| blob | 98e62c6ad45009b0710e57060cd8a1c998bc9dd4 |
1 /* Functions related to building classes and their related objects.
2 Copyright (C) 1987-2017 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 /* Variables shared between class.c and call.c. */
228 /* Return a COND_EXPR that executes TRUE_STMT if this execution of the
229 'structor is in charge of 'structing virtual bases, or FALSE_STMT
230 otherwise. */
232 tree
234 {
244 }
246 /* Convert to or from a base subobject. EXPR is an expression of type
247 `A' or `A*', an expression of type `B' or `B*' is returned. To
248 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
249 the B base instance within A. To convert base A to derived B, CODE
250 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
251 In this latter case, A must not be a morally virtual base of B.
252 NONNULL is true if EXPR is known to be non-NULL (this is only
253 needed when EXPR is of pointer type). CV qualifiers are preserved
254 from EXPR. */
256 tree
258 tree expr,
259 tree binfo,
261 tsubst_flags_t complain)
262 {
265 tree probe;
266 tree offset;
267 tree target_type;
269 tree ptr_target_type;
280 {
286 }
294 {
295 /* This can happen when adjust_result_of_qualified_name_lookup can't
296 find a unique base binfo in a call to a member function. We
297 couldn't give the diagnostic then since we might have been calling
298 a static member function, so we do it now. In other cases, eg.
299 during error recovery (c++/71979), we may not have a base at all. */
301 {
305 }
307 }
314 /* Nothing to do. */
318 {
320 {
322 {
325 "pointer to derived class %qT because the base is "
327 else
331 }
332 else
333 {
339 else
343 }
344 }
346 }
349 {
351 /* This must happen before the call to save_expr. */
353 }
354 else
360 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
361 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
362 expression returned matches the input. */
363 target_type = cp_build_qualified_type
367 /* Do we need to look in the vtable for the real offset? */
370 /* Don't bother with the calculations inside sizeof; they'll ICE if the
371 source type is incomplete and the pointer value doesn't matter. In a
372 template (even in instantiate_non_dependent_expr), we don't have vtables
373 set up properly yet, and the value doesn't matter there either; we're
374 just interested in the result of overload resolution. */
376 || processing_template_decl
378 {
381 }
383 /* If we're in an NSDMI, we don't have the full constructor context yet
384 that we need for converting to a virtual base, so just build a stub
385 CONVERT_EXPR and expand it later in bot_replace. */
388 {
392 }
394 /* Do we need to check for a null pointer? */
396 {
397 /* If we know the conversion will not actually change the value
398 of EXPR, then we can avoid testing the expression for NULL.
399 We have to avoid generating a COMPONENT_REF for a base class
400 field, because other parts of the compiler know that such
401 expressions are always non-NULL. */
405 }
407 /* Protect against multiple evaluation if necessary. */
411 /* Now that we've saved expr, build the real null test. */
413 {
417 /* This is a compiler generated comparison, don't emit
418 e.g. -Wnonnull-compare warning for it. */
420 }
422 /* If this is a simple base reference, express it as a COMPONENT_REF. */
424 /* We don't build base fields for empty bases, and they aren't very
425 interesting to the optimizers anyway. */
427 {
436 }
439 {
440 /* Going via virtual base V_BINFO. We need the static offset
441 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
442 V_BINFO. That offset is an entry in D_BINFO's vtable. */
443 tree v_offset;
446 {
447 /* In a base member initializer, we cannot rely on the
448 vtable being set up. We have to indirect via the
449 vtt_parm. */
450 tree t;
456 }
457 else
458 {
462 {
467 }
469 complain),
471 }
479 v_offset);
491 /* Negative fixed_type_p means this is a constructor or destructor;
492 virtual base layout is fixed in in-charge [cd]tors, but not in
493 base [cd]tors. */
494 offset = build_if_in_charge
496 v_offset);
497 else
499 }
507 {
512 }
513 else
516 indout:
518 {
522 }
524 out:
530 }
532 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
533 Perform a derived-to-base conversion by recursively building up a
534 sequence of COMPONENT_REFs to the appropriate base fields. */
536 static tree
538 {
541 tree field;
544 {
545 tree temp;
549 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
550 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
551 an lvalue in the front end; only _DECLs and _REFs are lvalues
552 in the back end. */
558 }
560 /* Recurse. */
565 /* Is this the base field created by build_base_field? */
569 /* If we're looking for a field in the most-derived class,
570 also check the field offset; we can have two base fields
571 of the same type if one is an indirect virtual base and one
572 is a direct non-virtual base. */
576 {
577 /* We don't use build_class_member_access_expr here, as that
578 has unnecessary checks, and more importantly results in
579 recursive calls to dfs_walk_once. */
585 /* Mark the expression const or volatile, as appropriate.
586 Even though we've dealt with the type above, we still have
587 to mark the expression itself. */
594 }
596 /* Didn't find the base field?!? */
598 }
600 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
601 type is a class type or a pointer to a class type. In the former
602 case, TYPE is also a class type; in the latter it is another
603 pointer type. If CHECK_ACCESS is true, an error message is emitted
604 if TYPE is inaccessible. If OBJECT has pointer type, the value is
605 assumed to be non-NULL. */
607 tree
609 tsubst_flags_t complain)
610 {
611 tree binfo;
612 tree object_type;
615 {
618 }
619 else
628 }
630 /* EXPR is an expression with unqualified class type. BASE is a base
631 binfo of that class type. Returns EXPR, converted to the BASE
632 type. This function assumes that EXPR is the most derived class;
633 therefore virtual bases can be found at their static offsets. */
635 tree
637 {
638 tree expr_type;
642 {
643 /* If this is a non-empty base, use a COMPONENT_REF. */
647 /* We use fold_build2 and fold_convert below to simplify the trees
648 provided to the optimizers. It is not safe to call these functions
649 when processing a template because they do not handle C++-specific
650 trees. */
658 }
661 }
663 \f
664 tree
666 {
670 /* Can happen in case of duplicate base types (c++/59082). */
674 /* First, convert to the requested type. */
679 /* Second, the requested type may not be the owner of its own vptr.
680 If not, convert to the base class that owns it. We cannot use
681 convert_to_base here, because VCONTEXT may appear more than once
682 in the inheritance hierarchy of TYPE, and thus direct conversion
683 between the types may be ambiguous. Following the path back up
684 one step at a time via primary bases avoids the problem. */
688 {
691 }
694 }
696 /* Given an object INSTANCE, return an expression which yields the
697 vtable element corresponding to INDEX. There are many special
698 cases for INSTANCE which we take care of here, mainly to avoid
699 creating extra tree nodes when we don't have to. */
701 static tree
703 {
704 tree aref;
707 /* Try to figure out what a reference refers to, and
708 access its virtual function table directly. */
716 {
721 }
730 }
732 tree
734 {
738 }
740 /* Given a stable object pointer INSTANCE_PTR, return an expression which
741 yields a function pointer corresponding to vtable element INDEX. */
743 tree
745 {
746 tree aref;
749 tf_warning_or_error),
750 idx);
752 /* When using function descriptors, the address of the
753 vtable entry is treated as a function pointer. */
758 /* Remember this as a method reference, for later devirtualization. */
762 }
764 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
765 for the given TYPE. */
767 static tree
769 {
771 }
773 /* DECL is an entity associated with TYPE, like a virtual table or an
774 implicitly generated constructor. Determine whether or not DECL
775 should have external or internal linkage at the object file
776 level. This routine does not deal with COMDAT linkage and other
777 similar complexities; it simply sets TREE_PUBLIC if it possible for
778 entities in other translation units to contain copies of DECL, in
779 the abstract. */
781 void
783 {
786 }
788 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
789 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
790 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
792 static tree
794 {
795 tree decl;
798 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
799 now to avoid confusion in mangle_decl. */
810 /* The vtable has not been defined -- yet. */
814 /* Mark the VAR_DECL node representing the vtable itself as a
815 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
816 is rather important that such things be ignored because any
817 effort to actually generate DWARF for them will run into
818 trouble when/if we encounter code like:
820 #pragma interface
821 struct S { virtual void member (); };
823 because the artificial declaration of the vtable itself (as
824 manufactured by the g++ front end) will say that the vtable is
825 a static member of `S' but only *after* the debug output for
826 the definition of `S' has already been output. This causes
827 grief because the DWARF entry for the definition of the vtable
828 will try to refer back to an earlier *declaration* of the
829 vtable as a static member of `S' and there won't be one. We
830 might be able to arrange to have the "vtable static member"
831 attached to the member list for `S' before the debug info for
832 `S' get written (which would solve the problem) but that would
833 require more intrusive changes to the g++ front end. */
837 }
839 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
840 or even complete. If this does not exist, create it. If COMPLETE is
841 nonzero, then complete the definition of it -- that will render it
842 impossible to actually build the vtable, but is useful to get at those
843 which are known to exist in the runtime. */
845 tree
847 {
848 tree decl;
857 {
860 }
863 }
865 /* Build the primary virtual function table for TYPE. If BINFO is
866 non-NULL, build the vtable starting with the initial approximation
867 that it is the same as the one which is the head of the association
868 list. Returns a nonzero value if a new vtable is actually
869 created. */
871 static int
873 {
874 tree decl;
875 tree virtuals;
880 {
882 /* We have already created a vtable for this base, so there's
883 no need to do it again. */
890 }
891 else
892 {
895 }
898 {
901 }
903 /* Initialize the association list for this type, based
904 on our first approximation. */
909 }
911 /* Give BINFO a new virtual function table which is initialized
912 with a skeleton-copy of its original initialization. The only
913 entry that changes is the `delta' entry, so we can really
914 share a lot of structure.
916 FOR_TYPE is the most derived type which caused this table to
917 be needed.
919 Returns nonzero if we haven't met BINFO before.
921 The order in which vtables are built (by calling this function) for
922 an object must remain the same, otherwise a binary incompatibility
923 can result. */
925 static int
927 {
929 /* We already created a vtable for this base. There's no need to
930 do it again. */
933 /* Remember that we've created a vtable for this BINFO, so that we
934 don't try to do so again. */
937 /* Make fresh virtual list, so we can smash it later. */
940 /* Secondary vtables are laid out as part of the same structure as
941 the primary vtable. */
944 }
946 /* Create a new vtable for BINFO which is the hierarchy dominated by
947 T. Return nonzero if we actually created a new vtable. */
949 static int
951 {
953 /* In this case, it is *type*'s vtable we are modifying. We start
954 with the approximation that its vtable is that of the
955 immediate base class. */
957 else
958 /* This is our very own copy of `basetype' to play with. Later,
959 we will fill in all the virtual functions that override the
960 virtual functions in these base classes which are not defined
961 by the current type. */
963 }
965 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
966 (which is in the hierarchy dominated by T) list FNDECL as its
967 BV_FN. DELTA is the required constant adjustment from the `this'
968 pointer where the vtable entry appears to the `this' required when
969 the function is actually called. */
971 static void
973 tree binfo,
974 tree fndecl,
975 tree delta,
977 {
978 tree v;
984 {
985 /* We need a new vtable for BINFO. */
987 {
988 /* If we really did make a new vtable, we also made a copy
989 of the BINFO_VIRTUALS list. Now, we have to find the
990 corresponding entry in that list. */
995 }
1000 }
1001 }
1003 \f
1004 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
1005 METHOD is being injected via a using_decl. Returns true if the
1006 method could be added to the method vec. */
1008 bool
1010 {
1014 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1022 /* Check to see if we've already got this method. */
1024 {
1026 tree fn_type;
1027 tree method_type;
1028 tree parms1;
1029 tree parms2;
1034 /* Two using-declarations can coexist, we'll complain about ambiguity in
1035 overload resolution. */
1037 /* Except handle inherited constructors specially. */
1041 /* [over.load] Member function declarations with the
1042 same name and the same parameter types cannot be
1043 overloaded if any of them is a static member
1044 function declaration.
1046 [over.load] Member function declarations with the same name and
1047 the same parameter-type-list as well as member function template
1048 declarations with the same name, the same parameter-type-list, and
1049 the same template parameter lists cannot be overloaded if any of
1050 them, but not all, have a ref-qualifier.
1052 [namespace.udecl] When a using-declaration brings names
1053 from a base class into a derived class scope, member
1054 functions in the derived class override and/or hide member
1055 functions with the same name and parameter types in a base
1056 class (rather than conflicting). */
1062 /* Compare the quals on the 'this' parm. Don't compare
1063 the whole types, as used functions are treated as
1064 coming from the using class in overload resolution. */
1067 /* Either both or neither need to be ref-qualified for
1068 differing quals to allow overloading. */
1075 /* For templates, the return type and template parameters
1076 must be identical. */
1089 /* Bring back parameters omitted from an inherited ctor. */
1100 {
1101 /* If these are versions of the same function, process and
1102 move on. */
1108 {
1110 {
1114 {
1116 {
1117 /* Inheriting the same constructor along different
1118 paths, combine them. */
1119 SET_DECL_INHERITED_CTOR
1122 /* And discard the new one. */
1124 }
1125 else
1126 /* Inherited ctors can coexist until overload
1127 resolution. */
1129 }
1135 basef);
1136 }
1137 /* Otherwise defer to the other function. */
1139 }
1142 /* Defer to the local function. */
1146 {
1147 /* Remove the inherited constructor. */
1150 }
1151 else
1152 {
1158 }
1159 }
1160 }
1162 /* A class should never have more than one destructor. */
1173 }
1175 /* Subroutines of finish_struct. */
1177 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1178 legit, otherwise return 0. */
1180 static int
1182 {
1183 tree elem;
1191 {
1193 {
1197 else
1200 }
1201 else
1202 {
1203 /* They're changing the access to the same thing they changed
1204 it to before. That's OK. */
1205 ;
1206 }
1207 }
1208 else
1209 {
1211 tf_warning_or_error);
1214 }
1216 }
1218 /* Return the access node for DECL's access in its enclosing class. */
1220 tree
1222 {
1226 }
1228 /* Process the USING_DECL, which is a member of T. */
1230 static void
1232 {
1237 tree old_value;
1242 tf_warning_or_error);
1244 {
1249 else
1251 }
1259 ;
1261 {
1263 /* It's OK to use functions from a base when there are functions with
1265 else
1266 {
1273 }
1274 }
1276 {
1283 }
1285 /* Make type T see field decl FDECL with access ACCESS. */
1288 {
1291 }
1292 else
1294 }
1295 \f
1296 /* Data structure for find_abi_tags_r, below. */
1298 struct abi_tag_data
1299 {
1303 };
1305 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1306 in the context of P. TAG can be either an identifier (the DECL_NAME of
1307 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1309 static void
1311 {
1313 {
1315 {
1316 /* We're collecting tags from template arguments or from
1317 the type of a variable or function return type. */
1320 /* Don't inherit this tag multiple times. */
1324 {
1325 /* Tags inherited from type template arguments are only used
1326 to avoid warnings. */
1329 }
1330 /* For functions and variables we want to warn, too. */
1331 }
1333 /* Otherwise we're diagnosing missing tags. */
1335 {
1340 }
1342 {
1346 }
1348 {
1353 }
1354 else
1355 {
1359 {
1363 }
1364 }
1365 }
1366 }
1368 /* Find all the ABI tags in the attribute list ATTR and either call
1369 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1371 static void
1373 {
1380 {
1385 else
1387 }
1388 }
1390 /* Find all the ABI tags on T and its enclosing scopes and either call
1391 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1393 static void
1395 {
1397 {
1398 tree attr;
1400 {
1403 }
1404 else
1405 {
1408 }
1410 }
1411 }
1413 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1414 types with ABI tags, add the corresponding identifiers to the VEC in
1415 *DATA and set IDENTIFIER_MARKED. */
1417 static tree
1419 {
1423 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1424 anyway, but let's make sure of it. */
1432 }
1434 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1435 IDENTIFIER_MARKED on its ABI tags. */
1437 static tree
1439 {
1443 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1444 anyway, but let's make sure of it. */
1452 }
1454 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1455 scopes. */
1457 static void
1459 {
1462 {
1465 {
1466 /* Template arguments are part of the signature. */
1469 {
1472 }
1473 }
1475 /* A function's parameter types are part of the signature, so
1476 we don't need to inherit any tags that are also in them. */
1481 }
1482 }
1484 /* Check that T has all the ABI tags that subobject SUBOB has, or
1485 warn if not. If T is a (variable or function) declaration, also
1486 return any missing tags, and add them to T if JUST_CHECKING is false. */
1488 static tree
1490 {
1498 /* No need to worry about things local to this TU. */
1514 {
1517 }
1518 else
1519 {
1523 else
1527 }
1532 }
1534 /* Check that DECL has all the ABI tags that are used in parts of its type
1535 that are not reflected in its mangled name. */
1537 void
1539 {
1546 }
1548 /* Return any ABI tags that are used in parts of the type of DECL
1549 that are not reflected in its mangled name. This function is only
1550 used in backward-compatible mangling for ABI <11. */
1552 tree
1554 {
1558 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1559 that we can use this function for setting need_abi_warning
1560 regardless of the current flag_abi_version. */
1563 else
1565 }
1567 void
1569 {
1579 {
1582 {
1586 }
1587 }
1589 // If we found some tags on our template arguments, add them to our
1590 // abi_tag attribute.
1592 {
1596 else
1600 }
1603 }
1605 /* Return true, iff class T has a non-virtual destructor that is
1606 accessible from outside the class heirarchy (i.e. is public, or
1607 there's a suitable friend. */
1609 static bool
1611 {
1614 /* An implicitly declared destructor is always public. And,
1615 if it were virtual, we would have created it by now. */
1630 }
1632 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1633 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1634 properties of the bases. */
1636 static void
1640 {
1644 tree base_binfo;
1645 tree binfo;
1655 {
1664 /* If any base class is non-literal, so is the derived class. */
1668 /* If the base class doesn't have copy constructors or
1669 assignment operators that take const references, then the
1670 derived class cannot have such a member automatically
1671 generated. */
1680 /* A virtual base does not effect nearly emptiness. */
1681 ;
1683 {
1685 /* And if there is more than one nearly empty base, then the
1686 derived class is not nearly empty either. */
1688 else
1689 /* Remember we've seen one. */
1691 }
1693 /* If the base class is not empty or nearly empty, then this
1694 class cannot be nearly empty. */
1697 /* A lot of properties from the bases also apply to the derived
1698 class. */
1715 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1718 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1724 /* A standard-layout class is a class that:
1725 ...
1726 * has no non-standard-layout base classes, */
1729 {
1730 tree basefield;
1731 /* ...has no base classes of the same type as the first non-static
1732 data member... */
1734 && (same_type_ignoring_top_level_qualifiers_p
1737 else
1738 /* ...either has no non-static data members in the most-derived
1739 class and at most one base class with non-static data
1740 members, or has no base classes with non-static data
1741 members */
1747 {
1750 else
1753 }
1754 }
1756 /* Don't bother collecting tm attributes if transactional memory
1757 support is not enabled. */
1759 {
1763 }
1766 }
1768 /* If one of the base classes had TM attributes, and the current class
1769 doesn't define its own, then the current class inherits one. */
1771 {
1774 }
1775 }
1777 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1778 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1779 that have had a nearly-empty virtual primary base stolen by some
1780 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1781 T. */
1783 static void
1785 {
1789 tree base_binfo;
1791 /* Determine the primary bases of our bases. */
1794 {
1797 /* See if we're the non-virtual primary of our inheritance
1798 chain. */
1800 {
1807 /* We are the primary binfo. */
1809 }
1810 /* Determine if we have a virtual primary base, and mark it so.
1811 */
1813 {
1817 /* Someone already claimed this base. */
1819 else
1820 {
1821 tree delta;
1826 /* A virtual binfo might have been copied from within
1827 another hierarchy. As we're about to use it as a
1828 primary base, make sure the offsets match. */
1836 }
1837 }
1838 }
1840 /* First look for a dynamic direct non-virtual base. */
1842 {
1846 {
1849 }
1850 }
1852 /* A "nearly-empty" virtual base class can be the primary base
1853 class, if no non-virtual polymorphic base can be found. Look for
1854 a nearly-empty virtual dynamic base that is not already a primary
1855 base of something in the hierarchy. If there is no such base,
1856 just pick the first nearly-empty virtual base. */
1862 {
1864 {
1865 /* Found one that is not primary. */
1868 }
1870 /* Remember the first candidate. */
1872 }
1874 found:
1875 /* If we've got a primary base, use it. */
1877 {
1882 /* We are stealing a primary base. */
1886 {
1887 tree delta;
1890 /* A virtual binfo might have been copied from within
1891 another hierarchy. As we're about to use it as a primary
1892 base, make sure the offsets match. */
1897 }
1904 }
1905 }
1907 /* Update the variant types of T. */
1909 void
1911 {
1912 tree variants;
1918 variants;
1920 {
1921 /* These fields are in the _TYPE part of the node, not in
1922 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1932 /* Copy whatever these are holding today. */
1935 }
1936 }
1938 /* KLASS is a class that we're applying may_alias to after the body is
1939 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
1940 canonical type(s) will be implicitly updated. */
1942 static void
1944 {
1953 }
1955 /* Early variant fixups: we apply attributes at the beginning of the class
1956 definition, and we need to fix up any variants that have already been
1957 made via elaborated-type-specifier so that check_qualified_type works. */
1959 void
1961 {
1962 tree variants;
1976 variants;
1978 {
1979 /* These are the two fields that check_qualified_type looks at and
1980 are affected by attributes. */
1985 else
1990 }
1991 }
1992 \f
1993 /* Set memoizing fields and bits of T (and its variants) for later
1994 use. */
1996 static void
1998 {
1999 /* Fix up variants (if any). */
2003 /* For a class w/o baseclasses, 'finish_struct' has set
2004 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2005 Similarly for a class whose base classes do not have vtables.
2006 When neither of these is true, we might have removed abstract
2007 virtuals (by providing a definition), added some (by declaring
2008 new ones), or redeclared ones from a base class. We need to
2009 recalculate what's really an abstract virtual at this point (by
2010 looking in the vtables). */
2013 /* If this type has a copy constructor or a destructor, force its
2014 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2015 nonzero. This will cause it to be passed by invisible reference
2016 and prevent it from being returned in a register. */
2019 {
2020 tree variants;
2023 {
2026 }
2027 }
2028 }
2030 /* Issue warnings about T having private constructors, but no friends,
2031 and so forth.
2033 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2034 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2035 non-private static member functions. */
2037 static void
2039 {
2044 /* If the class has friends, those entities might create and
2045 access instances, so we should not warn. */
2048 /* We will have warned when the template was declared; there's
2049 no need to warn on every instantiation. */
2051 /* There's no reason to even consider warning about this
2052 class. */
2055 /* We only issue one warning, if more than one applies, because
2056 otherwise, on code like:
2058 class A {
2059 // Oops - forgot `public:'
2060 A();
2061 A(const A&);
2062 ~A();
2063 };
2065 we warn several times about essentially the same problem. */
2067 /* Check to see if all (non-constructor, non-destructor) member
2068 functions are private. (Since there are no friends or
2069 non-private statics, we can't ever call any of the private member
2070 functions.) */
2075 /* We're not interested in compiler-generated methods; they don't
2078 {
2080 /* A non-private static member function is just like a
2081 friend; it can create and invoke private member
2082 functions, and be accessed without a class
2083 instance. */
2087 /* Keep searching for a static member function. */
2088 }
2093 {
2094 /* There are no non-private methods, and there's at least one
2095 private member function that isn't a constructor or
2096 destructor. (If all the private members are
2097 constructors/destructors we want to use the code below that
2098 issues error messages specifically referring to
2099 constructors/destructors.) */
2105 {
2108 }
2110 {
2114 }
2115 }
2117 /* Even if some of the member functions are non-private, the class
2118 won't be useful for much if all the constructors or destructors
2119 are private: such an object can never be created or destroyed. */
2122 {
2125 t);
2127 }
2129 /* Warn about classes that have private constructors and no friends. */
2131 /* Implicitly generated constructors are always public. */
2133 {
2137 /* If a non-template class does not define a copy
2138 constructor, one is defined for it, enabling it to avoid
2139 this warning. For a template class, this does not
2140 happen, and so we would normally get a warning on:
2142 template <class T> class C { private: C(); };
2144 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2145 complete non-template or fully instantiated classes have this
2146 flag set. */
2149 else
2155 /* Ideally, we wouldn't count any constructor that takes
2156 an argument of the class type as a parameter, because
2157 such things cannot be used to construct an instance of
2158 the class unless you already have one. */
2160 else
2164 {
2167 t);
2173 }
2174 }
2175 }
2177 /* Make BINFO's vtable have N entries, including RTTI entries,
2178 vbase and vcall offsets, etc. Set its type and call the back end
2179 to lay it out. */
2181 static void
2183 {
2184 tree atype;
2185 tree vtable;
2190 /* We may have to grow the vtable. */
2193 {
2197 }
2198 }
2200 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2201 have the same signature. */
2203 int
2205 {
2206 /* One destructor overrides another if they are the same kind of
2207 destructor. */
2211 /* But a non-destructor never overrides a destructor, nor vice
2212 versa, nor do different kinds of destructors override
2213 one-another. For example, a complete object destructor does not
2214 override a deleting destructor. */
2223 {
2231 }
2233 }
2235 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2236 subobject. */
2238 static bool
2240 {
2241 tree probe;
2244 {
2248 /* If we meet a virtual base, we can't follow the inheritance
2249 any more. See if the complete type of DERIVED contains
2250 such a virtual base. */
2253 }
2255 }
2258 /* The function for which we are trying to find a final overrider. */
2259 tree fn;
2260 /* The base class in which the function was declared. */
2261 tree declaring_base;
2262 /* The candidate overriders. */
2263 tree candidates;
2264 /* Path to most derived. */
2266 };
2268 /* Add the overrider along the current path to FFOD->CANDIDATES.
2269 Returns true if an overrider was found; false otherwise. */
2271 static bool
2275 {
2276 tree method;
2278 /* If BINFO is not the most derived type, try a more derived class.
2279 A definition there will overrider a definition here. */
2281 {
2282 depth--;
2286 }
2290 {
2293 /* Remove any candidates overridden by this new function. */
2295 {
2296 /* If *CANDIDATE overrides METHOD, then METHOD
2297 cannot override anything else on the list. */
2300 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2303 else
2305 }
2307 /* Add the new function. */
2310 }
2313 }
2315 /* Called from find_final_overrider via dfs_walk. */
2317 static tree
2319 {
2327 }
2329 static tree
2331 {
2336 }
2338 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2339 FN and whose TREE_VALUE is the binfo for the base where the
2340 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2341 DERIVED) is the base object in which FN is declared. */
2343 static tree
2345 {
2346 find_final_overrider_data ffod;
2348 /* Getting this right is a little tricky. This is valid:
2350 struct S { virtual void f (); };
2351 struct T { virtual void f (); };
2352 struct U : public S, public T { };
2354 even though calling `f' in `U' is ambiguous. But,
2356 struct R { virtual void f(); };
2357 struct S : virtual public R { virtual void f (); };
2358 struct T : virtual public R { virtual void f (); };
2359 struct U : public S, public T { };
2361 is not -- there's no way to decide whether to put `S::f' or
2362 `T::f' in the vtable for `R'.
2364 The solution is to look at all paths to BINFO. If we find
2365 different overriders along any two, then there is a problem. */
2369 /* Determine the depth of the hierarchy. */
2380 /* If there was no winner, issue an error message. */
2385 }
2387 /* Return the index of the vcall offset for FN when TYPE is used as a
2388 virtual base. */
2390 static tree
2392 {
2394 tree_pair_p p;
2402 /* There should always be an appropriate index. */
2404 }
2406 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2407 dominated by T. FN is the old function; VIRTUALS points to the
2408 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2409 of that entry in the list. */
2411 static void
2414 {
2415 tree b;
2416 tree overrider;
2417 tree delta;
2418 tree virtual_base;
2419 tree first_defn;
2425 /* Find the nearest primary base (possibly binfo itself) which defines
2426 this function; this is the class the caller will convert to when
2427 calling FN through BINFO. */
2429 {
2434 /* The nearest definition is from a lost primary. */
2437 }
2440 /* Find the final overrider. */
2443 {
2446 }
2449 /* Check for adjusting covariant return types. */
2457 /* If the overrider is invalid, don't even try. */
2459 {
2460 /* If FN is a covariant thunk, we must figure out the adjustment
2461 to the final base FN was converting to. As OVERRIDER_TARGET might
2462 also be converting to the return type of FN, we have to
2463 combine the two conversions here. */
2470 {
2474 }
2475 else
2479 /* Find the equivalent binfo within the return type of the
2480 overriding function. We will want the vbase offset from
2481 there. */
2483 over_return);
2486 {
2487 /* There was no existing virtual thunk (which takes
2488 precedence). So find the binfo of the base function's
2489 return type within the overriding function's return type.
2490 Fortunately we know the covariancy is valid (it
2491 has already been checked), so we can just iterate along
2492 the binfos, which have been chained in inheritance graph
2493 order. Of course it is lame that we have to repeat the
2494 search here anyway -- we should really be caching pieces
2495 of the vtable and avoiding this repeated work. */
2498 /* Find the base binfo within the overriding function's
2499 return type. We will always find a thunk_binfo, except
2500 when the covariancy is invalid (which we will have
2501 already diagnosed). */
2504 thunk_binfo;
2510 /* See if virtual inheritance is involved. */
2512 virtual_offset;
2519 {
2523 {
2524 /* We convert via virtual base. Adjust the fixed
2525 offset to be from there. */
2526 offset =
2530 }
2532 /* There was an existing fixed offset, this must be
2533 from the base just converted to, and the base the
2534 FN was thunking to. */
2536 else
2538 }
2539 }
2542 /* Replace the overriding function with a covariant thunk. We
2543 will emit the overriding function in its own slot as
2544 well. */
2547 }
2548 else
2552 /* If we need a covariant thunk, then we may need to adjust first_defn.
2553 The ABI specifies that the thunks emitted with a function are
2554 determined by which bases the function overrides, so we need to be
2555 sure that we're using a thunk for some overridden base; even if we
2556 know that the necessary this adjustment is zero, there may not be an
2557 appropriate zero-this-adjustment thunk for us to use since thunks for
2558 overriding virtual bases always use the vcall offset.
2560 Furthermore, just choosing any base that overrides this function isn't
2561 quite right, as this slot won't be used for calls through a type that
2562 puts a covariant thunk here. Calling the function through such a type
2563 will use a different slot, and that slot is the one that determines
2564 the thunk emitted for that base.
2566 So, keep looking until we find the base that we're really overriding
2567 in this slot: the nearest primary base that doesn't use a covariant
2568 thunk in this slot. */
2570 {
2572 /* We already know that the overrider needs a covariant thunk. */
2575 {
2582 }
2584 }
2586 /* Assume that we will produce a thunk that convert all the way to
2587 the final overrider, and not to an intermediate virtual base. */
2590 /* See if we can convert to an intermediate virtual base first, and then
2591 use the vcall offset located there to finish the conversion. */
2593 {
2594 /* If we find the final overrider, then we can stop
2595 walking. */
2600 /* If we find a virtual base, and we haven't yet found the
2601 overrider, then there is a virtual base between the
2602 declaring base (first_defn) and the final overrider. */
2604 {
2607 }
2608 }
2610 /* Compute the constant adjustment to the `this' pointer. The
2611 `this' pointer, when this function is called, will point at BINFO
2612 (or one of its primary bases, which are at the same offset). */
2614 /* The `this' pointer needs to be adjusted from the declaration to
2615 the nearest virtual base. */
2620 /* If the nearest definition is in a lost primary, we don't need an
2621 entry in our vtable. Except possibly in a constructor vtable,
2622 if we happen to get our primary back. In that case, the offset
2623 will be zero, as it will be a primary base. */
2625 else
2626 /* The `this' pointer needs to be adjusted from pointing to
2627 BINFO to pointing at the base where the final overrider
2628 appears. */
2639 else
2643 }
2645 /* Called from modify_all_vtables via dfs_walk. */
2647 static tree
2649 {
2651 tree virtuals;
2652 tree old_virtuals;
2656 /* A base without a vtable needs no modification, and its bases
2657 are uninteresting. */
2662 /* Don't do the primary vtable, if it's new. */
2666 /* There's no need to modify the vtable for a non-virtual primary
2667 base; we're not going to use that vtable anyhow. We do still
2668 need to do this for virtual primary bases, as they could become
2669 non-primary in a construction vtable. */
2674 /* Now, go through each of the virtual functions in the virtual
2675 function table for BINFO. Find the final overrider, and update
2676 the BINFO_VIRTUALS list appropriately. */
2679 virtuals;
2683 binfo,
2688 }
2690 /* Update all of the primary and secondary vtables for T. Create new
2691 vtables as required, and initialize their RTTI information. Each
2692 of the functions in VIRTUALS is declared in T and may override a
2693 virtual function from a base class; find and modify the appropriate
2694 entries to point to the overriding functions. Returns a list, in
2695 declaration order, of the virtual functions that are declared in T,
2696 but do not appear in the primary base class vtable, and which
2697 should therefore be appended to the end of the vtable for T. */
2699 static tree
2701 {
2705 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2709 /* Update all of the vtables. */
2712 /* Add virtual functions not already in our primary vtable. These
2713 will be both those introduced by this class, and those overridden
2714 from secondary bases. It does not include virtuals merely
2715 inherited from secondary bases. */
2717 {
2722 {
2723 /* We don't need to adjust the `this' pointer when
2724 calling this function. */
2728 /* This is a function not already in our vtable. Keep it. */
2730 }
2731 else
2732 /* We've already got an entry for this function. Skip it. */
2734 }
2737 }
2739 /* Get the base virtual function declarations in T that have the
2740 indicated NAME. */
2742 static void
2744 {
2747 /* Find virtual functions in T with the indicated NAME. */
2749 {
2753 {
2756 }
2757 }
2764 {
2767 }
2768 }
2770 /* If this declaration supersedes the declaration of
2771 a method declared virtual in the base class, then
2772 mark this field as being virtual as well. */
2774 void
2776 {
2779 /* In [temp.mem] we have:
2781 A specialization of a member function template does not
2782 override a virtual function from a base class. */
2789 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2790 the error_mark_node so that we know it is an overriding
2791 function. */
2792 {
2799 }
2802 {
2808 }
2813 }
2815 /* Warn about hidden virtual functions that are not overridden in t.
2816 We know that constructors and destructors don't apply. */
2818 static void
2820 {
2823 {
2831 tree base_binfo;
2832 tree binfo;
2835 /* Iterate through all of the base classes looking for possibly
2836 hidden functions. */
2839 {
2842 }
2844 /* If there are no functions to hide, continue. */
2848 /* Remove any overridden functions. */
2850 {
2854 {
2855 /* If the method from the base class has the same
2856 signature as the method from the derived class, it
2857 has been overridden. */
2862 }
2863 }
2865 /* Now give a warning for all base functions without overriders,
2866 as they are hidden. */
2867 tree base_fndecl;
2870 {
2871 /* Here we know it is a hider, and no overrider exists. */
2873 OPT_Woverloaded_virtual,
2877 }
2878 }
2879 }
2881 /* Recursive helper for finish_struct_anon. */
2883 static void
2885 {
2889 {
2890 /* We're generally only interested in entities the user
2891 declared, but we also find nested classes by noticing
2892 the TYPE_DECL that we create implicitly. You're
2893 allowed to put one anonymous union inside another,
2894 though, so we explicitly tolerate that. We use
2895 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2896 we also allow unnamed types used for defining fields. */
2903 {
2904 /* We already complained about static data members in
2905 finish_static_data_member_decl. */
2907 {
2910 "%q#D invalid; an anonymous union can "
2912 else
2914 "%q#D invalid; an anonymous struct can "
2916 }
2918 }
2921 {
2923 {
2927 else
2930 }
2932 {
2936 else
2939 }
2940 }
2945 /* Recurse into the anonymous aggregates to handle correctly
2946 access control (c++/24926):
2948 class A {
2949 union {
2950 union {
2951 int i;
2952 };
2953 };
2954 };
2956 int j=A().i; */
2960 }
2961 }
2963 /* Check for things that are invalid. There are probably plenty of other
2964 things we should check for also. */
2966 static void
2968 {
2970 {
2979 }
2980 }
2982 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2983 will be used later during class template instantiation.
2984 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2985 a non-static member data (FIELD_DECL), a member function
2986 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2987 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2988 When FRIEND_P is nonzero, T is either a friend class
2989 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2990 (FUNCTION_DECL, TEMPLATE_DECL). */
2992 void
2994 {
2995 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
3000 }
3002 /* This function is called from declare_virt_assop_and_dtor via
3003 dfs_walk_all.
3005 DATA is a type that direcly or indirectly inherits the base
3006 represented by BINFO. If BINFO contains a virtual assignment [copy
3007 assignment or move assigment] operator or a virtual constructor,
3008 declare that function in DATA if it hasn't been already declared. */
3010 static tree
3012 {
3020 /* A base without a vtable needs no modification, and its bases
3021 are uninteresting. */
3025 /* If this is a primary base, then we have already looked at the
3026 virtual functions of its vtable. */
3030 {
3034 {
3039 }
3043 }
3046 }
3048 /* If the class type T has a direct or indirect base that contains a
3049 virtual assignment operator or a virtual destructor, declare that
3050 function in T if it hasn't been already declared. */
3052 static void
3054 {
3062 dfs_declare_virt_assop_and_dtor,
3064 }
3066 /* Declare the inheriting constructor for class T inherited from base
3067 constructor CTOR with the parameter array PARMS of size NPARMS. */
3069 static void
3071 {
3074 /* We don't declare an inheriting ctor that would be a default,
3075 copy or move ctor for derived or base. */
3080 {
3084 }
3093 {
3096 }
3097 }
3099 /* Declare all the inheriting constructors for class T inherited from base
3100 constructor CTOR. */
3102 static void
3104 {
3108 {
3114 }
3119 {
3123 }
3126 {
3130 }
3131 }
3133 /* Create default constructors, assignment operators, and so forth for
3134 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3135 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3136 the class cannot have a default constructor, copy constructor
3137 taking a const reference argument, or an assignment operator taking
3138 a const reference, respectively. */
3140 static void
3144 {
3145 /* Destructor. */
3147 /* In general, we create destructors lazily. */
3156 /* [class.ctor]
3158 If there is no user-declared constructor for a class, a default
3159 constructor is implicitly declared. */
3161 {
3166 /* Don't force the declaration to get a hard answer; if the
3167 definition would have made the class non-literal, it will still be
3168 non-literal because of the base or member in question, and that
3169 gives a better diagnostic. */
3171 }
3173 /* [class.ctor]
3175 If a class definition does not explicitly declare a copy
3176 constructor, one is declared implicitly. */
3178 {
3184 }
3186 /* If there is no assignment operator, one will be created if and
3187 when it is needed. For now, just record whether or not the type
3188 of the parameter to the assignment operator will be a const or
3189 non-const reference. */
3191 {
3197 }
3199 /* We can't be lazy about declaring functions that might override
3200 a virtual function from a base class. */
3204 {
3208 {
3209 /* declare, then remove the decl */
3217 }
3218 else
3220 }
3221 }
3223 /* FIELD is a bit-field. We are finishing the processing for its
3224 enclosing type. Issue any appropriate messages and set appropriate
3225 flags. Returns false if an error has been diagnosed. */
3227 static bool
3229 {
3231 tree w;
3233 /* Extract the declared width of the bitfield, which has been
3234 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3237 /* Remove the bit-field width indicator so that the rest of the
3238 compiler does not treat that value as a qualifier. */
3241 /* Detect invalid bit-field type. */
3243 {
3246 }
3247 else
3248 {
3250 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3253 /* detect invalid field size. */
3259 {
3262 }
3264 {
3267 }
3269 {
3272 }
3287 }
3290 {
3294 }
3295 else
3296 {
3297 /* Non-bit-fields are aligned for their type. */
3301 }
3302 }
3304 /* FIELD is a non bit-field. We are finishing the processing for its
3305 enclosing type T. Issue any appropriate messages and set appropriate
3306 flags. */
3308 static bool
3310 tree t,
3313 {
3317 /* In C++98 an anonymous union cannot contain any fields which would change
3318 the settings of CANT_HAVE_CONST_CTOR and friends. */
3320 ;
3321 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3322 structs. So, we recurse through their fields here. */
3324 {
3329 cant_have_const_ctor,
3330 no_const_asn_ref);
3331 }
3332 /* Check members with class type for constructors, destructors,
3333 etc. */
3335 {
3336 /* Never let anything with uninheritable virtuals
3337 make it through without complaint. */
3341 {
3346 field);
3351 field);
3353 {
3357 }
3358 }
3359 else
3360 {
3373 }
3382 }
3387 /* `build_class_init_list' does not recognize
3388 non-FIELD_DECLs. */
3392 }
3394 /* Check the data members (both static and non-static), class-scoped
3395 typedefs, etc., appearing in the declaration of T. Issue
3396 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3397 declaration order) of access declarations; each TREE_VALUE in this
3398 list is a USING_DECL.
3400 In addition, set the following flags:
3402 EMPTY_P
3403 The class is empty, i.e., contains no non-static data members.
3405 CANT_HAVE_CONST_CTOR_P
3406 This class cannot have an implicitly generated copy constructor
3407 taking a const reference.
3409 CANT_HAVE_CONST_ASN_REF
3410 This class cannot have an implicitly generated assignment
3411 operator taking a const reference.
3413 All of these flags should be initialized before calling this
3414 function.
3416 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3417 fields can be added by adding to this chain. */
3419 static void
3423 {
3431 /* Assume there are no access declarations. */
3433 /* Assume this class has no pointer members. */
3435 /* Assume none of the members of this class have default
3436 initializations. */
3440 {
3448 {
3449 /* Save the access declarations for our caller. */
3452 }
3459 /* FIXME: We should fold in the checking from check_methods. */
3462 /* If we've gotten this far, it's a data member, possibly static,
3463 or an enumerator. */
3467 /* When this goes into scope, it will be a non-local reference. */
3471 {
3472 /* [class.union] (C++98)
3474 If a union contains a static data member, or a member of
3475 reference type, the program is ill-formed.
3477 In C++11 [class.union] says:
3478 If a union contains a non-static data member of reference type
3479 the program is ill-formed. */
3481 {
3485 }
3488 {
3492 }
3493 }
3495 /* Perform error checking that did not get done in
3496 grokdeclarator. */
3498 {
3502 }
3504 {
3508 }
3516 /* Now it can only be a FIELD_DECL. */
3521 /* If at least one non-static data member is non-literal, the whole
3522 class becomes non-literal. Per Core/1453, volatile non-static
3523 data members and base classes are also not allowed.
3524 Note: if the type is incomplete we will complain later on. */
3529 /* A standard-layout class is a class that:
3530 ...
3531 has the same access control (Clause 11) for all non-static data members,
3532 ... */
3539 /* If this is of reference type, check if it needs an init. */
3541 {
3547 {
3548 /* ARM $12.6.2: [A member initializer list] (or, for an
3549 aggregate, initialization by a brace-enclosed list) is the
3550 only way to initialize nonstatic const and reference
3551 members. */
3554 }
3555 }
3560 {
3562 {
3563 warning_at
3566 x);
3568 }
3572 }
3576 /* We don't treat zero-width bitfields as making a class
3577 non-empty. */
3578 ;
3579 else
3580 {
3581 /* The class is non-empty. */
3583 /* The class is not even nearly empty. */
3585 /* If one of the data members contains an empty class,
3586 so does T. */
3590 }
3592 /* This is used by -Weffc++ (see below). Warn only for pointers
3593 to members which might hold dynamic memory. So do not warn
3594 for pointers to functions or pointers to members. */
3600 {
3605 }
3611 {
3613 {
3617 }
3619 {
3623 }
3624 }
3627 /* DR 148 now allows pointers to members (which are POD themselves),
3628 to be allowed in POD structs. */
3637 /* We set DECL_C_BIT_FIELD in grokbitfield.
3638 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3643 {
3648 }
3650 /* Now that we've removed bit-field widths from DECL_INITIAL,
3651 anything left in DECL_INITIAL is an NSDMI that makes the class
3652 non-aggregate in C++11. */
3656 /* If any field is const, the structure type is pseudo-const. */
3658 {
3663 {
3664 /* ARM $12.6.2: [A member initializer list] (or, for an
3665 aggregate, initialization by a brace-enclosed list) is the
3666 only way to initialize nonstatic const and reference
3667 members. */
3670 }
3671 }
3672 /* A field that is pseudo-const makes the structure likewise. */
3674 {
3679 }
3681 /* Core issue 80: A nonstatic data member is required to have a
3682 different name from the class iff the class has a
3683 user-declared constructor. */
3688 }
3690 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3691 it should also define a copy constructor and an assignment operator to
3692 implement the correct copy semantic (deep vs shallow, etc.). As it is
3693 not feasible to check whether the constructors do allocate dynamic memory
3694 and store it within members, we approximate the warning like this:
3696 -- Warn only if there are members which are pointers
3697 -- Warn only if there is a non-trivial constructor (otherwise,
3698 there cannot be memory allocated).
3699 -- Warn only if there is a non-trivial destructor. We assume that the
3700 user at least implemented the cleanup correctly, and a destructor
3701 is needed to free dynamic memory.
3703 This seems enough for practical purposes. */
3705 && has_pointers
3709 {
3713 {
3718 }
3722 }
3724 /* Non-static data member initializers make the default constructor
3725 non-trivial. */
3727 {
3730 }
3732 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3736 /* Check anonymous struct/anonymous union fields. */
3739 /* We've built up the list of access declarations in reverse order.
3740 Fix that now. */
3742 }
3744 /* If TYPE is an empty class type, records its OFFSET in the table of
3745 OFFSETS. */
3747 static int
3749 {
3750 splay_tree_node n;
3755 /* Record the location of this empty object in OFFSETS. */
3763 type,
3767 }
3769 /* Returns nonzero if TYPE is an empty class type and there is
3770 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3772 static int
3774 {
3775 splay_tree_node n;
3776 tree t;
3781 /* Record the location of this empty object in OFFSETS. */
3791 }
3793 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3794 F for every subobject, passing it the type, offset, and table of
3795 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3796 be traversed.
3798 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3799 than MAX_OFFSET will not be walked.
3801 If F returns a nonzero value, the traversal ceases, and that value
3802 is returned. Otherwise, returns zero. */
3804 static int
3806 subobject_offset_fn f,
3807 tree offset,
3808 splay_tree offsets,
3809 tree max_offset,
3811 {
3815 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3816 stop. */
3824 {
3827 }
3830 {
3831 tree field;
3832 tree binfo;
3835 /* Avoid recursing into objects that are not interesting. */
3839 /* Record the location of TYPE. */
3844 /* Iterate through the direct base classes of TYPE. */
3848 {
3849 tree binfo_offset;
3854 tree orig_binfo;
3855 /* We cannot rely on BINFO_OFFSET being set for the base
3856 class yet, but the offsets for direct non-virtual
3857 bases can be calculated by going back to the TYPE. */
3860 offset,
3864 f,
3865 binfo_offset,
3866 offsets,
3867 max_offset,
3871 }
3874 {
3878 /* Iterate through the virtual base classes of TYPE. In G++
3879 3.2, we included virtual bases in the direct base class
3880 loop above, which results in incorrect results; the
3881 correct offsets for virtual bases are only known when
3882 working with the most derived type. */
3886 {
3888 f,
3890 offset,
3892 offsets,
3893 max_offset,
3897 }
3898 else
3899 {
3900 /* We still have to walk the primary base, if it is
3901 virtual. (If it is non-virtual, then it was walked
3902 above.) */
3908 {
3909 r = (walk_subobject_offsets
3914 }
3915 }
3916 }
3918 /* Iterate through the fields of TYPE. */
3923 {
3924 tree field_offset;
3929 f,
3931 offset,
3932 field_offset),
3933 offsets,
3934 max_offset,
3938 }
3939 }
3941 {
3944 tree index;
3946 /* Avoid recursing into objects that are not interesting. */
3949 || !domain
3953 /* Step through each of the elements in the array. */
3957 {
3959 f,
3960 offset,
3961 offsets,
3962 max_offset,
3968 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3969 there's no point in iterating through the remaining
3970 elements of the array. */
3973 }
3974 }
3977 }
3979 /* Record all of the empty subobjects of TYPE (either a type or a
3980 binfo). If IS_DATA_MEMBER is true, then a non-static data member
3981 is being placed at OFFSET; otherwise, it is a base class that is
3982 being placed at OFFSET. */
3984 static void
3986 tree offset,
3987 splay_tree offsets,
3989 {
3990 tree max_offset;
3991 /* If recording subobjects for a non-static data member or a
3992 non-empty base class , we do not need to record offsets beyond
3993 the size of the biggest empty class. Additional data members
3994 will go at the end of the class. Additional base classes will go
3995 either at offset zero (if empty, in which case they cannot
3996 overlap with offsets past the size of the biggest empty class) or
3997 at the end of the class.
3999 However, if we are placing an empty base class, then we must record
4000 all offsets, as either the empty class is at offset zero (where
4001 other empty classes might later be placed) or at the end of the
4002 class (where other objects might then be placed, so other empty
4003 subobjects might later overlap). */
4007 else
4011 }
4013 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4014 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4015 virtual bases of TYPE are examined. */
4017 static int
4019 tree offset,
4020 splay_tree offsets,
4022 {
4023 splay_tree_node max_node;
4025 /* Get the node in OFFSETS that indicates the maximum offset where
4026 an empty subobject is located. */
4028 /* If there aren't any empty subobjects, then there's no point in
4029 performing this check. */
4035 vbases_p);
4036 }
4038 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4039 non-static data member of the type indicated by RLI. BINFO is the
4040 binfo corresponding to the base subobject, OFFSETS maps offsets to
4041 types already located at those offsets. This function determines
4042 the position of the DECL. */
4044 static void
4046 tree decl,
4047 tree binfo,
4048 splay_tree offsets)
4049 {
4052 tree type;
4055 {
4056 /* For the purposes of determining layout conflicts, we want to
4057 use the class type of BINFO; TREE_TYPE (DECL) will be the
4058 CLASSTYPE_AS_BASE version, which does not contain entries for
4059 zero-sized bases. */
4062 }
4063 else
4064 {
4067 }
4069 /* Try to place the field. It may take more than one try if we have
4070 a hard time placing the field without putting two objects of the
4071 same type at the same address. */
4073 {
4076 /* Place this field. */
4080 /* We have to check to see whether or not there is already
4081 something of the same type at the offset we're about to use.
4082 For example, consider:
4084 struct S {};
4085 struct T : public S { int i; };
4086 struct U : public S, public T {};
4088 Here, we put S at offset zero in U. Then, we can't put T at
4089 offset zero -- its S component would be at the same address
4090 as the S we already allocated. So, we have to skip ahead.
4091 Since all data members, including those whose type is an
4092 empty class, have nonzero size, any overlap can happen only
4093 with a direct or indirect base-class -- it can't happen with
4094 a data member. */
4095 /* In a union, overlap is permitted; all members are placed at
4096 offset zero. */
4101 {
4102 /* Strip off the size allocated to this field. That puts us
4103 at the first place we could have put the field with
4104 proper alignment. */
4107 /* Bump up by the alignment required for the type. */
4108 rli->bitpos
4114 }
4117 {
4118 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4119 the offset wasn't aligned like a pointer when we started to
4120 layout this field, that affects its position. */
4123 {
4126 "alignment of %qD increased in -fabi-version=9 "
4128 else
4131 }
4133 }
4134 else
4135 /* There was no conflict. We're done laying out this field. */
4137 }
4139 /* Now that we know where it will be placed, update its
4140 BINFO_OFFSET. */
4142 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4143 this point because their BINFO_OFFSET is copied from another
4144 hierarchy. Therefore, we may not need to add the entire
4145 OFFSET. */
4151 }
4153 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4155 static int
4157 tree offset,
4159 {
4161 }
4163 /* Layout the empty base BINFO. EOC indicates the byte currently just
4164 past the end of the class, and should be correctly aligned for a
4165 class of the type indicated by BINFO; OFFSETS gives the offsets of
4166 the empty bases allocated so far. T is the most derived
4167 type. Return nonzero iff we added it at the end. */
4169 static bool
4172 {
4173 tree alignment;
4177 /* This routine should only be used for empty classes. */
4182 propagate_binfo_offsets
4186 /* This is an empty base class. We first try to put it at offset
4187 zero. */
4190 offsets,
4192 {
4193 /* That didn't work. Now, we move forward from the next
4194 available spot in the class. */
4198 {
4201 offsets,
4203 /* We finally found a spot where there's no overlap. */
4206 /* There's overlap here, too. Bump along to the next spot. */
4208 }
4209 }
4212 {
4217 }
4220 }
4222 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4223 fields at NEXT_FIELD, and return it. */
4225 static tree
4227 {
4228 /* Create the FIELD_DECL. */
4242 /* Add the new FIELD_DECL to the list of fields for T. */
4248 }
4250 /* Layout the base given by BINFO in the class indicated by RLI.
4251 *BASE_ALIGN is a running maximum of the alignments of
4252 any base class. OFFSETS gives the location of empty base
4253 subobjects. T is the most derived type. Return nonzero if the new
4254 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4255 *NEXT_FIELD, unless BINFO is for an empty base class.
4257 Returns the location at which the next field should be inserted. */
4262 {
4267 /* This error is now reported in xref_tag, thus giving better
4268 location information. */
4271 /* Place the base class. */
4273 {
4274 tree decl;
4276 /* The containing class is non-empty because it has a non-empty
4277 base class. */
4280 /* Create the FIELD_DECL. */
4283 /* Try to place the field. It may take more than one try if we
4284 have a hard time placing the field without putting two
4285 objects of the same type at the same address. */
4287 }
4288 else
4289 {
4290 tree eoc;
4293 /* On some platforms (ARM), even empty classes will not be
4294 byte-aligned. */
4299 /* A nearly-empty class "has no proper base class that is empty,
4300 not morally virtual, and at an offset other than zero." */
4302 {
4305 /* The check above (used in G++ 3.2) is insufficient because
4306 an empty class placed at offset zero might itself have an
4307 empty base at a nonzero offset. */
4309 empty_base_at_nonzero_offset_p,
4310 size_zero_node,
4315 }
4317 /* We used to not create a FIELD_DECL for empty base classes because of
4318 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4319 be a problem anymore. We need them to handle initialization of C++17
4320 aggregate bases. */
4322 {
4327 }
4329 /* An empty virtual base causes a class to be non-empty
4330 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4331 here because that was already done when the virtual table
4332 pointer was created. */
4333 }
4335 /* Record the offsets of BINFO and its base subobjects. */
4338 offsets,
4342 }
4344 /* Layout all of the non-virtual base classes. Record empty
4345 subobjects in OFFSETS. T is the most derived type. Return nonzero
4346 if the type cannot be nearly empty. The fields created
4347 corresponding to the base classes will be inserted at
4348 *NEXT_FIELD. */
4350 static void
4353 {
4354 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4355 subobjects. */
4360 /* The primary base class is always allocated first. */
4365 /* Now allocate the rest of the bases. */
4367 {
4368 tree base_binfo;
4372 /* The primary base was already allocated above, so we don't
4373 need to allocate it again here. */
4377 /* Virtual bases are added at the end (a primary virtual base
4378 will have already been added). */
4384 }
4385 }
4387 /* Go through the TYPE_FIELDS of T issuing any appropriate
4388 diagnostics, figuring out which methods override which other
4389 methods, and so forth. */
4391 static void
4393 {
4396 {
4402 /* The name of the field is the original field name
4403 Save this in auxiliary field for later overloading. */
4405 {
4409 }
4411 /* All user-provided destructors are non-trivial.
4412 Constructors and assignment ops are handled in
4413 grok_special_member_properties. */
4420 "%<transaction_safe_dynamic%> may only be specified for "
4422 }
4423 }
4425 /* FN is a constructor or destructor. Clone the declaration to create
4426 a specialized in-charge or not-in-charge version, as indicated by
4427 NAME. */
4429 static tree
4431 {
4432 tree parms;
4433 tree clone;
4435 /* Copy the function. */
4437 /* Reset the function name. */
4439 /* Remember where this function came from. */
4441 /* Make it easy to find the CLONE given the FN. */
4445 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4447 {
4454 }
4455 else
4456 {
4457 // Clone constraints.
4461 }
4466 /* There's no pending inline data for this function. */
4470 /* The base-class destructor is not virtual. */
4472 {
4476 }
4482 /* If there was an in-charge parameter, drop it from the function
4483 type. */
4485 {
4486 tree basetype;
4487 tree parmtypes;
4488 tree exceptions;
4493 /* Skip the `this' parameter. */
4495 /* Skip the in-charge parameter. */
4497 /* And the VTT parm, in a complete [cd]tor. */
4502 {
4503 /* If we're omitting inherited parms, that just leaves the VTT. */
4506 }
4510 parmtypes);
4513 exceptions);
4517 }
4519 /* Copy the function parameters. */
4521 /* Remove the in-charge parameter. */
4523 {
4527 }
4528 /* And the VTT parm, in a complete [cd]tor. */
4530 {
4533 else
4534 {
4538 }
4539 }
4541 /* A base constructor inheriting from a virtual base doesn't get the
4542 arguments. */
4547 {
4550 }
4552 /* Create the RTL for this function. */
4557 }
4559 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4560 not invoke this function directly.
4562 For a non-thunk function, returns the address of the slot for storing
4563 the function it is a clone of. Otherwise returns NULL_TREE.
4565 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4566 cloned_function is unset. This is to support the separate
4567 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4568 on a template makes sense, but not the former. */
4570 tree *
4572 {
4580 {
4581 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4584 else
4585 #endif
4587 }
4592 else
4594 }
4596 /* Produce declarations for all appropriate clones of FN. If
4597 UPDATE_METHODS is true, the clones are added to the
4598 CLASSTYPE_MEMBER_VEC. */
4600 void
4602 {
4603 tree clone;
4605 /* Avoid inappropriate cloning. */
4611 {
4612 /* For each constructor, we need two variants: an in-charge version
4613 and a not-in-charge version. */
4620 }
4621 else
4622 {
4625 /* For each destructor, we need three variants: an in-charge
4626 version, a not-in-charge version, and an in-charge deleting
4627 version. We clone the deleting version first because that
4628 means it will go second on the TYPE_FIELDS list -- and that
4629 corresponds to the correct layout order in the virtual
4630 function table.
4632 For a non-virtual destructor, we do not build a deleting
4633 destructor. */
4635 {
4639 }
4646 }
4648 /* Note that this is an abstract function that is never emitted. */
4650 }
4652 /* DECL is an in charge constructor, which is being defined. This will
4653 have had an in class declaration, from whence clones were
4654 declared. An out-of-class definition can specify additional default
4655 arguments. As it is the clones that are involved in overload
4656 resolution, we must propagate the information from the DECL to its
4657 clones. */
4659 void
4661 {
4662 tree clone;
4666 {
4673 /* Skip the 'this' parameter. */
4689 {
4691 {
4695 }
4701 {
4702 /* A default parameter has been added. Adjust the
4703 clone's parameters. */
4707 tree type;
4712 {
4715 clone_parms);
4717 }
4720 clone_parms);
4729 }
4730 }
4732 }
4733 }
4735 /* For each of the constructors and destructors in T, create an
4736 in-charge and not-in-charge variant. */
4738 static void
4740 {
4741 /* While constructors can be via a using declaration, at this point
4742 we no longer need to know that. */
4748 }
4750 /* Deduce noexcept for a destructor DTOR. */
4752 void
4754 {
4757 noexcept_deferred_spec);
4758 }
4760 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4761 of TYPE for virtual functions which FNDECL overrides. Return a
4762 mask of the tm attributes found therein. */
4764 static int
4766 {
4768 tree base_binfo;
4772 {
4780 {
4784 else
4787 }
4788 else
4790 }
4793 }
4795 /* Subroutine of set_method_tm_attributes. Handle the checks and
4796 inheritance for one virtual method FNDECL. */
4798 static void
4800 {
4801 tree tm_attr;
4806 /* If FNDECL doesn't actually override anything (i.e. T is the
4807 class that first declares FNDECL virtual), then we're done. */
4814 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4815 tm_pure must match exactly, otherwise no weakening of
4816 tm_safe > tm_callable > nothing. */
4817 /* ??? The tm_pure attribute didn't make the transition to the
4818 multivendor language spec. */
4820 {
4822 {
4825 }
4826 }
4827 /* If the overridden function is tm_pure, then FNDECL must be. */
4830 /* Look for base class combinations that cannot be satisfied. */
4832 {
4838 }
4839 /* If FNDECL did not declare an attribute, then inherit the most
4840 restrictive one. */
4842 {
4844 }
4845 /* Otherwise validate that we're not weaker than a function
4846 that is being overridden. */
4847 else
4848 {
4852 }
4855 err_override:
4859 }
4861 /* For each of the methods in T, propagate a class-level tm attribute. */
4863 static void
4865 {
4868 /* Don't bother collecting tm attributes if transactional memory
4869 support is not enabled. */
4873 /* Process virtual methods first, as they inherit directly from the
4874 base virtual function and also require validation of new attributes. */
4876 {
4877 tree vchain;
4880 {
4885 }
4886 }
4888 /* If the class doesn't have an attribute, nothing more to do. */
4893 /* Any method that does not yet have a tm attribute inherits
4894 the one from the class. */
4899 }
4901 /* Returns true if FN is a default constructor. */
4903 bool
4905 {
4908 }
4910 /* Returns true iff class T has a user-defined constructor that can be called
4911 with more than zero arguments. */
4913 bool
4915 {
4920 {
4927 }
4930 }
4932 /* Returns the defaulted constructor if T has one. Otherwise, returns
4933 NULL_TREE. */
4935 tree
4937 {
4942 {
4948 }
4951 }
4953 /* Returns true iff FN is a user-provided function, i.e. user-declared
4954 and not defaulted at its first declaration. */
4956 bool
4958 {
4961 else
4965 }
4967 /* Returns true iff class T has a user-provided constructor. */
4969 bool
4971 {
4983 }
4985 /* Returns true iff class T has a user-provided or explicit constructor. */
4987 bool
4989 {
4997 {
5001 }
5004 }
5006 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5007 declared or explicitly defaulted in the class body) default
5008 constructor. */
5010 bool
5012 {
5019 {
5025 }
5028 }
5030 /* TYPE is being used as a virtual base, and has a non-trivial move
5031 assignment. Return true if this is due to there being a user-provided
5032 move assignment in TYPE or one of its subobjects; if there isn't, then
5033 multiple move assignment can't cause any harm. */
5035 bool
5037 {
5038 /* Does the type itself have a user-provided move assignment operator? */
5046 /* Do any of its bases? */
5048 tree base_binfo;
5053 /* Or non-static data members? */
5055 {
5060 }
5062 /* Seems not. */
5064 }
5066 /* If default-initialization leaves part of TYPE uninitialized, returns
5067 a DECL for the field or TYPE itself (DR 253). */
5069 tree
5071 {
5082 {
5086 }
5091 {
5095 }
5098 }
5100 /* Returns true iff for class T, a trivial synthesized default constructor
5101 would be constexpr. */
5103 bool
5105 {
5106 /* A defaulted trivial default constructor is constexpr
5107 if there is nothing to initialize. */
5110 }
5112 /* Returns true iff class T has a constexpr default constructor. */
5114 bool
5116 {
5117 tree fns;
5120 {
5121 /* The caller should have stripped an enclosing array. */
5124 }
5126 {
5129 /* Non-trivial, we need to check subobject constructors. */
5131 }
5134 }
5136 /* Returns true iff class T has a constexpr default constructor or has an
5137 implicitly declared default constructor that we can't tell if it's constexpr
5138 without forcing a lazy declaration (which might cause undesired
5139 instantiations). */
5141 bool
5143 {
5146 /* Assume it's constexpr. */
5149 }
5151 /* Returns true iff class TYPE has a virtual destructor. */
5153 bool
5155 {
5156 tree dtor;
5164 }
5166 /* Returns true iff T, a class, has a move-assignment or
5167 move-constructor. Does not lazily declare either.
5168 If USER_P is false, any move function will do. If it is true, the
5169 move function must be user-declared.
5171 Note that user-declared here is different from "user-provided",
5172 which doesn't include functions that are defaulted in the
5173 class. */
5175 bool
5177 {
5195 }
5197 /* Nonzero if we need to build up a constructor call when initializing an
5198 object of this class, either because it has a user-declared constructor
5199 or because it doesn't have a default constructor (so we need to give an
5200 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5201 what you care about is whether or not an object can be produced by a
5202 constructor (e.g. so we don't set TREE_READONLY on const variables of
5203 such type); use this function when what you care about is whether or not
5204 to try to call a constructor to create an object. The latter case is
5205 the former plus some cases of constructors that cannot be called. */
5207 bool
5209 {
5210 tree inner;
5220 /* A user-declared constructor might be private, and a constructor might
5221 be trivial but deleted. */
5224 {
5229 }
5231 }
5233 /* Like type_build_ctor_call, but for destructors. */
5235 bool
5237 {
5238 tree inner;
5247 /* A user-declared destructor might be private, and a destructor might
5248 be trivial but deleted. */
5251 {
5256 }
5258 }
5260 /* Remove all zero-width bit-fields from T. */
5262 static void
5264 {
5269 {
5272 /* We should not be confused by the fact that grokbitfield
5273 temporarily sets the width of the bit field into
5274 DECL_BIT_FIELD_REPRESENTATIVE (*fieldsp).
5275 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5276 to that width. */
5280 else
5282 }
5283 }
5285 /* Returns TRUE iff we need a cookie when dynamically allocating an
5286 array whose elements have the indicated class TYPE. */
5288 static bool
5290 {
5291 tree fns;
5296 /* If there's a non-trivial destructor, we need a cookie. In order
5297 to iterate through the array calling the destructor for each
5298 element, we'll have to know how many elements there are. */
5302 /* If the usual deallocation function is a two-argument whose second
5303 argument is of type `size_t', then we have to pass the size of
5304 the array to the deallocation function, so we will need to store
5305 a cookie. */
5309 /* If there are no `operator []' members, or the lookup is
5310 ambiguous, then we don't need a cookie. */
5313 /* Loop through all of the functions. */
5315 {
5318 /* See if this function is a one-argument delete function. If
5319 it is, then it will be the usual deallocation function. */
5323 /* Do not consider this function if its second argument is an
5324 ellipsis. */
5327 /* Otherwise, if we have a two-argument function and the second
5328 argument is `size_t', it will be the usual deallocation
5329 function -- unless there is one-argument function, too. */
5333 }
5336 }
5338 /* Finish computing the `literal type' property of class type T.
5340 At this point, we have already processed base classes and
5341 non-static data members. We need to check whether the copy
5342 constructor is trivial, the destructor is trivial, and there
5343 is a trivial default constructor or at least one constexpr
5344 constructor other than the copy constructor. */
5346 static void
5348 {
5349 tree fn;
5361 /* C++14 DR 1684 removed this restriction. */
5369 {
5373 "enclosing class of constexpr non-static member "
5376 }
5377 }
5379 /* T is a non-literal type used in a context which requires a constant
5380 expression. Explain why it isn't literal. */
5382 void
5384 {
5394 /* Already explained. */
5400 " %qT is a closure type, which is only literal in "
5408 {
5410 " %q+T is not an aggregate, does not have a trivial "
5411 "default constructor, and has no constexpr constructor that "
5414 /* Note that we can't simply call locate_ctor because when the
5415 constructor is deleted it just returns NULL_TREE. */
5417 {
5424 {
5427 else
5430 }
5431 }
5432 }
5433 else
5434 {
5438 {
5441 {
5447 }
5448 }
5450 {
5451 tree ftype;
5456 {
5459 field);
5462 }
5466 }
5467 }
5468 }
5470 /* Check the validity of the bases and members declared in T. Add any
5471 implicitly-generated functions (like copy-constructors and
5472 assignment operators). Compute various flag bits (like
5473 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5474 level: i.e., independently of the ABI in use. */
5476 static void
5478 {
5479 /* Nonzero if the implicitly generated copy constructor should take
5480 a non-const reference argument. */
5482 /* Nonzero if the implicitly generated assignment operator
5483 should take a non-const reference argument. */
5485 tree access_decls;
5488 tree fn;
5490 /* By default, we use const reference arguments and generate default
5491 constructors. */
5495 /* Check all the base-classes and set FMEM members to point to arrays
5496 of potential interest. */
5499 /* Deduce noexcept on destructor. This needs to happen after we've set
5500 triviality flags appropriately for our bases. */
5505 /* Check all the method declarations. */
5508 /* Save the initial values of these flags which only indicate whether
5509 or not the class has user-provided functions. As we analyze the
5510 bases and members we can set these flags for other reasons. */
5514 /* Check all the data member declarations. We cannot call
5515 check_field_decls until we have called check_bases check_methods,
5516 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5517 being set appropriately. */
5522 /* A nearly-empty class has to be vptr-containing; a nearly empty
5523 class contains just a vptr. */
5527 /* Do some bookkeeping that will guide the generation of implicitly
5528 declared member functions. */
5531 /* We need to call a constructor for this class if it has a
5532 user-provided constructor, or if the default constructor is going
5533 to initialize the vptr. (This is not an if-and-only-if;
5534 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5535 themselves need constructing.) */
5538 /* [dcl.init.aggr]
5540 An aggregate is an array or a class with no user-provided
5541 constructors ... and no virtual functions.
5543 Again, other conditions for being an aggregate are checked
5544 elsewhere. */
5548 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5549 retain the old definition internally for ABI reasons. */
5558 /* If the only explicitly declared default constructor is user-provided,
5559 set TYPE_HAS_COMPLEX_DFLT. */
5565 /* Warn if a public base of a polymorphic type has an accessible
5566 non-virtual destructor. It is only now that we know the class is
5567 polymorphic. Although a polymorphic base will have a already
5568 been diagnosed during its definition, we warn on use too. */
5570 {
5573 tree base_binfo;
5577 {
5585 basetype);
5586 }
5587 }
5589 /* If the class has no user-declared constructor, but does have
5590 non-static const or reference data members that can never be
5591 initialized, issue a warning. */
5593 /* Classes with user-declared constructors are presumed to
5594 initialize these members. */
5596 /* Aggregates can be initialized with brace-enclosed
5597 initializers. */
5599 {
5600 tree field;
5603 {
5604 tree type;
5621 }
5622 }
5624 /* Synthesize any needed methods. */
5626 cant_have_const_ctor,
5627 no_const_asn_ref);
5629 /* Check defaulted declarations here so we have cant_have_const_ctor
5630 and don't need to worry about clones. */
5635 {
5638 {
5639 bool imp_const_p
5645 /* If the function is defaulted outside the class, we just
5646 give the synthesis error. */
5649 }
5651 }
5654 {
5655 /* "This class type is not an aggregate." */
5657 }
5659 /* Compute the 'literal type' property before we
5660 do anything with non-static member functions. */
5663 /* Create the in-charge and not-in-charge variants of constructors
5664 and destructors. */
5667 /* Process the using-declarations. */
5671 /* Figure out whether or not we will need a cookie when dynamically
5672 allocating an array of this type. */
5675 }
5677 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5678 accordingly. If a new vfield was created (because T doesn't have a
5679 primary base class), then the newly created field is returned. It
5680 is not added to the TYPE_FIELDS list; it is the caller's
5681 responsibility to do that. Accumulate declared virtual functions
5682 on VIRTUALS_P. */
5684 static tree
5686 {
5687 tree fn;
5689 /* Collect the virtual functions declared in T. */
5694 {
5703 }
5705 /* If we couldn't find an appropriate base class, create a new field
5706 here. Even if there weren't any new virtual functions, we might need a
5707 new virtual function table if we're supposed to include vptrs in
5708 all classes that need them. */
5710 {
5711 /* We build this decl with vtbl_ptr_type_node, which is a
5712 `vtable_entry_type*'. It might seem more precise to use
5713 `vtable_entry_type (*)[N]' where N is the number of virtual
5714 functions. However, that would require the vtable pointer in
5715 base classes to have a different type than the vtable pointer
5716 in derived classes. We could make that happen, but that
5717 still wouldn't solve all the problems. In particular, the
5718 type-based alias analysis code would decide that assignments
5719 to the base class vtable pointer can't alias assignments to
5720 the derived class vtable pointer, since they have different
5721 types. Thus, in a derived class destructor, where the base
5722 class constructor was inlined, we could generate bad code for
5723 setting up the vtable pointer.
5725 Therefore, we use one type for all vtable pointers. We still
5726 use a type-correct type; it's just doesn't indicate the array
5727 bounds. That's better than using `void*' or some such; it's
5728 cleaner, and it let's the alias analysis code know that these
5729 stores cannot alias stores to void*! */
5730 tree field;
5743 /* This class is non-empty. */
5747 }
5750 }
5752 /* Add OFFSET to all base types of BINFO which is a base in the
5753 hierarchy dominated by T.
5755 OFFSET, which is a type offset, is number of bytes. */
5757 static void
5759 {
5761 tree primary_binfo;
5762 tree base_binfo;
5764 /* Update BINFO's offset. */
5769 offset));
5771 /* Find the primary base class. */
5777 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5778 downwards. */
5780 {
5781 /* Don't do the primary base twice. */
5789 }
5790 }
5792 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5793 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5794 empty subobjects of T. */
5796 static void
5798 {
5799 tree vbase;
5806 /* Find the last field. The artificial fields created for virtual
5807 bases will go after the last extant field to date. */
5812 /* Go through the virtual bases, allocating space for each virtual
5813 base that is not already a primary base class. These are
5814 allocated in inheritance graph order. */
5816 {
5821 {
5822 /* This virtual base is not a primary base of any class in the
5823 hierarchy, so we have to add space for it. */
5826 }
5827 }
5828 }
5830 /* Returns the offset of the byte just past the end of the base class
5831 BINFO. */
5833 static tree
5835 {
5836 tree size;
5841 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5842 allocate some space for it. It cannot have virtual bases, so
5843 TYPE_SIZE_UNIT is fine. */
5845 else
5849 }
5851 /* Returns the offset of the byte just past the end of the base class
5852 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
5853 only non-virtual bases are included. */
5855 static tree
5857 {
5860 tree binfo;
5861 tree base_binfo;
5862 tree offset;
5867 {
5877 }
5882 {
5886 }
5889 }
5891 /* Warn about bases of T that are inaccessible because they are
5892 ambiguous. For example:
5894 struct S {};
5895 struct T : public S {};
5896 struct U : public S, public T {};
5898 Here, `(S*) new U' is not allowed because there are two `S'
5899 subobjects of U. */
5901 static void
5903 {
5906 tree basetype;
5907 tree binfo;
5908 tree base_binfo;
5910 /* If there are no repeated bases, nothing can be ambiguous. */
5914 /* Check direct bases. */
5917 {
5923 }
5925 /* Check for ambiguous virtual bases. */
5929 {
5935 }
5936 }
5938 /* Compare two INTEGER_CSTs K1 and K2. */
5940 static int
5942 {
5944 }
5946 /* Increase the size indicated in RLI to account for empty classes
5947 that are "off the end" of the class. */
5949 static void
5951 {
5952 tree eoc;
5953 tree rli_size;
5955 /* It might be the case that we grew the class to allocate a
5956 zero-sized base class. That won't be reflected in RLI, yet,
5957 because we are willing to overlay multiple bases at the same
5958 offset. However, now we need to make sure that RLI is big enough
5959 to reflect the entire class. */
5964 {
5965 /* The size should have been rounded to a whole byte. */
5968 rli->bitpos
5977 }
5978 }
5980 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
5981 BINFO_OFFSETs for all of the base-classes. Position the vtable
5982 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
5984 static void
5986 {
5987 tree non_static_data_members;
5988 tree field;
5989 tree vptr;
5990 record_layout_info rli;
5991 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
5992 types that appear at that offset. */
5993 splay_tree empty_base_offsets;
5994 /* True if the last field laid out was a bit-field. */
5996 /* The location at which the next field should be inserted. */
5999 /* Keep track of the first non-static data member. */
6002 /* Start laying out the record. */
6005 /* Mark all the primary bases in the hierarchy. */
6008 /* Create a pointer to our virtual function table. */
6011 /* The vptr is always the first thing in the class. */
6013 {
6018 }
6019 else
6022 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6027 /* Layout the non-static data members. */
6029 {
6030 tree type;
6031 tree padding;
6033 /* We still pass things that aren't non-static data members to
6034 the back end, in case it wants to do something with them. */
6036 {
6038 /* If the static data member has incomplete type, keep track
6039 of it so that it can be completed later. (The handling
6040 of pending statics in finish_record_layout is
6041 insufficient; consider:
6043 struct S1;
6044 struct S2 { static S1 s1; };
6046 At this point, finish_record_layout will be called, but
6047 S1 is still incomplete.) */
6049 {
6051 /* The visibility of static data members is determined
6052 at their point of declaration, not their point of
6053 definition. */
6055 }
6057 }
6065 /* If this field is a bit-field whose width is greater than its
6066 type, then there are some special rules for allocating
6067 it. */
6070 {
6072 /* We must allocate the bits as if suitably aligned for the
6073 longest integer type that fits in this many bits. Then,
6074 we are supposed to use the left over bits as additional
6075 padding. */
6077 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6085 {
6087 /* Too big, so our current guess is what we want. */
6089 /* Not bigger than limit, ok */
6091 }
6093 /* Figure out how much additional padding is required. */
6095 /* In a union, the padding field must have the full width
6096 of the bit-field; all fields start at offset zero. */
6098 else
6105 /* An unnamed bitfield does not normally affect the
6106 alignment of the containing class on a target where
6107 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6108 make any exceptions for unnamed bitfields when the
6109 bitfields are longer than their types. Therefore, we
6110 temporarily give the field a name. */
6112 {
6115 }
6121 empty_base_offsets);
6124 /* Now that layout has been performed, set the size of the
6125 field to the size of its declared type; the rest of the
6126 field is effectively invisible. */
6128 /* We must also reset the DECL_MODE of the field. */
6130 }
6131 else
6133 empty_base_offsets);
6135 /* Remember the location of any empty classes in FIELD. */
6138 empty_base_offsets,
6141 /* If a bit-field does not immediately follow another bit-field,
6142 and yet it starts in the middle of a byte, we have failed to
6143 comply with the ABI. */
6146 /* The TREE_NO_WARNING flag gets set by Objective-C when
6147 laying out an Objective-C class. The ObjC ABI differs
6148 from the C++ ABI, and so we do not want a warning
6149 here. */
6151 && !last_field_was_bitfield
6154 bitsize_unit_node)))
6156 "offset of %qD is not ABI-compliant and may "
6159 /* The middle end uses the type of expressions to determine the
6160 possible range of expression values. In order to optimize
6161 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6162 must be made aware of the width of "i", via its type.
6164 Because C++ does not have integer types of arbitrary width,
6165 we must (for the purposes of the front end) convert from the
6166 type assigned here to the declared type of the bitfield
6167 whenever a bitfield expression is used as an rvalue.
6168 Similarly, when assigning a value to a bitfield, the value
6169 must be converted to the type given the bitfield here. */
6171 {
6176 {
6183 }
6184 }
6186 /* If we needed additional padding after this field, add it
6187 now. */
6189 {
6190 tree padding_field;
6193 FIELD_DECL,
6194 NULL_TREE,
6195 char_type_node);
6202 NULL_TREE,
6203 empty_base_offsets);
6204 }
6207 }
6210 {
6211 /* Make sure that we are on a byte boundary so that the size of
6212 the class without virtual bases will always be a round number
6213 of bytes. */
6216 }
6218 /* Delete all zero-width bit-fields from the list of fields. Now
6219 that the type is laid out they are no longer important. */
6223 {
6224 /* T needs a different layout as a base (eliding virtual bases
6225 or whatever). Create that version. */
6228 /* If the ABI version is not at least two, and the last
6229 field was a bit-field, RLI may not be on a byte
6230 boundary. In particular, rli_size_unit_so_far might
6231 indicate the last complete byte, while rli_size_so_far
6232 indicates the total number of bits used. Therefore,
6233 rli_size_so_far, rather than rli_size_unit_so_far, is
6234 used to compute TYPE_SIZE_UNIT. */
6242 eoc);
6252 /* Copy the non-static data members of T. This will include its
6253 direct non-virtual bases & vtable. */
6257 {
6261 }
6264 /* We use the base type for trivial assignments, and hence it
6265 needs a mode. */
6270 /* Record the base version of the type. */
6272 }
6273 else
6276 /* Every empty class contains an empty class. */
6280 /* Set the TYPE_DECL for this type to contain the right
6281 value for DECL_OFFSET, so that we can use it as part
6282 of a COMPONENT_REF for multiple inheritance. */
6285 /* Now fix up any virtual base class types that we left lying
6286 around. We must get these done before we try to lay out the
6287 virtual function table. As a side-effect, this will remove the
6288 base subobject fields. */
6291 /* Make sure that empty classes are reflected in RLI at this
6292 point. */
6295 /* Make sure not to create any structures with zero size. */
6301 /* If this is a non-POD, declaring it packed makes a difference to how it
6302 can be used as a field; don't let finalize_record_size undo it. */
6306 /* Let the back end lay out the type. */
6315 /* Warn about bases that can't be talked about due to ambiguity. */
6318 /* Now that we're done with layout, give the base fields the real types. */
6323 /* Clean up. */
6330 }
6332 /* Determine the "key method" for the class type indicated by TYPE,
6333 and set CLASSTYPE_KEY_METHOD accordingly. */
6335 void
6337 {
6338 tree method;
6345 /* The key method is the first non-pure virtual function that is not
6346 inline at the point of class definition. On some targets the
6347 key function may not be inline; those targets should not call
6348 this function until the end of the translation unit. */
6354 {
6357 }
6360 }
6362 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6363 class data member of non-zero size, otherwise false. */
6367 {
6375 {
6379 }
6382 }
6384 /* Used by find_flexarrays and related functions. */
6386 struct flexmems_t
6387 {
6388 /* The first flexible array member or non-zero array member found
6389 in the order of layout. */
6390 tree array;
6391 /* First non-static non-empty data member in the class or its bases. */
6392 tree first;
6393 /* The first non-static non-empty data member following either
6394 the flexible array member, if found, or the zero-length array member
6395 otherwise. AFTER[1] refers to the first such data member of a union
6396 of which the struct containing the flexible array member or zero-length
6397 array is a member, or NULL when no such union exists. This element is
6398 only used during searching, not for diagnosing problems. AFTER[0]
6399 refers to the first such data member that is not a member of such
6400 a union. */
6403 /* Refers to a struct (not union) in which the struct of which the flexible
6404 array is member is defined. Used to diagnose strictly (according to C)
6405 invalid uses of the latter structs. */
6406 tree enclosing;
6407 };
6409 /* Find either the first flexible array member or the first zero-length
6410 array, in that order of preference, among members of class T (but not
6411 its base classes), and set members of FMEM accordingly.
6412 BASE_P is true if T is a base class of another class.
6413 PUN is set to the outermost union in which the flexible array member
6414 (or zero-length array) is defined if one such union exists, otherwise
6415 to NULL.
6416 Similarly, PSTR is set to a data member of the outermost struct of
6417 which the flexible array is a member if one such struct exists,
6418 otherwise to NULL. */
6420 static void
6424 {
6425 /* Set the "pointer" to the outermost enclosing union if not set
6426 yet and maintain it for the remainder of the recursion. */
6431 {
6435 /* Is FLD a typedef for an anonymous struct? */
6437 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6438 handled elsewhere so that errors like the following are detected
6439 as well:
6440 typedef struct { int i, a[], j; } S; // bug c++/72753
6441 S s [2]; // bug c++/68489
6442 */
6447 {
6448 /* Check the nested unnamed type referenced via a typedef
6449 independently of FMEM (since it's not a data member of
6450 the enclosing class). */
6453 }
6455 /* Skip anything that's GCC-generated or not a (non-static) data
6456 member. */
6460 /* Type of the member. */
6465 /* Determine the type of the array element or object referenced
6466 by the member so that it can be checked for flexible array
6467 members if it hasn't been yet. */
6475 {
6477 {
6478 /* Once the member after the flexible array has been found
6479 we're done. */
6482 }
6485 {
6486 /* Descend into the non-static member struct or union and try
6487 to find a flexible array member or zero-length array among
6488 its members. This is only necessary for anonymous types
6489 and types in whose context the current type T has not been
6490 defined (the latter must not be checked again because they
6491 are already in the process of being checked by one of the
6492 recursive calls). */
6497 /* If this member isn't anonymous and a prior non-flexible array
6498 member has been seen in one of the enclosing structs, clear
6499 the FIRST member since it doesn't contribute to the flexible
6500 array struct's members. */
6511 {
6512 /* Restore the FIRST member reset above if no flexible
6513 array member has been found in this member's struct. */
6515 }
6517 /* If the member struct contains the first flexible array
6518 member, or if this member is a base class, continue to
6519 the next member and avoid setting the FMEM->NEXT pointer
6520 to point to it. */
6523 }
6524 }
6527 {
6528 /* Remember the first non-static data member. */
6532 /* Remember the first non-static data member after the flexible
6533 array member, if one has been found, or the zero-length array
6534 if it has been found. */
6537 }
6539 /* Skip non-arrays. */
6543 /* Determine the upper bound of the array if it has one. */
6545 {
6547 {
6548 /* Make a record of the zero-length array if either one
6549 such field or a flexible array member has been seen to
6550 handle the pathological and unlikely case of multiple
6551 such members. */
6554 }
6556 {
6557 /* Remember the first zero-length array unless a flexible array
6558 member has already been seen. */
6561 }
6562 }
6563 else
6564 {
6565 /* Flexible array members have no upper bound. */
6567 {
6568 /* Replace the zero-length array if it's been stored and
6569 reset the after pointer. */
6571 {
6575 }
6576 }
6577 else
6578 {
6581 }
6582 }
6583 }
6584 }
6586 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6587 a flexible array member (or the zero-length array extension). */
6589 static void
6591 {
6603 }
6605 /* Issue diagnostics for invalid flexible array members or zero-length
6606 arrays that are not the last elements of the containing class or its
6607 base classes or that are its sole members. */
6609 static void
6611 {
6616 {
6619 }
6621 /* Has a diagnostic been issued? */
6627 {
6634 {
6638 {
6641 }
6642 }
6643 }
6644 else
6645 {
6652 {
6658 /* In the unlikely event that the member following the flexible
6659 array member is declared in a different class, or the member
6660 overlaps another member of a common union, point to it.
6661 Otherwise it should be obvious. */
6665 {
6670 }
6671 }
6672 }
6676 }
6679 /* Recursively check to make sure that any flexible array or zero-length
6680 array members of class T or its bases are valid (i.e., not the sole
6681 non-static data member of T and, if one exists, that it is the last
6682 non-static data member of T and its base classes. FMEM is expected
6683 to be initially null and is used internally by recursive calls to
6684 the function. Issue the appropriate diagnostics for the array member
6685 that fails the checks. */
6687 static void
6690 {
6691 /* Initialize the result of a search for flexible array and zero-length
6692 array members. Avoid doing any work if the most interesting FMEM data
6693 have already been populated. */
6702 /* Recursively check the primary base class first. */
6704 {
6707 }
6709 /* Recursively check the base classes. */
6712 {
6715 /* The primary base class was already checked above. */
6719 /* Virtual base classes are at the end. */
6723 /* Check the base class. */
6725 }
6728 {
6729 /* Check virtual base classes only once per derived class.
6730 I.e., this check is not performed recursively for base
6731 classes. */
6733 tree base_binfo;
6737 {
6738 /* Check the virtual base class. */
6742 }
6743 }
6745 /* Is the type unnamed (and therefore a member of it potentially
6746 an anonymous struct or union)? */
6749 /* Search the members of the current (possibly derived) class, skipping
6750 unnamed structs and unions since those could be anonymous. */
6755 {
6756 /* Issue diagnostics for invalid flexible and zero-length array
6757 members found in base classes or among the members of the current
6758 class. Ignore anonymous structs and unions whose members are
6759 considered to be members of the enclosing class and thus will
6760 be diagnosed when checking it. */
6762 }
6763 }
6765 /* Perform processing required when the definition of T (a class type)
6766 is complete. Diagnose invalid definitions of flexible array members
6767 and zero-size arrays. */
6769 void
6771 {
6772 tree x;
6773 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6777 {
6782 }
6784 /* If this type was previously laid out as a forward reference,
6785 make sure we lay it out again. */
6789 /* Make assumptions about the class; we'll reset the flags if
6790 necessary. */
6796 /* Do end-of-class semantic processing: checking the validity of the
6797 bases and members and add implicitly generated methods. */
6800 /* Find the key method. */
6802 {
6803 /* The Itanium C++ ABI permits the key method to be chosen when
6804 the class is defined -- even though the key method so
6805 selected may later turn out to be an inline function. On
6806 some systems (such as ARM Symbian OS) the key method cannot
6807 be determined until the end of the translation unit. On such
6808 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6809 will cause the class to be added to KEYED_CLASSES. Then, in
6810 finish_file we will determine the key method. */
6814 /* If a polymorphic class has no key method, we may emit the vtable
6815 in every translation unit where the class definition appears. If
6816 we're devirtualizing, we can look into the vtable even if we
6817 aren't emitting it. */
6820 }
6822 /* Layout the class itself. */
6824 /* COMPLETE_TYPE_P is now true. */
6828 /* With the layout complete, check for flexible array members and
6829 zero-length arrays that might overlap other members in the final
6830 layout. */
6835 /* If necessary, create the primary vtable for this class. */
6837 {
6838 /* We must enter these virtuals into the table. */
6842 /* Here we know enough to change the type of our virtual
6843 function table, but we will wait until later this function. */
6846 /* If we're warning about ABI tags, check the types of the new
6847 virtual functions. */
6851 }
6854 {
6856 tree fn;
6863 /* Add entries for virtual functions introduced by this class. */
6867 /* Set DECL_VINDEX for all functions declared in this class. */
6869 fn;
6871 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6873 {
6877 /* A thunk. We should never be calling this entry directly
6878 from this vtable -- we'd use the entry for the non
6879 thunk base function. */
6883 }
6884 }
6892 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
6893 for any static member objects of the type we're working on. */
6902 /* Complain if one of the field types requires lower visibility. */
6905 /* Make the rtl for any new vtables we have created, and unmark
6906 the base types we marked. */
6909 /* Build the VTT for T. */
6916 "%q#T has virtual functions and accessible"
6924 /* Class layout, assignment of virtual table slots, etc., is now
6925 complete. Give the back end a chance to tweak the visibility of
6926 the class or perform any other required target modifications. */
6936 /* Finish debugging output for this type. */
6940 {
6943 {
6946 }
6948 {
6951 else
6952 {
6955 }
6957 }
6959 {
6961 "the type of the first field has a different ABI from the "
6964 }
6965 }
6966 }
6968 /* When T was built up, the member declarations were added in reverse
6969 order. Rearrange them to declaration order. */
6971 void
6973 {
6974 tree next;
6975 tree prev;
6976 tree x;
6978 /* The following lists are all in reverse order. Put them in
6979 declaration order now. */
6982 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
6983 order, so we can't just use nreverse. Due to stat_hack
6984 chicanery in finish_member_declaration. */
6989 {
6993 }
6996 {
6999 }
7000 }
7002 tree
7004 {
7007 /* Now that we've got all the field declarations, reverse everything
7008 as necessary. */
7014 /* Nadger the current location so that diagnostics point to the start of
7015 the struct, not the end. */
7019 {
7020 tree x;
7022 /* We need to add the target functions of USING_DECLS, so that
7023 they can be found when the using declaration is not
7024 instantiated yet. */
7027 {
7032 }
7038 /* COMPLETE_TYPE_P is now true. */
7042 /* We need to emit an error message if this type was used as a parameter
7043 and it is an abstract type, even if it is a template. We construct
7044 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7045 account and we call complete_vars with this type, which will check
7046 the PARM_DECLS. Note that while the type is being defined,
7047 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7048 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7055 /* Remember current #pragma pack value. */
7058 /* Fix up any variants we've already built. */
7060 {
7064 }
7065 }
7066 else
7068 /* COMPLETE_TYPE_P is now true. */
7073 {
7074 /* People keep complaining that the compiler crashes on an invalid
7075 definition of initializer_list, so I guess we should explicitly
7076 reject it. What the compiler internals care about is that it's a
7077 template and has a pointer field followed by an integer field. */
7080 {
7083 {
7087 }
7088 }
7091 "definition of std::initializer_list does not match "
7093 }
7101 else
7105 /* Lambdas are defined by the LAMBDA_EXPR. */
7110 }
7111 \f
7112 /* Hash table to avoid endless recursion when handling references. */
7115 /* Return the dynamic type of INSTANCE, if known.
7116 Used to determine whether the virtual function table is needed
7117 or not.
7119 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7120 of our knowledge of its type. *NONNULL should be initialized
7121 before this function is called. */
7123 static tree
7125 {
7126 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7129 {
7133 else
7137 /* This is a call to a constructor, hence it's never zero. */
7139 {
7143 }
7147 /* This is a call to a constructor, hence it's never zero. */
7149 {
7153 }
7162 /* Propagate nonnull. */
7167 CASE_CONVERT:
7173 {
7174 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7175 with a real object -- given &p->f, p can still be null. */
7177 /* ??? Probably should check DECL_WEAK here. */
7180 }
7184 /* If this component is really a base class reference, then the field
7185 itself isn't definitive. */
7194 {
7198 }
7199 /* fall through. */
7204 {
7208 }
7210 {
7214 /* if we're in a ctor or dtor, we know our type. If
7215 current_class_ptr is set but we aren't in a function, we're in
7216 an NSDMI (and therefore a constructor). */
7221 {
7225 }
7226 }
7228 {
7229 /* We only need one hash table because it is always left empty. */
7231 fixed_type_or_null_ref_ht
7234 /* Reference variables should be references to objects. */
7238 /* Enter the INSTANCE in a table to prevent recursion; a
7239 variable's initializer may refer to the variable
7240 itself. */
7245 {
7246 tree type;
7255 }
7256 }
7261 }
7262 #undef RECUR
7263 }
7265 /* Return nonzero if the dynamic type of INSTANCE is known, and
7266 equivalent to the static type. We also handle the case where
7267 INSTANCE is really a pointer. Return negative if this is a
7268 ctor/dtor. There the dynamic type is known, but this might not be
7269 the most derived base of the original object, and hence virtual
7270 bases may not be laid out according to this type.
7272 Used to determine whether the virtual function table is needed
7273 or not.
7275 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7276 of our knowledge of its type. *NONNULL should be initialized
7277 before this function is called. */
7279 int
7281 {
7284 tree fixed;
7286 /* processing_template_decl can be false in a template if we're in
7287 instantiate_non_dependent_expr, but we still want to suppress
7288 this check. */
7290 {
7291 /* In a template we only care about the type of the result. */
7295 }
7305 }
7307 \f
7308 void
7310 {
7313 current_class_stack
7321 }
7323 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7325 static void
7327 {
7328 tree type;
7330 /* We are re-entering the same class we just left, so we don't
7331 have to search the whole inheritance matrix to find all the
7332 decls to bind again. Instead, we install the cached
7333 class_shadowed list and walk through it binding names. */
7336 /* Restore IDENTIFIER_TYPE_VALUE. */
7338 type;
7341 }
7343 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7344 appropriate for TYPE.
7346 So that we may avoid calls to lookup_name, we cache the _TYPE
7347 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7349 For multiple inheritance, we perform a two-pass depth-first search
7350 of the type lattice. */
7352 void
7354 {
7355 class_stack_node_t csn;
7359 /* Make sure there is enough room for the new entry on the stack. */
7361 {
7363 current_class_stack
7365 current_class_stack_size);
7366 }
7368 /* Insert a new entry on the class stack. */
7375 current_class_depth++;
7377 /* Now set up the new type. */
7383 /* By default, things in classes are private, while things in
7384 structures or unions are public. */
7386 ? access_private_node
7392 {
7393 /* Forcibly remove any old class remnants. */
7395 }
7401 else
7403 }
7405 /* When we exit a toplevel class scope, we save its binding level so
7406 that we can restore it quickly. Here, we've entered some other
7407 class, so we must invalidate our cache. */
7409 void
7411 {
7413 }
7415 /* Get out of the current class scope. If we were in a class scope
7416 previously, that is the one popped to. */
7418 void
7420 {
7423 current_class_depth--;
7429 }
7431 /* Mark the top of the class stack as hidden. */
7433 void
7435 {
7438 }
7440 /* Mark the top of the class stack as un-hidden. */
7442 void
7444 {
7447 }
7449 /* Returns 1 if the class type currently being defined is either T or
7450 a nested type of T. Returns the type from the current_class_stack,
7451 which might be equivalent to but not equal to T in case of
7452 constrained partial specializations. */
7454 tree
7456 {
7464 /* We start looking from 1 because entry 0 is from global scope,
7465 and has no type. */
7467 {
7468 tree c;
7471 else
7472 {
7476 }
7481 }
7483 }
7485 /* If either current_class_type or one of its enclosing classes are derived
7486 from T, return the appropriate type. Used to determine how we found
7487 something via unqualified lookup. */
7489 tree
7491 {
7494 /* The bases of a dependent type are unknown. */
7505 {
7510 }
7513 }
7515 /* Return the outermost enclosing class type that is still open, or
7516 NULL_TREE. */
7518 tree
7520 {
7527 {
7534 }
7536 }
7538 /* Returns the innermost class type which is not a lambda closure type. */
7540 tree
7542 {
7547 }
7549 /* When entering a class scope, all enclosing class scopes' names with
7550 static meaning (static variables, static functions, types and
7551 enumerators) have to be visible. This recursive function calls
7552 pushclass for all enclosing class contexts until global or a local
7553 scope is reached. TYPE is the enclosed class. */
7555 void
7557 {
7558 /* A namespace might be passed in error cases, like A::B:C. */
7566 }
7568 /* Undoes a push_nested_class call. */
7570 void
7572 {
7578 }
7580 /* Returns the number of extern "LANG" blocks we are nested within. */
7582 int
7584 {
7586 }
7588 /* Set global variables CURRENT_LANG_NAME to appropriate value
7589 so that behavior of name-mangling machinery is correct. */
7591 void
7593 {
7600 else
7602 }
7604 /* Get out of the current language scope. */
7606 void
7608 {
7610 }
7611 \f
7612 /* Type instantiation routines. */
7614 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7615 matches the TARGET_TYPE. If there is no satisfactory match, return
7616 error_mark_node, and issue an error & warning messages under
7617 control of FLAGS. Permit pointers to member function if FLAGS
7618 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7619 a template-id, and EXPLICIT_TARGS are the explicitly provided
7620 template arguments.
7622 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7623 is the base path used to reference those member functions. If
7624 the address is resolved to a member function, access checks will be
7625 performed and errors issued if appropriate. */
7627 static tree
7629 tree overload,
7630 tsubst_flags_t complain,
7632 tree explicit_targs,
7633 tree access_path)
7634 {
7635 /* Here's what the standard says:
7637 [over.over]
7639 If the name is a function template, template argument deduction
7640 is done, and if the argument deduction succeeds, the deduced
7641 arguments are used to generate a single template function, which
7642 is added to the set of overloaded functions considered.
7644 Non-member functions and static member functions match targets of
7645 type "pointer-to-function" or "reference-to-function." Nonstatic
7646 member functions match targets of type "pointer-to-member
7647 function;" the function type of the pointer to member is used to
7648 select the member function from the set of overloaded member
7649 functions. If a nonstatic member function is selected, the
7650 reference to the overloaded function name is required to have the
7651 form of a pointer to member as described in 5.3.1.
7653 If more than one function is selected, any template functions in
7654 the set are eliminated if the set also contains a non-template
7655 function, and any given template function is eliminated if the
7656 set contains a second template function that is more specialized
7657 than the first according to the partial ordering rules 14.5.5.2.
7658 After such eliminations, if any, there shall remain exactly one
7659 selected function. */
7662 /* We store the matches in a TREE_LIST rooted here. The functions
7663 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7664 interoperability with most_specialized_instantiation. */
7666 tree fn;
7667 tree target_fn_type;
7669 /* By the time we get here, we should be seeing only real
7670 pointer-to-member types, not the internal POINTER_TYPE to
7671 METHOD_TYPE representation. */
7677 /* Check that the TARGET_TYPE is reasonable. */
7682 /* This is OK, too. */
7685 /* This is OK, too. This comes from a conversion to reference
7686 type. */
7688 else
7689 {
7695 }
7697 /* Non-member functions and static member functions match targets of type
7698 "pointer-to-function" or "reference-to-function." Nonstatic member
7699 functions match targets of type "pointer-to-member-function;" the
7700 function type of the pointer to member is used to select the member
7701 function from the set of overloaded member functions.
7703 So figure out the FUNCTION_TYPE that we want to match against. */
7706 /* If we can find a non-template function that matches, we can just
7707 use it. There's no point in generating template instantiations
7708 if we're just going to throw them out anyhow. But, of course, we
7709 can only do this when we don't *need* a template function. */
7712 {
7716 /* We're not looking for templates just yet. */
7720 /* We're looking for a non-static member, and this isn't
7721 one, or vice versa. */
7724 /* In C++17 we need the noexcept-qualifier to compare types. */
7729 /* See if there's a match. */
7734 }
7736 /* Now, if we've already got a match (or matches), there's no need
7737 to proceed to the template functions. But, if we don't have a
7738 match we need to look at them, too. */
7740 {
7741 tree target_arg_types;
7742 tree target_ret_type;
7745 tree arg;
7759 {
7761 tree instantiation;
7762 tree targs;
7765 /* We're only looking for templates. */
7770 /* We're not looking for a non-static member, and this is
7771 one, or vice versa. */
7776 /* If the template has a deduced return type, don't expose it to
7777 template argument deduction. */
7781 /* Try to do argument deduction. */
7788 /* Instantiation failed. */
7791 /* Constraints must be satisfied. This is done before
7792 return type deduction since that instantiates the
7793 function. */
7797 /* And now force instantiation to do return type deduction. */
7799 {
7805 }
7807 /* In C++17 we need the noexcept-qualifier to compare types. */
7811 /* See if there's a match. */
7816 }
7818 /* Now, remove all but the most specialized of the matches. */
7820 {
7825 NULL_TREE,
7826 NULL_TREE);
7827 }
7828 }
7830 /* Now we should have exactly one function in MATCHES. */
7832 {
7833 /* There were *no* matches. */
7835 {
7840 }
7842 }
7844 {
7845 /* There were too many matches. First check if they're all
7846 the same function. */
7851 /* For multi-versioned functions, more than one match is just fine and
7852 decls_match will return false as they are different. */
7860 {
7862 {
7866 /* Since print_candidates expects the functions in the
7867 TREE_VALUE slot, we flip them here. */
7872 }
7875 }
7876 }
7878 /* Good, exactly one match. Now, convert it to the correct type. */
7883 {
7891 {
7894 }
7895 }
7897 /* If a pointer to a function that is multi-versioned is requested, the
7898 pointer to the dispatcher function is returned instead. This works
7899 well because indirectly calling the function will dispatch the right
7900 function version at run-time. */
7902 {
7906 /* Mark all the versions corresponding to the dispatcher as used. */
7909 }
7911 /* If we're doing overload resolution purely for the purpose of
7912 determining conversion sequences, we should not consider the
7913 function used. If this conversion sequence is selected, the
7914 function will be marked as used at this point. */
7916 {
7917 /* Make =delete work with SFINAE. */
7922 }
7924 /* We could not check access to member functions when this
7925 expression was originally created since we did not know at that
7926 time to which function the expression referred. */
7928 {
7931 }
7935 else
7936 {
7937 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
7938 will mark the function as addressed, but here we must do it
7939 explicitly. */
7943 }
7944 }
7946 /* This function will instantiate the type of the expression given in
7947 RHS to match the type of LHSTYPE. If errors exist, then return
7948 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
7949 we complain on errors. If we are not complaining, never modify rhs,
7950 as overload resolution wants to try many possible instantiations, in
7951 the hope that at least one will work.
7953 For non-recursive calls, LHSTYPE should be a function, pointer to
7954 function, or a pointer to member function. */
7956 tree
7958 {
7965 {
7969 }
7972 {
7981 /* Microsoft allows `A::f' to be resolved to a
7982 pointer-to-member. */
7983 ;
7984 else
7985 {
7990 }
7991 }
7994 {
7997 }
7999 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
8000 deduce any type information. */
8002 {
8006 }
8008 /* If we instantiate a template, and it is a A ?: C expression
8009 with omitted B, look through the SAVE_EXPR. */
8013 /* There are only a few kinds of expressions that may have a type
8014 dependent on overload resolution. */
8020 /* This should really only be used when attempting to distinguish
8021 what sort of a pointer to function we have. For now, any
8022 arithmetic operation which is not supported on pointers
8023 is rejected as an error. */
8026 {
8028 {
8034 /* Do not lose object's side effects. */
8038 }
8045 /* This can happen if we are forming a pointer-to-member for a
8046 member template. */
8049 /* Fall through. */
8052 {
8056 return
8060 }
8064 return
8068 access_path);
8071 {
8076 }
8083 }
8085 }
8086 \f
8087 /* Return the name of the virtual function pointer field
8088 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8089 this may have to look back through base types to find the
8090 ultimate field name. (For single inheritance, these could
8091 all be the same name. Who knows for multiple inheritance). */
8093 static tree
8095 {
8101 {
8107 }
8115 }
8117 void
8119 {
8126 {
8131 }
8132 }
8134 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8135 according to [class]:
8136 The class-name is also inserted
8137 into the scope of the class itself. For purposes of access checking,
8138 the inserted class name is treated as if it were a public member name. */
8140 void
8142 {
8159 }
8161 /* Returns 1 if TYPE contains only padding bytes. */
8163 int
8165 {
8173 }
8175 /* Returns true if TYPE contains no actual data, just various
8176 possible combinations of empty classes and possibly a vptr. */
8178 bool
8180 {
8182 {
8183 tree field;
8184 tree binfo;
8185 tree base_binfo;
8188 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8189 out, but we'd like to be able to check this before then. */
8200 /* An unnamed bit-field is not a data member. */
8205 }
8210 }
8212 /* Note that NAME was looked up while the current class was being
8213 defined and that the result of that lookup was DECL. */
8215 void
8217 {
8218 splay_tree names_used;
8220 /* If we're not defining a class, there's nothing to do. */
8226 /* If there's already a binding for this NAME, then we don't have
8227 anything to worry about. */
8240 }
8242 /* Note that NAME was declared (as DECL) in the current class. Check
8243 to see that the declaration is valid. */
8245 void
8247 {
8248 splay_tree names_used;
8249 splay_tree_node n;
8251 /* Look to see if we ever used this name. */
8252 names_used
8256 /* The C language allows members to be declared with a type of the same
8257 name, and the C++ standard says this diagnostic is not required. So
8258 allow it in extern "C" blocks unless predantic is specified.
8259 Allow it in all cases if -ms-extensions is specified. */
8265 {
8266 /* [basic.scope.class]
8268 A name N used in a class S shall refer to the same declaration
8269 in its context and when re-evaluated in the completed scope of
8270 S. */
8275 }
8276 }
8278 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8279 Secondary vtables are merged with primary vtables; this function
8280 will return the VAR_DECL for the primary vtable. */
8282 tree
8284 {
8285 tree decl;
8289 {
8292 }
8296 }
8299 /* Returns the binfo for the primary base of BINFO. If the resulting
8300 BINFO is a virtual base, and it is inherited elsewhere in the
8301 hierarchy, then the returned binfo might not be the primary base of
8302 BINFO in the complete object. Check BINFO_PRIMARY_P or
8303 BINFO_LOST_PRIMARY_P to be sure. */
8305 static tree
8307 {
8308 tree primary_base;
8315 }
8317 /* As above, but iterate until we reach the binfo that actually provides the
8318 vptr for BINFO. */
8320 static tree
8322 {
8326 {
8331 }
8333 }
8335 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8336 type. Note that the virtual inheritance might be above or below BINFO in
8337 the hierarchy. */
8339 bool
8341 {
8345 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8346 a morally virtual base. */
8349 }
8351 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8353 static int
8355 {
8359 }
8361 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8362 INDENT should be zero when called from the top level; it is
8363 incremented recursively. IGO indicates the next expected BINFO in
8364 inheritance graph ordering. */
8366 static tree
8368 dump_flags_t flags,
8369 tree binfo,
8370 tree igo,
8372 {
8374 tree base_binfo;
8382 {
8385 }
8400 {
8404 TFF_PLAIN_IDENTIFIER),
8406 }
8408 {
8411 }
8416 {
8420 {
8424 TFF_PLAIN_IDENTIFIER));
8425 }
8427 {
8431 TFF_PLAIN_IDENTIFIER));
8432 }
8434 {
8438 TFF_PLAIN_IDENTIFIER));
8439 }
8441 {
8445 TFF_PLAIN_IDENTIFIER));
8446 }
8450 }
8456 }
8458 /* Dump the BINFO hierarchy for T. */
8460 static void
8462 {
8474 }
8476 /* Debug interface to hierarchy dumping. */
8478 void
8480 {
8482 }
8484 static void
8486 {
8487 dump_flags_t flags;
8489 {
8492 }
8493 }
8495 static void
8497 {
8498 tree value;
8500 HOST_WIDE_INT elt;
8508 TFF_PLAIN_IDENTIFIER));
8515 }
8517 static void
8519 {
8520 dump_flags_t flags;
8527 {
8534 {
8539 }
8543 }
8546 }
8548 static void
8550 {
8551 dump_flags_t flags;
8558 {
8563 }
8566 }
8568 /* Dump a function or thunk and its thunkees. */
8570 static void
8572 {
8575 tree thunks;
8583 {
8593 else
8599 }
8603 }
8605 /* Dump the thunks for FN. */
8607 void
8609 {
8611 }
8613 /* Virtual function table initialization. */
8615 /* Create all the necessary vtables for T and its base classes. */
8617 static void
8619 {
8620 tree vbase;
8624 /* We lay out the primary and secondary vtables in one contiguous
8625 vtable. The primary vtable is first, followed by the non-virtual
8626 secondary vtables in inheritance graph order. */
8630 /* Then come the virtual bases, also in inheritance graph order. */
8632 {
8636 }
8640 }
8642 /* Initialize the vtable for BINFO with the INITS. */
8644 static void
8646 {
8647 tree decl;
8653 }
8655 /* Build the VTT (virtual table table) for T.
8656 A class requires a VTT if it has virtual bases.
8658 This holds
8659 1 - primary virtual pointer for complete object T
8660 2 - secondary VTTs for each direct non-virtual base of T which requires a
8661 VTT
8662 3 - secondary virtual pointers for each direct or indirect base of T which
8663 has virtual bases or is reachable via a virtual path from T.
8664 4 - secondary VTTs for each direct or indirect virtual base of T.
8666 Secondary VTTs look like complete object VTTs without part 4. */
8668 static void
8670 {
8671 tree type;
8672 tree vtt;
8673 tree index;
8676 /* Build up the initializers for the VTT. */
8681 /* If we didn't need a VTT, we're done. */
8685 /* Figure out the type of the VTT. */
8689 /* Now, build the VTT object itself. */
8692 /* Add the VTT to the vtables list. */
8697 }
8699 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8700 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8701 and CHAIN the vtable pointer for this binfo after construction is
8702 complete. VALUE can also be another BINFO, in which case we recurse. */
8704 static tree
8706 {
8707 tree vt;
8710 {
8716 else
8718 }
8721 }
8723 /* Data for secondary VTT initialization. */
8724 struct secondary_vptr_vtt_init_data
8725 {
8726 /* Is this the primary VTT? */
8729 /* Current index into the VTT. */
8730 tree index;
8732 /* Vector of initializers built up. */
8735 /* The type being constructed by this secondary VTT. */
8736 tree type_being_constructed;
8737 };
8739 /* Recursively build the VTT-initializer for BINFO (which is in the
8740 hierarchy dominated by T). INITS points to the end of the initializer
8741 list to date. INDEX is the VTT index where the next element will be
8742 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8743 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8744 for virtual bases of T. When it is not so, we build the constructor
8745 vtables for the BINFO-in-T variant. */
8747 static void
8750 {
8752 tree b;
8753 tree init;
8754 secondary_vptr_vtt_init_data data;
8757 /* We only need VTTs for subobjects with virtual bases. */
8761 /* We need to use a construction vtable if this is not the primary
8762 VTT. */
8764 {
8767 /* Record the offset in the VTT where this sub-VTT can be found. */
8769 }
8771 /* Add the address of the primary vtable for the complete object. */
8775 {
8778 }
8781 /* Recursively add the secondary VTTs for non-virtual bases. */
8786 /* Add secondary virtual pointers for all subobjects of BINFO with
8787 either virtual bases or reachable along a virtual path, except
8788 subobjects that are non-virtual primary bases. */
8798 /* data.inits might have grown as we added secondary virtual pointers.
8799 Make sure our caller knows about the new vector. */
8803 /* Add the secondary VTTs for virtual bases in inheritance graph
8804 order. */
8806 {
8811 }
8812 else
8813 /* Remove the ctor vtables we created. */
8815 }
8817 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8818 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8820 static tree
8822 {
8825 /* We don't care about bases that don't have vtables. */
8829 /* We're only interested in proper subobjects of the type being
8830 constructed. */
8834 /* We're only interested in bases with virtual bases or reachable
8835 via a virtual path from the type being constructed. */
8840 /* We're not interested in non-virtual primary bases. */
8844 /* Record the index where this secondary vptr can be found. */
8846 {
8851 {
8852 /* It's a primary virtual base, and this is not a
8853 construction vtable. Find the base this is primary of in
8854 the inheritance graph, and use that base's vtable
8855 now. */
8858 }
8859 }
8861 /* Add the initializer for the secondary vptr itself. */
8864 /* Advance the vtt index. */
8869 }
8871 /* Called from build_vtt_inits via dfs_walk. After building
8872 constructor vtables and generating the sub-vtt from them, we need
8873 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8874 binfo of the base whose sub vtt was generated. */
8876 static tree
8878 {
8882 /* If this class has no vtable, none of its bases do. */
8886 /* This might be a primary base, so have no vtable in this
8887 hierarchy. */
8890 /* If we scribbled the construction vtable vptr into BINFO, clear it
8891 out now. */
8897 }
8899 /* Build the construction vtable group for BINFO which is in the
8900 hierarchy dominated by T. */
8902 static void
8904 {
8905 tree type;
8906 tree vtbl;
8907 tree id;
8908 tree vbase;
8911 /* See if we've already created this construction vtable group. */
8917 /* Build a version of VTBL (with the wrong type) for use in
8918 constructing the addresses of secondary vtables in the
8919 construction vtable group. */
8922 /* Don't export construction vtables from shared libraries. Even on
8923 targets that don't support hidden visibility, this tells
8924 can_refer_decl_in_current_unit_p not to assume that it's safe to
8925 access from a different compilation unit (bz 54314). */
8933 /* Add the vtables for each of our virtual bases using the vbase in T
8934 binfo. */
8936 vbase;
8938 {
8939 tree b;
8946 }
8948 /* Figure out the type of the construction vtable. */
8955 /* Initialize the construction vtable. */
8959 }
8961 /* Add the vtbl initializers for BINFO (and its bases other than
8962 non-virtual primaries) to the list of INITS. BINFO is in the
8963 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
8964 the constructor the vtbl inits should be accumulated for. (If this
8965 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
8966 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
8967 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
8968 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
8969 but are not necessarily the same in terms of layout. */
8971 static void
8973 tree orig_binfo,
8974 tree rtti_binfo,
8975 tree vtbl,
8976 tree t,
8978 {
8980 tree base_binfo;
8985 /* If it doesn't have a vptr, we don't do anything. */
8989 /* If we're building a construction vtable, we're not interested in
8990 subobjects that don't require construction vtables. */
8996 /* Build the initializers for the BINFO-in-T vtable. */
8999 /* Walk the BINFO and its bases. We walk in preorder so that as we
9000 initialize each vtable we can figure out at what offset the
9001 secondary vtable lies from the primary vtable. We can't use
9002 dfs_walk here because we need to iterate through bases of BINFO
9003 and RTTI_BINFO simultaneously. */
9005 {
9006 /* Skip virtual bases. */
9012 inits);
9013 }
9014 }
9016 /* Called from accumulate_vtbl_inits. Adds the initializers for the
9017 BINFO vtable to L. */
9019 static void
9021 tree orig_binfo,
9022 tree rtti_binfo,
9023 tree orig_vtbl,
9024 tree t,
9026 {
9033 {
9034 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9035 primary virtual base. If it is not the same primary in
9036 the hierarchy of T, we'll need to generate a ctor vtable
9037 for it, to place at its location in T. If it is the same
9038 primary, we still need a VTT entry for the vtable, but it
9039 should point to the ctor vtable for the base it is a
9040 primary for within the sub-hierarchy of RTTI_BINFO.
9042 There are three possible cases:
9044 1) We are in the same place.
9045 2) We are a primary base within a lost primary virtual base of
9046 RTTI_BINFO.
9047 3) We are primary to something not a base of RTTI_BINFO. */
9049 tree b;
9052 /* First, look through the bases we are primary to for RTTI_BINFO
9053 or a virtual base. */
9056 {
9061 }
9062 /* If we run out of primary links, keep looking down our
9063 inheritance chain; we might be an indirect primary. */
9067 found:
9069 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9070 base B and it is a base of RTTI_BINFO, this is case 2. In
9071 either case, we share our vtable with LAST, i.e. the
9072 derived-most base within B of which we are a primary. */
9075 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9076 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9077 binfo_ctor_vtable after everything's been set up. */
9080 /* Otherwise, this is case 3 and we get our own. */
9081 }
9088 {
9089 tree index;
9092 /* Add the initializer for this vtable. */
9096 /* Figure out the position to which the VPTR should point. */
9102 }
9105 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9106 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9107 straighten this out. */
9110 /* Throw away any unneeded intializers. */
9112 else
9113 /* For an ordinary vtable, set BINFO_VTABLE. */
9115 }
9120 /* Construct the initializer for BINFO's virtual function table. BINFO
9121 is part of the hierarchy dominated by T. If we're building a
9122 construction vtable, the ORIG_BINFO is the binfo we should use to
9123 find the actual function pointers to put in the vtable - but they
9124 can be overridden on the path to most-derived in the graph that
9125 ORIG_BINFO belongs. Otherwise,
9126 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9127 BINFO that should be indicated by the RTTI information in the
9128 vtable; it will be a base class of T, rather than T itself, if we
9129 are building a construction vtable.
9131 The value returned is a TREE_LIST suitable for wrapping in a
9132 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9133 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9134 number of non-function entries in the vtable.
9136 It might seem that this function should never be called with a
9137 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9138 base is always subsumed by a derived class vtable. However, when
9139 we are building construction vtables, we do build vtables for
9140 primary bases; we need these while the primary base is being
9141 constructed. */
9143 static void
9145 tree orig_binfo,
9146 tree t,
9147 tree rtti_binfo,
9150 {
9151 tree v;
9152 vtbl_init_data vid;
9154 tree vbinfo;
9158 /* Initialize VID. */
9166 /* The first vbase or vcall offset is at index -3 in the vtable. */
9169 /* Add entries to the vtable for RTTI. */
9172 /* Create an array for keeping track of the functions we've
9173 processed. When we see multiple functions with the same
9174 signature, we share the vcall offsets. */
9176 /* Add the vcall and vbase offset entries. */
9179 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9180 build_vbase_offset_vtbl_entries. */
9185 /* If the target requires padding between data entries, add that now. */
9187 {
9192 /* Move data entries into their new positions and add padding
9193 after the new positions. Iterate backwards so we don't
9194 overwrite entries that we would need to process later. */
9197 ix--)
9198 {
9206 {
9210 null_pointer_node);
9211 }
9212 }
9213 }
9218 /* The initializers for virtual functions were built up in reverse
9219 order. Straighten them out and add them to the running list in one
9220 step. */
9229 /* Go through all the ordinary virtual functions, building up
9230 initializers. */
9232 {
9233 tree delta;
9234 tree vcall_index;
9241 {
9245 {
9248 }
9250 }
9252 /* If the only definition of this function signature along our
9253 primary base chain is from a lost primary, this vtable slot will
9254 never be used, so just zero it out. This is important to avoid
9255 requiring extra thunks which cannot be generated with the function.
9257 We first check this in update_vtable_entry_for_fn, so we handle
9258 restored primary bases properly; we also need to do it here so we
9259 zero out unused slots in ctor vtables, rather than filling them
9260 with erroneous values (though harmless, apart from relocation
9261 costs). */
9266 {
9267 /* Pull the offset for `this', and the function to call, out of
9268 the list. */
9275 /* You can't call an abstract virtual function; it's abstract.
9276 So, we replace these functions with __pure_virtual. */
9278 {
9281 {
9283 abort_fndecl_addr
9287 }
9288 }
9289 /* Likewise for deleted virtuals. */
9291 {
9293 {
9297 dvirt_fn = push_library_fn
9301 }
9306 }
9307 else
9308 {
9310 {
9315 }
9316 /* Take the address of the function, considering it to be of an
9317 appropriate generic type. */
9321 /* Don't refer to a virtual destructor from a constructor
9322 vtable or a vtable for an abstract class, since destroying
9323 an object under construction is undefined behavior and we
9324 don't want it to be considered a candidate for speculative
9325 devirtualization. But do create the thunk for ABI
9326 compliance. */
9331 }
9332 }
9334 /* And add it to the chain of initializers. */
9336 {
9341 else
9343 {
9349 }
9350 }
9351 else
9353 }
9354 }
9356 /* Adds to vid->inits the initializers for the vbase and vcall
9357 offsets in BINFO, which is in the hierarchy dominated by T. */
9359 static void
9361 {
9362 tree b;
9364 /* If this is a derived class, we must first create entries
9365 corresponding to the primary base class. */
9370 /* Add the vbase entries for this base. */
9372 /* Add the vcall entries for this base. */
9374 }
9376 /* Returns the initializers for the vbase offset entries in the vtable
9377 for BINFO (which is part of the class hierarchy dominated by T), in
9378 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9379 where the next vbase offset will go. */
9381 static void
9383 {
9384 tree vbase;
9385 tree t;
9386 tree non_primary_binfo;
9388 /* If there are no virtual baseclasses, then there is nothing to
9389 do. */
9395 /* We might be a primary base class. Go up the inheritance hierarchy
9396 until we find the most derived class of which we are a primary base:
9397 it is the offset of that which we need to use. */
9400 {
9401 tree b;
9403 /* If we have reached a virtual base, then it must be a primary
9404 base (possibly multi-level) of vid->binfo, or we wouldn't
9405 have called build_vcall_and_vbase_vtbl_entries for it. But it
9406 might be a lost primary, so just skip down to vid->binfo. */
9408 {
9411 }
9417 }
9419 /* Go through the virtual bases, adding the offsets. */
9421 vbase;
9423 {
9424 tree b;
9425 tree delta;
9430 /* Find the instance of this virtual base in the complete
9431 object. */
9434 /* If we've already got an offset for this virtual base, we
9435 don't need another one. */
9440 /* Figure out where we can find this vbase offset. */
9449 /* The vbase offset had better be the same. */
9452 /* The next vbase will come at a more negative offset. */
9456 /* The initializer is the delta from BINFO to this virtual base.
9457 The vbase offsets go in reverse inheritance-graph order, and
9458 we are walking in inheritance graph order so these end up in
9459 the right order. */
9466 }
9467 }
9469 /* Adds the initializers for the vcall offset entries in the vtable
9470 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9471 to VID->INITS. */
9473 static void
9475 {
9476 /* We only need these entries if this base is a virtual base. We
9477 compute the indices -- but do not add to the vtable -- when
9478 building the main vtable for a class. */
9481 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9482 correspond to VID->DERIVED), we are building a primary
9483 construction virtual table. Since this is a primary
9484 virtual table, we do not need the vcall offsets for
9485 BINFO. */
9487 {
9488 /* We need a vcall offset for each of the virtual functions in this
9489 vtable. For example:
9491 class A { virtual void f (); };
9492 class B1 : virtual public A { virtual void f (); };
9493 class B2 : virtual public A { virtual void f (); };
9494 class C: public B1, public B2 { virtual void f (); };
9496 A C object has a primary base of B1, which has a primary base of A. A
9497 C also has a secondary base of B2, which no longer has a primary base
9498 of A. So the B2-in-C construction vtable needs a secondary vtable for
9499 A, which will adjust the A* to a B2* to call f. We have no way of
9500 knowing what (or even whether) this offset will be when we define B2,
9501 so we store this "vcall offset" in the A sub-vtable and look it up in
9502 a "virtual thunk" for B2::f.
9504 We need entries for all the functions in our primary vtable and
9505 in our non-virtual bases' secondary vtables. */
9507 /* If we are just computing the vcall indices -- but do not need
9508 the actual entries -- not that. */
9511 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9513 }
9514 }
9516 /* Build vcall offsets, starting with those for BINFO. */
9518 static void
9520 {
9522 tree primary_binfo;
9523 tree base_binfo;
9525 /* Don't walk into virtual bases -- except, of course, for the
9526 virtual base for which we are building vcall offsets. Any
9527 primary virtual base will have already had its offsets generated
9528 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9532 /* If BINFO has a primary base, process it first. */
9537 /* Add BINFO itself to the list. */
9540 /* Scan the non-primary bases of BINFO. */
9544 }
9546 /* Called from build_vcall_offset_vtbl_entries_r. */
9548 static void
9550 {
9551 /* Make entries for the rest of the virtuals. */
9552 tree orig_fn;
9554 /* The ABI requires that the methods be processed in declaration
9555 order. */
9557 orig_fn;
9561 }
9563 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9565 static void
9567 {
9569 tree vcall_offset;
9570 tree derived_entry;
9572 /* If there is already an entry for a function with the same
9573 signature as FN, then we do not need a second vcall offset.
9574 Check the list of functions already present in the derived
9575 class vtable. */
9577 {
9579 /* We only use one vcall offset for virtual destructors,
9580 even though there are two virtual table entries. */
9584 }
9586 /* If we are building these vcall offsets as part of building
9587 the vtable for the most derived class, remember the vcall
9588 offset. */
9590 {
9593 }
9595 /* The next vcall offset will be found at a more negative
9596 offset. */
9600 /* Keep track of this function. */
9604 {
9605 tree base;
9606 tree fn;
9608 /* Find the overriding function. */
9612 else
9613 {
9616 /* The vbase we're working on is a primary base of
9617 vid->binfo. But it might be a lost primary, so its
9618 BINFO_OFFSET might be wrong, so we just use the
9619 BINFO_OFFSET from vid->binfo. */
9625 vcall_offset);
9626 }
9627 /* Add the initializer to the vtable. */
9629 }
9630 }
9632 /* Return vtbl initializers for the RTTI entries corresponding to the
9633 BINFO's vtable. The RTTI entries should indicate the object given
9634 by VID->rtti_binfo. */
9636 static void
9638 {
9639 tree b;
9640 tree t;
9641 tree offset;
9642 tree decl;
9643 tree init;
9647 /* To find the complete object, we will first convert to our most
9648 primary base, and then add the offset in the vtbl to that value. */
9653 /* The second entry is the address of the typeinfo object. */
9656 else
9659 /* Convert the declaration to a type that can be stored in the
9660 vtable. */
9664 /* Add the offset-to-top entry. It comes earlier in the vtable than
9665 the typeinfo entry. Convert the offset to look like a
9666 function pointer, so that we can put it in the vtable. */
9669 }
9671 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9672 accessibility. */
9674 bool
9676 {
9679 }
9681 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9683 bool
9685 {
9689 }
9691 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9692 class between them, if any. */
9694 tree
9696 {
9708 {
9711 }
9715 }