| blob | 1789d1ecb70ad34a9637fc5198a3169af5bb533e |
1 /* Functions related to building classes and their related objects.
2 Copyright (C) 1987-2018 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. */
114 /* An array of all local classes present in this translation unit, in
115 declaration order. */
147 /* Used by find_flexarrays and related functions. */
196 tree *);
205 splay_tree_key k2);
214 /* Return a COND_EXPR that executes TRUE_STMT if this execution of the
215 'structor is in charge of 'structing virtual bases, or FALSE_STMT
216 otherwise. */
218 tree
220 {
230 }
232 /* Convert to or from a base subobject. EXPR is an expression of type
233 `A' or `A*', an expression of type `B' or `B*' is returned. To
234 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
235 the B base instance within A. To convert base A to derived B, CODE
236 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
237 In this latter case, A must not be a morally virtual base of B.
238 NONNULL is true if EXPR is known to be non-NULL (this is only
239 needed when EXPR is of pointer type). CV qualifiers are preserved
240 from EXPR. */
242 tree
244 tree expr,
245 tree binfo,
247 tsubst_flags_t complain)
248 {
251 tree probe;
252 tree offset;
253 tree target_type;
255 tree ptr_target_type;
266 {
272 }
283 {
284 /* This can happen when adjust_result_of_qualified_name_lookup can't
285 find a unique base binfo in a call to a member function. We
286 couldn't give the diagnostic then since we might have been calling
287 a static member function, so we do it now. In other cases, eg.
288 during error recovery (c++/71979), we may not have a base at all. */
290 {
294 }
296 }
303 /* Nothing to do. */
307 {
309 {
311 {
314 "pointer to derived class %qT because the base is "
316 else
320 }
321 else
322 {
328 else
332 }
333 }
335 }
338 {
340 /* This must happen before the call to save_expr. */
342 }
343 else
349 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
350 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
351 expression returned matches the input. */
352 target_type = cp_build_qualified_type
356 /* Do we need to look in the vtable for the real offset? */
359 /* Don't bother with the calculations inside sizeof; they'll ICE if the
360 source type is incomplete and the pointer value doesn't matter. In a
361 template (even in instantiate_non_dependent_expr), we don't have vtables
362 set up properly yet, and the value doesn't matter there either; we're
363 just interested in the result of overload resolution. */
365 || processing_template_decl
367 {
370 }
373 {
379 }
381 /* If we're in an NSDMI, we don't have the full constructor context yet
382 that we need for converting to a virtual base, so just build a stub
383 CONVERT_EXPR and expand it later in bot_replace. */
386 {
390 }
392 /* Do we need to check for a null pointer? */
394 {
395 /* If we know the conversion will not actually change the value
396 of EXPR, then we can avoid testing the expression for NULL.
397 We have to avoid generating a COMPONENT_REF for a base class
398 field, because other parts of the compiler know that such
399 expressions are always non-NULL. */
403 }
405 /* Protect against multiple evaluation if necessary. */
409 /* Now that we've saved expr, build the real null test. */
411 {
415 /* This is a compiler generated comparison, don't emit
416 e.g. -Wnonnull-compare warning for it. */
418 }
420 /* If this is a simple base reference, express it as a COMPONENT_REF. */
422 /* We don't build base fields for empty bases, and they aren't very
423 interesting to the optimizers anyway. */
425 {
434 }
437 {
438 /* Going via virtual base V_BINFO. We need the static offset
439 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
440 V_BINFO. That offset is an entry in D_BINFO's vtable. */
441 tree v_offset;
444 {
445 /* In a base member initializer, we cannot rely on the
446 vtable being set up. We have to indirect via the
447 vtt_parm. */
448 tree t;
454 }
455 else
456 {
460 {
465 }
468 }
476 v_offset);
488 /* Negative fixed_type_p means this is a constructor or destructor;
489 virtual base layout is fixed in in-charge [cd]tors, but not in
490 base [cd]tors. */
491 offset = build_if_in_charge
493 v_offset);
494 else
496 }
504 {
509 }
510 else
513 indout:
515 {
519 }
521 out:
527 }
529 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
530 Perform a derived-to-base conversion by recursively building up a
531 sequence of COMPONENT_REFs to the appropriate base fields. */
533 static tree
535 {
538 tree field;
541 {
542 tree temp;
546 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
547 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
548 an lvalue in the front end; only _DECLs and _REFs are lvalues
549 in the back end. */
555 }
557 /* Recurse. */
562 /* Is this the base field created by build_base_field? */
566 /* If we're looking for a field in the most-derived class,
567 also check the field offset; we can have two base fields
568 of the same type if one is an indirect virtual base and one
569 is a direct non-virtual base. */
573 {
574 /* We don't use build_class_member_access_expr here, as that
575 has unnecessary checks, and more importantly results in
576 recursive calls to dfs_walk_once. */
582 /* Mark the expression const or volatile, as appropriate.
583 Even though we've dealt with the type above, we still have
584 to mark the expression itself. */
591 }
593 /* Didn't find the base field?!? */
595 }
597 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
598 type is a class type or a pointer to a class type. In the former
599 case, TYPE is also a class type; in the latter it is another
600 pointer type. If CHECK_ACCESS is true, an error message is emitted
601 if TYPE is inaccessible. If OBJECT has pointer type, the value is
602 assumed to be non-NULL. */
604 tree
606 tsubst_flags_t complain)
607 {
608 tree binfo;
609 tree object_type;
612 {
615 }
616 else
625 }
627 /* EXPR is an expression with unqualified class type. BASE is a base
628 binfo of that class type. Returns EXPR, converted to the BASE
629 type. This function assumes that EXPR is the most derived class;
630 therefore virtual bases can be found at their static offsets. */
632 tree
634 {
635 tree expr_type;
639 {
640 /* If this is a non-empty base, use a COMPONENT_REF. */
644 /* We use fold_build2 and fold_convert below to simplify the trees
645 provided to the optimizers. It is not safe to call these functions
646 when processing a template because they do not handle C++-specific
647 trees. */
655 }
658 }
660 \f
661 tree
663 {
667 /* Can happen in case of duplicate base types (c++/59082). */
671 /* First, convert to the requested type. */
676 /* Second, the requested type may not be the owner of its own vptr.
677 If not, convert to the base class that owns it. We cannot use
678 convert_to_base here, because VCONTEXT may appear more than once
679 in the inheritance hierarchy of TYPE, and thus direct conversion
680 between the types may be ambiguous. Following the path back up
681 one step at a time via primary bases avoids the problem. */
685 {
688 }
691 }
693 /* Given an object INSTANCE, return an expression which yields the
694 vtable element corresponding to INDEX. There are many special
695 cases for INSTANCE which we take care of here, mainly to avoid
696 creating extra tree nodes when we don't have to. */
698 tree
700 {
701 tree aref;
704 /* Try to figure out what a reference refers to, and
705 access its virtual function table directly. */
713 {
718 }
727 }
729 /* Given a stable object pointer INSTANCE_PTR, return an expression which
730 yields a function pointer corresponding to vtable element INDEX. */
732 tree
734 {
735 tree aref;
739 /* When using function descriptors, the address of the
740 vtable entry is treated as a function pointer. */
745 /* Remember this as a method reference, for later devirtualization. */
749 }
751 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
752 for the given TYPE. */
754 static tree
756 {
758 }
760 /* DECL is an entity associated with TYPE, like a virtual table or an
761 implicitly generated constructor. Determine whether or not DECL
762 should have external or internal linkage at the object file
763 level. This routine does not deal with COMDAT linkage and other
764 similar complexities; it simply sets TREE_PUBLIC if it possible for
765 entities in other translation units to contain copies of DECL, in
766 the abstract. */
768 void
770 {
773 }
775 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
776 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
777 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
779 static tree
781 {
782 tree decl;
785 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
786 now to avoid confusion in mangle_decl. */
797 /* The vtable has not been defined -- yet. */
801 /* Mark the VAR_DECL node representing the vtable itself as a
802 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
803 is rather important that such things be ignored because any
804 effort to actually generate DWARF for them will run into
805 trouble when/if we encounter code like:
807 #pragma interface
808 struct S { virtual void member (); };
810 because the artificial declaration of the vtable itself (as
811 manufactured by the g++ front end) will say that the vtable is
812 a static member of `S' but only *after* the debug output for
813 the definition of `S' has already been output. This causes
814 grief because the DWARF entry for the definition of the vtable
815 will try to refer back to an earlier *declaration* of the
816 vtable as a static member of `S' and there won't be one. We
817 might be able to arrange to have the "vtable static member"
818 attached to the member list for `S' before the debug info for
819 `S' get written (which would solve the problem) but that would
820 require more intrusive changes to the g++ front end. */
824 }
826 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
827 or even complete. If this does not exist, create it. If COMPLETE is
828 nonzero, then complete the definition of it -- that will render it
829 impossible to actually build the vtable, but is useful to get at those
830 which are known to exist in the runtime. */
832 tree
834 {
835 tree decl;
844 {
847 }
850 }
852 /* Build the primary virtual function table for TYPE. If BINFO is
853 non-NULL, build the vtable starting with the initial approximation
854 that it is the same as the one which is the head of the association
855 list. Returns a nonzero value if a new vtable is actually
856 created. */
858 static int
860 {
861 tree decl;
862 tree virtuals;
867 {
869 /* We have already created a vtable for this base, so there's
870 no need to do it again. */
877 }
878 else
879 {
882 }
884 /* Initialize the association list for this type, based
885 on our first approximation. */
890 }
892 /* Give BINFO a new virtual function table which is initialized
893 with a skeleton-copy of its original initialization. The only
894 entry that changes is the `delta' entry, so we can really
895 share a lot of structure.
897 FOR_TYPE is the most derived type which caused this table to
898 be needed.
900 Returns nonzero if we haven't met BINFO before.
902 The order in which vtables are built (by calling this function) for
903 an object must remain the same, otherwise a binary incompatibility
904 can result. */
906 static int
908 {
910 /* We already created a vtable for this base. There's no need to
911 do it again. */
914 /* Remember that we've created a vtable for this BINFO, so that we
915 don't try to do so again. */
918 /* Make fresh virtual list, so we can smash it later. */
921 /* Secondary vtables are laid out as part of the same structure as
922 the primary vtable. */
925 }
927 /* Create a new vtable for BINFO which is the hierarchy dominated by
928 T. Return nonzero if we actually created a new vtable. */
930 static int
932 {
934 /* In this case, it is *type*'s vtable we are modifying. We start
935 with the approximation that its vtable is that of the
936 immediate base class. */
938 else
939 /* This is our very own copy of `basetype' to play with. Later,
940 we will fill in all the virtual functions that override the
941 virtual functions in these base classes which are not defined
942 by the current type. */
944 }
946 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
947 (which is in the hierarchy dominated by T) list FNDECL as its
948 BV_FN. DELTA is the required constant adjustment from the `this'
949 pointer where the vtable entry appears to the `this' required when
950 the function is actually called. */
952 static void
954 tree binfo,
955 tree fndecl,
956 tree delta,
958 {
959 tree v;
965 {
966 /* We need a new vtable for BINFO. */
968 {
969 /* If we really did make a new vtable, we also made a copy
970 of the BINFO_VIRTUALS list. Now, we have to find the
971 corresponding entry in that list. */
976 }
981 }
982 }
984 \f
985 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
986 METHOD is being injected via a using_decl. Returns true if the
987 method could be added to the method vec. */
989 bool
991 {
1000 /* Check to see if we've already got this method. */
1002 {
1004 tree fn_type;
1005 tree method_type;
1006 tree parms1;
1007 tree parms2;
1012 /* Two using-declarations can coexist, we'll complain about ambiguity in
1013 overload resolution. */
1015 /* Except handle inherited constructors specially. */
1019 /* [over.load] Member function declarations with the
1020 same name and the same parameter types cannot be
1021 overloaded if any of them is a static member
1022 function declaration.
1024 [over.load] Member function declarations with the same name and
1025 the same parameter-type-list as well as member function template
1026 declarations with the same name, the same parameter-type-list, and
1027 the same template parameter lists cannot be overloaded if any of
1028 them, but not all, have a ref-qualifier.
1030 [namespace.udecl] When a using-declaration brings names
1031 from a base class into a derived class scope, member
1032 functions in the derived class override and/or hide member
1033 functions with the same name and parameter types in a base
1034 class (rather than conflicting). */
1040 /* Compare the quals on the 'this' parm. Don't compare
1041 the whole types, as used functions are treated as
1042 coming from the using class in overload resolution. */
1045 /* Either both or neither need to be ref-qualified for
1046 differing quals to allow overloading. */
1053 /* For templates, the return type and template parameters
1054 must be identical. */
1067 /* Bring back parameters omitted from an inherited ctor. */
1078 {
1079 /* If these are versions of the same function, process and
1080 move on. */
1086 {
1088 {
1092 {
1094 {
1095 /* Inheriting the same constructor along different
1096 paths, combine them. */
1097 SET_DECL_INHERITED_CTOR
1100 /* And discard the new one. */
1102 }
1103 else
1104 /* Inherited ctors can coexist until overload
1105 resolution. */
1107 }
1113 basef);
1114 }
1115 /* Otherwise defer to the other function. */
1117 }
1120 /* Defer to the local function. */
1124 {
1125 /* Remove the inherited constructor. */
1128 }
1129 else
1130 {
1136 }
1137 }
1138 }
1140 /* A class should never have more than one destructor. */
1152 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1158 }
1160 /* Subroutines of finish_struct. */
1162 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1163 legit, otherwise return 0. */
1165 static int
1167 {
1168 tree elem;
1176 {
1178 {
1182 else
1185 }
1186 else
1187 {
1188 /* They're changing the access to the same thing they changed
1189 it to before. That's OK. */
1190 ;
1191 }
1192 }
1193 else
1194 {
1196 tf_warning_or_error);
1199 }
1201 }
1203 /* Return the access node for DECL's access in its enclosing class. */
1205 tree
1207 {
1211 }
1213 /* Process the USING_DECL, which is a member of T. */
1215 static void
1217 {
1222 tree old_value;
1227 tf_warning_or_error);
1229 {
1234 else
1236 }
1244 ;
1246 {
1248 /* It's OK to use functions from a base when there are functions with
1250 else
1251 {
1258 }
1259 }
1261 {
1268 }
1270 /* Make type T see field decl FDECL with access ACCESS. */
1273 {
1276 }
1277 else
1279 }
1280 \f
1281 /* Data structure for find_abi_tags_r, below. */
1283 struct abi_tag_data
1284 {
1288 };
1290 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1291 in the context of P. TAG can be either an identifier (the DECL_NAME of
1292 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1294 static void
1296 {
1298 {
1300 {
1301 /* We're collecting tags from template arguments or from
1302 the type of a variable or function return type. */
1305 /* Don't inherit this tag multiple times. */
1309 {
1310 /* Tags inherited from type template arguments are only used
1311 to avoid warnings. */
1314 }
1315 /* For functions and variables we want to warn, too. */
1316 }
1318 /* Otherwise we're diagnosing missing tags. */
1320 {
1321 auto_diagnostic_group d;
1326 }
1328 {
1329 auto_diagnostic_group d;
1333 }
1335 {
1336 auto_diagnostic_group d;
1341 }
1342 else
1343 {
1344 auto_diagnostic_group d;
1348 {
1352 }
1353 }
1354 }
1355 }
1357 /* Find all the ABI tags in the attribute list ATTR and either call
1358 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1360 static void
1362 {
1369 {
1374 else
1376 }
1377 }
1379 /* Find all the ABI tags on T and its enclosing scopes and either call
1380 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1382 static void
1384 {
1386 {
1387 tree attr;
1389 {
1392 }
1393 else
1394 {
1397 }
1399 }
1400 }
1402 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1403 types with ABI tags, add the corresponding identifiers to the VEC in
1404 *DATA and set IDENTIFIER_MARKED. */
1406 static tree
1408 {
1412 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1413 anyway, but let's make sure of it. */
1421 }
1423 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1424 IDENTIFIER_MARKED on its ABI tags. */
1426 static tree
1428 {
1432 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1433 anyway, but let's make sure of it. */
1441 }
1443 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1444 scopes. */
1446 static void
1448 {
1451 {
1454 {
1455 /* Template arguments are part of the signature. */
1458 {
1461 }
1462 }
1464 /* A function's parameter types are part of the signature, so
1465 we don't need to inherit any tags that are also in them. */
1470 }
1471 }
1473 /* Check that T has all the ABI tags that subobject SUBOB has, or
1474 warn if not. If T is a (variable or function) declaration, also
1475 return any missing tags, and add them to T if JUST_CHECKING is false. */
1477 static tree
1479 {
1487 /* No need to worry about things local to this TU. */
1503 {
1506 }
1507 else
1508 {
1512 else
1515 }
1520 }
1522 /* Check that DECL has all the ABI tags that are used in parts of its type
1523 that are not reflected in its mangled name. */
1525 void
1527 {
1534 }
1536 /* Return any ABI tags that are used in parts of the type of DECL
1537 that are not reflected in its mangled name. This function is only
1538 used in backward-compatible mangling for ABI <11. */
1540 tree
1542 {
1546 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1547 that we can use this function for setting need_abi_warning
1548 regardless of the current flag_abi_version. */
1551 else
1553 }
1555 void
1557 {
1567 {
1570 {
1574 }
1575 }
1577 // If we found some tags on our template arguments, add them to our
1578 // abi_tag attribute.
1580 {
1584 else
1587 }
1590 }
1592 /* Return true, iff class T has a non-virtual destructor that is
1593 accessible from outside the class heirarchy (i.e. is public, or
1594 there's a suitable friend. */
1596 static bool
1598 {
1601 /* An implicitly declared destructor is always public. And,
1602 if it were virtual, we would have created it by now. */
1617 }
1619 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1620 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1621 properties of the bases. */
1623 static void
1627 {
1631 tree base_binfo;
1632 tree binfo;
1642 {
1651 /* If any base class is non-literal, so is the derived class. */
1655 /* If the base class doesn't have copy constructors or
1656 assignment operators that take const references, then the
1657 derived class cannot have such a member automatically
1658 generated. */
1667 /* A virtual base does not effect nearly emptiness. */
1668 ;
1670 {
1672 /* And if there is more than one nearly empty base, then the
1673 derived class is not nearly empty either. */
1675 else
1676 /* Remember we've seen one. */
1678 }
1680 /* If the base class is not empty or nearly empty, then this
1681 class cannot be nearly empty. */
1684 /* A lot of properties from the bases also apply to the derived
1685 class. */
1702 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1705 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1711 /* A standard-layout class is a class that:
1712 ...
1713 * has no non-standard-layout base classes, */
1716 {
1717 tree basefield;
1718 /* ...has no base classes of the same type as the first non-static
1719 data member... */
1721 && (same_type_ignoring_top_level_qualifiers_p
1724 else
1725 /* ...either has no non-static data members in the most-derived
1726 class and at most one base class with non-static data
1727 members, or has no base classes with non-static data
1728 members */
1734 {
1737 else
1740 }
1741 }
1743 /* Don't bother collecting tm attributes if transactional memory
1744 support is not enabled. */
1746 {
1750 }
1753 }
1755 /* If one of the base classes had TM attributes, and the current class
1756 doesn't define its own, then the current class inherits one. */
1758 {
1761 }
1762 }
1764 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1765 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1766 that have had a nearly-empty virtual primary base stolen by some
1767 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1768 T. */
1770 static void
1772 {
1776 tree base_binfo;
1778 /* Determine the primary bases of our bases. */
1781 {
1784 /* See if we're the non-virtual primary of our inheritance
1785 chain. */
1787 {
1794 /* We are the primary binfo. */
1796 }
1797 /* Determine if we have a virtual primary base, and mark it so.
1798 */
1800 {
1804 /* Someone already claimed this base. */
1806 else
1807 {
1808 tree delta;
1813 /* A virtual binfo might have been copied from within
1814 another hierarchy. As we're about to use it as a
1815 primary base, make sure the offsets match. */
1823 }
1824 }
1825 }
1827 /* First look for a dynamic direct non-virtual base. */
1829 {
1833 {
1836 }
1837 }
1839 /* A "nearly-empty" virtual base class can be the primary base
1840 class, if no non-virtual polymorphic base can be found. Look for
1841 a nearly-empty virtual dynamic base that is not already a primary
1842 base of something in the hierarchy. If there is no such base,
1843 just pick the first nearly-empty virtual base. */
1849 {
1851 {
1852 /* Found one that is not primary. */
1855 }
1857 /* Remember the first candidate. */
1859 }
1861 found:
1862 /* If we've got a primary base, use it. */
1864 {
1869 /* We are stealing a primary base. */
1873 {
1874 tree delta;
1877 /* A virtual binfo might have been copied from within
1878 another hierarchy. As we're about to use it as a primary
1879 base, make sure the offsets match. */
1884 }
1891 }
1892 }
1894 /* Update the variant types of T. */
1896 void
1898 {
1899 tree variants;
1905 variants;
1907 {
1908 /* These fields are in the _TYPE part of the node, not in
1909 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1919 /* Copy whatever these are holding today. */
1922 }
1923 }
1925 /* KLASS is a class that we're applying may_alias to after the body is
1926 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
1927 canonical type(s) will be implicitly updated. */
1929 static void
1931 {
1940 }
1942 /* Early variant fixups: we apply attributes at the beginning of the class
1943 definition, and we need to fix up any variants that have already been
1944 made via elaborated-type-specifier so that check_qualified_type works. */
1946 void
1948 {
1949 tree variants;
1963 variants;
1965 {
1966 /* These are the two fields that check_qualified_type looks at and
1967 are affected by attributes. */
1972 else
1977 }
1978 }
1979 \f
1980 /* Set memoizing fields and bits of T (and its variants) for later
1981 use. */
1983 static void
1985 {
1986 /* Fix up variants (if any). */
1990 /* For a class w/o baseclasses, 'finish_struct' has set
1991 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
1992 Similarly for a class whose base classes do not have vtables.
1993 When neither of these is true, we might have removed abstract
1994 virtuals (by providing a definition), added some (by declaring
1995 new ones), or redeclared ones from a base class. We need to
1996 recalculate what's really an abstract virtual at this point (by
1997 looking in the vtables). */
2000 /* If this type has a copy constructor or a destructor, force its
2001 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2002 nonzero. This will cause it to be passed by invisible reference
2003 and prevent it from being returned in a register. */
2006 {
2007 tree variants;
2010 {
2013 }
2014 }
2015 }
2017 /* Issue warnings about T having private constructors, but no friends,
2018 and so forth.
2020 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2021 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2022 non-private static member functions. */
2024 static void
2026 {
2032 /* If the class has friends, those entities might create and
2033 access instances, so we should not warn. */
2036 /* We will have warned when the template was declared; there's
2037 no need to warn on every instantiation. */
2039 /* There's no reason to even consider warning about this
2040 class. */
2043 /* We only issue one warning, if more than one applies, because
2044 otherwise, on code like:
2046 class A {
2047 // Oops - forgot `public:'
2048 A();
2049 A(const A&);
2050 ~A();
2051 };
2053 we warn several times about essentially the same problem. */
2055 /* Check to see if all (non-constructor, non-destructor) member
2056 functions are private. (Since there are no friends or
2057 non-private statics, we can't ever call any of the private member
2058 functions.) */
2067 /* We're not interested in compiler-generated methods; they don't
2070 {
2072 /* A non-private static member function is just like a
2073 friend; it can create and invoke private member
2074 functions, and be accessed without a class
2075 instance. */
2079 /* Keep searching for a static member function. */
2080 }
2085 {
2086 /* There are no non-private methods, and there's at least one
2087 private member function that isn't a constructor or
2088 destructor. (If all the private members are
2089 constructors/destructors we want to use the code below that
2090 issues error messages specifically referring to
2091 constructors/destructors.) */
2097 {
2100 }
2102 {
2106 }
2107 }
2109 /* Even if some of the member functions are non-private, the class
2110 won't be useful for much if all the constructors or destructors
2111 are private: such an object can never be created or destroyed. */
2114 {
2117 t);
2119 }
2121 /* Warn about classes that have private constructors and no friends. */
2123 /* Implicitly generated constructors are always public. */
2125 {
2128 /* If a non-template class does not define a copy
2129 constructor, one is defined for it, enabling it to avoid
2130 this warning. For a template class, this does not
2131 happen, and so we would normally get a warning on:
2133 template <class T> class C { private: C(); };
2135 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2136 complete non-template or fully instantiated classes have this
2137 flag set. */
2140 else
2146 /* Ideally, we wouldn't count any constructor that takes
2147 an argument of the class type as a parameter, because
2148 such things cannot be used to construct an instance of
2149 the class unless you already have one. */
2151 else
2155 {
2158 t);
2164 }
2165 }
2166 }
2168 /* Make BINFO's vtable have N entries, including RTTI entries,
2169 vbase and vcall offsets, etc. Set its type and call the back end
2170 to lay it out. */
2172 static void
2174 {
2175 tree atype;
2176 tree vtable;
2181 /* We may have to grow the vtable. */
2184 {
2188 }
2189 }
2191 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2192 have the same signature. */
2194 int
2196 {
2197 /* One destructor overrides another if they are the same kind of
2198 destructor. */
2202 /* But a non-destructor never overrides a destructor, nor vice
2203 versa, nor do different kinds of destructors override
2204 one-another. For example, a complete object destructor does not
2205 override a deleting destructor. */
2214 {
2222 }
2224 }
2226 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2227 subobject. */
2229 static bool
2231 {
2232 tree probe;
2235 {
2239 /* If we meet a virtual base, we can't follow the inheritance
2240 any more. See if the complete type of DERIVED contains
2241 such a virtual base. */
2244 }
2246 }
2249 /* The function for which we are trying to find a final overrider. */
2250 tree fn;
2251 /* The base class in which the function was declared. */
2252 tree declaring_base;
2253 /* The candidate overriders. */
2254 tree candidates;
2255 /* Path to most derived. */
2257 };
2259 /* Add the overrider along the current path to FFOD->CANDIDATES.
2260 Returns true if an overrider was found; false otherwise. */
2262 static bool
2266 {
2267 tree method;
2269 /* If BINFO is not the most derived type, try a more derived class.
2270 A definition there will overrider a definition here. */
2272 {
2273 depth--;
2277 }
2281 {
2284 /* Remove any candidates overridden by this new function. */
2286 {
2287 /* If *CANDIDATE overrides METHOD, then METHOD
2288 cannot override anything else on the list. */
2291 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2294 else
2296 }
2298 /* Add the new function. */
2301 }
2304 }
2306 /* Called from find_final_overrider via dfs_walk. */
2308 static tree
2310 {
2318 }
2320 static tree
2322 {
2327 }
2329 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2330 FN and whose TREE_VALUE is the binfo for the base where the
2331 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2332 DERIVED) is the base object in which FN is declared. */
2334 static tree
2336 {
2337 find_final_overrider_data ffod;
2339 /* Getting this right is a little tricky. This is valid:
2341 struct S { virtual void f (); };
2342 struct T { virtual void f (); };
2343 struct U : public S, public T { };
2345 even though calling `f' in `U' is ambiguous. But,
2347 struct R { virtual void f(); };
2348 struct S : virtual public R { virtual void f (); };
2349 struct T : virtual public R { virtual void f (); };
2350 struct U : public S, public T { };
2352 is not -- there's no way to decide whether to put `S::f' or
2353 `T::f' in the vtable for `R'.
2355 The solution is to look at all paths to BINFO. If we find
2356 different overriders along any two, then there is a problem. */
2360 /* Determine the depth of the hierarchy. */
2371 /* If there was no winner, issue an error message. */
2376 }
2378 /* Return the index of the vcall offset for FN when TYPE is used as a
2379 virtual base. */
2381 static tree
2383 {
2385 tree_pair_p p;
2393 /* There should always be an appropriate index. */
2395 }
2397 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2398 dominated by T. FN is the old function; VIRTUALS points to the
2399 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2400 of that entry in the list. */
2402 static void
2405 {
2406 tree b;
2407 tree overrider;
2408 tree delta;
2409 tree virtual_base;
2410 tree first_defn;
2416 /* Find the nearest primary base (possibly binfo itself) which defines
2417 this function; this is the class the caller will convert to when
2418 calling FN through BINFO. */
2420 {
2425 /* The nearest definition is from a lost primary. */
2428 }
2431 /* Find the final overrider. */
2434 {
2437 }
2440 /* Check for adjusting covariant return types. */
2448 /* If the overrider is invalid, don't even try. */
2450 {
2451 /* If FN is a covariant thunk, we must figure out the adjustment
2452 to the final base FN was converting to. As OVERRIDER_TARGET might
2453 also be converting to the return type of FN, we have to
2454 combine the two conversions here. */
2461 {
2465 }
2466 else
2470 /* Find the equivalent binfo within the return type of the
2471 overriding function. We will want the vbase offset from
2472 there. */
2474 over_return);
2477 {
2478 /* There was no existing virtual thunk (which takes
2479 precedence). So find the binfo of the base function's
2480 return type within the overriding function's return type.
2481 Fortunately we know the covariancy is valid (it
2482 has already been checked), so we can just iterate along
2483 the binfos, which have been chained in inheritance graph
2484 order. Of course it is lame that we have to repeat the
2485 search here anyway -- we should really be caching pieces
2486 of the vtable and avoiding this repeated work. */
2490 /* Find the base binfo within the overriding function's
2491 return type. We will always find a thunk_binfo, except
2492 when the covariancy is invalid (which we will have
2493 already diagnosed). */
2502 /* See if virtual inheritance is involved. */
2504 virtual_offset;
2511 {
2515 {
2516 /* We convert via virtual base. Adjust the fixed
2517 offset to be from there. */
2518 offset =
2522 }
2524 /* There was an existing fixed offset, this must be
2525 from the base just converted to, and the base the
2526 FN was thunking to. */
2528 else
2530 }
2531 }
2534 /* Replace the overriding function with a covariant thunk. We
2535 will emit the overriding function in its own slot as
2536 well. */
2539 }
2540 else
2544 /* If we need a covariant thunk, then we may need to adjust first_defn.
2545 The ABI specifies that the thunks emitted with a function are
2546 determined by which bases the function overrides, so we need to be
2547 sure that we're using a thunk for some overridden base; even if we
2548 know that the necessary this adjustment is zero, there may not be an
2549 appropriate zero-this-adjustment thunk for us to use since thunks for
2550 overriding virtual bases always use the vcall offset.
2552 Furthermore, just choosing any base that overrides this function isn't
2553 quite right, as this slot won't be used for calls through a type that
2554 puts a covariant thunk here. Calling the function through such a type
2555 will use a different slot, and that slot is the one that determines
2556 the thunk emitted for that base.
2558 So, keep looking until we find the base that we're really overriding
2559 in this slot: the nearest primary base that doesn't use a covariant
2560 thunk in this slot. */
2562 {
2564 /* We already know that the overrider needs a covariant thunk. */
2567 {
2574 }
2576 }
2578 /* Assume that we will produce a thunk that convert all the way to
2579 the final overrider, and not to an intermediate virtual base. */
2582 /* See if we can convert to an intermediate virtual base first, and then
2583 use the vcall offset located there to finish the conversion. */
2585 {
2586 /* If we find the final overrider, then we can stop
2587 walking. */
2592 /* If we find a virtual base, and we haven't yet found the
2593 overrider, then there is a virtual base between the
2594 declaring base (first_defn) and the final overrider. */
2596 {
2599 }
2600 }
2602 /* Compute the constant adjustment to the `this' pointer. The
2603 `this' pointer, when this function is called, will point at BINFO
2604 (or one of its primary bases, which are at the same offset). */
2606 /* The `this' pointer needs to be adjusted from the declaration to
2607 the nearest virtual base. */
2612 /* If the nearest definition is in a lost primary, we don't need an
2613 entry in our vtable. Except possibly in a constructor vtable,
2614 if we happen to get our primary back. In that case, the offset
2615 will be zero, as it will be a primary base. */
2617 else
2618 /* The `this' pointer needs to be adjusted from pointing to
2619 BINFO to pointing at the base where the final overrider
2620 appears. */
2631 else
2635 }
2637 /* Called from modify_all_vtables via dfs_walk. */
2639 static tree
2641 {
2643 tree virtuals;
2644 tree old_virtuals;
2648 /* A base without a vtable needs no modification, and its bases
2649 are uninteresting. */
2654 /* Don't do the primary vtable, if it's new. */
2658 /* There's no need to modify the vtable for a non-virtual primary
2659 base; we're not going to use that vtable anyhow. We do still
2660 need to do this for virtual primary bases, as they could become
2661 non-primary in a construction vtable. */
2666 /* Now, go through each of the virtual functions in the virtual
2667 function table for BINFO. Find the final overrider, and update
2668 the BINFO_VIRTUALS list appropriately. */
2671 virtuals;
2675 binfo,
2680 }
2682 /* Update all of the primary and secondary vtables for T. Create new
2683 vtables as required, and initialize their RTTI information. Each
2684 of the functions in VIRTUALS is declared in T and may override a
2685 virtual function from a base class; find and modify the appropriate
2686 entries to point to the overriding functions. Returns a list, in
2687 declaration order, of the virtual functions that are declared in T,
2688 but do not appear in the primary base class vtable, and which
2689 should therefore be appended to the end of the vtable for T. */
2691 static tree
2693 {
2697 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2701 /* Update all of the vtables. */
2704 /* Add virtual functions not already in our primary vtable. These
2705 will be both those introduced by this class, and those overridden
2706 from secondary bases. It does not include virtuals merely
2707 inherited from secondary bases. */
2709 {
2714 {
2715 /* We don't need to adjust the `this' pointer when
2716 calling this function. */
2720 /* This is a function not already in our vtable. Keep it. */
2722 }
2723 else
2724 /* We've already got an entry for this function. Skip it. */
2726 }
2729 }
2731 /* Get the base virtual function declarations in T that have the
2732 indicated NAME. */
2734 static void
2736 {
2739 /* Find virtual functions in T with the indicated NAME. */
2741 {
2745 {
2748 }
2749 }
2756 {
2759 }
2760 }
2762 /* If this declaration supersedes the declaration of
2763 a method declared virtual in the base class, then
2764 mark this field as being virtual as well. */
2766 void
2768 {
2771 /* In [temp.mem] we have:
2773 A specialization of a member function template does not
2774 override a virtual function from a base class. */
2781 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2782 the error_mark_node so that we know it is an overriding
2783 function. */
2784 {
2791 }
2794 {
2800 }
2805 }
2807 /* Warn about hidden virtual functions that are not overridden in t.
2808 We know that constructors and destructors don't apply. */
2810 static void
2812 {
2815 {
2823 tree base_binfo;
2824 tree binfo;
2827 /* Iterate through all of the base classes looking for possibly
2828 hidden functions. */
2831 {
2834 }
2836 /* If there are no functions to hide, continue. */
2840 /* Remove any overridden functions. */
2842 {
2846 {
2847 /* If the method from the base class has the same
2848 signature as the method from the derived class, it
2849 has been overridden. */
2854 }
2855 }
2857 /* Now give a warning for all base functions without overriders,
2858 as they are hidden. */
2859 tree base_fndecl;
2862 {
2863 /* Here we know it is a hider, and no overrider exists. */
2865 OPT_Woverloaded_virtual,
2869 }
2870 }
2871 }
2873 /* Recursive helper for finish_struct_anon. */
2875 static void
2877 {
2879 {
2880 /* We're generally only interested in entities the user
2881 declared, but we also find nested classes by noticing
2882 the TYPE_DECL that we create implicitly. You're
2883 allowed to put one anonymous union inside another,
2884 though, so we explicitly tolerate that. We use
2885 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2886 we also allow unnamed types used for defining fields. */
2895 {
2896 /* We already complained about static data members in
2897 finish_static_data_member_decl. */
2899 {
2900 auto_diagnostic_group d;
2904 "only have public non-static data members"
2907 {
2910 {
2913 "this flexibility is deprecated and will be "
2915 }
2916 }
2917 }
2918 }
2923 /* Recurse into the anonymous aggregates to correctly handle
2924 access control (c++/24926):
2926 class A {
2927 union {
2928 union {
2929 int i;
2930 };
2931 };
2932 };
2934 int j=A().i; */
2938 }
2939 }
2941 /* Check for things that are invalid. There are probably plenty of other
2942 things we should check for also. */
2944 static void
2946 {
2948 {
2957 }
2958 }
2960 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2961 will be used later during class template instantiation.
2962 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2963 a non-static member data (FIELD_DECL), a member function
2964 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2965 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2966 When FRIEND_P is nonzero, T is either a friend class
2967 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2968 (FUNCTION_DECL, TEMPLATE_DECL). */
2970 void
2972 {
2973 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2978 }
2980 /* This function is called from declare_virt_assop_and_dtor via
2981 dfs_walk_all.
2983 DATA is a type that direcly or indirectly inherits the base
2984 represented by BINFO. If BINFO contains a virtual assignment [copy
2985 assignment or move assigment] operator or a virtual constructor,
2986 declare that function in DATA if it hasn't been already declared. */
2988 static tree
2990 {
2998 /* A base without a vtable needs no modification, and its bases
2999 are uninteresting. */
3003 /* If this is a primary base, then we have already looked at the
3004 virtual functions of its vtable. */
3008 {
3012 {
3017 }
3021 }
3024 }
3026 /* If the class type T has a direct or indirect base that contains a
3027 virtual assignment operator or a virtual destructor, declare that
3028 function in T if it hasn't been already declared. */
3030 static void
3032 {
3040 dfs_declare_virt_assop_and_dtor,
3042 }
3044 /* Declare the inheriting constructor for class T inherited from base
3045 constructor CTOR with the parameter array PARMS of size NPARMS. */
3047 static void
3049 {
3052 /* We don't declare an inheriting ctor that would be a default,
3053 copy or move ctor for derived or base. */
3058 {
3062 }
3071 {
3074 }
3075 }
3077 /* Declare all the inheriting constructors for class T inherited from base
3078 constructor CTOR. */
3080 static void
3082 {
3086 {
3092 }
3097 {
3101 }
3104 {
3105 auto_diagnostic_group d;
3109 }
3110 }
3112 /* Create default constructors, assignment operators, and so forth for
3113 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3114 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3115 the class cannot have a default constructor, copy constructor
3116 taking a const reference argument, or an assignment operator taking
3117 a const reference, respectively. */
3119 static void
3123 {
3124 /* Destructor. */
3126 /* In general, we create destructors lazily. */
3135 /* [class.ctor]
3137 If there is no user-declared constructor for a class, a default
3138 constructor is implicitly declared. */
3140 {
3145 /* Don't force the declaration to get a hard answer; if the
3146 definition would have made the class non-literal, it will still be
3147 non-literal because of the base or member in question, and that
3148 gives a better diagnostic. */
3150 }
3152 /* [class.ctor]
3154 If a class definition does not explicitly declare a copy
3155 constructor, one is declared implicitly. */
3157 {
3163 }
3165 /* If there is no assignment operator, one will be created if and
3166 when it is needed. For now, just record whether or not the type
3167 of the parameter to the assignment operator will be a const or
3168 non-const reference. */
3170 {
3176 }
3178 /* We can't be lazy about declaring functions that might override
3179 a virtual function from a base class. */
3183 {
3187 {
3188 /* declare, then remove the decl */
3196 }
3197 else
3199 }
3200 }
3202 /* FIELD is a bit-field. We are finishing the processing for its
3203 enclosing type. Issue any appropriate messages and set appropriate
3204 flags. Returns false if an error has been diagnosed. */
3206 static bool
3208 {
3210 tree w;
3212 /* Extract the declared width of the bitfield, which has been
3213 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3216 /* Remove the bit-field width indicator so that the rest of the
3217 compiler does not treat that value as a qualifier. */
3220 /* Detect invalid bit-field type. */
3222 {
3225 }
3226 else
3227 {
3229 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3232 /* detect invalid field size. */
3238 {
3241 }
3243 {
3246 }
3248 {
3251 }
3261 {
3267 }
3268 }
3271 {
3275 }
3276 else
3277 {
3278 /* Non-bit-fields are aligned for their type. */
3282 }
3283 }
3285 /* FIELD is a non bit-field. We are finishing the processing for its
3286 enclosing type T. Issue any appropriate messages and set appropriate
3287 flags. */
3289 static bool
3291 tree t,
3294 {
3298 /* In C++98 an anonymous union cannot contain any fields which would change
3299 the settings of CANT_HAVE_CONST_CTOR and friends. */
3301 ;
3302 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3303 structs. So, we recurse through their fields here. */
3305 {
3310 cant_have_const_ctor,
3311 no_const_asn_ref);
3312 }
3313 /* Check members with class type for constructors, destructors,
3314 etc. */
3316 {
3317 /* Never let anything with uninheritable virtuals
3318 make it through without complaint. */
3322 {
3327 field);
3332 field);
3334 {
3338 }
3339 }
3340 else
3341 {
3354 }
3363 }
3368 /* `build_class_init_list' does not recognize
3369 non-FIELD_DECLs. */
3373 }
3375 /* Check the data members (both static and non-static), class-scoped
3376 typedefs, etc., appearing in the declaration of T. Issue
3377 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3378 declaration order) of access declarations; each TREE_VALUE in this
3379 list is a USING_DECL.
3381 In addition, set the following flags:
3383 EMPTY_P
3384 The class is empty, i.e., contains no non-static data members.
3386 CANT_HAVE_CONST_CTOR_P
3387 This class cannot have an implicitly generated copy constructor
3388 taking a const reference.
3390 CANT_HAVE_CONST_ASN_REF
3391 This class cannot have an implicitly generated assignment
3392 operator taking a const reference.
3394 All of these flags should be initialized before calling this
3395 function.
3397 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3398 fields can be added by adding to this chain. */
3400 static void
3404 {
3412 /* Assume there are no access declarations. */
3414 /* Assume this class has no pointer members. */
3416 /* Assume none of the members of this class have default
3417 initializations. */
3421 {
3429 {
3430 /* Save the access declarations for our caller. */
3433 }
3440 /* FIXME: We should fold in the checking from check_methods. */
3443 /* If we've gotten this far, it's a data member, possibly static,
3444 or an enumerator. */
3448 /* When this goes into scope, it will be a non-local reference. */
3452 {
3453 /* [class.union] (C++98)
3455 If a union contains a static data member, or a member of
3456 reference type, the program is ill-formed.
3458 In C++11 [class.union] says:
3459 If a union contains a non-static data member of reference type
3460 the program is ill-formed. */
3462 {
3466 }
3469 {
3473 }
3474 }
3476 /* Perform error checking that did not get done in
3477 grokdeclarator. */
3479 {
3483 }
3485 {
3489 }
3497 /* Now it can only be a FIELD_DECL. */
3502 /* If at least one non-static data member is non-literal, the whole
3503 class becomes non-literal. Per Core/1453, volatile non-static
3504 data members and base classes are also not allowed.
3505 Note: if the type is incomplete we will complain later on. */
3510 /* A standard-layout class is a class that:
3511 ...
3512 has the same access control (Clause 11) for all non-static data members,
3513 ... */
3520 /* If this is of reference type, check if it needs an init. */
3522 {
3528 {
3529 /* ARM $12.6.2: [A member initializer list] (or, for an
3530 aggregate, initialization by a brace-enclosed list) is the
3531 only way to initialize nonstatic const and reference
3532 members. */
3535 }
3536 }
3541 {
3543 {
3544 warning_at
3547 x);
3549 }
3553 }
3557 /* We don't treat zero-width bitfields as making a class
3558 non-empty. */
3559 ;
3560 else
3561 {
3562 /* The class is non-empty. */
3564 /* The class is not even nearly empty. */
3566 /* If one of the data members contains an empty class,
3567 so does T. */
3571 }
3573 /* This is used by -Weffc++ (see below). Warn only for pointers
3574 to members which might hold dynamic memory. So do not warn
3575 for pointers to functions or pointers to members. */
3581 {
3586 }
3592 {
3594 {
3598 }
3600 {
3604 }
3605 }
3608 /* DR 148 now allows pointers to members (which are POD themselves),
3609 to be allowed in POD structs. */
3618 /* We set DECL_C_BIT_FIELD in grokbitfield.
3619 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3624 {
3629 }
3631 /* Now that we've removed bit-field widths from DECL_INITIAL,
3632 anything left in DECL_INITIAL is an NSDMI that makes the class
3633 non-aggregate in C++11. */
3637 /* If any field is const, the structure type is pseudo-const. */
3639 {
3644 {
3645 /* ARM $12.6.2: [A member initializer list] (or, for an
3646 aggregate, initialization by a brace-enclosed list) is the
3647 only way to initialize nonstatic const and reference
3648 members. */
3651 }
3652 }
3653 /* A field that is pseudo-const makes the structure likewise. */
3655 {
3660 }
3662 /* Core issue 80: A nonstatic data member is required to have a
3663 different name from the class iff the class has a
3664 user-declared constructor. */
3669 }
3671 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3672 it should also define a copy constructor and an assignment operator to
3673 implement the correct copy semantic (deep vs shallow, etc.). As it is
3674 not feasible to check whether the constructors do allocate dynamic memory
3675 and store it within members, we approximate the warning like this:
3677 -- Warn only if there are members which are pointers
3678 -- Warn only if there is a non-trivial constructor (otherwise,
3679 there cannot be memory allocated).
3680 -- Warn only if there is a non-trivial destructor. We assume that the
3681 user at least implemented the cleanup correctly, and a destructor
3682 is needed to free dynamic memory.
3684 This seems enough for practical purposes. */
3686 && has_pointers
3690 {
3694 {
3699 }
3703 }
3705 /* Non-static data member initializers make the default constructor
3706 non-trivial. */
3708 {
3711 }
3713 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3717 /* Check anonymous struct/anonymous union fields. */
3720 /* We've built up the list of access declarations in reverse order.
3721 Fix that now. */
3723 }
3725 /* If TYPE is an empty class type, records its OFFSET in the table of
3726 OFFSETS. */
3728 static int
3730 {
3731 splay_tree_node n;
3736 /* Record the location of this empty object in OFFSETS. */
3744 type,
3748 }
3750 /* Returns nonzero if TYPE is an empty class type and there is
3751 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3753 static int
3755 {
3756 splay_tree_node n;
3757 tree t;
3762 /* Record the location of this empty object in OFFSETS. */
3772 }
3774 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3775 F for every subobject, passing it the type, offset, and table of
3776 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3777 be traversed.
3779 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3780 than MAX_OFFSET will not be walked.
3782 If F returns a nonzero value, the traversal ceases, and that value
3783 is returned. Otherwise, returns zero. */
3785 static int
3787 subobject_offset_fn f,
3788 tree offset,
3789 splay_tree offsets,
3790 tree max_offset,
3792 {
3796 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3797 stop. */
3805 {
3808 }
3811 {
3812 tree field;
3813 tree binfo;
3816 /* Avoid recursing into objects that are not interesting. */
3820 /* Record the location of TYPE. */
3825 /* Iterate through the direct base classes of TYPE. */
3829 {
3830 tree binfo_offset;
3835 tree orig_binfo;
3836 /* We cannot rely on BINFO_OFFSET being set for the base
3837 class yet, but the offsets for direct non-virtual
3838 bases can be calculated by going back to the TYPE. */
3841 offset,
3845 f,
3846 binfo_offset,
3847 offsets,
3848 max_offset,
3852 }
3855 {
3859 /* Iterate through the virtual base classes of TYPE. In G++
3860 3.2, we included virtual bases in the direct base class
3861 loop above, which results in incorrect results; the
3862 correct offsets for virtual bases are only known when
3863 working with the most derived type. */
3867 {
3869 f,
3871 offset,
3873 offsets,
3874 max_offset,
3878 }
3879 else
3880 {
3881 /* We still have to walk the primary base, if it is
3882 virtual. (If it is non-virtual, then it was walked
3883 above.) */
3889 {
3890 r = (walk_subobject_offsets
3895 }
3896 }
3897 }
3899 /* Iterate through the fields of TYPE. */
3904 {
3905 tree field_offset;
3910 f,
3912 offset,
3913 field_offset),
3914 offsets,
3915 max_offset,
3919 }
3920 }
3922 {
3925 tree index;
3927 /* Avoid recursing into objects that are not interesting. */
3930 || !domain
3934 /* Step through each of the elements in the array. */
3938 {
3940 f,
3941 offset,
3942 offsets,
3943 max_offset,
3949 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3950 there's no point in iterating through the remaining
3951 elements of the array. */
3954 }
3955 }
3958 }
3960 /* Return true iff FIELD_DECL DECL is potentially overlapping. */
3962 static bool
3964 {
3965 /* Base fields are actually potentially overlapping, but C++ bases go through
3966 a different code path based on binfos, and ObjC++ base fields are laid out
3967 in objc-act, so we don't want layout_class_type to mess with them. */
3969 {
3972 }
3976 }
3978 /* Record all of the empty subobjects of DECL_OR_BINFO. */
3980 static void
3982 splay_tree offsets)
3983 {
3988 {
3994 }
3995 else
3996 {
4001 }
4003 tree max_offset;
4004 /* If recording subobjects for a non-static data member or a
4005 non-empty base class, we do not need to record offsets beyond
4006 the size of the biggest empty class. Additional data members
4007 will go at the end of the class. Additional base classes will go
4008 either at offset zero (if empty, in which case they cannot
4009 overlap with offsets past the size of the biggest empty class) or
4010 at the end of the class.
4012 However, if we are placing an empty base class, then we must record
4013 all offsets, as either the empty class is at offset zero (where
4014 other empty classes might later be placed) or at the end of the
4015 class (where other objects might then be placed, so other empty
4016 subobjects might later overlap). */
4020 else
4024 }
4026 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4027 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4028 virtual bases of TYPE are examined. */
4030 static int
4032 tree offset,
4033 splay_tree offsets,
4035 {
4036 splay_tree_node max_node;
4038 /* Get the node in OFFSETS that indicates the maximum offset where
4039 an empty subobject is located. */
4041 /* If there aren't any empty subobjects, then there's no point in
4042 performing this check. */
4048 vbases_p);
4049 }
4051 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4052 non-static data member of the type indicated by RLI. BINFO is the
4053 binfo corresponding to the base subobject, OFFSETS maps offsets to
4054 types already located at those offsets. This function determines
4055 the position of the DECL. */
4057 static void
4059 tree decl,
4060 tree binfo,
4061 splay_tree offsets)
4062 {
4065 tree type;
4068 {
4069 /* For the purposes of determining layout conflicts, we want to
4070 use the class type of BINFO; TREE_TYPE (DECL) will be the
4071 CLASSTYPE_AS_BASE version, which does not contain entries for
4072 zero-sized bases. */
4075 }
4076 else
4077 {
4080 }
4082 /* Try to place the field. It may take more than one try if we have
4083 a hard time placing the field without putting two objects of the
4084 same type at the same address. */
4086 {
4089 /* Place this field. */
4093 /* We have to check to see whether or not there is already
4094 something of the same type at the offset we're about to use.
4095 For example, consider:
4097 struct S {};
4098 struct T : public S { int i; };
4099 struct U : public S, public T {};
4101 Here, we put S at offset zero in U. Then, we can't put T at
4102 offset zero -- its S component would be at the same address
4103 as the S we already allocated. So, we have to skip ahead.
4104 Since all data members, including those whose type is an
4105 empty class, have nonzero size, any overlap can happen only
4106 with a direct or indirect base-class -- it can't happen with
4107 a data member. */
4108 /* In a union, overlap is permitted; all members are placed at
4109 offset zero. */
4114 {
4115 /* Strip off the size allocated to this field. That puts us
4116 at the first place we could have put the field with
4117 proper alignment. */
4120 /* Bump up by the alignment required for the type. */
4121 rli->bitpos
4127 }
4130 {
4131 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4132 the offset wasn't aligned like a pointer when we started to
4133 layout this field, that affects its position. */
4136 {
4139 "alignment of %qD increased in -fabi-version=9 "
4141 else
4144 }
4146 }
4147 else
4148 /* There was no conflict. We're done laying out this field. */
4150 }
4152 /* Now that we know where it will be placed, update its
4153 BINFO_OFFSET. */
4155 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4156 this point because their BINFO_OFFSET is copied from another
4157 hierarchy. Therefore, we may not need to add the entire
4158 OFFSET. */
4164 }
4166 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4168 static int
4170 tree offset,
4172 {
4174 }
4176 /* Layout the empty base BINFO. EOC indicates the byte currently just
4177 past the end of the class, and should be correctly aligned for a
4178 class of the type indicated by BINFO; OFFSETS gives the offsets of
4179 the empty bases allocated so far. T is the most derived
4180 type. Return nonzero iff we added it at the end. */
4182 static bool
4184 splay_tree offsets)
4185 {
4186 tree alignment;
4190 tree type;
4192 {
4195 }
4196 else
4197 {
4200 }
4202 /* On some platforms (ARM), even empty classes will not be
4203 byte-aligned. */
4208 /* This routine should only be used for empty classes. */
4212 /* This is an empty base class. We first try to put it at offset
4213 zero. */
4216 offset,
4217 offsets,
4219 {
4220 /* That didn't work. Now, we move forward from the next
4221 available spot in the class. */
4225 {
4227 offset,
4228 offsets,
4230 /* We finally found a spot where there's no overlap. */
4233 /* There's overlap here, too. Bump along to the next spot. */
4235 }
4236 }
4239 {
4244 }
4247 /* Adjust BINFO_OFFSET (binfo) to be exactly OFFSET. */
4250 else
4251 {
4255 }
4258 }
4260 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4261 fields at NEXT_FIELD, and return it. */
4263 static tree
4265 {
4266 /* Create the FIELD_DECL. */
4274 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4276 else
4277 {
4280 }
4286 /* Add the new FIELD_DECL to the list of fields for T. */
4292 }
4294 /* Layout the base given by BINFO in the class indicated by RLI.
4295 *BASE_ALIGN is a running maximum of the alignments of
4296 any base class. OFFSETS gives the location of empty base
4297 subobjects. T is the most derived type. Return nonzero if the new
4298 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4299 *NEXT_FIELD, unless BINFO is for an empty base class.
4301 Returns the location at which the next field should be inserted. */
4306 {
4311 /* This error is now reported in xref_tag, thus giving better
4312 location information. */
4315 /* Place the base class. */
4317 {
4318 tree decl;
4320 /* The containing class is non-empty because it has a non-empty
4321 base class. */
4324 /* Create the FIELD_DECL. */
4327 /* Try to place the field. It may take more than one try if we
4328 have a hard time placing the field without putting two
4329 objects of the same type at the same address. */
4331 }
4332 else
4333 {
4335 /* A nearly-empty class "has no proper base class that is empty,
4336 not morally virtual, and at an offset other than zero." */
4338 {
4341 /* The check above (used in G++ 3.2) is insufficient because
4342 an empty class placed at offset zero might itself have an
4343 empty base at a nonzero offset. */
4345 empty_base_at_nonzero_offset_p,
4346 size_zero_node,
4351 }
4353 /* We used to not create a FIELD_DECL for empty base classes because of
4354 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4355 be a problem anymore. We need them to handle initialization of C++17
4356 aggregate bases. */
4358 {
4363 }
4365 /* An empty virtual base causes a class to be non-empty
4366 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4367 here because that was already done when the virtual table
4368 pointer was created. */
4369 }
4371 /* Record the offsets of BINFO and its base subobjects. */
4375 }
4377 /* Layout all of the non-virtual base classes. Record empty
4378 subobjects in OFFSETS. T is the most derived type. Return nonzero
4379 if the type cannot be nearly empty. The fields created
4380 corresponding to the base classes will be inserted at
4381 *NEXT_FIELD. */
4383 static void
4386 {
4387 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4388 subobjects. */
4393 /* The primary base class is always allocated first. */
4398 /* Now allocate the rest of the bases. */
4400 {
4401 tree base_binfo;
4405 /* The primary base was already allocated above, so we don't
4406 need to allocate it again here. */
4410 /* Virtual bases are added at the end (a primary virtual base
4411 will have already been added). */
4417 }
4418 }
4420 /* Go through the TYPE_FIELDS of T issuing any appropriate
4421 diagnostics, figuring out which methods override which other
4422 methods, and so forth. */
4424 static void
4426 {
4429 {
4435 /* The name of the field is the original field name
4436 Save this in auxiliary field for later overloading. */
4438 {
4442 }
4444 /* All user-provided destructors are non-trivial.
4445 Constructors and assignment ops are handled in
4446 grok_special_member_properties. */
4453 "%<transaction_safe_dynamic%> may only be specified for "
4455 }
4456 }
4458 /* FN is a constructor or destructor. Clone the declaration to create
4459 a specialized in-charge or not-in-charge version, as indicated by
4460 NAME. */
4462 static tree
4464 {
4465 tree parms;
4466 tree clone;
4468 /* Copy the function. */
4470 /* Reset the function name. */
4472 /* Remember where this function came from. */
4474 /* Make it easy to find the CLONE given the FN. */
4478 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4480 {
4487 }
4488 else
4489 {
4490 // Clone constraints.
4494 }
4499 /* There's no pending inline data for this function. */
4503 /* The base-class destructor is not virtual. */
4505 {
4509 }
4515 /* If there was an in-charge parameter, drop it from the function
4516 type. */
4518 {
4521 /* Skip the `this' parameter. */
4523 /* Skip the in-charge parameter. */
4525 /* And the VTT parm, in a complete [cd]tor. */
4530 {
4531 /* If we're omitting inherited parms, that just leaves the VTT. */
4534 }
4538 parmtypes);
4544 }
4546 /* Copy the function parameters. */
4548 /* Remove the in-charge parameter. */
4550 {
4554 }
4555 /* And the VTT parm, in a complete [cd]tor. */
4557 {
4560 else
4561 {
4565 }
4566 }
4568 /* A base constructor inheriting from a virtual base doesn't get the
4569 arguments. */
4574 {
4577 }
4579 /* Create the RTL for this function. */
4584 }
4586 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4587 not invoke this function directly.
4589 For a non-thunk function, returns the address of the slot for storing
4590 the function it is a clone of. Otherwise returns NULL_TREE.
4592 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4593 cloned_function is unset. This is to support the separate
4594 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4595 on a template makes sense, but not the former. */
4597 tree *
4599 {
4607 {
4608 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4611 else
4612 #endif
4614 }
4619 else
4621 }
4623 /* Produce declarations for all appropriate clones of FN. If
4624 UPDATE_METHODS is true, the clones are added to the
4625 CLASSTYPE_MEMBER_VEC. */
4627 void
4629 {
4630 tree clone;
4632 /* Avoid inappropriate cloning. */
4638 {
4639 /* For each constructor, we need two variants: an in-charge version
4640 and a not-in-charge version. */
4647 }
4648 else
4649 {
4652 /* For each destructor, we need three variants: an in-charge
4653 version, a not-in-charge version, and an in-charge deleting
4654 version. We clone the deleting version first because that
4655 means it will go second on the TYPE_FIELDS list -- and that
4656 corresponds to the correct layout order in the virtual
4657 function table.
4659 For a non-virtual destructor, we do not build a deleting
4660 destructor. */
4662 {
4666 }
4673 }
4675 /* Note that this is an abstract function that is never emitted. */
4677 }
4679 /* DECL is an in charge constructor, which is being defined. This will
4680 have had an in class declaration, from whence clones were
4681 declared. An out-of-class definition can specify additional default
4682 arguments. As it is the clones that are involved in overload
4683 resolution, we must propagate the information from the DECL to its
4684 clones. */
4686 void
4688 {
4689 tree clone;
4693 {
4700 /* Skip the 'this' parameter. */
4716 {
4718 {
4722 }
4728 {
4729 /* A default parameter has been added. Adjust the
4730 clone's parameters. */
4734 {
4737 clone_parms);
4739 }
4742 tree type
4745 clone_parms);
4753 }
4754 }
4756 }
4757 }
4759 /* For each of the constructors and destructors in T, create an
4760 in-charge and not-in-charge variant. */
4762 static void
4764 {
4765 /* While constructors can be via a using declaration, at this point
4766 we no longer need to know that. */
4772 }
4774 /* Deduce noexcept for a destructor DTOR. */
4776 void
4778 {
4781 noexcept_deferred_spec);
4782 }
4784 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4785 of TYPE for virtual functions which FNDECL overrides. Return a
4786 mask of the tm attributes found therein. */
4788 static int
4790 {
4792 tree base_binfo;
4796 {
4804 {
4808 else
4811 }
4812 else
4814 }
4817 }
4819 /* Subroutine of set_method_tm_attributes. Handle the checks and
4820 inheritance for one virtual method FNDECL. */
4822 static void
4824 {
4825 tree tm_attr;
4830 /* If FNDECL doesn't actually override anything (i.e. T is the
4831 class that first declares FNDECL virtual), then we're done. */
4838 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4839 tm_pure must match exactly, otherwise no weakening of
4840 tm_safe > tm_callable > nothing. */
4841 /* ??? The tm_pure attribute didn't make the transition to the
4842 multivendor language spec. */
4844 {
4846 {
4849 }
4850 }
4851 /* If the overridden function is tm_pure, then FNDECL must be. */
4854 /* Look for base class combinations that cannot be satisfied. */
4856 {
4862 }
4863 /* If FNDECL did not declare an attribute, then inherit the most
4864 restrictive one. */
4866 {
4868 }
4869 /* Otherwise validate that we're not weaker than a function
4870 that is being overridden. */
4871 else
4872 {
4876 }
4879 err_override:
4883 }
4885 /* For each of the methods in T, propagate a class-level tm attribute. */
4887 static void
4889 {
4892 /* Don't bother collecting tm attributes if transactional memory
4893 support is not enabled. */
4897 /* Process virtual methods first, as they inherit directly from the
4898 base virtual function and also require validation of new attributes. */
4900 {
4901 tree vchain;
4904 {
4909 }
4910 }
4912 /* If the class doesn't have an attribute, nothing more to do. */
4917 /* Any method that does not yet have a tm attribute inherits
4918 the one from the class. */
4923 }
4925 /* Returns true if FN is a default constructor. */
4927 bool
4929 {
4932 }
4934 /* Returns true iff class T has a user-provided constructor that can be called
4935 with more than zero arguments. */
4937 bool
4939 {
4944 {
4951 }
4954 }
4956 /* Returns the defaulted constructor if T has one. Otherwise, returns
4957 NULL_TREE. */
4959 tree
4961 {
4966 {
4972 }
4975 }
4977 /* Returns true iff FN is a user-provided function, i.e. user-declared
4978 and not defaulted at its first declaration. */
4980 bool
4982 {
4985 else
4989 }
4991 /* Returns true iff class T has a user-provided constructor. */
4993 bool
4995 {
5007 }
5009 /* Returns true iff class T has a user-provided or explicit constructor. */
5011 bool
5013 {
5021 {
5025 }
5028 }
5030 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5031 declared or explicitly defaulted in the class body) default
5032 constructor. */
5034 bool
5036 {
5043 {
5049 }
5052 }
5054 /* TYPE is being used as a virtual base, and has a non-trivial move
5055 assignment. Return true if this is due to there being a user-provided
5056 move assignment in TYPE or one of its subobjects; if there isn't, then
5057 multiple move assignment can't cause any harm. */
5059 bool
5061 {
5062 /* Does the type itself have a user-provided move assignment operator? */
5070 /* Do any of its bases? */
5072 tree base_binfo;
5077 /* Or non-static data members? */
5079 {
5084 }
5086 /* Seems not. */
5088 }
5090 /* If default-initialization leaves part of TYPE uninitialized, returns
5091 a DECL for the field or TYPE itself (DR 253). */
5093 tree
5095 {
5106 {
5110 }
5115 {
5119 }
5122 }
5124 /* Returns true iff for class T, a trivial synthesized default constructor
5125 would be constexpr. */
5127 bool
5129 {
5130 /* A defaulted trivial default constructor is constexpr
5131 if there is nothing to initialize. */
5134 }
5136 /* Returns true iff class T has a constexpr default constructor. */
5138 bool
5140 {
5141 tree fns;
5144 {
5145 /* The caller should have stripped an enclosing array. */
5148 }
5150 {
5153 /* Non-trivial, we need to check subobject constructors. */
5155 }
5158 }
5160 /* Returns true iff class T has a constexpr default constructor or has an
5161 implicitly declared default constructor that we can't tell if it's constexpr
5162 without forcing a lazy declaration (which might cause undesired
5163 instantiations). */
5165 bool
5167 {
5170 /* Assume it's constexpr. */
5173 }
5175 /* Returns true iff class TYPE has a virtual destructor. */
5177 bool
5179 {
5180 tree dtor;
5188 }
5190 /* Returns true iff T, a class, has a move-assignment or
5191 move-constructor. Does not lazily declare either.
5192 If USER_P is false, any move function will do. If it is true, the
5193 move function must be user-declared.
5195 Note that user-declared here is different from "user-provided",
5196 which doesn't include functions that are defaulted in the
5197 class. */
5199 bool
5201 {
5219 }
5221 /* True iff T has a move constructor that is not deleted. */
5223 bool
5225 {
5232 }
5234 /* If T, a class, has a user-provided copy constructor, copy assignment
5235 operator, or destructor, returns that function. Otherwise, null. */
5237 tree
5239 {
5242 {
5246 }
5252 {
5256 }
5259 {
5263 }
5266 }
5268 /* Nonzero if we need to build up a constructor call when initializing an
5269 object of this class, either because it has a user-declared constructor
5270 or because it doesn't have a default constructor (so we need to give an
5271 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5272 what you care about is whether or not an object can be produced by a
5273 constructor (e.g. so we don't set TREE_READONLY on const variables of
5274 such type); use this function when what you care about is whether or not
5275 to try to call a constructor to create an object. The latter case is
5276 the former plus some cases of constructors that cannot be called. */
5278 bool
5280 {
5281 tree inner;
5291 /* A user-declared constructor might be private, and a constructor might
5292 be trivial but deleted. */
5295 {
5301 }
5303 }
5305 /* Like type_build_ctor_call, but for destructors. */
5307 bool
5309 {
5310 tree inner;
5319 /* A user-declared destructor might be private, and a destructor might
5320 be trivial but deleted. */
5323 {
5329 }
5331 }
5333 /* Remove all zero-width bit-fields from T. */
5335 static void
5337 {
5342 {
5345 /* We should not be confused by the fact that grokbitfield
5346 temporarily sets the width of the bit field into
5347 DECL_BIT_FIELD_REPRESENTATIVE (*fieldsp).
5348 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5349 to that width. */
5353 else
5355 }
5356 }
5358 /* Returns TRUE iff we need a cookie when dynamically allocating an
5359 array whose elements have the indicated class TYPE. */
5361 static bool
5363 {
5364 tree fns;
5369 /* If there's a non-trivial destructor, we need a cookie. In order
5370 to iterate through the array calling the destructor for each
5371 element, we'll have to know how many elements there are. */
5375 /* If the usual deallocation function is a two-argument whose second
5376 argument is of type `size_t', then we have to pass the size of
5377 the array to the deallocation function, so we will need to store
5378 a cookie. */
5382 /* If there are no `operator []' members, or the lookup is
5383 ambiguous, then we don't need a cookie. */
5386 /* Loop through all of the functions. */
5388 {
5391 /* See if this function is a one-argument delete function. If
5392 it is, then it will be the usual deallocation function. */
5396 /* Do not consider this function if its second argument is an
5397 ellipsis. */
5400 /* Otherwise, if we have a two-argument function and the second
5401 argument is `size_t', it will be the usual deallocation
5402 function -- unless there is one-argument function, too. */
5406 }
5409 }
5411 /* Finish computing the `literal type' property of class type T.
5413 At this point, we have already processed base classes and
5414 non-static data members. We need to check whether the copy
5415 constructor is trivial, the destructor is trivial, and there
5416 is a trivial default constructor or at least one constexpr
5417 constructor other than the copy constructor. */
5419 static void
5421 {
5422 tree fn;
5434 /* C++14 DR 1684 removed this restriction. */
5442 {
5445 {
5446 auto_diagnostic_group d;
5448 "enclosing class of %<constexpr%> non-static "
5451 }
5452 }
5453 }
5455 /* T is a non-literal type used in a context which requires a constant
5456 expression. Explain why it isn't literal. */
5458 void
5460 {
5470 /* Already explained. */
5473 auto_diagnostic_group d;
5477 " %qT is a closure type, which is only literal in "
5485 {
5487 " %q+T is not an aggregate, does not have a trivial "
5488 "default constructor, and has no %<constexpr%> constructor that "
5491 /* Note that we can't simply call locate_ctor because when the
5492 constructor is deleted it just returns NULL_TREE. */
5494 {
5501 {
5504 else
5507 }
5508 }
5509 }
5510 else
5511 {
5515 {
5518 {
5524 }
5525 }
5527 {
5528 tree ftype;
5533 {
5536 field);
5539 }
5543 }
5544 }
5545 }
5547 /* Check the validity of the bases and members declared in T. Add any
5548 implicitly-generated functions (like copy-constructors and
5549 assignment operators). Compute various flag bits (like
5550 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5551 level: i.e., independently of the ABI in use. */
5553 static void
5555 {
5556 /* Nonzero if the implicitly generated copy constructor should take
5557 a non-const reference argument. */
5559 /* Nonzero if the implicitly generated assignment operator
5560 should take a non-const reference argument. */
5562 tree access_decls;
5565 tree fn;
5567 /* By default, we use const reference arguments and generate default
5568 constructors. */
5572 /* Check all the base-classes and set FMEM members to point to arrays
5573 of potential interest. */
5576 /* Deduce noexcept on destructor. This needs to happen after we've set
5577 triviality flags appropriately for our bases. */
5582 /* Check all the method declarations. */
5585 /* Save the initial values of these flags which only indicate whether
5586 or not the class has user-provided functions. As we analyze the
5587 bases and members we can set these flags for other reasons. */
5591 /* Check all the data member declarations. We cannot call
5592 check_field_decls until we have called check_bases check_methods,
5593 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5594 being set appropriately. */
5599 /* A nearly-empty class has to be vptr-containing; a nearly empty
5600 class contains just a vptr. */
5604 /* Do some bookkeeping that will guide the generation of implicitly
5605 declared member functions. */
5608 /* We need to call a constructor for this class if it has a
5609 user-provided constructor, or if the default constructor is going
5610 to initialize the vptr. (This is not an if-and-only-if;
5611 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5612 themselves need constructing.) */
5615 /* [dcl.init.aggr]
5617 An aggregate is an array or a class with no user-provided
5618 constructors ... and no virtual functions.
5620 Again, other conditions for being an aggregate are checked
5621 elsewhere. */
5627 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5628 retain the old definition internally for ABI reasons. */
5637 /* If the only explicitly declared default constructor is user-provided,
5638 set TYPE_HAS_COMPLEX_DFLT. */
5644 /* Warn if a public base of a polymorphic type has an accessible
5645 non-virtual destructor. It is only now that we know the class is
5646 polymorphic. Although a polymorphic base will have a already
5647 been diagnosed during its definition, we warn on use too. */
5649 {
5652 tree base_binfo;
5656 {
5664 basetype);
5665 }
5666 }
5668 /* If the class has no user-declared constructor, but does have
5669 non-static const or reference data members that can never be
5670 initialized, issue a warning. */
5672 /* Classes with user-declared constructors are presumed to
5673 initialize these members. */
5675 /* Aggregates can be initialized with brace-enclosed
5676 initializers. */
5678 {
5679 tree field;
5682 {
5683 tree type;
5700 }
5701 }
5703 /* Synthesize any needed methods. */
5705 cant_have_const_ctor,
5706 no_const_asn_ref);
5708 /* Check defaulted declarations here so we have cant_have_const_ctor
5709 and don't need to worry about clones. */
5714 {
5717 {
5718 bool imp_const_p
5724 /* If the function is defaulted outside the class, we just
5725 give the synthesis error. Core Issue #1331 says this is
5726 no longer ill-formed, it is defined as deleted instead. */
5728 }
5730 }
5733 {
5734 /* "This class type is not an aggregate." */
5736 }
5738 /* Compute the 'literal type' property before we
5739 do anything with non-static member functions. */
5742 /* Create the in-charge and not-in-charge variants of constructors
5743 and destructors. */
5746 /* Process the using-declarations. */
5750 /* Figure out whether or not we will need a cookie when dynamically
5751 allocating an array of this type. */
5754 }
5756 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5757 accordingly. If a new vfield was created (because T doesn't have a
5758 primary base class), then the newly created field is returned. It
5759 is not added to the TYPE_FIELDS list; it is the caller's
5760 responsibility to do that. Accumulate declared virtual functions
5761 on VIRTUALS_P. */
5763 static tree
5765 {
5766 tree fn;
5768 /* Collect the virtual functions declared in T. */
5773 {
5782 }
5784 /* If we couldn't find an appropriate base class, create a new field
5785 here. Even if there weren't any new virtual functions, we might need a
5786 new virtual function table if we're supposed to include vptrs in
5787 all classes that need them. */
5789 {
5790 /* We build this decl with vtbl_ptr_type_node, which is a
5791 `vtable_entry_type*'. It might seem more precise to use
5792 `vtable_entry_type (*)[N]' where N is the number of virtual
5793 functions. However, that would require the vtable pointer in
5794 base classes to have a different type than the vtable pointer
5795 in derived classes. We could make that happen, but that
5796 still wouldn't solve all the problems. In particular, the
5797 type-based alias analysis code would decide that assignments
5798 to the base class vtable pointer can't alias assignments to
5799 the derived class vtable pointer, since they have different
5800 types. Thus, in a derived class destructor, where the base
5801 class constructor was inlined, we could generate bad code for
5802 setting up the vtable pointer.
5804 Therefore, we use one type for all vtable pointers. We still
5805 use a type-correct type; it's just doesn't indicate the array
5806 bounds. That's better than using `void*' or some such; it's
5807 cleaner, and it let's the alias analysis code know that these
5808 stores cannot alias stores to void*! */
5809 tree field;
5822 /* This class is non-empty. */
5826 }
5829 }
5831 /* Add OFFSET to all base types of BINFO which is a base in the
5832 hierarchy dominated by T.
5834 OFFSET, which is a type offset, is number of bytes. */
5836 static void
5838 {
5840 tree primary_binfo;
5841 tree base_binfo;
5843 /* Update BINFO's offset. */
5848 offset));
5850 /* Find the primary base class. */
5856 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5857 downwards. */
5859 {
5860 /* Don't do the primary base twice. */
5868 }
5869 }
5871 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5872 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5873 empty subobjects of T. */
5875 static void
5877 {
5878 tree vbase;
5885 /* Find the last field. The artificial fields created for virtual
5886 bases will go after the last extant field to date. */
5891 /* Go through the virtual bases, allocating space for each virtual
5892 base that is not already a primary base class. These are
5893 allocated in inheritance graph order. */
5895 {
5900 {
5901 /* This virtual base is not a primary base of any class in the
5902 hierarchy, so we have to add space for it. */
5905 }
5906 }
5907 }
5909 /* Returns the offset of the byte just past the end of the base class
5910 BINFO. */
5912 static tree
5914 {
5915 tree size;
5920 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5921 allocate some space for it. It cannot have virtual bases, so
5922 TYPE_SIZE_UNIT is fine. */
5924 else
5928 }
5930 /* Returns the offset of the byte just past the end of the base class
5931 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
5932 only non-virtual bases are included. If INCLUDE_FIELDS_P is true,
5933 then also consider non-static data members. */
5935 static tree
5937 {
5940 tree binfo;
5941 tree base_binfo;
5942 tree offset;
5947 {
5957 }
5962 {
5967 }
5972 {
5976 }
5979 }
5981 /* Warn about bases of T that are inaccessible because they are
5982 ambiguous. For example:
5984 struct S {};
5985 struct T : public S {};
5986 struct U : public S, public T {};
5988 Here, `(S*) new U' is not allowed because there are two `S'
5989 subobjects of U. */
5991 static void
5993 {
5996 tree basetype;
5997 tree binfo;
5998 tree base_binfo;
6000 /* If there are no repeated bases, nothing can be ambiguous. */
6004 /* Check direct bases. */
6007 {
6013 }
6015 /* Check for ambiguous virtual bases. */
6019 {
6025 }
6026 }
6028 /* Compare two INTEGER_CSTs K1 and K2. */
6030 static int
6032 {
6034 }
6036 /* Increase the size indicated in RLI to account for empty classes
6037 that are "off the end" of the class. */
6039 static void
6041 {
6042 tree eoc;
6043 tree rli_size;
6045 /* It might be the case that we grew the class to allocate a
6046 zero-sized base class. That won't be reflected in RLI, yet,
6047 because we are willing to overlay multiple bases at the same
6048 offset. However, now we need to make sure that RLI is big enough
6049 to reflect the entire class. */
6054 {
6055 /* The size should have been rounded to a whole byte. */
6058 rli->bitpos
6067 }
6068 }
6070 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
6071 BINFO_OFFSETs for all of the base-classes. Position the vtable
6072 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
6074 static void
6076 {
6077 tree non_static_data_members;
6078 tree field;
6079 tree vptr;
6080 record_layout_info rli;
6081 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6082 types that appear at that offset. */
6083 splay_tree empty_base_offsets;
6084 /* True if the last field laid out was a bit-field. */
6086 /* The location at which the next field should be inserted. */
6089 /* Keep track of the first non-static data member. */
6092 /* Start laying out the record. */
6095 /* Mark all the primary bases in the hierarchy. */
6098 /* Create a pointer to our virtual function table. */
6101 /* The vptr is always the first thing in the class. */
6103 {
6108 }
6109 else
6112 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6117 /* Layout the non-static data members. */
6119 {
6120 tree type;
6121 tree padding;
6123 /* We still pass things that aren't non-static data members to
6124 the back end, in case it wants to do something with them. */
6126 {
6128 /* If the static data member has incomplete type, keep track
6129 of it so that it can be completed later. (The handling
6130 of pending statics in finish_record_layout is
6131 insufficient; consider:
6133 struct S1;
6134 struct S2 { static S1 s1; };
6136 At this point, finish_record_layout will be called, but
6137 S1 is still incomplete.) */
6139 {
6141 /* The visibility of static data members is determined
6142 at their point of declaration, not their point of
6143 definition. */
6145 }
6147 }
6159 {
6160 /* if D is a potentially-overlapping data member, update sizeof(C) to
6161 max (sizeof(C), offset(D)+max (nvsize(D), dsize(D))). */
6165 {
6168 }
6169 else
6170 {
6173 }
6174 }
6176 /* If this field is a bit-field whose width is greater than its
6177 type, then there are some special rules for allocating
6178 it. */
6181 {
6183 /* We must allocate the bits as if suitably aligned for the
6184 longest integer type that fits in this many bits. Then,
6185 we are supposed to use the left over bits as additional
6186 padding. */
6188 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6196 {
6198 /* Too big, so our current guess is what we want. */
6200 /* Not bigger than limit, ok */
6202 }
6204 /* Figure out how much additional padding is required. */
6206 /* In a union, the padding field must have the full width
6207 of the bit-field; all fields start at offset zero. */
6209 else
6216 /* An unnamed bitfield does not normally affect the
6217 alignment of the containing class on a target where
6218 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6219 make any exceptions for unnamed bitfields when the
6220 bitfields are longer than their types. Therefore, we
6221 temporarily give the field a name. */
6223 {
6226 }
6232 empty_base_offsets);
6235 /* Now that layout has been performed, set the size of the
6236 field to the size of its declared type; the rest of the
6237 field is effectively invisible. */
6239 /* We must also reset the DECL_MODE of the field. */
6241 }
6244 else
6246 empty_base_offsets);
6248 /* Remember the location of any empty classes in FIELD. */
6251 /* If a bit-field does not immediately follow another bit-field,
6252 and yet it starts in the middle of a byte, we have failed to
6253 comply with the ABI. */
6256 /* The TREE_NO_WARNING flag gets set by Objective-C when
6257 laying out an Objective-C class. The ObjC ABI differs
6258 from the C++ ABI, and so we do not want a warning
6259 here. */
6261 && !last_field_was_bitfield
6264 bitsize_unit_node)))
6266 "offset of %qD is not ABI-compliant and may "
6269 /* The middle end uses the type of expressions to determine the
6270 possible range of expression values. In order to optimize
6271 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6272 must be made aware of the width of "i", via its type.
6274 Because C++ does not have integer types of arbitrary width,
6275 we must (for the purposes of the front end) convert from the
6276 type assigned here to the declared type of the bitfield
6277 whenever a bitfield expression is used as an rvalue.
6278 Similarly, when assigning a value to a bitfield, the value
6279 must be converted to the type given the bitfield here. */
6281 {
6286 {
6293 }
6294 }
6296 /* If we needed additional padding after this field, add it
6297 now. */
6299 {
6300 tree padding_field;
6303 FIELD_DECL,
6304 NULL_TREE,
6305 char_type_node);
6313 NULL_TREE,
6314 empty_base_offsets);
6315 }
6318 }
6321 {
6322 /* Make sure that we are on a byte boundary so that the size of
6323 the class without virtual bases will always be a round number
6324 of bytes. */
6327 }
6329 /* Delete all zero-width bit-fields from the list of fields. Now
6330 that the type is laid out they are no longer important. */
6334 {
6335 /* T needs a different layout as a base (eliding virtual bases
6336 or whatever). Create that version. */
6339 /* If the ABI version is not at least two, and the last
6340 field was a bit-field, RLI may not be on a byte
6341 boundary. In particular, rli_size_unit_so_far might
6342 indicate the last complete byte, while rli_size_so_far
6343 indicates the total number of bits used. Therefore,
6344 rli_size_so_far, rather than rli_size_unit_so_far, is
6345 used to compute TYPE_SIZE_UNIT. */
6353 eoc);
6364 /* Copy the non-static data members of T. This will include its
6365 direct non-virtual bases & vtable. */
6369 {
6373 }
6376 /* We use the base type for trivial assignments, and hence it
6377 needs a mode. */
6382 /* Record the base version of the type. */
6384 }
6385 else
6388 /* Every empty class contains an empty class. */
6392 /* Set the TYPE_DECL for this type to contain the right
6393 value for DECL_OFFSET, so that we can use it as part
6394 of a COMPONENT_REF for multiple inheritance. */
6397 /* Now fix up any virtual base class types that we left lying
6398 around. We must get these done before we try to lay out the
6399 virtual function table. As a side-effect, this will remove the
6400 base subobject fields. */
6403 /* Make sure that empty classes are reflected in RLI at this
6404 point. */
6407 /* Make sure not to create any structures with zero size. */
6413 /* If this is a non-POD, declaring it packed makes a difference to how it
6414 can be used as a field; don't let finalize_record_size undo it. */
6418 /* Let the back end lay out the type. */
6427 /* Warn about bases that can't be talked about due to ambiguity. */
6430 /* Now that we're done with layout, give the base fields the real types. */
6435 /* Clean up. */
6442 }
6444 /* Determine the "key method" for the class type indicated by TYPE,
6445 and set CLASSTYPE_KEY_METHOD accordingly. */
6447 void
6449 {
6450 tree method;
6457 /* The key method is the first non-pure virtual function that is not
6458 inline at the point of class definition. On some targets the
6459 key function may not be inline; those targets should not call
6460 this function until the end of the translation unit. */
6466 {
6469 }
6472 }
6474 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6475 class data member of non-zero size, otherwise false. */
6479 {
6487 {
6491 }
6494 }
6496 /* Used by find_flexarrays and related functions. */
6498 struct flexmems_t
6499 {
6500 /* The first flexible array member or non-zero array member found
6501 in the order of layout. */
6502 tree array;
6503 /* First non-static non-empty data member in the class or its bases. */
6504 tree first;
6505 /* The first non-static non-empty data member following either
6506 the flexible array member, if found, or the zero-length array member
6507 otherwise. AFTER[1] refers to the first such data member of a union
6508 of which the struct containing the flexible array member or zero-length
6509 array is a member, or NULL when no such union exists. This element is
6510 only used during searching, not for diagnosing problems. AFTER[0]
6511 refers to the first such data member that is not a member of such
6512 a union. */
6515 /* Refers to a struct (not union) in which the struct of which the flexible
6516 array is member is defined. Used to diagnose strictly (according to C)
6517 invalid uses of the latter structs. */
6518 tree enclosing;
6519 };
6521 /* Find either the first flexible array member or the first zero-length
6522 array, in that order of preference, among members of class T (but not
6523 its base classes), and set members of FMEM accordingly.
6524 BASE_P is true if T is a base class of another class.
6525 PUN is set to the outermost union in which the flexible array member
6526 (or zero-length array) is defined if one such union exists, otherwise
6527 to NULL.
6528 Similarly, PSTR is set to a data member of the outermost struct of
6529 which the flexible array is a member if one such struct exists,
6530 otherwise to NULL. */
6532 static void
6536 {
6537 /* Set the "pointer" to the outermost enclosing union if not set
6538 yet and maintain it for the remainder of the recursion. */
6543 {
6547 /* Is FLD a typedef for an anonymous struct? */
6549 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6550 handled elsewhere so that errors like the following are detected
6551 as well:
6552 typedef struct { int i, a[], j; } S; // bug c++/72753
6553 S s [2]; // bug c++/68489
6554 */
6559 {
6560 /* Check the nested unnamed type referenced via a typedef
6561 independently of FMEM (since it's not a data member of
6562 the enclosing class). */
6565 }
6567 /* Skip anything that's GCC-generated or not a (non-static) data
6568 member. */
6572 /* Type of the member. */
6577 /* Determine the type of the array element or object referenced
6578 by the member so that it can be checked for flexible array
6579 members if it hasn't been yet. */
6586 {
6588 {
6589 /* Once the member after the flexible array has been found
6590 we're done. */
6593 }
6596 {
6597 /* Descend into the non-static member struct or union and try
6598 to find a flexible array member or zero-length array among
6599 its members. This is only necessary for anonymous types
6600 and types in whose context the current type T has not been
6601 defined (the latter must not be checked again because they
6602 are already in the process of being checked by one of the
6603 recursive calls). */
6608 /* If this member isn't anonymous and a prior non-flexible array
6609 member has been seen in one of the enclosing structs, clear
6610 the FIRST member since it doesn't contribute to the flexible
6611 array struct's members. */
6622 {
6623 /* Restore the FIRST member reset above if no flexible
6624 array member has been found in this member's struct. */
6626 }
6628 /* If the member struct contains the first flexible array
6629 member, or if this member is a base class, continue to
6630 the next member and avoid setting the FMEM->NEXT pointer
6631 to point to it. */
6634 }
6635 }
6638 {
6639 /* Remember the first non-static data member. */
6643 /* Remember the first non-static data member after the flexible
6644 array member, if one has been found, or the zero-length array
6645 if it has been found. */
6648 }
6650 /* Skip non-arrays. */
6654 /* Determine the upper bound of the array if it has one. */
6656 {
6658 {
6659 /* Make a record of the zero-length array if either one
6660 such field or a flexible array member has been seen to
6661 handle the pathological and unlikely case of multiple
6662 such members. */
6665 }
6667 {
6668 /* Remember the first zero-length array unless a flexible array
6669 member has already been seen. */
6672 }
6673 }
6674 else
6675 {
6676 /* Flexible array members have no upper bound. */
6678 {
6680 {
6681 /* Replace the zero-length array if it's been stored and
6682 reset the after pointer. */
6686 }
6688 /* Make a record of another flexible array member. */
6690 }
6691 else
6692 {
6695 }
6696 }
6697 }
6698 }
6700 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6701 a flexible array member (or the zero-length array extension). */
6703 static void
6705 {
6707 {
6708 auto_diagnostic_group d;
6719 }
6720 }
6722 /* Issue diagnostics for invalid flexible array members or zero-length
6723 arrays that are not the last elements of the containing class or its
6724 base classes or that are its sole members. */
6726 static void
6728 {
6733 {
6736 }
6738 /* Has a diagnostic been issued? */
6744 {
6751 {
6754 auto_diagnostic_group d;
6756 {
6759 }
6760 }
6761 }
6762 else
6763 {
6770 {
6774 auto_diagnostic_group d;
6777 /* In the unlikely event that the member following the flexible
6778 array member is declared in a different class, or the member
6779 overlaps another member of a common union, point to it.
6780 Otherwise it should be obvious. */
6784 {
6789 }
6790 }
6791 }
6795 }
6798 /* Recursively check to make sure that any flexible array or zero-length
6799 array members of class T or its bases are valid (i.e., not the sole
6800 non-static data member of T and, if one exists, that it is the last
6801 non-static data member of T and its base classes. FMEM is expected
6802 to be initially null and is used internally by recursive calls to
6803 the function. Issue the appropriate diagnostics for the array member
6804 that fails the checks. */
6806 static void
6809 {
6810 /* Initialize the result of a search for flexible array and zero-length
6811 array members. Avoid doing any work if the most interesting FMEM data
6812 have already been populated. */
6821 /* Recursively check the primary base class first. */
6823 {
6826 }
6828 /* Recursively check the base classes. */
6831 {
6834 /* The primary base class was already checked above. */
6838 /* Virtual base classes are at the end. */
6842 /* Check the base class. */
6844 }
6847 {
6848 /* Check virtual base classes only once per derived class.
6849 I.e., this check is not performed recursively for base
6850 classes. */
6852 tree base_binfo;
6856 {
6857 /* Check the virtual base class. */
6861 }
6862 }
6864 /* Is the type unnamed (and therefore a member of it potentially
6865 an anonymous struct or union)? */
6868 /* Search the members of the current (possibly derived) class, skipping
6869 unnamed structs and unions since those could be anonymous. */
6874 {
6875 /* Issue diagnostics for invalid flexible and zero-length array
6876 members found in base classes or among the members of the current
6877 class. Ignore anonymous structs and unions whose members are
6878 considered to be members of the enclosing class and thus will
6879 be diagnosed when checking it. */
6881 }
6882 }
6884 /* Perform processing required when the definition of T (a class type)
6885 is complete. Diagnose invalid definitions of flexible array members
6886 and zero-size arrays. */
6888 void
6890 {
6891 tree x;
6892 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6896 {
6901 }
6903 /* If this type was previously laid out as a forward reference,
6904 make sure we lay it out again. */
6908 /* Make assumptions about the class; we'll reset the flags if
6909 necessary. */
6915 /* Do end-of-class semantic processing: checking the validity of the
6916 bases and members and add implicitly generated methods. */
6919 /* Find the key method. */
6921 {
6922 /* The Itanium C++ ABI permits the key method to be chosen when
6923 the class is defined -- even though the key method so
6924 selected may later turn out to be an inline function. On
6925 some systems (such as ARM Symbian OS) the key method cannot
6926 be determined until the end of the translation unit. On such
6927 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6928 will cause the class to be added to KEYED_CLASSES. Then, in
6929 finish_file we will determine the key method. */
6933 /* If a polymorphic class has no key method, we may emit the vtable
6934 in every translation unit where the class definition appears. If
6935 we're devirtualizing, we can look into the vtable even if we
6936 aren't emitting it. */
6939 }
6941 /* Layout the class itself. */
6943 /* COMPLETE_TYPE_P is now true. */
6947 /* With the layout complete, check for flexible array members and
6948 zero-length arrays that might overlap other members in the final
6949 layout. */
6954 /* If necessary, create the primary vtable for this class. */
6956 {
6957 /* We must enter these virtuals into the table. */
6961 /* Here we know enough to change the type of our virtual
6962 function table, but we will wait until later this function. */
6965 /* If we're warning about ABI tags, check the types of the new
6966 virtual functions. */
6970 }
6973 {
6975 tree fn;
6982 /* Add entries for virtual functions introduced by this class. */
6986 /* Set DECL_VINDEX for all functions declared in this class. */
6988 fn;
6990 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6992 {
6996 /* A thunk. We should never be calling this entry directly
6997 from this vtable -- we'd use the entry for the non
6998 thunk base function. */
7002 }
7003 }
7011 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
7012 for any static member objects of the type we're working on. */
7021 /* Complain if one of the field types requires lower visibility. */
7024 /* Make the rtl for any new vtables we have created, and unmark
7025 the base types we marked. */
7028 /* Build the VTT for T. */
7035 "%q#T has virtual functions and accessible"
7043 /* Class layout, assignment of virtual table slots, etc., is now
7044 complete. Give the back end a chance to tweak the visibility of
7045 the class or perform any other required target modifications. */
7055 /* Finish debugging output for this type. */
7059 {
7062 {
7065 }
7067 {
7070 else
7071 {
7074 }
7076 }
7078 {
7080 "the type of the first field has a different ABI from the "
7083 }
7084 }
7085 }
7087 /* When T was built up, the member declarations were added in reverse
7088 order. Rearrange them to declaration order. */
7090 void
7092 {
7093 tree next;
7094 tree prev;
7095 tree x;
7097 /* The following lists are all in reverse order. Put them in
7098 declaration order now. */
7101 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
7102 order, so we can't just use nreverse. Due to stat_hack
7103 chicanery in finish_member_declaration. */
7108 {
7112 }
7115 {
7118 }
7119 }
7121 tree
7123 {
7126 /* Now that we've got all the field declarations, reverse everything
7127 as necessary. */
7133 /* Nadger the current location so that diagnostics point to the start of
7134 the struct, not the end. */
7138 {
7139 tree x;
7141 /* We need to add the target functions of USING_DECLS, so that
7142 they can be found when the using declaration is not
7143 instantiated yet. */
7146 {
7151 }
7157 /* COMPLETE_TYPE_P is now true. */
7161 /* We need to emit an error message if this type was used as a parameter
7162 and it is an abstract type, even if it is a template. We construct
7163 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7164 account and we call complete_vars with this type, which will check
7165 the PARM_DECLS. Note that while the type is being defined,
7166 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7167 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7174 /* Remember current #pragma pack value. */
7177 /* Fix up any variants we've already built. */
7179 {
7183 }
7184 }
7185 else
7187 /* COMPLETE_TYPE_P is now true. */
7192 {
7193 /* People keep complaining that the compiler crashes on an invalid
7194 definition of initializer_list, so I guess we should explicitly
7195 reject it. What the compiler internals care about is that it's a
7196 template and has a pointer field followed by size_type field. */
7199 {
7202 {
7206 }
7207 }
7211 }
7219 else
7223 /* Lambdas are defined by the LAMBDA_EXPR. */
7228 }
7229 \f
7230 /* Hash table to avoid endless recursion when handling references. */
7233 /* Return the dynamic type of INSTANCE, if known.
7234 Used to determine whether the virtual function table is needed
7235 or not.
7237 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7238 of our knowledge of its type. *NONNULL should be initialized
7239 before this function is called. */
7241 static tree
7243 {
7244 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7247 {
7251 else
7255 /* This is a call to a constructor, hence it's never zero. */
7258 {
7262 }
7266 /* This is a call to a constructor, hence it's never zero. */
7268 {
7272 }
7281 /* Propagate nonnull. */
7286 CASE_CONVERT:
7292 {
7293 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7294 with a real object -- given &p->f, p can still be null. */
7296 /* ??? Probably should check DECL_WEAK here. */
7299 }
7303 /* If this component is really a base class reference, then the field
7304 itself isn't definitive. */
7313 {
7317 }
7318 /* fall through. */
7323 {
7327 }
7329 {
7333 /* if we're in a ctor or dtor, we know our type. If
7334 current_class_ptr is set but we aren't in a function, we're in
7335 an NSDMI (and therefore a constructor). */
7340 {
7344 }
7345 }
7347 {
7348 /* We only need one hash table because it is always left empty. */
7350 fixed_type_or_null_ref_ht
7353 /* Reference variables should be references to objects. */
7357 /* Enter the INSTANCE in a table to prevent recursion; a
7358 variable's initializer may refer to the variable
7359 itself. */
7364 {
7365 tree type;
7374 }
7375 }
7380 }
7381 #undef RECUR
7382 }
7384 /* Return nonzero if the dynamic type of INSTANCE is known, and
7385 equivalent to the static type. We also handle the case where
7386 INSTANCE is really a pointer. Return negative if this is a
7387 ctor/dtor. There the dynamic type is known, but this might not be
7388 the most derived base of the original object, and hence virtual
7389 bases may not be laid out according to this type.
7391 Used to determine whether the virtual function table is needed
7392 or not.
7394 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7395 of our knowledge of its type. *NONNULL should be initialized
7396 before this function is called. */
7398 int
7400 {
7403 tree fixed;
7405 /* processing_template_decl can be false in a template if we're in
7406 instantiate_non_dependent_expr, but we still want to suppress
7407 this check. */
7409 {
7410 /* In a template we only care about the type of the result. */
7414 }
7424 }
7426 \f
7427 void
7429 {
7432 current_class_stack
7440 }
7442 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7444 static void
7446 {
7447 tree type;
7449 /* We are re-entering the same class we just left, so we don't
7450 have to search the whole inheritance matrix to find all the
7451 decls to bind again. Instead, we install the cached
7452 class_shadowed list and walk through it binding names. */
7455 /* Restore IDENTIFIER_TYPE_VALUE. */
7457 type;
7460 }
7462 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7463 appropriate for TYPE.
7465 So that we may avoid calls to lookup_name, we cache the _TYPE
7466 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7468 For multiple inheritance, we perform a two-pass depth-first search
7469 of the type lattice. */
7471 void
7473 {
7474 class_stack_node_t csn;
7478 /* Make sure there is enough room for the new entry on the stack. */
7480 {
7482 current_class_stack
7484 current_class_stack_size);
7485 }
7487 /* Insert a new entry on the class stack. */
7494 current_class_depth++;
7496 /* Now set up the new type. */
7502 /* By default, things in classes are private, while things in
7503 structures or unions are public. */
7505 ? access_private_node
7511 {
7512 /* Forcibly remove any old class remnants. */
7514 }
7520 else
7522 }
7524 /* When we exit a toplevel class scope, we save its binding level so
7525 that we can restore it quickly. Here, we've entered some other
7526 class, so we must invalidate our cache. */
7528 void
7530 {
7532 }
7534 /* Get out of the current class scope. If we were in a class scope
7535 previously, that is the one popped to. */
7537 void
7539 {
7542 current_class_depth--;
7548 }
7550 /* Mark the top of the class stack as hidden. */
7552 void
7554 {
7557 }
7559 /* Mark the top of the class stack as un-hidden. */
7561 void
7563 {
7566 }
7568 /* If the class type currently being defined is either T or
7569 a nested type of T, returns the type from the current_class_stack,
7570 which might be equivalent to but not equal to T in case of
7571 constrained partial specializations. */
7573 tree
7575 {
7583 /* We start looking from 1 because entry 0 is from global scope,
7584 and has no type. */
7586 {
7587 tree c;
7590 else
7591 {
7595 }
7600 }
7602 }
7604 /* If either current_class_type or one of its enclosing classes are derived
7605 from T, return the appropriate type. Used to determine how we found
7606 something via unqualified lookup. */
7608 tree
7610 {
7613 /* The bases of a dependent type are unknown. */
7624 {
7629 }
7632 }
7634 /* Return the outermost enclosing class type that is still open, or
7635 NULL_TREE. */
7637 tree
7639 {
7646 {
7653 }
7655 }
7657 /* Returns the innermost class type which is not a lambda closure type. */
7659 tree
7661 {
7666 }
7668 /* When entering a class scope, all enclosing class scopes' names with
7669 static meaning (static variables, static functions, types and
7670 enumerators) have to be visible. This recursive function calls
7671 pushclass for all enclosing class contexts until global or a local
7672 scope is reached. TYPE is the enclosed class. */
7674 void
7676 {
7677 /* A namespace might be passed in error cases, like A::B:C. */
7685 }
7687 /* Undoes a push_nested_class call. */
7689 void
7691 {
7697 }
7699 /* Returns the number of extern "LANG" blocks we are nested within. */
7701 int
7703 {
7705 }
7707 /* Set global variables CURRENT_LANG_NAME to appropriate value
7708 so that behavior of name-mangling machinery is correct. */
7710 void
7712 {
7719 else
7721 }
7723 /* Get out of the current language scope. */
7725 void
7727 {
7729 }
7730 \f
7731 /* Type instantiation routines. */
7733 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7734 matches the TARGET_TYPE. If there is no satisfactory match, return
7735 error_mark_node, and issue an error & warning messages under
7736 control of FLAGS. Permit pointers to member function if FLAGS
7737 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7738 a template-id, and EXPLICIT_TARGS are the explicitly provided
7739 template arguments.
7741 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7742 is the base path used to reference those member functions. If
7743 the address is resolved to a member function, access checks will be
7744 performed and errors issued if appropriate. */
7746 static tree
7748 tree overload,
7749 tsubst_flags_t complain,
7751 tree explicit_targs,
7752 tree access_path)
7753 {
7754 /* Here's what the standard says:
7756 [over.over]
7758 If the name is a function template, template argument deduction
7759 is done, and if the argument deduction succeeds, the deduced
7760 arguments are used to generate a single template function, which
7761 is added to the set of overloaded functions considered.
7763 Non-member functions and static member functions match targets of
7764 type "pointer-to-function" or "reference-to-function." Nonstatic
7765 member functions match targets of type "pointer-to-member
7766 function;" the function type of the pointer to member is used to
7767 select the member function from the set of overloaded member
7768 functions. If a nonstatic member function is selected, the
7769 reference to the overloaded function name is required to have the
7770 form of a pointer to member as described in 5.3.1.
7772 If more than one function is selected, any template functions in
7773 the set are eliminated if the set also contains a non-template
7774 function, and any given template function is eliminated if the
7775 set contains a second template function that is more specialized
7776 than the first according to the partial ordering rules 14.5.5.2.
7777 After such eliminations, if any, there shall remain exactly one
7778 selected function. */
7781 /* We store the matches in a TREE_LIST rooted here. The functions
7782 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7783 interoperability with most_specialized_instantiation. */
7785 tree fn;
7786 tree target_fn_type;
7788 /* By the time we get here, we should be seeing only real
7789 pointer-to-member types, not the internal POINTER_TYPE to
7790 METHOD_TYPE representation. */
7796 /* Check that the TARGET_TYPE is reasonable. */
7801 /* This is OK, too. */
7804 /* This is OK, too. This comes from a conversion to reference
7805 type. */
7807 else
7808 {
7814 }
7816 /* Non-member functions and static member functions match targets of type
7817 "pointer-to-function" or "reference-to-function." Nonstatic member
7818 functions match targets of type "pointer-to-member-function;" the
7819 function type of the pointer to member is used to select the member
7820 function from the set of overloaded member functions.
7822 So figure out the FUNCTION_TYPE that we want to match against. */
7825 /* If we can find a non-template function that matches, we can just
7826 use it. There's no point in generating template instantiations
7827 if we're just going to throw them out anyhow. But, of course, we
7828 can only do this when we don't *need* a template function. */
7831 {
7835 /* We're not looking for templates just yet. */
7839 /* We're looking for a non-static member, and this isn't
7840 one, or vice versa. */
7843 /* In C++17 we need the noexcept-qualifier to compare types. */
7848 /* See if there's a match. */
7853 }
7855 /* Now, if we've already got a match (or matches), there's no need
7856 to proceed to the template functions. But, if we don't have a
7857 match we need to look at them, too. */
7859 {
7860 tree target_arg_types;
7861 tree target_ret_type;
7864 tree arg;
7878 {
7880 tree instantiation;
7881 tree targs;
7884 /* We're only looking for templates. */
7889 /* We're not looking for a non-static member, and this is
7890 one, or vice versa. */
7895 /* If the template has a deduced return type, don't expose it to
7896 template argument deduction. */
7900 /* Try to do argument deduction. */
7907 /* Instantiation failed. */
7910 /* Constraints must be satisfied. This is done before
7911 return type deduction since that instantiates the
7912 function. */
7916 /* And now force instantiation to do return type deduction. */
7918 {
7924 }
7926 /* In C++17 we need the noexcept-qualifier to compare types. */
7930 /* See if there's a match. */
7935 }
7937 /* Now, remove all but the most specialized of the matches. */
7939 {
7944 NULL_TREE,
7945 NULL_TREE);
7946 }
7947 }
7949 /* Now we should have exactly one function in MATCHES. */
7951 {
7952 /* There were *no* matches. */
7954 {
7959 }
7961 }
7963 {
7964 /* There were too many matches. First check if they're all
7965 the same function. */
7970 /* For multi-versioned functions, more than one match is just fine and
7971 decls_match will return false as they are different. */
7979 {
7981 {
7985 /* Since print_candidates expects the functions in the
7986 TREE_VALUE slot, we flip them here. */
7991 }
7994 }
7995 }
7997 /* Good, exactly one match. Now, convert it to the correct type. */
8002 {
8008 auto_diagnostic_group d;
8011 {
8015 }
8016 }
8018 /* If a pointer to a function that is multi-versioned is requested, the
8019 pointer to the dispatcher function is returned instead. This works
8020 well because indirectly calling the function will dispatch the right
8021 function version at run-time. */
8023 {
8027 /* Mark all the versions corresponding to the dispatcher as used. */
8030 }
8032 /* If we're doing overload resolution purely for the purpose of
8033 determining conversion sequences, we should not consider the
8034 function used. If this conversion sequence is selected, the
8035 function will be marked as used at this point. */
8037 {
8038 /* Make =delete work with SFINAE. */
8043 }
8045 /* We could not check access to member functions when this
8046 expression was originally created since we did not know at that
8047 time to which function the expression referred. */
8049 {
8052 }
8056 else
8057 {
8058 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
8059 will mark the function as addressed, but here we must do it
8060 explicitly. */
8064 }
8065 }
8067 /* This function will instantiate the type of the expression given in
8068 RHS to match the type of LHSTYPE. If errors exist, then return
8069 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
8070 we complain on errors. If we are not complaining, never modify rhs,
8071 as overload resolution wants to try many possible instantiations, in
8072 the hope that at least one will work.
8074 For non-recursive calls, LHSTYPE should be a function, pointer to
8075 function, or a pointer to member function. */
8077 tree
8079 {
8086 {
8090 }
8093 {
8102 /* Microsoft allows `A::f' to be resolved to a
8103 pointer-to-member. */
8104 ;
8105 else
8106 {
8111 }
8112 }
8114 /* If we instantiate a template, and it is a A ?: C expression
8115 with omitted B, look through the SAVE_EXPR. */
8120 {
8123 }
8125 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
8126 deduce any type information. */
8128 {
8132 }
8134 /* There are only a few kinds of expressions that may have a type
8135 dependent on overload resolution. */
8141 /* This should really only be used when attempting to distinguish
8142 what sort of a pointer to function we have. For now, any
8143 arithmetic operation which is not supported on pointers
8144 is rejected as an error. */
8147 {
8149 {
8155 /* Do not lose object's side effects. */
8159 }
8166 /* This can happen if we are forming a pointer-to-member for a
8167 member template. */
8170 /* Fall through. */
8173 {
8177 return
8181 }
8185 return
8189 access_path);
8192 {
8197 }
8204 }
8206 }
8207 \f
8208 /* Return the name of the virtual function pointer field
8209 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8210 this may have to look back through base types to find the
8211 ultimate field name. (For single inheritance, these could
8212 all be the same name. Who knows for multiple inheritance). */
8214 static tree
8216 {
8222 {
8228 }
8236 }
8238 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8239 according to [class]:
8240 The class-name is also inserted
8241 into the scope of the class itself. For purposes of access checking,
8242 the inserted class name is treated as if it were a public member name. */
8244 void
8246 {
8263 }
8265 /* Returns 1 if TYPE contains only padding bytes. */
8267 int
8269 {
8277 }
8279 /* Returns true if TYPE contains no actual data, just various
8280 possible combinations of empty classes and possibly a vptr. */
8282 bool
8284 {
8286 {
8287 tree field;
8288 tree binfo;
8289 tree base_binfo;
8292 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8293 out, but we'd like to be able to check this before then. */
8304 /* An unnamed bit-field is not a data member. */
8309 }
8314 }
8316 /* Note that NAME was looked up while the current class was being
8317 defined and that the result of that lookup was DECL. */
8319 void
8321 {
8322 splay_tree names_used;
8324 /* If we're not defining a class, there's nothing to do. */
8330 /* If there's already a binding for this NAME, then we don't have
8331 anything to worry about. */
8344 }
8346 /* Note that NAME was declared (as DECL) in the current class. Check
8347 to see that the declaration is valid. */
8349 void
8351 {
8352 splay_tree names_used;
8353 splay_tree_node n;
8355 /* Look to see if we ever used this name. */
8356 names_used
8360 /* The C language allows members to be declared with a type of the same
8361 name, and the C++ standard says this diagnostic is not required. So
8362 allow it in extern "C" blocks unless predantic is specified.
8363 Allow it in all cases if -ms-extensions is specified. */
8369 {
8370 /* [basic.scope.class]
8372 A name N used in a class S shall refer to the same declaration
8373 in its context and when re-evaluated in the completed scope of
8374 S. */
8381 }
8382 }
8384 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8385 Secondary vtables are merged with primary vtables; this function
8386 will return the VAR_DECL for the primary vtable. */
8388 tree
8390 {
8391 tree decl;
8395 {
8398 }
8402 }
8405 /* Returns the binfo for the primary base of BINFO. If the resulting
8406 BINFO is a virtual base, and it is inherited elsewhere in the
8407 hierarchy, then the returned binfo might not be the primary base of
8408 BINFO in the complete object. Check BINFO_PRIMARY_P or
8409 BINFO_LOST_PRIMARY_P to be sure. */
8411 static tree
8413 {
8414 tree primary_base;
8421 }
8423 /* As above, but iterate until we reach the binfo that actually provides the
8424 vptr for BINFO. */
8426 static tree
8428 {
8432 {
8437 }
8439 }
8441 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8442 type. Note that the virtual inheritance might be above or below BINFO in
8443 the hierarchy. */
8445 bool
8447 {
8451 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8452 a morally virtual base. */
8455 }
8457 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8459 static int
8461 {
8465 }
8467 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8468 INDENT should be zero when called from the top level; it is
8469 incremented recursively. IGO indicates the next expected BINFO in
8470 inheritance graph ordering. */
8472 static tree
8474 dump_flags_t flags,
8475 tree binfo,
8476 tree igo,
8478 {
8480 tree base_binfo;
8488 {
8491 }
8506 {
8510 TFF_PLAIN_IDENTIFIER),
8512 }
8514 {
8517 }
8522 {
8526 {
8530 TFF_PLAIN_IDENTIFIER));
8531 }
8533 {
8537 TFF_PLAIN_IDENTIFIER));
8538 }
8540 {
8544 TFF_PLAIN_IDENTIFIER));
8545 }
8547 {
8551 TFF_PLAIN_IDENTIFIER));
8552 }
8556 }
8562 }
8564 /* Dump the BINFO hierarchy for T. */
8566 static void
8568 {
8580 }
8582 /* Debug interface to hierarchy dumping. */
8584 void
8586 {
8588 }
8590 static void
8592 {
8593 dump_flags_t flags;
8595 {
8598 }
8599 }
8601 static void
8603 {
8604 tree value;
8606 HOST_WIDE_INT elt;
8614 TFF_PLAIN_IDENTIFIER));
8621 }
8623 static void
8625 {
8626 dump_flags_t flags;
8633 {
8640 {
8645 }
8649 }
8652 }
8654 static void
8656 {
8657 dump_flags_t flags;
8664 {
8669 }
8672 }
8674 /* Dump a function or thunk and its thunkees. */
8676 static void
8678 {
8681 tree thunks;
8689 {
8699 else
8705 }
8709 }
8711 /* Dump the thunks for FN. */
8713 void
8715 {
8717 }
8719 /* Virtual function table initialization. */
8721 /* Create all the necessary vtables for T and its base classes. */
8723 static void
8725 {
8726 tree vbase;
8730 /* We lay out the primary and secondary vtables in one contiguous
8731 vtable. The primary vtable is first, followed by the non-virtual
8732 secondary vtables in inheritance graph order. */
8736 /* Then come the virtual bases, also in inheritance graph order. */
8738 {
8742 }
8746 }
8748 /* Initialize the vtable for BINFO with the INITS. */
8750 static void
8752 {
8753 tree decl;
8759 }
8761 /* Build the VTT (virtual table table) for T.
8762 A class requires a VTT if it has virtual bases.
8764 This holds
8765 1 - primary virtual pointer for complete object T
8766 2 - secondary VTTs for each direct non-virtual base of T which requires a
8767 VTT
8768 3 - secondary virtual pointers for each direct or indirect base of T which
8769 has virtual bases or is reachable via a virtual path from T.
8770 4 - secondary VTTs for each direct or indirect virtual base of T.
8772 Secondary VTTs look like complete object VTTs without part 4. */
8774 static void
8776 {
8777 tree type;
8778 tree vtt;
8779 tree index;
8782 /* Build up the initializers for the VTT. */
8787 /* If we didn't need a VTT, we're done. */
8791 /* Figure out the type of the VTT. */
8795 /* Now, build the VTT object itself. */
8798 /* Add the VTT to the vtables list. */
8803 }
8805 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8806 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8807 and CHAIN the vtable pointer for this binfo after construction is
8808 complete. VALUE can also be another BINFO, in which case we recurse. */
8810 static tree
8812 {
8813 tree vt;
8816 {
8822 else
8824 }
8827 }
8829 /* Data for secondary VTT initialization. */
8830 struct secondary_vptr_vtt_init_data
8831 {
8832 /* Is this the primary VTT? */
8835 /* Current index into the VTT. */
8836 tree index;
8838 /* Vector of initializers built up. */
8841 /* The type being constructed by this secondary VTT. */
8842 tree type_being_constructed;
8843 };
8845 /* Recursively build the VTT-initializer for BINFO (which is in the
8846 hierarchy dominated by T). INITS points to the end of the initializer
8847 list to date. INDEX is the VTT index where the next element will be
8848 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8849 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8850 for virtual bases of T. When it is not so, we build the constructor
8851 vtables for the BINFO-in-T variant. */
8853 static void
8856 {
8858 tree b;
8859 tree init;
8860 secondary_vptr_vtt_init_data data;
8863 /* We only need VTTs for subobjects with virtual bases. */
8867 /* We need to use a construction vtable if this is not the primary
8868 VTT. */
8870 {
8873 /* Record the offset in the VTT where this sub-VTT can be found. */
8875 }
8877 /* Add the address of the primary vtable for the complete object. */
8881 {
8884 }
8887 /* Recursively add the secondary VTTs for non-virtual bases. */
8892 /* Add secondary virtual pointers for all subobjects of BINFO with
8893 either virtual bases or reachable along a virtual path, except
8894 subobjects that are non-virtual primary bases. */
8904 /* data.inits might have grown as we added secondary virtual pointers.
8905 Make sure our caller knows about the new vector. */
8909 /* Add the secondary VTTs for virtual bases in inheritance graph
8910 order. */
8912 {
8917 }
8918 else
8919 /* Remove the ctor vtables we created. */
8921 }
8923 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8924 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8926 static tree
8928 {
8931 /* We don't care about bases that don't have vtables. */
8935 /* We're only interested in proper subobjects of the type being
8936 constructed. */
8940 /* We're only interested in bases with virtual bases or reachable
8941 via a virtual path from the type being constructed. */
8946 /* We're not interested in non-virtual primary bases. */
8950 /* Record the index where this secondary vptr can be found. */
8952 {
8957 {
8958 /* It's a primary virtual base, and this is not a
8959 construction vtable. Find the base this is primary of in
8960 the inheritance graph, and use that base's vtable
8961 now. */
8964 }
8965 }
8967 /* Add the initializer for the secondary vptr itself. */
8970 /* Advance the vtt index. */
8975 }
8977 /* Called from build_vtt_inits via dfs_walk. After building
8978 constructor vtables and generating the sub-vtt from them, we need
8979 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8980 binfo of the base whose sub vtt was generated. */
8982 static tree
8984 {
8988 /* If this class has no vtable, none of its bases do. */
8992 /* This might be a primary base, so have no vtable in this
8993 hierarchy. */
8996 /* If we scribbled the construction vtable vptr into BINFO, clear it
8997 out now. */
9003 }
9005 /* Build the construction vtable group for BINFO which is in the
9006 hierarchy dominated by T. */
9008 static void
9010 {
9011 tree type;
9012 tree vtbl;
9013 tree id;
9014 tree vbase;
9017 /* See if we've already created this construction vtable group. */
9023 /* Build a version of VTBL (with the wrong type) for use in
9024 constructing the addresses of secondary vtables in the
9025 construction vtable group. */
9028 /* Don't export construction vtables from shared libraries. Even on
9029 targets that don't support hidden visibility, this tells
9030 can_refer_decl_in_current_unit_p not to assume that it's safe to
9031 access from a different compilation unit (bz 54314). */
9039 /* Add the vtables for each of our virtual bases using the vbase in T
9040 binfo. */
9042 vbase;
9044 {
9045 tree b;
9052 }
9054 /* Figure out the type of the construction vtable. */
9061 /* Initialize the construction vtable. */
9065 }
9067 /* Add the vtbl initializers for BINFO (and its bases other than
9068 non-virtual primaries) to the list of INITS. BINFO is in the
9069 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
9070 the constructor the vtbl inits should be accumulated for. (If this
9071 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
9072 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
9073 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
9074 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
9075 but are not necessarily the same in terms of layout. */
9077 static void
9079 tree orig_binfo,
9080 tree rtti_binfo,
9081 tree vtbl,
9082 tree t,
9084 {
9086 tree base_binfo;
9091 /* If it doesn't have a vptr, we don't do anything. */
9095 /* If we're building a construction vtable, we're not interested in
9096 subobjects that don't require construction vtables. */
9102 /* Build the initializers for the BINFO-in-T vtable. */
9105 /* Walk the BINFO and its bases. We walk in preorder so that as we
9106 initialize each vtable we can figure out at what offset the
9107 secondary vtable lies from the primary vtable. We can't use
9108 dfs_walk here because we need to iterate through bases of BINFO
9109 and RTTI_BINFO simultaneously. */
9111 {
9112 /* Skip virtual bases. */
9118 inits);
9119 }
9120 }
9122 /* Called from accumulate_vtbl_inits. Adds the initializers for the
9123 BINFO vtable to L. */
9125 static void
9127 tree orig_binfo,
9128 tree rtti_binfo,
9129 tree orig_vtbl,
9130 tree t,
9132 {
9139 {
9140 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9141 primary virtual base. If it is not the same primary in
9142 the hierarchy of T, we'll need to generate a ctor vtable
9143 for it, to place at its location in T. If it is the same
9144 primary, we still need a VTT entry for the vtable, but it
9145 should point to the ctor vtable for the base it is a
9146 primary for within the sub-hierarchy of RTTI_BINFO.
9148 There are three possible cases:
9150 1) We are in the same place.
9151 2) We are a primary base within a lost primary virtual base of
9152 RTTI_BINFO.
9153 3) We are primary to something not a base of RTTI_BINFO. */
9155 tree b;
9158 /* First, look through the bases we are primary to for RTTI_BINFO
9159 or a virtual base. */
9162 {
9167 }
9168 /* If we run out of primary links, keep looking down our
9169 inheritance chain; we might be an indirect primary. */
9173 found:
9175 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9176 base B and it is a base of RTTI_BINFO, this is case 2. In
9177 either case, we share our vtable with LAST, i.e. the
9178 derived-most base within B of which we are a primary. */
9181 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9182 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9183 binfo_ctor_vtable after everything's been set up. */
9186 /* Otherwise, this is case 3 and we get our own. */
9187 }
9194 {
9195 tree index;
9198 /* Add the initializer for this vtable. */
9202 /* Figure out the position to which the VPTR should point. */
9208 }
9211 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9212 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9213 straighten this out. */
9216 /* Throw away any unneeded intializers. */
9218 else
9219 /* For an ordinary vtable, set BINFO_VTABLE. */
9221 }
9226 /* Construct the initializer for BINFO's virtual function table. BINFO
9227 is part of the hierarchy dominated by T. If we're building a
9228 construction vtable, the ORIG_BINFO is the binfo we should use to
9229 find the actual function pointers to put in the vtable - but they
9230 can be overridden on the path to most-derived in the graph that
9231 ORIG_BINFO belongs. Otherwise,
9232 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9233 BINFO that should be indicated by the RTTI information in the
9234 vtable; it will be a base class of T, rather than T itself, if we
9235 are building a construction vtable.
9237 The value returned is a TREE_LIST suitable for wrapping in a
9238 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9239 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9240 number of non-function entries in the vtable.
9242 It might seem that this function should never be called with a
9243 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9244 base is always subsumed by a derived class vtable. However, when
9245 we are building construction vtables, we do build vtables for
9246 primary bases; we need these while the primary base is being
9247 constructed. */
9249 static void
9251 tree orig_binfo,
9252 tree t,
9253 tree rtti_binfo,
9256 {
9257 tree v;
9258 vtbl_init_data vid;
9260 tree vbinfo;
9264 /* Initialize VID. */
9272 /* The first vbase or vcall offset is at index -3 in the vtable. */
9275 /* Add entries to the vtable for RTTI. */
9278 /* Create an array for keeping track of the functions we've
9279 processed. When we see multiple functions with the same
9280 signature, we share the vcall offsets. */
9282 /* Add the vcall and vbase offset entries. */
9285 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9286 build_vbase_offset_vtbl_entries. */
9291 /* If the target requires padding between data entries, add that now. */
9293 {
9298 /* Move data entries into their new positions and add padding
9299 after the new positions. Iterate backwards so we don't
9300 overwrite entries that we would need to process later. */
9303 ix--)
9304 {
9312 {
9316 null_pointer_node);
9317 }
9318 }
9319 }
9324 /* The initializers for virtual functions were built up in reverse
9325 order. Straighten them out and add them to the running list in one
9326 step. */
9335 /* Go through all the ordinary virtual functions, building up
9336 initializers. */
9338 {
9339 tree delta;
9340 tree vcall_index;
9348 {
9352 {
9355 }
9357 }
9359 /* If the only definition of this function signature along our
9360 primary base chain is from a lost primary, this vtable slot will
9361 never be used, so just zero it out. This is important to avoid
9362 requiring extra thunks which cannot be generated with the function.
9364 We first check this in update_vtable_entry_for_fn, so we handle
9365 restored primary bases properly; we also need to do it here so we
9366 zero out unused slots in ctor vtables, rather than filling them
9367 with erroneous values (though harmless, apart from relocation
9368 costs). */
9373 {
9374 /* Pull the offset for `this', and the function to call, out of
9375 the list. */
9382 /* You can't call an abstract virtual function; it's abstract.
9383 So, we replace these functions with __pure_virtual. */
9385 {
9388 {
9390 abort_fndecl_addr
9394 }
9395 }
9396 /* Likewise for deleted virtuals. */
9398 {
9400 {
9404 dvirt_fn = push_library_fn
9408 }
9413 }
9414 else
9415 {
9417 {
9422 }
9423 /* Take the address of the function, considering it to be of an
9424 appropriate generic type. */
9428 /* Don't refer to a virtual destructor from a constructor
9429 vtable or a vtable for an abstract class, since destroying
9430 an object under construction is undefined behavior and we
9431 don't want it to be considered a candidate for speculative
9432 devirtualization. But do create the thunk for ABI
9433 compliance. */
9438 }
9439 }
9441 /* And add it to the chain of initializers. */
9443 {
9448 else
9450 {
9456 }
9457 }
9458 else
9460 }
9461 }
9463 /* Adds to vid->inits the initializers for the vbase and vcall
9464 offsets in BINFO, which is in the hierarchy dominated by T. */
9466 static void
9468 {
9469 tree b;
9471 /* If this is a derived class, we must first create entries
9472 corresponding to the primary base class. */
9477 /* Add the vbase entries for this base. */
9479 /* Add the vcall entries for this base. */
9481 }
9483 /* Returns the initializers for the vbase offset entries in the vtable
9484 for BINFO (which is part of the class hierarchy dominated by T), in
9485 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9486 where the next vbase offset will go. */
9488 static void
9490 {
9491 tree vbase;
9492 tree t;
9493 tree non_primary_binfo;
9495 /* If there are no virtual baseclasses, then there is nothing to
9496 do. */
9502 /* We might be a primary base class. Go up the inheritance hierarchy
9503 until we find the most derived class of which we are a primary base:
9504 it is the offset of that which we need to use. */
9507 {
9508 tree b;
9510 /* If we have reached a virtual base, then it must be a primary
9511 base (possibly multi-level) of vid->binfo, or we wouldn't
9512 have called build_vcall_and_vbase_vtbl_entries for it. But it
9513 might be a lost primary, so just skip down to vid->binfo. */
9515 {
9518 }
9524 }
9526 /* Go through the virtual bases, adding the offsets. */
9528 vbase;
9530 {
9531 tree b;
9532 tree delta;
9537 /* Find the instance of this virtual base in the complete
9538 object. */
9541 /* If we've already got an offset for this virtual base, we
9542 don't need another one. */
9547 /* Figure out where we can find this vbase offset. */
9556 /* The vbase offset had better be the same. */
9559 /* The next vbase will come at a more negative offset. */
9563 /* The initializer is the delta from BINFO to this virtual base.
9564 The vbase offsets go in reverse inheritance-graph order, and
9565 we are walking in inheritance graph order so these end up in
9566 the right order. */
9573 }
9574 }
9576 /* Adds the initializers for the vcall offset entries in the vtable
9577 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9578 to VID->INITS. */
9580 static void
9582 {
9583 /* We only need these entries if this base is a virtual base. We
9584 compute the indices -- but do not add to the vtable -- when
9585 building the main vtable for a class. */
9588 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9589 correspond to VID->DERIVED), we are building a primary
9590 construction virtual table. Since this is a primary
9591 virtual table, we do not need the vcall offsets for
9592 BINFO. */
9594 {
9595 /* We need a vcall offset for each of the virtual functions in this
9596 vtable. For example:
9598 class A { virtual void f (); };
9599 class B1 : virtual public A { virtual void f (); };
9600 class B2 : virtual public A { virtual void f (); };
9601 class C: public B1, public B2 { virtual void f (); };
9603 A C object has a primary base of B1, which has a primary base of A. A
9604 C also has a secondary base of B2, which no longer has a primary base
9605 of A. So the B2-in-C construction vtable needs a secondary vtable for
9606 A, which will adjust the A* to a B2* to call f. We have no way of
9607 knowing what (or even whether) this offset will be when we define B2,
9608 so we store this "vcall offset" in the A sub-vtable and look it up in
9609 a "virtual thunk" for B2::f.
9611 We need entries for all the functions in our primary vtable and
9612 in our non-virtual bases' secondary vtables. */
9614 /* If we are just computing the vcall indices -- but do not need
9615 the actual entries -- not that. */
9618 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9620 }
9621 }
9623 /* Build vcall offsets, starting with those for BINFO. */
9625 static void
9627 {
9629 tree primary_binfo;
9630 tree base_binfo;
9632 /* Don't walk into virtual bases -- except, of course, for the
9633 virtual base for which we are building vcall offsets. Any
9634 primary virtual base will have already had its offsets generated
9635 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9639 /* If BINFO has a primary base, process it first. */
9644 /* Add BINFO itself to the list. */
9647 /* Scan the non-primary bases of BINFO. */
9651 }
9653 /* Called from build_vcall_offset_vtbl_entries_r. */
9655 static void
9657 {
9658 /* Make entries for the rest of the virtuals. */
9659 tree orig_fn;
9661 /* The ABI requires that the methods be processed in declaration
9662 order. */
9664 orig_fn;
9668 }
9670 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9672 static void
9674 {
9676 tree vcall_offset;
9677 tree derived_entry;
9679 /* If there is already an entry for a function with the same
9680 signature as FN, then we do not need a second vcall offset.
9681 Check the list of functions already present in the derived
9682 class vtable. */
9684 {
9686 /* We only use one vcall offset for virtual destructors,
9687 even though there are two virtual table entries. */
9691 }
9693 /* If we are building these vcall offsets as part of building
9694 the vtable for the most derived class, remember the vcall
9695 offset. */
9697 {
9700 }
9702 /* The next vcall offset will be found at a more negative
9703 offset. */
9707 /* Keep track of this function. */
9711 {
9712 tree base;
9713 tree fn;
9715 /* Find the overriding function. */
9719 else
9720 {
9723 /* The vbase we're working on is a primary base of
9724 vid->binfo. But it might be a lost primary, so its
9725 BINFO_OFFSET might be wrong, so we just use the
9726 BINFO_OFFSET from vid->binfo. */
9732 vcall_offset);
9733 }
9734 /* Add the initializer to the vtable. */
9736 }
9737 }
9739 /* Return vtbl initializers for the RTTI entries corresponding to the
9740 BINFO's vtable. The RTTI entries should indicate the object given
9741 by VID->rtti_binfo. */
9743 static void
9745 {
9746 tree b;
9747 tree t;
9748 tree offset;
9749 tree decl;
9750 tree init;
9754 /* To find the complete object, we will first convert to our most
9755 primary base, and then add the offset in the vtbl to that value. */
9760 /* The second entry is the address of the typeinfo object. */
9763 else
9766 /* Convert the declaration to a type that can be stored in the
9767 vtable. */
9771 /* Add the offset-to-top entry. It comes earlier in the vtable than
9772 the typeinfo entry. Convert the offset to look like a
9773 function pointer, so that we can put it in the vtable. */
9776 }
9778 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9779 accessibility. */
9781 bool
9783 {
9786 }
9788 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9790 bool
9792 {
9796 }
9798 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9799 class between them, if any. */
9801 tree
9803 {
9815 {
9818 }
9822 }