| blob | 8c39bb4a76b1a3edfc01963a89a6e2b8d0e73c8e |
1 /* Functions related to building -*- C++ -*- classes and their related objects.
2 Copyright (C) 1987-2024 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
22 /* High-level class interface. */
41 /* Id for dumping the class hierarchy. */
44 /* The number of nested classes being processed. If we are not in the
45 scope of any class, this is zero. */
49 /* In order to deal with nested classes, we keep a stack of classes.
50 The topmost entry is the innermost class, and is the entry at index
51 CURRENT_CLASS_DEPTH */
54 /* The name of the class. */
55 tree name;
57 /* The _TYPE node for the class. */
58 tree type;
60 /* The access specifier pending for new declarations in the scope of
61 this class. */
62 tree access;
64 /* If were defining TYPE, the names used in this class. */
65 splay_tree names_used;
67 /* Nonzero if this class is no longer open, because of a call to
68 push_to_top_level. */
72 struct vtbl_init_data
73 {
74 /* The base for which we're building initializers. */
75 tree binfo;
76 /* The type of the most-derived type. */
77 tree derived;
78 /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
79 unless ctor_vtbl_p is true. */
80 tree rtti_binfo;
81 /* The negative-index vtable initializers built up so far. These
82 are in order from least negative index to most negative index. */
84 /* The binfo for the virtual base for which we're building
85 vcall offset initializers. */
86 tree vbase;
87 /* The functions in vbase for which we have already provided vcall
88 offsets. */
90 /* The vtable index of the next vcall or vbase offset. */
91 tree index;
92 /* Nonzero if we are building the initializer for the primary
93 vtable. */
95 /* Nonzero if we are building the initializer for a construction
96 vtable. */
98 /* True when adding vcall offset entries to the vtable. False when
99 merely computing the indices. */
101 };
103 /* The type of a function passed to walk_subobject_offsets. */
106 /* The stack itself. This is a dynamically resized array. The
107 number of elements allocated is CURRENT_CLASS_STACK_SIZE. */
111 /* The size of the largest empty class seen in this translation unit. */
141 /* Used by find_flexarrays and related functions. */
189 tree *);
198 splay_tree_key k2);
210 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
212 void
214 {
219 else
221 }
223 /* Return a COND_EXPR that executes TRUE_STMT if this execution of the
224 'structor is in charge of 'structing virtual bases, or FALSE_STMT
225 otherwise. */
227 tree
229 {
239 }
241 /* Convert to or from a base subobject. EXPR is an expression of type
242 `A' or `A*', an expression of type `B' or `B*' is returned. To
243 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
244 the B base instance within A. To convert base A to derived B, CODE
245 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
246 In this latter case, A must not be a morally virtual base of B.
247 NONNULL is true if EXPR is known to be non-NULL (this is only
248 needed when EXPR is of pointer type). CV qualifiers are preserved
249 from EXPR. */
251 tree
253 tree expr,
254 tree binfo,
256 tsubst_flags_t complain)
257 {
260 tree probe;
261 tree offset;
262 tree target_type;
264 tree ptr_target_type;
275 {
281 }
292 {
293 /* This can happen when adjust_result_of_qualified_name_lookup can't
294 find a unique base binfo in a call to a member function. We
295 couldn't give the diagnostic then since we might have been calling
296 a static member function, so we do it now. In other cases, eg.
297 during error recovery (c++/71979), we may not have a base at all. */
299 {
303 }
305 }
312 /* Nothing to do. */
316 {
318 {
320 {
323 "pointer to derived class %qT because the base is "
325 else
329 }
330 else
331 {
337 else
341 }
342 }
344 }
347 || processing_template_decl
350 /* For a non-pointer simple base reference, express it as a COMPONENT_REF
351 without taking its address (and so causing lambda capture, 91933). */
356 {
358 /* This must happen before the call to save_expr. */
360 }
361 else
367 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
368 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
369 expression returned matches the input. */
370 target_type = cp_build_qualified_type
374 /* Do we need to look in the vtable for the real offset? */
377 /* Don't bother with the calculations inside sizeof; they'll ICE if the
378 source type is incomplete and the pointer value doesn't matter. In a
379 template (even in instantiate_non_dependent_expr), we don't have vtables
380 set up properly yet, and the value doesn't matter there either; we're
381 just interested in the result of overload resolution. */
383 {
386 }
389 {
395 }
397 /* If we're in an NSDMI, we don't have the full constructor context yet
398 that we need for converting to a virtual base, so just build a stub
399 CONVERT_EXPR and expand it later in bot_replace. */
402 {
406 }
408 /* Do we need to check for a null pointer? */
410 {
411 /* If we know the conversion will not actually change the value
412 of EXPR, then we can avoid testing the expression for NULL.
413 We have to avoid generating a COMPONENT_REF for a base class
414 field, because other parts of the compiler know that such
415 expressions are always non-NULL. */
419 }
421 /* Protect against multiple evaluation if necessary. */
425 /* Store EXPR and build the real null test just before returning. */
429 /* If this is a simple base reference, express it as a COMPONENT_REF. */
431 /* We don't build base fields for empty bases, and they aren't very
432 interesting to the optimizers anyway. */
434 {
443 }
446 {
447 /* Going via virtual base V_BINFO. We need the static offset
448 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
449 V_BINFO. That offset is an entry in D_BINFO's vtable. */
450 tree v_offset;
453 {
454 /* In a base member initializer, we cannot rely on the
455 vtable being set up. We have to indirect via the
456 vtt_parm. */
457 tree t;
463 }
464 else
465 {
469 {
474 }
477 }
485 v_offset);
497 /* Negative fixed_type_p means this is a constructor or destructor;
498 virtual base layout is fixed in in-charge [cd]tors, but not in
499 base [cd]tors. */
500 offset = build_if_in_charge
502 v_offset);
503 else
505 }
511 {
516 }
517 else
522 indout:
524 {
528 }
530 out:
532 /* Wrap EXPR in a null test. */
536 }
538 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
539 Perform a derived-to-base conversion by recursively building up a
540 sequence of COMPONENT_REFs to the appropriate base fields. */
542 static tree
544 {
547 tree field;
550 {
551 tree temp;
555 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
556 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
557 an lvalue in the front end; only _DECLs and _REFs are lvalues
558 in the back end. */
564 }
566 /* Recurse. */
571 /* Is this the base field created by build_base_field? */
575 /* If we're looking for a field in the most-derived class,
576 also check the field offset; we can have two base fields
577 of the same type if one is an indirect virtual base and one
578 is a direct non-virtual base. */
582 {
583 /* We don't use build_class_member_access_expr here, as that
584 has unnecessary checks, and more importantly results in
585 recursive calls to dfs_walk_once. */
591 /* Mark the expression const or volatile, as appropriate.
592 Even though we've dealt with the type above, we still have
593 to mark the expression itself. */
600 }
602 /* Didn't find the base field?!? */
604 }
606 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
607 type is a class type or a pointer to a class type. In the former
608 case, TYPE is also a class type; in the latter it is another
609 pointer type. If CHECK_ACCESS is true, an error message is emitted
610 if TYPE is inaccessible. If OBJECT has pointer type, the value is
611 assumed to be non-NULL. */
613 tree
615 tsubst_flags_t complain)
616 {
617 tree binfo;
618 tree object_type;
621 {
624 }
625 else
634 }
636 /* EXPR is an expression with unqualified class type. BASE is a base
637 binfo of that class type. Returns EXPR, converted to the BASE
638 type. This function assumes that EXPR is the most derived class;
639 therefore virtual bases can be found at their static offsets. */
641 tree
643 {
644 tree expr_type;
648 {
649 /* If this is a non-empty base, use a COMPONENT_REF. */
653 /* We use fold_build2 and fold_convert below to simplify the trees
654 provided to the optimizers. It is not safe to call these functions
655 when processing a template because they do not handle C++-specific
656 trees. */
664 }
667 }
669 /* True IFF EXPR is a reference to an empty base class "subobject", as built in
670 convert_to_base_statically. We look for the result of the fold_convert
671 call, a NOP_EXPR from one pointer type to another, where the target is an
672 empty base of the original type. */
674 bool
676 {
695 }
696 \f
697 tree
699 {
703 /* Can happen in case of duplicate base types (c++/59082). */
707 /* First, convert to the requested type. */
712 /* Second, the requested type may not be the owner of its own vptr.
713 If not, convert to the base class that owns it. We cannot use
714 convert_to_base here, because VCONTEXT may appear more than once
715 in the inheritance hierarchy of TYPE, and thus direct conversion
716 between the types may be ambiguous. Following the path back up
717 one step at a time via primary bases avoids the problem. */
721 {
724 }
727 }
729 /* Given an object INSTANCE, return an expression which yields the
730 vtable element corresponding to INDEX. There are many special
731 cases for INSTANCE which we take care of here, mainly to avoid
732 creating extra tree nodes when we don't have to. */
734 tree
736 {
737 tree aref;
740 /* Try to figure out what a reference refers to, and
741 access its virtual function table directly. */
749 {
754 }
763 }
765 /* Given a stable object pointer INSTANCE_PTR, return an expression which
766 yields a function pointer corresponding to vtable element INDEX. */
768 tree
770 {
771 tree aref;
775 /* When using function descriptors, the address of the
776 vtable entry is treated as a function pointer. */
781 /* Remember this as a method reference, for later devirtualization. */
786 }
788 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
789 for the given TYPE. */
791 static tree
793 {
795 }
797 /* DECL is an entity associated with TYPE, like a virtual table or an
798 implicitly generated constructor. Determine whether or not DECL
799 should have external or internal linkage at the object file
800 level. This routine does not deal with COMDAT linkage and other
801 similar complexities; it simply sets TREE_PUBLIC if it possible for
802 entities in other translation units to contain copies of DECL, in
803 the abstract. */
805 void
807 {
810 }
812 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
813 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
814 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
816 static tree
818 {
819 tree decl;
822 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
823 now to avoid confusion in mangle_decl. */
834 /* The vtable has not been defined -- yet. */
838 /* Mark the VAR_DECL node representing the vtable itself as a
839 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
840 is rather important that such things be ignored because any
841 effort to actually generate DWARF for them will run into
842 trouble when/if we encounter code like:
844 #pragma interface
845 struct S { virtual void member (); };
847 because the artificial declaration of the vtable itself (as
848 manufactured by the g++ front end) will say that the vtable is
849 a static member of `S' but only *after* the debug output for
850 the definition of `S' has already been output. This causes
851 grief because the DWARF entry for the definition of the vtable
852 will try to refer back to an earlier *declaration* of the
853 vtable as a static member of `S' and there won't be one. We
854 might be able to arrange to have the "vtable static member"
855 attached to the member list for `S' before the debug info for
856 `S' get written (which would solve the problem) but that would
857 require more intrusive changes to the g++ front end. */
861 }
863 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
864 or even complete. If this does not exist, create it. If COMPLETE is
865 nonzero, then complete the definition of it -- that will render it
866 impossible to actually build the vtable, but is useful to get at those
867 which are known to exist in the runtime. */
869 tree
871 {
872 tree decl;
881 {
884 }
887 }
889 /* Build the primary virtual function table for TYPE. If BINFO is
890 non-NULL, build the vtable starting with the initial approximation
891 that it is the same as the one which is the head of the association
892 list. Returns a nonzero value if a new vtable is actually
893 created. */
895 static int
897 {
898 tree decl;
899 tree virtuals;
904 {
906 /* We have already created a vtable for this base, so there's
907 no need to do it again. */
914 }
915 else
916 {
919 }
921 /* Initialize the association list for this type, based
922 on our first approximation. */
927 }
929 /* Give BINFO a new virtual function table which is initialized
930 with a skeleton-copy of its original initialization. The only
931 entry that changes is the `delta' entry, so we can really
932 share a lot of structure.
934 FOR_TYPE is the most derived type which caused this table to
935 be needed.
937 Returns nonzero if we haven't met BINFO before.
939 The order in which vtables are built (by calling this function) for
940 an object must remain the same, otherwise a binary incompatibility
941 can result. */
943 static int
945 {
947 /* We already created a vtable for this base. There's no need to
948 do it again. */
951 /* Remember that we've created a vtable for this BINFO, so that we
952 don't try to do so again. */
955 /* Make fresh virtual list, so we can smash it later. */
958 /* Secondary vtables are laid out as part of the same structure as
959 the primary vtable. */
962 }
964 /* Create a new vtable for BINFO which is the hierarchy dominated by
965 T. Return nonzero if we actually created a new vtable. */
967 static int
969 {
971 /* In this case, it is *type*'s vtable we are modifying. We start
972 with the approximation that its vtable is that of the
973 immediate base class. */
975 else
976 /* This is our very own copy of `basetype' to play with. Later,
977 we will fill in all the virtual functions that override the
978 virtual functions in these base classes which are not defined
979 by the current type. */
981 }
983 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
984 (which is in the hierarchy dominated by T) list FNDECL as its
985 BV_FN. DELTA is the required constant adjustment from the `this'
986 pointer where the vtable entry appears to the `this' required when
987 the function is actually called. */
989 static void
991 tree binfo,
992 tree fndecl,
993 tree delta,
995 {
996 tree v;
1002 {
1003 /* We need a new vtable for BINFO. */
1005 {
1006 /* If we really did make a new vtable, we also made a copy
1007 of the BINFO_VIRTUALS list. Now, we have to find the
1008 corresponding entry in that list. */
1013 }
1018 }
1019 }
1021 \f
1022 /* Check if the object parameter of an iobj member function corresponds to
1023 another parameter type. CONTEXT is the class that the implicit object
1024 parameter is considered to refer to. */
1026 bool
1028 {
1031 /* If the iobj member function was introduced with a using declaration, the
1032 type of its object parameter is considered to be that of the class it was
1033 introduced into.
1035 [over.match.funcs.general.4]
1036 For non-conversion functions that are implicit object member
1037 functions nominated by a using-declaration in a derived class, the
1038 function is considered to be a member of the derived class for the purpose
1039 of defining the type of the implicit object parameter.
1041 Unfortunately, because of this rule, we can't just compare the xobj member
1042 function's DECL_CONTEXT to its object parameter.
1044 struct S;
1046 struct B {
1047 int f(this S&) { return 5; }
1048 };
1050 struct S : B {
1051 using B::f;
1052 int f() { return 10; }
1053 };
1055 The using declaration does not change the object parameter of B::f as it
1056 is an xobj member function. However, its object parameter still
1057 corresponds to S::f as it was declared with an object parameter of type
1058 S const&. The DECL_CONTEXT of B::f is B, so if we compare the type of the
1059 object parameter to that, it will not match. If we naively assume a
1060 different type from the DECL_CONTEXT for an xobj parameter means that the
1061 object parameters do not correspond, then the object parameters in the
1062 above example will be considered non-corresponding.
1064 As a result of this, B::f would incorrectly not be discarded, causing an
1065 ambiguity when f is called on an object of type S.
1067 This also impacts member functions with constraints as in the following
1068 example.
1070 template<typename = void>
1071 struct S;
1073 template<typename = void>
1074 struct B {
1075 int f(this S<>&) requires true { return 5; }
1076 };
1078 template<typename>
1079 struct S : B<> {
1080 using B<>::f;
1081 int f() { return 10; }
1082 };
1084 Once again, if we compare the DECL_CONTEXT of B<>::f to it's xobj
1085 parameter, it would not match. If the object parameters do not
1086 correspond, constraints are not taken into account, so in this example we
1087 would (probably) get an ambiguous lookup instead of correctly picking
1088 B<>::f.
1090 Because of this caveat, we must actually compare the type of the iobj
1091 parameter to the type of the xobj parameter, shortcuts will have these
1092 edge cases.
1094 Aside from the more complex reasons above, this logic also implicitly
1095 handles xobj parameters of pointer type, we don't have to explicitly
1096 check for that case. */
1102 /* We don't get to bail yet even if we have a by-value xobj parameter,
1103 a by-value xobj parameter can correspond to an iobj parameter provided the
1104 iobj member function is not declared with a reference qualifier.
1106 From this point on, we know we are dealing with an xobj parameter that has
1107 an object parameter of the same type as the class it was declared in.
1108 We still don't know if we have a reference or by-value parameter yet
1109 though. */
1112 /* We only care about cv qualifiers when determining correspondence. */
1116 /* We need to ignore the ref qualifier of the xobj parameter if the iobj
1117 member function lacks a ref qualifier.
1119 [basic.scope.scope.3]
1120 Two non-static member functions have corresponding object parameters if:
1121 -- exactly one is an implicit object member function with no ref-qualifier
1122 and the types of their object parameters ([dcl.fct]), after removing
1123 top-level references, are the same, or
1124 -- their object parameters have the same type.
1126 The cv qualifiers of a by-value parameter are supposed to be discarded, so
1127 we ignore them.
1129 [dcl.fct.5]
1130 After producing the list of parameter types, any top-level cv-qualifiers
1131 modifying a parameter type are deleted when forming the function type.
1133 However, they still need to be taken into account when our xobj parameter
1134 is a reference that is being ignored (according to [basic.scope.scope.3]
1135 quoted above), but when we are actually dealing with a by-value xobj
1136 parameter we can proceed following this table.
1137 | iobj | xobj | equal |
1138 | none | none | X |
1139 | none | c | X |
1140 | none | v | X |
1141 | none | cv | X |
1142 | c | none | O |
1143 | c | c | O |
1144 | c | v | O |
1145 | c | cv | O |
1146 | v | none | O |
1147 | v | c | O |
1148 | v | v | O |
1149 | v | cv | O |
1150 | cv | none | O |
1151 | cv | c | O |
1152 | cv | v | O |
1153 | cv | cv | O |
1155 Additionally, if the iobj member function is ref qualified, we aren't
1156 ignoring the ref qualifier of the iobj parameter, so we can't be dealing
1157 with correspondence in that case either.
1159 So to recap, if we have a by-value xobj parameter, we know for sure that
1160 we aren't dealing with corresponding object parameters if the iobj member
1161 function has any cv-ref qualifiers. The only case where we might still be
1162 dealing with corresponding object parameters is when the iobj member
1163 function lacks any cv-ref qualification. */
1165 {
1168 }
1169 else
1170 {
1171 /* We are dealing with an xobj parameter that is a reference now, but due
1172 to [basic.scope.scope.3] we need to ignore its ref qual. */
1180 /* Even if we are ignoring the reference qualifier, the xobj parameter
1181 was still a reference so we still take the cv qualifiers into
1182 account. */
1183 cp_cv_quals const xobj_cv_quals
1186 /* Finally, if the qualifications don't match exactly, the object
1187 parameters don't correspond. */
1191 }
1192 /* If we got past everything else, the object parameters of fn1 and fn2
1193 definitely correspond. */
1195 }
1197 /* True if FN and METHOD have corresponding object parms per
1198 [basic.scope.scope], or if one of them is a static member function (which
1199 are considered to have an object parm that corresponds to any other).
1200 CONTEXT is the class that an implicit object member function is considered
1201 to be a member of for the purpose of this comparison, per
1202 [over.match.funcs]. */
1204 bool
1206 {
1210 /* Compare the quals on the 'this' parm. Don't compare
1211 the whole types, as used functions are treated as
1212 coming from the using class in overload resolution. */
1215 {
1216 /* Either both or neither need to be ref-qualified for
1217 differing quals to allow overloading. */
1224 }
1225 /* Treat a static member function as corresponding to any object parm. */
1228 /* Handle special correspondence rules for xobj vs xobj and xobj vs iobj
1229 member function declarations.
1230 We don't worry about static member functions here. */
1233 {
1235 {
1237 };
1238 /* We skip the object parameter below, check it here instead of
1239 making changes to that code. */
1244 }
1245 else
1246 {
1252 }
1255 }
1257 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
1258 METHOD is being injected via a using_decl. Returns true if the
1259 method could be added to the method vec. */
1261 bool
1263 {
1272 /* See below. */
1275 /* Check to see if we've already got this method. */
1277 {
1283 /* Two using-declarations can coexist, we'll complain about ambiguity in
1284 overload resolution. */
1286 /* Except handle inherited constructors specially. */
1288 {
1290 /* Don't add the same one twice. */
1293 }
1295 /* [over.load] Member function declarations with the
1296 same name and the same parameter types cannot be
1297 overloaded if any of them is a static member
1298 function declaration.
1300 [over.load] Member function declarations with the same name and
1301 the same parameter-type-list as well as member function template
1302 declarations with the same name, the same parameter-type-list, and
1303 the same template parameter lists cannot be overloaded if any of
1304 them, but not all, have a ref-qualifier.
1306 [namespace.udecl] When a using-declaration brings names
1307 from a base class into a derived class scope, member
1308 functions in the derived class override and/or hide member
1309 functions with the same name and parameter types in a base
1310 class (rather than conflicting). */
1320 /* Templates and conversion ops must match return types. */
1325 /* For templates, the template parameters must be identical. */
1327 {
1334 }
1343 /* Bring back parameters omitted from an inherited ctor. The
1344 method and the function can have different omittedness. */
1348 parms2 = (FUNCTION_FIRST_USER_PARMTYPE
1355 {
1357 /* We can't check satisfaction in dependent context, wait until
1358 the class is instantiated. */
1366 /* Member function templates and non-special member functions
1367 coexist if they are not equivalently constrained. A member
1368 function is not hidden by an inherited constructor. */
1371 /* P0848: For special member functions, deleted, unsatisfied, or
1372 less constrained overloads are ineligible. We implement this
1373 by removing them from CLASSTYPE_MEMBER_VEC. Destructors don't
1374 use the notion of eligibility, and the selected destructor can
1375 be deleted, but removing unsatisfied or less constrained
1376 overloads has the same effect as overload resolution. */
1386 else
1389 /* Leave FN in the method vec, discard METHOD. */
1392 {
1393 /* Remove FN, add METHOD. */
1396 }
1397 else
1398 /* Let them coexist for now. */
1400 }
1402 /* If these are versions of the same function, process and
1403 move on. */
1409 {
1411 /* Defer to the other function. */
1417 {
1419 {
1420 /* Inheriting the same constructor along different
1421 paths, combine them. */
1422 SET_DECL_INHERITED_CTOR
1425 /* And discard the new one. */
1427 }
1428 else
1429 /* Inherited ctors can coexist until overload
1430 resolution. */
1432 }
1434 auto_diagnostic_group d;
1440 basef);
1442 }
1445 /* Defer to the local function. */
1448 || (flag_new_inheriting_ctors
1450 {
1451 /* Remove the inherited function. */
1454 }
1455 else
1456 {
1457 auto_diagnostic_group d;
1463 }
1464 }
1475 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1481 }
1483 /* Subroutines of finish_struct. */
1485 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1486 legit, otherwise return 0. */
1488 static int
1490 {
1491 tree elem;
1499 {
1501 {
1505 else
1508 }
1509 else
1510 {
1511 /* They're changing the access to the same thing they changed
1512 it to before. That's OK. */
1513 ;
1514 }
1515 }
1516 else
1517 {
1519 tf_warning_or_error);
1522 }
1524 }
1526 /* Return the access node for DECL's access in its enclosing class. */
1528 tree
1530 {
1534 }
1536 /* If DECL is a non-dependent using of non-ctor function members, push them
1537 and return true, otherwise return false. Called from
1538 finish_member_declaration. */
1540 bool
1542 {
1549 /* Add the functions to CLASSTYPE_MEMBER_VEC so that overload resolution
1550 works within the class body. */
1552 {
1554 /* Inheriting constructors are handled separately. */
1562 /* If add_method returns false because f was already declared, look
1563 for a duplicate using-declaration. */
1564 else
1569 {
1572 }
1573 }
1575 }
1577 /* Process the USING_DECL, which is a member of T. */
1579 static void
1581 {
1589 /* Handled in maybe_push_used_methods. */
1594 tf_warning_or_error);
1596 {
1601 else
1603 }
1606 ;
1608 {
1609 auto_diagnostic_group d;
1616 }
1618 {
1619 auto_diagnostic_group d;
1626 }
1631 /* Make type T see field decl FDECL with access ACCESS. */
1633 {
1634 /* C++20 using enum can import non-inherited enumerators into class
1635 scope. We implement that by making a copy of the CONST_DECL for which
1636 CONST_DECL_USING_P is true. */
1643 /* We emitted debug info for the USING_DECL above; make sure we don't
1644 also emit anything for this clone. */
1649 }
1650 else
1652 }
1653 \f
1654 /* Data structure for find_abi_tags_r, below. */
1656 struct abi_tag_data
1657 {
1661 };
1663 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1664 in the context of P. TAG can be either an identifier (the DECL_NAME of
1665 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1667 static void
1669 {
1671 {
1673 {
1674 /* We're collecting tags from template arguments or from
1675 the type of a variable or function return type. */
1678 /* Don't inherit this tag multiple times. */
1682 {
1683 /* Tags inherited from type template arguments are only used
1684 to avoid warnings. */
1687 }
1688 /* For functions and variables we want to warn, too. */
1689 }
1691 /* Otherwise we're diagnosing missing tags. */
1693 {
1694 auto_diagnostic_group d;
1699 }
1701 {
1702 auto_diagnostic_group d;
1706 }
1708 {
1709 auto_diagnostic_group d;
1714 }
1715 else
1716 {
1717 auto_diagnostic_group d;
1721 {
1725 }
1726 }
1727 }
1728 }
1730 /* Find all the ABI tags in the attribute list ATTR and either call
1731 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1733 static void
1735 {
1742 {
1747 else
1749 }
1750 }
1752 /* Find all the ABI tags on T and its enclosing scopes and either call
1753 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1755 static void
1757 {
1759 {
1760 tree attr;
1762 {
1765 }
1766 else
1767 {
1770 }
1772 }
1773 }
1775 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1776 types with ABI tags, add the corresponding identifiers to the VEC in
1777 *DATA and set IDENTIFIER_MARKED. */
1779 static tree
1781 {
1783 /* Tell cp_walk_subtrees to look though typedefs. [PR98481] */
1789 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1790 anyway, but let's make sure of it. */
1798 }
1800 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1801 IDENTIFIER_MARKED on its ABI tags. */
1803 static tree
1805 {
1807 /* Tell cp_walk_subtrees to look though typedefs. */
1813 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1814 anyway, but let's make sure of it. */
1822 }
1824 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1825 scopes. */
1827 static void
1829 {
1832 {
1835 {
1836 /* Template arguments are part of the signature. */
1839 {
1842 }
1843 }
1845 /* A function's parameter types are part of the signature, so
1846 we don't need to inherit any tags that are also in them. */
1851 }
1852 }
1854 /* Check that T has all the ABI tags that subobject SUBOB has, or
1855 warn if not. If T is a (variable or function) declaration, also
1856 return any missing tags, and add them to T if JUST_CHECKING is false. */
1858 static tree
1860 {
1868 /* No need to worry about things local to this TU. */
1884 {
1887 }
1888 else
1889 {
1893 else
1896 }
1901 }
1903 /* Check that DECL has all the ABI tags that are used in parts of its type
1904 that are not reflected in its mangled name. */
1906 void
1908 {
1915 }
1917 /* Return any ABI tags that are used in parts of the type of DECL
1918 that are not reflected in its mangled name. This function is only
1919 used in backward-compatible mangling for ABI <11. */
1921 tree
1923 {
1927 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1928 that we can use this function for setting need_abi_warning
1929 regardless of the current flag_abi_version. */
1932 else
1934 }
1936 void
1938 {
1948 {
1951 {
1955 }
1956 }
1958 // If we found some tags on our template arguments, add them to our
1959 // abi_tag attribute.
1961 {
1965 else
1968 }
1971 }
1973 /* Return true, iff class T has a non-virtual destructor that is
1974 accessible from outside the class heirarchy (i.e. is public, or
1975 there's a suitable friend. */
1977 static bool
1979 {
1982 /* An implicitly declared destructor is always public. And,
1983 if it were virtual, we would have created it by now. */
1998 }
2000 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
2001 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
2002 properties of the bases. */
2004 static void
2008 {
2012 tree base_binfo;
2013 tree binfo;
2023 {
2032 /* If any base class is non-literal, so is the derived class. */
2036 /* If the base class doesn't have copy constructors or
2037 assignment operators that take const references, then the
2038 derived class cannot have such a member automatically
2039 generated. */
2048 /* A virtual base does not effect nearly emptiness. */
2049 ;
2051 {
2053 /* And if there is more than one nearly empty base, then the
2054 derived class is not nearly empty either. */
2056 else
2057 /* Remember we've seen one. */
2059 }
2061 /* If the base class is not empty or nearly empty, then this
2062 class cannot be nearly empty. */
2065 /* A lot of properties from the bases also apply to the derived
2066 class. */
2083 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
2086 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
2092 /* A standard-layout class is a class that:
2093 ...
2094 * has no non-standard-layout base classes, */
2097 {
2098 tree basefield;
2099 /* ...has no base classes of the same type as the first non-static
2100 data member... */
2102 && (same_type_ignoring_top_level_qualifiers_p
2105 /* DR 1813:
2106 ...has at most one base class subobject of any given type... */
2109 else
2110 /* ...has all non-static data members and bit-fields in the class
2111 and its base classes first declared in the same class. */
2117 {
2120 else
2123 }
2124 }
2126 /* Don't bother collecting tm attributes if transactional memory
2127 support is not enabled. */
2129 {
2133 }
2136 }
2138 /* If one of the base classes had TM attributes, and the current class
2139 doesn't define its own, then the current class inherits one. */
2141 {
2144 }
2145 }
2147 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
2148 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
2149 that have had a nearly-empty virtual primary base stolen by some
2150 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
2151 T. */
2153 static void
2155 {
2159 tree base_binfo;
2161 /* Determine the primary bases of our bases. */
2164 {
2167 /* See if we're the non-virtual primary of our inheritance
2168 chain. */
2170 {
2177 /* We are the primary binfo. */
2179 }
2180 /* Determine if we have a virtual primary base, and mark it so.
2181 */
2183 {
2187 /* Someone already claimed this base. */
2189 else
2190 {
2191 tree delta;
2196 /* A virtual binfo might have been copied from within
2197 another hierarchy. As we're about to use it as a
2198 primary base, make sure the offsets match. */
2206 }
2207 }
2208 }
2210 /* First look for a dynamic direct non-virtual base. */
2212 {
2216 {
2219 }
2220 }
2222 /* A "nearly-empty" virtual base class can be the primary base
2223 class, if no non-virtual polymorphic base can be found. Look for
2224 a nearly-empty virtual dynamic base that is not already a primary
2225 base of something in the hierarchy. If there is no such base,
2226 just pick the first nearly-empty virtual base. */
2232 {
2234 {
2235 /* Found one that is not primary. */
2238 }
2240 /* Remember the first candidate. */
2242 }
2244 found:
2245 /* If we've got a primary base, use it. */
2247 {
2252 /* We are stealing a primary base. */
2256 {
2257 tree delta;
2260 /* A virtual binfo might have been copied from within
2261 another hierarchy. As we're about to use it as a primary
2262 base, make sure the offsets match. */
2267 }
2274 }
2275 }
2277 /* Update the variant types of T. */
2279 void
2281 {
2286 variant;
2288 {
2289 /* These fields are in the _TYPE part of the node, not in
2290 the TYPE_LANG_SPECIFIC component, so they are not shared. */
2301 /* Copy whatever these are holding today. */
2311 {
2314 }
2320 }
2321 }
2323 /* KLASS is a class that we're applying may_alias to after the body is
2324 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
2325 canonical type(s) will be implicitly updated. */
2327 static void
2329 {
2338 }
2340 /* Early variant fixups: we apply attributes at the beginning of the class
2341 definition, and we need to fix up any variants that have already been
2342 made via elaborated-type-specifier so that check_qualified_type works. */
2344 void
2346 {
2347 tree variants;
2362 variants;
2364 {
2365 /* These are the two fields that check_qualified_type looks at and
2366 are affected by attributes. */
2371 else
2377 }
2378 }
2379 \f
2380 /* Set memoizing fields and bits of T (and its variants) for later
2381 use. */
2383 static void
2385 {
2386 /* If this type has a copy constructor or a destructor, force its
2387 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2388 nonzero. This will cause it to be passed by invisible reference
2389 and prevent it from being returned in a register. */
2392 {
2396 }
2399 /* For a class w/o baseclasses, 'finish_struct' has set
2400 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2401 Similarly for a class whose base classes do not have vtables.
2402 When neither of these is true, we might have removed abstract
2403 virtuals (by providing a definition), added some (by declaring
2404 new ones), or redeclared ones from a base class. We need to
2405 recalculate what's really an abstract virtual at this point (by
2406 looking in the vtables). */
2409 /* Fix up variants (if any). */
2411 }
2413 /* Issue warnings about T having private constructors, but no friends,
2414 and so forth.
2416 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2417 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2418 non-private static member functions. */
2420 static void
2422 {
2428 /* If the class has friends, those entities might create and
2429 access instances, so we should not warn. */
2432 /* We will have warned when the template was declared; there's
2433 no need to warn on every instantiation. */
2435 /* There's no reason to even consider warning about this
2436 class. */
2439 /* We only issue one warning, if more than one applies, because
2440 otherwise, on code like:
2442 class A {
2443 // Oops - forgot `public:'
2444 A();
2445 A(const A&);
2446 ~A();
2447 };
2449 we warn several times about essentially the same problem. */
2451 /* Check to see if all (non-constructor, non-destructor) member
2452 functions are private. (Since there are no friends or
2453 non-private statics, we can't ever call any of the private member
2454 functions.) */
2463 /* We're not interested in compiler-generated methods; they don't
2466 {
2468 /* A non-private static member function is just like a
2469 friend; it can create and invoke private member
2470 functions, and be accessed without a class
2471 instance. */
2475 /* Keep searching for a static member function. */
2476 }
2481 {
2482 /* There are no non-private methods, and there's at least one
2483 private member function that isn't a constructor or
2484 destructor. (If all the private members are
2485 constructors/destructors we want to use the code below that
2486 issues error messages specifically referring to
2487 constructors/destructors.) */
2493 {
2496 }
2498 {
2502 }
2503 }
2505 /* Even if some of the member functions are non-private, the class
2506 won't be useful for much if all the constructors or destructors
2507 are private: such an object can never be created or destroyed. */
2510 {
2513 t);
2515 }
2517 /* Warn about classes that have private constructors and no friends. */
2519 /* Implicitly generated constructors are always public. */
2521 {
2524 /* If a non-template class does not define a copy
2525 constructor, one is defined for it, enabling it to avoid
2526 this warning. For a template class, this does not
2527 happen, and so we would normally get a warning on:
2529 template <class T> class C { private: C(); };
2531 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2532 complete non-template or fully instantiated classes have this
2533 flag set. */
2536 else
2541 /* Ideally, we wouldn't count any constructor that takes
2542 an argument of the class type as a parameter, because
2543 such things cannot be used to construct an instance of
2544 the class unless you already have one. */
2546 else
2547 {
2550 }
2553 {
2554 auto_diagnostic_group d;
2556 "%q#T only defines private constructors and has "
2563 }
2564 }
2565 }
2567 /* Make BINFO's vtable have N entries, including RTTI entries,
2568 vbase and vcall offsets, etc. Set its type and call the back end
2569 to lay it out. */
2571 static void
2573 {
2574 tree atype;
2575 tree vtable;
2580 /* We may have to grow the vtable. */
2583 {
2587 }
2588 }
2590 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2591 have the same signature. */
2593 int
2595 {
2596 /* One destructor overrides another if they are the same kind of
2597 destructor. */
2601 /* But a non-destructor never overrides a destructor, nor vice
2602 versa, nor do different kinds of destructors override
2603 one-another. For example, a complete object destructor does not
2604 override a deleting destructor. */
2613 {
2621 }
2623 }
2625 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2626 subobject. */
2628 static bool
2630 {
2631 tree probe;
2634 {
2638 /* If we meet a virtual base, we can't follow the inheritance
2639 any more. See if the complete type of DERIVED contains
2640 such a virtual base. */
2643 }
2645 }
2648 /* The function for which we are trying to find a final overrider. */
2649 tree fn;
2650 /* The base class in which the function was declared. */
2651 tree declaring_base;
2652 /* The candidate overriders. */
2653 tree candidates;
2654 /* Path to most derived. */
2656 };
2658 /* Add the overrider along the current path to FFOD->CANDIDATES.
2659 Returns true if an overrider was found; false otherwise. */
2661 static bool
2665 {
2666 tree method;
2668 /* If BINFO is not the most derived type, try a more derived class.
2669 A definition there will overrider a definition here. */
2671 {
2672 depth--;
2676 }
2680 {
2683 /* Remove any candidates overridden by this new function. */
2685 {
2686 /* If *CANDIDATE overrides METHOD, then METHOD
2687 cannot override anything else on the list. */
2690 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2693 else
2695 }
2697 /* Add the new function. */
2700 }
2703 }
2705 /* Called from find_final_overrider via dfs_walk. */
2707 static tree
2709 {
2717 }
2719 static tree
2721 {
2726 }
2728 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2729 FN and whose TREE_VALUE is the binfo for the base where the
2730 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2731 DERIVED) is the base object in which FN is declared. */
2733 static tree
2735 {
2736 find_final_overrider_data ffod;
2738 /* Getting this right is a little tricky. This is valid:
2740 struct S { virtual void f (); };
2741 struct T { virtual void f (); };
2742 struct U : public S, public T { };
2744 even though calling `f' in `U' is ambiguous. But,
2746 struct R { virtual void f(); };
2747 struct S : virtual public R { virtual void f (); };
2748 struct T : virtual public R { virtual void f (); };
2749 struct U : public S, public T { };
2751 is not -- there's no way to decide whether to put `S::f' or
2752 `T::f' in the vtable for `R'.
2754 The solution is to look at all paths to BINFO. If we find
2755 different overriders along any two, then there is a problem. */
2759 /* Determine the depth of the hierarchy. */
2768 /* If there was no winner, issue an error message. */
2773 }
2775 /* Return the index of the vcall offset for FN when TYPE is used as a
2776 virtual base. */
2778 static tree
2780 {
2782 tree_pair_p p;
2790 /* There should always be an appropriate index. */
2792 }
2794 /* Given a DECL_VINDEX of a virtual function found in BINFO, return the final
2795 overrider at that index in the vtable. This should only be used when we
2796 know that BINFO is correct for the dynamic type of the object. */
2798 tree
2800 {
2805 /* BINFO_VIRTUALS in a primary base isn't accurate, find the derived
2806 class that actually owns the vtable. */
2810 }
2812 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2813 dominated by T. FN is the old function; VIRTUALS points to the
2814 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2815 of that entry in the list. */
2817 static void
2820 {
2821 tree b;
2822 tree overrider;
2823 tree delta;
2824 tree virtual_base;
2825 tree first_defn;
2831 /* Find the nearest primary base (possibly binfo itself) which defines
2832 this function; this is the class the caller will convert to when
2833 calling FN through BINFO. */
2835 {
2840 /* The nearest definition is from a lost primary. */
2843 }
2846 /* Find the final overrider. */
2849 {
2852 }
2855 /* Check for adjusting covariant return types. */
2863 /* If the overrider is invalid, don't even try. */
2865 {
2866 /* If FN is a covariant thunk, we must figure out the adjustment
2867 to the final base FN was converting to. As OVERRIDER_TARGET might
2868 also be converting to the return type of FN, we have to
2869 combine the two conversions here. */
2876 {
2880 }
2881 else
2885 /* Find the equivalent binfo within the return type of the
2886 overriding function. We will want the vbase offset from
2887 there. */
2889 over_return);
2892 {
2893 /* There was no existing virtual thunk (which takes
2894 precedence). So find the binfo of the base function's
2895 return type within the overriding function's return type.
2896 Fortunately we know the covariancy is valid (it
2897 has already been checked), so we can just iterate along
2898 the binfos, which have been chained in inheritance graph
2899 order. Of course it is lame that we have to repeat the
2900 search here anyway -- we should really be caching pieces
2901 of the vtable and avoiding this repeated work. */
2905 /* Find the base binfo within the overriding function's
2906 return type. We will always find a thunk_binfo, except
2907 when the covariancy is invalid (which we will have
2908 already diagnosed). */
2917 /* See if virtual inheritance is involved. */
2919 virtual_offset;
2926 {
2930 {
2931 /* We convert via virtual base. Adjust the fixed
2932 offset to be from there. */
2933 offset =
2937 }
2939 /* There was an existing fixed offset, this must be
2940 from the base just converted to, and the base the
2941 FN was thunking to. */
2943 else
2945 }
2946 }
2949 /* Replace the overriding function with a covariant thunk. We
2950 will emit the overriding function in its own slot as
2951 well. */
2954 }
2955 else
2959 /* If we need a covariant thunk, then we may need to adjust first_defn.
2960 The ABI specifies that the thunks emitted with a function are
2961 determined by which bases the function overrides, so we need to be
2962 sure that we're using a thunk for some overridden base; even if we
2963 know that the necessary this adjustment is zero, there may not be an
2964 appropriate zero-this-adjustment thunk for us to use since thunks for
2965 overriding virtual bases always use the vcall offset.
2967 Furthermore, just choosing any base that overrides this function isn't
2968 quite right, as this slot won't be used for calls through a type that
2969 puts a covariant thunk here. Calling the function through such a type
2970 will use a different slot, and that slot is the one that determines
2971 the thunk emitted for that base.
2973 So, keep looking until we find the base that we're really overriding
2974 in this slot: the nearest primary base that doesn't use a covariant
2975 thunk in this slot. */
2977 {
2979 /* We already know that the overrider needs a covariant thunk. */
2982 {
2989 }
2991 }
2993 /* Assume that we will produce a thunk that convert all the way to
2994 the final overrider, and not to an intermediate virtual base. */
2997 /* See if we can convert to an intermediate virtual base first, and then
2998 use the vcall offset located there to finish the conversion. */
3000 {
3001 /* If we find the final overrider, then we can stop
3002 walking. */
3007 /* If we find a virtual base, and we haven't yet found the
3008 overrider, then there is a virtual base between the
3009 declaring base (first_defn) and the final overrider. */
3011 {
3014 }
3015 }
3017 /* Compute the constant adjustment to the `this' pointer. The
3018 `this' pointer, when this function is called, will point at BINFO
3019 (or one of its primary bases, which are at the same offset). */
3021 /* The `this' pointer needs to be adjusted from the declaration to
3022 the nearest virtual base. */
3027 /* If the nearest definition is in a lost primary, we don't need an
3028 entry in our vtable. Except possibly in a constructor vtable,
3029 if we happen to get our primary back. In that case, the offset
3030 will be zero, as it will be a primary base. */
3032 else
3033 /* The `this' pointer needs to be adjusted from pointing to
3034 BINFO to pointing at the base where the final overrider
3035 appears. */
3046 else
3050 }
3052 /* Called from modify_all_vtables via dfs_walk. */
3054 static tree
3056 {
3058 tree virtuals;
3059 tree old_virtuals;
3063 /* A base without a vtable needs no modification, and its bases
3064 are uninteresting. */
3069 /* Don't do the primary vtable, if it's new. */
3073 /* There's no need to modify the vtable for a non-virtual primary
3074 base; we're not going to use that vtable anyhow. We do still
3075 need to do this for virtual primary bases, as they could become
3076 non-primary in a construction vtable. */
3081 /* Now, go through each of the virtual functions in the virtual
3082 function table for BINFO. Find the final overrider, and update
3083 the BINFO_VIRTUALS list appropriately. */
3086 virtuals;
3090 binfo,
3095 }
3097 /* Update all of the primary and secondary vtables for T. Create new
3098 vtables as required, and initialize their RTTI information. Each
3099 of the functions in VIRTUALS is declared in T and may override a
3100 virtual function from a base class; find and modify the appropriate
3101 entries to point to the overriding functions. Returns a list, in
3102 declaration order, of the virtual functions that are declared in T,
3103 but do not appear in the primary base class vtable, and which
3104 should therefore be appended to the end of the vtable for T. */
3106 static tree
3108 {
3112 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
3116 /* Update all of the vtables. */
3119 /* Add virtual functions not already in our primary vtable. These
3120 will be both those introduced by this class, and those overridden
3121 from secondary bases. It does not include virtuals merely
3122 inherited from secondary bases. */
3124 {
3129 {
3130 /* We don't need to adjust the `this' pointer when
3131 calling this function. */
3135 /* This is a function not already in our vtable. Keep it. */
3137 }
3138 else
3139 /* We've already got an entry for this function. Skip it. */
3141 }
3144 }
3146 /* Get the base virtual function declarations in T that have the
3147 indicated NAME. */
3149 static void
3151 {
3154 /* Find virtual functions in T with the indicated NAME. */
3156 {
3158 {
3161 }
3162 }
3169 {
3172 }
3173 }
3175 /* If this method overrides a virtual method from a base, then mark
3176 this member function as being virtual as well. Do 'final' and
3177 'override' checks too. */
3179 void
3181 {
3183 /* In [temp.mem] we have:
3185 A specialization of a member function template does not
3186 override a virtual function from a base class. */
3189 /* IDENTIFIER_VIRTUAL_P indicates whether the name has ever been
3190 used for a vfunc. That avoids the expensive look_for_overrides
3191 call that when we know there's nothing to find. As conversion
3192 operators for the same type can have distinct identifiers, we
3193 cannot optimize those in that way. */
3197 /* Check staticness after we've checked if we 'override'. */
3199 {
3200 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
3201 the error_mark_node so that we know it is an overriding
3202 function. */
3211 }
3216 {
3217 /* Remember this identifier is virtual name. */
3221 /* It's a new vfunc. */
3226 }
3229 }
3231 /* Warn about hidden virtual functions that are not overridden in t.
3232 We know that constructors and destructors don't apply. */
3234 static void
3236 {
3239 {
3247 tree base_binfo;
3248 tree binfo;
3254 /* Iterate through all of the base classes looking for possibly
3255 hidden functions. */
3258 {
3261 }
3263 /* If there are no functions to hide, continue. */
3267 /* Remove any overridden functions. */
3270 {
3274 {
3275 /* If the method from the base class has the same
3276 signature as the method from the derived class, it
3277 has been overridden. Note that we can't move on
3278 after finding one match: fndecl might override
3279 multiple base fns. */
3283 {
3286 }
3287 }
3290 }
3293 /* All the derived fns override base virtuals. */
3296 /* Now give a warning for all base functions without overriders,
3297 as they are hidden. */
3300 {
3301 auto_diagnostic_group d;
3302 /* Here we know it is a hider, and no overrider exists. */
3304 OPT_Woverloaded_virtual_,
3307 }
3308 }
3309 }
3311 /* Recursive helper for finish_struct_anon. */
3313 static void
3315 {
3317 {
3318 /* We're generally only interested in entities the user
3319 declared, but we also find nested classes by noticing
3320 the TYPE_DECL that we create implicitly. You're
3321 allowed to put one anonymous union inside another,
3322 though, so we explicitly tolerate that. We use
3323 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
3324 we also allow unnamed types used for defining fields. */
3333 /* Recurse into the anonymous aggregates to correctly handle
3334 access control (c++/24926):
3336 class A {
3337 union {
3338 union {
3339 int i;
3340 };
3341 };
3342 };
3344 int j=A().i; */
3348 }
3349 }
3351 /* Fix up any anonymous union/struct members of T. */
3353 static void
3355 {
3357 {
3366 }
3367 }
3369 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
3370 will be used later during class template instantiation.
3371 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
3372 a non-static member data (FIELD_DECL), a member function
3373 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
3374 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
3375 When FRIEND_P is nonzero, T is either a friend class
3376 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
3377 (FUNCTION_DECL, TEMPLATE_DECL). */
3379 void
3381 {
3384 {
3389 }
3390 }
3392 /* This function is called from declare_virt_assop_and_dtor via
3393 dfs_walk_all.
3395 DATA is a type that direcly or indirectly inherits the base
3396 represented by BINFO. If BINFO contains a virtual assignment [copy
3397 assignment or move assigment] operator or a virtual constructor,
3398 declare that function in DATA if it hasn't been already declared. */
3400 static tree
3402 {
3410 /* A base without a vtable needs no modification, and its bases
3411 are uninteresting. */
3415 /* If this is a primary base, then we have already looked at the
3416 virtual functions of its vtable. */
3420 {
3424 {
3429 }
3433 }
3436 }
3438 /* If the class type T has a direct or indirect base that contains a
3439 virtual assignment operator or a virtual destructor, declare that
3440 function in T if it hasn't been already declared. */
3442 static void
3444 {
3452 dfs_declare_virt_assop_and_dtor,
3454 }
3456 /* Declare the inheriting constructor for class T inherited from base
3457 constructor CTOR with the parameter array PARMS of size NPARMS. */
3459 static void
3461 {
3464 /* We don't declare an inheriting ctor that would be a default,
3465 copy or move ctor for derived or base. */
3470 {
3474 }
3483 {
3486 }
3487 }
3489 /* Declare all the inheriting constructors for class T inherited from base
3490 constructor CTOR. */
3492 static void
3494 {
3498 {
3503 }
3508 {
3512 }
3515 {
3516 auto_diagnostic_group d;
3520 }
3521 }
3523 /* Implicitly declare T(). */
3525 static void
3527 {
3532 /* Don't force the declaration to get a hard answer; if the
3533 definition would have made the class non-literal, it will still be
3534 non-literal because of the base or member in question, and that
3535 gives a better diagnostic. */
3537 }
3539 /* Create default constructors, assignment operators, and so forth for
3540 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3541 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3542 the class cannot have a default constructor, copy constructor
3543 taking a const reference argument, or an assignment operator taking
3544 a const reference, respectively. */
3546 static void
3550 {
3551 /* Destructor. */
3553 /* In general, we create destructors lazily. */
3562 /* [class.ctor]
3564 If there is no user-declared constructor for a class, a default
3565 constructor is implicitly declared. */
3569 /* [class.ctor]
3571 If a class definition does not explicitly declare a copy
3572 constructor, one is declared implicitly. */
3574 {
3580 }
3582 /* If there is no assignment operator, one will be created if and
3583 when it is needed. For now, just record whether or not the type
3584 of the parameter to the assignment operator will be a const or
3585 non-const reference. */
3587 {
3593 }
3595 /* We can't be lazy about declaring functions that might override
3596 a virtual function from a base class. */
3599 /* If the class definition does not explicitly declare an == operator
3600 function, but declares a defaulted three-way comparison operator function,
3601 an == operator function is declared implicitly. */
3604 {
3606 NULL_TREE);
3611 else
3612 {
3616 }
3618 }
3621 {
3625 {
3626 /* declare, then remove the decl */
3631 {
3633 /* CWG2799: Inheriting a default constructor gives us a default
3634 constructor, not just an inherited constructor. */
3637 }
3640 }
3641 else
3643 }
3644 }
3646 /* Cache of enum_min_precision values. */
3649 /* Return the minimum precision of a bit-field needed to store all
3650 enumerators of ENUMERAL_TYPE TYPE. */
3652 static int
3654 {
3656 /* For unscoped enums without fixed underlying type and without mode
3657 attribute we can just use precision of the underlying type. */
3673 {
3677 {
3688 }
3689 }
3690 else
3698 }
3700 /* FIELD is a bit-field. We are finishing the processing for its
3701 enclosing type. Issue any appropriate messages and set appropriate
3702 flags. Returns false if an error has been diagnosed. */
3704 static bool
3706 {
3708 tree w;
3710 /* Extract the declared width of the bitfield, which has been
3711 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3714 /* Remove the bit-field width indicator so that the rest of the
3715 compiler does not treat that value as a qualifier. */
3718 /* Detect invalid bit-field type. */
3720 {
3724 }
3725 else
3726 {
3728 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3731 /* detect invalid field size. */
3737 {
3740 }
3742 {
3745 }
3747 {
3750 }
3760 {
3766 }
3767 }
3770 {
3774 }
3775 else
3776 {
3777 /* Non-bit-fields are aligned for their type. */
3781 }
3782 }
3784 /* FIELD is a non bit-field. We are finishing the processing for its
3785 enclosing type T. Issue any appropriate messages and set appropriate
3786 flags. */
3788 static bool
3790 tree t,
3793 {
3797 /* In C++98 an anonymous union cannot contain any fields which would change
3798 the settings of CANT_HAVE_CONST_CTOR and friends. */
3800 ;
3801 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3802 structs. So, we recurse through their fields here. */
3804 {
3809 cant_have_const_ctor,
3810 no_const_asn_ref);
3811 }
3812 /* Check members with class type for constructors, destructors,
3813 etc. */
3815 {
3816 /* Never let anything with uninheritable virtuals
3817 make it through without complaint. */
3821 {
3823 auto_diagnostic_group d;
3827 field);
3832 field);
3834 {
3838 }
3839 }
3840 else
3841 {
3854 }
3863 }
3868 /* `build_class_init_list' does not recognize
3869 non-FIELD_DECLs. */
3873 }
3875 /* Check the data members (both static and non-static), class-scoped
3876 typedefs, etc., appearing in the declaration of T. Issue
3877 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3878 declaration order) of access declarations; each TREE_VALUE in this
3879 list is a USING_DECL.
3881 In addition, set the following flags:
3883 EMPTY_P
3884 The class is empty, i.e., contains no non-static data members.
3886 CANT_HAVE_CONST_CTOR_P
3887 This class cannot have an implicitly generated copy constructor
3888 taking a const reference.
3890 CANT_HAVE_CONST_ASN_REF
3891 This class cannot have an implicitly generated assignment
3892 operator taking a const reference.
3894 All of these flags should be initialized before calling this
3895 function. */
3897 static void
3901 {
3904 /* Assume there are no access declarations. */
3906 /* Effective C has things to say about classes with pointer members. */
3908 /* Default initialized members affect the whole class. */
3910 /* Lack of any non-static data member of non-volatile literal
3911 type affects a union. */
3913 /* Standard layout requires all FIELDS have same access. */
3917 {
3921 {
3926 /* Save the access declarations for our caller. */
3935 /* FIXME: We should fold in the checking from check_methods. */
3945 {
3946 /* [class.union]
3948 (C++98) If a union contains a static data member,
3949 ... the program is ill-formed. */
3953 }
3958 {
3959 /* [class.union]
3961 If a union contains ... or a [non-static data] member
3962 of reference type, the program is ill-formed. */
3966 }
3968 data_member:
3969 /* Common VAR_DECL & FIELD_DECL processing. */
3973 /* Template instantiation can cause this. Perhaps this
3974 should be a specific instantiation check? */
3976 {
3980 }
3982 {
3986 }
3989 }
3997 /* If it is not a union and at least one non-static data member is
3998 non-literal, the whole class becomes non-literal. Per Core/1453,
3999 volatile non-static data members and base classes are also not allowed.
4000 If it is a union, we might set CLASSTYPE_LITERAL_P after we've seen all
4001 members.
4002 Note: if the type is incomplete we will complain later on. */
4004 {
4007 else
4009 }
4014 {
4015 /* A standard-layout class is a class that:
4017 ... has the same access control (Clause 11) for all
4018 non-static data members, */
4021 else
4024 /* Aggregates must be public. */
4027 }
4029 /* If this is of reference type, check if it needs an init. */
4031 {
4037 {
4038 /* ARM $12.6.2: [A member initializer list] (or, for an
4039 aggregate, initialization by a brace-enclosed list) is the
4040 only way to initialize non-static const and reference
4041 members. */
4044 }
4045 }
4050 {
4052 {
4054 "ignoring packed attribute because of"
4057 }
4061 }
4065 /* We don't treat zero-width bitfields as making a class
4066 non-empty. */
4067 ;
4070 /* Empty data members also don't make a class non-empty. */
4072 else
4073 {
4074 /* The class is non-empty. */
4076 /* The class is not even nearly empty. */
4078 /* If one of the data members contains an empty class, so
4079 does T. */
4083 }
4085 /* This is used by -Weffc++ (see below). Warn only for pointers
4086 to members which might hold dynamic memory. So do not warn
4087 for pointers to functions or pointers to members. */
4093 {
4098 }
4104 {
4111 }
4114 /* DR 148 now allows pointers to members (which are POD themselves),
4115 to be allowed in POD structs. */
4119 /* A potentially-overlapping non-static data member makes the class
4120 non-layout-POD. */
4129 /* We set DECL_C_BIT_FIELD in grokbitfield.
4130 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
4136 {
4139 {
4140 auto_diagnostic_group d;
4144 default_init_member);
4145 }
4147 }
4149 /* Now that we've removed bit-field widths from DECL_INITIAL,
4150 anything left in DECL_INITIAL is an NSDMI that makes the class
4151 non-aggregate in C++11, and non-layout-POD always. */
4153 {
4156 else
4158 }
4161 {
4162 /* If any field is const, the structure type is pseudo-const. */
4167 {
4168 /* ARM $12.6.2: [A member initializer list] (or, for an
4169 aggregate, initialization by a brace-enclosed list) is the
4170 only way to initialize non-static const and reference
4171 members. */
4174 }
4175 }
4176 /* A field that is pseudo-const makes the structure likewise. */
4178 {
4183 }
4185 /* Core issue 80: A non-static data member is required to have a
4186 different name from the class iff the class has a
4187 user-declared constructor. */
4192 }
4194 /* Per CWG 2096, a type is a literal type if it is a union, and at least
4195 one of its non-static data members is of non-volatile literal type. */
4199 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
4200 it should also define a copy constructor and an assignment operator to
4201 implement the correct copy semantic (deep vs shallow, etc.). As it is
4202 not feasible to check whether the constructors do allocate dynamic memory
4203 and store it within members, we approximate the warning like this:
4205 -- Warn only if there are members which are pointers
4206 -- Warn only if there is a non-trivial constructor (otherwise,
4207 there cannot be memory allocated).
4208 -- Warn only if there is a non-trivial destructor. We assume that the
4209 user at least implemented the cleanup correctly, and a destructor
4210 is needed to free dynamic memory.
4212 This seems enough for practical purposes. */
4214 && pointer_member
4218 {
4219 auto_diagnostic_group d;
4221 {
4223 {
4228 }
4234 }
4235 }
4237 /* Non-static data member initializers make the default constructor
4238 non-trivial. */
4240 {
4243 }
4245 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
4249 /* Check anonymous struct/anonymous union fields. */
4252 /* We've built up the list of access declarations in reverse order.
4253 Fix that now. */
4255 }
4257 /* If TYPE is an empty class type, records its OFFSET in the table of
4258 OFFSETS. */
4260 static int
4262 {
4263 splay_tree_node n;
4268 /* Record the location of this empty object in OFFSETS. */
4276 type,
4280 }
4282 /* Returns nonzero if TYPE is an empty class type and there is
4283 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
4285 static int
4287 {
4288 splay_tree_node n;
4289 tree t;
4294 /* Record the location of this empty object in OFFSETS. */
4304 {
4312 {
4316 }
4317 }
4320 {
4325 }
4328 }
4330 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
4331 F for every subobject, passing it the type, offset, and table of
4332 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
4333 be traversed.
4335 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
4336 than MAX_OFFSET will not be walked.
4338 If F returns a nonzero value, the traversal ceases, and that value
4339 is returned. Otherwise, returns zero. */
4341 static int
4343 subobject_offset_fn f,
4344 tree offset,
4345 splay_tree offsets,
4346 tree max_offset,
4348 {
4352 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
4353 stop. */
4361 {
4364 }
4367 {
4368 tree field;
4369 tree binfo;
4372 /* Avoid recursing into objects that are not interesting. */
4376 /* Record the location of TYPE. */
4381 /* Iterate through the direct base classes of TYPE. */
4385 {
4386 tree binfo_offset;
4391 tree orig_binfo;
4392 /* We cannot rely on BINFO_OFFSET being set for the base
4393 class yet, but the offsets for direct non-virtual
4394 bases can be calculated by going back to the TYPE. */
4397 offset,
4401 f,
4402 binfo_offset,
4403 offsets,
4404 max_offset,
4408 }
4411 {
4415 /* Iterate through the virtual base classes of TYPE. In G++
4416 3.2, we included virtual bases in the direct base class
4417 loop above, which results in incorrect results; the
4418 correct offsets for virtual bases are only known when
4419 working with the most derived type. */
4423 {
4425 f,
4427 offset,
4429 offsets,
4430 max_offset,
4434 }
4435 else
4436 {
4437 /* We still have to walk the primary base, if it is
4438 virtual. (If it is non-virtual, then it was walked
4439 above.) */
4445 {
4446 r = (walk_subobject_offsets
4451 }
4452 }
4453 }
4455 /* Iterate through the fields of TYPE. */
4460 {
4461 tree field_offset;
4466 f,
4468 offset,
4469 field_offset),
4470 offsets,
4471 max_offset,
4475 }
4476 }
4478 {
4481 tree index;
4483 /* Avoid recursing into objects that are not interesting. */
4486 || !domain
4490 /* Step through each of the elements in the array. */
4494 {
4496 f,
4497 offset,
4498 offsets,
4499 max_offset,
4505 /* If this new OFFSET is bigger than the MAX_OFFSET, then
4506 there's no point in iterating through the remaining
4507 elements of the array. */
4510 }
4511 }
4514 }
4516 /* Return true iff FIELD_DECL DECL is potentially overlapping. */
4518 static bool
4520 {
4521 /* Base fields are actually potentially overlapping, but C++ bases go through
4522 a different code path based on binfos, and ObjC++ base fields are laid out
4523 in objc-act, so we don't want layout_class_type to mess with them. */
4525 {
4528 }
4532 }
4534 /* Return true iff DECL is an empty field, either for an empty base or a
4535 [[no_unique_address]] data member. */
4537 bool
4539 {
4547 /* Empty fields should have size zero. */
4551 }
4553 /* Record all of the empty subobjects of DECL_OR_BINFO. */
4555 static void
4557 splay_tree offsets)
4558 {
4563 {
4569 }
4570 else
4571 {
4576 }
4578 tree max_offset;
4579 /* If recording subobjects for a non-static data member or a
4580 non-empty base class, we do not need to record offsets beyond
4581 the size of the biggest empty class. Additional data members
4582 will go at the end of the class. Additional base classes will go
4583 either at offset zero (if empty, in which case they cannot
4584 overlap with offsets past the size of the biggest empty class) or
4585 at the end of the class.
4587 However, if we are placing an empty base class, then we must record
4588 all offsets, as either the empty class is at offset zero (where
4589 other empty classes might later be placed) or at the end of the
4590 class (where other objects might then be placed, so other empty
4591 subobjects might later overlap). */
4595 else
4599 }
4601 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4602 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4603 virtual bases of TYPE are examined. */
4605 static int
4607 tree offset,
4608 splay_tree offsets,
4610 {
4611 splay_tree_node max_node;
4613 /* Get the node in OFFSETS that indicates the maximum offset where
4614 an empty subobject is located. */
4616 /* If there aren't any empty subobjects, then there's no point in
4617 performing this check. */
4623 vbases_p);
4624 }
4626 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4627 non-static data member of the type indicated by RLI. BINFO is the
4628 binfo corresponding to the base subobject, OFFSETS maps offsets to
4629 types already located at those offsets. This function determines
4630 the position of the DECL. */
4632 static void
4634 tree decl,
4635 tree binfo,
4636 splay_tree offsets)
4637 {
4640 tree type;
4643 {
4644 /* For the purposes of determining layout conflicts, we want to
4645 use the class type of BINFO; TREE_TYPE (DECL) will be the
4646 CLASSTYPE_AS_BASE version, which does not contain entries for
4647 zero-sized bases. */
4650 }
4651 else
4652 {
4655 }
4657 /* Try to place the field. It may take more than one try if we have
4658 a hard time placing the field without putting two objects of the
4659 same type at the same address. */
4661 {
4664 /* Place this field. */
4668 /* We have to check to see whether or not there is already
4669 something of the same type at the offset we're about to use.
4670 For example, consider:
4672 struct S {};
4673 struct T : public S { int i; };
4674 struct U : public S, public T {};
4676 Here, we put S at offset zero in U. Then, we can't put T at
4677 offset zero -- its S component would be at the same address
4678 as the S we already allocated. So, we have to skip ahead.
4679 Since all data members, including those whose type is an
4680 empty class, have nonzero size, any overlap can happen only
4681 with a direct or indirect base-class -- it can't happen with
4682 a data member. */
4683 /* In a union, overlap is permitted; all members are placed at
4684 offset zero. */
4689 {
4690 /* Strip off the size allocated to this field. That puts us
4691 at the first place we could have put the field with
4692 proper alignment. */
4695 /* Bump up by the alignment required for the type. */
4696 rli->bitpos
4702 }
4705 {
4706 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4707 the offset wasn't aligned like a pointer when we started to
4708 layout this field, that affects its position. */
4711 {
4714 "alignment of %qD increased in %<-fabi-version=9%> "
4716 else
4719 decl);
4720 }
4722 }
4723 else
4724 /* There was no conflict. We're done laying out this field. */
4726 }
4728 /* Now that we know where it will be placed, update its
4729 BINFO_OFFSET. */
4731 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4732 this point because their BINFO_OFFSET is copied from another
4733 hierarchy. Therefore, we may not need to add the entire
4734 OFFSET. */
4740 }
4742 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4744 static int
4746 tree offset,
4748 {
4750 }
4752 /* Layout the empty base BINFO. EOC indicates the byte currently just
4753 past the end of the class, and should be correctly aligned for a
4754 class of the type indicated by BINFO; OFFSETS gives the offsets of
4755 the empty bases allocated so far. T is the most derived
4756 type. Return nonzero iff we added it at the end. */
4758 static bool
4760 splay_tree offsets)
4761 {
4762 tree alignment;
4766 tree type;
4768 {
4771 }
4772 else
4773 {
4776 }
4778 /* On some platforms (ARM), even empty classes will not be
4779 byte-aligned. */
4784 /* This routine should only be used for empty classes. */
4789 else
4792 /* This is an empty base class. We first try to put it at offset
4793 zero. */
4797 offset,
4798 offsets,
4800 {
4801 /* That didn't work. Now, we move forward from the next
4802 available spot in the class. */
4806 {
4808 offset,
4809 offsets,
4811 /* We finally found a spot where there's no overlap. */
4814 /* There's overlap here, too. Bump along to the next spot. */
4816 }
4817 }
4820 {
4825 }
4827 {
4832 }
4835 /* Adjust BINFO_OFFSET (binfo) to be exactly OFFSET. */
4838 else
4839 {
4843 }
4846 }
4848 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4849 fields at NEXT_FIELD, and return it. */
4851 static tree
4853 {
4854 /* Create the FIELD_DECL. */
4864 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4866 else
4867 {
4870 }
4881 /* Add the new FIELD_DECL to the list of fields for T. */
4887 }
4889 /* Layout the base given by BINFO in the class indicated by RLI.
4890 *BASE_ALIGN is a running maximum of the alignments of
4891 any base class. OFFSETS gives the location of empty base
4892 subobjects. T is the most derived type. Return nonzero if the new
4893 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4894 *NEXT_FIELD, unless BINFO is for an empty base class.
4896 Returns the location at which the next field should be inserted. */
4901 {
4906 /* This error is now reported in xref_tag, thus giving better
4907 location information. */
4910 /* Place the base class. */
4912 {
4913 tree decl;
4915 /* The containing class is non-empty because it has a non-empty
4916 base class. */
4919 /* Create the FIELD_DECL. */
4922 /* Try to place the field. It may take more than one try if we
4923 have a hard time placing the field without putting two
4924 objects of the same type at the same address. */
4926 }
4927 else
4928 {
4930 /* A nearly-empty class "has no proper base class that is empty,
4931 not morally virtual, and at an offset other than zero." */
4933 {
4936 /* The check above (used in G++ 3.2) is insufficient because
4937 an empty class placed at offset zero might itself have an
4938 empty base at a nonzero offset. */
4940 empty_base_at_nonzero_offset_p,
4941 size_zero_node,
4946 }
4948 /* We used to not create a FIELD_DECL for empty base classes because of
4949 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4950 be a problem anymore. We need them to handle initialization of C++17
4951 aggregate bases. */
4953 {
4959 }
4961 /* An empty virtual base causes a class to be non-empty
4962 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4963 here because that was already done when the virtual table
4964 pointer was created. */
4965 }
4967 /* Record the offsets of BINFO and its base subobjects. */
4971 }
4973 /* Layout all of the non-virtual base classes. Record empty
4974 subobjects in OFFSETS. T is the most derived type. Return nonzero
4975 if the type cannot be nearly empty. The fields created
4976 corresponding to the base classes will be inserted at
4977 *NEXT_FIELD. */
4979 static void
4982 {
4983 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4984 subobjects. */
4989 /* The primary base class is always allocated first. */
4992 {
4993 /* We need to walk BINFO_BASE_BINFO to find the access of the primary
4994 base, if it is direct. Indirect base fields are private. */
4997 {
5000 {
5003 }
5004 }
5006 primary_access,
5008 }
5010 /* Now allocate the rest of the bases. */
5012 {
5015 /* The primary base was already allocated above, so we don't
5016 need to allocate it again here. */
5020 /* Virtual bases are added at the end (a primary virtual base
5021 will have already been added). */
5028 }
5029 }
5031 /* Go through the TYPE_FIELDS of T issuing any appropriate
5032 diagnostics, figuring out which methods override which other
5033 methods, and so forth. */
5035 static void
5037 {
5040 {
5046 /* The name of the field is the original field name
5047 Save this in auxiliary field for later overloading. */
5049 {
5053 }
5059 "%<transaction_safe_dynamic%> may only be specified for "
5061 }
5063 /* Check whether the eligible special member functions (P0848) are
5064 user-provided. add_method arranged that the CLASSTYPE_MEMBER_VEC only
5065 has the eligible ones, unless none are eligible; TYPE_FIELDS also contains
5066 ineligible overloads, which is why this needs to be separate from the loop
5067 above. */
5070 {
5072 {
5073 /* P0848: At the end of the definition of a class, overload
5074 resolution is performed among the prospective destructors declared
5075 in that class with an empty argument list to select the destructor
5076 for the class, also known as the selected destructor. The program
5077 is ill-formed if overload resolution fails. */
5084 auto_diagnostic_group d;
5087 else
5091 /* Arbitrarily prune the overload set to a single function for
5092 sake of error recovery. */
5095 }
5098 }
5101 {
5112 }
5115 {
5126 }
5127 }
5129 /* FN is constructor, destructor or operator function. Clone the
5130 declaration to create a NAME'd variant. NEED_VTT_PARM_P and
5131 OMIT_INHERITED_PARMS_P are relevant if it's a cdtor. */
5133 static tree
5136 {
5137 /* Copy the function. */
5139 /* Reset the function name. */
5143 /* Clone constraints. */
5148 /* There's no pending inline data for this function. */
5153 {
5154 /* The base-class destructor is not virtual. */
5157 }
5159 {
5160 /* Set the operator code. */
5164 /* The operator could be virtual. */
5167 }
5172 /* If there was an in-charge parameter, drop it from the function
5173 type. */
5175 {
5178 /* Skip the `this' parameter. */
5180 /* Skip the in-charge parameter. */
5182 /* And the VTT parm, in a complete [cd]tor. */
5186 {
5187 /* If we're omitting inherited parms, that just leaves the VTT. */
5190 }
5194 parmtypes);
5200 }
5202 /* Copy the function parameters. */
5205 /* Remove the in-charge parameter. */
5207 {
5211 }
5213 /* And the VTT parm, in a complete [cd]tor. */
5215 {
5218 else
5219 {
5223 }
5224 }
5226 /* A base constructor inheriting from a virtual base doesn't get the
5227 arguments. */
5232 {
5235 }
5237 /* Create the RTL for this function. */
5240 /* Regardless of the current scope, this is a member function, so
5241 not at namespace scope. */
5245 }
5247 /* FN is an operator function, create a variant for CODE. */
5249 tree
5251 {
5254 }
5256 /* FN is a constructor or destructor. Clone the declaration to create
5257 a specialized in-charge or not-in-charge version, as indicated by
5258 NAME. */
5260 static tree
5263 {
5264 tree clone;
5266 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
5268 {
5280 }
5281 else
5282 {
5288 }
5290 /* Remember where this function came from. */
5293 /* Make it easy to find the CLONE given the FN. Note the
5294 template_result of a template will be chained this way too. */
5299 }
5301 /* Build the clones of FN, return the number of clones built. These
5302 will be inserted onto DECL_CHAIN of FN. */
5304 void
5307 {
5311 {
5312 /* For each constructor, we need two variants: an in-charge version
5313 and a not-in-charge version. */
5316 base_omits_inherited_p);
5318 }
5319 else
5320 {
5323 /* For each destructor, we need three variants: an in-charge
5324 version, a not-in-charge version, and an in-charge deleting
5325 version. We clone the deleting version first because that
5326 means it will go second on the TYPE_FIELDS list -- and that
5327 corresponds to the correct layout order in the virtual
5328 function table.
5330 For a non-virtual destructor, we do not build a deleting
5331 destructor. */
5333 {
5335 count++;
5336 }
5340 }
5342 /* The original is now an abstract function that is never
5343 emitted. */
5348 {
5351 }
5352 }
5354 /* Produce declarations for all appropriate clones of FN. If
5355 UPDATE_METHODS is true, the clones are added to the
5356 CLASSTYPE_MEMBER_VEC. */
5358 void
5360 {
5361 /* Avoid inappropriate cloning. */
5366 /* Base cdtors need a vtt parm if there are virtual bases. */
5369 /* Base ctor omits inherited parms it needs a vttparm and inherited
5370 from a virtual nase ctor. */
5375 }
5377 /* DECL is an in charge constructor, which is being defined. This will
5378 have had an in class declaration, from whence clones were
5379 declared. An out-of-class definition can specify additional default
5380 arguments. As it is the clones that are involved in overload
5381 resolution, we must propagate the information from the DECL to its
5382 clones. */
5384 void
5386 {
5387 tree clone;
5391 {
5396 /* Skip the 'this' parameter. */
5412 {
5414 {
5418 }
5424 {
5425 /* A default parameter has been added. Adjust the
5426 clone's parameters. */
5430 {
5433 clone_parms);
5435 }
5438 tree type
5441 clone_parms);
5449 }
5450 }
5452 }
5453 }
5455 /* For each of the constructors and destructors in T, create an
5456 in-charge and not-in-charge variant. */
5458 static void
5460 {
5461 /* We do not need to propagate the usingness to the clone, at this
5462 point that is not needed. */
5468 }
5470 /* Deduce noexcept for a destructor DTOR. */
5472 void
5474 {
5477 noexcept_deferred_spec);
5478 }
5480 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
5481 of TYPE for virtual functions which FNDECL overrides. Return a
5482 mask of the tm attributes found therein. */
5484 static int
5486 {
5488 tree base_binfo;
5492 {
5500 {
5504 else
5507 }
5508 else
5510 }
5513 }
5515 /* Subroutine of set_method_tm_attributes. Handle the checks and
5516 inheritance for one virtual method FNDECL. */
5518 static void
5520 {
5521 tree tm_attr;
5526 /* If FNDECL doesn't actually override anything (i.e. T is the
5527 class that first declares FNDECL virtual), then we're done. */
5534 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
5535 tm_pure must match exactly, otherwise no weakening of
5536 tm_safe > tm_callable > nothing. */
5537 /* ??? The tm_pure attribute didn't make the transition to the
5538 multivendor language spec. */
5540 {
5542 {
5545 }
5546 }
5547 /* If the overridden function is tm_pure, then FNDECL must be. */
5550 /* Look for base class combinations that cannot be satisfied. */
5552 {
5558 }
5559 /* If FNDECL did not declare an attribute, then inherit the most
5560 restrictive one. */
5562 {
5564 }
5565 /* Otherwise validate that we're not weaker than a function
5566 that is being overridden. */
5567 else
5568 {
5572 }
5575 err_override:
5579 }
5581 /* For each of the methods in T, propagate a class-level tm attribute. */
5583 static void
5585 {
5588 /* Don't bother collecting tm attributes if transactional memory
5589 support is not enabled. */
5593 /* Process virtual methods first, as they inherit directly from the
5594 base virtual function and also require validation of new attributes. */
5596 {
5597 tree vchain;
5600 {
5605 }
5606 }
5608 /* If the class doesn't have an attribute, nothing more to do. */
5613 /* Any method that does not yet have a tm attribute inherits
5614 the one from the class. */
5619 }
5621 /* Returns true if FN is a default constructor. */
5623 bool
5625 {
5628 }
5630 /* Returns true iff class T has a user-provided constructor that can be called
5631 with more than zero arguments. */
5633 bool
5635 {
5640 {
5646 }
5649 }
5651 /* Returns the defaulted constructor if T has one. Otherwise, returns
5652 NULL_TREE. */
5654 tree
5656 {
5661 {
5667 }
5670 }
5672 /* Returns true iff FN is a user-provided function, i.e. user-declared
5673 and not defaulted at its first declaration. */
5675 bool
5677 {
5682 }
5684 /* Returns true iff class T has a user-provided constructor. */
5686 bool
5688 {
5700 }
5702 /* Returns true iff class T has a user-provided or explicit constructor. */
5704 bool
5706 {
5714 {
5718 }
5721 }
5723 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5724 declared or explicitly defaulted in the class body) default
5725 constructor. */
5727 bool
5729 {
5736 {
5742 }
5745 }
5747 /* TYPE is being used as a virtual base, and has a non-trivial move
5748 assignment. Return true if this is due to there being a user-provided
5749 move assignment in TYPE or one of its subobjects; if there isn't, then
5750 multiple move assignment can't cause any harm. */
5752 bool
5754 {
5755 /* Does the type itself have a user-provided move assignment operator? */
5763 /* Do any of its bases? */
5765 tree base_binfo;
5770 /* Or non-static data members? */
5772 {
5777 }
5779 /* Seems not. */
5781 }
5783 /* If default-initialization leaves part of TYPE uninitialized, returns
5784 a DECL for the field or TYPE itself (DR 253). */
5786 tree
5788 {
5799 {
5803 }
5807 {
5811 }
5814 }
5816 /* Returns true iff for class T, a trivial synthesized default constructor
5817 would be constexpr. */
5819 bool
5821 {
5822 /* A defaulted trivial default constructor is constexpr
5823 if there is nothing to initialize. */
5825 /* A class with a vptr doesn't have a trivial default ctor.
5826 In C++20, a class can have transient uninitialized members, e.g.:
5828 struct S { int i; constexpr S() = default; };
5830 should work. */
5833 }
5835 /* Returns true iff class T has a constexpr default constructor. */
5837 bool
5839 {
5840 tree fns;
5843 {
5844 /* The caller should have stripped an enclosing array. */
5847 }
5849 {
5852 /* Non-trivial, we need to check subobject constructors. */
5854 }
5857 }
5859 /* Returns true iff class T has a constexpr default constructor or has an
5860 implicitly declared default constructor that we can't tell if it's constexpr
5861 without forcing a lazy declaration (which might cause undesired
5862 instantiations). */
5864 static bool
5866 {
5869 /* Assume it's constexpr. */
5872 }
5874 /* Returns true iff class T has a constexpr destructor. */
5876 bool
5878 {
5879 tree fns;
5882 /* Non-trivial, we need to check subobject destructors. */
5886 }
5888 /* Returns true iff class T has a constexpr destructor or has an
5889 implicitly declared destructor that we can't tell if it's constexpr
5890 without forcing a lazy declaration (which might cause undesired
5891 instantiations). */
5893 static bool
5895 {
5896 /* Until C++20, only trivial destruction is constexpr. */
5902 /* Assume it's constexpr. */
5906 }
5908 /* Returns true iff class TYPE has a virtual destructor. */
5910 bool
5912 {
5913 tree dtor;
5921 }
5923 /* True iff class TYPE has a non-deleted trivial default
5924 constructor. */
5926 bool
5928 {
5930 }
5932 /* Returns true iff T, a class, has a move-assignment or
5933 move-constructor. Does not lazily declare either.
5934 If USER_P is false, any move function will do. If it is true, the
5935 move function must be user-declared.
5937 Note that user-declared here is different from "user-provided",
5938 which doesn't include functions that are defaulted in the
5939 class. */
5941 bool
5943 {
5963 }
5965 /* True iff T has a move constructor that is not deleted. */
5967 bool
5969 {
5976 }
5978 /* If T, a class, has a user-provided copy constructor, copy assignment
5979 operator, or destructor, returns that function. Otherwise, null. */
5981 tree
5983 {
5986 {
5990 }
5996 {
6001 }
6004 {
6008 }
6011 }
6013 /* True iff T has a member or friend declaration of operator OP. */
6015 bool
6017 {
6025 }
6028 /* If T has a defaulted member or friend declaration of OP, return it. */
6030 tree
6032 {
6035 {
6039 }
6043 {
6047 }
6049 }
6051 /* Nonzero if we need to build up a constructor call when initializing an
6052 object of this class, either because it has a user-declared constructor
6053 or because it doesn't have a default constructor (so we need to give an
6054 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
6055 what you care about is whether or not an object can be produced by a
6056 constructor (e.g. so we don't set TREE_READONLY on const variables of
6057 such type); use this function when what you care about is whether or not
6058 to try to call a constructor to create an object. The latter case is
6059 the former plus some cases of constructors that cannot be called. */
6061 bool
6063 {
6064 tree inner;
6074 /* A user-declared constructor might be private, and a constructor might
6075 be trivial but deleted. */
6078 {
6085 }
6087 }
6089 /* Like type_build_ctor_call, but for destructors. */
6091 bool
6093 {
6094 tree inner;
6103 /* A user-declared destructor might be private, and a destructor might
6104 be trivial but deleted. */
6107 {
6114 }
6116 }
6118 /* Returns TRUE iff we need a cookie when dynamically allocating an
6119 array whose elements have the indicated class TYPE. */
6121 static bool
6123 {
6124 tree fns;
6129 /* If there's a non-trivial destructor, we need a cookie. In order
6130 to iterate through the array calling the destructor for each
6131 element, we'll have to know how many elements there are. */
6135 /* If the usual deallocation function is a two-argument whose second
6136 argument is of type `size_t', then we have to pass the size of
6137 the array to the deallocation function, so we will need to store
6138 a cookie. */
6142 /* If there are no `operator []' members, or the lookup is
6143 ambiguous, then we don't need a cookie. */
6146 /* Loop through all of the functions. */
6148 {
6151 /* See if this function is a one-argument delete function. If
6152 it is, then it will be the usual deallocation function. */
6156 /* Do not consider this function if its second argument is an
6157 ellipsis. */
6160 /* Otherwise, if we have a two-argument function and the second
6161 argument is `size_t', it will be the usual deallocation
6162 function -- unless there is one-argument function, too. */
6166 }
6169 }
6171 /* Finish computing the `literal type' property of class type T.
6173 At this point, we have already processed base classes and
6174 non-static data members. We need to check whether the copy
6175 constructor is trivial, the destructor is trivial, and there
6176 is a trivial default constructor or at least one constexpr
6177 constructor other than the copy constructor. */
6179 static void
6181 {
6182 tree fn;
6196 /* C++14 DR 1684 removed this restriction. */
6204 {
6207 {
6208 auto_diagnostic_group d;
6210 "enclosing class of %<constexpr%> non-static "
6213 }
6214 }
6215 }
6217 /* T is a non-literal type used in a context which requires a constant
6218 expression. Explain why it isn't literal. */
6220 void
6222 {
6232 /* Already explained. */
6235 auto_diagnostic_group d;
6239 " %qT is a closure type, which is only literal in "
6246 t);
6251 {
6253 " %q+T is not an aggregate, does not have a trivial "
6254 "default constructor, and has no %<constexpr%> constructor that "
6257 /* Note that we can't simply call locate_ctor because when the
6258 constructor is deleted it just returns NULL_TREE. */
6260 {
6267 {
6270 else
6273 }
6274 }
6275 }
6276 else
6277 {
6281 {
6284 {
6290 }
6291 }
6293 {
6294 tree ftype;
6299 {
6302 field);
6305 }
6309 }
6310 }
6311 }
6313 /* Check the validity of the bases and members declared in T. Add any
6314 implicitly-generated functions (like copy-constructors and
6315 assignment operators). Compute various flag bits (like
6316 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
6317 level: i.e., independently of the ABI in use. */
6319 static void
6321 {
6322 /* Nonzero if the implicitly generated copy constructor should take
6323 a non-const reference argument. */
6325 /* Nonzero if the implicitly generated assignment operator
6326 should take a non-const reference argument. */
6328 tree access_decls;
6331 tree fn;
6333 /* By default, we use const reference arguments and generate default
6334 constructors. */
6338 /* Check all the base-classes and set FMEM members to point to arrays
6339 of potential interest. */
6342 /* Deduce noexcept on destructor. This needs to happen after we've set
6343 triviality flags appropriately for our bases, and before checking
6344 overriden virtual functions via check_methods. */
6350 /* Check all the method declarations. */
6353 /* Save the initial values of these flags which only indicate whether
6354 or not the class has user-provided functions. As we analyze the
6355 bases and members we can set these flags for other reasons. */
6359 /* Check all the data member declarations. We cannot call
6360 check_field_decls until we have called check_bases check_methods,
6361 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
6362 being set appropriately. */
6367 /* A nearly-empty class has to be vptr-containing; a nearly empty
6368 class contains just a vptr. */
6372 /* Do some bookkeeping that will guide the generation of implicitly
6373 declared member functions. */
6376 /* We need to call a constructor for this class if it has a
6377 user-provided constructor, or if the default constructor is going
6378 to initialize the vptr. (This is not an if-and-only-if;
6379 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
6380 themselves need constructing.) */
6383 /* [dcl.init.aggr]
6385 An aggregate is an array or a class with no user-provided
6386 constructors ... and no virtual functions.
6388 Again, other conditions for being an aggregate are checked
6389 elsewhere. */
6395 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
6396 retain the old definition internally for ABI reasons. */
6405 /* Is this class non-layout-POD because it wasn't an aggregate in C++98? */
6407 {
6409 /* It's non-POD for another reason. */
6413 }
6415 /* If the only explicitly declared default constructor is user-provided,
6416 set TYPE_HAS_COMPLEX_DFLT. */
6422 /* Warn if a public base of a polymorphic type has an accessible
6423 non-virtual destructor. It is only now that we know the class is
6424 polymorphic. Although a polymorphic base will have a already
6425 been diagnosed during its definition, we warn on use too. */
6427 {
6430 tree base_binfo;
6434 {
6442 basetype);
6443 }
6444 }
6446 /* If the class has no user-declared constructor, but does have
6447 non-static const or reference data members that can never be
6448 initialized, issue a warning. */
6450 /* Classes with user-declared constructors are presumed to
6451 initialize these members. */
6453 /* Aggregates can be initialized with brace-enclosed
6454 initializers. */
6456 {
6457 tree field;
6460 {
6461 tree type;
6478 }
6479 }
6481 /* Synthesize any needed methods. */
6483 cant_have_const_ctor,
6484 no_const_asn_ref);
6486 /* Check defaulted declarations here so we have cant_have_const_ctor
6487 and don't need to worry about clones. */
6492 /* ...except handle comparisons later, in finish_struct_1. */
6494 {
6495 bool imp_const_p
6499 }
6502 /* "This class type is not an aggregate." */
6505 /* Compute the 'literal type' property before we
6506 do anything with non-static member functions. */
6509 /* Create the in-charge and not-in-charge variants of constructors
6510 and destructors. */
6513 /* Process the using-declarations. */
6517 /* Figure out whether or not we will need a cookie when dynamically
6518 allocating an array of this type. */
6522 /* Classes marked hot or cold propagate the attribute to all members. We
6523 may do this now that methods are declared. This does miss some lazily
6524 declared special member functions (CLASSTYPE_LAZY_*), which are handled
6525 in lazily_declare_fn later on. */
6527 }
6529 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
6530 accordingly. If a new vfield was created (because T doesn't have a
6531 primary base class), then the newly created field is returned. It
6532 is not added to the TYPE_FIELDS list; it is the caller's
6533 responsibility to do that. Accumulate declared virtual functions
6534 on VIRTUALS_P. */
6536 static tree
6538 {
6539 tree fn;
6541 /* Collect the virtual functions declared in T. */
6546 {
6555 }
6557 /* If we couldn't find an appropriate base class, create a new field
6558 here. Even if there weren't any new virtual functions, we might need a
6559 new virtual function table if we're supposed to include vptrs in
6560 all classes that need them. */
6562 {
6563 /* We build this decl with vtbl_ptr_type_node, which is a
6564 `vtable_entry_type*'. It might seem more precise to use
6565 `vtable_entry_type (*)[N]' where N is the number of virtual
6566 functions. However, that would require the vtable pointer in
6567 base classes to have a different type than the vtable pointer
6568 in derived classes. We could make that happen, but that
6569 still wouldn't solve all the problems. In particular, the
6570 type-based alias analysis code would decide that assignments
6571 to the base class vtable pointer can't alias assignments to
6572 the derived class vtable pointer, since they have different
6573 types. Thus, in a derived class destructor, where the base
6574 class constructor was inlined, we could generate bad code for
6575 setting up the vtable pointer.
6577 Therefore, we use one type for all vtable pointers. We still
6578 use a type-correct type; it's just doesn't indicate the array
6579 bounds. That's better than using `void*' or some such; it's
6580 cleaner, and it let's the alias analysis code know that these
6581 stores cannot alias stores to void*! */
6582 tree field;
6595 /* This class is non-empty. */
6599 }
6602 }
6604 /* Add OFFSET to all base types of BINFO which is a base in the
6605 hierarchy dominated by T.
6607 OFFSET, which is a type offset, is number of bytes. */
6609 static void
6611 {
6613 tree primary_binfo;
6614 tree base_binfo;
6616 /* Update BINFO's offset. */
6621 offset));
6623 /* Find the primary base class. */
6629 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
6630 downwards. */
6632 {
6633 /* Don't do the primary base twice. */
6641 }
6642 }
6644 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
6645 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
6646 empty subobjects of T. */
6648 static void
6650 {
6651 tree vbase;
6658 /* Find the last field. The artificial fields created for virtual
6659 bases will go after the last extant field to date. */
6664 /* Go through the virtual bases, allocating space for each virtual
6665 base that is not already a primary base class. These are
6666 allocated in inheritance graph order. */
6668 {
6673 {
6674 /* This virtual base is not a primary base of any class in the
6675 hierarchy, so we have to add space for it. */
6677 access_private_node,
6679 }
6680 }
6681 }
6683 /* Returns the offset of the byte just past the end of the base class
6684 BINFO. */
6686 static tree
6688 {
6689 tree size;
6694 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
6695 allocate some space for it. It cannot have virtual bases, so
6696 TYPE_SIZE_UNIT is fine. */
6698 else
6702 }
6704 /* Returns one of three variations of the ending offset of T. If MODE is
6705 eoc_nvsize, the result is the ABI "nvsize" (i.e. sizeof before allocating
6706 vbases). If MODE is eoc_vsize, the result is the sizeof after allocating
6707 vbases but before rounding, which is not named in the ABI. If MODE is
6708 eoc_nv_or_dsize, the result is the greater of "nvsize" and "dsize" (the size
6709 of the actual data in the class, kinda), as used for allocation of
6710 potentially-overlapping fields. */
6713 static tree
6715 {
6718 tree binfo;
6719 tree base_binfo;
6720 tree offset;
6725 {
6734 }
6739 {
6742 /* DECL_SIZE_UNIT can be null for a flexible array. */
6746 /* For empty fields DECL_SIZE_UNIT is 0, but we want the
6747 size of the type (usually 1) for computing nvsize. */
6751 {
6756 }
6757 else
6761 }
6766 {
6768 /* For dsize, don't count trailing empty bases. */
6771 else
6775 }
6778 }
6780 /* Warn as appropriate about the change in whether we pack into the tail
6781 padding of FIELD, a base field which has a C++14 aggregate type with default
6782 member initializers. */
6784 static void
6786 {
6806 {
6810 "%<-std=c++14%> and up changes in "
6812 else
6814 "%<-std=c++14%> and up changes in "
6816 }
6817 }
6819 /* Warn about bases of T that are inaccessible because they are
6820 ambiguous. For example:
6822 struct S {};
6823 struct T : public S {};
6824 struct U : public S, public T {};
6826 Here, `(S*) new U' is not allowed because there are two `S'
6827 subobjects of U. */
6829 static void
6831 {
6834 tree basetype;
6835 tree binfo;
6836 tree base_binfo;
6838 /* If not checking for warning then return early. */
6842 /* If there are no repeated bases, nothing can be ambiguous. */
6846 /* Check direct bases. */
6849 {
6855 }
6857 /* Check for ambiguous virtual bases. */
6861 {
6867 }
6868 }
6870 /* Compare two INTEGER_CSTs K1 and K2. */
6872 static int
6874 {
6876 }
6878 /* Increase the size indicated in RLI to account for empty classes
6879 that are "off the end" of the class. */
6881 static void
6883 {
6884 tree eoc;
6885 tree rli_size;
6887 /* It might be the case that we grew the class to allocate a
6888 zero-sized base class. That won't be reflected in RLI, yet,
6889 because we are willing to overlay multiple bases at the same
6890 offset. However, now we need to make sure that RLI is big enough
6891 to reflect the entire class. */
6896 {
6897 /* The size should have been rounded to a whole byte. */
6900 rli->bitpos
6909 }
6910 }
6912 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
6913 BINFO_OFFSETs for all of the base-classes. Position the vtable
6914 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
6916 static void
6918 {
6919 tree non_static_data_members;
6920 tree field;
6921 tree vptr;
6922 record_layout_info rli;
6923 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6924 types that appear at that offset. */
6925 splay_tree empty_base_offsets;
6926 /* True if the last field laid out was a bit-field. */
6928 /* The location at which the next field should be inserted. */
6931 /* Keep track of the first non-static data member. */
6934 /* Start laying out the record. */
6937 /* Mark all the primary bases in the hierarchy. */
6940 /* Create a pointer to our virtual function table. */
6943 /* The vptr is always the first thing in the class. */
6945 {
6950 }
6951 else
6954 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6959 /* Layout the non-static data members. */
6961 {
6962 tree type;
6963 tree padding;
6965 /* We still pass things that aren't non-static data members to
6966 the back end, in case it wants to do something with them. */
6968 {
6970 /* If the static data member has incomplete type, keep track
6971 of it so that it can be completed later. (The handling
6972 of pending statics in finish_record_layout is
6973 insufficient; consider:
6975 struct S1;
6976 struct S2 { static S1 s1; };
6978 At this point, finish_record_layout will be called, but
6979 S1 is still incomplete.) */
6981 {
6983 /* The visibility of static data members is determined
6984 at their point of declaration, not their point of
6985 definition. */
6987 }
6989 }
7001 {
7002 /* if D is a potentially-overlapping data member, update sizeof(C) to
7003 max (sizeof(C), offset(D)+max (nvsize(D), dsize(D))). */
7006 else
7007 {
7011 }
7012 }
7014 /* If this field is a bit-field whose width is greater than its
7015 type, then there are some special rules for allocating
7016 it. */
7019 {
7021 /* We must allocate the bits as if suitably aligned for the
7022 longest integer type that fits in this many bits. Then,
7023 we are supposed to use the left over bits as additional
7024 padding. */
7026 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
7034 {
7036 /* Too big, so our current guess is what we want. */
7038 /* Not bigger than limit, ok */
7040 }
7042 /* Figure out how much additional padding is required. */
7044 /* In a union, the padding field must have the full width
7045 of the bit-field; all fields start at offset zero. */
7047 else
7054 /* An unnamed bitfield does not normally affect the
7055 alignment of the containing class on a target where
7056 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
7057 make any exceptions for unnamed bitfields when the
7058 bitfields are longer than their types. Therefore, we
7059 temporarily give the field a name. */
7061 {
7064 }
7070 empty_base_offsets);
7073 /* Now that layout has been performed, set the size of the
7074 field to the size of its declared type; the rest of the
7075 field is effectively invisible. */
7077 /* We must also reset the DECL_MODE of the field. */
7079 }
7081 {
7084 }
7085 else
7087 empty_base_offsets);
7089 /* Remember the location of any empty classes in FIELD. */
7092 /* If a bit-field does not immediately follow another bit-field,
7093 and yet it starts in the middle of a byte, we have failed to
7094 comply with the ABI. */
7097 /* The TREE_NO_WARNING flag gets set by Objective-C when
7098 laying out an Objective-C class. The ObjC ABI differs
7099 from the C++ ABI, and so we do not want a warning
7100 here. */
7102 && !last_field_was_bitfield
7105 bitsize_unit_node)))
7107 "offset of %qD is not ABI-compliant and may "
7110 /* The middle end uses the type of expressions to determine the
7111 possible range of expression values. In order to optimize
7112 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
7113 must be made aware of the width of "i", via its type.
7115 Because C++ does not have integer types of arbitrary width,
7116 we must (for the purposes of the front end) convert from the
7117 type assigned here to the declared type of the bitfield
7118 whenever a bitfield expression is used as an rvalue.
7119 Similarly, when assigning a value to a bitfield, the value
7120 must be converted to the type given the bitfield here. */
7122 {
7127 {
7134 }
7135 }
7137 /* If we needed additional padding after this field, add it
7138 now. */
7140 {
7141 tree padding_field;
7144 FIELD_DECL,
7145 NULL_TREE,
7146 char_type_node);
7154 NULL_TREE,
7155 empty_base_offsets);
7156 }
7159 }
7162 {
7163 /* Make sure that we are on a byte boundary so that the size of
7164 the class without virtual bases will always be a round number
7165 of bytes. */
7168 }
7170 /* We used to remove zero width bitfields at this point since PR42217,
7171 while the C FE never did that. That caused ABI differences on various
7172 targets. Set the DECL_FIELD_CXX_ZERO_WIDTH_BIT_FIELD flag on them
7173 instead, so that the backends can emit -Wpsabi warnings in the cases
7174 where the ABI changed. */
7176 {
7179 /* We should not be confused by the fact that grokbitfield
7180 temporarily sets the width of the bit field into
7181 DECL_BIT_FIELD_REPRESENTATIVE (field).
7182 check_bitfield_decl eventually sets DECL_SIZE (field)
7183 to that width. */
7189 }
7192 {
7193 /* T needs a different layout as a base (eliding virtual bases
7194 or whatever). Create that version. */
7203 /* If the ABI version is not at least two, and the last
7204 field was a bit-field, RLI may not be on a byte
7205 boundary. In particular, rli_size_unit_so_far might
7206 indicate the last complete byte, while rli_size_so_far
7207 indicates the total number of bits used. Therefore,
7208 rli_size_so_far, rather than rli_size_unit_so_far, is
7209 used to compute TYPE_SIZE_UNIT. */
7211 /* Set the size and alignment for the new type. */
7219 eoc);
7231 /* Copy the non-static data members of T. This will include its
7232 direct non-virtual bases & vtable. */
7236 {
7238 /* Zap any NSDMI, it's not needed and might be a deferred
7239 parse. */
7243 }
7246 /* We use the base type for trivial assignments, and hence it
7247 needs a mode. */
7250 /* Record the base version of the type. */
7252 }
7253 else
7256 /* Every empty class contains an empty class. */
7260 /* Set the TYPE_DECL for this type to contain the right
7261 value for DECL_OFFSET, so that we can use it as part
7262 of a COMPONENT_REF for multiple inheritance. */
7265 /* Now fix up any virtual base class types that we left lying
7266 around. We must get these done before we try to lay out the
7267 virtual function table. As a side-effect, this will remove the
7268 base subobject fields. */
7271 /* Make sure that empty classes are reflected in RLI at this
7272 point. */
7275 /* Make sure not to create any structures with zero size. */
7281 /* If this is a non-POD, declaring it packed makes a difference to how it
7282 can be used as a field; don't let finalize_record_size undo it. */
7286 /* Let the back end lay out the type. */
7289 /* If we didn't end up needing an as-base type, don't use it. */
7291 /* If T's CLASSTYPE_AS_BASE is TYPE_USER_ALIGN, but T is not,
7292 replacing the as-base type would change CLASSTYPE_USER_ALIGN,
7293 causing us to lose the user-specified alignment as in PR94050. */
7305 /* Warn about bases that can't be talked about due to ambiguity. */
7308 /* Now that we're done with layout, give the base fields the real types. */
7313 /* Clean up. */
7320 }
7322 /* Determine the "key method" for the class type indicated by TYPE,
7323 and set CLASSTYPE_KEY_METHOD accordingly. */
7325 void
7327 {
7328 tree method;
7335 /* The key method is the first non-pure virtual function that is not
7336 inline at the point of class definition. On some targets the
7337 key function may not be inline; those targets should not call
7338 this function until the end of the translation unit. */
7344 {
7347 }
7350 }
7352 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
7353 class data member of non-zero size, otherwise false. */
7357 {
7365 {
7369 }
7372 }
7374 /* Used by find_flexarrays and related functions. */
7376 struct flexmems_t
7377 {
7378 /* The first flexible array member or non-zero array member found
7379 in the order of layout. */
7380 tree array;
7381 /* First non-static non-empty data member in the class or its bases. */
7382 tree first;
7383 /* The first non-static non-empty data member following either
7384 the flexible array member, if found, or the zero-length array member
7385 otherwise. AFTER[1] refers to the first such data member of a union
7386 of which the struct containing the flexible array member or zero-length
7387 array is a member, or NULL when no such union exists. This element is
7388 only used during searching, not for diagnosing problems. AFTER[0]
7389 refers to the first such data member that is not a member of such
7390 a union. */
7393 /* Refers to a struct (not union) in which the struct of which the flexible
7394 array is member is defined. Used to diagnose strictly (according to C)
7395 invalid uses of the latter structs. */
7396 tree enclosing;
7397 };
7399 /* Find either the first flexible array member or the first zero-length
7400 array, in that order of preference, among members of class T (but not
7401 its base classes), and set members of FMEM accordingly.
7402 BASE_P is true if T is a base class of another class.
7403 PUN is set to the outermost union in which the flexible array member
7404 (or zero-length array) is defined if one such union exists, otherwise
7405 to NULL.
7406 Similarly, PSTR is set to a data member of the outermost struct of
7407 which the flexible array is a member if one such struct exists,
7408 otherwise to NULL. */
7410 static void
7414 {
7415 /* Set the "pointer" to the outermost enclosing union if not set
7416 yet and maintain it for the remainder of the recursion. */
7421 {
7425 /* Is FLD a typedef for an anonymous struct? */
7427 /* FIXME: Note that typedefs (as well as arrays) need to be fully
7428 handled elsewhere so that errors like the following are detected
7429 as well:
7430 typedef struct { int i, a[], j; } S; // bug c++/72753
7431 S s [2]; // bug c++/68489
7432 */
7437 {
7438 /* Check the nested unnamed type referenced via a typedef
7439 independently of FMEM (since it's not a data member of
7440 the enclosing class). */
7443 }
7445 /* Skip anything that's GCC-generated or not a (non-static) data
7446 member. */
7450 /* Type of the member. */
7455 /* Determine the type of the array element or object referenced
7456 by the member so that it can be checked for flexible array
7457 members if it hasn't been yet. */
7464 {
7466 {
7467 /* Once the member after the flexible array has been found
7468 we're done. */
7471 }
7474 {
7475 /* Descend into the non-static member struct or union and try
7476 to find a flexible array member or zero-length array among
7477 its members. This is only necessary for anonymous types
7478 and types in whose context the current type T has not been
7479 defined (the latter must not be checked again because they
7480 are already in the process of being checked by one of the
7481 recursive calls). */
7486 /* If this member isn't anonymous and a prior non-flexible array
7487 member has been seen in one of the enclosing structs, clear
7488 the FIRST member since it doesn't contribute to the flexible
7489 array struct's members. */
7500 {
7501 /* Restore the FIRST member reset above if no flexible
7502 array member has been found in this member's struct. */
7504 }
7506 /* If the member struct contains the first flexible array
7507 member, or if this member is a base class, continue to
7508 the next member and avoid setting the FMEM->NEXT pointer
7509 to point to it. */
7512 }
7513 }
7516 {
7517 /* Remember the first non-static data member. */
7521 /* Remember the first non-static data member after the flexible
7522 array member, if one has been found, or the zero-length array
7523 if it has been found. */
7526 }
7528 /* Skip non-arrays. */
7532 /* Determine the upper bound of the array if it has one. */
7534 {
7536 {
7537 /* Make a record of the zero-length array if either one
7538 such field or a flexible array member has been seen to
7539 handle the pathological and unlikely case of multiple
7540 such members. */
7543 }
7545 {
7546 /* Remember the first zero-length array unless a flexible array
7547 member has already been seen. */
7550 }
7551 }
7552 else
7553 {
7554 /* Flexible array members have no upper bound. */
7556 {
7558 {
7559 /* Replace the zero-length array if it's been stored and
7560 reset the after pointer. */
7564 }
7566 /* Make a record of another flexible array member. */
7568 }
7569 else
7570 {
7573 }
7574 }
7575 }
7576 }
7578 /* Diagnose a strictly (by the C standard) invalid use of a struct with
7579 a flexible array member (or the zero-length array extension). */
7581 static void
7583 {
7585 {
7586 auto_diagnostic_group d;
7597 }
7598 }
7600 /* Issue diagnostics for invalid flexible array members or zero-length
7601 arrays that are not the last elements of the containing class or its
7602 base classes or that are its sole members. */
7604 static void
7606 {
7611 {
7614 }
7616 /* Has a diagnostic been issued? */
7623 {
7630 {
7633 auto_diagnostic_group d;
7635 {
7638 }
7639 }
7640 }
7641 else
7642 {
7650 {
7654 auto_diagnostic_group d;
7657 else
7660 /* In the unlikely event that the member following the flexible
7661 array member is declared in a different class, or the member
7662 overlaps another member of a common union, point to it.
7663 Otherwise it should be obvious. */
7667 {
7672 }
7673 }
7674 }
7678 }
7681 /* Recursively check to make sure that any flexible array or zero-length
7682 array members of class T or its bases are valid (i.e., not the sole
7683 non-static data member of T and, if one exists, that it is the last
7684 non-static data member of T and its base classes. FMEM is expected
7685 to be initially null and is used internally by recursive calls to
7686 the function. Issue the appropriate diagnostics for the array member
7687 that fails the checks. */
7689 static void
7692 {
7693 /* Initialize the result of a search for flexible array and zero-length
7694 array members. Avoid doing any work if the most interesting FMEM data
7695 have already been populated. */
7704 /* Recursively check the primary base class first. */
7706 {
7709 }
7711 /* Recursively check the base classes. */
7714 {
7717 /* The primary base class was already checked above. */
7721 /* Virtual base classes are at the end. */
7725 /* Check the base class. */
7727 }
7730 {
7731 /* Check virtual base classes only once per derived class.
7732 I.e., this check is not performed recursively for base
7733 classes. */
7735 tree base_binfo;
7739 {
7740 /* Check the virtual base class. */
7744 }
7745 }
7747 /* Is the type unnamed (and therefore a member of it potentially
7748 an anonymous struct or union)? */
7753 /* Search the members of the current (possibly derived) class, skipping
7754 unnamed structs and unions since those could be anonymous. */
7759 {
7760 /* Issue diagnostics for invalid flexible and zero-length array
7761 members found in base classes or among the members of the current
7762 class. Ignore anonymous structs and unions whose members are
7763 considered to be members of the enclosing class and thus will
7764 be diagnosed when checking it. */
7766 }
7767 }
7769 /* Perform processing required when the definition of T (a class type)
7770 is complete. Diagnose invalid definitions of flexible array members
7771 and zero-size arrays. */
7773 void
7775 {
7776 tree x;
7777 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
7781 {
7786 }
7788 /* If this type was previously laid out as a forward reference,
7789 make sure we lay it out again. */
7793 /* Make assumptions about the class; we'll reset the flags if
7794 necessary. */
7800 /* Do end-of-class semantic processing: checking the validity of the
7801 bases and members and add implicitly generated methods. */
7804 /* Find the key method. */
7806 {
7807 /* The Itanium C++ ABI permits the key method to be chosen when
7808 the class is defined -- even though the key method so
7809 selected may later turn out to be an inline function. On
7810 some systems (such as ARM Symbian OS) the key method cannot
7811 be determined until the end of the translation unit. On such
7812 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
7813 will cause the class to be added to KEYED_CLASSES. Then, in
7814 finish_file we will determine the key method. */
7818 /* If a polymorphic class has no key method, we may emit the vtable
7819 in every translation unit where the class definition appears. If
7820 we're devirtualizing, we can look into the vtable even if we
7821 aren't emitting it.
7823 Additionally, if the class is attached to a named module, make sure
7824 to always emit the vtable in this TU. */
7827 }
7829 /* Layout the class itself. */
7831 /* COMPLETE_TYPE_P is now true. */
7835 /* With the layout complete, check for flexible array members and
7836 zero-length arrays that might overlap other members in the final
7837 layout. */
7842 /* If necessary, create the primary vtable for this class. */
7844 {
7845 /* We must enter these virtuals into the table. */
7849 /* Here we know enough to change the type of our virtual
7850 function table, but we will wait until later this function. */
7853 /* If we're warning about ABI tags, check the types of the new
7854 virtual functions. */
7858 }
7861 {
7863 tree fn;
7870 /* Add entries for virtual functions introduced by this class. */
7874 /* Set DECL_VINDEX for all functions declared in this class. */
7876 fn;
7878 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
7880 {
7884 /* A thunk. We should never be calling this entry directly
7885 from this vtable -- we'd use the entry for the non
7886 thunk base function. */
7890 }
7891 }
7899 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
7900 for any static member objects of the type we're working on. */
7903 {
7904 /* Synthesize constexpr defaulted comparisons. */
7910 }
7916 /* Complain if one of the field types requires lower visibility. */
7919 /* Make the rtl for any new vtables we have created, and unmark
7920 the base types we marked. */
7923 /* Build the VTT for T. */
7930 "%q#T has virtual functions and accessible"
7938 /* Class layout, assignment of virtual table slots, etc., is now
7939 complete. Give the back end a chance to tweak the visibility of
7940 the class or perform any other required target modifications. */
7950 /* Finish debugging output for this type. */
7954 {
7957 {
7960 }
7962 {
7965 else
7966 {
7969 }
7971 }
7973 {
7975 "the type of the first field has a different ABI from the "
7978 }
7979 }
7980 }
7982 /* When T was built up, the member declarations were added in reverse
7983 order. Rearrange them to declaration order. */
7985 void
7987 {
7988 tree next;
7989 tree prev;
7990 tree x;
7992 /* The following lists are all in reverse order. Put them in
7993 declaration order now. */
7996 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
7997 order, so we can't just use nreverse. Due to stat_hack
7998 chicanery in finish_member_declaration. */
8003 {
8007 }
8010 {
8013 }
8014 }
8016 /* Classes, structs or unions T marked with hotness attributes propagate
8017 the attribute to all methods. */
8019 void
8021 {
8027 tree class_has_cold_attr
8029 tree class_has_hot_attr
8036 }
8038 tree
8040 {
8043 /* Now that we've got all the field declarations, reverse everything
8044 as necessary. */
8050 /* Nadger the current location so that diagnostics point to the start of
8051 the struct, not the end. */
8055 {
8056 tree x;
8060 {
8064 }
8066 {
8069 }
8071 /* Also add a USING_DECL for operator=. We know there'll be (at
8072 least) one, but we don't know the signature(s). We want name
8073 lookup not to fail or recurse into bases. This isn't added
8074 to the template decl list so we drop this at instantiation
8075 time. */
8077 NULL_TREE);
8087 /* COMPLETE_TYPE_P is now true. */
8091 /* We need to emit an error message if this type was used as a parameter
8092 and it is an abstract type, even if it is a template. We construct
8093 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
8094 account and we call complete_vars with this type, which will check
8095 the PARM_DECLS. Note that while the type is being defined,
8096 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
8097 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
8104 /* Remember current #pragma pack value. */
8108 {
8112 }
8116 /* Fix up any variants we've already built. */
8118 }
8119 else
8121 /* COMPLETE_TYPE_P is now true. */
8126 {
8127 /* People keep complaining that the compiler crashes on an invalid
8128 definition of initializer_list, so I guess we should explicitly
8129 reject it. What the compiler internals care about is that it's a
8130 template and has a pointer field followed by size_type field. */
8133 {
8136 {
8140 }
8141 }
8142 /* It also cannot be a union. */
8147 }
8155 else
8167 /* Lambdas are defined by the LAMBDA_EXPR. */
8172 }
8173 \f
8174 /* Hash table to avoid endless recursion when handling references. */
8177 /* Return the dynamic type of INSTANCE, if known.
8178 Used to determine whether the virtual function table is needed
8179 or not.
8181 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
8182 of our knowledge of its type. *NONNULL should be initialized
8183 before this function is called. */
8185 static tree
8187 {
8188 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
8191 {
8195 else
8199 /* This is a call to a constructor, hence it's never zero. */
8202 {
8206 }
8210 /* This is a call to a constructor, hence it's never zero. */
8212 {
8216 }
8225 /* Propagate nonnull. */
8230 CASE_CONVERT:
8236 {
8237 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
8238 with a real object -- given &p->f, p can still be null. */
8240 /* ??? Probably should check DECL_WEAK here. */
8243 }
8247 /* If this component is really a base class reference, then the field
8248 itself isn't definitive. */
8257 {
8261 }
8262 /* fall through. */
8267 {
8271 }
8273 {
8277 /* if we're in a ctor or dtor, we know our type. If
8278 current_class_ptr is set but we aren't in a function, we're in
8279 an NSDMI (and therefore a constructor). */
8284 {
8288 }
8289 }
8291 {
8292 /* We only need one hash table because it is always left empty. */
8294 fixed_type_or_null_ref_ht
8297 /* Reference variables should be references to objects. */
8301 /* Enter the INSTANCE in a table to prevent recursion; a
8302 variable's initializer may refer to the variable
8303 itself. */
8308 {
8309 tree type;
8318 }
8319 }
8325 else
8326 /* TODO: Recursion may be correct for some non-location-wrapper
8327 uses of VIEW_CONVERT_EXPR. */
8332 }
8333 #undef RECUR
8334 }
8336 /* Return nonzero if the dynamic type of INSTANCE is known, and
8337 equivalent to the static type. We also handle the case where
8338 INSTANCE is really a pointer. Return negative if this is a
8339 ctor/dtor. There the dynamic type is known, but this might not be
8340 the most derived base of the original object, and hence virtual
8341 bases may not be laid out according to this type.
8343 Used to determine whether the virtual function table is needed
8344 or not.
8346 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
8347 of our knowledge of its type. *NONNULL should be initialized
8348 before this function is called. */
8350 int
8352 {
8355 tree fixed;
8357 /* processing_template_decl can be false in a template if we're in
8358 instantiate_non_dependent_expr, but we still want to suppress
8359 this check. */
8361 {
8362 /* In a template we only care about the type of the result. */
8366 }
8378 }
8380 \f
8381 void
8383 {
8386 current_class_stack
8393 }
8395 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
8397 static void
8399 {
8400 tree type;
8402 /* We are re-entering the same class we just left, so we don't
8403 have to search the whole inheritance matrix to find all the
8404 decls to bind again. Instead, we install the cached
8405 class_shadowed list and walk through it binding names. */
8408 /* Restore IDENTIFIER_TYPE_VALUE. */
8410 type;
8413 }
8415 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
8416 appropriate for TYPE.
8418 So that we may avoid calls to lookup_name, we cache the _TYPE
8419 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
8421 For multiple inheritance, we perform a two-pass depth-first search
8422 of the type lattice. */
8424 void
8426 {
8427 class_stack_node_t csn;
8431 /* Make sure there is enough room for the new entry on the stack. */
8433 {
8435 current_class_stack
8437 current_class_stack_size);
8438 }
8440 /* Insert a new entry on the class stack. */
8447 current_class_depth++;
8449 /* Now set up the new type. */
8455 /* By default, things in classes are private, while things in
8456 structures or unions are public. */
8458 ? access_private_node
8464 {
8465 /* Forcibly remove any old class remnants. */
8467 }
8473 else
8475 }
8477 /* Get out of the current class scope. If we were in a class scope
8478 previously, that is the one popped to. */
8480 void
8482 {
8485 current_class_depth--;
8491 }
8493 /* Mark the top of the class stack as hidden. */
8495 void
8497 {
8500 }
8502 /* Mark the top of the class stack as un-hidden. */
8504 void
8506 {
8509 }
8511 /* If the class type currently being defined is either T or
8512 a nested type of T, returns the type from the current_class_stack,
8513 which might be equivalent to but not equal to T in case of
8514 constrained partial specializations. */
8516 tree
8518 {
8526 /* We start looking from 1 because entry 0 is from global scope,
8527 and has no type. */
8529 {
8530 tree c;
8533 else
8534 {
8538 }
8543 }
8545 }
8547 /* If either current_class_type or one of its enclosing classes are derived
8548 from T, return the appropriate type. Used to determine how we found
8549 something via unqualified lookup. */
8551 tree
8553 {
8556 /* The bases of a dependent type are unknown. */
8567 {
8572 }
8575 }
8577 /* Return the outermost enclosing class type that is still open, or
8578 NULL_TREE. */
8580 tree
8582 {
8589 {
8596 }
8598 }
8600 /* Returns the innermost class type which is not a lambda closure type. */
8602 tree
8604 {
8609 }
8611 /* When entering a class scope, all enclosing class scopes' names with
8612 static meaning (static variables, static functions, types and
8613 enumerators) have to be visible. This recursive function calls
8614 pushclass for all enclosing class contexts until global or a local
8615 scope is reached. TYPE is the enclosed class. */
8617 void
8619 {
8620 /* A namespace might be passed in error cases, like A::B:C. */
8628 }
8630 /* Undoes a push_nested_class call. */
8632 void
8634 {
8640 }
8642 /* Returns the number of extern "LANG" blocks we are nested within. */
8644 int
8646 {
8648 }
8650 /* Set global variables CURRENT_LANG_NAME to appropriate value
8651 so that behavior of name-mangling machinery is correct. */
8653 void
8655 {
8662 else
8664 }
8666 /* Get out of the current language scope. */
8668 void
8670 {
8672 }
8673 \f
8674 /* Type instantiation routines. */
8676 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
8677 matches the TARGET_TYPE. If there is no satisfactory match, return
8678 error_mark_node, and issue an error & warning messages under
8679 control of FLAGS. Permit pointers to member function if FLAGS
8680 permits. If TEMPLATE_ONLY, the name of the overloaded function was
8681 a template-id, and EXPLICIT_TARGS are the explicitly provided
8682 template arguments.
8684 If OVERLOAD is for one or more member functions, then ACCESS_PATH
8685 is the base path used to reference those member functions. If
8686 the address is resolved to a member function, access checks will be
8687 performed and errors issued if appropriate. */
8689 static tree
8691 tree overload,
8692 tsubst_flags_t complain,
8694 tree explicit_targs,
8695 tree access_path)
8696 {
8697 /* Here's what the standard says:
8699 [over.over]
8701 If the name is a function template, template argument deduction
8702 is done, and if the argument deduction succeeds, the deduced
8703 arguments are used to generate a single template function, which
8704 is added to the set of overloaded functions considered.
8706 Non-member functions and static member functions match targets of
8707 type "pointer-to-function" or "reference-to-function." Nonstatic
8708 member functions match targets of type "pointer-to-member
8709 function;" the function type of the pointer to member is used to
8710 select the member function from the set of overloaded member
8711 functions. If a non-static member function is selected, the
8712 reference to the overloaded function name is required to have the
8713 form of a pointer to member as described in 5.3.1.
8715 If more than one function is selected, any template functions in
8716 the set are eliminated if the set also contains a non-template
8717 function, and any given template function is eliminated if the
8718 set contains a second template function that is more specialized
8719 than the first according to the partial ordering rules 14.5.5.2.
8720 After such eliminations, if any, there shall remain exactly one
8721 selected function. */
8724 /* We store the matches in a TREE_LIST rooted here. The functions
8725 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
8726 interoperability with most_specialized_instantiation. */
8728 tree fn;
8729 tree target_fn_type;
8731 /* By the time we get here, we should be seeing only real
8732 pointer-to-member types, not the internal POINTER_TYPE to
8733 METHOD_TYPE representation. */
8739 /* Check that the TARGET_TYPE is reasonable. */
8744 /* This is OK, too. */
8747 /* This is OK, too. This comes from a conversion to reference
8748 type. */
8750 else
8751 {
8757 }
8759 /* Non-member functions and static member functions match targets of type
8760 "pointer-to-function" or "reference-to-function." Nonstatic member
8761 functions match targets of type "pointer-to-member-function;" the
8762 function type of the pointer to member is used to select the member
8763 function from the set of overloaded member functions.
8765 So figure out the FUNCTION_TYPE that we want to match against. */
8768 /* If we can find a non-template function that matches, we can just
8769 use it. There's no point in generating template instantiations
8770 if we're just going to throw them out anyhow. But, of course, we
8771 can only do this when we don't *need* a template function. */
8774 {
8778 /* We're not looking for templates just yet. */
8782 /* We're looking for a non-static member, and this isn't
8783 one, or vice versa. */
8786 /* Constraints must be satisfied. This is done before
8787 return type deduction since that instantiates the
8788 function. */
8793 {
8794 /* Force instantiation to do return type deduction. */
8797 }
8799 /* In C++17 we need the noexcept-qualifier to compare types. */
8804 /* See if there's a match. */
8809 }
8811 /* Now, if we've already got a match (or matches), there's no need
8812 to proceed to the template functions. But, if we don't have a
8813 match we need to look at them, too. */
8815 {
8816 tree target_arg_types;
8817 tree target_ret_type;
8820 tree arg;
8834 {
8836 tree instantiation;
8837 tree targs;
8840 /* We're only looking for templates. */
8845 /* We're not looking for a non-static member, and this is
8846 one, or vice versa. */
8851 /* If the template has a deduced return type, don't expose it to
8852 template argument deduction. */
8856 /* Try to do argument deduction. */
8863 /* Instantiation failed. */
8866 /* Constraints must be satisfied. This is done before
8867 return type deduction since that instantiates the
8868 function. */
8872 /* And now force instantiation to do return type deduction. */
8874 {
8880 }
8882 /* In C++17 we need the noexcept-qualifier to compare types. */
8886 /* See if there's a match. */
8891 }
8893 /* Now, remove all but the most specialized of the matches. */
8895 {
8899 {
8902 }
8903 }
8904 }
8907 {
8910 }
8912 /* Now we should have exactly one function in MATCHES. */
8914 {
8915 /* There were *no* matches. */
8917 {
8918 auto_diagnostic_group d;
8923 }
8925 }
8927 {
8928 /* There were too many matches. First check if they're all
8929 the same function. */
8934 /* For multi-versioned functions, more than one match is just fine and
8935 decls_match will return false as they are different. */
8943 {
8945 {
8946 auto_diagnostic_group d;
8950 /* Since print_candidates expects the functions in the
8951 TREE_VALUE slot, we flip them here. */
8956 }
8959 }
8960 }
8962 /* Good, exactly one match. Now, convert it to the correct type. */
8967 {
8968 /* Previously we allowed this behavior for iobj member functions when the
8969 -fms-extensions flag is passed as MSVC allows this as a language
8970 extension. MSVC also allows this for xobj member functions, but the
8971 documentation for -fms-extensions states it's purpose is to support
8972 the use of microsoft headers. Until otherwise demonstrated, we should
8973 assume xobj member functions are not used in this manner in microsoft
8974 headers and forbid the incorrect syntax instead of supporting it for
8975 non-legacy uses. This should hopefully encourage conformance going
8976 forward.
8977 This comment is referred to in typeck.cc:cp_build_addr_expr_1. */
8983 {
8984 auto_diagnostic_group d;
8985 /* Should match the error in typeck.cc:cp_build_addr_expr_1.
8986 We seem to lack the details here to match that diagnostic exactly,
8987 perhaps this could be fixed in the future? See PR113075 bug 2. */
8989 "ISO C++ forbids taking the address of an unqualified"
8990 " or parenthesized non-static member function to form"
8992 /* This is incorrect, see PR113075 bug 3. */
8994 "a pointer to explicit object member function can only be "
8996 }
8997 else
8998 {
9001 /* Is there a reason this error message doesn't match the one in
9002 typeck.cc:cp_build_addr_expr_1? */
9003 auto_diagnostic_group d;
9006 {
9010 }
9011 }
9012 }
9014 /* If a pointer to a function that is multi-versioned is requested, the
9015 pointer to the dispatcher function is returned instead. This works
9016 well because indirectly calling the function will dispatch the right
9017 function version at run-time. */
9019 {
9023 /* Mark all the versions corresponding to the dispatcher as used. */
9026 }
9028 /* If we're doing overload resolution purely for the purpose of
9029 determining conversion sequences, we should not consider the
9030 function used. If this conversion sequence is selected, the
9031 function will be marked as used at this point. */
9033 {
9034 /* Make =delete work with SFINAE. */
9039 }
9041 /* We could not check access to member functions when this
9042 expression was originally created since we did not know at that
9043 time to which function the expression referred. */
9045 {
9048 }
9052 else
9053 {
9054 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
9055 will mark the function as addressed, but here we must do it
9056 explicitly. */
9060 }
9061 }
9063 /* This function will instantiate the type of the expression given in
9064 RHS to match the type of LHSTYPE. If errors exist, then return
9065 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
9066 we complain on errors. If we are not complaining, never modify rhs,
9067 as overload resolution wants to try many possible instantiations, in
9068 the hope that at least one will work.
9070 For non-recursive calls, LHSTYPE should be a function, pointer to
9071 function, or a pointer to member function. */
9073 tree
9075 {
9084 {
9088 }
9091 {
9100 /* Microsoft allows `A::f' to be resolved to a
9101 pointer-to-member. */
9102 ;
9103 else
9104 {
9109 }
9110 }
9112 /* If we instantiate a template, and it is a A ?: C expression
9113 with omitted B, look through the SAVE_EXPR. */
9118 {
9121 }
9123 /* There are only a few kinds of expressions that may have a type
9124 dependent on overload resolution. */
9130 /* This should really only be used when attempting to distinguish
9131 what sort of a pointer to function we have. For now, any
9132 arithmetic operation which is not supported on pointers
9133 is rejected as an error. */
9136 {
9138 {
9144 /* Do not lose object's side effects. */
9148 }
9155 /* This can happen if we are forming a pointer-to-member for a
9156 member template. */
9159 /* Fall through. */
9162 {
9166 return
9170 }
9174 return
9178 access_path);
9181 {
9186 }
9193 }
9195 }
9196 \f
9197 /* Return the name of the virtual function pointer field
9198 (as an IDENTIFIER_NODE) for the given TYPE. Note that
9199 this may have to look back through base types to find the
9200 ultimate field name. (For single inheritance, these could
9201 all be the same name. Who knows for multiple inheritance). */
9203 static tree
9205 {
9211 {
9217 }
9225 }
9227 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
9228 according to [class]:
9229 The class-name is also inserted
9230 into the scope of the class itself. For purposes of access checking,
9231 the inserted class name is treated as if it were a public member name. */
9233 void
9235 {
9253 }
9255 /* Returns 1 if TYPE contains only padding bytes. */
9257 int
9259 {
9267 }
9269 /* Returns true if TYPE contains no actual data, just various
9270 possible combinations of empty classes. If IGNORE_VPTR is true,
9271 a vptr doesn't prevent the class from being considered empty. Typically
9272 we want to ignore the vptr on assignment, and not on initialization. */
9274 bool
9276 {
9278 {
9279 tree field;
9280 tree binfo;
9281 tree base_binfo;
9284 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
9285 out, but we'd like to be able to check this before then. */
9299 /* An unnamed bit-field is not a data member. */
9304 }
9309 }
9311 /* Note that NAME was looked up while the current class was being
9312 defined and that the result of that lookup was DECL. */
9314 void
9316 {
9317 /* If we're not defining a class, there's nothing to do. */
9328 /* Record the binding in the names_used tables for classes inside blev. */
9330 {
9332 ? current_class_type
9336 {
9338 /* We found the declaration. */
9341 /* This class is inside the declaration scope. */
9343 }
9355 }
9356 }
9358 /* Note that NAME was declared (as DECL) in the current class. Check
9359 to see that the declaration is valid under [class.member.lookup]:
9361 If [the result of a search in T for N at point P] differs from the result of
9362 a search in T for N from immediately after the class-specifier of T, the
9363 program is ill-formed, no diagnostic required. */
9365 void
9367 {
9368 splay_tree names_used;
9369 splay_tree_node n;
9371 /* Look to see if we ever used this name. */
9372 names_used
9376 /* The C language allows members to be declared with a type of the same
9377 name, and the C++ standard says this diagnostic is not required. So
9378 allow it in extern "C" blocks unless pedantic is specified.
9379 Allow it in all cases if -ms-extensions is specified. */
9385 {
9389 /* [basic.scope.class]
9391 A name N used in a class S shall refer to the same declaration
9392 in its context and when re-evaluated in the completed scope of
9393 S. */
9401 else
9402 /* Make it an error. */
9405 auto_diagnostic_group d;
9409 {
9412 }
9413 }
9414 }
9416 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
9417 Secondary vtables are merged with primary vtables; this function
9418 will return the VAR_DECL for the primary vtable. */
9420 tree
9422 {
9423 tree decl;
9427 {
9430 }
9434 }
9437 /* Returns the binfo for the primary base of BINFO. If the resulting
9438 BINFO is a virtual base, and it is inherited elsewhere in the
9439 hierarchy, then the returned binfo might not be the primary base of
9440 BINFO in the complete object. Check BINFO_PRIMARY_P or
9441 BINFO_LOST_PRIMARY_P to be sure. */
9443 static tree
9445 {
9446 tree primary_base;
9453 }
9455 /* As above, but iterate until we reach the binfo that actually provides the
9456 vptr for BINFO. */
9458 static tree
9460 {
9464 {
9469 }
9471 }
9473 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
9474 type. Note that the virtual inheritance might be above or below BINFO in
9475 the hierarchy. */
9477 bool
9479 {
9483 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
9484 a morally virtual base. */
9487 }
9489 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
9491 static int
9493 {
9497 }
9499 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
9500 INDENT should be zero when called from the top level; it is
9501 incremented recursively. IGO indicates the next expected BINFO in
9502 inheritance graph ordering. */
9504 static tree
9506 dump_flags_t flags,
9507 tree binfo,
9508 tree igo,
9510 {
9512 tree base_binfo;
9519 {
9522 }
9536 {
9540 TFF_PLAIN_IDENTIFIER),
9542 }
9544 {
9547 }
9552 {
9556 {
9560 TFF_PLAIN_IDENTIFIER));
9561 }
9563 {
9567 TFF_PLAIN_IDENTIFIER));
9568 }
9570 {
9574 TFF_PLAIN_IDENTIFIER));
9575 }
9577 {
9581 TFF_PLAIN_IDENTIFIER));
9582 }
9586 }
9592 }
9594 /* Dump the BINFO hierarchy for T. */
9596 static void
9598 {
9610 }
9612 /* Debug interface to hierarchy dumping. */
9614 void
9616 {
9618 }
9620 static void
9622 {
9623 dump_flags_t flags;
9625 {
9628 }
9629 }
9631 static void
9633 {
9634 tree value;
9636 HOST_WIDE_INT elt;
9644 TFF_PLAIN_IDENTIFIER));
9651 }
9653 static void
9655 {
9656 dump_flags_t flags;
9663 {
9670 {
9675 }
9679 }
9682 }
9684 static void
9686 {
9687 dump_flags_t flags;
9694 {
9699 }
9702 }
9704 /* Dump a function or thunk and its thunkees. */
9706 static void
9708 {
9711 tree thunks;
9719 {
9729 else
9735 }
9739 }
9741 /* Dump the thunks for FN. */
9743 void
9745 {
9747 }
9749 /* Virtual function table initialization. */
9751 /* Create all the necessary vtables for T and its base classes. */
9753 static void
9755 {
9756 tree vbase;
9760 /* We lay out the primary and secondary vtables in one contiguous
9761 vtable. The primary vtable is first, followed by the non-virtual
9762 secondary vtables in inheritance graph order. */
9766 /* Then come the virtual bases, also in inheritance graph order. */
9768 {
9772 }
9776 }
9778 /* Initialize the vtable for BINFO with the INITS. */
9780 static void
9782 {
9783 tree decl;
9789 }
9791 /* Build the VTT (virtual table table) for T.
9792 A class requires a VTT if it has virtual bases.
9794 This holds
9795 1 - primary virtual pointer for complete object T
9796 2 - secondary VTTs for each direct non-virtual base of T which requires a
9797 VTT
9798 3 - secondary virtual pointers for each direct or indirect base of T which
9799 has virtual bases or is reachable via a virtual path from T.
9800 4 - secondary VTTs for each direct or indirect virtual base of T.
9802 Secondary VTTs look like complete object VTTs without part 4. */
9804 static void
9806 {
9807 tree type;
9808 tree vtt;
9809 tree index;
9812 /* Build up the initializers for the VTT. */
9817 /* If we didn't need a VTT, we're done. */
9821 /* Figure out the type of the VTT. */
9825 /* Now, build the VTT object itself. */
9828 /* Add the VTT to the vtables list. */
9833 }
9835 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
9836 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
9837 and CHAIN the vtable pointer for this binfo after construction is
9838 complete. VALUE can also be another BINFO, in which case we recurse. */
9840 static tree
9842 {
9843 tree vt;
9846 {
9852 else
9854 }
9857 }
9859 /* Data for secondary VTT initialization. */
9860 struct secondary_vptr_vtt_init_data
9861 {
9862 /* Is this the primary VTT? */
9865 /* Current index into the VTT. */
9866 tree index;
9868 /* Vector of initializers built up. */
9871 /* The type being constructed by this secondary VTT. */
9872 tree type_being_constructed;
9873 };
9875 /* Recursively build the VTT-initializer for BINFO (which is in the
9876 hierarchy dominated by T). INITS points to the end of the initializer
9877 list to date. INDEX is the VTT index where the next element will be
9878 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
9879 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
9880 for virtual bases of T. When it is not so, we build the constructor
9881 vtables for the BINFO-in-T variant. */
9883 static void
9886 {
9888 tree b;
9889 tree init;
9890 secondary_vptr_vtt_init_data data;
9893 /* We only need VTTs for subobjects with virtual bases. */
9897 /* We need to use a construction vtable if this is not the primary
9898 VTT. */
9900 {
9903 /* Record the offset in the VTT where this sub-VTT can be found. */
9905 }
9907 /* Add the address of the primary vtable for the complete object. */
9911 {
9914 }
9917 /* Recursively add the secondary VTTs for non-virtual bases. */
9922 /* Add secondary virtual pointers for all subobjects of BINFO with
9923 either virtual bases or reachable along a virtual path, except
9924 subobjects that are non-virtual primary bases. */
9934 /* data.inits might have grown as we added secondary virtual pointers.
9935 Make sure our caller knows about the new vector. */
9939 /* Add the secondary VTTs for virtual bases in inheritance graph
9940 order. */
9942 {
9947 }
9948 else
9949 /* Remove the ctor vtables we created. */
9951 }
9953 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
9954 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
9956 static tree
9958 {
9961 /* We don't care about bases that don't have vtables. */
9965 /* We're only interested in proper subobjects of the type being
9966 constructed. */
9970 /* We're only interested in bases with virtual bases or reachable
9971 via a virtual path from the type being constructed. */
9976 /* We're not interested in non-virtual primary bases. */
9980 /* Record the index where this secondary vptr can be found. */
9982 {
9987 {
9988 /* It's a primary virtual base, and this is not a
9989 construction vtable. Find the base this is primary of in
9990 the inheritance graph, and use that base's vtable
9991 now. */
9994 }
9995 }
9997 /* Add the initializer for the secondary vptr itself. */
10000 /* Advance the vtt index. */
10005 }
10007 /* Called from build_vtt_inits via dfs_walk. After building
10008 constructor vtables and generating the sub-vtt from them, we need
10009 to restore the BINFO_VTABLES that were scribbled on. DATA is the
10010 binfo of the base whose sub vtt was generated. */
10012 static tree
10014 {
10018 /* If this class has no vtable, none of its bases do. */
10022 /* This might be a primary base, so have no vtable in this
10023 hierarchy. */
10026 /* If we scribbled the construction vtable vptr into BINFO, clear it
10027 out now. */
10033 }
10035 /* Build the construction vtable group for BINFO which is in the
10036 hierarchy dominated by T. */
10038 static void
10040 {
10041 tree type;
10042 tree vtbl;
10043 tree id;
10044 tree vbase;
10047 /* See if we've already created this construction vtable group. */
10053 /* Build a version of VTBL (with the wrong type) for use in
10054 constructing the addresses of secondary vtables in the
10055 construction vtable group. */
10058 /* Don't export construction vtables from shared libraries. Even on
10059 targets that don't support hidden visibility, this tells
10060 can_refer_decl_in_current_unit_p not to assume that it's safe to
10061 access from a different compilation unit (bz 54314). */
10069 /* Add the vtables for each of our virtual bases using the vbase in T
10070 binfo. */
10072 vbase;
10074 {
10075 tree b;
10082 }
10084 /* Figure out the type of the construction vtable. */
10091 /* Initialize the construction vtable. */
10095 }
10097 /* Add the vtbl initializers for BINFO (and its bases other than
10098 non-virtual primaries) to the list of INITS. BINFO is in the
10099 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
10100 the constructor the vtbl inits should be accumulated for. (If this
10101 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
10102 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
10103 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
10104 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
10105 but are not necessarily the same in terms of layout. */
10107 static void
10109 tree orig_binfo,
10110 tree rtti_binfo,
10111 tree vtbl,
10112 tree t,
10114 {
10116 tree base_binfo;
10121 /* If it doesn't have a vptr, we don't do anything. */
10125 /* If we're building a construction vtable, we're not interested in
10126 subobjects that don't require construction vtables. */
10132 /* Build the initializers for the BINFO-in-T vtable. */
10135 /* Walk the BINFO and its bases. We walk in preorder so that as we
10136 initialize each vtable we can figure out at what offset the
10137 secondary vtable lies from the primary vtable. We can't use
10138 dfs_walk here because we need to iterate through bases of BINFO
10139 and RTTI_BINFO simultaneously. */
10141 {
10142 /* Skip virtual bases. */
10148 inits);
10149 }
10150 }
10152 /* Called from accumulate_vtbl_inits. Adds the initializers for the
10153 BINFO vtable to L. */
10155 static void
10157 tree orig_binfo,
10158 tree rtti_binfo,
10159 tree orig_vtbl,
10160 tree t,
10162 {
10169 {
10170 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
10171 primary virtual base. If it is not the same primary in
10172 the hierarchy of T, we'll need to generate a ctor vtable
10173 for it, to place at its location in T. If it is the same
10174 primary, we still need a VTT entry for the vtable, but it
10175 should point to the ctor vtable for the base it is a
10176 primary for within the sub-hierarchy of RTTI_BINFO.
10178 There are three possible cases:
10180 1) We are in the same place.
10181 2) We are a primary base within a lost primary virtual base of
10182 RTTI_BINFO.
10183 3) We are primary to something not a base of RTTI_BINFO. */
10185 tree b;
10188 /* First, look through the bases we are primary to for RTTI_BINFO
10189 or a virtual base. */
10192 {
10197 }
10198 /* If we run out of primary links, keep looking down our
10199 inheritance chain; we might be an indirect primary. */
10203 found:
10205 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
10206 base B and it is a base of RTTI_BINFO, this is case 2. In
10207 either case, we share our vtable with LAST, i.e. the
10208 derived-most base within B of which we are a primary. */
10211 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
10212 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
10213 binfo_ctor_vtable after everything's been set up. */
10216 /* Otherwise, this is case 3 and we get our own. */
10217 }
10224 {
10225 tree index;
10228 /* Add the initializer for this vtable. */
10232 /* Figure out the position to which the VPTR should point. */
10238 }
10241 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
10242 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
10243 straighten this out. */
10246 /* Throw away any unneeded intializers. */
10248 else
10249 /* For an ordinary vtable, set BINFO_VTABLE. */
10251 }
10256 /* Construct the initializer for BINFO's virtual function table. BINFO
10257 is part of the hierarchy dominated by T. If we're building a
10258 construction vtable, the ORIG_BINFO is the binfo we should use to
10259 find the actual function pointers to put in the vtable - but they
10260 can be overridden on the path to most-derived in the graph that
10261 ORIG_BINFO belongs. Otherwise,
10262 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
10263 BINFO that should be indicated by the RTTI information in the
10264 vtable; it will be a base class of T, rather than T itself, if we
10265 are building a construction vtable.
10267 The value returned is a TREE_LIST suitable for wrapping in a
10268 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
10269 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
10270 number of non-function entries in the vtable.
10272 It might seem that this function should never be called with a
10273 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
10274 base is always subsumed by a derived class vtable. However, when
10275 we are building construction vtables, we do build vtables for
10276 primary bases; we need these while the primary base is being
10277 constructed. */
10279 static void
10281 tree orig_binfo,
10282 tree t,
10283 tree rtti_binfo,
10286 {
10287 tree v;
10288 vtbl_init_data vid;
10290 tree vbinfo;
10294 /* Initialize VID. */
10302 /* The first vbase or vcall offset is at index -3 in the vtable. */
10305 /* Add entries to the vtable for RTTI. */
10308 /* Create an array for keeping track of the functions we've
10309 processed. When we see multiple functions with the same
10310 signature, we share the vcall offsets. */
10312 /* Add the vcall and vbase offset entries. */
10315 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
10316 build_vbase_offset_vtbl_entries. */
10321 /* If the target requires padding between data entries, add that now. */
10323 {
10329 /* Move data entries into their new positions and add padding
10330 after the new positions. Iterate backwards so we don't
10331 overwrite entries that we would need to process later. */
10334 ix--)
10335 {
10343 {
10347 null_pointer_node);
10348 }
10349 }
10350 }
10355 /* The initializers for virtual functions were built up in reverse
10356 order. Straighten them out and add them to the running list in one
10357 step. */
10366 /* Go through all the ordinary virtual functions, building up
10367 initializers. */
10369 {
10370 tree delta;
10371 tree vcall_index;
10378 {
10382 {
10385 }
10387 }
10389 /* If the only definition of this function signature along our
10390 primary base chain is from a lost primary, this vtable slot will
10391 never be used, so just zero it out. This is important to avoid
10392 requiring extra thunks which cannot be generated with the function.
10394 We first check this in update_vtable_entry_for_fn, so we handle
10395 restored primary bases properly; we also need to do it here so we
10396 zero out unused slots in ctor vtables, rather than filling them
10397 with erroneous values (though harmless, apart from relocation
10398 costs). */
10403 {
10404 /* Pull the offset for `this', and the function to call, out of
10405 the list. */
10412 /* You can't call an abstract virtual function; it's abstract.
10413 So, we replace these functions with __pure_virtual. */
10415 {
10418 {
10420 abort_fndecl_addr
10424 }
10425 }
10426 /* Likewise for deleted virtuals. */
10428 {
10430 {
10434 dvirt_fn = push_library_fn
10438 }
10443 }
10444 else
10445 {
10447 {
10452 }
10453 /* Take the address of the function, considering it to be of an
10454 appropriate generic type. */
10458 /* Don't refer to a virtual destructor from a constructor
10459 vtable or a vtable for an abstract class, since destroying
10460 an object under construction is undefined behavior and we
10461 don't want it to be considered a candidate for speculative
10462 devirtualization. But do create the thunk for ABI
10463 compliance. */
10468 }
10469 }
10471 /* And add it to the chain of initializers. */
10473 {
10478 else
10480 {
10486 }
10487 }
10488 else
10490 }
10491 }
10493 /* Adds to vid->inits the initializers for the vbase and vcall
10494 offsets in BINFO, which is in the hierarchy dominated by T. */
10496 static void
10498 {
10499 tree b;
10501 /* If this is a derived class, we must first create entries
10502 corresponding to the primary base class. */
10507 /* Add the vbase entries for this base. */
10509 /* Add the vcall entries for this base. */
10511 }
10513 /* Returns the initializers for the vbase offset entries in the vtable
10514 for BINFO (which is part of the class hierarchy dominated by T), in
10515 reverse order. VBASE_OFFSET_INDEX gives the vtable index
10516 where the next vbase offset will go. */
10518 static void
10520 {
10521 tree vbase;
10522 tree t;
10523 tree non_primary_binfo;
10525 /* If there are no virtual baseclasses, then there is nothing to
10526 do. */
10532 /* We might be a primary base class. Go up the inheritance hierarchy
10533 until we find the most derived class of which we are a primary base:
10534 it is the offset of that which we need to use. */
10537 {
10538 tree b;
10540 /* If we have reached a virtual base, then it must be a primary
10541 base (possibly multi-level) of vid->binfo, or we wouldn't
10542 have called build_vcall_and_vbase_vtbl_entries for it. But it
10543 might be a lost primary, so just skip down to vid->binfo. */
10545 {
10548 }
10554 }
10556 /* Go through the virtual bases, adding the offsets. */
10558 vbase;
10560 {
10561 tree b;
10562 tree delta;
10567 /* Find the instance of this virtual base in the complete
10568 object. */
10571 /* If we've already got an offset for this virtual base, we
10572 don't need another one. */
10577 /* Figure out where we can find this vbase offset. */
10586 /* The vbase offset had better be the same. */
10589 /* The next vbase will come at a more negative offset. */
10593 /* The initializer is the delta from BINFO to this virtual base.
10594 The vbase offsets go in reverse inheritance-graph order, and
10595 we are walking in inheritance graph order so these end up in
10596 the right order. */
10603 }
10604 }
10606 /* Adds the initializers for the vcall offset entries in the vtable
10607 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
10608 to VID->INITS. */
10610 static void
10612 {
10613 /* We only need these entries if this base is a virtual base. We
10614 compute the indices -- but do not add to the vtable -- when
10615 building the main vtable for a class. */
10618 /* If BINFO is RTTI_BINFO, then (since BINFO does not
10619 correspond to VID->DERIVED), we are building a primary
10620 construction virtual table. Since this is a primary
10621 virtual table, we do not need the vcall offsets for
10622 BINFO. */
10624 {
10625 /* We need a vcall offset for each of the virtual functions in this
10626 vtable. For example:
10628 class A { virtual void f (); };
10629 class B1 : virtual public A { virtual void f (); };
10630 class B2 : virtual public A { virtual void f (); };
10631 class C: public B1, public B2 { virtual void f (); };
10633 A C object has a primary base of B1, which has a primary base of A. A
10634 C also has a secondary base of B2, which no longer has a primary base
10635 of A. So the B2-in-C construction vtable needs a secondary vtable for
10636 A, which will adjust the A* to a B2* to call f. We have no way of
10637 knowing what (or even whether) this offset will be when we define B2,
10638 so we store this "vcall offset" in the A sub-vtable and look it up in
10639 a "virtual thunk" for B2::f.
10641 We need entries for all the functions in our primary vtable and
10642 in our non-virtual bases' secondary vtables. */
10644 /* If we are just computing the vcall indices -- but do not need
10645 the actual entries -- not that. */
10648 /* Now, walk through the non-virtual bases, adding vcall offsets. */
10650 }
10651 }
10653 /* Build vcall offsets, starting with those for BINFO. */
10655 static void
10657 {
10659 tree primary_binfo;
10660 tree base_binfo;
10662 /* Don't walk into virtual bases -- except, of course, for the
10663 virtual base for which we are building vcall offsets. Any
10664 primary virtual base will have already had its offsets generated
10665 through the recursion in build_vcall_and_vbase_vtbl_entries. */
10669 /* If BINFO has a primary base, process it first. */
10674 /* Add BINFO itself to the list. */
10677 /* Scan the non-primary bases of BINFO. */
10681 }
10683 /* Called from build_vcall_offset_vtbl_entries_r. */
10685 static void
10687 {
10688 /* Make entries for the rest of the virtuals. */
10689 tree orig_fn;
10691 /* The ABI requires that the methods be processed in declaration
10692 order. */
10694 orig_fn;
10698 }
10700 /* Add a vcall offset entry for ORIG_FN to the vtable. */
10702 static void
10704 {
10706 tree vcall_offset;
10707 tree derived_entry;
10709 /* If there is already an entry for a function with the same
10710 signature as FN, then we do not need a second vcall offset.
10711 Check the list of functions already present in the derived
10712 class vtable. */
10714 {
10716 /* We only use one vcall offset for virtual destructors,
10717 even though there are two virtual table entries. */
10721 }
10723 /* If we are building these vcall offsets as part of building
10724 the vtable for the most derived class, remember the vcall
10725 offset. */
10727 {
10730 }
10732 /* The next vcall offset will be found at a more negative
10733 offset. */
10737 /* Keep track of this function. */
10741 {
10742 tree base;
10743 tree fn;
10745 /* Find the overriding function. */
10749 else
10750 {
10753 /* The vbase we're working on is a primary base of
10754 vid->binfo. But it might be a lost primary, so its
10755 BINFO_OFFSET might be wrong, so we just use the
10756 BINFO_OFFSET from vid->binfo. */
10762 vcall_offset);
10763 }
10764 /* Add the initializer to the vtable. */
10766 }
10767 }
10769 /* Return vtbl initializers for the RTTI entries corresponding to the
10770 BINFO's vtable. The RTTI entries should indicate the object given
10771 by VID->rtti_binfo. */
10773 static void
10775 {
10776 tree b;
10777 tree t;
10778 tree offset;
10779 tree decl;
10780 tree init;
10784 /* To find the complete object, we will first convert to our most
10785 primary base, and then add the offset in the vtbl to that value. */
10790 /* The second entry is the address of the typeinfo object. */
10793 else
10796 /* Convert the declaration to a type that can be stored in the
10797 vtable. */
10801 /* Add the offset-to-top entry. It comes earlier in the vtable than
10802 the typeinfo entry. Convert the offset to look like a
10803 function pointer, so that we can put it in the vtable. */
10806 }
10808 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
10809 accessibility. */
10811 bool
10813 {
10816 }
10818 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
10820 bool
10822 {
10826 }
10828 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
10829 class between them, if any. */
10831 tree
10833 {
10845 {
10848 }
10852 }