify "const T" with "int&" because both
16109 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
16110 It is ok when we're allowing additional CV qualifiers
16111 at the outer level [14.8.2.1]/3,1st bullet. */
16121 }
16132 }
16134 /* Determines the LEVEL and INDEX for the template parameter PARM. */
16135 void
16137 {
16141 {
16144 }
16145 else
16146 {
16149 }
16150 }
16152 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
16153 do { \
16154 if (unify (TP, TA, P, A, S, EP)) \
16155 return 1; \
16156 } while (0);
16158 /* Unifies the remaining arguments in PACKED_ARGS with the pack
16159 expansion at the end of PACKED_PARMS. Returns 0 if the type
16160 deduction succeeds, 1 otherwise. STRICT is the same as in
16161 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
16162 call argument list. We'll need to adjust the arguments to make them
16163 types. SUBR tells us if this is from a recursive call to
16164 type_unification_real, or for comparing two template argument
16165 lists. */
16167 static int
16171 {
16172 tree parm
16179 /* Determine the parameter packs we will be deducing from the
16180 pattern, and record their current deductions. */
16183 {
16187 /* Determine the index and level of this parameter pack. */
16190 /* Keep track of the parameter packs and their corresponding
16191 argument packs. */
16194 }
16196 /* Loop through all of the arguments that have not yet been
16197 unified and unify each with the pattern. */
16199 {
16200 tree parm;
16204 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
16205 or the element of its argument pack at the current index if
16206 this argument was explicitly specified. */
16208 {
16217 {
16220 }
16222 }
16224 /* If we had explicit template arguments, substitute them into the
16225 pattern before deduction. */
16227 {
16228 /* Some arguments might still be unspecified or dependent. */
16236 NULL_TREE);
16241 }
16242 else
16245 /* Unify the pattern with the current argument. */
16250 /* For each parameter pack, collect the deduced value. */
16252 {
16258 }
16259 }
16261 /* Verify that the results of unification with the parameter packs
16262 produce results consistent with what we've seen before, and make
16263 the deduced argument packs available. */
16265 {
16272 /* By default keep the original deduced argument pack.
16273 If necessary, more specific code is going to update the
16274 resulting deduced argument later down in this function. */
16278 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
16279 actually deduce anything. */
16287 {
16288 /* If we had fewer function args than explicit template args,
16289 just use the explicits. */
16294 }
16297 {
16298 tree result;
16299 /* Build the deduced *_ARGUMENT_PACK. */
16301 {
16306 }
16307 else
16312 /* Note the deduced argument packs for this parameter
16313 pack. */
16315 }
16319 {
16320 /* We only had the explicitly-provided arguments before, but
16321 now we have a complete set of arguments. */
16327 }
16328 else
16329 {
16335 /* Inconsistent unification of this parameter pack. */
16337 bad_old_arg,
16338 bad_new_arg);
16339 }
16340 }
16343 }
16345 /* Deduce the value of template parameters. TPARMS is the (innermost)
16346 set of template parameters to a template. TARGS is the bindings
16347 for those template parameters, as determined thus far; TARGS may
16348 include template arguments for outer levels of template parameters
16349 as well. PARM is a parameter to a template function, or a
16350 subcomponent of that parameter; ARG is the corresponding argument.
16351 This function attempts to match PARM with ARG in a manner
16352 consistent with the existing assignments in TARGS. If more values
16353 are deduced, then TARGS is updated.
16355 Returns 0 if the type deduction succeeds, 1 otherwise. The
16356 parameter STRICT is a bitwise or of the following flags:
16358 UNIFY_ALLOW_NONE:
16359 Require an exact match between PARM and ARG.
16360 UNIFY_ALLOW_MORE_CV_QUAL:
16361 Allow the deduced ARG to be more cv-qualified (by qualification
16362 conversion) than ARG.
16363 UNIFY_ALLOW_LESS_CV_QUAL:
16364 Allow the deduced ARG to be less cv-qualified than ARG.
16365 UNIFY_ALLOW_DERIVED:
16366 Allow the deduced ARG to be a template base class of ARG,
16367 or a pointer to a template base class of the type pointed to by
16368 ARG.
16369 UNIFY_ALLOW_INTEGER:
16370 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
16371 case for more information.
16372 UNIFY_ALLOW_OUTER_LEVEL:
16373 This is the outermost level of a deduction. Used to determine validity
16374 of qualification conversions. A valid qualification conversion must
16375 have const qualified pointers leading up to the inner type which
16376 requires additional CV quals, except at the outer level, where const
16377 is not required [conv.qual]. It would be normal to set this flag in
16378 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
16379 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
16380 This is the outermost level of a deduction, and PARM can be more CV
16381 qualified at this point.
16382 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
16383 This is the outermost level of a deduction, and PARM can be less CV
16384 qualified at this point. */
16386 static int
16389 {
16391 tree targ;
16392 tree tparm;
16395 /* I don't think this will do the right thing with respect to types.
16396 But the only case I've seen it in so far has been array bounds, where
16397 signedness is the only information lost, and I think that will be
16398 okay. */
16406 /* We can't deduce anything from this, but we might get all the
16407 template args from other function args. */
16410 /* If PARM uses template parameters, then we can't bail out here,
16411 even if ARG == PARM, since we won't record unifications for the
16412 template parameters. We might need them if we're trying to
16413 figure out which of two things is more specialized. */
16417 /* Handle init lists early, so the rest of the function can assume
16418 we're dealing with a type. */
16420 {
16425 /* Replace T with std::initializer_list<T> for deduction. */
16431 /* We can only deduce from an initializer list argument if the
16432 parameter is std::initializer_list; otherwise this is a
16433 non-deduced context. */
16439 {
16446 {
16448 /* It should only be possible to get here for a call. */
16450 elt_strict |= maybe_adjust_types_for_deduction
16453 }
16456 explain_p);
16457 }
16459 /* If the std::initializer_list<T> deduction worked, replace the
16460 deduced A with std::initializer_list<A>. */
16462 {
16467 }
16469 }
16471 /* Immediately reject some pairs that won't unify because of
16472 cv-qualification mismatches. */
16475 /* It is the elements of the array which hold the cv quals of an array
16476 type, and the elements might be template type parms. We'll check
16477 when we recurse. */
16479 /* We check the cv-qualifiers when unifying with template type
16480 parameters below. We want to allow ARG `const T' to unify with
16481 PARM `T' for example, when computing which of two templates
16482 is more specialized, for example. */
16496 {
16500 /* In a type which contains a nested-name-specifier, template
16501 argument values cannot be deduced for template parameters used
16502 within the nested-name-specifier. */
16514 /* The PARM is not one we're trying to unify. Just check
16515 to see if it matches ARG. */
16516 {
16521 else
16523 }
16530 /* Check for mixed types and values. */
16538 {
16539 /* ARG must be constructed from a template class or a template
16540 template parameter. */
16545 {
16549 tree parm_parms
16550 = DECL_INNERMOST_TEMPLATE_PARMS
16555 /* The resolution to DR150 makes clear that default
16556 arguments for an N-argument may not be used to bind T
16557 to a template template parameter with fewer than N
16558 parameters. It is not safe to permit the binding of
16559 default arguments as an extension, as that may change
16560 the meaning of a conforming program. Consider:
16562 struct Dense { static const unsigned int dim = 1; };
16564 template <template <typename> class View,
16565 typename Block>
16566 void operator+(float, View<Block> const&);
16568 template <typename Block,
16569 unsigned int Dim = Block::dim>
16570 struct Lvalue_proxy { operator float() const; };
16572 void
16573 test_1d (void) {
16574 Lvalue_proxy<Dense> p;
16575 float b;
16576 b + p;
16577 }
16579 Here, if Lvalue_proxy is permitted to bind to View, then
16580 the global operator+ will be used; if they are not, the
16581 Lvalue_proxy will be converted to float. */
16583 full_argvec,
16585 (explain_p
16586 ? tf_warning_or_error
16593 /* Deduce arguments T, i from TT<T> or TT<i>.
16594 We check each element of PARMVEC and ARGVEC individually
16595 rather than the whole TREE_VEC since they can have
16596 different number of elements. */
16603 /* Check if the parameters end in a pack, making them
16604 variadic. */
16610 /* If the template argument list of P contains a pack
16611 expansion that is not the last template argument, the
16612 entire template argument list is a non-deduced
16613 context. */
16622 {
16627 }
16632 DEDUCE_EXACT,
16635 }
16638 /* Fall through to deduce template name. */
16639 }
16643 {
16644 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
16646 /* Simple cases: Value already set, does match or doesn't. */
16651 }
16652 else
16653 {
16654 /* If PARM is `const T' and ARG is only `int', we don't have
16655 a match unless we are allowing additional qualification.
16656 If ARG is `const int' and PARM is just `T' that's OK;
16657 that binds `const int' to `T'. */
16662 /* Consider the case where ARG is `const volatile int' and
16663 PARM is `const T'. Then, T should be `volatile int'. */
16664 arg = cp_build_qualified_type_real
16669 /* Simple cases: Value already set, does match or doesn't. */
16675 /* Make sure that ARG is not a variable-sized array. (Note
16676 that were talking about variable-sized arrays (like
16677 `int[n]'), rather than arrays of unknown size (like
16678 `int[]').) We'll get very confused by such a type since
16679 the bound of the array is not constant, and therefore
16680 not mangleable. Besides, such types are not allowed in
16681 ISO C++, so we can do as we please here. We do allow
16682 them for 'auto' deduction, since that isn't ABI-exposed. */
16686 /* Strip typedefs as in convert_template_argument. */
16688 }
16690 /* If ARG is a parameter pack or an expansion, we cannot unify
16691 against it unless PARM is also a parameter pack. */
16696 /* If the argument deduction results is a METHOD_TYPE,
16697 then there is a problem.
16698 METHOD_TYPE doesn't map to any real C++ type the result of
16699 the deduction can not be of that type. */
16713 {
16714 /* The PARM is not one we're trying to unify. Just check
16715 to see if it matches ARG. */
16721 }
16727 {
16732 }
16734 /* [temp.deduct.type] If, in the declaration of a function template
16735 with a non-type template-parameter, the non-type
16736 template-parameter is used in an expression in the function
16737 parameter-list and, if the corresponding template-argument is
16738 deduced, the template-argument type shall match the type of the
16739 template-parameter exactly, except that a template-argument
16740 deduced from an array bound may be of any integral type.
16741 The non-type parameter might use already deduced type parameters. */
16744 /* Template-parameter dependent expression. Just accept it for now.
16745 It will later be processed in convert_template_argument. */
16746 ;
16752 /* Convert the ARG to the type of PARM; the deduced non-type
16753 template argument must exactly match the types of the
16754 corresponding parameter. */
16757 /* We haven't deduced the type of this parameter yet. Try again
16758 later. */
16760 else
16763 /* If ARG is a parameter pack or an expansion, we cannot unify
16764 against it unless PARM is also a parameter pack. */
16774 {
16775 /* A pointer-to-member constant can be unified only with
16776 another constant. */
16780 /* Just unify the class member. It would be useless (and possibly
16781 wrong, depending on the strict flags) to unify also
16782 PTRMEM_CST_CLASS, because we want to be sure that both parm and
16783 arg refer to the same variable, even if through different
16784 classes. For instance:
16786 struct A { int x; };
16787 struct B : A { };
16789 Unification of &A::x and &B::x must succeed. */
16792 }
16795 {
16799 /* [temp.deduct.call]
16801 A can be another pointer or pointer to member type that can
16802 be converted to the deduced A via a qualification
16803 conversion (_conv.qual_).
16805 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
16806 This will allow for additional cv-qualification of the
16807 pointed-to types if appropriate. */
16810 /* The derived-to-base conversion only persists through one
16811 level of pointers. */
16816 }
16833 {
16834 tree parm_max;
16835 tree arg_max;
16839 /* Our representation of array types uses "N - 1" as the
16840 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
16841 not an integer constant. We cannot unify arbitrarily
16842 complex expressions, so we eliminate the MINUS_EXPRs
16843 here. */
16847 {
16850 }
16854 {
16855 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
16856 trying to unify the type of a variable with the type
16857 of a template parameter. For example:
16859 template <unsigned int N>
16860 void f (char (&) [N]);
16861 int g();
16862 void h(int i) {
16863 char a[g(i)];
16864 f(a);
16865 }
16867 Here, the type of the ARG will be "int [g(i)]", and
16868 may be a SAVE_EXPR, etc. */
16872 }
16874 /* If only one of the bounds used a MINUS_EXPR, compensate
16875 by adding one to the other bound. */
16878 integer_type_node,
16879 parm_max,
16880 integer_one_node);
16883 integer_type_node,
16884 arg_max,
16885 integer_one_node);
16889 }
16903 /* We have already checked cv-qualification at the top of the
16904 function. */
16908 /* As far as unification is concerned, this wins. Later checks
16909 will invalidate it if necessary. */
16912 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
16913 /* Type INTEGER_CST can come from ordinary constant template args. */
16925 {
16935 /* Check for pack expansions in the parameters. */
16937 {
16939 {
16941 /* We can unify against something with a trailing
16942 parameter pack. */
16944 else
16945 /* [temp.deduct.type]/9: If the template argument list of
16946 P contains a pack expansion that is not the last
16947 template argument, the entire template argument list
16948 is a non-deduced context. */
16950 }
16951 }
16953 /* If we don't have enough arguments to satisfy the parameters
16954 (not counting the pack expression at the end), or we have
16955 too many arguments for a parameter list that doesn't end in
16956 a pack expression, we can't unify. */
16962 /* Unify all of the parameters that precede the (optional)
16963 pack expression. */
16965 {
16970 }
16973 DEDUCE_EXACT,
16976 }
16984 {
16992 }
16995 {
16999 {
17000 /* First, we try to unify the PARM and ARG directly. */
17005 {
17006 /* Fallback to the special case allowed in
17007 [temp.deduct.call]:
17009 If P is a class, and P has the form
17010 template-id, then A can be a derived class of
17011 the deduced A. Likewise, if P is a pointer to
17012 a class of the form template-id, A can be a
17013 pointer to a derived class pointed to by the
17014 deduced A. */
17021 }
17022 }
17026 /* Perhaps PARM is something like S<U> and ARG is S<int>.
17027 Then, we should unify `int' and `U'. */
17029 else
17030 /* There's no chance of unification succeeding. */
17035 }
17042 {
17045 tree a;
17051 /* CV qualifications for methods can never be deduced, they must
17052 match exactly. We need to check them explicitly here,
17053 because type_unification_real treats them as any other
17054 cv-qualified parameter. */
17056 && (!check_cv_quals_for_unify
17076 }
17079 /* Unify a pointer to member with a pointer to member function, which
17080 deduces the type of the member as a function type. */
17082 {
17083 tree method_type;
17084 tree fntype;
17086 /* Check top-level cv qualifiers */
17094 /* Determine the type of the function we are unifying against. */
17096 fntype =
17100 /* Extract the cv-qualifiers of the member function from the
17101 implicit object parameter and place them on the function
17102 type to be restored later. */
17105 }
17124 /* Matched cases are handled by the ARG == PARM test above. */
17128 /* A non-type template parameter that is a variable should be a
17129 an integral constant, in which case, it whould have been
17130 folded into its (constant) value. So we should not be getting
17131 a variable here. */
17142 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
17143 or UNDERLYING_TYPE nodes. */
17147 /* Unification fails if we hit an error node. */
17151 /* An unresolved overload is a nondeduced context. */
17156 /* We must be looking at an expression. This can happen with
17157 something like:
17159 template <int I>
17160 void foo(S<I>, S<I + 2>);
17162 This is a "nondeduced context":
17164 [deduct.type]
17166 The nondeduced contexts are:
17168 --A type that is a template-id in which one or more of
17169 the template-arguments is an expression that references
17170 a template-parameter.
17172 In these cases, we assume deduction succeeded, but don't
17173 actually infer any unifications. */
17178 else
17180 }
17181 }
17182 #undef RECUR_AND_CHECK_FAILURE
17183 \f
17184 /* Note that DECL can be defined in this translation unit, if
17185 required. */
17187 static void
17189 {
17190 tree clone;
17194 }
17196 /* Called if RESULT is explicitly instantiated, or is a member of an
17197 explicitly instantiated class. */
17199 void
17201 {
17204 /* If this entity has already been written out, it's too late to
17205 make any modifications. */
17210 /* The TREE_PUBLIC flag for function declarations will have been
17211 set correctly by tsubst. */
17214 /* This might have been set by an earlier implicit instantiation. */
17219 else
17220 {
17222 /* Always make artificials weak. */
17225 /* For WIN32 we also want to put explicit instantiations in
17226 linkonce sections. */
17229 }
17231 /* If EXTERN_P, then this function will not be emitted -- unless
17232 followed by an explicit instantiation, at which point its linkage
17233 will be adjusted. If !EXTERN_P, then this function will be
17234 emitted here. In neither circumstance do we want
17235 import_export_decl to adjust the linkage. */
17237 }
17239 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
17240 important template arguments. If any are missing, we check whether
17241 they're important by using error_mark_node for substituting into any
17242 args that were used for partial ordering (the ones between ARGS and END)
17243 and seeing if it bubbles up. */
17245 static bool
17247 {
17252 {
17255 }
17257 {
17261 }
17263 }
17265 /* Given two function templates PAT1 and PAT2, return:
17267 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
17268 -1 if PAT2 is more specialized than PAT1.
17269 0 if neither is more specialized.
17271 LEN indicates the number of parameters we should consider
17272 (defaulted parameters should not be considered).
17274 The 1998 std underspecified function template partial ordering, and
17275 DR214 addresses the issue. We take pairs of arguments, one from
17276 each of the templates, and deduce them against each other. One of
17277 the templates will be more specialized if all the *other*
17278 template's arguments deduce against its arguments and at least one
17279 of its arguments *does* *not* deduce against the other template's
17280 corresponding argument. Deduction is done as for class templates.
17281 The arguments used in deduction have reference and top level cv
17282 qualifiers removed. Iff both arguments were originally reference
17283 types *and* deduction succeeds in both directions, the template
17284 with the more cv-qualified argument wins for that pairing (if
17285 neither is more cv-qualified, they both are equal). Unlike regular
17286 deduction, after all the arguments have been deduced in this way,
17287 we do *not* verify the deduced template argument values can be
17288 substituted into non-deduced contexts.
17290 The logic can be a bit confusing here, because we look at deduce1 and
17291 targs1 to see if pat2 is at least as specialized, and vice versa; if we
17292 can find template arguments for pat1 to make arg1 look like arg2, that
17293 means that arg2 is at least as specialized as arg1. */
17295 int
17297 {
17310 /* Remove the this parameter from non-static member functions. If
17311 one is a non-static member function and the other is not a static
17312 member function, remove the first parameter from that function
17313 also. This situation occurs for operator functions where we
17314 locate both a member function (with this pointer) and non-member
17315 operator (with explicit first operand). */
17317 {
17322 }
17324 {
17327 {
17328 len--;
17330 }
17331 }
17333 /* If only one is a conversion operator, they are unordered. */
17337 /* Consider the return type for a conversion function */
17339 {
17342 len++;
17343 }
17345 processing_template_decl++;
17351 /* Stop when an ellipsis is seen. */
17353 {
17362 {
17363 /* When both arguments are pack expansions, we need only
17364 unify the patterns themselves. */
17368 /* This is the last comparison we need to do. */
17370 }
17373 {
17376 }
17379 {
17382 }
17388 {
17394 /* Setup the parameter vector, which contains only ARG1. */
17397 /* Setup the argument vector, which contains the remaining
17398 arguments. */
17407 /* We cannot deduce in the other direction, because ARG1 is
17408 a pack expansion but ARG2 is not. */
17410 }
17412 {
17418 /* Setup the parameter vector, which contains only ARG1. */
17421 /* Setup the argument vector, which contains the remaining
17422 arguments. */
17431 /* We cannot deduce in the other direction, because ARG2 is
17432 a pack expansion but ARG1 is not.*/
17434 }
17436 else
17437 {
17438 /* The normal case, where neither argument is a pack
17439 expansion. */
17446 }
17448 /* If we couldn't deduce arguments for tparms1 to make arg1 match
17449 arg2, then arg2 is not as specialized as arg1. */
17455 /* "If, for a given type, deduction succeeds in both directions
17456 (i.e., the types are identical after the transformations above)
17457 and if the type from the argument template is more cv-qualified
17458 than the type from the parameter template (as described above)
17459 that type is considered to be more specialized than the other. If
17460 neither type is more cv-qualified than the other then neither type
17461 is more specialized than the other." */
17465 {
17470 }
17473 /* We've failed to deduce something in either direction.
17474 These must be unordered. */
17479 /* We have already processed all of the arguments in our
17480 handing of the pack expansion type. */
17485 }
17487 /* "In most cases, all template parameters must have values in order for
17488 deduction to succeed, but for partial ordering purposes a template
17489 parameter may remain without a value provided it is not used in the
17490 types being used for partial ordering."
17492 Thus, if we are missing any of the targs1 we need to substitute into
17493 origs1, then pat2 is not as specialized as pat1. This can happen when
17494 there is a nondeduced context. */
17500 processing_template_decl--;
17502 /* All things being equal, if the next argument is a pack expansion
17503 for one function but not for the other, prefer the
17504 non-variadic function. FIXME this is bogus; see c++/41958. */
17508 {
17511 }
17517 else
17519 }
17521 /* Determine which of two partial specializations of MAIN_TMPL is more
17522 specialized.
17524 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
17525 to the first partial specialization. The TREE_VALUE is the
17526 innermost set of template parameters for the partial
17527 specialization. PAT2 is similar, but for the second template.
17529 Return 1 if the first partial specialization is more specialized;
17530 -1 if the second is more specialized; 0 if neither is more
17531 specialized.
17533 See [temp.class.order] for information about determining which of
17534 two templates is more specialized. */
17536 static int
17538 {
17539 tree targs;
17547 /* Just like what happens for functions, if we are ordering between
17548 different class template specializations, we may encounter dependent
17549 types in the arguments, and we need our dependency check functions
17550 to behave correctly. */
17556 {
17559 }
17565 {
17568 }
17571 /* In the case of a tie where at least one of the class templates
17572 has a parameter pack at the end, the template with the most
17573 non-packed parameters wins. */
17575 && any_deductions
17578 {
17584 /* We don't count the pack expansion at the end. */
17594 }
17597 }
17599 /* Return the template arguments that will produce the function signature
17600 DECL from the function template FN, with the explicit template
17601 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
17602 also match. Return NULL_TREE if no satisfactory arguments could be
17603 found. */
17605 static tree
17607 {
17611 tree decl_arg_types;
17614 tree arg;
17618 /* Never do unification on the 'this' parameter. */
17639 }
17641 /* Return the innermost template arguments that, when applied to a partial
17642 specialization of MAIN_TMPL whose innermost template parameters are
17643 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
17644 ARGS.
17646 For example, suppose we have:
17648 template <class T, class U> struct S {};
17649 template <class T> struct S<T*, int> {};
17651 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
17652 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
17653 int}. The resulting vector will be {double}, indicating that `T'
17654 is bound to `double'. */
17656 static tree
17658 {
17660 tree deduced_args;
17661 tree innermost_deduced_args;
17665 {
17669 innermost_deduced_args);
17670 }
17671 else
17684 /* Verify that nondeduced template arguments agree with the type
17685 obtained from argument deduction.
17687 For example:
17689 struct A { typedef int X; };
17690 template <class T, class U> struct C {};
17691 template <class T> struct C<T, typename T::X> {};
17693 Then with the instantiation `C<A, int>', we can deduce that
17694 `T' is `A' but unify () does not check whether `typename T::X'
17695 is `int'. */
17701 /* We only need to check the innermost arguments; the other
17702 arguments will always agree. */
17707 /* Now that we have bindings for all of the template arguments,
17708 ensure that the arguments deduced for the template template
17709 parameters have compatible template parameter lists. See the use
17710 of template_template_parm_bindings_ok_p in fn_type_unification
17711 for more information. */
17716 }
17718 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
17719 Return the TREE_LIST node with the most specialized template, if
17720 any. If there is no most specialized template, the error_mark_node
17721 is returned.
17723 Note that this function does not look at, or modify, the
17724 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
17725 returned is one of the elements of INSTANTIATIONS, callers may
17726 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
17727 and retrieve it from the value returned. */
17729 tree
17731 {
17738 {
17744 fate--;
17749 fate++;
17754 {
17755 /* Equally specialized, move to next function. If there
17756 is no next function, nothing's most specialized. */
17761 }
17762 }
17765 /* Now verify that champ is better than everything earlier in the
17766 instantiation list. */
17774 {
17777 }
17779 processing_template_decl--;
17785 }
17787 /* If DECL is a specialization of some template, return the most
17788 general such template. Otherwise, returns NULL_TREE.
17790 For example, given:
17792 template <class T> struct S { template <class U> void f(U); };
17794 if TMPL is `template <class U> void S<int>::f(U)' this will return
17795 the full template. This function will not trace past partial
17796 specializations, however. For example, given in addition:
17798 template <class T> struct S<T*> { template <class U> void f(U); };
17800 if TMPL is `template <class U> void S<int*>::f(U)' this will return
17801 `template <class T> template <class U> S<T*>::f(U)'. */
17803 tree
17805 {
17806 /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is
17807 an immediate specialization. */
17809 {
17813 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a
17814 template friend. */
17819 }
17821 /* Look for more and more general templates. */
17823 {
17824 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
17825 (See cp-tree.h for details.) */
17833 /* Stop if we run into an explicitly specialized class template. */
17840 }
17843 }
17845 /* Return the most specialized of the class template partial
17846 specializations of TMPL which can produce TYPE, a specialization of
17847 TMPL. The value returned is actually a TREE_LIST; the TREE_TYPE is
17848 a _TYPE node corresponding to the partial specialization, while the
17849 TREE_PURPOSE is the set of template arguments that must be
17850 substituted into the TREE_TYPE in order to generate TYPE.
17852 If the choice of partial specialization is ambiguous, a diagnostic
17853 is issued, and the error_mark_node is returned. If there are no
17854 partial specializations of TMPL matching TYPE, then NULL_TREE is
17855 returned. */
17857 static tree
17859 {
17861 tree t;
17862 tree champ;
17865 tree args;
17871 /* For determining which partial specialization to use, only the
17872 innermost args are interesting. */
17874 {
17877 }
17880 {
17881 tree partial_spec_args;
17882 tree spec_args;
17890 {
17893 /* Discard the outer levels of args, and then substitute in the
17894 template args from the enclosing class. */
17896 partial_spec_args = tsubst_template_args
17899 /* PARMS already refers to just the innermost parms, but the
17900 template parms in partial_spec_args had their levels lowered
17901 by tsubst, so we need to do the same for the parm list. We
17902 can't just tsubst the TREE_VEC itself, as tsubst wants to
17903 treat a TREE_VEC as an argument vector. */
17909 }
17911 partial_spec_args =
17914 partial_spec_args),
17925 partial_spec_args,
17926 args);
17928 {
17933 }
17934 }
17944 {
17947 ;
17948 else
17949 {
17951 {
17954 {
17957 }
17958 }
17960 }
17961 }
17965 {
17968 {
17971 }
17972 }
17975 {
17983 {
17986 }
17989 }
17992 }
17994 /* Explicitly instantiate DECL. */
17996 void
17998 {
18003 /* An error occurred, for which grokdeclarator has already issued
18004 an appropriate message. */
18007 {
18010 }
18012 {
18013 /* There is an asymmetry here in the way VAR_DECLs and
18014 FUNCTION_DECLs are handled by grokdeclarator. In the case of
18015 the latter, the DECL we get back will be marked as a
18016 template instantiation, and the appropriate
18017 DECL_TEMPLATE_INFO will be set up. This does not happen for
18018 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
18019 should handle VAR_DECLs as it currently handles
18020 FUNCTION_DECLs. */
18022 {
18025 }
18028 {
18031 }
18033 {
18038 }
18039 }
18041 {
18044 }
18045 else
18048 /* Check for various error cases. Note that if the explicit
18049 instantiation is valid the RESULT will currently be marked as an
18050 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
18051 until we get here. */
18054 {
18055 /* DR 259 [temp.spec].
18057 Both an explicit instantiation and a declaration of an explicit
18058 specialization shall not appear in a program unless the explicit
18059 instantiation follows a declaration of the explicit specialization.
18061 For a given set of template parameters, if an explicit
18062 instantiation of a template appears after a declaration of an
18063 explicit specialization for that template, the explicit
18064 instantiation has no effect. */
18066 }
18068 {
18069 /* [temp.spec]
18071 No program shall explicitly instantiate any template more
18072 than once.
18074 We check DECL_NOT_REALLY_EXTERN so as not to complain when
18075 the first instantiation was `extern' and the second is not,
18076 and EXTERN_P for the opposite case. */
18079 /* If an "extern" explicit instantiation follows an ordinary
18080 explicit instantiation, the template is instantiated. */
18083 }
18085 {
18088 }
18090 {
18093 }
18096 ;
18098 {
18101 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
18104 }
18105 else
18113 }
18115 static void
18117 {
18123 {
18126 }
18127 }
18129 /* Called from do_type_instantiation through binding_table_foreach to
18130 do recursive instantiation for the type bound in ENTRY. */
18131 static void
18133 {
18139 }
18141 /* Called from do_type_instantiation to instantiate a member
18142 (a member function or a static member variable) of an
18143 explicitly instantiated class template. */
18144 static void
18146 {
18151 }
18153 /* Perform an explicit instantiation of template class T. STORAGE, if
18154 non-null, is the RID for extern, inline or static. COMPLAIN is
18155 nonzero if this is called from the parser, zero if called recursively,
18156 since the standard is unclear (as detailed below). */
18158 void
18160 {
18170 {
18171 tree tmpl =
18175 else
18178 }
18183 {
18186 t);
18188 }
18191 {
18193 {
18195 {
18198 "ISO C++ 1998 forbids the use of %<extern%> on "
18200 }
18201 else
18203 "ISO C++ forbids the use of %qE"
18205 }
18213 else
18214 {
18216 storage);
18218 }
18219 }
18222 {
18223 /* DR 259 [temp.spec].
18225 Both an explicit instantiation and a declaration of an explicit
18226 specialization shall not appear in a program unless the explicit
18227 instantiation follows a declaration of the explicit specialization.
18229 For a given set of template parameters, if an explicit
18230 instantiation of a template appears after a declaration of an
18231 explicit specialization for that template, the explicit
18232 instantiation has no effect. */
18234 }
18236 {
18237 /* [temp.spec]
18239 No program shall explicitly instantiate any template more
18240 than once.
18242 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
18243 instantiation was `extern'. If EXTERN_P then the second is.
18244 These cases are OK. */
18251 /* If we've already instantiated the template, just return now. */
18254 }
18262 {
18263 tree tmp;
18265 /* In contrast to implicit instantiation, where only the
18266 declarations, and not the definitions, of members are
18267 instantiated, we have here:
18269 [temp.explicit]
18271 The explicit instantiation of a class template specialization
18272 implies the instantiation of all of its members not
18273 previously explicitly specialized in the translation unit
18274 containing the explicit instantiation.
18276 Of course, we can't instantiate member template classes, since
18277 we don't have any arguments for them. Note that the standard
18278 is unclear on whether the instantiation of the members are
18279 *explicit* instantiations or not. However, the most natural
18280 interpretation is that it should be an explicit instantiation. */
18295 }
18296 }
18298 /* Given a function DECL, which is a specialization of TMPL, modify
18299 DECL to be a re-instantiation of TMPL with the same template
18300 arguments. TMPL should be the template into which tsubst'ing
18301 should occur for DECL, not the most general template.
18303 One reason for doing this is a scenario like this:
18305 template <class T>
18306 void f(const T&, int i);
18308 void g() { f(3, 7); }
18310 template <class T>
18311 void f(const T& t, const int i) { }
18313 Note that when the template is first instantiated, with
18314 instantiate_template, the resulting DECL will have no name for the
18315 first parameter, and the wrong type for the second. So, when we go
18316 to instantiate the DECL, we regenerate it. */
18318 static void
18320 {
18321 /* The arguments used to instantiate DECL, from the most general
18322 template. */
18323 tree args;
18324 tree code_pattern;
18329 /* Make sure that we can see identifiers, and compute access
18330 correctly. */
18334 {
18335 tree decl_parm;
18336 tree pattern_parm;
18337 tree specs;
18351 specs);
18353 /* Merge parameter declarations. */
18356 pattern_parm
18360 {
18361 tree parm_type;
18362 tree attributes;
18367 NULL_TREE);
18373 {
18376 }
18379 }
18380 /* Merge any parameters that match with the function parameter
18381 pack. */
18383 {
18385 tree expanded_types;
18386 /* Expand the TYPE_PACK_EXPANSION that provides the types for
18387 the parameters in this function parameter pack. */
18392 {
18393 tree parm_type;
18394 tree attributes;
18397 /* Rename the parameter to include the index. */
18406 {
18409 }
18411 }
18412 }
18413 /* Merge additional specifiers from the CODE_PATTERN. */
18417 }
18419 {
18427 }
18428 else
18432 }
18434 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
18435 substituted to get DECL. */
18437 tree
18439 {
18442 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
18443 for the instantiation. This is not always the most general
18444 template. Consider, for example:
18446 template <class T>
18447 struct S { template <class U> void f();
18448 template <> void f<int>(); };
18450 and an instantiation of S<double>::f<int>. We want TD to be the
18451 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
18453 more general template. */
18455 /* We must also deal with friend templates. Given:
18457 template <class T> struct S {
18458 template <class U> friend void f() {};
18459 };
18461 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
18462 so far as the language is concerned, but that's still
18463 where we get the pattern for the instantiation from. On
18464 other hand, if the definition comes outside the class, say:
18466 template <class T> struct S {
18467 template <class U> friend void f();
18468 };
18469 template <class U> friend void f() {}
18471 we don't need to look any further. That's what the check for
18472 DECL_INITIAL is for. */
18476 {
18477 /* The present template, TD, should not be a definition. If it
18478 were a definition, we should be using it! Note that we
18479 cannot restructure the loop to just keep going until we find
18480 a template with a definition, since that might go too far if
18481 a specialization was declared, but not defined. */
18485 /* Fetch the more general template. */
18487 }
18490 }
18492 /* Returns true if we need to instantiate this template instance even if we
18493 know we aren't going to emit it.. */
18495 bool
18497 {
18498 /* We always instantiate inline functions so that we can inline them. An
18499 explicit instantiation declaration prohibits implicit instantiation of
18500 non-inline functions. With high levels of optimization, we would
18501 normally inline non-inline functions -- but we're not allowed to do
18502 that for "extern template" functions. Therefore, we check
18503 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
18507 /* And we need to instantiate static data members so that
18508 their initializers are available in integral constant
18509 expressions. */
18512 }
18514 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
18515 instantiate it now, modifying TREE_TYPE (fn). */
18517 void
18519 {
18533 {
18535 {
18550 }
18551 else
18553 }
18554 else
18555 {
18556 /* This is an implicitly declared function, so NOEX is a list of
18557 other functions to evaluate and merge. */
18558 tree elt;
18561 {
18563 tree subspec;
18567 }
18568 }
18573 {
18576 else
18578 }
18579 }
18581 /* Produce the definition of D, a _DECL generated from a template. If
18582 DEFER_OK is nonzero, then we don't have to actually do the
18583 instantiation now; we just have to do it sometime. Normally it is
18584 an error if this is an explicit instantiation but D is undefined.
18585 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
18586 explicitly instantiated class template. */
18588 tree
18591 {
18593 tree gen_args;
18594 tree args;
18595 tree td;
18596 tree code_pattern;
18597 tree spec;
18598 tree gen_tmpl;
18602 tree fn_context;
18605 /* This function should only be used to instantiate templates for
18606 functions and static member variables. */
18609 /* Variables are never deferred; if instantiation is required, they
18610 are instantiated right away. That allows for better code in the
18611 case that an expression refers to the value of the variable --
18612 if the variable has a constant value the referring expression can
18613 take advantage of that fact. */
18618 /* Don't instantiate cloned functions. Instead, instantiate the
18619 functions they cloned. */
18627 /* D has already been instantiated or explicitly specialized, so
18628 there's nothing for us to do here.
18630 It might seem reasonable to check whether or not D is an explicit
18631 instantiation, and, if so, stop here. But when an explicit
18632 instantiation is deferred until the end of the compilation,
18633 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
18634 the instantiation. */
18637 /* Check to see whether we know that this template will be
18638 instantiated in some other file, as with "extern template"
18639 extension. */
18642 /* In general, we do not instantiate such templates. */
18650 /* We should already have the extra args. */
18653 /* And what's in the hash table should match D. */
18657 /* This needs to happen before any tsubsting. */
18663 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
18664 for the instantiation. */
18668 /* We should never be trying to instantiate a member of a class
18669 template or partial specialization. */
18674 /* In the case of a friend template whose definition is provided
18675 outside the class, we may have too many arguments. Drop the
18676 ones we don't need. The same is true for specializations. */
18677 args = get_innermost_template_args
18679 else
18685 else
18688 /* We may be in the middle of deferred access check. Disable it now. */
18691 /* Unless an explicit instantiation directive has already determined
18692 the linkage of D, remember that a definition is available for
18693 this entity. */
18703 /* If D is a member of an explicitly instantiated class template,
18704 and no definition is available, treat it like an implicit
18705 instantiation. */
18708 {
18709 /* Leave linkage flags alone on instantiations with anonymous
18710 visibility. */
18712 {
18715 }
18717 }
18722 /* Defer all other templates, unless we have been explicitly
18723 forbidden from doing so. */
18725 template. */
18726 ! pattern_defined
18727 /* If it's OK to postpone instantiation, do so. */
18728 || defer_ok
18729 /* If this is a static data member that will be defined
18730 elsewhere, we don't want to instantiate the entire data
18731 member, but we do want to instantiate the initializer so that
18732 we can substitute that elsewhere. */
18734 {
18735 /* The definition of the static data member is now required so
18736 we must substitute the initializer. */
18740 {
18741 tree ns;
18742 tree init;
18749 args,
18752 /* Make sure the initializer is still constant, in case of
18753 circular dependency (template/instantiate6.C). */
18754 const_init
18758 LOOKUP_ONLYCONVERTING);
18761 }
18763 /* We restore the source position here because it's used by
18764 add_pending_template. */
18770 /* [temp.explicit]
18772 The definition of a non-exported function template, a
18773 non-exported member function template, or a non-exported
18774 member function or static data member of a class template
18775 shall be present in every translation unit in which it is
18776 explicitly instantiated. */
18780 /* If we're in unevaluated context, we just wanted to get the
18781 constant value; this isn't an odr use, so don't queue
18782 a full instantiation. */
18785 /* ??? Historically, we have instantiated inline functions, even
18786 when marked as "extern template". */
18790 }
18791 /* Tell the repository that D is available in this translation unit
18792 -- and see if it is supposed to be instantiated here. */
18794 {
18795 /* In a PCH file, despite the fact that the repository hasn't
18796 requested instantiation in the PCH it is still possible that
18797 an instantiation will be required in a file that includes the
18798 PCH. */
18801 /* Instantiate inline functions so that the inliner can do its
18802 job, even though we'll not be emitting a copy of this
18803 function. */
18806 }
18815 /* Mark D as instantiated so that recursive calls to
18816 instantiate_decl do not try to instantiate it again. */
18819 /* Regenerate the declaration in case the template has been modified
18820 by a subsequent redeclaration. */
18823 /* We already set the file and line above. Reset them now in case
18824 they changed as a result of calling regenerate_decl_from_template. */
18828 {
18829 tree init;
18832 /* Clear out DECL_RTL; whatever was there before may not be right
18833 since we've reset the type of the declaration. */
18837 /* The initializer is placed in DECL_INITIAL by
18838 regenerate_decl_from_template so we don't need to
18839 push/pop_access_scope again here. Pull it out so that
18840 cp_finish_decl can process it. */
18845 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
18846 initializer. That function will defer actual emission until
18847 we have a chance to determine linkage. */
18850 /* Enter the scope of D so that access-checking works correctly. */
18855 }
18859 {
18861 tree subst_decl;
18862 tree tmpl_parm;
18863 tree spec_parm;
18865 /* Save away the current list, in case we are instantiating one
18866 template from within the body of another. */
18869 /* Set up the list of local specializations. */
18872 /* Set up context. */
18875 /* Some typedefs referenced from within the template code need to be
18876 access checked at template instantiation time, i.e now. These
18877 types were added to the template at parsing time. Let's get those
18878 and perform the access checks then. */
18880 gen_args);
18882 /* Create substitution entries for the parameters. */
18887 {
18891 }
18893 {
18895 {
18898 }
18899 else
18900 {
18901 /* Register the (value) argument pack as a specialization of
18902 TMPL_PARM, then move on. */
18905 }
18906 }
18909 /* Substitute into the body of the function. */
18914 /* Set the current input_location to the end of the function
18915 so that finish_function knows where we are. */
18918 /* We don't need the local specializations any more. */
18922 /* Finish the function. */
18925 }
18927 /* We're not deferring instantiation any more. */
18935 out:
18943 }
18945 /* Run through the list of templates that we wish we could
18946 instantiate, and instantiate any we can. RETRIES is the
18947 number of times we retry pending template instantiation. */
18949 void
18951 {
18955 /* Instantiating templates may trigger vtable generation. This in turn
18956 may require further template instantiations. We place a limit here
18957 to avoid infinite loop. */
18959 {
18963 " instantiating %q+D, possibly from virtual table generation"
18967 /* Pretend that we defined it. */
18970 }
18972 do
18973 {
18978 {
18983 {
18984 tree fn;
18987 {
18991 fn;
18999 }
19002 }
19003 else
19004 {
19007 {
19008 instantiation
19014 }
19018 }
19021 /* If INSTANTIATION has been instantiated, then we don't
19022 need to consider it again in the future. */
19024 else
19025 {
19028 }
19031 }
19033 }
19037 }
19039 /* Substitute ARGVEC into T, which is a list of initializers for
19040 either base class or a non-static data member. The TREE_PURPOSEs
19041 are DECLs, and the TREE_VALUEs are the initializer values. Used by
19042 instantiate_decl. */
19044 static tree
19046 {
19050 {
19051 tree decl;
19052 tree init;
19058 {
19059 tree expr;
19060 tree arg;
19062 /* Expand the base class expansion type into separate base
19063 classes. */
19065 tf_warning_or_error,
19066 NULL_TREE);
19070 /* We'll be building separate TREE_LISTs of arguments for
19071 each base. */
19077 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
19078 expand each argument in the TREE_VALUE of t. */
19085 /* VOID_TYPE_NODE is used to indicate
19086 value-initialization. */
19087 {
19090 }
19091 else
19092 {
19093 /* Substitute parameter packs into each argument in the
19094 TREE_LIST. */
19097 {
19098 tree expanded_exprs;
19100 /* Expand the argument. */
19102 expanded_exprs
19104 tf_warning_or_error,
19105 NULL_TREE);
19109 /* Prepend each of the expanded expressions to the
19110 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
19112 {
19117 }
19118 }
19121 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
19122 since we built them backwards. */
19124 {
19127 }
19128 }
19129 }
19132 {
19134 {
19138 }
19139 else
19140 {
19141 tree tmp;
19156 /* If we had an initializer but it instantiated to nothing,
19157 value-initialize the object. This will only occur when
19158 the initializer was a pack expansion where the parameter
19159 packs used in that expansion were of length zero. */
19162 }
19165 {
19169 }
19170 }
19171 }
19173 }
19175 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
19177 static void
19179 {
19184 else
19186 }
19188 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
19189 is the instantiation (which should have been created with
19190 start_enum) and ARGS are the template arguments to use. */
19192 static void
19194 {
19195 tree e;
19201 {
19202 tree value;
19203 tree decl;
19206 /* Note that in a template enum, the TREE_VALUE is the
19207 CONST_DECL, not the corresponding INTEGER_CST. */
19212 /* Give this enumeration constant the correct access. */
19215 /* Actually build the enumerator itself. */
19216 build_enumerator
19218 }
19228 }
19230 /* DECL is a FUNCTION_DECL that is a template specialization. Return
19231 its type -- but without substituting the innermost set of template
19232 arguments. So, innermost set of template parameters will appear in
19233 the type. */
19235 tree
19237 {
19238 tree fn_type;
19239 tree tmpl;
19240 tree targs;
19241 tree tparms;
19249 /* There should be as many levels of arguments as there are levels
19250 of parameters. */
19256 /* No substitution is necessary. */
19257 ;
19258 else
19259 {
19261 tree partial_args;
19263 /* Replace the innermost level of the TARGS with NULL_TREEs to
19264 let tsubst know not to substitute for those parameters. */
19273 /* Make sure that we can see identifiers, and compute access
19274 correctly. */
19278 /* Now, do the (partial) substitution to figure out the
19279 appropriate function type. */
19283 /* Substitute into the template parameters to obtain the real
19284 innermost set of parameters. This step is important if the
19285 innermost set of template parameters contains value
19286 parameters whose types depend on outer template parameters. */
19291 }
19294 }
19296 /* Return truthvalue if we're processing a template different from
19297 the last one involved in diagnostics. */
19298 int
19300 {
19302 }
19304 /* Remember current template involved in diagnostics. */
19305 void
19307 {
19309 }
19313 {
19315 }
19317 /* [temp.param] Check that template non-type parm TYPE is of an allowable
19318 type. Return zero for ok, nonzero for disallowed. Issue error and
19319 warning messages under control of COMPLAIN. */
19321 static int
19323 {
19340 {
19343 else
19345 type);
19346 }
19348 }
19350 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
19351 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
19353 static bool
19355 {
19356 tree scope;
19358 /* [temp.dep.type]
19360 A type is dependent if it is:
19362 -- a template parameter. Template template parameters are types
19363 for us (since TYPE_P holds true for them) so we handle
19364 them here. */
19368 /* -- a qualified-id with a nested-name-specifier which contains a
19369 class-name that names a dependent type or whose unqualified-id
19370 names a dependent type. */
19373 /* -- a cv-qualified type where the cv-unqualified type is
19374 dependent. */
19376 /* -- a compound type constructed from any dependent type. */
19386 {
19387 tree arg_type;
19392 arg_type;
19397 }
19398 /* -- an array type constructed from any dependent type or whose
19399 size is specified by a constant expression that is
19400 value-dependent.
19402 We checked for type- and value-dependence of the bounds in
19403 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
19405 {
19410 }
19412 /* -- a template-id in which either the template name is a template
19413 parameter ... */
19416 /* ... or any of the template arguments is a dependent type or
19417 an expression that is type-dependent or value-dependent. */
19419 && (any_dependent_template_arguments_p
19423 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
19424 dependent; if the argument of the `typeof' expression is not
19425 type-dependent, then it should already been have resolved. */
19431 /* A template argument pack is dependent if any of its packed
19432 arguments are. */
19434 {
19440 }
19442 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
19443 be template parameters. */
19447 /* The standard does not specifically mention types that are local
19448 to template functions or local classes, but they should be
19449 considered dependent too. For example:
19451 template <int I> void f() {
19452 enum E { a = I };
19453 S<sizeof (E)> s;
19454 }
19456 The size of `E' cannot be known until the value of `I' has been
19457 determined. Therefore, `E' must be considered dependent. */
19461 /* Don't use type_dependent_expression_p here, as it can lead
19462 to infinite recursion trying to determine whether a lambda
19463 nested in a lambda is dependent (c++/47687). */
19467 && (any_dependent_template_arguments_p
19471 /* Other types are non-dependent. */
19473 }
19475 /* Returns TRUE if TYPE is dependent, in the sense of
19476 [temp.dep.type]. Note that a NULL type is considered dependent. */
19478 bool
19480 {
19481 /* If there are no template parameters in scope, then there can't be
19482 any dependent types. */
19484 {
19485 /* If we are not processing a template, then nobody should be
19486 providing us with a dependent type. */
19490 }
19492 /* If the type is NULL, we have not computed a type for the entity
19493 in question; in that case, the type is dependent. */
19497 /* Erroneous types can be considered non-dependent. */
19501 /* If we have not already computed the appropriate value for TYPE,
19502 do so now. */
19504 {
19507 }
19510 }
19512 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
19513 lookup. In other words, a dependent type that is not the current
19514 instantiation. */
19516 bool
19518 {
19521 }
19523 /* T is a SCOPE_REF; return whether we need to consider it
19524 instantiation-dependent so that we can check access at instantiation
19525 time even though we know which member it resolves to. */
19527 static bool
19529 {
19535 else
19537 }
19539 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
19540 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
19541 expression. */
19543 /* Note that this predicate is not appropriate for general expressions;
19544 only constant expressions (that satisfy potential_constant_expression)
19545 can be tested for value dependence. */
19547 bool
19549 {
19553 /* A name declared with a dependent type. */
19558 {
19560 /* A name that has not been looked up -- must be dependent. */
19564 /* A non-type template parm. */
19568 /* A non-type template parm. */
19574 /* A constant with literal type and is initialized
19575 with an expression that is value-dependent.
19577 Note that a non-dependent parenthesized initializer will have
19578 already been replaced with its constant value, so if we see
19579 a TREE_LIST it must be dependent. */
19592 /* These expressions are value-dependent if the type to which
19593 the cast occurs is dependent or the expression being casted
19594 is value-dependent. */
19595 {
19601 /* A functional cast has a list of operands. */
19604 {
19605 /* If there are no operands, it must be an expression such
19606 as "int()". This should not happen for aggregate types
19607 because it would form non-constant expressions. */
19612 }
19618 }
19623 /* FALLTHRU */
19626 /* A `sizeof' expression is value-dependent if the operand is
19627 type-dependent or is a pack expansion. */
19636 /* An 'encode' expression is value-dependent if the operand is
19637 type-dependent. */
19646 /* All instantiation-dependent expressions should also be considered
19647 value-dependent. */
19655 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
19656 is value-dependent. */
19657 {
19666 }
19669 {
19673 }
19684 {
19688 }
19691 {
19698 {
19700 /* In a call to a constexpr member function, look through the
19701 implicit ADDR_EXPR on the object argument so that it doesn't
19702 cause the call to be considered value-dependent. We also
19703 look through it in potential_constant_expression. */
19710 }
19712 }
19715 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
19716 type-dependent. */
19720 {
19722 tree val;
19727 }
19730 /* Treat a GNU statement expression as dependent to avoid crashing
19731 under fold_non_dependent_expr; it can't be constant. */
19735 /* A constant expression is value-dependent if any subexpression is
19736 value-dependent. */
19738 {
19745 {
19749 {
19752 /* In some cases, some of the operands may be missing.l
19753 (For example, in the case of PREDECREMENT_EXPR, the
19754 amount to increment by may be missing.) That doesn't
19755 make the expression dependent. */
19758 }
19759 }
19763 }
19765 }
19767 /* The expression is not value-dependent. */
19769 }
19771 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
19772 [temp.dep.expr]. Note that an expression with no type is
19773 considered dependent. Other parts of the compiler arrange for an
19774 expression with type-dependent subexpressions to have no type, so
19775 this function doesn't have to be fully recursive. */
19777 bool
19779 {
19786 /* An unresolved name is always dependent. */
19790 /* Some expression forms are never type-dependent. */
19803 /* The types of these expressions depends only on the type to which
19804 the cast occurs. */
19813 /* The types of these expressions depends only on the type created
19814 by the expression. */
19817 {
19818 /* For NEW_EXPR tree nodes created inside a template, either
19819 the object type itself or a TREE_LIST may appear as the
19820 operand 1. */
19823 /* This is an array type. We need to check array dimensions
19824 as well. */
19826 || value_dependent_expression_p
19828 else
19830 }
19833 {
19837 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
19838 contains an identifier associated by name lookup with one or more
19839 declarations declared with a dependent type, or...a
19840 nested-name-specifier or qualified-id that names a member of an
19841 unknown specialization. */
19844 }
19849 && (any_dependent_template_arguments_p
19861 {
19862 tree elt;
19866 {
19869 }
19871 }
19873 /* A static data member of the current instantiation with incomplete
19874 array type is type-dependent, as the definition and specializations
19875 can have different bounds. */
19883 {
19888 {
19894 }
19895 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
19903 {
19908 }
19913 {
19917 }
19919 }
19924 }
19926 /* walk_tree callback function for instantiation_dependent_expression_p,
19927 below. Returns non-zero if a dependent subexpression is found. */
19929 static tree
19932 {
19934 {
19935 /* We don't have to worry about decltype currently because decltype
19936 of an instantiation-dependent expr is a dependent type. This
19937 might change depending on the resolution of DR 1172. */
19940 }
19943 {
19944 /* Don't treat an argument list as dependent just because it has no
19945 TREE_TYPE. */
19952 /* A constant with a dependent initializer is dependent. */
19960 /* Handle expressions with type operands. */
19965 {
19970 {
19973 else
19974 {
19977 }
19978 }
19980 }
19991 /* In a template, finish_class_member_access_expr creates a
19992 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
19993 type-dependent, so that we can check access control at
19994 instantiation time (PR 42277). See also Core issue 1273. */
20001 else
20004 /* Treat statement-expressions as dependent. */
20010 }
20014 else
20016 }
20018 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
20019 sense defined by the ABI:
20021 "An expression is instantiation-dependent if it is type-dependent
20022 or value-dependent, or it has a subexpression that is type-dependent
20023 or value-dependent." */
20025 bool
20027 {
20028 tree result;
20039 }
20041 /* Like type_dependent_expression_p, but it also works while not processing
20042 a template definition, i.e. during substitution or mangling. */
20044 bool
20046 {
20052 }
20054 /* Returns TRUE if ARGS contains a type-dependent expression. */
20056 bool
20058 {
20060 tree arg;
20063 {
20066 }
20068 }
20070 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
20071 expressions) contains any type-dependent expressions. */
20073 bool
20075 {
20081 }
20083 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
20084 expressions) contains any value-dependent expressions. */
20086 bool
20088 {
20094 }
20096 /* Returns TRUE if the ARG (a template argument) is dependent. */
20098 bool
20100 {
20104 /* Assume a template argument that was wrongly written by the user
20105 is dependent. This is consistent with what
20106 any_dependent_template_arguments_p [that calls this function]
20107 does. */
20118 {
20122 {
20125 }
20128 }
20131 else
20134 }
20136 /* Returns true if ARGS (a collection of template arguments) contains
20137 any types that require structural equality testing. */
20139 bool
20141 {
20151 {
20154 {
20160 {
20161 /* Look inside the argument pack. */
20164 }
20167 {
20181 }
20182 }
20183 }
20186 }
20188 /* Returns true if ARGS (a collection of template arguments) contains
20189 any dependent arguments. */
20191 bool
20193 {
20203 {
20208 }
20211 }
20213 /* Returns TRUE if the template TMPL is dependent. */
20215 bool
20217 {
20219 {
20221 {
20225 }
20227 }
20229 /* Template template parameters are dependent. */
20233 /* So are names that have not been looked up. */
20236 /* So are member templates of dependent classes. */
20240 }
20242 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
20244 bool
20246 {
20249 }
20251 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
20252 is dependent. */
20254 bool
20256 {
20263 {
20284 {
20288 }
20292 {
20296 {
20301 }
20302 }
20303 }
20306 }
20308 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
20309 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
20310 no such TYPE can be found. Note that this function peers inside
20311 uninstantiated templates and therefore should be used only in
20312 extremely limited situations. ONLY_CURRENT_P restricts this
20313 peering to the currently open classes hierarchy (which is required
20314 when comparing types). */
20316 tree
20318 {
20319 tree scope;
20320 tree name;
20321 tree decl;
20323 tree pushed_scope;
20324 tree result;
20329 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
20330 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
20331 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
20332 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
20333 identifier of the TYPENAME_TYPE anymore.
20334 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
20335 TYPENAME_TYPE instead, we avoid messing up with a possible
20336 typedef variant case. */
20339 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
20340 it first before we can figure out what NAME refers to. */
20342 {
20344 /* Given a class template A with a dependent base with nested type C,
20345 typedef typename A::C::C C will land us here, as trying to resolve
20346 the initial A::C leads to the local C typedef, which leads back to
20347 A::C::C. So we break the recursion now. */
20349 else
20351 }
20352 /* If we don't know what SCOPE refers to, then we cannot resolve the
20353 TYPENAME_TYPE. */
20356 /* If the SCOPE is a template type parameter, we have no way of
20357 resolving the name. */
20360 /* If the SCOPE is not the current instantiation, there's no reason
20361 to look inside it. */
20364 /* If this is a typedef, we don't want to look inside (c++/11987). */
20367 /* If SCOPE isn't the template itself, it will not have a valid
20368 TYPE_FIELDS list. */
20370 /* scope is either the template itself or a compatible instantiation
20371 like X<T>, so look up the name in the original template. */
20373 else
20374 /* scope is a partial instantiation, so we can't do the lookup or we
20375 will lose the template arguments. */
20377 /* Enter the SCOPE so that name lookup will be resolved as if we
20378 were in the class definition. In particular, SCOPE will no
20379 longer be considered a dependent type. */
20381 /* Look up the declaration. */
20383 tf_warning_or_error);
20387 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
20388 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
20393 {
20397 }
20400 {
20401 tree tmpl;
20402 tree args;
20403 /* Obtain the template and the arguments. */
20406 /* Instantiate the template. */
20412 }
20414 /* Leave the SCOPE. */
20418 /* If we failed to resolve it, return the original typename. */
20422 /* If lookup found a typename type, resolve that too. */
20424 {
20425 /* Ill-formed programs can cause infinite recursion here, so we
20426 must catch that. */
20430 }
20432 /* Qualify the resulting type. */
20438 }
20440 /* EXPR is an expression which is not type-dependent. Return a proxy
20441 for EXPR that can be used to compute the types of larger
20442 expressions containing EXPR. */
20444 tree
20446 {
20447 tree inner_expr;
20449 #ifdef ENABLE_CHECKING
20450 /* Try to get a constant value for all non-dependent expressions in
20451 order to expose bugs in *_dependent_expression_p and constexpr. */
20455 #endif
20457 /* Preserve OVERLOADs; the functions must be available to resolve
20458 types. */
20469 /* There is no need to return a proxy for a variable. */
20472 /* Preserve string constants; conversions from string constants to
20473 "char *" are allowed, even though normally a "const char *"
20474 cannot be used to initialize a "char *". */
20477 /* Preserve arithmetic constants, as an optimization -- there is no
20478 reason to create a new node. */
20481 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
20482 There is at least one place where we want to know that a
20483 particular expression is a throw-expression: when checking a ?:
20484 expression, there are special rules if the second or third
20485 argument is a throw-expression. */
20489 /* Don't wrap an initializer list, we need to be able to look inside. */
20493 /* Don't wrap a dummy object, we need to be able to test for it. */
20512 /* If the type is unknown, it can't really be non-dependent */
20515 /* Otherwise, build a NON_DEPENDENT_EXPR. */
20517 }
20519 /* ARGS is a vector of expressions as arguments to a function call.
20520 Replace the arguments with equivalent non-dependent expressions.
20521 This modifies ARGS in place. */
20523 void
20525 {
20527 tree arg;
20530 {
20534 }
20535 }
20537 /* Returns a type which represents 'auto'. We use a TEMPLATE_TYPE_PARM
20538 with a level one deeper than the actual template parms. */
20540 tree
20542 {
20555 }
20557 /* Given type ARG, return std::initializer_list<ARG>. */
20559 static tree
20561 {
20562 tree std_init_list = namespace_binding
20564 tree argvec;
20566 {
20570 }
20575 }
20577 /* Replace auto in TYPE with std::initializer_list<auto>. */
20579 static tree
20581 {
20588 }
20590 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
20591 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
20593 tree
20595 {
20604 /* Defining a subset of type-dependent expressions that we can deduce
20605 from ahead of time isn't worth the trouble. */
20608 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
20609 with either a new invented type template parameter U or, if the
20610 initializer is a braced-init-list (8.5.4), with
20611 std::initializer_list<U>. */
20627 {
20629 /* Try again at instantiation time. */
20632 /* If type is error_mark_node a diagnostic must have been
20633 emitted by now. Also, having a mention to '<type error>'
20634 in the diagnostic is not really useful to the user. */
20635 {
20639 else
20641 }
20643 }
20645 /* If the list of declarators contains more than one declarator, the type
20646 of each declared variable is determined as described above. If the
20647 type deduced for the template parameter U is not the same in each
20648 deduction, the program is ill-formed. */
20651 {
20657 else
20661 }
20667 }
20669 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
20670 result. */
20672 tree
20674 {
20675 tree argvec;
20682 /* For a late-specified return type in a template type-parameter, we
20683 need to add a dummy argument level for its parmlist. */
20684 argvec = add_to_template_args
20689 }
20691 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto'. */
20693 bool
20695 {
20699 else
20701 }
20703 /* Returns true iff TYPE contains a use of 'auto'. Since auto can only
20704 appear as a type-specifier for the declaration in question, we don't
20705 have to look through the whole type. */
20707 tree
20709 {
20726 }
20728 /* For a given template T, return the vector of typedefs referenced
20729 in T for which access check is needed at T instantiation time.
20730 T is either a FUNCTION_DECL or a RECORD_TYPE.
20731 Those typedefs were added to T by the function
20732 append_type_to_template_for_access_check. */
20736 {
20737 tree ti;
20748 {
20753 }
20756 }
20758 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
20759 tied to T. That list of typedefs will be access checked at
20760 T instantiation time.
20761 T is either a FUNCTION_DECL or a RECORD_TYPE.
20762 TYPE_DECL is a TYPE_DECL node representing a typedef.
20763 SCOPE is the scope through which TYPE_DECL is accessed.
20764 LOCATION is the location of the usage point of TYPE_DECL.
20766 This function is a subroutine of
20767 append_type_to_template_for_access_check. */
20769 static void
20771 tree type_decl,
20772 tree scope,
20773 location_t location)
20774 {
20775 qualified_typedef_usage_t typedef_usage;
20776 tree ti;
20783 && type_decl
20797 }
20799 /* Append TYPE_DECL to the template TEMPL.
20800 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
20801 At TEMPL instanciation time, TYPE_DECL will be checked to see
20802 if it can be accessed through SCOPE.
20803 LOCATION is the location of the usage point of TYPE_DECL.
20805 e.g. consider the following code snippet:
20807 class C
20808 {
20809 typedef int myint;
20810 };
20812 template<class U> struct S
20813 {
20814 C::myint mi; // <-- usage point of the typedef C::myint
20815 };
20817 S<char> s;
20819 At S<char> instantiation time, we need to check the access of C::myint
20820 In other words, we need to check the access of the myint typedef through
20821 the C scope. For that purpose, this function will add the myint typedef
20822 and the scope C through which its being accessed to a list of typedefs
20823 tied to the template S. That list will be walked at template instantiation
20824 time and access check performed on each typedefs it contains.
20825 Note that this particular code snippet should yield an error because
20826 myint is private to C. */
20828 void
20830 tree type_decl,
20831 tree scope,
20832 location_t location)
20833 {
20839 /* Make sure we don't append the type to the template twice. */
20846 }
20848 /* Set up the hash tables for template instantiations. */
20850 void
20852 {
20854 hash_specialization,
20855 eq_specializations,
20856 ggc_free);
20858 hash_specialization,
20859 eq_specializations,
20860 ggc_free);
20861 }
20863 /* Print stats about the template hash tables for -fstats. */
20865 void
20867 {
20876 }