| blob | 3edae0f5e6193eced5df8bf7b75082d54086c960 |
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 {
1001 /* Check to see if we've already got this method. */
1003 {
1005 tree fn_type;
1006 tree method_type;
1007 tree parms1;
1008 tree parms2;
1013 /* Two using-declarations can coexist, we'll complain about ambiguity in
1014 overload resolution. */
1016 /* Except handle inherited constructors specially. */
1020 /* [over.load] Member function declarations with the
1021 same name and the same parameter types cannot be
1022 overloaded if any of them is a static member
1023 function declaration.
1025 [over.load] Member function declarations with the same name and
1026 the same parameter-type-list as well as member function template
1027 declarations with the same name, the same parameter-type-list, and
1028 the same template parameter lists cannot be overloaded if any of
1029 them, but not all, have a ref-qualifier.
1031 [namespace.udecl] When a using-declaration brings names
1032 from a base class into a derived class scope, member
1033 functions in the derived class override and/or hide member
1034 functions with the same name and parameter types in a base
1035 class (rather than conflicting). */
1041 /* Compare the quals on the 'this' parm. Don't compare
1042 the whole types, as used functions are treated as
1043 coming from the using class in overload resolution. */
1046 /* Either both or neither need to be ref-qualified for
1047 differing quals to allow overloading. */
1054 /* For templates, the return type and template parameters
1055 must be identical. */
1068 /* Bring back parameters omitted from an inherited ctor. */
1079 {
1080 /* If these are versions of the same function, process and
1081 move on. */
1087 {
1089 {
1093 {
1095 {
1096 /* Inheriting the same constructor along different
1097 paths, combine them. */
1098 SET_DECL_INHERITED_CTOR
1101 /* And discard the new one. */
1103 }
1104 else
1105 /* Inherited ctors can coexist until overload
1106 resolution. */
1108 }
1114 basef);
1115 }
1116 /* Otherwise defer to the other function. */
1118 }
1121 /* Defer to the local function. */
1125 {
1126 /* Remove the inherited constructor. */
1129 }
1130 else
1131 {
1137 }
1138 }
1139 }
1141 /* A class should never have more than one destructor. */
1153 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1159 }
1161 /* Subroutines of finish_struct. */
1163 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1164 legit, otherwise return 0. */
1166 static int
1168 {
1169 tree elem;
1177 {
1179 {
1183 else
1186 }
1187 else
1188 {
1189 /* They're changing the access to the same thing they changed
1190 it to before. That's OK. */
1191 ;
1192 }
1193 }
1194 else
1195 {
1197 tf_warning_or_error);
1200 }
1202 }
1204 /* Return the access node for DECL's access in its enclosing class. */
1206 tree
1208 {
1212 }
1214 /* Process the USING_DECL, which is a member of T. */
1216 static void
1218 {
1223 tree old_value;
1228 tf_warning_or_error);
1230 {
1235 else
1237 }
1245 ;
1247 {
1249 /* It's OK to use functions from a base when there are functions with
1251 else
1252 {
1259 }
1260 }
1262 {
1269 }
1271 /* Make type T see field decl FDECL with access ACCESS. */
1274 {
1277 }
1278 else
1280 }
1281 \f
1282 /* Data structure for find_abi_tags_r, below. */
1284 struct abi_tag_data
1285 {
1289 };
1291 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1292 in the context of P. TAG can be either an identifier (the DECL_NAME of
1293 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1295 static void
1297 {
1299 {
1301 {
1302 /* We're collecting tags from template arguments or from
1303 the type of a variable or function return type. */
1306 /* Don't inherit this tag multiple times. */
1310 {
1311 /* Tags inherited from type template arguments are only used
1312 to avoid warnings. */
1315 }
1316 /* For functions and variables we want to warn, too. */
1317 }
1319 /* Otherwise we're diagnosing missing tags. */
1321 {
1326 }
1328 {
1332 }
1334 {
1339 }
1340 else
1341 {
1345 {
1349 }
1350 }
1351 }
1352 }
1354 /* Find all the ABI tags in the attribute list ATTR and either call
1355 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1357 static void
1359 {
1366 {
1371 else
1373 }
1374 }
1376 /* Find all the ABI tags on T and its enclosing scopes and either call
1377 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1379 static void
1381 {
1383 {
1384 tree attr;
1386 {
1389 }
1390 else
1391 {
1394 }
1396 }
1397 }
1399 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1400 types with ABI tags, add the corresponding identifiers to the VEC in
1401 *DATA and set IDENTIFIER_MARKED. */
1403 static tree
1405 {
1409 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1410 anyway, but let's make sure of it. */
1418 }
1420 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1421 IDENTIFIER_MARKED on its ABI tags. */
1423 static tree
1425 {
1429 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1430 anyway, but let's make sure of it. */
1438 }
1440 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1441 scopes. */
1443 static void
1445 {
1448 {
1451 {
1452 /* Template arguments are part of the signature. */
1455 {
1458 }
1459 }
1461 /* A function's parameter types are part of the signature, so
1462 we don't need to inherit any tags that are also in them. */
1467 }
1468 }
1470 /* Check that T has all the ABI tags that subobject SUBOB has, or
1471 warn if not. If T is a (variable or function) declaration, also
1472 return any missing tags, and add them to T if JUST_CHECKING is false. */
1474 static tree
1476 {
1484 /* No need to worry about things local to this TU. */
1500 {
1503 }
1504 else
1505 {
1509 else
1513 }
1518 }
1520 /* Check that DECL has all the ABI tags that are used in parts of its type
1521 that are not reflected in its mangled name. */
1523 void
1525 {
1532 }
1534 /* Return any ABI tags that are used in parts of the type of DECL
1535 that are not reflected in its mangled name. This function is only
1536 used in backward-compatible mangling for ABI <11. */
1538 tree
1540 {
1544 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1545 that we can use this function for setting need_abi_warning
1546 regardless of the current flag_abi_version. */
1549 else
1551 }
1553 void
1555 {
1565 {
1568 {
1572 }
1573 }
1575 // If we found some tags on our template arguments, add them to our
1576 // abi_tag attribute.
1578 {
1582 else
1586 }
1589 }
1591 /* Return true, iff class T has a non-virtual destructor that is
1592 accessible from outside the class heirarchy (i.e. is public, or
1593 there's a suitable friend. */
1595 static bool
1597 {
1600 /* An implicitly declared destructor is always public. And,
1601 if it were virtual, we would have created it by now. */
1616 }
1618 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1619 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1620 properties of the bases. */
1622 static void
1626 {
1630 tree base_binfo;
1631 tree binfo;
1641 {
1650 /* If any base class is non-literal, so is the derived class. */
1654 /* If the base class doesn't have copy constructors or
1655 assignment operators that take const references, then the
1656 derived class cannot have such a member automatically
1657 generated. */
1666 /* A virtual base does not effect nearly emptiness. */
1667 ;
1669 {
1671 /* And if there is more than one nearly empty base, then the
1672 derived class is not nearly empty either. */
1674 else
1675 /* Remember we've seen one. */
1677 }
1679 /* If the base class is not empty or nearly empty, then this
1680 class cannot be nearly empty. */
1683 /* A lot of properties from the bases also apply to the derived
1684 class. */
1701 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1704 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1710 /* A standard-layout class is a class that:
1711 ...
1712 * has no non-standard-layout base classes, */
1715 {
1716 tree basefield;
1717 /* ...has no base classes of the same type as the first non-static
1718 data member... */
1720 && (same_type_ignoring_top_level_qualifiers_p
1723 else
1724 /* ...either has no non-static data members in the most-derived
1725 class and at most one base class with non-static data
1726 members, or has no base classes with non-static data
1727 members */
1733 {
1736 else
1739 }
1740 }
1742 /* Don't bother collecting tm attributes if transactional memory
1743 support is not enabled. */
1745 {
1749 }
1752 }
1754 /* If one of the base classes had TM attributes, and the current class
1755 doesn't define its own, then the current class inherits one. */
1757 {
1760 }
1761 }
1763 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1764 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1765 that have had a nearly-empty virtual primary base stolen by some
1766 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1767 T. */
1769 static void
1771 {
1775 tree base_binfo;
1777 /* Determine the primary bases of our bases. */
1780 {
1783 /* See if we're the non-virtual primary of our inheritance
1784 chain. */
1786 {
1793 /* We are the primary binfo. */
1795 }
1796 /* Determine if we have a virtual primary base, and mark it so.
1797 */
1799 {
1803 /* Someone already claimed this base. */
1805 else
1806 {
1807 tree delta;
1812 /* A virtual binfo might have been copied from within
1813 another hierarchy. As we're about to use it as a
1814 primary base, make sure the offsets match. */
1822 }
1823 }
1824 }
1826 /* First look for a dynamic direct non-virtual base. */
1828 {
1832 {
1835 }
1836 }
1838 /* A "nearly-empty" virtual base class can be the primary base
1839 class, if no non-virtual polymorphic base can be found. Look for
1840 a nearly-empty virtual dynamic base that is not already a primary
1841 base of something in the hierarchy. If there is no such base,
1842 just pick the first nearly-empty virtual base. */
1848 {
1850 {
1851 /* Found one that is not primary. */
1854 }
1856 /* Remember the first candidate. */
1858 }
1860 found:
1861 /* If we've got a primary base, use it. */
1863 {
1868 /* We are stealing a primary base. */
1872 {
1873 tree delta;
1876 /* A virtual binfo might have been copied from within
1877 another hierarchy. As we're about to use it as a primary
1878 base, make sure the offsets match. */
1883 }
1890 }
1891 }
1893 /* Update the variant types of T. */
1895 void
1897 {
1898 tree variants;
1904 variants;
1906 {
1907 /* These fields are in the _TYPE part of the node, not in
1908 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1918 /* Copy whatever these are holding today. */
1921 }
1922 }
1924 /* KLASS is a class that we're applying may_alias to after the body is
1925 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
1926 canonical type(s) will be implicitly updated. */
1928 static void
1930 {
1939 }
1941 /* Early variant fixups: we apply attributes at the beginning of the class
1942 definition, and we need to fix up any variants that have already been
1943 made via elaborated-type-specifier so that check_qualified_type works. */
1945 void
1947 {
1948 tree variants;
1962 variants;
1964 {
1965 /* These are the two fields that check_qualified_type looks at and
1966 are affected by attributes. */
1971 else
1976 }
1977 }
1978 \f
1979 /* Set memoizing fields and bits of T (and its variants) for later
1980 use. */
1982 static void
1984 {
1985 /* Fix up variants (if any). */
1989 /* For a class w/o baseclasses, 'finish_struct' has set
1990 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
1991 Similarly for a class whose base classes do not have vtables.
1992 When neither of these is true, we might have removed abstract
1993 virtuals (by providing a definition), added some (by declaring
1994 new ones), or redeclared ones from a base class. We need to
1995 recalculate what's really an abstract virtual at this point (by
1996 looking in the vtables). */
1999 /* If this type has a copy constructor or a destructor, force its
2000 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2001 nonzero. This will cause it to be passed by invisible reference
2002 and prevent it from being returned in a register. */
2005 {
2006 tree variants;
2009 {
2012 }
2013 }
2014 }
2016 /* Issue warnings about T having private constructors, but no friends,
2017 and so forth.
2019 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2020 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2021 non-private static member functions. */
2023 static void
2025 {
2030 /* If the class has friends, those entities might create and
2031 access instances, so we should not warn. */
2034 /* We will have warned when the template was declared; there's
2035 no need to warn on every instantiation. */
2037 /* There's no reason to even consider warning about this
2038 class. */
2041 /* We only issue one warning, if more than one applies, because
2042 otherwise, on code like:
2044 class A {
2045 // Oops - forgot `public:'
2046 A();
2047 A(const A&);
2048 ~A();
2049 };
2051 we warn several times about essentially the same problem. */
2053 /* Check to see if all (non-constructor, non-destructor) member
2054 functions are private. (Since there are no friends or
2055 non-private statics, we can't ever call any of the private member
2056 functions.) */
2061 /* We're not interested in compiler-generated methods; they don't
2064 {
2066 /* A non-private static member function is just like a
2067 friend; it can create and invoke private member
2068 functions, and be accessed without a class
2069 instance. */
2073 /* Keep searching for a static member function. */
2074 }
2079 {
2080 /* There are no non-private methods, and there's at least one
2081 private member function that isn't a constructor or
2082 destructor. (If all the private members are
2083 constructors/destructors we want to use the code below that
2084 issues error messages specifically referring to
2085 constructors/destructors.) */
2091 {
2094 }
2096 {
2100 }
2101 }
2103 /* Even if some of the member functions are non-private, the class
2104 won't be useful for much if all the constructors or destructors
2105 are private: such an object can never be created or destroyed. */
2108 {
2111 t);
2113 }
2115 /* Warn about classes that have private constructors and no friends. */
2117 /* Implicitly generated constructors are always public. */
2119 {
2123 /* If a non-template class does not define a copy
2124 constructor, one is defined for it, enabling it to avoid
2125 this warning. For a template class, this does not
2126 happen, and so we would normally get a warning on:
2128 template <class T> class C { private: C(); };
2130 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2131 complete non-template or fully instantiated classes have this
2132 flag set. */
2135 else
2141 /* Ideally, we wouldn't count any constructor that takes
2142 an argument of the class type as a parameter, because
2143 such things cannot be used to construct an instance of
2144 the class unless you already have one. */
2146 else
2150 {
2153 t);
2159 }
2160 }
2161 }
2163 /* Make BINFO's vtable have N entries, including RTTI entries,
2164 vbase and vcall offsets, etc. Set its type and call the back end
2165 to lay it out. */
2167 static void
2169 {
2170 tree atype;
2171 tree vtable;
2176 /* We may have to grow the vtable. */
2179 {
2183 }
2184 }
2186 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2187 have the same signature. */
2189 int
2191 {
2192 /* One destructor overrides another if they are the same kind of
2193 destructor. */
2197 /* But a non-destructor never overrides a destructor, nor vice
2198 versa, nor do different kinds of destructors override
2199 one-another. For example, a complete object destructor does not
2200 override a deleting destructor. */
2209 {
2217 }
2219 }
2221 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2222 subobject. */
2224 static bool
2226 {
2227 tree probe;
2230 {
2234 /* If we meet a virtual base, we can't follow the inheritance
2235 any more. See if the complete type of DERIVED contains
2236 such a virtual base. */
2239 }
2241 }
2244 /* The function for which we are trying to find a final overrider. */
2245 tree fn;
2246 /* The base class in which the function was declared. */
2247 tree declaring_base;
2248 /* The candidate overriders. */
2249 tree candidates;
2250 /* Path to most derived. */
2252 };
2254 /* Add the overrider along the current path to FFOD->CANDIDATES.
2255 Returns true if an overrider was found; false otherwise. */
2257 static bool
2261 {
2262 tree method;
2264 /* If BINFO is not the most derived type, try a more derived class.
2265 A definition there will overrider a definition here. */
2267 {
2268 depth--;
2272 }
2276 {
2279 /* Remove any candidates overridden by this new function. */
2281 {
2282 /* If *CANDIDATE overrides METHOD, then METHOD
2283 cannot override anything else on the list. */
2286 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2289 else
2291 }
2293 /* Add the new function. */
2296 }
2299 }
2301 /* Called from find_final_overrider via dfs_walk. */
2303 static tree
2305 {
2313 }
2315 static tree
2317 {
2322 }
2324 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2325 FN and whose TREE_VALUE is the binfo for the base where the
2326 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2327 DERIVED) is the base object in which FN is declared. */
2329 static tree
2331 {
2332 find_final_overrider_data ffod;
2334 /* Getting this right is a little tricky. This is valid:
2336 struct S { virtual void f (); };
2337 struct T { virtual void f (); };
2338 struct U : public S, public T { };
2340 even though calling `f' in `U' is ambiguous. But,
2342 struct R { virtual void f(); };
2343 struct S : virtual public R { virtual void f (); };
2344 struct T : virtual public R { virtual void f (); };
2345 struct U : public S, public T { };
2347 is not -- there's no way to decide whether to put `S::f' or
2348 `T::f' in the vtable for `R'.
2350 The solution is to look at all paths to BINFO. If we find
2351 different overriders along any two, then there is a problem. */
2355 /* Determine the depth of the hierarchy. */
2366 /* If there was no winner, issue an error message. */
2371 }
2373 /* Return the index of the vcall offset for FN when TYPE is used as a
2374 virtual base. */
2376 static tree
2378 {
2380 tree_pair_p p;
2388 /* There should always be an appropriate index. */
2390 }
2392 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2393 dominated by T. FN is the old function; VIRTUALS points to the
2394 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2395 of that entry in the list. */
2397 static void
2400 {
2401 tree b;
2402 tree overrider;
2403 tree delta;
2404 tree virtual_base;
2405 tree first_defn;
2411 /* Find the nearest primary base (possibly binfo itself) which defines
2412 this function; this is the class the caller will convert to when
2413 calling FN through BINFO. */
2415 {
2420 /* The nearest definition is from a lost primary. */
2423 }
2426 /* Find the final overrider. */
2429 {
2432 }
2435 /* Check for adjusting covariant return types. */
2443 /* If the overrider is invalid, don't even try. */
2445 {
2446 /* If FN is a covariant thunk, we must figure out the adjustment
2447 to the final base FN was converting to. As OVERRIDER_TARGET might
2448 also be converting to the return type of FN, we have to
2449 combine the two conversions here. */
2456 {
2460 }
2461 else
2465 /* Find the equivalent binfo within the return type of the
2466 overriding function. We will want the vbase offset from
2467 there. */
2469 over_return);
2472 {
2473 /* There was no existing virtual thunk (which takes
2474 precedence). So find the binfo of the base function's
2475 return type within the overriding function's return type.
2476 Fortunately we know the covariancy is valid (it
2477 has already been checked), so we can just iterate along
2478 the binfos, which have been chained in inheritance graph
2479 order. Of course it is lame that we have to repeat the
2480 search here anyway -- we should really be caching pieces
2481 of the vtable and avoiding this repeated work. */
2484 /* Find the base binfo within the overriding function's
2485 return type. We will always find a thunk_binfo, except
2486 when the covariancy is invalid (which we will have
2487 already diagnosed). */
2490 thunk_binfo;
2496 /* See if virtual inheritance is involved. */
2498 virtual_offset;
2505 {
2509 {
2510 /* We convert via virtual base. Adjust the fixed
2511 offset to be from there. */
2512 offset =
2516 }
2518 /* There was an existing fixed offset, this must be
2519 from the base just converted to, and the base the
2520 FN was thunking to. */
2522 else
2524 }
2525 }
2528 /* Replace the overriding function with a covariant thunk. We
2529 will emit the overriding function in its own slot as
2530 well. */
2533 }
2534 else
2538 /* If we need a covariant thunk, then we may need to adjust first_defn.
2539 The ABI specifies that the thunks emitted with a function are
2540 determined by which bases the function overrides, so we need to be
2541 sure that we're using a thunk for some overridden base; even if we
2542 know that the necessary this adjustment is zero, there may not be an
2543 appropriate zero-this-adjustment thunk for us to use since thunks for
2544 overriding virtual bases always use the vcall offset.
2546 Furthermore, just choosing any base that overrides this function isn't
2547 quite right, as this slot won't be used for calls through a type that
2548 puts a covariant thunk here. Calling the function through such a type
2549 will use a different slot, and that slot is the one that determines
2550 the thunk emitted for that base.
2552 So, keep looking until we find the base that we're really overriding
2553 in this slot: the nearest primary base that doesn't use a covariant
2554 thunk in this slot. */
2556 {
2558 /* We already know that the overrider needs a covariant thunk. */
2561 {
2568 }
2570 }
2572 /* Assume that we will produce a thunk that convert all the way to
2573 the final overrider, and not to an intermediate virtual base. */
2576 /* See if we can convert to an intermediate virtual base first, and then
2577 use the vcall offset located there to finish the conversion. */
2579 {
2580 /* If we find the final overrider, then we can stop
2581 walking. */
2586 /* If we find a virtual base, and we haven't yet found the
2587 overrider, then there is a virtual base between the
2588 declaring base (first_defn) and the final overrider. */
2590 {
2593 }
2594 }
2596 /* Compute the constant adjustment to the `this' pointer. The
2597 `this' pointer, when this function is called, will point at BINFO
2598 (or one of its primary bases, which are at the same offset). */
2600 /* The `this' pointer needs to be adjusted from the declaration to
2601 the nearest virtual base. */
2606 /* If the nearest definition is in a lost primary, we don't need an
2607 entry in our vtable. Except possibly in a constructor vtable,
2608 if we happen to get our primary back. In that case, the offset
2609 will be zero, as it will be a primary base. */
2611 else
2612 /* The `this' pointer needs to be adjusted from pointing to
2613 BINFO to pointing at the base where the final overrider
2614 appears. */
2625 else
2629 }
2631 /* Called from modify_all_vtables via dfs_walk. */
2633 static tree
2635 {
2637 tree virtuals;
2638 tree old_virtuals;
2642 /* A base without a vtable needs no modification, and its bases
2643 are uninteresting. */
2648 /* Don't do the primary vtable, if it's new. */
2652 /* There's no need to modify the vtable for a non-virtual primary
2653 base; we're not going to use that vtable anyhow. We do still
2654 need to do this for virtual primary bases, as they could become
2655 non-primary in a construction vtable. */
2660 /* Now, go through each of the virtual functions in the virtual
2661 function table for BINFO. Find the final overrider, and update
2662 the BINFO_VIRTUALS list appropriately. */
2665 virtuals;
2669 binfo,
2674 }
2676 /* Update all of the primary and secondary vtables for T. Create new
2677 vtables as required, and initialize their RTTI information. Each
2678 of the functions in VIRTUALS is declared in T and may override a
2679 virtual function from a base class; find and modify the appropriate
2680 entries to point to the overriding functions. Returns a list, in
2681 declaration order, of the virtual functions that are declared in T,
2682 but do not appear in the primary base class vtable, and which
2683 should therefore be appended to the end of the vtable for T. */
2685 static tree
2687 {
2691 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2695 /* Update all of the vtables. */
2698 /* Add virtual functions not already in our primary vtable. These
2699 will be both those introduced by this class, and those overridden
2700 from secondary bases. It does not include virtuals merely
2701 inherited from secondary bases. */
2703 {
2708 {
2709 /* We don't need to adjust the `this' pointer when
2710 calling this function. */
2714 /* This is a function not already in our vtable. Keep it. */
2716 }
2717 else
2718 /* We've already got an entry for this function. Skip it. */
2720 }
2723 }
2725 /* Get the base virtual function declarations in T that have the
2726 indicated NAME. */
2728 static void
2730 {
2733 /* Find virtual functions in T with the indicated NAME. */
2735 {
2739 {
2742 }
2743 }
2750 {
2753 }
2754 }
2756 /* If this declaration supersedes the declaration of
2757 a method declared virtual in the base class, then
2758 mark this field as being virtual as well. */
2760 void
2762 {
2765 /* In [temp.mem] we have:
2767 A specialization of a member function template does not
2768 override a virtual function from a base class. */
2775 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2776 the error_mark_node so that we know it is an overriding
2777 function. */
2778 {
2785 }
2788 {
2794 }
2799 }
2801 /* Warn about hidden virtual functions that are not overridden in t.
2802 We know that constructors and destructors don't apply. */
2804 static void
2806 {
2809 {
2817 tree base_binfo;
2818 tree binfo;
2821 /* Iterate through all of the base classes looking for possibly
2822 hidden functions. */
2825 {
2828 }
2830 /* If there are no functions to hide, continue. */
2834 /* Remove any overridden functions. */
2836 {
2840 {
2841 /* If the method from the base class has the same
2842 signature as the method from the derived class, it
2843 has been overridden. */
2848 }
2849 }
2851 /* Now give a warning for all base functions without overriders,
2852 as they are hidden. */
2853 tree base_fndecl;
2856 {
2857 /* Here we know it is a hider, and no overrider exists. */
2859 OPT_Woverloaded_virtual,
2863 }
2864 }
2865 }
2867 /* Recursive helper for finish_struct_anon. */
2869 static void
2871 {
2873 {
2874 /* We're generally only interested in entities the user
2875 declared, but we also find nested classes by noticing
2876 the TYPE_DECL that we create implicitly. You're
2877 allowed to put one anonymous union inside another,
2878 though, so we explicitly tolerate that. We use
2879 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2880 we also allow unnamed types used for defining fields. */
2889 {
2890 /* We already complained about static data members in
2891 finish_static_data_member_decl. */
2896 "only have public non-static data members"
2899 {
2902 {
2906 }
2907 }
2908 }
2913 /* Recurse into the anonymous aggregates to correctly handle
2914 access control (c++/24926):
2916 class A {
2917 union {
2918 union {
2919 int i;
2920 };
2921 };
2922 };
2924 int j=A().i; */
2928 }
2929 }
2931 /* Check for things that are invalid. There are probably plenty of other
2932 things we should check for also. */
2934 static void
2936 {
2938 {
2947 }
2948 }
2950 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2951 will be used later during class template instantiation.
2952 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2953 a non-static member data (FIELD_DECL), a member function
2954 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2955 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2956 When FRIEND_P is nonzero, T is either a friend class
2957 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2958 (FUNCTION_DECL, TEMPLATE_DECL). */
2960 void
2962 {
2963 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2968 }
2970 /* This function is called from declare_virt_assop_and_dtor via
2971 dfs_walk_all.
2973 DATA is a type that direcly or indirectly inherits the base
2974 represented by BINFO. If BINFO contains a virtual assignment [copy
2975 assignment or move assigment] operator or a virtual constructor,
2976 declare that function in DATA if it hasn't been already declared. */
2978 static tree
2980 {
2988 /* A base without a vtable needs no modification, and its bases
2989 are uninteresting. */
2993 /* If this is a primary base, then we have already looked at the
2994 virtual functions of its vtable. */
2998 {
3002 {
3007 }
3011 }
3014 }
3016 /* If the class type T has a direct or indirect base that contains a
3017 virtual assignment operator or a virtual destructor, declare that
3018 function in T if it hasn't been already declared. */
3020 static void
3022 {
3030 dfs_declare_virt_assop_and_dtor,
3032 }
3034 /* Declare the inheriting constructor for class T inherited from base
3035 constructor CTOR with the parameter array PARMS of size NPARMS. */
3037 static void
3039 {
3042 /* We don't declare an inheriting ctor that would be a default,
3043 copy or move ctor for derived or base. */
3048 {
3052 }
3061 {
3064 }
3065 }
3067 /* Declare all the inheriting constructors for class T inherited from base
3068 constructor CTOR. */
3070 static void
3072 {
3076 {
3082 }
3087 {
3091 }
3094 {
3098 }
3099 }
3101 /* Create default constructors, assignment operators, and so forth for
3102 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3103 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3104 the class cannot have a default constructor, copy constructor
3105 taking a const reference argument, or an assignment operator taking
3106 a const reference, respectively. */
3108 static void
3112 {
3113 /* Destructor. */
3115 /* In general, we create destructors lazily. */
3124 /* [class.ctor]
3126 If there is no user-declared constructor for a class, a default
3127 constructor is implicitly declared. */
3129 {
3134 /* Don't force the declaration to get a hard answer; if the
3135 definition would have made the class non-literal, it will still be
3136 non-literal because of the base or member in question, and that
3137 gives a better diagnostic. */
3139 }
3141 /* [class.ctor]
3143 If a class definition does not explicitly declare a copy
3144 constructor, one is declared implicitly. */
3146 {
3152 }
3154 /* If there is no assignment operator, one will be created if and
3155 when it is needed. For now, just record whether or not the type
3156 of the parameter to the assignment operator will be a const or
3157 non-const reference. */
3159 {
3165 }
3167 /* We can't be lazy about declaring functions that might override
3168 a virtual function from a base class. */
3172 {
3176 {
3177 /* declare, then remove the decl */
3185 }
3186 else
3188 }
3189 }
3191 /* FIELD is a bit-field. We are finishing the processing for its
3192 enclosing type. Issue any appropriate messages and set appropriate
3193 flags. Returns false if an error has been diagnosed. */
3195 static bool
3197 {
3199 tree w;
3201 /* Extract the declared width of the bitfield, which has been
3202 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3205 /* Remove the bit-field width indicator so that the rest of the
3206 compiler does not treat that value as a qualifier. */
3209 /* Detect invalid bit-field type. */
3211 {
3214 }
3215 else
3216 {
3218 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3221 /* detect invalid field size. */
3227 {
3230 }
3232 {
3235 }
3237 {
3240 }
3250 {
3256 }
3257 }
3260 {
3264 }
3265 else
3266 {
3267 /* Non-bit-fields are aligned for their type. */
3271 }
3272 }
3274 /* FIELD is a non bit-field. We are finishing the processing for its
3275 enclosing type T. Issue any appropriate messages and set appropriate
3276 flags. */
3278 static bool
3280 tree t,
3283 {
3287 /* In C++98 an anonymous union cannot contain any fields which would change
3288 the settings of CANT_HAVE_CONST_CTOR and friends. */
3290 ;
3291 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3292 structs. So, we recurse through their fields here. */
3294 {
3299 cant_have_const_ctor,
3300 no_const_asn_ref);
3301 }
3302 /* Check members with class type for constructors, destructors,
3303 etc. */
3305 {
3306 /* Never let anything with uninheritable virtuals
3307 make it through without complaint. */
3311 {
3316 field);
3321 field);
3323 {
3327 }
3328 }
3329 else
3330 {
3343 }
3352 }
3357 /* `build_class_init_list' does not recognize
3358 non-FIELD_DECLs. */
3362 }
3364 /* Check the data members (both static and non-static), class-scoped
3365 typedefs, etc., appearing in the declaration of T. Issue
3366 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3367 declaration order) of access declarations; each TREE_VALUE in this
3368 list is a USING_DECL.
3370 In addition, set the following flags:
3372 EMPTY_P
3373 The class is empty, i.e., contains no non-static data members.
3375 CANT_HAVE_CONST_CTOR_P
3376 This class cannot have an implicitly generated copy constructor
3377 taking a const reference.
3379 CANT_HAVE_CONST_ASN_REF
3380 This class cannot have an implicitly generated assignment
3381 operator taking a const reference.
3383 All of these flags should be initialized before calling this
3384 function.
3386 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3387 fields can be added by adding to this chain. */
3389 static void
3393 {
3401 /* Assume there are no access declarations. */
3403 /* Assume this class has no pointer members. */
3405 /* Assume none of the members of this class have default
3406 initializations. */
3410 {
3418 {
3419 /* Save the access declarations for our caller. */
3422 }
3429 /* FIXME: We should fold in the checking from check_methods. */
3432 /* If we've gotten this far, it's a data member, possibly static,
3433 or an enumerator. */
3437 /* When this goes into scope, it will be a non-local reference. */
3441 {
3442 /* [class.union] (C++98)
3444 If a union contains a static data member, or a member of
3445 reference type, the program is ill-formed.
3447 In C++11 [class.union] says:
3448 If a union contains a non-static data member of reference type
3449 the program is ill-formed. */
3451 {
3455 }
3458 {
3462 }
3463 }
3465 /* Perform error checking that did not get done in
3466 grokdeclarator. */
3468 {
3472 }
3474 {
3478 }
3486 /* Now it can only be a FIELD_DECL. */
3491 /* If at least one non-static data member is non-literal, the whole
3492 class becomes non-literal. Per Core/1453, volatile non-static
3493 data members and base classes are also not allowed.
3494 Note: if the type is incomplete we will complain later on. */
3499 /* A standard-layout class is a class that:
3500 ...
3501 has the same access control (Clause 11) for all non-static data members,
3502 ... */
3509 /* If this is of reference type, check if it needs an init. */
3511 {
3517 {
3518 /* ARM $12.6.2: [A member initializer list] (or, for an
3519 aggregate, initialization by a brace-enclosed list) is the
3520 only way to initialize nonstatic const and reference
3521 members. */
3524 }
3525 }
3530 {
3532 {
3533 warning_at
3536 x);
3538 }
3542 }
3546 /* We don't treat zero-width bitfields as making a class
3547 non-empty. */
3548 ;
3549 else
3550 {
3551 /* The class is non-empty. */
3553 /* The class is not even nearly empty. */
3555 /* If one of the data members contains an empty class,
3556 so does T. */
3560 }
3562 /* This is used by -Weffc++ (see below). Warn only for pointers
3563 to members which might hold dynamic memory. So do not warn
3564 for pointers to functions or pointers to members. */
3570 {
3575 }
3581 {
3583 {
3587 }
3589 {
3593 }
3594 }
3597 /* DR 148 now allows pointers to members (which are POD themselves),
3598 to be allowed in POD structs. */
3607 /* We set DECL_C_BIT_FIELD in grokbitfield.
3608 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3613 {
3618 }
3620 /* Now that we've removed bit-field widths from DECL_INITIAL,
3621 anything left in DECL_INITIAL is an NSDMI that makes the class
3622 non-aggregate in C++11. */
3626 /* If any field is const, the structure type is pseudo-const. */
3628 {
3633 {
3634 /* ARM $12.6.2: [A member initializer list] (or, for an
3635 aggregate, initialization by a brace-enclosed list) is the
3636 only way to initialize nonstatic const and reference
3637 members. */
3640 }
3641 }
3642 /* A field that is pseudo-const makes the structure likewise. */
3644 {
3649 }
3651 /* Core issue 80: A nonstatic data member is required to have a
3652 different name from the class iff the class has a
3653 user-declared constructor. */
3658 }
3660 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3661 it should also define a copy constructor and an assignment operator to
3662 implement the correct copy semantic (deep vs shallow, etc.). As it is
3663 not feasible to check whether the constructors do allocate dynamic memory
3664 and store it within members, we approximate the warning like this:
3666 -- Warn only if there are members which are pointers
3667 -- Warn only if there is a non-trivial constructor (otherwise,
3668 there cannot be memory allocated).
3669 -- Warn only if there is a non-trivial destructor. We assume that the
3670 user at least implemented the cleanup correctly, and a destructor
3671 is needed to free dynamic memory.
3673 This seems enough for practical purposes. */
3675 && has_pointers
3679 {
3683 {
3688 }
3692 }
3694 /* Non-static data member initializers make the default constructor
3695 non-trivial. */
3697 {
3700 }
3702 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3706 /* Check anonymous struct/anonymous union fields. */
3709 /* We've built up the list of access declarations in reverse order.
3710 Fix that now. */
3712 }
3714 /* If TYPE is an empty class type, records its OFFSET in the table of
3715 OFFSETS. */
3717 static int
3719 {
3720 splay_tree_node n;
3725 /* Record the location of this empty object in OFFSETS. */
3733 type,
3737 }
3739 /* Returns nonzero if TYPE is an empty class type and there is
3740 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3742 static int
3744 {
3745 splay_tree_node n;
3746 tree t;
3751 /* Record the location of this empty object in OFFSETS. */
3761 }
3763 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3764 F for every subobject, passing it the type, offset, and table of
3765 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3766 be traversed.
3768 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3769 than MAX_OFFSET will not be walked.
3771 If F returns a nonzero value, the traversal ceases, and that value
3772 is returned. Otherwise, returns zero. */
3774 static int
3776 subobject_offset_fn f,
3777 tree offset,
3778 splay_tree offsets,
3779 tree max_offset,
3781 {
3785 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3786 stop. */
3794 {
3797 }
3800 {
3801 tree field;
3802 tree binfo;
3805 /* Avoid recursing into objects that are not interesting. */
3809 /* Record the location of TYPE. */
3814 /* Iterate through the direct base classes of TYPE. */
3818 {
3819 tree binfo_offset;
3824 tree orig_binfo;
3825 /* We cannot rely on BINFO_OFFSET being set for the base
3826 class yet, but the offsets for direct non-virtual
3827 bases can be calculated by going back to the TYPE. */
3830 offset,
3834 f,
3835 binfo_offset,
3836 offsets,
3837 max_offset,
3841 }
3844 {
3848 /* Iterate through the virtual base classes of TYPE. In G++
3849 3.2, we included virtual bases in the direct base class
3850 loop above, which results in incorrect results; the
3851 correct offsets for virtual bases are only known when
3852 working with the most derived type. */
3856 {
3858 f,
3860 offset,
3862 offsets,
3863 max_offset,
3867 }
3868 else
3869 {
3870 /* We still have to walk the primary base, if it is
3871 virtual. (If it is non-virtual, then it was walked
3872 above.) */
3878 {
3879 r = (walk_subobject_offsets
3884 }
3885 }
3886 }
3888 /* Iterate through the fields of TYPE. */
3893 {
3894 tree field_offset;
3899 f,
3901 offset,
3902 field_offset),
3903 offsets,
3904 max_offset,
3908 }
3909 }
3911 {
3914 tree index;
3916 /* Avoid recursing into objects that are not interesting. */
3919 || !domain
3923 /* Step through each of the elements in the array. */
3927 {
3929 f,
3930 offset,
3931 offsets,
3932 max_offset,
3938 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3939 there's no point in iterating through the remaining
3940 elements of the array. */
3943 }
3944 }
3947 }
3949 /* Record all of the empty subobjects of TYPE (either a type or a
3950 binfo). If IS_DATA_MEMBER is true, then a non-static data member
3951 is being placed at OFFSET; otherwise, it is a base class that is
3952 being placed at OFFSET. */
3954 static void
3956 tree offset,
3957 splay_tree offsets,
3959 {
3960 tree max_offset;
3961 /* If recording subobjects for a non-static data member or a
3962 non-empty base class , we do not need to record offsets beyond
3963 the size of the biggest empty class. Additional data members
3964 will go at the end of the class. Additional base classes will go
3965 either at offset zero (if empty, in which case they cannot
3966 overlap with offsets past the size of the biggest empty class) or
3967 at the end of the class.
3969 However, if we are placing an empty base class, then we must record
3970 all offsets, as either the empty class is at offset zero (where
3971 other empty classes might later be placed) or at the end of the
3972 class (where other objects might then be placed, so other empty
3973 subobjects might later overlap). */
3977 else
3981 }
3983 /* Returns nonzero if any of the empty subobjects of TYPE (located at
3984 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
3985 virtual bases of TYPE are examined. */
3987 static int
3989 tree offset,
3990 splay_tree offsets,
3992 {
3993 splay_tree_node max_node;
3995 /* Get the node in OFFSETS that indicates the maximum offset where
3996 an empty subobject is located. */
3998 /* If there aren't any empty subobjects, then there's no point in
3999 performing this check. */
4005 vbases_p);
4006 }
4008 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4009 non-static data member of the type indicated by RLI. BINFO is the
4010 binfo corresponding to the base subobject, OFFSETS maps offsets to
4011 types already located at those offsets. This function determines
4012 the position of the DECL. */
4014 static void
4016 tree decl,
4017 tree binfo,
4018 splay_tree offsets)
4019 {
4022 tree type;
4025 {
4026 /* For the purposes of determining layout conflicts, we want to
4027 use the class type of BINFO; TREE_TYPE (DECL) will be the
4028 CLASSTYPE_AS_BASE version, which does not contain entries for
4029 zero-sized bases. */
4032 }
4033 else
4034 {
4037 }
4039 /* Try to place the field. It may take more than one try if we have
4040 a hard time placing the field without putting two objects of the
4041 same type at the same address. */
4043 {
4046 /* Place this field. */
4050 /* We have to check to see whether or not there is already
4051 something of the same type at the offset we're about to use.
4052 For example, consider:
4054 struct S {};
4055 struct T : public S { int i; };
4056 struct U : public S, public T {};
4058 Here, we put S at offset zero in U. Then, we can't put T at
4059 offset zero -- its S component would be at the same address
4060 as the S we already allocated. So, we have to skip ahead.
4061 Since all data members, including those whose type is an
4062 empty class, have nonzero size, any overlap can happen only
4063 with a direct or indirect base-class -- it can't happen with
4064 a data member. */
4065 /* In a union, overlap is permitted; all members are placed at
4066 offset zero. */
4071 {
4072 /* Strip off the size allocated to this field. That puts us
4073 at the first place we could have put the field with
4074 proper alignment. */
4077 /* Bump up by the alignment required for the type. */
4078 rli->bitpos
4084 }
4087 {
4088 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4089 the offset wasn't aligned like a pointer when we started to
4090 layout this field, that affects its position. */
4093 {
4096 "alignment of %qD increased in -fabi-version=9 "
4098 else
4101 }
4103 }
4104 else
4105 /* There was no conflict. We're done laying out this field. */
4107 }
4109 /* Now that we know where it will be placed, update its
4110 BINFO_OFFSET. */
4112 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4113 this point because their BINFO_OFFSET is copied from another
4114 hierarchy. Therefore, we may not need to add the entire
4115 OFFSET. */
4121 }
4123 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4125 static int
4127 tree offset,
4129 {
4131 }
4133 /* Layout the empty base BINFO. EOC indicates the byte currently just
4134 past the end of the class, and should be correctly aligned for a
4135 class of the type indicated by BINFO; OFFSETS gives the offsets of
4136 the empty bases allocated so far. T is the most derived
4137 type. Return nonzero iff we added it at the end. */
4139 static bool
4142 {
4143 tree alignment;
4147 /* This routine should only be used for empty classes. */
4152 propagate_binfo_offsets
4156 /* This is an empty base class. We first try to put it at offset
4157 zero. */
4160 offsets,
4162 {
4163 /* That didn't work. Now, we move forward from the next
4164 available spot in the class. */
4168 {
4171 offsets,
4173 /* We finally found a spot where there's no overlap. */
4176 /* There's overlap here, too. Bump along to the next spot. */
4178 }
4179 }
4182 {
4187 }
4190 }
4192 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4193 fields at NEXT_FIELD, and return it. */
4195 static tree
4197 {
4198 /* Create the FIELD_DECL. */
4206 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4208 else
4209 {
4212 }
4218 /* Add the new FIELD_DECL to the list of fields for T. */
4224 }
4226 /* Layout the base given by BINFO in the class indicated by RLI.
4227 *BASE_ALIGN is a running maximum of the alignments of
4228 any base class. OFFSETS gives the location of empty base
4229 subobjects. T is the most derived type. Return nonzero if the new
4230 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4231 *NEXT_FIELD, unless BINFO is for an empty base class.
4233 Returns the location at which the next field should be inserted. */
4238 {
4243 /* This error is now reported in xref_tag, thus giving better
4244 location information. */
4247 /* Place the base class. */
4249 {
4250 tree decl;
4252 /* The containing class is non-empty because it has a non-empty
4253 base class. */
4256 /* Create the FIELD_DECL. */
4259 /* Try to place the field. It may take more than one try if we
4260 have a hard time placing the field without putting two
4261 objects of the same type at the same address. */
4263 }
4264 else
4265 {
4266 tree eoc;
4269 /* On some platforms (ARM), even empty classes will not be
4270 byte-aligned. */
4275 /* A nearly-empty class "has no proper base class that is empty,
4276 not morally virtual, and at an offset other than zero." */
4278 {
4281 /* The check above (used in G++ 3.2) is insufficient because
4282 an empty class placed at offset zero might itself have an
4283 empty base at a nonzero offset. */
4285 empty_base_at_nonzero_offset_p,
4286 size_zero_node,
4291 }
4293 /* We used to not create a FIELD_DECL for empty base classes because of
4294 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4295 be a problem anymore. We need them to handle initialization of C++17
4296 aggregate bases. */
4298 {
4303 }
4305 /* An empty virtual base causes a class to be non-empty
4306 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4307 here because that was already done when the virtual table
4308 pointer was created. */
4309 }
4311 /* Record the offsets of BINFO and its base subobjects. */
4314 offsets,
4318 }
4320 /* Layout all of the non-virtual base classes. Record empty
4321 subobjects in OFFSETS. T is the most derived type. Return nonzero
4322 if the type cannot be nearly empty. The fields created
4323 corresponding to the base classes will be inserted at
4324 *NEXT_FIELD. */
4326 static void
4329 {
4330 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4331 subobjects. */
4336 /* The primary base class is always allocated first. */
4341 /* Now allocate the rest of the bases. */
4343 {
4344 tree base_binfo;
4348 /* The primary base was already allocated above, so we don't
4349 need to allocate it again here. */
4353 /* Virtual bases are added at the end (a primary virtual base
4354 will have already been added). */
4360 }
4361 }
4363 /* Go through the TYPE_FIELDS of T issuing any appropriate
4364 diagnostics, figuring out which methods override which other
4365 methods, and so forth. */
4367 static void
4369 {
4372 {
4378 /* The name of the field is the original field name
4379 Save this in auxiliary field for later overloading. */
4381 {
4385 }
4387 /* All user-provided destructors are non-trivial.
4388 Constructors and assignment ops are handled in
4389 grok_special_member_properties. */
4396 "%<transaction_safe_dynamic%> may only be specified for "
4398 }
4399 }
4401 /* FN is a constructor or destructor. Clone the declaration to create
4402 a specialized in-charge or not-in-charge version, as indicated by
4403 NAME. */
4405 static tree
4407 {
4408 tree parms;
4409 tree clone;
4411 /* Copy the function. */
4413 /* Reset the function name. */
4415 /* Remember where this function came from. */
4417 /* Make it easy to find the CLONE given the FN. */
4421 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4423 {
4430 }
4431 else
4432 {
4433 // Clone constraints.
4437 }
4442 /* There's no pending inline data for this function. */
4446 /* The base-class destructor is not virtual. */
4448 {
4452 }
4458 /* If there was an in-charge parameter, drop it from the function
4459 type. */
4461 {
4462 tree basetype;
4463 tree parmtypes;
4464 tree exceptions;
4469 /* Skip the `this' parameter. */
4471 /* Skip the in-charge parameter. */
4473 /* And the VTT parm, in a complete [cd]tor. */
4478 {
4479 /* If we're omitting inherited parms, that just leaves the VTT. */
4482 }
4486 parmtypes);
4489 exceptions);
4493 }
4495 /* Copy the function parameters. */
4497 /* Remove the in-charge parameter. */
4499 {
4503 }
4504 /* And the VTT parm, in a complete [cd]tor. */
4506 {
4509 else
4510 {
4514 }
4515 }
4517 /* A base constructor inheriting from a virtual base doesn't get the
4518 arguments. */
4523 {
4526 }
4528 /* Create the RTL for this function. */
4533 }
4535 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4536 not invoke this function directly.
4538 For a non-thunk function, returns the address of the slot for storing
4539 the function it is a clone of. Otherwise returns NULL_TREE.
4541 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4542 cloned_function is unset. This is to support the separate
4543 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4544 on a template makes sense, but not the former. */
4546 tree *
4548 {
4556 {
4557 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4560 else
4561 #endif
4563 }
4568 else
4570 }
4572 /* Produce declarations for all appropriate clones of FN. If
4573 UPDATE_METHODS is true, the clones are added to the
4574 CLASSTYPE_MEMBER_VEC. */
4576 void
4578 {
4579 tree clone;
4581 /* Avoid inappropriate cloning. */
4587 {
4588 /* For each constructor, we need two variants: an in-charge version
4589 and a not-in-charge version. */
4596 }
4597 else
4598 {
4601 /* For each destructor, we need three variants: an in-charge
4602 version, a not-in-charge version, and an in-charge deleting
4603 version. We clone the deleting version first because that
4604 means it will go second on the TYPE_FIELDS list -- and that
4605 corresponds to the correct layout order in the virtual
4606 function table.
4608 For a non-virtual destructor, we do not build a deleting
4609 destructor. */
4611 {
4615 }
4622 }
4624 /* Note that this is an abstract function that is never emitted. */
4626 }
4628 /* DECL is an in charge constructor, which is being defined. This will
4629 have had an in class declaration, from whence clones were
4630 declared. An out-of-class definition can specify additional default
4631 arguments. As it is the clones that are involved in overload
4632 resolution, we must propagate the information from the DECL to its
4633 clones. */
4635 void
4637 {
4638 tree clone;
4642 {
4649 /* Skip the 'this' parameter. */
4665 {
4667 {
4671 }
4677 {
4678 /* A default parameter has been added. Adjust the
4679 clone's parameters. */
4683 tree type;
4688 {
4691 clone_parms);
4693 }
4696 clone_parms);
4705 }
4706 }
4708 }
4709 }
4711 /* For each of the constructors and destructors in T, create an
4712 in-charge and not-in-charge variant. */
4714 static void
4716 {
4717 /* While constructors can be via a using declaration, at this point
4718 we no longer need to know that. */
4724 }
4726 /* Deduce noexcept for a destructor DTOR. */
4728 void
4730 {
4733 noexcept_deferred_spec);
4734 }
4736 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4737 of TYPE for virtual functions which FNDECL overrides. Return a
4738 mask of the tm attributes found therein. */
4740 static int
4742 {
4744 tree base_binfo;
4748 {
4756 {
4760 else
4763 }
4764 else
4766 }
4769 }
4771 /* Subroutine of set_method_tm_attributes. Handle the checks and
4772 inheritance for one virtual method FNDECL. */
4774 static void
4776 {
4777 tree tm_attr;
4782 /* If FNDECL doesn't actually override anything (i.e. T is the
4783 class that first declares FNDECL virtual), then we're done. */
4790 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4791 tm_pure must match exactly, otherwise no weakening of
4792 tm_safe > tm_callable > nothing. */
4793 /* ??? The tm_pure attribute didn't make the transition to the
4794 multivendor language spec. */
4796 {
4798 {
4801 }
4802 }
4803 /* If the overridden function is tm_pure, then FNDECL must be. */
4806 /* Look for base class combinations that cannot be satisfied. */
4808 {
4814 }
4815 /* If FNDECL did not declare an attribute, then inherit the most
4816 restrictive one. */
4818 {
4820 }
4821 /* Otherwise validate that we're not weaker than a function
4822 that is being overridden. */
4823 else
4824 {
4828 }
4831 err_override:
4835 }
4837 /* For each of the methods in T, propagate a class-level tm attribute. */
4839 static void
4841 {
4844 /* Don't bother collecting tm attributes if transactional memory
4845 support is not enabled. */
4849 /* Process virtual methods first, as they inherit directly from the
4850 base virtual function and also require validation of new attributes. */
4852 {
4853 tree vchain;
4856 {
4861 }
4862 }
4864 /* If the class doesn't have an attribute, nothing more to do. */
4869 /* Any method that does not yet have a tm attribute inherits
4870 the one from the class. */
4875 }
4877 /* Returns true if FN is a default constructor. */
4879 bool
4881 {
4884 }
4886 /* Returns true iff class T has a user-defined constructor that can be called
4887 with more than zero arguments. */
4889 bool
4891 {
4896 {
4903 }
4906 }
4908 /* Returns the defaulted constructor if T has one. Otherwise, returns
4909 NULL_TREE. */
4911 tree
4913 {
4918 {
4924 }
4927 }
4929 /* Returns true iff FN is a user-provided function, i.e. user-declared
4930 and not defaulted at its first declaration. */
4932 bool
4934 {
4937 else
4941 }
4943 /* Returns true iff class T has a user-provided constructor. */
4945 bool
4947 {
4959 }
4961 /* Returns true iff class T has a user-provided or explicit constructor. */
4963 bool
4965 {
4973 {
4977 }
4980 }
4982 /* Returns true iff class T has a non-user-provided (i.e. implicitly
4983 declared or explicitly defaulted in the class body) default
4984 constructor. */
4986 bool
4988 {
4995 {
5001 }
5004 }
5006 /* TYPE is being used as a virtual base, and has a non-trivial move
5007 assignment. Return true if this is due to there being a user-provided
5008 move assignment in TYPE or one of its subobjects; if there isn't, then
5009 multiple move assignment can't cause any harm. */
5011 bool
5013 {
5014 /* Does the type itself have a user-provided move assignment operator? */
5022 /* Do any of its bases? */
5024 tree base_binfo;
5029 /* Or non-static data members? */
5031 {
5036 }
5038 /* Seems not. */
5040 }
5042 /* If default-initialization leaves part of TYPE uninitialized, returns
5043 a DECL for the field or TYPE itself (DR 253). */
5045 tree
5047 {
5058 {
5062 }
5067 {
5071 }
5074 }
5076 /* Returns true iff for class T, a trivial synthesized default constructor
5077 would be constexpr. */
5079 bool
5081 {
5082 /* A defaulted trivial default constructor is constexpr
5083 if there is nothing to initialize. */
5086 }
5088 /* Returns true iff class T has a constexpr default constructor. */
5090 bool
5092 {
5093 tree fns;
5096 {
5097 /* The caller should have stripped an enclosing array. */
5100 }
5102 {
5105 /* Non-trivial, we need to check subobject constructors. */
5107 }
5110 }
5112 /* Returns true iff class T has a constexpr default constructor or has an
5113 implicitly declared default constructor that we can't tell if it's constexpr
5114 without forcing a lazy declaration (which might cause undesired
5115 instantiations). */
5117 bool
5119 {
5122 /* Assume it's constexpr. */
5125 }
5127 /* Returns true iff class TYPE has a virtual destructor. */
5129 bool
5131 {
5132 tree dtor;
5140 }
5142 /* Returns true iff T, a class, has a move-assignment or
5143 move-constructor. Does not lazily declare either.
5144 If USER_P is false, any move function will do. If it is true, the
5145 move function must be user-declared.
5147 Note that user-declared here is different from "user-provided",
5148 which doesn't include functions that are defaulted in the
5149 class. */
5151 bool
5153 {
5171 }
5173 /* Nonzero if we need to build up a constructor call when initializing an
5174 object of this class, either because it has a user-declared constructor
5175 or because it doesn't have a default constructor (so we need to give an
5176 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5177 what you care about is whether or not an object can be produced by a
5178 constructor (e.g. so we don't set TREE_READONLY on const variables of
5179 such type); use this function when what you care about is whether or not
5180 to try to call a constructor to create an object. The latter case is
5181 the former plus some cases of constructors that cannot be called. */
5183 bool
5185 {
5186 tree inner;
5196 /* A user-declared constructor might be private, and a constructor might
5197 be trivial but deleted. */
5200 {
5205 }
5207 }
5209 /* Like type_build_ctor_call, but for destructors. */
5211 bool
5213 {
5214 tree inner;
5223 /* A user-declared destructor might be private, and a destructor might
5224 be trivial but deleted. */
5227 {
5232 }
5234 }
5236 /* Remove all zero-width bit-fields from T. */
5238 static void
5240 {
5245 {
5248 /* We should not be confused by the fact that grokbitfield
5249 temporarily sets the width of the bit field into
5250 DECL_BIT_FIELD_REPRESENTATIVE (*fieldsp).
5251 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5252 to that width. */
5256 else
5258 }
5259 }
5261 /* Returns TRUE iff we need a cookie when dynamically allocating an
5262 array whose elements have the indicated class TYPE. */
5264 static bool
5266 {
5267 tree fns;
5272 /* If there's a non-trivial destructor, we need a cookie. In order
5273 to iterate through the array calling the destructor for each
5274 element, we'll have to know how many elements there are. */
5278 /* If the usual deallocation function is a two-argument whose second
5279 argument is of type `size_t', then we have to pass the size of
5280 the array to the deallocation function, so we will need to store
5281 a cookie. */
5285 /* If there are no `operator []' members, or the lookup is
5286 ambiguous, then we don't need a cookie. */
5289 /* Loop through all of the functions. */
5291 {
5294 /* See if this function is a one-argument delete function. If
5295 it is, then it will be the usual deallocation function. */
5299 /* Do not consider this function if its second argument is an
5300 ellipsis. */
5303 /* Otherwise, if we have a two-argument function and the second
5304 argument is `size_t', it will be the usual deallocation
5305 function -- unless there is one-argument function, too. */
5309 }
5312 }
5314 /* Finish computing the `literal type' property of class type T.
5316 At this point, we have already processed base classes and
5317 non-static data members. We need to check whether the copy
5318 constructor is trivial, the destructor is trivial, and there
5319 is a trivial default constructor or at least one constexpr
5320 constructor other than the copy constructor. */
5322 static void
5324 {
5325 tree fn;
5337 /* C++14 DR 1684 removed this restriction. */
5345 {
5349 "enclosing class of %<constexpr%> non-static member "
5352 }
5353 }
5355 /* T is a non-literal type used in a context which requires a constant
5356 expression. Explain why it isn't literal. */
5358 void
5360 {
5370 /* Already explained. */
5376 " %qT is a closure type, which is only literal in "
5384 {
5386 " %q+T is not an aggregate, does not have a trivial "
5387 "default constructor, and has no %<constexpr%> constructor that "
5390 /* Note that we can't simply call locate_ctor because when the
5391 constructor is deleted it just returns NULL_TREE. */
5393 {
5400 {
5403 else
5406 }
5407 }
5408 }
5409 else
5410 {
5414 {
5417 {
5423 }
5424 }
5426 {
5427 tree ftype;
5432 {
5435 field);
5438 }
5442 }
5443 }
5444 }
5446 /* Check the validity of the bases and members declared in T. Add any
5447 implicitly-generated functions (like copy-constructors and
5448 assignment operators). Compute various flag bits (like
5449 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5450 level: i.e., independently of the ABI in use. */
5452 static void
5454 {
5455 /* Nonzero if the implicitly generated copy constructor should take
5456 a non-const reference argument. */
5458 /* Nonzero if the implicitly generated assignment operator
5459 should take a non-const reference argument. */
5461 tree access_decls;
5464 tree fn;
5466 /* By default, we use const reference arguments and generate default
5467 constructors. */
5471 /* Check all the base-classes and set FMEM members to point to arrays
5472 of potential interest. */
5475 /* Deduce noexcept on destructor. This needs to happen after we've set
5476 triviality flags appropriately for our bases. */
5481 /* Check all the method declarations. */
5484 /* Save the initial values of these flags which only indicate whether
5485 or not the class has user-provided functions. As we analyze the
5486 bases and members we can set these flags for other reasons. */
5490 /* Check all the data member declarations. We cannot call
5491 check_field_decls until we have called check_bases check_methods,
5492 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5493 being set appropriately. */
5498 /* A nearly-empty class has to be vptr-containing; a nearly empty
5499 class contains just a vptr. */
5503 /* Do some bookkeeping that will guide the generation of implicitly
5504 declared member functions. */
5507 /* We need to call a constructor for this class if it has a
5508 user-provided constructor, or if the default constructor is going
5509 to initialize the vptr. (This is not an if-and-only-if;
5510 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5511 themselves need constructing.) */
5514 /* [dcl.init.aggr]
5516 An aggregate is an array or a class with no user-provided
5517 constructors ... and no virtual functions.
5519 Again, other conditions for being an aggregate are checked
5520 elsewhere. */
5524 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5525 retain the old definition internally for ABI reasons. */
5534 /* If the only explicitly declared default constructor is user-provided,
5535 set TYPE_HAS_COMPLEX_DFLT. */
5541 /* Warn if a public base of a polymorphic type has an accessible
5542 non-virtual destructor. It is only now that we know the class is
5543 polymorphic. Although a polymorphic base will have a already
5544 been diagnosed during its definition, we warn on use too. */
5546 {
5549 tree base_binfo;
5553 {
5561 basetype);
5562 }
5563 }
5565 /* If the class has no user-declared constructor, but does have
5566 non-static const or reference data members that can never be
5567 initialized, issue a warning. */
5569 /* Classes with user-declared constructors are presumed to
5570 initialize these members. */
5572 /* Aggregates can be initialized with brace-enclosed
5573 initializers. */
5575 {
5576 tree field;
5579 {
5580 tree type;
5597 }
5598 }
5600 /* Synthesize any needed methods. */
5602 cant_have_const_ctor,
5603 no_const_asn_ref);
5605 /* Check defaulted declarations here so we have cant_have_const_ctor
5606 and don't need to worry about clones. */
5611 {
5614 {
5615 bool imp_const_p
5621 /* If the function is defaulted outside the class, we just
5622 give the synthesis error. */
5625 }
5627 }
5630 {
5631 /* "This class type is not an aggregate." */
5633 }
5635 /* Compute the 'literal type' property before we
5636 do anything with non-static member functions. */
5639 /* Create the in-charge and not-in-charge variants of constructors
5640 and destructors. */
5643 /* Process the using-declarations. */
5647 /* Figure out whether or not we will need a cookie when dynamically
5648 allocating an array of this type. */
5651 }
5653 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5654 accordingly. If a new vfield was created (because T doesn't have a
5655 primary base class), then the newly created field is returned. It
5656 is not added to the TYPE_FIELDS list; it is the caller's
5657 responsibility to do that. Accumulate declared virtual functions
5658 on VIRTUALS_P. */
5660 static tree
5662 {
5663 tree fn;
5665 /* Collect the virtual functions declared in T. */
5670 {
5679 }
5681 /* If we couldn't find an appropriate base class, create a new field
5682 here. Even if there weren't any new virtual functions, we might need a
5683 new virtual function table if we're supposed to include vptrs in
5684 all classes that need them. */
5686 {
5687 /* We build this decl with vtbl_ptr_type_node, which is a
5688 `vtable_entry_type*'. It might seem more precise to use
5689 `vtable_entry_type (*)[N]' where N is the number of virtual
5690 functions. However, that would require the vtable pointer in
5691 base classes to have a different type than the vtable pointer
5692 in derived classes. We could make that happen, but that
5693 still wouldn't solve all the problems. In particular, the
5694 type-based alias analysis code would decide that assignments
5695 to the base class vtable pointer can't alias assignments to
5696 the derived class vtable pointer, since they have different
5697 types. Thus, in a derived class destructor, where the base
5698 class constructor was inlined, we could generate bad code for
5699 setting up the vtable pointer.
5701 Therefore, we use one type for all vtable pointers. We still
5702 use a type-correct type; it's just doesn't indicate the array
5703 bounds. That's better than using `void*' or some such; it's
5704 cleaner, and it let's the alias analysis code know that these
5705 stores cannot alias stores to void*! */
5706 tree field;
5719 /* This class is non-empty. */
5723 }
5726 }
5728 /* Add OFFSET to all base types of BINFO which is a base in the
5729 hierarchy dominated by T.
5731 OFFSET, which is a type offset, is number of bytes. */
5733 static void
5735 {
5737 tree primary_binfo;
5738 tree base_binfo;
5740 /* Update BINFO's offset. */
5745 offset));
5747 /* Find the primary base class. */
5753 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5754 downwards. */
5756 {
5757 /* Don't do the primary base twice. */
5765 }
5766 }
5768 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5769 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5770 empty subobjects of T. */
5772 static void
5774 {
5775 tree vbase;
5782 /* Find the last field. The artificial fields created for virtual
5783 bases will go after the last extant field to date. */
5788 /* Go through the virtual bases, allocating space for each virtual
5789 base that is not already a primary base class. These are
5790 allocated in inheritance graph order. */
5792 {
5797 {
5798 /* This virtual base is not a primary base of any class in the
5799 hierarchy, so we have to add space for it. */
5802 }
5803 }
5804 }
5806 /* Returns the offset of the byte just past the end of the base class
5807 BINFO. */
5809 static tree
5811 {
5812 tree size;
5817 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5818 allocate some space for it. It cannot have virtual bases, so
5819 TYPE_SIZE_UNIT is fine. */
5821 else
5825 }
5827 /* Returns the offset of the byte just past the end of the base class
5828 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
5829 only non-virtual bases are included. */
5831 static tree
5833 {
5836 tree binfo;
5837 tree base_binfo;
5838 tree offset;
5843 {
5853 }
5858 {
5862 }
5865 }
5867 /* Warn about bases of T that are inaccessible because they are
5868 ambiguous. For example:
5870 struct S {};
5871 struct T : public S {};
5872 struct U : public S, public T {};
5874 Here, `(S*) new U' is not allowed because there are two `S'
5875 subobjects of U. */
5877 static void
5879 {
5882 tree basetype;
5883 tree binfo;
5884 tree base_binfo;
5886 /* If there are no repeated bases, nothing can be ambiguous. */
5890 /* Check direct bases. */
5893 {
5899 }
5901 /* Check for ambiguous virtual bases. */
5905 {
5911 }
5912 }
5914 /* Compare two INTEGER_CSTs K1 and K2. */
5916 static int
5918 {
5920 }
5922 /* Increase the size indicated in RLI to account for empty classes
5923 that are "off the end" of the class. */
5925 static void
5927 {
5928 tree eoc;
5929 tree rli_size;
5931 /* It might be the case that we grew the class to allocate a
5932 zero-sized base class. That won't be reflected in RLI, yet,
5933 because we are willing to overlay multiple bases at the same
5934 offset. However, now we need to make sure that RLI is big enough
5935 to reflect the entire class. */
5940 {
5941 /* The size should have been rounded to a whole byte. */
5944 rli->bitpos
5953 }
5954 }
5956 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
5957 BINFO_OFFSETs for all of the base-classes. Position the vtable
5958 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
5960 static void
5962 {
5963 tree non_static_data_members;
5964 tree field;
5965 tree vptr;
5966 record_layout_info rli;
5967 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
5968 types that appear at that offset. */
5969 splay_tree empty_base_offsets;
5970 /* True if the last field laid out was a bit-field. */
5972 /* The location at which the next field should be inserted. */
5975 /* Keep track of the first non-static data member. */
5978 /* Start laying out the record. */
5981 /* Mark all the primary bases in the hierarchy. */
5984 /* Create a pointer to our virtual function table. */
5987 /* The vptr is always the first thing in the class. */
5989 {
5994 }
5995 else
5998 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6003 /* Layout the non-static data members. */
6005 {
6006 tree type;
6007 tree padding;
6009 /* We still pass things that aren't non-static data members to
6010 the back end, in case it wants to do something with them. */
6012 {
6014 /* If the static data member has incomplete type, keep track
6015 of it so that it can be completed later. (The handling
6016 of pending statics in finish_record_layout is
6017 insufficient; consider:
6019 struct S1;
6020 struct S2 { static S1 s1; };
6022 At this point, finish_record_layout will be called, but
6023 S1 is still incomplete.) */
6025 {
6027 /* The visibility of static data members is determined
6028 at their point of declaration, not their point of
6029 definition. */
6031 }
6033 }
6041 /* If this field is a bit-field whose width is greater than its
6042 type, then there are some special rules for allocating
6043 it. */
6046 {
6048 /* We must allocate the bits as if suitably aligned for the
6049 longest integer type that fits in this many bits. Then,
6050 we are supposed to use the left over bits as additional
6051 padding. */
6053 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6061 {
6063 /* Too big, so our current guess is what we want. */
6065 /* Not bigger than limit, ok */
6067 }
6069 /* Figure out how much additional padding is required. */
6071 /* In a union, the padding field must have the full width
6072 of the bit-field; all fields start at offset zero. */
6074 else
6081 /* An unnamed bitfield does not normally affect the
6082 alignment of the containing class on a target where
6083 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6084 make any exceptions for unnamed bitfields when the
6085 bitfields are longer than their types. Therefore, we
6086 temporarily give the field a name. */
6088 {
6091 }
6097 empty_base_offsets);
6100 /* Now that layout has been performed, set the size of the
6101 field to the size of its declared type; the rest of the
6102 field is effectively invisible. */
6104 /* We must also reset the DECL_MODE of the field. */
6106 }
6107 else
6109 empty_base_offsets);
6111 /* Remember the location of any empty classes in FIELD. */
6114 empty_base_offsets,
6117 /* If a bit-field does not immediately follow another bit-field,
6118 and yet it starts in the middle of a byte, we have failed to
6119 comply with the ABI. */
6122 /* The TREE_NO_WARNING flag gets set by Objective-C when
6123 laying out an Objective-C class. The ObjC ABI differs
6124 from the C++ ABI, and so we do not want a warning
6125 here. */
6127 && !last_field_was_bitfield
6130 bitsize_unit_node)))
6132 "offset of %qD is not ABI-compliant and may "
6135 /* The middle end uses the type of expressions to determine the
6136 possible range of expression values. In order to optimize
6137 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6138 must be made aware of the width of "i", via its type.
6140 Because C++ does not have integer types of arbitrary width,
6141 we must (for the purposes of the front end) convert from the
6142 type assigned here to the declared type of the bitfield
6143 whenever a bitfield expression is used as an rvalue.
6144 Similarly, when assigning a value to a bitfield, the value
6145 must be converted to the type given the bitfield here. */
6147 {
6152 {
6159 }
6160 }
6162 /* If we needed additional padding after this field, add it
6163 now. */
6165 {
6166 tree padding_field;
6169 FIELD_DECL,
6170 NULL_TREE,
6171 char_type_node);
6179 NULL_TREE,
6180 empty_base_offsets);
6181 }
6184 }
6187 {
6188 /* Make sure that we are on a byte boundary so that the size of
6189 the class without virtual bases will always be a round number
6190 of bytes. */
6193 }
6195 /* Delete all zero-width bit-fields from the list of fields. Now
6196 that the type is laid out they are no longer important. */
6200 {
6201 /* T needs a different layout as a base (eliding virtual bases
6202 or whatever). Create that version. */
6205 /* If the ABI version is not at least two, and the last
6206 field was a bit-field, RLI may not be on a byte
6207 boundary. In particular, rli_size_unit_so_far might
6208 indicate the last complete byte, while rli_size_so_far
6209 indicates the total number of bits used. Therefore,
6210 rli_size_so_far, rather than rli_size_unit_so_far, is
6211 used to compute TYPE_SIZE_UNIT. */
6219 eoc);
6229 /* Copy the non-static data members of T. This will include its
6230 direct non-virtual bases & vtable. */
6234 {
6238 }
6241 /* We use the base type for trivial assignments, and hence it
6242 needs a mode. */
6247 /* Record the base version of the type. */
6249 }
6250 else
6253 /* Every empty class contains an empty class. */
6257 /* Set the TYPE_DECL for this type to contain the right
6258 value for DECL_OFFSET, so that we can use it as part
6259 of a COMPONENT_REF for multiple inheritance. */
6262 /* Now fix up any virtual base class types that we left lying
6263 around. We must get these done before we try to lay out the
6264 virtual function table. As a side-effect, this will remove the
6265 base subobject fields. */
6268 /* Make sure that empty classes are reflected in RLI at this
6269 point. */
6272 /* Make sure not to create any structures with zero size. */
6278 /* If this is a non-POD, declaring it packed makes a difference to how it
6279 can be used as a field; don't let finalize_record_size undo it. */
6283 /* Let the back end lay out the type. */
6292 /* Warn about bases that can't be talked about due to ambiguity. */
6295 /* Now that we're done with layout, give the base fields the real types. */
6300 /* Clean up. */
6307 }
6309 /* Determine the "key method" for the class type indicated by TYPE,
6310 and set CLASSTYPE_KEY_METHOD accordingly. */
6312 void
6314 {
6315 tree method;
6322 /* The key method is the first non-pure virtual function that is not
6323 inline at the point of class definition. On some targets the
6324 key function may not be inline; those targets should not call
6325 this function until the end of the translation unit. */
6331 {
6334 }
6337 }
6339 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6340 class data member of non-zero size, otherwise false. */
6344 {
6352 {
6356 }
6359 }
6361 /* Used by find_flexarrays and related functions. */
6363 struct flexmems_t
6364 {
6365 /* The first flexible array member or non-zero array member found
6366 in the order of layout. */
6367 tree array;
6368 /* First non-static non-empty data member in the class or its bases. */
6369 tree first;
6370 /* The first non-static non-empty data member following either
6371 the flexible array member, if found, or the zero-length array member
6372 otherwise. AFTER[1] refers to the first such data member of a union
6373 of which the struct containing the flexible array member or zero-length
6374 array is a member, or NULL when no such union exists. This element is
6375 only used during searching, not for diagnosing problems. AFTER[0]
6376 refers to the first such data member that is not a member of such
6377 a union. */
6380 /* Refers to a struct (not union) in which the struct of which the flexible
6381 array is member is defined. Used to diagnose strictly (according to C)
6382 invalid uses of the latter structs. */
6383 tree enclosing;
6384 };
6386 /* Find either the first flexible array member or the first zero-length
6387 array, in that order of preference, among members of class T (but not
6388 its base classes), and set members of FMEM accordingly.
6389 BASE_P is true if T is a base class of another class.
6390 PUN is set to the outermost union in which the flexible array member
6391 (or zero-length array) is defined if one such union exists, otherwise
6392 to NULL.
6393 Similarly, PSTR is set to a data member of the outermost struct of
6394 which the flexible array is a member if one such struct exists,
6395 otherwise to NULL. */
6397 static void
6401 {
6402 /* Set the "pointer" to the outermost enclosing union if not set
6403 yet and maintain it for the remainder of the recursion. */
6408 {
6412 /* Is FLD a typedef for an anonymous struct? */
6414 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6415 handled elsewhere so that errors like the following are detected
6416 as well:
6417 typedef struct { int i, a[], j; } S; // bug c++/72753
6418 S s [2]; // bug c++/68489
6419 */
6424 {
6425 /* Check the nested unnamed type referenced via a typedef
6426 independently of FMEM (since it's not a data member of
6427 the enclosing class). */
6430 }
6432 /* Skip anything that's GCC-generated or not a (non-static) data
6433 member. */
6437 /* Type of the member. */
6442 /* Determine the type of the array element or object referenced
6443 by the member so that it can be checked for flexible array
6444 members if it hasn't been yet. */
6452 {
6454 {
6455 /* Once the member after the flexible array has been found
6456 we're done. */
6459 }
6462 {
6463 /* Descend into the non-static member struct or union and try
6464 to find a flexible array member or zero-length array among
6465 its members. This is only necessary for anonymous types
6466 and types in whose context the current type T has not been
6467 defined (the latter must not be checked again because they
6468 are already in the process of being checked by one of the
6469 recursive calls). */
6474 /* If this member isn't anonymous and a prior non-flexible array
6475 member has been seen in one of the enclosing structs, clear
6476 the FIRST member since it doesn't contribute to the flexible
6477 array struct's members. */
6488 {
6489 /* Restore the FIRST member reset above if no flexible
6490 array member has been found in this member's struct. */
6492 }
6494 /* If the member struct contains the first flexible array
6495 member, or if this member is a base class, continue to
6496 the next member and avoid setting the FMEM->NEXT pointer
6497 to point to it. */
6500 }
6501 }
6504 {
6505 /* Remember the first non-static data member. */
6509 /* Remember the first non-static data member after the flexible
6510 array member, if one has been found, or the zero-length array
6511 if it has been found. */
6514 }
6516 /* Skip non-arrays. */
6520 /* Determine the upper bound of the array if it has one. */
6522 {
6524 {
6525 /* Make a record of the zero-length array if either one
6526 such field or a flexible array member has been seen to
6527 handle the pathological and unlikely case of multiple
6528 such members. */
6531 }
6533 {
6534 /* Remember the first zero-length array unless a flexible array
6535 member has already been seen. */
6538 }
6539 }
6540 else
6541 {
6542 /* Flexible array members have no upper bound. */
6544 {
6546 {
6547 /* Replace the zero-length array if it's been stored and
6548 reset the after pointer. */
6552 }
6554 /* Make a record of another flexible array member. */
6556 }
6557 else
6558 {
6561 }
6562 }
6563 }
6564 }
6566 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6567 a flexible array member (or the zero-length array extension). */
6569 static void
6571 {
6583 }
6585 /* Issue diagnostics for invalid flexible array members or zero-length
6586 arrays that are not the last elements of the containing class or its
6587 base classes or that are its sole members. */
6589 static void
6591 {
6596 {
6599 }
6601 /* Has a diagnostic been issued? */
6607 {
6614 {
6618 {
6621 }
6622 }
6623 }
6624 else
6625 {
6632 {
6638 /* In the unlikely event that the member following the flexible
6639 array member is declared in a different class, or the member
6640 overlaps another member of a common union, point to it.
6641 Otherwise it should be obvious. */
6645 {
6650 }
6651 }
6652 }
6656 }
6659 /* Recursively check to make sure that any flexible array or zero-length
6660 array members of class T or its bases are valid (i.e., not the sole
6661 non-static data member of T and, if one exists, that it is the last
6662 non-static data member of T and its base classes. FMEM is expected
6663 to be initially null and is used internally by recursive calls to
6664 the function. Issue the appropriate diagnostics for the array member
6665 that fails the checks. */
6667 static void
6670 {
6671 /* Initialize the result of a search for flexible array and zero-length
6672 array members. Avoid doing any work if the most interesting FMEM data
6673 have already been populated. */
6682 /* Recursively check the primary base class first. */
6684 {
6687 }
6689 /* Recursively check the base classes. */
6692 {
6695 /* The primary base class was already checked above. */
6699 /* Virtual base classes are at the end. */
6703 /* Check the base class. */
6705 }
6708 {
6709 /* Check virtual base classes only once per derived class.
6710 I.e., this check is not performed recursively for base
6711 classes. */
6713 tree base_binfo;
6717 {
6718 /* Check the virtual base class. */
6722 }
6723 }
6725 /* Is the type unnamed (and therefore a member of it potentially
6726 an anonymous struct or union)? */
6729 /* Search the members of the current (possibly derived) class, skipping
6730 unnamed structs and unions since those could be anonymous. */
6735 {
6736 /* Issue diagnostics for invalid flexible and zero-length array
6737 members found in base classes or among the members of the current
6738 class. Ignore anonymous structs and unions whose members are
6739 considered to be members of the enclosing class and thus will
6740 be diagnosed when checking it. */
6742 }
6743 }
6745 /* Perform processing required when the definition of T (a class type)
6746 is complete. Diagnose invalid definitions of flexible array members
6747 and zero-size arrays. */
6749 void
6751 {
6752 tree x;
6753 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6757 {
6762 }
6764 /* If this type was previously laid out as a forward reference,
6765 make sure we lay it out again. */
6769 /* Make assumptions about the class; we'll reset the flags if
6770 necessary. */
6776 /* Do end-of-class semantic processing: checking the validity of the
6777 bases and members and add implicitly generated methods. */
6780 /* Find the key method. */
6782 {
6783 /* The Itanium C++ ABI permits the key method to be chosen when
6784 the class is defined -- even though the key method so
6785 selected may later turn out to be an inline function. On
6786 some systems (such as ARM Symbian OS) the key method cannot
6787 be determined until the end of the translation unit. On such
6788 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6789 will cause the class to be added to KEYED_CLASSES. Then, in
6790 finish_file we will determine the key method. */
6794 /* If a polymorphic class has no key method, we may emit the vtable
6795 in every translation unit where the class definition appears. If
6796 we're devirtualizing, we can look into the vtable even if we
6797 aren't emitting it. */
6800 }
6802 /* Layout the class itself. */
6804 /* COMPLETE_TYPE_P is now true. */
6808 /* With the layout complete, check for flexible array members and
6809 zero-length arrays that might overlap other members in the final
6810 layout. */
6815 /* If necessary, create the primary vtable for this class. */
6817 {
6818 /* We must enter these virtuals into the table. */
6822 /* Here we know enough to change the type of our virtual
6823 function table, but we will wait until later this function. */
6826 /* If we're warning about ABI tags, check the types of the new
6827 virtual functions. */
6831 }
6834 {
6836 tree fn;
6843 /* Add entries for virtual functions introduced by this class. */
6847 /* Set DECL_VINDEX for all functions declared in this class. */
6849 fn;
6851 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6853 {
6857 /* A thunk. We should never be calling this entry directly
6858 from this vtable -- we'd use the entry for the non
6859 thunk base function. */
6863 }
6864 }
6872 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
6873 for any static member objects of the type we're working on. */
6882 /* Complain if one of the field types requires lower visibility. */
6885 /* Make the rtl for any new vtables we have created, and unmark
6886 the base types we marked. */
6889 /* Build the VTT for T. */
6896 "%q#T has virtual functions and accessible"
6904 /* Class layout, assignment of virtual table slots, etc., is now
6905 complete. Give the back end a chance to tweak the visibility of
6906 the class or perform any other required target modifications. */
6916 /* Finish debugging output for this type. */
6920 {
6923 {
6926 }
6928 {
6931 else
6932 {
6935 }
6937 }
6939 {
6941 "the type of the first field has a different ABI from the "
6944 }
6945 }
6946 }
6948 /* When T was built up, the member declarations were added in reverse
6949 order. Rearrange them to declaration order. */
6951 void
6953 {
6954 tree next;
6955 tree prev;
6956 tree x;
6958 /* The following lists are all in reverse order. Put them in
6959 declaration order now. */
6962 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
6963 order, so we can't just use nreverse. Due to stat_hack
6964 chicanery in finish_member_declaration. */
6969 {
6973 }
6976 {
6979 }
6980 }
6982 tree
6984 {
6987 /* Now that we've got all the field declarations, reverse everything
6988 as necessary. */
6994 /* Nadger the current location so that diagnostics point to the start of
6995 the struct, not the end. */
6999 {
7000 tree x;
7002 /* We need to add the target functions of USING_DECLS, so that
7003 they can be found when the using declaration is not
7004 instantiated yet. */
7007 {
7012 }
7018 /* COMPLETE_TYPE_P is now true. */
7022 /* We need to emit an error message if this type was used as a parameter
7023 and it is an abstract type, even if it is a template. We construct
7024 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7025 account and we call complete_vars with this type, which will check
7026 the PARM_DECLS. Note that while the type is being defined,
7027 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7028 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7035 /* Remember current #pragma pack value. */
7038 /* Fix up any variants we've already built. */
7040 {
7044 }
7045 }
7046 else
7048 /* COMPLETE_TYPE_P is now true. */
7053 {
7054 /* People keep complaining that the compiler crashes on an invalid
7055 definition of initializer_list, so I guess we should explicitly
7056 reject it. What the compiler internals care about is that it's a
7057 template and has a pointer field followed by size_type field. */
7060 {
7063 {
7067 }
7068 }
7072 }
7080 else
7084 /* Lambdas are defined by the LAMBDA_EXPR. */
7089 }
7090 \f
7091 /* Hash table to avoid endless recursion when handling references. */
7094 /* Return the dynamic type of INSTANCE, if known.
7095 Used to determine whether the virtual function table is needed
7096 or not.
7098 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7099 of our knowledge of its type. *NONNULL should be initialized
7100 before this function is called. */
7102 static tree
7104 {
7105 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7108 {
7112 else
7116 /* This is a call to a constructor, hence it's never zero. */
7119 {
7123 }
7127 /* This is a call to a constructor, hence it's never zero. */
7129 {
7133 }
7142 /* Propagate nonnull. */
7147 CASE_CONVERT:
7153 {
7154 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7155 with a real object -- given &p->f, p can still be null. */
7157 /* ??? Probably should check DECL_WEAK here. */
7160 }
7164 /* If this component is really a base class reference, then the field
7165 itself isn't definitive. */
7174 {
7178 }
7179 /* fall through. */
7184 {
7188 }
7190 {
7194 /* if we're in a ctor or dtor, we know our type. If
7195 current_class_ptr is set but we aren't in a function, we're in
7196 an NSDMI (and therefore a constructor). */
7201 {
7205 }
7206 }
7208 {
7209 /* We only need one hash table because it is always left empty. */
7211 fixed_type_or_null_ref_ht
7214 /* Reference variables should be references to objects. */
7218 /* Enter the INSTANCE in a table to prevent recursion; a
7219 variable's initializer may refer to the variable
7220 itself. */
7225 {
7226 tree type;
7235 }
7236 }
7241 }
7242 #undef RECUR
7243 }
7245 /* Return nonzero if the dynamic type of INSTANCE is known, and
7246 equivalent to the static type. We also handle the case where
7247 INSTANCE is really a pointer. Return negative if this is a
7248 ctor/dtor. There the dynamic type is known, but this might not be
7249 the most derived base of the original object, and hence virtual
7250 bases may not be laid out according to this type.
7252 Used to determine whether the virtual function table is needed
7253 or not.
7255 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7256 of our knowledge of its type. *NONNULL should be initialized
7257 before this function is called. */
7259 int
7261 {
7264 tree fixed;
7266 /* processing_template_decl can be false in a template if we're in
7267 instantiate_non_dependent_expr, but we still want to suppress
7268 this check. */
7270 {
7271 /* In a template we only care about the type of the result. */
7275 }
7285 }
7287 \f
7288 void
7290 {
7293 current_class_stack
7301 }
7303 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7305 static void
7307 {
7308 tree type;
7310 /* We are re-entering the same class we just left, so we don't
7311 have to search the whole inheritance matrix to find all the
7312 decls to bind again. Instead, we install the cached
7313 class_shadowed list and walk through it binding names. */
7316 /* Restore IDENTIFIER_TYPE_VALUE. */
7318 type;
7321 }
7323 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7324 appropriate for TYPE.
7326 So that we may avoid calls to lookup_name, we cache the _TYPE
7327 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7329 For multiple inheritance, we perform a two-pass depth-first search
7330 of the type lattice. */
7332 void
7334 {
7335 class_stack_node_t csn;
7339 /* Make sure there is enough room for the new entry on the stack. */
7341 {
7343 current_class_stack
7345 current_class_stack_size);
7346 }
7348 /* Insert a new entry on the class stack. */
7355 current_class_depth++;
7357 /* Now set up the new type. */
7363 /* By default, things in classes are private, while things in
7364 structures or unions are public. */
7366 ? access_private_node
7372 {
7373 /* Forcibly remove any old class remnants. */
7375 }
7381 else
7383 }
7385 /* When we exit a toplevel class scope, we save its binding level so
7386 that we can restore it quickly. Here, we've entered some other
7387 class, so we must invalidate our cache. */
7389 void
7391 {
7393 }
7395 /* Get out of the current class scope. If we were in a class scope
7396 previously, that is the one popped to. */
7398 void
7400 {
7403 current_class_depth--;
7409 }
7411 /* Mark the top of the class stack as hidden. */
7413 void
7415 {
7418 }
7420 /* Mark the top of the class stack as un-hidden. */
7422 void
7424 {
7427 }
7429 /* Returns 1 if the class type currently being defined is either T or
7430 a nested type of T. Returns the type from the current_class_stack,
7431 which might be equivalent to but not equal to T in case of
7432 constrained partial specializations. */
7434 tree
7436 {
7444 /* We start looking from 1 because entry 0 is from global scope,
7445 and has no type. */
7447 {
7448 tree c;
7451 else
7452 {
7456 }
7461 }
7463 }
7465 /* If either current_class_type or one of its enclosing classes are derived
7466 from T, return the appropriate type. Used to determine how we found
7467 something via unqualified lookup. */
7469 tree
7471 {
7474 /* The bases of a dependent type are unknown. */
7485 {
7490 }
7493 }
7495 /* Return the outermost enclosing class type that is still open, or
7496 NULL_TREE. */
7498 tree
7500 {
7507 {
7514 }
7516 }
7518 /* Returns the innermost class type which is not a lambda closure type. */
7520 tree
7522 {
7527 }
7529 /* When entering a class scope, all enclosing class scopes' names with
7530 static meaning (static variables, static functions, types and
7531 enumerators) have to be visible. This recursive function calls
7532 pushclass for all enclosing class contexts until global or a local
7533 scope is reached. TYPE is the enclosed class. */
7535 void
7537 {
7538 /* A namespace might be passed in error cases, like A::B:C. */
7546 }
7548 /* Undoes a push_nested_class call. */
7550 void
7552 {
7558 }
7560 /* Returns the number of extern "LANG" blocks we are nested within. */
7562 int
7564 {
7566 }
7568 /* Set global variables CURRENT_LANG_NAME to appropriate value
7569 so that behavior of name-mangling machinery is correct. */
7571 void
7573 {
7580 else
7582 }
7584 /* Get out of the current language scope. */
7586 void
7588 {
7590 }
7591 \f
7592 /* Type instantiation routines. */
7594 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7595 matches the TARGET_TYPE. If there is no satisfactory match, return
7596 error_mark_node, and issue an error & warning messages under
7597 control of FLAGS. Permit pointers to member function if FLAGS
7598 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7599 a template-id, and EXPLICIT_TARGS are the explicitly provided
7600 template arguments.
7602 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7603 is the base path used to reference those member functions. If
7604 the address is resolved to a member function, access checks will be
7605 performed and errors issued if appropriate. */
7607 static tree
7609 tree overload,
7610 tsubst_flags_t complain,
7612 tree explicit_targs,
7613 tree access_path)
7614 {
7615 /* Here's what the standard says:
7617 [over.over]
7619 If the name is a function template, template argument deduction
7620 is done, and if the argument deduction succeeds, the deduced
7621 arguments are used to generate a single template function, which
7622 is added to the set of overloaded functions considered.
7624 Non-member functions and static member functions match targets of
7625 type "pointer-to-function" or "reference-to-function." Nonstatic
7626 member functions match targets of type "pointer-to-member
7627 function;" the function type of the pointer to member is used to
7628 select the member function from the set of overloaded member
7629 functions. If a nonstatic member function is selected, the
7630 reference to the overloaded function name is required to have the
7631 form of a pointer to member as described in 5.3.1.
7633 If more than one function is selected, any template functions in
7634 the set are eliminated if the set also contains a non-template
7635 function, and any given template function is eliminated if the
7636 set contains a second template function that is more specialized
7637 than the first according to the partial ordering rules 14.5.5.2.
7638 After such eliminations, if any, there shall remain exactly one
7639 selected function. */
7642 /* We store the matches in a TREE_LIST rooted here. The functions
7643 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7644 interoperability with most_specialized_instantiation. */
7646 tree fn;
7647 tree target_fn_type;
7649 /* By the time we get here, we should be seeing only real
7650 pointer-to-member types, not the internal POINTER_TYPE to
7651 METHOD_TYPE representation. */
7657 /* Check that the TARGET_TYPE is reasonable. */
7662 /* This is OK, too. */
7665 /* This is OK, too. This comes from a conversion to reference
7666 type. */
7668 else
7669 {
7675 }
7677 /* Non-member functions and static member functions match targets of type
7678 "pointer-to-function" or "reference-to-function." Nonstatic member
7679 functions match targets of type "pointer-to-member-function;" the
7680 function type of the pointer to member is used to select the member
7681 function from the set of overloaded member functions.
7683 So figure out the FUNCTION_TYPE that we want to match against. */
7686 /* If we can find a non-template function that matches, we can just
7687 use it. There's no point in generating template instantiations
7688 if we're just going to throw them out anyhow. But, of course, we
7689 can only do this when we don't *need* a template function. */
7692 {
7696 /* We're not looking for templates just yet. */
7700 /* We're looking for a non-static member, and this isn't
7701 one, or vice versa. */
7704 /* In C++17 we need the noexcept-qualifier to compare types. */
7709 /* See if there's a match. */
7714 }
7716 /* Now, if we've already got a match (or matches), there's no need
7717 to proceed to the template functions. But, if we don't have a
7718 match we need to look at them, too. */
7720 {
7721 tree target_arg_types;
7722 tree target_ret_type;
7725 tree arg;
7739 {
7741 tree instantiation;
7742 tree targs;
7745 /* We're only looking for templates. */
7750 /* We're not looking for a non-static member, and this is
7751 one, or vice versa. */
7756 /* If the template has a deduced return type, don't expose it to
7757 template argument deduction. */
7761 /* Try to do argument deduction. */
7768 /* Instantiation failed. */
7771 /* Constraints must be satisfied. This is done before
7772 return type deduction since that instantiates the
7773 function. */
7777 /* And now force instantiation to do return type deduction. */
7779 {
7785 }
7787 /* In C++17 we need the noexcept-qualifier to compare types. */
7791 /* See if there's a match. */
7796 }
7798 /* Now, remove all but the most specialized of the matches. */
7800 {
7805 NULL_TREE,
7806 NULL_TREE);
7807 }
7808 }
7810 /* Now we should have exactly one function in MATCHES. */
7812 {
7813 /* There were *no* matches. */
7815 {
7820 }
7822 }
7824 {
7825 /* There were too many matches. First check if they're all
7826 the same function. */
7831 /* For multi-versioned functions, more than one match is just fine and
7832 decls_match will return false as they are different. */
7840 {
7842 {
7846 /* Since print_candidates expects the functions in the
7847 TREE_VALUE slot, we flip them here. */
7852 }
7855 }
7856 }
7858 /* Good, exactly one match. Now, convert it to the correct type. */
7863 {
7871 {
7874 }
7875 }
7877 /* If a pointer to a function that is multi-versioned is requested, the
7878 pointer to the dispatcher function is returned instead. This works
7879 well because indirectly calling the function will dispatch the right
7880 function version at run-time. */
7882 {
7886 /* Mark all the versions corresponding to the dispatcher as used. */
7889 }
7891 /* If we're doing overload resolution purely for the purpose of
7892 determining conversion sequences, we should not consider the
7893 function used. If this conversion sequence is selected, the
7894 function will be marked as used at this point. */
7896 {
7897 /* Make =delete work with SFINAE. */
7902 }
7904 /* We could not check access to member functions when this
7905 expression was originally created since we did not know at that
7906 time to which function the expression referred. */
7908 {
7911 }
7915 else
7916 {
7917 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
7918 will mark the function as addressed, but here we must do it
7919 explicitly. */
7923 }
7924 }
7926 /* This function will instantiate the type of the expression given in
7927 RHS to match the type of LHSTYPE. If errors exist, then return
7928 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
7929 we complain on errors. If we are not complaining, never modify rhs,
7930 as overload resolution wants to try many possible instantiations, in
7931 the hope that at least one will work.
7933 For non-recursive calls, LHSTYPE should be a function, pointer to
7934 function, or a pointer to member function. */
7936 tree
7938 {
7945 {
7949 }
7952 {
7961 /* Microsoft allows `A::f' to be resolved to a
7962 pointer-to-member. */
7963 ;
7964 else
7965 {
7970 }
7971 }
7974 {
7977 }
7979 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
7980 deduce any type information. */
7982 {
7986 }
7988 /* If we instantiate a template, and it is a A ?: C expression
7989 with omitted B, look through the SAVE_EXPR. */
7993 /* There are only a few kinds of expressions that may have a type
7994 dependent on overload resolution. */
8000 /* This should really only be used when attempting to distinguish
8001 what sort of a pointer to function we have. For now, any
8002 arithmetic operation which is not supported on pointers
8003 is rejected as an error. */
8006 {
8008 {
8014 /* Do not lose object's side effects. */
8018 }
8025 /* This can happen if we are forming a pointer-to-member for a
8026 member template. */
8029 /* Fall through. */
8032 {
8036 return
8040 }
8044 return
8048 access_path);
8051 {
8056 }
8063 }
8065 }
8066 \f
8067 /* Return the name of the virtual function pointer field
8068 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8069 this may have to look back through base types to find the
8070 ultimate field name. (For single inheritance, these could
8071 all be the same name. Who knows for multiple inheritance). */
8073 static tree
8075 {
8081 {
8087 }
8095 }
8097 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8098 according to [class]:
8099 The class-name is also inserted
8100 into the scope of the class itself. For purposes of access checking,
8101 the inserted class name is treated as if it were a public member name. */
8103 void
8105 {
8122 }
8124 /* Returns 1 if TYPE contains only padding bytes. */
8126 int
8128 {
8136 }
8138 /* Returns true if TYPE contains no actual data, just various
8139 possible combinations of empty classes and possibly a vptr. */
8141 bool
8143 {
8145 {
8146 tree field;
8147 tree binfo;
8148 tree base_binfo;
8151 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8152 out, but we'd like to be able to check this before then. */
8163 /* An unnamed bit-field is not a data member. */
8168 }
8173 }
8175 /* Note that NAME was looked up while the current class was being
8176 defined and that the result of that lookup was DECL. */
8178 void
8180 {
8181 splay_tree names_used;
8183 /* If we're not defining a class, there's nothing to do. */
8189 /* If there's already a binding for this NAME, then we don't have
8190 anything to worry about. */
8203 }
8205 /* Note that NAME was declared (as DECL) in the current class. Check
8206 to see that the declaration is valid. */
8208 void
8210 {
8211 splay_tree names_used;
8212 splay_tree_node n;
8214 /* Look to see if we ever used this name. */
8215 names_used
8219 /* The C language allows members to be declared with a type of the same
8220 name, and the C++ standard says this diagnostic is not required. So
8221 allow it in extern "C" blocks unless predantic is specified.
8222 Allow it in all cases if -ms-extensions is specified. */
8228 {
8229 /* [basic.scope.class]
8231 A name N used in a class S shall refer to the same declaration
8232 in its context and when re-evaluated in the completed scope of
8233 S. */
8238 }
8239 }
8241 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8242 Secondary vtables are merged with primary vtables; this function
8243 will return the VAR_DECL for the primary vtable. */
8245 tree
8247 {
8248 tree decl;
8252 {
8255 }
8259 }
8262 /* Returns the binfo for the primary base of BINFO. If the resulting
8263 BINFO is a virtual base, and it is inherited elsewhere in the
8264 hierarchy, then the returned binfo might not be the primary base of
8265 BINFO in the complete object. Check BINFO_PRIMARY_P or
8266 BINFO_LOST_PRIMARY_P to be sure. */
8268 static tree
8270 {
8271 tree primary_base;
8278 }
8280 /* As above, but iterate until we reach the binfo that actually provides the
8281 vptr for BINFO. */
8283 static tree
8285 {
8289 {
8294 }
8296 }
8298 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8299 type. Note that the virtual inheritance might be above or below BINFO in
8300 the hierarchy. */
8302 bool
8304 {
8308 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8309 a morally virtual base. */
8312 }
8314 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8316 static int
8318 {
8322 }
8324 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8325 INDENT should be zero when called from the top level; it is
8326 incremented recursively. IGO indicates the next expected BINFO in
8327 inheritance graph ordering. */
8329 static tree
8331 dump_flags_t flags,
8332 tree binfo,
8333 tree igo,
8335 {
8337 tree base_binfo;
8345 {
8348 }
8363 {
8367 TFF_PLAIN_IDENTIFIER),
8369 }
8371 {
8374 }
8379 {
8383 {
8387 TFF_PLAIN_IDENTIFIER));
8388 }
8390 {
8394 TFF_PLAIN_IDENTIFIER));
8395 }
8397 {
8401 TFF_PLAIN_IDENTIFIER));
8402 }
8404 {
8408 TFF_PLAIN_IDENTIFIER));
8409 }
8413 }
8419 }
8421 /* Dump the BINFO hierarchy for T. */
8423 static void
8425 {
8437 }
8439 /* Debug interface to hierarchy dumping. */
8441 void
8443 {
8445 }
8447 static void
8449 {
8450 dump_flags_t flags;
8452 {
8455 }
8456 }
8458 static void
8460 {
8461 tree value;
8463 HOST_WIDE_INT elt;
8471 TFF_PLAIN_IDENTIFIER));
8478 }
8480 static void
8482 {
8483 dump_flags_t flags;
8490 {
8497 {
8502 }
8506 }
8509 }
8511 static void
8513 {
8514 dump_flags_t flags;
8521 {
8526 }
8529 }
8531 /* Dump a function or thunk and its thunkees. */
8533 static void
8535 {
8538 tree thunks;
8546 {
8556 else
8562 }
8566 }
8568 /* Dump the thunks for FN. */
8570 void
8572 {
8574 }
8576 /* Virtual function table initialization. */
8578 /* Create all the necessary vtables for T and its base classes. */
8580 static void
8582 {
8583 tree vbase;
8587 /* We lay out the primary and secondary vtables in one contiguous
8588 vtable. The primary vtable is first, followed by the non-virtual
8589 secondary vtables in inheritance graph order. */
8593 /* Then come the virtual bases, also in inheritance graph order. */
8595 {
8599 }
8603 }
8605 /* Initialize the vtable for BINFO with the INITS. */
8607 static void
8609 {
8610 tree decl;
8616 }
8618 /* Build the VTT (virtual table table) for T.
8619 A class requires a VTT if it has virtual bases.
8621 This holds
8622 1 - primary virtual pointer for complete object T
8623 2 - secondary VTTs for each direct non-virtual base of T which requires a
8624 VTT
8625 3 - secondary virtual pointers for each direct or indirect base of T which
8626 has virtual bases or is reachable via a virtual path from T.
8627 4 - secondary VTTs for each direct or indirect virtual base of T.
8629 Secondary VTTs look like complete object VTTs without part 4. */
8631 static void
8633 {
8634 tree type;
8635 tree vtt;
8636 tree index;
8639 /* Build up the initializers for the VTT. */
8644 /* If we didn't need a VTT, we're done. */
8648 /* Figure out the type of the VTT. */
8652 /* Now, build the VTT object itself. */
8655 /* Add the VTT to the vtables list. */
8660 }
8662 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8663 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8664 and CHAIN the vtable pointer for this binfo after construction is
8665 complete. VALUE can also be another BINFO, in which case we recurse. */
8667 static tree
8669 {
8670 tree vt;
8673 {
8679 else
8681 }
8684 }
8686 /* Data for secondary VTT initialization. */
8687 struct secondary_vptr_vtt_init_data
8688 {
8689 /* Is this the primary VTT? */
8692 /* Current index into the VTT. */
8693 tree index;
8695 /* Vector of initializers built up. */
8698 /* The type being constructed by this secondary VTT. */
8699 tree type_being_constructed;
8700 };
8702 /* Recursively build the VTT-initializer for BINFO (which is in the
8703 hierarchy dominated by T). INITS points to the end of the initializer
8704 list to date. INDEX is the VTT index where the next element will be
8705 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8706 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8707 for virtual bases of T. When it is not so, we build the constructor
8708 vtables for the BINFO-in-T variant. */
8710 static void
8713 {
8715 tree b;
8716 tree init;
8717 secondary_vptr_vtt_init_data data;
8720 /* We only need VTTs for subobjects with virtual bases. */
8724 /* We need to use a construction vtable if this is not the primary
8725 VTT. */
8727 {
8730 /* Record the offset in the VTT where this sub-VTT can be found. */
8732 }
8734 /* Add the address of the primary vtable for the complete object. */
8738 {
8741 }
8744 /* Recursively add the secondary VTTs for non-virtual bases. */
8749 /* Add secondary virtual pointers for all subobjects of BINFO with
8750 either virtual bases or reachable along a virtual path, except
8751 subobjects that are non-virtual primary bases. */
8761 /* data.inits might have grown as we added secondary virtual pointers.
8762 Make sure our caller knows about the new vector. */
8766 /* Add the secondary VTTs for virtual bases in inheritance graph
8767 order. */
8769 {
8774 }
8775 else
8776 /* Remove the ctor vtables we created. */
8778 }
8780 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8781 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8783 static tree
8785 {
8788 /* We don't care about bases that don't have vtables. */
8792 /* We're only interested in proper subobjects of the type being
8793 constructed. */
8797 /* We're only interested in bases with virtual bases or reachable
8798 via a virtual path from the type being constructed. */
8803 /* We're not interested in non-virtual primary bases. */
8807 /* Record the index where this secondary vptr can be found. */
8809 {
8814 {
8815 /* It's a primary virtual base, and this is not a
8816 construction vtable. Find the base this is primary of in
8817 the inheritance graph, and use that base's vtable
8818 now. */
8821 }
8822 }
8824 /* Add the initializer for the secondary vptr itself. */
8827 /* Advance the vtt index. */
8832 }
8834 /* Called from build_vtt_inits via dfs_walk. After building
8835 constructor vtables and generating the sub-vtt from them, we need
8836 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8837 binfo of the base whose sub vtt was generated. */
8839 static tree
8841 {
8845 /* If this class has no vtable, none of its bases do. */
8849 /* This might be a primary base, so have no vtable in this
8850 hierarchy. */
8853 /* If we scribbled the construction vtable vptr into BINFO, clear it
8854 out now. */
8860 }
8862 /* Build the construction vtable group for BINFO which is in the
8863 hierarchy dominated by T. */
8865 static void
8867 {
8868 tree type;
8869 tree vtbl;
8870 tree id;
8871 tree vbase;
8874 /* See if we've already created this construction vtable group. */
8880 /* Build a version of VTBL (with the wrong type) for use in
8881 constructing the addresses of secondary vtables in the
8882 construction vtable group. */
8885 /* Don't export construction vtables from shared libraries. Even on
8886 targets that don't support hidden visibility, this tells
8887 can_refer_decl_in_current_unit_p not to assume that it's safe to
8888 access from a different compilation unit (bz 54314). */
8896 /* Add the vtables for each of our virtual bases using the vbase in T
8897 binfo. */
8899 vbase;
8901 {
8902 tree b;
8909 }
8911 /* Figure out the type of the construction vtable. */
8918 /* Initialize the construction vtable. */
8922 }
8924 /* Add the vtbl initializers for BINFO (and its bases other than
8925 non-virtual primaries) to the list of INITS. BINFO is in the
8926 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
8927 the constructor the vtbl inits should be accumulated for. (If this
8928 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
8929 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
8930 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
8931 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
8932 but are not necessarily the same in terms of layout. */
8934 static void
8936 tree orig_binfo,
8937 tree rtti_binfo,
8938 tree vtbl,
8939 tree t,
8941 {
8943 tree base_binfo;
8948 /* If it doesn't have a vptr, we don't do anything. */
8952 /* If we're building a construction vtable, we're not interested in
8953 subobjects that don't require construction vtables. */
8959 /* Build the initializers for the BINFO-in-T vtable. */
8962 /* Walk the BINFO and its bases. We walk in preorder so that as we
8963 initialize each vtable we can figure out at what offset the
8964 secondary vtable lies from the primary vtable. We can't use
8965 dfs_walk here because we need to iterate through bases of BINFO
8966 and RTTI_BINFO simultaneously. */
8968 {
8969 /* Skip virtual bases. */
8975 inits);
8976 }
8977 }
8979 /* Called from accumulate_vtbl_inits. Adds the initializers for the
8980 BINFO vtable to L. */
8982 static void
8984 tree orig_binfo,
8985 tree rtti_binfo,
8986 tree orig_vtbl,
8987 tree t,
8989 {
8996 {
8997 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
8998 primary virtual base. If it is not the same primary in
8999 the hierarchy of T, we'll need to generate a ctor vtable
9000 for it, to place at its location in T. If it is the same
9001 primary, we still need a VTT entry for the vtable, but it
9002 should point to the ctor vtable for the base it is a
9003 primary for within the sub-hierarchy of RTTI_BINFO.
9005 There are three possible cases:
9007 1) We are in the same place.
9008 2) We are a primary base within a lost primary virtual base of
9009 RTTI_BINFO.
9010 3) We are primary to something not a base of RTTI_BINFO. */
9012 tree b;
9015 /* First, look through the bases we are primary to for RTTI_BINFO
9016 or a virtual base. */
9019 {
9024 }
9025 /* If we run out of primary links, keep looking down our
9026 inheritance chain; we might be an indirect primary. */
9030 found:
9032 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9033 base B and it is a base of RTTI_BINFO, this is case 2. In
9034 either case, we share our vtable with LAST, i.e. the
9035 derived-most base within B of which we are a primary. */
9038 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9039 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9040 binfo_ctor_vtable after everything's been set up. */
9043 /* Otherwise, this is case 3 and we get our own. */
9044 }
9051 {
9052 tree index;
9055 /* Add the initializer for this vtable. */
9059 /* Figure out the position to which the VPTR should point. */
9065 }
9068 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9069 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9070 straighten this out. */
9073 /* Throw away any unneeded intializers. */
9075 else
9076 /* For an ordinary vtable, set BINFO_VTABLE. */
9078 }
9083 /* Construct the initializer for BINFO's virtual function table. BINFO
9084 is part of the hierarchy dominated by T. If we're building a
9085 construction vtable, the ORIG_BINFO is the binfo we should use to
9086 find the actual function pointers to put in the vtable - but they
9087 can be overridden on the path to most-derived in the graph that
9088 ORIG_BINFO belongs. Otherwise,
9089 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9090 BINFO that should be indicated by the RTTI information in the
9091 vtable; it will be a base class of T, rather than T itself, if we
9092 are building a construction vtable.
9094 The value returned is a TREE_LIST suitable for wrapping in a
9095 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9096 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9097 number of non-function entries in the vtable.
9099 It might seem that this function should never be called with a
9100 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9101 base is always subsumed by a derived class vtable. However, when
9102 we are building construction vtables, we do build vtables for
9103 primary bases; we need these while the primary base is being
9104 constructed. */
9106 static void
9108 tree orig_binfo,
9109 tree t,
9110 tree rtti_binfo,
9113 {
9114 tree v;
9115 vtbl_init_data vid;
9117 tree vbinfo;
9121 /* Initialize VID. */
9129 /* The first vbase or vcall offset is at index -3 in the vtable. */
9132 /* Add entries to the vtable for RTTI. */
9135 /* Create an array for keeping track of the functions we've
9136 processed. When we see multiple functions with the same
9137 signature, we share the vcall offsets. */
9139 /* Add the vcall and vbase offset entries. */
9142 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9143 build_vbase_offset_vtbl_entries. */
9148 /* If the target requires padding between data entries, add that now. */
9150 {
9155 /* Move data entries into their new positions and add padding
9156 after the new positions. Iterate backwards so we don't
9157 overwrite entries that we would need to process later. */
9160 ix--)
9161 {
9169 {
9173 null_pointer_node);
9174 }
9175 }
9176 }
9181 /* The initializers for virtual functions were built up in reverse
9182 order. Straighten them out and add them to the running list in one
9183 step. */
9192 /* Go through all the ordinary virtual functions, building up
9193 initializers. */
9195 {
9196 tree delta;
9197 tree vcall_index;
9204 {
9208 {
9211 }
9213 }
9215 /* If the only definition of this function signature along our
9216 primary base chain is from a lost primary, this vtable slot will
9217 never be used, so just zero it out. This is important to avoid
9218 requiring extra thunks which cannot be generated with the function.
9220 We first check this in update_vtable_entry_for_fn, so we handle
9221 restored primary bases properly; we also need to do it here so we
9222 zero out unused slots in ctor vtables, rather than filling them
9223 with erroneous values (though harmless, apart from relocation
9224 costs). */
9229 {
9230 /* Pull the offset for `this', and the function to call, out of
9231 the list. */
9238 /* You can't call an abstract virtual function; it's abstract.
9239 So, we replace these functions with __pure_virtual. */
9241 {
9244 {
9246 abort_fndecl_addr
9250 }
9251 }
9252 /* Likewise for deleted virtuals. */
9254 {
9256 {
9260 dvirt_fn = push_library_fn
9264 }
9269 }
9270 else
9271 {
9273 {
9278 }
9279 /* Take the address of the function, considering it to be of an
9280 appropriate generic type. */
9284 /* Don't refer to a virtual destructor from a constructor
9285 vtable or a vtable for an abstract class, since destroying
9286 an object under construction is undefined behavior and we
9287 don't want it to be considered a candidate for speculative
9288 devirtualization. But do create the thunk for ABI
9289 compliance. */
9294 }
9295 }
9297 /* And add it to the chain of initializers. */
9299 {
9304 else
9306 {
9312 }
9313 }
9314 else
9316 }
9317 }
9319 /* Adds to vid->inits the initializers for the vbase and vcall
9320 offsets in BINFO, which is in the hierarchy dominated by T. */
9322 static void
9324 {
9325 tree b;
9327 /* If this is a derived class, we must first create entries
9328 corresponding to the primary base class. */
9333 /* Add the vbase entries for this base. */
9335 /* Add the vcall entries for this base. */
9337 }
9339 /* Returns the initializers for the vbase offset entries in the vtable
9340 for BINFO (which is part of the class hierarchy dominated by T), in
9341 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9342 where the next vbase offset will go. */
9344 static void
9346 {
9347 tree vbase;
9348 tree t;
9349 tree non_primary_binfo;
9351 /* If there are no virtual baseclasses, then there is nothing to
9352 do. */
9358 /* We might be a primary base class. Go up the inheritance hierarchy
9359 until we find the most derived class of which we are a primary base:
9360 it is the offset of that which we need to use. */
9363 {
9364 tree b;
9366 /* If we have reached a virtual base, then it must be a primary
9367 base (possibly multi-level) of vid->binfo, or we wouldn't
9368 have called build_vcall_and_vbase_vtbl_entries for it. But it
9369 might be a lost primary, so just skip down to vid->binfo. */
9371 {
9374 }
9380 }
9382 /* Go through the virtual bases, adding the offsets. */
9384 vbase;
9386 {
9387 tree b;
9388 tree delta;
9393 /* Find the instance of this virtual base in the complete
9394 object. */
9397 /* If we've already got an offset for this virtual base, we
9398 don't need another one. */
9403 /* Figure out where we can find this vbase offset. */
9412 /* The vbase offset had better be the same. */
9415 /* The next vbase will come at a more negative offset. */
9419 /* The initializer is the delta from BINFO to this virtual base.
9420 The vbase offsets go in reverse inheritance-graph order, and
9421 we are walking in inheritance graph order so these end up in
9422 the right order. */
9429 }
9430 }
9432 /* Adds the initializers for the vcall offset entries in the vtable
9433 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9434 to VID->INITS. */
9436 static void
9438 {
9439 /* We only need these entries if this base is a virtual base. We
9440 compute the indices -- but do not add to the vtable -- when
9441 building the main vtable for a class. */
9444 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9445 correspond to VID->DERIVED), we are building a primary
9446 construction virtual table. Since this is a primary
9447 virtual table, we do not need the vcall offsets for
9448 BINFO. */
9450 {
9451 /* We need a vcall offset for each of the virtual functions in this
9452 vtable. For example:
9454 class A { virtual void f (); };
9455 class B1 : virtual public A { virtual void f (); };
9456 class B2 : virtual public A { virtual void f (); };
9457 class C: public B1, public B2 { virtual void f (); };
9459 A C object has a primary base of B1, which has a primary base of A. A
9460 C also has a secondary base of B2, which no longer has a primary base
9461 of A. So the B2-in-C construction vtable needs a secondary vtable for
9462 A, which will adjust the A* to a B2* to call f. We have no way of
9463 knowing what (or even whether) this offset will be when we define B2,
9464 so we store this "vcall offset" in the A sub-vtable and look it up in
9465 a "virtual thunk" for B2::f.
9467 We need entries for all the functions in our primary vtable and
9468 in our non-virtual bases' secondary vtables. */
9470 /* If we are just computing the vcall indices -- but do not need
9471 the actual entries -- not that. */
9474 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9476 }
9477 }
9479 /* Build vcall offsets, starting with those for BINFO. */
9481 static void
9483 {
9485 tree primary_binfo;
9486 tree base_binfo;
9488 /* Don't walk into virtual bases -- except, of course, for the
9489 virtual base for which we are building vcall offsets. Any
9490 primary virtual base will have already had its offsets generated
9491 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9495 /* If BINFO has a primary base, process it first. */
9500 /* Add BINFO itself to the list. */
9503 /* Scan the non-primary bases of BINFO. */
9507 }
9509 /* Called from build_vcall_offset_vtbl_entries_r. */
9511 static void
9513 {
9514 /* Make entries for the rest of the virtuals. */
9515 tree orig_fn;
9517 /* The ABI requires that the methods be processed in declaration
9518 order. */
9520 orig_fn;
9524 }
9526 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9528 static void
9530 {
9532 tree vcall_offset;
9533 tree derived_entry;
9535 /* If there is already an entry for a function with the same
9536 signature as FN, then we do not need a second vcall offset.
9537 Check the list of functions already present in the derived
9538 class vtable. */
9540 {
9542 /* We only use one vcall offset for virtual destructors,
9543 even though there are two virtual table entries. */
9547 }
9549 /* If we are building these vcall offsets as part of building
9550 the vtable for the most derived class, remember the vcall
9551 offset. */
9553 {
9556 }
9558 /* The next vcall offset will be found at a more negative
9559 offset. */
9563 /* Keep track of this function. */
9567 {
9568 tree base;
9569 tree fn;
9571 /* Find the overriding function. */
9575 else
9576 {
9579 /* The vbase we're working on is a primary base of
9580 vid->binfo. But it might be a lost primary, so its
9581 BINFO_OFFSET might be wrong, so we just use the
9582 BINFO_OFFSET from vid->binfo. */
9588 vcall_offset);
9589 }
9590 /* Add the initializer to the vtable. */
9592 }
9593 }
9595 /* Return vtbl initializers for the RTTI entries corresponding to the
9596 BINFO's vtable. The RTTI entries should indicate the object given
9597 by VID->rtti_binfo. */
9599 static void
9601 {
9602 tree b;
9603 tree t;
9604 tree offset;
9605 tree decl;
9606 tree init;
9610 /* To find the complete object, we will first convert to our most
9611 primary base, and then add the offset in the vtbl to that value. */
9616 /* The second entry is the address of the typeinfo object. */
9619 else
9622 /* Convert the declaration to a type that can be stored in the
9623 vtable. */
9627 /* Add the offset-to-top entry. It comes earlier in the vtable than
9628 the typeinfo entry. Convert the offset to look like a
9629 function pointer, so that we can put it in the vtable. */
9632 }
9634 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9635 accessibility. */
9637 bool
9639 {
9642 }
9644 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9646 bool
9648 {
9652 }
9654 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9655 class between them, if any. */
9657 tree
9659 {
9671 {
9674 }
9678 }