| blob | e48a04ade7de9f32ddead55e83b8e1f992929f00 |
1 /* Functions related to building classes and their related objects.
2 Copyright (C) 1987-2018 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
22 /* High-level class interface. */
41 /* Id for dumping the class hierarchy. */
44 /* The number of nested classes being processed. If we are not in the
45 scope of any class, this is zero. */
49 /* In order to deal with nested classes, we keep a stack of classes.
50 The topmost entry is the innermost class, and is the entry at index
51 CURRENT_CLASS_DEPTH */
54 /* The name of the class. */
55 tree name;
57 /* The _TYPE node for the class. */
58 tree type;
60 /* The access specifier pending for new declarations in the scope of
61 this class. */
62 tree access;
64 /* If were defining TYPE, the names used in this class. */
65 splay_tree names_used;
67 /* Nonzero if this class is no longer open, because of a call to
68 push_to_top_level. */
72 struct vtbl_init_data
73 {
74 /* The base for which we're building initializers. */
75 tree binfo;
76 /* The type of the most-derived type. */
77 tree derived;
78 /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
79 unless ctor_vtbl_p is true. */
80 tree rtti_binfo;
81 /* The negative-index vtable initializers built up so far. These
82 are in order from least negative index to most negative index. */
84 /* The binfo for the virtual base for which we're building
85 vcall offset initializers. */
86 tree vbase;
87 /* The functions in vbase for which we have already provided vcall
88 offsets. */
90 /* The vtable index of the next vcall or vbase offset. */
91 tree index;
92 /* Nonzero if we are building the initializer for the primary
93 vtable. */
95 /* Nonzero if we are building the initializer for a construction
96 vtable. */
98 /* True when adding vcall offset entries to the vtable. False when
99 merely computing the indices. */
101 };
103 /* The type of a function passed to walk_subobject_offsets. */
106 /* The stack itself. This is a dynamically resized array. The
107 number of elements allocated is CURRENT_CLASS_STACK_SIZE. */
111 /* The size of the largest empty class seen in this translation unit. */
114 /* An array of all local classes present in this translation unit, in
115 declaration order. */
148 /* Used by find_flexarrays and related functions. */
199 tree *);
209 splay_tree_key k2);
218 /* Return a COND_EXPR that executes TRUE_STMT if this execution of the
219 'structor is in charge of 'structing virtual bases, or FALSE_STMT
220 otherwise. */
222 tree
224 {
234 }
236 /* Convert to or from a base subobject. EXPR is an expression of type
237 `A' or `A*', an expression of type `B' or `B*' is returned. To
238 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
239 the B base instance within A. To convert base A to derived B, CODE
240 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
241 In this latter case, A must not be a morally virtual base of B.
242 NONNULL is true if EXPR is known to be non-NULL (this is only
243 needed when EXPR is of pointer type). CV qualifiers are preserved
244 from EXPR. */
246 tree
248 tree expr,
249 tree binfo,
251 tsubst_flags_t complain)
252 {
255 tree probe;
256 tree offset;
257 tree target_type;
259 tree ptr_target_type;
270 {
276 }
284 {
285 /* This can happen when adjust_result_of_qualified_name_lookup can't
286 find a unique base binfo in a call to a member function. We
287 couldn't give the diagnostic then since we might have been calling
288 a static member function, so we do it now. In other cases, eg.
289 during error recovery (c++/71979), we may not have a base at all. */
291 {
295 }
297 }
304 /* Nothing to do. */
308 {
310 {
312 {
315 "pointer to derived class %qT because the base is "
317 else
321 }
322 else
323 {
329 else
333 }
334 }
336 }
339 {
341 /* This must happen before the call to save_expr. */
343 }
344 else
350 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
351 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
352 expression returned matches the input. */
353 target_type = cp_build_qualified_type
357 /* Do we need to look in the vtable for the real offset? */
360 /* Don't bother with the calculations inside sizeof; they'll ICE if the
361 source type is incomplete and the pointer value doesn't matter. In a
362 template (even in instantiate_non_dependent_expr), we don't have vtables
363 set up properly yet, and the value doesn't matter there either; we're
364 just interested in the result of overload resolution. */
366 || processing_template_decl
368 {
371 }
373 /* If we're in an NSDMI, we don't have the full constructor context yet
374 that we need for converting to a virtual base, so just build a stub
375 CONVERT_EXPR and expand it later in bot_replace. */
378 {
382 }
384 /* Do we need to check for a null pointer? */
386 {
387 /* If we know the conversion will not actually change the value
388 of EXPR, then we can avoid testing the expression for NULL.
389 We have to avoid generating a COMPONENT_REF for a base class
390 field, because other parts of the compiler know that such
391 expressions are always non-NULL. */
395 }
397 /* Protect against multiple evaluation if necessary. */
401 /* Now that we've saved expr, build the real null test. */
403 {
407 /* This is a compiler generated comparison, don't emit
408 e.g. -Wnonnull-compare warning for it. */
410 }
412 /* If this is a simple base reference, express it as a COMPONENT_REF. */
414 /* We don't build base fields for empty bases, and they aren't very
415 interesting to the optimizers anyway. */
417 {
426 }
429 {
430 /* Going via virtual base V_BINFO. We need the static offset
431 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
432 V_BINFO. That offset is an entry in D_BINFO's vtable. */
433 tree v_offset;
436 {
437 /* In a base member initializer, we cannot rely on the
438 vtable being set up. We have to indirect via the
439 vtt_parm. */
440 tree t;
446 }
447 else
448 {
452 {
457 }
460 }
468 v_offset);
480 /* Negative fixed_type_p means this is a constructor or destructor;
481 virtual base layout is fixed in in-charge [cd]tors, but not in
482 base [cd]tors. */
483 offset = build_if_in_charge
485 v_offset);
486 else
488 }
496 {
501 }
502 else
505 indout:
507 {
511 }
513 out:
519 }
521 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
522 Perform a derived-to-base conversion by recursively building up a
523 sequence of COMPONENT_REFs to the appropriate base fields. */
525 static tree
527 {
530 tree field;
533 {
534 tree temp;
538 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
539 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
540 an lvalue in the front end; only _DECLs and _REFs are lvalues
541 in the back end. */
547 }
549 /* Recurse. */
554 /* Is this the base field created by build_base_field? */
558 /* If we're looking for a field in the most-derived class,
559 also check the field offset; we can have two base fields
560 of the same type if one is an indirect virtual base and one
561 is a direct non-virtual base. */
565 {
566 /* We don't use build_class_member_access_expr here, as that
567 has unnecessary checks, and more importantly results in
568 recursive calls to dfs_walk_once. */
574 /* Mark the expression const or volatile, as appropriate.
575 Even though we've dealt with the type above, we still have
576 to mark the expression itself. */
583 }
585 /* Didn't find the base field?!? */
587 }
589 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
590 type is a class type or a pointer to a class type. In the former
591 case, TYPE is also a class type; in the latter it is another
592 pointer type. If CHECK_ACCESS is true, an error message is emitted
593 if TYPE is inaccessible. If OBJECT has pointer type, the value is
594 assumed to be non-NULL. */
596 tree
598 tsubst_flags_t complain)
599 {
600 tree binfo;
601 tree object_type;
604 {
607 }
608 else
617 }
619 /* EXPR is an expression with unqualified class type. BASE is a base
620 binfo of that class type. Returns EXPR, converted to the BASE
621 type. This function assumes that EXPR is the most derived class;
622 therefore virtual bases can be found at their static offsets. */
624 tree
626 {
627 tree expr_type;
631 {
632 /* If this is a non-empty base, use a COMPONENT_REF. */
636 /* We use fold_build2 and fold_convert below to simplify the trees
637 provided to the optimizers. It is not safe to call these functions
638 when processing a template because they do not handle C++-specific
639 trees. */
647 }
650 }
652 \f
653 tree
655 {
659 /* Can happen in case of duplicate base types (c++/59082). */
663 /* First, convert to the requested type. */
668 /* Second, the requested type may not be the owner of its own vptr.
669 If not, convert to the base class that owns it. We cannot use
670 convert_to_base here, because VCONTEXT may appear more than once
671 in the inheritance hierarchy of TYPE, and thus direct conversion
672 between the types may be ambiguous. Following the path back up
673 one step at a time via primary bases avoids the problem. */
677 {
680 }
683 }
685 /* Given an object INSTANCE, return an expression which yields the
686 vtable element corresponding to INDEX. There are many special
687 cases for INSTANCE which we take care of here, mainly to avoid
688 creating extra tree nodes when we don't have to. */
690 static tree
692 {
693 tree aref;
696 /* Try to figure out what a reference refers to, and
697 access its virtual function table directly. */
705 {
710 }
719 }
721 tree
723 {
727 }
729 /* Given a stable object pointer INSTANCE_PTR, return an expression which
730 yields a function pointer corresponding to vtable element INDEX. */
732 tree
734 {
735 tree aref;
738 idx);
740 /* When using function descriptors, the address of the
741 vtable entry is treated as a function pointer. */
746 /* Remember this as a method reference, for later devirtualization. */
750 }
752 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
753 for the given TYPE. */
755 static tree
757 {
759 }
761 /* DECL is an entity associated with TYPE, like a virtual table or an
762 implicitly generated constructor. Determine whether or not DECL
763 should have external or internal linkage at the object file
764 level. This routine does not deal with COMDAT linkage and other
765 similar complexities; it simply sets TREE_PUBLIC if it possible for
766 entities in other translation units to contain copies of DECL, in
767 the abstract. */
769 void
771 {
774 }
776 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
777 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
778 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
780 static tree
782 {
783 tree decl;
786 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
787 now to avoid confusion in mangle_decl. */
798 /* The vtable has not been defined -- yet. */
802 /* Mark the VAR_DECL node representing the vtable itself as a
803 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
804 is rather important that such things be ignored because any
805 effort to actually generate DWARF for them will run into
806 trouble when/if we encounter code like:
808 #pragma interface
809 struct S { virtual void member (); };
811 because the artificial declaration of the vtable itself (as
812 manufactured by the g++ front end) will say that the vtable is
813 a static member of `S' but only *after* the debug output for
814 the definition of `S' has already been output. This causes
815 grief because the DWARF entry for the definition of the vtable
816 will try to refer back to an earlier *declaration* of the
817 vtable as a static member of `S' and there won't be one. We
818 might be able to arrange to have the "vtable static member"
819 attached to the member list for `S' before the debug info for
820 `S' get written (which would solve the problem) but that would
821 require more intrusive changes to the g++ front end. */
825 }
827 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
828 or even complete. If this does not exist, create it. If COMPLETE is
829 nonzero, then complete the definition of it -- that will render it
830 impossible to actually build the vtable, but is useful to get at those
831 which are known to exist in the runtime. */
833 tree
835 {
836 tree decl;
845 {
848 }
851 }
853 /* Build the primary virtual function table for TYPE. If BINFO is
854 non-NULL, build the vtable starting with the initial approximation
855 that it is the same as the one which is the head of the association
856 list. Returns a nonzero value if a new vtable is actually
857 created. */
859 static int
861 {
862 tree decl;
863 tree virtuals;
868 {
870 /* We have already created a vtable for this base, so there's
871 no need to do it again. */
878 }
879 else
880 {
883 }
885 /* Initialize the association list for this type, based
886 on our first approximation. */
891 }
893 /* Give BINFO a new virtual function table which is initialized
894 with a skeleton-copy of its original initialization. The only
895 entry that changes is the `delta' entry, so we can really
896 share a lot of structure.
898 FOR_TYPE is the most derived type which caused this table to
899 be needed.
901 Returns nonzero if we haven't met BINFO before.
903 The order in which vtables are built (by calling this function) for
904 an object must remain the same, otherwise a binary incompatibility
905 can result. */
907 static int
909 {
911 /* We already created a vtable for this base. There's no need to
912 do it again. */
915 /* Remember that we've created a vtable for this BINFO, so that we
916 don't try to do so again. */
919 /* Make fresh virtual list, so we can smash it later. */
922 /* Secondary vtables are laid out as part of the same structure as
923 the primary vtable. */
926 }
928 /* Create a new vtable for BINFO which is the hierarchy dominated by
929 T. Return nonzero if we actually created a new vtable. */
931 static int
933 {
935 /* In this case, it is *type*'s vtable we are modifying. We start
936 with the approximation that its vtable is that of the
937 immediate base class. */
939 else
940 /* This is our very own copy of `basetype' to play with. Later,
941 we will fill in all the virtual functions that override the
942 virtual functions in these base classes which are not defined
943 by the current type. */
945 }
947 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
948 (which is in the hierarchy dominated by T) list FNDECL as its
949 BV_FN. DELTA is the required constant adjustment from the `this'
950 pointer where the vtable entry appears to the `this' required when
951 the function is actually called. */
953 static void
955 tree binfo,
956 tree fndecl,
957 tree delta,
959 {
960 tree v;
966 {
967 /* We need a new vtable for BINFO. */
969 {
970 /* If we really did make a new vtable, we also made a copy
971 of the BINFO_VIRTUALS list. Now, we have to find the
972 corresponding entry in that list. */
977 }
982 }
983 }
985 \f
986 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
987 METHOD is being injected via a using_decl. Returns true if the
988 method could be added to the method vec. */
990 bool
992 {
996 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1004 /* Check to see if we've already got this method. */
1006 {
1008 tree fn_type;
1009 tree method_type;
1010 tree parms1;
1011 tree parms2;
1016 /* Two using-declarations can coexist, we'll complain about ambiguity in
1017 overload resolution. */
1019 /* Except handle inherited constructors specially. */
1023 /* [over.load] Member function declarations with the
1024 same name and the same parameter types cannot be
1025 overloaded if any of them is a static member
1026 function declaration.
1028 [over.load] Member function declarations with the same name and
1029 the same parameter-type-list as well as member function template
1030 declarations with the same name, the same parameter-type-list, and
1031 the same template parameter lists cannot be overloaded if any of
1032 them, but not all, have a ref-qualifier.
1034 [namespace.udecl] When a using-declaration brings names
1035 from a base class into a derived class scope, member
1036 functions in the derived class override and/or hide member
1037 functions with the same name and parameter types in a base
1038 class (rather than conflicting). */
1044 /* Compare the quals on the 'this' parm. Don't compare
1045 the whole types, as used functions are treated as
1046 coming from the using class in overload resolution. */
1049 /* Either both or neither need to be ref-qualified for
1050 differing quals to allow overloading. */
1057 /* For templates, the return type and template parameters
1058 must be identical. */
1071 /* Bring back parameters omitted from an inherited ctor. */
1082 {
1083 /* If these are versions of the same function, process and
1084 move on. */
1090 {
1092 {
1096 {
1098 {
1099 /* Inheriting the same constructor along different
1100 paths, combine them. */
1101 SET_DECL_INHERITED_CTOR
1104 /* And discard the new one. */
1106 }
1107 else
1108 /* Inherited ctors can coexist until overload
1109 resolution. */
1111 }
1117 basef);
1118 }
1119 /* Otherwise defer to the other function. */
1121 }
1124 /* Defer to the local function. */
1128 {
1129 /* Remove the inherited constructor. */
1132 }
1133 else
1134 {
1140 }
1141 }
1142 }
1144 /* A class should never have more than one destructor. */
1155 }
1157 /* Subroutines of finish_struct. */
1159 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1160 legit, otherwise return 0. */
1162 static int
1164 {
1165 tree elem;
1173 {
1175 {
1179 else
1182 }
1183 else
1184 {
1185 /* They're changing the access to the same thing they changed
1186 it to before. That's OK. */
1187 ;
1188 }
1189 }
1190 else
1191 {
1193 tf_warning_or_error);
1196 }
1198 }
1200 /* Return the access node for DECL's access in its enclosing class. */
1202 tree
1204 {
1208 }
1210 /* Process the USING_DECL, which is a member of T. */
1212 static void
1214 {
1219 tree old_value;
1224 tf_warning_or_error);
1226 {
1231 else
1233 }
1241 ;
1243 {
1245 /* It's OK to use functions from a base when there are functions with
1247 else
1248 {
1255 }
1256 }
1258 {
1265 }
1267 /* Make type T see field decl FDECL with access ACCESS. */
1270 {
1273 }
1274 else
1276 }
1277 \f
1278 /* Data structure for find_abi_tags_r, below. */
1280 struct abi_tag_data
1281 {
1285 };
1287 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1288 in the context of P. TAG can be either an identifier (the DECL_NAME of
1289 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1291 static void
1293 {
1295 {
1297 {
1298 /* We're collecting tags from template arguments or from
1299 the type of a variable or function return type. */
1302 /* Don't inherit this tag multiple times. */
1306 {
1307 /* Tags inherited from type template arguments are only used
1308 to avoid warnings. */
1311 }
1312 /* For functions and variables we want to warn, too. */
1313 }
1315 /* Otherwise we're diagnosing missing tags. */
1317 {
1322 }
1324 {
1328 }
1330 {
1335 }
1336 else
1337 {
1341 {
1345 }
1346 }
1347 }
1348 }
1350 /* Find all the ABI tags in the attribute list ATTR and either call
1351 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1353 static void
1355 {
1362 {
1367 else
1369 }
1370 }
1372 /* Find all the ABI tags on T and its enclosing scopes and either call
1373 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1375 static void
1377 {
1379 {
1380 tree attr;
1382 {
1385 }
1386 else
1387 {
1390 }
1392 }
1393 }
1395 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1396 types with ABI tags, add the corresponding identifiers to the VEC in
1397 *DATA and set IDENTIFIER_MARKED. */
1399 static tree
1401 {
1405 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1406 anyway, but let's make sure of it. */
1414 }
1416 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1417 IDENTIFIER_MARKED on its ABI tags. */
1419 static tree
1421 {
1425 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1426 anyway, but let's make sure of it. */
1434 }
1436 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1437 scopes. */
1439 static void
1441 {
1444 {
1447 {
1448 /* Template arguments are part of the signature. */
1451 {
1454 }
1455 }
1457 /* A function's parameter types are part of the signature, so
1458 we don't need to inherit any tags that are also in them. */
1463 }
1464 }
1466 /* Check that T has all the ABI tags that subobject SUBOB has, or
1467 warn if not. If T is a (variable or function) declaration, also
1468 return any missing tags, and add them to T if JUST_CHECKING is false. */
1470 static tree
1472 {
1480 /* No need to worry about things local to this TU. */
1496 {
1499 }
1500 else
1501 {
1505 else
1509 }
1514 }
1516 /* Check that DECL has all the ABI tags that are used in parts of its type
1517 that are not reflected in its mangled name. */
1519 void
1521 {
1528 }
1530 /* Return any ABI tags that are used in parts of the type of DECL
1531 that are not reflected in its mangled name. This function is only
1532 used in backward-compatible mangling for ABI <11. */
1534 tree
1536 {
1540 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1541 that we can use this function for setting need_abi_warning
1542 regardless of the current flag_abi_version. */
1545 else
1547 }
1549 void
1551 {
1561 {
1564 {
1568 }
1569 }
1571 // If we found some tags on our template arguments, add them to our
1572 // abi_tag attribute.
1574 {
1578 else
1582 }
1585 }
1587 /* Return true, iff class T has a non-virtual destructor that is
1588 accessible from outside the class heirarchy (i.e. is public, or
1589 there's a suitable friend. */
1591 static bool
1593 {
1596 /* An implicitly declared destructor is always public. And,
1597 if it were virtual, we would have created it by now. */
1612 }
1614 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1615 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1616 properties of the bases. */
1618 static void
1622 {
1626 tree base_binfo;
1627 tree binfo;
1637 {
1646 /* If any base class is non-literal, so is the derived class. */
1650 /* If the base class doesn't have copy constructors or
1651 assignment operators that take const references, then the
1652 derived class cannot have such a member automatically
1653 generated. */
1662 /* A virtual base does not effect nearly emptiness. */
1663 ;
1665 {
1667 /* And if there is more than one nearly empty base, then the
1668 derived class is not nearly empty either. */
1670 else
1671 /* Remember we've seen one. */
1673 }
1675 /* If the base class is not empty or nearly empty, then this
1676 class cannot be nearly empty. */
1679 /* A lot of properties from the bases also apply to the derived
1680 class. */
1697 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1700 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1706 /* A standard-layout class is a class that:
1707 ...
1708 * has no non-standard-layout base classes, */
1711 {
1712 tree basefield;
1713 /* ...has no base classes of the same type as the first non-static
1714 data member... */
1716 && (same_type_ignoring_top_level_qualifiers_p
1719 else
1720 /* ...either has no non-static data members in the most-derived
1721 class and at most one base class with non-static data
1722 members, or has no base classes with non-static data
1723 members */
1729 {
1732 else
1735 }
1736 }
1738 /* Don't bother collecting tm attributes if transactional memory
1739 support is not enabled. */
1741 {
1745 }
1748 }
1750 /* If one of the base classes had TM attributes, and the current class
1751 doesn't define its own, then the current class inherits one. */
1753 {
1756 }
1757 }
1759 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1760 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1761 that have had a nearly-empty virtual primary base stolen by some
1762 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1763 T. */
1765 static void
1767 {
1771 tree base_binfo;
1773 /* Determine the primary bases of our bases. */
1776 {
1779 /* See if we're the non-virtual primary of our inheritance
1780 chain. */
1782 {
1789 /* We are the primary binfo. */
1791 }
1792 /* Determine if we have a virtual primary base, and mark it so.
1793 */
1795 {
1799 /* Someone already claimed this base. */
1801 else
1802 {
1803 tree delta;
1808 /* A virtual binfo might have been copied from within
1809 another hierarchy. As we're about to use it as a
1810 primary base, make sure the offsets match. */
1818 }
1819 }
1820 }
1822 /* First look for a dynamic direct non-virtual base. */
1824 {
1828 {
1831 }
1832 }
1834 /* A "nearly-empty" virtual base class can be the primary base
1835 class, if no non-virtual polymorphic base can be found. Look for
1836 a nearly-empty virtual dynamic base that is not already a primary
1837 base of something in the hierarchy. If there is no such base,
1838 just pick the first nearly-empty virtual base. */
1844 {
1846 {
1847 /* Found one that is not primary. */
1850 }
1852 /* Remember the first candidate. */
1854 }
1856 found:
1857 /* If we've got a primary base, use it. */
1859 {
1864 /* We are stealing a primary base. */
1868 {
1869 tree delta;
1872 /* A virtual binfo might have been copied from within
1873 another hierarchy. As we're about to use it as a primary
1874 base, make sure the offsets match. */
1879 }
1886 }
1887 }
1889 /* Update the variant types of T. */
1891 void
1893 {
1894 tree variants;
1900 variants;
1902 {
1903 /* These fields are in the _TYPE part of the node, not in
1904 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1914 /* Copy whatever these are holding today. */
1917 }
1918 }
1920 /* KLASS is a class that we're applying may_alias to after the body is
1921 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
1922 canonical type(s) will be implicitly updated. */
1924 static void
1926 {
1935 }
1937 /* Early variant fixups: we apply attributes at the beginning of the class
1938 definition, and we need to fix up any variants that have already been
1939 made via elaborated-type-specifier so that check_qualified_type works. */
1941 void
1943 {
1944 tree variants;
1958 variants;
1960 {
1961 /* These are the two fields that check_qualified_type looks at and
1962 are affected by attributes. */
1967 else
1972 }
1973 }
1974 \f
1975 /* Set memoizing fields and bits of T (and its variants) for later
1976 use. */
1978 static void
1980 {
1981 /* Fix up variants (if any). */
1985 /* For a class w/o baseclasses, 'finish_struct' has set
1986 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
1987 Similarly for a class whose base classes do not have vtables.
1988 When neither of these is true, we might have removed abstract
1989 virtuals (by providing a definition), added some (by declaring
1990 new ones), or redeclared ones from a base class. We need to
1991 recalculate what's really an abstract virtual at this point (by
1992 looking in the vtables). */
1995 /* If this type has a copy constructor or a destructor, force its
1996 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
1997 nonzero. This will cause it to be passed by invisible reference
1998 and prevent it from being returned in a register. */
2001 {
2002 tree variants;
2005 {
2008 }
2009 }
2010 }
2012 /* Issue warnings about T having private constructors, but no friends,
2013 and so forth.
2015 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2016 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2017 non-private static member functions. */
2019 static void
2021 {
2026 /* If the class has friends, those entities might create and
2027 access instances, so we should not warn. */
2030 /* We will have warned when the template was declared; there's
2031 no need to warn on every instantiation. */
2033 /* There's no reason to even consider warning about this
2034 class. */
2037 /* We only issue one warning, if more than one applies, because
2038 otherwise, on code like:
2040 class A {
2041 // Oops - forgot `public:'
2042 A();
2043 A(const A&);
2044 ~A();
2045 };
2047 we warn several times about essentially the same problem. */
2049 /* Check to see if all (non-constructor, non-destructor) member
2050 functions are private. (Since there are no friends or
2051 non-private statics, we can't ever call any of the private member
2052 functions.) */
2057 /* We're not interested in compiler-generated methods; they don't
2060 {
2062 /* A non-private static member function is just like a
2063 friend; it can create and invoke private member
2064 functions, and be accessed without a class
2065 instance. */
2069 /* Keep searching for a static member function. */
2070 }
2075 {
2076 /* There are no non-private methods, and there's at least one
2077 private member function that isn't a constructor or
2078 destructor. (If all the private members are
2079 constructors/destructors we want to use the code below that
2080 issues error messages specifically referring to
2081 constructors/destructors.) */
2087 {
2090 }
2092 {
2096 }
2097 }
2099 /* Even if some of the member functions are non-private, the class
2100 won't be useful for much if all the constructors or destructors
2101 are private: such an object can never be created or destroyed. */
2104 {
2107 t);
2109 }
2111 /* Warn about classes that have private constructors and no friends. */
2113 /* Implicitly generated constructors are always public. */
2115 {
2119 /* If a non-template class does not define a copy
2120 constructor, one is defined for it, enabling it to avoid
2121 this warning. For a template class, this does not
2122 happen, and so we would normally get a warning on:
2124 template <class T> class C { private: C(); };
2126 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2127 complete non-template or fully instantiated classes have this
2128 flag set. */
2131 else
2137 /* Ideally, we wouldn't count any constructor that takes
2138 an argument of the class type as a parameter, because
2139 such things cannot be used to construct an instance of
2140 the class unless you already have one. */
2142 else
2146 {
2149 t);
2155 }
2156 }
2157 }
2159 /* Make BINFO's vtable have N entries, including RTTI entries,
2160 vbase and vcall offsets, etc. Set its type and call the back end
2161 to lay it out. */
2163 static void
2165 {
2166 tree atype;
2167 tree vtable;
2172 /* We may have to grow the vtable. */
2175 {
2179 }
2180 }
2182 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2183 have the same signature. */
2185 int
2187 {
2188 /* One destructor overrides another if they are the same kind of
2189 destructor. */
2193 /* But a non-destructor never overrides a destructor, nor vice
2194 versa, nor do different kinds of destructors override
2195 one-another. For example, a complete object destructor does not
2196 override a deleting destructor. */
2205 {
2213 }
2215 }
2217 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2218 subobject. */
2220 static bool
2222 {
2223 tree probe;
2226 {
2230 /* If we meet a virtual base, we can't follow the inheritance
2231 any more. See if the complete type of DERIVED contains
2232 such a virtual base. */
2235 }
2237 }
2240 /* The function for which we are trying to find a final overrider. */
2241 tree fn;
2242 /* The base class in which the function was declared. */
2243 tree declaring_base;
2244 /* The candidate overriders. */
2245 tree candidates;
2246 /* Path to most derived. */
2248 };
2250 /* Add the overrider along the current path to FFOD->CANDIDATES.
2251 Returns true if an overrider was found; false otherwise. */
2253 static bool
2257 {
2258 tree method;
2260 /* If BINFO is not the most derived type, try a more derived class.
2261 A definition there will overrider a definition here. */
2263 {
2264 depth--;
2268 }
2272 {
2275 /* Remove any candidates overridden by this new function. */
2277 {
2278 /* If *CANDIDATE overrides METHOD, then METHOD
2279 cannot override anything else on the list. */
2282 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2285 else
2287 }
2289 /* Add the new function. */
2292 }
2295 }
2297 /* Called from find_final_overrider via dfs_walk. */
2299 static tree
2301 {
2309 }
2311 static tree
2313 {
2318 }
2320 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2321 FN and whose TREE_VALUE is the binfo for the base where the
2322 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2323 DERIVED) is the base object in which FN is declared. */
2325 static tree
2327 {
2328 find_final_overrider_data ffod;
2330 /* Getting this right is a little tricky. This is valid:
2332 struct S { virtual void f (); };
2333 struct T { virtual void f (); };
2334 struct U : public S, public T { };
2336 even though calling `f' in `U' is ambiguous. But,
2338 struct R { virtual void f(); };
2339 struct S : virtual public R { virtual void f (); };
2340 struct T : virtual public R { virtual void f (); };
2341 struct U : public S, public T { };
2343 is not -- there's no way to decide whether to put `S::f' or
2344 `T::f' in the vtable for `R'.
2346 The solution is to look at all paths to BINFO. If we find
2347 different overriders along any two, then there is a problem. */
2351 /* Determine the depth of the hierarchy. */
2362 /* If there was no winner, issue an error message. */
2367 }
2369 /* Return the index of the vcall offset for FN when TYPE is used as a
2370 virtual base. */
2372 static tree
2374 {
2376 tree_pair_p p;
2384 /* There should always be an appropriate index. */
2386 }
2388 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2389 dominated by T. FN is the old function; VIRTUALS points to the
2390 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2391 of that entry in the list. */
2393 static void
2396 {
2397 tree b;
2398 tree overrider;
2399 tree delta;
2400 tree virtual_base;
2401 tree first_defn;
2407 /* Find the nearest primary base (possibly binfo itself) which defines
2408 this function; this is the class the caller will convert to when
2409 calling FN through BINFO. */
2411 {
2416 /* The nearest definition is from a lost primary. */
2419 }
2422 /* Find the final overrider. */
2425 {
2428 }
2431 /* Check for adjusting covariant return types. */
2439 /* If the overrider is invalid, don't even try. */
2441 {
2442 /* If FN is a covariant thunk, we must figure out the adjustment
2443 to the final base FN was converting to. As OVERRIDER_TARGET might
2444 also be converting to the return type of FN, we have to
2445 combine the two conversions here. */
2452 {
2456 }
2457 else
2461 /* Find the equivalent binfo within the return type of the
2462 overriding function. We will want the vbase offset from
2463 there. */
2465 over_return);
2468 {
2469 /* There was no existing virtual thunk (which takes
2470 precedence). So find the binfo of the base function's
2471 return type within the overriding function's return type.
2472 Fortunately we know the covariancy is valid (it
2473 has already been checked), so we can just iterate along
2474 the binfos, which have been chained in inheritance graph
2475 order. Of course it is lame that we have to repeat the
2476 search here anyway -- we should really be caching pieces
2477 of the vtable and avoiding this repeated work. */
2480 /* Find the base binfo within the overriding function's
2481 return type. We will always find a thunk_binfo, except
2482 when the covariancy is invalid (which we will have
2483 already diagnosed). */
2486 thunk_binfo;
2492 /* See if virtual inheritance is involved. */
2494 virtual_offset;
2501 {
2505 {
2506 /* We convert via virtual base. Adjust the fixed
2507 offset to be from there. */
2508 offset =
2512 }
2514 /* There was an existing fixed offset, this must be
2515 from the base just converted to, and the base the
2516 FN was thunking to. */
2518 else
2520 }
2521 }
2524 /* Replace the overriding function with a covariant thunk. We
2525 will emit the overriding function in its own slot as
2526 well. */
2529 }
2530 else
2534 /* If we need a covariant thunk, then we may need to adjust first_defn.
2535 The ABI specifies that the thunks emitted with a function are
2536 determined by which bases the function overrides, so we need to be
2537 sure that we're using a thunk for some overridden base; even if we
2538 know that the necessary this adjustment is zero, there may not be an
2539 appropriate zero-this-adjustment thunk for us to use since thunks for
2540 overriding virtual bases always use the vcall offset.
2542 Furthermore, just choosing any base that overrides this function isn't
2543 quite right, as this slot won't be used for calls through a type that
2544 puts a covariant thunk here. Calling the function through such a type
2545 will use a different slot, and that slot is the one that determines
2546 the thunk emitted for that base.
2548 So, keep looking until we find the base that we're really overriding
2549 in this slot: the nearest primary base that doesn't use a covariant
2550 thunk in this slot. */
2552 {
2554 /* We already know that the overrider needs a covariant thunk. */
2557 {
2564 }
2566 }
2568 /* Assume that we will produce a thunk that convert all the way to
2569 the final overrider, and not to an intermediate virtual base. */
2572 /* See if we can convert to an intermediate virtual base first, and then
2573 use the vcall offset located there to finish the conversion. */
2575 {
2576 /* If we find the final overrider, then we can stop
2577 walking. */
2582 /* If we find a virtual base, and we haven't yet found the
2583 overrider, then there is a virtual base between the
2584 declaring base (first_defn) and the final overrider. */
2586 {
2589 }
2590 }
2592 /* Compute the constant adjustment to the `this' pointer. The
2593 `this' pointer, when this function is called, will point at BINFO
2594 (or one of its primary bases, which are at the same offset). */
2596 /* The `this' pointer needs to be adjusted from the declaration to
2597 the nearest virtual base. */
2602 /* If the nearest definition is in a lost primary, we don't need an
2603 entry in our vtable. Except possibly in a constructor vtable,
2604 if we happen to get our primary back. In that case, the offset
2605 will be zero, as it will be a primary base. */
2607 else
2608 /* The `this' pointer needs to be adjusted from pointing to
2609 BINFO to pointing at the base where the final overrider
2610 appears. */
2621 else
2625 }
2627 /* Called from modify_all_vtables via dfs_walk. */
2629 static tree
2631 {
2633 tree virtuals;
2634 tree old_virtuals;
2638 /* A base without a vtable needs no modification, and its bases
2639 are uninteresting. */
2644 /* Don't do the primary vtable, if it's new. */
2648 /* There's no need to modify the vtable for a non-virtual primary
2649 base; we're not going to use that vtable anyhow. We do still
2650 need to do this for virtual primary bases, as they could become
2651 non-primary in a construction vtable. */
2656 /* Now, go through each of the virtual functions in the virtual
2657 function table for BINFO. Find the final overrider, and update
2658 the BINFO_VIRTUALS list appropriately. */
2661 virtuals;
2665 binfo,
2670 }
2672 /* Update all of the primary and secondary vtables for T. Create new
2673 vtables as required, and initialize their RTTI information. Each
2674 of the functions in VIRTUALS is declared in T and may override a
2675 virtual function from a base class; find and modify the appropriate
2676 entries to point to the overriding functions. Returns a list, in
2677 declaration order, of the virtual functions that are declared in T,
2678 but do not appear in the primary base class vtable, and which
2679 should therefore be appended to the end of the vtable for T. */
2681 static tree
2683 {
2687 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2691 /* Update all of the vtables. */
2694 /* Add virtual functions not already in our primary vtable. These
2695 will be both those introduced by this class, and those overridden
2696 from secondary bases. It does not include virtuals merely
2697 inherited from secondary bases. */
2699 {
2704 {
2705 /* We don't need to adjust the `this' pointer when
2706 calling this function. */
2710 /* This is a function not already in our vtable. Keep it. */
2712 }
2713 else
2714 /* We've already got an entry for this function. Skip it. */
2716 }
2719 }
2721 /* Get the base virtual function declarations in T that have the
2722 indicated NAME. */
2724 static void
2726 {
2729 /* Find virtual functions in T with the indicated NAME. */
2731 {
2735 {
2738 }
2739 }
2746 {
2749 }
2750 }
2752 /* If this declaration supersedes the declaration of
2753 a method declared virtual in the base class, then
2754 mark this field as being virtual as well. */
2756 void
2758 {
2761 /* In [temp.mem] we have:
2763 A specialization of a member function template does not
2764 override a virtual function from a base class. */
2771 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2772 the error_mark_node so that we know it is an overriding
2773 function. */
2774 {
2781 }
2784 {
2790 }
2795 }
2797 /* Warn about hidden virtual functions that are not overridden in t.
2798 We know that constructors and destructors don't apply. */
2800 static void
2802 {
2805 {
2813 tree base_binfo;
2814 tree binfo;
2817 /* Iterate through all of the base classes looking for possibly
2818 hidden functions. */
2821 {
2824 }
2826 /* If there are no functions to hide, continue. */
2830 /* Remove any overridden functions. */
2832 {
2836 {
2837 /* If the method from the base class has the same
2838 signature as the method from the derived class, it
2839 has been overridden. */
2844 }
2845 }
2847 /* Now give a warning for all base functions without overriders,
2848 as they are hidden. */
2849 tree base_fndecl;
2852 {
2853 /* Here we know it is a hider, and no overrider exists. */
2855 OPT_Woverloaded_virtual,
2859 }
2860 }
2861 }
2863 /* Recursive helper for finish_struct_anon. */
2865 static void
2867 {
2871 {
2872 /* We're generally only interested in entities the user
2873 declared, but we also find nested classes by noticing
2874 the TYPE_DECL that we create implicitly. You're
2875 allowed to put one anonymous union inside another,
2876 though, so we explicitly tolerate that. We use
2877 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2878 we also allow unnamed types used for defining fields. */
2885 {
2886 /* We already complained about static data members in
2887 finish_static_data_member_decl. */
2889 {
2892 "%q#D invalid; an anonymous union can "
2894 else
2896 "%q#D invalid; an anonymous struct can "
2898 }
2900 }
2903 {
2905 {
2909 else
2912 }
2914 {
2918 else
2921 }
2922 }
2927 /* Recurse into the anonymous aggregates to handle correctly
2928 access control (c++/24926):
2930 class A {
2931 union {
2932 union {
2933 int i;
2934 };
2935 };
2936 };
2938 int j=A().i; */
2942 }
2943 }
2945 /* Check for things that are invalid. There are probably plenty of other
2946 things we should check for also. */
2948 static void
2950 {
2952 {
2961 }
2962 }
2964 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2965 will be used later during class template instantiation.
2966 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2967 a non-static member data (FIELD_DECL), a member function
2968 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2969 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2970 When FRIEND_P is nonzero, T is either a friend class
2971 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2972 (FUNCTION_DECL, TEMPLATE_DECL). */
2974 void
2976 {
2977 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2982 }
2984 /* This function is called from declare_virt_assop_and_dtor via
2985 dfs_walk_all.
2987 DATA is a type that direcly or indirectly inherits the base
2988 represented by BINFO. If BINFO contains a virtual assignment [copy
2989 assignment or move assigment] operator or a virtual constructor,
2990 declare that function in DATA if it hasn't been already declared. */
2992 static tree
2994 {
3002 /* A base without a vtable needs no modification, and its bases
3003 are uninteresting. */
3007 /* If this is a primary base, then we have already looked at the
3008 virtual functions of its vtable. */
3012 {
3016 {
3021 }
3025 }
3028 }
3030 /* If the class type T has a direct or indirect base that contains a
3031 virtual assignment operator or a virtual destructor, declare that
3032 function in T if it hasn't been already declared. */
3034 static void
3036 {
3044 dfs_declare_virt_assop_and_dtor,
3046 }
3048 /* Declare the inheriting constructor for class T inherited from base
3049 constructor CTOR with the parameter array PARMS of size NPARMS. */
3051 static void
3053 {
3056 /* We don't declare an inheriting ctor that would be a default,
3057 copy or move ctor for derived or base. */
3062 {
3066 }
3075 {
3078 }
3079 }
3081 /* Declare all the inheriting constructors for class T inherited from base
3082 constructor CTOR. */
3084 static void
3086 {
3090 {
3096 }
3101 {
3105 }
3108 {
3112 }
3113 }
3115 /* Create default constructors, assignment operators, and so forth for
3116 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3117 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3118 the class cannot have a default constructor, copy constructor
3119 taking a const reference argument, or an assignment operator taking
3120 a const reference, respectively. */
3122 static void
3126 {
3127 /* Destructor. */
3129 /* In general, we create destructors lazily. */
3138 /* [class.ctor]
3140 If there is no user-declared constructor for a class, a default
3141 constructor is implicitly declared. */
3143 {
3148 /* Don't force the declaration to get a hard answer; if the
3149 definition would have made the class non-literal, it will still be
3150 non-literal because of the base or member in question, and that
3151 gives a better diagnostic. */
3153 }
3155 /* [class.ctor]
3157 If a class definition does not explicitly declare a copy
3158 constructor, one is declared implicitly. */
3160 {
3166 }
3168 /* If there is no assignment operator, one will be created if and
3169 when it is needed. For now, just record whether or not the type
3170 of the parameter to the assignment operator will be a const or
3171 non-const reference. */
3173 {
3179 }
3181 /* We can't be lazy about declaring functions that might override
3182 a virtual function from a base class. */
3186 {
3190 {
3191 /* declare, then remove the decl */
3199 }
3200 else
3202 }
3203 }
3205 /* FIELD is a bit-field. We are finishing the processing for its
3206 enclosing type. Issue any appropriate messages and set appropriate
3207 flags. Returns false if an error has been diagnosed. */
3209 static bool
3211 {
3213 tree w;
3215 /* Extract the declared width of the bitfield, which has been
3216 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3219 /* Remove the bit-field width indicator so that the rest of the
3220 compiler does not treat that value as a qualifier. */
3223 /* Detect invalid bit-field type. */
3225 {
3228 }
3229 else
3230 {
3232 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3235 /* detect invalid field size. */
3241 {
3244 }
3246 {
3249 }
3251 {
3254 }
3264 {
3270 }
3271 }
3274 {
3278 }
3279 else
3280 {
3281 /* Non-bit-fields are aligned for their type. */
3285 }
3286 }
3288 /* FIELD is a non bit-field. We are finishing the processing for its
3289 enclosing type T. Issue any appropriate messages and set appropriate
3290 flags. */
3292 static bool
3294 tree t,
3297 {
3301 /* In C++98 an anonymous union cannot contain any fields which would change
3302 the settings of CANT_HAVE_CONST_CTOR and friends. */
3304 ;
3305 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3306 structs. So, we recurse through their fields here. */
3308 {
3313 cant_have_const_ctor,
3314 no_const_asn_ref);
3315 }
3316 /* Check members with class type for constructors, destructors,
3317 etc. */
3319 {
3320 /* Never let anything with uninheritable virtuals
3321 make it through without complaint. */
3325 {
3330 field);
3335 field);
3337 {
3341 }
3342 }
3343 else
3344 {
3357 }
3366 }
3371 /* `build_class_init_list' does not recognize
3372 non-FIELD_DECLs. */
3376 }
3378 /* Check the data members (both static and non-static), class-scoped
3379 typedefs, etc., appearing in the declaration of T. Issue
3380 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3381 declaration order) of access declarations; each TREE_VALUE in this
3382 list is a USING_DECL.
3384 In addition, set the following flags:
3386 EMPTY_P
3387 The class is empty, i.e., contains no non-static data members.
3389 CANT_HAVE_CONST_CTOR_P
3390 This class cannot have an implicitly generated copy constructor
3391 taking a const reference.
3393 CANT_HAVE_CONST_ASN_REF
3394 This class cannot have an implicitly generated assignment
3395 operator taking a const reference.
3397 All of these flags should be initialized before calling this
3398 function.
3400 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3401 fields can be added by adding to this chain. */
3403 static void
3407 {
3415 /* Assume there are no access declarations. */
3417 /* Assume this class has no pointer members. */
3419 /* Assume none of the members of this class have default
3420 initializations. */
3424 {
3432 {
3433 /* Save the access declarations for our caller. */
3436 }
3443 /* FIXME: We should fold in the checking from check_methods. */
3446 /* If we've gotten this far, it's a data member, possibly static,
3447 or an enumerator. */
3451 /* When this goes into scope, it will be a non-local reference. */
3455 {
3456 /* [class.union] (C++98)
3458 If a union contains a static data member, or a member of
3459 reference type, the program is ill-formed.
3461 In C++11 [class.union] says:
3462 If a union contains a non-static data member of reference type
3463 the program is ill-formed. */
3465 {
3469 }
3472 {
3476 }
3477 }
3479 /* Perform error checking that did not get done in
3480 grokdeclarator. */
3482 {
3486 }
3488 {
3492 }
3500 /* Now it can only be a FIELD_DECL. */
3505 /* If at least one non-static data member is non-literal, the whole
3506 class becomes non-literal. Per Core/1453, volatile non-static
3507 data members and base classes are also not allowed.
3508 Note: if the type is incomplete we will complain later on. */
3513 /* A standard-layout class is a class that:
3514 ...
3515 has the same access control (Clause 11) for all non-static data members,
3516 ... */
3523 /* If this is of reference type, check if it needs an init. */
3525 {
3531 {
3532 /* ARM $12.6.2: [A member initializer list] (or, for an
3533 aggregate, initialization by a brace-enclosed list) is the
3534 only way to initialize nonstatic const and reference
3535 members. */
3538 }
3539 }
3544 {
3546 {
3547 warning_at
3550 x);
3552 }
3556 }
3560 /* We don't treat zero-width bitfields as making a class
3561 non-empty. */
3562 ;
3563 else
3564 {
3565 /* The class is non-empty. */
3567 /* The class is not even nearly empty. */
3569 /* If one of the data members contains an empty class,
3570 so does T. */
3574 }
3576 /* This is used by -Weffc++ (see below). Warn only for pointers
3577 to members which might hold dynamic memory. So do not warn
3578 for pointers to functions or pointers to members. */
3584 {
3589 }
3595 {
3597 {
3601 }
3603 {
3607 }
3608 }
3611 /* DR 148 now allows pointers to members (which are POD themselves),
3612 to be allowed in POD structs. */
3621 /* We set DECL_C_BIT_FIELD in grokbitfield.
3622 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3627 {
3632 }
3634 /* Now that we've removed bit-field widths from DECL_INITIAL,
3635 anything left in DECL_INITIAL is an NSDMI that makes the class
3636 non-aggregate in C++11. */
3640 /* If any field is const, the structure type is pseudo-const. */
3642 {
3647 {
3648 /* ARM $12.6.2: [A member initializer list] (or, for an
3649 aggregate, initialization by a brace-enclosed list) is the
3650 only way to initialize nonstatic const and reference
3651 members. */
3654 }
3655 }
3656 /* A field that is pseudo-const makes the structure likewise. */
3658 {
3663 }
3665 /* Core issue 80: A nonstatic data member is required to have a
3666 different name from the class iff the class has a
3667 user-declared constructor. */
3672 }
3674 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3675 it should also define a copy constructor and an assignment operator to
3676 implement the correct copy semantic (deep vs shallow, etc.). As it is
3677 not feasible to check whether the constructors do allocate dynamic memory
3678 and store it within members, we approximate the warning like this:
3680 -- Warn only if there are members which are pointers
3681 -- Warn only if there is a non-trivial constructor (otherwise,
3682 there cannot be memory allocated).
3683 -- Warn only if there is a non-trivial destructor. We assume that the
3684 user at least implemented the cleanup correctly, and a destructor
3685 is needed to free dynamic memory.
3687 This seems enough for practical purposes. */
3689 && has_pointers
3693 {
3697 {
3702 }
3706 }
3708 /* Non-static data member initializers make the default constructor
3709 non-trivial. */
3711 {
3714 }
3716 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3720 /* Check anonymous struct/anonymous union fields. */
3723 /* We've built up the list of access declarations in reverse order.
3724 Fix that now. */
3726 }
3728 /* If TYPE is an empty class type, records its OFFSET in the table of
3729 OFFSETS. */
3731 static int
3733 {
3734 splay_tree_node n;
3739 /* Record the location of this empty object in OFFSETS. */
3747 type,
3751 }
3753 /* Returns nonzero if TYPE is an empty class type and there is
3754 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3756 static int
3758 {
3759 splay_tree_node n;
3760 tree t;
3765 /* Record the location of this empty object in OFFSETS. */
3775 }
3777 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3778 F for every subobject, passing it the type, offset, and table of
3779 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3780 be traversed.
3782 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3783 than MAX_OFFSET will not be walked.
3785 If F returns a nonzero value, the traversal ceases, and that value
3786 is returned. Otherwise, returns zero. */
3788 static int
3790 subobject_offset_fn f,
3791 tree offset,
3792 splay_tree offsets,
3793 tree max_offset,
3795 {
3799 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3800 stop. */
3808 {
3811 }
3814 {
3815 tree field;
3816 tree binfo;
3819 /* Avoid recursing into objects that are not interesting. */
3823 /* Record the location of TYPE. */
3828 /* Iterate through the direct base classes of TYPE. */
3832 {
3833 tree binfo_offset;
3838 tree orig_binfo;
3839 /* We cannot rely on BINFO_OFFSET being set for the base
3840 class yet, but the offsets for direct non-virtual
3841 bases can be calculated by going back to the TYPE. */
3844 offset,
3848 f,
3849 binfo_offset,
3850 offsets,
3851 max_offset,
3855 }
3858 {
3862 /* Iterate through the virtual base classes of TYPE. In G++
3863 3.2, we included virtual bases in the direct base class
3864 loop above, which results in incorrect results; the
3865 correct offsets for virtual bases are only known when
3866 working with the most derived type. */
3870 {
3872 f,
3874 offset,
3876 offsets,
3877 max_offset,
3881 }
3882 else
3883 {
3884 /* We still have to walk the primary base, if it is
3885 virtual. (If it is non-virtual, then it was walked
3886 above.) */
3892 {
3893 r = (walk_subobject_offsets
3898 }
3899 }
3900 }
3902 /* Iterate through the fields of TYPE. */
3907 {
3908 tree field_offset;
3913 f,
3915 offset,
3916 field_offset),
3917 offsets,
3918 max_offset,
3922 }
3923 }
3925 {
3928 tree index;
3930 /* Avoid recursing into objects that are not interesting. */
3933 || !domain
3937 /* Step through each of the elements in the array. */
3941 {
3943 f,
3944 offset,
3945 offsets,
3946 max_offset,
3952 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3953 there's no point in iterating through the remaining
3954 elements of the array. */
3957 }
3958 }
3961 }
3963 /* Record all of the empty subobjects of TYPE (either a type or a
3964 binfo). If IS_DATA_MEMBER is true, then a non-static data member
3965 is being placed at OFFSET; otherwise, it is a base class that is
3966 being placed at OFFSET. */
3968 static void
3970 tree offset,
3971 splay_tree offsets,
3973 {
3974 tree max_offset;
3975 /* If recording subobjects for a non-static data member or a
3976 non-empty base class , we do not need to record offsets beyond
3977 the size of the biggest empty class. Additional data members
3978 will go at the end of the class. Additional base classes will go
3979 either at offset zero (if empty, in which case they cannot
3980 overlap with offsets past the size of the biggest empty class) or
3981 at the end of the class.
3983 However, if we are placing an empty base class, then we must record
3984 all offsets, as either the empty class is at offset zero (where
3985 other empty classes might later be placed) or at the end of the
3986 class (where other objects might then be placed, so other empty
3987 subobjects might later overlap). */
3991 else
3995 }
3997 /* Returns nonzero if any of the empty subobjects of TYPE (located at
3998 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
3999 virtual bases of TYPE are examined. */
4001 static int
4003 tree offset,
4004 splay_tree offsets,
4006 {
4007 splay_tree_node max_node;
4009 /* Get the node in OFFSETS that indicates the maximum offset where
4010 an empty subobject is located. */
4012 /* If there aren't any empty subobjects, then there's no point in
4013 performing this check. */
4019 vbases_p);
4020 }
4022 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4023 non-static data member of the type indicated by RLI. BINFO is the
4024 binfo corresponding to the base subobject, OFFSETS maps offsets to
4025 types already located at those offsets. This function determines
4026 the position of the DECL. */
4028 static void
4030 tree decl,
4031 tree binfo,
4032 splay_tree offsets)
4033 {
4036 tree type;
4039 {
4040 /* For the purposes of determining layout conflicts, we want to
4041 use the class type of BINFO; TREE_TYPE (DECL) will be the
4042 CLASSTYPE_AS_BASE version, which does not contain entries for
4043 zero-sized bases. */
4046 }
4047 else
4048 {
4051 }
4053 /* Try to place the field. It may take more than one try if we have
4054 a hard time placing the field without putting two objects of the
4055 same type at the same address. */
4057 {
4060 /* Place this field. */
4064 /* We have to check to see whether or not there is already
4065 something of the same type at the offset we're about to use.
4066 For example, consider:
4068 struct S {};
4069 struct T : public S { int i; };
4070 struct U : public S, public T {};
4072 Here, we put S at offset zero in U. Then, we can't put T at
4073 offset zero -- its S component would be at the same address
4074 as the S we already allocated. So, we have to skip ahead.
4075 Since all data members, including those whose type is an
4076 empty class, have nonzero size, any overlap can happen only
4077 with a direct or indirect base-class -- it can't happen with
4078 a data member. */
4079 /* In a union, overlap is permitted; all members are placed at
4080 offset zero. */
4085 {
4086 /* Strip off the size allocated to this field. That puts us
4087 at the first place we could have put the field with
4088 proper alignment. */
4091 /* Bump up by the alignment required for the type. */
4092 rli->bitpos
4098 }
4101 {
4102 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4103 the offset wasn't aligned like a pointer when we started to
4104 layout this field, that affects its position. */
4107 {
4110 "alignment of %qD increased in -fabi-version=9 "
4112 else
4115 }
4117 }
4118 else
4119 /* There was no conflict. We're done laying out this field. */
4121 }
4123 /* Now that we know where it will be placed, update its
4124 BINFO_OFFSET. */
4126 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4127 this point because their BINFO_OFFSET is copied from another
4128 hierarchy. Therefore, we may not need to add the entire
4129 OFFSET. */
4135 }
4137 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4139 static int
4141 tree offset,
4143 {
4145 }
4147 /* Layout the empty base BINFO. EOC indicates the byte currently just
4148 past the end of the class, and should be correctly aligned for a
4149 class of the type indicated by BINFO; OFFSETS gives the offsets of
4150 the empty bases allocated so far. T is the most derived
4151 type. Return nonzero iff we added it at the end. */
4153 static bool
4156 {
4157 tree alignment;
4161 /* This routine should only be used for empty classes. */
4166 propagate_binfo_offsets
4170 /* This is an empty base class. We first try to put it at offset
4171 zero. */
4174 offsets,
4176 {
4177 /* That didn't work. Now, we move forward from the next
4178 available spot in the class. */
4182 {
4185 offsets,
4187 /* We finally found a spot where there's no overlap. */
4190 /* There's overlap here, too. Bump along to the next spot. */
4192 }
4193 }
4196 {
4201 }
4204 }
4206 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4207 fields at NEXT_FIELD, and return it. */
4209 static tree
4211 {
4212 /* Create the FIELD_DECL. */
4226 /* Add the new FIELD_DECL to the list of fields for T. */
4232 }
4234 /* Layout the base given by BINFO in the class indicated by RLI.
4235 *BASE_ALIGN is a running maximum of the alignments of
4236 any base class. OFFSETS gives the location of empty base
4237 subobjects. T is the most derived type. Return nonzero if the new
4238 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4239 *NEXT_FIELD, unless BINFO is for an empty base class.
4241 Returns the location at which the next field should be inserted. */
4246 {
4251 /* This error is now reported in xref_tag, thus giving better
4252 location information. */
4255 /* Place the base class. */
4257 {
4258 tree decl;
4260 /* The containing class is non-empty because it has a non-empty
4261 base class. */
4264 /* Create the FIELD_DECL. */
4267 /* Try to place the field. It may take more than one try if we
4268 have a hard time placing the field without putting two
4269 objects of the same type at the same address. */
4271 }
4272 else
4273 {
4274 tree eoc;
4277 /* On some platforms (ARM), even empty classes will not be
4278 byte-aligned. */
4283 /* A nearly-empty class "has no proper base class that is empty,
4284 not morally virtual, and at an offset other than zero." */
4286 {
4289 /* The check above (used in G++ 3.2) is insufficient because
4290 an empty class placed at offset zero might itself have an
4291 empty base at a nonzero offset. */
4293 empty_base_at_nonzero_offset_p,
4294 size_zero_node,
4299 }
4301 /* We used to not create a FIELD_DECL for empty base classes because of
4302 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4303 be a problem anymore. We need them to handle initialization of C++17
4304 aggregate bases. */
4306 {
4311 }
4313 /* An empty virtual base causes a class to be non-empty
4314 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4315 here because that was already done when the virtual table
4316 pointer was created. */
4317 }
4319 /* Record the offsets of BINFO and its base subobjects. */
4322 offsets,
4326 }
4328 /* Layout all of the non-virtual base classes. Record empty
4329 subobjects in OFFSETS. T is the most derived type. Return nonzero
4330 if the type cannot be nearly empty. The fields created
4331 corresponding to the base classes will be inserted at
4332 *NEXT_FIELD. */
4334 static void
4337 {
4338 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4339 subobjects. */
4344 /* The primary base class is always allocated first. */
4349 /* Now allocate the rest of the bases. */
4351 {
4352 tree base_binfo;
4356 /* The primary base was already allocated above, so we don't
4357 need to allocate it again here. */
4361 /* Virtual bases are added at the end (a primary virtual base
4362 will have already been added). */
4368 }
4369 }
4371 /* Go through the TYPE_FIELDS of T issuing any appropriate
4372 diagnostics, figuring out which methods override which other
4373 methods, and so forth. */
4375 static void
4377 {
4380 {
4386 /* The name of the field is the original field name
4387 Save this in auxiliary field for later overloading. */
4389 {
4393 }
4395 /* All user-provided destructors are non-trivial.
4396 Constructors and assignment ops are handled in
4397 grok_special_member_properties. */
4404 "%<transaction_safe_dynamic%> may only be specified for "
4406 }
4407 }
4409 /* FN is a constructor or destructor. Clone the declaration to create
4410 a specialized in-charge or not-in-charge version, as indicated by
4411 NAME. */
4413 static tree
4415 {
4416 tree parms;
4417 tree clone;
4419 /* Copy the function. */
4421 /* Reset the function name. */
4423 /* Remember where this function came from. */
4425 /* Make it easy to find the CLONE given the FN. */
4429 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4431 {
4438 }
4439 else
4440 {
4441 // Clone constraints.
4445 }
4450 /* There's no pending inline data for this function. */
4454 /* The base-class destructor is not virtual. */
4456 {
4460 }
4466 /* If there was an in-charge parameter, drop it from the function
4467 type. */
4469 {
4470 tree basetype;
4471 tree parmtypes;
4472 tree exceptions;
4477 /* Skip the `this' parameter. */
4479 /* Skip the in-charge parameter. */
4481 /* And the VTT parm, in a complete [cd]tor. */
4486 {
4487 /* If we're omitting inherited parms, that just leaves the VTT. */
4490 }
4494 parmtypes);
4497 exceptions);
4501 }
4503 /* Copy the function parameters. */
4505 /* Remove the in-charge parameter. */
4507 {
4511 }
4512 /* And the VTT parm, in a complete [cd]tor. */
4514 {
4517 else
4518 {
4522 }
4523 }
4525 /* A base constructor inheriting from a virtual base doesn't get the
4526 arguments. */
4531 {
4534 }
4536 /* Create the RTL for this function. */
4541 }
4543 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4544 not invoke this function directly.
4546 For a non-thunk function, returns the address of the slot for storing
4547 the function it is a clone of. Otherwise returns NULL_TREE.
4549 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4550 cloned_function is unset. This is to support the separate
4551 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4552 on a template makes sense, but not the former. */
4554 tree *
4556 {
4564 {
4565 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4568 else
4569 #endif
4571 }
4576 else
4578 }
4580 /* Produce declarations for all appropriate clones of FN. If
4581 UPDATE_METHODS is true, the clones are added to the
4582 CLASSTYPE_MEMBER_VEC. */
4584 void
4586 {
4587 tree clone;
4589 /* Avoid inappropriate cloning. */
4595 {
4596 /* For each constructor, we need two variants: an in-charge version
4597 and a not-in-charge version. */
4604 }
4605 else
4606 {
4609 /* For each destructor, we need three variants: an in-charge
4610 version, a not-in-charge version, and an in-charge deleting
4611 version. We clone the deleting version first because that
4612 means it will go second on the TYPE_FIELDS list -- and that
4613 corresponds to the correct layout order in the virtual
4614 function table.
4616 For a non-virtual destructor, we do not build a deleting
4617 destructor. */
4619 {
4623 }
4630 }
4632 /* Note that this is an abstract function that is never emitted. */
4634 }
4636 /* DECL is an in charge constructor, which is being defined. This will
4637 have had an in class declaration, from whence clones were
4638 declared. An out-of-class definition can specify additional default
4639 arguments. As it is the clones that are involved in overload
4640 resolution, we must propagate the information from the DECL to its
4641 clones. */
4643 void
4645 {
4646 tree clone;
4650 {
4657 /* Skip the 'this' parameter. */
4673 {
4675 {
4679 }
4685 {
4686 /* A default parameter has been added. Adjust the
4687 clone's parameters. */
4691 tree type;
4696 {
4699 clone_parms);
4701 }
4704 clone_parms);
4713 }
4714 }
4716 }
4717 }
4719 /* For each of the constructors and destructors in T, create an
4720 in-charge and not-in-charge variant. */
4722 static void
4724 {
4725 /* While constructors can be via a using declaration, at this point
4726 we no longer need to know that. */
4732 }
4734 /* Deduce noexcept for a destructor DTOR. */
4736 void
4738 {
4741 noexcept_deferred_spec);
4742 }
4744 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4745 of TYPE for virtual functions which FNDECL overrides. Return a
4746 mask of the tm attributes found therein. */
4748 static int
4750 {
4752 tree base_binfo;
4756 {
4764 {
4768 else
4771 }
4772 else
4774 }
4777 }
4779 /* Subroutine of set_method_tm_attributes. Handle the checks and
4780 inheritance for one virtual method FNDECL. */
4782 static void
4784 {
4785 tree tm_attr;
4790 /* If FNDECL doesn't actually override anything (i.e. T is the
4791 class that first declares FNDECL virtual), then we're done. */
4798 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4799 tm_pure must match exactly, otherwise no weakening of
4800 tm_safe > tm_callable > nothing. */
4801 /* ??? The tm_pure attribute didn't make the transition to the
4802 multivendor language spec. */
4804 {
4806 {
4809 }
4810 }
4811 /* If the overridden function is tm_pure, then FNDECL must be. */
4814 /* Look for base class combinations that cannot be satisfied. */
4816 {
4822 }
4823 /* If FNDECL did not declare an attribute, then inherit the most
4824 restrictive one. */
4826 {
4828 }
4829 /* Otherwise validate that we're not weaker than a function
4830 that is being overridden. */
4831 else
4832 {
4836 }
4839 err_override:
4843 }
4845 /* For each of the methods in T, propagate a class-level tm attribute. */
4847 static void
4849 {
4852 /* Don't bother collecting tm attributes if transactional memory
4853 support is not enabled. */
4857 /* Process virtual methods first, as they inherit directly from the
4858 base virtual function and also require validation of new attributes. */
4860 {
4861 tree vchain;
4864 {
4869 }
4870 }
4872 /* If the class doesn't have an attribute, nothing more to do. */
4877 /* Any method that does not yet have a tm attribute inherits
4878 the one from the class. */
4883 }
4885 /* Returns true if FN is a default constructor. */
4887 bool
4889 {
4892 }
4894 /* Returns true iff class T has a user-defined constructor that can be called
4895 with more than zero arguments. */
4897 bool
4899 {
4904 {
4911 }
4914 }
4916 /* Returns the defaulted constructor if T has one. Otherwise, returns
4917 NULL_TREE. */
4919 tree
4921 {
4926 {
4932 }
4935 }
4937 /* Returns true iff FN is a user-provided function, i.e. user-declared
4938 and not defaulted at its first declaration. */
4940 bool
4942 {
4945 else
4949 }
4951 /* Returns true iff class T has a user-provided constructor. */
4953 bool
4955 {
4967 }
4969 /* Returns true iff class T has a user-provided or explicit constructor. */
4971 bool
4973 {
4981 {
4985 }
4988 }
4990 /* Returns true iff class T has a non-user-provided (i.e. implicitly
4991 declared or explicitly defaulted in the class body) default
4992 constructor. */
4994 bool
4996 {
5003 {
5009 }
5012 }
5014 /* TYPE is being used as a virtual base, and has a non-trivial move
5015 assignment. Return true if this is due to there being a user-provided
5016 move assignment in TYPE or one of its subobjects; if there isn't, then
5017 multiple move assignment can't cause any harm. */
5019 bool
5021 {
5022 /* Does the type itself have a user-provided move assignment operator? */
5030 /* Do any of its bases? */
5032 tree base_binfo;
5037 /* Or non-static data members? */
5039 {
5044 }
5046 /* Seems not. */
5048 }
5050 /* If default-initialization leaves part of TYPE uninitialized, returns
5051 a DECL for the field or TYPE itself (DR 253). */
5053 tree
5055 {
5066 {
5070 }
5075 {
5079 }
5082 }
5084 /* Returns true iff for class T, a trivial synthesized default constructor
5085 would be constexpr. */
5087 bool
5089 {
5090 /* A defaulted trivial default constructor is constexpr
5091 if there is nothing to initialize. */
5094 }
5096 /* Returns true iff class T has a constexpr default constructor. */
5098 bool
5100 {
5101 tree fns;
5104 {
5105 /* The caller should have stripped an enclosing array. */
5108 }
5110 {
5113 /* Non-trivial, we need to check subobject constructors. */
5115 }
5118 }
5120 /* Returns true iff class T has a constexpr default constructor or has an
5121 implicitly declared default constructor that we can't tell if it's constexpr
5122 without forcing a lazy declaration (which might cause undesired
5123 instantiations). */
5125 bool
5127 {
5130 /* Assume it's constexpr. */
5133 }
5135 /* Returns true iff class TYPE has a virtual destructor. */
5137 bool
5139 {
5140 tree dtor;
5148 }
5150 /* Returns true iff T, a class, has a move-assignment or
5151 move-constructor. Does not lazily declare either.
5152 If USER_P is false, any move function will do. If it is true, the
5153 move function must be user-declared.
5155 Note that user-declared here is different from "user-provided",
5156 which doesn't include functions that are defaulted in the
5157 class. */
5159 bool
5161 {
5179 }
5181 /* Nonzero if we need to build up a constructor call when initializing an
5182 object of this class, either because it has a user-declared constructor
5183 or because it doesn't have a default constructor (so we need to give an
5184 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5185 what you care about is whether or not an object can be produced by a
5186 constructor (e.g. so we don't set TREE_READONLY on const variables of
5187 such type); use this function when what you care about is whether or not
5188 to try to call a constructor to create an object. The latter case is
5189 the former plus some cases of constructors that cannot be called. */
5191 bool
5193 {
5194 tree inner;
5204 /* A user-declared constructor might be private, and a constructor might
5205 be trivial but deleted. */
5208 {
5213 }
5215 }
5217 /* Like type_build_ctor_call, but for destructors. */
5219 bool
5221 {
5222 tree inner;
5231 /* A user-declared destructor might be private, and a destructor might
5232 be trivial but deleted. */
5235 {
5240 }
5242 }
5244 /* Remove all zero-width bit-fields from T. */
5246 static void
5248 {
5253 {
5256 /* We should not be confused by the fact that grokbitfield
5257 temporarily sets the width of the bit field into
5258 DECL_BIT_FIELD_REPRESENTATIVE (*fieldsp).
5259 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5260 to that width. */
5264 else
5266 }
5267 }
5269 /* Returns TRUE iff we need a cookie when dynamically allocating an
5270 array whose elements have the indicated class TYPE. */
5272 static bool
5274 {
5275 tree fns;
5280 /* If there's a non-trivial destructor, we need a cookie. In order
5281 to iterate through the array calling the destructor for each
5282 element, we'll have to know how many elements there are. */
5286 /* If the usual deallocation function is a two-argument whose second
5287 argument is of type `size_t', then we have to pass the size of
5288 the array to the deallocation function, so we will need to store
5289 a cookie. */
5293 /* If there are no `operator []' members, or the lookup is
5294 ambiguous, then we don't need a cookie. */
5297 /* Loop through all of the functions. */
5299 {
5302 /* See if this function is a one-argument delete function. If
5303 it is, then it will be the usual deallocation function. */
5307 /* Do not consider this function if its second argument is an
5308 ellipsis. */
5311 /* Otherwise, if we have a two-argument function and the second
5312 argument is `size_t', it will be the usual deallocation
5313 function -- unless there is one-argument function, too. */
5317 }
5320 }
5322 /* Finish computing the `literal type' property of class type T.
5324 At this point, we have already processed base classes and
5325 non-static data members. We need to check whether the copy
5326 constructor is trivial, the destructor is trivial, and there
5327 is a trivial default constructor or at least one constexpr
5328 constructor other than the copy constructor. */
5330 static void
5332 {
5333 tree fn;
5345 /* C++14 DR 1684 removed this restriction. */
5353 {
5357 "enclosing class of %<constexpr%> non-static member "
5360 }
5361 }
5363 /* T is a non-literal type used in a context which requires a constant
5364 expression. Explain why it isn't literal. */
5366 void
5368 {
5378 /* Already explained. */
5384 " %qT is a closure type, which is only literal in "
5392 {
5394 " %q+T is not an aggregate, does not have a trivial "
5395 "default constructor, and has no %<constexpr%> constructor that "
5398 /* Note that we can't simply call locate_ctor because when the
5399 constructor is deleted it just returns NULL_TREE. */
5401 {
5408 {
5411 else
5414 }
5415 }
5416 }
5417 else
5418 {
5422 {
5425 {
5431 }
5432 }
5434 {
5435 tree ftype;
5440 {
5443 field);
5446 }
5450 }
5451 }
5452 }
5454 /* Check the validity of the bases and members declared in T. Add any
5455 implicitly-generated functions (like copy-constructors and
5456 assignment operators). Compute various flag bits (like
5457 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5458 level: i.e., independently of the ABI in use. */
5460 static void
5462 {
5463 /* Nonzero if the implicitly generated copy constructor should take
5464 a non-const reference argument. */
5466 /* Nonzero if the implicitly generated assignment operator
5467 should take a non-const reference argument. */
5469 tree access_decls;
5472 tree fn;
5474 /* By default, we use const reference arguments and generate default
5475 constructors. */
5479 /* Check all the base-classes and set FMEM members to point to arrays
5480 of potential interest. */
5483 /* Deduce noexcept on destructor. This needs to happen after we've set
5484 triviality flags appropriately for our bases. */
5489 /* Check all the method declarations. */
5492 /* Save the initial values of these flags which only indicate whether
5493 or not the class has user-provided functions. As we analyze the
5494 bases and members we can set these flags for other reasons. */
5498 /* Check all the data member declarations. We cannot call
5499 check_field_decls until we have called check_bases check_methods,
5500 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5501 being set appropriately. */
5506 /* A nearly-empty class has to be vptr-containing; a nearly empty
5507 class contains just a vptr. */
5511 /* Do some bookkeeping that will guide the generation of implicitly
5512 declared member functions. */
5515 /* We need to call a constructor for this class if it has a
5516 user-provided constructor, or if the default constructor is going
5517 to initialize the vptr. (This is not an if-and-only-if;
5518 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5519 themselves need constructing.) */
5522 /* [dcl.init.aggr]
5524 An aggregate is an array or a class with no user-provided
5525 constructors ... and no virtual functions.
5527 Again, other conditions for being an aggregate are checked
5528 elsewhere. */
5532 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5533 retain the old definition internally for ABI reasons. */
5542 /* If the only explicitly declared default constructor is user-provided,
5543 set TYPE_HAS_COMPLEX_DFLT. */
5549 /* Warn if a public base of a polymorphic type has an accessible
5550 non-virtual destructor. It is only now that we know the class is
5551 polymorphic. Although a polymorphic base will have a already
5552 been diagnosed during its definition, we warn on use too. */
5554 {
5557 tree base_binfo;
5561 {
5569 basetype);
5570 }
5571 }
5573 /* If the class has no user-declared constructor, but does have
5574 non-static const or reference data members that can never be
5575 initialized, issue a warning. */
5577 /* Classes with user-declared constructors are presumed to
5578 initialize these members. */
5580 /* Aggregates can be initialized with brace-enclosed
5581 initializers. */
5583 {
5584 tree field;
5587 {
5588 tree type;
5605 }
5606 }
5608 /* Synthesize any needed methods. */
5610 cant_have_const_ctor,
5611 no_const_asn_ref);
5613 /* Check defaulted declarations here so we have cant_have_const_ctor
5614 and don't need to worry about clones. */
5619 {
5622 {
5623 bool imp_const_p
5629 /* If the function is defaulted outside the class, we just
5630 give the synthesis error. */
5633 }
5635 }
5638 {
5639 /* "This class type is not an aggregate." */
5641 }
5643 /* Compute the 'literal type' property before we
5644 do anything with non-static member functions. */
5647 /* Create the in-charge and not-in-charge variants of constructors
5648 and destructors. */
5651 /* Process the using-declarations. */
5655 /* Figure out whether or not we will need a cookie when dynamically
5656 allocating an array of this type. */
5659 }
5661 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5662 accordingly. If a new vfield was created (because T doesn't have a
5663 primary base class), then the newly created field is returned. It
5664 is not added to the TYPE_FIELDS list; it is the caller's
5665 responsibility to do that. Accumulate declared virtual functions
5666 on VIRTUALS_P. */
5668 static tree
5670 {
5671 tree fn;
5673 /* Collect the virtual functions declared in T. */
5678 {
5687 }
5689 /* If we couldn't find an appropriate base class, create a new field
5690 here. Even if there weren't any new virtual functions, we might need a
5691 new virtual function table if we're supposed to include vptrs in
5692 all classes that need them. */
5694 {
5695 /* We build this decl with vtbl_ptr_type_node, which is a
5696 `vtable_entry_type*'. It might seem more precise to use
5697 `vtable_entry_type (*)[N]' where N is the number of virtual
5698 functions. However, that would require the vtable pointer in
5699 base classes to have a different type than the vtable pointer
5700 in derived classes. We could make that happen, but that
5701 still wouldn't solve all the problems. In particular, the
5702 type-based alias analysis code would decide that assignments
5703 to the base class vtable pointer can't alias assignments to
5704 the derived class vtable pointer, since they have different
5705 types. Thus, in a derived class destructor, where the base
5706 class constructor was inlined, we could generate bad code for
5707 setting up the vtable pointer.
5709 Therefore, we use one type for all vtable pointers. We still
5710 use a type-correct type; it's just doesn't indicate the array
5711 bounds. That's better than using `void*' or some such; it's
5712 cleaner, and it let's the alias analysis code know that these
5713 stores cannot alias stores to void*! */
5714 tree field;
5727 /* This class is non-empty. */
5731 }
5734 }
5736 /* Add OFFSET to all base types of BINFO which is a base in the
5737 hierarchy dominated by T.
5739 OFFSET, which is a type offset, is number of bytes. */
5741 static void
5743 {
5745 tree primary_binfo;
5746 tree base_binfo;
5748 /* Update BINFO's offset. */
5753 offset));
5755 /* Find the primary base class. */
5761 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5762 downwards. */
5764 {
5765 /* Don't do the primary base twice. */
5773 }
5774 }
5776 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5777 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5778 empty subobjects of T. */
5780 static void
5782 {
5783 tree vbase;
5790 /* Find the last field. The artificial fields created for virtual
5791 bases will go after the last extant field to date. */
5796 /* Go through the virtual bases, allocating space for each virtual
5797 base that is not already a primary base class. These are
5798 allocated in inheritance graph order. */
5800 {
5805 {
5806 /* This virtual base is not a primary base of any class in the
5807 hierarchy, so we have to add space for it. */
5810 }
5811 }
5812 }
5814 /* Returns the offset of the byte just past the end of the base class
5815 BINFO. */
5817 static tree
5819 {
5820 tree size;
5825 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5826 allocate some space for it. It cannot have virtual bases, so
5827 TYPE_SIZE_UNIT is fine. */
5829 else
5833 }
5835 /* Returns the offset of the byte just past the end of the base class
5836 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
5837 only non-virtual bases are included. */
5839 static tree
5841 {
5844 tree binfo;
5845 tree base_binfo;
5846 tree offset;
5851 {
5861 }
5866 {
5870 }
5873 }
5875 /* Warn about bases of T that are inaccessible because they are
5876 ambiguous. For example:
5878 struct S {};
5879 struct T : public S {};
5880 struct U : public S, public T {};
5882 Here, `(S*) new U' is not allowed because there are two `S'
5883 subobjects of U. */
5885 static void
5887 {
5890 tree basetype;
5891 tree binfo;
5892 tree base_binfo;
5894 /* If there are no repeated bases, nothing can be ambiguous. */
5898 /* Check direct bases. */
5901 {
5907 }
5909 /* Check for ambiguous virtual bases. */
5913 {
5919 }
5920 }
5922 /* Compare two INTEGER_CSTs K1 and K2. */
5924 static int
5926 {
5928 }
5930 /* Increase the size indicated in RLI to account for empty classes
5931 that are "off the end" of the class. */
5933 static void
5935 {
5936 tree eoc;
5937 tree rli_size;
5939 /* It might be the case that we grew the class to allocate a
5940 zero-sized base class. That won't be reflected in RLI, yet,
5941 because we are willing to overlay multiple bases at the same
5942 offset. However, now we need to make sure that RLI is big enough
5943 to reflect the entire class. */
5948 {
5949 /* The size should have been rounded to a whole byte. */
5952 rli->bitpos
5961 }
5962 }
5964 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
5965 BINFO_OFFSETs for all of the base-classes. Position the vtable
5966 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
5968 static void
5970 {
5971 tree non_static_data_members;
5972 tree field;
5973 tree vptr;
5974 record_layout_info rli;
5975 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
5976 types that appear at that offset. */
5977 splay_tree empty_base_offsets;
5978 /* True if the last field laid out was a bit-field. */
5980 /* The location at which the next field should be inserted. */
5983 /* Keep track of the first non-static data member. */
5986 /* Start laying out the record. */
5989 /* Mark all the primary bases in the hierarchy. */
5992 /* Create a pointer to our virtual function table. */
5995 /* The vptr is always the first thing in the class. */
5997 {
6002 }
6003 else
6006 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6011 /* Layout the non-static data members. */
6013 {
6014 tree type;
6015 tree padding;
6017 /* We still pass things that aren't non-static data members to
6018 the back end, in case it wants to do something with them. */
6020 {
6022 /* If the static data member has incomplete type, keep track
6023 of it so that it can be completed later. (The handling
6024 of pending statics in finish_record_layout is
6025 insufficient; consider:
6027 struct S1;
6028 struct S2 { static S1 s1; };
6030 At this point, finish_record_layout will be called, but
6031 S1 is still incomplete.) */
6033 {
6035 /* The visibility of static data members is determined
6036 at their point of declaration, not their point of
6037 definition. */
6039 }
6041 }
6049 /* If this field is a bit-field whose width is greater than its
6050 type, then there are some special rules for allocating
6051 it. */
6054 {
6056 /* We must allocate the bits as if suitably aligned for the
6057 longest integer type that fits in this many bits. Then,
6058 we are supposed to use the left over bits as additional
6059 padding. */
6061 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6069 {
6071 /* Too big, so our current guess is what we want. */
6073 /* Not bigger than limit, ok */
6075 }
6077 /* Figure out how much additional padding is required. */
6079 /* In a union, the padding field must have the full width
6080 of the bit-field; all fields start at offset zero. */
6082 else
6089 /* An unnamed bitfield does not normally affect the
6090 alignment of the containing class on a target where
6091 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6092 make any exceptions for unnamed bitfields when the
6093 bitfields are longer than their types. Therefore, we
6094 temporarily give the field a name. */
6096 {
6099 }
6105 empty_base_offsets);
6108 /* Now that layout has been performed, set the size of the
6109 field to the size of its declared type; the rest of the
6110 field is effectively invisible. */
6112 /* We must also reset the DECL_MODE of the field. */
6114 }
6115 else
6117 empty_base_offsets);
6119 /* Remember the location of any empty classes in FIELD. */
6122 empty_base_offsets,
6125 /* If a bit-field does not immediately follow another bit-field,
6126 and yet it starts in the middle of a byte, we have failed to
6127 comply with the ABI. */
6130 /* The TREE_NO_WARNING flag gets set by Objective-C when
6131 laying out an Objective-C class. The ObjC ABI differs
6132 from the C++ ABI, and so we do not want a warning
6133 here. */
6135 && !last_field_was_bitfield
6138 bitsize_unit_node)))
6140 "offset of %qD is not ABI-compliant and may "
6143 /* The middle end uses the type of expressions to determine the
6144 possible range of expression values. In order to optimize
6145 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6146 must be made aware of the width of "i", via its type.
6148 Because C++ does not have integer types of arbitrary width,
6149 we must (for the purposes of the front end) convert from the
6150 type assigned here to the declared type of the bitfield
6151 whenever a bitfield expression is used as an rvalue.
6152 Similarly, when assigning a value to a bitfield, the value
6153 must be converted to the type given the bitfield here. */
6155 {
6160 {
6167 }
6168 }
6170 /* If we needed additional padding after this field, add it
6171 now. */
6173 {
6174 tree padding_field;
6177 FIELD_DECL,
6178 NULL_TREE,
6179 char_type_node);
6187 NULL_TREE,
6188 empty_base_offsets);
6189 }
6192 }
6195 {
6196 /* Make sure that we are on a byte boundary so that the size of
6197 the class without virtual bases will always be a round number
6198 of bytes. */
6201 }
6203 /* Delete all zero-width bit-fields from the list of fields. Now
6204 that the type is laid out they are no longer important. */
6208 {
6209 /* T needs a different layout as a base (eliding virtual bases
6210 or whatever). Create that version. */
6213 /* If the ABI version is not at least two, and the last
6214 field was a bit-field, RLI may not be on a byte
6215 boundary. In particular, rli_size_unit_so_far might
6216 indicate the last complete byte, while rli_size_so_far
6217 indicates the total number of bits used. Therefore,
6218 rli_size_so_far, rather than rli_size_unit_so_far, is
6219 used to compute TYPE_SIZE_UNIT. */
6227 eoc);
6237 /* Copy the non-static data members of T. This will include its
6238 direct non-virtual bases & vtable. */
6242 {
6246 }
6249 /* We use the base type for trivial assignments, and hence it
6250 needs a mode. */
6255 /* Record the base version of the type. */
6257 }
6258 else
6261 /* Every empty class contains an empty class. */
6265 /* Set the TYPE_DECL for this type to contain the right
6266 value for DECL_OFFSET, so that we can use it as part
6267 of a COMPONENT_REF for multiple inheritance. */
6270 /* Now fix up any virtual base class types that we left lying
6271 around. We must get these done before we try to lay out the
6272 virtual function table. As a side-effect, this will remove the
6273 base subobject fields. */
6276 /* Make sure that empty classes are reflected in RLI at this
6277 point. */
6280 /* Make sure not to create any structures with zero size. */
6286 /* If this is a non-POD, declaring it packed makes a difference to how it
6287 can be used as a field; don't let finalize_record_size undo it. */
6291 /* Let the back end lay out the type. */
6300 /* Warn about bases that can't be talked about due to ambiguity. */
6303 /* Now that we're done with layout, give the base fields the real types. */
6308 /* Clean up. */
6315 }
6317 /* Determine the "key method" for the class type indicated by TYPE,
6318 and set CLASSTYPE_KEY_METHOD accordingly. */
6320 void
6322 {
6323 tree method;
6330 /* The key method is the first non-pure virtual function that is not
6331 inline at the point of class definition. On some targets the
6332 key function may not be inline; those targets should not call
6333 this function until the end of the translation unit. */
6339 {
6342 }
6345 }
6347 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6348 class data member of non-zero size, otherwise false. */
6352 {
6360 {
6364 }
6367 }
6369 /* Used by find_flexarrays and related functions. */
6371 struct flexmems_t
6372 {
6373 /* The first flexible array member or non-zero array member found
6374 in the order of layout. */
6375 tree array;
6376 /* First non-static non-empty data member in the class or its bases. */
6377 tree first;
6378 /* The first non-static non-empty data member following either
6379 the flexible array member, if found, or the zero-length array member
6380 otherwise. AFTER[1] refers to the first such data member of a union
6381 of which the struct containing the flexible array member or zero-length
6382 array is a member, or NULL when no such union exists. This element is
6383 only used during searching, not for diagnosing problems. AFTER[0]
6384 refers to the first such data member that is not a member of such
6385 a union. */
6388 /* Refers to a struct (not union) in which the struct of which the flexible
6389 array is member is defined. Used to diagnose strictly (according to C)
6390 invalid uses of the latter structs. */
6391 tree enclosing;
6392 };
6394 /* Find either the first flexible array member or the first zero-length
6395 array, in that order of preference, among members of class T (but not
6396 its base classes), and set members of FMEM accordingly.
6397 BASE_P is true if T is a base class of another class.
6398 PUN is set to the outermost union in which the flexible array member
6399 (or zero-length array) is defined if one such union exists, otherwise
6400 to NULL.
6401 Similarly, PSTR is set to a data member of the outermost struct of
6402 which the flexible array is a member if one such struct exists,
6403 otherwise to NULL. */
6405 static void
6409 {
6410 /* Set the "pointer" to the outermost enclosing union if not set
6411 yet and maintain it for the remainder of the recursion. */
6416 {
6420 /* Is FLD a typedef for an anonymous struct? */
6422 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6423 handled elsewhere so that errors like the following are detected
6424 as well:
6425 typedef struct { int i, a[], j; } S; // bug c++/72753
6426 S s [2]; // bug c++/68489
6427 */
6432 {
6433 /* Check the nested unnamed type referenced via a typedef
6434 independently of FMEM (since it's not a data member of
6435 the enclosing class). */
6438 }
6440 /* Skip anything that's GCC-generated or not a (non-static) data
6441 member. */
6445 /* Type of the member. */
6450 /* Determine the type of the array element or object referenced
6451 by the member so that it can be checked for flexible array
6452 members if it hasn't been yet. */
6460 {
6462 {
6463 /* Once the member after the flexible array has been found
6464 we're done. */
6467 }
6470 {
6471 /* Descend into the non-static member struct or union and try
6472 to find a flexible array member or zero-length array among
6473 its members. This is only necessary for anonymous types
6474 and types in whose context the current type T has not been
6475 defined (the latter must not be checked again because they
6476 are already in the process of being checked by one of the
6477 recursive calls). */
6482 /* If this member isn't anonymous and a prior non-flexible array
6483 member has been seen in one of the enclosing structs, clear
6484 the FIRST member since it doesn't contribute to the flexible
6485 array struct's members. */
6496 {
6497 /* Restore the FIRST member reset above if no flexible
6498 array member has been found in this member's struct. */
6500 }
6502 /* If the member struct contains the first flexible array
6503 member, or if this member is a base class, continue to
6504 the next member and avoid setting the FMEM->NEXT pointer
6505 to point to it. */
6508 }
6509 }
6512 {
6513 /* Remember the first non-static data member. */
6517 /* Remember the first non-static data member after the flexible
6518 array member, if one has been found, or the zero-length array
6519 if it has been found. */
6522 }
6524 /* Skip non-arrays. */
6528 /* Determine the upper bound of the array if it has one. */
6530 {
6532 {
6533 /* Make a record of the zero-length array if either one
6534 such field or a flexible array member has been seen to
6535 handle the pathological and unlikely case of multiple
6536 such members. */
6539 }
6541 {
6542 /* Remember the first zero-length array unless a flexible array
6543 member has already been seen. */
6546 }
6547 }
6548 else
6549 {
6550 /* Flexible array members have no upper bound. */
6552 {
6554 {
6555 /* Replace the zero-length array if it's been stored and
6556 reset the after pointer. */
6560 }
6562 /* Make a record of another flexible array member. */
6564 }
6565 else
6566 {
6569 }
6570 }
6571 }
6572 }
6574 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6575 a flexible array member (or the zero-length array extension). */
6577 static void
6579 {
6591 }
6593 /* Issue diagnostics for invalid flexible array members or zero-length
6594 arrays that are not the last elements of the containing class or its
6595 base classes or that are its sole members. */
6597 static void
6599 {
6604 {
6607 }
6609 /* Has a diagnostic been issued? */
6615 {
6622 {
6626 {
6629 }
6630 }
6631 }
6632 else
6633 {
6640 {
6646 /* In the unlikely event that the member following the flexible
6647 array member is declared in a different class, or the member
6648 overlaps another member of a common union, point to it.
6649 Otherwise it should be obvious. */
6653 {
6658 }
6659 }
6660 }
6664 }
6667 /* Recursively check to make sure that any flexible array or zero-length
6668 array members of class T or its bases are valid (i.e., not the sole
6669 non-static data member of T and, if one exists, that it is the last
6670 non-static data member of T and its base classes. FMEM is expected
6671 to be initially null and is used internally by recursive calls to
6672 the function. Issue the appropriate diagnostics for the array member
6673 that fails the checks. */
6675 static void
6678 {
6679 /* Initialize the result of a search for flexible array and zero-length
6680 array members. Avoid doing any work if the most interesting FMEM data
6681 have already been populated. */
6690 /* Recursively check the primary base class first. */
6692 {
6695 }
6697 /* Recursively check the base classes. */
6700 {
6703 /* The primary base class was already checked above. */
6707 /* Virtual base classes are at the end. */
6711 /* Check the base class. */
6713 }
6716 {
6717 /* Check virtual base classes only once per derived class.
6718 I.e., this check is not performed recursively for base
6719 classes. */
6721 tree base_binfo;
6725 {
6726 /* Check the virtual base class. */
6730 }
6731 }
6733 /* Is the type unnamed (and therefore a member of it potentially
6734 an anonymous struct or union)? */
6737 /* Search the members of the current (possibly derived) class, skipping
6738 unnamed structs and unions since those could be anonymous. */
6743 {
6744 /* Issue diagnostics for invalid flexible and zero-length array
6745 members found in base classes or among the members of the current
6746 class. Ignore anonymous structs and unions whose members are
6747 considered to be members of the enclosing class and thus will
6748 be diagnosed when checking it. */
6750 }
6751 }
6753 /* Perform processing required when the definition of T (a class type)
6754 is complete. Diagnose invalid definitions of flexible array members
6755 and zero-size arrays. */
6757 void
6759 {
6760 tree x;
6761 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6765 {
6770 }
6772 /* If this type was previously laid out as a forward reference,
6773 make sure we lay it out again. */
6777 /* Make assumptions about the class; we'll reset the flags if
6778 necessary. */
6784 /* Do end-of-class semantic processing: checking the validity of the
6785 bases and members and add implicitly generated methods. */
6788 /* Find the key method. */
6790 {
6791 /* The Itanium C++ ABI permits the key method to be chosen when
6792 the class is defined -- even though the key method so
6793 selected may later turn out to be an inline function. On
6794 some systems (such as ARM Symbian OS) the key method cannot
6795 be determined until the end of the translation unit. On such
6796 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6797 will cause the class to be added to KEYED_CLASSES. Then, in
6798 finish_file we will determine the key method. */
6802 /* If a polymorphic class has no key method, we may emit the vtable
6803 in every translation unit where the class definition appears. If
6804 we're devirtualizing, we can look into the vtable even if we
6805 aren't emitting it. */
6808 }
6810 /* Layout the class itself. */
6812 /* COMPLETE_TYPE_P is now true. */
6816 /* With the layout complete, check for flexible array members and
6817 zero-length arrays that might overlap other members in the final
6818 layout. */
6823 /* If necessary, create the primary vtable for this class. */
6825 {
6826 /* We must enter these virtuals into the table. */
6830 /* Here we know enough to change the type of our virtual
6831 function table, but we will wait until later this function. */
6834 /* If we're warning about ABI tags, check the types of the new
6835 virtual functions. */
6839 }
6842 {
6844 tree fn;
6851 /* Add entries for virtual functions introduced by this class. */
6855 /* Set DECL_VINDEX for all functions declared in this class. */
6857 fn;
6859 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6861 {
6865 /* A thunk. We should never be calling this entry directly
6866 from this vtable -- we'd use the entry for the non
6867 thunk base function. */
6871 }
6872 }
6880 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
6881 for any static member objects of the type we're working on. */
6890 /* Complain if one of the field types requires lower visibility. */
6893 /* Make the rtl for any new vtables we have created, and unmark
6894 the base types we marked. */
6897 /* Build the VTT for T. */
6904 "%q#T has virtual functions and accessible"
6912 /* Class layout, assignment of virtual table slots, etc., is now
6913 complete. Give the back end a chance to tweak the visibility of
6914 the class or perform any other required target modifications. */
6924 /* Finish debugging output for this type. */
6928 {
6931 {
6934 }
6936 {
6939 else
6940 {
6943 }
6945 }
6947 {
6949 "the type of the first field has a different ABI from the "
6952 }
6953 }
6954 }
6956 /* When T was built up, the member declarations were added in reverse
6957 order. Rearrange them to declaration order. */
6959 void
6961 {
6962 tree next;
6963 tree prev;
6964 tree x;
6966 /* The following lists are all in reverse order. Put them in
6967 declaration order now. */
6970 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
6971 order, so we can't just use nreverse. Due to stat_hack
6972 chicanery in finish_member_declaration. */
6977 {
6981 }
6984 {
6987 }
6988 }
6990 tree
6992 {
6995 /* Now that we've got all the field declarations, reverse everything
6996 as necessary. */
7002 /* Nadger the current location so that diagnostics point to the start of
7003 the struct, not the end. */
7007 {
7008 tree x;
7010 /* We need to add the target functions of USING_DECLS, so that
7011 they can be found when the using declaration is not
7012 instantiated yet. */
7015 {
7020 }
7026 /* COMPLETE_TYPE_P is now true. */
7030 /* We need to emit an error message if this type was used as a parameter
7031 and it is an abstract type, even if it is a template. We construct
7032 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7033 account and we call complete_vars with this type, which will check
7034 the PARM_DECLS. Note that while the type is being defined,
7035 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7036 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7043 /* Remember current #pragma pack value. */
7046 /* Fix up any variants we've already built. */
7048 {
7052 }
7053 }
7054 else
7056 /* COMPLETE_TYPE_P is now true. */
7061 {
7062 /* People keep complaining that the compiler crashes on an invalid
7063 definition of initializer_list, so I guess we should explicitly
7064 reject it. What the compiler internals care about is that it's a
7065 template and has a pointer field followed by size_type field. */
7068 {
7071 {
7075 }
7076 }
7080 }
7088 else
7092 /* Lambdas are defined by the LAMBDA_EXPR. */
7097 }
7098 \f
7099 /* Hash table to avoid endless recursion when handling references. */
7102 /* Return the dynamic type of INSTANCE, if known.
7103 Used to determine whether the virtual function table is needed
7104 or not.
7106 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7107 of our knowledge of its type. *NONNULL should be initialized
7108 before this function is called. */
7110 static tree
7112 {
7113 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7116 {
7120 else
7124 /* This is a call to a constructor, hence it's never zero. */
7126 {
7130 }
7134 /* This is a call to a constructor, hence it's never zero. */
7136 {
7140 }
7149 /* Propagate nonnull. */
7154 CASE_CONVERT:
7160 {
7161 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7162 with a real object -- given &p->f, p can still be null. */
7164 /* ??? Probably should check DECL_WEAK here. */
7167 }
7171 /* If this component is really a base class reference, then the field
7172 itself isn't definitive. */
7181 {
7185 }
7186 /* fall through. */
7191 {
7195 }
7197 {
7201 /* if we're in a ctor or dtor, we know our type. If
7202 current_class_ptr is set but we aren't in a function, we're in
7203 an NSDMI (and therefore a constructor). */
7208 {
7212 }
7213 }
7215 {
7216 /* We only need one hash table because it is always left empty. */
7218 fixed_type_or_null_ref_ht
7221 /* Reference variables should be references to objects. */
7225 /* Enter the INSTANCE in a table to prevent recursion; a
7226 variable's initializer may refer to the variable
7227 itself. */
7232 {
7233 tree type;
7242 }
7243 }
7248 }
7249 #undef RECUR
7250 }
7252 /* Return nonzero if the dynamic type of INSTANCE is known, and
7253 equivalent to the static type. We also handle the case where
7254 INSTANCE is really a pointer. Return negative if this is a
7255 ctor/dtor. There the dynamic type is known, but this might not be
7256 the most derived base of the original object, and hence virtual
7257 bases may not be laid out according to this type.
7259 Used to determine whether the virtual function table is needed
7260 or not.
7262 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7263 of our knowledge of its type. *NONNULL should be initialized
7264 before this function is called. */
7266 int
7268 {
7271 tree fixed;
7273 /* processing_template_decl can be false in a template if we're in
7274 instantiate_non_dependent_expr, but we still want to suppress
7275 this check. */
7277 {
7278 /* In a template we only care about the type of the result. */
7282 }
7292 }
7294 \f
7295 void
7297 {
7300 current_class_stack
7308 }
7310 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7312 static void
7314 {
7315 tree type;
7317 /* We are re-entering the same class we just left, so we don't
7318 have to search the whole inheritance matrix to find all the
7319 decls to bind again. Instead, we install the cached
7320 class_shadowed list and walk through it binding names. */
7323 /* Restore IDENTIFIER_TYPE_VALUE. */
7325 type;
7328 }
7330 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7331 appropriate for TYPE.
7333 So that we may avoid calls to lookup_name, we cache the _TYPE
7334 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7336 For multiple inheritance, we perform a two-pass depth-first search
7337 of the type lattice. */
7339 void
7341 {
7342 class_stack_node_t csn;
7346 /* Make sure there is enough room for the new entry on the stack. */
7348 {
7350 current_class_stack
7352 current_class_stack_size);
7353 }
7355 /* Insert a new entry on the class stack. */
7362 current_class_depth++;
7364 /* Now set up the new type. */
7370 /* By default, things in classes are private, while things in
7371 structures or unions are public. */
7373 ? access_private_node
7379 {
7380 /* Forcibly remove any old class remnants. */
7382 }
7388 else
7390 }
7392 /* When we exit a toplevel class scope, we save its binding level so
7393 that we can restore it quickly. Here, we've entered some other
7394 class, so we must invalidate our cache. */
7396 void
7398 {
7400 }
7402 /* Get out of the current class scope. If we were in a class scope
7403 previously, that is the one popped to. */
7405 void
7407 {
7410 current_class_depth--;
7416 }
7418 /* Mark the top of the class stack as hidden. */
7420 void
7422 {
7425 }
7427 /* Mark the top of the class stack as un-hidden. */
7429 void
7431 {
7434 }
7436 /* Returns 1 if the class type currently being defined is either T or
7437 a nested type of T. Returns the type from the current_class_stack,
7438 which might be equivalent to but not equal to T in case of
7439 constrained partial specializations. */
7441 tree
7443 {
7451 /* We start looking from 1 because entry 0 is from global scope,
7452 and has no type. */
7454 {
7455 tree c;
7458 else
7459 {
7463 }
7468 }
7470 }
7472 /* If either current_class_type or one of its enclosing classes are derived
7473 from T, return the appropriate type. Used to determine how we found
7474 something via unqualified lookup. */
7476 tree
7478 {
7481 /* The bases of a dependent type are unknown. */
7492 {
7497 }
7500 }
7502 /* Return the outermost enclosing class type that is still open, or
7503 NULL_TREE. */
7505 tree
7507 {
7514 {
7521 }
7523 }
7525 /* Returns the innermost class type which is not a lambda closure type. */
7527 tree
7529 {
7534 }
7536 /* When entering a class scope, all enclosing class scopes' names with
7537 static meaning (static variables, static functions, types and
7538 enumerators) have to be visible. This recursive function calls
7539 pushclass for all enclosing class contexts until global or a local
7540 scope is reached. TYPE is the enclosed class. */
7542 void
7544 {
7545 /* A namespace might be passed in error cases, like A::B:C. */
7553 }
7555 /* Undoes a push_nested_class call. */
7557 void
7559 {
7565 }
7567 /* Returns the number of extern "LANG" blocks we are nested within. */
7569 int
7571 {
7573 }
7575 /* Set global variables CURRENT_LANG_NAME to appropriate value
7576 so that behavior of name-mangling machinery is correct. */
7578 void
7580 {
7587 else
7589 }
7591 /* Get out of the current language scope. */
7593 void
7595 {
7597 }
7598 \f
7599 /* Type instantiation routines. */
7601 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7602 matches the TARGET_TYPE. If there is no satisfactory match, return
7603 error_mark_node, and issue an error & warning messages under
7604 control of FLAGS. Permit pointers to member function if FLAGS
7605 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7606 a template-id, and EXPLICIT_TARGS are the explicitly provided
7607 template arguments.
7609 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7610 is the base path used to reference those member functions. If
7611 the address is resolved to a member function, access checks will be
7612 performed and errors issued if appropriate. */
7614 static tree
7616 tree overload,
7617 tsubst_flags_t complain,
7619 tree explicit_targs,
7620 tree access_path)
7621 {
7622 /* Here's what the standard says:
7624 [over.over]
7626 If the name is a function template, template argument deduction
7627 is done, and if the argument deduction succeeds, the deduced
7628 arguments are used to generate a single template function, which
7629 is added to the set of overloaded functions considered.
7631 Non-member functions and static member functions match targets of
7632 type "pointer-to-function" or "reference-to-function." Nonstatic
7633 member functions match targets of type "pointer-to-member
7634 function;" the function type of the pointer to member is used to
7635 select the member function from the set of overloaded member
7636 functions. If a nonstatic member function is selected, the
7637 reference to the overloaded function name is required to have the
7638 form of a pointer to member as described in 5.3.1.
7640 If more than one function is selected, any template functions in
7641 the set are eliminated if the set also contains a non-template
7642 function, and any given template function is eliminated if the
7643 set contains a second template function that is more specialized
7644 than the first according to the partial ordering rules 14.5.5.2.
7645 After such eliminations, if any, there shall remain exactly one
7646 selected function. */
7649 /* We store the matches in a TREE_LIST rooted here. The functions
7650 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7651 interoperability with most_specialized_instantiation. */
7653 tree fn;
7654 tree target_fn_type;
7656 /* By the time we get here, we should be seeing only real
7657 pointer-to-member types, not the internal POINTER_TYPE to
7658 METHOD_TYPE representation. */
7664 /* Check that the TARGET_TYPE is reasonable. */
7669 /* This is OK, too. */
7672 /* This is OK, too. This comes from a conversion to reference
7673 type. */
7675 else
7676 {
7682 }
7684 /* Non-member functions and static member functions match targets of type
7685 "pointer-to-function" or "reference-to-function." Nonstatic member
7686 functions match targets of type "pointer-to-member-function;" the
7687 function type of the pointer to member is used to select the member
7688 function from the set of overloaded member functions.
7690 So figure out the FUNCTION_TYPE that we want to match against. */
7693 /* If we can find a non-template function that matches, we can just
7694 use it. There's no point in generating template instantiations
7695 if we're just going to throw them out anyhow. But, of course, we
7696 can only do this when we don't *need* a template function. */
7699 {
7703 /* We're not looking for templates just yet. */
7707 /* We're looking for a non-static member, and this isn't
7708 one, or vice versa. */
7711 /* In C++17 we need the noexcept-qualifier to compare types. */
7716 /* See if there's a match. */
7721 }
7723 /* Now, if we've already got a match (or matches), there's no need
7724 to proceed to the template functions. But, if we don't have a
7725 match we need to look at them, too. */
7727 {
7728 tree target_arg_types;
7729 tree target_ret_type;
7732 tree arg;
7746 {
7748 tree instantiation;
7749 tree targs;
7752 /* We're only looking for templates. */
7757 /* We're not looking for a non-static member, and this is
7758 one, or vice versa. */
7763 /* If the template has a deduced return type, don't expose it to
7764 template argument deduction. */
7768 /* Try to do argument deduction. */
7775 /* Instantiation failed. */
7778 /* Constraints must be satisfied. This is done before
7779 return type deduction since that instantiates the
7780 function. */
7784 /* And now force instantiation to do return type deduction. */
7786 {
7792 }
7794 /* In C++17 we need the noexcept-qualifier to compare types. */
7798 /* See if there's a match. */
7803 }
7805 /* Now, remove all but the most specialized of the matches. */
7807 {
7812 NULL_TREE,
7813 NULL_TREE);
7814 }
7815 }
7817 /* Now we should have exactly one function in MATCHES. */
7819 {
7820 /* There were *no* matches. */
7822 {
7827 }
7829 }
7831 {
7832 /* There were too many matches. First check if they're all
7833 the same function. */
7838 /* For multi-versioned functions, more than one match is just fine and
7839 decls_match will return false as they are different. */
7847 {
7849 {
7853 /* Since print_candidates expects the functions in the
7854 TREE_VALUE slot, we flip them here. */
7859 }
7862 }
7863 }
7865 /* Good, exactly one match. Now, convert it to the correct type. */
7870 {
7878 {
7881 }
7882 }
7884 /* If a pointer to a function that is multi-versioned is requested, the
7885 pointer to the dispatcher function is returned instead. This works
7886 well because indirectly calling the function will dispatch the right
7887 function version at run-time. */
7889 {
7893 /* Mark all the versions corresponding to the dispatcher as used. */
7896 }
7898 /* If we're doing overload resolution purely for the purpose of
7899 determining conversion sequences, we should not consider the
7900 function used. If this conversion sequence is selected, the
7901 function will be marked as used at this point. */
7903 {
7904 /* Make =delete work with SFINAE. */
7909 }
7911 /* We could not check access to member functions when this
7912 expression was originally created since we did not know at that
7913 time to which function the expression referred. */
7915 {
7918 }
7922 else
7923 {
7924 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
7925 will mark the function as addressed, but here we must do it
7926 explicitly. */
7930 }
7931 }
7933 /* This function will instantiate the type of the expression given in
7934 RHS to match the type of LHSTYPE. If errors exist, then return
7935 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
7936 we complain on errors. If we are not complaining, never modify rhs,
7937 as overload resolution wants to try many possible instantiations, in
7938 the hope that at least one will work.
7940 For non-recursive calls, LHSTYPE should be a function, pointer to
7941 function, or a pointer to member function. */
7943 tree
7945 {
7952 {
7956 }
7959 {
7968 /* Microsoft allows `A::f' to be resolved to a
7969 pointer-to-member. */
7970 ;
7971 else
7972 {
7977 }
7978 }
7981 {
7984 }
7986 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
7987 deduce any type information. */
7989 {
7993 }
7995 /* If we instantiate a template, and it is a A ?: C expression
7996 with omitted B, look through the SAVE_EXPR. */
8000 /* There are only a few kinds of expressions that may have a type
8001 dependent on overload resolution. */
8007 /* This should really only be used when attempting to distinguish
8008 what sort of a pointer to function we have. For now, any
8009 arithmetic operation which is not supported on pointers
8010 is rejected as an error. */
8013 {
8015 {
8021 /* Do not lose object's side effects. */
8025 }
8032 /* This can happen if we are forming a pointer-to-member for a
8033 member template. */
8036 /* Fall through. */
8039 {
8043 return
8047 }
8051 return
8055 access_path);
8058 {
8063 }
8070 }
8072 }
8073 \f
8074 /* Return the name of the virtual function pointer field
8075 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8076 this may have to look back through base types to find the
8077 ultimate field name. (For single inheritance, these could
8078 all be the same name. Who knows for multiple inheritance). */
8080 static tree
8082 {
8088 {
8094 }
8102 }
8104 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8105 according to [class]:
8106 The class-name is also inserted
8107 into the scope of the class itself. For purposes of access checking,
8108 the inserted class name is treated as if it were a public member name. */
8110 void
8112 {
8129 }
8131 /* Returns 1 if TYPE contains only padding bytes. */
8133 int
8135 {
8143 }
8145 /* Returns true if TYPE contains no actual data, just various
8146 possible combinations of empty classes and possibly a vptr. */
8148 bool
8150 {
8152 {
8153 tree field;
8154 tree binfo;
8155 tree base_binfo;
8158 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8159 out, but we'd like to be able to check this before then. */
8170 /* An unnamed bit-field is not a data member. */
8175 }
8180 }
8182 /* Note that NAME was looked up while the current class was being
8183 defined and that the result of that lookup was DECL. */
8185 void
8187 {
8188 splay_tree names_used;
8190 /* If we're not defining a class, there's nothing to do. */
8196 /* If there's already a binding for this NAME, then we don't have
8197 anything to worry about. */
8210 }
8212 /* Note that NAME was declared (as DECL) in the current class. Check
8213 to see that the declaration is valid. */
8215 void
8217 {
8218 splay_tree names_used;
8219 splay_tree_node n;
8221 /* Look to see if we ever used this name. */
8222 names_used
8226 /* The C language allows members to be declared with a type of the same
8227 name, and the C++ standard says this diagnostic is not required. So
8228 allow it in extern "C" blocks unless predantic is specified.
8229 Allow it in all cases if -ms-extensions is specified. */
8235 {
8236 /* [basic.scope.class]
8238 A name N used in a class S shall refer to the same declaration
8239 in its context and when re-evaluated in the completed scope of
8240 S. */
8245 }
8246 }
8248 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8249 Secondary vtables are merged with primary vtables; this function
8250 will return the VAR_DECL for the primary vtable. */
8252 tree
8254 {
8255 tree decl;
8259 {
8262 }
8266 }
8269 /* Returns the binfo for the primary base of BINFO. If the resulting
8270 BINFO is a virtual base, and it is inherited elsewhere in the
8271 hierarchy, then the returned binfo might not be the primary base of
8272 BINFO in the complete object. Check BINFO_PRIMARY_P or
8273 BINFO_LOST_PRIMARY_P to be sure. */
8275 static tree
8277 {
8278 tree primary_base;
8285 }
8287 /* As above, but iterate until we reach the binfo that actually provides the
8288 vptr for BINFO. */
8290 static tree
8292 {
8296 {
8301 }
8303 }
8305 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8306 type. Note that the virtual inheritance might be above or below BINFO in
8307 the hierarchy. */
8309 bool
8311 {
8315 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8316 a morally virtual base. */
8319 }
8321 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8323 static int
8325 {
8329 }
8331 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8332 INDENT should be zero when called from the top level; it is
8333 incremented recursively. IGO indicates the next expected BINFO in
8334 inheritance graph ordering. */
8336 static tree
8338 dump_flags_t flags,
8339 tree binfo,
8340 tree igo,
8342 {
8344 tree base_binfo;
8352 {
8355 }
8370 {
8374 TFF_PLAIN_IDENTIFIER),
8376 }
8378 {
8381 }
8386 {
8390 {
8394 TFF_PLAIN_IDENTIFIER));
8395 }
8397 {
8401 TFF_PLAIN_IDENTIFIER));
8402 }
8404 {
8408 TFF_PLAIN_IDENTIFIER));
8409 }
8411 {
8415 TFF_PLAIN_IDENTIFIER));
8416 }
8420 }
8426 }
8428 /* Dump the BINFO hierarchy for T. */
8430 static void
8432 {
8444 }
8446 /* Debug interface to hierarchy dumping. */
8448 void
8450 {
8452 }
8454 static void
8456 {
8457 dump_flags_t flags;
8459 {
8462 }
8463 }
8465 static void
8467 {
8468 tree value;
8470 HOST_WIDE_INT elt;
8478 TFF_PLAIN_IDENTIFIER));
8485 }
8487 static void
8489 {
8490 dump_flags_t flags;
8497 {
8504 {
8509 }
8513 }
8516 }
8518 static void
8520 {
8521 dump_flags_t flags;
8528 {
8533 }
8536 }
8538 /* Dump a function or thunk and its thunkees. */
8540 static void
8542 {
8545 tree thunks;
8553 {
8563 else
8569 }
8573 }
8575 /* Dump the thunks for FN. */
8577 void
8579 {
8581 }
8583 /* Virtual function table initialization. */
8585 /* Create all the necessary vtables for T and its base classes. */
8587 static void
8589 {
8590 tree vbase;
8594 /* We lay out the primary and secondary vtables in one contiguous
8595 vtable. The primary vtable is first, followed by the non-virtual
8596 secondary vtables in inheritance graph order. */
8600 /* Then come the virtual bases, also in inheritance graph order. */
8602 {
8606 }
8610 }
8612 /* Initialize the vtable for BINFO with the INITS. */
8614 static void
8616 {
8617 tree decl;
8623 }
8625 /* Build the VTT (virtual table table) for T.
8626 A class requires a VTT if it has virtual bases.
8628 This holds
8629 1 - primary virtual pointer for complete object T
8630 2 - secondary VTTs for each direct non-virtual base of T which requires a
8631 VTT
8632 3 - secondary virtual pointers for each direct or indirect base of T which
8633 has virtual bases or is reachable via a virtual path from T.
8634 4 - secondary VTTs for each direct or indirect virtual base of T.
8636 Secondary VTTs look like complete object VTTs without part 4. */
8638 static void
8640 {
8641 tree type;
8642 tree vtt;
8643 tree index;
8646 /* Build up the initializers for the VTT. */
8651 /* If we didn't need a VTT, we're done. */
8655 /* Figure out the type of the VTT. */
8659 /* Now, build the VTT object itself. */
8662 /* Add the VTT to the vtables list. */
8667 }
8669 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8670 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8671 and CHAIN the vtable pointer for this binfo after construction is
8672 complete. VALUE can also be another BINFO, in which case we recurse. */
8674 static tree
8676 {
8677 tree vt;
8680 {
8686 else
8688 }
8691 }
8693 /* Data for secondary VTT initialization. */
8694 struct secondary_vptr_vtt_init_data
8695 {
8696 /* Is this the primary VTT? */
8699 /* Current index into the VTT. */
8700 tree index;
8702 /* Vector of initializers built up. */
8705 /* The type being constructed by this secondary VTT. */
8706 tree type_being_constructed;
8707 };
8709 /* Recursively build the VTT-initializer for BINFO (which is in the
8710 hierarchy dominated by T). INITS points to the end of the initializer
8711 list to date. INDEX is the VTT index where the next element will be
8712 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8713 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8714 for virtual bases of T. When it is not so, we build the constructor
8715 vtables for the BINFO-in-T variant. */
8717 static void
8720 {
8722 tree b;
8723 tree init;
8724 secondary_vptr_vtt_init_data data;
8727 /* We only need VTTs for subobjects with virtual bases. */
8731 /* We need to use a construction vtable if this is not the primary
8732 VTT. */
8734 {
8737 /* Record the offset in the VTT where this sub-VTT can be found. */
8739 }
8741 /* Add the address of the primary vtable for the complete object. */
8745 {
8748 }
8751 /* Recursively add the secondary VTTs for non-virtual bases. */
8756 /* Add secondary virtual pointers for all subobjects of BINFO with
8757 either virtual bases or reachable along a virtual path, except
8758 subobjects that are non-virtual primary bases. */
8768 /* data.inits might have grown as we added secondary virtual pointers.
8769 Make sure our caller knows about the new vector. */
8773 /* Add the secondary VTTs for virtual bases in inheritance graph
8774 order. */
8776 {
8781 }
8782 else
8783 /* Remove the ctor vtables we created. */
8785 }
8787 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8788 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8790 static tree
8792 {
8795 /* We don't care about bases that don't have vtables. */
8799 /* We're only interested in proper subobjects of the type being
8800 constructed. */
8804 /* We're only interested in bases with virtual bases or reachable
8805 via a virtual path from the type being constructed. */
8810 /* We're not interested in non-virtual primary bases. */
8814 /* Record the index where this secondary vptr can be found. */
8816 {
8821 {
8822 /* It's a primary virtual base, and this is not a
8823 construction vtable. Find the base this is primary of in
8824 the inheritance graph, and use that base's vtable
8825 now. */
8828 }
8829 }
8831 /* Add the initializer for the secondary vptr itself. */
8834 /* Advance the vtt index. */
8839 }
8841 /* Called from build_vtt_inits via dfs_walk. After building
8842 constructor vtables and generating the sub-vtt from them, we need
8843 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8844 binfo of the base whose sub vtt was generated. */
8846 static tree
8848 {
8852 /* If this class has no vtable, none of its bases do. */
8856 /* This might be a primary base, so have no vtable in this
8857 hierarchy. */
8860 /* If we scribbled the construction vtable vptr into BINFO, clear it
8861 out now. */
8867 }
8869 /* Build the construction vtable group for BINFO which is in the
8870 hierarchy dominated by T. */
8872 static void
8874 {
8875 tree type;
8876 tree vtbl;
8877 tree id;
8878 tree vbase;
8881 /* See if we've already created this construction vtable group. */
8887 /* Build a version of VTBL (with the wrong type) for use in
8888 constructing the addresses of secondary vtables in the
8889 construction vtable group. */
8892 /* Don't export construction vtables from shared libraries. Even on
8893 targets that don't support hidden visibility, this tells
8894 can_refer_decl_in_current_unit_p not to assume that it's safe to
8895 access from a different compilation unit (bz 54314). */
8903 /* Add the vtables for each of our virtual bases using the vbase in T
8904 binfo. */
8906 vbase;
8908 {
8909 tree b;
8916 }
8918 /* Figure out the type of the construction vtable. */
8925 /* Initialize the construction vtable. */
8929 }
8931 /* Add the vtbl initializers for BINFO (and its bases other than
8932 non-virtual primaries) to the list of INITS. BINFO is in the
8933 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
8934 the constructor the vtbl inits should be accumulated for. (If this
8935 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
8936 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
8937 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
8938 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
8939 but are not necessarily the same in terms of layout. */
8941 static void
8943 tree orig_binfo,
8944 tree rtti_binfo,
8945 tree vtbl,
8946 tree t,
8948 {
8950 tree base_binfo;
8955 /* If it doesn't have a vptr, we don't do anything. */
8959 /* If we're building a construction vtable, we're not interested in
8960 subobjects that don't require construction vtables. */
8966 /* Build the initializers for the BINFO-in-T vtable. */
8969 /* Walk the BINFO and its bases. We walk in preorder so that as we
8970 initialize each vtable we can figure out at what offset the
8971 secondary vtable lies from the primary vtable. We can't use
8972 dfs_walk here because we need to iterate through bases of BINFO
8973 and RTTI_BINFO simultaneously. */
8975 {
8976 /* Skip virtual bases. */
8982 inits);
8983 }
8984 }
8986 /* Called from accumulate_vtbl_inits. Adds the initializers for the
8987 BINFO vtable to L. */
8989 static void
8991 tree orig_binfo,
8992 tree rtti_binfo,
8993 tree orig_vtbl,
8994 tree t,
8996 {
9003 {
9004 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9005 primary virtual base. If it is not the same primary in
9006 the hierarchy of T, we'll need to generate a ctor vtable
9007 for it, to place at its location in T. If it is the same
9008 primary, we still need a VTT entry for the vtable, but it
9009 should point to the ctor vtable for the base it is a
9010 primary for within the sub-hierarchy of RTTI_BINFO.
9012 There are three possible cases:
9014 1) We are in the same place.
9015 2) We are a primary base within a lost primary virtual base of
9016 RTTI_BINFO.
9017 3) We are primary to something not a base of RTTI_BINFO. */
9019 tree b;
9022 /* First, look through the bases we are primary to for RTTI_BINFO
9023 or a virtual base. */
9026 {
9031 }
9032 /* If we run out of primary links, keep looking down our
9033 inheritance chain; we might be an indirect primary. */
9037 found:
9039 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9040 base B and it is a base of RTTI_BINFO, this is case 2. In
9041 either case, we share our vtable with LAST, i.e. the
9042 derived-most base within B of which we are a primary. */
9045 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9046 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9047 binfo_ctor_vtable after everything's been set up. */
9050 /* Otherwise, this is case 3 and we get our own. */
9051 }
9058 {
9059 tree index;
9062 /* Add the initializer for this vtable. */
9066 /* Figure out the position to which the VPTR should point. */
9072 }
9075 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9076 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9077 straighten this out. */
9080 /* Throw away any unneeded intializers. */
9082 else
9083 /* For an ordinary vtable, set BINFO_VTABLE. */
9085 }
9090 /* Construct the initializer for BINFO's virtual function table. BINFO
9091 is part of the hierarchy dominated by T. If we're building a
9092 construction vtable, the ORIG_BINFO is the binfo we should use to
9093 find the actual function pointers to put in the vtable - but they
9094 can be overridden on the path to most-derived in the graph that
9095 ORIG_BINFO belongs. Otherwise,
9096 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9097 BINFO that should be indicated by the RTTI information in the
9098 vtable; it will be a base class of T, rather than T itself, if we
9099 are building a construction vtable.
9101 The value returned is a TREE_LIST suitable for wrapping in a
9102 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9103 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9104 number of non-function entries in the vtable.
9106 It might seem that this function should never be called with a
9107 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9108 base is always subsumed by a derived class vtable. However, when
9109 we are building construction vtables, we do build vtables for
9110 primary bases; we need these while the primary base is being
9111 constructed. */
9113 static void
9115 tree orig_binfo,
9116 tree t,
9117 tree rtti_binfo,
9120 {
9121 tree v;
9122 vtbl_init_data vid;
9124 tree vbinfo;
9128 /* Initialize VID. */
9136 /* The first vbase or vcall offset is at index -3 in the vtable. */
9139 /* Add entries to the vtable for RTTI. */
9142 /* Create an array for keeping track of the functions we've
9143 processed. When we see multiple functions with the same
9144 signature, we share the vcall offsets. */
9146 /* Add the vcall and vbase offset entries. */
9149 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9150 build_vbase_offset_vtbl_entries. */
9155 /* If the target requires padding between data entries, add that now. */
9157 {
9162 /* Move data entries into their new positions and add padding
9163 after the new positions. Iterate backwards so we don't
9164 overwrite entries that we would need to process later. */
9167 ix--)
9168 {
9176 {
9180 null_pointer_node);
9181 }
9182 }
9183 }
9188 /* The initializers for virtual functions were built up in reverse
9189 order. Straighten them out and add them to the running list in one
9190 step. */
9199 /* Go through all the ordinary virtual functions, building up
9200 initializers. */
9202 {
9203 tree delta;
9204 tree vcall_index;
9211 {
9215 {
9218 }
9220 }
9222 /* If the only definition of this function signature along our
9223 primary base chain is from a lost primary, this vtable slot will
9224 never be used, so just zero it out. This is important to avoid
9225 requiring extra thunks which cannot be generated with the function.
9227 We first check this in update_vtable_entry_for_fn, so we handle
9228 restored primary bases properly; we also need to do it here so we
9229 zero out unused slots in ctor vtables, rather than filling them
9230 with erroneous values (though harmless, apart from relocation
9231 costs). */
9236 {
9237 /* Pull the offset for `this', and the function to call, out of
9238 the list. */
9245 /* You can't call an abstract virtual function; it's abstract.
9246 So, we replace these functions with __pure_virtual. */
9248 {
9251 {
9253 abort_fndecl_addr
9257 }
9258 }
9259 /* Likewise for deleted virtuals. */
9261 {
9263 {
9267 dvirt_fn = push_library_fn
9271 }
9276 }
9277 else
9278 {
9280 {
9285 }
9286 /* Take the address of the function, considering it to be of an
9287 appropriate generic type. */
9291 /* Don't refer to a virtual destructor from a constructor
9292 vtable or a vtable for an abstract class, since destroying
9293 an object under construction is undefined behavior and we
9294 don't want it to be considered a candidate for speculative
9295 devirtualization. But do create the thunk for ABI
9296 compliance. */
9301 }
9302 }
9304 /* And add it to the chain of initializers. */
9306 {
9311 else
9313 {
9319 }
9320 }
9321 else
9323 }
9324 }
9326 /* Adds to vid->inits the initializers for the vbase and vcall
9327 offsets in BINFO, which is in the hierarchy dominated by T. */
9329 static void
9331 {
9332 tree b;
9334 /* If this is a derived class, we must first create entries
9335 corresponding to the primary base class. */
9340 /* Add the vbase entries for this base. */
9342 /* Add the vcall entries for this base. */
9344 }
9346 /* Returns the initializers for the vbase offset entries in the vtable
9347 for BINFO (which is part of the class hierarchy dominated by T), in
9348 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9349 where the next vbase offset will go. */
9351 static void
9353 {
9354 tree vbase;
9355 tree t;
9356 tree non_primary_binfo;
9358 /* If there are no virtual baseclasses, then there is nothing to
9359 do. */
9365 /* We might be a primary base class. Go up the inheritance hierarchy
9366 until we find the most derived class of which we are a primary base:
9367 it is the offset of that which we need to use. */
9370 {
9371 tree b;
9373 /* If we have reached a virtual base, then it must be a primary
9374 base (possibly multi-level) of vid->binfo, or we wouldn't
9375 have called build_vcall_and_vbase_vtbl_entries for it. But it
9376 might be a lost primary, so just skip down to vid->binfo. */
9378 {
9381 }
9387 }
9389 /* Go through the virtual bases, adding the offsets. */
9391 vbase;
9393 {
9394 tree b;
9395 tree delta;
9400 /* Find the instance of this virtual base in the complete
9401 object. */
9404 /* If we've already got an offset for this virtual base, we
9405 don't need another one. */
9410 /* Figure out where we can find this vbase offset. */
9419 /* The vbase offset had better be the same. */
9422 /* The next vbase will come at a more negative offset. */
9426 /* The initializer is the delta from BINFO to this virtual base.
9427 The vbase offsets go in reverse inheritance-graph order, and
9428 we are walking in inheritance graph order so these end up in
9429 the right order. */
9436 }
9437 }
9439 /* Adds the initializers for the vcall offset entries in the vtable
9440 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9441 to VID->INITS. */
9443 static void
9445 {
9446 /* We only need these entries if this base is a virtual base. We
9447 compute the indices -- but do not add to the vtable -- when
9448 building the main vtable for a class. */
9451 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9452 correspond to VID->DERIVED), we are building a primary
9453 construction virtual table. Since this is a primary
9454 virtual table, we do not need the vcall offsets for
9455 BINFO. */
9457 {
9458 /* We need a vcall offset for each of the virtual functions in this
9459 vtable. For example:
9461 class A { virtual void f (); };
9462 class B1 : virtual public A { virtual void f (); };
9463 class B2 : virtual public A { virtual void f (); };
9464 class C: public B1, public B2 { virtual void f (); };
9466 A C object has a primary base of B1, which has a primary base of A. A
9467 C also has a secondary base of B2, which no longer has a primary base
9468 of A. So the B2-in-C construction vtable needs a secondary vtable for
9469 A, which will adjust the A* to a B2* to call f. We have no way of
9470 knowing what (or even whether) this offset will be when we define B2,
9471 so we store this "vcall offset" in the A sub-vtable and look it up in
9472 a "virtual thunk" for B2::f.
9474 We need entries for all the functions in our primary vtable and
9475 in our non-virtual bases' secondary vtables. */
9477 /* If we are just computing the vcall indices -- but do not need
9478 the actual entries -- not that. */
9481 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9483 }
9484 }
9486 /* Build vcall offsets, starting with those for BINFO. */
9488 static void
9490 {
9492 tree primary_binfo;
9493 tree base_binfo;
9495 /* Don't walk into virtual bases -- except, of course, for the
9496 virtual base for which we are building vcall offsets. Any
9497 primary virtual base will have already had its offsets generated
9498 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9502 /* If BINFO has a primary base, process it first. */
9507 /* Add BINFO itself to the list. */
9510 /* Scan the non-primary bases of BINFO. */
9514 }
9516 /* Called from build_vcall_offset_vtbl_entries_r. */
9518 static void
9520 {
9521 /* Make entries for the rest of the virtuals. */
9522 tree orig_fn;
9524 /* The ABI requires that the methods be processed in declaration
9525 order. */
9527 orig_fn;
9531 }
9533 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9535 static void
9537 {
9539 tree vcall_offset;
9540 tree derived_entry;
9542 /* If there is already an entry for a function with the same
9543 signature as FN, then we do not need a second vcall offset.
9544 Check the list of functions already present in the derived
9545 class vtable. */
9547 {
9549 /* We only use one vcall offset for virtual destructors,
9550 even though there are two virtual table entries. */
9554 }
9556 /* If we are building these vcall offsets as part of building
9557 the vtable for the most derived class, remember the vcall
9558 offset. */
9560 {
9563 }
9565 /* The next vcall offset will be found at a more negative
9566 offset. */
9570 /* Keep track of this function. */
9574 {
9575 tree base;
9576 tree fn;
9578 /* Find the overriding function. */
9582 else
9583 {
9586 /* The vbase we're working on is a primary base of
9587 vid->binfo. But it might be a lost primary, so its
9588 BINFO_OFFSET might be wrong, so we just use the
9589 BINFO_OFFSET from vid->binfo. */
9595 vcall_offset);
9596 }
9597 /* Add the initializer to the vtable. */
9599 }
9600 }
9602 /* Return vtbl initializers for the RTTI entries corresponding to the
9603 BINFO's vtable. The RTTI entries should indicate the object given
9604 by VID->rtti_binfo. */
9606 static void
9608 {
9609 tree b;
9610 tree t;
9611 tree offset;
9612 tree decl;
9613 tree init;
9617 /* To find the complete object, we will first convert to our most
9618 primary base, and then add the offset in the vtbl to that value. */
9623 /* The second entry is the address of the typeinfo object. */
9626 else
9629 /* Convert the declaration to a type that can be stored in the
9630 vtable. */
9634 /* Add the offset-to-top entry. It comes earlier in the vtable than
9635 the typeinfo entry. Convert the offset to look like a
9636 function pointer, so that we can put it in the vtable. */
9639 }
9641 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9642 accessibility. */
9644 bool
9646 {
9649 }
9651 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9653 bool
9655 {
9659 }
9661 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9662 class between them, if any. */
9664 tree
9666 {
9678 {
9681 }
9685 }