| blob | 8348552a05b613762b2f385cf608d2372c8ac96c |
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 {
2875 {
2876 /* We're generally only interested in entities the user
2877 declared, but we also find nested classes by noticing
2878 the TYPE_DECL that we create implicitly. You're
2879 allowed to put one anonymous union inside another,
2880 though, so we explicitly tolerate that. We use
2881 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2882 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. */
2893 {
2896 "%q#D invalid; an anonymous union can "
2898 else
2900 "%q#D invalid; an anonymous struct can "
2902 }
2904 }
2907 {
2909 {
2913 else
2916 }
2918 {
2922 else
2925 }
2926 }
2931 /* Recurse into the anonymous aggregates to handle correctly
2932 access control (c++/24926):
2934 class A {
2935 union {
2936 union {
2937 int i;
2938 };
2939 };
2940 };
2942 int j=A().i; */
2946 }
2947 }
2949 /* Check for things that are invalid. There are probably plenty of other
2950 things we should check for also. */
2952 static void
2954 {
2956 {
2965 }
2966 }
2968 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2969 will be used later during class template instantiation.
2970 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2971 a non-static member data (FIELD_DECL), a member function
2972 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2973 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2974 When FRIEND_P is nonzero, T is either a friend class
2975 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2976 (FUNCTION_DECL, TEMPLATE_DECL). */
2978 void
2980 {
2981 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2986 }
2988 /* This function is called from declare_virt_assop_and_dtor via
2989 dfs_walk_all.
2991 DATA is a type that direcly or indirectly inherits the base
2992 represented by BINFO. If BINFO contains a virtual assignment [copy
2993 assignment or move assigment] operator or a virtual constructor,
2994 declare that function in DATA if it hasn't been already declared. */
2996 static tree
2998 {
3006 /* A base without a vtable needs no modification, and its bases
3007 are uninteresting. */
3011 /* If this is a primary base, then we have already looked at the
3012 virtual functions of its vtable. */
3016 {
3020 {
3025 }
3029 }
3032 }
3034 /* If the class type T has a direct or indirect base that contains a
3035 virtual assignment operator or a virtual destructor, declare that
3036 function in T if it hasn't been already declared. */
3038 static void
3040 {
3048 dfs_declare_virt_assop_and_dtor,
3050 }
3052 /* Declare the inheriting constructor for class T inherited from base
3053 constructor CTOR with the parameter array PARMS of size NPARMS. */
3055 static void
3057 {
3060 /* We don't declare an inheriting ctor that would be a default,
3061 copy or move ctor for derived or base. */
3066 {
3070 }
3079 {
3082 }
3083 }
3085 /* Declare all the inheriting constructors for class T inherited from base
3086 constructor CTOR. */
3088 static void
3090 {
3094 {
3100 }
3105 {
3109 }
3112 {
3116 }
3117 }
3119 /* Create default constructors, assignment operators, and so forth for
3120 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3121 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3122 the class cannot have a default constructor, copy constructor
3123 taking a const reference argument, or an assignment operator taking
3124 a const reference, respectively. */
3126 static void
3130 {
3131 /* Destructor. */
3133 /* In general, we create destructors lazily. */
3142 /* [class.ctor]
3144 If there is no user-declared constructor for a class, a default
3145 constructor is implicitly declared. */
3147 {
3152 /* Don't force the declaration to get a hard answer; if the
3153 definition would have made the class non-literal, it will still be
3154 non-literal because of the base or member in question, and that
3155 gives a better diagnostic. */
3157 }
3159 /* [class.ctor]
3161 If a class definition does not explicitly declare a copy
3162 constructor, one is declared implicitly. */
3164 {
3170 }
3172 /* If there is no assignment operator, one will be created if and
3173 when it is needed. For now, just record whether or not the type
3174 of the parameter to the assignment operator will be a const or
3175 non-const reference. */
3177 {
3183 }
3185 /* We can't be lazy about declaring functions that might override
3186 a virtual function from a base class. */
3190 {
3194 {
3195 /* declare, then remove the decl */
3203 }
3204 else
3206 }
3207 }
3209 /* FIELD is a bit-field. We are finishing the processing for its
3210 enclosing type. Issue any appropriate messages and set appropriate
3211 flags. Returns false if an error has been diagnosed. */
3213 static bool
3215 {
3217 tree w;
3219 /* Extract the declared width of the bitfield, which has been
3220 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3223 /* Remove the bit-field width indicator so that the rest of the
3224 compiler does not treat that value as a qualifier. */
3227 /* Detect invalid bit-field type. */
3229 {
3232 }
3233 else
3234 {
3236 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3239 /* detect invalid field size. */
3245 {
3248 }
3250 {
3253 }
3255 {
3258 }
3268 {
3274 }
3275 }
3278 {
3282 }
3283 else
3284 {
3285 /* Non-bit-fields are aligned for their type. */
3289 }
3290 }
3292 /* FIELD is a non bit-field. We are finishing the processing for its
3293 enclosing type T. Issue any appropriate messages and set appropriate
3294 flags. */
3296 static bool
3298 tree t,
3301 {
3305 /* In C++98 an anonymous union cannot contain any fields which would change
3306 the settings of CANT_HAVE_CONST_CTOR and friends. */
3308 ;
3309 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3310 structs. So, we recurse through their fields here. */
3312 {
3317 cant_have_const_ctor,
3318 no_const_asn_ref);
3319 }
3320 /* Check members with class type for constructors, destructors,
3321 etc. */
3323 {
3324 /* Never let anything with uninheritable virtuals
3325 make it through without complaint. */
3329 {
3334 field);
3339 field);
3341 {
3345 }
3346 }
3347 else
3348 {
3361 }
3370 }
3375 /* `build_class_init_list' does not recognize
3376 non-FIELD_DECLs. */
3380 }
3382 /* Check the data members (both static and non-static), class-scoped
3383 typedefs, etc., appearing in the declaration of T. Issue
3384 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3385 declaration order) of access declarations; each TREE_VALUE in this
3386 list is a USING_DECL.
3388 In addition, set the following flags:
3390 EMPTY_P
3391 The class is empty, i.e., contains no non-static data members.
3393 CANT_HAVE_CONST_CTOR_P
3394 This class cannot have an implicitly generated copy constructor
3395 taking a const reference.
3397 CANT_HAVE_CONST_ASN_REF
3398 This class cannot have an implicitly generated assignment
3399 operator taking a const reference.
3401 All of these flags should be initialized before calling this
3402 function.
3404 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3405 fields can be added by adding to this chain. */
3407 static void
3411 {
3419 /* Assume there are no access declarations. */
3421 /* Assume this class has no pointer members. */
3423 /* Assume none of the members of this class have default
3424 initializations. */
3428 {
3436 {
3437 /* Save the access declarations for our caller. */
3440 }
3447 /* FIXME: We should fold in the checking from check_methods. */
3450 /* If we've gotten this far, it's a data member, possibly static,
3451 or an enumerator. */
3455 /* When this goes into scope, it will be a non-local reference. */
3459 {
3460 /* [class.union] (C++98)
3462 If a union contains a static data member, or a member of
3463 reference type, the program is ill-formed.
3465 In C++11 [class.union] says:
3466 If a union contains a non-static data member of reference type
3467 the program is ill-formed. */
3469 {
3473 }
3476 {
3480 }
3481 }
3483 /* Perform error checking that did not get done in
3484 grokdeclarator. */
3486 {
3490 }
3492 {
3496 }
3504 /* Now it can only be a FIELD_DECL. */
3509 /* If at least one non-static data member is non-literal, the whole
3510 class becomes non-literal. Per Core/1453, volatile non-static
3511 data members and base classes are also not allowed.
3512 Note: if the type is incomplete we will complain later on. */
3517 /* A standard-layout class is a class that:
3518 ...
3519 has the same access control (Clause 11) for all non-static data members,
3520 ... */
3527 /* If this is of reference type, check if it needs an init. */
3529 {
3535 {
3536 /* ARM $12.6.2: [A member initializer list] (or, for an
3537 aggregate, initialization by a brace-enclosed list) is the
3538 only way to initialize nonstatic const and reference
3539 members. */
3542 }
3543 }
3548 {
3550 {
3551 warning_at
3554 x);
3556 }
3560 }
3564 /* We don't treat zero-width bitfields as making a class
3565 non-empty. */
3566 ;
3567 else
3568 {
3569 /* The class is non-empty. */
3571 /* The class is not even nearly empty. */
3573 /* If one of the data members contains an empty class,
3574 so does T. */
3578 }
3580 /* This is used by -Weffc++ (see below). Warn only for pointers
3581 to members which might hold dynamic memory. So do not warn
3582 for pointers to functions or pointers to members. */
3588 {
3593 }
3599 {
3601 {
3605 }
3607 {
3611 }
3612 }
3615 /* DR 148 now allows pointers to members (which are POD themselves),
3616 to be allowed in POD structs. */
3625 /* We set DECL_C_BIT_FIELD in grokbitfield.
3626 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3631 {
3636 }
3638 /* Now that we've removed bit-field widths from DECL_INITIAL,
3639 anything left in DECL_INITIAL is an NSDMI that makes the class
3640 non-aggregate in C++11. */
3644 /* If any field is const, the structure type is pseudo-const. */
3646 {
3651 {
3652 /* ARM $12.6.2: [A member initializer list] (or, for an
3653 aggregate, initialization by a brace-enclosed list) is the
3654 only way to initialize nonstatic const and reference
3655 members. */
3658 }
3659 }
3660 /* A field that is pseudo-const makes the structure likewise. */
3662 {
3667 }
3669 /* Core issue 80: A nonstatic data member is required to have a
3670 different name from the class iff the class has a
3671 user-declared constructor. */
3676 }
3678 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3679 it should also define a copy constructor and an assignment operator to
3680 implement the correct copy semantic (deep vs shallow, etc.). As it is
3681 not feasible to check whether the constructors do allocate dynamic memory
3682 and store it within members, we approximate the warning like this:
3684 -- Warn only if there are members which are pointers
3685 -- Warn only if there is a non-trivial constructor (otherwise,
3686 there cannot be memory allocated).
3687 -- Warn only if there is a non-trivial destructor. We assume that the
3688 user at least implemented the cleanup correctly, and a destructor
3689 is needed to free dynamic memory.
3691 This seems enough for practical purposes. */
3693 && has_pointers
3697 {
3701 {
3706 }
3710 }
3712 /* Non-static data member initializers make the default constructor
3713 non-trivial. */
3715 {
3718 }
3720 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3724 /* Check anonymous struct/anonymous union fields. */
3727 /* We've built up the list of access declarations in reverse order.
3728 Fix that now. */
3730 }
3732 /* If TYPE is an empty class type, records its OFFSET in the table of
3733 OFFSETS. */
3735 static int
3737 {
3738 splay_tree_node n;
3743 /* Record the location of this empty object in OFFSETS. */
3751 type,
3755 }
3757 /* Returns nonzero if TYPE is an empty class type and there is
3758 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3760 static int
3762 {
3763 splay_tree_node n;
3764 tree t;
3769 /* Record the location of this empty object in OFFSETS. */
3779 }
3781 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3782 F for every subobject, passing it the type, offset, and table of
3783 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3784 be traversed.
3786 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3787 than MAX_OFFSET will not be walked.
3789 If F returns a nonzero value, the traversal ceases, and that value
3790 is returned. Otherwise, returns zero. */
3792 static int
3794 subobject_offset_fn f,
3795 tree offset,
3796 splay_tree offsets,
3797 tree max_offset,
3799 {
3803 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3804 stop. */
3812 {
3815 }
3818 {
3819 tree field;
3820 tree binfo;
3823 /* Avoid recursing into objects that are not interesting. */
3827 /* Record the location of TYPE. */
3832 /* Iterate through the direct base classes of TYPE. */
3836 {
3837 tree binfo_offset;
3842 tree orig_binfo;
3843 /* We cannot rely on BINFO_OFFSET being set for the base
3844 class yet, but the offsets for direct non-virtual
3845 bases can be calculated by going back to the TYPE. */
3848 offset,
3852 f,
3853 binfo_offset,
3854 offsets,
3855 max_offset,
3859 }
3862 {
3866 /* Iterate through the virtual base classes of TYPE. In G++
3867 3.2, we included virtual bases in the direct base class
3868 loop above, which results in incorrect results; the
3869 correct offsets for virtual bases are only known when
3870 working with the most derived type. */
3874 {
3876 f,
3878 offset,
3880 offsets,
3881 max_offset,
3885 }
3886 else
3887 {
3888 /* We still have to walk the primary base, if it is
3889 virtual. (If it is non-virtual, then it was walked
3890 above.) */
3896 {
3897 r = (walk_subobject_offsets
3902 }
3903 }
3904 }
3906 /* Iterate through the fields of TYPE. */
3911 {
3912 tree field_offset;
3917 f,
3919 offset,
3920 field_offset),
3921 offsets,
3922 max_offset,
3926 }
3927 }
3929 {
3932 tree index;
3934 /* Avoid recursing into objects that are not interesting. */
3937 || !domain
3941 /* Step through each of the elements in the array. */
3945 {
3947 f,
3948 offset,
3949 offsets,
3950 max_offset,
3956 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3957 there's no point in iterating through the remaining
3958 elements of the array. */
3961 }
3962 }
3965 }
3967 /* Record all of the empty subobjects of TYPE (either a type or a
3968 binfo). If IS_DATA_MEMBER is true, then a non-static data member
3969 is being placed at OFFSET; otherwise, it is a base class that is
3970 being placed at OFFSET. */
3972 static void
3974 tree offset,
3975 splay_tree offsets,
3977 {
3978 tree max_offset;
3979 /* If recording subobjects for a non-static data member or a
3980 non-empty base class , we do not need to record offsets beyond
3981 the size of the biggest empty class. Additional data members
3982 will go at the end of the class. Additional base classes will go
3983 either at offset zero (if empty, in which case they cannot
3984 overlap with offsets past the size of the biggest empty class) or
3985 at the end of the class.
3987 However, if we are placing an empty base class, then we must record
3988 all offsets, as either the empty class is at offset zero (where
3989 other empty classes might later be placed) or at the end of the
3990 class (where other objects might then be placed, so other empty
3991 subobjects might later overlap). */
3995 else
3999 }
4001 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4002 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4003 virtual bases of TYPE are examined. */
4005 static int
4007 tree offset,
4008 splay_tree offsets,
4010 {
4011 splay_tree_node max_node;
4013 /* Get the node in OFFSETS that indicates the maximum offset where
4014 an empty subobject is located. */
4016 /* If there aren't any empty subobjects, then there's no point in
4017 performing this check. */
4023 vbases_p);
4024 }
4026 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4027 non-static data member of the type indicated by RLI. BINFO is the
4028 binfo corresponding to the base subobject, OFFSETS maps offsets to
4029 types already located at those offsets. This function determines
4030 the position of the DECL. */
4032 static void
4034 tree decl,
4035 tree binfo,
4036 splay_tree offsets)
4037 {
4040 tree type;
4043 {
4044 /* For the purposes of determining layout conflicts, we want to
4045 use the class type of BINFO; TREE_TYPE (DECL) will be the
4046 CLASSTYPE_AS_BASE version, which does not contain entries for
4047 zero-sized bases. */
4050 }
4051 else
4052 {
4055 }
4057 /* Try to place the field. It may take more than one try if we have
4058 a hard time placing the field without putting two objects of the
4059 same type at the same address. */
4061 {
4064 /* Place this field. */
4068 /* We have to check to see whether or not there is already
4069 something of the same type at the offset we're about to use.
4070 For example, consider:
4072 struct S {};
4073 struct T : public S { int i; };
4074 struct U : public S, public T {};
4076 Here, we put S at offset zero in U. Then, we can't put T at
4077 offset zero -- its S component would be at the same address
4078 as the S we already allocated. So, we have to skip ahead.
4079 Since all data members, including those whose type is an
4080 empty class, have nonzero size, any overlap can happen only
4081 with a direct or indirect base-class -- it can't happen with
4082 a data member. */
4083 /* In a union, overlap is permitted; all members are placed at
4084 offset zero. */
4089 {
4090 /* Strip off the size allocated to this field. That puts us
4091 at the first place we could have put the field with
4092 proper alignment. */
4095 /* Bump up by the alignment required for the type. */
4096 rli->bitpos
4102 }
4105 {
4106 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4107 the offset wasn't aligned like a pointer when we started to
4108 layout this field, that affects its position. */
4111 {
4114 "alignment of %qD increased in -fabi-version=9 "
4116 else
4119 }
4121 }
4122 else
4123 /* There was no conflict. We're done laying out this field. */
4125 }
4127 /* Now that we know where it will be placed, update its
4128 BINFO_OFFSET. */
4130 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4131 this point because their BINFO_OFFSET is copied from another
4132 hierarchy. Therefore, we may not need to add the entire
4133 OFFSET. */
4139 }
4141 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4143 static int
4145 tree offset,
4147 {
4149 }
4151 /* Layout the empty base BINFO. EOC indicates the byte currently just
4152 past the end of the class, and should be correctly aligned for a
4153 class of the type indicated by BINFO; OFFSETS gives the offsets of
4154 the empty bases allocated so far. T is the most derived
4155 type. Return nonzero iff we added it at the end. */
4157 static bool
4160 {
4161 tree alignment;
4165 /* This routine should only be used for empty classes. */
4170 propagate_binfo_offsets
4174 /* This is an empty base class. We first try to put it at offset
4175 zero. */
4178 offsets,
4180 {
4181 /* That didn't work. Now, we move forward from the next
4182 available spot in the class. */
4186 {
4189 offsets,
4191 /* We finally found a spot where there's no overlap. */
4194 /* There's overlap here, too. Bump along to the next spot. */
4196 }
4197 }
4200 {
4205 }
4208 }
4210 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4211 fields at NEXT_FIELD, and return it. */
4213 static tree
4215 {
4216 /* Create the FIELD_DECL. */
4224 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4226 else
4227 {
4230 }
4236 /* Add the new FIELD_DECL to the list of fields for T. */
4242 }
4244 /* Layout the base given by BINFO in the class indicated by RLI.
4245 *BASE_ALIGN is a running maximum of the alignments of
4246 any base class. OFFSETS gives the location of empty base
4247 subobjects. T is the most derived type. Return nonzero if the new
4248 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4249 *NEXT_FIELD, unless BINFO is for an empty base class.
4251 Returns the location at which the next field should be inserted. */
4256 {
4261 /* This error is now reported in xref_tag, thus giving better
4262 location information. */
4265 /* Place the base class. */
4267 {
4268 tree decl;
4270 /* The containing class is non-empty because it has a non-empty
4271 base class. */
4274 /* Create the FIELD_DECL. */
4277 /* Try to place the field. It may take more than one try if we
4278 have a hard time placing the field without putting two
4279 objects of the same type at the same address. */
4281 }
4282 else
4283 {
4284 tree eoc;
4287 /* On some platforms (ARM), even empty classes will not be
4288 byte-aligned. */
4293 /* A nearly-empty class "has no proper base class that is empty,
4294 not morally virtual, and at an offset other than zero." */
4296 {
4299 /* The check above (used in G++ 3.2) is insufficient because
4300 an empty class placed at offset zero might itself have an
4301 empty base at a nonzero offset. */
4303 empty_base_at_nonzero_offset_p,
4304 size_zero_node,
4309 }
4311 /* We used to not create a FIELD_DECL for empty base classes because of
4312 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4313 be a problem anymore. We need them to handle initialization of C++17
4314 aggregate bases. */
4316 {
4321 }
4323 /* An empty virtual base causes a class to be non-empty
4324 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4325 here because that was already done when the virtual table
4326 pointer was created. */
4327 }
4329 /* Record the offsets of BINFO and its base subobjects. */
4332 offsets,
4336 }
4338 /* Layout all of the non-virtual base classes. Record empty
4339 subobjects in OFFSETS. T is the most derived type. Return nonzero
4340 if the type cannot be nearly empty. The fields created
4341 corresponding to the base classes will be inserted at
4342 *NEXT_FIELD. */
4344 static void
4347 {
4348 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4349 subobjects. */
4354 /* The primary base class is always allocated first. */
4359 /* Now allocate the rest of the bases. */
4361 {
4362 tree base_binfo;
4366 /* The primary base was already allocated above, so we don't
4367 need to allocate it again here. */
4371 /* Virtual bases are added at the end (a primary virtual base
4372 will have already been added). */
4378 }
4379 }
4381 /* Go through the TYPE_FIELDS of T issuing any appropriate
4382 diagnostics, figuring out which methods override which other
4383 methods, and so forth. */
4385 static void
4387 {
4390 {
4396 /* The name of the field is the original field name
4397 Save this in auxiliary field for later overloading. */
4399 {
4403 }
4405 /* All user-provided destructors are non-trivial.
4406 Constructors and assignment ops are handled in
4407 grok_special_member_properties. */
4414 "%<transaction_safe_dynamic%> may only be specified for "
4416 }
4417 }
4419 /* FN is a constructor or destructor. Clone the declaration to create
4420 a specialized in-charge or not-in-charge version, as indicated by
4421 NAME. */
4423 static tree
4425 {
4426 tree parms;
4427 tree clone;
4429 /* Copy the function. */
4431 /* Reset the function name. */
4433 /* Remember where this function came from. */
4435 /* Make it easy to find the CLONE given the FN. */
4439 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4441 {
4448 }
4449 else
4450 {
4451 // Clone constraints.
4455 }
4460 /* There's no pending inline data for this function. */
4464 /* The base-class destructor is not virtual. */
4466 {
4470 }
4476 /* If there was an in-charge parameter, drop it from the function
4477 type. */
4479 {
4480 tree basetype;
4481 tree parmtypes;
4482 tree exceptions;
4487 /* Skip the `this' parameter. */
4489 /* Skip the in-charge parameter. */
4491 /* And the VTT parm, in a complete [cd]tor. */
4496 {
4497 /* If we're omitting inherited parms, that just leaves the VTT. */
4500 }
4504 parmtypes);
4507 exceptions);
4511 }
4513 /* Copy the function parameters. */
4515 /* Remove the in-charge parameter. */
4517 {
4521 }
4522 /* And the VTT parm, in a complete [cd]tor. */
4524 {
4527 else
4528 {
4532 }
4533 }
4535 /* A base constructor inheriting from a virtual base doesn't get the
4536 arguments. */
4541 {
4544 }
4546 /* Create the RTL for this function. */
4551 }
4553 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4554 not invoke this function directly.
4556 For a non-thunk function, returns the address of the slot for storing
4557 the function it is a clone of. Otherwise returns NULL_TREE.
4559 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4560 cloned_function is unset. This is to support the separate
4561 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4562 on a template makes sense, but not the former. */
4564 tree *
4566 {
4574 {
4575 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4578 else
4579 #endif
4581 }
4586 else
4588 }
4590 /* Produce declarations for all appropriate clones of FN. If
4591 UPDATE_METHODS is true, the clones are added to the
4592 CLASSTYPE_MEMBER_VEC. */
4594 void
4596 {
4597 tree clone;
4599 /* Avoid inappropriate cloning. */
4605 {
4606 /* For each constructor, we need two variants: an in-charge version
4607 and a not-in-charge version. */
4614 }
4615 else
4616 {
4619 /* For each destructor, we need three variants: an in-charge
4620 version, a not-in-charge version, and an in-charge deleting
4621 version. We clone the deleting version first because that
4622 means it will go second on the TYPE_FIELDS list -- and that
4623 corresponds to the correct layout order in the virtual
4624 function table.
4626 For a non-virtual destructor, we do not build a deleting
4627 destructor. */
4629 {
4633 }
4640 }
4642 /* Note that this is an abstract function that is never emitted. */
4644 }
4646 /* DECL is an in charge constructor, which is being defined. This will
4647 have had an in class declaration, from whence clones were
4648 declared. An out-of-class definition can specify additional default
4649 arguments. As it is the clones that are involved in overload
4650 resolution, we must propagate the information from the DECL to its
4651 clones. */
4653 void
4655 {
4656 tree clone;
4660 {
4667 /* Skip the 'this' parameter. */
4683 {
4685 {
4689 }
4695 {
4696 /* A default parameter has been added. Adjust the
4697 clone's parameters. */
4701 tree type;
4706 {
4709 clone_parms);
4711 }
4714 clone_parms);
4723 }
4724 }
4726 }
4727 }
4729 /* For each of the constructors and destructors in T, create an
4730 in-charge and not-in-charge variant. */
4732 static void
4734 {
4735 /* While constructors can be via a using declaration, at this point
4736 we no longer need to know that. */
4742 }
4744 /* Deduce noexcept for a destructor DTOR. */
4746 void
4748 {
4751 noexcept_deferred_spec);
4752 }
4754 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4755 of TYPE for virtual functions which FNDECL overrides. Return a
4756 mask of the tm attributes found therein. */
4758 static int
4760 {
4762 tree base_binfo;
4766 {
4774 {
4778 else
4781 }
4782 else
4784 }
4787 }
4789 /* Subroutine of set_method_tm_attributes. Handle the checks and
4790 inheritance for one virtual method FNDECL. */
4792 static void
4794 {
4795 tree tm_attr;
4800 /* If FNDECL doesn't actually override anything (i.e. T is the
4801 class that first declares FNDECL virtual), then we're done. */
4808 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4809 tm_pure must match exactly, otherwise no weakening of
4810 tm_safe > tm_callable > nothing. */
4811 /* ??? The tm_pure attribute didn't make the transition to the
4812 multivendor language spec. */
4814 {
4816 {
4819 }
4820 }
4821 /* If the overridden function is tm_pure, then FNDECL must be. */
4824 /* Look for base class combinations that cannot be satisfied. */
4826 {
4832 }
4833 /* If FNDECL did not declare an attribute, then inherit the most
4834 restrictive one. */
4836 {
4838 }
4839 /* Otherwise validate that we're not weaker than a function
4840 that is being overridden. */
4841 else
4842 {
4846 }
4849 err_override:
4853 }
4855 /* For each of the methods in T, propagate a class-level tm attribute. */
4857 static void
4859 {
4862 /* Don't bother collecting tm attributes if transactional memory
4863 support is not enabled. */
4867 /* Process virtual methods first, as they inherit directly from the
4868 base virtual function and also require validation of new attributes. */
4870 {
4871 tree vchain;
4874 {
4879 }
4880 }
4882 /* If the class doesn't have an attribute, nothing more to do. */
4887 /* Any method that does not yet have a tm attribute inherits
4888 the one from the class. */
4893 }
4895 /* Returns true if FN is a default constructor. */
4897 bool
4899 {
4902 }
4904 /* Returns true iff class T has a user-defined constructor that can be called
4905 with more than zero arguments. */
4907 bool
4909 {
4914 {
4921 }
4924 }
4926 /* Returns the defaulted constructor if T has one. Otherwise, returns
4927 NULL_TREE. */
4929 tree
4931 {
4936 {
4942 }
4945 }
4947 /* Returns true iff FN is a user-provided function, i.e. user-declared
4948 and not defaulted at its first declaration. */
4950 bool
4952 {
4955 else
4959 }
4961 /* Returns true iff class T has a user-provided constructor. */
4963 bool
4965 {
4977 }
4979 /* Returns true iff class T has a user-provided or explicit constructor. */
4981 bool
4983 {
4991 {
4995 }
4998 }
5000 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5001 declared or explicitly defaulted in the class body) default
5002 constructor. */
5004 bool
5006 {
5013 {
5019 }
5022 }
5024 /* TYPE is being used as a virtual base, and has a non-trivial move
5025 assignment. Return true if this is due to there being a user-provided
5026 move assignment in TYPE or one of its subobjects; if there isn't, then
5027 multiple move assignment can't cause any harm. */
5029 bool
5031 {
5032 /* Does the type itself have a user-provided move assignment operator? */
5040 /* Do any of its bases? */
5042 tree base_binfo;
5047 /* Or non-static data members? */
5049 {
5054 }
5056 /* Seems not. */
5058 }
5060 /* If default-initialization leaves part of TYPE uninitialized, returns
5061 a DECL for the field or TYPE itself (DR 253). */
5063 tree
5065 {
5076 {
5080 }
5085 {
5089 }
5092 }
5094 /* Returns true iff for class T, a trivial synthesized default constructor
5095 would be constexpr. */
5097 bool
5099 {
5100 /* A defaulted trivial default constructor is constexpr
5101 if there is nothing to initialize. */
5104 }
5106 /* Returns true iff class T has a constexpr default constructor. */
5108 bool
5110 {
5111 tree fns;
5114 {
5115 /* The caller should have stripped an enclosing array. */
5118 }
5120 {
5123 /* Non-trivial, we need to check subobject constructors. */
5125 }
5128 }
5130 /* Returns true iff class T has a constexpr default constructor or has an
5131 implicitly declared default constructor that we can't tell if it's constexpr
5132 without forcing a lazy declaration (which might cause undesired
5133 instantiations). */
5135 bool
5137 {
5140 /* Assume it's constexpr. */
5143 }
5145 /* Returns true iff class TYPE has a virtual destructor. */
5147 bool
5149 {
5150 tree dtor;
5158 }
5160 /* Returns true iff T, a class, has a move-assignment or
5161 move-constructor. Does not lazily declare either.
5162 If USER_P is false, any move function will do. If it is true, the
5163 move function must be user-declared.
5165 Note that user-declared here is different from "user-provided",
5166 which doesn't include functions that are defaulted in the
5167 class. */
5169 bool
5171 {
5189 }
5191 /* Nonzero if we need to build up a constructor call when initializing an
5192 object of this class, either because it has a user-declared constructor
5193 or because it doesn't have a default constructor (so we need to give an
5194 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5195 what you care about is whether or not an object can be produced by a
5196 constructor (e.g. so we don't set TREE_READONLY on const variables of
5197 such type); use this function when what you care about is whether or not
5198 to try to call a constructor to create an object. The latter case is
5199 the former plus some cases of constructors that cannot be called. */
5201 bool
5203 {
5204 tree inner;
5214 /* A user-declared constructor might be private, and a constructor might
5215 be trivial but deleted. */
5218 {
5223 }
5225 }
5227 /* Like type_build_ctor_call, but for destructors. */
5229 bool
5231 {
5232 tree inner;
5241 /* A user-declared destructor might be private, and a destructor might
5242 be trivial but deleted. */
5245 {
5250 }
5252 }
5254 /* Remove all zero-width bit-fields from T. */
5256 static void
5258 {
5263 {
5266 /* We should not be confused by the fact that grokbitfield
5267 temporarily sets the width of the bit field into
5268 DECL_BIT_FIELD_REPRESENTATIVE (*fieldsp).
5269 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5270 to that width. */
5274 else
5276 }
5277 }
5279 /* Returns TRUE iff we need a cookie when dynamically allocating an
5280 array whose elements have the indicated class TYPE. */
5282 static bool
5284 {
5285 tree fns;
5290 /* If there's a non-trivial destructor, we need a cookie. In order
5291 to iterate through the array calling the destructor for each
5292 element, we'll have to know how many elements there are. */
5296 /* If the usual deallocation function is a two-argument whose second
5297 argument is of type `size_t', then we have to pass the size of
5298 the array to the deallocation function, so we will need to store
5299 a cookie. */
5303 /* If there are no `operator []' members, or the lookup is
5304 ambiguous, then we don't need a cookie. */
5307 /* Loop through all of the functions. */
5309 {
5312 /* See if this function is a one-argument delete function. If
5313 it is, then it will be the usual deallocation function. */
5317 /* Do not consider this function if its second argument is an
5318 ellipsis. */
5321 /* Otherwise, if we have a two-argument function and the second
5322 argument is `size_t', it will be the usual deallocation
5323 function -- unless there is one-argument function, too. */
5327 }
5330 }
5332 /* Finish computing the `literal type' property of class type T.
5334 At this point, we have already processed base classes and
5335 non-static data members. We need to check whether the copy
5336 constructor is trivial, the destructor is trivial, and there
5337 is a trivial default constructor or at least one constexpr
5338 constructor other than the copy constructor. */
5340 static void
5342 {
5343 tree fn;
5355 /* C++14 DR 1684 removed this restriction. */
5363 {
5367 "enclosing class of %<constexpr%> non-static member "
5370 }
5371 }
5373 /* T is a non-literal type used in a context which requires a constant
5374 expression. Explain why it isn't literal. */
5376 void
5378 {
5388 /* Already explained. */
5394 " %qT is a closure type, which is only literal in "
5402 {
5404 " %q+T is not an aggregate, does not have a trivial "
5405 "default constructor, and has no %<constexpr%> constructor that "
5408 /* Note that we can't simply call locate_ctor because when the
5409 constructor is deleted it just returns NULL_TREE. */
5411 {
5418 {
5421 else
5424 }
5425 }
5426 }
5427 else
5428 {
5432 {
5435 {
5441 }
5442 }
5444 {
5445 tree ftype;
5450 {
5453 field);
5456 }
5460 }
5461 }
5462 }
5464 /* Check the validity of the bases and members declared in T. Add any
5465 implicitly-generated functions (like copy-constructors and
5466 assignment operators). Compute various flag bits (like
5467 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5468 level: i.e., independently of the ABI in use. */
5470 static void
5472 {
5473 /* Nonzero if the implicitly generated copy constructor should take
5474 a non-const reference argument. */
5476 /* Nonzero if the implicitly generated assignment operator
5477 should take a non-const reference argument. */
5479 tree access_decls;
5482 tree fn;
5484 /* By default, we use const reference arguments and generate default
5485 constructors. */
5489 /* Check all the base-classes and set FMEM members to point to arrays
5490 of potential interest. */
5493 /* Deduce noexcept on destructor. This needs to happen after we've set
5494 triviality flags appropriately for our bases. */
5499 /* Check all the method declarations. */
5502 /* Save the initial values of these flags which only indicate whether
5503 or not the class has user-provided functions. As we analyze the
5504 bases and members we can set these flags for other reasons. */
5508 /* Check all the data member declarations. We cannot call
5509 check_field_decls until we have called check_bases check_methods,
5510 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5511 being set appropriately. */
5516 /* A nearly-empty class has to be vptr-containing; a nearly empty
5517 class contains just a vptr. */
5521 /* Do some bookkeeping that will guide the generation of implicitly
5522 declared member functions. */
5525 /* We need to call a constructor for this class if it has a
5526 user-provided constructor, or if the default constructor is going
5527 to initialize the vptr. (This is not an if-and-only-if;
5528 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5529 themselves need constructing.) */
5532 /* [dcl.init.aggr]
5534 An aggregate is an array or a class with no user-provided
5535 constructors ... and no virtual functions.
5537 Again, other conditions for being an aggregate are checked
5538 elsewhere. */
5542 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5543 retain the old definition internally for ABI reasons. */
5552 /* If the only explicitly declared default constructor is user-provided,
5553 set TYPE_HAS_COMPLEX_DFLT. */
5559 /* Warn if a public base of a polymorphic type has an accessible
5560 non-virtual destructor. It is only now that we know the class is
5561 polymorphic. Although a polymorphic base will have a already
5562 been diagnosed during its definition, we warn on use too. */
5564 {
5567 tree base_binfo;
5571 {
5579 basetype);
5580 }
5581 }
5583 /* If the class has no user-declared constructor, but does have
5584 non-static const or reference data members that can never be
5585 initialized, issue a warning. */
5587 /* Classes with user-declared constructors are presumed to
5588 initialize these members. */
5590 /* Aggregates can be initialized with brace-enclosed
5591 initializers. */
5593 {
5594 tree field;
5597 {
5598 tree type;
5615 }
5616 }
5618 /* Synthesize any needed methods. */
5620 cant_have_const_ctor,
5621 no_const_asn_ref);
5623 /* Check defaulted declarations here so we have cant_have_const_ctor
5624 and don't need to worry about clones. */
5629 {
5632 {
5633 bool imp_const_p
5639 /* If the function is defaulted outside the class, we just
5640 give the synthesis error. */
5643 }
5645 }
5648 {
5649 /* "This class type is not an aggregate." */
5651 }
5653 /* Compute the 'literal type' property before we
5654 do anything with non-static member functions. */
5657 /* Create the in-charge and not-in-charge variants of constructors
5658 and destructors. */
5661 /* Process the using-declarations. */
5665 /* Figure out whether or not we will need a cookie when dynamically
5666 allocating an array of this type. */
5669 }
5671 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5672 accordingly. If a new vfield was created (because T doesn't have a
5673 primary base class), then the newly created field is returned. It
5674 is not added to the TYPE_FIELDS list; it is the caller's
5675 responsibility to do that. Accumulate declared virtual functions
5676 on VIRTUALS_P. */
5678 static tree
5680 {
5681 tree fn;
5683 /* Collect the virtual functions declared in T. */
5688 {
5697 }
5699 /* If we couldn't find an appropriate base class, create a new field
5700 here. Even if there weren't any new virtual functions, we might need a
5701 new virtual function table if we're supposed to include vptrs in
5702 all classes that need them. */
5704 {
5705 /* We build this decl with vtbl_ptr_type_node, which is a
5706 `vtable_entry_type*'. It might seem more precise to use
5707 `vtable_entry_type (*)[N]' where N is the number of virtual
5708 functions. However, that would require the vtable pointer in
5709 base classes to have a different type than the vtable pointer
5710 in derived classes. We could make that happen, but that
5711 still wouldn't solve all the problems. In particular, the
5712 type-based alias analysis code would decide that assignments
5713 to the base class vtable pointer can't alias assignments to
5714 the derived class vtable pointer, since they have different
5715 types. Thus, in a derived class destructor, where the base
5716 class constructor was inlined, we could generate bad code for
5717 setting up the vtable pointer.
5719 Therefore, we use one type for all vtable pointers. We still
5720 use a type-correct type; it's just doesn't indicate the array
5721 bounds. That's better than using `void*' or some such; it's
5722 cleaner, and it let's the alias analysis code know that these
5723 stores cannot alias stores to void*! */
5724 tree field;
5737 /* This class is non-empty. */
5741 }
5744 }
5746 /* Add OFFSET to all base types of BINFO which is a base in the
5747 hierarchy dominated by T.
5749 OFFSET, which is a type offset, is number of bytes. */
5751 static void
5753 {
5755 tree primary_binfo;
5756 tree base_binfo;
5758 /* Update BINFO's offset. */
5763 offset));
5765 /* Find the primary base class. */
5771 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5772 downwards. */
5774 {
5775 /* Don't do the primary base twice. */
5783 }
5784 }
5786 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5787 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5788 empty subobjects of T. */
5790 static void
5792 {
5793 tree vbase;
5800 /* Find the last field. The artificial fields created for virtual
5801 bases will go after the last extant field to date. */
5806 /* Go through the virtual bases, allocating space for each virtual
5807 base that is not already a primary base class. These are
5808 allocated in inheritance graph order. */
5810 {
5815 {
5816 /* This virtual base is not a primary base of any class in the
5817 hierarchy, so we have to add space for it. */
5820 }
5821 }
5822 }
5824 /* Returns the offset of the byte just past the end of the base class
5825 BINFO. */
5827 static tree
5829 {
5830 tree size;
5835 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5836 allocate some space for it. It cannot have virtual bases, so
5837 TYPE_SIZE_UNIT is fine. */
5839 else
5843 }
5845 /* Returns the offset of the byte just past the end of the base class
5846 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
5847 only non-virtual bases are included. */
5849 static tree
5851 {
5854 tree binfo;
5855 tree base_binfo;
5856 tree offset;
5861 {
5871 }
5876 {
5880 }
5883 }
5885 /* Warn about bases of T that are inaccessible because they are
5886 ambiguous. For example:
5888 struct S {};
5889 struct T : public S {};
5890 struct U : public S, public T {};
5892 Here, `(S*) new U' is not allowed because there are two `S'
5893 subobjects of U. */
5895 static void
5897 {
5900 tree basetype;
5901 tree binfo;
5902 tree base_binfo;
5904 /* If there are no repeated bases, nothing can be ambiguous. */
5908 /* Check direct bases. */
5911 {
5917 }
5919 /* Check for ambiguous virtual bases. */
5923 {
5929 }
5930 }
5932 /* Compare two INTEGER_CSTs K1 and K2. */
5934 static int
5936 {
5938 }
5940 /* Increase the size indicated in RLI to account for empty classes
5941 that are "off the end" of the class. */
5943 static void
5945 {
5946 tree eoc;
5947 tree rli_size;
5949 /* It might be the case that we grew the class to allocate a
5950 zero-sized base class. That won't be reflected in RLI, yet,
5951 because we are willing to overlay multiple bases at the same
5952 offset. However, now we need to make sure that RLI is big enough
5953 to reflect the entire class. */
5958 {
5959 /* The size should have been rounded to a whole byte. */
5962 rli->bitpos
5971 }
5972 }
5974 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
5975 BINFO_OFFSETs for all of the base-classes. Position the vtable
5976 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
5978 static void
5980 {
5981 tree non_static_data_members;
5982 tree field;
5983 tree vptr;
5984 record_layout_info rli;
5985 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
5986 types that appear at that offset. */
5987 splay_tree empty_base_offsets;
5988 /* True if the last field laid out was a bit-field. */
5990 /* The location at which the next field should be inserted. */
5993 /* Keep track of the first non-static data member. */
5996 /* Start laying out the record. */
5999 /* Mark all the primary bases in the hierarchy. */
6002 /* Create a pointer to our virtual function table. */
6005 /* The vptr is always the first thing in the class. */
6007 {
6012 }
6013 else
6016 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6021 /* Layout the non-static data members. */
6023 {
6024 tree type;
6025 tree padding;
6027 /* We still pass things that aren't non-static data members to
6028 the back end, in case it wants to do something with them. */
6030 {
6032 /* If the static data member has incomplete type, keep track
6033 of it so that it can be completed later. (The handling
6034 of pending statics in finish_record_layout is
6035 insufficient; consider:
6037 struct S1;
6038 struct S2 { static S1 s1; };
6040 At this point, finish_record_layout will be called, but
6041 S1 is still incomplete.) */
6043 {
6045 /* The visibility of static data members is determined
6046 at their point of declaration, not their point of
6047 definition. */
6049 }
6051 }
6059 /* If this field is a bit-field whose width is greater than its
6060 type, then there are some special rules for allocating
6061 it. */
6064 {
6066 /* We must allocate the bits as if suitably aligned for the
6067 longest integer type that fits in this many bits. Then,
6068 we are supposed to use the left over bits as additional
6069 padding. */
6071 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6079 {
6081 /* Too big, so our current guess is what we want. */
6083 /* Not bigger than limit, ok */
6085 }
6087 /* Figure out how much additional padding is required. */
6089 /* In a union, the padding field must have the full width
6090 of the bit-field; all fields start at offset zero. */
6092 else
6099 /* An unnamed bitfield does not normally affect the
6100 alignment of the containing class on a target where
6101 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6102 make any exceptions for unnamed bitfields when the
6103 bitfields are longer than their types. Therefore, we
6104 temporarily give the field a name. */
6106 {
6109 }
6115 empty_base_offsets);
6118 /* Now that layout has been performed, set the size of the
6119 field to the size of its declared type; the rest of the
6120 field is effectively invisible. */
6122 /* We must also reset the DECL_MODE of the field. */
6124 }
6125 else
6127 empty_base_offsets);
6129 /* Remember the location of any empty classes in FIELD. */
6132 empty_base_offsets,
6135 /* If a bit-field does not immediately follow another bit-field,
6136 and yet it starts in the middle of a byte, we have failed to
6137 comply with the ABI. */
6140 /* The TREE_NO_WARNING flag gets set by Objective-C when
6141 laying out an Objective-C class. The ObjC ABI differs
6142 from the C++ ABI, and so we do not want a warning
6143 here. */
6145 && !last_field_was_bitfield
6148 bitsize_unit_node)))
6150 "offset of %qD is not ABI-compliant and may "
6153 /* The middle end uses the type of expressions to determine the
6154 possible range of expression values. In order to optimize
6155 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6156 must be made aware of the width of "i", via its type.
6158 Because C++ does not have integer types of arbitrary width,
6159 we must (for the purposes of the front end) convert from the
6160 type assigned here to the declared type of the bitfield
6161 whenever a bitfield expression is used as an rvalue.
6162 Similarly, when assigning a value to a bitfield, the value
6163 must be converted to the type given the bitfield here. */
6165 {
6170 {
6177 }
6178 }
6180 /* If we needed additional padding after this field, add it
6181 now. */
6183 {
6184 tree padding_field;
6187 FIELD_DECL,
6188 NULL_TREE,
6189 char_type_node);
6197 NULL_TREE,
6198 empty_base_offsets);
6199 }
6202 }
6205 {
6206 /* Make sure that we are on a byte boundary so that the size of
6207 the class without virtual bases will always be a round number
6208 of bytes. */
6211 }
6213 /* Delete all zero-width bit-fields from the list of fields. Now
6214 that the type is laid out they are no longer important. */
6218 {
6219 /* T needs a different layout as a base (eliding virtual bases
6220 or whatever). Create that version. */
6223 /* If the ABI version is not at least two, and the last
6224 field was a bit-field, RLI may not be on a byte
6225 boundary. In particular, rli_size_unit_so_far might
6226 indicate the last complete byte, while rli_size_so_far
6227 indicates the total number of bits used. Therefore,
6228 rli_size_so_far, rather than rli_size_unit_so_far, is
6229 used to compute TYPE_SIZE_UNIT. */
6237 eoc);
6247 /* Copy the non-static data members of T. This will include its
6248 direct non-virtual bases & vtable. */
6252 {
6256 }
6259 /* We use the base type for trivial assignments, and hence it
6260 needs a mode. */
6265 /* Record the base version of the type. */
6267 }
6268 else
6271 /* Every empty class contains an empty class. */
6275 /* Set the TYPE_DECL for this type to contain the right
6276 value for DECL_OFFSET, so that we can use it as part
6277 of a COMPONENT_REF for multiple inheritance. */
6280 /* Now fix up any virtual base class types that we left lying
6281 around. We must get these done before we try to lay out the
6282 virtual function table. As a side-effect, this will remove the
6283 base subobject fields. */
6286 /* Make sure that empty classes are reflected in RLI at this
6287 point. */
6290 /* Make sure not to create any structures with zero size. */
6296 /* If this is a non-POD, declaring it packed makes a difference to how it
6297 can be used as a field; don't let finalize_record_size undo it. */
6301 /* Let the back end lay out the type. */
6310 /* Warn about bases that can't be talked about due to ambiguity. */
6313 /* Now that we're done with layout, give the base fields the real types. */
6318 /* Clean up. */
6325 }
6327 /* Determine the "key method" for the class type indicated by TYPE,
6328 and set CLASSTYPE_KEY_METHOD accordingly. */
6330 void
6332 {
6333 tree method;
6340 /* The key method is the first non-pure virtual function that is not
6341 inline at the point of class definition. On some targets the
6342 key function may not be inline; those targets should not call
6343 this function until the end of the translation unit. */
6349 {
6352 }
6355 }
6357 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6358 class data member of non-zero size, otherwise false. */
6362 {
6370 {
6374 }
6377 }
6379 /* Used by find_flexarrays and related functions. */
6381 struct flexmems_t
6382 {
6383 /* The first flexible array member or non-zero array member found
6384 in the order of layout. */
6385 tree array;
6386 /* First non-static non-empty data member in the class or its bases. */
6387 tree first;
6388 /* The first non-static non-empty data member following either
6389 the flexible array member, if found, or the zero-length array member
6390 otherwise. AFTER[1] refers to the first such data member of a union
6391 of which the struct containing the flexible array member or zero-length
6392 array is a member, or NULL when no such union exists. This element is
6393 only used during searching, not for diagnosing problems. AFTER[0]
6394 refers to the first such data member that is not a member of such
6395 a union. */
6398 /* Refers to a struct (not union) in which the struct of which the flexible
6399 array is member is defined. Used to diagnose strictly (according to C)
6400 invalid uses of the latter structs. */
6401 tree enclosing;
6402 };
6404 /* Find either the first flexible array member or the first zero-length
6405 array, in that order of preference, among members of class T (but not
6406 its base classes), and set members of FMEM accordingly.
6407 BASE_P is true if T is a base class of another class.
6408 PUN is set to the outermost union in which the flexible array member
6409 (or zero-length array) is defined if one such union exists, otherwise
6410 to NULL.
6411 Similarly, PSTR is set to a data member of the outermost struct of
6412 which the flexible array is a member if one such struct exists,
6413 otherwise to NULL. */
6415 static void
6419 {
6420 /* Set the "pointer" to the outermost enclosing union if not set
6421 yet and maintain it for the remainder of the recursion. */
6426 {
6430 /* Is FLD a typedef for an anonymous struct? */
6432 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6433 handled elsewhere so that errors like the following are detected
6434 as well:
6435 typedef struct { int i, a[], j; } S; // bug c++/72753
6436 S s [2]; // bug c++/68489
6437 */
6442 {
6443 /* Check the nested unnamed type referenced via a typedef
6444 independently of FMEM (since it's not a data member of
6445 the enclosing class). */
6448 }
6450 /* Skip anything that's GCC-generated or not a (non-static) data
6451 member. */
6455 /* Type of the member. */
6460 /* Determine the type of the array element or object referenced
6461 by the member so that it can be checked for flexible array
6462 members if it hasn't been yet. */
6470 {
6472 {
6473 /* Once the member after the flexible array has been found
6474 we're done. */
6477 }
6480 {
6481 /* Descend into the non-static member struct or union and try
6482 to find a flexible array member or zero-length array among
6483 its members. This is only necessary for anonymous types
6484 and types in whose context the current type T has not been
6485 defined (the latter must not be checked again because they
6486 are already in the process of being checked by one of the
6487 recursive calls). */
6492 /* If this member isn't anonymous and a prior non-flexible array
6493 member has been seen in one of the enclosing structs, clear
6494 the FIRST member since it doesn't contribute to the flexible
6495 array struct's members. */
6506 {
6507 /* Restore the FIRST member reset above if no flexible
6508 array member has been found in this member's struct. */
6510 }
6512 /* If the member struct contains the first flexible array
6513 member, or if this member is a base class, continue to
6514 the next member and avoid setting the FMEM->NEXT pointer
6515 to point to it. */
6518 }
6519 }
6522 {
6523 /* Remember the first non-static data member. */
6527 /* Remember the first non-static data member after the flexible
6528 array member, if one has been found, or the zero-length array
6529 if it has been found. */
6532 }
6534 /* Skip non-arrays. */
6538 /* Determine the upper bound of the array if it has one. */
6540 {
6542 {
6543 /* Make a record of the zero-length array if either one
6544 such field or a flexible array member has been seen to
6545 handle the pathological and unlikely case of multiple
6546 such members. */
6549 }
6551 {
6552 /* Remember the first zero-length array unless a flexible array
6553 member has already been seen. */
6556 }
6557 }
6558 else
6559 {
6560 /* Flexible array members have no upper bound. */
6562 {
6564 {
6565 /* Replace the zero-length array if it's been stored and
6566 reset the after pointer. */
6570 }
6572 /* Make a record of another flexible array member. */
6574 }
6575 else
6576 {
6579 }
6580 }
6581 }
6582 }
6584 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6585 a flexible array member (or the zero-length array extension). */
6587 static void
6589 {
6601 }
6603 /* Issue diagnostics for invalid flexible array members or zero-length
6604 arrays that are not the last elements of the containing class or its
6605 base classes or that are its sole members. */
6607 static void
6609 {
6614 {
6617 }
6619 /* Has a diagnostic been issued? */
6625 {
6632 {
6636 {
6639 }
6640 }
6641 }
6642 else
6643 {
6650 {
6656 /* In the unlikely event that the member following the flexible
6657 array member is declared in a different class, or the member
6658 overlaps another member of a common union, point to it.
6659 Otherwise it should be obvious. */
6663 {
6668 }
6669 }
6670 }
6674 }
6677 /* Recursively check to make sure that any flexible array or zero-length
6678 array members of class T or its bases are valid (i.e., not the sole
6679 non-static data member of T and, if one exists, that it is the last
6680 non-static data member of T and its base classes. FMEM is expected
6681 to be initially null and is used internally by recursive calls to
6682 the function. Issue the appropriate diagnostics for the array member
6683 that fails the checks. */
6685 static void
6688 {
6689 /* Initialize the result of a search for flexible array and zero-length
6690 array members. Avoid doing any work if the most interesting FMEM data
6691 have already been populated. */
6700 /* Recursively check the primary base class first. */
6702 {
6705 }
6707 /* Recursively check the base classes. */
6710 {
6713 /* The primary base class was already checked above. */
6717 /* Virtual base classes are at the end. */
6721 /* Check the base class. */
6723 }
6726 {
6727 /* Check virtual base classes only once per derived class.
6728 I.e., this check is not performed recursively for base
6729 classes. */
6731 tree base_binfo;
6735 {
6736 /* Check the virtual base class. */
6740 }
6741 }
6743 /* Is the type unnamed (and therefore a member of it potentially
6744 an anonymous struct or union)? */
6747 /* Search the members of the current (possibly derived) class, skipping
6748 unnamed structs and unions since those could be anonymous. */
6753 {
6754 /* Issue diagnostics for invalid flexible and zero-length array
6755 members found in base classes or among the members of the current
6756 class. Ignore anonymous structs and unions whose members are
6757 considered to be members of the enclosing class and thus will
6758 be diagnosed when checking it. */
6760 }
6761 }
6763 /* Perform processing required when the definition of T (a class type)
6764 is complete. Diagnose invalid definitions of flexible array members
6765 and zero-size arrays. */
6767 void
6769 {
6770 tree x;
6771 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6775 {
6780 }
6782 /* If this type was previously laid out as a forward reference,
6783 make sure we lay it out again. */
6787 /* Make assumptions about the class; we'll reset the flags if
6788 necessary. */
6794 /* Do end-of-class semantic processing: checking the validity of the
6795 bases and members and add implicitly generated methods. */
6798 /* Find the key method. */
6800 {
6801 /* The Itanium C++ ABI permits the key method to be chosen when
6802 the class is defined -- even though the key method so
6803 selected may later turn out to be an inline function. On
6804 some systems (such as ARM Symbian OS) the key method cannot
6805 be determined until the end of the translation unit. On such
6806 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6807 will cause the class to be added to KEYED_CLASSES. Then, in
6808 finish_file we will determine the key method. */
6812 /* If a polymorphic class has no key method, we may emit the vtable
6813 in every translation unit where the class definition appears. If
6814 we're devirtualizing, we can look into the vtable even if we
6815 aren't emitting it. */
6818 }
6820 /* Layout the class itself. */
6822 /* COMPLETE_TYPE_P is now true. */
6826 /* With the layout complete, check for flexible array members and
6827 zero-length arrays that might overlap other members in the final
6828 layout. */
6833 /* If necessary, create the primary vtable for this class. */
6835 {
6836 /* We must enter these virtuals into the table. */
6840 /* Here we know enough to change the type of our virtual
6841 function table, but we will wait until later this function. */
6844 /* If we're warning about ABI tags, check the types of the new
6845 virtual functions. */
6849 }
6852 {
6854 tree fn;
6861 /* Add entries for virtual functions introduced by this class. */
6865 /* Set DECL_VINDEX for all functions declared in this class. */
6867 fn;
6869 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6871 {
6875 /* A thunk. We should never be calling this entry directly
6876 from this vtable -- we'd use the entry for the non
6877 thunk base function. */
6881 }
6882 }
6890 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
6891 for any static member objects of the type we're working on. */
6900 /* Complain if one of the field types requires lower visibility. */
6903 /* Make the rtl for any new vtables we have created, and unmark
6904 the base types we marked. */
6907 /* Build the VTT for T. */
6914 "%q#T has virtual functions and accessible"
6922 /* Class layout, assignment of virtual table slots, etc., is now
6923 complete. Give the back end a chance to tweak the visibility of
6924 the class or perform any other required target modifications. */
6934 /* Finish debugging output for this type. */
6938 {
6941 {
6944 }
6946 {
6949 else
6950 {
6953 }
6955 }
6957 {
6959 "the type of the first field has a different ABI from the "
6962 }
6963 }
6964 }
6966 /* When T was built up, the member declarations were added in reverse
6967 order. Rearrange them to declaration order. */
6969 void
6971 {
6972 tree next;
6973 tree prev;
6974 tree x;
6976 /* The following lists are all in reverse order. Put them in
6977 declaration order now. */
6980 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
6981 order, so we can't just use nreverse. Due to stat_hack
6982 chicanery in finish_member_declaration. */
6987 {
6991 }
6994 {
6997 }
6998 }
7000 tree
7002 {
7005 /* Now that we've got all the field declarations, reverse everything
7006 as necessary. */
7012 /* Nadger the current location so that diagnostics point to the start of
7013 the struct, not the end. */
7017 {
7018 tree x;
7020 /* We need to add the target functions of USING_DECLS, so that
7021 they can be found when the using declaration is not
7022 instantiated yet. */
7025 {
7030 }
7036 /* COMPLETE_TYPE_P is now true. */
7040 /* We need to emit an error message if this type was used as a parameter
7041 and it is an abstract type, even if it is a template. We construct
7042 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7043 account and we call complete_vars with this type, which will check
7044 the PARM_DECLS. Note that while the type is being defined,
7045 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7046 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7053 /* Remember current #pragma pack value. */
7056 /* Fix up any variants we've already built. */
7058 {
7062 }
7063 }
7064 else
7066 /* COMPLETE_TYPE_P is now true. */
7071 {
7072 /* People keep complaining that the compiler crashes on an invalid
7073 definition of initializer_list, so I guess we should explicitly
7074 reject it. What the compiler internals care about is that it's a
7075 template and has a pointer field followed by size_type field. */
7078 {
7081 {
7085 }
7086 }
7090 }
7098 else
7102 /* Lambdas are defined by the LAMBDA_EXPR. */
7107 }
7108 \f
7109 /* Hash table to avoid endless recursion when handling references. */
7112 /* Return the dynamic type of INSTANCE, if known.
7113 Used to determine whether the virtual function table is needed
7114 or not.
7116 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7117 of our knowledge of its type. *NONNULL should be initialized
7118 before this function is called. */
7120 static tree
7122 {
7123 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7126 {
7130 else
7134 /* This is a call to a constructor, hence it's never zero. */
7137 {
7141 }
7145 /* This is a call to a constructor, hence it's never zero. */
7147 {
7151 }
7160 /* Propagate nonnull. */
7165 CASE_CONVERT:
7171 {
7172 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7173 with a real object -- given &p->f, p can still be null. */
7175 /* ??? Probably should check DECL_WEAK here. */
7178 }
7182 /* If this component is really a base class reference, then the field
7183 itself isn't definitive. */
7192 {
7196 }
7197 /* fall through. */
7202 {
7206 }
7208 {
7212 /* if we're in a ctor or dtor, we know our type. If
7213 current_class_ptr is set but we aren't in a function, we're in
7214 an NSDMI (and therefore a constructor). */
7219 {
7223 }
7224 }
7226 {
7227 /* We only need one hash table because it is always left empty. */
7229 fixed_type_or_null_ref_ht
7232 /* Reference variables should be references to objects. */
7236 /* Enter the INSTANCE in a table to prevent recursion; a
7237 variable's initializer may refer to the variable
7238 itself. */
7243 {
7244 tree type;
7253 }
7254 }
7259 }
7260 #undef RECUR
7261 }
7263 /* Return nonzero if the dynamic type of INSTANCE is known, and
7264 equivalent to the static type. We also handle the case where
7265 INSTANCE is really a pointer. Return negative if this is a
7266 ctor/dtor. There the dynamic type is known, but this might not be
7267 the most derived base of the original object, and hence virtual
7268 bases may not be laid out according to this type.
7270 Used to determine whether the virtual function table is needed
7271 or not.
7273 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7274 of our knowledge of its type. *NONNULL should be initialized
7275 before this function is called. */
7277 int
7279 {
7282 tree fixed;
7284 /* processing_template_decl can be false in a template if we're in
7285 instantiate_non_dependent_expr, but we still want to suppress
7286 this check. */
7288 {
7289 /* In a template we only care about the type of the result. */
7293 }
7303 }
7305 \f
7306 void
7308 {
7311 current_class_stack
7319 }
7321 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7323 static void
7325 {
7326 tree type;
7328 /* We are re-entering the same class we just left, so we don't
7329 have to search the whole inheritance matrix to find all the
7330 decls to bind again. Instead, we install the cached
7331 class_shadowed list and walk through it binding names. */
7334 /* Restore IDENTIFIER_TYPE_VALUE. */
7336 type;
7339 }
7341 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7342 appropriate for TYPE.
7344 So that we may avoid calls to lookup_name, we cache the _TYPE
7345 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7347 For multiple inheritance, we perform a two-pass depth-first search
7348 of the type lattice. */
7350 void
7352 {
7353 class_stack_node_t csn;
7357 /* Make sure there is enough room for the new entry on the stack. */
7359 {
7361 current_class_stack
7363 current_class_stack_size);
7364 }
7366 /* Insert a new entry on the class stack. */
7373 current_class_depth++;
7375 /* Now set up the new type. */
7381 /* By default, things in classes are private, while things in
7382 structures or unions are public. */
7384 ? access_private_node
7390 {
7391 /* Forcibly remove any old class remnants. */
7393 }
7399 else
7401 }
7403 /* When we exit a toplevel class scope, we save its binding level so
7404 that we can restore it quickly. Here, we've entered some other
7405 class, so we must invalidate our cache. */
7407 void
7409 {
7411 }
7413 /* Get out of the current class scope. If we were in a class scope
7414 previously, that is the one popped to. */
7416 void
7418 {
7421 current_class_depth--;
7427 }
7429 /* Mark the top of the class stack as hidden. */
7431 void
7433 {
7436 }
7438 /* Mark the top of the class stack as un-hidden. */
7440 void
7442 {
7445 }
7447 /* Returns 1 if the class type currently being defined is either T or
7448 a nested type of T. Returns the type from the current_class_stack,
7449 which might be equivalent to but not equal to T in case of
7450 constrained partial specializations. */
7452 tree
7454 {
7462 /* We start looking from 1 because entry 0 is from global scope,
7463 and has no type. */
7465 {
7466 tree c;
7469 else
7470 {
7474 }
7479 }
7481 }
7483 /* If either current_class_type or one of its enclosing classes are derived
7484 from T, return the appropriate type. Used to determine how we found
7485 something via unqualified lookup. */
7487 tree
7489 {
7492 /* The bases of a dependent type are unknown. */
7503 {
7508 }
7511 }
7513 /* Return the outermost enclosing class type that is still open, or
7514 NULL_TREE. */
7516 tree
7518 {
7525 {
7532 }
7534 }
7536 /* Returns the innermost class type which is not a lambda closure type. */
7538 tree
7540 {
7545 }
7547 /* When entering a class scope, all enclosing class scopes' names with
7548 static meaning (static variables, static functions, types and
7549 enumerators) have to be visible. This recursive function calls
7550 pushclass for all enclosing class contexts until global or a local
7551 scope is reached. TYPE is the enclosed class. */
7553 void
7555 {
7556 /* A namespace might be passed in error cases, like A::B:C. */
7564 }
7566 /* Undoes a push_nested_class call. */
7568 void
7570 {
7576 }
7578 /* Returns the number of extern "LANG" blocks we are nested within. */
7580 int
7582 {
7584 }
7586 /* Set global variables CURRENT_LANG_NAME to appropriate value
7587 so that behavior of name-mangling machinery is correct. */
7589 void
7591 {
7598 else
7600 }
7602 /* Get out of the current language scope. */
7604 void
7606 {
7608 }
7609 \f
7610 /* Type instantiation routines. */
7612 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7613 matches the TARGET_TYPE. If there is no satisfactory match, return
7614 error_mark_node, and issue an error & warning messages under
7615 control of FLAGS. Permit pointers to member function if FLAGS
7616 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7617 a template-id, and EXPLICIT_TARGS are the explicitly provided
7618 template arguments.
7620 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7621 is the base path used to reference those member functions. If
7622 the address is resolved to a member function, access checks will be
7623 performed and errors issued if appropriate. */
7625 static tree
7627 tree overload,
7628 tsubst_flags_t complain,
7630 tree explicit_targs,
7631 tree access_path)
7632 {
7633 /* Here's what the standard says:
7635 [over.over]
7637 If the name is a function template, template argument deduction
7638 is done, and if the argument deduction succeeds, the deduced
7639 arguments are used to generate a single template function, which
7640 is added to the set of overloaded functions considered.
7642 Non-member functions and static member functions match targets of
7643 type "pointer-to-function" or "reference-to-function." Nonstatic
7644 member functions match targets of type "pointer-to-member
7645 function;" the function type of the pointer to member is used to
7646 select the member function from the set of overloaded member
7647 functions. If a nonstatic member function is selected, the
7648 reference to the overloaded function name is required to have the
7649 form of a pointer to member as described in 5.3.1.
7651 If more than one function is selected, any template functions in
7652 the set are eliminated if the set also contains a non-template
7653 function, and any given template function is eliminated if the
7654 set contains a second template function that is more specialized
7655 than the first according to the partial ordering rules 14.5.5.2.
7656 After such eliminations, if any, there shall remain exactly one
7657 selected function. */
7660 /* We store the matches in a TREE_LIST rooted here. The functions
7661 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7662 interoperability with most_specialized_instantiation. */
7664 tree fn;
7665 tree target_fn_type;
7667 /* By the time we get here, we should be seeing only real
7668 pointer-to-member types, not the internal POINTER_TYPE to
7669 METHOD_TYPE representation. */
7675 /* Check that the TARGET_TYPE is reasonable. */
7680 /* This is OK, too. */
7683 /* This is OK, too. This comes from a conversion to reference
7684 type. */
7686 else
7687 {
7693 }
7695 /* Non-member functions and static member functions match targets of type
7696 "pointer-to-function" or "reference-to-function." Nonstatic member
7697 functions match targets of type "pointer-to-member-function;" the
7698 function type of the pointer to member is used to select the member
7699 function from the set of overloaded member functions.
7701 So figure out the FUNCTION_TYPE that we want to match against. */
7704 /* If we can find a non-template function that matches, we can just
7705 use it. There's no point in generating template instantiations
7706 if we're just going to throw them out anyhow. But, of course, we
7707 can only do this when we don't *need* a template function. */
7710 {
7714 /* We're not looking for templates just yet. */
7718 /* We're looking for a non-static member, and this isn't
7719 one, or vice versa. */
7722 /* In C++17 we need the noexcept-qualifier to compare types. */
7727 /* See if there's a match. */
7732 }
7734 /* Now, if we've already got a match (or matches), there's no need
7735 to proceed to the template functions. But, if we don't have a
7736 match we need to look at them, too. */
7738 {
7739 tree target_arg_types;
7740 tree target_ret_type;
7743 tree arg;
7757 {
7759 tree instantiation;
7760 tree targs;
7763 /* We're only looking for templates. */
7768 /* We're not looking for a non-static member, and this is
7769 one, or vice versa. */
7774 /* If the template has a deduced return type, don't expose it to
7775 template argument deduction. */
7779 /* Try to do argument deduction. */
7786 /* Instantiation failed. */
7789 /* Constraints must be satisfied. This is done before
7790 return type deduction since that instantiates the
7791 function. */
7795 /* And now force instantiation to do return type deduction. */
7797 {
7803 }
7805 /* In C++17 we need the noexcept-qualifier to compare types. */
7809 /* See if there's a match. */
7814 }
7816 /* Now, remove all but the most specialized of the matches. */
7818 {
7823 NULL_TREE,
7824 NULL_TREE);
7825 }
7826 }
7828 /* Now we should have exactly one function in MATCHES. */
7830 {
7831 /* There were *no* matches. */
7833 {
7838 }
7840 }
7842 {
7843 /* There were too many matches. First check if they're all
7844 the same function. */
7849 /* For multi-versioned functions, more than one match is just fine and
7850 decls_match will return false as they are different. */
7858 {
7860 {
7864 /* Since print_candidates expects the functions in the
7865 TREE_VALUE slot, we flip them here. */
7870 }
7873 }
7874 }
7876 /* Good, exactly one match. Now, convert it to the correct type. */
7881 {
7889 {
7892 }
7893 }
7895 /* If a pointer to a function that is multi-versioned is requested, the
7896 pointer to the dispatcher function is returned instead. This works
7897 well because indirectly calling the function will dispatch the right
7898 function version at run-time. */
7900 {
7904 /* Mark all the versions corresponding to the dispatcher as used. */
7907 }
7909 /* If we're doing overload resolution purely for the purpose of
7910 determining conversion sequences, we should not consider the
7911 function used. If this conversion sequence is selected, the
7912 function will be marked as used at this point. */
7914 {
7915 /* Make =delete work with SFINAE. */
7920 }
7922 /* We could not check access to member functions when this
7923 expression was originally created since we did not know at that
7924 time to which function the expression referred. */
7926 {
7929 }
7933 else
7934 {
7935 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
7936 will mark the function as addressed, but here we must do it
7937 explicitly. */
7941 }
7942 }
7944 /* This function will instantiate the type of the expression given in
7945 RHS to match the type of LHSTYPE. If errors exist, then return
7946 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
7947 we complain on errors. If we are not complaining, never modify rhs,
7948 as overload resolution wants to try many possible instantiations, in
7949 the hope that at least one will work.
7951 For non-recursive calls, LHSTYPE should be a function, pointer to
7952 function, or a pointer to member function. */
7954 tree
7956 {
7963 {
7967 }
7970 {
7979 /* Microsoft allows `A::f' to be resolved to a
7980 pointer-to-member. */
7981 ;
7982 else
7983 {
7988 }
7989 }
7992 {
7995 }
7997 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
7998 deduce any type information. */
8000 {
8004 }
8006 /* If we instantiate a template, and it is a A ?: C expression
8007 with omitted B, look through the SAVE_EXPR. */
8011 /* There are only a few kinds of expressions that may have a type
8012 dependent on overload resolution. */
8018 /* This should really only be used when attempting to distinguish
8019 what sort of a pointer to function we have. For now, any
8020 arithmetic operation which is not supported on pointers
8021 is rejected as an error. */
8024 {
8026 {
8032 /* Do not lose object's side effects. */
8036 }
8043 /* This can happen if we are forming a pointer-to-member for a
8044 member template. */
8047 /* Fall through. */
8050 {
8054 return
8058 }
8062 return
8066 access_path);
8069 {
8074 }
8081 }
8083 }
8084 \f
8085 /* Return the name of the virtual function pointer field
8086 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8087 this may have to look back through base types to find the
8088 ultimate field name. (For single inheritance, these could
8089 all be the same name. Who knows for multiple inheritance). */
8091 static tree
8093 {
8099 {
8105 }
8113 }
8115 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8116 according to [class]:
8117 The class-name is also inserted
8118 into the scope of the class itself. For purposes of access checking,
8119 the inserted class name is treated as if it were a public member name. */
8121 void
8123 {
8140 }
8142 /* Returns 1 if TYPE contains only padding bytes. */
8144 int
8146 {
8154 }
8156 /* Returns true if TYPE contains no actual data, just various
8157 possible combinations of empty classes and possibly a vptr. */
8159 bool
8161 {
8163 {
8164 tree field;
8165 tree binfo;
8166 tree base_binfo;
8169 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8170 out, but we'd like to be able to check this before then. */
8181 /* An unnamed bit-field is not a data member. */
8186 }
8191 }
8193 /* Note that NAME was looked up while the current class was being
8194 defined and that the result of that lookup was DECL. */
8196 void
8198 {
8199 splay_tree names_used;
8201 /* If we're not defining a class, there's nothing to do. */
8207 /* If there's already a binding for this NAME, then we don't have
8208 anything to worry about. */
8221 }
8223 /* Note that NAME was declared (as DECL) in the current class. Check
8224 to see that the declaration is valid. */
8226 void
8228 {
8229 splay_tree names_used;
8230 splay_tree_node n;
8232 /* Look to see if we ever used this name. */
8233 names_used
8237 /* The C language allows members to be declared with a type of the same
8238 name, and the C++ standard says this diagnostic is not required. So
8239 allow it in extern "C" blocks unless predantic is specified.
8240 Allow it in all cases if -ms-extensions is specified. */
8246 {
8247 /* [basic.scope.class]
8249 A name N used in a class S shall refer to the same declaration
8250 in its context and when re-evaluated in the completed scope of
8251 S. */
8256 }
8257 }
8259 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8260 Secondary vtables are merged with primary vtables; this function
8261 will return the VAR_DECL for the primary vtable. */
8263 tree
8265 {
8266 tree decl;
8270 {
8273 }
8277 }
8280 /* Returns the binfo for the primary base of BINFO. If the resulting
8281 BINFO is a virtual base, and it is inherited elsewhere in the
8282 hierarchy, then the returned binfo might not be the primary base of
8283 BINFO in the complete object. Check BINFO_PRIMARY_P or
8284 BINFO_LOST_PRIMARY_P to be sure. */
8286 static tree
8288 {
8289 tree primary_base;
8296 }
8298 /* As above, but iterate until we reach the binfo that actually provides the
8299 vptr for BINFO. */
8301 static tree
8303 {
8307 {
8312 }
8314 }
8316 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8317 type. Note that the virtual inheritance might be above or below BINFO in
8318 the hierarchy. */
8320 bool
8322 {
8326 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8327 a morally virtual base. */
8330 }
8332 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8334 static int
8336 {
8340 }
8342 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8343 INDENT should be zero when called from the top level; it is
8344 incremented recursively. IGO indicates the next expected BINFO in
8345 inheritance graph ordering. */
8347 static tree
8349 dump_flags_t flags,
8350 tree binfo,
8351 tree igo,
8353 {
8355 tree base_binfo;
8363 {
8366 }
8381 {
8385 TFF_PLAIN_IDENTIFIER),
8387 }
8389 {
8392 }
8397 {
8401 {
8405 TFF_PLAIN_IDENTIFIER));
8406 }
8408 {
8412 TFF_PLAIN_IDENTIFIER));
8413 }
8415 {
8419 TFF_PLAIN_IDENTIFIER));
8420 }
8422 {
8426 TFF_PLAIN_IDENTIFIER));
8427 }
8431 }
8437 }
8439 /* Dump the BINFO hierarchy for T. */
8441 static void
8443 {
8455 }
8457 /* Debug interface to hierarchy dumping. */
8459 void
8461 {
8463 }
8465 static void
8467 {
8468 dump_flags_t flags;
8470 {
8473 }
8474 }
8476 static void
8478 {
8479 tree value;
8481 HOST_WIDE_INT elt;
8489 TFF_PLAIN_IDENTIFIER));
8496 }
8498 static void
8500 {
8501 dump_flags_t flags;
8508 {
8515 {
8520 }
8524 }
8527 }
8529 static void
8531 {
8532 dump_flags_t flags;
8539 {
8544 }
8547 }
8549 /* Dump a function or thunk and its thunkees. */
8551 static void
8553 {
8556 tree thunks;
8564 {
8574 else
8580 }
8584 }
8586 /* Dump the thunks for FN. */
8588 void
8590 {
8592 }
8594 /* Virtual function table initialization. */
8596 /* Create all the necessary vtables for T and its base classes. */
8598 static void
8600 {
8601 tree vbase;
8605 /* We lay out the primary and secondary vtables in one contiguous
8606 vtable. The primary vtable is first, followed by the non-virtual
8607 secondary vtables in inheritance graph order. */
8611 /* Then come the virtual bases, also in inheritance graph order. */
8613 {
8617 }
8621 }
8623 /* Initialize the vtable for BINFO with the INITS. */
8625 static void
8627 {
8628 tree decl;
8634 }
8636 /* Build the VTT (virtual table table) for T.
8637 A class requires a VTT if it has virtual bases.
8639 This holds
8640 1 - primary virtual pointer for complete object T
8641 2 - secondary VTTs for each direct non-virtual base of T which requires a
8642 VTT
8643 3 - secondary virtual pointers for each direct or indirect base of T which
8644 has virtual bases or is reachable via a virtual path from T.
8645 4 - secondary VTTs for each direct or indirect virtual base of T.
8647 Secondary VTTs look like complete object VTTs without part 4. */
8649 static void
8651 {
8652 tree type;
8653 tree vtt;
8654 tree index;
8657 /* Build up the initializers for the VTT. */
8662 /* If we didn't need a VTT, we're done. */
8666 /* Figure out the type of the VTT. */
8670 /* Now, build the VTT object itself. */
8673 /* Add the VTT to the vtables list. */
8678 }
8680 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8681 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8682 and CHAIN the vtable pointer for this binfo after construction is
8683 complete. VALUE can also be another BINFO, in which case we recurse. */
8685 static tree
8687 {
8688 tree vt;
8691 {
8697 else
8699 }
8702 }
8704 /* Data for secondary VTT initialization. */
8705 struct secondary_vptr_vtt_init_data
8706 {
8707 /* Is this the primary VTT? */
8710 /* Current index into the VTT. */
8711 tree index;
8713 /* Vector of initializers built up. */
8716 /* The type being constructed by this secondary VTT. */
8717 tree type_being_constructed;
8718 };
8720 /* Recursively build the VTT-initializer for BINFO (which is in the
8721 hierarchy dominated by T). INITS points to the end of the initializer
8722 list to date. INDEX is the VTT index where the next element will be
8723 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8724 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8725 for virtual bases of T. When it is not so, we build the constructor
8726 vtables for the BINFO-in-T variant. */
8728 static void
8731 {
8733 tree b;
8734 tree init;
8735 secondary_vptr_vtt_init_data data;
8738 /* We only need VTTs for subobjects with virtual bases. */
8742 /* We need to use a construction vtable if this is not the primary
8743 VTT. */
8745 {
8748 /* Record the offset in the VTT where this sub-VTT can be found. */
8750 }
8752 /* Add the address of the primary vtable for the complete object. */
8756 {
8759 }
8762 /* Recursively add the secondary VTTs for non-virtual bases. */
8767 /* Add secondary virtual pointers for all subobjects of BINFO with
8768 either virtual bases or reachable along a virtual path, except
8769 subobjects that are non-virtual primary bases. */
8779 /* data.inits might have grown as we added secondary virtual pointers.
8780 Make sure our caller knows about the new vector. */
8784 /* Add the secondary VTTs for virtual bases in inheritance graph
8785 order. */
8787 {
8792 }
8793 else
8794 /* Remove the ctor vtables we created. */
8796 }
8798 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8799 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8801 static tree
8803 {
8806 /* We don't care about bases that don't have vtables. */
8810 /* We're only interested in proper subobjects of the type being
8811 constructed. */
8815 /* We're only interested in bases with virtual bases or reachable
8816 via a virtual path from the type being constructed. */
8821 /* We're not interested in non-virtual primary bases. */
8825 /* Record the index where this secondary vptr can be found. */
8827 {
8832 {
8833 /* It's a primary virtual base, and this is not a
8834 construction vtable. Find the base this is primary of in
8835 the inheritance graph, and use that base's vtable
8836 now. */
8839 }
8840 }
8842 /* Add the initializer for the secondary vptr itself. */
8845 /* Advance the vtt index. */
8850 }
8852 /* Called from build_vtt_inits via dfs_walk. After building
8853 constructor vtables and generating the sub-vtt from them, we need
8854 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8855 binfo of the base whose sub vtt was generated. */
8857 static tree
8859 {
8863 /* If this class has no vtable, none of its bases do. */
8867 /* This might be a primary base, so have no vtable in this
8868 hierarchy. */
8871 /* If we scribbled the construction vtable vptr into BINFO, clear it
8872 out now. */
8878 }
8880 /* Build the construction vtable group for BINFO which is in the
8881 hierarchy dominated by T. */
8883 static void
8885 {
8886 tree type;
8887 tree vtbl;
8888 tree id;
8889 tree vbase;
8892 /* See if we've already created this construction vtable group. */
8898 /* Build a version of VTBL (with the wrong type) for use in
8899 constructing the addresses of secondary vtables in the
8900 construction vtable group. */
8903 /* Don't export construction vtables from shared libraries. Even on
8904 targets that don't support hidden visibility, this tells
8905 can_refer_decl_in_current_unit_p not to assume that it's safe to
8906 access from a different compilation unit (bz 54314). */
8914 /* Add the vtables for each of our virtual bases using the vbase in T
8915 binfo. */
8917 vbase;
8919 {
8920 tree b;
8927 }
8929 /* Figure out the type of the construction vtable. */
8936 /* Initialize the construction vtable. */
8940 }
8942 /* Add the vtbl initializers for BINFO (and its bases other than
8943 non-virtual primaries) to the list of INITS. BINFO is in the
8944 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
8945 the constructor the vtbl inits should be accumulated for. (If this
8946 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
8947 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
8948 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
8949 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
8950 but are not necessarily the same in terms of layout. */
8952 static void
8954 tree orig_binfo,
8955 tree rtti_binfo,
8956 tree vtbl,
8957 tree t,
8959 {
8961 tree base_binfo;
8966 /* If it doesn't have a vptr, we don't do anything. */
8970 /* If we're building a construction vtable, we're not interested in
8971 subobjects that don't require construction vtables. */
8977 /* Build the initializers for the BINFO-in-T vtable. */
8980 /* Walk the BINFO and its bases. We walk in preorder so that as we
8981 initialize each vtable we can figure out at what offset the
8982 secondary vtable lies from the primary vtable. We can't use
8983 dfs_walk here because we need to iterate through bases of BINFO
8984 and RTTI_BINFO simultaneously. */
8986 {
8987 /* Skip virtual bases. */
8993 inits);
8994 }
8995 }
8997 /* Called from accumulate_vtbl_inits. Adds the initializers for the
8998 BINFO vtable to L. */
9000 static void
9002 tree orig_binfo,
9003 tree rtti_binfo,
9004 tree orig_vtbl,
9005 tree t,
9007 {
9014 {
9015 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9016 primary virtual base. If it is not the same primary in
9017 the hierarchy of T, we'll need to generate a ctor vtable
9018 for it, to place at its location in T. If it is the same
9019 primary, we still need a VTT entry for the vtable, but it
9020 should point to the ctor vtable for the base it is a
9021 primary for within the sub-hierarchy of RTTI_BINFO.
9023 There are three possible cases:
9025 1) We are in the same place.
9026 2) We are a primary base within a lost primary virtual base of
9027 RTTI_BINFO.
9028 3) We are primary to something not a base of RTTI_BINFO. */
9030 tree b;
9033 /* First, look through the bases we are primary to for RTTI_BINFO
9034 or a virtual base. */
9037 {
9042 }
9043 /* If we run out of primary links, keep looking down our
9044 inheritance chain; we might be an indirect primary. */
9048 found:
9050 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9051 base B and it is a base of RTTI_BINFO, this is case 2. In
9052 either case, we share our vtable with LAST, i.e. the
9053 derived-most base within B of which we are a primary. */
9056 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9057 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9058 binfo_ctor_vtable after everything's been set up. */
9061 /* Otherwise, this is case 3 and we get our own. */
9062 }
9069 {
9070 tree index;
9073 /* Add the initializer for this vtable. */
9077 /* Figure out the position to which the VPTR should point. */
9083 }
9086 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9087 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9088 straighten this out. */
9091 /* Throw away any unneeded intializers. */
9093 else
9094 /* For an ordinary vtable, set BINFO_VTABLE. */
9096 }
9101 /* Construct the initializer for BINFO's virtual function table. BINFO
9102 is part of the hierarchy dominated by T. If we're building a
9103 construction vtable, the ORIG_BINFO is the binfo we should use to
9104 find the actual function pointers to put in the vtable - but they
9105 can be overridden on the path to most-derived in the graph that
9106 ORIG_BINFO belongs. Otherwise,
9107 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9108 BINFO that should be indicated by the RTTI information in the
9109 vtable; it will be a base class of T, rather than T itself, if we
9110 are building a construction vtable.
9112 The value returned is a TREE_LIST suitable for wrapping in a
9113 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9114 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9115 number of non-function entries in the vtable.
9117 It might seem that this function should never be called with a
9118 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9119 base is always subsumed by a derived class vtable. However, when
9120 we are building construction vtables, we do build vtables for
9121 primary bases; we need these while the primary base is being
9122 constructed. */
9124 static void
9126 tree orig_binfo,
9127 tree t,
9128 tree rtti_binfo,
9131 {
9132 tree v;
9133 vtbl_init_data vid;
9135 tree vbinfo;
9139 /* Initialize VID. */
9147 /* The first vbase or vcall offset is at index -3 in the vtable. */
9150 /* Add entries to the vtable for RTTI. */
9153 /* Create an array for keeping track of the functions we've
9154 processed. When we see multiple functions with the same
9155 signature, we share the vcall offsets. */
9157 /* Add the vcall and vbase offset entries. */
9160 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9161 build_vbase_offset_vtbl_entries. */
9166 /* If the target requires padding between data entries, add that now. */
9168 {
9173 /* Move data entries into their new positions and add padding
9174 after the new positions. Iterate backwards so we don't
9175 overwrite entries that we would need to process later. */
9178 ix--)
9179 {
9187 {
9191 null_pointer_node);
9192 }
9193 }
9194 }
9199 /* The initializers for virtual functions were built up in reverse
9200 order. Straighten them out and add them to the running list in one
9201 step. */
9210 /* Go through all the ordinary virtual functions, building up
9211 initializers. */
9213 {
9214 tree delta;
9215 tree vcall_index;
9222 {
9226 {
9229 }
9231 }
9233 /* If the only definition of this function signature along our
9234 primary base chain is from a lost primary, this vtable slot will
9235 never be used, so just zero it out. This is important to avoid
9236 requiring extra thunks which cannot be generated with the function.
9238 We first check this in update_vtable_entry_for_fn, so we handle
9239 restored primary bases properly; we also need to do it here so we
9240 zero out unused slots in ctor vtables, rather than filling them
9241 with erroneous values (though harmless, apart from relocation
9242 costs). */
9247 {
9248 /* Pull the offset for `this', and the function to call, out of
9249 the list. */
9256 /* You can't call an abstract virtual function; it's abstract.
9257 So, we replace these functions with __pure_virtual. */
9259 {
9262 {
9264 abort_fndecl_addr
9268 }
9269 }
9270 /* Likewise for deleted virtuals. */
9272 {
9274 {
9278 dvirt_fn = push_library_fn
9282 }
9287 }
9288 else
9289 {
9291 {
9296 }
9297 /* Take the address of the function, considering it to be of an
9298 appropriate generic type. */
9302 /* Don't refer to a virtual destructor from a constructor
9303 vtable or a vtable for an abstract class, since destroying
9304 an object under construction is undefined behavior and we
9305 don't want it to be considered a candidate for speculative
9306 devirtualization. But do create the thunk for ABI
9307 compliance. */
9312 }
9313 }
9315 /* And add it to the chain of initializers. */
9317 {
9322 else
9324 {
9330 }
9331 }
9332 else
9334 }
9335 }
9337 /* Adds to vid->inits the initializers for the vbase and vcall
9338 offsets in BINFO, which is in the hierarchy dominated by T. */
9340 static void
9342 {
9343 tree b;
9345 /* If this is a derived class, we must first create entries
9346 corresponding to the primary base class. */
9351 /* Add the vbase entries for this base. */
9353 /* Add the vcall entries for this base. */
9355 }
9357 /* Returns the initializers for the vbase offset entries in the vtable
9358 for BINFO (which is part of the class hierarchy dominated by T), in
9359 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9360 where the next vbase offset will go. */
9362 static void
9364 {
9365 tree vbase;
9366 tree t;
9367 tree non_primary_binfo;
9369 /* If there are no virtual baseclasses, then there is nothing to
9370 do. */
9376 /* We might be a primary base class. Go up the inheritance hierarchy
9377 until we find the most derived class of which we are a primary base:
9378 it is the offset of that which we need to use. */
9381 {
9382 tree b;
9384 /* If we have reached a virtual base, then it must be a primary
9385 base (possibly multi-level) of vid->binfo, or we wouldn't
9386 have called build_vcall_and_vbase_vtbl_entries for it. But it
9387 might be a lost primary, so just skip down to vid->binfo. */
9389 {
9392 }
9398 }
9400 /* Go through the virtual bases, adding the offsets. */
9402 vbase;
9404 {
9405 tree b;
9406 tree delta;
9411 /* Find the instance of this virtual base in the complete
9412 object. */
9415 /* If we've already got an offset for this virtual base, we
9416 don't need another one. */
9421 /* Figure out where we can find this vbase offset. */
9430 /* The vbase offset had better be the same. */
9433 /* The next vbase will come at a more negative offset. */
9437 /* The initializer is the delta from BINFO to this virtual base.
9438 The vbase offsets go in reverse inheritance-graph order, and
9439 we are walking in inheritance graph order so these end up in
9440 the right order. */
9447 }
9448 }
9450 /* Adds the initializers for the vcall offset entries in the vtable
9451 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9452 to VID->INITS. */
9454 static void
9456 {
9457 /* We only need these entries if this base is a virtual base. We
9458 compute the indices -- but do not add to the vtable -- when
9459 building the main vtable for a class. */
9462 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9463 correspond to VID->DERIVED), we are building a primary
9464 construction virtual table. Since this is a primary
9465 virtual table, we do not need the vcall offsets for
9466 BINFO. */
9468 {
9469 /* We need a vcall offset for each of the virtual functions in this
9470 vtable. For example:
9472 class A { virtual void f (); };
9473 class B1 : virtual public A { virtual void f (); };
9474 class B2 : virtual public A { virtual void f (); };
9475 class C: public B1, public B2 { virtual void f (); };
9477 A C object has a primary base of B1, which has a primary base of A. A
9478 C also has a secondary base of B2, which no longer has a primary base
9479 of A. So the B2-in-C construction vtable needs a secondary vtable for
9480 A, which will adjust the A* to a B2* to call f. We have no way of
9481 knowing what (or even whether) this offset will be when we define B2,
9482 so we store this "vcall offset" in the A sub-vtable and look it up in
9483 a "virtual thunk" for B2::f.
9485 We need entries for all the functions in our primary vtable and
9486 in our non-virtual bases' secondary vtables. */
9488 /* If we are just computing the vcall indices -- but do not need
9489 the actual entries -- not that. */
9492 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9494 }
9495 }
9497 /* Build vcall offsets, starting with those for BINFO. */
9499 static void
9501 {
9503 tree primary_binfo;
9504 tree base_binfo;
9506 /* Don't walk into virtual bases -- except, of course, for the
9507 virtual base for which we are building vcall offsets. Any
9508 primary virtual base will have already had its offsets generated
9509 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9513 /* If BINFO has a primary base, process it first. */
9518 /* Add BINFO itself to the list. */
9521 /* Scan the non-primary bases of BINFO. */
9525 }
9527 /* Called from build_vcall_offset_vtbl_entries_r. */
9529 static void
9531 {
9532 /* Make entries for the rest of the virtuals. */
9533 tree orig_fn;
9535 /* The ABI requires that the methods be processed in declaration
9536 order. */
9538 orig_fn;
9542 }
9544 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9546 static void
9548 {
9550 tree vcall_offset;
9551 tree derived_entry;
9553 /* If there is already an entry for a function with the same
9554 signature as FN, then we do not need a second vcall offset.
9555 Check the list of functions already present in the derived
9556 class vtable. */
9558 {
9560 /* We only use one vcall offset for virtual destructors,
9561 even though there are two virtual table entries. */
9565 }
9567 /* If we are building these vcall offsets as part of building
9568 the vtable for the most derived class, remember the vcall
9569 offset. */
9571 {
9574 }
9576 /* The next vcall offset will be found at a more negative
9577 offset. */
9581 /* Keep track of this function. */
9585 {
9586 tree base;
9587 tree fn;
9589 /* Find the overriding function. */
9593 else
9594 {
9597 /* The vbase we're working on is a primary base of
9598 vid->binfo. But it might be a lost primary, so its
9599 BINFO_OFFSET might be wrong, so we just use the
9600 BINFO_OFFSET from vid->binfo. */
9606 vcall_offset);
9607 }
9608 /* Add the initializer to the vtable. */
9610 }
9611 }
9613 /* Return vtbl initializers for the RTTI entries corresponding to the
9614 BINFO's vtable. The RTTI entries should indicate the object given
9615 by VID->rtti_binfo. */
9617 static void
9619 {
9620 tree b;
9621 tree t;
9622 tree offset;
9623 tree decl;
9624 tree init;
9628 /* To find the complete object, we will first convert to our most
9629 primary base, and then add the offset in the vtbl to that value. */
9634 /* The second entry is the address of the typeinfo object. */
9637 else
9640 /* Convert the declaration to a type that can be stored in the
9641 vtable. */
9645 /* Add the offset-to-top entry. It comes earlier in the vtable than
9646 the typeinfo entry. Convert the offset to look like a
9647 function pointer, so that we can put it in the vtable. */
9650 }
9652 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9653 accessibility. */
9655 bool
9657 {
9660 }
9662 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9664 bool
9666 {
9670 }
9672 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9673 class between them, if any. */
9675 tree
9677 {
9689 {
9692 }
9696 }