| blob | ab68b9be42a661c18feb4c159d1854f05c1279a0 |
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. */
148 /* Used by find_flexarrays and related functions. */
199 tree *);
209 splay_tree_key k2);
218 /* Return a COND_EXPR that executes TRUE_STMT if this execution of the
219 'structor is in charge of 'structing virtual bases, or FALSE_STMT
220 otherwise. */
222 tree
224 {
234 }
236 /* Convert to or from a base subobject. EXPR is an expression of type
237 `A' or `A*', an expression of type `B' or `B*' is returned. To
238 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
239 the B base instance within A. To convert base A to derived B, CODE
240 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
241 In this latter case, A must not be a morally virtual base of B.
242 NONNULL is true if EXPR is known to be non-NULL (this is only
243 needed when EXPR is of pointer type). CV qualifiers are preserved
244 from EXPR. */
246 tree
248 tree expr,
249 tree binfo,
251 tsubst_flags_t complain)
252 {
255 tree probe;
256 tree offset;
257 tree target_type;
259 tree ptr_target_type;
270 {
276 }
284 {
285 /* This can happen when adjust_result_of_qualified_name_lookup can't
286 find a unique base binfo in a call to a member function. We
287 couldn't give the diagnostic then since we might have been calling
288 a static member function, so we do it now. In other cases, eg.
289 during error recovery (c++/71979), we may not have a base at all. */
291 {
295 }
297 }
304 /* Nothing to do. */
308 {
310 {
312 {
315 "pointer to derived class %qT because the base is "
317 else
321 }
322 else
323 {
329 else
333 }
334 }
336 }
339 {
341 /* This must happen before the call to save_expr. */
343 }
344 else
350 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
351 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
352 expression returned matches the input. */
353 target_type = cp_build_qualified_type
357 /* Do we need to look in the vtable for the real offset? */
360 /* Don't bother with the calculations inside sizeof; they'll ICE if the
361 source type is incomplete and the pointer value doesn't matter. In a
362 template (even in instantiate_non_dependent_expr), we don't have vtables
363 set up properly yet, and the value doesn't matter there either; we're
364 just interested in the result of overload resolution. */
366 || processing_template_decl
368 {
371 }
374 {
380 }
382 /* If we're in an NSDMI, we don't have the full constructor context yet
383 that we need for converting to a virtual base, so just build a stub
384 CONVERT_EXPR and expand it later in bot_replace. */
387 {
391 }
393 /* Do we need to check for a null pointer? */
395 {
396 /* If we know the conversion will not actually change the value
397 of EXPR, then we can avoid testing the expression for NULL.
398 We have to avoid generating a COMPONENT_REF for a base class
399 field, because other parts of the compiler know that such
400 expressions are always non-NULL. */
404 }
406 /* Protect against multiple evaluation if necessary. */
410 /* Now that we've saved expr, build the real null test. */
412 {
416 /* This is a compiler generated comparison, don't emit
417 e.g. -Wnonnull-compare warning for it. */
419 }
421 /* If this is a simple base reference, express it as a COMPONENT_REF. */
423 /* We don't build base fields for empty bases, and they aren't very
424 interesting to the optimizers anyway. */
426 {
435 }
438 {
439 /* Going via virtual base V_BINFO. We need the static offset
440 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
441 V_BINFO. That offset is an entry in D_BINFO's vtable. */
442 tree v_offset;
445 {
446 /* In a base member initializer, we cannot rely on the
447 vtable being set up. We have to indirect via the
448 vtt_parm. */
449 tree t;
455 }
456 else
457 {
461 {
466 }
469 }
477 v_offset);
489 /* Negative fixed_type_p means this is a constructor or destructor;
490 virtual base layout is fixed in in-charge [cd]tors, but not in
491 base [cd]tors. */
492 offset = build_if_in_charge
494 v_offset);
495 else
497 }
505 {
510 }
511 else
514 indout:
516 {
520 }
522 out:
528 }
530 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
531 Perform a derived-to-base conversion by recursively building up a
532 sequence of COMPONENT_REFs to the appropriate base fields. */
534 static tree
536 {
539 tree field;
542 {
543 tree temp;
547 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
548 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
549 an lvalue in the front end; only _DECLs and _REFs are lvalues
550 in the back end. */
556 }
558 /* Recurse. */
563 /* Is this the base field created by build_base_field? */
567 /* If we're looking for a field in the most-derived class,
568 also check the field offset; we can have two base fields
569 of the same type if one is an indirect virtual base and one
570 is a direct non-virtual base. */
574 {
575 /* We don't use build_class_member_access_expr here, as that
576 has unnecessary checks, and more importantly results in
577 recursive calls to dfs_walk_once. */
583 /* Mark the expression const or volatile, as appropriate.
584 Even though we've dealt with the type above, we still have
585 to mark the expression itself. */
592 }
594 /* Didn't find the base field?!? */
596 }
598 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
599 type is a class type or a pointer to a class type. In the former
600 case, TYPE is also a class type; in the latter it is another
601 pointer type. If CHECK_ACCESS is true, an error message is emitted
602 if TYPE is inaccessible. If OBJECT has pointer type, the value is
603 assumed to be non-NULL. */
605 tree
607 tsubst_flags_t complain)
608 {
609 tree binfo;
610 tree object_type;
613 {
616 }
617 else
626 }
628 /* EXPR is an expression with unqualified class type. BASE is a base
629 binfo of that class type. Returns EXPR, converted to the BASE
630 type. This function assumes that EXPR is the most derived class;
631 therefore virtual bases can be found at their static offsets. */
633 tree
635 {
636 tree expr_type;
640 {
641 /* If this is a non-empty base, use a COMPONENT_REF. */
645 /* We use fold_build2 and fold_convert below to simplify the trees
646 provided to the optimizers. It is not safe to call these functions
647 when processing a template because they do not handle C++-specific
648 trees. */
656 }
659 }
661 \f
662 tree
664 {
668 /* Can happen in case of duplicate base types (c++/59082). */
672 /* First, convert to the requested type. */
677 /* Second, the requested type may not be the owner of its own vptr.
678 If not, convert to the base class that owns it. We cannot use
679 convert_to_base here, because VCONTEXT may appear more than once
680 in the inheritance hierarchy of TYPE, and thus direct conversion
681 between the types may be ambiguous. Following the path back up
682 one step at a time via primary bases avoids the problem. */
686 {
689 }
692 }
694 /* Given an object INSTANCE, return an expression which yields the
695 vtable element corresponding to INDEX. There are many special
696 cases for INSTANCE which we take care of here, mainly to avoid
697 creating extra tree nodes when we don't have to. */
699 static tree
701 {
702 tree aref;
705 /* Try to figure out what a reference refers to, and
706 access its virtual function table directly. */
714 {
719 }
728 }
730 tree
732 {
736 }
738 /* Given a stable object pointer INSTANCE_PTR, return an expression which
739 yields a function pointer corresponding to vtable element INDEX. */
741 tree
743 {
744 tree aref;
747 idx);
749 /* When using function descriptors, the address of the
750 vtable entry is treated as a function pointer. */
755 /* Remember this as a method reference, for later devirtualization. */
759 }
761 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
762 for the given TYPE. */
764 static tree
766 {
768 }
770 /* DECL is an entity associated with TYPE, like a virtual table or an
771 implicitly generated constructor. Determine whether or not DECL
772 should have external or internal linkage at the object file
773 level. This routine does not deal with COMDAT linkage and other
774 similar complexities; it simply sets TREE_PUBLIC if it possible for
775 entities in other translation units to contain copies of DECL, in
776 the abstract. */
778 void
780 {
783 }
785 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
786 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
787 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
789 static tree
791 {
792 tree decl;
795 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
796 now to avoid confusion in mangle_decl. */
807 /* The vtable has not been defined -- yet. */
811 /* Mark the VAR_DECL node representing the vtable itself as a
812 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
813 is rather important that such things be ignored because any
814 effort to actually generate DWARF for them will run into
815 trouble when/if we encounter code like:
817 #pragma interface
818 struct S { virtual void member (); };
820 because the artificial declaration of the vtable itself (as
821 manufactured by the g++ front end) will say that the vtable is
822 a static member of `S' but only *after* the debug output for
823 the definition of `S' has already been output. This causes
824 grief because the DWARF entry for the definition of the vtable
825 will try to refer back to an earlier *declaration* of the
826 vtable as a static member of `S' and there won't be one. We
827 might be able to arrange to have the "vtable static member"
828 attached to the member list for `S' before the debug info for
829 `S' get written (which would solve the problem) but that would
830 require more intrusive changes to the g++ front end. */
834 }
836 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
837 or even complete. If this does not exist, create it. If COMPLETE is
838 nonzero, then complete the definition of it -- that will render it
839 impossible to actually build the vtable, but is useful to get at those
840 which are known to exist in the runtime. */
842 tree
844 {
845 tree decl;
854 {
857 }
860 }
862 /* Build the primary virtual function table for TYPE. If BINFO is
863 non-NULL, build the vtable starting with the initial approximation
864 that it is the same as the one which is the head of the association
865 list. Returns a nonzero value if a new vtable is actually
866 created. */
868 static int
870 {
871 tree decl;
872 tree virtuals;
877 {
879 /* We have already created a vtable for this base, so there's
880 no need to do it again. */
887 }
888 else
889 {
892 }
894 /* Initialize the association list for this type, based
895 on our first approximation. */
900 }
902 /* Give BINFO a new virtual function table which is initialized
903 with a skeleton-copy of its original initialization. The only
904 entry that changes is the `delta' entry, so we can really
905 share a lot of structure.
907 FOR_TYPE is the most derived type which caused this table to
908 be needed.
910 Returns nonzero if we haven't met BINFO before.
912 The order in which vtables are built (by calling this function) for
913 an object must remain the same, otherwise a binary incompatibility
914 can result. */
916 static int
918 {
920 /* We already created a vtable for this base. There's no need to
921 do it again. */
924 /* Remember that we've created a vtable for this BINFO, so that we
925 don't try to do so again. */
928 /* Make fresh virtual list, so we can smash it later. */
931 /* Secondary vtables are laid out as part of the same structure as
932 the primary vtable. */
935 }
937 /* Create a new vtable for BINFO which is the hierarchy dominated by
938 T. Return nonzero if we actually created a new vtable. */
940 static int
942 {
944 /* In this case, it is *type*'s vtable we are modifying. We start
945 with the approximation that its vtable is that of the
946 immediate base class. */
948 else
949 /* This is our very own copy of `basetype' to play with. Later,
950 we will fill in all the virtual functions that override the
951 virtual functions in these base classes which are not defined
952 by the current type. */
954 }
956 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
957 (which is in the hierarchy dominated by T) list FNDECL as its
958 BV_FN. DELTA is the required constant adjustment from the `this'
959 pointer where the vtable entry appears to the `this' required when
960 the function is actually called. */
962 static void
964 tree binfo,
965 tree fndecl,
966 tree delta,
968 {
969 tree v;
975 {
976 /* We need a new vtable for BINFO. */
978 {
979 /* If we really did make a new vtable, we also made a copy
980 of the BINFO_VIRTUALS list. Now, we have to find the
981 corresponding entry in that list. */
986 }
991 }
992 }
994 \f
995 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
996 METHOD is being injected via a using_decl. Returns true if the
997 method could be added to the method vec. */
999 bool
1001 {
1010 /* Check to see if we've already got this method. */
1012 {
1014 tree fn_type;
1015 tree method_type;
1016 tree parms1;
1017 tree parms2;
1022 /* Two using-declarations can coexist, we'll complain about ambiguity in
1023 overload resolution. */
1025 /* Except handle inherited constructors specially. */
1029 /* [over.load] Member function declarations with the
1030 same name and the same parameter types cannot be
1031 overloaded if any of them is a static member
1032 function declaration.
1034 [over.load] Member function declarations with the same name and
1035 the same parameter-type-list as well as member function template
1036 declarations with the same name, the same parameter-type-list, and
1037 the same template parameter lists cannot be overloaded if any of
1038 them, but not all, have a ref-qualifier.
1040 [namespace.udecl] When a using-declaration brings names
1041 from a base class into a derived class scope, member
1042 functions in the derived class override and/or hide member
1043 functions with the same name and parameter types in a base
1044 class (rather than conflicting). */
1050 /* Compare the quals on the 'this' parm. Don't compare
1051 the whole types, as used functions are treated as
1052 coming from the using class in overload resolution. */
1055 /* Either both or neither need to be ref-qualified for
1056 differing quals to allow overloading. */
1063 /* For templates, the return type and template parameters
1064 must be identical. */
1077 /* Bring back parameters omitted from an inherited ctor. */
1088 {
1089 /* If these are versions of the same function, process and
1090 move on. */
1096 {
1098 {
1102 {
1104 {
1105 /* Inheriting the same constructor along different
1106 paths, combine them. */
1107 SET_DECL_INHERITED_CTOR
1110 /* And discard the new one. */
1112 }
1113 else
1114 /* Inherited ctors can coexist until overload
1115 resolution. */
1117 }
1123 basef);
1124 }
1125 /* Otherwise defer to the other function. */
1127 }
1130 /* Defer to the local function. */
1134 {
1135 /* Remove the inherited constructor. */
1138 }
1139 else
1140 {
1146 }
1147 }
1148 }
1150 /* A class should never have more than one destructor. */
1162 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1168 }
1170 /* Subroutines of finish_struct. */
1172 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1173 legit, otherwise return 0. */
1175 static int
1177 {
1178 tree elem;
1186 {
1188 {
1192 else
1195 }
1196 else
1197 {
1198 /* They're changing the access to the same thing they changed
1199 it to before. That's OK. */
1200 ;
1201 }
1202 }
1203 else
1204 {
1206 tf_warning_or_error);
1209 }
1211 }
1213 /* Return the access node for DECL's access in its enclosing class. */
1215 tree
1217 {
1221 }
1223 /* Process the USING_DECL, which is a member of T. */
1225 static void
1227 {
1232 tree old_value;
1237 tf_warning_or_error);
1239 {
1244 else
1246 }
1254 ;
1256 {
1258 /* It's OK to use functions from a base when there are functions with
1260 else
1261 {
1268 }
1269 }
1271 {
1278 }
1280 /* Make type T see field decl FDECL with access ACCESS. */
1283 {
1286 }
1287 else
1289 }
1290 \f
1291 /* Data structure for find_abi_tags_r, below. */
1293 struct abi_tag_data
1294 {
1298 };
1300 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1301 in the context of P. TAG can be either an identifier (the DECL_NAME of
1302 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1304 static void
1306 {
1308 {
1310 {
1311 /* We're collecting tags from template arguments or from
1312 the type of a variable or function return type. */
1315 /* Don't inherit this tag multiple times. */
1319 {
1320 /* Tags inherited from type template arguments are only used
1321 to avoid warnings. */
1324 }
1325 /* For functions and variables we want to warn, too. */
1326 }
1328 /* Otherwise we're diagnosing missing tags. */
1330 {
1335 }
1337 {
1341 }
1343 {
1348 }
1349 else
1350 {
1354 {
1358 }
1359 }
1360 }
1361 }
1363 /* Find all the ABI tags in the attribute list ATTR and either call
1364 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1366 static void
1368 {
1375 {
1380 else
1382 }
1383 }
1385 /* Find all the ABI tags on T and its enclosing scopes and either call
1386 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1388 static void
1390 {
1392 {
1393 tree attr;
1395 {
1398 }
1399 else
1400 {
1403 }
1405 }
1406 }
1408 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1409 types with ABI tags, add the corresponding identifiers to the VEC in
1410 *DATA and set IDENTIFIER_MARKED. */
1412 static tree
1414 {
1418 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1419 anyway, but let's make sure of it. */
1427 }
1429 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1430 IDENTIFIER_MARKED on its ABI tags. */
1432 static tree
1434 {
1438 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1439 anyway, but let's make sure of it. */
1447 }
1449 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1450 scopes. */
1452 static void
1454 {
1457 {
1460 {
1461 /* Template arguments are part of the signature. */
1464 {
1467 }
1468 }
1470 /* A function's parameter types are part of the signature, so
1471 we don't need to inherit any tags that are also in them. */
1476 }
1477 }
1479 /* Check that T has all the ABI tags that subobject SUBOB has, or
1480 warn if not. If T is a (variable or function) declaration, also
1481 return any missing tags, and add them to T if JUST_CHECKING is false. */
1483 static tree
1485 {
1493 /* No need to worry about things local to this TU. */
1509 {
1512 }
1513 else
1514 {
1518 else
1522 }
1527 }
1529 /* Check that DECL has all the ABI tags that are used in parts of its type
1530 that are not reflected in its mangled name. */
1532 void
1534 {
1541 }
1543 /* Return any ABI tags that are used in parts of the type of DECL
1544 that are not reflected in its mangled name. This function is only
1545 used in backward-compatible mangling for ABI <11. */
1547 tree
1549 {
1553 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1554 that we can use this function for setting need_abi_warning
1555 regardless of the current flag_abi_version. */
1558 else
1560 }
1562 void
1564 {
1574 {
1577 {
1581 }
1582 }
1584 // If we found some tags on our template arguments, add them to our
1585 // abi_tag attribute.
1587 {
1591 else
1595 }
1598 }
1600 /* Return true, iff class T has a non-virtual destructor that is
1601 accessible from outside the class heirarchy (i.e. is public, or
1602 there's a suitable friend. */
1604 static bool
1606 {
1609 /* An implicitly declared destructor is always public. And,
1610 if it were virtual, we would have created it by now. */
1625 }
1627 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1628 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1629 properties of the bases. */
1631 static void
1635 {
1639 tree base_binfo;
1640 tree binfo;
1650 {
1659 /* If any base class is non-literal, so is the derived class. */
1663 /* If the base class doesn't have copy constructors or
1664 assignment operators that take const references, then the
1665 derived class cannot have such a member automatically
1666 generated. */
1675 /* A virtual base does not effect nearly emptiness. */
1676 ;
1678 {
1680 /* And if there is more than one nearly empty base, then the
1681 derived class is not nearly empty either. */
1683 else
1684 /* Remember we've seen one. */
1686 }
1688 /* If the base class is not empty or nearly empty, then this
1689 class cannot be nearly empty. */
1692 /* A lot of properties from the bases also apply to the derived
1693 class. */
1710 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1713 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1719 /* A standard-layout class is a class that:
1720 ...
1721 * has no non-standard-layout base classes, */
1724 {
1725 tree basefield;
1726 /* ...has no base classes of the same type as the first non-static
1727 data member... */
1729 && (same_type_ignoring_top_level_qualifiers_p
1732 else
1733 /* ...either has no non-static data members in the most-derived
1734 class and at most one base class with non-static data
1735 members, or has no base classes with non-static data
1736 members */
1742 {
1745 else
1748 }
1749 }
1751 /* Don't bother collecting tm attributes if transactional memory
1752 support is not enabled. */
1754 {
1758 }
1761 }
1763 /* If one of the base classes had TM attributes, and the current class
1764 doesn't define its own, then the current class inherits one. */
1766 {
1769 }
1770 }
1772 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1773 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1774 that have had a nearly-empty virtual primary base stolen by some
1775 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1776 T. */
1778 static void
1780 {
1784 tree base_binfo;
1786 /* Determine the primary bases of our bases. */
1789 {
1792 /* See if we're the non-virtual primary of our inheritance
1793 chain. */
1795 {
1802 /* We are the primary binfo. */
1804 }
1805 /* Determine if we have a virtual primary base, and mark it so.
1806 */
1808 {
1812 /* Someone already claimed this base. */
1814 else
1815 {
1816 tree delta;
1821 /* A virtual binfo might have been copied from within
1822 another hierarchy. As we're about to use it as a
1823 primary base, make sure the offsets match. */
1831 }
1832 }
1833 }
1835 /* First look for a dynamic direct non-virtual base. */
1837 {
1841 {
1844 }
1845 }
1847 /* A "nearly-empty" virtual base class can be the primary base
1848 class, if no non-virtual polymorphic base can be found. Look for
1849 a nearly-empty virtual dynamic base that is not already a primary
1850 base of something in the hierarchy. If there is no such base,
1851 just pick the first nearly-empty virtual base. */
1857 {
1859 {
1860 /* Found one that is not primary. */
1863 }
1865 /* Remember the first candidate. */
1867 }
1869 found:
1870 /* If we've got a primary base, use it. */
1872 {
1877 /* We are stealing a primary base. */
1881 {
1882 tree delta;
1885 /* A virtual binfo might have been copied from within
1886 another hierarchy. As we're about to use it as a primary
1887 base, make sure the offsets match. */
1892 }
1899 }
1900 }
1902 /* Update the variant types of T. */
1904 void
1906 {
1907 tree variants;
1913 variants;
1915 {
1916 /* These fields are in the _TYPE part of the node, not in
1917 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1927 /* Copy whatever these are holding today. */
1930 }
1931 }
1933 /* KLASS is a class that we're applying may_alias to after the body is
1934 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
1935 canonical type(s) will be implicitly updated. */
1937 static void
1939 {
1948 }
1950 /* Early variant fixups: we apply attributes at the beginning of the class
1951 definition, and we need to fix up any variants that have already been
1952 made via elaborated-type-specifier so that check_qualified_type works. */
1954 void
1956 {
1957 tree variants;
1971 variants;
1973 {
1974 /* These are the two fields that check_qualified_type looks at and
1975 are affected by attributes. */
1980 else
1985 }
1986 }
1987 \f
1988 /* Set memoizing fields and bits of T (and its variants) for later
1989 use. */
1991 static void
1993 {
1994 /* Fix up variants (if any). */
1998 /* For a class w/o baseclasses, 'finish_struct' has set
1999 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2000 Similarly for a class whose base classes do not have vtables.
2001 When neither of these is true, we might have removed abstract
2002 virtuals (by providing a definition), added some (by declaring
2003 new ones), or redeclared ones from a base class. We need to
2004 recalculate what's really an abstract virtual at this point (by
2005 looking in the vtables). */
2008 /* If this type has a copy constructor or a destructor, force its
2009 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2010 nonzero. This will cause it to be passed by invisible reference
2011 and prevent it from being returned in a register. */
2014 {
2015 tree variants;
2018 {
2021 }
2022 }
2023 }
2025 /* Issue warnings about T having private constructors, but no friends,
2026 and so forth.
2028 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2029 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2030 non-private static member functions. */
2032 static void
2034 {
2039 /* If the class has friends, those entities might create and
2040 access instances, so we should not warn. */
2043 /* We will have warned when the template was declared; there's
2044 no need to warn on every instantiation. */
2046 /* There's no reason to even consider warning about this
2047 class. */
2050 /* We only issue one warning, if more than one applies, because
2051 otherwise, on code like:
2053 class A {
2054 // Oops - forgot `public:'
2055 A();
2056 A(const A&);
2057 ~A();
2058 };
2060 we warn several times about essentially the same problem. */
2062 /* Check to see if all (non-constructor, non-destructor) member
2063 functions are private. (Since there are no friends or
2064 non-private statics, we can't ever call any of the private member
2065 functions.) */
2070 /* We're not interested in compiler-generated methods; they don't
2073 {
2075 /* A non-private static member function is just like a
2076 friend; it can create and invoke private member
2077 functions, and be accessed without a class
2078 instance. */
2082 /* Keep searching for a static member function. */
2083 }
2088 {
2089 /* There are no non-private methods, and there's at least one
2090 private member function that isn't a constructor or
2091 destructor. (If all the private members are
2092 constructors/destructors we want to use the code below that
2093 issues error messages specifically referring to
2094 constructors/destructors.) */
2100 {
2103 }
2105 {
2109 }
2110 }
2112 /* Even if some of the member functions are non-private, the class
2113 won't be useful for much if all the constructors or destructors
2114 are private: such an object can never be created or destroyed. */
2117 {
2120 t);
2122 }
2124 /* Warn about classes that have private constructors and no friends. */
2126 /* Implicitly generated constructors are always public. */
2128 {
2132 /* If a non-template class does not define a copy
2133 constructor, one is defined for it, enabling it to avoid
2134 this warning. For a template class, this does not
2135 happen, and so we would normally get a warning on:
2137 template <class T> class C { private: C(); };
2139 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2140 complete non-template or fully instantiated classes have this
2141 flag set. */
2144 else
2150 /* Ideally, we wouldn't count any constructor that takes
2151 an argument of the class type as a parameter, because
2152 such things cannot be used to construct an instance of
2153 the class unless you already have one. */
2155 else
2159 {
2162 t);
2168 }
2169 }
2170 }
2172 /* Make BINFO's vtable have N entries, including RTTI entries,
2173 vbase and vcall offsets, etc. Set its type and call the back end
2174 to lay it out. */
2176 static void
2178 {
2179 tree atype;
2180 tree vtable;
2185 /* We may have to grow the vtable. */
2188 {
2192 }
2193 }
2195 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2196 have the same signature. */
2198 int
2200 {
2201 /* One destructor overrides another if they are the same kind of
2202 destructor. */
2206 /* But a non-destructor never overrides a destructor, nor vice
2207 versa, nor do different kinds of destructors override
2208 one-another. For example, a complete object destructor does not
2209 override a deleting destructor. */
2218 {
2226 }
2228 }
2230 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2231 subobject. */
2233 static bool
2235 {
2236 tree probe;
2239 {
2243 /* If we meet a virtual base, we can't follow the inheritance
2244 any more. See if the complete type of DERIVED contains
2245 such a virtual base. */
2248 }
2250 }
2253 /* The function for which we are trying to find a final overrider. */
2254 tree fn;
2255 /* The base class in which the function was declared. */
2256 tree declaring_base;
2257 /* The candidate overriders. */
2258 tree candidates;
2259 /* Path to most derived. */
2261 };
2263 /* Add the overrider along the current path to FFOD->CANDIDATES.
2264 Returns true if an overrider was found; false otherwise. */
2266 static bool
2270 {
2271 tree method;
2273 /* If BINFO is not the most derived type, try a more derived class.
2274 A definition there will overrider a definition here. */
2276 {
2277 depth--;
2281 }
2285 {
2288 /* Remove any candidates overridden by this new function. */
2290 {
2291 /* If *CANDIDATE overrides METHOD, then METHOD
2292 cannot override anything else on the list. */
2295 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2298 else
2300 }
2302 /* Add the new function. */
2305 }
2308 }
2310 /* Called from find_final_overrider via dfs_walk. */
2312 static tree
2314 {
2322 }
2324 static tree
2326 {
2331 }
2333 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2334 FN and whose TREE_VALUE is the binfo for the base where the
2335 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2336 DERIVED) is the base object in which FN is declared. */
2338 static tree
2340 {
2341 find_final_overrider_data ffod;
2343 /* Getting this right is a little tricky. This is valid:
2345 struct S { virtual void f (); };
2346 struct T { virtual void f (); };
2347 struct U : public S, public T { };
2349 even though calling `f' in `U' is ambiguous. But,
2351 struct R { virtual void f(); };
2352 struct S : virtual public R { virtual void f (); };
2353 struct T : virtual public R { virtual void f (); };
2354 struct U : public S, public T { };
2356 is not -- there's no way to decide whether to put `S::f' or
2357 `T::f' in the vtable for `R'.
2359 The solution is to look at all paths to BINFO. If we find
2360 different overriders along any two, then there is a problem. */
2364 /* Determine the depth of the hierarchy. */
2375 /* If there was no winner, issue an error message. */
2380 }
2382 /* Return the index of the vcall offset for FN when TYPE is used as a
2383 virtual base. */
2385 static tree
2387 {
2389 tree_pair_p p;
2397 /* There should always be an appropriate index. */
2399 }
2401 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2402 dominated by T. FN is the old function; VIRTUALS points to the
2403 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2404 of that entry in the list. */
2406 static void
2409 {
2410 tree b;
2411 tree overrider;
2412 tree delta;
2413 tree virtual_base;
2414 tree first_defn;
2420 /* Find the nearest primary base (possibly binfo itself) which defines
2421 this function; this is the class the caller will convert to when
2422 calling FN through BINFO. */
2424 {
2429 /* The nearest definition is from a lost primary. */
2432 }
2435 /* Find the final overrider. */
2438 {
2441 }
2444 /* Check for adjusting covariant return types. */
2452 /* If the overrider is invalid, don't even try. */
2454 {
2455 /* If FN is a covariant thunk, we must figure out the adjustment
2456 to the final base FN was converting to. As OVERRIDER_TARGET might
2457 also be converting to the return type of FN, we have to
2458 combine the two conversions here. */
2465 {
2469 }
2470 else
2474 /* Find the equivalent binfo within the return type of the
2475 overriding function. We will want the vbase offset from
2476 there. */
2478 over_return);
2481 {
2482 /* There was no existing virtual thunk (which takes
2483 precedence). So find the binfo of the base function's
2484 return type within the overriding function's return type.
2485 Fortunately we know the covariancy is valid (it
2486 has already been checked), so we can just iterate along
2487 the binfos, which have been chained in inheritance graph
2488 order. Of course it is lame that we have to repeat the
2489 search here anyway -- we should really be caching pieces
2490 of the vtable and avoiding this repeated work. */
2494 /* Find the base binfo within the overriding function's
2495 return type. We will always find a thunk_binfo, except
2496 when the covariancy is invalid (which we will have
2497 already diagnosed). */
2506 /* See if virtual inheritance is involved. */
2508 virtual_offset;
2515 {
2519 {
2520 /* We convert via virtual base. Adjust the fixed
2521 offset to be from there. */
2522 offset =
2526 }
2528 /* There was an existing fixed offset, this must be
2529 from the base just converted to, and the base the
2530 FN was thunking to. */
2532 else
2534 }
2535 }
2538 /* Replace the overriding function with a covariant thunk. We
2539 will emit the overriding function in its own slot as
2540 well. */
2543 }
2544 else
2548 /* If we need a covariant thunk, then we may need to adjust first_defn.
2549 The ABI specifies that the thunks emitted with a function are
2550 determined by which bases the function overrides, so we need to be
2551 sure that we're using a thunk for some overridden base; even if we
2552 know that the necessary this adjustment is zero, there may not be an
2553 appropriate zero-this-adjustment thunk for us to use since thunks for
2554 overriding virtual bases always use the vcall offset.
2556 Furthermore, just choosing any base that overrides this function isn't
2557 quite right, as this slot won't be used for calls through a type that
2558 puts a covariant thunk here. Calling the function through such a type
2559 will use a different slot, and that slot is the one that determines
2560 the thunk emitted for that base.
2562 So, keep looking until we find the base that we're really overriding
2563 in this slot: the nearest primary base that doesn't use a covariant
2564 thunk in this slot. */
2566 {
2568 /* We already know that the overrider needs a covariant thunk. */
2571 {
2578 }
2580 }
2582 /* Assume that we will produce a thunk that convert all the way to
2583 the final overrider, and not to an intermediate virtual base. */
2586 /* See if we can convert to an intermediate virtual base first, and then
2587 use the vcall offset located there to finish the conversion. */
2589 {
2590 /* If we find the final overrider, then we can stop
2591 walking. */
2596 /* If we find a virtual base, and we haven't yet found the
2597 overrider, then there is a virtual base between the
2598 declaring base (first_defn) and the final overrider. */
2600 {
2603 }
2604 }
2606 /* Compute the constant adjustment to the `this' pointer. The
2607 `this' pointer, when this function is called, will point at BINFO
2608 (or one of its primary bases, which are at the same offset). */
2610 /* The `this' pointer needs to be adjusted from the declaration to
2611 the nearest virtual base. */
2616 /* If the nearest definition is in a lost primary, we don't need an
2617 entry in our vtable. Except possibly in a constructor vtable,
2618 if we happen to get our primary back. In that case, the offset
2619 will be zero, as it will be a primary base. */
2621 else
2622 /* The `this' pointer needs to be adjusted from pointing to
2623 BINFO to pointing at the base where the final overrider
2624 appears. */
2635 else
2639 }
2641 /* Called from modify_all_vtables via dfs_walk. */
2643 static tree
2645 {
2647 tree virtuals;
2648 tree old_virtuals;
2652 /* A base without a vtable needs no modification, and its bases
2653 are uninteresting. */
2658 /* Don't do the primary vtable, if it's new. */
2662 /* There's no need to modify the vtable for a non-virtual primary
2663 base; we're not going to use that vtable anyhow. We do still
2664 need to do this for virtual primary bases, as they could become
2665 non-primary in a construction vtable. */
2670 /* Now, go through each of the virtual functions in the virtual
2671 function table for BINFO. Find the final overrider, and update
2672 the BINFO_VIRTUALS list appropriately. */
2675 virtuals;
2679 binfo,
2684 }
2686 /* Update all of the primary and secondary vtables for T. Create new
2687 vtables as required, and initialize their RTTI information. Each
2688 of the functions in VIRTUALS is declared in T and may override a
2689 virtual function from a base class; find and modify the appropriate
2690 entries to point to the overriding functions. Returns a list, in
2691 declaration order, of the virtual functions that are declared in T,
2692 but do not appear in the primary base class vtable, and which
2693 should therefore be appended to the end of the vtable for T. */
2695 static tree
2697 {
2701 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2705 /* Update all of the vtables. */
2708 /* Add virtual functions not already in our primary vtable. These
2709 will be both those introduced by this class, and those overridden
2710 from secondary bases. It does not include virtuals merely
2711 inherited from secondary bases. */
2713 {
2718 {
2719 /* We don't need to adjust the `this' pointer when
2720 calling this function. */
2724 /* This is a function not already in our vtable. Keep it. */
2726 }
2727 else
2728 /* We've already got an entry for this function. Skip it. */
2730 }
2733 }
2735 /* Get the base virtual function declarations in T that have the
2736 indicated NAME. */
2738 static void
2740 {
2743 /* Find virtual functions in T with the indicated NAME. */
2745 {
2749 {
2752 }
2753 }
2760 {
2763 }
2764 }
2766 /* If this declaration supersedes the declaration of
2767 a method declared virtual in the base class, then
2768 mark this field as being virtual as well. */
2770 void
2772 {
2775 /* In [temp.mem] we have:
2777 A specialization of a member function template does not
2778 override a virtual function from a base class. */
2785 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2786 the error_mark_node so that we know it is an overriding
2787 function. */
2788 {
2795 }
2798 {
2804 }
2809 }
2811 /* Warn about hidden virtual functions that are not overridden in t.
2812 We know that constructors and destructors don't apply. */
2814 static void
2816 {
2819 {
2827 tree base_binfo;
2828 tree binfo;
2831 /* Iterate through all of the base classes looking for possibly
2832 hidden functions. */
2835 {
2838 }
2840 /* If there are no functions to hide, continue. */
2844 /* Remove any overridden functions. */
2846 {
2850 {
2851 /* If the method from the base class has the same
2852 signature as the method from the derived class, it
2853 has been overridden. */
2858 }
2859 }
2861 /* Now give a warning for all base functions without overriders,
2862 as they are hidden. */
2863 tree base_fndecl;
2866 {
2867 /* Here we know it is a hider, and no overrider exists. */
2869 OPT_Woverloaded_virtual,
2873 }
2874 }
2875 }
2877 /* Recursive helper for finish_struct_anon. */
2879 static void
2881 {
2883 {
2884 /* We're generally only interested in entities the user
2885 declared, but we also find nested classes by noticing
2886 the TYPE_DECL that we create implicitly. You're
2887 allowed to put one anonymous union inside another,
2888 though, so we explicitly tolerate that. We use
2889 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2890 we also allow unnamed types used for defining fields. */
2899 {
2900 /* We already complained about static data members in
2901 finish_static_data_member_decl. */
2906 "only have public non-static data members"
2909 {
2912 {
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 {
3108 }
3109 }
3111 /* Create default constructors, assignment operators, and so forth for
3112 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3113 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3114 the class cannot have a default constructor, copy constructor
3115 taking a const reference argument, or an assignment operator taking
3116 a const reference, respectively. */
3118 static void
3122 {
3123 /* Destructor. */
3125 /* In general, we create destructors lazily. */
3134 /* [class.ctor]
3136 If there is no user-declared constructor for a class, a default
3137 constructor is implicitly declared. */
3139 {
3144 /* Don't force the declaration to get a hard answer; if the
3145 definition would have made the class non-literal, it will still be
3146 non-literal because of the base or member in question, and that
3147 gives a better diagnostic. */
3149 }
3151 /* [class.ctor]
3153 If a class definition does not explicitly declare a copy
3154 constructor, one is declared implicitly. */
3156 {
3162 }
3164 /* If there is no assignment operator, one will be created if and
3165 when it is needed. For now, just record whether or not the type
3166 of the parameter to the assignment operator will be a const or
3167 non-const reference. */
3169 {
3175 }
3177 /* We can't be lazy about declaring functions that might override
3178 a virtual function from a base class. */
3182 {
3186 {
3187 /* declare, then remove the decl */
3195 }
3196 else
3198 }
3199 }
3201 /* FIELD is a bit-field. We are finishing the processing for its
3202 enclosing type. Issue any appropriate messages and set appropriate
3203 flags. Returns false if an error has been diagnosed. */
3205 static bool
3207 {
3209 tree w;
3211 /* Extract the declared width of the bitfield, which has been
3212 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3215 /* Remove the bit-field width indicator so that the rest of the
3216 compiler does not treat that value as a qualifier. */
3219 /* Detect invalid bit-field type. */
3221 {
3224 }
3225 else
3226 {
3228 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3231 /* detect invalid field size. */
3237 {
3240 }
3242 {
3245 }
3247 {
3250 }
3260 {
3266 }
3267 }
3270 {
3274 }
3275 else
3276 {
3277 /* Non-bit-fields are aligned for their type. */
3281 }
3282 }
3284 /* FIELD is a non bit-field. We are finishing the processing for its
3285 enclosing type T. Issue any appropriate messages and set appropriate
3286 flags. */
3288 static bool
3290 tree t,
3293 {
3297 /* In C++98 an anonymous union cannot contain any fields which would change
3298 the settings of CANT_HAVE_CONST_CTOR and friends. */
3300 ;
3301 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3302 structs. So, we recurse through their fields here. */
3304 {
3309 cant_have_const_ctor,
3310 no_const_asn_ref);
3311 }
3312 /* Check members with class type for constructors, destructors,
3313 etc. */
3315 {
3316 /* Never let anything with uninheritable virtuals
3317 make it through without complaint. */
3321 {
3326 field);
3331 field);
3333 {
3337 }
3338 }
3339 else
3340 {
3353 }
3362 }
3367 /* `build_class_init_list' does not recognize
3368 non-FIELD_DECLs. */
3372 }
3374 /* Check the data members (both static and non-static), class-scoped
3375 typedefs, etc., appearing in the declaration of T. Issue
3376 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3377 declaration order) of access declarations; each TREE_VALUE in this
3378 list is a USING_DECL.
3380 In addition, set the following flags:
3382 EMPTY_P
3383 The class is empty, i.e., contains no non-static data members.
3385 CANT_HAVE_CONST_CTOR_P
3386 This class cannot have an implicitly generated copy constructor
3387 taking a const reference.
3389 CANT_HAVE_CONST_ASN_REF
3390 This class cannot have an implicitly generated assignment
3391 operator taking a const reference.
3393 All of these flags should be initialized before calling this
3394 function.
3396 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3397 fields can be added by adding to this chain. */
3399 static void
3403 {
3411 /* Assume there are no access declarations. */
3413 /* Assume this class has no pointer members. */
3415 /* Assume none of the members of this class have default
3416 initializations. */
3420 {
3428 {
3429 /* Save the access declarations for our caller. */
3432 }
3439 /* FIXME: We should fold in the checking from check_methods. */
3442 /* If we've gotten this far, it's a data member, possibly static,
3443 or an enumerator. */
3447 /* When this goes into scope, it will be a non-local reference. */
3451 {
3452 /* [class.union] (C++98)
3454 If a union contains a static data member, or a member of
3455 reference type, the program is ill-formed.
3457 In C++11 [class.union] says:
3458 If a union contains a non-static data member of reference type
3459 the program is ill-formed. */
3461 {
3465 }
3468 {
3472 }
3473 }
3475 /* Perform error checking that did not get done in
3476 grokdeclarator. */
3478 {
3482 }
3484 {
3488 }
3496 /* Now it can only be a FIELD_DECL. */
3501 /* If at least one non-static data member is non-literal, the whole
3502 class becomes non-literal. Per Core/1453, volatile non-static
3503 data members and base classes are also not allowed.
3504 Note: if the type is incomplete we will complain later on. */
3509 /* A standard-layout class is a class that:
3510 ...
3511 has the same access control (Clause 11) for all non-static data members,
3512 ... */
3519 /* If this is of reference type, check if it needs an init. */
3521 {
3527 {
3528 /* ARM $12.6.2: [A member initializer list] (or, for an
3529 aggregate, initialization by a brace-enclosed list) is the
3530 only way to initialize nonstatic const and reference
3531 members. */
3534 }
3535 }
3540 {
3542 {
3543 warning_at
3546 x);
3548 }
3552 }
3556 /* We don't treat zero-width bitfields as making a class
3557 non-empty. */
3558 ;
3559 else
3560 {
3561 /* The class is non-empty. */
3563 /* The class is not even nearly empty. */
3565 /* If one of the data members contains an empty class,
3566 so does T. */
3570 }
3572 /* This is used by -Weffc++ (see below). Warn only for pointers
3573 to members which might hold dynamic memory. So do not warn
3574 for pointers to functions or pointers to members. */
3580 {
3585 }
3591 {
3593 {
3597 }
3599 {
3603 }
3604 }
3607 /* DR 148 now allows pointers to members (which are POD themselves),
3608 to be allowed in POD structs. */
3617 /* We set DECL_C_BIT_FIELD in grokbitfield.
3618 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3623 {
3628 }
3630 /* Now that we've removed bit-field widths from DECL_INITIAL,
3631 anything left in DECL_INITIAL is an NSDMI that makes the class
3632 non-aggregate in C++11. */
3636 /* If any field is const, the structure type is pseudo-const. */
3638 {
3643 {
3644 /* ARM $12.6.2: [A member initializer list] (or, for an
3645 aggregate, initialization by a brace-enclosed list) is the
3646 only way to initialize nonstatic const and reference
3647 members. */
3650 }
3651 }
3652 /* A field that is pseudo-const makes the structure likewise. */
3654 {
3659 }
3661 /* Core issue 80: A nonstatic data member is required to have a
3662 different name from the class iff the class has a
3663 user-declared constructor. */
3668 }
3670 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3671 it should also define a copy constructor and an assignment operator to
3672 implement the correct copy semantic (deep vs shallow, etc.). As it is
3673 not feasible to check whether the constructors do allocate dynamic memory
3674 and store it within members, we approximate the warning like this:
3676 -- Warn only if there are members which are pointers
3677 -- Warn only if there is a non-trivial constructor (otherwise,
3678 there cannot be memory allocated).
3679 -- Warn only if there is a non-trivial destructor. We assume that the
3680 user at least implemented the cleanup correctly, and a destructor
3681 is needed to free dynamic memory.
3683 This seems enough for practical purposes. */
3685 && has_pointers
3689 {
3693 {
3698 }
3702 }
3704 /* Non-static data member initializers make the default constructor
3705 non-trivial. */
3707 {
3710 }
3712 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3716 /* Check anonymous struct/anonymous union fields. */
3719 /* We've built up the list of access declarations in reverse order.
3720 Fix that now. */
3722 }
3724 /* If TYPE is an empty class type, records its OFFSET in the table of
3725 OFFSETS. */
3727 static int
3729 {
3730 splay_tree_node n;
3735 /* Record the location of this empty object in OFFSETS. */
3743 type,
3747 }
3749 /* Returns nonzero if TYPE is an empty class type and there is
3750 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3752 static int
3754 {
3755 splay_tree_node n;
3756 tree t;
3761 /* Record the location of this empty object in OFFSETS. */
3771 }
3773 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3774 F for every subobject, passing it the type, offset, and table of
3775 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3776 be traversed.
3778 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3779 than MAX_OFFSET will not be walked.
3781 If F returns a nonzero value, the traversal ceases, and that value
3782 is returned. Otherwise, returns zero. */
3784 static int
3786 subobject_offset_fn f,
3787 tree offset,
3788 splay_tree offsets,
3789 tree max_offset,
3791 {
3795 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3796 stop. */
3804 {
3807 }
3810 {
3811 tree field;
3812 tree binfo;
3815 /* Avoid recursing into objects that are not interesting. */
3819 /* Record the location of TYPE. */
3824 /* Iterate through the direct base classes of TYPE. */
3828 {
3829 tree binfo_offset;
3834 tree orig_binfo;
3835 /* We cannot rely on BINFO_OFFSET being set for the base
3836 class yet, but the offsets for direct non-virtual
3837 bases can be calculated by going back to the TYPE. */
3840 offset,
3844 f,
3845 binfo_offset,
3846 offsets,
3847 max_offset,
3851 }
3854 {
3858 /* Iterate through the virtual base classes of TYPE. In G++
3859 3.2, we included virtual bases in the direct base class
3860 loop above, which results in incorrect results; the
3861 correct offsets for virtual bases are only known when
3862 working with the most derived type. */
3866 {
3868 f,
3870 offset,
3872 offsets,
3873 max_offset,
3877 }
3878 else
3879 {
3880 /* We still have to walk the primary base, if it is
3881 virtual. (If it is non-virtual, then it was walked
3882 above.) */
3888 {
3889 r = (walk_subobject_offsets
3894 }
3895 }
3896 }
3898 /* Iterate through the fields of TYPE. */
3903 {
3904 tree field_offset;
3909 f,
3911 offset,
3912 field_offset),
3913 offsets,
3914 max_offset,
3918 }
3919 }
3921 {
3924 tree index;
3926 /* Avoid recursing into objects that are not interesting. */
3929 || !domain
3933 /* Step through each of the elements in the array. */
3937 {
3939 f,
3940 offset,
3941 offsets,
3942 max_offset,
3948 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3949 there's no point in iterating through the remaining
3950 elements of the array. */
3953 }
3954 }
3957 }
3959 /* Record all of the empty subobjects of TYPE (either a type or a
3960 binfo). If IS_DATA_MEMBER is true, then a non-static data member
3961 is being placed at OFFSET; otherwise, it is a base class that is
3962 being placed at OFFSET. */
3964 static void
3966 tree offset,
3967 splay_tree offsets,
3969 {
3970 tree max_offset;
3971 /* If recording subobjects for a non-static data member or a
3972 non-empty base class , we do not need to record offsets beyond
3973 the size of the biggest empty class. Additional data members
3974 will go at the end of the class. Additional base classes will go
3975 either at offset zero (if empty, in which case they cannot
3976 overlap with offsets past the size of the biggest empty class) or
3977 at the end of the class.
3979 However, if we are placing an empty base class, then we must record
3980 all offsets, as either the empty class is at offset zero (where
3981 other empty classes might later be placed) or at the end of the
3982 class (where other objects might then be placed, so other empty
3983 subobjects might later overlap). */
3987 else
3991 }
3993 /* Returns nonzero if any of the empty subobjects of TYPE (located at
3994 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
3995 virtual bases of TYPE are examined. */
3997 static int
3999 tree offset,
4000 splay_tree offsets,
4002 {
4003 splay_tree_node max_node;
4005 /* Get the node in OFFSETS that indicates the maximum offset where
4006 an empty subobject is located. */
4008 /* If there aren't any empty subobjects, then there's no point in
4009 performing this check. */
4015 vbases_p);
4016 }
4018 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4019 non-static data member of the type indicated by RLI. BINFO is the
4020 binfo corresponding to the base subobject, OFFSETS maps offsets to
4021 types already located at those offsets. This function determines
4022 the position of the DECL. */
4024 static void
4026 tree decl,
4027 tree binfo,
4028 splay_tree offsets)
4029 {
4032 tree type;
4035 {
4036 /* For the purposes of determining layout conflicts, we want to
4037 use the class type of BINFO; TREE_TYPE (DECL) will be the
4038 CLASSTYPE_AS_BASE version, which does not contain entries for
4039 zero-sized bases. */
4042 }
4043 else
4044 {
4047 }
4049 /* Try to place the field. It may take more than one try if we have
4050 a hard time placing the field without putting two objects of the
4051 same type at the same address. */
4053 {
4056 /* Place this field. */
4060 /* We have to check to see whether or not there is already
4061 something of the same type at the offset we're about to use.
4062 For example, consider:
4064 struct S {};
4065 struct T : public S { int i; };
4066 struct U : public S, public T {};
4068 Here, we put S at offset zero in U. Then, we can't put T at
4069 offset zero -- its S component would be at the same address
4070 as the S we already allocated. So, we have to skip ahead.
4071 Since all data members, including those whose type is an
4072 empty class, have nonzero size, any overlap can happen only
4073 with a direct or indirect base-class -- it can't happen with
4074 a data member. */
4075 /* In a union, overlap is permitted; all members are placed at
4076 offset zero. */
4081 {
4082 /* Strip off the size allocated to this field. That puts us
4083 at the first place we could have put the field with
4084 proper alignment. */
4087 /* Bump up by the alignment required for the type. */
4088 rli->bitpos
4094 }
4097 {
4098 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4099 the offset wasn't aligned like a pointer when we started to
4100 layout this field, that affects its position. */
4103 {
4106 "alignment of %qD increased in -fabi-version=9 "
4108 else
4111 }
4113 }
4114 else
4115 /* There was no conflict. We're done laying out this field. */
4117 }
4119 /* Now that we know where it will be placed, update its
4120 BINFO_OFFSET. */
4122 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4123 this point because their BINFO_OFFSET is copied from another
4124 hierarchy. Therefore, we may not need to add the entire
4125 OFFSET. */
4131 }
4133 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4135 static int
4137 tree offset,
4139 {
4141 }
4143 /* Layout the empty base BINFO. EOC indicates the byte currently just
4144 past the end of the class, and should be correctly aligned for a
4145 class of the type indicated by BINFO; OFFSETS gives the offsets of
4146 the empty bases allocated so far. T is the most derived
4147 type. Return nonzero iff we added it at the end. */
4149 static bool
4152 {
4153 tree alignment;
4157 /* This routine should only be used for empty classes. */
4162 propagate_binfo_offsets
4166 /* This is an empty base class. We first try to put it at offset
4167 zero. */
4170 offsets,
4172 {
4173 /* That didn't work. Now, we move forward from the next
4174 available spot in the class. */
4178 {
4181 offsets,
4183 /* We finally found a spot where there's no overlap. */
4186 /* There's overlap here, too. Bump along to the next spot. */
4188 }
4189 }
4192 {
4197 }
4200 }
4202 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4203 fields at NEXT_FIELD, and return it. */
4205 static tree
4207 {
4208 /* Create the FIELD_DECL. */
4216 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4218 else
4219 {
4222 }
4228 /* Add the new FIELD_DECL to the list of fields for T. */
4234 }
4236 /* Layout the base given by BINFO in the class indicated by RLI.
4237 *BASE_ALIGN is a running maximum of the alignments of
4238 any base class. OFFSETS gives the location of empty base
4239 subobjects. T is the most derived type. Return nonzero if the new
4240 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4241 *NEXT_FIELD, unless BINFO is for an empty base class.
4243 Returns the location at which the next field should be inserted. */
4248 {
4253 /* This error is now reported in xref_tag, thus giving better
4254 location information. */
4257 /* Place the base class. */
4259 {
4260 tree decl;
4262 /* The containing class is non-empty because it has a non-empty
4263 base class. */
4266 /* Create the FIELD_DECL. */
4269 /* Try to place the field. It may take more than one try if we
4270 have a hard time placing the field without putting two
4271 objects of the same type at the same address. */
4273 }
4274 else
4275 {
4276 tree eoc;
4279 /* On some platforms (ARM), even empty classes will not be
4280 byte-aligned. */
4285 /* A nearly-empty class "has no proper base class that is empty,
4286 not morally virtual, and at an offset other than zero." */
4288 {
4291 /* The check above (used in G++ 3.2) is insufficient because
4292 an empty class placed at offset zero might itself have an
4293 empty base at a nonzero offset. */
4295 empty_base_at_nonzero_offset_p,
4296 size_zero_node,
4301 }
4303 /* We used to not create a FIELD_DECL for empty base classes because of
4304 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4305 be a problem anymore. We need them to handle initialization of C++17
4306 aggregate bases. */
4308 {
4313 }
4315 /* An empty virtual base causes a class to be non-empty
4316 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4317 here because that was already done when the virtual table
4318 pointer was created. */
4319 }
4321 /* Record the offsets of BINFO and its base subobjects. */
4324 offsets,
4328 }
4330 /* Layout all of the non-virtual base classes. Record empty
4331 subobjects in OFFSETS. T is the most derived type. Return nonzero
4332 if the type cannot be nearly empty. The fields created
4333 corresponding to the base classes will be inserted at
4334 *NEXT_FIELD. */
4336 static void
4339 {
4340 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4341 subobjects. */
4346 /* The primary base class is always allocated first. */
4351 /* Now allocate the rest of the bases. */
4353 {
4354 tree base_binfo;
4358 /* The primary base was already allocated above, so we don't
4359 need to allocate it again here. */
4363 /* Virtual bases are added at the end (a primary virtual base
4364 will have already been added). */
4370 }
4371 }
4373 /* Go through the TYPE_FIELDS of T issuing any appropriate
4374 diagnostics, figuring out which methods override which other
4375 methods, and so forth. */
4377 static void
4379 {
4382 {
4388 /* The name of the field is the original field name
4389 Save this in auxiliary field for later overloading. */
4391 {
4395 }
4397 /* All user-provided destructors are non-trivial.
4398 Constructors and assignment ops are handled in
4399 grok_special_member_properties. */
4406 "%<transaction_safe_dynamic%> may only be specified for "
4408 }
4409 }
4411 /* FN is a constructor or destructor. Clone the declaration to create
4412 a specialized in-charge or not-in-charge version, as indicated by
4413 NAME. */
4415 static tree
4417 {
4418 tree parms;
4419 tree clone;
4421 /* Copy the function. */
4423 /* Reset the function name. */
4425 /* Remember where this function came from. */
4427 /* Make it easy to find the CLONE given the FN. */
4431 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4433 {
4440 }
4441 else
4442 {
4443 // Clone constraints.
4447 }
4452 /* There's no pending inline data for this function. */
4456 /* The base-class destructor is not virtual. */
4458 {
4462 }
4468 /* If there was an in-charge parameter, drop it from the function
4469 type. */
4471 {
4474 /* Skip the `this' parameter. */
4476 /* Skip the in-charge parameter. */
4478 /* And the VTT parm, in a complete [cd]tor. */
4483 {
4484 /* If we're omitting inherited parms, that just leaves the VTT. */
4487 }
4491 parmtypes);
4497 }
4499 /* Copy the function parameters. */
4501 /* Remove the in-charge parameter. */
4503 {
4507 }
4508 /* And the VTT parm, in a complete [cd]tor. */
4510 {
4513 else
4514 {
4518 }
4519 }
4521 /* A base constructor inheriting from a virtual base doesn't get the
4522 arguments. */
4527 {
4530 }
4532 /* Create the RTL for this function. */
4537 }
4539 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4540 not invoke this function directly.
4542 For a non-thunk function, returns the address of the slot for storing
4543 the function it is a clone of. Otherwise returns NULL_TREE.
4545 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4546 cloned_function is unset. This is to support the separate
4547 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4548 on a template makes sense, but not the former. */
4550 tree *
4552 {
4560 {
4561 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4564 else
4565 #endif
4567 }
4572 else
4574 }
4576 /* Produce declarations for all appropriate clones of FN. If
4577 UPDATE_METHODS is true, the clones are added to the
4578 CLASSTYPE_MEMBER_VEC. */
4580 void
4582 {
4583 tree clone;
4585 /* Avoid inappropriate cloning. */
4591 {
4592 /* For each constructor, we need two variants: an in-charge version
4593 and a not-in-charge version. */
4600 }
4601 else
4602 {
4605 /* For each destructor, we need three variants: an in-charge
4606 version, a not-in-charge version, and an in-charge deleting
4607 version. We clone the deleting version first because that
4608 means it will go second on the TYPE_FIELDS list -- and that
4609 corresponds to the correct layout order in the virtual
4610 function table.
4612 For a non-virtual destructor, we do not build a deleting
4613 destructor. */
4615 {
4619 }
4626 }
4628 /* Note that this is an abstract function that is never emitted. */
4630 }
4632 /* DECL is an in charge constructor, which is being defined. This will
4633 have had an in class declaration, from whence clones were
4634 declared. An out-of-class definition can specify additional default
4635 arguments. As it is the clones that are involved in overload
4636 resolution, we must propagate the information from the DECL to its
4637 clones. */
4639 void
4641 {
4642 tree clone;
4646 {
4653 /* Skip the 'this' parameter. */
4669 {
4671 {
4675 }
4681 {
4682 /* A default parameter has been added. Adjust the
4683 clone's parameters. */
4687 {
4690 clone_parms);
4692 }
4695 tree type
4698 clone_parms);
4706 }
4707 }
4709 }
4710 }
4712 /* For each of the constructors and destructors in T, create an
4713 in-charge and not-in-charge variant. */
4715 static void
4717 {
4718 /* While constructors can be via a using declaration, at this point
4719 we no longer need to know that. */
4725 }
4727 /* Deduce noexcept for a destructor DTOR. */
4729 void
4731 {
4734 noexcept_deferred_spec);
4735 }
4737 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4738 of TYPE for virtual functions which FNDECL overrides. Return a
4739 mask of the tm attributes found therein. */
4741 static int
4743 {
4745 tree base_binfo;
4749 {
4757 {
4761 else
4764 }
4765 else
4767 }
4770 }
4772 /* Subroutine of set_method_tm_attributes. Handle the checks and
4773 inheritance for one virtual method FNDECL. */
4775 static void
4777 {
4778 tree tm_attr;
4783 /* If FNDECL doesn't actually override anything (i.e. T is the
4784 class that first declares FNDECL virtual), then we're done. */
4791 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4792 tm_pure must match exactly, otherwise no weakening of
4793 tm_safe > tm_callable > nothing. */
4794 /* ??? The tm_pure attribute didn't make the transition to the
4795 multivendor language spec. */
4797 {
4799 {
4802 }
4803 }
4804 /* If the overridden function is tm_pure, then FNDECL must be. */
4807 /* Look for base class combinations that cannot be satisfied. */
4809 {
4815 }
4816 /* If FNDECL did not declare an attribute, then inherit the most
4817 restrictive one. */
4819 {
4821 }
4822 /* Otherwise validate that we're not weaker than a function
4823 that is being overridden. */
4824 else
4825 {
4829 }
4832 err_override:
4836 }
4838 /* For each of the methods in T, propagate a class-level tm attribute. */
4840 static void
4842 {
4845 /* Don't bother collecting tm attributes if transactional memory
4846 support is not enabled. */
4850 /* Process virtual methods first, as they inherit directly from the
4851 base virtual function and also require validation of new attributes. */
4853 {
4854 tree vchain;
4857 {
4862 }
4863 }
4865 /* If the class doesn't have an attribute, nothing more to do. */
4870 /* Any method that does not yet have a tm attribute inherits
4871 the one from the class. */
4876 }
4878 /* Returns true if FN is a default constructor. */
4880 bool
4882 {
4885 }
4887 /* Returns true iff class T has a user-provided constructor that can be called
4888 with more than zero arguments. */
4890 bool
4892 {
4897 {
4904 }
4907 }
4909 /* Returns the defaulted constructor if T has one. Otherwise, returns
4910 NULL_TREE. */
4912 tree
4914 {
4919 {
4925 }
4928 }
4930 /* Returns true iff FN is a user-provided function, i.e. user-declared
4931 and not defaulted at its first declaration. */
4933 bool
4935 {
4938 else
4942 }
4944 /* Returns true iff class T has a user-provided constructor. */
4946 bool
4948 {
4960 }
4962 /* Returns true iff class T has a user-provided or explicit constructor. */
4964 bool
4966 {
4974 {
4978 }
4981 }
4983 /* Returns true iff class T has a non-user-provided (i.e. implicitly
4984 declared or explicitly defaulted in the class body) default
4985 constructor. */
4987 bool
4989 {
4996 {
5002 }
5005 }
5007 /* TYPE is being used as a virtual base, and has a non-trivial move
5008 assignment. Return true if this is due to there being a user-provided
5009 move assignment in TYPE or one of its subobjects; if there isn't, then
5010 multiple move assignment can't cause any harm. */
5012 bool
5014 {
5015 /* Does the type itself have a user-provided move assignment operator? */
5023 /* Do any of its bases? */
5025 tree base_binfo;
5030 /* Or non-static data members? */
5032 {
5037 }
5039 /* Seems not. */
5041 }
5043 /* If default-initialization leaves part of TYPE uninitialized, returns
5044 a DECL for the field or TYPE itself (DR 253). */
5046 tree
5048 {
5059 {
5063 }
5068 {
5072 }
5075 }
5077 /* Returns true iff for class T, a trivial synthesized default constructor
5078 would be constexpr. */
5080 bool
5082 {
5083 /* A defaulted trivial default constructor is constexpr
5084 if there is nothing to initialize. */
5087 }
5089 /* Returns true iff class T has a constexpr default constructor. */
5091 bool
5093 {
5094 tree fns;
5097 {
5098 /* The caller should have stripped an enclosing array. */
5101 }
5103 {
5106 /* Non-trivial, we need to check subobject constructors. */
5108 }
5111 }
5113 /* Returns true iff class T has a constexpr default constructor or has an
5114 implicitly declared default constructor that we can't tell if it's constexpr
5115 without forcing a lazy declaration (which might cause undesired
5116 instantiations). */
5118 bool
5120 {
5123 /* Assume it's constexpr. */
5126 }
5128 /* Returns true iff class TYPE has a virtual destructor. */
5130 bool
5132 {
5133 tree dtor;
5141 }
5143 /* Returns true iff T, a class, has a move-assignment or
5144 move-constructor. Does not lazily declare either.
5145 If USER_P is false, any move function will do. If it is true, the
5146 move function must be user-declared.
5148 Note that user-declared here is different from "user-provided",
5149 which doesn't include functions that are defaulted in the
5150 class. */
5152 bool
5154 {
5172 }
5174 /* If T, a class, has a user-provided copy constructor, copy assignment
5175 operator, or destructor, returns that function. Otherwise, null. */
5177 tree
5179 {
5182 {
5186 }
5192 {
5196 }
5199 {
5203 }
5206 }
5208 /* Nonzero if we need to build up a constructor call when initializing an
5209 object of this class, either because it has a user-declared constructor
5210 or because it doesn't have a default constructor (so we need to give an
5211 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5212 what you care about is whether or not an object can be produced by a
5213 constructor (e.g. so we don't set TREE_READONLY on const variables of
5214 such type); use this function when what you care about is whether or not
5215 to try to call a constructor to create an object. The latter case is
5216 the former plus some cases of constructors that cannot be called. */
5218 bool
5220 {
5221 tree inner;
5231 /* A user-declared constructor might be private, and a constructor might
5232 be trivial but deleted. */
5235 {
5241 }
5243 }
5245 /* Like type_build_ctor_call, but for destructors. */
5247 bool
5249 {
5250 tree inner;
5259 /* A user-declared destructor might be private, and a destructor might
5260 be trivial but deleted. */
5263 {
5269 }
5271 }
5273 /* Remove all zero-width bit-fields from T. */
5275 static void
5277 {
5282 {
5285 /* We should not be confused by the fact that grokbitfield
5286 temporarily sets the width of the bit field into
5287 DECL_BIT_FIELD_REPRESENTATIVE (*fieldsp).
5288 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5289 to that width. */
5293 else
5295 }
5296 }
5298 /* Returns TRUE iff we need a cookie when dynamically allocating an
5299 array whose elements have the indicated class TYPE. */
5301 static bool
5303 {
5304 tree fns;
5309 /* If there's a non-trivial destructor, we need a cookie. In order
5310 to iterate through the array calling the destructor for each
5311 element, we'll have to know how many elements there are. */
5315 /* If the usual deallocation function is a two-argument whose second
5316 argument is of type `size_t', then we have to pass the size of
5317 the array to the deallocation function, so we will need to store
5318 a cookie. */
5322 /* If there are no `operator []' members, or the lookup is
5323 ambiguous, then we don't need a cookie. */
5326 /* Loop through all of the functions. */
5328 {
5331 /* See if this function is a one-argument delete function. If
5332 it is, then it will be the usual deallocation function. */
5336 /* Do not consider this function if its second argument is an
5337 ellipsis. */
5340 /* Otherwise, if we have a two-argument function and the second
5341 argument is `size_t', it will be the usual deallocation
5342 function -- unless there is one-argument function, too. */
5346 }
5349 }
5351 /* Finish computing the `literal type' property of class type T.
5353 At this point, we have already processed base classes and
5354 non-static data members. We need to check whether the copy
5355 constructor is trivial, the destructor is trivial, and there
5356 is a trivial default constructor or at least one constexpr
5357 constructor other than the copy constructor. */
5359 static void
5361 {
5362 tree fn;
5374 /* C++14 DR 1684 removed this restriction. */
5382 {
5386 "enclosing class of %<constexpr%> non-static member "
5389 }
5390 }
5392 /* T is a non-literal type used in a context which requires a constant
5393 expression. Explain why it isn't literal. */
5395 void
5397 {
5407 /* Already explained. */
5413 " %qT is a closure type, which is only literal in "
5421 {
5423 " %q+T is not an aggregate, does not have a trivial "
5424 "default constructor, and has no %<constexpr%> constructor that "
5427 /* Note that we can't simply call locate_ctor because when the
5428 constructor is deleted it just returns NULL_TREE. */
5430 {
5437 {
5440 else
5443 }
5444 }
5445 }
5446 else
5447 {
5451 {
5454 {
5460 }
5461 }
5463 {
5464 tree ftype;
5469 {
5472 field);
5475 }
5479 }
5480 }
5481 }
5483 /* Check the validity of the bases and members declared in T. Add any
5484 implicitly-generated functions (like copy-constructors and
5485 assignment operators). Compute various flag bits (like
5486 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5487 level: i.e., independently of the ABI in use. */
5489 static void
5491 {
5492 /* Nonzero if the implicitly generated copy constructor should take
5493 a non-const reference argument. */
5495 /* Nonzero if the implicitly generated assignment operator
5496 should take a non-const reference argument. */
5498 tree access_decls;
5501 tree fn;
5503 /* By default, we use const reference arguments and generate default
5504 constructors. */
5508 /* Check all the base-classes and set FMEM members to point to arrays
5509 of potential interest. */
5512 /* Deduce noexcept on destructor. This needs to happen after we've set
5513 triviality flags appropriately for our bases. */
5518 /* Check all the method declarations. */
5521 /* Save the initial values of these flags which only indicate whether
5522 or not the class has user-provided functions. As we analyze the
5523 bases and members we can set these flags for other reasons. */
5527 /* Check all the data member declarations. We cannot call
5528 check_field_decls until we have called check_bases check_methods,
5529 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5530 being set appropriately. */
5535 /* A nearly-empty class has to be vptr-containing; a nearly empty
5536 class contains just a vptr. */
5540 /* Do some bookkeeping that will guide the generation of implicitly
5541 declared member functions. */
5544 /* We need to call a constructor for this class if it has a
5545 user-provided constructor, or if the default constructor is going
5546 to initialize the vptr. (This is not an if-and-only-if;
5547 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5548 themselves need constructing.) */
5551 /* [dcl.init.aggr]
5553 An aggregate is an array or a class with no user-provided
5554 constructors ... and no virtual functions.
5556 Again, other conditions for being an aggregate are checked
5557 elsewhere. */
5561 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5562 retain the old definition internally for ABI reasons. */
5571 /* If the only explicitly declared default constructor is user-provided,
5572 set TYPE_HAS_COMPLEX_DFLT. */
5578 /* Warn if a public base of a polymorphic type has an accessible
5579 non-virtual destructor. It is only now that we know the class is
5580 polymorphic. Although a polymorphic base will have a already
5581 been diagnosed during its definition, we warn on use too. */
5583 {
5586 tree base_binfo;
5590 {
5598 basetype);
5599 }
5600 }
5602 /* If the class has no user-declared constructor, but does have
5603 non-static const or reference data members that can never be
5604 initialized, issue a warning. */
5606 /* Classes with user-declared constructors are presumed to
5607 initialize these members. */
5609 /* Aggregates can be initialized with brace-enclosed
5610 initializers. */
5612 {
5613 tree field;
5616 {
5617 tree type;
5634 }
5635 }
5637 /* Synthesize any needed methods. */
5639 cant_have_const_ctor,
5640 no_const_asn_ref);
5642 /* Check defaulted declarations here so we have cant_have_const_ctor
5643 and don't need to worry about clones. */
5648 {
5651 {
5652 bool imp_const_p
5658 /* If the function is defaulted outside the class, we just
5659 give the synthesis error. */
5662 }
5664 }
5667 {
5668 /* "This class type is not an aggregate." */
5670 }
5672 /* Compute the 'literal type' property before we
5673 do anything with non-static member functions. */
5676 /* Create the in-charge and not-in-charge variants of constructors
5677 and destructors. */
5680 /* Process the using-declarations. */
5684 /* Figure out whether or not we will need a cookie when dynamically
5685 allocating an array of this type. */
5688 }
5690 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5691 accordingly. If a new vfield was created (because T doesn't have a
5692 primary base class), then the newly created field is returned. It
5693 is not added to the TYPE_FIELDS list; it is the caller's
5694 responsibility to do that. Accumulate declared virtual functions
5695 on VIRTUALS_P. */
5697 static tree
5699 {
5700 tree fn;
5702 /* Collect the virtual functions declared in T. */
5707 {
5716 }
5718 /* If we couldn't find an appropriate base class, create a new field
5719 here. Even if there weren't any new virtual functions, we might need a
5720 new virtual function table if we're supposed to include vptrs in
5721 all classes that need them. */
5723 {
5724 /* We build this decl with vtbl_ptr_type_node, which is a
5725 `vtable_entry_type*'. It might seem more precise to use
5726 `vtable_entry_type (*)[N]' where N is the number of virtual
5727 functions. However, that would require the vtable pointer in
5728 base classes to have a different type than the vtable pointer
5729 in derived classes. We could make that happen, but that
5730 still wouldn't solve all the problems. In particular, the
5731 type-based alias analysis code would decide that assignments
5732 to the base class vtable pointer can't alias assignments to
5733 the derived class vtable pointer, since they have different
5734 types. Thus, in a derived class destructor, where the base
5735 class constructor was inlined, we could generate bad code for
5736 setting up the vtable pointer.
5738 Therefore, we use one type for all vtable pointers. We still
5739 use a type-correct type; it's just doesn't indicate the array
5740 bounds. That's better than using `void*' or some such; it's
5741 cleaner, and it let's the alias analysis code know that these
5742 stores cannot alias stores to void*! */
5743 tree field;
5756 /* This class is non-empty. */
5760 }
5763 }
5765 /* Add OFFSET to all base types of BINFO which is a base in the
5766 hierarchy dominated by T.
5768 OFFSET, which is a type offset, is number of bytes. */
5770 static void
5772 {
5774 tree primary_binfo;
5775 tree base_binfo;
5777 /* Update BINFO's offset. */
5782 offset));
5784 /* Find the primary base class. */
5790 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5791 downwards. */
5793 {
5794 /* Don't do the primary base twice. */
5802 }
5803 }
5805 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5806 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5807 empty subobjects of T. */
5809 static void
5811 {
5812 tree vbase;
5819 /* Find the last field. The artificial fields created for virtual
5820 bases will go after the last extant field to date. */
5825 /* Go through the virtual bases, allocating space for each virtual
5826 base that is not already a primary base class. These are
5827 allocated in inheritance graph order. */
5829 {
5834 {
5835 /* This virtual base is not a primary base of any class in the
5836 hierarchy, so we have to add space for it. */
5839 }
5840 }
5841 }
5843 /* Returns the offset of the byte just past the end of the base class
5844 BINFO. */
5846 static tree
5848 {
5849 tree size;
5854 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5855 allocate some space for it. It cannot have virtual bases, so
5856 TYPE_SIZE_UNIT is fine. */
5858 else
5862 }
5864 /* Returns the offset of the byte just past the end of the base class
5865 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
5866 only non-virtual bases are included. */
5868 static tree
5870 {
5873 tree binfo;
5874 tree base_binfo;
5875 tree offset;
5880 {
5890 }
5895 {
5899 }
5902 }
5904 /* Warn about bases of T that are inaccessible because they are
5905 ambiguous. For example:
5907 struct S {};
5908 struct T : public S {};
5909 struct U : public S, public T {};
5911 Here, `(S*) new U' is not allowed because there are two `S'
5912 subobjects of U. */
5914 static void
5916 {
5919 tree basetype;
5920 tree binfo;
5921 tree base_binfo;
5923 /* If there are no repeated bases, nothing can be ambiguous. */
5927 /* Check direct bases. */
5930 {
5936 }
5938 /* Check for ambiguous virtual bases. */
5942 {
5948 }
5949 }
5951 /* Compare two INTEGER_CSTs K1 and K2. */
5953 static int
5955 {
5957 }
5959 /* Increase the size indicated in RLI to account for empty classes
5960 that are "off the end" of the class. */
5962 static void
5964 {
5965 tree eoc;
5966 tree rli_size;
5968 /* It might be the case that we grew the class to allocate a
5969 zero-sized base class. That won't be reflected in RLI, yet,
5970 because we are willing to overlay multiple bases at the same
5971 offset. However, now we need to make sure that RLI is big enough
5972 to reflect the entire class. */
5977 {
5978 /* The size should have been rounded to a whole byte. */
5981 rli->bitpos
5990 }
5991 }
5993 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
5994 BINFO_OFFSETs for all of the base-classes. Position the vtable
5995 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
5997 static void
5999 {
6000 tree non_static_data_members;
6001 tree field;
6002 tree vptr;
6003 record_layout_info rli;
6004 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6005 types that appear at that offset. */
6006 splay_tree empty_base_offsets;
6007 /* True if the last field laid out was a bit-field. */
6009 /* The location at which the next field should be inserted. */
6012 /* Keep track of the first non-static data member. */
6015 /* Start laying out the record. */
6018 /* Mark all the primary bases in the hierarchy. */
6021 /* Create a pointer to our virtual function table. */
6024 /* The vptr is always the first thing in the class. */
6026 {
6031 }
6032 else
6035 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6040 /* Layout the non-static data members. */
6042 {
6043 tree type;
6044 tree padding;
6046 /* We still pass things that aren't non-static data members to
6047 the back end, in case it wants to do something with them. */
6049 {
6051 /* If the static data member has incomplete type, keep track
6052 of it so that it can be completed later. (The handling
6053 of pending statics in finish_record_layout is
6054 insufficient; consider:
6056 struct S1;
6057 struct S2 { static S1 s1; };
6059 At this point, finish_record_layout will be called, but
6060 S1 is still incomplete.) */
6062 {
6064 /* The visibility of static data members is determined
6065 at their point of declaration, not their point of
6066 definition. */
6068 }
6070 }
6078 /* If this field is a bit-field whose width is greater than its
6079 type, then there are some special rules for allocating
6080 it. */
6083 {
6085 /* We must allocate the bits as if suitably aligned for the
6086 longest integer type that fits in this many bits. Then,
6087 we are supposed to use the left over bits as additional
6088 padding. */
6090 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6098 {
6100 /* Too big, so our current guess is what we want. */
6102 /* Not bigger than limit, ok */
6104 }
6106 /* Figure out how much additional padding is required. */
6108 /* In a union, the padding field must have the full width
6109 of the bit-field; all fields start at offset zero. */
6111 else
6118 /* An unnamed bitfield does not normally affect the
6119 alignment of the containing class on a target where
6120 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6121 make any exceptions for unnamed bitfields when the
6122 bitfields are longer than their types. Therefore, we
6123 temporarily give the field a name. */
6125 {
6128 }
6134 empty_base_offsets);
6137 /* Now that layout has been performed, set the size of the
6138 field to the size of its declared type; the rest of the
6139 field is effectively invisible. */
6141 /* We must also reset the DECL_MODE of the field. */
6143 }
6144 else
6146 empty_base_offsets);
6148 /* Remember the location of any empty classes in FIELD. */
6151 empty_base_offsets,
6154 /* If a bit-field does not immediately follow another bit-field,
6155 and yet it starts in the middle of a byte, we have failed to
6156 comply with the ABI. */
6159 /* The TREE_NO_WARNING flag gets set by Objective-C when
6160 laying out an Objective-C class. The ObjC ABI differs
6161 from the C++ ABI, and so we do not want a warning
6162 here. */
6164 && !last_field_was_bitfield
6167 bitsize_unit_node)))
6169 "offset of %qD is not ABI-compliant and may "
6172 /* The middle end uses the type of expressions to determine the
6173 possible range of expression values. In order to optimize
6174 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6175 must be made aware of the width of "i", via its type.
6177 Because C++ does not have integer types of arbitrary width,
6178 we must (for the purposes of the front end) convert from the
6179 type assigned here to the declared type of the bitfield
6180 whenever a bitfield expression is used as an rvalue.
6181 Similarly, when assigning a value to a bitfield, the value
6182 must be converted to the type given the bitfield here. */
6184 {
6189 {
6196 }
6197 }
6199 /* If we needed additional padding after this field, add it
6200 now. */
6202 {
6203 tree padding_field;
6206 FIELD_DECL,
6207 NULL_TREE,
6208 char_type_node);
6216 NULL_TREE,
6217 empty_base_offsets);
6218 }
6221 }
6224 {
6225 /* Make sure that we are on a byte boundary so that the size of
6226 the class without virtual bases will always be a round number
6227 of bytes. */
6230 }
6232 /* Delete all zero-width bit-fields from the list of fields. Now
6233 that the type is laid out they are no longer important. */
6237 {
6238 /* T needs a different layout as a base (eliding virtual bases
6239 or whatever). Create that version. */
6242 /* If the ABI version is not at least two, and the last
6243 field was a bit-field, RLI may not be on a byte
6244 boundary. In particular, rli_size_unit_so_far might
6245 indicate the last complete byte, while rli_size_so_far
6246 indicates the total number of bits used. Therefore,
6247 rli_size_so_far, rather than rli_size_unit_so_far, is
6248 used to compute TYPE_SIZE_UNIT. */
6256 eoc);
6266 /* Copy the non-static data members of T. This will include its
6267 direct non-virtual bases & vtable. */
6271 {
6275 }
6278 /* We use the base type for trivial assignments, and hence it
6279 needs a mode. */
6284 /* Record the base version of the type. */
6286 }
6287 else
6290 /* Every empty class contains an empty class. */
6294 /* Set the TYPE_DECL for this type to contain the right
6295 value for DECL_OFFSET, so that we can use it as part
6296 of a COMPONENT_REF for multiple inheritance. */
6299 /* Now fix up any virtual base class types that we left lying
6300 around. We must get these done before we try to lay out the
6301 virtual function table. As a side-effect, this will remove the
6302 base subobject fields. */
6305 /* Make sure that empty classes are reflected in RLI at this
6306 point. */
6309 /* Make sure not to create any structures with zero size. */
6315 /* If this is a non-POD, declaring it packed makes a difference to how it
6316 can be used as a field; don't let finalize_record_size undo it. */
6320 /* Let the back end lay out the type. */
6329 /* Warn about bases that can't be talked about due to ambiguity. */
6332 /* Now that we're done with layout, give the base fields the real types. */
6337 /* Clean up. */
6344 }
6346 /* Determine the "key method" for the class type indicated by TYPE,
6347 and set CLASSTYPE_KEY_METHOD accordingly. */
6349 void
6351 {
6352 tree method;
6359 /* The key method is the first non-pure virtual function that is not
6360 inline at the point of class definition. On some targets the
6361 key function may not be inline; those targets should not call
6362 this function until the end of the translation unit. */
6368 {
6371 }
6374 }
6376 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6377 class data member of non-zero size, otherwise false. */
6381 {
6389 {
6393 }
6396 }
6398 /* Used by find_flexarrays and related functions. */
6400 struct flexmems_t
6401 {
6402 /* The first flexible array member or non-zero array member found
6403 in the order of layout. */
6404 tree array;
6405 /* First non-static non-empty data member in the class or its bases. */
6406 tree first;
6407 /* The first non-static non-empty data member following either
6408 the flexible array member, if found, or the zero-length array member
6409 otherwise. AFTER[1] refers to the first such data member of a union
6410 of which the struct containing the flexible array member or zero-length
6411 array is a member, or NULL when no such union exists. This element is
6412 only used during searching, not for diagnosing problems. AFTER[0]
6413 refers to the first such data member that is not a member of such
6414 a union. */
6417 /* Refers to a struct (not union) in which the struct of which the flexible
6418 array is member is defined. Used to diagnose strictly (according to C)
6419 invalid uses of the latter structs. */
6420 tree enclosing;
6421 };
6423 /* Find either the first flexible array member or the first zero-length
6424 array, in that order of preference, among members of class T (but not
6425 its base classes), and set members of FMEM accordingly.
6426 BASE_P is true if T is a base class of another class.
6427 PUN is set to the outermost union in which the flexible array member
6428 (or zero-length array) is defined if one such union exists, otherwise
6429 to NULL.
6430 Similarly, PSTR is set to a data member of the outermost struct of
6431 which the flexible array is a member if one such struct exists,
6432 otherwise to NULL. */
6434 static void
6438 {
6439 /* Set the "pointer" to the outermost enclosing union if not set
6440 yet and maintain it for the remainder of the recursion. */
6445 {
6449 /* Is FLD a typedef for an anonymous struct? */
6451 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6452 handled elsewhere so that errors like the following are detected
6453 as well:
6454 typedef struct { int i, a[], j; } S; // bug c++/72753
6455 S s [2]; // bug c++/68489
6456 */
6461 {
6462 /* Check the nested unnamed type referenced via a typedef
6463 independently of FMEM (since it's not a data member of
6464 the enclosing class). */
6467 }
6469 /* Skip anything that's GCC-generated or not a (non-static) data
6470 member. */
6474 /* Type of the member. */
6479 /* Determine the type of the array element or object referenced
6480 by the member so that it can be checked for flexible array
6481 members if it hasn't been yet. */
6488 {
6490 {
6491 /* Once the member after the flexible array has been found
6492 we're done. */
6495 }
6498 {
6499 /* Descend into the non-static member struct or union and try
6500 to find a flexible array member or zero-length array among
6501 its members. This is only necessary for anonymous types
6502 and types in whose context the current type T has not been
6503 defined (the latter must not be checked again because they
6504 are already in the process of being checked by one of the
6505 recursive calls). */
6510 /* If this member isn't anonymous and a prior non-flexible array
6511 member has been seen in one of the enclosing structs, clear
6512 the FIRST member since it doesn't contribute to the flexible
6513 array struct's members. */
6524 {
6525 /* Restore the FIRST member reset above if no flexible
6526 array member has been found in this member's struct. */
6528 }
6530 /* If the member struct contains the first flexible array
6531 member, or if this member is a base class, continue to
6532 the next member and avoid setting the FMEM->NEXT pointer
6533 to point to it. */
6536 }
6537 }
6540 {
6541 /* Remember the first non-static data member. */
6545 /* Remember the first non-static data member after the flexible
6546 array member, if one has been found, or the zero-length array
6547 if it has been found. */
6550 }
6552 /* Skip non-arrays. */
6556 /* Determine the upper bound of the array if it has one. */
6558 {
6560 {
6561 /* Make a record of the zero-length array if either one
6562 such field or a flexible array member has been seen to
6563 handle the pathological and unlikely case of multiple
6564 such members. */
6567 }
6569 {
6570 /* Remember the first zero-length array unless a flexible array
6571 member has already been seen. */
6574 }
6575 }
6576 else
6577 {
6578 /* Flexible array members have no upper bound. */
6580 {
6582 {
6583 /* Replace the zero-length array if it's been stored and
6584 reset the after pointer. */
6588 }
6590 /* Make a record of another flexible array member. */
6592 }
6593 else
6594 {
6597 }
6598 }
6599 }
6600 }
6602 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6603 a flexible array member (or the zero-length array extension). */
6605 static void
6607 {
6619 }
6621 /* Issue diagnostics for invalid flexible array members or zero-length
6622 arrays that are not the last elements of the containing class or its
6623 base classes or that are its sole members. */
6625 static void
6627 {
6632 {
6635 }
6637 /* Has a diagnostic been issued? */
6643 {
6650 {
6654 {
6657 }
6658 }
6659 }
6660 else
6661 {
6668 {
6674 /* In the unlikely event that the member following the flexible
6675 array member is declared in a different class, or the member
6676 overlaps another member of a common union, point to it.
6677 Otherwise it should be obvious. */
6681 {
6686 }
6687 }
6688 }
6692 }
6695 /* Recursively check to make sure that any flexible array or zero-length
6696 array members of class T or its bases are valid (i.e., not the sole
6697 non-static data member of T and, if one exists, that it is the last
6698 non-static data member of T and its base classes. FMEM is expected
6699 to be initially null and is used internally by recursive calls to
6700 the function. Issue the appropriate diagnostics for the array member
6701 that fails the checks. */
6703 static void
6706 {
6707 /* Initialize the result of a search for flexible array and zero-length
6708 array members. Avoid doing any work if the most interesting FMEM data
6709 have already been populated. */
6718 /* Recursively check the primary base class first. */
6720 {
6723 }
6725 /* Recursively check the base classes. */
6728 {
6731 /* The primary base class was already checked above. */
6735 /* Virtual base classes are at the end. */
6739 /* Check the base class. */
6741 }
6744 {
6745 /* Check virtual base classes only once per derived class.
6746 I.e., this check is not performed recursively for base
6747 classes. */
6749 tree base_binfo;
6753 {
6754 /* Check the virtual base class. */
6758 }
6759 }
6761 /* Is the type unnamed (and therefore a member of it potentially
6762 an anonymous struct or union)? */
6765 /* Search the members of the current (possibly derived) class, skipping
6766 unnamed structs and unions since those could be anonymous. */
6771 {
6772 /* Issue diagnostics for invalid flexible and zero-length array
6773 members found in base classes or among the members of the current
6774 class. Ignore anonymous structs and unions whose members are
6775 considered to be members of the enclosing class and thus will
6776 be diagnosed when checking it. */
6778 }
6779 }
6781 /* Perform processing required when the definition of T (a class type)
6782 is complete. Diagnose invalid definitions of flexible array members
6783 and zero-size arrays. */
6785 void
6787 {
6788 tree x;
6789 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6793 {
6798 }
6800 /* If this type was previously laid out as a forward reference,
6801 make sure we lay it out again. */
6805 /* Make assumptions about the class; we'll reset the flags if
6806 necessary. */
6812 /* Do end-of-class semantic processing: checking the validity of the
6813 bases and members and add implicitly generated methods. */
6816 /* Find the key method. */
6818 {
6819 /* The Itanium C++ ABI permits the key method to be chosen when
6820 the class is defined -- even though the key method so
6821 selected may later turn out to be an inline function. On
6822 some systems (such as ARM Symbian OS) the key method cannot
6823 be determined until the end of the translation unit. On such
6824 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6825 will cause the class to be added to KEYED_CLASSES. Then, in
6826 finish_file we will determine the key method. */
6830 /* If a polymorphic class has no key method, we may emit the vtable
6831 in every translation unit where the class definition appears. If
6832 we're devirtualizing, we can look into the vtable even if we
6833 aren't emitting it. */
6836 }
6838 /* Layout the class itself. */
6840 /* COMPLETE_TYPE_P is now true. */
6844 /* With the layout complete, check for flexible array members and
6845 zero-length arrays that might overlap other members in the final
6846 layout. */
6851 /* If necessary, create the primary vtable for this class. */
6853 {
6854 /* We must enter these virtuals into the table. */
6858 /* Here we know enough to change the type of our virtual
6859 function table, but we will wait until later this function. */
6862 /* If we're warning about ABI tags, check the types of the new
6863 virtual functions. */
6867 }
6870 {
6872 tree fn;
6879 /* Add entries for virtual functions introduced by this class. */
6883 /* Set DECL_VINDEX for all functions declared in this class. */
6885 fn;
6887 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6889 {
6893 /* A thunk. We should never be calling this entry directly
6894 from this vtable -- we'd use the entry for the non
6895 thunk base function. */
6899 }
6900 }
6908 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
6909 for any static member objects of the type we're working on. */
6918 /* Complain if one of the field types requires lower visibility. */
6921 /* Make the rtl for any new vtables we have created, and unmark
6922 the base types we marked. */
6925 /* Build the VTT for T. */
6932 "%q#T has virtual functions and accessible"
6940 /* Class layout, assignment of virtual table slots, etc., is now
6941 complete. Give the back end a chance to tweak the visibility of
6942 the class or perform any other required target modifications. */
6952 /* Finish debugging output for this type. */
6956 {
6959 {
6962 }
6964 {
6967 else
6968 {
6971 }
6973 }
6975 {
6977 "the type of the first field has a different ABI from the "
6980 }
6981 }
6982 }
6984 /* When T was built up, the member declarations were added in reverse
6985 order. Rearrange them to declaration order. */
6987 void
6989 {
6990 tree next;
6991 tree prev;
6992 tree x;
6994 /* The following lists are all in reverse order. Put them in
6995 declaration order now. */
6998 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
6999 order, so we can't just use nreverse. Due to stat_hack
7000 chicanery in finish_member_declaration. */
7005 {
7009 }
7012 {
7015 }
7016 }
7018 tree
7020 {
7023 /* Now that we've got all the field declarations, reverse everything
7024 as necessary. */
7030 /* Nadger the current location so that diagnostics point to the start of
7031 the struct, not the end. */
7035 {
7036 tree x;
7038 /* We need to add the target functions of USING_DECLS, so that
7039 they can be found when the using declaration is not
7040 instantiated yet. */
7043 {
7048 }
7054 /* COMPLETE_TYPE_P is now true. */
7058 /* We need to emit an error message if this type was used as a parameter
7059 and it is an abstract type, even if it is a template. We construct
7060 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7061 account and we call complete_vars with this type, which will check
7062 the PARM_DECLS. Note that while the type is being defined,
7063 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7064 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7071 /* Remember current #pragma pack value. */
7074 /* Fix up any variants we've already built. */
7076 {
7080 }
7081 }
7082 else
7084 /* COMPLETE_TYPE_P is now true. */
7089 {
7090 /* People keep complaining that the compiler crashes on an invalid
7091 definition of initializer_list, so I guess we should explicitly
7092 reject it. What the compiler internals care about is that it's a
7093 template and has a pointer field followed by size_type field. */
7096 {
7099 {
7103 }
7104 }
7108 }
7116 else
7120 /* Lambdas are defined by the LAMBDA_EXPR. */
7125 }
7126 \f
7127 /* Hash table to avoid endless recursion when handling references. */
7130 /* Return the dynamic type of INSTANCE, if known.
7131 Used to determine whether the virtual function table is needed
7132 or not.
7134 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7135 of our knowledge of its type. *NONNULL should be initialized
7136 before this function is called. */
7138 static tree
7140 {
7141 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7144 {
7148 else
7152 /* This is a call to a constructor, hence it's never zero. */
7155 {
7159 }
7163 /* This is a call to a constructor, hence it's never zero. */
7165 {
7169 }
7178 /* Propagate nonnull. */
7183 CASE_CONVERT:
7189 {
7190 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7191 with a real object -- given &p->f, p can still be null. */
7193 /* ??? Probably should check DECL_WEAK here. */
7196 }
7200 /* If this component is really a base class reference, then the field
7201 itself isn't definitive. */
7210 {
7214 }
7215 /* fall through. */
7220 {
7224 }
7226 {
7230 /* if we're in a ctor or dtor, we know our type. If
7231 current_class_ptr is set but we aren't in a function, we're in
7232 an NSDMI (and therefore a constructor). */
7237 {
7241 }
7242 }
7244 {
7245 /* We only need one hash table because it is always left empty. */
7247 fixed_type_or_null_ref_ht
7250 /* Reference variables should be references to objects. */
7254 /* Enter the INSTANCE in a table to prevent recursion; a
7255 variable's initializer may refer to the variable
7256 itself. */
7261 {
7262 tree type;
7271 }
7272 }
7277 }
7278 #undef RECUR
7279 }
7281 /* Return nonzero if the dynamic type of INSTANCE is known, and
7282 equivalent to the static type. We also handle the case where
7283 INSTANCE is really a pointer. Return negative if this is a
7284 ctor/dtor. There the dynamic type is known, but this might not be
7285 the most derived base of the original object, and hence virtual
7286 bases may not be laid out according to this type.
7288 Used to determine whether the virtual function table is needed
7289 or not.
7291 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7292 of our knowledge of its type. *NONNULL should be initialized
7293 before this function is called. */
7295 int
7297 {
7300 tree fixed;
7302 /* processing_template_decl can be false in a template if we're in
7303 instantiate_non_dependent_expr, but we still want to suppress
7304 this check. */
7306 {
7307 /* In a template we only care about the type of the result. */
7311 }
7321 }
7323 \f
7324 void
7326 {
7329 current_class_stack
7337 }
7339 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7341 static void
7343 {
7344 tree type;
7346 /* We are re-entering the same class we just left, so we don't
7347 have to search the whole inheritance matrix to find all the
7348 decls to bind again. Instead, we install the cached
7349 class_shadowed list and walk through it binding names. */
7352 /* Restore IDENTIFIER_TYPE_VALUE. */
7354 type;
7357 }
7359 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7360 appropriate for TYPE.
7362 So that we may avoid calls to lookup_name, we cache the _TYPE
7363 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7365 For multiple inheritance, we perform a two-pass depth-first search
7366 of the type lattice. */
7368 void
7370 {
7371 class_stack_node_t csn;
7375 /* Make sure there is enough room for the new entry on the stack. */
7377 {
7379 current_class_stack
7381 current_class_stack_size);
7382 }
7384 /* Insert a new entry on the class stack. */
7391 current_class_depth++;
7393 /* Now set up the new type. */
7399 /* By default, things in classes are private, while things in
7400 structures or unions are public. */
7402 ? access_private_node
7408 {
7409 /* Forcibly remove any old class remnants. */
7411 }
7417 else
7419 }
7421 /* When we exit a toplevel class scope, we save its binding level so
7422 that we can restore it quickly. Here, we've entered some other
7423 class, so we must invalidate our cache. */
7425 void
7427 {
7429 }
7431 /* Get out of the current class scope. If we were in a class scope
7432 previously, that is the one popped to. */
7434 void
7436 {
7439 current_class_depth--;
7445 }
7447 /* Mark the top of the class stack as hidden. */
7449 void
7451 {
7454 }
7456 /* Mark the top of the class stack as un-hidden. */
7458 void
7460 {
7463 }
7465 /* If the class type currently being defined is either T or
7466 a nested type of T, returns the type from the current_class_stack,
7467 which might be equivalent to but not equal to T in case of
7468 constrained partial specializations. */
7470 tree
7472 {
7480 /* We start looking from 1 because entry 0 is from global scope,
7481 and has no type. */
7483 {
7484 tree c;
7487 else
7488 {
7492 }
7497 }
7499 }
7501 /* If either current_class_type or one of its enclosing classes are derived
7502 from T, return the appropriate type. Used to determine how we found
7503 something via unqualified lookup. */
7505 tree
7507 {
7510 /* The bases of a dependent type are unknown. */
7521 {
7526 }
7529 }
7531 /* Return the outermost enclosing class type that is still open, or
7532 NULL_TREE. */
7534 tree
7536 {
7543 {
7550 }
7552 }
7554 /* Returns the innermost class type which is not a lambda closure type. */
7556 tree
7558 {
7563 }
7565 /* When entering a class scope, all enclosing class scopes' names with
7566 static meaning (static variables, static functions, types and
7567 enumerators) have to be visible. This recursive function calls
7568 pushclass for all enclosing class contexts until global or a local
7569 scope is reached. TYPE is the enclosed class. */
7571 void
7573 {
7574 /* A namespace might be passed in error cases, like A::B:C. */
7582 }
7584 /* Undoes a push_nested_class call. */
7586 void
7588 {
7594 }
7596 /* Returns the number of extern "LANG" blocks we are nested within. */
7598 int
7600 {
7602 }
7604 /* Set global variables CURRENT_LANG_NAME to appropriate value
7605 so that behavior of name-mangling machinery is correct. */
7607 void
7609 {
7616 else
7618 }
7620 /* Get out of the current language scope. */
7622 void
7624 {
7626 }
7627 \f
7628 /* Type instantiation routines. */
7630 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7631 matches the TARGET_TYPE. If there is no satisfactory match, return
7632 error_mark_node, and issue an error & warning messages under
7633 control of FLAGS. Permit pointers to member function if FLAGS
7634 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7635 a template-id, and EXPLICIT_TARGS are the explicitly provided
7636 template arguments.
7638 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7639 is the base path used to reference those member functions. If
7640 the address is resolved to a member function, access checks will be
7641 performed and errors issued if appropriate. */
7643 static tree
7645 tree overload,
7646 tsubst_flags_t complain,
7648 tree explicit_targs,
7649 tree access_path)
7650 {
7651 /* Here's what the standard says:
7653 [over.over]
7655 If the name is a function template, template argument deduction
7656 is done, and if the argument deduction succeeds, the deduced
7657 arguments are used to generate a single template function, which
7658 is added to the set of overloaded functions considered.
7660 Non-member functions and static member functions match targets of
7661 type "pointer-to-function" or "reference-to-function." Nonstatic
7662 member functions match targets of type "pointer-to-member
7663 function;" the function type of the pointer to member is used to
7664 select the member function from the set of overloaded member
7665 functions. If a nonstatic member function is selected, the
7666 reference to the overloaded function name is required to have the
7667 form of a pointer to member as described in 5.3.1.
7669 If more than one function is selected, any template functions in
7670 the set are eliminated if the set also contains a non-template
7671 function, and any given template function is eliminated if the
7672 set contains a second template function that is more specialized
7673 than the first according to the partial ordering rules 14.5.5.2.
7674 After such eliminations, if any, there shall remain exactly one
7675 selected function. */
7678 /* We store the matches in a TREE_LIST rooted here. The functions
7679 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7680 interoperability with most_specialized_instantiation. */
7682 tree fn;
7683 tree target_fn_type;
7685 /* By the time we get here, we should be seeing only real
7686 pointer-to-member types, not the internal POINTER_TYPE to
7687 METHOD_TYPE representation. */
7693 /* Check that the TARGET_TYPE is reasonable. */
7698 /* This is OK, too. */
7701 /* This is OK, too. This comes from a conversion to reference
7702 type. */
7704 else
7705 {
7711 }
7713 /* Non-member functions and static member functions match targets of type
7714 "pointer-to-function" or "reference-to-function." Nonstatic member
7715 functions match targets of type "pointer-to-member-function;" the
7716 function type of the pointer to member is used to select the member
7717 function from the set of overloaded member functions.
7719 So figure out the FUNCTION_TYPE that we want to match against. */
7722 /* If we can find a non-template function that matches, we can just
7723 use it. There's no point in generating template instantiations
7724 if we're just going to throw them out anyhow. But, of course, we
7725 can only do this when we don't *need* a template function. */
7728 {
7732 /* We're not looking for templates just yet. */
7736 /* We're looking for a non-static member, and this isn't
7737 one, or vice versa. */
7740 /* In C++17 we need the noexcept-qualifier to compare types. */
7745 /* See if there's a match. */
7750 }
7752 /* Now, if we've already got a match (or matches), there's no need
7753 to proceed to the template functions. But, if we don't have a
7754 match we need to look at them, too. */
7756 {
7757 tree target_arg_types;
7758 tree target_ret_type;
7761 tree arg;
7775 {
7777 tree instantiation;
7778 tree targs;
7781 /* We're only looking for templates. */
7786 /* We're not looking for a non-static member, and this is
7787 one, or vice versa. */
7792 /* If the template has a deduced return type, don't expose it to
7793 template argument deduction. */
7797 /* Try to do argument deduction. */
7804 /* Instantiation failed. */
7807 /* Constraints must be satisfied. This is done before
7808 return type deduction since that instantiates the
7809 function. */
7813 /* And now force instantiation to do return type deduction. */
7815 {
7821 }
7823 /* In C++17 we need the noexcept-qualifier to compare types. */
7827 /* See if there's a match. */
7832 }
7834 /* Now, remove all but the most specialized of the matches. */
7836 {
7841 NULL_TREE,
7842 NULL_TREE);
7843 }
7844 }
7846 /* Now we should have exactly one function in MATCHES. */
7848 {
7849 /* There were *no* matches. */
7851 {
7856 }
7858 }
7860 {
7861 /* There were too many matches. First check if they're all
7862 the same function. */
7867 /* For multi-versioned functions, more than one match is just fine and
7868 decls_match will return false as they are different. */
7876 {
7878 {
7882 /* Since print_candidates expects the functions in the
7883 TREE_VALUE slot, we flip them here. */
7888 }
7891 }
7892 }
7894 /* Good, exactly one match. Now, convert it to the correct type. */
7899 {
7907 {
7910 }
7911 }
7913 /* If a pointer to a function that is multi-versioned is requested, the
7914 pointer to the dispatcher function is returned instead. This works
7915 well because indirectly calling the function will dispatch the right
7916 function version at run-time. */
7918 {
7922 /* Mark all the versions corresponding to the dispatcher as used. */
7925 }
7927 /* If we're doing overload resolution purely for the purpose of
7928 determining conversion sequences, we should not consider the
7929 function used. If this conversion sequence is selected, the
7930 function will be marked as used at this point. */
7932 {
7933 /* Make =delete work with SFINAE. */
7938 }
7940 /* We could not check access to member functions when this
7941 expression was originally created since we did not know at that
7942 time to which function the expression referred. */
7944 {
7947 }
7951 else
7952 {
7953 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
7954 will mark the function as addressed, but here we must do it
7955 explicitly. */
7959 }
7960 }
7962 /* This function will instantiate the type of the expression given in
7963 RHS to match the type of LHSTYPE. If errors exist, then return
7964 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
7965 we complain on errors. If we are not complaining, never modify rhs,
7966 as overload resolution wants to try many possible instantiations, in
7967 the hope that at least one will work.
7969 For non-recursive calls, LHSTYPE should be a function, pointer to
7970 function, or a pointer to member function. */
7972 tree
7974 {
7981 {
7985 }
7988 {
7997 /* Microsoft allows `A::f' to be resolved to a
7998 pointer-to-member. */
7999 ;
8000 else
8001 {
8006 }
8007 }
8009 /* If we instantiate a template, and it is a A ?: C expression
8010 with omitted B, look through the SAVE_EXPR. */
8015 {
8018 }
8020 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
8021 deduce any type information. */
8023 {
8027 }
8029 /* There are only a few kinds of expressions that may have a type
8030 dependent on overload resolution. */
8036 /* This should really only be used when attempting to distinguish
8037 what sort of a pointer to function we have. For now, any
8038 arithmetic operation which is not supported on pointers
8039 is rejected as an error. */
8042 {
8044 {
8050 /* Do not lose object's side effects. */
8054 }
8061 /* This can happen if we are forming a pointer-to-member for a
8062 member template. */
8065 /* Fall through. */
8068 {
8072 return
8076 }
8080 return
8084 access_path);
8087 {
8092 }
8099 }
8101 }
8102 \f
8103 /* Return the name of the virtual function pointer field
8104 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8105 this may have to look back through base types to find the
8106 ultimate field name. (For single inheritance, these could
8107 all be the same name. Who knows for multiple inheritance). */
8109 static tree
8111 {
8117 {
8123 }
8131 }
8133 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8134 according to [class]:
8135 The class-name is also inserted
8136 into the scope of the class itself. For purposes of access checking,
8137 the inserted class name is treated as if it were a public member name. */
8139 void
8141 {
8158 }
8160 /* Returns 1 if TYPE contains only padding bytes. */
8162 int
8164 {
8172 }
8174 /* Returns true if TYPE contains no actual data, just various
8175 possible combinations of empty classes and possibly a vptr. */
8177 bool
8179 {
8181 {
8182 tree field;
8183 tree binfo;
8184 tree base_binfo;
8187 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8188 out, but we'd like to be able to check this before then. */
8199 /* An unnamed bit-field is not a data member. */
8204 }
8209 }
8211 /* Note that NAME was looked up while the current class was being
8212 defined and that the result of that lookup was DECL. */
8214 void
8216 {
8217 splay_tree names_used;
8219 /* If we're not defining a class, there's nothing to do. */
8225 /* If there's already a binding for this NAME, then we don't have
8226 anything to worry about. */
8239 }
8241 /* Note that NAME was declared (as DECL) in the current class. Check
8242 to see that the declaration is valid. */
8244 void
8246 {
8247 splay_tree names_used;
8248 splay_tree_node n;
8250 /* Look to see if we ever used this name. */
8251 names_used
8255 /* The C language allows members to be declared with a type of the same
8256 name, and the C++ standard says this diagnostic is not required. So
8257 allow it in extern "C" blocks unless predantic is specified.
8258 Allow it in all cases if -ms-extensions is specified. */
8264 {
8265 /* [basic.scope.class]
8267 A name N used in a class S shall refer to the same declaration
8268 in its context and when re-evaluated in the completed scope of
8269 S. */
8274 }
8275 }
8277 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8278 Secondary vtables are merged with primary vtables; this function
8279 will return the VAR_DECL for the primary vtable. */
8281 tree
8283 {
8284 tree decl;
8288 {
8291 }
8295 }
8298 /* Returns the binfo for the primary base of BINFO. If the resulting
8299 BINFO is a virtual base, and it is inherited elsewhere in the
8300 hierarchy, then the returned binfo might not be the primary base of
8301 BINFO in the complete object. Check BINFO_PRIMARY_P or
8302 BINFO_LOST_PRIMARY_P to be sure. */
8304 static tree
8306 {
8307 tree primary_base;
8314 }
8316 /* As above, but iterate until we reach the binfo that actually provides the
8317 vptr for BINFO. */
8319 static tree
8321 {
8325 {
8330 }
8332 }
8334 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8335 type. Note that the virtual inheritance might be above or below BINFO in
8336 the hierarchy. */
8338 bool
8340 {
8344 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8345 a morally virtual base. */
8348 }
8350 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8352 static int
8354 {
8358 }
8360 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8361 INDENT should be zero when called from the top level; it is
8362 incremented recursively. IGO indicates the next expected BINFO in
8363 inheritance graph ordering. */
8365 static tree
8367 dump_flags_t flags,
8368 tree binfo,
8369 tree igo,
8371 {
8373 tree base_binfo;
8381 {
8384 }
8399 {
8403 TFF_PLAIN_IDENTIFIER),
8405 }
8407 {
8410 }
8415 {
8419 {
8423 TFF_PLAIN_IDENTIFIER));
8424 }
8426 {
8430 TFF_PLAIN_IDENTIFIER));
8431 }
8433 {
8437 TFF_PLAIN_IDENTIFIER));
8438 }
8440 {
8444 TFF_PLAIN_IDENTIFIER));
8445 }
8449 }
8455 }
8457 /* Dump the BINFO hierarchy for T. */
8459 static void
8461 {
8473 }
8475 /* Debug interface to hierarchy dumping. */
8477 void
8479 {
8481 }
8483 static void
8485 {
8486 dump_flags_t flags;
8488 {
8491 }
8492 }
8494 static void
8496 {
8497 tree value;
8499 HOST_WIDE_INT elt;
8507 TFF_PLAIN_IDENTIFIER));
8514 }
8516 static void
8518 {
8519 dump_flags_t flags;
8526 {
8533 {
8538 }
8542 }
8545 }
8547 static void
8549 {
8550 dump_flags_t flags;
8557 {
8562 }
8565 }
8567 /* Dump a function or thunk and its thunkees. */
8569 static void
8571 {
8574 tree thunks;
8582 {
8592 else
8598 }
8602 }
8604 /* Dump the thunks for FN. */
8606 void
8608 {
8610 }
8612 /* Virtual function table initialization. */
8614 /* Create all the necessary vtables for T and its base classes. */
8616 static void
8618 {
8619 tree vbase;
8623 /* We lay out the primary and secondary vtables in one contiguous
8624 vtable. The primary vtable is first, followed by the non-virtual
8625 secondary vtables in inheritance graph order. */
8629 /* Then come the virtual bases, also in inheritance graph order. */
8631 {
8635 }
8639 }
8641 /* Initialize the vtable for BINFO with the INITS. */
8643 static void
8645 {
8646 tree decl;
8652 }
8654 /* Build the VTT (virtual table table) for T.
8655 A class requires a VTT if it has virtual bases.
8657 This holds
8658 1 - primary virtual pointer for complete object T
8659 2 - secondary VTTs for each direct non-virtual base of T which requires a
8660 VTT
8661 3 - secondary virtual pointers for each direct or indirect base of T which
8662 has virtual bases or is reachable via a virtual path from T.
8663 4 - secondary VTTs for each direct or indirect virtual base of T.
8665 Secondary VTTs look like complete object VTTs without part 4. */
8667 static void
8669 {
8670 tree type;
8671 tree vtt;
8672 tree index;
8675 /* Build up the initializers for the VTT. */
8680 /* If we didn't need a VTT, we're done. */
8684 /* Figure out the type of the VTT. */
8688 /* Now, build the VTT object itself. */
8691 /* Add the VTT to the vtables list. */
8696 }
8698 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8699 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8700 and CHAIN the vtable pointer for this binfo after construction is
8701 complete. VALUE can also be another BINFO, in which case we recurse. */
8703 static tree
8705 {
8706 tree vt;
8709 {
8715 else
8717 }
8720 }
8722 /* Data for secondary VTT initialization. */
8723 struct secondary_vptr_vtt_init_data
8724 {
8725 /* Is this the primary VTT? */
8728 /* Current index into the VTT. */
8729 tree index;
8731 /* Vector of initializers built up. */
8734 /* The type being constructed by this secondary VTT. */
8735 tree type_being_constructed;
8736 };
8738 /* Recursively build the VTT-initializer for BINFO (which is in the
8739 hierarchy dominated by T). INITS points to the end of the initializer
8740 list to date. INDEX is the VTT index where the next element will be
8741 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8742 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8743 for virtual bases of T. When it is not so, we build the constructor
8744 vtables for the BINFO-in-T variant. */
8746 static void
8749 {
8751 tree b;
8752 tree init;
8753 secondary_vptr_vtt_init_data data;
8756 /* We only need VTTs for subobjects with virtual bases. */
8760 /* We need to use a construction vtable if this is not the primary
8761 VTT. */
8763 {
8766 /* Record the offset in the VTT where this sub-VTT can be found. */
8768 }
8770 /* Add the address of the primary vtable for the complete object. */
8774 {
8777 }
8780 /* Recursively add the secondary VTTs for non-virtual bases. */
8785 /* Add secondary virtual pointers for all subobjects of BINFO with
8786 either virtual bases or reachable along a virtual path, except
8787 subobjects that are non-virtual primary bases. */
8797 /* data.inits might have grown as we added secondary virtual pointers.
8798 Make sure our caller knows about the new vector. */
8802 /* Add the secondary VTTs for virtual bases in inheritance graph
8803 order. */
8805 {
8810 }
8811 else
8812 /* Remove the ctor vtables we created. */
8814 }
8816 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8817 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8819 static tree
8821 {
8824 /* We don't care about bases that don't have vtables. */
8828 /* We're only interested in proper subobjects of the type being
8829 constructed. */
8833 /* We're only interested in bases with virtual bases or reachable
8834 via a virtual path from the type being constructed. */
8839 /* We're not interested in non-virtual primary bases. */
8843 /* Record the index where this secondary vptr can be found. */
8845 {
8850 {
8851 /* It's a primary virtual base, and this is not a
8852 construction vtable. Find the base this is primary of in
8853 the inheritance graph, and use that base's vtable
8854 now. */
8857 }
8858 }
8860 /* Add the initializer for the secondary vptr itself. */
8863 /* Advance the vtt index. */
8868 }
8870 /* Called from build_vtt_inits via dfs_walk. After building
8871 constructor vtables and generating the sub-vtt from them, we need
8872 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8873 binfo of the base whose sub vtt was generated. */
8875 static tree
8877 {
8881 /* If this class has no vtable, none of its bases do. */
8885 /* This might be a primary base, so have no vtable in this
8886 hierarchy. */
8889 /* If we scribbled the construction vtable vptr into BINFO, clear it
8890 out now. */
8896 }
8898 /* Build the construction vtable group for BINFO which is in the
8899 hierarchy dominated by T. */
8901 static void
8903 {
8904 tree type;
8905 tree vtbl;
8906 tree id;
8907 tree vbase;
8910 /* See if we've already created this construction vtable group. */
8916 /* Build a version of VTBL (with the wrong type) for use in
8917 constructing the addresses of secondary vtables in the
8918 construction vtable group. */
8921 /* Don't export construction vtables from shared libraries. Even on
8922 targets that don't support hidden visibility, this tells
8923 can_refer_decl_in_current_unit_p not to assume that it's safe to
8924 access from a different compilation unit (bz 54314). */
8932 /* Add the vtables for each of our virtual bases using the vbase in T
8933 binfo. */
8935 vbase;
8937 {
8938 tree b;
8945 }
8947 /* Figure out the type of the construction vtable. */
8954 /* Initialize the construction vtable. */
8958 }
8960 /* Add the vtbl initializers for BINFO (and its bases other than
8961 non-virtual primaries) to the list of INITS. BINFO is in the
8962 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
8963 the constructor the vtbl inits should be accumulated for. (If this
8964 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
8965 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
8966 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
8967 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
8968 but are not necessarily the same in terms of layout. */
8970 static void
8972 tree orig_binfo,
8973 tree rtti_binfo,
8974 tree vtbl,
8975 tree t,
8977 {
8979 tree base_binfo;
8984 /* If it doesn't have a vptr, we don't do anything. */
8988 /* If we're building a construction vtable, we're not interested in
8989 subobjects that don't require construction vtables. */
8995 /* Build the initializers for the BINFO-in-T vtable. */
8998 /* Walk the BINFO and its bases. We walk in preorder so that as we
8999 initialize each vtable we can figure out at what offset the
9000 secondary vtable lies from the primary vtable. We can't use
9001 dfs_walk here because we need to iterate through bases of BINFO
9002 and RTTI_BINFO simultaneously. */
9004 {
9005 /* Skip virtual bases. */
9011 inits);
9012 }
9013 }
9015 /* Called from accumulate_vtbl_inits. Adds the initializers for the
9016 BINFO vtable to L. */
9018 static void
9020 tree orig_binfo,
9021 tree rtti_binfo,
9022 tree orig_vtbl,
9023 tree t,
9025 {
9032 {
9033 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9034 primary virtual base. If it is not the same primary in
9035 the hierarchy of T, we'll need to generate a ctor vtable
9036 for it, to place at its location in T. If it is the same
9037 primary, we still need a VTT entry for the vtable, but it
9038 should point to the ctor vtable for the base it is a
9039 primary for within the sub-hierarchy of RTTI_BINFO.
9041 There are three possible cases:
9043 1) We are in the same place.
9044 2) We are a primary base within a lost primary virtual base of
9045 RTTI_BINFO.
9046 3) We are primary to something not a base of RTTI_BINFO. */
9048 tree b;
9051 /* First, look through the bases we are primary to for RTTI_BINFO
9052 or a virtual base. */
9055 {
9060 }
9061 /* If we run out of primary links, keep looking down our
9062 inheritance chain; we might be an indirect primary. */
9066 found:
9068 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9069 base B and it is a base of RTTI_BINFO, this is case 2. In
9070 either case, we share our vtable with LAST, i.e. the
9071 derived-most base within B of which we are a primary. */
9074 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9075 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9076 binfo_ctor_vtable after everything's been set up. */
9079 /* Otherwise, this is case 3 and we get our own. */
9080 }
9087 {
9088 tree index;
9091 /* Add the initializer for this vtable. */
9095 /* Figure out the position to which the VPTR should point. */
9101 }
9104 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9105 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9106 straighten this out. */
9109 /* Throw away any unneeded intializers. */
9111 else
9112 /* For an ordinary vtable, set BINFO_VTABLE. */
9114 }
9119 /* Construct the initializer for BINFO's virtual function table. BINFO
9120 is part of the hierarchy dominated by T. If we're building a
9121 construction vtable, the ORIG_BINFO is the binfo we should use to
9122 find the actual function pointers to put in the vtable - but they
9123 can be overridden on the path to most-derived in the graph that
9124 ORIG_BINFO belongs. Otherwise,
9125 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9126 BINFO that should be indicated by the RTTI information in the
9127 vtable; it will be a base class of T, rather than T itself, if we
9128 are building a construction vtable.
9130 The value returned is a TREE_LIST suitable for wrapping in a
9131 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9132 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9133 number of non-function entries in the vtable.
9135 It might seem that this function should never be called with a
9136 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9137 base is always subsumed by a derived class vtable. However, when
9138 we are building construction vtables, we do build vtables for
9139 primary bases; we need these while the primary base is being
9140 constructed. */
9142 static void
9144 tree orig_binfo,
9145 tree t,
9146 tree rtti_binfo,
9149 {
9150 tree v;
9151 vtbl_init_data vid;
9153 tree vbinfo;
9157 /* Initialize VID. */
9165 /* The first vbase or vcall offset is at index -3 in the vtable. */
9168 /* Add entries to the vtable for RTTI. */
9171 /* Create an array for keeping track of the functions we've
9172 processed. When we see multiple functions with the same
9173 signature, we share the vcall offsets. */
9175 /* Add the vcall and vbase offset entries. */
9178 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9179 build_vbase_offset_vtbl_entries. */
9184 /* If the target requires padding between data entries, add that now. */
9186 {
9191 /* Move data entries into their new positions and add padding
9192 after the new positions. Iterate backwards so we don't
9193 overwrite entries that we would need to process later. */
9196 ix--)
9197 {
9205 {
9209 null_pointer_node);
9210 }
9211 }
9212 }
9217 /* The initializers for virtual functions were built up in reverse
9218 order. Straighten them out and add them to the running list in one
9219 step. */
9228 /* Go through all the ordinary virtual functions, building up
9229 initializers. */
9231 {
9232 tree delta;
9233 tree vcall_index;
9240 {
9244 {
9247 }
9249 }
9251 /* If the only definition of this function signature along our
9252 primary base chain is from a lost primary, this vtable slot will
9253 never be used, so just zero it out. This is important to avoid
9254 requiring extra thunks which cannot be generated with the function.
9256 We first check this in update_vtable_entry_for_fn, so we handle
9257 restored primary bases properly; we also need to do it here so we
9258 zero out unused slots in ctor vtables, rather than filling them
9259 with erroneous values (though harmless, apart from relocation
9260 costs). */
9265 {
9266 /* Pull the offset for `this', and the function to call, out of
9267 the list. */
9274 /* You can't call an abstract virtual function; it's abstract.
9275 So, we replace these functions with __pure_virtual. */
9277 {
9280 {
9282 abort_fndecl_addr
9286 }
9287 }
9288 /* Likewise for deleted virtuals. */
9290 {
9292 {
9296 dvirt_fn = push_library_fn
9300 }
9305 }
9306 else
9307 {
9309 {
9314 }
9315 /* Take the address of the function, considering it to be of an
9316 appropriate generic type. */
9320 /* Don't refer to a virtual destructor from a constructor
9321 vtable or a vtable for an abstract class, since destroying
9322 an object under construction is undefined behavior and we
9323 don't want it to be considered a candidate for speculative
9324 devirtualization. But do create the thunk for ABI
9325 compliance. */
9330 }
9331 }
9333 /* And add it to the chain of initializers. */
9335 {
9340 else
9342 {
9348 }
9349 }
9350 else
9352 }
9353 }
9355 /* Adds to vid->inits the initializers for the vbase and vcall
9356 offsets in BINFO, which is in the hierarchy dominated by T. */
9358 static void
9360 {
9361 tree b;
9363 /* If this is a derived class, we must first create entries
9364 corresponding to the primary base class. */
9369 /* Add the vbase entries for this base. */
9371 /* Add the vcall entries for this base. */
9373 }
9375 /* Returns the initializers for the vbase offset entries in the vtable
9376 for BINFO (which is part of the class hierarchy dominated by T), in
9377 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9378 where the next vbase offset will go. */
9380 static void
9382 {
9383 tree vbase;
9384 tree t;
9385 tree non_primary_binfo;
9387 /* If there are no virtual baseclasses, then there is nothing to
9388 do. */
9394 /* We might be a primary base class. Go up the inheritance hierarchy
9395 until we find the most derived class of which we are a primary base:
9396 it is the offset of that which we need to use. */
9399 {
9400 tree b;
9402 /* If we have reached a virtual base, then it must be a primary
9403 base (possibly multi-level) of vid->binfo, or we wouldn't
9404 have called build_vcall_and_vbase_vtbl_entries for it. But it
9405 might be a lost primary, so just skip down to vid->binfo. */
9407 {
9410 }
9416 }
9418 /* Go through the virtual bases, adding the offsets. */
9420 vbase;
9422 {
9423 tree b;
9424 tree delta;
9429 /* Find the instance of this virtual base in the complete
9430 object. */
9433 /* If we've already got an offset for this virtual base, we
9434 don't need another one. */
9439 /* Figure out where we can find this vbase offset. */
9448 /* The vbase offset had better be the same. */
9451 /* The next vbase will come at a more negative offset. */
9455 /* The initializer is the delta from BINFO to this virtual base.
9456 The vbase offsets go in reverse inheritance-graph order, and
9457 we are walking in inheritance graph order so these end up in
9458 the right order. */
9465 }
9466 }
9468 /* Adds the initializers for the vcall offset entries in the vtable
9469 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9470 to VID->INITS. */
9472 static void
9474 {
9475 /* We only need these entries if this base is a virtual base. We
9476 compute the indices -- but do not add to the vtable -- when
9477 building the main vtable for a class. */
9480 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9481 correspond to VID->DERIVED), we are building a primary
9482 construction virtual table. Since this is a primary
9483 virtual table, we do not need the vcall offsets for
9484 BINFO. */
9486 {
9487 /* We need a vcall offset for each of the virtual functions in this
9488 vtable. For example:
9490 class A { virtual void f (); };
9491 class B1 : virtual public A { virtual void f (); };
9492 class B2 : virtual public A { virtual void f (); };
9493 class C: public B1, public B2 { virtual void f (); };
9495 A C object has a primary base of B1, which has a primary base of A. A
9496 C also has a secondary base of B2, which no longer has a primary base
9497 of A. So the B2-in-C construction vtable needs a secondary vtable for
9498 A, which will adjust the A* to a B2* to call f. We have no way of
9499 knowing what (or even whether) this offset will be when we define B2,
9500 so we store this "vcall offset" in the A sub-vtable and look it up in
9501 a "virtual thunk" for B2::f.
9503 We need entries for all the functions in our primary vtable and
9504 in our non-virtual bases' secondary vtables. */
9506 /* If we are just computing the vcall indices -- but do not need
9507 the actual entries -- not that. */
9510 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9512 }
9513 }
9515 /* Build vcall offsets, starting with those for BINFO. */
9517 static void
9519 {
9521 tree primary_binfo;
9522 tree base_binfo;
9524 /* Don't walk into virtual bases -- except, of course, for the
9525 virtual base for which we are building vcall offsets. Any
9526 primary virtual base will have already had its offsets generated
9527 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9531 /* If BINFO has a primary base, process it first. */
9536 /* Add BINFO itself to the list. */
9539 /* Scan the non-primary bases of BINFO. */
9543 }
9545 /* Called from build_vcall_offset_vtbl_entries_r. */
9547 static void
9549 {
9550 /* Make entries for the rest of the virtuals. */
9551 tree orig_fn;
9553 /* The ABI requires that the methods be processed in declaration
9554 order. */
9556 orig_fn;
9560 }
9562 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9564 static void
9566 {
9568 tree vcall_offset;
9569 tree derived_entry;
9571 /* If there is already an entry for a function with the same
9572 signature as FN, then we do not need a second vcall offset.
9573 Check the list of functions already present in the derived
9574 class vtable. */
9576 {
9578 /* We only use one vcall offset for virtual destructors,
9579 even though there are two virtual table entries. */
9583 }
9585 /* If we are building these vcall offsets as part of building
9586 the vtable for the most derived class, remember the vcall
9587 offset. */
9589 {
9592 }
9594 /* The next vcall offset will be found at a more negative
9595 offset. */
9599 /* Keep track of this function. */
9603 {
9604 tree base;
9605 tree fn;
9607 /* Find the overriding function. */
9611 else
9612 {
9615 /* The vbase we're working on is a primary base of
9616 vid->binfo. But it might be a lost primary, so its
9617 BINFO_OFFSET might be wrong, so we just use the
9618 BINFO_OFFSET from vid->binfo. */
9624 vcall_offset);
9625 }
9626 /* Add the initializer to the vtable. */
9628 }
9629 }
9631 /* Return vtbl initializers for the RTTI entries corresponding to the
9632 BINFO's vtable. The RTTI entries should indicate the object given
9633 by VID->rtti_binfo. */
9635 static void
9637 {
9638 tree b;
9639 tree t;
9640 tree offset;
9641 tree decl;
9642 tree init;
9646 /* To find the complete object, we will first convert to our most
9647 primary base, and then add the offset in the vtbl to that value. */
9652 /* The second entry is the address of the typeinfo object. */
9655 else
9658 /* Convert the declaration to a type that can be stored in the
9659 vtable. */
9663 /* Add the offset-to-top entry. It comes earlier in the vtable than
9664 the typeinfo entry. Convert the offset to look like a
9665 function pointer, so that we can put it in the vtable. */
9668 }
9670 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9671 accessibility. */
9673 bool
9675 {
9678 }
9680 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9682 bool
9684 {
9688 }
9690 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9691 class between them, if any. */
9693 tree
9695 {
9707 {
9710 }
9714 }