| blob | 469e98ed8b7559cf7cfc0fc081565e983d1c625d |
1 /* Functions related to building -*- C++ -*- classes and their related objects.
2 Copyright (C) 1987-2023 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);
209 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
211 void
213 {
218 else
220 }
222 /* Return a COND_EXPR that executes TRUE_STMT if this execution of the
223 'structor is in charge of 'structing virtual bases, or FALSE_STMT
224 otherwise. */
226 tree
228 {
238 }
240 /* Convert to or from a base subobject. EXPR is an expression of type
241 `A' or `A*', an expression of type `B' or `B*' is returned. To
242 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
243 the B base instance within A. To convert base A to derived B, CODE
244 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
245 In this latter case, A must not be a morally virtual base of B.
246 NONNULL is true if EXPR is known to be non-NULL (this is only
247 needed when EXPR is of pointer type). CV qualifiers are preserved
248 from EXPR. */
250 tree
252 tree expr,
253 tree binfo,
255 tsubst_flags_t complain)
256 {
259 tree probe;
260 tree offset;
261 tree target_type;
263 tree ptr_target_type;
274 {
280 }
291 {
292 /* This can happen when adjust_result_of_qualified_name_lookup can't
293 find a unique base binfo in a call to a member function. We
294 couldn't give the diagnostic then since we might have been calling
295 a static member function, so we do it now. In other cases, eg.
296 during error recovery (c++/71979), we may not have a base at all. */
298 {
302 }
304 }
311 /* Nothing to do. */
315 {
317 {
319 {
322 "pointer to derived class %qT because the base is "
324 else
328 }
329 else
330 {
336 else
340 }
341 }
343 }
346 || processing_template_decl
349 /* For a non-pointer simple base reference, express it as a COMPONENT_REF
350 without taking its address (and so causing lambda capture, 91933). */
355 {
357 /* This must happen before the call to save_expr. */
359 }
360 else
366 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
367 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
368 expression returned matches the input. */
369 target_type = cp_build_qualified_type
373 /* Do we need to look in the vtable for the real offset? */
376 /* Don't bother with the calculations inside sizeof; they'll ICE if the
377 source type is incomplete and the pointer value doesn't matter. In a
378 template (even in instantiate_non_dependent_expr), we don't have vtables
379 set up properly yet, and the value doesn't matter there either; we're
380 just interested in the result of overload resolution. */
382 {
385 }
388 {
394 }
396 /* If we're in an NSDMI, we don't have the full constructor context yet
397 that we need for converting to a virtual base, so just build a stub
398 CONVERT_EXPR and expand it later in bot_replace. */
401 {
405 }
407 /* Do we need to check for a null pointer? */
409 {
410 /* If we know the conversion will not actually change the value
411 of EXPR, then we can avoid testing the expression for NULL.
412 We have to avoid generating a COMPONENT_REF for a base class
413 field, because other parts of the compiler know that such
414 expressions are always non-NULL. */
418 }
420 /* Protect against multiple evaluation if necessary. */
424 /* Store EXPR and build the real null test just before returning. */
428 /* If this is a simple base reference, express it as a COMPONENT_REF. */
430 /* We don't build base fields for empty bases, and they aren't very
431 interesting to the optimizers anyway. */
433 {
442 }
445 {
446 /* Going via virtual base V_BINFO. We need the static offset
447 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
448 V_BINFO. That offset is an entry in D_BINFO's vtable. */
449 tree v_offset;
452 {
453 /* In a base member initializer, we cannot rely on the
454 vtable being set up. We have to indirect via the
455 vtt_parm. */
456 tree t;
462 }
463 else
464 {
468 {
473 }
476 }
484 v_offset);
496 /* Negative fixed_type_p means this is a constructor or destructor;
497 virtual base layout is fixed in in-charge [cd]tors, but not in
498 base [cd]tors. */
499 offset = build_if_in_charge
501 v_offset);
502 else
504 }
510 {
515 }
516 else
521 indout:
523 {
527 }
529 out:
531 /* Wrap EXPR in a null test. */
535 }
537 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
538 Perform a derived-to-base conversion by recursively building up a
539 sequence of COMPONENT_REFs to the appropriate base fields. */
541 static tree
543 {
546 tree field;
549 {
550 tree temp;
554 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
555 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
556 an lvalue in the front end; only _DECLs and _REFs are lvalues
557 in the back end. */
563 }
565 /* Recurse. */
570 /* Is this the base field created by build_base_field? */
574 /* If we're looking for a field in the most-derived class,
575 also check the field offset; we can have two base fields
576 of the same type if one is an indirect virtual base and one
577 is a direct non-virtual base. */
581 {
582 /* We don't use build_class_member_access_expr here, as that
583 has unnecessary checks, and more importantly results in
584 recursive calls to dfs_walk_once. */
590 /* Mark the expression const or volatile, as appropriate.
591 Even though we've dealt with the type above, we still have
592 to mark the expression itself. */
599 }
601 /* Didn't find the base field?!? */
603 }
605 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
606 type is a class type or a pointer to a class type. In the former
607 case, TYPE is also a class type; in the latter it is another
608 pointer type. If CHECK_ACCESS is true, an error message is emitted
609 if TYPE is inaccessible. If OBJECT has pointer type, the value is
610 assumed to be non-NULL. */
612 tree
614 tsubst_flags_t complain)
615 {
616 tree binfo;
617 tree object_type;
620 {
623 }
624 else
633 }
635 /* EXPR is an expression with unqualified class type. BASE is a base
636 binfo of that class type. Returns EXPR, converted to the BASE
637 type. This function assumes that EXPR is the most derived class;
638 therefore virtual bases can be found at their static offsets. */
640 tree
642 {
643 tree expr_type;
647 {
648 /* If this is a non-empty base, use a COMPONENT_REF. */
652 /* We use fold_build2 and fold_convert below to simplify the trees
653 provided to the optimizers. It is not safe to call these functions
654 when processing a template because they do not handle C++-specific
655 trees. */
663 }
666 }
668 /* True IFF EXPR is a reference to an empty base class "subobject", as built in
669 convert_to_base_statically. We look for the result of the fold_convert
670 call, a NOP_EXPR from one pointer type to another, where the target is an
671 empty base of the original type. */
673 bool
675 {
694 }
695 \f
696 tree
698 {
702 /* Can happen in case of duplicate base types (c++/59082). */
706 /* First, convert to the requested type. */
711 /* Second, the requested type may not be the owner of its own vptr.
712 If not, convert to the base class that owns it. We cannot use
713 convert_to_base here, because VCONTEXT may appear more than once
714 in the inheritance hierarchy of TYPE, and thus direct conversion
715 between the types may be ambiguous. Following the path back up
716 one step at a time via primary bases avoids the problem. */
720 {
723 }
726 }
728 /* Given an object INSTANCE, return an expression which yields the
729 vtable element corresponding to INDEX. There are many special
730 cases for INSTANCE which we take care of here, mainly to avoid
731 creating extra tree nodes when we don't have to. */
733 tree
735 {
736 tree aref;
739 /* Try to figure out what a reference refers to, and
740 access its virtual function table directly. */
748 {
753 }
762 }
764 /* Given a stable object pointer INSTANCE_PTR, return an expression which
765 yields a function pointer corresponding to vtable element INDEX. */
767 tree
769 {
770 tree aref;
774 /* When using function descriptors, the address of the
775 vtable entry is treated as a function pointer. */
780 /* Remember this as a method reference, for later devirtualization. */
785 }
787 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
788 for the given TYPE. */
790 static tree
792 {
794 }
796 /* DECL is an entity associated with TYPE, like a virtual table or an
797 implicitly generated constructor. Determine whether or not DECL
798 should have external or internal linkage at the object file
799 level. This routine does not deal with COMDAT linkage and other
800 similar complexities; it simply sets TREE_PUBLIC if it possible for
801 entities in other translation units to contain copies of DECL, in
802 the abstract. */
804 void
806 {
809 }
811 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
812 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
813 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
815 static tree
817 {
818 tree decl;
821 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
822 now to avoid confusion in mangle_decl. */
833 /* The vtable has not been defined -- yet. */
837 /* Mark the VAR_DECL node representing the vtable itself as a
838 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
839 is rather important that such things be ignored because any
840 effort to actually generate DWARF for them will run into
841 trouble when/if we encounter code like:
843 #pragma interface
844 struct S { virtual void member (); };
846 because the artificial declaration of the vtable itself (as
847 manufactured by the g++ front end) will say that the vtable is
848 a static member of `S' but only *after* the debug output for
849 the definition of `S' has already been output. This causes
850 grief because the DWARF entry for the definition of the vtable
851 will try to refer back to an earlier *declaration* of the
852 vtable as a static member of `S' and there won't be one. We
853 might be able to arrange to have the "vtable static member"
854 attached to the member list for `S' before the debug info for
855 `S' get written (which would solve the problem) but that would
856 require more intrusive changes to the g++ front end. */
860 }
862 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
863 or even complete. If this does not exist, create it. If COMPLETE is
864 nonzero, then complete the definition of it -- that will render it
865 impossible to actually build the vtable, but is useful to get at those
866 which are known to exist in the runtime. */
868 tree
870 {
871 tree decl;
880 {
883 }
886 }
888 /* Build the primary virtual function table for TYPE. If BINFO is
889 non-NULL, build the vtable starting with the initial approximation
890 that it is the same as the one which is the head of the association
891 list. Returns a nonzero value if a new vtable is actually
892 created. */
894 static int
896 {
897 tree decl;
898 tree virtuals;
903 {
905 /* We have already created a vtable for this base, so there's
906 no need to do it again. */
913 }
914 else
915 {
918 }
920 /* Initialize the association list for this type, based
921 on our first approximation. */
926 }
928 /* Give BINFO a new virtual function table which is initialized
929 with a skeleton-copy of its original initialization. The only
930 entry that changes is the `delta' entry, so we can really
931 share a lot of structure.
933 FOR_TYPE is the most derived type which caused this table to
934 be needed.
936 Returns nonzero if we haven't met BINFO before.
938 The order in which vtables are built (by calling this function) for
939 an object must remain the same, otherwise a binary incompatibility
940 can result. */
942 static int
944 {
946 /* We already created a vtable for this base. There's no need to
947 do it again. */
950 /* Remember that we've created a vtable for this BINFO, so that we
951 don't try to do so again. */
954 /* Make fresh virtual list, so we can smash it later. */
957 /* Secondary vtables are laid out as part of the same structure as
958 the primary vtable. */
961 }
963 /* Create a new vtable for BINFO which is the hierarchy dominated by
964 T. Return nonzero if we actually created a new vtable. */
966 static int
968 {
970 /* In this case, it is *type*'s vtable we are modifying. We start
971 with the approximation that its vtable is that of the
972 immediate base class. */
974 else
975 /* This is our very own copy of `basetype' to play with. Later,
976 we will fill in all the virtual functions that override the
977 virtual functions in these base classes which are not defined
978 by the current type. */
980 }
982 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
983 (which is in the hierarchy dominated by T) list FNDECL as its
984 BV_FN. DELTA is the required constant adjustment from the `this'
985 pointer where the vtable entry appears to the `this' required when
986 the function is actually called. */
988 static void
990 tree binfo,
991 tree fndecl,
992 tree delta,
994 {
995 tree v;
1001 {
1002 /* We need a new vtable for BINFO. */
1004 {
1005 /* If we really did make a new vtable, we also made a copy
1006 of the BINFO_VIRTUALS list. Now, we have to find the
1007 corresponding entry in that list. */
1012 }
1017 }
1018 }
1020 \f
1021 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
1022 METHOD is being injected via a using_decl. Returns true if the
1023 method could be added to the method vec. */
1025 bool
1027 {
1036 /* See below. */
1039 /* Check to see if we've already got this method. */
1041 {
1047 /* Two using-declarations can coexist, we'll complain about ambiguity in
1048 overload resolution. */
1050 /* Except handle inherited constructors specially. */
1052 {
1054 /* Don't add the same one twice. */
1057 }
1059 /* [over.load] Member function declarations with the
1060 same name and the same parameter types cannot be
1061 overloaded if any of them is a static member
1062 function declaration.
1064 [over.load] Member function declarations with the same name and
1065 the same parameter-type-list as well as member function template
1066 declarations with the same name, the same parameter-type-list, and
1067 the same template parameter lists cannot be overloaded if any of
1068 them, but not all, have a ref-qualifier.
1070 [namespace.udecl] When a using-declaration brings names
1071 from a base class into a derived class scope, member
1072 functions in the derived class override and/or hide member
1073 functions with the same name and parameter types in a base
1074 class (rather than conflicting). */
1078 /* Compare the quals on the 'this' parm. Don't compare
1079 the whole types, as used functions are treated as
1080 coming from the using class in overload resolution. */
1083 /* Either both or neither need to be ref-qualified for
1084 differing quals to allow overloading. */
1094 /* Templates and conversion ops must match return types. */
1099 /* For templates, the template parameters must be identical. */
1101 {
1108 }
1117 /* Bring back parameters omitted from an inherited ctor. The
1118 method and the function can have different omittedness. */
1122 parms2 = (FUNCTION_FIRST_USER_PARMTYPE
1129 {
1131 /* We can't check satisfaction in dependent context, wait until
1132 the class is instantiated. */
1140 /* Member function templates and non-special member functions
1141 coexist if they are not equivalently constrained. A member
1142 function is not hidden by an inherited constructor. */
1145 /* P0848: For special member functions, deleted, unsatisfied, or
1146 less constrained overloads are ineligible. We implement this
1147 by removing them from CLASSTYPE_MEMBER_VEC. Destructors don't
1148 use the notion of eligibility, and the selected destructor can
1149 be deleted, but removing unsatisfied or less constrained
1150 overloads has the same effect as overload resolution. */
1160 else
1163 /* Leave FN in the method vec, discard METHOD. */
1166 {
1167 /* Remove FN, add METHOD. */
1170 }
1171 else
1172 /* Let them coexist for now. */
1174 }
1176 /* If these are versions of the same function, process and
1177 move on. */
1183 {
1185 /* Defer to the other function. */
1191 {
1193 {
1194 /* Inheriting the same constructor along different
1195 paths, combine them. */
1196 SET_DECL_INHERITED_CTOR
1199 /* And discard the new one. */
1201 }
1202 else
1203 /* Inherited ctors can coexist until overload
1204 resolution. */
1206 }
1213 basef);
1215 }
1218 /* Defer to the local function. */
1221 || (flag_new_inheriting_ctors
1223 {
1224 /* Remove the inherited function. */
1227 }
1228 else
1229 {
1235 }
1236 }
1247 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1253 }
1255 /* Subroutines of finish_struct. */
1257 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1258 legit, otherwise return 0. */
1260 static int
1262 {
1263 tree elem;
1271 {
1273 {
1277 else
1280 }
1281 else
1282 {
1283 /* They're changing the access to the same thing they changed
1284 it to before. That's OK. */
1285 ;
1286 }
1287 }
1288 else
1289 {
1291 tf_warning_or_error);
1294 }
1296 }
1298 /* Return the access node for DECL's access in its enclosing class. */
1300 tree
1302 {
1306 }
1308 /* If DECL is a non-dependent using of non-ctor function members, push them
1309 and return true, otherwise return false. Called from
1310 finish_member_declaration. */
1312 bool
1314 {
1321 /* Add the functions to CLASSTYPE_MEMBER_VEC so that overload resolution
1322 works within the class body. */
1324 {
1326 /* Inheriting constructors are handled separately. */
1334 /* If add_method returns false because f was already declared, look
1335 for a duplicate using-declaration. */
1336 else
1341 {
1344 }
1345 }
1347 }
1349 /* Process the USING_DECL, which is a member of T. */
1351 static void
1353 {
1361 /* Handled in maybe_push_used_methods. */
1366 tf_warning_or_error);
1368 {
1373 else
1375 }
1378 ;
1380 {
1387 }
1389 {
1396 }
1401 /* Make type T see field decl FDECL with access ACCESS. */
1403 {
1404 /* C++20 using enum can import non-inherited enumerators into class
1405 scope. We implement that by making a copy of the CONST_DECL for which
1406 CONST_DECL_USING_P is true. */
1413 /* We emitted debug info for the USING_DECL above; make sure we don't
1414 also emit anything for this clone. */
1419 }
1420 else
1422 }
1423 \f
1424 /* Data structure for find_abi_tags_r, below. */
1426 struct abi_tag_data
1427 {
1431 };
1433 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1434 in the context of P. TAG can be either an identifier (the DECL_NAME of
1435 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1437 static void
1439 {
1441 {
1443 {
1444 /* We're collecting tags from template arguments or from
1445 the type of a variable or function return type. */
1448 /* Don't inherit this tag multiple times. */
1452 {
1453 /* Tags inherited from type template arguments are only used
1454 to avoid warnings. */
1457 }
1458 /* For functions and variables we want to warn, too. */
1459 }
1461 /* Otherwise we're diagnosing missing tags. */
1463 {
1464 auto_diagnostic_group d;
1469 }
1471 {
1472 auto_diagnostic_group d;
1476 }
1478 {
1479 auto_diagnostic_group d;
1484 }
1485 else
1486 {
1487 auto_diagnostic_group d;
1491 {
1495 }
1496 }
1497 }
1498 }
1500 /* Find all the ABI tags in the attribute list ATTR and either call
1501 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1503 static void
1505 {
1512 {
1517 else
1519 }
1520 }
1522 /* Find all the ABI tags on T and its enclosing scopes and either call
1523 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1525 static void
1527 {
1529 {
1530 tree attr;
1532 {
1535 }
1536 else
1537 {
1540 }
1542 }
1543 }
1545 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1546 types with ABI tags, add the corresponding identifiers to the VEC in
1547 *DATA and set IDENTIFIER_MARKED. */
1549 static tree
1551 {
1553 /* Tell cp_walk_subtrees to look though typedefs. [PR98481] */
1559 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1560 anyway, but let's make sure of it. */
1568 }
1570 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1571 IDENTIFIER_MARKED on its ABI tags. */
1573 static tree
1575 {
1577 /* Tell cp_walk_subtrees to look though typedefs. */
1583 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1584 anyway, but let's make sure of it. */
1592 }
1594 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1595 scopes. */
1597 static void
1599 {
1602 {
1605 {
1606 /* Template arguments are part of the signature. */
1609 {
1612 }
1613 }
1615 /* A function's parameter types are part of the signature, so
1616 we don't need to inherit any tags that are also in them. */
1621 }
1622 }
1624 /* Check that T has all the ABI tags that subobject SUBOB has, or
1625 warn if not. If T is a (variable or function) declaration, also
1626 return any missing tags, and add them to T if JUST_CHECKING is false. */
1628 static tree
1630 {
1638 /* No need to worry about things local to this TU. */
1654 {
1657 }
1658 else
1659 {
1663 else
1666 }
1671 }
1673 /* Check that DECL has all the ABI tags that are used in parts of its type
1674 that are not reflected in its mangled name. */
1676 void
1678 {
1685 }
1687 /* Return any ABI tags that are used in parts of the type of DECL
1688 that are not reflected in its mangled name. This function is only
1689 used in backward-compatible mangling for ABI <11. */
1691 tree
1693 {
1697 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1698 that we can use this function for setting need_abi_warning
1699 regardless of the current flag_abi_version. */
1702 else
1704 }
1706 void
1708 {
1718 {
1721 {
1725 }
1726 }
1728 // If we found some tags on our template arguments, add them to our
1729 // abi_tag attribute.
1731 {
1735 else
1738 }
1741 }
1743 /* Return true, iff class T has a non-virtual destructor that is
1744 accessible from outside the class heirarchy (i.e. is public, or
1745 there's a suitable friend. */
1747 static bool
1749 {
1752 /* An implicitly declared destructor is always public. And,
1753 if it were virtual, we would have created it by now. */
1768 }
1770 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1771 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1772 properties of the bases. */
1774 static void
1778 {
1782 tree base_binfo;
1783 tree binfo;
1793 {
1802 /* If any base class is non-literal, so is the derived class. */
1806 /* If the base class doesn't have copy constructors or
1807 assignment operators that take const references, then the
1808 derived class cannot have such a member automatically
1809 generated. */
1818 /* A virtual base does not effect nearly emptiness. */
1819 ;
1821 {
1823 /* And if there is more than one nearly empty base, then the
1824 derived class is not nearly empty either. */
1826 else
1827 /* Remember we've seen one. */
1829 }
1831 /* If the base class is not empty or nearly empty, then this
1832 class cannot be nearly empty. */
1835 /* A lot of properties from the bases also apply to the derived
1836 class. */
1853 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1856 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1862 /* A standard-layout class is a class that:
1863 ...
1864 * has no non-standard-layout base classes, */
1867 {
1868 tree basefield;
1869 /* ...has no base classes of the same type as the first non-static
1870 data member... */
1872 && (same_type_ignoring_top_level_qualifiers_p
1875 /* DR 1813:
1876 ...has at most one base class subobject of any given type... */
1879 else
1880 /* ...has all non-static data members and bit-fields in the class
1881 and its base classes first declared in the same class. */
1887 {
1890 else
1893 }
1894 }
1896 /* Don't bother collecting tm attributes if transactional memory
1897 support is not enabled. */
1899 {
1903 }
1906 }
1908 /* If one of the base classes had TM attributes, and the current class
1909 doesn't define its own, then the current class inherits one. */
1911 {
1914 }
1915 }
1917 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1918 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1919 that have had a nearly-empty virtual primary base stolen by some
1920 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1921 T. */
1923 static void
1925 {
1929 tree base_binfo;
1931 /* Determine the primary bases of our bases. */
1934 {
1937 /* See if we're the non-virtual primary of our inheritance
1938 chain. */
1940 {
1947 /* We are the primary binfo. */
1949 }
1950 /* Determine if we have a virtual primary base, and mark it so.
1951 */
1953 {
1957 /* Someone already claimed this base. */
1959 else
1960 {
1961 tree delta;
1966 /* A virtual binfo might have been copied from within
1967 another hierarchy. As we're about to use it as a
1968 primary base, make sure the offsets match. */
1976 }
1977 }
1978 }
1980 /* First look for a dynamic direct non-virtual base. */
1982 {
1986 {
1989 }
1990 }
1992 /* A "nearly-empty" virtual base class can be the primary base
1993 class, if no non-virtual polymorphic base can be found. Look for
1994 a nearly-empty virtual dynamic base that is not already a primary
1995 base of something in the hierarchy. If there is no such base,
1996 just pick the first nearly-empty virtual base. */
2002 {
2004 {
2005 /* Found one that is not primary. */
2008 }
2010 /* Remember the first candidate. */
2012 }
2014 found:
2015 /* If we've got a primary base, use it. */
2017 {
2022 /* We are stealing a primary base. */
2026 {
2027 tree delta;
2030 /* A virtual binfo might have been copied from within
2031 another hierarchy. As we're about to use it as a primary
2032 base, make sure the offsets match. */
2037 }
2044 }
2045 }
2047 /* Update the variant types of T. */
2049 void
2051 {
2056 variant;
2058 {
2059 /* These fields are in the _TYPE part of the node, not in
2060 the TYPE_LANG_SPECIFIC component, so they are not shared. */
2071 /* Copy whatever these are holding today. */
2081 {
2084 }
2089 }
2090 }
2092 /* KLASS is a class that we're applying may_alias to after the body is
2093 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
2094 canonical type(s) will be implicitly updated. */
2096 static void
2098 {
2107 }
2109 /* Early variant fixups: we apply attributes at the beginning of the class
2110 definition, and we need to fix up any variants that have already been
2111 made via elaborated-type-specifier so that check_qualified_type works. */
2113 void
2115 {
2116 tree variants;
2131 variants;
2133 {
2134 /* These are the two fields that check_qualified_type looks at and
2135 are affected by attributes. */
2140 else
2146 }
2147 }
2148 \f
2149 /* Set memoizing fields and bits of T (and its variants) for later
2150 use. */
2152 static void
2154 {
2155 /* Fix up variants (if any). */
2159 /* For a class w/o baseclasses, 'finish_struct' has set
2160 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2161 Similarly for a class whose base classes do not have vtables.
2162 When neither of these is true, we might have removed abstract
2163 virtuals (by providing a definition), added some (by declaring
2164 new ones), or redeclared ones from a base class. We need to
2165 recalculate what's really an abstract virtual at this point (by
2166 looking in the vtables). */
2169 /* If this type has a copy constructor or a destructor, force its
2170 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2171 nonzero. This will cause it to be passed by invisible reference
2172 and prevent it from being returned in a register. */
2175 {
2176 tree variants;
2179 {
2182 }
2183 }
2184 }
2186 /* Issue warnings about T having private constructors, but no friends,
2187 and so forth.
2189 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2190 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2191 non-private static member functions. */
2193 static void
2195 {
2201 /* If the class has friends, those entities might create and
2202 access instances, so we should not warn. */
2205 /* We will have warned when the template was declared; there's
2206 no need to warn on every instantiation. */
2208 /* There's no reason to even consider warning about this
2209 class. */
2212 /* We only issue one warning, if more than one applies, because
2213 otherwise, on code like:
2215 class A {
2216 // Oops - forgot `public:'
2217 A();
2218 A(const A&);
2219 ~A();
2220 };
2222 we warn several times about essentially the same problem. */
2224 /* Check to see if all (non-constructor, non-destructor) member
2225 functions are private. (Since there are no friends or
2226 non-private statics, we can't ever call any of the private member
2227 functions.) */
2236 /* We're not interested in compiler-generated methods; they don't
2239 {
2241 /* A non-private static member function is just like a
2242 friend; it can create and invoke private member
2243 functions, and be accessed without a class
2244 instance. */
2248 /* Keep searching for a static member function. */
2249 }
2254 {
2255 /* There are no non-private methods, and there's at least one
2256 private member function that isn't a constructor or
2257 destructor. (If all the private members are
2258 constructors/destructors we want to use the code below that
2259 issues error messages specifically referring to
2260 constructors/destructors.) */
2266 {
2269 }
2271 {
2275 }
2276 }
2278 /* Even if some of the member functions are non-private, the class
2279 won't be useful for much if all the constructors or destructors
2280 are private: such an object can never be created or destroyed. */
2283 {
2286 t);
2288 }
2290 /* Warn about classes that have private constructors and no friends. */
2292 /* Implicitly generated constructors are always public. */
2294 {
2297 /* If a non-template class does not define a copy
2298 constructor, one is defined for it, enabling it to avoid
2299 this warning. For a template class, this does not
2300 happen, and so we would normally get a warning on:
2302 template <class T> class C { private: C(); };
2304 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2305 complete non-template or fully instantiated classes have this
2306 flag set. */
2309 else
2314 /* Ideally, we wouldn't count any constructor that takes
2315 an argument of the class type as a parameter, because
2316 such things cannot be used to construct an instance of
2317 the class unless you already have one. */
2319 else
2320 {
2323 }
2326 {
2328 "%q#T only defines private constructors and has "
2335 }
2336 }
2337 }
2339 /* Make BINFO's vtable have N entries, including RTTI entries,
2340 vbase and vcall offsets, etc. Set its type and call the back end
2341 to lay it out. */
2343 static void
2345 {
2346 tree atype;
2347 tree vtable;
2352 /* We may have to grow the vtable. */
2355 {
2359 }
2360 }
2362 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2363 have the same signature. */
2365 int
2367 {
2368 /* One destructor overrides another if they are the same kind of
2369 destructor. */
2373 /* But a non-destructor never overrides a destructor, nor vice
2374 versa, nor do different kinds of destructors override
2375 one-another. For example, a complete object destructor does not
2376 override a deleting destructor. */
2385 {
2393 }
2395 }
2397 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2398 subobject. */
2400 static bool
2402 {
2403 tree probe;
2406 {
2410 /* If we meet a virtual base, we can't follow the inheritance
2411 any more. See if the complete type of DERIVED contains
2412 such a virtual base. */
2415 }
2417 }
2420 /* The function for which we are trying to find a final overrider. */
2421 tree fn;
2422 /* The base class in which the function was declared. */
2423 tree declaring_base;
2424 /* The candidate overriders. */
2425 tree candidates;
2426 /* Path to most derived. */
2428 };
2430 /* Add the overrider along the current path to FFOD->CANDIDATES.
2431 Returns true if an overrider was found; false otherwise. */
2433 static bool
2437 {
2438 tree method;
2440 /* If BINFO is not the most derived type, try a more derived class.
2441 A definition there will overrider a definition here. */
2443 {
2444 depth--;
2448 }
2452 {
2455 /* Remove any candidates overridden by this new function. */
2457 {
2458 /* If *CANDIDATE overrides METHOD, then METHOD
2459 cannot override anything else on the list. */
2462 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2465 else
2467 }
2469 /* Add the new function. */
2472 }
2475 }
2477 /* Called from find_final_overrider via dfs_walk. */
2479 static tree
2481 {
2489 }
2491 static tree
2493 {
2498 }
2500 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2501 FN and whose TREE_VALUE is the binfo for the base where the
2502 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2503 DERIVED) is the base object in which FN is declared. */
2505 static tree
2507 {
2508 find_final_overrider_data ffod;
2510 /* Getting this right is a little tricky. This is valid:
2512 struct S { virtual void f (); };
2513 struct T { virtual void f (); };
2514 struct U : public S, public T { };
2516 even though calling `f' in `U' is ambiguous. But,
2518 struct R { virtual void f(); };
2519 struct S : virtual public R { virtual void f (); };
2520 struct T : virtual public R { virtual void f (); };
2521 struct U : public S, public T { };
2523 is not -- there's no way to decide whether to put `S::f' or
2524 `T::f' in the vtable for `R'.
2526 The solution is to look at all paths to BINFO. If we find
2527 different overriders along any two, then there is a problem. */
2531 /* Determine the depth of the hierarchy. */
2540 /* If there was no winner, issue an error message. */
2545 }
2547 /* Return the index of the vcall offset for FN when TYPE is used as a
2548 virtual base. */
2550 static tree
2552 {
2554 tree_pair_p p;
2562 /* There should always be an appropriate index. */
2564 }
2566 /* Given a DECL_VINDEX of a virtual function found in BINFO, return the final
2567 overrider at that index in the vtable. This should only be used when we
2568 know that BINFO is correct for the dynamic type of the object. */
2570 tree
2572 {
2577 /* BINFO_VIRTUALS in a primary base isn't accurate, find the derived
2578 class that actually owns the vtable. */
2582 }
2584 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2585 dominated by T. FN is the old function; VIRTUALS points to the
2586 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2587 of that entry in the list. */
2589 static void
2592 {
2593 tree b;
2594 tree overrider;
2595 tree delta;
2596 tree virtual_base;
2597 tree first_defn;
2603 /* Find the nearest primary base (possibly binfo itself) which defines
2604 this function; this is the class the caller will convert to when
2605 calling FN through BINFO. */
2607 {
2612 /* The nearest definition is from a lost primary. */
2615 }
2618 /* Find the final overrider. */
2621 {
2624 }
2627 /* Check for adjusting covariant return types. */
2635 /* If the overrider is invalid, don't even try. */
2637 {
2638 /* If FN is a covariant thunk, we must figure out the adjustment
2639 to the final base FN was converting to. As OVERRIDER_TARGET might
2640 also be converting to the return type of FN, we have to
2641 combine the two conversions here. */
2648 {
2652 }
2653 else
2657 /* Find the equivalent binfo within the return type of the
2658 overriding function. We will want the vbase offset from
2659 there. */
2661 over_return);
2664 {
2665 /* There was no existing virtual thunk (which takes
2666 precedence). So find the binfo of the base function's
2667 return type within the overriding function's return type.
2668 Fortunately we know the covariancy is valid (it
2669 has already been checked), so we can just iterate along
2670 the binfos, which have been chained in inheritance graph
2671 order. Of course it is lame that we have to repeat the
2672 search here anyway -- we should really be caching pieces
2673 of the vtable and avoiding this repeated work. */
2677 /* Find the base binfo within the overriding function's
2678 return type. We will always find a thunk_binfo, except
2679 when the covariancy is invalid (which we will have
2680 already diagnosed). */
2689 /* See if virtual inheritance is involved. */
2691 virtual_offset;
2698 {
2702 {
2703 /* We convert via virtual base. Adjust the fixed
2704 offset to be from there. */
2705 offset =
2709 }
2711 /* There was an existing fixed offset, this must be
2712 from the base just converted to, and the base the
2713 FN was thunking to. */
2715 else
2717 }
2718 }
2721 /* Replace the overriding function with a covariant thunk. We
2722 will emit the overriding function in its own slot as
2723 well. */
2726 }
2727 else
2731 /* If we need a covariant thunk, then we may need to adjust first_defn.
2732 The ABI specifies that the thunks emitted with a function are
2733 determined by which bases the function overrides, so we need to be
2734 sure that we're using a thunk for some overridden base; even if we
2735 know that the necessary this adjustment is zero, there may not be an
2736 appropriate zero-this-adjustment thunk for us to use since thunks for
2737 overriding virtual bases always use the vcall offset.
2739 Furthermore, just choosing any base that overrides this function isn't
2740 quite right, as this slot won't be used for calls through a type that
2741 puts a covariant thunk here. Calling the function through such a type
2742 will use a different slot, and that slot is the one that determines
2743 the thunk emitted for that base.
2745 So, keep looking until we find the base that we're really overriding
2746 in this slot: the nearest primary base that doesn't use a covariant
2747 thunk in this slot. */
2749 {
2751 /* We already know that the overrider needs a covariant thunk. */
2754 {
2761 }
2763 }
2765 /* Assume that we will produce a thunk that convert all the way to
2766 the final overrider, and not to an intermediate virtual base. */
2769 /* See if we can convert to an intermediate virtual base first, and then
2770 use the vcall offset located there to finish the conversion. */
2772 {
2773 /* If we find the final overrider, then we can stop
2774 walking. */
2779 /* If we find a virtual base, and we haven't yet found the
2780 overrider, then there is a virtual base between the
2781 declaring base (first_defn) and the final overrider. */
2783 {
2786 }
2787 }
2789 /* Compute the constant adjustment to the `this' pointer. The
2790 `this' pointer, when this function is called, will point at BINFO
2791 (or one of its primary bases, which are at the same offset). */
2793 /* The `this' pointer needs to be adjusted from the declaration to
2794 the nearest virtual base. */
2799 /* If the nearest definition is in a lost primary, we don't need an
2800 entry in our vtable. Except possibly in a constructor vtable,
2801 if we happen to get our primary back. In that case, the offset
2802 will be zero, as it will be a primary base. */
2804 else
2805 /* The `this' pointer needs to be adjusted from pointing to
2806 BINFO to pointing at the base where the final overrider
2807 appears. */
2818 else
2822 }
2824 /* Called from modify_all_vtables via dfs_walk. */
2826 static tree
2828 {
2830 tree virtuals;
2831 tree old_virtuals;
2835 /* A base without a vtable needs no modification, and its bases
2836 are uninteresting. */
2841 /* Don't do the primary vtable, if it's new. */
2845 /* There's no need to modify the vtable for a non-virtual primary
2846 base; we're not going to use that vtable anyhow. We do still
2847 need to do this for virtual primary bases, as they could become
2848 non-primary in a construction vtable. */
2853 /* Now, go through each of the virtual functions in the virtual
2854 function table for BINFO. Find the final overrider, and update
2855 the BINFO_VIRTUALS list appropriately. */
2858 virtuals;
2862 binfo,
2867 }
2869 /* Update all of the primary and secondary vtables for T. Create new
2870 vtables as required, and initialize their RTTI information. Each
2871 of the functions in VIRTUALS is declared in T and may override a
2872 virtual function from a base class; find and modify the appropriate
2873 entries to point to the overriding functions. Returns a list, in
2874 declaration order, of the virtual functions that are declared in T,
2875 but do not appear in the primary base class vtable, and which
2876 should therefore be appended to the end of the vtable for T. */
2878 static tree
2880 {
2884 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2888 /* Update all of the vtables. */
2891 /* Add virtual functions not already in our primary vtable. These
2892 will be both those introduced by this class, and those overridden
2893 from secondary bases. It does not include virtuals merely
2894 inherited from secondary bases. */
2896 {
2901 {
2902 /* We don't need to adjust the `this' pointer when
2903 calling this function. */
2907 /* This is a function not already in our vtable. Keep it. */
2909 }
2910 else
2911 /* We've already got an entry for this function. Skip it. */
2913 }
2916 }
2918 /* Get the base virtual function declarations in T that have the
2919 indicated NAME. */
2921 static void
2923 {
2926 /* Find virtual functions in T with the indicated NAME. */
2928 {
2930 {
2933 }
2934 }
2941 {
2944 }
2945 }
2947 /* If this method overrides a virtual method from a base, then mark
2948 this member function as being virtual as well. Do 'final' and
2949 'override' checks too. */
2951 void
2953 {
2955 /* In [temp.mem] we have:
2957 A specialization of a member function template does not
2958 override a virtual function from a base class. */
2961 /* IDENTIFIER_VIRTUAL_P indicates whether the name has ever been
2962 used for a vfunc. That avoids the expensive look_for_overrides
2963 call that when we know there's nothing to find. As conversion
2964 operators for the same type can have distinct identifiers, we
2965 cannot optimize those in that way. */
2969 /* Check staticness after we've checked if we 'override'. */
2971 {
2972 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2973 the error_mark_node so that we know it is an overriding
2974 function. */
2983 }
2988 {
2989 /* Remember this identifier is virtual name. */
2993 /* It's a new vfunc. */
2998 }
3001 }
3003 /* Warn about hidden virtual functions that are not overridden in t.
3004 We know that constructors and destructors don't apply. */
3006 static void
3008 {
3011 {
3019 tree base_binfo;
3020 tree binfo;
3026 /* Iterate through all of the base classes looking for possibly
3027 hidden functions. */
3030 {
3033 }
3035 /* If there are no functions to hide, continue. */
3039 /* Remove any overridden functions. */
3042 {
3046 {
3047 /* If the method from the base class has the same
3048 signature as the method from the derived class, it
3049 has been overridden. Note that we can't move on
3050 after finding one match: fndecl might override
3051 multiple base fns. */
3055 {
3058 }
3059 }
3062 }
3065 /* All the derived fns override base virtuals. */
3068 /* Now give a warning for all base functions without overriders,
3069 as they are hidden. */
3072 {
3073 auto_diagnostic_group d;
3074 /* Here we know it is a hider, and no overrider exists. */
3076 OPT_Woverloaded_virtual_,
3079 }
3080 }
3081 }
3083 /* Recursive helper for finish_struct_anon. */
3085 static void
3087 {
3089 {
3090 /* We're generally only interested in entities the user
3091 declared, but we also find nested classes by noticing
3092 the TYPE_DECL that we create implicitly. You're
3093 allowed to put one anonymous union inside another,
3094 though, so we explicitly tolerate that. We use
3095 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
3096 we also allow unnamed types used for defining fields. */
3105 /* Recurse into the anonymous aggregates to correctly handle
3106 access control (c++/24926):
3108 class A {
3109 union {
3110 union {
3111 int i;
3112 };
3113 };
3114 };
3116 int j=A().i; */
3120 }
3121 }
3123 /* Fix up any anonymous union/struct members of T. */
3125 static void
3127 {
3129 {
3138 }
3139 }
3141 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
3142 will be used later during class template instantiation.
3143 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
3144 a non-static member data (FIELD_DECL), a member function
3145 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
3146 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
3147 When FRIEND_P is nonzero, T is either a friend class
3148 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
3149 (FUNCTION_DECL, TEMPLATE_DECL). */
3151 void
3153 {
3156 {
3161 }
3162 }
3164 /* This function is called from declare_virt_assop_and_dtor via
3165 dfs_walk_all.
3167 DATA is a type that direcly or indirectly inherits the base
3168 represented by BINFO. If BINFO contains a virtual assignment [copy
3169 assignment or move assigment] operator or a virtual constructor,
3170 declare that function in DATA if it hasn't been already declared. */
3172 static tree
3174 {
3182 /* A base without a vtable needs no modification, and its bases
3183 are uninteresting. */
3187 /* If this is a primary base, then we have already looked at the
3188 virtual functions of its vtable. */
3192 {
3196 {
3201 }
3205 }
3208 }
3210 /* If the class type T has a direct or indirect base that contains a
3211 virtual assignment operator or a virtual destructor, declare that
3212 function in T if it hasn't been already declared. */
3214 static void
3216 {
3224 dfs_declare_virt_assop_and_dtor,
3226 }
3228 /* Declare the inheriting constructor for class T inherited from base
3229 constructor CTOR with the parameter array PARMS of size NPARMS. */
3231 static void
3233 {
3236 /* We don't declare an inheriting ctor that would be a default,
3237 copy or move ctor for derived or base. */
3242 {
3246 }
3255 {
3258 }
3259 }
3261 /* Declare all the inheriting constructors for class T inherited from base
3262 constructor CTOR. */
3264 static void
3266 {
3270 {
3275 }
3280 {
3284 }
3287 {
3288 auto_diagnostic_group d;
3292 }
3293 }
3295 /* Implicitly declare T(). */
3297 static void
3299 {
3304 /* Don't force the declaration to get a hard answer; if the
3305 definition would have made the class non-literal, it will still be
3306 non-literal because of the base or member in question, and that
3307 gives a better diagnostic. */
3309 }
3311 /* Create default constructors, assignment operators, and so forth for
3312 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3313 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3314 the class cannot have a default constructor, copy constructor
3315 taking a const reference argument, or an assignment operator taking
3316 a const reference, respectively. */
3318 static void
3322 {
3323 /* Destructor. */
3325 /* In general, we create destructors lazily. */
3334 /* [class.ctor]
3336 If there is no user-declared constructor for a class, a default
3337 constructor is implicitly declared. */
3341 /* [class.ctor]
3343 If a class definition does not explicitly declare a copy
3344 constructor, one is declared implicitly. */
3346 {
3352 }
3354 /* If there is no assignment operator, one will be created if and
3355 when it is needed. For now, just record whether or not the type
3356 of the parameter to the assignment operator will be a const or
3357 non-const reference. */
3359 {
3365 }
3367 /* We can't be lazy about declaring functions that might override
3368 a virtual function from a base class. */
3371 /* If the class definition does not explicitly declare an == operator
3372 function, but declares a defaulted three-way comparison operator function,
3373 an == operator function is declared implicitly. */
3376 {
3378 NULL_TREE);
3383 else
3384 {
3388 }
3390 }
3393 {
3397 {
3398 /* declare, then remove the decl */
3403 {
3405 /* CWG2799: Inheriting a default constructor gives us a default
3406 constructor, not just an inherited constructor. */
3409 }
3412 }
3413 else
3415 }
3416 }
3418 /* Cache of enum_min_precision values. */
3421 /* Return the minimum precision of a bit-field needed to store all
3422 enumerators of ENUMERAL_TYPE TYPE. */
3424 static int
3426 {
3428 /* For unscoped enums without fixed underlying type and without mode
3429 attribute we can just use precision of the underlying type. */
3445 {
3449 {
3460 }
3461 }
3462 else
3470 }
3472 /* FIELD is a bit-field. We are finishing the processing for its
3473 enclosing type. Issue any appropriate messages and set appropriate
3474 flags. Returns false if an error has been diagnosed. */
3476 static bool
3478 {
3480 tree w;
3482 /* Extract the declared width of the bitfield, which has been
3483 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3486 /* Remove the bit-field width indicator so that the rest of the
3487 compiler does not treat that value as a qualifier. */
3490 /* Detect invalid bit-field type. */
3492 {
3496 }
3497 else
3498 {
3500 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3503 /* detect invalid field size. */
3509 {
3512 }
3514 {
3517 }
3519 {
3522 }
3532 {
3538 }
3539 }
3542 {
3546 }
3547 else
3548 {
3549 /* Non-bit-fields are aligned for their type. */
3553 }
3554 }
3556 /* FIELD is a non bit-field. We are finishing the processing for its
3557 enclosing type T. Issue any appropriate messages and set appropriate
3558 flags. */
3560 static bool
3562 tree t,
3565 {
3569 /* In C++98 an anonymous union cannot contain any fields which would change
3570 the settings of CANT_HAVE_CONST_CTOR and friends. */
3572 ;
3573 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3574 structs. So, we recurse through their fields here. */
3576 {
3581 cant_have_const_ctor,
3582 no_const_asn_ref);
3583 }
3584 /* Check members with class type for constructors, destructors,
3585 etc. */
3587 {
3588 /* Never let anything with uninheritable virtuals
3589 make it through without complaint. */
3593 {
3598 field);
3603 field);
3605 {
3609 }
3610 }
3611 else
3612 {
3625 }
3634 }
3639 /* `build_class_init_list' does not recognize
3640 non-FIELD_DECLs. */
3644 }
3646 /* Check the data members (both static and non-static), class-scoped
3647 typedefs, etc., appearing in the declaration of T. Issue
3648 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3649 declaration order) of access declarations; each TREE_VALUE in this
3650 list is a USING_DECL.
3652 In addition, set the following flags:
3654 EMPTY_P
3655 The class is empty, i.e., contains no non-static data members.
3657 CANT_HAVE_CONST_CTOR_P
3658 This class cannot have an implicitly generated copy constructor
3659 taking a const reference.
3661 CANT_HAVE_CONST_ASN_REF
3662 This class cannot have an implicitly generated assignment
3663 operator taking a const reference.
3665 All of these flags should be initialized before calling this
3666 function. */
3668 static void
3672 {
3675 /* Assume there are no access declarations. */
3677 /* Effective C has things to say about classes with pointer members. */
3679 /* Default initialized members affect the whole class. */
3681 /* Lack of any non-static data member of non-volatile literal
3682 type affects a union. */
3684 /* Standard layout requires all FIELDS have same access. */
3688 {
3692 {
3697 /* Save the access declarations for our caller. */
3706 /* FIXME: We should fold in the checking from check_methods. */
3716 {
3717 /* [class.union]
3719 (C++98) If a union contains a static data member,
3720 ... the program is ill-formed. */
3724 }
3729 {
3730 /* [class.union]
3732 If a union contains ... or a [non-static data] member
3733 of reference type, the program is ill-formed. */
3737 }
3739 data_member:
3740 /* Common VAR_DECL & FIELD_DECL processing. */
3744 /* Template instantiation can cause this. Perhaps this
3745 should be a specific instantiation check? */
3747 {
3751 }
3753 {
3757 }
3760 }
3768 /* If it is not a union and at least one non-static data member is
3769 non-literal, the whole class becomes non-literal. Per Core/1453,
3770 volatile non-static data members and base classes are also not allowed.
3771 If it is a union, we might set CLASSTYPE_LITERAL_P after we've seen all
3772 members.
3773 Note: if the type is incomplete we will complain later on. */
3775 {
3778 else
3780 }
3785 {
3786 /* A standard-layout class is a class that:
3788 ... has the same access control (Clause 11) for all
3789 non-static data members, */
3792 else
3795 /* Aggregates must be public. */
3798 }
3800 /* If this is of reference type, check if it needs an init. */
3802 {
3808 {
3809 /* ARM $12.6.2: [A member initializer list] (or, for an
3810 aggregate, initialization by a brace-enclosed list) is the
3811 only way to initialize non-static const and reference
3812 members. */
3815 }
3816 }
3821 {
3823 {
3825 "ignoring packed attribute because of"
3828 }
3832 }
3836 /* We don't treat zero-width bitfields as making a class
3837 non-empty. */
3838 ;
3841 /* Empty data members also don't make a class non-empty. */
3843 else
3844 {
3845 /* The class is non-empty. */
3847 /* The class is not even nearly empty. */
3849 /* If one of the data members contains an empty class, so
3850 does T. */
3854 }
3856 /* This is used by -Weffc++ (see below). Warn only for pointers
3857 to members which might hold dynamic memory. So do not warn
3858 for pointers to functions or pointers to members. */
3864 {
3869 }
3875 {
3882 }
3885 /* DR 148 now allows pointers to members (which are POD themselves),
3886 to be allowed in POD structs. */
3890 /* A potentially-overlapping non-static data member makes the class
3891 non-layout-POD. */
3900 /* We set DECL_C_BIT_FIELD in grokbitfield.
3901 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3907 {
3910 {
3914 default_init_member);
3915 }
3917 }
3919 /* Now that we've removed bit-field widths from DECL_INITIAL,
3920 anything left in DECL_INITIAL is an NSDMI that makes the class
3921 non-aggregate in C++11, and non-layout-POD always. */
3923 {
3926 else
3928 }
3931 {
3932 /* If any field is const, the structure type is pseudo-const. */
3937 {
3938 /* ARM $12.6.2: [A member initializer list] (or, for an
3939 aggregate, initialization by a brace-enclosed list) is the
3940 only way to initialize non-static const and reference
3941 members. */
3944 }
3945 }
3946 /* A field that is pseudo-const makes the structure likewise. */
3948 {
3953 }
3955 /* Core issue 80: A non-static data member is required to have a
3956 different name from the class iff the class has a
3957 user-declared constructor. */
3962 }
3964 /* Per CWG 2096, a type is a literal type if it is a union, and at least
3965 one of its non-static data members is of non-volatile literal type. */
3969 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3970 it should also define a copy constructor and an assignment operator to
3971 implement the correct copy semantic (deep vs shallow, etc.). As it is
3972 not feasible to check whether the constructors do allocate dynamic memory
3973 and store it within members, we approximate the warning like this:
3975 -- Warn only if there are members which are pointers
3976 -- Warn only if there is a non-trivial constructor (otherwise,
3977 there cannot be memory allocated).
3978 -- Warn only if there is a non-trivial destructor. We assume that the
3979 user at least implemented the cleanup correctly, and a destructor
3980 is needed to free dynamic memory.
3982 This seems enough for practical purposes. */
3984 && pointer_member
3988 {
3990 {
3992 {
3997 }
4003 }
4004 }
4006 /* Non-static data member initializers make the default constructor
4007 non-trivial. */
4009 {
4012 }
4014 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
4018 /* Check anonymous struct/anonymous union fields. */
4021 /* We've built up the list of access declarations in reverse order.
4022 Fix that now. */
4024 }
4026 /* If TYPE is an empty class type, records its OFFSET in the table of
4027 OFFSETS. */
4029 static int
4031 {
4032 splay_tree_node n;
4037 /* Record the location of this empty object in OFFSETS. */
4045 type,
4049 }
4051 /* Returns nonzero if TYPE is an empty class type and there is
4052 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
4054 static int
4056 {
4057 splay_tree_node n;
4058 tree t;
4063 /* Record the location of this empty object in OFFSETS. */
4073 {
4081 {
4085 }
4086 }
4089 {
4094 }
4097 }
4099 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
4100 F for every subobject, passing it the type, offset, and table of
4101 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
4102 be traversed.
4104 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
4105 than MAX_OFFSET will not be walked.
4107 If F returns a nonzero value, the traversal ceases, and that value
4108 is returned. Otherwise, returns zero. */
4110 static int
4112 subobject_offset_fn f,
4113 tree offset,
4114 splay_tree offsets,
4115 tree max_offset,
4117 {
4121 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
4122 stop. */
4130 {
4133 }
4136 {
4137 tree field;
4138 tree binfo;
4141 /* Avoid recursing into objects that are not interesting. */
4145 /* Record the location of TYPE. */
4150 /* Iterate through the direct base classes of TYPE. */
4154 {
4155 tree binfo_offset;
4160 tree orig_binfo;
4161 /* We cannot rely on BINFO_OFFSET being set for the base
4162 class yet, but the offsets for direct non-virtual
4163 bases can be calculated by going back to the TYPE. */
4166 offset,
4170 f,
4171 binfo_offset,
4172 offsets,
4173 max_offset,
4177 }
4180 {
4184 /* Iterate through the virtual base classes of TYPE. In G++
4185 3.2, we included virtual bases in the direct base class
4186 loop above, which results in incorrect results; the
4187 correct offsets for virtual bases are only known when
4188 working with the most derived type. */
4192 {
4194 f,
4196 offset,
4198 offsets,
4199 max_offset,
4203 }
4204 else
4205 {
4206 /* We still have to walk the primary base, if it is
4207 virtual. (If it is non-virtual, then it was walked
4208 above.) */
4214 {
4215 r = (walk_subobject_offsets
4220 }
4221 }
4222 }
4224 /* Iterate through the fields of TYPE. */
4229 {
4230 tree field_offset;
4235 f,
4237 offset,
4238 field_offset),
4239 offsets,
4240 max_offset,
4244 }
4245 }
4247 {
4250 tree index;
4252 /* Avoid recursing into objects that are not interesting. */
4255 || !domain
4259 /* Step through each of the elements in the array. */
4263 {
4265 f,
4266 offset,
4267 offsets,
4268 max_offset,
4274 /* If this new OFFSET is bigger than the MAX_OFFSET, then
4275 there's no point in iterating through the remaining
4276 elements of the array. */
4279 }
4280 }
4283 }
4285 /* Return true iff FIELD_DECL DECL is potentially overlapping. */
4287 static bool
4289 {
4290 /* Base fields are actually potentially overlapping, but C++ bases go through
4291 a different code path based on binfos, and ObjC++ base fields are laid out
4292 in objc-act, so we don't want layout_class_type to mess with them. */
4294 {
4297 }
4301 }
4303 /* Return true iff DECL is an empty field, either for an empty base or a
4304 [[no_unique_address]] data member. */
4306 bool
4308 {
4316 /* Empty fields should have size zero. */
4320 }
4322 /* Record all of the empty subobjects of DECL_OR_BINFO. */
4324 static void
4326 splay_tree offsets)
4327 {
4332 {
4338 }
4339 else
4340 {
4345 }
4347 tree max_offset;
4348 /* If recording subobjects for a non-static data member or a
4349 non-empty base class, we do not need to record offsets beyond
4350 the size of the biggest empty class. Additional data members
4351 will go at the end of the class. Additional base classes will go
4352 either at offset zero (if empty, in which case they cannot
4353 overlap with offsets past the size of the biggest empty class) or
4354 at the end of the class.
4356 However, if we are placing an empty base class, then we must record
4357 all offsets, as either the empty class is at offset zero (where
4358 other empty classes might later be placed) or at the end of the
4359 class (where other objects might then be placed, so other empty
4360 subobjects might later overlap). */
4364 else
4368 }
4370 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4371 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4372 virtual bases of TYPE are examined. */
4374 static int
4376 tree offset,
4377 splay_tree offsets,
4379 {
4380 splay_tree_node max_node;
4382 /* Get the node in OFFSETS that indicates the maximum offset where
4383 an empty subobject is located. */
4385 /* If there aren't any empty subobjects, then there's no point in
4386 performing this check. */
4392 vbases_p);
4393 }
4395 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4396 non-static data member of the type indicated by RLI. BINFO is the
4397 binfo corresponding to the base subobject, OFFSETS maps offsets to
4398 types already located at those offsets. This function determines
4399 the position of the DECL. */
4401 static void
4403 tree decl,
4404 tree binfo,
4405 splay_tree offsets)
4406 {
4409 tree type;
4412 {
4413 /* For the purposes of determining layout conflicts, we want to
4414 use the class type of BINFO; TREE_TYPE (DECL) will be the
4415 CLASSTYPE_AS_BASE version, which does not contain entries for
4416 zero-sized bases. */
4419 }
4420 else
4421 {
4424 }
4426 /* Try to place the field. It may take more than one try if we have
4427 a hard time placing the field without putting two objects of the
4428 same type at the same address. */
4430 {
4433 /* Place this field. */
4437 /* We have to check to see whether or not there is already
4438 something of the same type at the offset we're about to use.
4439 For example, consider:
4441 struct S {};
4442 struct T : public S { int i; };
4443 struct U : public S, public T {};
4445 Here, we put S at offset zero in U. Then, we can't put T at
4446 offset zero -- its S component would be at the same address
4447 as the S we already allocated. So, we have to skip ahead.
4448 Since all data members, including those whose type is an
4449 empty class, have nonzero size, any overlap can happen only
4450 with a direct or indirect base-class -- it can't happen with
4451 a data member. */
4452 /* In a union, overlap is permitted; all members are placed at
4453 offset zero. */
4458 {
4459 /* Strip off the size allocated to this field. That puts us
4460 at the first place we could have put the field with
4461 proper alignment. */
4464 /* Bump up by the alignment required for the type. */
4465 rli->bitpos
4471 }
4474 {
4475 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4476 the offset wasn't aligned like a pointer when we started to
4477 layout this field, that affects its position. */
4480 {
4483 "alignment of %qD increased in %<-fabi-version=9%> "
4485 else
4488 decl);
4489 }
4491 }
4492 else
4493 /* There was no conflict. We're done laying out this field. */
4495 }
4497 /* Now that we know where it will be placed, update its
4498 BINFO_OFFSET. */
4500 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4501 this point because their BINFO_OFFSET is copied from another
4502 hierarchy. Therefore, we may not need to add the entire
4503 OFFSET. */
4509 }
4511 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4513 static int
4515 tree offset,
4517 {
4519 }
4521 /* Layout the empty base BINFO. EOC indicates the byte currently just
4522 past the end of the class, and should be correctly aligned for a
4523 class of the type indicated by BINFO; OFFSETS gives the offsets of
4524 the empty bases allocated so far. T is the most derived
4525 type. Return nonzero iff we added it at the end. */
4527 static bool
4529 splay_tree offsets)
4530 {
4531 tree alignment;
4535 tree type;
4537 {
4540 }
4541 else
4542 {
4545 }
4547 /* On some platforms (ARM), even empty classes will not be
4548 byte-aligned. */
4553 /* This routine should only be used for empty classes. */
4558 else
4561 /* This is an empty base class. We first try to put it at offset
4562 zero. */
4566 offset,
4567 offsets,
4569 {
4570 /* That didn't work. Now, we move forward from the next
4571 available spot in the class. */
4575 {
4577 offset,
4578 offsets,
4580 /* We finally found a spot where there's no overlap. */
4583 /* There's overlap here, too. Bump along to the next spot. */
4585 }
4586 }
4589 {
4594 }
4596 {
4601 }
4604 /* Adjust BINFO_OFFSET (binfo) to be exactly OFFSET. */
4607 else
4608 {
4612 }
4615 }
4617 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4618 fields at NEXT_FIELD, and return it. */
4620 static tree
4622 {
4623 /* Create the FIELD_DECL. */
4633 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4635 else
4636 {
4639 }
4650 /* Add the new FIELD_DECL to the list of fields for T. */
4656 }
4658 /* Layout the base given by BINFO in the class indicated by RLI.
4659 *BASE_ALIGN is a running maximum of the alignments of
4660 any base class. OFFSETS gives the location of empty base
4661 subobjects. T is the most derived type. Return nonzero if the new
4662 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4663 *NEXT_FIELD, unless BINFO is for an empty base class.
4665 Returns the location at which the next field should be inserted. */
4670 {
4675 /* This error is now reported in xref_tag, thus giving better
4676 location information. */
4679 /* Place the base class. */
4681 {
4682 tree decl;
4684 /* The containing class is non-empty because it has a non-empty
4685 base class. */
4688 /* Create the FIELD_DECL. */
4691 /* Try to place the field. It may take more than one try if we
4692 have a hard time placing the field without putting two
4693 objects of the same type at the same address. */
4695 }
4696 else
4697 {
4699 /* A nearly-empty class "has no proper base class that is empty,
4700 not morally virtual, and at an offset other than zero." */
4702 {
4705 /* The check above (used in G++ 3.2) is insufficient because
4706 an empty class placed at offset zero might itself have an
4707 empty base at a nonzero offset. */
4709 empty_base_at_nonzero_offset_p,
4710 size_zero_node,
4715 }
4717 /* We used to not create a FIELD_DECL for empty base classes because of
4718 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4719 be a problem anymore. We need them to handle initialization of C++17
4720 aggregate bases. */
4722 {
4728 }
4730 /* An empty virtual base causes a class to be non-empty
4731 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4732 here because that was already done when the virtual table
4733 pointer was created. */
4734 }
4736 /* Record the offsets of BINFO and its base subobjects. */
4740 }
4742 /* Layout all of the non-virtual base classes. Record empty
4743 subobjects in OFFSETS. T is the most derived type. Return nonzero
4744 if the type cannot be nearly empty. The fields created
4745 corresponding to the base classes will be inserted at
4746 *NEXT_FIELD. */
4748 static void
4751 {
4752 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4753 subobjects. */
4758 /* The primary base class is always allocated first. */
4761 {
4762 /* We need to walk BINFO_BASE_BINFO to find the access of the primary
4763 base, if it is direct. Indirect base fields are private. */
4766 {
4769 {
4772 }
4773 }
4775 primary_access,
4777 }
4779 /* Now allocate the rest of the bases. */
4781 {
4784 /* The primary base was already allocated above, so we don't
4785 need to allocate it again here. */
4789 /* Virtual bases are added at the end (a primary virtual base
4790 will have already been added). */
4797 }
4798 }
4800 /* Go through the TYPE_FIELDS of T issuing any appropriate
4801 diagnostics, figuring out which methods override which other
4802 methods, and so forth. */
4804 static void
4806 {
4809 {
4815 /* The name of the field is the original field name
4816 Save this in auxiliary field for later overloading. */
4818 {
4822 }
4828 "%<transaction_safe_dynamic%> may only be specified for "
4830 }
4832 /* Check whether the eligible special member functions (P0848) are
4833 user-provided. add_method arranged that the CLASSTYPE_MEMBER_VEC only
4834 has the eligible ones, unless none are eligible; TYPE_FIELDS also contains
4835 ineligible overloads, which is why this needs to be separate from the loop
4836 above. */
4839 {
4841 {
4842 /* P0848: At the end of the definition of a class, overload
4843 resolution is performed among the prospective destructors declared
4844 in that class with an empty argument list to select the destructor
4845 for the class, also known as the selected destructor. The program
4846 is ill-formed if overload resolution fails. */
4853 auto_diagnostic_group d;
4856 else
4860 /* Arbitrarily prune the overload set to a single function for
4861 sake of error recovery. */
4864 }
4867 }
4870 {
4881 }
4884 {
4895 }
4896 }
4898 /* FN is constructor, destructor or operator function. Clone the
4899 declaration to create a NAME'd variant. NEED_VTT_PARM_P and
4900 OMIT_INHERITED_PARMS_P are relevant if it's a cdtor. */
4902 static tree
4905 {
4906 /* Copy the function. */
4908 /* Reset the function name. */
4912 /* Clone constraints. */
4917 /* There's no pending inline data for this function. */
4922 {
4923 /* The base-class destructor is not virtual. */
4926 }
4928 {
4929 /* Set the operator code. */
4933 /* The operator could be virtual. */
4936 }
4941 /* If there was an in-charge parameter, drop it from the function
4942 type. */
4944 {
4947 /* Skip the `this' parameter. */
4949 /* Skip the in-charge parameter. */
4951 /* And the VTT parm, in a complete [cd]tor. */
4955 {
4956 /* If we're omitting inherited parms, that just leaves the VTT. */
4959 }
4963 parmtypes);
4969 }
4971 /* Copy the function parameters. */
4974 /* Remove the in-charge parameter. */
4976 {
4980 }
4982 /* And the VTT parm, in a complete [cd]tor. */
4984 {
4987 else
4988 {
4992 }
4993 }
4995 /* A base constructor inheriting from a virtual base doesn't get the
4996 arguments. */
5001 {
5004 }
5006 /* Create the RTL for this function. */
5009 /* Regardless of the current scope, this is a member function, so
5010 not at namespace scope. */
5014 }
5016 /* FN is an operator function, create a variant for CODE. */
5018 tree
5020 {
5023 }
5025 /* FN is a constructor or destructor. Clone the declaration to create
5026 a specialized in-charge or not-in-charge version, as indicated by
5027 NAME. */
5029 static tree
5032 {
5033 tree clone;
5035 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
5037 {
5049 }
5050 else
5051 {
5055 }
5057 /* Remember where this function came from. */
5060 /* Make it easy to find the CLONE given the FN. Note the
5061 template_result of a template will be chained this way too. */
5066 }
5068 /* Build the clones of FN, return the number of clones built. These
5069 will be inserted onto DECL_CHAIN of FN. */
5071 void
5074 {
5078 {
5079 /* For each constructor, we need two variants: an in-charge version
5080 and a not-in-charge version. */
5083 base_omits_inherited_p);
5085 }
5086 else
5087 {
5090 /* For each destructor, we need three variants: an in-charge
5091 version, a not-in-charge version, and an in-charge deleting
5092 version. We clone the deleting version first because that
5093 means it will go second on the TYPE_FIELDS list -- and that
5094 corresponds to the correct layout order in the virtual
5095 function table.
5097 For a non-virtual destructor, we do not build a deleting
5098 destructor. */
5100 {
5102 count++;
5103 }
5107 }
5109 /* The original is now an abstract function that is never
5110 emitted. */
5115 {
5118 }
5119 }
5121 /* Produce declarations for all appropriate clones of FN. If
5122 UPDATE_METHODS is true, the clones are added to the
5123 CLASSTYPE_MEMBER_VEC. */
5125 void
5127 {
5128 /* Avoid inappropriate cloning. */
5133 /* Base cdtors need a vtt parm if there are virtual bases. */
5136 /* Base ctor omits inherited parms it needs a vttparm and inherited
5137 from a virtual nase ctor. */
5142 }
5144 /* DECL is an in charge constructor, which is being defined. This will
5145 have had an in class declaration, from whence clones were
5146 declared. An out-of-class definition can specify additional default
5147 arguments. As it is the clones that are involved in overload
5148 resolution, we must propagate the information from the DECL to its
5149 clones. */
5151 void
5153 {
5154 tree clone;
5158 {
5163 /* Skip the 'this' parameter. */
5179 {
5181 {
5185 }
5191 {
5192 /* A default parameter has been added. Adjust the
5193 clone's parameters. */
5197 {
5200 clone_parms);
5202 }
5205 tree type
5208 clone_parms);
5216 }
5217 }
5219 }
5220 }
5222 /* For each of the constructors and destructors in T, create an
5223 in-charge and not-in-charge variant. */
5225 static void
5227 {
5228 /* We do not need to propagate the usingness to the clone, at this
5229 point that is not needed. */
5235 }
5237 /* Deduce noexcept for a destructor DTOR. */
5239 void
5241 {
5244 noexcept_deferred_spec);
5245 }
5247 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
5248 of TYPE for virtual functions which FNDECL overrides. Return a
5249 mask of the tm attributes found therein. */
5251 static int
5253 {
5255 tree base_binfo;
5259 {
5267 {
5271 else
5274 }
5275 else
5277 }
5280 }
5282 /* Subroutine of set_method_tm_attributes. Handle the checks and
5283 inheritance for one virtual method FNDECL. */
5285 static void
5287 {
5288 tree tm_attr;
5293 /* If FNDECL doesn't actually override anything (i.e. T is the
5294 class that first declares FNDECL virtual), then we're done. */
5301 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
5302 tm_pure must match exactly, otherwise no weakening of
5303 tm_safe > tm_callable > nothing. */
5304 /* ??? The tm_pure attribute didn't make the transition to the
5305 multivendor language spec. */
5307 {
5309 {
5312 }
5313 }
5314 /* If the overridden function is tm_pure, then FNDECL must be. */
5317 /* Look for base class combinations that cannot be satisfied. */
5319 {
5325 }
5326 /* If FNDECL did not declare an attribute, then inherit the most
5327 restrictive one. */
5329 {
5331 }
5332 /* Otherwise validate that we're not weaker than a function
5333 that is being overridden. */
5334 else
5335 {
5339 }
5342 err_override:
5346 }
5348 /* For each of the methods in T, propagate a class-level tm attribute. */
5350 static void
5352 {
5355 /* Don't bother collecting tm attributes if transactional memory
5356 support is not enabled. */
5360 /* Process virtual methods first, as they inherit directly from the
5361 base virtual function and also require validation of new attributes. */
5363 {
5364 tree vchain;
5367 {
5372 }
5373 }
5375 /* If the class doesn't have an attribute, nothing more to do. */
5380 /* Any method that does not yet have a tm attribute inherits
5381 the one from the class. */
5386 }
5388 /* Returns true if FN is a default constructor. */
5390 bool
5392 {
5395 }
5397 /* Returns true iff class T has a user-provided constructor that can be called
5398 with more than zero arguments. */
5400 bool
5402 {
5407 {
5413 }
5416 }
5418 /* Returns the defaulted constructor if T has one. Otherwise, returns
5419 NULL_TREE. */
5421 tree
5423 {
5428 {
5434 }
5437 }
5439 /* Returns true iff FN is a user-provided function, i.e. user-declared
5440 and not defaulted at its first declaration. */
5442 bool
5444 {
5449 }
5451 /* Returns true iff class T has a user-provided constructor. */
5453 bool
5455 {
5467 }
5469 /* Returns true iff class T has a user-provided or explicit constructor. */
5471 bool
5473 {
5481 {
5485 }
5488 }
5490 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5491 declared or explicitly defaulted in the class body) default
5492 constructor. */
5494 bool
5496 {
5503 {
5509 }
5512 }
5514 /* TYPE is being used as a virtual base, and has a non-trivial move
5515 assignment. Return true if this is due to there being a user-provided
5516 move assignment in TYPE or one of its subobjects; if there isn't, then
5517 multiple move assignment can't cause any harm. */
5519 bool
5521 {
5522 /* Does the type itself have a user-provided move assignment operator? */
5530 /* Do any of its bases? */
5532 tree base_binfo;
5537 /* Or non-static data members? */
5539 {
5544 }
5546 /* Seems not. */
5548 }
5550 /* If default-initialization leaves part of TYPE uninitialized, returns
5551 a DECL for the field or TYPE itself (DR 253). */
5553 tree
5555 {
5566 {
5570 }
5574 {
5578 }
5581 }
5583 /* Returns true iff for class T, a trivial synthesized default constructor
5584 would be constexpr. */
5586 bool
5588 {
5589 /* A defaulted trivial default constructor is constexpr
5590 if there is nothing to initialize. */
5592 /* A class with a vptr doesn't have a trivial default ctor.
5593 In C++20, a class can have transient uninitialized members, e.g.:
5595 struct S { int i; constexpr S() = default; };
5597 should work. */
5600 }
5602 /* Returns true iff class T has a constexpr default constructor. */
5604 bool
5606 {
5607 tree fns;
5610 {
5611 /* The caller should have stripped an enclosing array. */
5614 }
5616 {
5619 /* Non-trivial, we need to check subobject constructors. */
5621 }
5624 }
5626 /* Returns true iff class T has a constexpr default constructor or has an
5627 implicitly declared default constructor that we can't tell if it's constexpr
5628 without forcing a lazy declaration (which might cause undesired
5629 instantiations). */
5631 static bool
5633 {
5636 /* Assume it's constexpr. */
5639 }
5641 /* Returns true iff class T has a constexpr destructor. */
5643 bool
5645 {
5646 tree fns;
5649 /* Non-trivial, we need to check subobject destructors. */
5653 }
5655 /* Returns true iff class T has a constexpr destructor or has an
5656 implicitly declared destructor that we can't tell if it's constexpr
5657 without forcing a lazy declaration (which might cause undesired
5658 instantiations). */
5660 static bool
5662 {
5663 /* Until C++20, only trivial destruction is constexpr. */
5669 /* Assume it's constexpr. */
5673 }
5675 /* Returns true iff class TYPE has a virtual destructor. */
5677 bool
5679 {
5680 tree dtor;
5688 }
5690 /* Returns true iff T, a class, has a move-assignment or
5691 move-constructor. Does not lazily declare either.
5692 If USER_P is false, any move function will do. If it is true, the
5693 move function must be user-declared.
5695 Note that user-declared here is different from "user-provided",
5696 which doesn't include functions that are defaulted in the
5697 class. */
5699 bool
5701 {
5721 }
5723 /* True iff T has a move constructor that is not deleted. */
5725 bool
5727 {
5734 }
5736 /* If T, a class, has a user-provided copy constructor, copy assignment
5737 operator, or destructor, returns that function. Otherwise, null. */
5739 tree
5741 {
5744 {
5748 }
5754 {
5759 }
5762 {
5766 }
5769 }
5771 /* True iff T has a member or friend declaration of operator OP. */
5773 bool
5775 {
5783 }
5786 /* If T has a defaulted member or friend declaration of OP, return it. */
5788 tree
5790 {
5793 {
5797 }
5801 {
5805 }
5807 }
5809 /* Nonzero if we need to build up a constructor call when initializing an
5810 object of this class, either because it has a user-declared constructor
5811 or because it doesn't have a default constructor (so we need to give an
5812 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5813 what you care about is whether or not an object can be produced by a
5814 constructor (e.g. so we don't set TREE_READONLY on const variables of
5815 such type); use this function when what you care about is whether or not
5816 to try to call a constructor to create an object. The latter case is
5817 the former plus some cases of constructors that cannot be called. */
5819 bool
5821 {
5822 tree inner;
5832 /* A user-declared constructor might be private, and a constructor might
5833 be trivial but deleted. */
5836 {
5843 }
5845 }
5847 /* Like type_build_ctor_call, but for destructors. */
5849 bool
5851 {
5852 tree inner;
5861 /* A user-declared destructor might be private, and a destructor might
5862 be trivial but deleted. */
5865 {
5872 }
5874 }
5876 /* Returns TRUE iff we need a cookie when dynamically allocating an
5877 array whose elements have the indicated class TYPE. */
5879 static bool
5881 {
5882 tree fns;
5887 /* If there's a non-trivial destructor, we need a cookie. In order
5888 to iterate through the array calling the destructor for each
5889 element, we'll have to know how many elements there are. */
5893 /* If the usual deallocation function is a two-argument whose second
5894 argument is of type `size_t', then we have to pass the size of
5895 the array to the deallocation function, so we will need to store
5896 a cookie. */
5900 /* If there are no `operator []' members, or the lookup is
5901 ambiguous, then we don't need a cookie. */
5904 /* Loop through all of the functions. */
5906 {
5909 /* See if this function is a one-argument delete function. If
5910 it is, then it will be the usual deallocation function. */
5914 /* Do not consider this function if its second argument is an
5915 ellipsis. */
5918 /* Otherwise, if we have a two-argument function and the second
5919 argument is `size_t', it will be the usual deallocation
5920 function -- unless there is one-argument function, too. */
5924 }
5927 }
5929 /* Finish computing the `literal type' property of class type T.
5931 At this point, we have already processed base classes and
5932 non-static data members. We need to check whether the copy
5933 constructor is trivial, the destructor is trivial, and there
5934 is a trivial default constructor or at least one constexpr
5935 constructor other than the copy constructor. */
5937 static void
5939 {
5940 tree fn;
5954 /* C++14 DR 1684 removed this restriction. */
5962 {
5965 {
5966 auto_diagnostic_group d;
5968 "enclosing class of %<constexpr%> non-static "
5971 }
5972 }
5973 }
5975 /* T is a non-literal type used in a context which requires a constant
5976 expression. Explain why it isn't literal. */
5978 void
5980 {
5990 /* Already explained. */
5993 auto_diagnostic_group d;
5997 " %qT is a closure type, which is only literal in "
6004 t);
6009 {
6011 " %q+T is not an aggregate, does not have a trivial "
6012 "default constructor, and has no %<constexpr%> constructor that "
6015 /* Note that we can't simply call locate_ctor because when the
6016 constructor is deleted it just returns NULL_TREE. */
6018 {
6025 {
6028 else
6031 }
6032 }
6033 }
6034 else
6035 {
6039 {
6042 {
6048 }
6049 }
6051 {
6052 tree ftype;
6057 {
6060 field);
6063 }
6067 }
6068 }
6069 }
6071 /* Check the validity of the bases and members declared in T. Add any
6072 implicitly-generated functions (like copy-constructors and
6073 assignment operators). Compute various flag bits (like
6074 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
6075 level: i.e., independently of the ABI in use. */
6077 static void
6079 {
6080 /* Nonzero if the implicitly generated copy constructor should take
6081 a non-const reference argument. */
6083 /* Nonzero if the implicitly generated assignment operator
6084 should take a non-const reference argument. */
6086 tree access_decls;
6089 tree fn;
6091 /* By default, we use const reference arguments and generate default
6092 constructors. */
6096 /* Check all the base-classes and set FMEM members to point to arrays
6097 of potential interest. */
6100 /* Deduce noexcept on destructor. This needs to happen after we've set
6101 triviality flags appropriately for our bases, and before checking
6102 overriden virtual functions via check_methods. */
6108 /* Check all the method declarations. */
6111 /* Save the initial values of these flags which only indicate whether
6112 or not the class has user-provided functions. As we analyze the
6113 bases and members we can set these flags for other reasons. */
6117 /* Check all the data member declarations. We cannot call
6118 check_field_decls until we have called check_bases check_methods,
6119 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
6120 being set appropriately. */
6125 /* A nearly-empty class has to be vptr-containing; a nearly empty
6126 class contains just a vptr. */
6130 /* Do some bookkeeping that will guide the generation of implicitly
6131 declared member functions. */
6134 /* We need to call a constructor for this class if it has a
6135 user-provided constructor, or if the default constructor is going
6136 to initialize the vptr. (This is not an if-and-only-if;
6137 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
6138 themselves need constructing.) */
6141 /* [dcl.init.aggr]
6143 An aggregate is an array or a class with no user-provided
6144 constructors ... and no virtual functions.
6146 Again, other conditions for being an aggregate are checked
6147 elsewhere. */
6153 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
6154 retain the old definition internally for ABI reasons. */
6163 /* Is this class non-layout-POD because it wasn't an aggregate in C++98? */
6165 {
6167 /* It's non-POD for another reason. */
6171 }
6173 /* If the only explicitly declared default constructor is user-provided,
6174 set TYPE_HAS_COMPLEX_DFLT. */
6180 /* Warn if a public base of a polymorphic type has an accessible
6181 non-virtual destructor. It is only now that we know the class is
6182 polymorphic. Although a polymorphic base will have a already
6183 been diagnosed during its definition, we warn on use too. */
6185 {
6188 tree base_binfo;
6192 {
6200 basetype);
6201 }
6202 }
6204 /* If the class has no user-declared constructor, but does have
6205 non-static const or reference data members that can never be
6206 initialized, issue a warning. */
6208 /* Classes with user-declared constructors are presumed to
6209 initialize these members. */
6211 /* Aggregates can be initialized with brace-enclosed
6212 initializers. */
6214 {
6215 tree field;
6218 {
6219 tree type;
6236 }
6237 }
6239 /* Synthesize any needed methods. */
6241 cant_have_const_ctor,
6242 no_const_asn_ref);
6244 /* Check defaulted declarations here so we have cant_have_const_ctor
6245 and don't need to worry about clones. */
6250 {
6251 /* ...except handle comparisons later, in finish_struct_1. */
6257 {
6258 bool imp_const_p
6264 /* If the function is defaulted outside the class, we just
6265 give the synthesis error. Core Issue #1331 says this is
6266 no longer ill-formed, it is defined as deleted instead. */
6268 }
6270 }
6273 /* "This class type is not an aggregate." */
6276 /* Compute the 'literal type' property before we
6277 do anything with non-static member functions. */
6280 /* Create the in-charge and not-in-charge variants of constructors
6281 and destructors. */
6284 /* Process the using-declarations. */
6288 /* Figure out whether or not we will need a cookie when dynamically
6289 allocating an array of this type. */
6292 }
6294 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
6295 accordingly. If a new vfield was created (because T doesn't have a
6296 primary base class), then the newly created field is returned. It
6297 is not added to the TYPE_FIELDS list; it is the caller's
6298 responsibility to do that. Accumulate declared virtual functions
6299 on VIRTUALS_P. */
6301 static tree
6303 {
6304 tree fn;
6306 /* Collect the virtual functions declared in T. */
6311 {
6320 }
6322 /* If we couldn't find an appropriate base class, create a new field
6323 here. Even if there weren't any new virtual functions, we might need a
6324 new virtual function table if we're supposed to include vptrs in
6325 all classes that need them. */
6327 {
6328 /* We build this decl with vtbl_ptr_type_node, which is a
6329 `vtable_entry_type*'. It might seem more precise to use
6330 `vtable_entry_type (*)[N]' where N is the number of virtual
6331 functions. However, that would require the vtable pointer in
6332 base classes to have a different type than the vtable pointer
6333 in derived classes. We could make that happen, but that
6334 still wouldn't solve all the problems. In particular, the
6335 type-based alias analysis code would decide that assignments
6336 to the base class vtable pointer can't alias assignments to
6337 the derived class vtable pointer, since they have different
6338 types. Thus, in a derived class destructor, where the base
6339 class constructor was inlined, we could generate bad code for
6340 setting up the vtable pointer.
6342 Therefore, we use one type for all vtable pointers. We still
6343 use a type-correct type; it's just doesn't indicate the array
6344 bounds. That's better than using `void*' or some such; it's
6345 cleaner, and it let's the alias analysis code know that these
6346 stores cannot alias stores to void*! */
6347 tree field;
6360 /* This class is non-empty. */
6364 }
6367 }
6369 /* Add OFFSET to all base types of BINFO which is a base in the
6370 hierarchy dominated by T.
6372 OFFSET, which is a type offset, is number of bytes. */
6374 static void
6376 {
6378 tree primary_binfo;
6379 tree base_binfo;
6381 /* Update BINFO's offset. */
6386 offset));
6388 /* Find the primary base class. */
6394 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
6395 downwards. */
6397 {
6398 /* Don't do the primary base twice. */
6406 }
6407 }
6409 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
6410 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
6411 empty subobjects of T. */
6413 static void
6415 {
6416 tree vbase;
6423 /* Find the last field. The artificial fields created for virtual
6424 bases will go after the last extant field to date. */
6429 /* Go through the virtual bases, allocating space for each virtual
6430 base that is not already a primary base class. These are
6431 allocated in inheritance graph order. */
6433 {
6438 {
6439 /* This virtual base is not a primary base of any class in the
6440 hierarchy, so we have to add space for it. */
6442 access_private_node,
6444 }
6445 }
6446 }
6448 /* Returns the offset of the byte just past the end of the base class
6449 BINFO. */
6451 static tree
6453 {
6454 tree size;
6459 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
6460 allocate some space for it. It cannot have virtual bases, so
6461 TYPE_SIZE_UNIT is fine. */
6463 else
6467 }
6469 /* Returns one of three variations of the ending offset of T. If MODE is
6470 eoc_nvsize, the result is the ABI "nvsize" (i.e. sizeof before allocating
6471 vbases). If MODE is eoc_vsize, the result is the sizeof after allocating
6472 vbases but before rounding, which is not named in the ABI. If MODE is
6473 eoc_nv_or_dsize, the result is the greater of "nvsize" and "dsize" (the size
6474 of the actual data in the class, kinda), as used for allocation of
6475 potentially-overlapping fields. */
6478 static tree
6480 {
6483 tree binfo;
6484 tree base_binfo;
6485 tree offset;
6490 {
6499 }
6504 {
6507 /* DECL_SIZE_UNIT can be null for a flexible array. */
6511 /* For empty fields DECL_SIZE_UNIT is 0, but we want the
6512 size of the type (usually 1) for computing nvsize. */
6516 {
6521 }
6522 else
6526 }
6531 {
6533 /* For dsize, don't count trailing empty bases. */
6536 else
6540 }
6543 }
6545 /* Warn as appropriate about the change in whether we pack into the tail
6546 padding of FIELD, a base field which has a C++14 aggregate type with default
6547 member initializers. */
6549 static void
6551 {
6571 {
6575 "%<-std=c++14%> and up changes in "
6577 else
6579 "%<-std=c++14%> and up changes in "
6581 }
6582 }
6584 /* Warn about bases of T that are inaccessible because they are
6585 ambiguous. For example:
6587 struct S {};
6588 struct T : public S {};
6589 struct U : public S, public T {};
6591 Here, `(S*) new U' is not allowed because there are two `S'
6592 subobjects of U. */
6594 static void
6596 {
6599 tree basetype;
6600 tree binfo;
6601 tree base_binfo;
6603 /* If not checking for warning then return early. */
6607 /* If there are no repeated bases, nothing can be ambiguous. */
6611 /* Check direct bases. */
6614 {
6620 }
6622 /* Check for ambiguous virtual bases. */
6626 {
6632 }
6633 }
6635 /* Compare two INTEGER_CSTs K1 and K2. */
6637 static int
6639 {
6641 }
6643 /* Increase the size indicated in RLI to account for empty classes
6644 that are "off the end" of the class. */
6646 static void
6648 {
6649 tree eoc;
6650 tree rli_size;
6652 /* It might be the case that we grew the class to allocate a
6653 zero-sized base class. That won't be reflected in RLI, yet,
6654 because we are willing to overlay multiple bases at the same
6655 offset. However, now we need to make sure that RLI is big enough
6656 to reflect the entire class. */
6661 {
6662 /* The size should have been rounded to a whole byte. */
6665 rli->bitpos
6674 }
6675 }
6677 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
6678 BINFO_OFFSETs for all of the base-classes. Position the vtable
6679 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
6681 static void
6683 {
6684 tree non_static_data_members;
6685 tree field;
6686 tree vptr;
6687 record_layout_info rli;
6688 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6689 types that appear at that offset. */
6690 splay_tree empty_base_offsets;
6691 /* True if the last field laid out was a bit-field. */
6693 /* The location at which the next field should be inserted. */
6696 /* Keep track of the first non-static data member. */
6699 /* Start laying out the record. */
6702 /* Mark all the primary bases in the hierarchy. */
6705 /* Create a pointer to our virtual function table. */
6708 /* The vptr is always the first thing in the class. */
6710 {
6715 }
6716 else
6719 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6724 /* Layout the non-static data members. */
6726 {
6727 tree type;
6728 tree padding;
6730 /* We still pass things that aren't non-static data members to
6731 the back end, in case it wants to do something with them. */
6733 {
6735 /* If the static data member has incomplete type, keep track
6736 of it so that it can be completed later. (The handling
6737 of pending statics in finish_record_layout is
6738 insufficient; consider:
6740 struct S1;
6741 struct S2 { static S1 s1; };
6743 At this point, finish_record_layout will be called, but
6744 S1 is still incomplete.) */
6746 {
6748 /* The visibility of static data members is determined
6749 at their point of declaration, not their point of
6750 definition. */
6752 }
6754 }
6766 {
6767 /* if D is a potentially-overlapping data member, update sizeof(C) to
6768 max (sizeof(C), offset(D)+max (nvsize(D), dsize(D))). */
6771 else
6772 {
6776 }
6777 }
6779 /* If this field is a bit-field whose width is greater than its
6780 type, then there are some special rules for allocating
6781 it. */
6784 {
6786 /* We must allocate the bits as if suitably aligned for the
6787 longest integer type that fits in this many bits. Then,
6788 we are supposed to use the left over bits as additional
6789 padding. */
6791 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6799 {
6801 /* Too big, so our current guess is what we want. */
6803 /* Not bigger than limit, ok */
6805 }
6807 /* Figure out how much additional padding is required. */
6809 /* In a union, the padding field must have the full width
6810 of the bit-field; all fields start at offset zero. */
6812 else
6819 /* An unnamed bitfield does not normally affect the
6820 alignment of the containing class on a target where
6821 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6822 make any exceptions for unnamed bitfields when the
6823 bitfields are longer than their types. Therefore, we
6824 temporarily give the field a name. */
6826 {
6829 }
6835 empty_base_offsets);
6838 /* Now that layout has been performed, set the size of the
6839 field to the size of its declared type; the rest of the
6840 field is effectively invisible. */
6842 /* We must also reset the DECL_MODE of the field. */
6844 }
6846 {
6849 }
6850 else
6852 empty_base_offsets);
6854 /* Remember the location of any empty classes in FIELD. */
6857 /* If a bit-field does not immediately follow another bit-field,
6858 and yet it starts in the middle of a byte, we have failed to
6859 comply with the ABI. */
6862 /* The TREE_NO_WARNING flag gets set by Objective-C when
6863 laying out an Objective-C class. The ObjC ABI differs
6864 from the C++ ABI, and so we do not want a warning
6865 here. */
6867 && !last_field_was_bitfield
6870 bitsize_unit_node)))
6872 "offset of %qD is not ABI-compliant and may "
6875 /* The middle end uses the type of expressions to determine the
6876 possible range of expression values. In order to optimize
6877 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6878 must be made aware of the width of "i", via its type.
6880 Because C++ does not have integer types of arbitrary width,
6881 we must (for the purposes of the front end) convert from the
6882 type assigned here to the declared type of the bitfield
6883 whenever a bitfield expression is used as an rvalue.
6884 Similarly, when assigning a value to a bitfield, the value
6885 must be converted to the type given the bitfield here. */
6887 {
6892 {
6899 }
6900 }
6902 /* If we needed additional padding after this field, add it
6903 now. */
6905 {
6906 tree padding_field;
6909 FIELD_DECL,
6910 NULL_TREE,
6911 char_type_node);
6919 NULL_TREE,
6920 empty_base_offsets);
6921 }
6924 }
6927 {
6928 /* Make sure that we are on a byte boundary so that the size of
6929 the class without virtual bases will always be a round number
6930 of bytes. */
6933 }
6935 /* We used to remove zero width bitfields at this point since PR42217,
6936 while the C FE never did that. That caused ABI differences on various
6937 targets. Set the DECL_FIELD_CXX_ZERO_WIDTH_BIT_FIELD flag on them
6938 instead, so that the backends can emit -Wpsabi warnings in the cases
6939 where the ABI changed. */
6941 {
6944 /* We should not be confused by the fact that grokbitfield
6945 temporarily sets the width of the bit field into
6946 DECL_BIT_FIELD_REPRESENTATIVE (field).
6947 check_bitfield_decl eventually sets DECL_SIZE (field)
6948 to that width. */
6953 }
6956 {
6957 /* T needs a different layout as a base (eliding virtual bases
6958 or whatever). Create that version. */
6967 /* If the ABI version is not at least two, and the last
6968 field was a bit-field, RLI may not be on a byte
6969 boundary. In particular, rli_size_unit_so_far might
6970 indicate the last complete byte, while rli_size_so_far
6971 indicates the total number of bits used. Therefore,
6972 rli_size_so_far, rather than rli_size_unit_so_far, is
6973 used to compute TYPE_SIZE_UNIT. */
6975 /* Set the size and alignment for the new type. */
6983 eoc);
6995 /* Copy the non-static data members of T. This will include its
6996 direct non-virtual bases & vtable. */
7000 {
7002 /* Zap any NSDMI, it's not needed and might be a deferred
7003 parse. */
7007 }
7010 /* We use the base type for trivial assignments, and hence it
7011 needs a mode. */
7014 /* Record the base version of the type. */
7016 }
7017 else
7020 /* Every empty class contains an empty class. */
7024 /* Set the TYPE_DECL for this type to contain the right
7025 value for DECL_OFFSET, so that we can use it as part
7026 of a COMPONENT_REF for multiple inheritance. */
7029 /* Now fix up any virtual base class types that we left lying
7030 around. We must get these done before we try to lay out the
7031 virtual function table. As a side-effect, this will remove the
7032 base subobject fields. */
7035 /* Make sure that empty classes are reflected in RLI at this
7036 point. */
7039 /* Make sure not to create any structures with zero size. */
7045 /* If this is a non-POD, declaring it packed makes a difference to how it
7046 can be used as a field; don't let finalize_record_size undo it. */
7050 /* Let the back end lay out the type. */
7053 /* If we didn't end up needing an as-base type, don't use it. */
7055 /* If T's CLASSTYPE_AS_BASE is TYPE_USER_ALIGN, but T is not,
7056 replacing the as-base type would change CLASSTYPE_USER_ALIGN,
7057 causing us to lose the user-specified alignment as in PR94050. */
7069 /* Warn about bases that can't be talked about due to ambiguity. */
7072 /* Now that we're done with layout, give the base fields the real types. */
7077 /* Clean up. */
7084 }
7086 /* Determine the "key method" for the class type indicated by TYPE,
7087 and set CLASSTYPE_KEY_METHOD accordingly. */
7089 void
7091 {
7092 tree method;
7099 /* The key method is the first non-pure virtual function that is not
7100 inline at the point of class definition. On some targets the
7101 key function may not be inline; those targets should not call
7102 this function until the end of the translation unit. */
7108 {
7111 }
7114 }
7116 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
7117 class data member of non-zero size, otherwise false. */
7121 {
7129 {
7133 }
7136 }
7138 /* Used by find_flexarrays and related functions. */
7140 struct flexmems_t
7141 {
7142 /* The first flexible array member or non-zero array member found
7143 in the order of layout. */
7144 tree array;
7145 /* First non-static non-empty data member in the class or its bases. */
7146 tree first;
7147 /* The first non-static non-empty data member following either
7148 the flexible array member, if found, or the zero-length array member
7149 otherwise. AFTER[1] refers to the first such data member of a union
7150 of which the struct containing the flexible array member or zero-length
7151 array is a member, or NULL when no such union exists. This element is
7152 only used during searching, not for diagnosing problems. AFTER[0]
7153 refers to the first such data member that is not a member of such
7154 a union. */
7157 /* Refers to a struct (not union) in which the struct of which the flexible
7158 array is member is defined. Used to diagnose strictly (according to C)
7159 invalid uses of the latter structs. */
7160 tree enclosing;
7161 };
7163 /* Find either the first flexible array member or the first zero-length
7164 array, in that order of preference, among members of class T (but not
7165 its base classes), and set members of FMEM accordingly.
7166 BASE_P is true if T is a base class of another class.
7167 PUN is set to the outermost union in which the flexible array member
7168 (or zero-length array) is defined if one such union exists, otherwise
7169 to NULL.
7170 Similarly, PSTR is set to a data member of the outermost struct of
7171 which the flexible array is a member if one such struct exists,
7172 otherwise to NULL. */
7174 static void
7178 {
7179 /* Set the "pointer" to the outermost enclosing union if not set
7180 yet and maintain it for the remainder of the recursion. */
7185 {
7189 /* Is FLD a typedef for an anonymous struct? */
7191 /* FIXME: Note that typedefs (as well as arrays) need to be fully
7192 handled elsewhere so that errors like the following are detected
7193 as well:
7194 typedef struct { int i, a[], j; } S; // bug c++/72753
7195 S s [2]; // bug c++/68489
7196 */
7201 {
7202 /* Check the nested unnamed type referenced via a typedef
7203 independently of FMEM (since it's not a data member of
7204 the enclosing class). */
7207 }
7209 /* Skip anything that's GCC-generated or not a (non-static) data
7210 member. */
7214 /* Type of the member. */
7219 /* Determine the type of the array element or object referenced
7220 by the member so that it can be checked for flexible array
7221 members if it hasn't been yet. */
7228 {
7230 {
7231 /* Once the member after the flexible array has been found
7232 we're done. */
7235 }
7238 {
7239 /* Descend into the non-static member struct or union and try
7240 to find a flexible array member or zero-length array among
7241 its members. This is only necessary for anonymous types
7242 and types in whose context the current type T has not been
7243 defined (the latter must not be checked again because they
7244 are already in the process of being checked by one of the
7245 recursive calls). */
7250 /* If this member isn't anonymous and a prior non-flexible array
7251 member has been seen in one of the enclosing structs, clear
7252 the FIRST member since it doesn't contribute to the flexible
7253 array struct's members. */
7264 {
7265 /* Restore the FIRST member reset above if no flexible
7266 array member has been found in this member's struct. */
7268 }
7270 /* If the member struct contains the first flexible array
7271 member, or if this member is a base class, continue to
7272 the next member and avoid setting the FMEM->NEXT pointer
7273 to point to it. */
7276 }
7277 }
7280 {
7281 /* Remember the first non-static data member. */
7285 /* Remember the first non-static data member after the flexible
7286 array member, if one has been found, or the zero-length array
7287 if it has been found. */
7290 }
7292 /* Skip non-arrays. */
7296 /* Determine the upper bound of the array if it has one. */
7298 {
7300 {
7301 /* Make a record of the zero-length array if either one
7302 such field or a flexible array member has been seen to
7303 handle the pathological and unlikely case of multiple
7304 such members. */
7307 }
7309 {
7310 /* Remember the first zero-length array unless a flexible array
7311 member has already been seen. */
7314 }
7315 }
7316 else
7317 {
7318 /* Flexible array members have no upper bound. */
7320 {
7322 {
7323 /* Replace the zero-length array if it's been stored and
7324 reset the after pointer. */
7328 }
7330 /* Make a record of another flexible array member. */
7332 }
7333 else
7334 {
7337 }
7338 }
7339 }
7340 }
7342 /* Diagnose a strictly (by the C standard) invalid use of a struct with
7343 a flexible array member (or the zero-length array extension). */
7345 static void
7347 {
7349 {
7350 auto_diagnostic_group d;
7361 }
7362 }
7364 /* Issue diagnostics for invalid flexible array members or zero-length
7365 arrays that are not the last elements of the containing class or its
7366 base classes or that are its sole members. */
7368 static void
7370 {
7375 {
7378 }
7380 /* Has a diagnostic been issued? */
7386 {
7393 {
7396 auto_diagnostic_group d;
7398 {
7401 }
7402 }
7403 }
7404 else
7405 {
7412 {
7416 auto_diagnostic_group d;
7419 /* In the unlikely event that the member following the flexible
7420 array member is declared in a different class, or the member
7421 overlaps another member of a common union, point to it.
7422 Otherwise it should be obvious. */
7426 {
7431 }
7432 }
7433 }
7437 }
7440 /* Recursively check to make sure that any flexible array or zero-length
7441 array members of class T or its bases are valid (i.e., not the sole
7442 non-static data member of T and, if one exists, that it is the last
7443 non-static data member of T and its base classes. FMEM is expected
7444 to be initially null and is used internally by recursive calls to
7445 the function. Issue the appropriate diagnostics for the array member
7446 that fails the checks. */
7448 static void
7451 {
7452 /* Initialize the result of a search for flexible array and zero-length
7453 array members. Avoid doing any work if the most interesting FMEM data
7454 have already been populated. */
7463 /* Recursively check the primary base class first. */
7465 {
7468 }
7470 /* Recursively check the base classes. */
7473 {
7476 /* The primary base class was already checked above. */
7480 /* Virtual base classes are at the end. */
7484 /* Check the base class. */
7486 }
7489 {
7490 /* Check virtual base classes only once per derived class.
7491 I.e., this check is not performed recursively for base
7492 classes. */
7494 tree base_binfo;
7498 {
7499 /* Check the virtual base class. */
7503 }
7504 }
7506 /* Is the type unnamed (and therefore a member of it potentially
7507 an anonymous struct or union)? */
7512 /* Search the members of the current (possibly derived) class, skipping
7513 unnamed structs and unions since those could be anonymous. */
7518 {
7519 /* Issue diagnostics for invalid flexible and zero-length array
7520 members found in base classes or among the members of the current
7521 class. Ignore anonymous structs and unions whose members are
7522 considered to be members of the enclosing class and thus will
7523 be diagnosed when checking it. */
7525 }
7526 }
7528 /* Perform processing required when the definition of T (a class type)
7529 is complete. Diagnose invalid definitions of flexible array members
7530 and zero-size arrays. */
7532 void
7534 {
7535 tree x;
7536 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
7540 {
7545 }
7547 /* If this type was previously laid out as a forward reference,
7548 make sure we lay it out again. */
7552 /* Make assumptions about the class; we'll reset the flags if
7553 necessary. */
7559 /* Do end-of-class semantic processing: checking the validity of the
7560 bases and members and add implicitly generated methods. */
7563 /* Find the key method. */
7565 {
7566 /* The Itanium C++ ABI permits the key method to be chosen when
7567 the class is defined -- even though the key method so
7568 selected may later turn out to be an inline function. On
7569 some systems (such as ARM Symbian OS) the key method cannot
7570 be determined until the end of the translation unit. On such
7571 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
7572 will cause the class to be added to KEYED_CLASSES. Then, in
7573 finish_file we will determine the key method. */
7577 /* If a polymorphic class has no key method, we may emit the vtable
7578 in every translation unit where the class definition appears. If
7579 we're devirtualizing, we can look into the vtable even if we
7580 aren't emitting it. */
7583 }
7585 /* Layout the class itself. */
7587 /* COMPLETE_TYPE_P is now true. */
7591 /* With the layout complete, check for flexible array members and
7592 zero-length arrays that might overlap other members in the final
7593 layout. */
7598 /* If necessary, create the primary vtable for this class. */
7600 {
7601 /* We must enter these virtuals into the table. */
7605 /* Here we know enough to change the type of our virtual
7606 function table, but we will wait until later this function. */
7609 /* If we're warning about ABI tags, check the types of the new
7610 virtual functions. */
7614 }
7617 {
7619 tree fn;
7626 /* Add entries for virtual functions introduced by this class. */
7630 /* Set DECL_VINDEX for all functions declared in this class. */
7632 fn;
7634 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
7636 {
7640 /* A thunk. We should never be calling this entry directly
7641 from this vtable -- we'd use the entry for the non
7642 thunk base function. */
7646 }
7647 }
7655 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
7656 for any static member objects of the type we're working on. */
7659 {
7660 /* Synthesize constexpr defaulted comparisons. */
7666 }
7672 /* Complain if one of the field types requires lower visibility. */
7675 /* Make the rtl for any new vtables we have created, and unmark
7676 the base types we marked. */
7679 /* Build the VTT for T. */
7686 "%q#T has virtual functions and accessible"
7694 /* Class layout, assignment of virtual table slots, etc., is now
7695 complete. Give the back end a chance to tweak the visibility of
7696 the class or perform any other required target modifications. */
7706 /* Finish debugging output for this type. */
7710 {
7713 {
7716 }
7718 {
7721 else
7722 {
7725 }
7727 }
7729 {
7731 "the type of the first field has a different ABI from the "
7734 }
7735 }
7736 }
7738 /* When T was built up, the member declarations were added in reverse
7739 order. Rearrange them to declaration order. */
7741 void
7743 {
7744 tree next;
7745 tree prev;
7746 tree x;
7748 /* The following lists are all in reverse order. Put them in
7749 declaration order now. */
7752 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
7753 order, so we can't just use nreverse. Due to stat_hack
7754 chicanery in finish_member_declaration. */
7759 {
7763 }
7766 {
7769 }
7770 }
7772 tree
7774 {
7777 /* Now that we've got all the field declarations, reverse everything
7778 as necessary. */
7784 /* Nadger the current location so that diagnostics point to the start of
7785 the struct, not the end. */
7789 {
7790 tree x;
7794 {
7798 }
7800 {
7803 }
7805 /* Also add a USING_DECL for operator=. We know there'll be (at
7806 least) one, but we don't know the signature(s). We want name
7807 lookup not to fail or recurse into bases. This isn't added
7808 to the template decl list so we drop this at instantiation
7809 time. */
7811 NULL_TREE);
7821 /* COMPLETE_TYPE_P is now true. */
7825 /* We need to emit an error message if this type was used as a parameter
7826 and it is an abstract type, even if it is a template. We construct
7827 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7828 account and we call complete_vars with this type, which will check
7829 the PARM_DECLS. Note that while the type is being defined,
7830 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7831 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7838 /* Remember current #pragma pack value. */
7842 {
7846 }
7850 /* Fix up any variants we've already built. */
7852 }
7853 else
7855 /* COMPLETE_TYPE_P is now true. */
7860 {
7861 /* People keep complaining that the compiler crashes on an invalid
7862 definition of initializer_list, so I guess we should explicitly
7863 reject it. What the compiler internals care about is that it's a
7864 template and has a pointer field followed by size_type field. */
7867 {
7870 {
7874 }
7875 }
7876 /* It also cannot be a union. */
7881 }
7889 else
7901 /* Lambdas are defined by the LAMBDA_EXPR. */
7906 }
7907 \f
7908 /* Hash table to avoid endless recursion when handling references. */
7911 /* Return the dynamic type of INSTANCE, if known.
7912 Used to determine whether the virtual function table is needed
7913 or not.
7915 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7916 of our knowledge of its type. *NONNULL should be initialized
7917 before this function is called. */
7919 static tree
7921 {
7922 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7925 {
7929 else
7933 /* This is a call to a constructor, hence it's never zero. */
7936 {
7940 }
7944 /* This is a call to a constructor, hence it's never zero. */
7946 {
7950 }
7959 /* Propagate nonnull. */
7964 CASE_CONVERT:
7970 {
7971 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7972 with a real object -- given &p->f, p can still be null. */
7974 /* ??? Probably should check DECL_WEAK here. */
7977 }
7981 /* If this component is really a base class reference, then the field
7982 itself isn't definitive. */
7991 {
7995 }
7996 /* fall through. */
8001 {
8005 }
8007 {
8011 /* if we're in a ctor or dtor, we know our type. If
8012 current_class_ptr is set but we aren't in a function, we're in
8013 an NSDMI (and therefore a constructor). */
8018 {
8022 }
8023 }
8025 {
8026 /* We only need one hash table because it is always left empty. */
8028 fixed_type_or_null_ref_ht
8031 /* Reference variables should be references to objects. */
8035 /* Enter the INSTANCE in a table to prevent recursion; a
8036 variable's initializer may refer to the variable
8037 itself. */
8042 {
8043 tree type;
8052 }
8053 }
8059 else
8060 /* TODO: Recursion may be correct for some non-location-wrapper
8061 uses of VIEW_CONVERT_EXPR. */
8066 }
8067 #undef RECUR
8068 }
8070 /* Return nonzero if the dynamic type of INSTANCE is known, and
8071 equivalent to the static type. We also handle the case where
8072 INSTANCE is really a pointer. Return negative if this is a
8073 ctor/dtor. There the dynamic type is known, but this might not be
8074 the most derived base of the original object, and hence virtual
8075 bases may not be laid out according to this type.
8077 Used to determine whether the virtual function table is needed
8078 or not.
8080 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
8081 of our knowledge of its type. *NONNULL should be initialized
8082 before this function is called. */
8084 int
8086 {
8089 tree fixed;
8091 /* processing_template_decl can be false in a template if we're in
8092 instantiate_non_dependent_expr, but we still want to suppress
8093 this check. */
8095 {
8096 /* In a template we only care about the type of the result. */
8100 }
8112 }
8114 \f
8115 void
8117 {
8120 current_class_stack
8127 }
8129 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
8131 static void
8133 {
8134 tree type;
8136 /* We are re-entering the same class we just left, so we don't
8137 have to search the whole inheritance matrix to find all the
8138 decls to bind again. Instead, we install the cached
8139 class_shadowed list and walk through it binding names. */
8142 /* Restore IDENTIFIER_TYPE_VALUE. */
8144 type;
8147 }
8149 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
8150 appropriate for TYPE.
8152 So that we may avoid calls to lookup_name, we cache the _TYPE
8153 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
8155 For multiple inheritance, we perform a two-pass depth-first search
8156 of the type lattice. */
8158 void
8160 {
8161 class_stack_node_t csn;
8165 /* Make sure there is enough room for the new entry on the stack. */
8167 {
8169 current_class_stack
8171 current_class_stack_size);
8172 }
8174 /* Insert a new entry on the class stack. */
8181 current_class_depth++;
8183 /* Now set up the new type. */
8189 /* By default, things in classes are private, while things in
8190 structures or unions are public. */
8192 ? access_private_node
8198 {
8199 /* Forcibly remove any old class remnants. */
8201 }
8207 else
8209 }
8211 /* Get out of the current class scope. If we were in a class scope
8212 previously, that is the one popped to. */
8214 void
8216 {
8219 current_class_depth--;
8225 }
8227 /* Mark the top of the class stack as hidden. */
8229 void
8231 {
8234 }
8236 /* Mark the top of the class stack as un-hidden. */
8238 void
8240 {
8243 }
8245 /* If the class type currently being defined is either T or
8246 a nested type of T, returns the type from the current_class_stack,
8247 which might be equivalent to but not equal to T in case of
8248 constrained partial specializations. */
8250 tree
8252 {
8260 /* We start looking from 1 because entry 0 is from global scope,
8261 and has no type. */
8263 {
8264 tree c;
8267 else
8268 {
8272 }
8277 }
8279 }
8281 /* If either current_class_type or one of its enclosing classes are derived
8282 from T, return the appropriate type. Used to determine how we found
8283 something via unqualified lookup. */
8285 tree
8287 {
8290 /* The bases of a dependent type are unknown. */
8301 {
8306 }
8309 }
8311 /* Return the outermost enclosing class type that is still open, or
8312 NULL_TREE. */
8314 tree
8316 {
8323 {
8330 }
8332 }
8334 /* Returns the innermost class type which is not a lambda closure type. */
8336 tree
8338 {
8343 }
8345 /* When entering a class scope, all enclosing class scopes' names with
8346 static meaning (static variables, static functions, types and
8347 enumerators) have to be visible. This recursive function calls
8348 pushclass for all enclosing class contexts until global or a local
8349 scope is reached. TYPE is the enclosed class. */
8351 void
8353 {
8354 /* A namespace might be passed in error cases, like A::B:C. */
8362 }
8364 /* Undoes a push_nested_class call. */
8366 void
8368 {
8374 }
8376 /* Returns the number of extern "LANG" blocks we are nested within. */
8378 int
8380 {
8382 }
8384 /* Set global variables CURRENT_LANG_NAME to appropriate value
8385 so that behavior of name-mangling machinery is correct. */
8387 void
8389 {
8396 else
8398 }
8400 /* Get out of the current language scope. */
8402 void
8404 {
8406 }
8407 \f
8408 /* Type instantiation routines. */
8410 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
8411 matches the TARGET_TYPE. If there is no satisfactory match, return
8412 error_mark_node, and issue an error & warning messages under
8413 control of FLAGS. Permit pointers to member function if FLAGS
8414 permits. If TEMPLATE_ONLY, the name of the overloaded function was
8415 a template-id, and EXPLICIT_TARGS are the explicitly provided
8416 template arguments.
8418 If OVERLOAD is for one or more member functions, then ACCESS_PATH
8419 is the base path used to reference those member functions. If
8420 the address is resolved to a member function, access checks will be
8421 performed and errors issued if appropriate. */
8423 static tree
8425 tree overload,
8426 tsubst_flags_t complain,
8428 tree explicit_targs,
8429 tree access_path)
8430 {
8431 /* Here's what the standard says:
8433 [over.over]
8435 If the name is a function template, template argument deduction
8436 is done, and if the argument deduction succeeds, the deduced
8437 arguments are used to generate a single template function, which
8438 is added to the set of overloaded functions considered.
8440 Non-member functions and static member functions match targets of
8441 type "pointer-to-function" or "reference-to-function." Nonstatic
8442 member functions match targets of type "pointer-to-member
8443 function;" the function type of the pointer to member is used to
8444 select the member function from the set of overloaded member
8445 functions. If a non-static member function is selected, the
8446 reference to the overloaded function name is required to have the
8447 form of a pointer to member as described in 5.3.1.
8449 If more than one function is selected, any template functions in
8450 the set are eliminated if the set also contains a non-template
8451 function, and any given template function is eliminated if the
8452 set contains a second template function that is more specialized
8453 than the first according to the partial ordering rules 14.5.5.2.
8454 After such eliminations, if any, there shall remain exactly one
8455 selected function. */
8458 /* We store the matches in a TREE_LIST rooted here. The functions
8459 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
8460 interoperability with most_specialized_instantiation. */
8462 tree fn;
8463 tree target_fn_type;
8465 /* By the time we get here, we should be seeing only real
8466 pointer-to-member types, not the internal POINTER_TYPE to
8467 METHOD_TYPE representation. */
8473 /* Check that the TARGET_TYPE is reasonable. */
8478 /* This is OK, too. */
8481 /* This is OK, too. This comes from a conversion to reference
8482 type. */
8484 else
8485 {
8491 }
8493 /* Non-member functions and static member functions match targets of type
8494 "pointer-to-function" or "reference-to-function." Nonstatic member
8495 functions match targets of type "pointer-to-member-function;" the
8496 function type of the pointer to member is used to select the member
8497 function from the set of overloaded member functions.
8499 So figure out the FUNCTION_TYPE that we want to match against. */
8502 /* If we can find a non-template function that matches, we can just
8503 use it. There's no point in generating template instantiations
8504 if we're just going to throw them out anyhow. But, of course, we
8505 can only do this when we don't *need* a template function. */
8508 {
8512 /* We're not looking for templates just yet. */
8516 /* We're looking for a non-static member, and this isn't
8517 one, or vice versa. */
8520 /* Constraints must be satisfied. This is done before
8521 return type deduction since that instantiates the
8522 function. */
8527 {
8528 /* Force instantiation to do return type deduction. */
8531 }
8533 /* In C++17 we need the noexcept-qualifier to compare types. */
8538 /* See if there's a match. */
8543 }
8545 /* Now, if we've already got a match (or matches), there's no need
8546 to proceed to the template functions. But, if we don't have a
8547 match we need to look at them, too. */
8549 {
8550 tree target_arg_types;
8551 tree target_ret_type;
8554 tree arg;
8568 {
8570 tree instantiation;
8571 tree targs;
8574 /* We're only looking for templates. */
8579 /* We're not looking for a non-static member, and this is
8580 one, or vice versa. */
8585 /* If the template has a deduced return type, don't expose it to
8586 template argument deduction. */
8590 /* Try to do argument deduction. */
8597 /* Instantiation failed. */
8600 /* Constraints must be satisfied. This is done before
8601 return type deduction since that instantiates the
8602 function. */
8606 /* And now force instantiation to do return type deduction. */
8608 {
8614 }
8616 /* In C++17 we need the noexcept-qualifier to compare types. */
8620 /* See if there's a match. */
8625 }
8627 /* Now, remove all but the most specialized of the matches. */
8629 {
8634 NULL_TREE,
8635 NULL_TREE);
8636 }
8637 }
8639 /* Now we should have exactly one function in MATCHES. */
8641 {
8642 /* There were *no* matches. */
8644 {
8649 }
8651 }
8653 {
8654 /* There were too many matches. First check if they're all
8655 the same function. */
8660 /* For multi-versioned functions, more than one match is just fine and
8661 decls_match will return false as they are different. */
8669 {
8671 {
8675 /* Since print_candidates expects the functions in the
8676 TREE_VALUE slot, we flip them here. */
8681 }
8684 }
8685 }
8687 /* Good, exactly one match. Now, convert it to the correct type. */
8692 {
8698 auto_diagnostic_group d;
8701 {
8705 }
8706 }
8708 /* If a pointer to a function that is multi-versioned is requested, the
8709 pointer to the dispatcher function is returned instead. This works
8710 well because indirectly calling the function will dispatch the right
8711 function version at run-time. */
8713 {
8717 /* Mark all the versions corresponding to the dispatcher as used. */
8720 }
8722 /* If we're doing overload resolution purely for the purpose of
8723 determining conversion sequences, we should not consider the
8724 function used. If this conversion sequence is selected, the
8725 function will be marked as used at this point. */
8727 {
8728 /* Make =delete work with SFINAE. */
8733 }
8735 /* We could not check access to member functions when this
8736 expression was originally created since we did not know at that
8737 time to which function the expression referred. */
8739 {
8742 }
8746 else
8747 {
8748 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
8749 will mark the function as addressed, but here we must do it
8750 explicitly. */
8754 }
8755 }
8757 /* This function will instantiate the type of the expression given in
8758 RHS to match the type of LHSTYPE. If errors exist, then return
8759 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
8760 we complain on errors. If we are not complaining, never modify rhs,
8761 as overload resolution wants to try many possible instantiations, in
8762 the hope that at least one will work.
8764 For non-recursive calls, LHSTYPE should be a function, pointer to
8765 function, or a pointer to member function. */
8767 tree
8769 {
8778 {
8782 }
8785 {
8794 /* Microsoft allows `A::f' to be resolved to a
8795 pointer-to-member. */
8796 ;
8797 else
8798 {
8803 }
8804 }
8806 /* If we instantiate a template, and it is a A ?: C expression
8807 with omitted B, look through the SAVE_EXPR. */
8812 {
8815 }
8817 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
8818 deduce any type information. */
8820 {
8824 }
8826 /* There are only a few kinds of expressions that may have a type
8827 dependent on overload resolution. */
8833 /* This should really only be used when attempting to distinguish
8834 what sort of a pointer to function we have. For now, any
8835 arithmetic operation which is not supported on pointers
8836 is rejected as an error. */
8839 {
8841 {
8847 /* Do not lose object's side effects. */
8851 }
8858 /* This can happen if we are forming a pointer-to-member for a
8859 member template. */
8862 /* Fall through. */
8865 {
8869 return
8873 }
8877 return
8881 access_path);
8884 {
8889 }
8896 }
8898 }
8899 \f
8900 /* Return the name of the virtual function pointer field
8901 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8902 this may have to look back through base types to find the
8903 ultimate field name. (For single inheritance, these could
8904 all be the same name. Who knows for multiple inheritance). */
8906 static tree
8908 {
8914 {
8920 }
8928 }
8930 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8931 according to [class]:
8932 The class-name is also inserted
8933 into the scope of the class itself. For purposes of access checking,
8934 the inserted class name is treated as if it were a public member name. */
8936 void
8938 {
8956 }
8958 /* Returns 1 if TYPE contains only padding bytes. */
8960 int
8962 {
8970 }
8972 /* Returns true if TYPE contains no actual data, just various
8973 possible combinations of empty classes. If IGNORE_VPTR is true,
8974 a vptr doesn't prevent the class from being considered empty. Typically
8975 we want to ignore the vptr on assignment, and not on initialization. */
8977 bool
8979 {
8981 {
8982 tree field;
8983 tree binfo;
8984 tree base_binfo;
8987 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8988 out, but we'd like to be able to check this before then. */
9002 /* An unnamed bit-field is not a data member. */
9007 }
9012 }
9014 /* Note that NAME was looked up while the current class was being
9015 defined and that the result of that lookup was DECL. */
9017 void
9019 {
9020 /* If we're not defining a class, there's nothing to do. */
9031 /* Record the binding in the names_used tables for classes inside blev. */
9033 {
9035 ? current_class_type
9039 {
9041 /* We found the declaration. */
9044 /* This class is inside the declaration scope. */
9046 }
9058 }
9059 }
9061 /* Note that NAME was declared (as DECL) in the current class. Check
9062 to see that the declaration is valid under [class.member.lookup]:
9064 If [the result of a search in T for N at point P] differs from the result of
9065 a search in T for N from immediately after the class-specifier of T, the
9066 program is ill-formed, no diagnostic required. */
9068 void
9070 {
9071 splay_tree names_used;
9072 splay_tree_node n;
9074 /* Look to see if we ever used this name. */
9075 names_used
9079 /* The C language allows members to be declared with a type of the same
9080 name, and the C++ standard says this diagnostic is not required. So
9081 allow it in extern "C" blocks unless pedantic is specified.
9082 Allow it in all cases if -ms-extensions is specified. */
9088 {
9092 /* [basic.scope.class]
9094 A name N used in a class S shall refer to the same declaration
9095 in its context and when re-evaluated in the completed scope of
9096 S. */
9104 else
9105 /* Make it an error. */
9110 {
9113 }
9114 }
9115 }
9117 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
9118 Secondary vtables are merged with primary vtables; this function
9119 will return the VAR_DECL for the primary vtable. */
9121 tree
9123 {
9124 tree decl;
9128 {
9131 }
9135 }
9138 /* Returns the binfo for the primary base of BINFO. If the resulting
9139 BINFO is a virtual base, and it is inherited elsewhere in the
9140 hierarchy, then the returned binfo might not be the primary base of
9141 BINFO in the complete object. Check BINFO_PRIMARY_P or
9142 BINFO_LOST_PRIMARY_P to be sure. */
9144 static tree
9146 {
9147 tree primary_base;
9154 }
9156 /* As above, but iterate until we reach the binfo that actually provides the
9157 vptr for BINFO. */
9159 static tree
9161 {
9165 {
9170 }
9172 }
9174 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
9175 type. Note that the virtual inheritance might be above or below BINFO in
9176 the hierarchy. */
9178 bool
9180 {
9184 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
9185 a morally virtual base. */
9188 }
9190 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
9192 static int
9194 {
9198 }
9200 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
9201 INDENT should be zero when called from the top level; it is
9202 incremented recursively. IGO indicates the next expected BINFO in
9203 inheritance graph ordering. */
9205 static tree
9207 dump_flags_t flags,
9208 tree binfo,
9209 tree igo,
9211 {
9213 tree base_binfo;
9220 {
9223 }
9237 {
9241 TFF_PLAIN_IDENTIFIER),
9243 }
9245 {
9248 }
9253 {
9257 {
9261 TFF_PLAIN_IDENTIFIER));
9262 }
9264 {
9268 TFF_PLAIN_IDENTIFIER));
9269 }
9271 {
9275 TFF_PLAIN_IDENTIFIER));
9276 }
9278 {
9282 TFF_PLAIN_IDENTIFIER));
9283 }
9287 }
9293 }
9295 /* Dump the BINFO hierarchy for T. */
9297 static void
9299 {
9311 }
9313 /* Debug interface to hierarchy dumping. */
9315 void
9317 {
9319 }
9321 static void
9323 {
9324 dump_flags_t flags;
9326 {
9329 }
9330 }
9332 static void
9334 {
9335 tree value;
9337 HOST_WIDE_INT elt;
9345 TFF_PLAIN_IDENTIFIER));
9352 }
9354 static void
9356 {
9357 dump_flags_t flags;
9364 {
9371 {
9376 }
9380 }
9383 }
9385 static void
9387 {
9388 dump_flags_t flags;
9395 {
9400 }
9403 }
9405 /* Dump a function or thunk and its thunkees. */
9407 static void
9409 {
9412 tree thunks;
9420 {
9430 else
9436 }
9440 }
9442 /* Dump the thunks for FN. */
9444 void
9446 {
9448 }
9450 /* Virtual function table initialization. */
9452 /* Create all the necessary vtables for T and its base classes. */
9454 static void
9456 {
9457 tree vbase;
9461 /* We lay out the primary and secondary vtables in one contiguous
9462 vtable. The primary vtable is first, followed by the non-virtual
9463 secondary vtables in inheritance graph order. */
9467 /* Then come the virtual bases, also in inheritance graph order. */
9469 {
9473 }
9477 }
9479 /* Initialize the vtable for BINFO with the INITS. */
9481 static void
9483 {
9484 tree decl;
9490 }
9492 /* Build the VTT (virtual table table) for T.
9493 A class requires a VTT if it has virtual bases.
9495 This holds
9496 1 - primary virtual pointer for complete object T
9497 2 - secondary VTTs for each direct non-virtual base of T which requires a
9498 VTT
9499 3 - secondary virtual pointers for each direct or indirect base of T which
9500 has virtual bases or is reachable via a virtual path from T.
9501 4 - secondary VTTs for each direct or indirect virtual base of T.
9503 Secondary VTTs look like complete object VTTs without part 4. */
9505 static void
9507 {
9508 tree type;
9509 tree vtt;
9510 tree index;
9513 /* Build up the initializers for the VTT. */
9518 /* If we didn't need a VTT, we're done. */
9522 /* Figure out the type of the VTT. */
9526 /* Now, build the VTT object itself. */
9529 /* Add the VTT to the vtables list. */
9534 }
9536 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
9537 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
9538 and CHAIN the vtable pointer for this binfo after construction is
9539 complete. VALUE can also be another BINFO, in which case we recurse. */
9541 static tree
9543 {
9544 tree vt;
9547 {
9553 else
9555 }
9558 }
9560 /* Data for secondary VTT initialization. */
9561 struct secondary_vptr_vtt_init_data
9562 {
9563 /* Is this the primary VTT? */
9566 /* Current index into the VTT. */
9567 tree index;
9569 /* Vector of initializers built up. */
9572 /* The type being constructed by this secondary VTT. */
9573 tree type_being_constructed;
9574 };
9576 /* Recursively build the VTT-initializer for BINFO (which is in the
9577 hierarchy dominated by T). INITS points to the end of the initializer
9578 list to date. INDEX is the VTT index where the next element will be
9579 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
9580 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
9581 for virtual bases of T. When it is not so, we build the constructor
9582 vtables for the BINFO-in-T variant. */
9584 static void
9587 {
9589 tree b;
9590 tree init;
9591 secondary_vptr_vtt_init_data data;
9594 /* We only need VTTs for subobjects with virtual bases. */
9598 /* We need to use a construction vtable if this is not the primary
9599 VTT. */
9601 {
9604 /* Record the offset in the VTT where this sub-VTT can be found. */
9606 }
9608 /* Add the address of the primary vtable for the complete object. */
9612 {
9615 }
9618 /* Recursively add the secondary VTTs for non-virtual bases. */
9623 /* Add secondary virtual pointers for all subobjects of BINFO with
9624 either virtual bases or reachable along a virtual path, except
9625 subobjects that are non-virtual primary bases. */
9635 /* data.inits might have grown as we added secondary virtual pointers.
9636 Make sure our caller knows about the new vector. */
9640 /* Add the secondary VTTs for virtual bases in inheritance graph
9641 order. */
9643 {
9648 }
9649 else
9650 /* Remove the ctor vtables we created. */
9652 }
9654 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
9655 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
9657 static tree
9659 {
9662 /* We don't care about bases that don't have vtables. */
9666 /* We're only interested in proper subobjects of the type being
9667 constructed. */
9671 /* We're only interested in bases with virtual bases or reachable
9672 via a virtual path from the type being constructed. */
9677 /* We're not interested in non-virtual primary bases. */
9681 /* Record the index where this secondary vptr can be found. */
9683 {
9688 {
9689 /* It's a primary virtual base, and this is not a
9690 construction vtable. Find the base this is primary of in
9691 the inheritance graph, and use that base's vtable
9692 now. */
9695 }
9696 }
9698 /* Add the initializer for the secondary vptr itself. */
9701 /* Advance the vtt index. */
9706 }
9708 /* Called from build_vtt_inits via dfs_walk. After building
9709 constructor vtables and generating the sub-vtt from them, we need
9710 to restore the BINFO_VTABLES that were scribbled on. DATA is the
9711 binfo of the base whose sub vtt was generated. */
9713 static tree
9715 {
9719 /* If this class has no vtable, none of its bases do. */
9723 /* This might be a primary base, so have no vtable in this
9724 hierarchy. */
9727 /* If we scribbled the construction vtable vptr into BINFO, clear it
9728 out now. */
9734 }
9736 /* Build the construction vtable group for BINFO which is in the
9737 hierarchy dominated by T. */
9739 static void
9741 {
9742 tree type;
9743 tree vtbl;
9744 tree id;
9745 tree vbase;
9748 /* See if we've already created this construction vtable group. */
9754 /* Build a version of VTBL (with the wrong type) for use in
9755 constructing the addresses of secondary vtables in the
9756 construction vtable group. */
9759 /* Don't export construction vtables from shared libraries. Even on
9760 targets that don't support hidden visibility, this tells
9761 can_refer_decl_in_current_unit_p not to assume that it's safe to
9762 access from a different compilation unit (bz 54314). */
9770 /* Add the vtables for each of our virtual bases using the vbase in T
9771 binfo. */
9773 vbase;
9775 {
9776 tree b;
9783 }
9785 /* Figure out the type of the construction vtable. */
9792 /* Initialize the construction vtable. */
9796 }
9798 /* Add the vtbl initializers for BINFO (and its bases other than
9799 non-virtual primaries) to the list of INITS. BINFO is in the
9800 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
9801 the constructor the vtbl inits should be accumulated for. (If this
9802 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
9803 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
9804 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
9805 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
9806 but are not necessarily the same in terms of layout. */
9808 static void
9810 tree orig_binfo,
9811 tree rtti_binfo,
9812 tree vtbl,
9813 tree t,
9815 {
9817 tree base_binfo;
9822 /* If it doesn't have a vptr, we don't do anything. */
9826 /* If we're building a construction vtable, we're not interested in
9827 subobjects that don't require construction vtables. */
9833 /* Build the initializers for the BINFO-in-T vtable. */
9836 /* Walk the BINFO and its bases. We walk in preorder so that as we
9837 initialize each vtable we can figure out at what offset the
9838 secondary vtable lies from the primary vtable. We can't use
9839 dfs_walk here because we need to iterate through bases of BINFO
9840 and RTTI_BINFO simultaneously. */
9842 {
9843 /* Skip virtual bases. */
9849 inits);
9850 }
9851 }
9853 /* Called from accumulate_vtbl_inits. Adds the initializers for the
9854 BINFO vtable to L. */
9856 static void
9858 tree orig_binfo,
9859 tree rtti_binfo,
9860 tree orig_vtbl,
9861 tree t,
9863 {
9870 {
9871 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9872 primary virtual base. If it is not the same primary in
9873 the hierarchy of T, we'll need to generate a ctor vtable
9874 for it, to place at its location in T. If it is the same
9875 primary, we still need a VTT entry for the vtable, but it
9876 should point to the ctor vtable for the base it is a
9877 primary for within the sub-hierarchy of RTTI_BINFO.
9879 There are three possible cases:
9881 1) We are in the same place.
9882 2) We are a primary base within a lost primary virtual base of
9883 RTTI_BINFO.
9884 3) We are primary to something not a base of RTTI_BINFO. */
9886 tree b;
9889 /* First, look through the bases we are primary to for RTTI_BINFO
9890 or a virtual base. */
9893 {
9898 }
9899 /* If we run out of primary links, keep looking down our
9900 inheritance chain; we might be an indirect primary. */
9904 found:
9906 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9907 base B and it is a base of RTTI_BINFO, this is case 2. In
9908 either case, we share our vtable with LAST, i.e. the
9909 derived-most base within B of which we are a primary. */
9912 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9913 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9914 binfo_ctor_vtable after everything's been set up. */
9917 /* Otherwise, this is case 3 and we get our own. */
9918 }
9925 {
9926 tree index;
9929 /* Add the initializer for this vtable. */
9933 /* Figure out the position to which the VPTR should point. */
9939 }
9942 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9943 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9944 straighten this out. */
9947 /* Throw away any unneeded intializers. */
9949 else
9950 /* For an ordinary vtable, set BINFO_VTABLE. */
9952 }
9957 /* Construct the initializer for BINFO's virtual function table. BINFO
9958 is part of the hierarchy dominated by T. If we're building a
9959 construction vtable, the ORIG_BINFO is the binfo we should use to
9960 find the actual function pointers to put in the vtable - but they
9961 can be overridden on the path to most-derived in the graph that
9962 ORIG_BINFO belongs. Otherwise,
9963 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9964 BINFO that should be indicated by the RTTI information in the
9965 vtable; it will be a base class of T, rather than T itself, if we
9966 are building a construction vtable.
9968 The value returned is a TREE_LIST suitable for wrapping in a
9969 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9970 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9971 number of non-function entries in the vtable.
9973 It might seem that this function should never be called with a
9974 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9975 base is always subsumed by a derived class vtable. However, when
9976 we are building construction vtables, we do build vtables for
9977 primary bases; we need these while the primary base is being
9978 constructed. */
9980 static void
9982 tree orig_binfo,
9983 tree t,
9984 tree rtti_binfo,
9987 {
9988 tree v;
9989 vtbl_init_data vid;
9991 tree vbinfo;
9995 /* Initialize VID. */
10003 /* The first vbase or vcall offset is at index -3 in the vtable. */
10006 /* Add entries to the vtable for RTTI. */
10009 /* Create an array for keeping track of the functions we've
10010 processed. When we see multiple functions with the same
10011 signature, we share the vcall offsets. */
10013 /* Add the vcall and vbase offset entries. */
10016 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
10017 build_vbase_offset_vtbl_entries. */
10022 /* If the target requires padding between data entries, add that now. */
10024 {
10030 /* Move data entries into their new positions and add padding
10031 after the new positions. Iterate backwards so we don't
10032 overwrite entries that we would need to process later. */
10035 ix--)
10036 {
10044 {
10048 null_pointer_node);
10049 }
10050 }
10051 }
10056 /* The initializers for virtual functions were built up in reverse
10057 order. Straighten them out and add them to the running list in one
10058 step. */
10067 /* Go through all the ordinary virtual functions, building up
10068 initializers. */
10070 {
10071 tree delta;
10072 tree vcall_index;
10079 {
10083 {
10086 }
10088 }
10090 /* If the only definition of this function signature along our
10091 primary base chain is from a lost primary, this vtable slot will
10092 never be used, so just zero it out. This is important to avoid
10093 requiring extra thunks which cannot be generated with the function.
10095 We first check this in update_vtable_entry_for_fn, so we handle
10096 restored primary bases properly; we also need to do it here so we
10097 zero out unused slots in ctor vtables, rather than filling them
10098 with erroneous values (though harmless, apart from relocation
10099 costs). */
10104 {
10105 /* Pull the offset for `this', and the function to call, out of
10106 the list. */
10113 /* You can't call an abstract virtual function; it's abstract.
10114 So, we replace these functions with __pure_virtual. */
10116 {
10119 {
10121 abort_fndecl_addr
10125 }
10126 }
10127 /* Likewise for deleted virtuals. */
10129 {
10131 {
10135 dvirt_fn = push_library_fn
10139 }
10144 }
10145 else
10146 {
10148 {
10153 }
10154 /* Take the address of the function, considering it to be of an
10155 appropriate generic type. */
10159 /* Don't refer to a virtual destructor from a constructor
10160 vtable or a vtable for an abstract class, since destroying
10161 an object under construction is undefined behavior and we
10162 don't want it to be considered a candidate for speculative
10163 devirtualization. But do create the thunk for ABI
10164 compliance. */
10169 }
10170 }
10172 /* And add it to the chain of initializers. */
10174 {
10179 else
10181 {
10187 }
10188 }
10189 else
10191 }
10192 }
10194 /* Adds to vid->inits the initializers for the vbase and vcall
10195 offsets in BINFO, which is in the hierarchy dominated by T. */
10197 static void
10199 {
10200 tree b;
10202 /* If this is a derived class, we must first create entries
10203 corresponding to the primary base class. */
10208 /* Add the vbase entries for this base. */
10210 /* Add the vcall entries for this base. */
10212 }
10214 /* Returns the initializers for the vbase offset entries in the vtable
10215 for BINFO (which is part of the class hierarchy dominated by T), in
10216 reverse order. VBASE_OFFSET_INDEX gives the vtable index
10217 where the next vbase offset will go. */
10219 static void
10221 {
10222 tree vbase;
10223 tree t;
10224 tree non_primary_binfo;
10226 /* If there are no virtual baseclasses, then there is nothing to
10227 do. */
10233 /* We might be a primary base class. Go up the inheritance hierarchy
10234 until we find the most derived class of which we are a primary base:
10235 it is the offset of that which we need to use. */
10238 {
10239 tree b;
10241 /* If we have reached a virtual base, then it must be a primary
10242 base (possibly multi-level) of vid->binfo, or we wouldn't
10243 have called build_vcall_and_vbase_vtbl_entries for it. But it
10244 might be a lost primary, so just skip down to vid->binfo. */
10246 {
10249 }
10255 }
10257 /* Go through the virtual bases, adding the offsets. */
10259 vbase;
10261 {
10262 tree b;
10263 tree delta;
10268 /* Find the instance of this virtual base in the complete
10269 object. */
10272 /* If we've already got an offset for this virtual base, we
10273 don't need another one. */
10278 /* Figure out where we can find this vbase offset. */
10287 /* The vbase offset had better be the same. */
10290 /* The next vbase will come at a more negative offset. */
10294 /* The initializer is the delta from BINFO to this virtual base.
10295 The vbase offsets go in reverse inheritance-graph order, and
10296 we are walking in inheritance graph order so these end up in
10297 the right order. */
10304 }
10305 }
10307 /* Adds the initializers for the vcall offset entries in the vtable
10308 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
10309 to VID->INITS. */
10311 static void
10313 {
10314 /* We only need these entries if this base is a virtual base. We
10315 compute the indices -- but do not add to the vtable -- when
10316 building the main vtable for a class. */
10319 /* If BINFO is RTTI_BINFO, then (since BINFO does not
10320 correspond to VID->DERIVED), we are building a primary
10321 construction virtual table. Since this is a primary
10322 virtual table, we do not need the vcall offsets for
10323 BINFO. */
10325 {
10326 /* We need a vcall offset for each of the virtual functions in this
10327 vtable. For example:
10329 class A { virtual void f (); };
10330 class B1 : virtual public A { virtual void f (); };
10331 class B2 : virtual public A { virtual void f (); };
10332 class C: public B1, public B2 { virtual void f (); };
10334 A C object has a primary base of B1, which has a primary base of A. A
10335 C also has a secondary base of B2, which no longer has a primary base
10336 of A. So the B2-in-C construction vtable needs a secondary vtable for
10337 A, which will adjust the A* to a B2* to call f. We have no way of
10338 knowing what (or even whether) this offset will be when we define B2,
10339 so we store this "vcall offset" in the A sub-vtable and look it up in
10340 a "virtual thunk" for B2::f.
10342 We need entries for all the functions in our primary vtable and
10343 in our non-virtual bases' secondary vtables. */
10345 /* If we are just computing the vcall indices -- but do not need
10346 the actual entries -- not that. */
10349 /* Now, walk through the non-virtual bases, adding vcall offsets. */
10351 }
10352 }
10354 /* Build vcall offsets, starting with those for BINFO. */
10356 static void
10358 {
10360 tree primary_binfo;
10361 tree base_binfo;
10363 /* Don't walk into virtual bases -- except, of course, for the
10364 virtual base for which we are building vcall offsets. Any
10365 primary virtual base will have already had its offsets generated
10366 through the recursion in build_vcall_and_vbase_vtbl_entries. */
10370 /* If BINFO has a primary base, process it first. */
10375 /* Add BINFO itself to the list. */
10378 /* Scan the non-primary bases of BINFO. */
10382 }
10384 /* Called from build_vcall_offset_vtbl_entries_r. */
10386 static void
10388 {
10389 /* Make entries for the rest of the virtuals. */
10390 tree orig_fn;
10392 /* The ABI requires that the methods be processed in declaration
10393 order. */
10395 orig_fn;
10399 }
10401 /* Add a vcall offset entry for ORIG_FN to the vtable. */
10403 static void
10405 {
10407 tree vcall_offset;
10408 tree derived_entry;
10410 /* If there is already an entry for a function with the same
10411 signature as FN, then we do not need a second vcall offset.
10412 Check the list of functions already present in the derived
10413 class vtable. */
10415 {
10417 /* We only use one vcall offset for virtual destructors,
10418 even though there are two virtual table entries. */
10422 }
10424 /* If we are building these vcall offsets as part of building
10425 the vtable for the most derived class, remember the vcall
10426 offset. */
10428 {
10431 }
10433 /* The next vcall offset will be found at a more negative
10434 offset. */
10438 /* Keep track of this function. */
10442 {
10443 tree base;
10444 tree fn;
10446 /* Find the overriding function. */
10450 else
10451 {
10454 /* The vbase we're working on is a primary base of
10455 vid->binfo. But it might be a lost primary, so its
10456 BINFO_OFFSET might be wrong, so we just use the
10457 BINFO_OFFSET from vid->binfo. */
10463 vcall_offset);
10464 }
10465 /* Add the initializer to the vtable. */
10467 }
10468 }
10470 /* Return vtbl initializers for the RTTI entries corresponding to the
10471 BINFO's vtable. The RTTI entries should indicate the object given
10472 by VID->rtti_binfo. */
10474 static void
10476 {
10477 tree b;
10478 tree t;
10479 tree offset;
10480 tree decl;
10481 tree init;
10485 /* To find the complete object, we will first convert to our most
10486 primary base, and then add the offset in the vtbl to that value. */
10491 /* The second entry is the address of the typeinfo object. */
10494 else
10497 /* Convert the declaration to a type that can be stored in the
10498 vtable. */
10502 /* Add the offset-to-top entry. It comes earlier in the vtable than
10503 the typeinfo entry. Convert the offset to look like a
10504 function pointer, so that we can put it in the vtable. */
10507 }
10509 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
10510 accessibility. */
10512 bool
10514 {
10517 }
10519 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
10521 bool
10523 {
10527 }
10529 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
10530 class between them, if any. */
10532 tree
10534 {
10546 {
10549 }
10553 }