| blob | 556943c3e55122fd0af78bdece61232bce0f9524 |
1 /* Functions related to building -*- C++ -*- classes and their related objects.
2 Copyright (C) 1987-2024 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
22 /* High-level class interface. */
41 /* Id for dumping the class hierarchy. */
44 /* The number of nested classes being processed. If we are not in the
45 scope of any class, this is zero. */
49 /* In order to deal with nested classes, we keep a stack of classes.
50 The topmost entry is the innermost class, and is the entry at index
51 CURRENT_CLASS_DEPTH */
54 /* The name of the class. */
55 tree name;
57 /* The _TYPE node for the class. */
58 tree type;
60 /* The access specifier pending for new declarations in the scope of
61 this class. */
62 tree access;
64 /* If were defining TYPE, the names used in this class. */
65 splay_tree names_used;
67 /* Nonzero if this class is no longer open, because of a call to
68 push_to_top_level. */
72 struct vtbl_init_data
73 {
74 /* The base for which we're building initializers. */
75 tree binfo;
76 /* The type of the most-derived type. */
77 tree derived;
78 /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
79 unless ctor_vtbl_p is true. */
80 tree rtti_binfo;
81 /* The negative-index vtable initializers built up so far. These
82 are in order from least negative index to most negative index. */
84 /* The binfo for the virtual base for which we're building
85 vcall offset initializers. */
86 tree vbase;
87 /* The functions in vbase for which we have already provided vcall
88 offsets. */
90 /* The vtable index of the next vcall or vbase offset. */
91 tree index;
92 /* Nonzero if we are building the initializer for the primary
93 vtable. */
95 /* Nonzero if we are building the initializer for a construction
96 vtable. */
98 /* True when adding vcall offset entries to the vtable. False when
99 merely computing the indices. */
101 };
103 /* The type of a function passed to walk_subobject_offsets. */
106 /* The stack itself. This is a dynamically resized array. The
107 number of elements allocated is CURRENT_CLASS_STACK_SIZE. */
111 /* The size of the largest empty class seen in this translation unit. */
141 /* Used by find_flexarrays and related functions. */
189 tree *);
198 splay_tree_key k2);
210 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
212 void
214 {
219 else
221 }
223 /* Return a COND_EXPR that executes TRUE_STMT if this execution of the
224 'structor is in charge of 'structing virtual bases, or FALSE_STMT
225 otherwise. */
227 tree
229 {
239 }
241 /* Convert to or from a base subobject. EXPR is an expression of type
242 `A' or `A*', an expression of type `B' or `B*' is returned. To
243 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
244 the B base instance within A. To convert base A to derived B, CODE
245 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
246 In this latter case, A must not be a morally virtual base of B.
247 NONNULL is true if EXPR is known to be non-NULL (this is only
248 needed when EXPR is of pointer type). CV qualifiers are preserved
249 from EXPR. */
251 tree
253 tree expr,
254 tree binfo,
256 tsubst_flags_t complain)
257 {
260 tree probe;
261 tree offset;
262 tree target_type;
264 tree ptr_target_type;
275 {
281 }
292 {
293 /* This can happen when adjust_result_of_qualified_name_lookup can't
294 find a unique base binfo in a call to a member function. We
295 couldn't give the diagnostic then since we might have been calling
296 a static member function, so we do it now. In other cases, eg.
297 during error recovery (c++/71979), we may not have a base at all. */
299 {
303 }
305 }
312 /* Nothing to do. */
316 {
318 {
320 {
323 "pointer to derived class %qT because the base is "
325 else
329 }
330 else
331 {
337 else
341 }
342 }
344 }
347 || processing_template_decl
350 /* For a non-pointer simple base reference, express it as a COMPONENT_REF
351 without taking its address (and so causing lambda capture, 91933). */
356 {
358 /* This must happen before the call to save_expr. */
360 }
361 else
367 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
368 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
369 expression returned matches the input. */
370 target_type = cp_build_qualified_type
374 /* Do we need to look in the vtable for the real offset? */
377 /* Don't bother with the calculations inside sizeof; they'll ICE if the
378 source type is incomplete and the pointer value doesn't matter. In a
379 template (even in instantiate_non_dependent_expr), we don't have vtables
380 set up properly yet, and the value doesn't matter there either; we're
381 just interested in the result of overload resolution. */
383 {
386 }
389 {
395 }
397 /* If we're in an NSDMI, we don't have the full constructor context yet
398 that we need for converting to a virtual base, so just build a stub
399 CONVERT_EXPR and expand it later in bot_replace. */
402 {
406 }
408 /* Do we need to check for a null pointer? */
410 {
411 /* If we know the conversion will not actually change the value
412 of EXPR, then we can avoid testing the expression for NULL.
413 We have to avoid generating a COMPONENT_REF for a base class
414 field, because other parts of the compiler know that such
415 expressions are always non-NULL. */
419 }
421 /* Protect against multiple evaluation if necessary. */
425 /* Store EXPR and build the real null test just before returning. */
429 /* If this is a simple base reference, express it as a COMPONENT_REF. */
431 /* We don't build base fields for empty bases, and they aren't very
432 interesting to the optimizers anyway. */
434 {
443 }
446 {
447 /* Going via virtual base V_BINFO. We need the static offset
448 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
449 V_BINFO. That offset is an entry in D_BINFO's vtable. */
450 tree v_offset;
453 {
454 /* In a base member initializer, we cannot rely on the
455 vtable being set up. We have to indirect via the
456 vtt_parm. */
457 tree t;
463 }
464 else
465 {
469 {
474 }
477 }
485 v_offset);
497 /* Negative fixed_type_p means this is a constructor or destructor;
498 virtual base layout is fixed in in-charge [cd]tors, but not in
499 base [cd]tors. */
500 offset = build_if_in_charge
502 v_offset);
503 else
505 }
511 {
516 }
517 else
522 indout:
524 {
528 }
530 out:
532 /* Wrap EXPR in a null test. */
536 }
538 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
539 Perform a derived-to-base conversion by recursively building up a
540 sequence of COMPONENT_REFs to the appropriate base fields. */
542 static tree
544 {
547 tree field;
550 {
551 tree temp;
555 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
556 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
557 an lvalue in the front end; only _DECLs and _REFs are lvalues
558 in the back end. */
564 }
566 /* Recurse. */
571 /* Is this the base field created by build_base_field? */
575 /* If we're looking for a field in the most-derived class,
576 also check the field offset; we can have two base fields
577 of the same type if one is an indirect virtual base and one
578 is a direct non-virtual base. */
582 {
583 /* We don't use build_class_member_access_expr here, as that
584 has unnecessary checks, and more importantly results in
585 recursive calls to dfs_walk_once. */
591 /* Mark the expression const or volatile, as appropriate.
592 Even though we've dealt with the type above, we still have
593 to mark the expression itself. */
600 }
602 /* Didn't find the base field?!? */
604 }
606 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
607 type is a class type or a pointer to a class type. In the former
608 case, TYPE is also a class type; in the latter it is another
609 pointer type. If CHECK_ACCESS is true, an error message is emitted
610 if TYPE is inaccessible. If OBJECT has pointer type, the value is
611 assumed to be non-NULL. */
613 tree
615 tsubst_flags_t complain)
616 {
617 tree binfo;
618 tree object_type;
621 {
624 }
625 else
634 }
636 /* EXPR is an expression with unqualified class type. BASE is a base
637 binfo of that class type. Returns EXPR, converted to the BASE
638 type. This function assumes that EXPR is the most derived class;
639 therefore virtual bases can be found at their static offsets. */
641 tree
643 {
644 tree expr_type;
648 {
649 /* If this is a non-empty base, use a COMPONENT_REF. */
653 /* We use fold_build2 and fold_convert below to simplify the trees
654 provided to the optimizers. It is not safe to call these functions
655 when processing a template because they do not handle C++-specific
656 trees. */
664 }
667 }
669 /* True IFF EXPR is a reference to an empty base class "subobject", as built in
670 convert_to_base_statically. We look for the result of the fold_convert
671 call, a NOP_EXPR from one pointer type to another, where the target is an
672 empty base of the original type. */
674 bool
676 {
695 }
696 \f
697 tree
699 {
703 /* Can happen in case of duplicate base types (c++/59082). */
707 /* First, convert to the requested type. */
712 /* Second, the requested type may not be the owner of its own vptr.
713 If not, convert to the base class that owns it. We cannot use
714 convert_to_base here, because VCONTEXT may appear more than once
715 in the inheritance hierarchy of TYPE, and thus direct conversion
716 between the types may be ambiguous. Following the path back up
717 one step at a time via primary bases avoids the problem. */
721 {
724 }
727 }
729 /* Given an object INSTANCE, return an expression which yields the
730 vtable element corresponding to INDEX. There are many special
731 cases for INSTANCE which we take care of here, mainly to avoid
732 creating extra tree nodes when we don't have to. */
734 tree
736 {
737 tree aref;
740 /* Try to figure out what a reference refers to, and
741 access its virtual function table directly. */
749 {
754 }
763 }
765 /* Given a stable object pointer INSTANCE_PTR, return an expression which
766 yields a function pointer corresponding to vtable element INDEX. */
768 tree
770 {
771 tree aref;
775 /* When using function descriptors, the address of the
776 vtable entry is treated as a function pointer. */
781 /* Remember this as a method reference, for later devirtualization. */
786 }
788 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
789 for the given TYPE. */
791 static tree
793 {
795 }
797 /* DECL is an entity associated with TYPE, like a virtual table or an
798 implicitly generated constructor. Determine whether or not DECL
799 should have external or internal linkage at the object file
800 level. This routine does not deal with COMDAT linkage and other
801 similar complexities; it simply sets TREE_PUBLIC if it possible for
802 entities in other translation units to contain copies of DECL, in
803 the abstract. */
805 void
807 {
810 }
812 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
813 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
814 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
816 static tree
818 {
819 tree decl;
822 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
823 now to avoid confusion in mangle_decl. */
834 /* The vtable has not been defined -- yet. */
838 /* Mark the VAR_DECL node representing the vtable itself as a
839 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
840 is rather important that such things be ignored because any
841 effort to actually generate DWARF for them will run into
842 trouble when/if we encounter code like:
844 #pragma interface
845 struct S { virtual void member (); };
847 because the artificial declaration of the vtable itself (as
848 manufactured by the g++ front end) will say that the vtable is
849 a static member of `S' but only *after* the debug output for
850 the definition of `S' has already been output. This causes
851 grief because the DWARF entry for the definition of the vtable
852 will try to refer back to an earlier *declaration* of the
853 vtable as a static member of `S' and there won't be one. We
854 might be able to arrange to have the "vtable static member"
855 attached to the member list for `S' before the debug info for
856 `S' get written (which would solve the problem) but that would
857 require more intrusive changes to the g++ front end. */
861 }
863 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
864 or even complete. If this does not exist, create it. If COMPLETE is
865 nonzero, then complete the definition of it -- that will render it
866 impossible to actually build the vtable, but is useful to get at those
867 which are known to exist in the runtime. */
869 tree
871 {
872 tree decl;
881 {
884 }
887 }
889 /* Build the primary virtual function table for TYPE. If BINFO is
890 non-NULL, build the vtable starting with the initial approximation
891 that it is the same as the one which is the head of the association
892 list. Returns a nonzero value if a new vtable is actually
893 created. */
895 static int
897 {
898 tree decl;
899 tree virtuals;
904 {
906 /* We have already created a vtable for this base, so there's
907 no need to do it again. */
914 }
915 else
916 {
919 }
921 /* Initialize the association list for this type, based
922 on our first approximation. */
927 }
929 /* Give BINFO a new virtual function table which is initialized
930 with a skeleton-copy of its original initialization. The only
931 entry that changes is the `delta' entry, so we can really
932 share a lot of structure.
934 FOR_TYPE is the most derived type which caused this table to
935 be needed.
937 Returns nonzero if we haven't met BINFO before.
939 The order in which vtables are built (by calling this function) for
940 an object must remain the same, otherwise a binary incompatibility
941 can result. */
943 static int
945 {
947 /* We already created a vtable for this base. There's no need to
948 do it again. */
951 /* Remember that we've created a vtable for this BINFO, so that we
952 don't try to do so again. */
955 /* Make fresh virtual list, so we can smash it later. */
958 /* Secondary vtables are laid out as part of the same structure as
959 the primary vtable. */
962 }
964 /* Create a new vtable for BINFO which is the hierarchy dominated by
965 T. Return nonzero if we actually created a new vtable. */
967 static int
969 {
971 /* In this case, it is *type*'s vtable we are modifying. We start
972 with the approximation that its vtable is that of the
973 immediate base class. */
975 else
976 /* This is our very own copy of `basetype' to play with. Later,
977 we will fill in all the virtual functions that override the
978 virtual functions in these base classes which are not defined
979 by the current type. */
981 }
983 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
984 (which is in the hierarchy dominated by T) list FNDECL as its
985 BV_FN. DELTA is the required constant adjustment from the `this'
986 pointer where the vtable entry appears to the `this' required when
987 the function is actually called. */
989 static void
991 tree binfo,
992 tree fndecl,
993 tree delta,
995 {
996 tree v;
1002 {
1003 /* We need a new vtable for BINFO. */
1005 {
1006 /* If we really did make a new vtable, we also made a copy
1007 of the BINFO_VIRTUALS list. Now, we have to find the
1008 corresponding entry in that list. */
1013 }
1018 }
1019 }
1021 \f
1022 /* Check if the object parameter of an iobj member function corresponds to
1023 another parameter type. CONTEXT is the class that the implicit object
1024 parameter is considered to refer to. */
1026 bool
1028 {
1031 /* If the iobj member function was introduced with a using declaration, the
1032 type of its object parameter is considered to be that of the class it was
1033 introduced into.
1035 [over.match.funcs.general.4]
1036 For non-conversion functions that are implicit object member
1037 functions nominated by a using-declaration in a derived class, the
1038 function is considered to be a member of the derived class for the purpose
1039 of defining the type of the implicit object parameter.
1041 Unfortunately, because of this rule, we can't just compare the xobj member
1042 function's DECL_CONTEXT to its object parameter.
1044 struct S;
1046 struct B {
1047 int f(this S&) { return 5; }
1048 };
1050 struct S : B {
1051 using B::f;
1052 int f() { return 10; }
1053 };
1055 The using declaration does not change the object parameter of B::f as it
1056 is an xobj member function. However, its object parameter still
1057 corresponds to S::f as it was declared with an object parameter of type
1058 S const&. The DECL_CONTEXT of B::f is B, so if we compare the type of the
1059 object parameter to that, it will not match. If we naively assume a
1060 different type from the DECL_CONTEXT for an xobj parameter means that the
1061 object parameters do not correspond, then the object parameters in the
1062 above example will be considered non-corresponding.
1064 As a result of this, B::f would incorrectly not be discarded, causing an
1065 ambiguity when f is called on an object of type S.
1067 This also impacts member functions with constraints as in the following
1068 example.
1070 template<typename = void>
1071 struct S;
1073 template<typename = void>
1074 struct B {
1075 int f(this S<>&) requires true { return 5; }
1076 };
1078 template<typename>
1079 struct S : B<> {
1080 using B<>::f;
1081 int f() { return 10; }
1082 };
1084 Once again, if we compare the DECL_CONTEXT of B<>::f to it's xobj
1085 parameter, it would not match. If the object parameters do not
1086 correspond, constraints are not taken into account, so in this example we
1087 would (probably) get an ambiguous lookup instead of correctly picking
1088 B<>::f.
1090 Because of this caveat, we must actually compare the type of the iobj
1091 parameter to the type of the xobj parameter, shortcuts will have these
1092 edge cases.
1094 Aside from the more complex reasons above, this logic also implicitly
1095 handles xobj parameters of pointer type, we don't have to explicitly
1096 check for that case. */
1102 /* We don't get to bail yet even if we have a by-value xobj parameter,
1103 a by-value xobj parameter can correspond to an iobj parameter provided the
1104 iobj member function is not declared with a reference qualifier.
1106 From this point on, we know we are dealing with an xobj parameter that has
1107 an object parameter of the same type as the class it was declared in.
1108 We still don't know if we have a reference or by-value parameter yet
1109 though. */
1112 /* We only care about cv qualifiers when determining correspondence. */
1116 /* We need to ignore the ref qualifier of the xobj parameter if the iobj
1117 member function lacks a ref qualifier.
1119 [basic.scope.scope.3]
1120 Two non-static member functions have corresponding object parameters if:
1121 -- exactly one is an implicit object member function with no ref-qualifier
1122 and the types of their object parameters ([dcl.fct]), after removing
1123 top-level references, are the same, or
1124 -- their object parameters have the same type.
1126 The cv qualifiers of a by-value parameter are supposed to be discarded, so
1127 we ignore them.
1129 [dcl.fct.5]
1130 After producing the list of parameter types, any top-level cv-qualifiers
1131 modifying a parameter type are deleted when forming the function type.
1133 However, they still need to be taken into account when our xobj parameter
1134 is a reference that is being ignored (according to [basic.scope.scope.3]
1135 quoted above), but when we are actually dealing with a by-value xobj
1136 parameter we can proceed following this table.
1137 | iobj | xobj | equal |
1138 | none | none | X |
1139 | none | c | X |
1140 | none | v | X |
1141 | none | cv | X |
1142 | c | none | O |
1143 | c | c | O |
1144 | c | v | O |
1145 | c | cv | O |
1146 | v | none | O |
1147 | v | c | O |
1148 | v | v | O |
1149 | v | cv | O |
1150 | cv | none | O |
1151 | cv | c | O |
1152 | cv | v | O |
1153 | cv | cv | O |
1155 Additionally, if the iobj member function is ref qualified, we aren't
1156 ignoring the ref qualifier of the iobj parameter, so we can't be dealing
1157 with correspondence in that case either.
1159 So to recap, if we have a by-value xobj parameter, we know for sure that
1160 we aren't dealing with corresponding object parameters if the iobj member
1161 function has any cv-ref qualifiers. The only case where we might still be
1162 dealing with corresponding object parameters is when the iobj member
1163 function lacks any cv-ref qualification. */
1165 {
1168 }
1169 else
1170 {
1171 /* We are dealing with an xobj parameter that is a reference now, but due
1172 to [basic.scope.scope.3] we need to ignore its ref qual. */
1180 /* Even if we are ignoring the reference qualifier, the xobj parameter
1181 was still a reference so we still take the cv qualifiers into
1182 account. */
1183 cp_cv_quals const xobj_cv_quals
1186 /* Finally, if the qualifications don't match exactly, the object
1187 parameters don't correspond. */
1191 }
1192 /* If we got past everything else, the object parameters of fn1 and fn2
1193 definitely correspond. */
1195 }
1197 /* True if FN and METHOD have corresponding object parms per
1198 [basic.scope.scope], or if one of them is a static member function (which
1199 are considered to have an object parm that corresponds to any other).
1200 CONTEXT is the class that an implicit object member function is considered
1201 to be a member of for the purpose of this comparison, per
1202 [over.match.funcs]. */
1204 bool
1206 {
1210 /* Compare the quals on the 'this' parm. Don't compare
1211 the whole types, as used functions are treated as
1212 coming from the using class in overload resolution. */
1215 {
1216 /* Either both or neither need to be ref-qualified for
1217 differing quals to allow overloading. */
1224 }
1225 /* Treat a static member function as corresponding to any object parm. */
1228 /* Handle special correspondence rules for xobj vs xobj and xobj vs iobj
1229 member function declarations.
1230 We don't worry about static member functions here. */
1233 {
1235 {
1237 };
1238 /* We skip the object parameter below, check it here instead of
1239 making changes to that code. */
1244 }
1245 else
1246 {
1252 }
1255 }
1257 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
1258 METHOD is being injected via a using_decl. Returns true if the
1259 method could be added to the method vec. */
1261 bool
1263 {
1272 /* See below. */
1275 /* Check to see if we've already got this method. */
1277 {
1283 /* Two using-declarations can coexist, we'll complain about ambiguity in
1284 overload resolution. */
1286 /* Except handle inherited constructors specially. */
1288 {
1290 /* Don't add the same one twice. */
1293 }
1295 /* [over.load] Member function declarations with the
1296 same name and the same parameter types cannot be
1297 overloaded if any of them is a static member
1298 function declaration.
1300 [over.load] Member function declarations with the same name and
1301 the same parameter-type-list as well as member function template
1302 declarations with the same name, the same parameter-type-list, and
1303 the same template parameter lists cannot be overloaded if any of
1304 them, but not all, have a ref-qualifier.
1306 [namespace.udecl] When a using-declaration brings names
1307 from a base class into a derived class scope, member
1308 functions in the derived class override and/or hide member
1309 functions with the same name and parameter types in a base
1310 class (rather than conflicting). */
1320 /* Templates and conversion ops must match return types. */
1325 /* For templates, the template parameters must be identical. */
1327 {
1334 }
1343 /* Bring back parameters omitted from an inherited ctor. The
1344 method and the function can have different omittedness. */
1348 parms2 = (FUNCTION_FIRST_USER_PARMTYPE
1355 {
1357 /* We can't check satisfaction in dependent context, wait until
1358 the class is instantiated. */
1366 /* Member function templates and non-special member functions
1367 coexist if they are not equivalently constrained. A member
1368 function is not hidden by an inherited constructor. */
1371 /* P0848: For special member functions, deleted, unsatisfied, or
1372 less constrained overloads are ineligible. We implement this
1373 by removing them from CLASSTYPE_MEMBER_VEC. Destructors don't
1374 use the notion of eligibility, and the selected destructor can
1375 be deleted, but removing unsatisfied or less constrained
1376 overloads has the same effect as overload resolution. */
1386 else
1389 /* Leave FN in the method vec, discard METHOD. */
1392 {
1393 /* Remove FN, add METHOD. */
1396 }
1397 else
1398 /* Let them coexist for now. */
1400 }
1402 /* If these are versions of the same function, process and
1403 move on. */
1409 {
1411 /* Defer to the other function. */
1417 {
1419 {
1420 /* Inheriting the same constructor along different
1421 paths, combine them. */
1422 SET_DECL_INHERITED_CTOR
1425 /* And discard the new one. */
1427 }
1428 else
1429 /* Inherited ctors can coexist until overload
1430 resolution. */
1432 }
1439 basef);
1441 }
1444 /* Defer to the local function. */
1447 || (flag_new_inheriting_ctors
1449 {
1450 /* Remove the inherited function. */
1453 }
1454 else
1455 {
1461 }
1462 }
1473 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1479 }
1481 /* Subroutines of finish_struct. */
1483 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1484 legit, otherwise return 0. */
1486 static int
1488 {
1489 tree elem;
1497 {
1499 {
1503 else
1506 }
1507 else
1508 {
1509 /* They're changing the access to the same thing they changed
1510 it to before. That's OK. */
1511 ;
1512 }
1513 }
1514 else
1515 {
1517 tf_warning_or_error);
1520 }
1522 }
1524 /* Return the access node for DECL's access in its enclosing class. */
1526 tree
1528 {
1532 }
1534 /* If DECL is a non-dependent using of non-ctor function members, push them
1535 and return true, otherwise return false. Called from
1536 finish_member_declaration. */
1538 bool
1540 {
1547 /* Add the functions to CLASSTYPE_MEMBER_VEC so that overload resolution
1548 works within the class body. */
1550 {
1552 /* Inheriting constructors are handled separately. */
1560 /* If add_method returns false because f was already declared, look
1561 for a duplicate using-declaration. */
1562 else
1567 {
1570 }
1571 }
1573 }
1575 /* Process the USING_DECL, which is a member of T. */
1577 static void
1579 {
1587 /* Handled in maybe_push_used_methods. */
1592 tf_warning_or_error);
1594 {
1599 else
1601 }
1604 ;
1606 {
1613 }
1615 {
1622 }
1627 /* Make type T see field decl FDECL with access ACCESS. */
1629 {
1630 /* C++20 using enum can import non-inherited enumerators into class
1631 scope. We implement that by making a copy of the CONST_DECL for which
1632 CONST_DECL_USING_P is true. */
1639 /* We emitted debug info for the USING_DECL above; make sure we don't
1640 also emit anything for this clone. */
1645 }
1646 else
1648 }
1649 \f
1650 /* Data structure for find_abi_tags_r, below. */
1652 struct abi_tag_data
1653 {
1657 };
1659 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1660 in the context of P. TAG can be either an identifier (the DECL_NAME of
1661 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1663 static void
1665 {
1667 {
1669 {
1670 /* We're collecting tags from template arguments or from
1671 the type of a variable or function return type. */
1674 /* Don't inherit this tag multiple times. */
1678 {
1679 /* Tags inherited from type template arguments are only used
1680 to avoid warnings. */
1683 }
1684 /* For functions and variables we want to warn, too. */
1685 }
1687 /* Otherwise we're diagnosing missing tags. */
1689 {
1690 auto_diagnostic_group d;
1695 }
1697 {
1698 auto_diagnostic_group d;
1702 }
1704 {
1705 auto_diagnostic_group d;
1710 }
1711 else
1712 {
1713 auto_diagnostic_group d;
1717 {
1721 }
1722 }
1723 }
1724 }
1726 /* Find all the ABI tags in the attribute list ATTR and either call
1727 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1729 static void
1731 {
1738 {
1743 else
1745 }
1746 }
1748 /* Find all the ABI tags on T and its enclosing scopes and either call
1749 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1751 static void
1753 {
1755 {
1756 tree attr;
1758 {
1761 }
1762 else
1763 {
1766 }
1768 }
1769 }
1771 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1772 types with ABI tags, add the corresponding identifiers to the VEC in
1773 *DATA and set IDENTIFIER_MARKED. */
1775 static tree
1777 {
1779 /* Tell cp_walk_subtrees to look though typedefs. [PR98481] */
1785 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1786 anyway, but let's make sure of it. */
1794 }
1796 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1797 IDENTIFIER_MARKED on its ABI tags. */
1799 static tree
1801 {
1803 /* Tell cp_walk_subtrees to look though typedefs. */
1809 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1810 anyway, but let's make sure of it. */
1818 }
1820 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1821 scopes. */
1823 static void
1825 {
1828 {
1831 {
1832 /* Template arguments are part of the signature. */
1835 {
1838 }
1839 }
1841 /* A function's parameter types are part of the signature, so
1842 we don't need to inherit any tags that are also in them. */
1847 }
1848 }
1850 /* Check that T has all the ABI tags that subobject SUBOB has, or
1851 warn if not. If T is a (variable or function) declaration, also
1852 return any missing tags, and add them to T if JUST_CHECKING is false. */
1854 static tree
1856 {
1864 /* No need to worry about things local to this TU. */
1880 {
1883 }
1884 else
1885 {
1889 else
1892 }
1897 }
1899 /* Check that DECL has all the ABI tags that are used in parts of its type
1900 that are not reflected in its mangled name. */
1902 void
1904 {
1911 }
1913 /* Return any ABI tags that are used in parts of the type of DECL
1914 that are not reflected in its mangled name. This function is only
1915 used in backward-compatible mangling for ABI <11. */
1917 tree
1919 {
1923 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1924 that we can use this function for setting need_abi_warning
1925 regardless of the current flag_abi_version. */
1928 else
1930 }
1932 void
1934 {
1944 {
1947 {
1951 }
1952 }
1954 // If we found some tags on our template arguments, add them to our
1955 // abi_tag attribute.
1957 {
1961 else
1964 }
1967 }
1969 /* Return true, iff class T has a non-virtual destructor that is
1970 accessible from outside the class heirarchy (i.e. is public, or
1971 there's a suitable friend. */
1973 static bool
1975 {
1978 /* An implicitly declared destructor is always public. And,
1979 if it were virtual, we would have created it by now. */
1994 }
1996 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1997 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1998 properties of the bases. */
2000 static void
2004 {
2008 tree base_binfo;
2009 tree binfo;
2019 {
2028 /* If any base class is non-literal, so is the derived class. */
2032 /* If the base class doesn't have copy constructors or
2033 assignment operators that take const references, then the
2034 derived class cannot have such a member automatically
2035 generated. */
2044 /* A virtual base does not effect nearly emptiness. */
2045 ;
2047 {
2049 /* And if there is more than one nearly empty base, then the
2050 derived class is not nearly empty either. */
2052 else
2053 /* Remember we've seen one. */
2055 }
2057 /* If the base class is not empty or nearly empty, then this
2058 class cannot be nearly empty. */
2061 /* A lot of properties from the bases also apply to the derived
2062 class. */
2079 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
2082 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
2088 /* A standard-layout class is a class that:
2089 ...
2090 * has no non-standard-layout base classes, */
2093 {
2094 tree basefield;
2095 /* ...has no base classes of the same type as the first non-static
2096 data member... */
2098 && (same_type_ignoring_top_level_qualifiers_p
2101 /* DR 1813:
2102 ...has at most one base class subobject of any given type... */
2105 else
2106 /* ...has all non-static data members and bit-fields in the class
2107 and its base classes first declared in the same class. */
2113 {
2116 else
2119 }
2120 }
2122 /* Don't bother collecting tm attributes if transactional memory
2123 support is not enabled. */
2125 {
2129 }
2132 }
2134 /* If one of the base classes had TM attributes, and the current class
2135 doesn't define its own, then the current class inherits one. */
2137 {
2140 }
2141 }
2143 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
2144 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
2145 that have had a nearly-empty virtual primary base stolen by some
2146 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
2147 T. */
2149 static void
2151 {
2155 tree base_binfo;
2157 /* Determine the primary bases of our bases. */
2160 {
2163 /* See if we're the non-virtual primary of our inheritance
2164 chain. */
2166 {
2173 /* We are the primary binfo. */
2175 }
2176 /* Determine if we have a virtual primary base, and mark it so.
2177 */
2179 {
2183 /* Someone already claimed this base. */
2185 else
2186 {
2187 tree delta;
2192 /* A virtual binfo might have been copied from within
2193 another hierarchy. As we're about to use it as a
2194 primary base, make sure the offsets match. */
2202 }
2203 }
2204 }
2206 /* First look for a dynamic direct non-virtual base. */
2208 {
2212 {
2215 }
2216 }
2218 /* A "nearly-empty" virtual base class can be the primary base
2219 class, if no non-virtual polymorphic base can be found. Look for
2220 a nearly-empty virtual dynamic base that is not already a primary
2221 base of something in the hierarchy. If there is no such base,
2222 just pick the first nearly-empty virtual base. */
2228 {
2230 {
2231 /* Found one that is not primary. */
2234 }
2236 /* Remember the first candidate. */
2238 }
2240 found:
2241 /* If we've got a primary base, use it. */
2243 {
2248 /* We are stealing a primary base. */
2252 {
2253 tree delta;
2256 /* A virtual binfo might have been copied from within
2257 another hierarchy. As we're about to use it as a primary
2258 base, make sure the offsets match. */
2263 }
2270 }
2271 }
2273 /* Update the variant types of T. */
2275 void
2277 {
2282 variant;
2284 {
2285 /* These fields are in the _TYPE part of the node, not in
2286 the TYPE_LANG_SPECIFIC component, so they are not shared. */
2297 /* Copy whatever these are holding today. */
2307 {
2310 }
2315 }
2316 }
2318 /* KLASS is a class that we're applying may_alias to after the body is
2319 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
2320 canonical type(s) will be implicitly updated. */
2322 static void
2324 {
2333 }
2335 /* Early variant fixups: we apply attributes at the beginning of the class
2336 definition, and we need to fix up any variants that have already been
2337 made via elaborated-type-specifier so that check_qualified_type works. */
2339 void
2341 {
2342 tree variants;
2357 variants;
2359 {
2360 /* These are the two fields that check_qualified_type looks at and
2361 are affected by attributes. */
2366 else
2372 }
2373 }
2374 \f
2375 /* Set memoizing fields and bits of T (and its variants) for later
2376 use. */
2378 static void
2380 {
2381 /* Fix up variants (if any). */
2385 /* For a class w/o baseclasses, 'finish_struct' has set
2386 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2387 Similarly for a class whose base classes do not have vtables.
2388 When neither of these is true, we might have removed abstract
2389 virtuals (by providing a definition), added some (by declaring
2390 new ones), or redeclared ones from a base class. We need to
2391 recalculate what's really an abstract virtual at this point (by
2392 looking in the vtables). */
2395 /* If this type has a copy constructor or a destructor, force its
2396 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2397 nonzero. This will cause it to be passed by invisible reference
2398 and prevent it from being returned in a register. */
2401 {
2402 tree variants;
2405 {
2408 }
2409 }
2410 }
2412 /* Issue warnings about T having private constructors, but no friends,
2413 and so forth.
2415 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2416 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2417 non-private static member functions. */
2419 static void
2421 {
2427 /* If the class has friends, those entities might create and
2428 access instances, so we should not warn. */
2431 /* We will have warned when the template was declared; there's
2432 no need to warn on every instantiation. */
2434 /* There's no reason to even consider warning about this
2435 class. */
2438 /* We only issue one warning, if more than one applies, because
2439 otherwise, on code like:
2441 class A {
2442 // Oops - forgot `public:'
2443 A();
2444 A(const A&);
2445 ~A();
2446 };
2448 we warn several times about essentially the same problem. */
2450 /* Check to see if all (non-constructor, non-destructor) member
2451 functions are private. (Since there are no friends or
2452 non-private statics, we can't ever call any of the private member
2453 functions.) */
2462 /* We're not interested in compiler-generated methods; they don't
2465 {
2467 /* A non-private static member function is just like a
2468 friend; it can create and invoke private member
2469 functions, and be accessed without a class
2470 instance. */
2474 /* Keep searching for a static member function. */
2475 }
2480 {
2481 /* There are no non-private methods, and there's at least one
2482 private member function that isn't a constructor or
2483 destructor. (If all the private members are
2484 constructors/destructors we want to use the code below that
2485 issues error messages specifically referring to
2486 constructors/destructors.) */
2492 {
2495 }
2497 {
2501 }
2502 }
2504 /* Even if some of the member functions are non-private, the class
2505 won't be useful for much if all the constructors or destructors
2506 are private: such an object can never be created or destroyed. */
2509 {
2512 t);
2514 }
2516 /* Warn about classes that have private constructors and no friends. */
2518 /* Implicitly generated constructors are always public. */
2520 {
2523 /* If a non-template class does not define a copy
2524 constructor, one is defined for it, enabling it to avoid
2525 this warning. For a template class, this does not
2526 happen, and so we would normally get a warning on:
2528 template <class T> class C { private: C(); };
2530 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2531 complete non-template or fully instantiated classes have this
2532 flag set. */
2535 else
2540 /* Ideally, we wouldn't count any constructor that takes
2541 an argument of the class type as a parameter, because
2542 such things cannot be used to construct an instance of
2543 the class unless you already have one. */
2545 else
2546 {
2549 }
2552 {
2554 "%q#T only defines private constructors and has "
2561 }
2562 }
2563 }
2565 /* Make BINFO's vtable have N entries, including RTTI entries,
2566 vbase and vcall offsets, etc. Set its type and call the back end
2567 to lay it out. */
2569 static void
2571 {
2572 tree atype;
2573 tree vtable;
2578 /* We may have to grow the vtable. */
2581 {
2585 }
2586 }
2588 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2589 have the same signature. */
2591 int
2593 {
2594 /* One destructor overrides another if they are the same kind of
2595 destructor. */
2599 /* But a non-destructor never overrides a destructor, nor vice
2600 versa, nor do different kinds of destructors override
2601 one-another. For example, a complete object destructor does not
2602 override a deleting destructor. */
2611 {
2619 }
2621 }
2623 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2624 subobject. */
2626 static bool
2628 {
2629 tree probe;
2632 {
2636 /* If we meet a virtual base, we can't follow the inheritance
2637 any more. See if the complete type of DERIVED contains
2638 such a virtual base. */
2641 }
2643 }
2646 /* The function for which we are trying to find a final overrider. */
2647 tree fn;
2648 /* The base class in which the function was declared. */
2649 tree declaring_base;
2650 /* The candidate overriders. */
2651 tree candidates;
2652 /* Path to most derived. */
2654 };
2656 /* Add the overrider along the current path to FFOD->CANDIDATES.
2657 Returns true if an overrider was found; false otherwise. */
2659 static bool
2663 {
2664 tree method;
2666 /* If BINFO is not the most derived type, try a more derived class.
2667 A definition there will overrider a definition here. */
2669 {
2670 depth--;
2674 }
2678 {
2681 /* Remove any candidates overridden by this new function. */
2683 {
2684 /* If *CANDIDATE overrides METHOD, then METHOD
2685 cannot override anything else on the list. */
2688 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2691 else
2693 }
2695 /* Add the new function. */
2698 }
2701 }
2703 /* Called from find_final_overrider via dfs_walk. */
2705 static tree
2707 {
2715 }
2717 static tree
2719 {
2724 }
2726 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2727 FN and whose TREE_VALUE is the binfo for the base where the
2728 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2729 DERIVED) is the base object in which FN is declared. */
2731 static tree
2733 {
2734 find_final_overrider_data ffod;
2736 /* Getting this right is a little tricky. This is valid:
2738 struct S { virtual void f (); };
2739 struct T { virtual void f (); };
2740 struct U : public S, public T { };
2742 even though calling `f' in `U' is ambiguous. But,
2744 struct R { virtual void f(); };
2745 struct S : virtual public R { virtual void f (); };
2746 struct T : virtual public R { virtual void f (); };
2747 struct U : public S, public T { };
2749 is not -- there's no way to decide whether to put `S::f' or
2750 `T::f' in the vtable for `R'.
2752 The solution is to look at all paths to BINFO. If we find
2753 different overriders along any two, then there is a problem. */
2757 /* Determine the depth of the hierarchy. */
2766 /* If there was no winner, issue an error message. */
2771 }
2773 /* Return the index of the vcall offset for FN when TYPE is used as a
2774 virtual base. */
2776 static tree
2778 {
2780 tree_pair_p p;
2788 /* There should always be an appropriate index. */
2790 }
2792 /* Given a DECL_VINDEX of a virtual function found in BINFO, return the final
2793 overrider at that index in the vtable. This should only be used when we
2794 know that BINFO is correct for the dynamic type of the object. */
2796 tree
2798 {
2803 /* BINFO_VIRTUALS in a primary base isn't accurate, find the derived
2804 class that actually owns the vtable. */
2808 }
2810 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2811 dominated by T. FN is the old function; VIRTUALS points to the
2812 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2813 of that entry in the list. */
2815 static void
2818 {
2819 tree b;
2820 tree overrider;
2821 tree delta;
2822 tree virtual_base;
2823 tree first_defn;
2829 /* Find the nearest primary base (possibly binfo itself) which defines
2830 this function; this is the class the caller will convert to when
2831 calling FN through BINFO. */
2833 {
2838 /* The nearest definition is from a lost primary. */
2841 }
2844 /* Find the final overrider. */
2847 {
2850 }
2853 /* Check for adjusting covariant return types. */
2861 /* If the overrider is invalid, don't even try. */
2863 {
2864 /* If FN is a covariant thunk, we must figure out the adjustment
2865 to the final base FN was converting to. As OVERRIDER_TARGET might
2866 also be converting to the return type of FN, we have to
2867 combine the two conversions here. */
2874 {
2878 }
2879 else
2883 /* Find the equivalent binfo within the return type of the
2884 overriding function. We will want the vbase offset from
2885 there. */
2887 over_return);
2890 {
2891 /* There was no existing virtual thunk (which takes
2892 precedence). So find the binfo of the base function's
2893 return type within the overriding function's return type.
2894 Fortunately we know the covariancy is valid (it
2895 has already been checked), so we can just iterate along
2896 the binfos, which have been chained in inheritance graph
2897 order. Of course it is lame that we have to repeat the
2898 search here anyway -- we should really be caching pieces
2899 of the vtable and avoiding this repeated work. */
2903 /* Find the base binfo within the overriding function's
2904 return type. We will always find a thunk_binfo, except
2905 when the covariancy is invalid (which we will have
2906 already diagnosed). */
2915 /* See if virtual inheritance is involved. */
2917 virtual_offset;
2924 {
2928 {
2929 /* We convert via virtual base. Adjust the fixed
2930 offset to be from there. */
2931 offset =
2935 }
2937 /* There was an existing fixed offset, this must be
2938 from the base just converted to, and the base the
2939 FN was thunking to. */
2941 else
2943 }
2944 }
2947 /* Replace the overriding function with a covariant thunk. We
2948 will emit the overriding function in its own slot as
2949 well. */
2952 }
2953 else
2957 /* If we need a covariant thunk, then we may need to adjust first_defn.
2958 The ABI specifies that the thunks emitted with a function are
2959 determined by which bases the function overrides, so we need to be
2960 sure that we're using a thunk for some overridden base; even if we
2961 know that the necessary this adjustment is zero, there may not be an
2962 appropriate zero-this-adjustment thunk for us to use since thunks for
2963 overriding virtual bases always use the vcall offset.
2965 Furthermore, just choosing any base that overrides this function isn't
2966 quite right, as this slot won't be used for calls through a type that
2967 puts a covariant thunk here. Calling the function through such a type
2968 will use a different slot, and that slot is the one that determines
2969 the thunk emitted for that base.
2971 So, keep looking until we find the base that we're really overriding
2972 in this slot: the nearest primary base that doesn't use a covariant
2973 thunk in this slot. */
2975 {
2977 /* We already know that the overrider needs a covariant thunk. */
2980 {
2987 }
2989 }
2991 /* Assume that we will produce a thunk that convert all the way to
2992 the final overrider, and not to an intermediate virtual base. */
2995 /* See if we can convert to an intermediate virtual base first, and then
2996 use the vcall offset located there to finish the conversion. */
2998 {
2999 /* If we find the final overrider, then we can stop
3000 walking. */
3005 /* If we find a virtual base, and we haven't yet found the
3006 overrider, then there is a virtual base between the
3007 declaring base (first_defn) and the final overrider. */
3009 {
3012 }
3013 }
3015 /* Compute the constant adjustment to the `this' pointer. The
3016 `this' pointer, when this function is called, will point at BINFO
3017 (or one of its primary bases, which are at the same offset). */
3019 /* The `this' pointer needs to be adjusted from the declaration to
3020 the nearest virtual base. */
3025 /* If the nearest definition is in a lost primary, we don't need an
3026 entry in our vtable. Except possibly in a constructor vtable,
3027 if we happen to get our primary back. In that case, the offset
3028 will be zero, as it will be a primary base. */
3030 else
3031 /* The `this' pointer needs to be adjusted from pointing to
3032 BINFO to pointing at the base where the final overrider
3033 appears. */
3044 else
3048 }
3050 /* Called from modify_all_vtables via dfs_walk. */
3052 static tree
3054 {
3056 tree virtuals;
3057 tree old_virtuals;
3061 /* A base without a vtable needs no modification, and its bases
3062 are uninteresting. */
3067 /* Don't do the primary vtable, if it's new. */
3071 /* There's no need to modify the vtable for a non-virtual primary
3072 base; we're not going to use that vtable anyhow. We do still
3073 need to do this for virtual primary bases, as they could become
3074 non-primary in a construction vtable. */
3079 /* Now, go through each of the virtual functions in the virtual
3080 function table for BINFO. Find the final overrider, and update
3081 the BINFO_VIRTUALS list appropriately. */
3084 virtuals;
3088 binfo,
3093 }
3095 /* Update all of the primary and secondary vtables for T. Create new
3096 vtables as required, and initialize their RTTI information. Each
3097 of the functions in VIRTUALS is declared in T and may override a
3098 virtual function from a base class; find and modify the appropriate
3099 entries to point to the overriding functions. Returns a list, in
3100 declaration order, of the virtual functions that are declared in T,
3101 but do not appear in the primary base class vtable, and which
3102 should therefore be appended to the end of the vtable for T. */
3104 static tree
3106 {
3110 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
3114 /* Update all of the vtables. */
3117 /* Add virtual functions not already in our primary vtable. These
3118 will be both those introduced by this class, and those overridden
3119 from secondary bases. It does not include virtuals merely
3120 inherited from secondary bases. */
3122 {
3127 {
3128 /* We don't need to adjust the `this' pointer when
3129 calling this function. */
3133 /* This is a function not already in our vtable. Keep it. */
3135 }
3136 else
3137 /* We've already got an entry for this function. Skip it. */
3139 }
3142 }
3144 /* Get the base virtual function declarations in T that have the
3145 indicated NAME. */
3147 static void
3149 {
3152 /* Find virtual functions in T with the indicated NAME. */
3154 {
3156 {
3159 }
3160 }
3167 {
3170 }
3171 }
3173 /* If this method overrides a virtual method from a base, then mark
3174 this member function as being virtual as well. Do 'final' and
3175 'override' checks too. */
3177 void
3179 {
3181 /* In [temp.mem] we have:
3183 A specialization of a member function template does not
3184 override a virtual function from a base class. */
3187 /* IDENTIFIER_VIRTUAL_P indicates whether the name has ever been
3188 used for a vfunc. That avoids the expensive look_for_overrides
3189 call that when we know there's nothing to find. As conversion
3190 operators for the same type can have distinct identifiers, we
3191 cannot optimize those in that way. */
3195 /* Check staticness after we've checked if we 'override'. */
3197 {
3198 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
3199 the error_mark_node so that we know it is an overriding
3200 function. */
3209 }
3214 {
3215 /* Remember this identifier is virtual name. */
3219 /* It's a new vfunc. */
3224 }
3227 }
3229 /* Warn about hidden virtual functions that are not overridden in t.
3230 We know that constructors and destructors don't apply. */
3232 static void
3234 {
3237 {
3245 tree base_binfo;
3246 tree binfo;
3252 /* Iterate through all of the base classes looking for possibly
3253 hidden functions. */
3256 {
3259 }
3261 /* If there are no functions to hide, continue. */
3265 /* Remove any overridden functions. */
3268 {
3272 {
3273 /* If the method from the base class has the same
3274 signature as the method from the derived class, it
3275 has been overridden. Note that we can't move on
3276 after finding one match: fndecl might override
3277 multiple base fns. */
3281 {
3284 }
3285 }
3288 }
3291 /* All the derived fns override base virtuals. */
3294 /* Now give a warning for all base functions without overriders,
3295 as they are hidden. */
3298 {
3299 auto_diagnostic_group d;
3300 /* Here we know it is a hider, and no overrider exists. */
3302 OPT_Woverloaded_virtual_,
3305 }
3306 }
3307 }
3309 /* Recursive helper for finish_struct_anon. */
3311 static void
3313 {
3315 {
3316 /* We're generally only interested in entities the user
3317 declared, but we also find nested classes by noticing
3318 the TYPE_DECL that we create implicitly. You're
3319 allowed to put one anonymous union inside another,
3320 though, so we explicitly tolerate that. We use
3321 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
3322 we also allow unnamed types used for defining fields. */
3331 /* Recurse into the anonymous aggregates to correctly handle
3332 access control (c++/24926):
3334 class A {
3335 union {
3336 union {
3337 int i;
3338 };
3339 };
3340 };
3342 int j=A().i; */
3346 }
3347 }
3349 /* Fix up any anonymous union/struct members of T. */
3351 static void
3353 {
3355 {
3364 }
3365 }
3367 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
3368 will be used later during class template instantiation.
3369 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
3370 a non-static member data (FIELD_DECL), a member function
3371 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
3372 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
3373 When FRIEND_P is nonzero, T is either a friend class
3374 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
3375 (FUNCTION_DECL, TEMPLATE_DECL). */
3377 void
3379 {
3382 {
3387 }
3388 }
3390 /* This function is called from declare_virt_assop_and_dtor via
3391 dfs_walk_all.
3393 DATA is a type that direcly or indirectly inherits the base
3394 represented by BINFO. If BINFO contains a virtual assignment [copy
3395 assignment or move assigment] operator or a virtual constructor,
3396 declare that function in DATA if it hasn't been already declared. */
3398 static tree
3400 {
3408 /* A base without a vtable needs no modification, and its bases
3409 are uninteresting. */
3413 /* If this is a primary base, then we have already looked at the
3414 virtual functions of its vtable. */
3418 {
3422 {
3427 }
3431 }
3434 }
3436 /* If the class type T has a direct or indirect base that contains a
3437 virtual assignment operator or a virtual destructor, declare that
3438 function in T if it hasn't been already declared. */
3440 static void
3442 {
3450 dfs_declare_virt_assop_and_dtor,
3452 }
3454 /* Declare the inheriting constructor for class T inherited from base
3455 constructor CTOR with the parameter array PARMS of size NPARMS. */
3457 static void
3459 {
3462 /* We don't declare an inheriting ctor that would be a default,
3463 copy or move ctor for derived or base. */
3468 {
3472 }
3481 {
3484 }
3485 }
3487 /* Declare all the inheriting constructors for class T inherited from base
3488 constructor CTOR. */
3490 static void
3492 {
3496 {
3501 }
3506 {
3510 }
3513 {
3514 auto_diagnostic_group d;
3518 }
3519 }
3521 /* Implicitly declare T(). */
3523 static void
3525 {
3530 /* Don't force the declaration to get a hard answer; if the
3531 definition would have made the class non-literal, it will still be
3532 non-literal because of the base or member in question, and that
3533 gives a better diagnostic. */
3535 }
3537 /* Create default constructors, assignment operators, and so forth for
3538 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3539 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3540 the class cannot have a default constructor, copy constructor
3541 taking a const reference argument, or an assignment operator taking
3542 a const reference, respectively. */
3544 static void
3548 {
3549 /* Destructor. */
3551 /* In general, we create destructors lazily. */
3560 /* [class.ctor]
3562 If there is no user-declared constructor for a class, a default
3563 constructor is implicitly declared. */
3567 /* [class.ctor]
3569 If a class definition does not explicitly declare a copy
3570 constructor, one is declared implicitly. */
3572 {
3578 }
3580 /* If there is no assignment operator, one will be created if and
3581 when it is needed. For now, just record whether or not the type
3582 of the parameter to the assignment operator will be a const or
3583 non-const reference. */
3585 {
3591 }
3593 /* We can't be lazy about declaring functions that might override
3594 a virtual function from a base class. */
3597 /* If the class definition does not explicitly declare an == operator
3598 function, but declares a defaulted three-way comparison operator function,
3599 an == operator function is declared implicitly. */
3602 {
3604 NULL_TREE);
3609 else
3610 {
3614 }
3616 }
3619 {
3623 {
3624 /* declare, then remove the decl */
3629 {
3631 /* CWG2799: Inheriting a default constructor gives us a default
3632 constructor, not just an inherited constructor. */
3635 }
3638 }
3639 else
3641 }
3642 }
3644 /* Cache of enum_min_precision values. */
3647 /* Return the minimum precision of a bit-field needed to store all
3648 enumerators of ENUMERAL_TYPE TYPE. */
3650 static int
3652 {
3654 /* For unscoped enums without fixed underlying type and without mode
3655 attribute we can just use precision of the underlying type. */
3671 {
3675 {
3686 }
3687 }
3688 else
3696 }
3698 /* FIELD is a bit-field. We are finishing the processing for its
3699 enclosing type. Issue any appropriate messages and set appropriate
3700 flags. Returns false if an error has been diagnosed. */
3702 static bool
3704 {
3706 tree w;
3708 /* Extract the declared width of the bitfield, which has been
3709 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3712 /* Remove the bit-field width indicator so that the rest of the
3713 compiler does not treat that value as a qualifier. */
3716 /* Detect invalid bit-field type. */
3718 {
3722 }
3723 else
3724 {
3726 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3729 /* detect invalid field size. */
3735 {
3738 }
3740 {
3743 }
3745 {
3748 }
3758 {
3764 }
3765 }
3768 {
3772 }
3773 else
3774 {
3775 /* Non-bit-fields are aligned for their type. */
3779 }
3780 }
3782 /* FIELD is a non bit-field. We are finishing the processing for its
3783 enclosing type T. Issue any appropriate messages and set appropriate
3784 flags. */
3786 static bool
3788 tree t,
3791 {
3795 /* In C++98 an anonymous union cannot contain any fields which would change
3796 the settings of CANT_HAVE_CONST_CTOR and friends. */
3798 ;
3799 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3800 structs. So, we recurse through their fields here. */
3802 {
3807 cant_have_const_ctor,
3808 no_const_asn_ref);
3809 }
3810 /* Check members with class type for constructors, destructors,
3811 etc. */
3813 {
3814 /* Never let anything with uninheritable virtuals
3815 make it through without complaint. */
3819 {
3824 field);
3829 field);
3831 {
3835 }
3836 }
3837 else
3838 {
3851 }
3860 }
3865 /* `build_class_init_list' does not recognize
3866 non-FIELD_DECLs. */
3870 }
3872 /* Check the data members (both static and non-static), class-scoped
3873 typedefs, etc., appearing in the declaration of T. Issue
3874 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3875 declaration order) of access declarations; each TREE_VALUE in this
3876 list is a USING_DECL.
3878 In addition, set the following flags:
3880 EMPTY_P
3881 The class is empty, i.e., contains no non-static data members.
3883 CANT_HAVE_CONST_CTOR_P
3884 This class cannot have an implicitly generated copy constructor
3885 taking a const reference.
3887 CANT_HAVE_CONST_ASN_REF
3888 This class cannot have an implicitly generated assignment
3889 operator taking a const reference.
3891 All of these flags should be initialized before calling this
3892 function. */
3894 static void
3898 {
3901 /* Assume there are no access declarations. */
3903 /* Effective C has things to say about classes with pointer members. */
3905 /* Default initialized members affect the whole class. */
3907 /* Lack of any non-static data member of non-volatile literal
3908 type affects a union. */
3910 /* Standard layout requires all FIELDS have same access. */
3914 {
3918 {
3923 /* Save the access declarations for our caller. */
3932 /* FIXME: We should fold in the checking from check_methods. */
3942 {
3943 /* [class.union]
3945 (C++98) If a union contains a static data member,
3946 ... the program is ill-formed. */
3950 }
3955 {
3956 /* [class.union]
3958 If a union contains ... or a [non-static data] member
3959 of reference type, the program is ill-formed. */
3963 }
3965 data_member:
3966 /* Common VAR_DECL & FIELD_DECL processing. */
3970 /* Template instantiation can cause this. Perhaps this
3971 should be a specific instantiation check? */
3973 {
3977 }
3979 {
3983 }
3986 }
3994 /* If it is not a union and at least one non-static data member is
3995 non-literal, the whole class becomes non-literal. Per Core/1453,
3996 volatile non-static data members and base classes are also not allowed.
3997 If it is a union, we might set CLASSTYPE_LITERAL_P after we've seen all
3998 members.
3999 Note: if the type is incomplete we will complain later on. */
4001 {
4004 else
4006 }
4011 {
4012 /* A standard-layout class is a class that:
4014 ... has the same access control (Clause 11) for all
4015 non-static data members, */
4018 else
4021 /* Aggregates must be public. */
4024 }
4026 /* If this is of reference type, check if it needs an init. */
4028 {
4034 {
4035 /* ARM $12.6.2: [A member initializer list] (or, for an
4036 aggregate, initialization by a brace-enclosed list) is the
4037 only way to initialize non-static const and reference
4038 members. */
4041 }
4042 }
4047 {
4049 {
4051 "ignoring packed attribute because of"
4054 }
4058 }
4062 /* We don't treat zero-width bitfields as making a class
4063 non-empty. */
4064 ;
4067 /* Empty data members also don't make a class non-empty. */
4069 else
4070 {
4071 /* The class is non-empty. */
4073 /* The class is not even nearly empty. */
4075 /* If one of the data members contains an empty class, so
4076 does T. */
4080 }
4082 /* This is used by -Weffc++ (see below). Warn only for pointers
4083 to members which might hold dynamic memory. So do not warn
4084 for pointers to functions or pointers to members. */
4090 {
4095 }
4101 {
4108 }
4111 /* DR 148 now allows pointers to members (which are POD themselves),
4112 to be allowed in POD structs. */
4116 /* A potentially-overlapping non-static data member makes the class
4117 non-layout-POD. */
4126 /* We set DECL_C_BIT_FIELD in grokbitfield.
4127 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
4133 {
4136 {
4140 default_init_member);
4141 }
4143 }
4145 /* Now that we've removed bit-field widths from DECL_INITIAL,
4146 anything left in DECL_INITIAL is an NSDMI that makes the class
4147 non-aggregate in C++11, and non-layout-POD always. */
4149 {
4152 else
4154 }
4157 {
4158 /* If any field is const, the structure type is pseudo-const. */
4163 {
4164 /* ARM $12.6.2: [A member initializer list] (or, for an
4165 aggregate, initialization by a brace-enclosed list) is the
4166 only way to initialize non-static const and reference
4167 members. */
4170 }
4171 }
4172 /* A field that is pseudo-const makes the structure likewise. */
4174 {
4179 }
4181 /* Core issue 80: A non-static data member is required to have a
4182 different name from the class iff the class has a
4183 user-declared constructor. */
4188 }
4190 /* Per CWG 2096, a type is a literal type if it is a union, and at least
4191 one of its non-static data members is of non-volatile literal type. */
4195 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
4196 it should also define a copy constructor and an assignment operator to
4197 implement the correct copy semantic (deep vs shallow, etc.). As it is
4198 not feasible to check whether the constructors do allocate dynamic memory
4199 and store it within members, we approximate the warning like this:
4201 -- Warn only if there are members which are pointers
4202 -- Warn only if there is a non-trivial constructor (otherwise,
4203 there cannot be memory allocated).
4204 -- Warn only if there is a non-trivial destructor. We assume that the
4205 user at least implemented the cleanup correctly, and a destructor
4206 is needed to free dynamic memory.
4208 This seems enough for practical purposes. */
4210 && pointer_member
4214 {
4216 {
4218 {
4223 }
4229 }
4230 }
4232 /* Non-static data member initializers make the default constructor
4233 non-trivial. */
4235 {
4238 }
4240 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
4244 /* Check anonymous struct/anonymous union fields. */
4247 /* We've built up the list of access declarations in reverse order.
4248 Fix that now. */
4250 }
4252 /* If TYPE is an empty class type, records its OFFSET in the table of
4253 OFFSETS. */
4255 static int
4257 {
4258 splay_tree_node n;
4263 /* Record the location of this empty object in OFFSETS. */
4271 type,
4275 }
4277 /* Returns nonzero if TYPE is an empty class type and there is
4278 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
4280 static int
4282 {
4283 splay_tree_node n;
4284 tree t;
4289 /* Record the location of this empty object in OFFSETS. */
4299 {
4307 {
4311 }
4312 }
4315 {
4320 }
4323 }
4325 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
4326 F for every subobject, passing it the type, offset, and table of
4327 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
4328 be traversed.
4330 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
4331 than MAX_OFFSET will not be walked.
4333 If F returns a nonzero value, the traversal ceases, and that value
4334 is returned. Otherwise, returns zero. */
4336 static int
4338 subobject_offset_fn f,
4339 tree offset,
4340 splay_tree offsets,
4341 tree max_offset,
4343 {
4347 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
4348 stop. */
4356 {
4359 }
4362 {
4363 tree field;
4364 tree binfo;
4367 /* Avoid recursing into objects that are not interesting. */
4371 /* Record the location of TYPE. */
4376 /* Iterate through the direct base classes of TYPE. */
4380 {
4381 tree binfo_offset;
4386 tree orig_binfo;
4387 /* We cannot rely on BINFO_OFFSET being set for the base
4388 class yet, but the offsets for direct non-virtual
4389 bases can be calculated by going back to the TYPE. */
4392 offset,
4396 f,
4397 binfo_offset,
4398 offsets,
4399 max_offset,
4403 }
4406 {
4410 /* Iterate through the virtual base classes of TYPE. In G++
4411 3.2, we included virtual bases in the direct base class
4412 loop above, which results in incorrect results; the
4413 correct offsets for virtual bases are only known when
4414 working with the most derived type. */
4418 {
4420 f,
4422 offset,
4424 offsets,
4425 max_offset,
4429 }
4430 else
4431 {
4432 /* We still have to walk the primary base, if it is
4433 virtual. (If it is non-virtual, then it was walked
4434 above.) */
4440 {
4441 r = (walk_subobject_offsets
4446 }
4447 }
4448 }
4450 /* Iterate through the fields of TYPE. */
4455 {
4456 tree field_offset;
4461 f,
4463 offset,
4464 field_offset),
4465 offsets,
4466 max_offset,
4470 }
4471 }
4473 {
4476 tree index;
4478 /* Avoid recursing into objects that are not interesting. */
4481 || !domain
4485 /* Step through each of the elements in the array. */
4489 {
4491 f,
4492 offset,
4493 offsets,
4494 max_offset,
4500 /* If this new OFFSET is bigger than the MAX_OFFSET, then
4501 there's no point in iterating through the remaining
4502 elements of the array. */
4505 }
4506 }
4509 }
4511 /* Return true iff FIELD_DECL DECL is potentially overlapping. */
4513 static bool
4515 {
4516 /* Base fields are actually potentially overlapping, but C++ bases go through
4517 a different code path based on binfos, and ObjC++ base fields are laid out
4518 in objc-act, so we don't want layout_class_type to mess with them. */
4520 {
4523 }
4527 }
4529 /* Return true iff DECL is an empty field, either for an empty base or a
4530 [[no_unique_address]] data member. */
4532 bool
4534 {
4542 /* Empty fields should have size zero. */
4546 }
4548 /* Record all of the empty subobjects of DECL_OR_BINFO. */
4550 static void
4552 splay_tree offsets)
4553 {
4558 {
4564 }
4565 else
4566 {
4571 }
4573 tree max_offset;
4574 /* If recording subobjects for a non-static data member or a
4575 non-empty base class, we do not need to record offsets beyond
4576 the size of the biggest empty class. Additional data members
4577 will go at the end of the class. Additional base classes will go
4578 either at offset zero (if empty, in which case they cannot
4579 overlap with offsets past the size of the biggest empty class) or
4580 at the end of the class.
4582 However, if we are placing an empty base class, then we must record
4583 all offsets, as either the empty class is at offset zero (where
4584 other empty classes might later be placed) or at the end of the
4585 class (where other objects might then be placed, so other empty
4586 subobjects might later overlap). */
4590 else
4594 }
4596 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4597 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4598 virtual bases of TYPE are examined. */
4600 static int
4602 tree offset,
4603 splay_tree offsets,
4605 {
4606 splay_tree_node max_node;
4608 /* Get the node in OFFSETS that indicates the maximum offset where
4609 an empty subobject is located. */
4611 /* If there aren't any empty subobjects, then there's no point in
4612 performing this check. */
4618 vbases_p);
4619 }
4621 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4622 non-static data member of the type indicated by RLI. BINFO is the
4623 binfo corresponding to the base subobject, OFFSETS maps offsets to
4624 types already located at those offsets. This function determines
4625 the position of the DECL. */
4627 static void
4629 tree decl,
4630 tree binfo,
4631 splay_tree offsets)
4632 {
4635 tree type;
4638 {
4639 /* For the purposes of determining layout conflicts, we want to
4640 use the class type of BINFO; TREE_TYPE (DECL) will be the
4641 CLASSTYPE_AS_BASE version, which does not contain entries for
4642 zero-sized bases. */
4645 }
4646 else
4647 {
4650 }
4652 /* Try to place the field. It may take more than one try if we have
4653 a hard time placing the field without putting two objects of the
4654 same type at the same address. */
4656 {
4659 /* Place this field. */
4663 /* We have to check to see whether or not there is already
4664 something of the same type at the offset we're about to use.
4665 For example, consider:
4667 struct S {};
4668 struct T : public S { int i; };
4669 struct U : public S, public T {};
4671 Here, we put S at offset zero in U. Then, we can't put T at
4672 offset zero -- its S component would be at the same address
4673 as the S we already allocated. So, we have to skip ahead.
4674 Since all data members, including those whose type is an
4675 empty class, have nonzero size, any overlap can happen only
4676 with a direct or indirect base-class -- it can't happen with
4677 a data member. */
4678 /* In a union, overlap is permitted; all members are placed at
4679 offset zero. */
4684 {
4685 /* Strip off the size allocated to this field. That puts us
4686 at the first place we could have put the field with
4687 proper alignment. */
4690 /* Bump up by the alignment required for the type. */
4691 rli->bitpos
4697 }
4700 {
4701 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4702 the offset wasn't aligned like a pointer when we started to
4703 layout this field, that affects its position. */
4706 {
4709 "alignment of %qD increased in %<-fabi-version=9%> "
4711 else
4714 decl);
4715 }
4717 }
4718 else
4719 /* There was no conflict. We're done laying out this field. */
4721 }
4723 /* Now that we know where it will be placed, update its
4724 BINFO_OFFSET. */
4726 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4727 this point because their BINFO_OFFSET is copied from another
4728 hierarchy. Therefore, we may not need to add the entire
4729 OFFSET. */
4735 }
4737 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4739 static int
4741 tree offset,
4743 {
4745 }
4747 /* Layout the empty base BINFO. EOC indicates the byte currently just
4748 past the end of the class, and should be correctly aligned for a
4749 class of the type indicated by BINFO; OFFSETS gives the offsets of
4750 the empty bases allocated so far. T is the most derived
4751 type. Return nonzero iff we added it at the end. */
4753 static bool
4755 splay_tree offsets)
4756 {
4757 tree alignment;
4761 tree type;
4763 {
4766 }
4767 else
4768 {
4771 }
4773 /* On some platforms (ARM), even empty classes will not be
4774 byte-aligned. */
4779 /* This routine should only be used for empty classes. */
4784 else
4787 /* This is an empty base class. We first try to put it at offset
4788 zero. */
4792 offset,
4793 offsets,
4795 {
4796 /* That didn't work. Now, we move forward from the next
4797 available spot in the class. */
4801 {
4803 offset,
4804 offsets,
4806 /* We finally found a spot where there's no overlap. */
4809 /* There's overlap here, too. Bump along to the next spot. */
4811 }
4812 }
4815 {
4820 }
4822 {
4827 }
4830 /* Adjust BINFO_OFFSET (binfo) to be exactly OFFSET. */
4833 else
4834 {
4838 }
4841 }
4843 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4844 fields at NEXT_FIELD, and return it. */
4846 static tree
4848 {
4849 /* Create the FIELD_DECL. */
4859 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4861 else
4862 {
4865 }
4876 /* Add the new FIELD_DECL to the list of fields for T. */
4882 }
4884 /* Layout the base given by BINFO in the class indicated by RLI.
4885 *BASE_ALIGN is a running maximum of the alignments of
4886 any base class. OFFSETS gives the location of empty base
4887 subobjects. T is the most derived type. Return nonzero if the new
4888 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4889 *NEXT_FIELD, unless BINFO is for an empty base class.
4891 Returns the location at which the next field should be inserted. */
4896 {
4901 /* This error is now reported in xref_tag, thus giving better
4902 location information. */
4905 /* Place the base class. */
4907 {
4908 tree decl;
4910 /* The containing class is non-empty because it has a non-empty
4911 base class. */
4914 /* Create the FIELD_DECL. */
4917 /* Try to place the field. It may take more than one try if we
4918 have a hard time placing the field without putting two
4919 objects of the same type at the same address. */
4921 }
4922 else
4923 {
4925 /* A nearly-empty class "has no proper base class that is empty,
4926 not morally virtual, and at an offset other than zero." */
4928 {
4931 /* The check above (used in G++ 3.2) is insufficient because
4932 an empty class placed at offset zero might itself have an
4933 empty base at a nonzero offset. */
4935 empty_base_at_nonzero_offset_p,
4936 size_zero_node,
4941 }
4943 /* We used to not create a FIELD_DECL for empty base classes because of
4944 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4945 be a problem anymore. We need them to handle initialization of C++17
4946 aggregate bases. */
4948 {
4954 }
4956 /* An empty virtual base causes a class to be non-empty
4957 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4958 here because that was already done when the virtual table
4959 pointer was created. */
4960 }
4962 /* Record the offsets of BINFO and its base subobjects. */
4966 }
4968 /* Layout all of the non-virtual base classes. Record empty
4969 subobjects in OFFSETS. T is the most derived type. Return nonzero
4970 if the type cannot be nearly empty. The fields created
4971 corresponding to the base classes will be inserted at
4972 *NEXT_FIELD. */
4974 static void
4977 {
4978 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4979 subobjects. */
4984 /* The primary base class is always allocated first. */
4987 {
4988 /* We need to walk BINFO_BASE_BINFO to find the access of the primary
4989 base, if it is direct. Indirect base fields are private. */
4992 {
4995 {
4998 }
4999 }
5001 primary_access,
5003 }
5005 /* Now allocate the rest of the bases. */
5007 {
5010 /* The primary base was already allocated above, so we don't
5011 need to allocate it again here. */
5015 /* Virtual bases are added at the end (a primary virtual base
5016 will have already been added). */
5023 }
5024 }
5026 /* Go through the TYPE_FIELDS of T issuing any appropriate
5027 diagnostics, figuring out which methods override which other
5028 methods, and so forth. */
5030 static void
5032 {
5035 {
5041 /* The name of the field is the original field name
5042 Save this in auxiliary field for later overloading. */
5044 {
5048 }
5054 "%<transaction_safe_dynamic%> may only be specified for "
5056 }
5058 /* Check whether the eligible special member functions (P0848) are
5059 user-provided. add_method arranged that the CLASSTYPE_MEMBER_VEC only
5060 has the eligible ones, unless none are eligible; TYPE_FIELDS also contains
5061 ineligible overloads, which is why this needs to be separate from the loop
5062 above. */
5065 {
5067 {
5068 /* P0848: At the end of the definition of a class, overload
5069 resolution is performed among the prospective destructors declared
5070 in that class with an empty argument list to select the destructor
5071 for the class, also known as the selected destructor. The program
5072 is ill-formed if overload resolution fails. */
5079 auto_diagnostic_group d;
5082 else
5086 /* Arbitrarily prune the overload set to a single function for
5087 sake of error recovery. */
5090 }
5093 }
5096 {
5107 }
5110 {
5121 }
5122 }
5124 /* FN is constructor, destructor or operator function. Clone the
5125 declaration to create a NAME'd variant. NEED_VTT_PARM_P and
5126 OMIT_INHERITED_PARMS_P are relevant if it's a cdtor. */
5128 static tree
5131 {
5132 /* Copy the function. */
5134 /* Reset the function name. */
5138 /* Clone constraints. */
5143 /* There's no pending inline data for this function. */
5148 {
5149 /* The base-class destructor is not virtual. */
5152 }
5154 {
5155 /* Set the operator code. */
5159 /* The operator could be virtual. */
5162 }
5167 /* If there was an in-charge parameter, drop it from the function
5168 type. */
5170 {
5173 /* Skip the `this' parameter. */
5175 /* Skip the in-charge parameter. */
5177 /* And the VTT parm, in a complete [cd]tor. */
5181 {
5182 /* If we're omitting inherited parms, that just leaves the VTT. */
5185 }
5189 parmtypes);
5195 }
5197 /* Copy the function parameters. */
5200 /* Remove the in-charge parameter. */
5202 {
5206 }
5208 /* And the VTT parm, in a complete [cd]tor. */
5210 {
5213 else
5214 {
5218 }
5219 }
5221 /* A base constructor inheriting from a virtual base doesn't get the
5222 arguments. */
5227 {
5230 }
5232 /* Create the RTL for this function. */
5235 /* Regardless of the current scope, this is a member function, so
5236 not at namespace scope. */
5240 }
5242 /* FN is an operator function, create a variant for CODE. */
5244 tree
5246 {
5249 }
5251 /* FN is a constructor or destructor. Clone the declaration to create
5252 a specialized in-charge or not-in-charge version, as indicated by
5253 NAME. */
5255 static tree
5258 {
5259 tree clone;
5261 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
5263 {
5275 }
5276 else
5277 {
5283 }
5285 /* Remember where this function came from. */
5288 /* Make it easy to find the CLONE given the FN. Note the
5289 template_result of a template will be chained this way too. */
5294 }
5296 /* Build the clones of FN, return the number of clones built. These
5297 will be inserted onto DECL_CHAIN of FN. */
5299 void
5302 {
5306 {
5307 /* For each constructor, we need two variants: an in-charge version
5308 and a not-in-charge version. */
5311 base_omits_inherited_p);
5313 }
5314 else
5315 {
5318 /* For each destructor, we need three variants: an in-charge
5319 version, a not-in-charge version, and an in-charge deleting
5320 version. We clone the deleting version first because that
5321 means it will go second on the TYPE_FIELDS list -- and that
5322 corresponds to the correct layout order in the virtual
5323 function table.
5325 For a non-virtual destructor, we do not build a deleting
5326 destructor. */
5328 {
5330 count++;
5331 }
5335 }
5337 /* The original is now an abstract function that is never
5338 emitted. */
5343 {
5346 }
5347 }
5349 /* Produce declarations for all appropriate clones of FN. If
5350 UPDATE_METHODS is true, the clones are added to the
5351 CLASSTYPE_MEMBER_VEC. */
5353 void
5355 {
5356 /* Avoid inappropriate cloning. */
5361 /* Base cdtors need a vtt parm if there are virtual bases. */
5364 /* Base ctor omits inherited parms it needs a vttparm and inherited
5365 from a virtual nase ctor. */
5370 }
5372 /* DECL is an in charge constructor, which is being defined. This will
5373 have had an in class declaration, from whence clones were
5374 declared. An out-of-class definition can specify additional default
5375 arguments. As it is the clones that are involved in overload
5376 resolution, we must propagate the information from the DECL to its
5377 clones. */
5379 void
5381 {
5382 tree clone;
5386 {
5391 /* Skip the 'this' parameter. */
5407 {
5409 {
5413 }
5419 {
5420 /* A default parameter has been added. Adjust the
5421 clone's parameters. */
5425 {
5428 clone_parms);
5430 }
5433 tree type
5436 clone_parms);
5444 }
5445 }
5447 }
5448 }
5450 /* For each of the constructors and destructors in T, create an
5451 in-charge and not-in-charge variant. */
5453 static void
5455 {
5456 /* We do not need to propagate the usingness to the clone, at this
5457 point that is not needed. */
5463 }
5465 /* Deduce noexcept for a destructor DTOR. */
5467 void
5469 {
5472 noexcept_deferred_spec);
5473 }
5475 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
5476 of TYPE for virtual functions which FNDECL overrides. Return a
5477 mask of the tm attributes found therein. */
5479 static int
5481 {
5483 tree base_binfo;
5487 {
5495 {
5499 else
5502 }
5503 else
5505 }
5508 }
5510 /* Subroutine of set_method_tm_attributes. Handle the checks and
5511 inheritance for one virtual method FNDECL. */
5513 static void
5515 {
5516 tree tm_attr;
5521 /* If FNDECL doesn't actually override anything (i.e. T is the
5522 class that first declares FNDECL virtual), then we're done. */
5529 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
5530 tm_pure must match exactly, otherwise no weakening of
5531 tm_safe > tm_callable > nothing. */
5532 /* ??? The tm_pure attribute didn't make the transition to the
5533 multivendor language spec. */
5535 {
5537 {
5540 }
5541 }
5542 /* If the overridden function is tm_pure, then FNDECL must be. */
5545 /* Look for base class combinations that cannot be satisfied. */
5547 {
5553 }
5554 /* If FNDECL did not declare an attribute, then inherit the most
5555 restrictive one. */
5557 {
5559 }
5560 /* Otherwise validate that we're not weaker than a function
5561 that is being overridden. */
5562 else
5563 {
5567 }
5570 err_override:
5574 }
5576 /* For each of the methods in T, propagate a class-level tm attribute. */
5578 static void
5580 {
5583 /* Don't bother collecting tm attributes if transactional memory
5584 support is not enabled. */
5588 /* Process virtual methods first, as they inherit directly from the
5589 base virtual function and also require validation of new attributes. */
5591 {
5592 tree vchain;
5595 {
5600 }
5601 }
5603 /* If the class doesn't have an attribute, nothing more to do. */
5608 /* Any method that does not yet have a tm attribute inherits
5609 the one from the class. */
5614 }
5616 /* Returns true if FN is a default constructor. */
5618 bool
5620 {
5623 }
5625 /* Returns true iff class T has a user-provided constructor that can be called
5626 with more than zero arguments. */
5628 bool
5630 {
5635 {
5641 }
5644 }
5646 /* Returns the defaulted constructor if T has one. Otherwise, returns
5647 NULL_TREE. */
5649 tree
5651 {
5656 {
5662 }
5665 }
5667 /* Returns true iff FN is a user-provided function, i.e. user-declared
5668 and not defaulted at its first declaration. */
5670 bool
5672 {
5677 }
5679 /* Returns true iff class T has a user-provided constructor. */
5681 bool
5683 {
5695 }
5697 /* Returns true iff class T has a user-provided or explicit constructor. */
5699 bool
5701 {
5709 {
5713 }
5716 }
5718 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5719 declared or explicitly defaulted in the class body) default
5720 constructor. */
5722 bool
5724 {
5731 {
5737 }
5740 }
5742 /* TYPE is being used as a virtual base, and has a non-trivial move
5743 assignment. Return true if this is due to there being a user-provided
5744 move assignment in TYPE or one of its subobjects; if there isn't, then
5745 multiple move assignment can't cause any harm. */
5747 bool
5749 {
5750 /* Does the type itself have a user-provided move assignment operator? */
5758 /* Do any of its bases? */
5760 tree base_binfo;
5765 /* Or non-static data members? */
5767 {
5772 }
5774 /* Seems not. */
5776 }
5778 /* If default-initialization leaves part of TYPE uninitialized, returns
5779 a DECL for the field or TYPE itself (DR 253). */
5781 tree
5783 {
5794 {
5798 }
5802 {
5806 }
5809 }
5811 /* Returns true iff for class T, a trivial synthesized default constructor
5812 would be constexpr. */
5814 bool
5816 {
5817 /* A defaulted trivial default constructor is constexpr
5818 if there is nothing to initialize. */
5820 /* A class with a vptr doesn't have a trivial default ctor.
5821 In C++20, a class can have transient uninitialized members, e.g.:
5823 struct S { int i; constexpr S() = default; };
5825 should work. */
5828 }
5830 /* Returns true iff class T has a constexpr default constructor. */
5832 bool
5834 {
5835 tree fns;
5838 {
5839 /* The caller should have stripped an enclosing array. */
5842 }
5844 {
5847 /* Non-trivial, we need to check subobject constructors. */
5849 }
5852 }
5854 /* Returns true iff class T has a constexpr default constructor or has an
5855 implicitly declared default constructor that we can't tell if it's constexpr
5856 without forcing a lazy declaration (which might cause undesired
5857 instantiations). */
5859 static bool
5861 {
5864 /* Assume it's constexpr. */
5867 }
5869 /* Returns true iff class T has a constexpr destructor. */
5871 bool
5873 {
5874 tree fns;
5877 /* Non-trivial, we need to check subobject destructors. */
5881 }
5883 /* Returns true iff class T has a constexpr destructor or has an
5884 implicitly declared destructor that we can't tell if it's constexpr
5885 without forcing a lazy declaration (which might cause undesired
5886 instantiations). */
5888 static bool
5890 {
5891 /* Until C++20, only trivial destruction is constexpr. */
5897 /* Assume it's constexpr. */
5901 }
5903 /* Returns true iff class TYPE has a virtual destructor. */
5905 bool
5907 {
5908 tree dtor;
5916 }
5918 /* True iff class TYPE has a non-deleted trivial default
5919 constructor. */
5922 {
5924 }
5926 /* Returns true iff T, a class, has a move-assignment or
5927 move-constructor. Does not lazily declare either.
5928 If USER_P is false, any move function will do. If it is true, the
5929 move function must be user-declared.
5931 Note that user-declared here is different from "user-provided",
5932 which doesn't include functions that are defaulted in the
5933 class. */
5935 bool
5937 {
5957 }
5959 /* True iff T has a move constructor that is not deleted. */
5961 bool
5963 {
5970 }
5972 /* If T, a class, has a user-provided copy constructor, copy assignment
5973 operator, or destructor, returns that function. Otherwise, null. */
5975 tree
5977 {
5980 {
5984 }
5990 {
5995 }
5998 {
6002 }
6005 }
6007 /* True iff T has a member or friend declaration of operator OP. */
6009 bool
6011 {
6019 }
6022 /* If T has a defaulted member or friend declaration of OP, return it. */
6024 tree
6026 {
6029 {
6033 }
6037 {
6041 }
6043 }
6045 /* Nonzero if we need to build up a constructor call when initializing an
6046 object of this class, either because it has a user-declared constructor
6047 or because it doesn't have a default constructor (so we need to give an
6048 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
6049 what you care about is whether or not an object can be produced by a
6050 constructor (e.g. so we don't set TREE_READONLY on const variables of
6051 such type); use this function when what you care about is whether or not
6052 to try to call a constructor to create an object. The latter case is
6053 the former plus some cases of constructors that cannot be called. */
6055 bool
6057 {
6058 tree inner;
6068 /* A user-declared constructor might be private, and a constructor might
6069 be trivial but deleted. */
6072 {
6079 }
6081 }
6083 /* Like type_build_ctor_call, but for destructors. */
6085 bool
6087 {
6088 tree inner;
6097 /* A user-declared destructor might be private, and a destructor might
6098 be trivial but deleted. */
6101 {
6108 }
6110 }
6112 /* Returns TRUE iff we need a cookie when dynamically allocating an
6113 array whose elements have the indicated class TYPE. */
6115 static bool
6117 {
6118 tree fns;
6123 /* If there's a non-trivial destructor, we need a cookie. In order
6124 to iterate through the array calling the destructor for each
6125 element, we'll have to know how many elements there are. */
6129 /* If the usual deallocation function is a two-argument whose second
6130 argument is of type `size_t', then we have to pass the size of
6131 the array to the deallocation function, so we will need to store
6132 a cookie. */
6136 /* If there are no `operator []' members, or the lookup is
6137 ambiguous, then we don't need a cookie. */
6140 /* Loop through all of the functions. */
6142 {
6145 /* See if this function is a one-argument delete function. If
6146 it is, then it will be the usual deallocation function. */
6150 /* Do not consider this function if its second argument is an
6151 ellipsis. */
6154 /* Otherwise, if we have a two-argument function and the second
6155 argument is `size_t', it will be the usual deallocation
6156 function -- unless there is one-argument function, too. */
6160 }
6163 }
6165 /* Finish computing the `literal type' property of class type T.
6167 At this point, we have already processed base classes and
6168 non-static data members. We need to check whether the copy
6169 constructor is trivial, the destructor is trivial, and there
6170 is a trivial default constructor or at least one constexpr
6171 constructor other than the copy constructor. */
6173 static void
6175 {
6176 tree fn;
6190 /* C++14 DR 1684 removed this restriction. */
6198 {
6201 {
6202 auto_diagnostic_group d;
6204 "enclosing class of %<constexpr%> non-static "
6207 }
6208 }
6209 }
6211 /* T is a non-literal type used in a context which requires a constant
6212 expression. Explain why it isn't literal. */
6214 void
6216 {
6226 /* Already explained. */
6229 auto_diagnostic_group d;
6233 " %qT is a closure type, which is only literal in "
6240 t);
6245 {
6247 " %q+T is not an aggregate, does not have a trivial "
6248 "default constructor, and has no %<constexpr%> constructor that "
6251 /* Note that we can't simply call locate_ctor because when the
6252 constructor is deleted it just returns NULL_TREE. */
6254 {
6261 {
6264 else
6267 }
6268 }
6269 }
6270 else
6271 {
6275 {
6278 {
6284 }
6285 }
6287 {
6288 tree ftype;
6293 {
6296 field);
6299 }
6303 }
6304 }
6305 }
6307 /* Check the validity of the bases and members declared in T. Add any
6308 implicitly-generated functions (like copy-constructors and
6309 assignment operators). Compute various flag bits (like
6310 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
6311 level: i.e., independently of the ABI in use. */
6313 static void
6315 {
6316 /* Nonzero if the implicitly generated copy constructor should take
6317 a non-const reference argument. */
6319 /* Nonzero if the implicitly generated assignment operator
6320 should take a non-const reference argument. */
6322 tree access_decls;
6325 tree fn;
6327 /* By default, we use const reference arguments and generate default
6328 constructors. */
6332 /* Check all the base-classes and set FMEM members to point to arrays
6333 of potential interest. */
6336 /* Deduce noexcept on destructor. This needs to happen after we've set
6337 triviality flags appropriately for our bases, and before checking
6338 overriden virtual functions via check_methods. */
6344 /* Check all the method declarations. */
6347 /* Save the initial values of these flags which only indicate whether
6348 or not the class has user-provided functions. As we analyze the
6349 bases and members we can set these flags for other reasons. */
6353 /* Check all the data member declarations. We cannot call
6354 check_field_decls until we have called check_bases check_methods,
6355 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
6356 being set appropriately. */
6361 /* A nearly-empty class has to be vptr-containing; a nearly empty
6362 class contains just a vptr. */
6366 /* Do some bookkeeping that will guide the generation of implicitly
6367 declared member functions. */
6370 /* We need to call a constructor for this class if it has a
6371 user-provided constructor, or if the default constructor is going
6372 to initialize the vptr. (This is not an if-and-only-if;
6373 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
6374 themselves need constructing.) */
6377 /* [dcl.init.aggr]
6379 An aggregate is an array or a class with no user-provided
6380 constructors ... and no virtual functions.
6382 Again, other conditions for being an aggregate are checked
6383 elsewhere. */
6389 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
6390 retain the old definition internally for ABI reasons. */
6399 /* Is this class non-layout-POD because it wasn't an aggregate in C++98? */
6401 {
6403 /* It's non-POD for another reason. */
6407 }
6409 /* If the only explicitly declared default constructor is user-provided,
6410 set TYPE_HAS_COMPLEX_DFLT. */
6416 /* Warn if a public base of a polymorphic type has an accessible
6417 non-virtual destructor. It is only now that we know the class is
6418 polymorphic. Although a polymorphic base will have a already
6419 been diagnosed during its definition, we warn on use too. */
6421 {
6424 tree base_binfo;
6428 {
6436 basetype);
6437 }
6438 }
6440 /* If the class has no user-declared constructor, but does have
6441 non-static const or reference data members that can never be
6442 initialized, issue a warning. */
6444 /* Classes with user-declared constructors are presumed to
6445 initialize these members. */
6447 /* Aggregates can be initialized with brace-enclosed
6448 initializers. */
6450 {
6451 tree field;
6454 {
6455 tree type;
6472 }
6473 }
6475 /* Synthesize any needed methods. */
6477 cant_have_const_ctor,
6478 no_const_asn_ref);
6480 /* Check defaulted declarations here so we have cant_have_const_ctor
6481 and don't need to worry about clones. */
6486 {
6487 /* ...except handle comparisons later, in finish_struct_1. */
6493 {
6494 bool imp_const_p
6500 /* If the function is defaulted outside the class, we just
6501 give the synthesis error. Core Issue #1331 says this is
6502 no longer ill-formed, it is defined as deleted instead. */
6504 }
6506 }
6509 /* "This class type is not an aggregate." */
6512 /* Compute the 'literal type' property before we
6513 do anything with non-static member functions. */
6516 /* Create the in-charge and not-in-charge variants of constructors
6517 and destructors. */
6520 /* Process the using-declarations. */
6524 /* Figure out whether or not we will need a cookie when dynamically
6525 allocating an array of this type. */
6529 /* Classes marked hot or cold propagate the attribute to all members. We
6530 may do this now that methods are declared. This does miss some lazily
6531 declared special member functions (CLASSTYPE_LAZY_*), which are handled
6532 in lazily_declare_fn later on. */
6534 }
6536 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
6537 accordingly. If a new vfield was created (because T doesn't have a
6538 primary base class), then the newly created field is returned. It
6539 is not added to the TYPE_FIELDS list; it is the caller's
6540 responsibility to do that. Accumulate declared virtual functions
6541 on VIRTUALS_P. */
6543 static tree
6545 {
6546 tree fn;
6548 /* Collect the virtual functions declared in T. */
6553 {
6562 }
6564 /* If we couldn't find an appropriate base class, create a new field
6565 here. Even if there weren't any new virtual functions, we might need a
6566 new virtual function table if we're supposed to include vptrs in
6567 all classes that need them. */
6569 {
6570 /* We build this decl with vtbl_ptr_type_node, which is a
6571 `vtable_entry_type*'. It might seem more precise to use
6572 `vtable_entry_type (*)[N]' where N is the number of virtual
6573 functions. However, that would require the vtable pointer in
6574 base classes to have a different type than the vtable pointer
6575 in derived classes. We could make that happen, but that
6576 still wouldn't solve all the problems. In particular, the
6577 type-based alias analysis code would decide that assignments
6578 to the base class vtable pointer can't alias assignments to
6579 the derived class vtable pointer, since they have different
6580 types. Thus, in a derived class destructor, where the base
6581 class constructor was inlined, we could generate bad code for
6582 setting up the vtable pointer.
6584 Therefore, we use one type for all vtable pointers. We still
6585 use a type-correct type; it's just doesn't indicate the array
6586 bounds. That's better than using `void*' or some such; it's
6587 cleaner, and it let's the alias analysis code know that these
6588 stores cannot alias stores to void*! */
6589 tree field;
6602 /* This class is non-empty. */
6606 }
6609 }
6611 /* Add OFFSET to all base types of BINFO which is a base in the
6612 hierarchy dominated by T.
6614 OFFSET, which is a type offset, is number of bytes. */
6616 static void
6618 {
6620 tree primary_binfo;
6621 tree base_binfo;
6623 /* Update BINFO's offset. */
6628 offset));
6630 /* Find the primary base class. */
6636 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
6637 downwards. */
6639 {
6640 /* Don't do the primary base twice. */
6648 }
6649 }
6651 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
6652 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
6653 empty subobjects of T. */
6655 static void
6657 {
6658 tree vbase;
6665 /* Find the last field. The artificial fields created for virtual
6666 bases will go after the last extant field to date. */
6671 /* Go through the virtual bases, allocating space for each virtual
6672 base that is not already a primary base class. These are
6673 allocated in inheritance graph order. */
6675 {
6680 {
6681 /* This virtual base is not a primary base of any class in the
6682 hierarchy, so we have to add space for it. */
6684 access_private_node,
6686 }
6687 }
6688 }
6690 /* Returns the offset of the byte just past the end of the base class
6691 BINFO. */
6693 static tree
6695 {
6696 tree size;
6701 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
6702 allocate some space for it. It cannot have virtual bases, so
6703 TYPE_SIZE_UNIT is fine. */
6705 else
6709 }
6711 /* Returns one of three variations of the ending offset of T. If MODE is
6712 eoc_nvsize, the result is the ABI "nvsize" (i.e. sizeof before allocating
6713 vbases). If MODE is eoc_vsize, the result is the sizeof after allocating
6714 vbases but before rounding, which is not named in the ABI. If MODE is
6715 eoc_nv_or_dsize, the result is the greater of "nvsize" and "dsize" (the size
6716 of the actual data in the class, kinda), as used for allocation of
6717 potentially-overlapping fields. */
6720 static tree
6722 {
6725 tree binfo;
6726 tree base_binfo;
6727 tree offset;
6732 {
6741 }
6746 {
6749 /* DECL_SIZE_UNIT can be null for a flexible array. */
6753 /* For empty fields DECL_SIZE_UNIT is 0, but we want the
6754 size of the type (usually 1) for computing nvsize. */
6758 {
6763 }
6764 else
6768 }
6773 {
6775 /* For dsize, don't count trailing empty bases. */
6778 else
6782 }
6785 }
6787 /* Warn as appropriate about the change in whether we pack into the tail
6788 padding of FIELD, a base field which has a C++14 aggregate type with default
6789 member initializers. */
6791 static void
6793 {
6813 {
6817 "%<-std=c++14%> and up changes in "
6819 else
6821 "%<-std=c++14%> and up changes in "
6823 }
6824 }
6826 /* Warn about bases of T that are inaccessible because they are
6827 ambiguous. For example:
6829 struct S {};
6830 struct T : public S {};
6831 struct U : public S, public T {};
6833 Here, `(S*) new U' is not allowed because there are two `S'
6834 subobjects of U. */
6836 static void
6838 {
6841 tree basetype;
6842 tree binfo;
6843 tree base_binfo;
6845 /* If not checking for warning then return early. */
6849 /* If there are no repeated bases, nothing can be ambiguous. */
6853 /* Check direct bases. */
6856 {
6862 }
6864 /* Check for ambiguous virtual bases. */
6868 {
6874 }
6875 }
6877 /* Compare two INTEGER_CSTs K1 and K2. */
6879 static int
6881 {
6883 }
6885 /* Increase the size indicated in RLI to account for empty classes
6886 that are "off the end" of the class. */
6888 static void
6890 {
6891 tree eoc;
6892 tree rli_size;
6894 /* It might be the case that we grew the class to allocate a
6895 zero-sized base class. That won't be reflected in RLI, yet,
6896 because we are willing to overlay multiple bases at the same
6897 offset. However, now we need to make sure that RLI is big enough
6898 to reflect the entire class. */
6903 {
6904 /* The size should have been rounded to a whole byte. */
6907 rli->bitpos
6916 }
6917 }
6919 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
6920 BINFO_OFFSETs for all of the base-classes. Position the vtable
6921 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
6923 static void
6925 {
6926 tree non_static_data_members;
6927 tree field;
6928 tree vptr;
6929 record_layout_info rli;
6930 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6931 types that appear at that offset. */
6932 splay_tree empty_base_offsets;
6933 /* True if the last field laid out was a bit-field. */
6935 /* The location at which the next field should be inserted. */
6938 /* Keep track of the first non-static data member. */
6941 /* Start laying out the record. */
6944 /* Mark all the primary bases in the hierarchy. */
6947 /* Create a pointer to our virtual function table. */
6950 /* The vptr is always the first thing in the class. */
6952 {
6957 }
6958 else
6961 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6966 /* Layout the non-static data members. */
6968 {
6969 tree type;
6970 tree padding;
6972 /* We still pass things that aren't non-static data members to
6973 the back end, in case it wants to do something with them. */
6975 {
6977 /* If the static data member has incomplete type, keep track
6978 of it so that it can be completed later. (The handling
6979 of pending statics in finish_record_layout is
6980 insufficient; consider:
6982 struct S1;
6983 struct S2 { static S1 s1; };
6985 At this point, finish_record_layout will be called, but
6986 S1 is still incomplete.) */
6988 {
6990 /* The visibility of static data members is determined
6991 at their point of declaration, not their point of
6992 definition. */
6994 }
6996 }
7008 {
7009 /* if D is a potentially-overlapping data member, update sizeof(C) to
7010 max (sizeof(C), offset(D)+max (nvsize(D), dsize(D))). */
7013 else
7014 {
7018 }
7019 }
7021 /* If this field is a bit-field whose width is greater than its
7022 type, then there are some special rules for allocating
7023 it. */
7026 {
7028 /* We must allocate the bits as if suitably aligned for the
7029 longest integer type that fits in this many bits. Then,
7030 we are supposed to use the left over bits as additional
7031 padding. */
7033 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
7041 {
7043 /* Too big, so our current guess is what we want. */
7045 /* Not bigger than limit, ok */
7047 }
7049 /* Figure out how much additional padding is required. */
7051 /* In a union, the padding field must have the full width
7052 of the bit-field; all fields start at offset zero. */
7054 else
7061 /* An unnamed bitfield does not normally affect the
7062 alignment of the containing class on a target where
7063 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
7064 make any exceptions for unnamed bitfields when the
7065 bitfields are longer than their types. Therefore, we
7066 temporarily give the field a name. */
7068 {
7071 }
7077 empty_base_offsets);
7080 /* Now that layout has been performed, set the size of the
7081 field to the size of its declared type; the rest of the
7082 field is effectively invisible. */
7084 /* We must also reset the DECL_MODE of the field. */
7086 }
7088 {
7091 }
7092 else
7094 empty_base_offsets);
7096 /* Remember the location of any empty classes in FIELD. */
7099 /* If a bit-field does not immediately follow another bit-field,
7100 and yet it starts in the middle of a byte, we have failed to
7101 comply with the ABI. */
7104 /* The TREE_NO_WARNING flag gets set by Objective-C when
7105 laying out an Objective-C class. The ObjC ABI differs
7106 from the C++ ABI, and so we do not want a warning
7107 here. */
7109 && !last_field_was_bitfield
7112 bitsize_unit_node)))
7114 "offset of %qD is not ABI-compliant and may "
7117 /* The middle end uses the type of expressions to determine the
7118 possible range of expression values. In order to optimize
7119 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
7120 must be made aware of the width of "i", via its type.
7122 Because C++ does not have integer types of arbitrary width,
7123 we must (for the purposes of the front end) convert from the
7124 type assigned here to the declared type of the bitfield
7125 whenever a bitfield expression is used as an rvalue.
7126 Similarly, when assigning a value to a bitfield, the value
7127 must be converted to the type given the bitfield here. */
7129 {
7134 {
7141 }
7142 }
7144 /* If we needed additional padding after this field, add it
7145 now. */
7147 {
7148 tree padding_field;
7151 FIELD_DECL,
7152 NULL_TREE,
7153 char_type_node);
7161 NULL_TREE,
7162 empty_base_offsets);
7163 }
7166 }
7169 {
7170 /* Make sure that we are on a byte boundary so that the size of
7171 the class without virtual bases will always be a round number
7172 of bytes. */
7175 }
7177 /* We used to remove zero width bitfields at this point since PR42217,
7178 while the C FE never did that. That caused ABI differences on various
7179 targets. Set the DECL_FIELD_CXX_ZERO_WIDTH_BIT_FIELD flag on them
7180 instead, so that the backends can emit -Wpsabi warnings in the cases
7181 where the ABI changed. */
7183 {
7186 /* We should not be confused by the fact that grokbitfield
7187 temporarily sets the width of the bit field into
7188 DECL_BIT_FIELD_REPRESENTATIVE (field).
7189 check_bitfield_decl eventually sets DECL_SIZE (field)
7190 to that width. */
7196 }
7199 {
7200 /* T needs a different layout as a base (eliding virtual bases
7201 or whatever). Create that version. */
7210 /* If the ABI version is not at least two, and the last
7211 field was a bit-field, RLI may not be on a byte
7212 boundary. In particular, rli_size_unit_so_far might
7213 indicate the last complete byte, while rli_size_so_far
7214 indicates the total number of bits used. Therefore,
7215 rli_size_so_far, rather than rli_size_unit_so_far, is
7216 used to compute TYPE_SIZE_UNIT. */
7218 /* Set the size and alignment for the new type. */
7226 eoc);
7238 /* Copy the non-static data members of T. This will include its
7239 direct non-virtual bases & vtable. */
7243 {
7245 /* Zap any NSDMI, it's not needed and might be a deferred
7246 parse. */
7250 }
7253 /* We use the base type for trivial assignments, and hence it
7254 needs a mode. */
7257 /* Record the base version of the type. */
7259 }
7260 else
7263 /* Every empty class contains an empty class. */
7267 /* Set the TYPE_DECL for this type to contain the right
7268 value for DECL_OFFSET, so that we can use it as part
7269 of a COMPONENT_REF for multiple inheritance. */
7272 /* Now fix up any virtual base class types that we left lying
7273 around. We must get these done before we try to lay out the
7274 virtual function table. As a side-effect, this will remove the
7275 base subobject fields. */
7278 /* Make sure that empty classes are reflected in RLI at this
7279 point. */
7282 /* Make sure not to create any structures with zero size. */
7288 /* If this is a non-POD, declaring it packed makes a difference to how it
7289 can be used as a field; don't let finalize_record_size undo it. */
7293 /* Let the back end lay out the type. */
7296 /* If we didn't end up needing an as-base type, don't use it. */
7298 /* If T's CLASSTYPE_AS_BASE is TYPE_USER_ALIGN, but T is not,
7299 replacing the as-base type would change CLASSTYPE_USER_ALIGN,
7300 causing us to lose the user-specified alignment as in PR94050. */
7312 /* Warn about bases that can't be talked about due to ambiguity. */
7315 /* Now that we're done with layout, give the base fields the real types. */
7320 /* Clean up. */
7327 }
7329 /* Determine the "key method" for the class type indicated by TYPE,
7330 and set CLASSTYPE_KEY_METHOD accordingly. */
7332 void
7334 {
7335 tree method;
7342 /* The key method is the first non-pure virtual function that is not
7343 inline at the point of class definition. On some targets the
7344 key function may not be inline; those targets should not call
7345 this function until the end of the translation unit. */
7351 {
7354 }
7357 }
7359 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
7360 class data member of non-zero size, otherwise false. */
7364 {
7372 {
7376 }
7379 }
7381 /* Used by find_flexarrays and related functions. */
7383 struct flexmems_t
7384 {
7385 /* The first flexible array member or non-zero array member found
7386 in the order of layout. */
7387 tree array;
7388 /* First non-static non-empty data member in the class or its bases. */
7389 tree first;
7390 /* The first non-static non-empty data member following either
7391 the flexible array member, if found, or the zero-length array member
7392 otherwise. AFTER[1] refers to the first such data member of a union
7393 of which the struct containing the flexible array member or zero-length
7394 array is a member, or NULL when no such union exists. This element is
7395 only used during searching, not for diagnosing problems. AFTER[0]
7396 refers to the first such data member that is not a member of such
7397 a union. */
7400 /* Refers to a struct (not union) in which the struct of which the flexible
7401 array is member is defined. Used to diagnose strictly (according to C)
7402 invalid uses of the latter structs. */
7403 tree enclosing;
7404 };
7406 /* Find either the first flexible array member or the first zero-length
7407 array, in that order of preference, among members of class T (but not
7408 its base classes), and set members of FMEM accordingly.
7409 BASE_P is true if T is a base class of another class.
7410 PUN is set to the outermost union in which the flexible array member
7411 (or zero-length array) is defined if one such union exists, otherwise
7412 to NULL.
7413 Similarly, PSTR is set to a data member of the outermost struct of
7414 which the flexible array is a member if one such struct exists,
7415 otherwise to NULL. */
7417 static void
7421 {
7422 /* Set the "pointer" to the outermost enclosing union if not set
7423 yet and maintain it for the remainder of the recursion. */
7428 {
7432 /* Is FLD a typedef for an anonymous struct? */
7434 /* FIXME: Note that typedefs (as well as arrays) need to be fully
7435 handled elsewhere so that errors like the following are detected
7436 as well:
7437 typedef struct { int i, a[], j; } S; // bug c++/72753
7438 S s [2]; // bug c++/68489
7439 */
7444 {
7445 /* Check the nested unnamed type referenced via a typedef
7446 independently of FMEM (since it's not a data member of
7447 the enclosing class). */
7450 }
7452 /* Skip anything that's GCC-generated or not a (non-static) data
7453 member. */
7457 /* Type of the member. */
7462 /* Determine the type of the array element or object referenced
7463 by the member so that it can be checked for flexible array
7464 members if it hasn't been yet. */
7471 {
7473 {
7474 /* Once the member after the flexible array has been found
7475 we're done. */
7478 }
7481 {
7482 /* Descend into the non-static member struct or union and try
7483 to find a flexible array member or zero-length array among
7484 its members. This is only necessary for anonymous types
7485 and types in whose context the current type T has not been
7486 defined (the latter must not be checked again because they
7487 are already in the process of being checked by one of the
7488 recursive calls). */
7493 /* If this member isn't anonymous and a prior non-flexible array
7494 member has been seen in one of the enclosing structs, clear
7495 the FIRST member since it doesn't contribute to the flexible
7496 array struct's members. */
7507 {
7508 /* Restore the FIRST member reset above if no flexible
7509 array member has been found in this member's struct. */
7511 }
7513 /* If the member struct contains the first flexible array
7514 member, or if this member is a base class, continue to
7515 the next member and avoid setting the FMEM->NEXT pointer
7516 to point to it. */
7519 }
7520 }
7523 {
7524 /* Remember the first non-static data member. */
7528 /* Remember the first non-static data member after the flexible
7529 array member, if one has been found, or the zero-length array
7530 if it has been found. */
7533 }
7535 /* Skip non-arrays. */
7539 /* Determine the upper bound of the array if it has one. */
7541 {
7543 {
7544 /* Make a record of the zero-length array if either one
7545 such field or a flexible array member has been seen to
7546 handle the pathological and unlikely case of multiple
7547 such members. */
7550 }
7552 {
7553 /* Remember the first zero-length array unless a flexible array
7554 member has already been seen. */
7557 }
7558 }
7559 else
7560 {
7561 /* Flexible array members have no upper bound. */
7563 {
7565 {
7566 /* Replace the zero-length array if it's been stored and
7567 reset the after pointer. */
7571 }
7573 /* Make a record of another flexible array member. */
7575 }
7576 else
7577 {
7580 }
7581 }
7582 }
7583 }
7585 /* Diagnose a strictly (by the C standard) invalid use of a struct with
7586 a flexible array member (or the zero-length array extension). */
7588 static void
7590 {
7592 {
7593 auto_diagnostic_group d;
7604 }
7605 }
7607 /* Issue diagnostics for invalid flexible array members or zero-length
7608 arrays that are not the last elements of the containing class or its
7609 base classes or that are its sole members. */
7611 static void
7613 {
7618 {
7621 }
7623 /* Has a diagnostic been issued? */
7629 {
7636 {
7639 auto_diagnostic_group d;
7641 {
7644 }
7645 }
7646 }
7647 else
7648 {
7655 {
7659 auto_diagnostic_group d;
7662 /* In the unlikely event that the member following the flexible
7663 array member is declared in a different class, or the member
7664 overlaps another member of a common union, point to it.
7665 Otherwise it should be obvious. */
7669 {
7674 }
7675 }
7676 }
7680 }
7683 /* Recursively check to make sure that any flexible array or zero-length
7684 array members of class T or its bases are valid (i.e., not the sole
7685 non-static data member of T and, if one exists, that it is the last
7686 non-static data member of T and its base classes. FMEM is expected
7687 to be initially null and is used internally by recursive calls to
7688 the function. Issue the appropriate diagnostics for the array member
7689 that fails the checks. */
7691 static void
7694 {
7695 /* Initialize the result of a search for flexible array and zero-length
7696 array members. Avoid doing any work if the most interesting FMEM data
7697 have already been populated. */
7706 /* Recursively check the primary base class first. */
7708 {
7711 }
7713 /* Recursively check the base classes. */
7716 {
7719 /* The primary base class was already checked above. */
7723 /* Virtual base classes are at the end. */
7727 /* Check the base class. */
7729 }
7732 {
7733 /* Check virtual base classes only once per derived class.
7734 I.e., this check is not performed recursively for base
7735 classes. */
7737 tree base_binfo;
7741 {
7742 /* Check the virtual base class. */
7746 }
7747 }
7749 /* Is the type unnamed (and therefore a member of it potentially
7750 an anonymous struct or union)? */
7755 /* Search the members of the current (possibly derived) class, skipping
7756 unnamed structs and unions since those could be anonymous. */
7761 {
7762 /* Issue diagnostics for invalid flexible and zero-length array
7763 members found in base classes or among the members of the current
7764 class. Ignore anonymous structs and unions whose members are
7765 considered to be members of the enclosing class and thus will
7766 be diagnosed when checking it. */
7768 }
7769 }
7771 /* Perform processing required when the definition of T (a class type)
7772 is complete. Diagnose invalid definitions of flexible array members
7773 and zero-size arrays. */
7775 void
7777 {
7778 tree x;
7779 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
7783 {
7788 }
7790 /* If this type was previously laid out as a forward reference,
7791 make sure we lay it out again. */
7795 /* Make assumptions about the class; we'll reset the flags if
7796 necessary. */
7802 /* Do end-of-class semantic processing: checking the validity of the
7803 bases and members and add implicitly generated methods. */
7806 /* Find the key method. */
7808 {
7809 /* The Itanium C++ ABI permits the key method to be chosen when
7810 the class is defined -- even though the key method so
7811 selected may later turn out to be an inline function. On
7812 some systems (such as ARM Symbian OS) the key method cannot
7813 be determined until the end of the translation unit. On such
7814 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
7815 will cause the class to be added to KEYED_CLASSES. Then, in
7816 finish_file we will determine the key method. */
7820 /* If a polymorphic class has no key method, we may emit the vtable
7821 in every translation unit where the class definition appears. If
7822 we're devirtualizing, we can look into the vtable even if we
7823 aren't emitting it. */
7826 }
7828 /* Layout the class itself. */
7830 /* COMPLETE_TYPE_P is now true. */
7834 /* With the layout complete, check for flexible array members and
7835 zero-length arrays that might overlap other members in the final
7836 layout. */
7841 /* If necessary, create the primary vtable for this class. */
7843 {
7844 /* We must enter these virtuals into the table. */
7848 /* Here we know enough to change the type of our virtual
7849 function table, but we will wait until later this function. */
7852 /* If we're warning about ABI tags, check the types of the new
7853 virtual functions. */
7857 }
7860 {
7862 tree fn;
7869 /* Add entries for virtual functions introduced by this class. */
7873 /* Set DECL_VINDEX for all functions declared in this class. */
7875 fn;
7877 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
7879 {
7883 /* A thunk. We should never be calling this entry directly
7884 from this vtable -- we'd use the entry for the non
7885 thunk base function. */
7889 }
7890 }
7898 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
7899 for any static member objects of the type we're working on. */
7902 {
7903 /* Synthesize constexpr defaulted comparisons. */
7909 }
7915 /* Complain if one of the field types requires lower visibility. */
7918 /* Make the rtl for any new vtables we have created, and unmark
7919 the base types we marked. */
7922 /* Build the VTT for T. */
7929 "%q#T has virtual functions and accessible"
7937 /* Class layout, assignment of virtual table slots, etc., is now
7938 complete. Give the back end a chance to tweak the visibility of
7939 the class or perform any other required target modifications. */
7949 /* Finish debugging output for this type. */
7953 {
7956 {
7959 }
7961 {
7964 else
7965 {
7968 }
7970 }
7972 {
7974 "the type of the first field has a different ABI from the "
7977 }
7978 }
7979 }
7981 /* When T was built up, the member declarations were added in reverse
7982 order. Rearrange them to declaration order. */
7984 void
7986 {
7987 tree next;
7988 tree prev;
7989 tree x;
7991 /* The following lists are all in reverse order. Put them in
7992 declaration order now. */
7995 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
7996 order, so we can't just use nreverse. Due to stat_hack
7997 chicanery in finish_member_declaration. */
8002 {
8006 }
8009 {
8012 }
8013 }
8015 /* Classes, structs or unions T marked with hotness attributes propagate
8016 the attribute to all methods. */
8018 void
8020 {
8026 tree class_has_cold_attr
8028 tree class_has_hot_attr
8035 }
8037 tree
8039 {
8042 /* Now that we've got all the field declarations, reverse everything
8043 as necessary. */
8049 /* Nadger the current location so that diagnostics point to the start of
8050 the struct, not the end. */
8054 {
8055 tree x;
8059 {
8063 }
8065 {
8068 }
8070 /* Also add a USING_DECL for operator=. We know there'll be (at
8071 least) one, but we don't know the signature(s). We want name
8072 lookup not to fail or recurse into bases. This isn't added
8073 to the template decl list so we drop this at instantiation
8074 time. */
8076 NULL_TREE);
8086 /* COMPLETE_TYPE_P is now true. */
8090 /* We need to emit an error message if this type was used as a parameter
8091 and it is an abstract type, even if it is a template. We construct
8092 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
8093 account and we call complete_vars with this type, which will check
8094 the PARM_DECLS. Note that while the type is being defined,
8095 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
8096 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
8103 /* Remember current #pragma pack value. */
8107 {
8111 }
8115 /* Fix up any variants we've already built. */
8117 }
8118 else
8120 /* COMPLETE_TYPE_P is now true. */
8125 {
8126 /* People keep complaining that the compiler crashes on an invalid
8127 definition of initializer_list, so I guess we should explicitly
8128 reject it. What the compiler internals care about is that it's a
8129 template and has a pointer field followed by size_type field. */
8132 {
8135 {
8139 }
8140 }
8141 /* It also cannot be a union. */
8146 }
8154 else
8166 /* Lambdas are defined by the LAMBDA_EXPR. */
8171 }
8172 \f
8173 /* Hash table to avoid endless recursion when handling references. */
8176 /* Return the dynamic type of INSTANCE, if known.
8177 Used to determine whether the virtual function table is needed
8178 or not.
8180 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
8181 of our knowledge of its type. *NONNULL should be initialized
8182 before this function is called. */
8184 static tree
8186 {
8187 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
8190 {
8194 else
8198 /* This is a call to a constructor, hence it's never zero. */
8201 {
8205 }
8209 /* This is a call to a constructor, hence it's never zero. */
8211 {
8215 }
8224 /* Propagate nonnull. */
8229 CASE_CONVERT:
8235 {
8236 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
8237 with a real object -- given &p->f, p can still be null. */
8239 /* ??? Probably should check DECL_WEAK here. */
8242 }
8246 /* If this component is really a base class reference, then the field
8247 itself isn't definitive. */
8256 {
8260 }
8261 /* fall through. */
8266 {
8270 }
8272 {
8276 /* if we're in a ctor or dtor, we know our type. If
8277 current_class_ptr is set but we aren't in a function, we're in
8278 an NSDMI (and therefore a constructor). */
8283 {
8287 }
8288 }
8290 {
8291 /* We only need one hash table because it is always left empty. */
8293 fixed_type_or_null_ref_ht
8296 /* Reference variables should be references to objects. */
8300 /* Enter the INSTANCE in a table to prevent recursion; a
8301 variable's initializer may refer to the variable
8302 itself. */
8307 {
8308 tree type;
8317 }
8318 }
8324 else
8325 /* TODO: Recursion may be correct for some non-location-wrapper
8326 uses of VIEW_CONVERT_EXPR. */
8331 }
8332 #undef RECUR
8333 }
8335 /* Return nonzero if the dynamic type of INSTANCE is known, and
8336 equivalent to the static type. We also handle the case where
8337 INSTANCE is really a pointer. Return negative if this is a
8338 ctor/dtor. There the dynamic type is known, but this might not be
8339 the most derived base of the original object, and hence virtual
8340 bases may not be laid out according to this type.
8342 Used to determine whether the virtual function table is needed
8343 or not.
8345 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
8346 of our knowledge of its type. *NONNULL should be initialized
8347 before this function is called. */
8349 int
8351 {
8354 tree fixed;
8356 /* processing_template_decl can be false in a template if we're in
8357 instantiate_non_dependent_expr, but we still want to suppress
8358 this check. */
8360 {
8361 /* In a template we only care about the type of the result. */
8365 }
8377 }
8379 \f
8380 void
8382 {
8385 current_class_stack
8392 }
8394 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
8396 static void
8398 {
8399 tree type;
8401 /* We are re-entering the same class we just left, so we don't
8402 have to search the whole inheritance matrix to find all the
8403 decls to bind again. Instead, we install the cached
8404 class_shadowed list and walk through it binding names. */
8407 /* Restore IDENTIFIER_TYPE_VALUE. */
8409 type;
8412 }
8414 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
8415 appropriate for TYPE.
8417 So that we may avoid calls to lookup_name, we cache the _TYPE
8418 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
8420 For multiple inheritance, we perform a two-pass depth-first search
8421 of the type lattice. */
8423 void
8425 {
8426 class_stack_node_t csn;
8430 /* Make sure there is enough room for the new entry on the stack. */
8432 {
8434 current_class_stack
8436 current_class_stack_size);
8437 }
8439 /* Insert a new entry on the class stack. */
8446 current_class_depth++;
8448 /* Now set up the new type. */
8454 /* By default, things in classes are private, while things in
8455 structures or unions are public. */
8457 ? access_private_node
8463 {
8464 /* Forcibly remove any old class remnants. */
8466 }
8472 else
8474 }
8476 /* Get out of the current class scope. If we were in a class scope
8477 previously, that is the one popped to. */
8479 void
8481 {
8484 current_class_depth--;
8490 }
8492 /* Mark the top of the class stack as hidden. */
8494 void
8496 {
8499 }
8501 /* Mark the top of the class stack as un-hidden. */
8503 void
8505 {
8508 }
8510 /* If the class type currently being defined is either T or
8511 a nested type of T, returns the type from the current_class_stack,
8512 which might be equivalent to but not equal to T in case of
8513 constrained partial specializations. */
8515 tree
8517 {
8525 /* We start looking from 1 because entry 0 is from global scope,
8526 and has no type. */
8528 {
8529 tree c;
8532 else
8533 {
8537 }
8542 }
8544 }
8546 /* If either current_class_type or one of its enclosing classes are derived
8547 from T, return the appropriate type. Used to determine how we found
8548 something via unqualified lookup. */
8550 tree
8552 {
8555 /* The bases of a dependent type are unknown. */
8566 {
8571 }
8574 }
8576 /* Return the outermost enclosing class type that is still open, or
8577 NULL_TREE. */
8579 tree
8581 {
8588 {
8595 }
8597 }
8599 /* Returns the innermost class type which is not a lambda closure type. */
8601 tree
8603 {
8608 }
8610 /* When entering a class scope, all enclosing class scopes' names with
8611 static meaning (static variables, static functions, types and
8612 enumerators) have to be visible. This recursive function calls
8613 pushclass for all enclosing class contexts until global or a local
8614 scope is reached. TYPE is the enclosed class. */
8616 void
8618 {
8619 /* A namespace might be passed in error cases, like A::B:C. */
8627 }
8629 /* Undoes a push_nested_class call. */
8631 void
8633 {
8639 }
8641 /* Returns the number of extern "LANG" blocks we are nested within. */
8643 int
8645 {
8647 }
8649 /* Set global variables CURRENT_LANG_NAME to appropriate value
8650 so that behavior of name-mangling machinery is correct. */
8652 void
8654 {
8661 else
8663 }
8665 /* Get out of the current language scope. */
8667 void
8669 {
8671 }
8672 \f
8673 /* Type instantiation routines. */
8675 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
8676 matches the TARGET_TYPE. If there is no satisfactory match, return
8677 error_mark_node, and issue an error & warning messages under
8678 control of FLAGS. Permit pointers to member function if FLAGS
8679 permits. If TEMPLATE_ONLY, the name of the overloaded function was
8680 a template-id, and EXPLICIT_TARGS are the explicitly provided
8681 template arguments.
8683 If OVERLOAD is for one or more member functions, then ACCESS_PATH
8684 is the base path used to reference those member functions. If
8685 the address is resolved to a member function, access checks will be
8686 performed and errors issued if appropriate. */
8688 static tree
8690 tree overload,
8691 tsubst_flags_t complain,
8693 tree explicit_targs,
8694 tree access_path)
8695 {
8696 /* Here's what the standard says:
8698 [over.over]
8700 If the name is a function template, template argument deduction
8701 is done, and if the argument deduction succeeds, the deduced
8702 arguments are used to generate a single template function, which
8703 is added to the set of overloaded functions considered.
8705 Non-member functions and static member functions match targets of
8706 type "pointer-to-function" or "reference-to-function." Nonstatic
8707 member functions match targets of type "pointer-to-member
8708 function;" the function type of the pointer to member is used to
8709 select the member function from the set of overloaded member
8710 functions. If a non-static member function is selected, the
8711 reference to the overloaded function name is required to have the
8712 form of a pointer to member as described in 5.3.1.
8714 If more than one function is selected, any template functions in
8715 the set are eliminated if the set also contains a non-template
8716 function, and any given template function is eliminated if the
8717 set contains a second template function that is more specialized
8718 than the first according to the partial ordering rules 14.5.5.2.
8719 After such eliminations, if any, there shall remain exactly one
8720 selected function. */
8723 /* We store the matches in a TREE_LIST rooted here. The functions
8724 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
8725 interoperability with most_specialized_instantiation. */
8727 tree fn;
8728 tree target_fn_type;
8730 /* By the time we get here, we should be seeing only real
8731 pointer-to-member types, not the internal POINTER_TYPE to
8732 METHOD_TYPE representation. */
8738 /* Check that the TARGET_TYPE is reasonable. */
8743 /* This is OK, too. */
8746 /* This is OK, too. This comes from a conversion to reference
8747 type. */
8749 else
8750 {
8756 }
8758 /* Non-member functions and static member functions match targets of type
8759 "pointer-to-function" or "reference-to-function." Nonstatic member
8760 functions match targets of type "pointer-to-member-function;" the
8761 function type of the pointer to member is used to select the member
8762 function from the set of overloaded member functions.
8764 So figure out the FUNCTION_TYPE that we want to match against. */
8767 /* If we can find a non-template function that matches, we can just
8768 use it. There's no point in generating template instantiations
8769 if we're just going to throw them out anyhow. But, of course, we
8770 can only do this when we don't *need* a template function. */
8773 {
8777 /* We're not looking for templates just yet. */
8781 /* We're looking for a non-static member, and this isn't
8782 one, or vice versa. */
8785 /* Constraints must be satisfied. This is done before
8786 return type deduction since that instantiates the
8787 function. */
8792 {
8793 /* Force instantiation to do return type deduction. */
8796 }
8798 /* In C++17 we need the noexcept-qualifier to compare types. */
8803 /* See if there's a match. */
8808 }
8810 /* Now, if we've already got a match (or matches), there's no need
8811 to proceed to the template functions. But, if we don't have a
8812 match we need to look at them, too. */
8814 {
8815 tree target_arg_types;
8816 tree target_ret_type;
8819 tree arg;
8833 {
8835 tree instantiation;
8836 tree targs;
8839 /* We're only looking for templates. */
8844 /* We're not looking for a non-static member, and this is
8845 one, or vice versa. */
8850 /* If the template has a deduced return type, don't expose it to
8851 template argument deduction. */
8855 /* Try to do argument deduction. */
8862 /* Instantiation failed. */
8865 /* Constraints must be satisfied. This is done before
8866 return type deduction since that instantiates the
8867 function. */
8871 /* And now force instantiation to do return type deduction. */
8873 {
8879 }
8881 /* In C++17 we need the noexcept-qualifier to compare types. */
8885 /* See if there's a match. */
8890 }
8892 /* Now, remove all but the most specialized of the matches. */
8894 {
8899 NULL_TREE,
8900 NULL_TREE);
8901 }
8902 }
8904 /* Now we should have exactly one function in MATCHES. */
8906 {
8907 /* There were *no* matches. */
8909 {
8914 }
8916 }
8918 {
8919 /* There were too many matches. First check if they're all
8920 the same function. */
8925 /* For multi-versioned functions, more than one match is just fine and
8926 decls_match will return false as they are different. */
8934 {
8936 {
8940 /* Since print_candidates expects the functions in the
8941 TREE_VALUE slot, we flip them here. */
8946 }
8949 }
8950 }
8952 /* Good, exactly one match. Now, convert it to the correct type. */
8957 {
8958 /* Previously we allowed this behavior for iobj member functions when the
8959 -fms-extensions flag is passed as MSVC allows this as a language
8960 extension. MSVC also allows this for xobj member functions, but the
8961 documentation for -fms-extensions states it's purpose is to support
8962 the use of microsoft headers. Until otherwise demonstrated, we should
8963 assume xobj member functions are not used in this manner in microsoft
8964 headers and forbid the incorrect syntax instead of supporting it for
8965 non-legacy uses. This should hopefully encourage conformance going
8966 forward.
8967 This comment is referred to in typeck.cc:cp_build_addr_expr_1. */
8973 {
8974 auto_diagnostic_group d;
8975 /* Should match the error in typeck.cc:cp_build_addr_expr_1.
8976 We seem to lack the details here to match that diagnostic exactly,
8977 perhaps this could be fixed in the future? See PR113075 bug 2. */
8979 "ISO C++ forbids taking the address of an unqualified"
8980 " or parenthesized non-static member function to form"
8982 /* This is incorrect, see PR113075 bug 3. */
8984 "a pointer to explicit object member function can only be "
8986 }
8987 else
8988 {
8991 /* Is there a reason this error message doesn't match the one in
8992 typeck.cc:cp_build_addr_expr_1? */
8993 auto_diagnostic_group d;
8996 {
9000 }
9001 }
9002 }
9004 /* If a pointer to a function that is multi-versioned is requested, the
9005 pointer to the dispatcher function is returned instead. This works
9006 well because indirectly calling the function will dispatch the right
9007 function version at run-time. */
9009 {
9013 /* Mark all the versions corresponding to the dispatcher as used. */
9016 }
9018 /* If we're doing overload resolution purely for the purpose of
9019 determining conversion sequences, we should not consider the
9020 function used. If this conversion sequence is selected, the
9021 function will be marked as used at this point. */
9023 {
9024 /* Make =delete work with SFINAE. */
9029 }
9031 /* We could not check access to member functions when this
9032 expression was originally created since we did not know at that
9033 time to which function the expression referred. */
9035 {
9038 }
9042 else
9043 {
9044 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
9045 will mark the function as addressed, but here we must do it
9046 explicitly. */
9050 }
9051 }
9053 /* This function will instantiate the type of the expression given in
9054 RHS to match the type of LHSTYPE. If errors exist, then return
9055 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
9056 we complain on errors. If we are not complaining, never modify rhs,
9057 as overload resolution wants to try many possible instantiations, in
9058 the hope that at least one will work.
9060 For non-recursive calls, LHSTYPE should be a function, pointer to
9061 function, or a pointer to member function. */
9063 tree
9065 {
9074 {
9078 }
9081 {
9090 /* Microsoft allows `A::f' to be resolved to a
9091 pointer-to-member. */
9092 ;
9093 else
9094 {
9099 }
9100 }
9102 /* If we instantiate a template, and it is a A ?: C expression
9103 with omitted B, look through the SAVE_EXPR. */
9108 {
9111 }
9113 /* There are only a few kinds of expressions that may have a type
9114 dependent on overload resolution. */
9120 /* This should really only be used when attempting to distinguish
9121 what sort of a pointer to function we have. For now, any
9122 arithmetic operation which is not supported on pointers
9123 is rejected as an error. */
9126 {
9128 {
9134 /* Do not lose object's side effects. */
9138 }
9145 /* This can happen if we are forming a pointer-to-member for a
9146 member template. */
9149 /* Fall through. */
9152 {
9156 return
9160 }
9164 return
9168 access_path);
9171 {
9176 }
9183 }
9185 }
9186 \f
9187 /* Return the name of the virtual function pointer field
9188 (as an IDENTIFIER_NODE) for the given TYPE. Note that
9189 this may have to look back through base types to find the
9190 ultimate field name. (For single inheritance, these could
9191 all be the same name. Who knows for multiple inheritance). */
9193 static tree
9195 {
9201 {
9207 }
9215 }
9217 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
9218 according to [class]:
9219 The class-name is also inserted
9220 into the scope of the class itself. For purposes of access checking,
9221 the inserted class name is treated as if it were a public member name. */
9223 void
9225 {
9243 }
9245 /* Returns 1 if TYPE contains only padding bytes. */
9247 int
9249 {
9257 }
9259 /* Returns true if TYPE contains no actual data, just various
9260 possible combinations of empty classes. If IGNORE_VPTR is true,
9261 a vptr doesn't prevent the class from being considered empty. Typically
9262 we want to ignore the vptr on assignment, and not on initialization. */
9264 bool
9266 {
9268 {
9269 tree field;
9270 tree binfo;
9271 tree base_binfo;
9274 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
9275 out, but we'd like to be able to check this before then. */
9289 /* An unnamed bit-field is not a data member. */
9294 }
9299 }
9301 /* Note that NAME was looked up while the current class was being
9302 defined and that the result of that lookup was DECL. */
9304 void
9306 {
9307 /* If we're not defining a class, there's nothing to do. */
9318 /* Record the binding in the names_used tables for classes inside blev. */
9320 {
9322 ? current_class_type
9326 {
9328 /* We found the declaration. */
9331 /* This class is inside the declaration scope. */
9333 }
9345 }
9346 }
9348 /* Note that NAME was declared (as DECL) in the current class. Check
9349 to see that the declaration is valid under [class.member.lookup]:
9351 If [the result of a search in T for N at point P] differs from the result of
9352 a search in T for N from immediately after the class-specifier of T, the
9353 program is ill-formed, no diagnostic required. */
9355 void
9357 {
9358 splay_tree names_used;
9359 splay_tree_node n;
9361 /* Look to see if we ever used this name. */
9362 names_used
9366 /* The C language allows members to be declared with a type of the same
9367 name, and the C++ standard says this diagnostic is not required. So
9368 allow it in extern "C" blocks unless pedantic is specified.
9369 Allow it in all cases if -ms-extensions is specified. */
9375 {
9379 /* [basic.scope.class]
9381 A name N used in a class S shall refer to the same declaration
9382 in its context and when re-evaluated in the completed scope of
9383 S. */
9391 else
9392 /* Make it an error. */
9397 {
9400 }
9401 }
9402 }
9404 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
9405 Secondary vtables are merged with primary vtables; this function
9406 will return the VAR_DECL for the primary vtable. */
9408 tree
9410 {
9411 tree decl;
9415 {
9418 }
9422 }
9425 /* Returns the binfo for the primary base of BINFO. If the resulting
9426 BINFO is a virtual base, and it is inherited elsewhere in the
9427 hierarchy, then the returned binfo might not be the primary base of
9428 BINFO in the complete object. Check BINFO_PRIMARY_P or
9429 BINFO_LOST_PRIMARY_P to be sure. */
9431 static tree
9433 {
9434 tree primary_base;
9441 }
9443 /* As above, but iterate until we reach the binfo that actually provides the
9444 vptr for BINFO. */
9446 static tree
9448 {
9452 {
9457 }
9459 }
9461 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
9462 type. Note that the virtual inheritance might be above or below BINFO in
9463 the hierarchy. */
9465 bool
9467 {
9471 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
9472 a morally virtual base. */
9475 }
9477 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
9479 static int
9481 {
9485 }
9487 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
9488 INDENT should be zero when called from the top level; it is
9489 incremented recursively. IGO indicates the next expected BINFO in
9490 inheritance graph ordering. */
9492 static tree
9494 dump_flags_t flags,
9495 tree binfo,
9496 tree igo,
9498 {
9500 tree base_binfo;
9507 {
9510 }
9524 {
9528 TFF_PLAIN_IDENTIFIER),
9530 }
9532 {
9535 }
9540 {
9544 {
9548 TFF_PLAIN_IDENTIFIER));
9549 }
9551 {
9555 TFF_PLAIN_IDENTIFIER));
9556 }
9558 {
9562 TFF_PLAIN_IDENTIFIER));
9563 }
9565 {
9569 TFF_PLAIN_IDENTIFIER));
9570 }
9574 }
9580 }
9582 /* Dump the BINFO hierarchy for T. */
9584 static void
9586 {
9598 }
9600 /* Debug interface to hierarchy dumping. */
9602 void
9604 {
9606 }
9608 static void
9610 {
9611 dump_flags_t flags;
9613 {
9616 }
9617 }
9619 static void
9621 {
9622 tree value;
9624 HOST_WIDE_INT elt;
9632 TFF_PLAIN_IDENTIFIER));
9639 }
9641 static void
9643 {
9644 dump_flags_t flags;
9651 {
9658 {
9663 }
9667 }
9670 }
9672 static void
9674 {
9675 dump_flags_t flags;
9682 {
9687 }
9690 }
9692 /* Dump a function or thunk and its thunkees. */
9694 static void
9696 {
9699 tree thunks;
9707 {
9717 else
9723 }
9727 }
9729 /* Dump the thunks for FN. */
9731 void
9733 {
9735 }
9737 /* Virtual function table initialization. */
9739 /* Create all the necessary vtables for T and its base classes. */
9741 static void
9743 {
9744 tree vbase;
9748 /* We lay out the primary and secondary vtables in one contiguous
9749 vtable. The primary vtable is first, followed by the non-virtual
9750 secondary vtables in inheritance graph order. */
9754 /* Then come the virtual bases, also in inheritance graph order. */
9756 {
9760 }
9764 }
9766 /* Initialize the vtable for BINFO with the INITS. */
9768 static void
9770 {
9771 tree decl;
9777 }
9779 /* Build the VTT (virtual table table) for T.
9780 A class requires a VTT if it has virtual bases.
9782 This holds
9783 1 - primary virtual pointer for complete object T
9784 2 - secondary VTTs for each direct non-virtual base of T which requires a
9785 VTT
9786 3 - secondary virtual pointers for each direct or indirect base of T which
9787 has virtual bases or is reachable via a virtual path from T.
9788 4 - secondary VTTs for each direct or indirect virtual base of T.
9790 Secondary VTTs look like complete object VTTs without part 4. */
9792 static void
9794 {
9795 tree type;
9796 tree vtt;
9797 tree index;
9800 /* Build up the initializers for the VTT. */
9805 /* If we didn't need a VTT, we're done. */
9809 /* Figure out the type of the VTT. */
9813 /* Now, build the VTT object itself. */
9816 /* Add the VTT to the vtables list. */
9821 }
9823 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
9824 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
9825 and CHAIN the vtable pointer for this binfo after construction is
9826 complete. VALUE can also be another BINFO, in which case we recurse. */
9828 static tree
9830 {
9831 tree vt;
9834 {
9840 else
9842 }
9845 }
9847 /* Data for secondary VTT initialization. */
9848 struct secondary_vptr_vtt_init_data
9849 {
9850 /* Is this the primary VTT? */
9853 /* Current index into the VTT. */
9854 tree index;
9856 /* Vector of initializers built up. */
9859 /* The type being constructed by this secondary VTT. */
9860 tree type_being_constructed;
9861 };
9863 /* Recursively build the VTT-initializer for BINFO (which is in the
9864 hierarchy dominated by T). INITS points to the end of the initializer
9865 list to date. INDEX is the VTT index where the next element will be
9866 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
9867 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
9868 for virtual bases of T. When it is not so, we build the constructor
9869 vtables for the BINFO-in-T variant. */
9871 static void
9874 {
9876 tree b;
9877 tree init;
9878 secondary_vptr_vtt_init_data data;
9881 /* We only need VTTs for subobjects with virtual bases. */
9885 /* We need to use a construction vtable if this is not the primary
9886 VTT. */
9888 {
9891 /* Record the offset in the VTT where this sub-VTT can be found. */
9893 }
9895 /* Add the address of the primary vtable for the complete object. */
9899 {
9902 }
9905 /* Recursively add the secondary VTTs for non-virtual bases. */
9910 /* Add secondary virtual pointers for all subobjects of BINFO with
9911 either virtual bases or reachable along a virtual path, except
9912 subobjects that are non-virtual primary bases. */
9922 /* data.inits might have grown as we added secondary virtual pointers.
9923 Make sure our caller knows about the new vector. */
9927 /* Add the secondary VTTs for virtual bases in inheritance graph
9928 order. */
9930 {
9935 }
9936 else
9937 /* Remove the ctor vtables we created. */
9939 }
9941 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
9942 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
9944 static tree
9946 {
9949 /* We don't care about bases that don't have vtables. */
9953 /* We're only interested in proper subobjects of the type being
9954 constructed. */
9958 /* We're only interested in bases with virtual bases or reachable
9959 via a virtual path from the type being constructed. */
9964 /* We're not interested in non-virtual primary bases. */
9968 /* Record the index where this secondary vptr can be found. */
9970 {
9975 {
9976 /* It's a primary virtual base, and this is not a
9977 construction vtable. Find the base this is primary of in
9978 the inheritance graph, and use that base's vtable
9979 now. */
9982 }
9983 }
9985 /* Add the initializer for the secondary vptr itself. */
9988 /* Advance the vtt index. */
9993 }
9995 /* Called from build_vtt_inits via dfs_walk. After building
9996 constructor vtables and generating the sub-vtt from them, we need
9997 to restore the BINFO_VTABLES that were scribbled on. DATA is the
9998 binfo of the base whose sub vtt was generated. */
10000 static tree
10002 {
10006 /* If this class has no vtable, none of its bases do. */
10010 /* This might be a primary base, so have no vtable in this
10011 hierarchy. */
10014 /* If we scribbled the construction vtable vptr into BINFO, clear it
10015 out now. */
10021 }
10023 /* Build the construction vtable group for BINFO which is in the
10024 hierarchy dominated by T. */
10026 static void
10028 {
10029 tree type;
10030 tree vtbl;
10031 tree id;
10032 tree vbase;
10035 /* See if we've already created this construction vtable group. */
10041 /* Build a version of VTBL (with the wrong type) for use in
10042 constructing the addresses of secondary vtables in the
10043 construction vtable group. */
10046 /* Don't export construction vtables from shared libraries. Even on
10047 targets that don't support hidden visibility, this tells
10048 can_refer_decl_in_current_unit_p not to assume that it's safe to
10049 access from a different compilation unit (bz 54314). */
10057 /* Add the vtables for each of our virtual bases using the vbase in T
10058 binfo. */
10060 vbase;
10062 {
10063 tree b;
10070 }
10072 /* Figure out the type of the construction vtable. */
10079 /* Initialize the construction vtable. */
10083 }
10085 /* Add the vtbl initializers for BINFO (and its bases other than
10086 non-virtual primaries) to the list of INITS. BINFO is in the
10087 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
10088 the constructor the vtbl inits should be accumulated for. (If this
10089 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
10090 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
10091 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
10092 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
10093 but are not necessarily the same in terms of layout. */
10095 static void
10097 tree orig_binfo,
10098 tree rtti_binfo,
10099 tree vtbl,
10100 tree t,
10102 {
10104 tree base_binfo;
10109 /* If it doesn't have a vptr, we don't do anything. */
10113 /* If we're building a construction vtable, we're not interested in
10114 subobjects that don't require construction vtables. */
10120 /* Build the initializers for the BINFO-in-T vtable. */
10123 /* Walk the BINFO and its bases. We walk in preorder so that as we
10124 initialize each vtable we can figure out at what offset the
10125 secondary vtable lies from the primary vtable. We can't use
10126 dfs_walk here because we need to iterate through bases of BINFO
10127 and RTTI_BINFO simultaneously. */
10129 {
10130 /* Skip virtual bases. */
10136 inits);
10137 }
10138 }
10140 /* Called from accumulate_vtbl_inits. Adds the initializers for the
10141 BINFO vtable to L. */
10143 static void
10145 tree orig_binfo,
10146 tree rtti_binfo,
10147 tree orig_vtbl,
10148 tree t,
10150 {
10157 {
10158 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
10159 primary virtual base. If it is not the same primary in
10160 the hierarchy of T, we'll need to generate a ctor vtable
10161 for it, to place at its location in T. If it is the same
10162 primary, we still need a VTT entry for the vtable, but it
10163 should point to the ctor vtable for the base it is a
10164 primary for within the sub-hierarchy of RTTI_BINFO.
10166 There are three possible cases:
10168 1) We are in the same place.
10169 2) We are a primary base within a lost primary virtual base of
10170 RTTI_BINFO.
10171 3) We are primary to something not a base of RTTI_BINFO. */
10173 tree b;
10176 /* First, look through the bases we are primary to for RTTI_BINFO
10177 or a virtual base. */
10180 {
10185 }
10186 /* If we run out of primary links, keep looking down our
10187 inheritance chain; we might be an indirect primary. */
10191 found:
10193 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
10194 base B and it is a base of RTTI_BINFO, this is case 2. In
10195 either case, we share our vtable with LAST, i.e. the
10196 derived-most base within B of which we are a primary. */
10199 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
10200 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
10201 binfo_ctor_vtable after everything's been set up. */
10204 /* Otherwise, this is case 3 and we get our own. */
10205 }
10212 {
10213 tree index;
10216 /* Add the initializer for this vtable. */
10220 /* Figure out the position to which the VPTR should point. */
10226 }
10229 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
10230 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
10231 straighten this out. */
10234 /* Throw away any unneeded intializers. */
10236 else
10237 /* For an ordinary vtable, set BINFO_VTABLE. */
10239 }
10244 /* Construct the initializer for BINFO's virtual function table. BINFO
10245 is part of the hierarchy dominated by T. If we're building a
10246 construction vtable, the ORIG_BINFO is the binfo we should use to
10247 find the actual function pointers to put in the vtable - but they
10248 can be overridden on the path to most-derived in the graph that
10249 ORIG_BINFO belongs. Otherwise,
10250 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
10251 BINFO that should be indicated by the RTTI information in the
10252 vtable; it will be a base class of T, rather than T itself, if we
10253 are building a construction vtable.
10255 The value returned is a TREE_LIST suitable for wrapping in a
10256 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
10257 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
10258 number of non-function entries in the vtable.
10260 It might seem that this function should never be called with a
10261 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
10262 base is always subsumed by a derived class vtable. However, when
10263 we are building construction vtables, we do build vtables for
10264 primary bases; we need these while the primary base is being
10265 constructed. */
10267 static void
10269 tree orig_binfo,
10270 tree t,
10271 tree rtti_binfo,
10274 {
10275 tree v;
10276 vtbl_init_data vid;
10278 tree vbinfo;
10282 /* Initialize VID. */
10290 /* The first vbase or vcall offset is at index -3 in the vtable. */
10293 /* Add entries to the vtable for RTTI. */
10296 /* Create an array for keeping track of the functions we've
10297 processed. When we see multiple functions with the same
10298 signature, we share the vcall offsets. */
10300 /* Add the vcall and vbase offset entries. */
10303 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
10304 build_vbase_offset_vtbl_entries. */
10309 /* If the target requires padding between data entries, add that now. */
10311 {
10317 /* Move data entries into their new positions and add padding
10318 after the new positions. Iterate backwards so we don't
10319 overwrite entries that we would need to process later. */
10322 ix--)
10323 {
10331 {
10335 null_pointer_node);
10336 }
10337 }
10338 }
10343 /* The initializers for virtual functions were built up in reverse
10344 order. Straighten them out and add them to the running list in one
10345 step. */
10354 /* Go through all the ordinary virtual functions, building up
10355 initializers. */
10357 {
10358 tree delta;
10359 tree vcall_index;
10366 {
10370 {
10373 }
10375 }
10377 /* If the only definition of this function signature along our
10378 primary base chain is from a lost primary, this vtable slot will
10379 never be used, so just zero it out. This is important to avoid
10380 requiring extra thunks which cannot be generated with the function.
10382 We first check this in update_vtable_entry_for_fn, so we handle
10383 restored primary bases properly; we also need to do it here so we
10384 zero out unused slots in ctor vtables, rather than filling them
10385 with erroneous values (though harmless, apart from relocation
10386 costs). */
10391 {
10392 /* Pull the offset for `this', and the function to call, out of
10393 the list. */
10400 /* You can't call an abstract virtual function; it's abstract.
10401 So, we replace these functions with __pure_virtual. */
10403 {
10406 {
10408 abort_fndecl_addr
10412 }
10413 }
10414 /* Likewise for deleted virtuals. */
10416 {
10418 {
10422 dvirt_fn = push_library_fn
10426 }
10431 }
10432 else
10433 {
10435 {
10440 }
10441 /* Take the address of the function, considering it to be of an
10442 appropriate generic type. */
10446 /* Don't refer to a virtual destructor from a constructor
10447 vtable or a vtable for an abstract class, since destroying
10448 an object under construction is undefined behavior and we
10449 don't want it to be considered a candidate for speculative
10450 devirtualization. But do create the thunk for ABI
10451 compliance. */
10456 }
10457 }
10459 /* And add it to the chain of initializers. */
10461 {
10466 else
10468 {
10474 }
10475 }
10476 else
10478 }
10479 }
10481 /* Adds to vid->inits the initializers for the vbase and vcall
10482 offsets in BINFO, which is in the hierarchy dominated by T. */
10484 static void
10486 {
10487 tree b;
10489 /* If this is a derived class, we must first create entries
10490 corresponding to the primary base class. */
10495 /* Add the vbase entries for this base. */
10497 /* Add the vcall entries for this base. */
10499 }
10501 /* Returns the initializers for the vbase offset entries in the vtable
10502 for BINFO (which is part of the class hierarchy dominated by T), in
10503 reverse order. VBASE_OFFSET_INDEX gives the vtable index
10504 where the next vbase offset will go. */
10506 static void
10508 {
10509 tree vbase;
10510 tree t;
10511 tree non_primary_binfo;
10513 /* If there are no virtual baseclasses, then there is nothing to
10514 do. */
10520 /* We might be a primary base class. Go up the inheritance hierarchy
10521 until we find the most derived class of which we are a primary base:
10522 it is the offset of that which we need to use. */
10525 {
10526 tree b;
10528 /* If we have reached a virtual base, then it must be a primary
10529 base (possibly multi-level) of vid->binfo, or we wouldn't
10530 have called build_vcall_and_vbase_vtbl_entries for it. But it
10531 might be a lost primary, so just skip down to vid->binfo. */
10533 {
10536 }
10542 }
10544 /* Go through the virtual bases, adding the offsets. */
10546 vbase;
10548 {
10549 tree b;
10550 tree delta;
10555 /* Find the instance of this virtual base in the complete
10556 object. */
10559 /* If we've already got an offset for this virtual base, we
10560 don't need another one. */
10565 /* Figure out where we can find this vbase offset. */
10574 /* The vbase offset had better be the same. */
10577 /* The next vbase will come at a more negative offset. */
10581 /* The initializer is the delta from BINFO to this virtual base.
10582 The vbase offsets go in reverse inheritance-graph order, and
10583 we are walking in inheritance graph order so these end up in
10584 the right order. */
10591 }
10592 }
10594 /* Adds the initializers for the vcall offset entries in the vtable
10595 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
10596 to VID->INITS. */
10598 static void
10600 {
10601 /* We only need these entries if this base is a virtual base. We
10602 compute the indices -- but do not add to the vtable -- when
10603 building the main vtable for a class. */
10606 /* If BINFO is RTTI_BINFO, then (since BINFO does not
10607 correspond to VID->DERIVED), we are building a primary
10608 construction virtual table. Since this is a primary
10609 virtual table, we do not need the vcall offsets for
10610 BINFO. */
10612 {
10613 /* We need a vcall offset for each of the virtual functions in this
10614 vtable. For example:
10616 class A { virtual void f (); };
10617 class B1 : virtual public A { virtual void f (); };
10618 class B2 : virtual public A { virtual void f (); };
10619 class C: public B1, public B2 { virtual void f (); };
10621 A C object has a primary base of B1, which has a primary base of A. A
10622 C also has a secondary base of B2, which no longer has a primary base
10623 of A. So the B2-in-C construction vtable needs a secondary vtable for
10624 A, which will adjust the A* to a B2* to call f. We have no way of
10625 knowing what (or even whether) this offset will be when we define B2,
10626 so we store this "vcall offset" in the A sub-vtable and look it up in
10627 a "virtual thunk" for B2::f.
10629 We need entries for all the functions in our primary vtable and
10630 in our non-virtual bases' secondary vtables. */
10632 /* If we are just computing the vcall indices -- but do not need
10633 the actual entries -- not that. */
10636 /* Now, walk through the non-virtual bases, adding vcall offsets. */
10638 }
10639 }
10641 /* Build vcall offsets, starting with those for BINFO. */
10643 static void
10645 {
10647 tree primary_binfo;
10648 tree base_binfo;
10650 /* Don't walk into virtual bases -- except, of course, for the
10651 virtual base for which we are building vcall offsets. Any
10652 primary virtual base will have already had its offsets generated
10653 through the recursion in build_vcall_and_vbase_vtbl_entries. */
10657 /* If BINFO has a primary base, process it first. */
10662 /* Add BINFO itself to the list. */
10665 /* Scan the non-primary bases of BINFO. */
10669 }
10671 /* Called from build_vcall_offset_vtbl_entries_r. */
10673 static void
10675 {
10676 /* Make entries for the rest of the virtuals. */
10677 tree orig_fn;
10679 /* The ABI requires that the methods be processed in declaration
10680 order. */
10682 orig_fn;
10686 }
10688 /* Add a vcall offset entry for ORIG_FN to the vtable. */
10690 static void
10692 {
10694 tree vcall_offset;
10695 tree derived_entry;
10697 /* If there is already an entry for a function with the same
10698 signature as FN, then we do not need a second vcall offset.
10699 Check the list of functions already present in the derived
10700 class vtable. */
10702 {
10704 /* We only use one vcall offset for virtual destructors,
10705 even though there are two virtual table entries. */
10709 }
10711 /* If we are building these vcall offsets as part of building
10712 the vtable for the most derived class, remember the vcall
10713 offset. */
10715 {
10718 }
10720 /* The next vcall offset will be found at a more negative
10721 offset. */
10725 /* Keep track of this function. */
10729 {
10730 tree base;
10731 tree fn;
10733 /* Find the overriding function. */
10737 else
10738 {
10741 /* The vbase we're working on is a primary base of
10742 vid->binfo. But it might be a lost primary, so its
10743 BINFO_OFFSET might be wrong, so we just use the
10744 BINFO_OFFSET from vid->binfo. */
10750 vcall_offset);
10751 }
10752 /* Add the initializer to the vtable. */
10754 }
10755 }
10757 /* Return vtbl initializers for the RTTI entries corresponding to the
10758 BINFO's vtable. The RTTI entries should indicate the object given
10759 by VID->rtti_binfo. */
10761 static void
10763 {
10764 tree b;
10765 tree t;
10766 tree offset;
10767 tree decl;
10768 tree init;
10772 /* To find the complete object, we will first convert to our most
10773 primary base, and then add the offset in the vtbl to that value. */
10778 /* The second entry is the address of the typeinfo object. */
10781 else
10784 /* Convert the declaration to a type that can be stored in the
10785 vtable. */
10789 /* Add the offset-to-top entry. It comes earlier in the vtable than
10790 the typeinfo entry. Convert the offset to look like a
10791 function pointer, so that we can put it in the vtable. */
10794 }
10796 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
10797 accessibility. */
10799 bool
10801 {
10804 }
10806 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
10808 bool
10810 {
10814 }
10816 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
10817 class between them, if any. */
10819 tree
10821 {
10833 {
10836 }
10840 }