| blob | f3cfa9f0f23acb875654039e038d795ae55685ba |
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 parameters of an xobj and iobj member function
1023 correspond. This function assumes that the iobj parameter has been correctly
1024 adjusted when the function is introduced by a using declaration per
1025 [over.match.funcs.general.4]. */
1027 bool
1029 {
1037 /* A reference, pointer, or something else. */
1042 /* Will work for a pointer or reference param type. So this will continue
1043 to work even if we change how the object parameter of an iobj member
1044 function is represented. */
1045 tree iobj_param_type
1048 /* If the iobj member function was introduced with a using declaration, the
1049 type of its object parameter is considered to be that of the class it was
1050 introduced into.
1052 [over.match.funcs.general.4]
1053 For non-conversion functions that are implicit object member
1054 functions nominated by a using-declaration in a derived class, the
1055 function is considered to be a member of the derived class for the purpose
1056 of defining the type of the implicit object parameter.
1058 Unfortunately, because of this rule, we can't just compare the xobj member
1059 function's DECL_CONTEXT to its object parameter.
1061 struct S;
1063 struct B {
1064 int f(this S&) { return 5; }
1065 };
1067 struct S : B {
1068 using B::f;
1069 int f() { return 10; }
1070 };
1072 The using declaration does not change the object parameter of B::f as it
1073 is an xobj member function. However, its object parameter still
1074 corresponds to S::f as it was declared with an object parameter of type
1075 S const&. The DECL_CONTEXT of B::f is B, so if we compare the type of the
1076 object parameter to that, it will not match. If we naively assume a
1077 different type from the DECL_CONTEXT for an xobj parameter means that the
1078 object parameters do not correspond, then the object parameters in the
1079 above example will be considered non-corresponding.
1081 As a result of this, B::f would incorrectly not be discarded, causing an
1082 ambiguity when f is called on an object of type S.
1084 This also impacts member functions with constraints as in the following
1085 example.
1087 template<typename = void>
1088 struct S;
1090 template<typename = void>
1091 struct B {
1092 int f(this S<>&) requires true { return 5; }
1093 };
1095 template<typename>
1096 struct S : B<> {
1097 using B<>::f;
1098 int f() { return 10; }
1099 };
1101 Once again, if we compare the DECL_CONTEXT of B<>::f to it's xobj
1102 parameter, it would not match. If the object parameters do not
1103 correspond, constraints are not taken into account, so in this example we
1104 would (probably) get an ambiguous lookup instead of correctly picking
1105 B<>::f.
1107 Because of this caveat, we must actually compare the type of the iobj
1108 parameter to the type of the xobj parameter, shortcuts will have these
1109 edge cases.
1111 Aside from the more complex reasons above, this logic also implicitly
1112 handles xobj parameters of pointer type, we don't have to explicitly
1113 check for that case. */
1115 /* FIXME:
1117 template<typename>
1118 struct S;
1120 template<typename>
1121 struct B {
1122 int f(this S<void>&) requires true { return 5; }
1123 };
1125 template<typename>
1126 struct S : B<void> {
1127 using B<void>::f;
1128 int f() { return 10; }
1129 };
1131 This case is broken, the incomplete type seems to screw with things.
1132 I'm not sure how to fix that so I'm just noting the issue here, I have a
1133 feeling it's trivial to do if you know how. */
1138 /* We don't get to bail yet even if we have a by-value xobj parameter,
1139 a by-value xobj parameter can correspond to an iobj parameter provided the
1140 iobj member function is not declared with a reference qualifier.
1142 From this point on, we know we are dealing with an xobj parameter that has
1143 an object parameter of the same type as the class it was declared in.
1144 We still don't know if we have a reference or by-value parameter yet
1145 though. */
1148 /* We only care about cv qualifiers when determining correspondence. */
1152 /* We need to ignore the ref qualifier of the xobj parameter if the iobj
1153 member function lacks a ref qualifier.
1155 [basic.scope.scope.3]
1156 Two non-static member functions have corresponding object parameters if:
1157 -- exactly one is an implicit object member function with no ref-qualifier
1158 and the types of their object parameters ([dcl.fct]), after removing
1159 top-level references, are the same, or
1160 -- their object parameters have the same type.
1162 The cv qualifiers of a by-value parameter are supposed to be discarded, so
1163 we ignore them.
1165 [dcl.fct.5]
1166 After producing the list of parameter types, any top-level cv-qualifiers
1167 modifying a parameter type are deleted when forming the function type.
1169 However, they still need to be taken into account when our xobj parameter
1170 is a reference that is being ignored (according to [basic.scope.scope.3]
1171 quoted above), but when we are actually dealing with a by-value xobj
1172 parameter we can proceed following this table.
1173 | iobj | xobj | equal |
1174 | none | none | X |
1175 | none | c | X |
1176 | none | v | X |
1177 | none | cv | X |
1178 | c | none | O |
1179 | c | c | O |
1180 | c | v | O |
1181 | c | cv | O |
1182 | v | none | O |
1183 | v | c | O |
1184 | v | v | O |
1185 | v | cv | O |
1186 | cv | none | O |
1187 | cv | c | O |
1188 | cv | v | O |
1189 | cv | cv | O |
1191 Additionally, if the iobj member function is ref qualified, we aren't
1192 ignoring the ref qualifier of the iobj parameter, so we can't be dealing
1193 with correspondence in that case either.
1195 So to recap, if we have a by-value xobj parameter, we know for sure that
1196 we aren't dealing with corresponding object parameters if the iobj member
1197 function has any cv-ref qualifiers. The only case where we might still be
1198 dealing with corresponding object parameters is when the iobj member
1199 function lacks any cv-ref qualification. */
1201 {
1204 }
1205 else
1206 {
1207 /* We are dealing with an xobj parameter that is a reference now, but due
1208 to [basic.scope.scope.3] we need to ignore its ref qual. */
1216 /* Even if we are ignoring the reference qualifier, the xobj parameter
1217 was still a reference so we still take the cv qualifiers into
1218 account. */
1219 cp_cv_quals const xobj_cv_quals
1222 /* Finally, if the qualifications don't match exactly, the object
1223 parameters don't correspond. */
1227 }
1228 /* If we got past everything else, the object parameters of fn1 and fn2
1229 definitely correspond. */
1231 }
1233 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
1234 METHOD is being injected via a using_decl. Returns true if the
1235 method could be added to the method vec. */
1237 bool
1239 {
1248 /* See below. */
1251 /* Check to see if we've already got this method. */
1253 {
1259 /* Two using-declarations can coexist, we'll complain about ambiguity in
1260 overload resolution. */
1262 /* Except handle inherited constructors specially. */
1264 {
1266 /* Don't add the same one twice. */
1269 }
1271 /* [over.load] Member function declarations with the
1272 same name and the same parameter types cannot be
1273 overloaded if any of them is a static member
1274 function declaration.
1276 [over.load] Member function declarations with the same name and
1277 the same parameter-type-list as well as member function template
1278 declarations with the same name, the same parameter-type-list, and
1279 the same template parameter lists cannot be overloaded if any of
1280 them, but not all, have a ref-qualifier.
1282 [namespace.udecl] When a using-declaration brings names
1283 from a base class into a derived class scope, member
1284 functions in the derived class override and/or hide member
1285 functions with the same name and parameter types in a base
1286 class (rather than conflicting). */
1290 /* Compare the quals on the 'this' parm. Don't compare
1291 the whole types, as used functions are treated as
1292 coming from the using class in overload resolution. */
1295 /* Either both or neither need to be ref-qualified for
1296 differing quals to allow overloading. */
1303 /* Handle special correspondence rules for xobj vs xobj and xobj vs iobj
1304 member function declarations.
1305 We don't worry about static member functions here. */
1312 {
1315 };
1316 /* We skip the object parameter below, check it here instead of
1317 making changes to that code. */
1322 }
1325 {
1328 }
1329 else
1335 /* Templates and conversion ops must match return types. */
1340 /* For templates, the template parameters must be identical. */
1342 {
1349 }
1358 /* Bring back parameters omitted from an inherited ctor. The
1359 method and the function can have different omittedness. */
1363 parms2 = (FUNCTION_FIRST_USER_PARMTYPE
1370 {
1372 /* We can't check satisfaction in dependent context, wait until
1373 the class is instantiated. */
1381 /* Member function templates and non-special member functions
1382 coexist if they are not equivalently constrained. A member
1383 function is not hidden by an inherited constructor. */
1386 /* P0848: For special member functions, deleted, unsatisfied, or
1387 less constrained overloads are ineligible. We implement this
1388 by removing them from CLASSTYPE_MEMBER_VEC. Destructors don't
1389 use the notion of eligibility, and the selected destructor can
1390 be deleted, but removing unsatisfied or less constrained
1391 overloads has the same effect as overload resolution. */
1401 else
1404 /* Leave FN in the method vec, discard METHOD. */
1407 {
1408 /* Remove FN, add METHOD. */
1411 }
1412 else
1413 /* Let them coexist for now. */
1415 }
1417 /* If these are versions of the same function, process and
1418 move on. */
1424 {
1426 /* Defer to the other function. */
1432 {
1434 {
1435 /* Inheriting the same constructor along different
1436 paths, combine them. */
1437 SET_DECL_INHERITED_CTOR
1440 /* And discard the new one. */
1442 }
1443 else
1444 /* Inherited ctors can coexist until overload
1445 resolution. */
1447 }
1454 basef);
1456 }
1459 /* Defer to the local function. */
1462 || (flag_new_inheriting_ctors
1464 {
1465 /* Remove the inherited function. */
1468 }
1469 else
1470 {
1476 }
1477 }
1488 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1494 }
1496 /* Subroutines of finish_struct. */
1498 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1499 legit, otherwise return 0. */
1501 static int
1503 {
1504 tree elem;
1512 {
1514 {
1518 else
1521 }
1522 else
1523 {
1524 /* They're changing the access to the same thing they changed
1525 it to before. That's OK. */
1526 ;
1527 }
1528 }
1529 else
1530 {
1532 tf_warning_or_error);
1535 }
1537 }
1539 /* Return the access node for DECL's access in its enclosing class. */
1541 tree
1543 {
1547 }
1549 /* If DECL is a non-dependent using of non-ctor function members, push them
1550 and return true, otherwise return false. Called from
1551 finish_member_declaration. */
1553 bool
1555 {
1562 /* Add the functions to CLASSTYPE_MEMBER_VEC so that overload resolution
1563 works within the class body. */
1565 {
1567 /* Inheriting constructors are handled separately. */
1575 /* If add_method returns false because f was already declared, look
1576 for a duplicate using-declaration. */
1577 else
1582 {
1585 }
1586 }
1588 }
1590 /* Process the USING_DECL, which is a member of T. */
1592 static void
1594 {
1602 /* Handled in maybe_push_used_methods. */
1607 tf_warning_or_error);
1609 {
1614 else
1616 }
1619 ;
1621 {
1628 }
1630 {
1637 }
1642 /* Make type T see field decl FDECL with access ACCESS. */
1644 {
1645 /* C++20 using enum can import non-inherited enumerators into class
1646 scope. We implement that by making a copy of the CONST_DECL for which
1647 CONST_DECL_USING_P is true. */
1654 /* We emitted debug info for the USING_DECL above; make sure we don't
1655 also emit anything for this clone. */
1660 }
1661 else
1663 }
1664 \f
1665 /* Data structure for find_abi_tags_r, below. */
1667 struct abi_tag_data
1668 {
1672 };
1674 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1675 in the context of P. TAG can be either an identifier (the DECL_NAME of
1676 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1678 static void
1680 {
1682 {
1684 {
1685 /* We're collecting tags from template arguments or from
1686 the type of a variable or function return type. */
1689 /* Don't inherit this tag multiple times. */
1693 {
1694 /* Tags inherited from type template arguments are only used
1695 to avoid warnings. */
1698 }
1699 /* For functions and variables we want to warn, too. */
1700 }
1702 /* Otherwise we're diagnosing missing tags. */
1704 {
1705 auto_diagnostic_group d;
1710 }
1712 {
1713 auto_diagnostic_group d;
1717 }
1719 {
1720 auto_diagnostic_group d;
1725 }
1726 else
1727 {
1728 auto_diagnostic_group d;
1732 {
1736 }
1737 }
1738 }
1739 }
1741 /* Find all the ABI tags in the attribute list ATTR and either call
1742 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1744 static void
1746 {
1753 {
1758 else
1760 }
1761 }
1763 /* Find all the ABI tags on T and its enclosing scopes and either call
1764 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1766 static void
1768 {
1770 {
1771 tree attr;
1773 {
1776 }
1777 else
1778 {
1781 }
1783 }
1784 }
1786 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1787 types with ABI tags, add the corresponding identifiers to the VEC in
1788 *DATA and set IDENTIFIER_MARKED. */
1790 static tree
1792 {
1794 /* Tell cp_walk_subtrees to look though typedefs. [PR98481] */
1800 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1801 anyway, but let's make sure of it. */
1809 }
1811 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1812 IDENTIFIER_MARKED on its ABI tags. */
1814 static tree
1816 {
1818 /* Tell cp_walk_subtrees to look though typedefs. */
1824 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1825 anyway, but let's make sure of it. */
1833 }
1835 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1836 scopes. */
1838 static void
1840 {
1843 {
1846 {
1847 /* Template arguments are part of the signature. */
1850 {
1853 }
1854 }
1856 /* A function's parameter types are part of the signature, so
1857 we don't need to inherit any tags that are also in them. */
1862 }
1863 }
1865 /* Check that T has all the ABI tags that subobject SUBOB has, or
1866 warn if not. If T is a (variable or function) declaration, also
1867 return any missing tags, and add them to T if JUST_CHECKING is false. */
1869 static tree
1871 {
1879 /* No need to worry about things local to this TU. */
1895 {
1898 }
1899 else
1900 {
1904 else
1907 }
1912 }
1914 /* Check that DECL has all the ABI tags that are used in parts of its type
1915 that are not reflected in its mangled name. */
1917 void
1919 {
1926 }
1928 /* Return any ABI tags that are used in parts of the type of DECL
1929 that are not reflected in its mangled name. This function is only
1930 used in backward-compatible mangling for ABI <11. */
1932 tree
1934 {
1938 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1939 that we can use this function for setting need_abi_warning
1940 regardless of the current flag_abi_version. */
1943 else
1945 }
1947 void
1949 {
1959 {
1962 {
1966 }
1967 }
1969 // If we found some tags on our template arguments, add them to our
1970 // abi_tag attribute.
1972 {
1976 else
1979 }
1982 }
1984 /* Return true, iff class T has a non-virtual destructor that is
1985 accessible from outside the class heirarchy (i.e. is public, or
1986 there's a suitable friend. */
1988 static bool
1990 {
1993 /* An implicitly declared destructor is always public. And,
1994 if it were virtual, we would have created it by now. */
2009 }
2011 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
2012 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
2013 properties of the bases. */
2015 static void
2019 {
2023 tree base_binfo;
2024 tree binfo;
2034 {
2043 /* If any base class is non-literal, so is the derived class. */
2047 /* If the base class doesn't have copy constructors or
2048 assignment operators that take const references, then the
2049 derived class cannot have such a member automatically
2050 generated. */
2059 /* A virtual base does not effect nearly emptiness. */
2060 ;
2062 {
2064 /* And if there is more than one nearly empty base, then the
2065 derived class is not nearly empty either. */
2067 else
2068 /* Remember we've seen one. */
2070 }
2072 /* If the base class is not empty or nearly empty, then this
2073 class cannot be nearly empty. */
2076 /* A lot of properties from the bases also apply to the derived
2077 class. */
2094 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
2097 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
2103 /* A standard-layout class is a class that:
2104 ...
2105 * has no non-standard-layout base classes, */
2108 {
2109 tree basefield;
2110 /* ...has no base classes of the same type as the first non-static
2111 data member... */
2113 && (same_type_ignoring_top_level_qualifiers_p
2116 /* DR 1813:
2117 ...has at most one base class subobject of any given type... */
2120 else
2121 /* ...has all non-static data members and bit-fields in the class
2122 and its base classes first declared in the same class. */
2128 {
2131 else
2134 }
2135 }
2137 /* Don't bother collecting tm attributes if transactional memory
2138 support is not enabled. */
2140 {
2144 }
2147 }
2149 /* If one of the base classes had TM attributes, and the current class
2150 doesn't define its own, then the current class inherits one. */
2152 {
2155 }
2156 }
2158 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
2159 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
2160 that have had a nearly-empty virtual primary base stolen by some
2161 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
2162 T. */
2164 static void
2166 {
2170 tree base_binfo;
2172 /* Determine the primary bases of our bases. */
2175 {
2178 /* See if we're the non-virtual primary of our inheritance
2179 chain. */
2181 {
2188 /* We are the primary binfo. */
2190 }
2191 /* Determine if we have a virtual primary base, and mark it so.
2192 */
2194 {
2198 /* Someone already claimed this base. */
2200 else
2201 {
2202 tree delta;
2207 /* A virtual binfo might have been copied from within
2208 another hierarchy. As we're about to use it as a
2209 primary base, make sure the offsets match. */
2217 }
2218 }
2219 }
2221 /* First look for a dynamic direct non-virtual base. */
2223 {
2227 {
2230 }
2231 }
2233 /* A "nearly-empty" virtual base class can be the primary base
2234 class, if no non-virtual polymorphic base can be found. Look for
2235 a nearly-empty virtual dynamic base that is not already a primary
2236 base of something in the hierarchy. If there is no such base,
2237 just pick the first nearly-empty virtual base. */
2243 {
2245 {
2246 /* Found one that is not primary. */
2249 }
2251 /* Remember the first candidate. */
2253 }
2255 found:
2256 /* If we've got a primary base, use it. */
2258 {
2263 /* We are stealing a primary base. */
2267 {
2268 tree delta;
2271 /* A virtual binfo might have been copied from within
2272 another hierarchy. As we're about to use it as a primary
2273 base, make sure the offsets match. */
2278 }
2285 }
2286 }
2288 /* Update the variant types of T. */
2290 void
2292 {
2297 variant;
2299 {
2300 /* These fields are in the _TYPE part of the node, not in
2301 the TYPE_LANG_SPECIFIC component, so they are not shared. */
2312 /* Copy whatever these are holding today. */
2322 {
2325 }
2330 }
2331 }
2333 /* KLASS is a class that we're applying may_alias to after the body is
2334 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
2335 canonical type(s) will be implicitly updated. */
2337 static void
2339 {
2348 }
2350 /* Early variant fixups: we apply attributes at the beginning of the class
2351 definition, and we need to fix up any variants that have already been
2352 made via elaborated-type-specifier so that check_qualified_type works. */
2354 void
2356 {
2357 tree variants;
2372 variants;
2374 {
2375 /* These are the two fields that check_qualified_type looks at and
2376 are affected by attributes. */
2381 else
2387 }
2388 }
2389 \f
2390 /* Set memoizing fields and bits of T (and its variants) for later
2391 use. */
2393 static void
2395 {
2396 /* Fix up variants (if any). */
2400 /* For a class w/o baseclasses, 'finish_struct' has set
2401 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2402 Similarly for a class whose base classes do not have vtables.
2403 When neither of these is true, we might have removed abstract
2404 virtuals (by providing a definition), added some (by declaring
2405 new ones), or redeclared ones from a base class. We need to
2406 recalculate what's really an abstract virtual at this point (by
2407 looking in the vtables). */
2410 /* If this type has a copy constructor or a destructor, force its
2411 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2412 nonzero. This will cause it to be passed by invisible reference
2413 and prevent it from being returned in a register. */
2416 {
2417 tree variants;
2420 {
2423 }
2424 }
2425 }
2427 /* Issue warnings about T having private constructors, but no friends,
2428 and so forth.
2430 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2431 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2432 non-private static member functions. */
2434 static void
2436 {
2442 /* If the class has friends, those entities might create and
2443 access instances, so we should not warn. */
2446 /* We will have warned when the template was declared; there's
2447 no need to warn on every instantiation. */
2449 /* There's no reason to even consider warning about this
2450 class. */
2453 /* We only issue one warning, if more than one applies, because
2454 otherwise, on code like:
2456 class A {
2457 // Oops - forgot `public:'
2458 A();
2459 A(const A&);
2460 ~A();
2461 };
2463 we warn several times about essentially the same problem. */
2465 /* Check to see if all (non-constructor, non-destructor) member
2466 functions are private. (Since there are no friends or
2467 non-private statics, we can't ever call any of the private member
2468 functions.) */
2477 /* We're not interested in compiler-generated methods; they don't
2480 {
2482 /* A non-private static member function is just like a
2483 friend; it can create and invoke private member
2484 functions, and be accessed without a class
2485 instance. */
2489 /* Keep searching for a static member function. */
2490 }
2495 {
2496 /* There are no non-private methods, and there's at least one
2497 private member function that isn't a constructor or
2498 destructor. (If all the private members are
2499 constructors/destructors we want to use the code below that
2500 issues error messages specifically referring to
2501 constructors/destructors.) */
2507 {
2510 }
2512 {
2516 }
2517 }
2519 /* Even if some of the member functions are non-private, the class
2520 won't be useful for much if all the constructors or destructors
2521 are private: such an object can never be created or destroyed. */
2524 {
2527 t);
2529 }
2531 /* Warn about classes that have private constructors and no friends. */
2533 /* Implicitly generated constructors are always public. */
2535 {
2538 /* If a non-template class does not define a copy
2539 constructor, one is defined for it, enabling it to avoid
2540 this warning. For a template class, this does not
2541 happen, and so we would normally get a warning on:
2543 template <class T> class C { private: C(); };
2545 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2546 complete non-template or fully instantiated classes have this
2547 flag set. */
2550 else
2555 /* Ideally, we wouldn't count any constructor that takes
2556 an argument of the class type as a parameter, because
2557 such things cannot be used to construct an instance of
2558 the class unless you already have one. */
2560 else
2561 {
2564 }
2567 {
2569 "%q#T only defines private constructors and has "
2576 }
2577 }
2578 }
2580 /* Make BINFO's vtable have N entries, including RTTI entries,
2581 vbase and vcall offsets, etc. Set its type and call the back end
2582 to lay it out. */
2584 static void
2586 {
2587 tree atype;
2588 tree vtable;
2593 /* We may have to grow the vtable. */
2596 {
2600 }
2601 }
2603 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2604 have the same signature. */
2606 int
2608 {
2609 /* One destructor overrides another if they are the same kind of
2610 destructor. */
2614 /* But a non-destructor never overrides a destructor, nor vice
2615 versa, nor do different kinds of destructors override
2616 one-another. For example, a complete object destructor does not
2617 override a deleting destructor. */
2626 {
2634 }
2636 }
2638 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2639 subobject. */
2641 static bool
2643 {
2644 tree probe;
2647 {
2651 /* If we meet a virtual base, we can't follow the inheritance
2652 any more. See if the complete type of DERIVED contains
2653 such a virtual base. */
2656 }
2658 }
2661 /* The function for which we are trying to find a final overrider. */
2662 tree fn;
2663 /* The base class in which the function was declared. */
2664 tree declaring_base;
2665 /* The candidate overriders. */
2666 tree candidates;
2667 /* Path to most derived. */
2669 };
2671 /* Add the overrider along the current path to FFOD->CANDIDATES.
2672 Returns true if an overrider was found; false otherwise. */
2674 static bool
2678 {
2679 tree method;
2681 /* If BINFO is not the most derived type, try a more derived class.
2682 A definition there will overrider a definition here. */
2684 {
2685 depth--;
2689 }
2693 {
2696 /* Remove any candidates overridden by this new function. */
2698 {
2699 /* If *CANDIDATE overrides METHOD, then METHOD
2700 cannot override anything else on the list. */
2703 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2706 else
2708 }
2710 /* Add the new function. */
2713 }
2716 }
2718 /* Called from find_final_overrider via dfs_walk. */
2720 static tree
2722 {
2730 }
2732 static tree
2734 {
2739 }
2741 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2742 FN and whose TREE_VALUE is the binfo for the base where the
2743 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2744 DERIVED) is the base object in which FN is declared. */
2746 static tree
2748 {
2749 find_final_overrider_data ffod;
2751 /* Getting this right is a little tricky. This is valid:
2753 struct S { virtual void f (); };
2754 struct T { virtual void f (); };
2755 struct U : public S, public T { };
2757 even though calling `f' in `U' is ambiguous. But,
2759 struct R { virtual void f(); };
2760 struct S : virtual public R { virtual void f (); };
2761 struct T : virtual public R { virtual void f (); };
2762 struct U : public S, public T { };
2764 is not -- there's no way to decide whether to put `S::f' or
2765 `T::f' in the vtable for `R'.
2767 The solution is to look at all paths to BINFO. If we find
2768 different overriders along any two, then there is a problem. */
2772 /* Determine the depth of the hierarchy. */
2781 /* If there was no winner, issue an error message. */
2786 }
2788 /* Return the index of the vcall offset for FN when TYPE is used as a
2789 virtual base. */
2791 static tree
2793 {
2795 tree_pair_p p;
2803 /* There should always be an appropriate index. */
2805 }
2807 /* Given a DECL_VINDEX of a virtual function found in BINFO, return the final
2808 overrider at that index in the vtable. This should only be used when we
2809 know that BINFO is correct for the dynamic type of the object. */
2811 tree
2813 {
2818 /* BINFO_VIRTUALS in a primary base isn't accurate, find the derived
2819 class that actually owns the vtable. */
2823 }
2825 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2826 dominated by T. FN is the old function; VIRTUALS points to the
2827 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2828 of that entry in the list. */
2830 static void
2833 {
2834 tree b;
2835 tree overrider;
2836 tree delta;
2837 tree virtual_base;
2838 tree first_defn;
2844 /* Find the nearest primary base (possibly binfo itself) which defines
2845 this function; this is the class the caller will convert to when
2846 calling FN through BINFO. */
2848 {
2853 /* The nearest definition is from a lost primary. */
2856 }
2859 /* Find the final overrider. */
2862 {
2865 }
2868 /* Check for adjusting covariant return types. */
2876 /* If the overrider is invalid, don't even try. */
2878 {
2879 /* If FN is a covariant thunk, we must figure out the adjustment
2880 to the final base FN was converting to. As OVERRIDER_TARGET might
2881 also be converting to the return type of FN, we have to
2882 combine the two conversions here. */
2889 {
2893 }
2894 else
2898 /* Find the equivalent binfo within the return type of the
2899 overriding function. We will want the vbase offset from
2900 there. */
2902 over_return);
2905 {
2906 /* There was no existing virtual thunk (which takes
2907 precedence). So find the binfo of the base function's
2908 return type within the overriding function's return type.
2909 Fortunately we know the covariancy is valid (it
2910 has already been checked), so we can just iterate along
2911 the binfos, which have been chained in inheritance graph
2912 order. Of course it is lame that we have to repeat the
2913 search here anyway -- we should really be caching pieces
2914 of the vtable and avoiding this repeated work. */
2918 /* Find the base binfo within the overriding function's
2919 return type. We will always find a thunk_binfo, except
2920 when the covariancy is invalid (which we will have
2921 already diagnosed). */
2930 /* See if virtual inheritance is involved. */
2932 virtual_offset;
2939 {
2943 {
2944 /* We convert via virtual base. Adjust the fixed
2945 offset to be from there. */
2946 offset =
2950 }
2952 /* There was an existing fixed offset, this must be
2953 from the base just converted to, and the base the
2954 FN was thunking to. */
2956 else
2958 }
2959 }
2962 /* Replace the overriding function with a covariant thunk. We
2963 will emit the overriding function in its own slot as
2964 well. */
2967 }
2968 else
2972 /* If we need a covariant thunk, then we may need to adjust first_defn.
2973 The ABI specifies that the thunks emitted with a function are
2974 determined by which bases the function overrides, so we need to be
2975 sure that we're using a thunk for some overridden base; even if we
2976 know that the necessary this adjustment is zero, there may not be an
2977 appropriate zero-this-adjustment thunk for us to use since thunks for
2978 overriding virtual bases always use the vcall offset.
2980 Furthermore, just choosing any base that overrides this function isn't
2981 quite right, as this slot won't be used for calls through a type that
2982 puts a covariant thunk here. Calling the function through such a type
2983 will use a different slot, and that slot is the one that determines
2984 the thunk emitted for that base.
2986 So, keep looking until we find the base that we're really overriding
2987 in this slot: the nearest primary base that doesn't use a covariant
2988 thunk in this slot. */
2990 {
2992 /* We already know that the overrider needs a covariant thunk. */
2995 {
3002 }
3004 }
3006 /* Assume that we will produce a thunk that convert all the way to
3007 the final overrider, and not to an intermediate virtual base. */
3010 /* See if we can convert to an intermediate virtual base first, and then
3011 use the vcall offset located there to finish the conversion. */
3013 {
3014 /* If we find the final overrider, then we can stop
3015 walking. */
3020 /* If we find a virtual base, and we haven't yet found the
3021 overrider, then there is a virtual base between the
3022 declaring base (first_defn) and the final overrider. */
3024 {
3027 }
3028 }
3030 /* Compute the constant adjustment to the `this' pointer. The
3031 `this' pointer, when this function is called, will point at BINFO
3032 (or one of its primary bases, which are at the same offset). */
3034 /* The `this' pointer needs to be adjusted from the declaration to
3035 the nearest virtual base. */
3040 /* If the nearest definition is in a lost primary, we don't need an
3041 entry in our vtable. Except possibly in a constructor vtable,
3042 if we happen to get our primary back. In that case, the offset
3043 will be zero, as it will be a primary base. */
3045 else
3046 /* The `this' pointer needs to be adjusted from pointing to
3047 BINFO to pointing at the base where the final overrider
3048 appears. */
3059 else
3063 }
3065 /* Called from modify_all_vtables via dfs_walk. */
3067 static tree
3069 {
3071 tree virtuals;
3072 tree old_virtuals;
3076 /* A base without a vtable needs no modification, and its bases
3077 are uninteresting. */
3082 /* Don't do the primary vtable, if it's new. */
3086 /* There's no need to modify the vtable for a non-virtual primary
3087 base; we're not going to use that vtable anyhow. We do still
3088 need to do this for virtual primary bases, as they could become
3089 non-primary in a construction vtable. */
3094 /* Now, go through each of the virtual functions in the virtual
3095 function table for BINFO. Find the final overrider, and update
3096 the BINFO_VIRTUALS list appropriately. */
3099 virtuals;
3103 binfo,
3108 }
3110 /* Update all of the primary and secondary vtables for T. Create new
3111 vtables as required, and initialize their RTTI information. Each
3112 of the functions in VIRTUALS is declared in T and may override a
3113 virtual function from a base class; find and modify the appropriate
3114 entries to point to the overriding functions. Returns a list, in
3115 declaration order, of the virtual functions that are declared in T,
3116 but do not appear in the primary base class vtable, and which
3117 should therefore be appended to the end of the vtable for T. */
3119 static tree
3121 {
3125 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
3129 /* Update all of the vtables. */
3132 /* Add virtual functions not already in our primary vtable. These
3133 will be both those introduced by this class, and those overridden
3134 from secondary bases. It does not include virtuals merely
3135 inherited from secondary bases. */
3137 {
3142 {
3143 /* We don't need to adjust the `this' pointer when
3144 calling this function. */
3148 /* This is a function not already in our vtable. Keep it. */
3150 }
3151 else
3152 /* We've already got an entry for this function. Skip it. */
3154 }
3157 }
3159 /* Get the base virtual function declarations in T that have the
3160 indicated NAME. */
3162 static void
3164 {
3167 /* Find virtual functions in T with the indicated NAME. */
3169 {
3171 {
3174 }
3175 }
3182 {
3185 }
3186 }
3188 /* If this method overrides a virtual method from a base, then mark
3189 this member function as being virtual as well. Do 'final' and
3190 'override' checks too. */
3192 void
3194 {
3196 /* In [temp.mem] we have:
3198 A specialization of a member function template does not
3199 override a virtual function from a base class. */
3202 /* IDENTIFIER_VIRTUAL_P indicates whether the name has ever been
3203 used for a vfunc. That avoids the expensive look_for_overrides
3204 call that when we know there's nothing to find. As conversion
3205 operators for the same type can have distinct identifiers, we
3206 cannot optimize those in that way. */
3210 /* Check staticness after we've checked if we 'override'. */
3212 {
3213 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
3214 the error_mark_node so that we know it is an overriding
3215 function. */
3224 }
3229 {
3230 /* Remember this identifier is virtual name. */
3234 /* It's a new vfunc. */
3239 }
3242 }
3244 /* Warn about hidden virtual functions that are not overridden in t.
3245 We know that constructors and destructors don't apply. */
3247 static void
3249 {
3252 {
3260 tree base_binfo;
3261 tree binfo;
3267 /* Iterate through all of the base classes looking for possibly
3268 hidden functions. */
3271 {
3274 }
3276 /* If there are no functions to hide, continue. */
3280 /* Remove any overridden functions. */
3283 {
3287 {
3288 /* If the method from the base class has the same
3289 signature as the method from the derived class, it
3290 has been overridden. Note that we can't move on
3291 after finding one match: fndecl might override
3292 multiple base fns. */
3296 {
3299 }
3300 }
3303 }
3306 /* All the derived fns override base virtuals. */
3309 /* Now give a warning for all base functions without overriders,
3310 as they are hidden. */
3313 {
3314 auto_diagnostic_group d;
3315 /* Here we know it is a hider, and no overrider exists. */
3317 OPT_Woverloaded_virtual_,
3320 }
3321 }
3322 }
3324 /* Recursive helper for finish_struct_anon. */
3326 static void
3328 {
3330 {
3331 /* We're generally only interested in entities the user
3332 declared, but we also find nested classes by noticing
3333 the TYPE_DECL that we create implicitly. You're
3334 allowed to put one anonymous union inside another,
3335 though, so we explicitly tolerate that. We use
3336 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
3337 we also allow unnamed types used for defining fields. */
3346 /* Recurse into the anonymous aggregates to correctly handle
3347 access control (c++/24926):
3349 class A {
3350 union {
3351 union {
3352 int i;
3353 };
3354 };
3355 };
3357 int j=A().i; */
3361 }
3362 }
3364 /* Fix up any anonymous union/struct members of T. */
3366 static void
3368 {
3370 {
3379 }
3380 }
3382 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
3383 will be used later during class template instantiation.
3384 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
3385 a non-static member data (FIELD_DECL), a member function
3386 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
3387 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
3388 When FRIEND_P is nonzero, T is either a friend class
3389 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
3390 (FUNCTION_DECL, TEMPLATE_DECL). */
3392 void
3394 {
3397 {
3402 }
3403 }
3405 /* This function is called from declare_virt_assop_and_dtor via
3406 dfs_walk_all.
3408 DATA is a type that direcly or indirectly inherits the base
3409 represented by BINFO. If BINFO contains a virtual assignment [copy
3410 assignment or move assigment] operator or a virtual constructor,
3411 declare that function in DATA if it hasn't been already declared. */
3413 static tree
3415 {
3423 /* A base without a vtable needs no modification, and its bases
3424 are uninteresting. */
3428 /* If this is a primary base, then we have already looked at the
3429 virtual functions of its vtable. */
3433 {
3437 {
3442 }
3446 }
3449 }
3451 /* If the class type T has a direct or indirect base that contains a
3452 virtual assignment operator or a virtual destructor, declare that
3453 function in T if it hasn't been already declared. */
3455 static void
3457 {
3465 dfs_declare_virt_assop_and_dtor,
3467 }
3469 /* Declare the inheriting constructor for class T inherited from base
3470 constructor CTOR with the parameter array PARMS of size NPARMS. */
3472 static void
3474 {
3477 /* We don't declare an inheriting ctor that would be a default,
3478 copy or move ctor for derived or base. */
3483 {
3487 }
3496 {
3499 }
3500 }
3502 /* Declare all the inheriting constructors for class T inherited from base
3503 constructor CTOR. */
3505 static void
3507 {
3511 {
3516 }
3521 {
3525 }
3528 {
3529 auto_diagnostic_group d;
3533 }
3534 }
3536 /* Implicitly declare T(). */
3538 static void
3540 {
3545 /* Don't force the declaration to get a hard answer; if the
3546 definition would have made the class non-literal, it will still be
3547 non-literal because of the base or member in question, and that
3548 gives a better diagnostic. */
3550 }
3552 /* Create default constructors, assignment operators, and so forth for
3553 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3554 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3555 the class cannot have a default constructor, copy constructor
3556 taking a const reference argument, or an assignment operator taking
3557 a const reference, respectively. */
3559 static void
3563 {
3564 /* Destructor. */
3566 /* In general, we create destructors lazily. */
3575 /* [class.ctor]
3577 If there is no user-declared constructor for a class, a default
3578 constructor is implicitly declared. */
3582 /* [class.ctor]
3584 If a class definition does not explicitly declare a copy
3585 constructor, one is declared implicitly. */
3587 {
3593 }
3595 /* If there is no assignment operator, one will be created if and
3596 when it is needed. For now, just record whether or not the type
3597 of the parameter to the assignment operator will be a const or
3598 non-const reference. */
3600 {
3606 }
3608 /* We can't be lazy about declaring functions that might override
3609 a virtual function from a base class. */
3612 /* If the class definition does not explicitly declare an == operator
3613 function, but declares a defaulted three-way comparison operator function,
3614 an == operator function is declared implicitly. */
3617 {
3619 NULL_TREE);
3624 else
3625 {
3629 }
3631 }
3634 {
3638 {
3639 /* declare, then remove the decl */
3644 {
3646 /* CWG2799: Inheriting a default constructor gives us a default
3647 constructor, not just an inherited constructor. */
3650 }
3653 }
3654 else
3656 }
3657 }
3659 /* Cache of enum_min_precision values. */
3662 /* Return the minimum precision of a bit-field needed to store all
3663 enumerators of ENUMERAL_TYPE TYPE. */
3665 static int
3667 {
3669 /* For unscoped enums without fixed underlying type and without mode
3670 attribute we can just use precision of the underlying type. */
3686 {
3690 {
3701 }
3702 }
3703 else
3711 }
3713 /* FIELD is a bit-field. We are finishing the processing for its
3714 enclosing type. Issue any appropriate messages and set appropriate
3715 flags. Returns false if an error has been diagnosed. */
3717 static bool
3719 {
3721 tree w;
3723 /* Extract the declared width of the bitfield, which has been
3724 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3727 /* Remove the bit-field width indicator so that the rest of the
3728 compiler does not treat that value as a qualifier. */
3731 /* Detect invalid bit-field type. */
3733 {
3737 }
3738 else
3739 {
3741 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3744 /* detect invalid field size. */
3750 {
3753 }
3755 {
3758 }
3760 {
3763 }
3773 {
3779 }
3780 }
3783 {
3787 }
3788 else
3789 {
3790 /* Non-bit-fields are aligned for their type. */
3794 }
3795 }
3797 /* FIELD is a non bit-field. We are finishing the processing for its
3798 enclosing type T. Issue any appropriate messages and set appropriate
3799 flags. */
3801 static bool
3803 tree t,
3806 {
3810 /* In C++98 an anonymous union cannot contain any fields which would change
3811 the settings of CANT_HAVE_CONST_CTOR and friends. */
3813 ;
3814 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3815 structs. So, we recurse through their fields here. */
3817 {
3822 cant_have_const_ctor,
3823 no_const_asn_ref);
3824 }
3825 /* Check members with class type for constructors, destructors,
3826 etc. */
3828 {
3829 /* Never let anything with uninheritable virtuals
3830 make it through without complaint. */
3834 {
3839 field);
3844 field);
3846 {
3850 }
3851 }
3852 else
3853 {
3866 }
3875 }
3880 /* `build_class_init_list' does not recognize
3881 non-FIELD_DECLs. */
3885 }
3887 /* Check the data members (both static and non-static), class-scoped
3888 typedefs, etc., appearing in the declaration of T. Issue
3889 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3890 declaration order) of access declarations; each TREE_VALUE in this
3891 list is a USING_DECL.
3893 In addition, set the following flags:
3895 EMPTY_P
3896 The class is empty, i.e., contains no non-static data members.
3898 CANT_HAVE_CONST_CTOR_P
3899 This class cannot have an implicitly generated copy constructor
3900 taking a const reference.
3902 CANT_HAVE_CONST_ASN_REF
3903 This class cannot have an implicitly generated assignment
3904 operator taking a const reference.
3906 All of these flags should be initialized before calling this
3907 function. */
3909 static void
3913 {
3916 /* Assume there are no access declarations. */
3918 /* Effective C has things to say about classes with pointer members. */
3920 /* Default initialized members affect the whole class. */
3922 /* Lack of any non-static data member of non-volatile literal
3923 type affects a union. */
3925 /* Standard layout requires all FIELDS have same access. */
3929 {
3933 {
3938 /* Save the access declarations for our caller. */
3947 /* FIXME: We should fold in the checking from check_methods. */
3957 {
3958 /* [class.union]
3960 (C++98) If a union contains a static data member,
3961 ... the program is ill-formed. */
3965 }
3970 {
3971 /* [class.union]
3973 If a union contains ... or a [non-static data] member
3974 of reference type, the program is ill-formed. */
3978 }
3980 data_member:
3981 /* Common VAR_DECL & FIELD_DECL processing. */
3985 /* Template instantiation can cause this. Perhaps this
3986 should be a specific instantiation check? */
3988 {
3992 }
3994 {
3998 }
4001 }
4009 /* If it is not a union and at least one non-static data member is
4010 non-literal, the whole class becomes non-literal. Per Core/1453,
4011 volatile non-static data members and base classes are also not allowed.
4012 If it is a union, we might set CLASSTYPE_LITERAL_P after we've seen all
4013 members.
4014 Note: if the type is incomplete we will complain later on. */
4016 {
4019 else
4021 }
4026 {
4027 /* A standard-layout class is a class that:
4029 ... has the same access control (Clause 11) for all
4030 non-static data members, */
4033 else
4036 /* Aggregates must be public. */
4039 }
4041 /* If this is of reference type, check if it needs an init. */
4043 {
4049 {
4050 /* ARM $12.6.2: [A member initializer list] (or, for an
4051 aggregate, initialization by a brace-enclosed list) is the
4052 only way to initialize non-static const and reference
4053 members. */
4056 }
4057 }
4062 {
4064 {
4066 "ignoring packed attribute because of"
4069 }
4073 }
4077 /* We don't treat zero-width bitfields as making a class
4078 non-empty. */
4079 ;
4082 /* Empty data members also don't make a class non-empty. */
4084 else
4085 {
4086 /* The class is non-empty. */
4088 /* The class is not even nearly empty. */
4090 /* If one of the data members contains an empty class, so
4091 does T. */
4095 }
4097 /* This is used by -Weffc++ (see below). Warn only for pointers
4098 to members which might hold dynamic memory. So do not warn
4099 for pointers to functions or pointers to members. */
4105 {
4110 }
4116 {
4123 }
4126 /* DR 148 now allows pointers to members (which are POD themselves),
4127 to be allowed in POD structs. */
4131 /* A potentially-overlapping non-static data member makes the class
4132 non-layout-POD. */
4141 /* We set DECL_C_BIT_FIELD in grokbitfield.
4142 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
4148 {
4151 {
4155 default_init_member);
4156 }
4158 }
4160 /* Now that we've removed bit-field widths from DECL_INITIAL,
4161 anything left in DECL_INITIAL is an NSDMI that makes the class
4162 non-aggregate in C++11, and non-layout-POD always. */
4164 {
4167 else
4169 }
4172 {
4173 /* If any field is const, the structure type is pseudo-const. */
4178 {
4179 /* ARM $12.6.2: [A member initializer list] (or, for an
4180 aggregate, initialization by a brace-enclosed list) is the
4181 only way to initialize non-static const and reference
4182 members. */
4185 }
4186 }
4187 /* A field that is pseudo-const makes the structure likewise. */
4189 {
4194 }
4196 /* Core issue 80: A non-static data member is required to have a
4197 different name from the class iff the class has a
4198 user-declared constructor. */
4203 }
4205 /* Per CWG 2096, a type is a literal type if it is a union, and at least
4206 one of its non-static data members is of non-volatile literal type. */
4210 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
4211 it should also define a copy constructor and an assignment operator to
4212 implement the correct copy semantic (deep vs shallow, etc.). As it is
4213 not feasible to check whether the constructors do allocate dynamic memory
4214 and store it within members, we approximate the warning like this:
4216 -- Warn only if there are members which are pointers
4217 -- Warn only if there is a non-trivial constructor (otherwise,
4218 there cannot be memory allocated).
4219 -- Warn only if there is a non-trivial destructor. We assume that the
4220 user at least implemented the cleanup correctly, and a destructor
4221 is needed to free dynamic memory.
4223 This seems enough for practical purposes. */
4225 && pointer_member
4229 {
4231 {
4233 {
4238 }
4244 }
4245 }
4247 /* Non-static data member initializers make the default constructor
4248 non-trivial. */
4250 {
4253 }
4255 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
4259 /* Check anonymous struct/anonymous union fields. */
4262 /* We've built up the list of access declarations in reverse order.
4263 Fix that now. */
4265 }
4267 /* If TYPE is an empty class type, records its OFFSET in the table of
4268 OFFSETS. */
4270 static int
4272 {
4273 splay_tree_node n;
4278 /* Record the location of this empty object in OFFSETS. */
4286 type,
4290 }
4292 /* Returns nonzero if TYPE is an empty class type and there is
4293 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
4295 static int
4297 {
4298 splay_tree_node n;
4299 tree t;
4304 /* Record the location of this empty object in OFFSETS. */
4314 {
4322 {
4326 }
4327 }
4330 {
4335 }
4338 }
4340 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
4341 F for every subobject, passing it the type, offset, and table of
4342 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
4343 be traversed.
4345 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
4346 than MAX_OFFSET will not be walked.
4348 If F returns a nonzero value, the traversal ceases, and that value
4349 is returned. Otherwise, returns zero. */
4351 static int
4353 subobject_offset_fn f,
4354 tree offset,
4355 splay_tree offsets,
4356 tree max_offset,
4358 {
4362 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
4363 stop. */
4371 {
4374 }
4377 {
4378 tree field;
4379 tree binfo;
4382 /* Avoid recursing into objects that are not interesting. */
4386 /* Record the location of TYPE. */
4391 /* Iterate through the direct base classes of TYPE. */
4395 {
4396 tree binfo_offset;
4401 tree orig_binfo;
4402 /* We cannot rely on BINFO_OFFSET being set for the base
4403 class yet, but the offsets for direct non-virtual
4404 bases can be calculated by going back to the TYPE. */
4407 offset,
4411 f,
4412 binfo_offset,
4413 offsets,
4414 max_offset,
4418 }
4421 {
4425 /* Iterate through the virtual base classes of TYPE. In G++
4426 3.2, we included virtual bases in the direct base class
4427 loop above, which results in incorrect results; the
4428 correct offsets for virtual bases are only known when
4429 working with the most derived type. */
4433 {
4435 f,
4437 offset,
4439 offsets,
4440 max_offset,
4444 }
4445 else
4446 {
4447 /* We still have to walk the primary base, if it is
4448 virtual. (If it is non-virtual, then it was walked
4449 above.) */
4455 {
4456 r = (walk_subobject_offsets
4461 }
4462 }
4463 }
4465 /* Iterate through the fields of TYPE. */
4470 {
4471 tree field_offset;
4476 f,
4478 offset,
4479 field_offset),
4480 offsets,
4481 max_offset,
4485 }
4486 }
4488 {
4491 tree index;
4493 /* Avoid recursing into objects that are not interesting. */
4496 || !domain
4500 /* Step through each of the elements in the array. */
4504 {
4506 f,
4507 offset,
4508 offsets,
4509 max_offset,
4515 /* If this new OFFSET is bigger than the MAX_OFFSET, then
4516 there's no point in iterating through the remaining
4517 elements of the array. */
4520 }
4521 }
4524 }
4526 /* Return true iff FIELD_DECL DECL is potentially overlapping. */
4528 static bool
4530 {
4531 /* Base fields are actually potentially overlapping, but C++ bases go through
4532 a different code path based on binfos, and ObjC++ base fields are laid out
4533 in objc-act, so we don't want layout_class_type to mess with them. */
4535 {
4538 }
4542 }
4544 /* Return true iff DECL is an empty field, either for an empty base or a
4545 [[no_unique_address]] data member. */
4547 bool
4549 {
4557 /* Empty fields should have size zero. */
4561 }
4563 /* Record all of the empty subobjects of DECL_OR_BINFO. */
4565 static void
4567 splay_tree offsets)
4568 {
4573 {
4579 }
4580 else
4581 {
4586 }
4588 tree max_offset;
4589 /* If recording subobjects for a non-static data member or a
4590 non-empty base class, we do not need to record offsets beyond
4591 the size of the biggest empty class. Additional data members
4592 will go at the end of the class. Additional base classes will go
4593 either at offset zero (if empty, in which case they cannot
4594 overlap with offsets past the size of the biggest empty class) or
4595 at the end of the class.
4597 However, if we are placing an empty base class, then we must record
4598 all offsets, as either the empty class is at offset zero (where
4599 other empty classes might later be placed) or at the end of the
4600 class (where other objects might then be placed, so other empty
4601 subobjects might later overlap). */
4605 else
4609 }
4611 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4612 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4613 virtual bases of TYPE are examined. */
4615 static int
4617 tree offset,
4618 splay_tree offsets,
4620 {
4621 splay_tree_node max_node;
4623 /* Get the node in OFFSETS that indicates the maximum offset where
4624 an empty subobject is located. */
4626 /* If there aren't any empty subobjects, then there's no point in
4627 performing this check. */
4633 vbases_p);
4634 }
4636 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4637 non-static data member of the type indicated by RLI. BINFO is the
4638 binfo corresponding to the base subobject, OFFSETS maps offsets to
4639 types already located at those offsets. This function determines
4640 the position of the DECL. */
4642 static void
4644 tree decl,
4645 tree binfo,
4646 splay_tree offsets)
4647 {
4650 tree type;
4653 {
4654 /* For the purposes of determining layout conflicts, we want to
4655 use the class type of BINFO; TREE_TYPE (DECL) will be the
4656 CLASSTYPE_AS_BASE version, which does not contain entries for
4657 zero-sized bases. */
4660 }
4661 else
4662 {
4665 }
4667 /* Try to place the field. It may take more than one try if we have
4668 a hard time placing the field without putting two objects of the
4669 same type at the same address. */
4671 {
4674 /* Place this field. */
4678 /* We have to check to see whether or not there is already
4679 something of the same type at the offset we're about to use.
4680 For example, consider:
4682 struct S {};
4683 struct T : public S { int i; };
4684 struct U : public S, public T {};
4686 Here, we put S at offset zero in U. Then, we can't put T at
4687 offset zero -- its S component would be at the same address
4688 as the S we already allocated. So, we have to skip ahead.
4689 Since all data members, including those whose type is an
4690 empty class, have nonzero size, any overlap can happen only
4691 with a direct or indirect base-class -- it can't happen with
4692 a data member. */
4693 /* In a union, overlap is permitted; all members are placed at
4694 offset zero. */
4699 {
4700 /* Strip off the size allocated to this field. That puts us
4701 at the first place we could have put the field with
4702 proper alignment. */
4705 /* Bump up by the alignment required for the type. */
4706 rli->bitpos
4712 }
4715 {
4716 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4717 the offset wasn't aligned like a pointer when we started to
4718 layout this field, that affects its position. */
4721 {
4724 "alignment of %qD increased in %<-fabi-version=9%> "
4726 else
4729 decl);
4730 }
4732 }
4733 else
4734 /* There was no conflict. We're done laying out this field. */
4736 }
4738 /* Now that we know where it will be placed, update its
4739 BINFO_OFFSET. */
4741 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4742 this point because their BINFO_OFFSET is copied from another
4743 hierarchy. Therefore, we may not need to add the entire
4744 OFFSET. */
4750 }
4752 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4754 static int
4756 tree offset,
4758 {
4760 }
4762 /* Layout the empty base BINFO. EOC indicates the byte currently just
4763 past the end of the class, and should be correctly aligned for a
4764 class of the type indicated by BINFO; OFFSETS gives the offsets of
4765 the empty bases allocated so far. T is the most derived
4766 type. Return nonzero iff we added it at the end. */
4768 static bool
4770 splay_tree offsets)
4771 {
4772 tree alignment;
4776 tree type;
4778 {
4781 }
4782 else
4783 {
4786 }
4788 /* On some platforms (ARM), even empty classes will not be
4789 byte-aligned. */
4794 /* This routine should only be used for empty classes. */
4799 else
4802 /* This is an empty base class. We first try to put it at offset
4803 zero. */
4807 offset,
4808 offsets,
4810 {
4811 /* That didn't work. Now, we move forward from the next
4812 available spot in the class. */
4816 {
4818 offset,
4819 offsets,
4821 /* We finally found a spot where there's no overlap. */
4824 /* There's overlap here, too. Bump along to the next spot. */
4826 }
4827 }
4830 {
4835 }
4837 {
4842 }
4845 /* Adjust BINFO_OFFSET (binfo) to be exactly OFFSET. */
4848 else
4849 {
4853 }
4856 }
4858 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4859 fields at NEXT_FIELD, and return it. */
4861 static tree
4863 {
4864 /* Create the FIELD_DECL. */
4874 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4876 else
4877 {
4880 }
4891 /* Add the new FIELD_DECL to the list of fields for T. */
4897 }
4899 /* Layout the base given by BINFO in the class indicated by RLI.
4900 *BASE_ALIGN is a running maximum of the alignments of
4901 any base class. OFFSETS gives the location of empty base
4902 subobjects. T is the most derived type. Return nonzero if the new
4903 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4904 *NEXT_FIELD, unless BINFO is for an empty base class.
4906 Returns the location at which the next field should be inserted. */
4911 {
4916 /* This error is now reported in xref_tag, thus giving better
4917 location information. */
4920 /* Place the base class. */
4922 {
4923 tree decl;
4925 /* The containing class is non-empty because it has a non-empty
4926 base class. */
4929 /* Create the FIELD_DECL. */
4932 /* Try to place the field. It may take more than one try if we
4933 have a hard time placing the field without putting two
4934 objects of the same type at the same address. */
4936 }
4937 else
4938 {
4940 /* A nearly-empty class "has no proper base class that is empty,
4941 not morally virtual, and at an offset other than zero." */
4943 {
4946 /* The check above (used in G++ 3.2) is insufficient because
4947 an empty class placed at offset zero might itself have an
4948 empty base at a nonzero offset. */
4950 empty_base_at_nonzero_offset_p,
4951 size_zero_node,
4956 }
4958 /* We used to not create a FIELD_DECL for empty base classes because of
4959 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4960 be a problem anymore. We need them to handle initialization of C++17
4961 aggregate bases. */
4963 {
4969 }
4971 /* An empty virtual base causes a class to be non-empty
4972 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4973 here because that was already done when the virtual table
4974 pointer was created. */
4975 }
4977 /* Record the offsets of BINFO and its base subobjects. */
4981 }
4983 /* Layout all of the non-virtual base classes. Record empty
4984 subobjects in OFFSETS. T is the most derived type. Return nonzero
4985 if the type cannot be nearly empty. The fields created
4986 corresponding to the base classes will be inserted at
4987 *NEXT_FIELD. */
4989 static void
4992 {
4993 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4994 subobjects. */
4999 /* The primary base class is always allocated first. */
5002 {
5003 /* We need to walk BINFO_BASE_BINFO to find the access of the primary
5004 base, if it is direct. Indirect base fields are private. */
5007 {
5010 {
5013 }
5014 }
5016 primary_access,
5018 }
5020 /* Now allocate the rest of the bases. */
5022 {
5025 /* The primary base was already allocated above, so we don't
5026 need to allocate it again here. */
5030 /* Virtual bases are added at the end (a primary virtual base
5031 will have already been added). */
5038 }
5039 }
5041 /* Go through the TYPE_FIELDS of T issuing any appropriate
5042 diagnostics, figuring out which methods override which other
5043 methods, and so forth. */
5045 static void
5047 {
5050 {
5056 /* The name of the field is the original field name
5057 Save this in auxiliary field for later overloading. */
5059 {
5063 }
5069 "%<transaction_safe_dynamic%> may only be specified for "
5071 }
5073 /* Check whether the eligible special member functions (P0848) are
5074 user-provided. add_method arranged that the CLASSTYPE_MEMBER_VEC only
5075 has the eligible ones, unless none are eligible; TYPE_FIELDS also contains
5076 ineligible overloads, which is why this needs to be separate from the loop
5077 above. */
5080 {
5082 {
5083 /* P0848: At the end of the definition of a class, overload
5084 resolution is performed among the prospective destructors declared
5085 in that class with an empty argument list to select the destructor
5086 for the class, also known as the selected destructor. The program
5087 is ill-formed if overload resolution fails. */
5094 auto_diagnostic_group d;
5097 else
5101 /* Arbitrarily prune the overload set to a single function for
5102 sake of error recovery. */
5105 }
5108 }
5111 {
5122 }
5125 {
5136 }
5137 }
5139 /* FN is constructor, destructor or operator function. Clone the
5140 declaration to create a NAME'd variant. NEED_VTT_PARM_P and
5141 OMIT_INHERITED_PARMS_P are relevant if it's a cdtor. */
5143 static tree
5146 {
5147 /* Copy the function. */
5149 /* Reset the function name. */
5153 /* Clone constraints. */
5158 /* There's no pending inline data for this function. */
5163 {
5164 /* The base-class destructor is not virtual. */
5167 }
5169 {
5170 /* Set the operator code. */
5174 /* The operator could be virtual. */
5177 }
5182 /* If there was an in-charge parameter, drop it from the function
5183 type. */
5185 {
5188 /* Skip the `this' parameter. */
5190 /* Skip the in-charge parameter. */
5192 /* And the VTT parm, in a complete [cd]tor. */
5196 {
5197 /* If we're omitting inherited parms, that just leaves the VTT. */
5200 }
5204 parmtypes);
5210 }
5212 /* Copy the function parameters. */
5215 /* Remove the in-charge parameter. */
5217 {
5221 }
5223 /* And the VTT parm, in a complete [cd]tor. */
5225 {
5228 else
5229 {
5233 }
5234 }
5236 /* A base constructor inheriting from a virtual base doesn't get the
5237 arguments. */
5242 {
5245 }
5247 /* Create the RTL for this function. */
5250 /* Regardless of the current scope, this is a member function, so
5251 not at namespace scope. */
5255 }
5257 /* FN is an operator function, create a variant for CODE. */
5259 tree
5261 {
5264 }
5266 /* FN is a constructor or destructor. Clone the declaration to create
5267 a specialized in-charge or not-in-charge version, as indicated by
5268 NAME. */
5270 static tree
5273 {
5274 tree clone;
5276 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
5278 {
5290 }
5291 else
5292 {
5298 }
5300 /* Remember where this function came from. */
5303 /* Make it easy to find the CLONE given the FN. Note the
5304 template_result of a template will be chained this way too. */
5309 }
5311 /* Build the clones of FN, return the number of clones built. These
5312 will be inserted onto DECL_CHAIN of FN. */
5314 void
5317 {
5321 {
5322 /* For each constructor, we need two variants: an in-charge version
5323 and a not-in-charge version. */
5326 base_omits_inherited_p);
5328 }
5329 else
5330 {
5333 /* For each destructor, we need three variants: an in-charge
5334 version, a not-in-charge version, and an in-charge deleting
5335 version. We clone the deleting version first because that
5336 means it will go second on the TYPE_FIELDS list -- and that
5337 corresponds to the correct layout order in the virtual
5338 function table.
5340 For a non-virtual destructor, we do not build a deleting
5341 destructor. */
5343 {
5345 count++;
5346 }
5350 }
5352 /* The original is now an abstract function that is never
5353 emitted. */
5358 {
5361 }
5362 }
5364 /* Produce declarations for all appropriate clones of FN. If
5365 UPDATE_METHODS is true, the clones are added to the
5366 CLASSTYPE_MEMBER_VEC. */
5368 void
5370 {
5371 /* Avoid inappropriate cloning. */
5376 /* Base cdtors need a vtt parm if there are virtual bases. */
5379 /* Base ctor omits inherited parms it needs a vttparm and inherited
5380 from a virtual nase ctor. */
5385 }
5387 /* DECL is an in charge constructor, which is being defined. This will
5388 have had an in class declaration, from whence clones were
5389 declared. An out-of-class definition can specify additional default
5390 arguments. As it is the clones that are involved in overload
5391 resolution, we must propagate the information from the DECL to its
5392 clones. */
5394 void
5396 {
5397 tree clone;
5401 {
5406 /* Skip the 'this' parameter. */
5422 {
5424 {
5428 }
5434 {
5435 /* A default parameter has been added. Adjust the
5436 clone's parameters. */
5440 {
5443 clone_parms);
5445 }
5448 tree type
5451 clone_parms);
5459 }
5460 }
5462 }
5463 }
5465 /* For each of the constructors and destructors in T, create an
5466 in-charge and not-in-charge variant. */
5468 static void
5470 {
5471 /* We do not need to propagate the usingness to the clone, at this
5472 point that is not needed. */
5478 }
5480 /* Deduce noexcept for a destructor DTOR. */
5482 void
5484 {
5487 noexcept_deferred_spec);
5488 }
5490 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
5491 of TYPE for virtual functions which FNDECL overrides. Return a
5492 mask of the tm attributes found therein. */
5494 static int
5496 {
5498 tree base_binfo;
5502 {
5510 {
5514 else
5517 }
5518 else
5520 }
5523 }
5525 /* Subroutine of set_method_tm_attributes. Handle the checks and
5526 inheritance for one virtual method FNDECL. */
5528 static void
5530 {
5531 tree tm_attr;
5536 /* If FNDECL doesn't actually override anything (i.e. T is the
5537 class that first declares FNDECL virtual), then we're done. */
5544 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
5545 tm_pure must match exactly, otherwise no weakening of
5546 tm_safe > tm_callable > nothing. */
5547 /* ??? The tm_pure attribute didn't make the transition to the
5548 multivendor language spec. */
5550 {
5552 {
5555 }
5556 }
5557 /* If the overridden function is tm_pure, then FNDECL must be. */
5560 /* Look for base class combinations that cannot be satisfied. */
5562 {
5568 }
5569 /* If FNDECL did not declare an attribute, then inherit the most
5570 restrictive one. */
5572 {
5574 }
5575 /* Otherwise validate that we're not weaker than a function
5576 that is being overridden. */
5577 else
5578 {
5582 }
5585 err_override:
5589 }
5591 /* For each of the methods in T, propagate a class-level tm attribute. */
5593 static void
5595 {
5598 /* Don't bother collecting tm attributes if transactional memory
5599 support is not enabled. */
5603 /* Process virtual methods first, as they inherit directly from the
5604 base virtual function and also require validation of new attributes. */
5606 {
5607 tree vchain;
5610 {
5615 }
5616 }
5618 /* If the class doesn't have an attribute, nothing more to do. */
5623 /* Any method that does not yet have a tm attribute inherits
5624 the one from the class. */
5629 }
5631 /* Returns true if FN is a default constructor. */
5633 bool
5635 {
5638 }
5640 /* Returns true iff class T has a user-provided constructor that can be called
5641 with more than zero arguments. */
5643 bool
5645 {
5650 {
5656 }
5659 }
5661 /* Returns the defaulted constructor if T has one. Otherwise, returns
5662 NULL_TREE. */
5664 tree
5666 {
5671 {
5677 }
5680 }
5682 /* Returns true iff FN is a user-provided function, i.e. user-declared
5683 and not defaulted at its first declaration. */
5685 bool
5687 {
5692 }
5694 /* Returns true iff class T has a user-provided constructor. */
5696 bool
5698 {
5710 }
5712 /* Returns true iff class T has a user-provided or explicit constructor. */
5714 bool
5716 {
5724 {
5728 }
5731 }
5733 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5734 declared or explicitly defaulted in the class body) default
5735 constructor. */
5737 bool
5739 {
5746 {
5752 }
5755 }
5757 /* TYPE is being used as a virtual base, and has a non-trivial move
5758 assignment. Return true if this is due to there being a user-provided
5759 move assignment in TYPE or one of its subobjects; if there isn't, then
5760 multiple move assignment can't cause any harm. */
5762 bool
5764 {
5765 /* Does the type itself have a user-provided move assignment operator? */
5773 /* Do any of its bases? */
5775 tree base_binfo;
5780 /* Or non-static data members? */
5782 {
5787 }
5789 /* Seems not. */
5791 }
5793 /* If default-initialization leaves part of TYPE uninitialized, returns
5794 a DECL for the field or TYPE itself (DR 253). */
5796 tree
5798 {
5809 {
5813 }
5817 {
5821 }
5824 }
5826 /* Returns true iff for class T, a trivial synthesized default constructor
5827 would be constexpr. */
5829 bool
5831 {
5832 /* A defaulted trivial default constructor is constexpr
5833 if there is nothing to initialize. */
5835 /* A class with a vptr doesn't have a trivial default ctor.
5836 In C++20, a class can have transient uninitialized members, e.g.:
5838 struct S { int i; constexpr S() = default; };
5840 should work. */
5843 }
5845 /* Returns true iff class T has a constexpr default constructor. */
5847 bool
5849 {
5850 tree fns;
5853 {
5854 /* The caller should have stripped an enclosing array. */
5857 }
5859 {
5862 /* Non-trivial, we need to check subobject constructors. */
5864 }
5867 }
5869 /* Returns true iff class T has a constexpr default constructor or has an
5870 implicitly declared default constructor that we can't tell if it's constexpr
5871 without forcing a lazy declaration (which might cause undesired
5872 instantiations). */
5874 static bool
5876 {
5879 /* Assume it's constexpr. */
5882 }
5884 /* Returns true iff class T has a constexpr destructor. */
5886 bool
5888 {
5889 tree fns;
5892 /* Non-trivial, we need to check subobject destructors. */
5896 }
5898 /* Returns true iff class T has a constexpr destructor or has an
5899 implicitly declared destructor that we can't tell if it's constexpr
5900 without forcing a lazy declaration (which might cause undesired
5901 instantiations). */
5903 static bool
5905 {
5906 /* Until C++20, only trivial destruction is constexpr. */
5912 /* Assume it's constexpr. */
5916 }
5918 /* Returns true iff class TYPE has a virtual destructor. */
5920 bool
5922 {
5923 tree dtor;
5931 }
5933 /* True iff class TYPE has a non-deleted trivial default
5934 constructor. */
5937 {
5939 }
5941 /* Returns true iff T, a class, has a move-assignment or
5942 move-constructor. Does not lazily declare either.
5943 If USER_P is false, any move function will do. If it is true, the
5944 move function must be user-declared.
5946 Note that user-declared here is different from "user-provided",
5947 which doesn't include functions that are defaulted in the
5948 class. */
5950 bool
5952 {
5972 }
5974 /* True iff T has a move constructor that is not deleted. */
5976 bool
5978 {
5985 }
5987 /* If T, a class, has a user-provided copy constructor, copy assignment
5988 operator, or destructor, returns that function. Otherwise, null. */
5990 tree
5992 {
5995 {
5999 }
6005 {
6010 }
6013 {
6017 }
6020 }
6022 /* True iff T has a member or friend declaration of operator OP. */
6024 bool
6026 {
6034 }
6037 /* If T has a defaulted member or friend declaration of OP, return it. */
6039 tree
6041 {
6044 {
6048 }
6052 {
6056 }
6058 }
6060 /* Nonzero if we need to build up a constructor call when initializing an
6061 object of this class, either because it has a user-declared constructor
6062 or because it doesn't have a default constructor (so we need to give an
6063 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
6064 what you care about is whether or not an object can be produced by a
6065 constructor (e.g. so we don't set TREE_READONLY on const variables of
6066 such type); use this function when what you care about is whether or not
6067 to try to call a constructor to create an object. The latter case is
6068 the former plus some cases of constructors that cannot be called. */
6070 bool
6072 {
6073 tree inner;
6083 /* A user-declared constructor might be private, and a constructor might
6084 be trivial but deleted. */
6087 {
6094 }
6096 }
6098 /* Like type_build_ctor_call, but for destructors. */
6100 bool
6102 {
6103 tree inner;
6112 /* A user-declared destructor might be private, and a destructor might
6113 be trivial but deleted. */
6116 {
6123 }
6125 }
6127 /* Returns TRUE iff we need a cookie when dynamically allocating an
6128 array whose elements have the indicated class TYPE. */
6130 static bool
6132 {
6133 tree fns;
6138 /* If there's a non-trivial destructor, we need a cookie. In order
6139 to iterate through the array calling the destructor for each
6140 element, we'll have to know how many elements there are. */
6144 /* If the usual deallocation function is a two-argument whose second
6145 argument is of type `size_t', then we have to pass the size of
6146 the array to the deallocation function, so we will need to store
6147 a cookie. */
6151 /* If there are no `operator []' members, or the lookup is
6152 ambiguous, then we don't need a cookie. */
6155 /* Loop through all of the functions. */
6157 {
6160 /* See if this function is a one-argument delete function. If
6161 it is, then it will be the usual deallocation function. */
6165 /* Do not consider this function if its second argument is an
6166 ellipsis. */
6169 /* Otherwise, if we have a two-argument function and the second
6170 argument is `size_t', it will be the usual deallocation
6171 function -- unless there is one-argument function, too. */
6175 }
6178 }
6180 /* Finish computing the `literal type' property of class type T.
6182 At this point, we have already processed base classes and
6183 non-static data members. We need to check whether the copy
6184 constructor is trivial, the destructor is trivial, and there
6185 is a trivial default constructor or at least one constexpr
6186 constructor other than the copy constructor. */
6188 static void
6190 {
6191 tree fn;
6205 /* C++14 DR 1684 removed this restriction. */
6213 {
6216 {
6217 auto_diagnostic_group d;
6219 "enclosing class of %<constexpr%> non-static "
6222 }
6223 }
6224 }
6226 /* T is a non-literal type used in a context which requires a constant
6227 expression. Explain why it isn't literal. */
6229 void
6231 {
6241 /* Already explained. */
6244 auto_diagnostic_group d;
6248 " %qT is a closure type, which is only literal in "
6255 t);
6260 {
6262 " %q+T is not an aggregate, does not have a trivial "
6263 "default constructor, and has no %<constexpr%> constructor that "
6266 /* Note that we can't simply call locate_ctor because when the
6267 constructor is deleted it just returns NULL_TREE. */
6269 {
6276 {
6279 else
6282 }
6283 }
6284 }
6285 else
6286 {
6290 {
6293 {
6299 }
6300 }
6302 {
6303 tree ftype;
6308 {
6311 field);
6314 }
6318 }
6319 }
6320 }
6322 /* Check the validity of the bases and members declared in T. Add any
6323 implicitly-generated functions (like copy-constructors and
6324 assignment operators). Compute various flag bits (like
6325 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
6326 level: i.e., independently of the ABI in use. */
6328 static void
6330 {
6331 /* Nonzero if the implicitly generated copy constructor should take
6332 a non-const reference argument. */
6334 /* Nonzero if the implicitly generated assignment operator
6335 should take a non-const reference argument. */
6337 tree access_decls;
6340 tree fn;
6342 /* By default, we use const reference arguments and generate default
6343 constructors. */
6347 /* Check all the base-classes and set FMEM members to point to arrays
6348 of potential interest. */
6351 /* Deduce noexcept on destructor. This needs to happen after we've set
6352 triviality flags appropriately for our bases, and before checking
6353 overriden virtual functions via check_methods. */
6359 /* Check all the method declarations. */
6362 /* Save the initial values of these flags which only indicate whether
6363 or not the class has user-provided functions. As we analyze the
6364 bases and members we can set these flags for other reasons. */
6368 /* Check all the data member declarations. We cannot call
6369 check_field_decls until we have called check_bases check_methods,
6370 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
6371 being set appropriately. */
6376 /* A nearly-empty class has to be vptr-containing; a nearly empty
6377 class contains just a vptr. */
6381 /* Do some bookkeeping that will guide the generation of implicitly
6382 declared member functions. */
6385 /* We need to call a constructor for this class if it has a
6386 user-provided constructor, or if the default constructor is going
6387 to initialize the vptr. (This is not an if-and-only-if;
6388 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
6389 themselves need constructing.) */
6392 /* [dcl.init.aggr]
6394 An aggregate is an array or a class with no user-provided
6395 constructors ... and no virtual functions.
6397 Again, other conditions for being an aggregate are checked
6398 elsewhere. */
6404 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
6405 retain the old definition internally for ABI reasons. */
6414 /* Is this class non-layout-POD because it wasn't an aggregate in C++98? */
6416 {
6418 /* It's non-POD for another reason. */
6422 }
6424 /* If the only explicitly declared default constructor is user-provided,
6425 set TYPE_HAS_COMPLEX_DFLT. */
6431 /* Warn if a public base of a polymorphic type has an accessible
6432 non-virtual destructor. It is only now that we know the class is
6433 polymorphic. Although a polymorphic base will have a already
6434 been diagnosed during its definition, we warn on use too. */
6436 {
6439 tree base_binfo;
6443 {
6451 basetype);
6452 }
6453 }
6455 /* If the class has no user-declared constructor, but does have
6456 non-static const or reference data members that can never be
6457 initialized, issue a warning. */
6459 /* Classes with user-declared constructors are presumed to
6460 initialize these members. */
6462 /* Aggregates can be initialized with brace-enclosed
6463 initializers. */
6465 {
6466 tree field;
6469 {
6470 tree type;
6487 }
6488 }
6490 /* Synthesize any needed methods. */
6492 cant_have_const_ctor,
6493 no_const_asn_ref);
6495 /* Check defaulted declarations here so we have cant_have_const_ctor
6496 and don't need to worry about clones. */
6501 {
6502 /* ...except handle comparisons later, in finish_struct_1. */
6508 {
6509 bool imp_const_p
6515 /* If the function is defaulted outside the class, we just
6516 give the synthesis error. Core Issue #1331 says this is
6517 no longer ill-formed, it is defined as deleted instead. */
6519 }
6521 }
6524 /* "This class type is not an aggregate." */
6527 /* Compute the 'literal type' property before we
6528 do anything with non-static member functions. */
6531 /* Create the in-charge and not-in-charge variants of constructors
6532 and destructors. */
6535 /* Process the using-declarations. */
6539 /* Figure out whether or not we will need a cookie when dynamically
6540 allocating an array of this type. */
6544 /* Classes marked hot or cold propagate the attribute to all members. We
6545 may do this now that methods are declared. This does miss some lazily
6546 declared special member functions (CLASSTYPE_LAZY_*), which are handled
6547 in lazily_declare_fn later on. */
6549 }
6551 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
6552 accordingly. If a new vfield was created (because T doesn't have a
6553 primary base class), then the newly created field is returned. It
6554 is not added to the TYPE_FIELDS list; it is the caller's
6555 responsibility to do that. Accumulate declared virtual functions
6556 on VIRTUALS_P. */
6558 static tree
6560 {
6561 tree fn;
6563 /* Collect the virtual functions declared in T. */
6568 {
6577 }
6579 /* If we couldn't find an appropriate base class, create a new field
6580 here. Even if there weren't any new virtual functions, we might need a
6581 new virtual function table if we're supposed to include vptrs in
6582 all classes that need them. */
6584 {
6585 /* We build this decl with vtbl_ptr_type_node, which is a
6586 `vtable_entry_type*'. It might seem more precise to use
6587 `vtable_entry_type (*)[N]' where N is the number of virtual
6588 functions. However, that would require the vtable pointer in
6589 base classes to have a different type than the vtable pointer
6590 in derived classes. We could make that happen, but that
6591 still wouldn't solve all the problems. In particular, the
6592 type-based alias analysis code would decide that assignments
6593 to the base class vtable pointer can't alias assignments to
6594 the derived class vtable pointer, since they have different
6595 types. Thus, in a derived class destructor, where the base
6596 class constructor was inlined, we could generate bad code for
6597 setting up the vtable pointer.
6599 Therefore, we use one type for all vtable pointers. We still
6600 use a type-correct type; it's just doesn't indicate the array
6601 bounds. That's better than using `void*' or some such; it's
6602 cleaner, and it let's the alias analysis code know that these
6603 stores cannot alias stores to void*! */
6604 tree field;
6617 /* This class is non-empty. */
6621 }
6624 }
6626 /* Add OFFSET to all base types of BINFO which is a base in the
6627 hierarchy dominated by T.
6629 OFFSET, which is a type offset, is number of bytes. */
6631 static void
6633 {
6635 tree primary_binfo;
6636 tree base_binfo;
6638 /* Update BINFO's offset. */
6643 offset));
6645 /* Find the primary base class. */
6651 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
6652 downwards. */
6654 {
6655 /* Don't do the primary base twice. */
6663 }
6664 }
6666 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
6667 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
6668 empty subobjects of T. */
6670 static void
6672 {
6673 tree vbase;
6680 /* Find the last field. The artificial fields created for virtual
6681 bases will go after the last extant field to date. */
6686 /* Go through the virtual bases, allocating space for each virtual
6687 base that is not already a primary base class. These are
6688 allocated in inheritance graph order. */
6690 {
6695 {
6696 /* This virtual base is not a primary base of any class in the
6697 hierarchy, so we have to add space for it. */
6699 access_private_node,
6701 }
6702 }
6703 }
6705 /* Returns the offset of the byte just past the end of the base class
6706 BINFO. */
6708 static tree
6710 {
6711 tree size;
6716 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
6717 allocate some space for it. It cannot have virtual bases, so
6718 TYPE_SIZE_UNIT is fine. */
6720 else
6724 }
6726 /* Returns one of three variations of the ending offset of T. If MODE is
6727 eoc_nvsize, the result is the ABI "nvsize" (i.e. sizeof before allocating
6728 vbases). If MODE is eoc_vsize, the result is the sizeof after allocating
6729 vbases but before rounding, which is not named in the ABI. If MODE is
6730 eoc_nv_or_dsize, the result is the greater of "nvsize" and "dsize" (the size
6731 of the actual data in the class, kinda), as used for allocation of
6732 potentially-overlapping fields. */
6735 static tree
6737 {
6740 tree binfo;
6741 tree base_binfo;
6742 tree offset;
6747 {
6756 }
6761 {
6764 /* DECL_SIZE_UNIT can be null for a flexible array. */
6768 /* For empty fields DECL_SIZE_UNIT is 0, but we want the
6769 size of the type (usually 1) for computing nvsize. */
6773 {
6778 }
6779 else
6783 }
6788 {
6790 /* For dsize, don't count trailing empty bases. */
6793 else
6797 }
6800 }
6802 /* Warn as appropriate about the change in whether we pack into the tail
6803 padding of FIELD, a base field which has a C++14 aggregate type with default
6804 member initializers. */
6806 static void
6808 {
6828 {
6832 "%<-std=c++14%> and up changes in "
6834 else
6836 "%<-std=c++14%> and up changes in "
6838 }
6839 }
6841 /* Warn about bases of T that are inaccessible because they are
6842 ambiguous. For example:
6844 struct S {};
6845 struct T : public S {};
6846 struct U : public S, public T {};
6848 Here, `(S*) new U' is not allowed because there are two `S'
6849 subobjects of U. */
6851 static void
6853 {
6856 tree basetype;
6857 tree binfo;
6858 tree base_binfo;
6860 /* If not checking for warning then return early. */
6864 /* If there are no repeated bases, nothing can be ambiguous. */
6868 /* Check direct bases. */
6871 {
6877 }
6879 /* Check for ambiguous virtual bases. */
6883 {
6889 }
6890 }
6892 /* Compare two INTEGER_CSTs K1 and K2. */
6894 static int
6896 {
6898 }
6900 /* Increase the size indicated in RLI to account for empty classes
6901 that are "off the end" of the class. */
6903 static void
6905 {
6906 tree eoc;
6907 tree rli_size;
6909 /* It might be the case that we grew the class to allocate a
6910 zero-sized base class. That won't be reflected in RLI, yet,
6911 because we are willing to overlay multiple bases at the same
6912 offset. However, now we need to make sure that RLI is big enough
6913 to reflect the entire class. */
6918 {
6919 /* The size should have been rounded to a whole byte. */
6922 rli->bitpos
6931 }
6932 }
6934 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
6935 BINFO_OFFSETs for all of the base-classes. Position the vtable
6936 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
6938 static void
6940 {
6941 tree non_static_data_members;
6942 tree field;
6943 tree vptr;
6944 record_layout_info rli;
6945 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6946 types that appear at that offset. */
6947 splay_tree empty_base_offsets;
6948 /* True if the last field laid out was a bit-field. */
6950 /* The location at which the next field should be inserted. */
6953 /* Keep track of the first non-static data member. */
6956 /* Start laying out the record. */
6959 /* Mark all the primary bases in the hierarchy. */
6962 /* Create a pointer to our virtual function table. */
6965 /* The vptr is always the first thing in the class. */
6967 {
6972 }
6973 else
6976 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6981 /* Layout the non-static data members. */
6983 {
6984 tree type;
6985 tree padding;
6987 /* We still pass things that aren't non-static data members to
6988 the back end, in case it wants to do something with them. */
6990 {
6992 /* If the static data member has incomplete type, keep track
6993 of it so that it can be completed later. (The handling
6994 of pending statics in finish_record_layout is
6995 insufficient; consider:
6997 struct S1;
6998 struct S2 { static S1 s1; };
7000 At this point, finish_record_layout will be called, but
7001 S1 is still incomplete.) */
7003 {
7005 /* The visibility of static data members is determined
7006 at their point of declaration, not their point of
7007 definition. */
7009 }
7011 }
7023 {
7024 /* if D is a potentially-overlapping data member, update sizeof(C) to
7025 max (sizeof(C), offset(D)+max (nvsize(D), dsize(D))). */
7028 else
7029 {
7033 }
7034 }
7036 /* If this field is a bit-field whose width is greater than its
7037 type, then there are some special rules for allocating
7038 it. */
7041 {
7043 /* We must allocate the bits as if suitably aligned for the
7044 longest integer type that fits in this many bits. Then,
7045 we are supposed to use the left over bits as additional
7046 padding. */
7048 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
7056 {
7058 /* Too big, so our current guess is what we want. */
7060 /* Not bigger than limit, ok */
7062 }
7064 /* Figure out how much additional padding is required. */
7066 /* In a union, the padding field must have the full width
7067 of the bit-field; all fields start at offset zero. */
7069 else
7076 /* An unnamed bitfield does not normally affect the
7077 alignment of the containing class on a target where
7078 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
7079 make any exceptions for unnamed bitfields when the
7080 bitfields are longer than their types. Therefore, we
7081 temporarily give the field a name. */
7083 {
7086 }
7092 empty_base_offsets);
7095 /* Now that layout has been performed, set the size of the
7096 field to the size of its declared type; the rest of the
7097 field is effectively invisible. */
7099 /* We must also reset the DECL_MODE of the field. */
7101 }
7103 {
7106 }
7107 else
7109 empty_base_offsets);
7111 /* Remember the location of any empty classes in FIELD. */
7114 /* If a bit-field does not immediately follow another bit-field,
7115 and yet it starts in the middle of a byte, we have failed to
7116 comply with the ABI. */
7119 /* The TREE_NO_WARNING flag gets set by Objective-C when
7120 laying out an Objective-C class. The ObjC ABI differs
7121 from the C++ ABI, and so we do not want a warning
7122 here. */
7124 && !last_field_was_bitfield
7127 bitsize_unit_node)))
7129 "offset of %qD is not ABI-compliant and may "
7132 /* The middle end uses the type of expressions to determine the
7133 possible range of expression values. In order to optimize
7134 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
7135 must be made aware of the width of "i", via its type.
7137 Because C++ does not have integer types of arbitrary width,
7138 we must (for the purposes of the front end) convert from the
7139 type assigned here to the declared type of the bitfield
7140 whenever a bitfield expression is used as an rvalue.
7141 Similarly, when assigning a value to a bitfield, the value
7142 must be converted to the type given the bitfield here. */
7144 {
7149 {
7156 }
7157 }
7159 /* If we needed additional padding after this field, add it
7160 now. */
7162 {
7163 tree padding_field;
7166 FIELD_DECL,
7167 NULL_TREE,
7168 char_type_node);
7176 NULL_TREE,
7177 empty_base_offsets);
7178 }
7181 }
7184 {
7185 /* Make sure that we are on a byte boundary so that the size of
7186 the class without virtual bases will always be a round number
7187 of bytes. */
7190 }
7192 /* We used to remove zero width bitfields at this point since PR42217,
7193 while the C FE never did that. That caused ABI differences on various
7194 targets. Set the DECL_FIELD_CXX_ZERO_WIDTH_BIT_FIELD flag on them
7195 instead, so that the backends can emit -Wpsabi warnings in the cases
7196 where the ABI changed. */
7198 {
7201 /* We should not be confused by the fact that grokbitfield
7202 temporarily sets the width of the bit field into
7203 DECL_BIT_FIELD_REPRESENTATIVE (field).
7204 check_bitfield_decl eventually sets DECL_SIZE (field)
7205 to that width. */
7211 }
7214 {
7215 /* T needs a different layout as a base (eliding virtual bases
7216 or whatever). Create that version. */
7225 /* If the ABI version is not at least two, and the last
7226 field was a bit-field, RLI may not be on a byte
7227 boundary. In particular, rli_size_unit_so_far might
7228 indicate the last complete byte, while rli_size_so_far
7229 indicates the total number of bits used. Therefore,
7230 rli_size_so_far, rather than rli_size_unit_so_far, is
7231 used to compute TYPE_SIZE_UNIT. */
7233 /* Set the size and alignment for the new type. */
7241 eoc);
7253 /* Copy the non-static data members of T. This will include its
7254 direct non-virtual bases & vtable. */
7258 {
7260 /* Zap any NSDMI, it's not needed and might be a deferred
7261 parse. */
7265 }
7268 /* We use the base type for trivial assignments, and hence it
7269 needs a mode. */
7272 /* Record the base version of the type. */
7274 }
7275 else
7278 /* Every empty class contains an empty class. */
7282 /* Set the TYPE_DECL for this type to contain the right
7283 value for DECL_OFFSET, so that we can use it as part
7284 of a COMPONENT_REF for multiple inheritance. */
7287 /* Now fix up any virtual base class types that we left lying
7288 around. We must get these done before we try to lay out the
7289 virtual function table. As a side-effect, this will remove the
7290 base subobject fields. */
7293 /* Make sure that empty classes are reflected in RLI at this
7294 point. */
7297 /* Make sure not to create any structures with zero size. */
7303 /* If this is a non-POD, declaring it packed makes a difference to how it
7304 can be used as a field; don't let finalize_record_size undo it. */
7308 /* Let the back end lay out the type. */
7311 /* If we didn't end up needing an as-base type, don't use it. */
7313 /* If T's CLASSTYPE_AS_BASE is TYPE_USER_ALIGN, but T is not,
7314 replacing the as-base type would change CLASSTYPE_USER_ALIGN,
7315 causing us to lose the user-specified alignment as in PR94050. */
7327 /* Warn about bases that can't be talked about due to ambiguity. */
7330 /* Now that we're done with layout, give the base fields the real types. */
7335 /* Clean up. */
7342 }
7344 /* Determine the "key method" for the class type indicated by TYPE,
7345 and set CLASSTYPE_KEY_METHOD accordingly. */
7347 void
7349 {
7350 tree method;
7357 /* The key method is the first non-pure virtual function that is not
7358 inline at the point of class definition. On some targets the
7359 key function may not be inline; those targets should not call
7360 this function until the end of the translation unit. */
7366 {
7369 }
7372 }
7374 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
7375 class data member of non-zero size, otherwise false. */
7379 {
7387 {
7391 }
7394 }
7396 /* Used by find_flexarrays and related functions. */
7398 struct flexmems_t
7399 {
7400 /* The first flexible array member or non-zero array member found
7401 in the order of layout. */
7402 tree array;
7403 /* First non-static non-empty data member in the class or its bases. */
7404 tree first;
7405 /* The first non-static non-empty data member following either
7406 the flexible array member, if found, or the zero-length array member
7407 otherwise. AFTER[1] refers to the first such data member of a union
7408 of which the struct containing the flexible array member or zero-length
7409 array is a member, or NULL when no such union exists. This element is
7410 only used during searching, not for diagnosing problems. AFTER[0]
7411 refers to the first such data member that is not a member of such
7412 a union. */
7415 /* Refers to a struct (not union) in which the struct of which the flexible
7416 array is member is defined. Used to diagnose strictly (according to C)
7417 invalid uses of the latter structs. */
7418 tree enclosing;
7419 };
7421 /* Find either the first flexible array member or the first zero-length
7422 array, in that order of preference, among members of class T (but not
7423 its base classes), and set members of FMEM accordingly.
7424 BASE_P is true if T is a base class of another class.
7425 PUN is set to the outermost union in which the flexible array member
7426 (or zero-length array) is defined if one such union exists, otherwise
7427 to NULL.
7428 Similarly, PSTR is set to a data member of the outermost struct of
7429 which the flexible array is a member if one such struct exists,
7430 otherwise to NULL. */
7432 static void
7436 {
7437 /* Set the "pointer" to the outermost enclosing union if not set
7438 yet and maintain it for the remainder of the recursion. */
7443 {
7447 /* Is FLD a typedef for an anonymous struct? */
7449 /* FIXME: Note that typedefs (as well as arrays) need to be fully
7450 handled elsewhere so that errors like the following are detected
7451 as well:
7452 typedef struct { int i, a[], j; } S; // bug c++/72753
7453 S s [2]; // bug c++/68489
7454 */
7459 {
7460 /* Check the nested unnamed type referenced via a typedef
7461 independently of FMEM (since it's not a data member of
7462 the enclosing class). */
7465 }
7467 /* Skip anything that's GCC-generated or not a (non-static) data
7468 member. */
7472 /* Type of the member. */
7477 /* Determine the type of the array element or object referenced
7478 by the member so that it can be checked for flexible array
7479 members if it hasn't been yet. */
7486 {
7488 {
7489 /* Once the member after the flexible array has been found
7490 we're done. */
7493 }
7496 {
7497 /* Descend into the non-static member struct or union and try
7498 to find a flexible array member or zero-length array among
7499 its members. This is only necessary for anonymous types
7500 and types in whose context the current type T has not been
7501 defined (the latter must not be checked again because they
7502 are already in the process of being checked by one of the
7503 recursive calls). */
7508 /* If this member isn't anonymous and a prior non-flexible array
7509 member has been seen in one of the enclosing structs, clear
7510 the FIRST member since it doesn't contribute to the flexible
7511 array struct's members. */
7522 {
7523 /* Restore the FIRST member reset above if no flexible
7524 array member has been found in this member's struct. */
7526 }
7528 /* If the member struct contains the first flexible array
7529 member, or if this member is a base class, continue to
7530 the next member and avoid setting the FMEM->NEXT pointer
7531 to point to it. */
7534 }
7535 }
7538 {
7539 /* Remember the first non-static data member. */
7543 /* Remember the first non-static data member after the flexible
7544 array member, if one has been found, or the zero-length array
7545 if it has been found. */
7548 }
7550 /* Skip non-arrays. */
7554 /* Determine the upper bound of the array if it has one. */
7556 {
7558 {
7559 /* Make a record of the zero-length array if either one
7560 such field or a flexible array member has been seen to
7561 handle the pathological and unlikely case of multiple
7562 such members. */
7565 }
7567 {
7568 /* Remember the first zero-length array unless a flexible array
7569 member has already been seen. */
7572 }
7573 }
7574 else
7575 {
7576 /* Flexible array members have no upper bound. */
7578 {
7580 {
7581 /* Replace the zero-length array if it's been stored and
7582 reset the after pointer. */
7586 }
7588 /* Make a record of another flexible array member. */
7590 }
7591 else
7592 {
7595 }
7596 }
7597 }
7598 }
7600 /* Diagnose a strictly (by the C standard) invalid use of a struct with
7601 a flexible array member (or the zero-length array extension). */
7603 static void
7605 {
7607 {
7608 auto_diagnostic_group d;
7619 }
7620 }
7622 /* Issue diagnostics for invalid flexible array members or zero-length
7623 arrays that are not the last elements of the containing class or its
7624 base classes or that are its sole members. */
7626 static void
7628 {
7633 {
7636 }
7638 /* Has a diagnostic been issued? */
7644 {
7651 {
7654 auto_diagnostic_group d;
7656 {
7659 }
7660 }
7661 }
7662 else
7663 {
7670 {
7674 auto_diagnostic_group d;
7677 /* In the unlikely event that the member following the flexible
7678 array member is declared in a different class, or the member
7679 overlaps another member of a common union, point to it.
7680 Otherwise it should be obvious. */
7684 {
7689 }
7690 }
7691 }
7695 }
7698 /* Recursively check to make sure that any flexible array or zero-length
7699 array members of class T or its bases are valid (i.e., not the sole
7700 non-static data member of T and, if one exists, that it is the last
7701 non-static data member of T and its base classes. FMEM is expected
7702 to be initially null and is used internally by recursive calls to
7703 the function. Issue the appropriate diagnostics for the array member
7704 that fails the checks. */
7706 static void
7709 {
7710 /* Initialize the result of a search for flexible array and zero-length
7711 array members. Avoid doing any work if the most interesting FMEM data
7712 have already been populated. */
7721 /* Recursively check the primary base class first. */
7723 {
7726 }
7728 /* Recursively check the base classes. */
7731 {
7734 /* The primary base class was already checked above. */
7738 /* Virtual base classes are at the end. */
7742 /* Check the base class. */
7744 }
7747 {
7748 /* Check virtual base classes only once per derived class.
7749 I.e., this check is not performed recursively for base
7750 classes. */
7752 tree base_binfo;
7756 {
7757 /* Check the virtual base class. */
7761 }
7762 }
7764 /* Is the type unnamed (and therefore a member of it potentially
7765 an anonymous struct or union)? */
7770 /* Search the members of the current (possibly derived) class, skipping
7771 unnamed structs and unions since those could be anonymous. */
7776 {
7777 /* Issue diagnostics for invalid flexible and zero-length array
7778 members found in base classes or among the members of the current
7779 class. Ignore anonymous structs and unions whose members are
7780 considered to be members of the enclosing class and thus will
7781 be diagnosed when checking it. */
7783 }
7784 }
7786 /* Perform processing required when the definition of T (a class type)
7787 is complete. Diagnose invalid definitions of flexible array members
7788 and zero-size arrays. */
7790 void
7792 {
7793 tree x;
7794 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
7798 {
7803 }
7805 /* If this type was previously laid out as a forward reference,
7806 make sure we lay it out again. */
7810 /* Make assumptions about the class; we'll reset the flags if
7811 necessary. */
7817 /* Do end-of-class semantic processing: checking the validity of the
7818 bases and members and add implicitly generated methods. */
7821 /* Find the key method. */
7823 {
7824 /* The Itanium C++ ABI permits the key method to be chosen when
7825 the class is defined -- even though the key method so
7826 selected may later turn out to be an inline function. On
7827 some systems (such as ARM Symbian OS) the key method cannot
7828 be determined until the end of the translation unit. On such
7829 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
7830 will cause the class to be added to KEYED_CLASSES. Then, in
7831 finish_file we will determine the key method. */
7835 /* If a polymorphic class has no key method, we may emit the vtable
7836 in every translation unit where the class definition appears. If
7837 we're devirtualizing, we can look into the vtable even if we
7838 aren't emitting it. */
7841 }
7843 /* Layout the class itself. */
7845 /* COMPLETE_TYPE_P is now true. */
7849 /* With the layout complete, check for flexible array members and
7850 zero-length arrays that might overlap other members in the final
7851 layout. */
7856 /* If necessary, create the primary vtable for this class. */
7858 {
7859 /* We must enter these virtuals into the table. */
7863 /* Here we know enough to change the type of our virtual
7864 function table, but we will wait until later this function. */
7867 /* If we're warning about ABI tags, check the types of the new
7868 virtual functions. */
7872 }
7875 {
7877 tree fn;
7884 /* Add entries for virtual functions introduced by this class. */
7888 /* Set DECL_VINDEX for all functions declared in this class. */
7890 fn;
7892 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
7894 {
7898 /* A thunk. We should never be calling this entry directly
7899 from this vtable -- we'd use the entry for the non
7900 thunk base function. */
7904 }
7905 }
7913 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
7914 for any static member objects of the type we're working on. */
7917 {
7918 /* Synthesize constexpr defaulted comparisons. */
7924 }
7930 /* Complain if one of the field types requires lower visibility. */
7933 /* Make the rtl for any new vtables we have created, and unmark
7934 the base types we marked. */
7937 /* Build the VTT for T. */
7944 "%q#T has virtual functions and accessible"
7952 /* Class layout, assignment of virtual table slots, etc., is now
7953 complete. Give the back end a chance to tweak the visibility of
7954 the class or perform any other required target modifications. */
7964 /* Finish debugging output for this type. */
7968 {
7971 {
7974 }
7976 {
7979 else
7980 {
7983 }
7985 }
7987 {
7989 "the type of the first field has a different ABI from the "
7992 }
7993 }
7994 }
7996 /* When T was built up, the member declarations were added in reverse
7997 order. Rearrange them to declaration order. */
7999 void
8001 {
8002 tree next;
8003 tree prev;
8004 tree x;
8006 /* The following lists are all in reverse order. Put them in
8007 declaration order now. */
8010 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
8011 order, so we can't just use nreverse. Due to stat_hack
8012 chicanery in finish_member_declaration. */
8017 {
8021 }
8024 {
8027 }
8028 }
8030 /* Classes, structs or unions T marked with hotness attributes propagate
8031 the attribute to all methods. */
8033 void
8035 {
8041 tree class_has_cold_attr
8043 tree class_has_hot_attr
8050 }
8052 tree
8054 {
8057 /* Now that we've got all the field declarations, reverse everything
8058 as necessary. */
8064 /* Nadger the current location so that diagnostics point to the start of
8065 the struct, not the end. */
8069 {
8070 tree x;
8074 {
8078 }
8080 {
8083 }
8085 /* Also add a USING_DECL for operator=. We know there'll be (at
8086 least) one, but we don't know the signature(s). We want name
8087 lookup not to fail or recurse into bases. This isn't added
8088 to the template decl list so we drop this at instantiation
8089 time. */
8091 NULL_TREE);
8101 /* COMPLETE_TYPE_P is now true. */
8105 /* We need to emit an error message if this type was used as a parameter
8106 and it is an abstract type, even if it is a template. We construct
8107 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
8108 account and we call complete_vars with this type, which will check
8109 the PARM_DECLS. Note that while the type is being defined,
8110 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
8111 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
8118 /* Remember current #pragma pack value. */
8122 {
8126 }
8130 /* Fix up any variants we've already built. */
8132 }
8133 else
8135 /* COMPLETE_TYPE_P is now true. */
8140 {
8141 /* People keep complaining that the compiler crashes on an invalid
8142 definition of initializer_list, so I guess we should explicitly
8143 reject it. What the compiler internals care about is that it's a
8144 template and has a pointer field followed by size_type field. */
8147 {
8150 {
8154 }
8155 }
8156 /* It also cannot be a union. */
8161 }
8169 else
8181 /* Lambdas are defined by the LAMBDA_EXPR. */
8186 }
8187 \f
8188 /* Hash table to avoid endless recursion when handling references. */
8191 /* Return the dynamic type of INSTANCE, if known.
8192 Used to determine whether the virtual function table is needed
8193 or not.
8195 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
8196 of our knowledge of its type. *NONNULL should be initialized
8197 before this function is called. */
8199 static tree
8201 {
8202 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
8205 {
8209 else
8213 /* This is a call to a constructor, hence it's never zero. */
8216 {
8220 }
8224 /* This is a call to a constructor, hence it's never zero. */
8226 {
8230 }
8239 /* Propagate nonnull. */
8244 CASE_CONVERT:
8250 {
8251 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
8252 with a real object -- given &p->f, p can still be null. */
8254 /* ??? Probably should check DECL_WEAK here. */
8257 }
8261 /* If this component is really a base class reference, then the field
8262 itself isn't definitive. */
8271 {
8275 }
8276 /* fall through. */
8281 {
8285 }
8287 {
8291 /* if we're in a ctor or dtor, we know our type. If
8292 current_class_ptr is set but we aren't in a function, we're in
8293 an NSDMI (and therefore a constructor). */
8298 {
8302 }
8303 }
8305 {
8306 /* We only need one hash table because it is always left empty. */
8308 fixed_type_or_null_ref_ht
8311 /* Reference variables should be references to objects. */
8315 /* Enter the INSTANCE in a table to prevent recursion; a
8316 variable's initializer may refer to the variable
8317 itself. */
8322 {
8323 tree type;
8332 }
8333 }
8339 else
8340 /* TODO: Recursion may be correct for some non-location-wrapper
8341 uses of VIEW_CONVERT_EXPR. */
8346 }
8347 #undef RECUR
8348 }
8350 /* Return nonzero if the dynamic type of INSTANCE is known, and
8351 equivalent to the static type. We also handle the case where
8352 INSTANCE is really a pointer. Return negative if this is a
8353 ctor/dtor. There the dynamic type is known, but this might not be
8354 the most derived base of the original object, and hence virtual
8355 bases may not be laid out according to this type.
8357 Used to determine whether the virtual function table is needed
8358 or not.
8360 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
8361 of our knowledge of its type. *NONNULL should be initialized
8362 before this function is called. */
8364 int
8366 {
8369 tree fixed;
8371 /* processing_template_decl can be false in a template if we're in
8372 instantiate_non_dependent_expr, but we still want to suppress
8373 this check. */
8375 {
8376 /* In a template we only care about the type of the result. */
8380 }
8392 }
8394 \f
8395 void
8397 {
8400 current_class_stack
8407 }
8409 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
8411 static void
8413 {
8414 tree type;
8416 /* We are re-entering the same class we just left, so we don't
8417 have to search the whole inheritance matrix to find all the
8418 decls to bind again. Instead, we install the cached
8419 class_shadowed list and walk through it binding names. */
8422 /* Restore IDENTIFIER_TYPE_VALUE. */
8424 type;
8427 }
8429 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
8430 appropriate for TYPE.
8432 So that we may avoid calls to lookup_name, we cache the _TYPE
8433 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
8435 For multiple inheritance, we perform a two-pass depth-first search
8436 of the type lattice. */
8438 void
8440 {
8441 class_stack_node_t csn;
8445 /* Make sure there is enough room for the new entry on the stack. */
8447 {
8449 current_class_stack
8451 current_class_stack_size);
8452 }
8454 /* Insert a new entry on the class stack. */
8461 current_class_depth++;
8463 /* Now set up the new type. */
8469 /* By default, things in classes are private, while things in
8470 structures or unions are public. */
8472 ? access_private_node
8478 {
8479 /* Forcibly remove any old class remnants. */
8481 }
8487 else
8489 }
8491 /* Get out of the current class scope. If we were in a class scope
8492 previously, that is the one popped to. */
8494 void
8496 {
8499 current_class_depth--;
8505 }
8507 /* Mark the top of the class stack as hidden. */
8509 void
8511 {
8514 }
8516 /* Mark the top of the class stack as un-hidden. */
8518 void
8520 {
8523 }
8525 /* If the class type currently being defined is either T or
8526 a nested type of T, returns the type from the current_class_stack,
8527 which might be equivalent to but not equal to T in case of
8528 constrained partial specializations. */
8530 tree
8532 {
8540 /* We start looking from 1 because entry 0 is from global scope,
8541 and has no type. */
8543 {
8544 tree c;
8547 else
8548 {
8552 }
8557 }
8559 }
8561 /* If either current_class_type or one of its enclosing classes are derived
8562 from T, return the appropriate type. Used to determine how we found
8563 something via unqualified lookup. */
8565 tree
8567 {
8570 /* The bases of a dependent type are unknown. */
8581 {
8586 }
8589 }
8591 /* Return the outermost enclosing class type that is still open, or
8592 NULL_TREE. */
8594 tree
8596 {
8603 {
8610 }
8612 }
8614 /* Returns the innermost class type which is not a lambda closure type. */
8616 tree
8618 {
8623 }
8625 /* When entering a class scope, all enclosing class scopes' names with
8626 static meaning (static variables, static functions, types and
8627 enumerators) have to be visible. This recursive function calls
8628 pushclass for all enclosing class contexts until global or a local
8629 scope is reached. TYPE is the enclosed class. */
8631 void
8633 {
8634 /* A namespace might be passed in error cases, like A::B:C. */
8642 }
8644 /* Undoes a push_nested_class call. */
8646 void
8648 {
8654 }
8656 /* Returns the number of extern "LANG" blocks we are nested within. */
8658 int
8660 {
8662 }
8664 /* Set global variables CURRENT_LANG_NAME to appropriate value
8665 so that behavior of name-mangling machinery is correct. */
8667 void
8669 {
8676 else
8678 }
8680 /* Get out of the current language scope. */
8682 void
8684 {
8686 }
8687 \f
8688 /* Type instantiation routines. */
8690 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
8691 matches the TARGET_TYPE. If there is no satisfactory match, return
8692 error_mark_node, and issue an error & warning messages under
8693 control of FLAGS. Permit pointers to member function if FLAGS
8694 permits. If TEMPLATE_ONLY, the name of the overloaded function was
8695 a template-id, and EXPLICIT_TARGS are the explicitly provided
8696 template arguments.
8698 If OVERLOAD is for one or more member functions, then ACCESS_PATH
8699 is the base path used to reference those member functions. If
8700 the address is resolved to a member function, access checks will be
8701 performed and errors issued if appropriate. */
8703 static tree
8705 tree overload,
8706 tsubst_flags_t complain,
8708 tree explicit_targs,
8709 tree access_path)
8710 {
8711 /* Here's what the standard says:
8713 [over.over]
8715 If the name is a function template, template argument deduction
8716 is done, and if the argument deduction succeeds, the deduced
8717 arguments are used to generate a single template function, which
8718 is added to the set of overloaded functions considered.
8720 Non-member functions and static member functions match targets of
8721 type "pointer-to-function" or "reference-to-function." Nonstatic
8722 member functions match targets of type "pointer-to-member
8723 function;" the function type of the pointer to member is used to
8724 select the member function from the set of overloaded member
8725 functions. If a non-static member function is selected, the
8726 reference to the overloaded function name is required to have the
8727 form of a pointer to member as described in 5.3.1.
8729 If more than one function is selected, any template functions in
8730 the set are eliminated if the set also contains a non-template
8731 function, and any given template function is eliminated if the
8732 set contains a second template function that is more specialized
8733 than the first according to the partial ordering rules 14.5.5.2.
8734 After such eliminations, if any, there shall remain exactly one
8735 selected function. */
8738 /* We store the matches in a TREE_LIST rooted here. The functions
8739 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
8740 interoperability with most_specialized_instantiation. */
8742 tree fn;
8743 tree target_fn_type;
8745 /* By the time we get here, we should be seeing only real
8746 pointer-to-member types, not the internal POINTER_TYPE to
8747 METHOD_TYPE representation. */
8753 /* Check that the TARGET_TYPE is reasonable. */
8758 /* This is OK, too. */
8761 /* This is OK, too. This comes from a conversion to reference
8762 type. */
8764 else
8765 {
8771 }
8773 /* Non-member functions and static member functions match targets of type
8774 "pointer-to-function" or "reference-to-function." Nonstatic member
8775 functions match targets of type "pointer-to-member-function;" the
8776 function type of the pointer to member is used to select the member
8777 function from the set of overloaded member functions.
8779 So figure out the FUNCTION_TYPE that we want to match against. */
8782 /* If we can find a non-template function that matches, we can just
8783 use it. There's no point in generating template instantiations
8784 if we're just going to throw them out anyhow. But, of course, we
8785 can only do this when we don't *need* a template function. */
8788 {
8792 /* We're not looking for templates just yet. */
8796 /* We're looking for a non-static member, and this isn't
8797 one, or vice versa. */
8800 /* Constraints must be satisfied. This is done before
8801 return type deduction since that instantiates the
8802 function. */
8807 {
8808 /* Force instantiation to do return type deduction. */
8811 }
8813 /* In C++17 we need the noexcept-qualifier to compare types. */
8818 /* See if there's a match. */
8823 }
8825 /* Now, if we've already got a match (or matches), there's no need
8826 to proceed to the template functions. But, if we don't have a
8827 match we need to look at them, too. */
8829 {
8830 tree target_arg_types;
8831 tree target_ret_type;
8834 tree arg;
8848 {
8850 tree instantiation;
8851 tree targs;
8854 /* We're only looking for templates. */
8859 /* We're not looking for a non-static member, and this is
8860 one, or vice versa. */
8865 /* If the template has a deduced return type, don't expose it to
8866 template argument deduction. */
8870 /* Try to do argument deduction. */
8877 /* Instantiation failed. */
8880 /* Constraints must be satisfied. This is done before
8881 return type deduction since that instantiates the
8882 function. */
8886 /* And now force instantiation to do return type deduction. */
8888 {
8894 }
8896 /* In C++17 we need the noexcept-qualifier to compare types. */
8900 /* See if there's a match. */
8905 }
8907 /* Now, remove all but the most specialized of the matches. */
8909 {
8914 NULL_TREE,
8915 NULL_TREE);
8916 }
8917 }
8919 /* Now we should have exactly one function in MATCHES. */
8921 {
8922 /* There were *no* matches. */
8924 {
8929 }
8931 }
8933 {
8934 /* There were too many matches. First check if they're all
8935 the same function. */
8940 /* For multi-versioned functions, more than one match is just fine and
8941 decls_match will return false as they are different. */
8949 {
8951 {
8955 /* Since print_candidates expects the functions in the
8956 TREE_VALUE slot, we flip them here. */
8961 }
8964 }
8965 }
8967 /* Good, exactly one match. Now, convert it to the correct type. */
8972 {
8973 /* Previously we allowed this behavior for iobj member functions when the
8974 -fms-extensions flag is passed as MSVC allows this as a language
8975 extension. MSVC also allows this for xobj member functions, but the
8976 documentation for -fms-extensions states it's purpose is to support
8977 the use of microsoft headers. Until otherwise demonstrated, we should
8978 assume xobj member functions are not used in this manner in microsoft
8979 headers and indiscriminately forbid the incorrect syntax instead of
8980 supporting it for non-legacy uses. This should hopefully encourage
8981 conformance going forward.
8982 This comment is referred to in typeck.cc:cp_build_addr_expr_1. */
8988 {
8989 auto_diagnostic_group d;
8990 /* Should match the error in typeck.cc:cp_build_addr_expr_1.
8991 We seem to lack the details here to match that diagnostic exactly,
8992 perhaps this could be fixed in the future? See PR113075 bug 2. */
8994 "ISO C++ forbids taking the address of an unqualified"
8995 " or parenthesized non-static member function to form"
8997 /* This is incorrect, see PR113075 bug 3. */
8999 "a pointer to explicit object member function can only be "
9001 }
9002 else
9003 {
9006 /* Is there a reason this error message doesn't match the one in
9007 typeck.cc:cp_build_addr_expr_1? */
9008 auto_diagnostic_group d;
9011 {
9015 }
9016 }
9017 }
9019 /* If a pointer to a function that is multi-versioned is requested, the
9020 pointer to the dispatcher function is returned instead. This works
9021 well because indirectly calling the function will dispatch the right
9022 function version at run-time. */
9024 {
9028 /* Mark all the versions corresponding to the dispatcher as used. */
9031 }
9033 /* If we're doing overload resolution purely for the purpose of
9034 determining conversion sequences, we should not consider the
9035 function used. If this conversion sequence is selected, the
9036 function will be marked as used at this point. */
9038 {
9039 /* Make =delete work with SFINAE. */
9044 }
9046 /* We could not check access to member functions when this
9047 expression was originally created since we did not know at that
9048 time to which function the expression referred. */
9050 {
9053 }
9057 else
9058 {
9059 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
9060 will mark the function as addressed, but here we must do it
9061 explicitly. */
9065 }
9066 }
9068 /* This function will instantiate the type of the expression given in
9069 RHS to match the type of LHSTYPE. If errors exist, then return
9070 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
9071 we complain on errors. If we are not complaining, never modify rhs,
9072 as overload resolution wants to try many possible instantiations, in
9073 the hope that at least one will work.
9075 For non-recursive calls, LHSTYPE should be a function, pointer to
9076 function, or a pointer to member function. */
9078 tree
9080 {
9089 {
9093 }
9096 {
9105 /* Microsoft allows `A::f' to be resolved to a
9106 pointer-to-member. */
9107 ;
9108 else
9109 {
9114 }
9115 }
9117 /* If we instantiate a template, and it is a A ?: C expression
9118 with omitted B, look through the SAVE_EXPR. */
9123 {
9126 }
9128 /* There are only a few kinds of expressions that may have a type
9129 dependent on overload resolution. */
9135 /* This should really only be used when attempting to distinguish
9136 what sort of a pointer to function we have. For now, any
9137 arithmetic operation which is not supported on pointers
9138 is rejected as an error. */
9141 {
9143 {
9149 /* Do not lose object's side effects. */
9153 }
9160 /* This can happen if we are forming a pointer-to-member for a
9161 member template. */
9164 /* Fall through. */
9167 {
9171 return
9175 }
9179 return
9183 access_path);
9186 {
9191 }
9198 }
9200 }
9201 \f
9202 /* Return the name of the virtual function pointer field
9203 (as an IDENTIFIER_NODE) for the given TYPE. Note that
9204 this may have to look back through base types to find the
9205 ultimate field name. (For single inheritance, these could
9206 all be the same name. Who knows for multiple inheritance). */
9208 static tree
9210 {
9216 {
9222 }
9230 }
9232 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
9233 according to [class]:
9234 The class-name is also inserted
9235 into the scope of the class itself. For purposes of access checking,
9236 the inserted class name is treated as if it were a public member name. */
9238 void
9240 {
9258 }
9260 /* Returns 1 if TYPE contains only padding bytes. */
9262 int
9264 {
9272 }
9274 /* Returns true if TYPE contains no actual data, just various
9275 possible combinations of empty classes. If IGNORE_VPTR is true,
9276 a vptr doesn't prevent the class from being considered empty. Typically
9277 we want to ignore the vptr on assignment, and not on initialization. */
9279 bool
9281 {
9283 {
9284 tree field;
9285 tree binfo;
9286 tree base_binfo;
9289 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
9290 out, but we'd like to be able to check this before then. */
9304 /* An unnamed bit-field is not a data member. */
9309 }
9314 }
9316 /* Note that NAME was looked up while the current class was being
9317 defined and that the result of that lookup was DECL. */
9319 void
9321 {
9322 /* If we're not defining a class, there's nothing to do. */
9333 /* Record the binding in the names_used tables for classes inside blev. */
9335 {
9337 ? current_class_type
9341 {
9343 /* We found the declaration. */
9346 /* This class is inside the declaration scope. */
9348 }
9360 }
9361 }
9363 /* Note that NAME was declared (as DECL) in the current class. Check
9364 to see that the declaration is valid under [class.member.lookup]:
9366 If [the result of a search in T for N at point P] differs from the result of
9367 a search in T for N from immediately after the class-specifier of T, the
9368 program is ill-formed, no diagnostic required. */
9370 void
9372 {
9373 splay_tree names_used;
9374 splay_tree_node n;
9376 /* Look to see if we ever used this name. */
9377 names_used
9381 /* The C language allows members to be declared with a type of the same
9382 name, and the C++ standard says this diagnostic is not required. So
9383 allow it in extern "C" blocks unless pedantic is specified.
9384 Allow it in all cases if -ms-extensions is specified. */
9390 {
9394 /* [basic.scope.class]
9396 A name N used in a class S shall refer to the same declaration
9397 in its context and when re-evaluated in the completed scope of
9398 S. */
9406 else
9407 /* Make it an error. */
9412 {
9415 }
9416 }
9417 }
9419 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
9420 Secondary vtables are merged with primary vtables; this function
9421 will return the VAR_DECL for the primary vtable. */
9423 tree
9425 {
9426 tree decl;
9430 {
9433 }
9437 }
9440 /* Returns the binfo for the primary base of BINFO. If the resulting
9441 BINFO is a virtual base, and it is inherited elsewhere in the
9442 hierarchy, then the returned binfo might not be the primary base of
9443 BINFO in the complete object. Check BINFO_PRIMARY_P or
9444 BINFO_LOST_PRIMARY_P to be sure. */
9446 static tree
9448 {
9449 tree primary_base;
9456 }
9458 /* As above, but iterate until we reach the binfo that actually provides the
9459 vptr for BINFO. */
9461 static tree
9463 {
9467 {
9472 }
9474 }
9476 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
9477 type. Note that the virtual inheritance might be above or below BINFO in
9478 the hierarchy. */
9480 bool
9482 {
9486 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
9487 a morally virtual base. */
9490 }
9492 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
9494 static int
9496 {
9500 }
9502 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
9503 INDENT should be zero when called from the top level; it is
9504 incremented recursively. IGO indicates the next expected BINFO in
9505 inheritance graph ordering. */
9507 static tree
9509 dump_flags_t flags,
9510 tree binfo,
9511 tree igo,
9513 {
9515 tree base_binfo;
9522 {
9525 }
9539 {
9543 TFF_PLAIN_IDENTIFIER),
9545 }
9547 {
9550 }
9555 {
9559 {
9563 TFF_PLAIN_IDENTIFIER));
9564 }
9566 {
9570 TFF_PLAIN_IDENTIFIER));
9571 }
9573 {
9577 TFF_PLAIN_IDENTIFIER));
9578 }
9580 {
9584 TFF_PLAIN_IDENTIFIER));
9585 }
9589 }
9595 }
9597 /* Dump the BINFO hierarchy for T. */
9599 static void
9601 {
9613 }
9615 /* Debug interface to hierarchy dumping. */
9617 void
9619 {
9621 }
9623 static void
9625 {
9626 dump_flags_t flags;
9628 {
9631 }
9632 }
9634 static void
9636 {
9637 tree value;
9639 HOST_WIDE_INT elt;
9647 TFF_PLAIN_IDENTIFIER));
9654 }
9656 static void
9658 {
9659 dump_flags_t flags;
9666 {
9673 {
9678 }
9682 }
9685 }
9687 static void
9689 {
9690 dump_flags_t flags;
9697 {
9702 }
9705 }
9707 /* Dump a function or thunk and its thunkees. */
9709 static void
9711 {
9714 tree thunks;
9722 {
9732 else
9738 }
9742 }
9744 /* Dump the thunks for FN. */
9746 void
9748 {
9750 }
9752 /* Virtual function table initialization. */
9754 /* Create all the necessary vtables for T and its base classes. */
9756 static void
9758 {
9759 tree vbase;
9763 /* We lay out the primary and secondary vtables in one contiguous
9764 vtable. The primary vtable is first, followed by the non-virtual
9765 secondary vtables in inheritance graph order. */
9769 /* Then come the virtual bases, also in inheritance graph order. */
9771 {
9775 }
9779 }
9781 /* Initialize the vtable for BINFO with the INITS. */
9783 static void
9785 {
9786 tree decl;
9792 }
9794 /* Build the VTT (virtual table table) for T.
9795 A class requires a VTT if it has virtual bases.
9797 This holds
9798 1 - primary virtual pointer for complete object T
9799 2 - secondary VTTs for each direct non-virtual base of T which requires a
9800 VTT
9801 3 - secondary virtual pointers for each direct or indirect base of T which
9802 has virtual bases or is reachable via a virtual path from T.
9803 4 - secondary VTTs for each direct or indirect virtual base of T.
9805 Secondary VTTs look like complete object VTTs without part 4. */
9807 static void
9809 {
9810 tree type;
9811 tree vtt;
9812 tree index;
9815 /* Build up the initializers for the VTT. */
9820 /* If we didn't need a VTT, we're done. */
9824 /* Figure out the type of the VTT. */
9828 /* Now, build the VTT object itself. */
9831 /* Add the VTT to the vtables list. */
9836 }
9838 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
9839 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
9840 and CHAIN the vtable pointer for this binfo after construction is
9841 complete. VALUE can also be another BINFO, in which case we recurse. */
9843 static tree
9845 {
9846 tree vt;
9849 {
9855 else
9857 }
9860 }
9862 /* Data for secondary VTT initialization. */
9863 struct secondary_vptr_vtt_init_data
9864 {
9865 /* Is this the primary VTT? */
9868 /* Current index into the VTT. */
9869 tree index;
9871 /* Vector of initializers built up. */
9874 /* The type being constructed by this secondary VTT. */
9875 tree type_being_constructed;
9876 };
9878 /* Recursively build the VTT-initializer for BINFO (which is in the
9879 hierarchy dominated by T). INITS points to the end of the initializer
9880 list to date. INDEX is the VTT index where the next element will be
9881 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
9882 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
9883 for virtual bases of T. When it is not so, we build the constructor
9884 vtables for the BINFO-in-T variant. */
9886 static void
9889 {
9891 tree b;
9892 tree init;
9893 secondary_vptr_vtt_init_data data;
9896 /* We only need VTTs for subobjects with virtual bases. */
9900 /* We need to use a construction vtable if this is not the primary
9901 VTT. */
9903 {
9906 /* Record the offset in the VTT where this sub-VTT can be found. */
9908 }
9910 /* Add the address of the primary vtable for the complete object. */
9914 {
9917 }
9920 /* Recursively add the secondary VTTs for non-virtual bases. */
9925 /* Add secondary virtual pointers for all subobjects of BINFO with
9926 either virtual bases or reachable along a virtual path, except
9927 subobjects that are non-virtual primary bases. */
9937 /* data.inits might have grown as we added secondary virtual pointers.
9938 Make sure our caller knows about the new vector. */
9942 /* Add the secondary VTTs for virtual bases in inheritance graph
9943 order. */
9945 {
9950 }
9951 else
9952 /* Remove the ctor vtables we created. */
9954 }
9956 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
9957 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
9959 static tree
9961 {
9964 /* We don't care about bases that don't have vtables. */
9968 /* We're only interested in proper subobjects of the type being
9969 constructed. */
9973 /* We're only interested in bases with virtual bases or reachable
9974 via a virtual path from the type being constructed. */
9979 /* We're not interested in non-virtual primary bases. */
9983 /* Record the index where this secondary vptr can be found. */
9985 {
9990 {
9991 /* It's a primary virtual base, and this is not a
9992 construction vtable. Find the base this is primary of in
9993 the inheritance graph, and use that base's vtable
9994 now. */
9997 }
9998 }
10000 /* Add the initializer for the secondary vptr itself. */
10003 /* Advance the vtt index. */
10008 }
10010 /* Called from build_vtt_inits via dfs_walk. After building
10011 constructor vtables and generating the sub-vtt from them, we need
10012 to restore the BINFO_VTABLES that were scribbled on. DATA is the
10013 binfo of the base whose sub vtt was generated. */
10015 static tree
10017 {
10021 /* If this class has no vtable, none of its bases do. */
10025 /* This might be a primary base, so have no vtable in this
10026 hierarchy. */
10029 /* If we scribbled the construction vtable vptr into BINFO, clear it
10030 out now. */
10036 }
10038 /* Build the construction vtable group for BINFO which is in the
10039 hierarchy dominated by T. */
10041 static void
10043 {
10044 tree type;
10045 tree vtbl;
10046 tree id;
10047 tree vbase;
10050 /* See if we've already created this construction vtable group. */
10056 /* Build a version of VTBL (with the wrong type) for use in
10057 constructing the addresses of secondary vtables in the
10058 construction vtable group. */
10061 /* Don't export construction vtables from shared libraries. Even on
10062 targets that don't support hidden visibility, this tells
10063 can_refer_decl_in_current_unit_p not to assume that it's safe to
10064 access from a different compilation unit (bz 54314). */
10072 /* Add the vtables for each of our virtual bases using the vbase in T
10073 binfo. */
10075 vbase;
10077 {
10078 tree b;
10085 }
10087 /* Figure out the type of the construction vtable. */
10094 /* Initialize the construction vtable. */
10098 }
10100 /* Add the vtbl initializers for BINFO (and its bases other than
10101 non-virtual primaries) to the list of INITS. BINFO is in the
10102 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
10103 the constructor the vtbl inits should be accumulated for. (If this
10104 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
10105 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
10106 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
10107 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
10108 but are not necessarily the same in terms of layout. */
10110 static void
10112 tree orig_binfo,
10113 tree rtti_binfo,
10114 tree vtbl,
10115 tree t,
10117 {
10119 tree base_binfo;
10124 /* If it doesn't have a vptr, we don't do anything. */
10128 /* If we're building a construction vtable, we're not interested in
10129 subobjects that don't require construction vtables. */
10135 /* Build the initializers for the BINFO-in-T vtable. */
10138 /* Walk the BINFO and its bases. We walk in preorder so that as we
10139 initialize each vtable we can figure out at what offset the
10140 secondary vtable lies from the primary vtable. We can't use
10141 dfs_walk here because we need to iterate through bases of BINFO
10142 and RTTI_BINFO simultaneously. */
10144 {
10145 /* Skip virtual bases. */
10151 inits);
10152 }
10153 }
10155 /* Called from accumulate_vtbl_inits. Adds the initializers for the
10156 BINFO vtable to L. */
10158 static void
10160 tree orig_binfo,
10161 tree rtti_binfo,
10162 tree orig_vtbl,
10163 tree t,
10165 {
10172 {
10173 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
10174 primary virtual base. If it is not the same primary in
10175 the hierarchy of T, we'll need to generate a ctor vtable
10176 for it, to place at its location in T. If it is the same
10177 primary, we still need a VTT entry for the vtable, but it
10178 should point to the ctor vtable for the base it is a
10179 primary for within the sub-hierarchy of RTTI_BINFO.
10181 There are three possible cases:
10183 1) We are in the same place.
10184 2) We are a primary base within a lost primary virtual base of
10185 RTTI_BINFO.
10186 3) We are primary to something not a base of RTTI_BINFO. */
10188 tree b;
10191 /* First, look through the bases we are primary to for RTTI_BINFO
10192 or a virtual base. */
10195 {
10200 }
10201 /* If we run out of primary links, keep looking down our
10202 inheritance chain; we might be an indirect primary. */
10206 found:
10208 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
10209 base B and it is a base of RTTI_BINFO, this is case 2. In
10210 either case, we share our vtable with LAST, i.e. the
10211 derived-most base within B of which we are a primary. */
10214 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
10215 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
10216 binfo_ctor_vtable after everything's been set up. */
10219 /* Otherwise, this is case 3 and we get our own. */
10220 }
10227 {
10228 tree index;
10231 /* Add the initializer for this vtable. */
10235 /* Figure out the position to which the VPTR should point. */
10241 }
10244 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
10245 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
10246 straighten this out. */
10249 /* Throw away any unneeded intializers. */
10251 else
10252 /* For an ordinary vtable, set BINFO_VTABLE. */
10254 }
10259 /* Construct the initializer for BINFO's virtual function table. BINFO
10260 is part of the hierarchy dominated by T. If we're building a
10261 construction vtable, the ORIG_BINFO is the binfo we should use to
10262 find the actual function pointers to put in the vtable - but they
10263 can be overridden on the path to most-derived in the graph that
10264 ORIG_BINFO belongs. Otherwise,
10265 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
10266 BINFO that should be indicated by the RTTI information in the
10267 vtable; it will be a base class of T, rather than T itself, if we
10268 are building a construction vtable.
10270 The value returned is a TREE_LIST suitable for wrapping in a
10271 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
10272 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
10273 number of non-function entries in the vtable.
10275 It might seem that this function should never be called with a
10276 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
10277 base is always subsumed by a derived class vtable. However, when
10278 we are building construction vtables, we do build vtables for
10279 primary bases; we need these while the primary base is being
10280 constructed. */
10282 static void
10284 tree orig_binfo,
10285 tree t,
10286 tree rtti_binfo,
10289 {
10290 tree v;
10291 vtbl_init_data vid;
10293 tree vbinfo;
10297 /* Initialize VID. */
10305 /* The first vbase or vcall offset is at index -3 in the vtable. */
10308 /* Add entries to the vtable for RTTI. */
10311 /* Create an array for keeping track of the functions we've
10312 processed. When we see multiple functions with the same
10313 signature, we share the vcall offsets. */
10315 /* Add the vcall and vbase offset entries. */
10318 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
10319 build_vbase_offset_vtbl_entries. */
10324 /* If the target requires padding between data entries, add that now. */
10326 {
10332 /* Move data entries into their new positions and add padding
10333 after the new positions. Iterate backwards so we don't
10334 overwrite entries that we would need to process later. */
10337 ix--)
10338 {
10346 {
10350 null_pointer_node);
10351 }
10352 }
10353 }
10358 /* The initializers for virtual functions were built up in reverse
10359 order. Straighten them out and add them to the running list in one
10360 step. */
10369 /* Go through all the ordinary virtual functions, building up
10370 initializers. */
10372 {
10373 tree delta;
10374 tree vcall_index;
10381 {
10385 {
10388 }
10390 }
10392 /* If the only definition of this function signature along our
10393 primary base chain is from a lost primary, this vtable slot will
10394 never be used, so just zero it out. This is important to avoid
10395 requiring extra thunks which cannot be generated with the function.
10397 We first check this in update_vtable_entry_for_fn, so we handle
10398 restored primary bases properly; we also need to do it here so we
10399 zero out unused slots in ctor vtables, rather than filling them
10400 with erroneous values (though harmless, apart from relocation
10401 costs). */
10406 {
10407 /* Pull the offset for `this', and the function to call, out of
10408 the list. */
10415 /* You can't call an abstract virtual function; it's abstract.
10416 So, we replace these functions with __pure_virtual. */
10418 {
10421 {
10423 abort_fndecl_addr
10427 }
10428 }
10429 /* Likewise for deleted virtuals. */
10431 {
10433 {
10437 dvirt_fn = push_library_fn
10441 }
10446 }
10447 else
10448 {
10450 {
10455 }
10456 /* Take the address of the function, considering it to be of an
10457 appropriate generic type. */
10461 /* Don't refer to a virtual destructor from a constructor
10462 vtable or a vtable for an abstract class, since destroying
10463 an object under construction is undefined behavior and we
10464 don't want it to be considered a candidate for speculative
10465 devirtualization. But do create the thunk for ABI
10466 compliance. */
10471 }
10472 }
10474 /* And add it to the chain of initializers. */
10476 {
10481 else
10483 {
10489 }
10490 }
10491 else
10493 }
10494 }
10496 /* Adds to vid->inits the initializers for the vbase and vcall
10497 offsets in BINFO, which is in the hierarchy dominated by T. */
10499 static void
10501 {
10502 tree b;
10504 /* If this is a derived class, we must first create entries
10505 corresponding to the primary base class. */
10510 /* Add the vbase entries for this base. */
10512 /* Add the vcall entries for this base. */
10514 }
10516 /* Returns the initializers for the vbase offset entries in the vtable
10517 for BINFO (which is part of the class hierarchy dominated by T), in
10518 reverse order. VBASE_OFFSET_INDEX gives the vtable index
10519 where the next vbase offset will go. */
10521 static void
10523 {
10524 tree vbase;
10525 tree t;
10526 tree non_primary_binfo;
10528 /* If there are no virtual baseclasses, then there is nothing to
10529 do. */
10535 /* We might be a primary base class. Go up the inheritance hierarchy
10536 until we find the most derived class of which we are a primary base:
10537 it is the offset of that which we need to use. */
10540 {
10541 tree b;
10543 /* If we have reached a virtual base, then it must be a primary
10544 base (possibly multi-level) of vid->binfo, or we wouldn't
10545 have called build_vcall_and_vbase_vtbl_entries for it. But it
10546 might be a lost primary, so just skip down to vid->binfo. */
10548 {
10551 }
10557 }
10559 /* Go through the virtual bases, adding the offsets. */
10561 vbase;
10563 {
10564 tree b;
10565 tree delta;
10570 /* Find the instance of this virtual base in the complete
10571 object. */
10574 /* If we've already got an offset for this virtual base, we
10575 don't need another one. */
10580 /* Figure out where we can find this vbase offset. */
10589 /* The vbase offset had better be the same. */
10592 /* The next vbase will come at a more negative offset. */
10596 /* The initializer is the delta from BINFO to this virtual base.
10597 The vbase offsets go in reverse inheritance-graph order, and
10598 we are walking in inheritance graph order so these end up in
10599 the right order. */
10606 }
10607 }
10609 /* Adds the initializers for the vcall offset entries in the vtable
10610 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
10611 to VID->INITS. */
10613 static void
10615 {
10616 /* We only need these entries if this base is a virtual base. We
10617 compute the indices -- but do not add to the vtable -- when
10618 building the main vtable for a class. */
10621 /* If BINFO is RTTI_BINFO, then (since BINFO does not
10622 correspond to VID->DERIVED), we are building a primary
10623 construction virtual table. Since this is a primary
10624 virtual table, we do not need the vcall offsets for
10625 BINFO. */
10627 {
10628 /* We need a vcall offset for each of the virtual functions in this
10629 vtable. For example:
10631 class A { virtual void f (); };
10632 class B1 : virtual public A { virtual void f (); };
10633 class B2 : virtual public A { virtual void f (); };
10634 class C: public B1, public B2 { virtual void f (); };
10636 A C object has a primary base of B1, which has a primary base of A. A
10637 C also has a secondary base of B2, which no longer has a primary base
10638 of A. So the B2-in-C construction vtable needs a secondary vtable for
10639 A, which will adjust the A* to a B2* to call f. We have no way of
10640 knowing what (or even whether) this offset will be when we define B2,
10641 so we store this "vcall offset" in the A sub-vtable and look it up in
10642 a "virtual thunk" for B2::f.
10644 We need entries for all the functions in our primary vtable and
10645 in our non-virtual bases' secondary vtables. */
10647 /* If we are just computing the vcall indices -- but do not need
10648 the actual entries -- not that. */
10651 /* Now, walk through the non-virtual bases, adding vcall offsets. */
10653 }
10654 }
10656 /* Build vcall offsets, starting with those for BINFO. */
10658 static void
10660 {
10662 tree primary_binfo;
10663 tree base_binfo;
10665 /* Don't walk into virtual bases -- except, of course, for the
10666 virtual base for which we are building vcall offsets. Any
10667 primary virtual base will have already had its offsets generated
10668 through the recursion in build_vcall_and_vbase_vtbl_entries. */
10672 /* If BINFO has a primary base, process it first. */
10677 /* Add BINFO itself to the list. */
10680 /* Scan the non-primary bases of BINFO. */
10684 }
10686 /* Called from build_vcall_offset_vtbl_entries_r. */
10688 static void
10690 {
10691 /* Make entries for the rest of the virtuals. */
10692 tree orig_fn;
10694 /* The ABI requires that the methods be processed in declaration
10695 order. */
10697 orig_fn;
10701 }
10703 /* Add a vcall offset entry for ORIG_FN to the vtable. */
10705 static void
10707 {
10709 tree vcall_offset;
10710 tree derived_entry;
10712 /* If there is already an entry for a function with the same
10713 signature as FN, then we do not need a second vcall offset.
10714 Check the list of functions already present in the derived
10715 class vtable. */
10717 {
10719 /* We only use one vcall offset for virtual destructors,
10720 even though there are two virtual table entries. */
10724 }
10726 /* If we are building these vcall offsets as part of building
10727 the vtable for the most derived class, remember the vcall
10728 offset. */
10730 {
10733 }
10735 /* The next vcall offset will be found at a more negative
10736 offset. */
10740 /* Keep track of this function. */
10744 {
10745 tree base;
10746 tree fn;
10748 /* Find the overriding function. */
10752 else
10753 {
10756 /* The vbase we're working on is a primary base of
10757 vid->binfo. But it might be a lost primary, so its
10758 BINFO_OFFSET might be wrong, so we just use the
10759 BINFO_OFFSET from vid->binfo. */
10765 vcall_offset);
10766 }
10767 /* Add the initializer to the vtable. */
10769 }
10770 }
10772 /* Return vtbl initializers for the RTTI entries corresponding to the
10773 BINFO's vtable. The RTTI entries should indicate the object given
10774 by VID->rtti_binfo. */
10776 static void
10778 {
10779 tree b;
10780 tree t;
10781 tree offset;
10782 tree decl;
10783 tree init;
10787 /* To find the complete object, we will first convert to our most
10788 primary base, and then add the offset in the vtbl to that value. */
10793 /* The second entry is the address of the typeinfo object. */
10796 else
10799 /* Convert the declaration to a type that can be stored in the
10800 vtable. */
10804 /* Add the offset-to-top entry. It comes earlier in the vtable than
10805 the typeinfo entry. Convert the offset to look like a
10806 function pointer, so that we can put it in the vtable. */
10809 }
10811 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
10812 accessibility. */
10814 bool
10816 {
10819 }
10821 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
10823 bool
10825 {
10829 }
10831 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
10832 class between them, if any. */
10834 tree
10836 {
10848 {
10851 }
10855 }