| blob | 4a57dd39d7a7590d9b38f4c05d62882127ea80c9 |
1 /* Handle parameterized types (templates) for GNU C++.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
3 2001, 2002 Free Software Foundation, Inc.
4 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
5 Rewritten by Jason Merrill (jason@cygnus.com).
7 This file is part of GNU CC.
9 GNU CC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2, or (at your option)
12 any later version.
14 GNU CC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GNU CC; see the file COPYING. If not, write to
21 the Free Software Foundation, 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
24 /* Known bugs or deficiencies include:
26 all methods must be provided in header files; can't use a source
27 file that contains only the method templates and "just win". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
52 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
53 instantiations have been deferred, either because their definitions
54 were not yet available, or because we were putting off doing the
55 work. The TREE_PURPOSE of each entry is a SRCLOC indicating where
56 the instantiate request occurred; the TREE_VALUE is a either a DECL
57 (for a function or static data member), or a TYPE (for a class)
58 indicating what we are hoping to instantiate. */
71 /* A map from local variable declarations in the body of the template
72 presently being instantiated to the corresponding instantiated
73 local variables. */
76 #define obstack_chunk_alloc xmalloc
77 #define obstack_chunk_free free
79 #define UNIFY_ALLOW_NONE 0
80 #define UNIFY_ALLOW_MORE_CV_QUAL 1
81 #define UNIFY_ALLOW_LESS_CV_QUAL 2
82 #define UNIFY_ALLOW_DERIVED 4
83 #define UNIFY_ALLOW_INTEGER 8
84 #define UNIFY_ALLOW_OUTER_LEVEL 16
85 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
86 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
87 #define UNIFY_ALLOW_MAX_CORRECTION 128
90 virtual, or a base class of a virtual
91 base. */
93 type with the desired type. */
114 tree*));
172 /* Called once to initialize pt.c. */
174 void
176 {
180 }
182 /* Do any processing required when DECL (a member template declaration
183 using TEMPLATE_PARAMETERS as its innermost parameter list) is
184 finished. Returns the TEMPLATE_DECL corresponding to DECL, unless
185 it is a specialization, in which case the DECL itself is returned. */
187 tree
189 tree decl;
190 {
194 /* By returning NULL_TREE, the parser will just ignore this
195 declaration. We have already issued the error. */
198 {
199 /* Assume that the class is the only declspec. */
203 {
207 }
209 }
213 {
215 {
218 }
219 else
221 }
222 else
226 }
228 /* Returns the template nesting level of the indicated class TYPE.
230 For example, in:
231 template <class T>
232 struct A
233 {
234 template <class U>
235 struct B {};
236 };
238 A<T>::B<U> has depth two, while A<T> has depth one.
239 Both A<T>::B<int> and A<int>::B<U> have depth one, if
240 COUNT_SPECIALIZATIONS is 0 or if they are instantiations, not
241 specializations.
243 This function is guaranteed to return 0 if passed NULL_TREE so
244 that, for example, `template_class_depth (current_class_type)' is
245 always safe. */
247 static int
249 tree type;
251 {
258 {
260 {
263 && ((count_specializations
267 }
268 else
269 {
272 && ((count_specializations
276 }
277 }
280 }
282 /* Returns the template nesting level of the indicated class TYPE.
283 Like template_class_depth_real, but instantiations do not count in
284 the depth. */
286 int
288 tree type;
289 {
291 }
293 /* Returns 1 if processing DECL as part of do_pending_inlines
294 needs us to push template parms. */
296 static int
298 tree decl;
299 {
305 }
307 /* Subroutine of maybe_begin_member_template_processing.
308 Push the template parms in PARMS, starting from LEVELS steps into the
309 chain, and ending at the beginning, since template parms are listed
310 innermost first. */
312 static void
314 tree parmlist;
316 {
324 current_template_parms
331 {
336 {
343 {
344 /* Make a CONST_DECL as is done in process_template_parm.
345 It is ugly that we recreate this here; the original
346 version built in process_template_parm is no longer
347 available. */
354 }
359 }
360 }
361 }
363 /* Restore the template parameter context for a member template or
364 a friend template defined in a class definition. */
366 void
368 tree decl;
369 {
370 tree parms;
374 {
379 {
382 }
385 }
387 /* Remember how many levels of template parameters we pushed so that
388 we can pop them later. */
395 }
397 /* Undo the effects of begin_member_template_processing. */
399 void
401 {
411 {
415 }
416 }
418 /* Returns non-zero iff T is a member template function. We must be
419 careful as in
421 template <class T> class C { void f(); }
423 Here, f is a template function, and a member, but not a member
424 template. This function does not concern itself with the origin of
425 T, only its present state. So if we have
427 template <class T> class C { template <class U> void f(U); }
429 then neither C<int>::f<char> nor C<T>::f<double> is considered
430 to be a member template. But, `template <class U> void
431 C<int>::f(U)' is considered a member template. */
433 int
435 tree t;
436 {
438 /* Anything that isn't a function or a template function is
439 certainly not a member template. */
442 /* A local class can't have member templates. */
447 /* If there are more levels of template parameters than
448 there are template classes surrounding the declaration,
449 then we have a member template. */
452 }
455 /* Returns non-zero iff T is a member template class. See
456 is_member_template for a description of what precisely constitutes
457 a member template. */
459 int
461 tree t;
462 {
464 /* Anything that isn't a class template, is certainly not a member
465 template. */
469 /* Anything whose context isn't a class type is surely not a
470 member template. */
473 /* If there are more levels of template parameters than there are
474 template classes surrounding the declaration, then we have a
475 member template. */
478 }
479 #endif
481 /* Return a new template argument vector which contains all of ARGS,
482 but has as its innermost set of arguments the EXTRA_ARGS. */
484 static tree
486 tree args;
487 tree extra_args;
488 {
489 tree new_args;
504 }
506 /* Like add_to_template_args, but only the outermost ARGS are added to
507 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
508 (EXTRA_ARGS) levels are added. This function is used to combine
509 the template arguments from a partial instantiation with the
510 template arguments used to attain the full instantiation from the
511 partial instantiation. */
513 static tree
515 tree args;
516 tree extra_args;
517 {
518 tree new_args;
520 /* If there are more levels of EXTRA_ARGS than there are ARGS,
521 something very fishy is going on. */
525 /* If *all* the new arguments will be the EXTRA_ARGS, just return
526 them. */
530 /* For the moment, we make ARGS look like it contains fewer levels. */
535 /* Now, we restore ARGS to its full dimensions. */
539 }
541 /* Return the N levels of innermost template arguments from the ARGS. */
543 tree
545 tree args;
547 {
548 tree new_args;
554 /* If N is 1, just return the innermost set of template arguments. */
558 /* If we're not removing anything, just return the arguments we were
559 given. */
565 /* Make a new set of arguments, not containing the outer arguments. */
572 }
574 /* We've got a template header coming up; push to a new level for storing
575 the parms. */
577 void
579 {
580 /* We use a non-tag-transparent scope here, which causes pushtag to
581 put tags in this scope, rather than in the enclosing class or
582 namespace scope. This is the right thing, since we want
583 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
584 global template class, push_template_decl handles putting the
585 TEMPLATE_DECL into top-level scope. For a nested template class,
586 e.g.:
588 template <class T> struct S1 {
589 template <class T> struct S2 {};
590 };
592 pushtag contains special code to call pushdecl_with_scope on the
593 TEMPLATE_DECL for S2. */
598 }
600 /* This routine is called when a specialization is declared. If it is
601 illegal to declare a specialization here, an error is reported. */
603 static void
605 {
608 /* [temp.expl.spec]
610 An explicit specialization shall be declared in the namespace of
611 which the template is a member, or, for member templates, in the
612 namespace of which the enclosing class or enclosing class
613 template is a member. An explicit specialization of a member
614 function, member class or static data member of a class template
615 shall be declared in the namespace of which the class template
616 is a member. */
619 scope);
621 /* [temp.expl.spec]
623 In an explicit specialization declaration for a member of a class
624 template or a member template that appears in namespace scope,
625 the member template and some of its enclosing class templates may
626 remain unspecialized, except that the declaration shall not
627 explicitly specialize a class member template if its enclosing
628 class templates are not explicitly specialized as well. */
631 }
633 /* We've just seen template <>. */
635 void
637 {
641 }
643 /* Called at then end of processing a declaration preceded by
644 template<>. */
646 void
648 {
651 }
653 /* Any template <>'s that we have seen thus far are not referring to a
654 function specialization. */
656 void
658 {
661 }
663 /* We've just seen a template header. If SPECIALIZATION is non-zero,
664 it was of the form template <>. */
666 static void
669 {
671 template_header_count++;
672 }
674 /* We're beginning an explicit instantiation. */
676 void
678 {
680 }
683 void
685 {
688 }
690 /* The TYPE is being declared. If it is a template type, that means it
691 is a partial specialization. Do appropriate error-checking. */
693 void
695 tree type;
696 {
698 {
701 {
704 {
708 }
712 }
715 }
718 }
720 /* Retrieve the specialization (in the sense of [temp.spec] - a
721 specialization is either an instantiation or an explicit
722 specialization) of TMPL for the given template ARGS. If there is
723 no such specialization, return NULL_TREE. The ARGS are a vector of
724 arguments, or a vector of vectors of arguments, in the case of
725 templates with more than one level of parameters. */
727 static tree
729 tree tmpl;
730 tree args;
731 {
732 tree s;
736 /* There should be as many levels of arguments as there are
737 levels of parameters. */
749 }
751 /* Like retrieve_specialization, but for local declarations. */
753 static tree
755 tree tmpl;
756 {
758 }
760 /* Returns non-zero iff DECL is a specialization of TMPL. */
762 int
764 tree decl;
765 tree tmpl;
766 {
767 tree t;
770 {
776 }
777 else
778 {
787 }
790 }
792 /* Register the specialization SPEC as a specialization of TMPL with
793 the indicated ARGS. Returns SPEC, or an equivalent prior
794 declaration, if available. */
796 static tree
798 tree spec;
799 tree tmpl;
800 tree args;
801 {
802 tree s;
808 /* This is the FUNCTION_DECL for a partial instantiation. Don't
809 register it; we want the corresponding TEMPLATE_DECL instead.
810 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
811 the more obvious `uses_template_parms (spec)' to avoid problems
812 with default function arguments. In particular, given
813 something like this:
815 template <class T> void f(T t1, T t = T())
817 the default argument expression is not substituted for in an
818 instantiation unless and until it is actually needed. */
821 /* There should be as many levels of arguments as there are
822 levels of parameters. */
830 {
833 /* We can sometimes try to re-register a specialization that we've
834 already got. In particular, regenerate_decl_from_template
835 calls duplicate_decls which will update the specialization
836 list. But, we'll still get called again here anyhow. It's
837 more convenient to simply allow this than to try to prevent it. */
841 {
843 {
845 {
848 {
850 fn);
852 }
853 else
854 {
855 /* This situation should occur only if the first
856 specialization is an implicit instantiation,
857 the second is an explicit specialization, and
858 the implicit instantiation has not yet been
859 used. That situation can occur if we have
860 implicitly instantiated a member function and
861 then specialized it later.
863 We can also wind up here if a friend
864 declaration that looked like an instantiation
865 turns out to be a specialization:
867 template <class T> void foo(T);
868 class S { friend void foo<>(int) };
869 template <> void foo(int);
871 We transform the existing DECL in place so that
872 any pointers to it become pointers to the
873 updated declaration.
875 If there was a definition for the template, but
876 not for the specialization, we want this to
877 look as if there is no definition, and vice
878 versa. */
883 }
884 }
886 {
889 }
890 }
891 }
892 }
898 }
900 /* Unregister the specialization SPEC as a specialization of TMPL.
901 Returns nonzero if the SPEC was listed as a specialization of
902 TMPL. */
904 static int
906 tree spec;
907 tree tmpl;
908 {
915 {
918 }
921 }
923 /* Like register_specialization, but for local declarations. We are
924 registering SPEC, an instantiation of TMPL. */
926 static void
928 tree spec;
929 tree tmpl;
930 {
935 }
937 /* Print the list of candidate FNS in an error message. */
939 void
941 tree fns;
942 {
943 tree fn;
948 {
949 tree f;
954 }
955 }
957 /* Returns the template (one of the functions given by TEMPLATE_ID)
958 which can be specialized to match the indicated DECL with the
959 explicit template args given in TEMPLATE_ID. The DECL may be
960 NULL_TREE if none is available. In that case, the functions in
961 TEMPLATE_ID are non-members.
963 If NEED_MEMBER_TEMPLATE is non-zero the function is known to be a
964 specialization of a member template.
966 The template args (those explicitly specified and those deduced)
967 are output in a newly created vector *TARGS_OUT.
969 If it is impossible to determine the result, an error message is
970 issued. The error_mark_node is returned to indicate failure. */
972 static tree
974 need_member_template)
975 tree template_id;
976 tree decl;
979 {
980 tree fns;
981 tree targs;
982 tree explicit_targs;
997 /* Check for baselinks. */
1002 {
1005 }
1008 {
1009 tree tmpl;
1014 /* DECL might be a specialization of FN. */
1017 /* FN is an ordinary member function, and we need a
1018 specialization of a member template. */
1021 /* We can get IDENTIFIER_NODEs here in certain erroneous
1022 cases. */
1025 /* This is just an ordinary non-member function. Nothing can
1026 be a specialization of that. */
1029 /* Cannot specialize functions that are created implicitly. */
1031 else
1032 {
1033 tree decl_arg_types;
1035 /* This is an ordinary member function. However, since
1036 we're here, we can assume it's enclosing class is a
1037 template class. For example,
1039 template <typename T> struct S { void f(); };
1040 template <> void S<int>::f() {}
1042 Here, S<int>::f is a non-template, but S<int> is a
1043 template class. If FN has the same type as DECL, we
1044 might be in business. */
1047 /* Its enclosing class is an explicit specialization
1048 of a template class. This is not a candidate. */
1053 /* The return types differ. */
1056 /* Adjust the type of DECL in case FN is a static member. */
1063 decl_arg_types))
1064 /* They match! */
1068 }
1070 /* See whether this function might be a specialization of this
1071 template. */
1075 /* We cannot deduce template arguments that when used to
1076 specialize TMPL will produce DECL. */
1079 /* Save this template, and the arguments deduced. */
1081 }
1084 {
1085 /* We have:
1087 [temp.expl.spec]
1089 It is possible for a specialization with a given function
1090 signature to be instantiated from more than one function
1091 template. In such cases, explicit specification of the
1092 template arguments must be used to uniquely identify the
1093 function template specialization being specialized.
1095 Note that here, there's no suggestion that we're supposed to
1096 determine which of the candidate templates is most
1097 specialized. However, we, also have:
1099 [temp.func.order]
1101 Partial ordering of overloaded function template
1102 declarations is used in the following contexts to select
1103 the function template to which a function template
1104 specialization refers:
1106 -- when an explicit specialization refers to a function
1107 template.
1109 So, we do use the partial ordering rules, at least for now.
1110 This extension can only serve to make illegal programs legal,
1111 so it's safe. And, there is strong anecdotal evidence that
1112 the committee intended the partial ordering rules to apply;
1113 the EDG front-end has that behavior, and John Spicer claims
1114 that the committee simply forgot to delete the wording in
1115 [temp.expl.spec]. */
1118 {
1121 }
1122 }
1125 {
1129 }
1133 {
1139 }
1141 /* We have one, and exactly one, match. */
1143 {
1144 /* It was a specialization of an ordinary member function in a
1145 template class. */
1148 }
1150 /* It was a specialization of a template. */
1153 {
1158 }
1159 else
1162 }
1164 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
1165 but with the default argument values filled in from those in the
1166 TMPL_TYPES. */
1168 static tree
1170 tmpl_types)
1171 tree spec_types;
1172 tree tmpl_types;
1173 {
1174 tree new_spec_types;
1182 /* Substitute into the rest of the list. */
1183 new_spec_types =
1187 /* Add the default argument for this parameter. */
1190 new_spec_types);
1191 }
1193 /* DECL is an explicit specialization. Replicate default arguments
1194 from the template it specializes. (That way, code like:
1196 template <class T> void f(T = 3);
1197 template <> void f(double);
1198 void g () { f (); }
1200 works, as required.) An alternative approach would be to look up
1201 the correct default arguments at the call-site, but this approach
1202 is consistent with how implicit instantiations are handled. */
1204 static void
1206 tree decl;
1207 {
1208 tree tmpl;
1209 tree spec_types;
1210 tree tmpl_types;
1211 tree new_spec_types;
1212 tree old_type;
1213 tree new_type;
1214 tree t;
1219 /* See if there's anything we need to do. */
1232 {
1233 /* Remove the this pointer, but remember the object's type for
1234 CV quals. */
1240 {
1241 /* DECL may contain more parameters than TMPL due to the extra
1242 in-charge parameter in constructors and destructors. */
1245 }
1247 {
1250 }
1251 }
1253 /* Compute the merged default arguments. */
1254 new_spec_types =
1257 /* Compute the new FUNCTION_TYPE. */
1259 {
1263 new_spec_types);
1266 /* Put the in-charge parameter back. */
1269 new_spec_types);
1273 new_spec_types);
1274 }
1275 else
1277 new_spec_types);
1283 }
1285 /* Check to see if the function just declared, as indicated in
1286 DECLARATOR, and in DECL, is a specialization of a function
1287 template. We may also discover that the declaration is an explicit
1288 instantiation at this point.
1290 Returns DECL, or an equivalent declaration that should be used
1291 instead if all goes well. Issues an error message if something is
1292 amiss. Returns error_mark_node if the error is not easily
1293 recoverable.
1295 FLAGS is a bitmask consisting of the following flags:
1297 2: The function has a definition.
1298 4: The function is a friend.
1300 The TEMPLATE_COUNT is the number of references to qualifying
1301 template classes that appeared in the name of the function. For
1302 example, in
1304 template <class T> struct S { void f(); };
1305 void S<int>::f();
1307 the TEMPLATE_COUNT would be 1. However, explicitly specialized
1308 classes are not counted in the TEMPLATE_COUNT, so that in
1310 template <class T> struct S {};
1311 template <> struct S<int> { void f(); }
1312 template <> void S<int>::f();
1314 the TEMPLATE_COUNT would be 0. (Note that this declaration is
1315 illegal; there should be no template <>.)
1317 If the function is a specialization, it is marked as such via
1318 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
1319 is set up correctly, and it is added to the list of specializations
1320 for that template. */
1322 tree
1324 tree declarator;
1325 tree decl;
1328 {
1336 tmpl_spec_kind tsk;
1341 {
1344 {
1347 }
1349 {
1351 /* This could be something like:
1353 template <class T> void f(T);
1354 class S { friend void f<>(int); } */
1356 else
1357 {
1358 /* This case handles bogus declarations like template <>
1359 template <class T> void f<int>(); */
1362 declarator);
1364 }
1365 }
1369 /* The error has already been reported in
1370 check_specialization_scope. */
1376 /* Fall through. */
1387 decl);
1390 /* Fall through. */
1395 else
1401 {
1403 decl);
1405 }
1410 {
1411 /* For backwards compatibility, we accept:
1413 template <class T> struct S { void f(); };
1414 void S<int>::f() {} // Missing template <>
1416 That used to be legal C++. */
1418 pedwarn
1422 }
1427 {
1428 /* This case handles bogus declarations like template <>
1429 template <class T> void f<int>(); */
1433 declarator);
1434 else
1436 declarator);
1438 }
1441 /* This is a specialization of a member template, without
1442 specialization the containing class. Something like:
1444 template <class T> struct S {
1445 template <class U> void f (U);
1446 };
1447 template <> template <class U> void S<int>::f(U) {}
1449 That's a specialization -- but of the entire template. */
1455 }
1458 {
1462 {
1463 pedwarn
1466 }
1469 }
1472 {
1476 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
1478 {
1479 tree fns;
1485 else
1488 declarator =
1490 }
1496 {
1498 /* A specialization in class scope. This is illegal,
1499 but the error will already have been flagged by
1500 check_specialization_scope. */
1502 else
1503 {
1504 /* It's not legal to write an explicit instantiation in
1505 class scope, e.g.:
1507 class C { template void f(); }
1509 This case is caught by the parser. However, on
1510 something like:
1512 template class C { void f(); };
1514 (which is illegal) we can get here. The error will be
1515 issued later. */
1516 ;
1517 }
1520 }
1522 {
1523 /* A friend declaration. We can't do much, because we don't
1524 know what this resolves to, yet. */
1529 }
1532 IDENTIFIER_NODE))
1533 {
1534 /* Find the list of functions in ctype that have the same
1535 name as the declared function. */
1542 {
1547 {
1548 /* From [temp.expl.spec]:
1550 If such an explicit specialization for the member
1551 of a class template names an implicitly-declared
1552 special member function (clause _special_), the
1553 program is ill-formed.
1555 Similar language is found in [temp.explicit]. */
1558 }
1561 }
1564 {
1568 }
1569 else
1570 {
1571 tree methods;
1573 /* For a type-conversion operator, we cannot do a
1574 name-based lookup. We might be looking for `operator
1575 int' which will be a specialization of `operator T'.
1576 So, we find *all* the conversion operators, and then
1577 select from them. */
1583 {
1587 /* There are no more conversion functions. */
1590 /* Glue all these conversion functions together
1591 with those we already have. */
1594 }
1595 }
1598 {
1602 }
1603 else
1605 }
1607 /* Figure out what exactly is being specialized at this point.
1608 Note that for an explicit instantiation, even one for a
1609 member function, we cannot tell apriori whether the
1610 instantiation is for a member template, or just a member
1611 function of a template class. Even if a member template is
1612 being instantiated, the member template arguments may be
1613 elided if they can be deduced from the rest of the
1614 declaration. */
1617 member_specialization);
1620 /* We couldn't figure out what this declaration was
1621 specializing. */
1623 else
1624 {
1628 {
1629 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
1630 is done by do_decl_instantiation later. */
1636 {
1637 /* If TMPL is not the most general template (for
1638 example, if TMPL is a friend template that is
1639 injected into namespace scope), then there will
1640 be too many levels of TARGS. Remove some of them
1641 here. */
1643 tree new_targs;
1650 }
1653 }
1655 /* If this is a specialization of a member template of a
1656 template class. In we want to return the TEMPLATE_DECL,
1657 not the specialization of it. */
1659 {
1663 }
1665 /* If we thought that the DECL was a member function, but it
1666 turns out to be specializing a static member function,
1667 make DECL a static member function as well. */
1670 {
1673 }
1675 /* Set up the DECL_TEMPLATE_INFO for DECL. */
1678 /* Inherit default function arguments from the template
1679 DECL is specializing. */
1682 /* This specialization has the same protection as the
1683 template it specializes. */
1688 /* This is not really a declaration of a specialization.
1689 It's just the name of an instantiation. But, it's not
1690 a request for an instantiation, either. */
1693 /* This is indeed a specialization. In case of constructors
1694 and destructors, we need in-charge and not-in-charge
1695 versions in V3 ABI. */
1698 /* Register this specialization so that we can find it
1699 again. */
1701 }
1702 }
1705 }
1707 /* TYPE is being declared. Verify that the use of template headers
1708 and such is reasonable. Issue error messages if not. */
1710 void
1712 tree type;
1713 {
1715 {
1716 /* We are in the scope of some `template <...>' header. */
1718 int context_depth
1723 /* This is OK; the template headers are for the context. We
1724 are actually too lenient here; like
1725 check_explicit_specialization we should consider the number
1726 of template types included in the actual declaration. For
1727 example,
1729 template <class T> struct S {
1730 template <class U> template <class V>
1731 struct I {};
1732 };
1734 is illegal, but:
1736 template <class T> struct S {
1737 template <class U> struct I;
1738 };
1740 template <class T> template <class U.
1741 struct S<T>::I {};
1743 is not. */
1744 ;
1746 /* There are two many template parameter lists. */
1748 }
1749 }
1751 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
1752 parameters. These are represented in the same format used for
1753 DECL_TEMPLATE_PARMS. */
1756 tree parms1;
1757 tree parms2;
1758 {
1759 tree p1;
1760 tree p2;
1768 {
1780 {
1791 }
1792 }
1795 /* One set of parameters has more parameters lists than the
1796 other. */
1800 }
1802 /* Complain if DECL shadows a template parameter.
1804 [temp.local]: A template-parameter shall not be redeclared within its
1805 scope (including nested scopes). */
1807 void
1809 tree decl;
1810 {
1811 tree olddecl;
1813 /* If we're not in a template, we can't possibly shadow a template
1814 parameter. */
1818 /* Figure out what we're shadowing. */
1823 /* If there's no previous binding for this name, we're not shadowing
1824 anything, let alone a template parameter. */
1828 /* If we're not shadowing a template parameter, we're done. Note
1829 that OLDDECL might be an OVERLOAD (or perhaps even an
1830 ERROR_MARK), so we can't just blithely assume it to be a _DECL
1831 node. */
1835 /* We check for decl != olddecl to avoid bogus errors for using a
1836 name inside a class. We check TPFI to avoid duplicate errors for
1837 inline member templates. */
1844 }
1846 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
1847 ORIG_LEVEL, DECL, and TYPE. */
1849 static tree
1854 tree decl;
1855 tree type;
1856 {
1865 }
1867 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
1868 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
1869 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
1870 new one is created. */
1872 static tree
1874 tree index;
1875 tree type;
1877 {
1881 {
1882 tree decl
1885 type);
1886 tree t
1896 /* Template template parameters need this. */
1899 }
1902 }
1904 /* Process information from new template parameter NEXT and append it to the
1905 LIST being built. */
1907 tree
1910 {
1911 tree parm;
1913 tree defval;
1923 {
1928 else
1931 }
1932 else
1936 {
1938 /* is a const-param */
1943 /* [temp.param]
1945 The top-level cv-qualifiers on the template-parameter are
1946 ignored when determining its type. */
1949 /* A template parameter is not modifiable. */
1956 processing_template_decl,
1958 }
1959 else
1960 {
1961 tree t;
1965 {
1967 /* This is for distinguishing between real templates and template
1968 template parameters */
1972 }
1973 else
1974 {
1976 /* parm is either IDENTIFIER_NODE or NULL_TREE */
1978 }
1985 processing_template_decl,
1987 }
1993 }
1995 /* The end of a template parameter list has been reached. Process the
1996 tree list into a parameter vector, converting each parameter into a more
1997 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
1998 as PARM_DECLs. */
2000 tree
2002 tree parms;
2003 {
2008 current_template_parms
2013 {
2017 }
2022 }
2024 /* end_template_decl is called after a template declaration is seen. */
2026 void
2028 {
2034 /* This matches the pushlevel in begin_template_parm_list. */
2039 }
2041 /* Given a template argument vector containing the template PARMS.
2042 The innermost PARMS are given first. */
2044 tree
2046 {
2047 tree header;
2052 /* If there is only one level of template parameters, we do not
2053 create a TREE_VEC of TREE_VECs. Instead, we return a single
2054 TREE_VEC containing the arguments. */
2059 {
2065 {
2068 /* T will be a list if we are called from within a
2069 begin/end_template_parm_list pair, but a vector directly
2070 if within a begin/end_member_template_processing pair. */
2072 {
2078 else
2081 }
2082 }
2086 else
2088 }
2091 }
2093 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
2094 template PARMS. Used by push_template_decl below. */
2096 static tree
2098 tree decl;
2099 tree parms;
2100 {
2105 {
2115 }
2118 }
2120 struct template_parm_data
2121 {
2122 /* The level of the template parameters we are currently
2123 processing. */
2126 /* The index of the specialization argument we are currently
2127 processing. */
2130 /* An array whose size is the number of template parameters. The
2131 elements are non-zero if the parameter has been used in any one
2132 of the arguments processed so far. */
2135 /* An array whose size is the number of template arguments. The
2136 elements are non-zero if the argument makes use of template
2137 parameters of this level. */
2139 };
2141 /* Subroutine of push_template_decl used to see if each template
2142 parameter in a partial specialization is used in the explicit
2143 argument list. If T is of the LEVEL given in DATA (which is
2144 treated as a template_parm_data*), then DATA->PARMS is marked
2145 appropriately. */
2147 static int
2149 tree t;
2151 {
2157 {
2160 }
2161 else
2162 {
2165 }
2168 {
2171 }
2173 /* Return zero so that for_each_template_parm will continue the
2174 traversal of the tree; we want to mark *every* template parm. */
2176 }
2178 /* Process the partial specialization DECL. */
2180 static tree
2182 tree decl;
2183 {
2197 /* We check that each of the template parameters given in the
2198 partial specialization is used in the argument list to the
2199 specialization. For example:
2201 template <class T> struct S;
2202 template <class T> struct S<T*>;
2204 The second declaration is OK because `T*' uses the template
2205 parameter T, whereas
2207 template <class T> struct S<int>;
2209 is no good. Even trickier is:
2211 template <class T>
2212 struct S1
2213 {
2214 template <class U>
2215 struct S2;
2216 template <class U>
2217 struct S2<T>;
2218 };
2220 The S2<T> declaration is actually illegal; it is a
2221 full-specialization. Of course,
2223 template <class U>
2224 struct S2<T (*)(U)>;
2226 or some such would have been OK. */
2234 {
2239 }
2242 {
2243 /* One of the template parms was not used in the
2244 specialization. */
2246 {
2249 }
2253 }
2255 /* [temp.class.spec]
2257 The argument list of the specialization shall not be identical to
2258 the implicit argument list of the primary template. */
2265 /* [temp.class.spec]
2267 A partially specialized non-type argument expression shall not
2268 involve template parameters of the partial specialization except
2269 when the argument expression is a simple identifier.
2271 The type of a template parameter corresponding to a specialized
2272 non-type argument shall not be dependent on a parameter of the
2273 specialization. */
2277 {
2282 /* This next line is the `argument expression is not just a
2283 simple identifier' condition and also the `specialized
2284 non-type argument' bit. */
2286 {
2289 else
2290 {
2291 /* Look at the corresponding template parameter,
2292 marking which template parameters its type depends
2293 upon. */
2294 tree type =
2296 i)));
2299 {
2300 /* We haven't yet initialized TPD2. Do so now. */
2301 tpd2.arg_uses_template_parms
2303 /* The number of parameters here is the number in the
2304 main template, which, as checked in the assertion
2305 above, is NARGS. */
2309 }
2311 /* Mark the template parameters. But this time, we're
2312 looking for the template parameters of the main
2313 template, not in the specialization. */
2322 {
2323 /* The type depended on some template parameters.
2324 If they are fully specialized in the
2325 specialization, that's OK. */
2330 {
2332 type,
2333 arg);
2335 }
2336 }
2337 }
2338 }
2339 }
2342 /* We've already got this specialization. */
2350 }
2352 /* Check that a template declaration's use of default arguments is not
2353 invalid. Here, PARMS are the template parameters. IS_PRIMARY is
2354 non-zero if DECL is the thing declared by a primary template.
2355 IS_PARTIAL is non-zero if DECL is a partial specialization. */
2357 static void
2359 tree decl;
2360 tree parms;
2363 {
2366 tree parm_level;
2368 /* [temp.param]
2370 A default template-argument shall not be specified in a
2371 function template declaration or a function template definition, nor
2372 in the template-parameter-list of the definition of a member of a
2373 class template. */
2376 /* You can't have a function template declaration in a local
2377 scope, nor you can you define a member of a class template in a
2378 local scope. */
2384 /* If this is either a friend defined in the scope of the class
2385 or a member function. */
2390 current_class_type)))
2391 /* And, if it was a member function, it really was defined in
2392 the scope of the class. */
2394 /* We already checked these parameters when the template was
2395 declared, so there's no need to do it again now. This function
2396 was defined in class scope, but we're processing it's body now
2397 that the class is complete. */
2400 /* [temp.param]
2402 If a template-parameter has a default template-argument, all
2403 subsequent template-parameters shall have a default
2404 template-argument supplied. */
2406 {
2413 {
2418 {
2420 /* For better subsequent error-recovery, we indicate that
2421 there should have been a default argument. */
2423 }
2424 }
2425 }
2428 /* For an ordinary class template, default template arguments are
2429 allowed at the innermost level, e.g.:
2430 template <class T = int>
2431 struct S {};
2432 but, in a partial specialization, they're not allowed even
2433 there, as we have in [temp.class.spec]:
2435 The template parameter list of a specialization shall not
2436 contain default template argument values.
2438 So, for a partial specialization, or for a function template,
2439 we look at all of them. */
2440 ;
2441 else
2442 /* But, for a primary class template that is not a partial
2443 specialization we look at all template parameters except the
2444 innermost ones. */
2447 /* Figure out what error message to issue. */
2452 else
2456 /* If we're inside a class definition, there's no need to
2457 examine the parameters to the class itself. On the one
2458 hand, they will be checked when the class is defined, and,
2459 on the other, default arguments are legal in things like:
2460 template <class T = double>
2461 struct S { template <class U> void f(U); };
2462 Here the default argument for `S' has no bearing on the
2463 declaration of `f'. */
2465 else
2466 /* Check everything. */
2472 {
2480 {
2482 {
2485 }
2487 /* Clear out the default argument so that we are not
2488 confused later. */
2490 }
2492 /* At this point, if we're still interested in issuing messages,
2493 they must apply to classes surrounding the object declared. */
2496 }
2497 }
2499 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
2500 parameters given by current_template_args, or reuses a
2501 previously existing one, if appropriate. Returns the DECL, or an
2502 equivalent one, if it is replaced via a call to duplicate_decls.
2504 If IS_FRIEND is non-zero, DECL is a friend declaration. */
2506 tree
2508 tree decl;
2510 {
2511 tree tmpl;
2512 tree args;
2513 tree info;
2514 tree ctx;
2519 /* See if this is a partial specialization. */
2527 /* For a friend, we want the context of the friend function, not
2528 the type of which it is a friend. */
2532 /* In the case of a virtual function, we want the class in which
2533 it is defined. */
2535 else
2536 /* Otherwise, if we're currently defining some class, the DECL
2537 is assumed to be a member of the class. */
2546 /* See if this is a primary template. */
2550 {
2561 else
2563 }
2565 /* Check to see that the rules regarding the use of default
2566 arguments are not being violated. */
2581 {
2586 /* If DECL is a TYPE_DECL for a class-template, then there won't
2587 be DECL_LANG_SPECIFIC. The information equivalent to
2588 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
2592 {
2593 /* Since a template declaration already existed for this
2594 class-type, we must be redeclaring it here. Make sure
2595 that the redeclaration is legal. */
2597 current_template_parms);
2598 /* We don't need to create a new TEMPLATE_DECL; just use the
2599 one we already had. */
2601 }
2602 else
2603 {
2609 {
2610 /* A specialization of a member template of a template
2611 class. */
2615 }
2616 }
2617 }
2618 else
2619 {
2624 {
2630 else
2631 {
2634 }
2635 }
2637 {
2640 }
2641 else
2648 {
2649 tree new_tmpl;
2651 /* The declaration is a specialization of a member
2652 template, declared outside the class. Therefore, the
2653 innermost template arguments will be NULL, so we
2654 replace them with the arguments determined by the
2655 earlier call to check_explicit_specialization. */
2658 new_tmpl
2669 args);
2671 }
2673 /* Make sure the template headers we got make sense. */
2678 {
2681 }
2682 else
2684 {
2689 {
2693 else
2697 }
2699 /* Perhaps we should also check that the parms are used in the
2700 appropriate qualifying scopes in the declarator? */
2704 else
2706 }
2707 }
2712 /* Push template declarations for global functions and types. Note
2713 that we do not try to push a global template friend declared in a
2714 template class; such a thing may well depend on the template
2715 parameters of the class. */
2726 {
2730 /* Don't change the name if we've already set it up. */
2733 }
2738 }
2740 tree
2742 tree decl;
2743 {
2745 }
2747 /* Called when a class template TYPE is redeclared with the indicated
2748 template PARMS, e.g.:
2750 template <class T> struct S;
2751 template <class T> struct S {}; */
2753 void
2755 tree type;
2756 tree parms;
2757 {
2758 tree tmpl;
2759 tree tmpl_parms;
2763 {
2766 }
2770 /* The type is nested in some template class. Nothing to worry
2771 about here; there are no new template parameters for the nested
2772 type. */
2779 {
2786 }
2789 {
2796 {
2800 }
2803 {
2804 /* We have in [temp.param]:
2806 A template-parameter may not be given default arguments
2807 by two different declarations in the same scope. */
2811 }
2814 /* Update the previous template parameters (which are the ones
2815 that will really count) with the new default value. */
2818 /* Update the new parameters, too; they'll be used as the
2819 parameters for any members. */
2821 }
2822 }
2824 /* Attempt to convert the non-type template parameter EXPR to the
2825 indicated TYPE. If the conversion is successful, return the
2826 converted value. If the conversion is unsuccessful, return
2827 NULL_TREE if we issued an error message, or error_mark_node if we
2828 did not. We issue error messages for out-and-out bad template
2829 parameters, but not simply because the conversion failed, since we
2830 might be just trying to do argument deduction. By the time this
2831 function is called, neither TYPE nor EXPR may make use of template
2832 parameters. */
2834 static tree
2836 tree type;
2837 tree expr;
2838 {
2841 /* A template-argument for a non-type, non-template
2842 template-parameter shall be one of:
2844 --an integral constant-expression of integral or enumeration
2845 type; or
2847 --the name of a non-type template-parameter; or
2849 --the name of an object or function with external linkage,
2850 including function templates and function template-ids but
2851 excluding non-static class members, expressed as id-expression;
2852 or
2854 --the address of an object or function with external linkage,
2855 including function templates and function template-ids but
2856 excluding non-static class members, expressed as & id-expression
2857 where the & is optional if the name refers to a function or
2858 array; or
2860 --a pointer to member expressed as described in _expr.unary.op_. */
2862 /* An integral constant-expression can include const variables or
2863 enumerators. Simplify things by folding them to their values,
2864 unless we're about to bind the declaration to a reference
2865 parameter. */
2871 /* OK for now. We'll check that it has external linkage later.
2872 Check this first since if expr_type is the unknown_type_node
2873 we would otherwise complain below. */
2874 ;
2877 {
2880 }
2885 /* If expr is the address of an overloaded function, we
2886 will get the unknown_type_node at this point. */
2888 {
2889 tree referent;
2897 else
2898 {
2900 {
2901 bad_argument:
2904 {
2907 else
2909 }
2915 }
2919 }
2922 {
2923 error ("string literal %E is not a valid template argument because it is the address of an object with static linkage",
2924 referent);
2926 }
2929 /* We'll check that it has external linkage later. */
2930 ;
2934 {
2937 }
2938 }
2942 {
2944 {
2945 non_constant:
2947 expr);
2949 }
2950 }
2951 else
2952 {
2955 }
2958 {
2962 /* For a non-type template-parameter of integral or enumeration
2963 type, integral promotions (_conv.prom_) and integral
2964 conversions (_conv.integral_) are applied. */
2968 /* It's safe to call digest_init in this case; we know we're
2969 just converting one integral constant expression to another. */
2973 /* Curiously, some TREE_CONSTANT integral expressions do not
2974 simplify to integer constants. For example, `3 % 0',
2975 remains a TRUNC_MOD_EXPR. */
2981 {
2985 {
2986 tree e;
2988 /* For a non-type template-parameter of type pointer to data
2989 member, qualification conversions (_conv.qual_) are
2990 applied. */
2993 /* The call to perform_qualification_conversions will
2994 insert a NOP_EXPR over EXPR to do express conversion,
2995 if necessary. But, that will confuse us if we use
2996 this (converted) template parameter to instantiate
2997 another template; then the thing will not look like a
2998 valid template argument. So, just make a new
2999 constant, of the appropriate type. */
3002 }
3004 {
3005 /* For a non-type template-parameter of type pointer to
3006 function, only the function-to-pointer conversion
3007 (_conv.func_) is applied. If the template-argument
3008 represents a set of overloaded functions (or a pointer to
3009 such), the matching function is selected from the set
3010 (_over.over_). */
3011 tree fns;
3012 tree fn;
3016 else
3025 {
3028 else
3030 }
3037 }
3038 else
3039 {
3040 /* For a non-type template-parameter of type pointer to
3041 object, qualification conversions (_conv.qual_) and the
3042 array-to-pointer conversion (_conv.array_) are applied.
3043 [Note: In particular, neither the null pointer conversion
3044 (_conv.ptr_) nor the derived-to-base conversion
3045 (_conv.ptr_) are applied. Although 0 is a valid
3046 template-argument for a non-type template-parameter of
3047 integral type, it is not a valid template-argument for a
3048 non-type template-parameter of pointer type.]
3050 The call to decay_conversion performs the
3051 array-to-pointer conversion, if appropriate. */
3056 else
3058 }
3059 }
3063 {
3066 /* If this expression already has reference type, get the
3067 underling object. */
3069 {
3073 }
3076 {
3077 /* For a non-type template-parameter of type reference to
3078 function, no conversions apply. If the
3079 template-argument represents a set of overloaded
3080 functions, the matching function is selected from the
3081 set (_over.over_). */
3082 tree fn;
3090 {
3092 /* Don't issue an error here; we might get a different
3093 function if the overloading had worked out
3094 differently. */
3096 else
3098 }
3105 }
3106 else
3107 {
3108 /* For a non-type template-parameter of type reference to
3109 object, no conversions apply. The type referred to by the
3110 reference may be more cv-qualified than the (otherwise
3111 identical) type of the template-argument. The
3112 template-parameter is bound directly to the
3113 template-argument, which must be an lvalue. */
3117 expr_type)
3120 }
3124 }
3128 {
3131 /* For a non-type template-parameter of type pointer to member
3132 function, no conversions apply. If the template-argument
3133 represents a set of overloaded member functions, the
3134 matching member function is selected from the set
3135 (_over.over_). */
3142 {
3143 /* A ptr-to-member constant. */
3146 else
3148 }
3161 }
3165 /* All non-type parameters must have one of these types. */
3168 }
3171 }
3173 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
3174 template template parameters. Both PARM_PARMS and ARG_PARMS are
3175 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
3176 or PARM_DECL.
3178 ARG_PARMS may contain more parameters than PARM_PARMS. If this is
3179 the case, then extra parameters must have default arguments.
3181 Consider the example:
3182 template <class T, class Allocator = allocator> class vector;
3183 template<template <class U> class TT> class C;
3185 C<vector> is a valid instantiation. PARM_PARMS for the above code
3186 contains a TYPE_DECL (for U), ARG_PARMS contains two TYPE_DECLs (for
3187 T and Allocator) and OUTER_ARGS contains the argument that is used to
3188 substitute the TT parameter. */
3190 static int
3194 tsubst_flags_t complain;
3196 {
3206 /* The rule here is opposite of coerce_template_parms. */
3213 {
3225 {
3230 /* We encounter instantiations of templates like
3231 template <template <template <class> class> class TT>
3232 class C; */
3233 {
3239 outer_args))
3241 }
3245 /* The tsubst call is used to handle cases such as
3246 template <class T, template <T> class TT> class D;
3247 i.e. the parameter list of TT depends on earlier parameters. */
3256 }
3257 }
3259 }
3261 /* Convert the indicated template ARG as necessary to match the
3262 indicated template PARM. Returns the converted ARG, or
3263 error_mark_node if the conversion was unsuccessful. Error and
3264 warning messages are issued under control of COMPLAIN. This
3265 conversion is for the Ith parameter in the parameter list. ARGS is
3266 the full set of template arguments deduced so far. */
3268 static tree
3270 tree parm;
3271 tree arg;
3272 tree args;
3273 tsubst_flags_t complain;
3275 tree in_decl;
3276 {
3277 tree val;
3278 tree inner_args;
3286 {
3287 /* The template argument was the name of some
3288 member function. That's usually
3289 illegal, but static members are OK. In any
3290 case, grab the underlying fields/functions
3291 and issue an error later if required. */
3294 }
3307 {
3309 /* This is a template name used within the scope of the
3310 template. It could be the template, or it could be the
3311 instantiation. Choose whichever makes sense. */
3313 else
3315 }
3316 else
3317 /* It is a non-template class, or a specialization of a template
3318 class, or a non-template member of a template class. */
3332 {
3341 }
3343 {
3345 {
3347 {
3354 else
3356 }
3357 }
3359 }
3361 {
3363 {
3368 else
3370 }
3372 }
3375 {
3377 {
3379 /* The number of argument required is not known yet.
3380 Just accept it for now. */
3382 else
3383 {
3389 inner_args))
3390 {
3393 /* TEMPLATE_TEMPLATE_PARM node is preferred over
3394 TEMPLATE_DECL. */
3398 }
3399 else
3400 {
3402 {
3406 }
3409 }
3410 }
3411 }
3412 else
3413 {
3416 {
3417 /* [basic.link]: A name with no linkage (notably, the
3418 name of a class or enumeration declared in a local
3419 scope) shall not be used to declare an entity with
3420 linkage. This implies that names with no linkage
3421 cannot be used as template arguments. */
3424 {
3426 pedwarn
3428 else
3429 error
3433 }
3434 }
3435 }
3436 }
3437 else
3438 {
3448 /* We used to call digest_init here. However, digest_init
3449 will report errors, which we don't want when complain
3450 is zero. More importantly, digest_init will try too
3451 hard to convert things: for example, `0' should not be
3452 converted to pointer type at this point according to
3453 the standard. Accepting this is not merely an
3454 extension, since deciding whether or not these
3455 conversions can occur is part of determining which
3456 function template to call, or whether a given explicit
3457 argument specification is legal. */
3459 else
3467 }
3470 }
3472 /* Convert all template arguments to their appropriate types, and
3473 return a vector containing the innermost resulting template
3474 arguments. If any error occurs, return error_mark_node. Error and
3475 warning messages are issued under control of COMPLAIN. Some error
3476 messages are issued even if COMPLAIN is zero; for instance, if a
3477 template argument is composed from a local class.
3479 If REQUIRE_ALL_ARGUMENTS is non-zero, all arguments must be
3480 provided in ARGLIST, or else trailing parameters must have default
3481 values. If REQUIRE_ALL_ARGUMENTS is zero, we will attempt argument
3482 deduction for any unspecified trailing arguments. */
3484 static tree
3486 complain,
3487 require_all_arguments)
3489 tree in_decl;
3490 tsubst_flags_t complain;
3492 {
3494 tree inner_args;
3495 tree new_args;
3496 tree new_inner_args;
3504 && require_all_arguments
3506 {
3508 {
3514 }
3517 }
3522 {
3523 tree arg;
3524 tree parm;
3526 /* Get the Ith template parameter. */
3529 /* Calculate the Ith argument. */
3531 {
3534 }
3537 /* If no template argument was supplied, look for a default
3538 value. */
3540 {
3541 /* There was no default value. */
3544 }
3547 else
3549 in_decl);
3551 /* Now, convert the Ith argument, as necessary. */
3553 /* We're out of arguments. */
3554 {
3557 }
3559 {
3562 }
3563 else
3566 in_decl);
3569 lost++;
3571 }
3577 }
3579 /* Returns 1 if template args OT and NT are equivalent. */
3581 static int
3584 {
3589 /* For member templates */
3595 else
3597 }
3599 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
3600 of template arguments. Returns 0 otherwise. */
3602 int
3605 {
3612 {
3618 }
3620 }
3622 /* Given class template name and parameter list, produce a user-friendly name
3623 for the instantiation. */
3629 {
3636 else
3640 #define ccat(C) obstack_1grow (&scratch_obstack, (C));
3641 #define cat(S) obstack_grow (&scratch_obstack, (S), strlen (S))
3649 {
3657 {
3660 }
3662 {
3664 {
3665 /* Already substituted with real template. Just output
3666 the template name here */
3669 {
3670 /* The template may be defined in a namespace, or
3671 may be a member template. */
3677 }
3679 }
3680 else
3681 /* Output the parameter declaration */
3684 }
3685 else
3689 {
3690 /* New list cell was built because old chain link was in
3691 use. */
3694 }
3695 /* No need to check arglist against parmlist here; we did that
3696 in coerce_template_parms, called from lookup_template_class. */
3698 }
3699 {
3703 offset--;
3706 /* B<C<char> >, not B<C<char>> */
3709 }
3713 }
3715 static tree
3717 tree t;
3718 {
3720 /* Specializations have already had their names set up in
3721 lookup_template_class. */
3723 {
3726 /* For non-primary templates, the template parameters are
3727 implicit from their surrounding context. */
3729 {
3738 }
3739 }
3742 }
3744 static void
3746 tree d;
3747 {
3751 tree pt;
3757 /* We are called both from instantiate_decl, where we've already had a
3758 tinst_level pushed, and instantiate_template, where we haven't.
3759 Compensate. */
3768 else
3777 }
3780 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS (which
3781 may be either a _DECL or an overloaded function or an
3782 IDENTIFIER_NODE), and ARGLIST. */
3784 tree
3787 {
3788 tree type;
3791 {
3794 }
3802 else
3804 }
3806 /* Within the scope of a template class S<T>, the name S gets bound
3807 (in build_self_reference) to a TYPE_DECL for the class, not a
3808 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
3809 or one of its enclosing classes, and that type is a template,
3810 return the associated TEMPLATE_DECL. Otherwise, the original
3811 DECL is returned. */
3813 static tree
3815 tree decl;
3816 {
3823 }
3825 /* Given an IDENTIFIER_NODE (type TEMPLATE_DECL) and a chain of
3826 parameters, find the desired type.
3828 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
3829 (Actually ARGLIST may be either a TREE_LIST or a TREE_VEC. It will
3830 be a TREE_LIST if called directly from the parser, and a TREE_VEC
3831 otherwise.)
3833 IN_DECL, if non-NULL, is the template declaration we are trying to
3834 instantiate.
3836 If ENTERING_SCOPE is non-zero, we are about to enter the scope of
3837 the class we are looking up.
3839 Issue error and warning messages under control of COMPLAIN.
3841 If the template class is really a local class in a template
3842 function, then the FUNCTION_CONTEXT is the function in which it is
3843 being instantiated. */
3845 tree
3848 tree in_decl;
3849 tree context;
3851 tsubst_flags_t complain;
3852 {
3854 tree t;
3857 {
3861 else
3862 {
3869 }
3872 }
3874 {
3877 /* If we are declaring a constructor, say A<T>::A<T>, we will get
3878 an implicit typename for the second A. Deal with it. */
3883 {
3886 }
3887 }
3890 {
3893 }
3896 {
3900 }
3902 /* With something like `template <class T> class X class X { ... };'
3903 we could end up with D1 having nothing but an IDENTIFIER_VALUE.
3904 We don't want to do that, but we have to deal with the situation,
3905 so let's give them some syntax errors to chew on instead of a
3906 crash. Alternatively D1 might not be a template type at all. */
3908 {
3912 }
3915 /* If we're called from the parser, make sure it's a user visible
3916 template. */
3920 {
3922 {
3926 }
3928 }
3931 {
3932 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
3933 template arguments */
3935 tree parm;
3936 tree arglist2;
3940 /* Consider an example where a template template parameter declared as
3942 template <class T, class U = std::allocator<T> > class TT
3944 The template parameter level of T and U are one level larger than
3945 of TT. To proper process the default argument of U, say when an
3946 instantiation `TT<int>' is seen, we need to build the full
3947 arguments containing {int} as the innermost level. Outer levels
3948 can be obtained from `current_template_args ()'. */
3960 }
3961 else
3962 {
3964 tree gen_tmpl;
3965 tree type_decl;
3978 {
3979 /* We've been given an incomplete set of template arguments.
3980 For example, given:
3982 template <class T> struct S1 {
3983 template <class U> struct S2 {};
3984 template <class U> struct S2<U*> {};
3985 };
3987 we will be called with an ARGLIST of `U*', but the
3988 TEMPLATE will be `template <class T> template
3989 <class U> struct S1<T>::S2'. We must fill in the missing
3990 arguments. */
3991 arglist
3993 arglist);
3995 }
3997 /* Now we should have enough arguments. */
4000 /* From here on, we're only interested in the most general
4001 template. */
4004 /* Calculate the BOUND_ARGS. These will be the args that are
4005 actually tsubst'd into the definition to create the
4006 instantiation. */
4008 {
4009 /* We have multiple levels of arguments to coerce, at once. */
4019 {
4025 /* We temporarily reduce the length of the ARGLIST so
4026 that coerce_template_parms will see only the arguments
4027 corresponding to the template parameters it is
4028 examining. */
4030 }
4032 /* Restore the ARGLIST to its full size. */
4036 }
4037 else
4038 arglist
4045 /* We were unable to bind the arguments. */
4048 /* In the scope of a template class, explicit references to the
4049 template class refer to the type of the template, not any
4050 instantiation of it. For example, in:
4052 template <class T> class C { void f(C<T>); }
4054 the `C<T>' is just the same as `C'. Outside of the
4055 class, however, such a reference is an instantiation. */
4057 arglist))
4058 {
4062 {
4063 tree ctx;
4065 /* Note that we use DECL_CONTEXT, rather than
4066 CP_DECL_CONTEXT, so that the termination test is
4067 always just `ctx'. We're not interested in namespace
4068 scopes. */
4070 ctx;
4076 /* We're not in the scope of the class, so the
4077 TEMPLATE_TYPE is not the type we want after
4078 all. */
4080 }
4081 }
4089 {
4092 /* Use the move-to-front heuristic to speed up future
4093 searches. */
4100 }
4102 /* This type is a "partial instantiation" if any of the template
4103 arguments still involve template parameters. Note that we set
4104 IS_PARTIAL_INSTANTIATION for partial specializations as
4105 well. */
4111 {
4116 }
4123 /* Create the type. */
4125 {
4127 {
4130 }
4131 else
4132 /* We don't want to call start_enum for this type, since
4133 the values for the enumeration constants may involve
4134 template parameters. And, no one should be interested
4135 in the enumeration constants for such a type. */
4137 }
4138 else
4139 {
4147 /* A local class. Make sure the decl gets registered properly. */
4150 }
4152 /* If we called start_enum or pushtag above, this information
4153 will already be set up. */
4155 {
4165 }
4166 else
4169 /* Set up the template information. We have to figure out which
4170 template is the immediate parent if this is a full
4171 instantiation. */
4174 /* This case is easy; there are no member templates involved. */
4176 else
4177 {
4178 /* This is a full instantiation of a member template. Look
4179 for a partial instantiation of which this is an instance. */
4183 {
4187 /* We only want partial instantiations, here, not
4188 specializations or full instantiations. */
4193 /* Temporarily reduce by one the number of levels in the
4194 ARGLIST and in FOUND so as to avoid comparing the
4195 last set of arguments. */
4199 /* See if the arguments match. If they do, then TMPL is
4200 the partial instantiation we want. */
4203 /* Restore the argument vectors to their full size. */
4208 {
4211 }
4212 }
4215 {
4216 /* There was no partial instantiation. This happens
4217 where C<T> is a member template of A<T> and it's used
4218 in something like
4220 template <typename T> struct B { A<T>::C<int> m; };
4221 B<float>;
4223 Create the partial instantiation.
4224 */
4228 }
4229 }
4238 /* Now that the type has been registered on the instantiations
4239 list, we set up the enumerators. Because the enumeration
4240 constants may involve the enumeration type itself, we make
4241 sure to register the type first, and then create the
4242 constants. That way, doing tsubst_expr for the enumeration
4243 constants won't result in recursive calls here; we'll find
4244 the instantiation and exit above. */
4247 /* Reset the name of the type, now that CLASSTYPE_TEMPLATE_INFO
4248 is set up. */
4252 {
4253 /* For backwards compatibility; code that uses
4254 -fexternal-templates expects looking up a template to
4255 instantiate it. I think DDD still relies on this.
4256 (jason 8/20/1998) */
4258 && flag_external_templates
4262 }
4263 else
4264 /* If the type makes use of template parameters, the
4265 code that generates debugging information will crash. */
4269 }
4270 }
4271 \f
4272 struct pair_fn_data
4273 {
4274 tree_fn_t fn;
4276 };
4278 /* Called from for_each_template_parm via walk_tree. */
4280 static tree
4285 {
4296 {
4300 /* Fall through. */
4312 /* Since we're not going to walk subtrees, we have to do this
4313 explicitly here. */
4316 /* Fall through. */
4319 /* Check the return type. */
4323 /* Check the parameter types. Since default arguments are not
4324 instantiated until they are needed, the TYPE_ARG_TYPES may
4325 contain expressions that involve template parameters. But,
4326 no-one should be looking at them yet. And, once they're
4327 instantiated, they don't contain template parameters, so
4328 there's no point in looking at them then, either. */
4329 {
4330 tree parm;
4336 /* Since we've already handled the TYPE_ARG_TYPES, we don't
4337 want walk_tree walking into them itself. */
4339 }
4347 /* Fall through. */
4357 /* Record template parameters such as `T' inside `TT<T>'. */
4360 /* Fall through. */
4372 /* A template template parameter is encountered */
4377 /* Already substituted template template parameter */
4395 /* If there's no type, then this thing must be some expression
4396 involving template parameters. */
4418 }
4420 /* We didn't find any template parameters we liked. */
4422 }
4424 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
4425 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
4426 call FN with the parameter and the DATA.
4427 If FN returns non-zero, the iteration is terminated, and
4428 for_each_template_parm returns 1. Otherwise, the iteration
4429 continues. If FN never returns a non-zero value, the value
4430 returned by for_each_template_parm is 0. If FN is NULL, it is
4431 considered to be the function which always returns 1. */
4433 static int
4435 tree t;
4436 tree_fn_t fn;
4438 {
4441 /* Set up. */
4445 /* Walk the tree. (Conceptually, we would like to walk without
4446 duplicates, but for_each_template_parm_r recursively calls
4447 for_each_template_parm, so we would need to reorganize a fair
4448 bit to use walk_tree_without_duplicates.) */
4450 for_each_template_parm_r,
4453 }
4455 int
4457 tree t;
4458 {
4460 }
4464 #ifdef GATHER_STATISTICS
4466 #endif
4470 /* We're starting to instantiate D; record the template instantiation context
4471 for diagnostics and to restore it later. */
4473 int
4475 tree d;
4476 {
4480 {
4481 /* If the instantiation in question still has unbound template parms,
4482 we don't really care if we can't instantiate it, so just return.
4483 This happens with base instantiation for implicit `typename'. */
4488 error ("template instantiation depth exceeds maximum of %d (use -ftemplate-depth-NN to increase the maximum) instantiating `%D'",
4494 }
4501 #ifdef GATHER_STATISTICS
4504 #endif
4508 }
4510 /* We're done instantiating this template; return to the instantiation
4511 context. */
4513 void
4515 {
4518 /* Restore the filename and line number stashed away when we started
4519 this instantiation. */
4527 }
4529 /* We're instantiating a deferred template; restore the template
4530 instantiation context in which the instantiation was requested, which
4531 is one step out from LEVEL. */
4533 static void
4535 tree level;
4536 {
4537 tree t;
4545 }
4547 /* Return the outermost template instantiation context, for use with
4548 -falt-external-templates. */
4550 tree
4552 {
4557 ;
4559 }
4561 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
4562 vector of template arguments, as for tsubst.
4564 Returns an appropriate tsubst'd friend declaration. */
4566 static tree
4568 tree decl;
4569 tree args;
4570 {
4571 tree new_friend;
4581 /* This was a friend declared with an explicit template
4582 argument list, e.g.:
4584 friend void f<>(T);
4586 to indicate that f was a template instantiation, not a new
4587 function declaration. Now, we have to figure out what
4588 instantiation of what template. */
4589 {
4591 tree new_args;
4592 tree tmpl;
4595 /* Friend functions are looked up in the containing namespace scope.
4596 We must enter that scope, to avoid finding member functions of the
4597 current cless with same name. */
4612 }
4616 /* The NEW_FRIEND will look like an instantiation, to the
4617 compiler, but is not an instantiation from the point of view of
4618 the language. For example, we might have had:
4620 template <class T> struct S {
4621 template <class U> friend void f(T, U);
4622 };
4624 Then, in S<int>, template <class U> void f(int, U) is not an
4625 instantiation of anything. */
4628 {
4632 }
4634 /* The mangled name for the NEW_FRIEND is incorrect. The function
4635 is not a template instantiation and should not be mangled like
4636 one. Therefore, we forget the mangling here; we'll recompute it
4637 later if we need it. */
4639 {
4642 }
4645 {
4646 tree old_decl;
4647 tree new_friend_template_info;
4648 tree new_friend_result_template_info;
4649 tree ns;
4652 /* We must save some information from NEW_FRIEND before calling
4653 duplicate decls since that function will free NEW_FRIEND if
4654 possible. */
4657 {
4658 /* This declaration is a `primary' template. */
4661 new_friend_is_defn
4663 new_friend_result_template_info
4665 }
4666 else
4667 {
4670 }
4672 /* Inside pushdecl_namespace_level, we will push into the
4673 current namespace. However, the friend function should go
4674 into the namespace of the template. */
4681 {
4682 /* This new friend declaration matched an existing
4683 declaration. For example, given:
4685 template <class T> void f(T);
4686 template <class U> class C {
4687 template <class T> friend void f(T) {}
4688 };
4690 the friend declaration actually provides the definition
4691 of `f', once C has been instantiated for some type. So,
4692 old_decl will be the out-of-class template declaration,
4693 while new_friend is the in-class definition.
4695 But, if `f' was called before this point, the
4696 instantiation of `f' will have DECL_TI_ARGS corresponding
4697 to `T' but not to `U', references to which might appear
4698 in the definition of `f'. Previously, the most general
4699 template for an instantiation of `f' was the out-of-class
4700 version; now it is the in-class version. Therefore, we
4701 run through all specialization of `f', adding to their
4702 DECL_TI_ARGS appropriately. In particular, they need a
4703 new set of outer arguments, corresponding to the
4704 arguments for this class instantiation.
4706 The same situation can arise with something like this:
4708 friend void f(int);
4709 template <class T> class C {
4710 friend void f(T) {}
4711 };
4713 when `C<int>' is instantiated. Now, `f(int)' is defined
4714 in the class. */
4717 /* On the other hand, if the in-class declaration does
4718 *not* provide a definition, then we don't want to alter
4719 existing definitions. We can just leave everything
4720 alone. */
4721 ;
4722 else
4723 {
4724 /* Overwrite whatever template info was there before, if
4725 any, with the new template information pertaining to
4726 the declaration. */
4730 /* duplicate_decls will take care of this case. */
4731 ;
4732 else
4733 {
4734 tree t;
4735 tree new_friend_args;
4744 {
4750 }
4752 /* Now, since specializations are always supposed to
4753 hang off of the most general template, we must move
4754 them. */
4757 {
4762 }
4763 }
4764 }
4766 /* The information from NEW_FRIEND has been merged into OLD_DECL
4767 by duplicate_decls. */
4769 }
4770 }
4772 {
4773 /* Check to see that the declaration is really present, and,
4774 possibly obtain an improved declaration. */
4776 new_friend);
4780 }
4782 done:
4786 }
4788 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
4789 template arguments, as for tsubst.
4791 Returns an appropriate tsubst'd friend type or error_mark_node on
4792 failure. */
4794 static tree
4796 tree friend_tmpl;
4797 tree args;
4798 {
4799 tree friend_type;
4800 tree tmpl;
4802 /* First, we look for a class template. */
4805 /* But, if we don't find one, it might be because we're in a
4806 situation like this:
4808 template <class T>
4809 struct S {
4810 template <class U>
4811 friend struct S;
4812 };
4814 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
4815 for `S<int>', not the TEMPLATE_DECL. */
4817 {
4820 }
4823 {
4824 /* The friend template has already been declared. Just
4825 check to see that the declarations match, and install any new
4826 default parameters. We must tsubst the default parameters,
4827 of course. We only need the innermost template parameters
4828 because that is all that redeclare_class_template will look
4829 at. */
4830 tree parms
4837 }
4838 else
4839 {
4840 /* The friend template has not already been declared. In this
4841 case, the instantiation of the template class will cause the
4842 injection of this template into the global scope. */
4845 /* The new TMPL is not an instantiation of anything, so we
4846 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
4847 the new type because that is supposed to be the corresponding
4848 template decl, i.e., TMPL. */
4853 /* Inject this template into the global scope. */
4855 }
4858 }
4860 tree
4862 tree type;
4863 {
4865 tree typedecl;
4873 /* Figure out which template is being instantiated. */
4877 /* Figure out which arguments are being used to do the
4878 instantiation. */
4883 /* If this is a partial instantiation, then we can't instantiate
4884 the type; there's no telling whether or not one of the
4885 template parameters might eventually be instantiated to some
4886 value that results in a specialization being used. For
4887 example, consider:
4889 template <class T>
4890 struct S {};
4892 template <class U>
4893 void f(S<U>);
4895 template <>
4896 struct S<int> {};
4898 Now, the `S<U>' in `f<int>' is the specialization, not an
4899 instantiation of the original template. */
4902 /* Determine what specialization of the original template to
4903 instantiate. */
4905 /* There's no telling which specialization is appropriate at this
4906 point. Since all peeking at the innards of this partial
4907 instantiation are extensions (like the "implicit typename"
4908 extension, which allows users to omit the keyword `typename' on
4909 names that are declared as types in template base classes), we
4910 are free to do what we please.
4912 Trying to figure out which partial instantiation to use can
4913 cause a crash. (Some of the template arguments don't even have
4914 types.) So, we just use the most general version. */
4916 else
4917 {
4921 {
4926 {
4928 args))
4929 {
4932 }
4933 }
4936 }
4937 }
4941 else
4944 /* If the template we're instantiating is incomplete, then clearly
4945 there's nothing we can do. */
4949 /* If this is a partial instantiation, don't tsubst anything. We will
4950 only use this type for implicit typename, so the actual contents don't
4951 matter. All that matters is whether a particular name is a type. */
4953 {
4954 /* The fields set here must be kept in sync with those cleared
4955 in begin_class_definition. */
4962 /* Pretend that the type is complete, so that we will look
4963 inside it during name lookup and such. */
4966 }
4968 /* If we've recursively instantiated too many templates, stop. */
4972 /* Now we're really doing the instantiation. Mark the type as in
4973 the process of being defined. */
4979 {
4980 /* This TYPE is actually a instantiation of of a partial
4981 specialization. We replace the innermost set of ARGS with
4982 the arguments appropriate for substitution. For example,
4983 given:
4985 template <class T> struct S {};
4986 template <class T> struct S<T*> {};
4988 and supposing that we are instantiating S<int*>, ARGS will
4989 present be {int*} but we need {int}. */
4990 tree inner_args
4992 args);
4994 /* If there were multiple levels in ARGS, replacing the
4995 innermost level would alter CLASSTYPE_TI_ARGS, which we don't
4996 want, so we make a copy first. */
4998 {
5001 }
5002 else
5004 }
5007 {
5009 {
5012 }
5013 else
5014 {
5016 SET_CLASSTYPE_INTERFACE_UNKNOWN_X
5018 }
5019 }
5020 else
5021 {
5023 }
5054 {
5059 /* Substitute into each of the bases to determine the actual
5060 basetypes. */
5062 {
5063 tree base;
5064 tree access;
5065 tree pbase;
5069 /* Substitute to figure out the base class. */
5074 /* Calculate the correct access node. */
5076 {
5081 else
5083 }
5084 else
5085 {
5090 else
5092 }
5095 }
5097 /* The list is now in reverse order; correct that. */
5100 /* Now call xref_basetypes to set up all the base-class
5101 information. */
5107 type,
5108 base_list);
5109 }
5111 /* Now that our base classes are set up, enter the scope of the
5112 class, so that name lookups into base classes, etc. will work
5113 correctly. This is precisely analogous to what we do in
5114 begin_class_definition when defining an ordinary non-template
5115 class. */
5119 {
5122 tree newtag;
5127 {
5129 /* Unfortunately, lookup_template_class sets
5130 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
5131 instantiation (i.e., for the type of a member template
5132 class nested within a template class.) This behavior is
5133 required for maybe_process_partial_specialization to work
5134 correctly, but is not accurate in this case; the TAG is not
5135 an instantiation of anything. (The corresponding
5136 TEMPLATE_DECL is an instantiation, but the TYPE is not.) */
5139 /* Now, we call pushtag to put this NEWTAG into the scope of
5140 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
5141 pushtag calling push_template_decl. We don't have to do
5142 this for enums because it will already have been done in
5143 tsubst_enum. */
5147 }
5148 }
5150 /* Don't replace enum constants here. */
5153 {
5154 tree r;
5156 /* The the file and line for this declaration, to assist in
5157 error message reporting. Since we called push_tinst_level
5158 above, we don't need to restore these. */
5164 {
5165 tree init;
5170 else
5179 }
5181 /* R will have a TREE_CHAIN if and only if it has already been
5182 processed by finish_member_declaration. This can happen
5183 if, for example, it is a TYPE_DECL for a class-scoped
5184 ENUMERAL_TYPE; such a thing will already have been added to
5185 the field list by tsubst_enum above. */
5187 {
5190 }
5191 }
5193 /* Set up the list (TYPE_METHODS) and vector (CLASSTYPE_METHOD_VEC)
5194 for this instantiation. */
5196 {
5201 }
5203 /* Construct the DECL_FRIENDLIST for the new class type. */
5208 {
5209 tree friends;
5217 args));
5218 else
5220 }
5225 {
5227 tree new_friend_type;
5234 else
5235 {
5238 /* The call to xref_tag_from_type does injection for friend
5239 classes. */
5241 new_friend_type =
5244 }
5247 /* Trick make_friend_class into realizing that the friend
5248 we're adding is a template, not an ordinary class. It's
5249 important that we use make_friend_class since it will
5250 perform some error-checking and output cross-reference
5251 information. */
5259 }
5263 {
5266 }
5268 /* Set the file and line number information to whatever is given for
5269 the class itself. This puts error messages involving generated
5270 implicit functions at a predictable point, and the same point
5271 that would be used for non-template classes. */
5279 /* Clear this now so repo_template_used is happy. */
5283 /* Now that the class is complete, instantiate default arguments for
5284 any member functions. We don't do this earlier because the
5285 default arguments may reference members of the class. */
5289 /* Implicitly generated member functions will not have template
5290 information; they are not instantiations, but instead are
5291 created "fresh" for each instantiation. */
5300 }
5302 static int
5305 {
5310 /* Don't care if one declares its arg const and the other doesn't -- the
5311 main variant of the arg type is all that matters. */
5316 }
5318 /* If arg is a non-type template parameter that does not depend on template
5319 arguments, fold it like we weren't in the body of a template. */
5321 static tree
5323 tree arg;
5324 {
5326 {
5327 /* Sometimes, one of the args was an expression involving a
5328 template constant parameter, like N - 1. Now that we've
5329 tsubst'd, we might have something like 2 - 1. This will
5330 confuse lookup_template_class, so we do constant folding
5331 here. We have to unset processing_template_decl, to
5332 fool build_expr_from_tree() into building an actual
5333 tree. */
5335 /* If the TREE_TYPE of ARG is not NULL_TREE, ARG is already
5336 as simple as it's going to get, and trying to reprocess
5337 the trees will break. */
5339 {
5344 }
5347 }
5349 }
5351 /* Substitute ARGS into the vector of template arguments T. */
5353 static tree
5355 tree t;
5356 tree args;
5357 tsubst_flags_t complain;
5358 {
5365 {
5370 else
5373 NULL_TREE));
5380 }
5390 }
5392 /* Return the result of substituting ARGS into the template parameters
5393 given by PARMS. If there are m levels of ARGS and m + n levels of
5394 PARMS, then the result will contain n levels of PARMS. For
5395 example, if PARMS is `template <class T> template <class U>
5396 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
5397 result will be `template <int*, double, class V>'. */
5399 static tree
5401 tree parms;
5402 tree args;
5403 tsubst_flags_t complain;
5404 {
5412 {
5413 tree new_vec =
5418 {
5427 parm_decl);
5429 }
5435 }
5438 }
5440 /* Substitute the ARGS into the indicated aggregate (or enumeration)
5441 type T. If T is not an aggregate or enumeration type, it is
5442 handled as if by tsubst. IN_DECL is as for tsubst. If
5443 ENTERING_SCOPE is non-zero, T is the context for a template which
5444 we are presently tsubst'ing. Return the substituted value. */
5446 static tree
5448 tree t;
5449 tree args;
5450 tsubst_flags_t complain;
5451 tree in_decl;
5453 {
5458 {
5463 /* else fall through */
5467 {
5468 tree argvec;
5469 tree context;
5470 tree r;
5472 /* First, determine the context for the type we are looking
5473 up. */
5476 complain,
5478 else
5481 /* Then, figure out what arguments are appropriate for the
5482 type we are trying to find. For example, given:
5484 template <class T> struct S;
5485 template <class T, class U> void f(T, U) { S<U> su; }
5487 and supposing that we are instantiating f<int, double>,
5488 then our ARGS will be {int, double}, but, when looking up
5489 S we only want {double}. */
5491 complain);
5499 }
5500 else
5501 /* This is not a template type, so there's nothing to do. */
5506 }
5507 }
5509 /* Substitute into the default argument ARG (a default argument for
5510 FN), which has the indicated TYPE. */
5512 tree
5514 tree fn;
5515 tree type;
5516 tree arg;
5517 {
5518 /* This default argument came from a template. Instantiate the
5519 default argument here, not in tsubst. In the case of
5520 something like:
5522 template <class T>
5523 struct S {
5524 static T t();
5525 void f(T = t());
5526 };
5528 we must be careful to do name lookup in the scope of S<T>,
5529 rather than in the current class. */
5539 /* Make sure the default argument is reasonable. */
5543 }
5545 /* Substitute into all the default arguments for FN. */
5547 static void
5549 tree fn;
5550 {
5551 tree arg;
5552 tree tmpl_args;
5556 /* If this function is not yet instantiated, we certainly don't need
5557 its default arguments. */
5562 arg;
5568 }
5570 /* Substitute the ARGS into the T, which is a _DECL. TYPE is the
5571 (already computed) substitution of ARGS into TREE_TYPE (T), if
5572 appropriate. Return the result of the substitution. Issue error
5573 and warning messages under control of COMPLAIN. */
5575 static tree
5577 tree t;
5578 tree args;
5579 tree type;
5580 tsubst_flags_t complain;
5581 {
5589 /* Set the filename and linenumber to improve error-reporting. */
5596 {
5598 {
5599 /* We can get here when processing a member template function
5600 of a template class. */
5602 tree spec;
5606 {
5607 /* We might already have an instance of this template.
5608 The ARGS are for the surrounding class type, so the
5609 full args contain the tsubst'd args for the context,
5610 plus the innermost args from the template decl. */
5614 tree full_args;
5617 complain);
5619 /* tsubst_template_arg_vector doesn't copy the vector if
5620 nothing changed. But, *something* should have
5621 changed. */
5626 {
5629 }
5630 }
5632 /* Make a new template decl. It will be similar to the
5633 original, but will record the current template arguments.
5634 We also create a new function declaration, which is just
5635 like the old one, but points to this new template, rather
5636 than the old one. */
5642 {
5647 }
5660 {
5666 }
5667 else
5668 {
5675 }
5681 /* The template parameters for this new template are all the
5682 template parameters for the old template, except the
5683 outermost level of parameters. */
5686 complain);
5691 /* We don't partially instantiate partial specializations. */
5695 /* Record this partial instantiation. */
5699 }
5703 {
5704 tree ctx;
5707 tree gen_tmpl;
5712 /* Nobody should be tsubst'ing into non-template functions. */
5716 {
5717 tree spec;
5719 /* Calculate the most general template of which R is a
5720 specialization, and the complete set of arguments used to
5721 specialize R. */
5723 argvec
5728 /* Check to see if we already have this specialization. */
5732 {
5735 }
5737 /* We can see more levels of arguments than parameters if
5738 there was a specialization of a member template, like
5739 this:
5741 template <class T> struct S { template <class U> void f(); }
5742 template <> template <class U> void S<int>::f(U);
5744 Here, we'll be substituting into the specialization,
5745 because that's where we can find the code we actually
5746 want to generate, but we'll have enough arguments for
5747 the most general template.
5749 We also deal with the peculiar case:
5751 template <class T> struct S {
5752 template <class U> friend void f();
5753 };
5754 template <class U> void f() {}
5755 template S<int>;
5756 template void f<double>();
5758 Here, the ARGS for the instantiation of will be {int,
5759 double}. But, we only need as many ARGS as there are
5760 levels of template parameters in CODE_PATTERN. We are
5761 careful not to get fooled into reducing the ARGS in
5762 situations like:
5764 template <class T> struct S { template <class U> void f(U); }
5765 template <class T> template <> void S<T>::f(int) {}
5767 which we can spot because the pattern will be a
5768 specialization in this case. */
5770 parms_depth =
5775 }
5776 else
5777 {
5778 /* This special case arises when we have something like this:
5780 template <class T> struct S {
5781 friend void f<int>(int, double);
5782 };
5784 Here, the DECL_TI_TEMPLATE for the friend declaration
5785 will be a LOOKUP_EXPR or an IDENTIFIER_NODE. We are
5786 being called from tsubst_friend_function, and we want
5787 only to create a new decl (R) with appropriate types so
5788 that we can call determine_specialization. */
5794 }
5797 {
5800 else
5805 }
5806 else
5807 {
5810 }
5815 /* We do NOT check for matching decls pushed separately at this
5816 point, as they may not represent instantiations of this
5817 template, and in any case are considered separate under the
5818 discrete model. */
5822 /* Clear out the mangled name and RTL for the instantiation. */
5833 /* Type-conversion operator. Reconstruct the name, in
5834 case it's the name of one of the template's parameters. */
5852 {
5857 }
5859 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
5860 this in the special friend case mentioned above where
5861 GEN_TMPL is NULL. */
5863 {
5869 /* We're not supposed to instantiate default arguments
5870 until they are called, for a template. But, for a
5871 declaration like:
5873 template <class T> void f ()
5874 { extern void g(int i = T()); }
5876 we should do the substitution when the template is
5877 instantiated. We handle the member function case in
5878 instantiate_class_template since the default arguments
5879 might refer to other members of the class. */
5884 }
5886 /* Copy the list of befriending classes. */
5890 {
5894 in_decl);
5895 }
5898 {
5902 /* If this is an instantiation of a member template, clone it.
5903 If it isn't, that'll be handled by
5904 clone_constructors_and_destructors. */
5907 }
5910 }
5914 {
5924 else
5936 }
5940 {
5945 /* We don't have to set DECL_CONTEXT here; it is set by
5946 finish_member_declaration. */
5952 }
5956 {
5961 }
5967 {
5968 /* If this is the canonical decl, we don't have to mess with
5969 instantiations, and often we can't (for typename, template
5970 type parms and such). Note that TYPE_NAME is not correct for
5971 the above test if we've copied the type for a typedef. */
5974 }
5976 /* Fall through. */
5979 {
5982 tree spec;
5984 tree ctx;
5987 /* Assume this is a non-local variable. */
5992 complain,
5996 else
5997 {
5998 /* Subsequent calls to pushdecl will fill this in. */
6001 }
6003 /* Check to see if we already have this specialization. */
6005 {
6010 }
6011 else
6015 {
6018 }
6024 /* Clear out the mangled name and RTL for the instantiation. */
6028 /* Don't try to expand the initializer until someone tries to use
6029 this variable; otherwise we run into circular dependencies. */
6034 /* For __PRETTY_FUNCTION__ we have to adjust the initializer. */
6036 {
6041 }
6043 /* Even if the original location is out of scope, the newly
6044 substituted one is not. */
6049 {
6050 /* A static data member declaration is always marked
6051 external when it is declared in-class, even if an
6052 initializer is present. We mimic the non-template
6053 processing here. */
6059 }
6060 else
6066 }
6071 }
6073 /* Restore the file and line information. */
6078 }
6080 /* Substitue into the ARG_TYPES of a function type. */
6082 static tree
6084 tree arg_types;
6085 tree args;
6086 tsubst_flags_t complain;
6087 tree in_decl;
6088 {
6089 tree remaining_arg_types;
6090 tree type;
6104 {
6106 {
6110 }
6112 }
6114 /* Do array-to-pointer, function-to-pointer conversion, and ignore
6115 top-level qualifiers as required. */
6118 /* Note that we do not substitute into default arguments here. The
6119 standard mandates that they be instantiated only when needed,
6120 which is done in build_over_call. */
6122 remaining_arg_types);
6124 }
6126 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
6127 *not* handle the exception-specification for FNTYPE, because the
6128 initial substitution of explicitly provided template parameters
6129 during argument deduction forbids substitution into the
6130 exception-specification:
6132 [temp.deduct]
6134 All references in the function type of the function template to the
6135 corresponding template parameters are replaced by the specified tem-
6136 plate argument values. If a substitution in a template parameter or
6137 in the function type of the function template results in an invalid
6138 type, type deduction fails. [Note: The equivalent substitution in
6139 exception specifications is done only when the function is instanti-
6140 ated, at which point a program is ill-formed if the substitution
6141 results in an invalid type.] */
6143 static tree
6145 tree t;
6146 tree args;
6147 tsubst_flags_t complain;
6148 tree in_decl;
6149 {
6150 tree return_type;
6151 tree arg_types;
6152 tree fntype;
6154 /* The TYPE_CONTEXT is not used for function/method types. */
6157 /* Substitute the return type. */
6162 /* Substitue the argument types. */
6168 /* Construct a new type node and return it. */
6171 else
6172 {
6175 {
6176 /* [temp.deduct]
6178 Type deduction may fail for any of the following
6179 reasons:
6181 -- Attempting to create "pointer to member of T" when T
6182 is not a class type. */
6185 r);
6187 }
6191 }
6196 }
6198 /* Substitute into the PARMS of a call-declarator. */
6200 static tree
6202 tree parms;
6203 tree args;
6204 tsubst_flags_t complain;
6205 tree in_decl;
6206 {
6207 tree new_parms;
6208 tree type;
6209 tree defarg;
6217 /* Figure out the type of this parameter. */
6220 /* Figure out the default argument as well. Note that we use
6221 tsubst_expr since the default argument is really an expression. */
6224 /* Chain this parameter on to the front of those we have already
6225 processed. We don't use hash_tree_cons because that function
6226 doesn't check TREE_PARMLIST. */
6229 /* And note that these are parameters. */
6233 }
6235 /* Take the tree structure T and replace template parameters used
6236 therein with the argument vector ARGS. IN_DECL is an associated
6237 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
6238 Issue error and warning messages under control of COMPLAIN. Note
6239 that we must be relatively non-tolerant of extensions here, in
6240 order to preserve conformance; if we allow substitutions that
6241 should not be allowed, we may allow argument deductions that should
6242 not succeed, and therefore report ambiguous overload situations
6243 where there are none. In theory, we could allow the substitution,
6244 but indicate that it should have failed, and allow our caller to
6245 make sure that the right thing happens, but we don't try to do this
6246 yet.
6248 This function is used for dealing with types, decls and the like;
6249 for expressions, use tsubst_expr or tsubst_copy. */
6251 tree
6254 tsubst_flags_t complain;
6255 tree in_decl;
6256 {
6268 else
6287 {
6314 {
6321 /* See if we can reduce this expression to something simpler. */
6327 /* When providing explicit arguments to a template
6328 function, but leaving some arguments for subsequent
6329 deduction, MAX may be template-dependent even if we're
6330 not PROCESSING_TEMPLATE_DECL. We still need to check for
6331 template parms, though; MAX won't be an INTEGER_CST for
6332 dynamic arrays, either. */
6335 {
6339 integer_one_node);
6341 }
6344 {
6345 /* Still allow an explicit array of size zero. */
6348 }
6352 {
6353 /* [temp.deduct]
6355 Type deduction may fail for any of the following
6356 reasons:
6358 Attempting to create an array with a size that is
6359 zero or negative. */
6364 }
6367 }
6373 {
6383 {
6386 }
6387 else
6388 {
6391 }
6394 {
6404 {
6406 {
6408 return cp_build_qualified_type_real
6410 complain);
6411 }
6413 {
6414 /* We are processing a type constructed from
6415 a template template parameter */
6421 /* We can get a TEMPLATE_TEMPLATE_PARM here when
6422 we are resolving nested-types in the signature of
6423 a member function templates.
6424 Otherwise ARG is a TEMPLATE_DECL and is the real
6425 template to be instantiated. */
6433 complain);
6434 return cp_build_qualified_type_real
6436 }
6437 else
6438 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
6440 }
6441 }
6442 else
6446 /* This can happen during the attempted tsubst'ing in
6447 unify. This means that we don't yet have any information
6448 about the template parameter in question. */
6451 /* If we get here, we must have been looking at a parm for a
6452 more deeply nested template. Make a new version of this
6453 template parameter, but with a lower level. */
6455 {
6460 {
6462 r = cp_build_qualified_type_real
6464 }
6465 else
6466 {
6477 {
6485 }
6486 }
6495 }
6498 }
6501 {
6509 {
6513 }
6516 {
6520 }
6523 {
6527 }
6533 {
6536 }
6537 else
6540 }
6543 {
6544 /* A binfo node. We always need to make a copy, of the node
6545 itself and of its BINFO_BASETYPES. */
6549 /* Make sure type isn't a typedef copy. */
6554 {
6559 }
6561 }
6563 /* Otherwise, a vector of template arguments. */
6568 {
6577 /* [temp.deduct]
6579 Type deduction may fail for any of the following
6580 reasons:
6582 -- Attempting to create a pointer to reference type.
6583 -- Attempting to create a reference to a reference type or
6584 a reference to void. */
6587 {
6591 /* We keep track of the last time we issued this error
6592 message to avoid spewing a ton of messages during a
6593 single bad template instantiation. */
6596 {
6599 else
6602 type);
6605 }
6608 }
6610 {
6614 }
6615 else
6620 /* Will this ever be needed for TYPE_..._TO values? */
6624 }
6626 {
6629 {
6630 /* [temp.deduct]
6632 Type deduction may fail for any of the following
6633 reasons:
6635 -- Attempting to create "pointer to member of T" when T
6636 is not a class type. */
6640 }
6642 {
6647 }
6650 /* This is really a method type. The cv qualifiers of the
6651 this pointer should _not_ be determined by the cv
6652 qualifiers of the class type. They should be held
6653 somewhere in the FUNCTION_TYPE, but we don't do that at
6654 the moment. Consider
6655 typedef void (Func) () const;
6657 template <typename T1> void Foo (Func T1::*);
6659 */
6663 else
6665 }
6668 {
6669 tree fntype;
6670 tree raises;
6676 /* Substitue the exception specification. */
6679 {
6684 else
6686 {
6693 }
6695 }
6697 }
6699 {
6704 /* As an optimization, we avoid regenerating the array type if
6705 it will obviously be the same as T. */
6709 /* These checks should match the ones in grokdeclarator.
6711 [temp.deduct]
6713 The deduction may fail for any of the following reasons:
6715 -- Attempting to create an array with an element type that
6716 is void, a function type, or a reference type. */
6720 {
6724 }
6728 }
6732 {
6740 }
6744 {
6750 }
6753 {
6763 {
6766 ctx);
6768 }
6770 {
6771 /* Normally, make_typename_type does not require that the CTX
6772 have complete type in order to allow things like:
6774 template <class T> struct S { typename S<T>::X Y; };
6776 But, such constructs have already been resolved by this
6777 point, so here CTX really should have complete type, unless
6778 it's a partial instantiation. */
6781 {
6785 }
6786 }
6791 return cp_build_qualified_type_real
6793 }
6796 {
6805 }
6808 {
6813 }
6816 {
6821 }
6824 {
6831 }
6834 {
6836 tree e2 = (tsubst_call_declarator_parms
6846 }
6849 {
6856 }
6859 {
6865 }
6871 }
6872 }
6874 /* Like tsubst, but deals with expressions. This function just replaces
6875 template parms; to finish processing the resultant expression, use
6876 tsubst_expr. */
6878 tree
6881 tsubst_flags_t complain;
6882 tree in_decl;
6883 {
6885 tree r;
6893 {
6898 {
6899 tree enum_type;
6900 tree v;
6903 /* This is a global enumeration constant. */
6906 /* Unfortunately, we cannot just call lookup_name here.
6907 Consider:
6909 template <int I> int f() {
6910 enum E { a = I };
6911 struct S { void g() { E e = a; } };
6912 };
6914 When we instantiate f<7>::S::g(), say, lookup_name is not
6915 clever enough to find f<7>::a. */
6916 enum_type
6926 /* We didn't find the name. That should never happen; if
6927 name-lookup found it during preliminary parsing, we
6928 should find it again here during instantiation. */
6930 }
6935 {
6936 tree ctx;
6942 }
6955 else
6959 {
6960 /* We must tsubst into a LOOKUP_EXPR in case the names to
6961 which it refers is a conversion operator; in that case the
6962 name will change. We avoid making unnecessary copies,
6963 however. */
6968 {
6972 }
6975 }
6983 return build1
7000 return build1
7044 return build_nt
7049 {
7053 else
7054 /* Sometimes FN is a LOOKUP_EXPR. */
7056 return build_nt
7058 in_decl),
7059 NULL_TREE);
7060 }
7063 {
7066 {
7070 }
7073 {
7081 }
7082 else
7084 return build_nt
7088 NULL_TREE);
7089 }
7092 /* This processing should really occur in tsubst_expr, However,
7093 tsubst_expr does not recurse into expressions, since it
7094 assumes that there aren't any statements inside them.
7095 Instead, it simply calls build_expr_from_tree. So, we need
7096 to expand the STMT_EXPR here. */
7098 {
7102 }
7109 {
7110 r = build_nt
7115 }
7118 {
7119 r = build_nt
7125 }
7128 {
7129 r = build_nt
7135 }
7138 {
7139 /* Substituted template arguments */
7141 in_decl);
7144 {
7145 tree chain;
7148 }
7150 {
7155 }
7157 return lookup_template_function
7159 }
7162 {
7182 }
7206 {
7209 }
7210 else
7214 {
7215 r = build
7221 }
7225 in_decl),
7230 }
7231 }
7233 /* Like tsubst_copy, but also does semantic processing. */
7235 tree
7238 tsubst_flags_t complain;
7239 tree in_decl;
7240 {
7253 {
7256 finish_named_return_value
7262 {
7263 tree member_init_list;
7264 tree base_init_list;
7267 member_init_list
7269 base_init_list
7273 }
7294 {
7295 tree decl;
7296 tree init;
7303 {
7309 }
7310 else
7311 {
7316 else
7319 {
7321 /* Make sure the type is instantiated now. */
7325 /* By marking the declaration as instantiated, we avoid
7326 trying to instantiate it. Since instantiate_decl can't
7327 handle local variables, and since we've already done
7328 all that needs to be done, that's the right thing to
7329 do. */
7334 }
7335 }
7337 /* A DECL_STMT can also be used as an expression, in the condition
7338 clause of a if/for/while construct. If we aren't followed by
7339 another statement, return our decl. */
7342 }
7346 {
7354 stmt);
7359 }
7363 {
7368 stmt);
7371 }
7375 {
7382 stmt);
7383 }
7387 {
7392 stmt);
7395 {
7398 }
7401 {
7405 }
7408 }
7412 {
7416 else
7423 else
7425 }
7439 {
7440 tree val;
7448 }
7455 in_decl));
7467 /* Computed goto's must be tsubst'd into. On the other hand,
7468 non-computed gotos must not be; the identifier in question
7469 will have no binding. */
7471 else
7483 in_decl));
7489 {
7495 stmt);
7496 }
7497 else
7498 {
7501 else
7508 else
7514 else
7516 }
7520 {
7521 tree decl;
7526 {
7529 /* Prevent instantiate_decl from trying to instantiate
7530 this variable. We've already done all that needs to be
7531 done. */
7533 }
7534 else
7539 }
7553 }
7556 }
7558 /* Instantiate the indicated variable or function template TMPL with
7559 the template arguments in TARG_PTR. */
7561 tree
7564 {
7565 tree fndecl;
7566 tree gen_tmpl;
7567 tree spec;
7569 tree inner_args;
7576 /* If this function is a clone, handle it specially. */
7578 {
7580 tree clone;
7582 /* Look for the clone. */
7588 /* We should always have found the clone by now. */
7591 }
7593 /* Check to see if we already have this specialization. */
7600 {
7601 /* The TMPL is a partial instantiation. To get a full set of
7602 arguments we must add the arguments used to perform the
7603 partial instantiation. */
7605 targ_ptr);
7607 /* Check to see if we already have this specialization. */
7611 }
7617 {
7620 {
7623 {
7627 }
7628 }
7629 }
7631 /* substitute template parameters */
7634 /* The DECL_TI_TEMPLATE should always be the immediate parent
7635 template, not the most general template. */
7641 /* If we've just instantiated the main entry point for a function,
7642 instantiate all the alternate entry points as well. We do this
7643 by cloning the instantiation of the main entry point, not by
7644 instantiating the template clones. */
7649 }
7651 /* The FN is a TEMPLATE_DECL for a function. The ARGS are the
7652 arguments that are being used when calling it. TARGS is a vector
7653 into which the deduced template arguments are placed.
7655 Return zero for success, 2 for an incomplete match that doesn't resolve
7656 all the types, and 1 for complete failure. An error message will be
7657 printed only for an incomplete match.
7659 If FN is a conversion operator, or we are trying to produce a specific
7660 specialization, RETURN_TYPE is the return type desired.
7662 The EXPLICIT_TARGS are explicit template arguments provided via a
7663 template-id.
7665 The parameter STRICT is one of:
7667 DEDUCE_CALL:
7668 We are deducing arguments for a function call, as in
7669 [temp.deduct.call].
7671 DEDUCE_CONV:
7672 We are deducing arguments for a conversion function, as in
7673 [temp.deduct.conv].
7675 DEDUCE_EXACT:
7676 We are deducing arguments when doing an explicit instantiation
7677 as in [temp.explicit], when determining an explicit specialization
7678 as in [temp.expl.spec], or when taking the address of a function
7679 template, as in [temp.deduct.funcaddr].
7681 DEDUCE_ORDER:
7682 We are deducing arguments when calculating the partial
7683 ordering between specializations of function or class
7684 templates, as in [temp.func.order] and [temp.class.order].
7686 LEN is the number of parms to consider before returning success, or -1
7687 for all. This is used in partial ordering to avoid comparing parms for
7688 which no actual argument was passed, since they are not considered in
7689 overload resolution (and are explicitly excluded from consideration in
7690 partial ordering in [temp.func.order]/6). */
7692 int
7696 unification_kind_t strict;
7698 {
7699 tree parms;
7700 tree fntype;
7707 {
7708 /* [temp.deduct]
7710 The specified template arguments must match the template
7711 parameters in kind (i.e., type, nontype, template), and there
7712 must not be more arguments than there are parameters;
7713 otherwise type deduction fails.
7715 Nontype arguments must match the types of the corresponding
7716 nontype template parameters, or must be convertible to the
7717 types of the corresponding nontype parameters as specified in
7718 _temp.arg.nontype_, otherwise type deduction fails.
7720 All references in the function type of the function template
7721 to the corresponding template parameters are replaced by the
7722 specified template argument values. If a substitution in a
7723 template parameter or in the function type of the function
7724 template results in an invalid type, type deduction fails. */
7726 tree converted_args;
7728 converted_args
7739 /* Place the explicitly specified arguments in TARGS. */
7742 }
7745 /* Never do unification on the 'this' parameter. */
7750 {
7751 /* We've been given a return type to match, prepend it. */
7756 }
7758 /* We allow incomplete unification without an error message here
7759 because the standard doesn't seem to explicitly prohibit it. Our
7760 callers must be ready to deal with unification failures in any
7761 event. */
7767 /* All is well so far. Now, check:
7769 [temp.deduct]
7771 When all template arguments have been deduced, all uses of
7772 template parameters in nondeduced contexts are replaced with
7773 the corresponding deduced argument values. If the
7774 substitution results in an invalid type, as described above,
7775 type deduction fails. */
7781 }
7783 /* Adjust types before performing type deduction, as described in
7784 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
7785 sections are symmetric. PARM is the type of a function parameter
7786 or the return type of the conversion function. ARG is the type of
7787 the argument passed to the call, or the type of the value
7788 initialized with the result of the conversion function. */
7790 static int
7792 unification_kind_t strict;
7795 {
7799 {
7804 {
7805 /* Swap PARM and ARG throughout the remainder of this
7806 function; the handling is precisely symmetric since PARM
7807 will initialize ARG rather than vice versa. */
7812 }
7815 /* There is nothing to do in this case. */
7819 /* DR 214. [temp.func.order] is underspecified, and leads to no
7820 ordering between things like `T *' and `T const &' for `U *'.
7821 The former has T=U and the latter T=U*. The former looks more
7822 specialized and John Spicer considers it well-formed (the EDG
7823 compiler accepts it).
7825 John also confirms that deduction should proceed as in a function
7826 call. Which implies the usual ARG and PARM conversions as DEDUCE_CALL.
7827 However, in ordering, ARG can have REFERENCE_TYPE, but no argument
7828 to an actual call can have such a type.
7830 If both ARG and PARM are REFERENCE_TYPE, we change neither.
7831 If only ARG is a REFERENCE_TYPE, we look through that and then
7832 proceed as with DEDUCE_CALL (which could further convert it). */
7834 {
7838 }
7842 }
7845 {
7846 /* [temp.deduct.call]
7848 If P is not a reference type:
7850 --If A is an array type, the pointer type produced by the
7851 array-to-pointer standard conversion (_conv.array_) is
7852 used in place of A for type deduction; otherwise,
7854 --If A is a function type, the pointer type produced by
7855 the function-to-pointer standard conversion
7856 (_conv.func_) is used in place of A for type deduction;
7857 otherwise,
7859 --If A is a cv-qualified type, the top level
7860 cv-qualifiers of A's type are ignored for type
7861 deduction. */
7866 else
7868 }
7870 /* [temp.deduct.call]
7872 If P is a cv-qualified type, the top level cv-qualifiers
7873 of P's type are ignored for type deduction. If P is a
7874 reference type, the type referred to by P is used for
7875 type deduction. */
7878 {
7881 }
7883 }
7885 /* Most parms like fn_type_unification.
7887 If SUBR is 1, we're being called recursively (to unify the
7888 arguments of a function or method parameter of a function
7889 template). */
7891 static int
7896 unification_kind_t strict;
7898 {
7910 /* ARGS could be NULL (via a call from parse.y to
7911 build_x_function_call). */
7917 {
7937 }
7942 again:
7949 && args
7951 {
7960 /* We can't deduce anything from this, but we might get all the
7961 template args from other function args. */
7964 /* Conversions will be performed on a function argument that
7965 corresponds with a function parameter that contains only
7966 non-deducible template parameters and explicitly specified
7967 template parameters. */
7969 {
7970 tree type;
7974 else
7975 {
7978 }
7981 {
7984 }
7985 else
7986 /* It might work; we shouldn't check now, because we might
7987 get into infinite recursion. Overload resolution will
7988 handle it. */
7992 }
7995 {
7998 {
7999 /* [temp.deduct.type] A template-argument can be deduced from
8000 a pointer to function or pointer to member function
8001 argument if the set of overloaded functions does not
8002 contain function templates and at most one of a set of
8003 overloaded functions provides a unique match. */
8010 }
8012 }
8014 {
8022 }
8024 /* Are we done with the interesting parms? */
8027 }
8028 /* Fail if we've reached the end of the parm list, and more args
8029 are present, and the parm list isn't variadic. */
8032 /* Fail if parms are left and they don't have default values. */
8038 done:
8042 {
8045 /* If this is an undeduced nontype parameter that depends on
8046 a type parameter, try another pass; its type may have been
8047 deduced from a later argument than the one from which
8048 this parameter can be deduced. */
8057 }
8059 }
8061 /* Subroutine of type_unification_real. Args are like the variables at the
8062 call site. ARG is an overloaded function (or template-id); we try
8063 deducing template args from each of the overloads, and if only one
8064 succeeds, we go with that. Modifies TARGS and returns 0 on success. */
8066 static int
8068 sub_strict)
8070 unification_kind_t strict;
8072 {
8080 /* Handle `&x' where `x' is some static or non-static member
8081 function name. */
8087 /* Strip baselink information. */
8092 {
8093 /* If we got some explicit template args, we need to plug them into
8094 the affected templates before we try to unify, in case the
8095 explicit args will completely resolve the templates in question. */
8101 {
8109 expl_subargs);
8111 {
8117 }
8118 }
8119 }
8121 {
8123 {
8128 type,
8130 }
8131 }
8132 else
8135 /* [temp.deduct.type] A template-argument can be deduced from a pointer
8136 to function or pointer to member function argument if the set of
8137 overloaded functions does not contain function templates and at most
8138 one of a set of overloaded functions provides a unique match.
8140 So if we found multiple possibilities, we return success but don't
8141 deduce anything. */
8144 {
8149 }
8154 }
8156 /* Subroutine of resolve_overloaded_unification; does deduction for a single
8157 overload. Fills TARGS with any deduced arguments, or error_mark_node if
8158 different overloads deduce different arguments for a given parm.
8159 Returns 1 on success. */
8161 static int
8163 sub_strict)
8165 unification_kind_t strict;
8167 {
8169 tree tempargs;
8172 /* [temp.deduct.type] A template-argument can be deduced from a pointer
8173 to function or pointer to member function argument if the set of
8174 overloaded functions does not contain function templates and at most
8175 one of a set of overloaded functions provides a unique match.
8177 So if this is a template, just return success. */
8184 /* We don't copy orig_targs for this because if we have already deduced
8185 some template args from previous args, unify would complain when we
8186 try to deduce a template parameter for the same argument, even though
8187 there isn't really a conflict. */
8194 /* First make sure we didn't deduce anything that conflicts with
8195 explicitly specified args. */
8197 {
8204 {
8205 /* Since we're unifying against ourselves, we will fill in template
8206 args used in the function parm list with our own template parms.
8207 Discard them. */
8210 }
8213 }
8216 {
8221 }
8224 }
8226 /* Verify that nondeduce template argument agrees with the type
8227 obtained from argument deduction. Return nonzero if the
8228 verification fails.
8230 For example:
8232 struct A { typedef int X; };
8233 template <class T, class U> struct C {};
8234 template <class T> struct C<T, typename T::X> {};
8236 Then with the instantiation `C<A, int>', we can deduce that
8237 `T' is `A' but unify () does not check whether `typename T::X'
8238 is `int'. This function ensure that they agree.
8240 TARGS, PARMS are the same as the arguments of unify.
8241 ARGS contains template arguments from all levels. */
8243 static int
8246 {
8257 {
8261 /* In case we are deducing from a function argument of a function
8262 templates, some parameters may not be deduced yet. So we
8263 make sure that only fully substituted elements of PARM are
8264 compared below. */
8268 }
8270 }
8272 /* PARM is a template class (perhaps with unbound template
8273 parameters). ARG is a fully instantiated type. If ARG can be
8274 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
8275 TARGS are as for unify. */
8277 static tree
8279 tree tparms;
8280 tree targs;
8281 tree parm;
8282 tree arg;
8283 {
8284 tree copy_of_targs;
8290 /* We need to make a new template argument vector for the call to
8291 unify. If we used TARGS, we'd clutter it up with the result of
8292 the attempted unification, even if this class didn't work out.
8293 We also don't want to commit ourselves to all the unifications
8294 we've already done, since unification is supposed to be done on
8295 an argument-by-argument basis. In other words, consider the
8296 following pathological case:
8298 template <int I, int J, int K>
8299 struct S {};
8301 template <int I, int J>
8302 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
8304 template <int I, int J, int K>
8305 void f(S<I, J, K>, S<I, I, I>);
8307 void g() {
8308 S<0, 0, 0> s0;
8309 S<0, 1, 2> s2;
8311 f(s0, s2);
8312 }
8314 Now, by the time we consider the unification involving `s2', we
8315 already know that we must have `f<0, 0, 0>'. But, even though
8316 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is not legal
8317 because there are two ways to unify base classes of S<0, 1, 2>
8318 with S<I, I, I>. If we kept the already deduced knowledge, we
8319 would reject the possibility I=1. */
8322 /* If unification failed, we're done. */
8328 }
8330 /* Subroutine of get_template_base. RVAL, if non-NULL, is a base we
8331 have already discovered to be satisfactory. ARG_BINFO is the binfo
8332 for the base class of ARG that we are currently examining. */
8334 static tree
8337 tree tparms;
8338 tree targs;
8339 tree arg_binfo;
8340 tree rval;
8341 tree parm;
8343 {
8344 tree binfos;
8349 {
8353 /* If there is more than one satisfactory baseclass, then:
8355 [temp.deduct.call]
8357 If they yield more than one possible deduced A, the type
8358 deduction fails.
8360 applies. */
8365 }
8370 /* Process base types. */
8372 {
8376 /* Skip this base, if we've already seen it. */
8380 this_virtual =
8383 /* When searching for a non-virtual, we cannot mark virtually
8384 found binfos. */
8389 parm,
8390 base_binfo,
8391 rval,
8394 /* If we discovered more than one matching base class, we can
8395 stop now. */
8398 }
8401 }
8403 /* Given a template type PARM and a class type ARG, find the unique
8404 base type in ARG that is an instance of PARM. We do not examine
8405 ARG itself; only its base-classes. If there is no appropriate base
8406 class, return NULL_TREE. If there is more than one, return
8407 error_mark_node. PARM may be the type of a partial specialization,
8408 as well as a plain template type. Used by unify. */
8410 static tree
8412 tree tparms;
8413 tree targs;
8414 tree parm;
8415 tree arg;
8416 {
8417 tree rval;
8418 tree arg_binfo;
8425 NULL_TREE,
8426 GTB_IGNORE_TYPE);
8428 /* Since get_template_base_recursive marks the bases classes, we
8429 must unmark them here. */
8433 }
8435 /* Returns the level of DECL, which declares a template parameter. */
8437 static int
8439 tree decl;
8440 {
8442 {
8453 }
8454 }
8456 /* Decide whether ARG can be unified with PARM, considering only the
8457 cv-qualifiers of each type, given STRICT as documented for unify.
8458 Returns non-zero iff the unification is OK on that basis.*/
8460 static int
8463 tree arg;
8464 tree parm;
8465 {
8475 }
8477 /* Takes parameters as for type_unification. Returns 0 if the
8478 type deduction succeeds, 1 otherwise. The parameter STRICT is a
8479 bitwise or of the following flags:
8481 UNIFY_ALLOW_NONE:
8482 Require an exact match between PARM and ARG.
8483 UNIFY_ALLOW_MORE_CV_QUAL:
8484 Allow the deduced ARG to be more cv-qualified (by qualification
8485 conversion) than ARG.
8486 UNIFY_ALLOW_LESS_CV_QUAL:
8487 Allow the deduced ARG to be less cv-qualified than ARG.
8488 UNIFY_ALLOW_DERIVED:
8489 Allow the deduced ARG to be a template base class of ARG,
8490 or a pointer to a template base class of the type pointed to by
8491 ARG.
8492 UNIFY_ALLOW_INTEGER:
8493 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
8494 case for more information.
8495 UNIFY_ALLOW_OUTER_LEVEL:
8496 This is the outermost level of a deduction. Used to determine validity
8497 of qualification conversions. A valid qualification conversion must
8498 have const qualified pointers leading up to the inner type which
8499 requires additional CV quals, except at the outer level, where const
8500 is not required [conv.qual]. It would be normal to set this flag in
8501 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
8502 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
8503 This is the outermost level of a deduction, and PARM can be more CV
8504 qualified at this point.
8505 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
8506 This is the outermost level of a deduction, and PARM can be less CV
8507 qualified at this point.
8508 UNIFY_ALLOW_MAX_CORRECTION:
8509 This is an INTEGER_TYPE's maximum value. Used if the range may
8510 have been derived from a size specification, such as an array size.
8511 If the size was given by a nontype template parameter N, the maximum
8512 value will have the form N-1. The flag says that we can (and indeed
8513 must) unify N with (ARG + 1), an exception to the normal rules on
8514 folding PARM. */
8516 static int
8520 {
8522 tree targ;
8523 tree tparm;
8526 /* I don't think this will do the right thing with respect to types.
8527 But the only case I've seen it in so far has been array bounds, where
8528 signedness is the only information lost, and I think that will be
8529 okay. */
8536 /* We can't deduce anything from this, but we might get all the
8537 template args from other function args. */
8540 /* If PARM uses template parameters, then we can't bail out here,
8541 even if ARG == PARM, since we won't record unifications for the
8542 template parameters. We might need them if we're trying to
8543 figure out which of two things is more specialized. */
8547 /* Immediately reject some pairs that won't unify because of
8548 cv-qualification mismatches. */
8551 /* It is the elements of the array which hold the cv quals of an array
8552 type, and the elements might be template type parms. We'll check
8553 when we recurse. */
8555 /* We check the cv-qualifiers when unifying with template type
8556 parameters below. We want to allow ARG `const T' to unify with
8557 PARM `T' for example, when computing which of two templates
8558 is more specialized, for example. */
8573 {
8577 /* In a type which contains a nested-name-specifier, template
8578 argument values cannot be deduced for template parameters used
8579 within the nested-name-specifier. */
8589 /* The PARM is not one we're trying to unify. Just check
8590 to see if it matches ARG. */
8597 /* Check for mixed types and values. */
8605 {
8606 /* ARG must be constructed from a template class or a template
8607 template parameter. */
8612 {
8616 tree argtmplvec
8620 /* The parameter and argument roles have to be switched here
8621 in order to handle default arguments properly. For example,
8622 template<template <class> class TT> void f(TT<int>)
8623 should be able to accept vector<int> which comes from
8624 template <class T, class Allocator = allocator>
8625 class vector. */
8631 /* Deduce arguments T, i from TT<T> or TT<i>.
8632 We check each element of PARMVEC and ARGVEC individually
8633 rather than the whole TREE_VEC since they can have
8634 different number of elements. */
8637 {
8642 UNIFY_ALLOW_NONE))
8644 }
8645 }
8648 /* Fall through to deduce template name. */
8649 }
8653 {
8654 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
8656 /* Simple cases: Value already set, does match or doesn't. */
8661 }
8662 else
8663 {
8664 /* If PARM is `const T' and ARG is only `int', we don't have
8665 a match unless we are allowing additional qualification.
8666 If ARG is `const int' and PARM is just `T' that's OK;
8667 that binds `const int' to `T'. */
8672 /* Consider the case where ARG is `const volatile int' and
8673 PARM is `const T'. Then, T should be `volatile int'. */
8674 arg = cp_build_qualified_type_real
8679 /* Simple cases: Value already set, does match or doesn't. */
8684 }
8686 /* Make sure that ARG is not a variable-sized array. (Note that
8687 were talking about variable-sized arrays (like `int[n]'),
8688 rather than arrays of unknown size (like `int[]').) We'll
8689 get very confused by such a type since the bound of the array
8690 will not be computable in an instantiation. Besides, such
8691 types are not allowed in ISO C++, so we can do as we please
8692 here. */
8708 /* The PARM is not one we're trying to unify. Just check
8709 to see if it matches ARG. */
8717 {
8723 else
8725 }
8727 /* [temp.deduct.type] If, in the declaration of a function template
8728 with a non-type template-parameter, the non-type
8729 template-parameter is used in an expression in the function
8730 parameter-list and, if the corresponding template-argument is
8731 deduced, the template-argument type shall match the type of the
8732 template-parameter exactly, except that a template-argument
8733 deduced from an array bound may be of any integral type.
8734 The non-type parameter might use already deduced type parameters. */
8743 /* We haven't deduced the type of this parameter yet. Try again
8744 later. */
8746 else
8753 {
8757 /* [temp.deduct.call]
8759 A can be another pointer or pointer to member type that can
8760 be converted to the deduced A via a qualification
8761 conversion (_conv.qual_).
8763 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
8764 This will allow for additional cv-qualification of the
8765 pointed-to types if appropriate. */
8768 /* The derived-to-base conversion only persists through one
8769 level of pointers. */
8774 {
8775 /* Avoid getting confused about cv-quals; don't recurse here.
8776 Pointers to members should really be just OFFSET_TYPE, not
8777 this two-level nonsense... */
8782 }
8786 }
8805 UNIFY_ALLOW_NONE);
8818 {
8828 }
8829 /* We have already checked cv-qualification at the top of the
8830 function. */
8834 /* As far as unification is concerned, this wins. Later checks
8835 will invalidate it if necessary. */
8838 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
8839 /* Type INTEGER_CST can come from ordinary constant template args. */
8849 {
8858 UNIFY_ALLOW_NONE))
8861 }
8869 {
8876 strict);
8877 }
8880 {
8884 {
8885 /* First, we try to unify the PARM and ARG directly. */
8890 {
8891 /* Fallback to the special case allowed in
8892 [temp.deduct.call]:
8894 If P is a class, and P has the form
8895 template-id, then A can be a derived class of
8896 the deduced A. Likewise, if P is a pointer to
8897 a class of the form template-id, A can be a
8898 pointer to a derived class pointed to by the
8899 deduced A. */
8905 }
8906 }
8910 /* Perhaps PARM is something like S<U> and ARG is S<int>.
8911 Then, we should unify `int' and `U'. */
8913 else
8914 /* There's no chance of unification succeeding. */
8919 }
8937 offset:
8944 strict);
8952 /* Matched cases are handled by the ARG == PARM test above. */
8958 {
8959 /* We handle this case specially, since it comes up with
8960 arrays. In particular, something like:
8962 template <int N> void f(int (&x)[N]);
8964 Here, we are trying to unify the range type, which
8965 looks like [0 ... (N - 1)]. */
8973 }
8974 /* else fall through */
8978 {
8980 /* We're looking at an expression. This can happen with
8981 something like:
8983 template <int I>
8984 void foo(S<I>, S<I + 2>);
8986 This is a "nondeduced context":
8988 [deduct.type]
8990 The nondeduced contexts are:
8992 --A type that is a template-id in which one or more of
8993 the template-arguments is an expression that references
8994 a template-parameter.
8996 In these cases, we assume deduction succeeded, but don't
8997 actually infer any unifications. */
9002 else
9004 }
9005 else
9010 }
9011 }
9012 \f
9013 /* Called if RESULT is explicitly instantiated, or is a member of an
9014 explicitly instantiated class, or if using -frepo and the
9015 instantiation of RESULT has been assigned to this file. */
9017 void
9019 tree result;
9021 {
9023 /* The TREE_PUBLIC flag for function declarations will have been
9024 set correctly by tsubst. */
9027 /* We used to set this unconditionally; we moved that to
9028 do_decl_instantiation so it wouldn't get set on members of
9029 explicit class template instantiations. But we still need to set
9030 it here for the 'extern template' case in order to suppress
9031 implicit instantiations. */
9036 {
9040 /* Always make artificials weak. */
9043 /* For WIN32 we also want to put explicit instantiations in
9044 linkonce sections. */
9047 }
9050 }
9052 /* Given two function templates PAT1 and PAT2, return:
9054 DEDUCE should be DEDUCE_EXACT or DEDUCE_ORDER.
9056 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
9057 -1 if PAT2 is more specialized than PAT1.
9058 0 if neither is more specialized.
9060 LEN is passed through to fn_type_unification. */
9062 int
9067 {
9068 tree targs;
9082 }
9084 /* Given two class template specialization list nodes PAT1 and PAT2, return:
9086 1 if PAT1 is more specialized than PAT2 as described in [temp.class.order].
9087 -1 if PAT2 is more specialized than PAT1.
9088 0 if neither is more specialized. */
9090 int
9093 {
9094 tree targs;
9108 }
9110 /* Return the template arguments that will produce the function signature
9111 DECL from the function template FN, with the explicit template
9112 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is 1, the return type must
9113 also match. Return NULL_TREE if no satisfactory arguments could be
9114 found. DEDUCE and LEN are passed through to fn_type_unification. */
9116 static tree
9120 {
9123 tree decl_type;
9124 tree decl_arg_types;
9127 /* Substitute the explicit template arguments into the type of DECL.
9128 The call to fn_type_unification will handle substitution into the
9129 FN. */
9132 {
9133 tree tmpl;
9134 tree converted_args;
9138 else
9139 /* We can get here for some illegal specializations. */
9142 converted_args
9152 }
9155 /* Never do unification on the 'this' parameter. */
9160 decl_arg_types,
9169 }
9171 /* For most uses, we want to check the return type. */
9173 tree
9176 {
9178 }
9180 /* But for resolve_overloaded_unification, we only care about the parameter
9181 types. */
9183 static tree
9186 {
9188 }
9190 /* Return the innermost template arguments that, when applied to a
9191 template specialization whose innermost template parameters are
9192 TPARMS, and whose specialization arguments are PARMS, yield the
9193 ARGS.
9195 For example, suppose we have:
9197 template <class T, class U> struct S {};
9198 template <class T> struct S<T*, int> {};
9200 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
9201 {T}, the PARMS will be {T*, int} and the ARGS will be {double*,
9202 int}. The resulting vector will be {double}, indicating that `T'
9203 is bound to `double'. */
9205 static tree
9208 {
9213 UNIFY_ALLOW_NONE))
9224 }
9226 /* In INSTANTIATIONS is a list of <INSTANTIATION, TEMPLATE> pairs.
9227 Pick the most specialized template, and return the corresponding
9228 instantiation, or if there is no corresponding instantiation, the
9229 template itself. If there is no most specialized template,
9230 error_mark_node is returned. If there are no templates at all,
9231 NULL_TREE is returned. */
9233 tree
9235 tree instantiations;
9236 {
9245 {
9249 ;
9250 else
9251 {
9253 {
9257 }
9259 }
9260 }
9263 {
9268 }
9271 }
9273 /* Return the most specialized of the list of templates in FNS that can
9274 produce an instantiation matching DECL, given the explicit template
9275 arguments EXPLICIT_ARGS. */
9277 static tree
9280 {
9285 {
9291 }
9294 }
9296 /* If DECL is a specialization of some template, return the most
9297 general such template. Otherwise, returns NULL_TREE.
9299 For example, given:
9301 template <class T> struct S { template <class U> void f(U); };
9303 if TMPL is `template <class U> void S<int>::f(U)' this will return
9304 the full template. This function will not trace past partial
9305 specializations, however. For example, given in addition:
9307 template <class T> struct S<T*> { template <class U> void f(U); };
9309 if TMPL is `template <class U> void S<int*>::f(U)' this will return
9310 `template <class T> template <class U> S<T*>::f(U)'. */
9312 tree
9314 tree decl;
9315 {
9316 /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is
9317 an immediate specialization. */
9319 {
9323 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a
9324 template friend. */
9329 }
9331 /* Look for more and more general templates. */
9333 {
9334 /* The DECL_TI_TEMPLATE can be a LOOKUP_EXPR or IDENTIFIER_NODE
9335 in some cases. (See cp-tree.h for details.) */
9339 /* Stop if we run into an explicitly specialized class template. */
9346 }
9349 }
9351 /* Return the most specialized of the class template specializations
9352 of TMPL which can produce an instantiation matching ARGS, or
9353 error_mark_node if the choice is ambiguous. */
9355 static tree
9357 tree tmpl;
9358 tree args;
9359 {
9361 tree t;
9362 tree champ;
9367 {
9368 tree spec_args
9371 {
9374 }
9375 }
9384 {
9387 ;
9388 else
9389 {
9391 {
9395 }
9397 }
9398 }
9401 {
9405 }
9408 }
9410 /* called from the parser. */
9412 void
9415 {
9421 /* An error occurred, for which grokdeclarator has already issued
9422 an appropriate message. */
9425 {
9428 }
9430 {
9431 /* There is an asymmetry here in the way VAR_DECLs and
9432 FUNCTION_DECLs are handled by grokdeclarator. In the case of
9433 the latter, the DECL we get back will be marked as a
9434 template instantiation, and the appropriate
9435 DECL_TEMPLATE_INFO will be set up. This does not happen for
9436 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
9437 should handle VAR_DECLs as it currently handles
9438 FUNCTION_DECLs. */
9441 {
9444 }
9445 }
9447 {
9450 }
9451 else
9454 /* Check for various error cases. Note that if the explicit
9455 instantiation is legal the RESULT will currently be marked as an
9456 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
9457 until we get here. */
9460 {
9461 /* [temp.spec]
9463 No program shall both explicitly instantiate and explicitly
9464 specialize a template. */
9468 }
9470 {
9471 /* [temp.spec]
9473 No program shall explicitly instantiate any template more
9474 than once.
9476 We check DECL_INTERFACE_KNOWN so as not to complain when the first
9477 instantiation was `extern' and the second is not, and EXTERN_P for
9478 the opposite case. If -frepo, chances are we already got marked
9479 as an explicit instantiation because of the repo file. */
9483 /* If we've already instantiated the template, just return now. */
9486 }
9488 {
9491 }
9493 {
9496 }
9502 ;
9504 {
9508 }
9509 else
9511 storage);
9518 }
9520 void
9522 tree t;
9524 {
9530 {
9533 }
9534 }
9536 /* Perform an explicit instantiation of template class T. STORAGE, if
9537 non-null, is the RID for extern, inline or static. COMPLAIN is
9538 non-zero if this is called from the parser, zero if called recursively,
9539 since the standard is unclear (as detailed below). */
9541 void
9544 tsubst_flags_t complain;
9545 {
9554 {
9557 }
9561 /* With -fexternal-templates, explicit instantiations are treated the same
9562 as implicit ones. */
9567 {
9570 t);
9572 }
9575 {
9586 else
9587 {
9589 storage);
9591 }
9592 }
9595 {
9596 /* [temp.spec]
9598 No program shall both explicitly instantiate and explicitly
9599 specialize a template. */
9601 {
9604 }
9606 }
9608 {
9609 /* [temp.spec]
9611 No program shall explicitly instantiate any template more
9612 than once.
9614 If CLASSTYPE_INTERFACE_ONLY, then the first explicit instantiation
9615 was `extern'. If EXTERN_P then the second is. If -frepo, chances
9616 are we already got marked as an explicit instantiation because of the
9617 repo file. All these cases are OK. */
9622 /* If we've already instantiated the template, just return now. */
9625 }
9633 {
9634 tree tmp;
9636 /* In contrast to implicit instantiation, where only the
9637 declarations, and not the definitions, of members are
9638 instantiated, we have here:
9640 [temp.explicit]
9642 The explicit instantiation of a class template specialization
9643 implies the instantiation of all of its members not
9644 previously explicitly specialized in the translation unit
9645 containing the explicit instantiation.
9647 Of course, we can't instantiate member template classes, since
9648 we don't have any arguments for them. Note that the standard
9649 is unclear on whether the instantiation of the members are
9650 *explicit* instantiations or not. We choose to be generous,
9651 and not set DECL_EXPLICIT_INSTANTIATION. Therefore, we allow
9652 the explicit instantiation of a class where some of the members
9653 have no definition in the current translation unit. */
9659 {
9664 }
9668 {
9673 }
9679 }
9680 }
9682 /* Given a function DECL, which is a specialization of TMPL, modify
9683 DECL to be a re-instantiation of TMPL with the same template
9684 arguments. TMPL should be the template into which tsubst'ing
9685 should occur for DECL, not the most general template.
9687 One reason for doing this is a scenario like this:
9689 template <class T>
9690 void f(const T&, int i);
9692 void g() { f(3, 7); }
9694 template <class T>
9695 void f(const T& t, const int i) { }
9697 Note that when the template is first instantiated, with
9698 instantiate_template, the resulting DECL will have no name for the
9699 first parameter, and the wrong type for the second. So, when we go
9700 to instantiate the DECL, we regenerate it. */
9702 static void
9704 tree decl;
9705 tree tmpl;
9706 {
9707 /* The most general version of TMPL. */
9708 tree gen_tmpl;
9709 /* The arguments used to instantiate DECL, from the most general
9710 template. */
9711 tree args;
9712 tree code_pattern;
9713 tree new_decl;
9719 /* Unregister the specialization so that when we tsubst we will not
9720 just return DECL. We don't have to unregister DECL from TMPL
9721 because if would only be registered there if it were a partial
9722 instantiation of a specialization, which it isn't: it's a full
9723 instantiation. */
9727 /* If the DECL was not unregistered then something peculiar is
9728 happening: we created a specialization but did not call
9729 register_specialization for it. */
9733 /* Make sure that we can see identifiers, and compute access
9734 correctly, for the class members used in the declaration of
9735 this static variable. */
9738 /* Do the substitution to get the new declaration. */
9742 {
9743 /* Set up DECL_INITIAL, since tsubst doesn't. */
9747 /* Pop the class context we pushed above. */
9749 }
9751 {
9752 /* Convince duplicate_decls to use the DECL_ARGUMENTS from the
9753 new decl. */
9755 /* And don't complain about a duplicate definition. */
9757 }
9759 /* The immediate parent of the new template is still whatever it was
9760 before, even though tsubst sets DECL_TI_TEMPLATE up as the most
9761 general template. We also reset the DECL_ASSEMBLER_NAME since
9762 tsubst always calculates the name as if the function in question
9763 were really a template instance, and sometimes, with friend
9764 functions, this is not so. See tsubst_friend_function for
9765 details. */
9771 /* Call duplicate decls to merge the old and new declarations. */
9774 /* Now, re-register the specialization. */
9776 }
9778 /* Produce the definition of D, a _DECL generated from a template. If
9779 DEFER_OK is non-zero, then we don't have to actually do the
9780 instantiation now; we just have to do it sometime. */
9782 tree
9784 tree d;
9786 {
9789 tree td;
9790 tree code_pattern;
9791 tree spec;
9792 tree gen_tmpl;
9798 /* This function should only be used to instantiate templates for
9799 functions and static member variables. */
9803 /* Don't instantiate cloned functions. Instead, instantiate the
9804 functions they cloned. */
9809 /* D has already been instantiated. It might seem reasonable to
9810 check whether or not D is an explicit instantiation, and, if so,
9811 stop here. But when an explicit instantiation is deferred
9812 until the end of the compilation, DECL_EXPLICIT_INSTANTIATION
9813 is set, even though we still need to do the instantiation. */
9816 /* If we already have a specialization of this declaration, then
9817 there's no reason to instantiate it. Note that
9818 retrieve_specialization gives us both instantiations and
9819 specializations, so we must explicitly check
9820 DECL_TEMPLATE_SPECIALIZATION. */
9826 /* This needs to happen before any tsubsting. */
9832 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
9833 for the instantiation. This is not always the most general
9834 template. Consider, for example:
9836 template <class T>
9837 struct S { template <class U> void f();
9838 template <> void f<int>(); };
9840 and an instantiation of S<double>::f<int>. We want TD to be the
9841 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
9844 more general template. */
9846 /* We must also deal with friend templates. Given:
9848 template <class T> struct S {
9849 template <class U> friend void f() {};
9850 };
9852 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
9853 so far as the language is concerned, but that's still
9854 where we get the pattern for the instantiation from. On
9855 other hand, if the definition comes outside the class, say:
9857 template <class T> struct S {
9858 template <class U> friend void f();
9859 };
9860 template <class U> friend void f() {}
9862 we don't need to look any further. That's what the check for
9863 DECL_INITIAL is for. */
9867 {
9868 /* The present template, TD, should not be a definition. If it
9869 were a definition, we should be using it! Note that we
9870 cannot restructure the loop to just keep going until we find
9871 a template with a definition, since that might go too far if
9872 a specialization was declared, but not defined. */
9877 /* Fetch the more general template. */
9879 }
9885 else
9892 {
9893 /* Let the repository code that this template definition is
9894 available.
9896 The repository doesn't need to know about cloned functions
9897 because they never actually show up in the object file. It
9898 does need to know about the clones; those are the symbols
9899 that the linker will be emitting error messages about. */
9902 {
9903 tree t;
9909 }
9910 else
9914 {
9916 {
9919 }
9921 {
9924 }
9925 else
9927 }
9931 }
9935 /* We should have set up DECL_INITIAL in instantiate_class_template. */
9937 /* Reject all external templates except inline functions. */
9943 /* Defer all other templates, unless we have been explicitly
9944 forbidden from doing so. We restore the source position here
9945 because it's used by add_pending_template. */
9947 {
9953 /* [temp.explicit]
9955 The definition of a non-exported function template, a
9956 non-exported member function template, or a non-exported
9957 member function or static data member of a class template
9958 shall be present in every translation unit in which it is
9959 explicitly instantiated. */
9960 pedwarn
9965 }
9971 /* We're now committed to instantiating this template. Mark it as
9972 instantiated so that recursive calls to instantiate_decl do not
9973 try to instantiate it again. */
9976 /* Regenerate the declaration in case the template has been modified
9977 by a subsequent redeclaration. */
9980 /* We already set the file and line above. Reset them now in case
9981 they changed as a result of calling regenerate_decl_from_template. */
9986 {
9990 else
9991 {
9994 }
9996 }
9998 {
9999 htab_t saved_local_specializations;
10001 /* Save away the current list, in case we are instantiating one
10002 template from within the body of another. */
10005 /* Set up the list of local specializations. */
10007 htab_hash_pointer,
10008 htab_eq_pointer,
10009 NULL);
10011 /* Set up context. */
10014 /* Substitute into the body of the function. */
10018 /* We don't need the local specializations any more. */
10022 /* Finish the function. */
10024 }
10026 /* We're not deferring instantiation any more. */
10032 out:
10041 }
10043 /* Run through the list of templates that we wish we could
10044 instantiate, and instantiate any we can. */
10046 int
10048 {
10054 do
10055 {
10060 {
10066 {
10067 tree fn;
10070 {
10074 fn;
10079 {
10082 }
10083 }
10086 /* If INSTANTIATION has been instantiated, then we don't
10087 need to consider it again in the future. */
10089 else
10090 {
10093 }
10094 }
10095 else
10096 {
10099 {
10103 {
10106 }
10107 }
10111 /* If INSTANTIATION has been instantiated, then we don't
10112 need to consider it again in the future. */
10114 else
10115 {
10118 }
10119 }
10122 }
10124 }
10128 }
10130 /* Substitute ARGVEC into T, which is a list of initializers for
10131 either base class or a non-static data member. The TREE_PURPOSEs
10132 are DECLs, and the TREE_VALUEs are the initializer values. Used by
10133 instantiate_decl. */
10135 static tree
10138 {
10143 {
10144 tree decl;
10145 tree init;
10146 tree val;
10149 NULL_TREE);
10151 NULL_TREE);
10154 ;
10158 else
10163 }
10165 }
10167 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
10169 static void
10171 tree decl;
10172 {
10177 else
10179 }
10181 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
10182 is the instantiation (which should have been created with
10183 start_enum) and ARGS are the template arguments to use. */
10185 static void
10187 tree tag;
10188 tree newtag;
10189 tree args;
10190 {
10191 tree e;
10194 {
10195 tree value;
10197 /* Note that in a template enum, the TREE_VALUE is the
10198 CONST_DECL, not the corresponding INTEGER_CST. */
10201 NULL_TREE);
10203 /* Give this enumeration constant the correct access. */
10206 /* Actually build the enumerator itself. */
10208 }
10213 }
10215 /* DECL is a FUNCTION_DECL that is a template specialization. Return
10216 its type -- but without substituting the innermost set of template
10217 arguments. So, innermost set of template parameters will appear in
10218 the type. If CONTEXTP is non-NULL, then the partially substituted
10219 DECL_CONTEXT (if any) will also be filled in. Similarly, TPARMSP
10220 will be filled in with the substituted template parameters, if it
10221 is non-NULL. */
10223 tree
10225 tree decl;
10228 {
10230 tree fn_type;
10231 tree tmpl;
10232 tree targs;
10233 tree tparms;
10241 /* There should be as many levels of arguments as there are levels
10242 of parameters. */
10250 /* No substitution is necessary. */
10251 ;
10252 else
10253 {
10255 tree partial_args;
10257 /* Replace the innermost level of the TARGS with NULL_TREEs to
10258 let tsubst know not to substitute for those parameters. */
10267 /* Now, do the (partial) substitution to figure out the
10268 appropriate function type. */
10273 /* Substitute into the template parameters to obtain the real
10274 innermost set of parameters. This step is important if the
10275 innermost set of template parameters contains value
10276 parameters whose types depend on outer template parameters. */
10279 }
10287 }
10289 /* Return truthvalue if we're processing a template different from
10290 the last one involved in diagnostics. */
10291 int
10293 {
10295 }
10297 /* Remember current template involved in diagnostics. */
10298 void
10300 {
10302 }
10304 tree
10306 {
10308 }
10310 /* [temp.param] Check that template non-type parm TYPE is of an allowable
10311 type. Return zero for ok, non-zero for disallowed. Issue error and
10312 warning messages under control of COMPLAIN. */
10314 static int
10316 tree type;
10317 tsubst_flags_t complain;
10318 {
10334 type);
10336 }