| blob | 7b10b20ede5eac19ed85b22ac27e874b4a871b55 |
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 }
287 {
288 /* This can happen when adjust_result_of_qualified_name_lookup can't
289 find a unique base binfo in a call to a member function. We
290 couldn't give the diagnostic then since we might have been calling
291 a static member function, so we do it now. In other cases, eg.
292 during error recovery (c++/71979), we may not have a base at all. */
294 {
298 }
300 }
307 /* Nothing to do. */
311 {
313 {
315 {
318 "pointer to derived class %qT because the base is "
320 else
324 }
325 else
326 {
332 else
336 }
337 }
339 }
342 {
344 /* This must happen before the call to save_expr. */
346 }
347 else
353 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
354 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
355 expression returned matches the input. */
356 target_type = cp_build_qualified_type
360 /* Do we need to look in the vtable for the real offset? */
363 /* Don't bother with the calculations inside sizeof; they'll ICE if the
364 source type is incomplete and the pointer value doesn't matter. In a
365 template (even in instantiate_non_dependent_expr), we don't have vtables
366 set up properly yet, and the value doesn't matter there either; we're
367 just interested in the result of overload resolution. */
369 || processing_template_decl
371 {
374 }
377 {
383 }
385 /* If we're in an NSDMI, we don't have the full constructor context yet
386 that we need for converting to a virtual base, so just build a stub
387 CONVERT_EXPR and expand it later in bot_replace. */
390 {
394 }
396 /* Do we need to check for a null pointer? */
398 {
399 /* If we know the conversion will not actually change the value
400 of EXPR, then we can avoid testing the expression for NULL.
401 We have to avoid generating a COMPONENT_REF for a base class
402 field, because other parts of the compiler know that such
403 expressions are always non-NULL. */
407 }
409 /* Protect against multiple evaluation if necessary. */
413 /* Now that we've saved expr, build the real null test. */
415 {
419 /* This is a compiler generated comparison, don't emit
420 e.g. -Wnonnull-compare warning for it. */
422 }
424 /* If this is a simple base reference, express it as a COMPONENT_REF. */
426 /* We don't build base fields for empty bases, and they aren't very
427 interesting to the optimizers anyway. */
429 {
438 }
441 {
442 /* Going via virtual base V_BINFO. We need the static offset
443 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
444 V_BINFO. That offset is an entry in D_BINFO's vtable. */
445 tree v_offset;
448 {
449 /* In a base member initializer, we cannot rely on the
450 vtable being set up. We have to indirect via the
451 vtt_parm. */
452 tree t;
458 }
459 else
460 {
464 {
469 }
472 }
480 v_offset);
492 /* Negative fixed_type_p means this is a constructor or destructor;
493 virtual base layout is fixed in in-charge [cd]tors, but not in
494 base [cd]tors. */
495 offset = build_if_in_charge
497 v_offset);
498 else
500 }
508 {
513 }
514 else
517 indout:
519 {
523 }
525 out:
531 }
533 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
534 Perform a derived-to-base conversion by recursively building up a
535 sequence of COMPONENT_REFs to the appropriate base fields. */
537 static tree
539 {
542 tree field;
545 {
546 tree temp;
550 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
551 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
552 an lvalue in the front end; only _DECLs and _REFs are lvalues
553 in the back end. */
559 }
561 /* Recurse. */
566 /* Is this the base field created by build_base_field? */
570 /* If we're looking for a field in the most-derived class,
571 also check the field offset; we can have two base fields
572 of the same type if one is an indirect virtual base and one
573 is a direct non-virtual base. */
577 {
578 /* We don't use build_class_member_access_expr here, as that
579 has unnecessary checks, and more importantly results in
580 recursive calls to dfs_walk_once. */
586 /* Mark the expression const or volatile, as appropriate.
587 Even though we've dealt with the type above, we still have
588 to mark the expression itself. */
595 }
597 /* Didn't find the base field?!? */
599 }
601 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
602 type is a class type or a pointer to a class type. In the former
603 case, TYPE is also a class type; in the latter it is another
604 pointer type. If CHECK_ACCESS is true, an error message is emitted
605 if TYPE is inaccessible. If OBJECT has pointer type, the value is
606 assumed to be non-NULL. */
608 tree
610 tsubst_flags_t complain)
611 {
612 tree binfo;
613 tree object_type;
616 {
619 }
620 else
629 }
631 /* EXPR is an expression with unqualified class type. BASE is a base
632 binfo of that class type. Returns EXPR, converted to the BASE
633 type. This function assumes that EXPR is the most derived class;
634 therefore virtual bases can be found at their static offsets. */
636 tree
638 {
639 tree expr_type;
643 {
644 /* If this is a non-empty base, use a COMPONENT_REF. */
648 /* We use fold_build2 and fold_convert below to simplify the trees
649 provided to the optimizers. It is not safe to call these functions
650 when processing a template because they do not handle C++-specific
651 trees. */
659 }
662 }
664 \f
665 tree
667 {
671 /* Can happen in case of duplicate base types (c++/59082). */
675 /* First, convert to the requested type. */
680 /* Second, the requested type may not be the owner of its own vptr.
681 If not, convert to the base class that owns it. We cannot use
682 convert_to_base here, because VCONTEXT may appear more than once
683 in the inheritance hierarchy of TYPE, and thus direct conversion
684 between the types may be ambiguous. Following the path back up
685 one step at a time via primary bases avoids the problem. */
689 {
692 }
695 }
697 /* Given an object INSTANCE, return an expression which yields the
698 vtable element corresponding to INDEX. There are many special
699 cases for INSTANCE which we take care of here, mainly to avoid
700 creating extra tree nodes when we don't have to. */
702 static tree
704 {
705 tree aref;
708 /* Try to figure out what a reference refers to, and
709 access its virtual function table directly. */
717 {
722 }
731 }
733 tree
735 {
739 }
741 /* Given a stable object pointer INSTANCE_PTR, return an expression which
742 yields a function pointer corresponding to vtable element INDEX. */
744 tree
746 {
747 tree aref;
750 idx);
752 /* When using function descriptors, the address of the
753 vtable entry is treated as a function pointer. */
758 /* Remember this as a method reference, for later devirtualization. */
762 }
764 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
765 for the given TYPE. */
767 static tree
769 {
771 }
773 /* DECL is an entity associated with TYPE, like a virtual table or an
774 implicitly generated constructor. Determine whether or not DECL
775 should have external or internal linkage at the object file
776 level. This routine does not deal with COMDAT linkage and other
777 similar complexities; it simply sets TREE_PUBLIC if it possible for
778 entities in other translation units to contain copies of DECL, in
779 the abstract. */
781 void
783 {
786 }
788 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
789 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
790 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
792 static tree
794 {
795 tree decl;
798 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
799 now to avoid confusion in mangle_decl. */
810 /* The vtable has not been defined -- yet. */
814 /* Mark the VAR_DECL node representing the vtable itself as a
815 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
816 is rather important that such things be ignored because any
817 effort to actually generate DWARF for them will run into
818 trouble when/if we encounter code like:
820 #pragma interface
821 struct S { virtual void member (); };
823 because the artificial declaration of the vtable itself (as
824 manufactured by the g++ front end) will say that the vtable is
825 a static member of `S' but only *after* the debug output for
826 the definition of `S' has already been output. This causes
827 grief because the DWARF entry for the definition of the vtable
828 will try to refer back to an earlier *declaration* of the
829 vtable as a static member of `S' and there won't be one. We
830 might be able to arrange to have the "vtable static member"
831 attached to the member list for `S' before the debug info for
832 `S' get written (which would solve the problem) but that would
833 require more intrusive changes to the g++ front end. */
837 }
839 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
840 or even complete. If this does not exist, create it. If COMPLETE is
841 nonzero, then complete the definition of it -- that will render it
842 impossible to actually build the vtable, but is useful to get at those
843 which are known to exist in the runtime. */
845 tree
847 {
848 tree decl;
857 {
860 }
863 }
865 /* Build the primary virtual function table for TYPE. If BINFO is
866 non-NULL, build the vtable starting with the initial approximation
867 that it is the same as the one which is the head of the association
868 list. Returns a nonzero value if a new vtable is actually
869 created. */
871 static int
873 {
874 tree decl;
875 tree virtuals;
880 {
882 /* We have already created a vtable for this base, so there's
883 no need to do it again. */
890 }
891 else
892 {
895 }
897 /* Initialize the association list for this type, based
898 on our first approximation. */
903 }
905 /* Give BINFO a new virtual function table which is initialized
906 with a skeleton-copy of its original initialization. The only
907 entry that changes is the `delta' entry, so we can really
908 share a lot of structure.
910 FOR_TYPE is the most derived type which caused this table to
911 be needed.
913 Returns nonzero if we haven't met BINFO before.
915 The order in which vtables are built (by calling this function) for
916 an object must remain the same, otherwise a binary incompatibility
917 can result. */
919 static int
921 {
923 /* We already created a vtable for this base. There's no need to
924 do it again. */
927 /* Remember that we've created a vtable for this BINFO, so that we
928 don't try to do so again. */
931 /* Make fresh virtual list, so we can smash it later. */
934 /* Secondary vtables are laid out as part of the same structure as
935 the primary vtable. */
938 }
940 /* Create a new vtable for BINFO which is the hierarchy dominated by
941 T. Return nonzero if we actually created a new vtable. */
943 static int
945 {
947 /* In this case, it is *type*'s vtable we are modifying. We start
948 with the approximation that its vtable is that of the
949 immediate base class. */
951 else
952 /* This is our very own copy of `basetype' to play with. Later,
953 we will fill in all the virtual functions that override the
954 virtual functions in these base classes which are not defined
955 by the current type. */
957 }
959 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
960 (which is in the hierarchy dominated by T) list FNDECL as its
961 BV_FN. DELTA is the required constant adjustment from the `this'
962 pointer where the vtable entry appears to the `this' required when
963 the function is actually called. */
965 static void
967 tree binfo,
968 tree fndecl,
969 tree delta,
971 {
972 tree v;
978 {
979 /* We need a new vtable for BINFO. */
981 {
982 /* If we really did make a new vtable, we also made a copy
983 of the BINFO_VIRTUALS list. Now, we have to find the
984 corresponding entry in that list. */
989 }
994 }
995 }
997 \f
998 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
999 METHOD is being injected via a using_decl. Returns true if the
1000 method could be added to the method vec. */
1002 bool
1004 {
1013 /* Check to see if we've already got this method. */
1015 {
1017 tree fn_type;
1018 tree method_type;
1019 tree parms1;
1020 tree parms2;
1025 /* Two using-declarations can coexist, we'll complain about ambiguity in
1026 overload resolution. */
1028 /* Except handle inherited constructors specially. */
1032 /* [over.load] Member function declarations with the
1033 same name and the same parameter types cannot be
1034 overloaded if any of them is a static member
1035 function declaration.
1037 [over.load] Member function declarations with the same name and
1038 the same parameter-type-list as well as member function template
1039 declarations with the same name, the same parameter-type-list, and
1040 the same template parameter lists cannot be overloaded if any of
1041 them, but not all, have a ref-qualifier.
1043 [namespace.udecl] When a using-declaration brings names
1044 from a base class into a derived class scope, member
1045 functions in the derived class override and/or hide member
1046 functions with the same name and parameter types in a base
1047 class (rather than conflicting). */
1053 /* Compare the quals on the 'this' parm. Don't compare
1054 the whole types, as used functions are treated as
1055 coming from the using class in overload resolution. */
1058 /* Either both or neither need to be ref-qualified for
1059 differing quals to allow overloading. */
1066 /* For templates, the return type and template parameters
1067 must be identical. */
1080 /* Bring back parameters omitted from an inherited ctor. */
1091 {
1092 /* If these are versions of the same function, process and
1093 move on. */
1099 {
1101 {
1105 {
1107 {
1108 /* Inheriting the same constructor along different
1109 paths, combine them. */
1110 SET_DECL_INHERITED_CTOR
1113 /* And discard the new one. */
1115 }
1116 else
1117 /* Inherited ctors can coexist until overload
1118 resolution. */
1120 }
1126 basef);
1127 }
1128 /* Otherwise defer to the other function. */
1130 }
1133 /* Defer to the local function. */
1137 {
1138 /* Remove the inherited constructor. */
1141 }
1142 else
1143 {
1149 }
1150 }
1151 }
1153 /* A class should never have more than one destructor. */
1165 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1171 }
1173 /* Subroutines of finish_struct. */
1175 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1176 legit, otherwise return 0. */
1178 static int
1180 {
1181 tree elem;
1189 {
1191 {
1195 else
1198 }
1199 else
1200 {
1201 /* They're changing the access to the same thing they changed
1202 it to before. That's OK. */
1203 ;
1204 }
1205 }
1206 else
1207 {
1209 tf_warning_or_error);
1212 }
1214 }
1216 /* Return the access node for DECL's access in its enclosing class. */
1218 tree
1220 {
1224 }
1226 /* Process the USING_DECL, which is a member of T. */
1228 static void
1230 {
1235 tree old_value;
1240 tf_warning_or_error);
1242 {
1247 else
1249 }
1257 ;
1259 {
1261 /* It's OK to use functions from a base when there are functions with
1263 else
1264 {
1271 }
1272 }
1274 {
1281 }
1283 /* Make type T see field decl FDECL with access ACCESS. */
1286 {
1289 }
1290 else
1292 }
1293 \f
1294 /* Data structure for find_abi_tags_r, below. */
1296 struct abi_tag_data
1297 {
1301 };
1303 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1304 in the context of P. TAG can be either an identifier (the DECL_NAME of
1305 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1307 static void
1309 {
1311 {
1313 {
1314 /* We're collecting tags from template arguments or from
1315 the type of a variable or function return type. */
1318 /* Don't inherit this tag multiple times. */
1322 {
1323 /* Tags inherited from type template arguments are only used
1324 to avoid warnings. */
1327 }
1328 /* For functions and variables we want to warn, too. */
1329 }
1331 /* Otherwise we're diagnosing missing tags. */
1333 {
1338 }
1340 {
1344 }
1346 {
1351 }
1352 else
1353 {
1357 {
1361 }
1362 }
1363 }
1364 }
1366 /* Find all the ABI tags in the attribute list ATTR and either call
1367 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1369 static void
1371 {
1378 {
1383 else
1385 }
1386 }
1388 /* Find all the ABI tags on T and its enclosing scopes and either call
1389 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1391 static void
1393 {
1395 {
1396 tree attr;
1398 {
1401 }
1402 else
1403 {
1406 }
1408 }
1409 }
1411 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1412 types with ABI tags, add the corresponding identifiers to the VEC in
1413 *DATA and set IDENTIFIER_MARKED. */
1415 static tree
1417 {
1421 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1422 anyway, but let's make sure of it. */
1430 }
1432 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1433 IDENTIFIER_MARKED on its ABI tags. */
1435 static tree
1437 {
1441 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1442 anyway, but let's make sure of it. */
1450 }
1452 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1453 scopes. */
1455 static void
1457 {
1460 {
1463 {
1464 /* Template arguments are part of the signature. */
1467 {
1470 }
1471 }
1473 /* A function's parameter types are part of the signature, so
1474 we don't need to inherit any tags that are also in them. */
1479 }
1480 }
1482 /* Check that T has all the ABI tags that subobject SUBOB has, or
1483 warn if not. If T is a (variable or function) declaration, also
1484 return any missing tags, and add them to T if JUST_CHECKING is false. */
1486 static tree
1488 {
1496 /* No need to worry about things local to this TU. */
1512 {
1515 }
1516 else
1517 {
1521 else
1524 }
1529 }
1531 /* Check that DECL has all the ABI tags that are used in parts of its type
1532 that are not reflected in its mangled name. */
1534 void
1536 {
1543 }
1545 /* Return any ABI tags that are used in parts of the type of DECL
1546 that are not reflected in its mangled name. This function is only
1547 used in backward-compatible mangling for ABI <11. */
1549 tree
1551 {
1555 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1556 that we can use this function for setting need_abi_warning
1557 regardless of the current flag_abi_version. */
1560 else
1562 }
1564 void
1566 {
1576 {
1579 {
1583 }
1584 }
1586 // If we found some tags on our template arguments, add them to our
1587 // abi_tag attribute.
1589 {
1593 else
1596 }
1599 }
1601 /* Return true, iff class T has a non-virtual destructor that is
1602 accessible from outside the class heirarchy (i.e. is public, or
1603 there's a suitable friend. */
1605 static bool
1607 {
1610 /* An implicitly declared destructor is always public. And,
1611 if it were virtual, we would have created it by now. */
1626 }
1628 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1629 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1630 properties of the bases. */
1632 static void
1636 {
1640 tree base_binfo;
1641 tree binfo;
1651 {
1660 /* If any base class is non-literal, so is the derived class. */
1664 /* If the base class doesn't have copy constructors or
1665 assignment operators that take const references, then the
1666 derived class cannot have such a member automatically
1667 generated. */
1676 /* A virtual base does not effect nearly emptiness. */
1677 ;
1679 {
1681 /* And if there is more than one nearly empty base, then the
1682 derived class is not nearly empty either. */
1684 else
1685 /* Remember we've seen one. */
1687 }
1689 /* If the base class is not empty or nearly empty, then this
1690 class cannot be nearly empty. */
1693 /* A lot of properties from the bases also apply to the derived
1694 class. */
1711 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1714 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1720 /* A standard-layout class is a class that:
1721 ...
1722 * has no non-standard-layout base classes, */
1725 {
1726 tree basefield;
1727 /* ...has no base classes of the same type as the first non-static
1728 data member... */
1730 && (same_type_ignoring_top_level_qualifiers_p
1733 else
1734 /* ...either has no non-static data members in the most-derived
1735 class and at most one base class with non-static data
1736 members, or has no base classes with non-static data
1737 members */
1743 {
1746 else
1749 }
1750 }
1752 /* Don't bother collecting tm attributes if transactional memory
1753 support is not enabled. */
1755 {
1759 }
1762 }
1764 /* If one of the base classes had TM attributes, and the current class
1765 doesn't define its own, then the current class inherits one. */
1767 {
1770 }
1771 }
1773 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1774 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1775 that have had a nearly-empty virtual primary base stolen by some
1776 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1777 T. */
1779 static void
1781 {
1785 tree base_binfo;
1787 /* Determine the primary bases of our bases. */
1790 {
1793 /* See if we're the non-virtual primary of our inheritance
1794 chain. */
1796 {
1803 /* We are the primary binfo. */
1805 }
1806 /* Determine if we have a virtual primary base, and mark it so.
1807 */
1809 {
1813 /* Someone already claimed this base. */
1815 else
1816 {
1817 tree delta;
1822 /* A virtual binfo might have been copied from within
1823 another hierarchy. As we're about to use it as a
1824 primary base, make sure the offsets match. */
1832 }
1833 }
1834 }
1836 /* First look for a dynamic direct non-virtual base. */
1838 {
1842 {
1845 }
1846 }
1848 /* A "nearly-empty" virtual base class can be the primary base
1849 class, if no non-virtual polymorphic base can be found. Look for
1850 a nearly-empty virtual dynamic base that is not already a primary
1851 base of something in the hierarchy. If there is no such base,
1852 just pick the first nearly-empty virtual base. */
1858 {
1860 {
1861 /* Found one that is not primary. */
1864 }
1866 /* Remember the first candidate. */
1868 }
1870 found:
1871 /* If we've got a primary base, use it. */
1873 {
1878 /* We are stealing a primary base. */
1882 {
1883 tree delta;
1886 /* A virtual binfo might have been copied from within
1887 another hierarchy. As we're about to use it as a primary
1888 base, make sure the offsets match. */
1893 }
1900 }
1901 }
1903 /* Update the variant types of T. */
1905 void
1907 {
1908 tree variants;
1914 variants;
1916 {
1917 /* These fields are in the _TYPE part of the node, not in
1918 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1928 /* Copy whatever these are holding today. */
1931 }
1932 }
1934 /* KLASS is a class that we're applying may_alias to after the body is
1935 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
1936 canonical type(s) will be implicitly updated. */
1938 static void
1940 {
1949 }
1951 /* Early variant fixups: we apply attributes at the beginning of the class
1952 definition, and we need to fix up any variants that have already been
1953 made via elaborated-type-specifier so that check_qualified_type works. */
1955 void
1957 {
1958 tree variants;
1972 variants;
1974 {
1975 /* These are the two fields that check_qualified_type looks at and
1976 are affected by attributes. */
1981 else
1986 }
1987 }
1988 \f
1989 /* Set memoizing fields and bits of T (and its variants) for later
1990 use. */
1992 static void
1994 {
1995 /* Fix up variants (if any). */
1999 /* For a class w/o baseclasses, 'finish_struct' has set
2000 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2001 Similarly for a class whose base classes do not have vtables.
2002 When neither of these is true, we might have removed abstract
2003 virtuals (by providing a definition), added some (by declaring
2004 new ones), or redeclared ones from a base class. We need to
2005 recalculate what's really an abstract virtual at this point (by
2006 looking in the vtables). */
2009 /* If this type has a copy constructor or a destructor, force its
2010 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2011 nonzero. This will cause it to be passed by invisible reference
2012 and prevent it from being returned in a register. */
2015 {
2016 tree variants;
2019 {
2022 }
2023 }
2024 }
2026 /* Issue warnings about T having private constructors, but no friends,
2027 and so forth.
2029 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2030 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2031 non-private static member functions. */
2033 static void
2035 {
2041 /* If the class has friends, those entities might create and
2042 access instances, so we should not warn. */
2045 /* We will have warned when the template was declared; there's
2046 no need to warn on every instantiation. */
2048 /* There's no reason to even consider warning about this
2049 class. */
2052 /* We only issue one warning, if more than one applies, because
2053 otherwise, on code like:
2055 class A {
2056 // Oops - forgot `public:'
2057 A();
2058 A(const A&);
2059 ~A();
2060 };
2062 we warn several times about essentially the same problem. */
2064 /* Check to see if all (non-constructor, non-destructor) member
2065 functions are private. (Since there are no friends or
2066 non-private statics, we can't ever call any of the private member
2067 functions.) */
2076 /* We're not interested in compiler-generated methods; they don't
2079 {
2081 /* A non-private static member function is just like a
2082 friend; it can create and invoke private member
2083 functions, and be accessed without a class
2084 instance. */
2088 /* Keep searching for a static member function. */
2089 }
2094 {
2095 /* There are no non-private methods, and there's at least one
2096 private member function that isn't a constructor or
2097 destructor. (If all the private members are
2098 constructors/destructors we want to use the code below that
2099 issues error messages specifically referring to
2100 constructors/destructors.) */
2106 {
2109 }
2111 {
2115 }
2116 }
2118 /* Even if some of the member functions are non-private, the class
2119 won't be useful for much if all the constructors or destructors
2120 are private: such an object can never be created or destroyed. */
2123 {
2126 t);
2128 }
2130 /* Warn about classes that have private constructors and no friends. */
2132 /* Implicitly generated constructors are always public. */
2134 {
2137 /* If a non-template class does not define a copy
2138 constructor, one is defined for it, enabling it to avoid
2139 this warning. For a template class, this does not
2140 happen, and so we would normally get a warning on:
2142 template <class T> class C { private: C(); };
2144 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2145 complete non-template or fully instantiated classes have this
2146 flag set. */
2149 else
2155 /* Ideally, we wouldn't count any constructor that takes
2156 an argument of the class type as a parameter, because
2157 such things cannot be used to construct an instance of
2158 the class unless you already have one. */
2160 else
2164 {
2167 t);
2173 }
2174 }
2175 }
2177 /* Make BINFO's vtable have N entries, including RTTI entries,
2178 vbase and vcall offsets, etc. Set its type and call the back end
2179 to lay it out. */
2181 static void
2183 {
2184 tree atype;
2185 tree vtable;
2190 /* We may have to grow the vtable. */
2193 {
2197 }
2198 }
2200 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2201 have the same signature. */
2203 int
2205 {
2206 /* One destructor overrides another if they are the same kind of
2207 destructor. */
2211 /* But a non-destructor never overrides a destructor, nor vice
2212 versa, nor do different kinds of destructors override
2213 one-another. For example, a complete object destructor does not
2214 override a deleting destructor. */
2223 {
2231 }
2233 }
2235 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2236 subobject. */
2238 static bool
2240 {
2241 tree probe;
2244 {
2248 /* If we meet a virtual base, we can't follow the inheritance
2249 any more. See if the complete type of DERIVED contains
2250 such a virtual base. */
2253 }
2255 }
2258 /* The function for which we are trying to find a final overrider. */
2259 tree fn;
2260 /* The base class in which the function was declared. */
2261 tree declaring_base;
2262 /* The candidate overriders. */
2263 tree candidates;
2264 /* Path to most derived. */
2266 };
2268 /* Add the overrider along the current path to FFOD->CANDIDATES.
2269 Returns true if an overrider was found; false otherwise. */
2271 static bool
2275 {
2276 tree method;
2278 /* If BINFO is not the most derived type, try a more derived class.
2279 A definition there will overrider a definition here. */
2281 {
2282 depth--;
2286 }
2290 {
2293 /* Remove any candidates overridden by this new function. */
2295 {
2296 /* If *CANDIDATE overrides METHOD, then METHOD
2297 cannot override anything else on the list. */
2300 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2303 else
2305 }
2307 /* Add the new function. */
2310 }
2313 }
2315 /* Called from find_final_overrider via dfs_walk. */
2317 static tree
2319 {
2327 }
2329 static tree
2331 {
2336 }
2338 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2339 FN and whose TREE_VALUE is the binfo for the base where the
2340 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2341 DERIVED) is the base object in which FN is declared. */
2343 static tree
2345 {
2346 find_final_overrider_data ffod;
2348 /* Getting this right is a little tricky. This is valid:
2350 struct S { virtual void f (); };
2351 struct T { virtual void f (); };
2352 struct U : public S, public T { };
2354 even though calling `f' in `U' is ambiguous. But,
2356 struct R { virtual void f(); };
2357 struct S : virtual public R { virtual void f (); };
2358 struct T : virtual public R { virtual void f (); };
2359 struct U : public S, public T { };
2361 is not -- there's no way to decide whether to put `S::f' or
2362 `T::f' in the vtable for `R'.
2364 The solution is to look at all paths to BINFO. If we find
2365 different overriders along any two, then there is a problem. */
2369 /* Determine the depth of the hierarchy. */
2380 /* If there was no winner, issue an error message. */
2385 }
2387 /* Return the index of the vcall offset for FN when TYPE is used as a
2388 virtual base. */
2390 static tree
2392 {
2394 tree_pair_p p;
2402 /* There should always be an appropriate index. */
2404 }
2406 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2407 dominated by T. FN is the old function; VIRTUALS points to the
2408 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2409 of that entry in the list. */
2411 static void
2414 {
2415 tree b;
2416 tree overrider;
2417 tree delta;
2418 tree virtual_base;
2419 tree first_defn;
2425 /* Find the nearest primary base (possibly binfo itself) which defines
2426 this function; this is the class the caller will convert to when
2427 calling FN through BINFO. */
2429 {
2434 /* The nearest definition is from a lost primary. */
2437 }
2440 /* Find the final overrider. */
2443 {
2446 }
2449 /* Check for adjusting covariant return types. */
2457 /* If the overrider is invalid, don't even try. */
2459 {
2460 /* If FN is a covariant thunk, we must figure out the adjustment
2461 to the final base FN was converting to. As OVERRIDER_TARGET might
2462 also be converting to the return type of FN, we have to
2463 combine the two conversions here. */
2470 {
2474 }
2475 else
2479 /* Find the equivalent binfo within the return type of the
2480 overriding function. We will want the vbase offset from
2481 there. */
2483 over_return);
2486 {
2487 /* There was no existing virtual thunk (which takes
2488 precedence). So find the binfo of the base function's
2489 return type within the overriding function's return type.
2490 Fortunately we know the covariancy is valid (it
2491 has already been checked), so we can just iterate along
2492 the binfos, which have been chained in inheritance graph
2493 order. Of course it is lame that we have to repeat the
2494 search here anyway -- we should really be caching pieces
2495 of the vtable and avoiding this repeated work. */
2499 /* Find the base binfo within the overriding function's
2500 return type. We will always find a thunk_binfo, except
2501 when the covariancy is invalid (which we will have
2502 already diagnosed). */
2511 /* See if virtual inheritance is involved. */
2513 virtual_offset;
2520 {
2524 {
2525 /* We convert via virtual base. Adjust the fixed
2526 offset to be from there. */
2527 offset =
2531 }
2533 /* There was an existing fixed offset, this must be
2534 from the base just converted to, and the base the
2535 FN was thunking to. */
2537 else
2539 }
2540 }
2543 /* Replace the overriding function with a covariant thunk. We
2544 will emit the overriding function in its own slot as
2545 well. */
2548 }
2549 else
2553 /* If we need a covariant thunk, then we may need to adjust first_defn.
2554 The ABI specifies that the thunks emitted with a function are
2555 determined by which bases the function overrides, so we need to be
2556 sure that we're using a thunk for some overridden base; even if we
2557 know that the necessary this adjustment is zero, there may not be an
2558 appropriate zero-this-adjustment thunk for us to use since thunks for
2559 overriding virtual bases always use the vcall offset.
2561 Furthermore, just choosing any base that overrides this function isn't
2562 quite right, as this slot won't be used for calls through a type that
2563 puts a covariant thunk here. Calling the function through such a type
2564 will use a different slot, and that slot is the one that determines
2565 the thunk emitted for that base.
2567 So, keep looking until we find the base that we're really overriding
2568 in this slot: the nearest primary base that doesn't use a covariant
2569 thunk in this slot. */
2571 {
2573 /* We already know that the overrider needs a covariant thunk. */
2576 {
2583 }
2585 }
2587 /* Assume that we will produce a thunk that convert all the way to
2588 the final overrider, and not to an intermediate virtual base. */
2591 /* See if we can convert to an intermediate virtual base first, and then
2592 use the vcall offset located there to finish the conversion. */
2594 {
2595 /* If we find the final overrider, then we can stop
2596 walking. */
2601 /* If we find a virtual base, and we haven't yet found the
2602 overrider, then there is a virtual base between the
2603 declaring base (first_defn) and the final overrider. */
2605 {
2608 }
2609 }
2611 /* Compute the constant adjustment to the `this' pointer. The
2612 `this' pointer, when this function is called, will point at BINFO
2613 (or one of its primary bases, which are at the same offset). */
2615 /* The `this' pointer needs to be adjusted from the declaration to
2616 the nearest virtual base. */
2621 /* If the nearest definition is in a lost primary, we don't need an
2622 entry in our vtable. Except possibly in a constructor vtable,
2623 if we happen to get our primary back. In that case, the offset
2624 will be zero, as it will be a primary base. */
2626 else
2627 /* The `this' pointer needs to be adjusted from pointing to
2628 BINFO to pointing at the base where the final overrider
2629 appears. */
2640 else
2644 }
2646 /* Called from modify_all_vtables via dfs_walk. */
2648 static tree
2650 {
2652 tree virtuals;
2653 tree old_virtuals;
2657 /* A base without a vtable needs no modification, and its bases
2658 are uninteresting. */
2663 /* Don't do the primary vtable, if it's new. */
2667 /* There's no need to modify the vtable for a non-virtual primary
2668 base; we're not going to use that vtable anyhow. We do still
2669 need to do this for virtual primary bases, as they could become
2670 non-primary in a construction vtable. */
2675 /* Now, go through each of the virtual functions in the virtual
2676 function table for BINFO. Find the final overrider, and update
2677 the BINFO_VIRTUALS list appropriately. */
2680 virtuals;
2684 binfo,
2689 }
2691 /* Update all of the primary and secondary vtables for T. Create new
2692 vtables as required, and initialize their RTTI information. Each
2693 of the functions in VIRTUALS is declared in T and may override a
2694 virtual function from a base class; find and modify the appropriate
2695 entries to point to the overriding functions. Returns a list, in
2696 declaration order, of the virtual functions that are declared in T,
2697 but do not appear in the primary base class vtable, and which
2698 should therefore be appended to the end of the vtable for T. */
2700 static tree
2702 {
2706 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2710 /* Update all of the vtables. */
2713 /* Add virtual functions not already in our primary vtable. These
2714 will be both those introduced by this class, and those overridden
2715 from secondary bases. It does not include virtuals merely
2716 inherited from secondary bases. */
2718 {
2723 {
2724 /* We don't need to adjust the `this' pointer when
2725 calling this function. */
2729 /* This is a function not already in our vtable. Keep it. */
2731 }
2732 else
2733 /* We've already got an entry for this function. Skip it. */
2735 }
2738 }
2740 /* Get the base virtual function declarations in T that have the
2741 indicated NAME. */
2743 static void
2745 {
2748 /* Find virtual functions in T with the indicated NAME. */
2750 {
2754 {
2757 }
2758 }
2765 {
2768 }
2769 }
2771 /* If this declaration supersedes the declaration of
2772 a method declared virtual in the base class, then
2773 mark this field as being virtual as well. */
2775 void
2777 {
2780 /* In [temp.mem] we have:
2782 A specialization of a member function template does not
2783 override a virtual function from a base class. */
2790 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2791 the error_mark_node so that we know it is an overriding
2792 function. */
2793 {
2800 }
2803 {
2809 }
2814 }
2816 /* Warn about hidden virtual functions that are not overridden in t.
2817 We know that constructors and destructors don't apply. */
2819 static void
2821 {
2824 {
2832 tree base_binfo;
2833 tree binfo;
2836 /* Iterate through all of the base classes looking for possibly
2837 hidden functions. */
2840 {
2843 }
2845 /* If there are no functions to hide, continue. */
2849 /* Remove any overridden functions. */
2851 {
2855 {
2856 /* If the method from the base class has the same
2857 signature as the method from the derived class, it
2858 has been overridden. */
2863 }
2864 }
2866 /* Now give a warning for all base functions without overriders,
2867 as they are hidden. */
2868 tree base_fndecl;
2871 {
2872 /* Here we know it is a hider, and no overrider exists. */
2874 OPT_Woverloaded_virtual,
2878 }
2879 }
2880 }
2882 /* Recursive helper for finish_struct_anon. */
2884 static void
2886 {
2888 {
2889 /* We're generally only interested in entities the user
2890 declared, but we also find nested classes by noticing
2891 the TYPE_DECL that we create implicitly. You're
2892 allowed to put one anonymous union inside another,
2893 though, so we explicitly tolerate that. We use
2894 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2895 we also allow unnamed types used for defining fields. */
2904 {
2905 /* We already complained about static data members in
2906 finish_static_data_member_decl. */
2911 "only have public non-static data members"
2914 {
2917 {
2921 }
2922 }
2923 }
2928 /* Recurse into the anonymous aggregates to correctly handle
2929 access control (c++/24926):
2931 class A {
2932 union {
2933 union {
2934 int i;
2935 };
2936 };
2937 };
2939 int j=A().i; */
2943 }
2944 }
2946 /* Check for things that are invalid. There are probably plenty of other
2947 things we should check for also. */
2949 static void
2951 {
2953 {
2962 }
2963 }
2965 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2966 will be used later during class template instantiation.
2967 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2968 a non-static member data (FIELD_DECL), a member function
2969 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2970 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2971 When FRIEND_P is nonzero, T is either a friend class
2972 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2973 (FUNCTION_DECL, TEMPLATE_DECL). */
2975 void
2977 {
2978 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2983 }
2985 /* This function is called from declare_virt_assop_and_dtor via
2986 dfs_walk_all.
2988 DATA is a type that direcly or indirectly inherits the base
2989 represented by BINFO. If BINFO contains a virtual assignment [copy
2990 assignment or move assigment] operator or a virtual constructor,
2991 declare that function in DATA if it hasn't been already declared. */
2993 static tree
2995 {
3003 /* A base without a vtable needs no modification, and its bases
3004 are uninteresting. */
3008 /* If this is a primary base, then we have already looked at the
3009 virtual functions of its vtable. */
3013 {
3017 {
3022 }
3026 }
3029 }
3031 /* If the class type T has a direct or indirect base that contains a
3032 virtual assignment operator or a virtual destructor, declare that
3033 function in T if it hasn't been already declared. */
3035 static void
3037 {
3045 dfs_declare_virt_assop_and_dtor,
3047 }
3049 /* Declare the inheriting constructor for class T inherited from base
3050 constructor CTOR with the parameter array PARMS of size NPARMS. */
3052 static void
3054 {
3057 /* We don't declare an inheriting ctor that would be a default,
3058 copy or move ctor for derived or base. */
3063 {
3067 }
3076 {
3079 }
3080 }
3082 /* Declare all the inheriting constructors for class T inherited from base
3083 constructor CTOR. */
3085 static void
3087 {
3091 {
3097 }
3102 {
3106 }
3109 {
3113 }
3114 }
3116 /* Create default constructors, assignment operators, and so forth for
3117 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3118 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3119 the class cannot have a default constructor, copy constructor
3120 taking a const reference argument, or an assignment operator taking
3121 a const reference, respectively. */
3123 static void
3127 {
3128 /* Destructor. */
3130 /* In general, we create destructors lazily. */
3139 /* [class.ctor]
3141 If there is no user-declared constructor for a class, a default
3142 constructor is implicitly declared. */
3144 {
3149 /* Don't force the declaration to get a hard answer; if the
3150 definition would have made the class non-literal, it will still be
3151 non-literal because of the base or member in question, and that
3152 gives a better diagnostic. */
3154 }
3156 /* [class.ctor]
3158 If a class definition does not explicitly declare a copy
3159 constructor, one is declared implicitly. */
3161 {
3167 }
3169 /* If there is no assignment operator, one will be created if and
3170 when it is needed. For now, just record whether or not the type
3171 of the parameter to the assignment operator will be a const or
3172 non-const reference. */
3174 {
3180 }
3182 /* We can't be lazy about declaring functions that might override
3183 a virtual function from a base class. */
3187 {
3191 {
3192 /* declare, then remove the decl */
3200 }
3201 else
3203 }
3204 }
3206 /* FIELD is a bit-field. We are finishing the processing for its
3207 enclosing type. Issue any appropriate messages and set appropriate
3208 flags. Returns false if an error has been diagnosed. */
3210 static bool
3212 {
3214 tree w;
3216 /* Extract the declared width of the bitfield, which has been
3217 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3220 /* Remove the bit-field width indicator so that the rest of the
3221 compiler does not treat that value as a qualifier. */
3224 /* Detect invalid bit-field type. */
3226 {
3229 }
3230 else
3231 {
3233 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3236 /* detect invalid field size. */
3242 {
3245 }
3247 {
3250 }
3252 {
3255 }
3265 {
3271 }
3272 }
3275 {
3279 }
3280 else
3281 {
3282 /* Non-bit-fields are aligned for their type. */
3286 }
3287 }
3289 /* FIELD is a non bit-field. We are finishing the processing for its
3290 enclosing type T. Issue any appropriate messages and set appropriate
3291 flags. */
3293 static bool
3295 tree t,
3298 {
3302 /* In C++98 an anonymous union cannot contain any fields which would change
3303 the settings of CANT_HAVE_CONST_CTOR and friends. */
3305 ;
3306 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3307 structs. So, we recurse through their fields here. */
3309 {
3314 cant_have_const_ctor,
3315 no_const_asn_ref);
3316 }
3317 /* Check members with class type for constructors, destructors,
3318 etc. */
3320 {
3321 /* Never let anything with uninheritable virtuals
3322 make it through without complaint. */
3326 {
3331 field);
3336 field);
3338 {
3342 }
3343 }
3344 else
3345 {
3358 }
3367 }
3372 /* `build_class_init_list' does not recognize
3373 non-FIELD_DECLs. */
3377 }
3379 /* Check the data members (both static and non-static), class-scoped
3380 typedefs, etc., appearing in the declaration of T. Issue
3381 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3382 declaration order) of access declarations; each TREE_VALUE in this
3383 list is a USING_DECL.
3385 In addition, set the following flags:
3387 EMPTY_P
3388 The class is empty, i.e., contains no non-static data members.
3390 CANT_HAVE_CONST_CTOR_P
3391 This class cannot have an implicitly generated copy constructor
3392 taking a const reference.
3394 CANT_HAVE_CONST_ASN_REF
3395 This class cannot have an implicitly generated assignment
3396 operator taking a const reference.
3398 All of these flags should be initialized before calling this
3399 function.
3401 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3402 fields can be added by adding to this chain. */
3404 static void
3408 {
3416 /* Assume there are no access declarations. */
3418 /* Assume this class has no pointer members. */
3420 /* Assume none of the members of this class have default
3421 initializations. */
3425 {
3433 {
3434 /* Save the access declarations for our caller. */
3437 }
3444 /* FIXME: We should fold in the checking from check_methods. */
3447 /* If we've gotten this far, it's a data member, possibly static,
3448 or an enumerator. */
3452 /* When this goes into scope, it will be a non-local reference. */
3456 {
3457 /* [class.union] (C++98)
3459 If a union contains a static data member, or a member of
3460 reference type, the program is ill-formed.
3462 In C++11 [class.union] says:
3463 If a union contains a non-static data member of reference type
3464 the program is ill-formed. */
3466 {
3470 }
3473 {
3477 }
3478 }
3480 /* Perform error checking that did not get done in
3481 grokdeclarator. */
3483 {
3487 }
3489 {
3493 }
3501 /* Now it can only be a FIELD_DECL. */
3506 /* If at least one non-static data member is non-literal, the whole
3507 class becomes non-literal. Per Core/1453, volatile non-static
3508 data members and base classes are also not allowed.
3509 Note: if the type is incomplete we will complain later on. */
3514 /* A standard-layout class is a class that:
3515 ...
3516 has the same access control (Clause 11) for all non-static data members,
3517 ... */
3524 /* If this is of reference type, check if it needs an init. */
3526 {
3532 {
3533 /* ARM $12.6.2: [A member initializer list] (or, for an
3534 aggregate, initialization by a brace-enclosed list) is the
3535 only way to initialize nonstatic const and reference
3536 members. */
3539 }
3540 }
3545 {
3547 {
3548 warning_at
3551 x);
3553 }
3557 }
3561 /* We don't treat zero-width bitfields as making a class
3562 non-empty. */
3563 ;
3564 else
3565 {
3566 /* The class is non-empty. */
3568 /* The class is not even nearly empty. */
3570 /* If one of the data members contains an empty class,
3571 so does T. */
3575 }
3577 /* This is used by -Weffc++ (see below). Warn only for pointers
3578 to members which might hold dynamic memory. So do not warn
3579 for pointers to functions or pointers to members. */
3585 {
3590 }
3596 {
3598 {
3602 }
3604 {
3608 }
3609 }
3612 /* DR 148 now allows pointers to members (which are POD themselves),
3613 to be allowed in POD structs. */
3622 /* We set DECL_C_BIT_FIELD in grokbitfield.
3623 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3628 {
3633 }
3635 /* Now that we've removed bit-field widths from DECL_INITIAL,
3636 anything left in DECL_INITIAL is an NSDMI that makes the class
3637 non-aggregate in C++11. */
3641 /* If any field is const, the structure type is pseudo-const. */
3643 {
3648 {
3649 /* ARM $12.6.2: [A member initializer list] (or, for an
3650 aggregate, initialization by a brace-enclosed list) is the
3651 only way to initialize nonstatic const and reference
3652 members. */
3655 }
3656 }
3657 /* A field that is pseudo-const makes the structure likewise. */
3659 {
3664 }
3666 /* Core issue 80: A nonstatic data member is required to have a
3667 different name from the class iff the class has a
3668 user-declared constructor. */
3673 }
3675 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3676 it should also define a copy constructor and an assignment operator to
3677 implement the correct copy semantic (deep vs shallow, etc.). As it is
3678 not feasible to check whether the constructors do allocate dynamic memory
3679 and store it within members, we approximate the warning like this:
3681 -- Warn only if there are members which are pointers
3682 -- Warn only if there is a non-trivial constructor (otherwise,
3683 there cannot be memory allocated).
3684 -- Warn only if there is a non-trivial destructor. We assume that the
3685 user at least implemented the cleanup correctly, and a destructor
3686 is needed to free dynamic memory.
3688 This seems enough for practical purposes. */
3690 && has_pointers
3694 {
3698 {
3703 }
3707 }
3709 /* Non-static data member initializers make the default constructor
3710 non-trivial. */
3712 {
3715 }
3717 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3721 /* Check anonymous struct/anonymous union fields. */
3724 /* We've built up the list of access declarations in reverse order.
3725 Fix that now. */
3727 }
3729 /* If TYPE is an empty class type, records its OFFSET in the table of
3730 OFFSETS. */
3732 static int
3734 {
3735 splay_tree_node n;
3740 /* Record the location of this empty object in OFFSETS. */
3748 type,
3752 }
3754 /* Returns nonzero if TYPE is an empty class type and there is
3755 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3757 static int
3759 {
3760 splay_tree_node n;
3761 tree t;
3766 /* Record the location of this empty object in OFFSETS. */
3776 }
3778 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3779 F for every subobject, passing it the type, offset, and table of
3780 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3781 be traversed.
3783 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3784 than MAX_OFFSET will not be walked.
3786 If F returns a nonzero value, the traversal ceases, and that value
3787 is returned. Otherwise, returns zero. */
3789 static int
3791 subobject_offset_fn f,
3792 tree offset,
3793 splay_tree offsets,
3794 tree max_offset,
3796 {
3800 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3801 stop. */
3809 {
3812 }
3815 {
3816 tree field;
3817 tree binfo;
3820 /* Avoid recursing into objects that are not interesting. */
3824 /* Record the location of TYPE. */
3829 /* Iterate through the direct base classes of TYPE. */
3833 {
3834 tree binfo_offset;
3839 tree orig_binfo;
3840 /* We cannot rely on BINFO_OFFSET being set for the base
3841 class yet, but the offsets for direct non-virtual
3842 bases can be calculated by going back to the TYPE. */
3845 offset,
3849 f,
3850 binfo_offset,
3851 offsets,
3852 max_offset,
3856 }
3859 {
3863 /* Iterate through the virtual base classes of TYPE. In G++
3864 3.2, we included virtual bases in the direct base class
3865 loop above, which results in incorrect results; the
3866 correct offsets for virtual bases are only known when
3867 working with the most derived type. */
3871 {
3873 f,
3875 offset,
3877 offsets,
3878 max_offset,
3882 }
3883 else
3884 {
3885 /* We still have to walk the primary base, if it is
3886 virtual. (If it is non-virtual, then it was walked
3887 above.) */
3893 {
3894 r = (walk_subobject_offsets
3899 }
3900 }
3901 }
3903 /* Iterate through the fields of TYPE. */
3908 {
3909 tree field_offset;
3914 f,
3916 offset,
3917 field_offset),
3918 offsets,
3919 max_offset,
3923 }
3924 }
3926 {
3929 tree index;
3931 /* Avoid recursing into objects that are not interesting. */
3934 || !domain
3938 /* Step through each of the elements in the array. */
3942 {
3944 f,
3945 offset,
3946 offsets,
3947 max_offset,
3953 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3954 there's no point in iterating through the remaining
3955 elements of the array. */
3958 }
3959 }
3962 }
3964 /* Record all of the empty subobjects of TYPE (either a type or a
3965 binfo). If IS_DATA_MEMBER is true, then a non-static data member
3966 is being placed at OFFSET; otherwise, it is a base class that is
3967 being placed at OFFSET. */
3969 static void
3971 tree offset,
3972 splay_tree offsets,
3974 {
3975 tree max_offset;
3976 /* If recording subobjects for a non-static data member or a
3977 non-empty base class , we do not need to record offsets beyond
3978 the size of the biggest empty class. Additional data members
3979 will go at the end of the class. Additional base classes will go
3980 either at offset zero (if empty, in which case they cannot
3981 overlap with offsets past the size of the biggest empty class) or
3982 at the end of the class.
3984 However, if we are placing an empty base class, then we must record
3985 all offsets, as either the empty class is at offset zero (where
3986 other empty classes might later be placed) or at the end of the
3987 class (where other objects might then be placed, so other empty
3988 subobjects might later overlap). */
3992 else
3996 }
3998 /* Returns nonzero if any of the empty subobjects of TYPE (located at
3999 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4000 virtual bases of TYPE are examined. */
4002 static int
4004 tree offset,
4005 splay_tree offsets,
4007 {
4008 splay_tree_node max_node;
4010 /* Get the node in OFFSETS that indicates the maximum offset where
4011 an empty subobject is located. */
4013 /* If there aren't any empty subobjects, then there's no point in
4014 performing this check. */
4020 vbases_p);
4021 }
4023 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4024 non-static data member of the type indicated by RLI. BINFO is the
4025 binfo corresponding to the base subobject, OFFSETS maps offsets to
4026 types already located at those offsets. This function determines
4027 the position of the DECL. */
4029 static void
4031 tree decl,
4032 tree binfo,
4033 splay_tree offsets)
4034 {
4037 tree type;
4040 {
4041 /* For the purposes of determining layout conflicts, we want to
4042 use the class type of BINFO; TREE_TYPE (DECL) will be the
4043 CLASSTYPE_AS_BASE version, which does not contain entries for
4044 zero-sized bases. */
4047 }
4048 else
4049 {
4052 }
4054 /* Try to place the field. It may take more than one try if we have
4055 a hard time placing the field without putting two objects of the
4056 same type at the same address. */
4058 {
4061 /* Place this field. */
4065 /* We have to check to see whether or not there is already
4066 something of the same type at the offset we're about to use.
4067 For example, consider:
4069 struct S {};
4070 struct T : public S { int i; };
4071 struct U : public S, public T {};
4073 Here, we put S at offset zero in U. Then, we can't put T at
4074 offset zero -- its S component would be at the same address
4075 as the S we already allocated. So, we have to skip ahead.
4076 Since all data members, including those whose type is an
4077 empty class, have nonzero size, any overlap can happen only
4078 with a direct or indirect base-class -- it can't happen with
4079 a data member. */
4080 /* In a union, overlap is permitted; all members are placed at
4081 offset zero. */
4086 {
4087 /* Strip off the size allocated to this field. That puts us
4088 at the first place we could have put the field with
4089 proper alignment. */
4092 /* Bump up by the alignment required for the type. */
4093 rli->bitpos
4099 }
4102 {
4103 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4104 the offset wasn't aligned like a pointer when we started to
4105 layout this field, that affects its position. */
4108 {
4111 "alignment of %qD increased in -fabi-version=9 "
4113 else
4116 }
4118 }
4119 else
4120 /* There was no conflict. We're done laying out this field. */
4122 }
4124 /* Now that we know where it will be placed, update its
4125 BINFO_OFFSET. */
4127 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4128 this point because their BINFO_OFFSET is copied from another
4129 hierarchy. Therefore, we may not need to add the entire
4130 OFFSET. */
4136 }
4138 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4140 static int
4142 tree offset,
4144 {
4146 }
4148 /* Layout the empty base BINFO. EOC indicates the byte currently just
4149 past the end of the class, and should be correctly aligned for a
4150 class of the type indicated by BINFO; OFFSETS gives the offsets of
4151 the empty bases allocated so far. T is the most derived
4152 type. Return nonzero iff we added it at the end. */
4154 static bool
4157 {
4158 tree alignment;
4162 /* This routine should only be used for empty classes. */
4167 propagate_binfo_offsets
4171 /* This is an empty base class. We first try to put it at offset
4172 zero. */
4175 offsets,
4177 {
4178 /* That didn't work. Now, we move forward from the next
4179 available spot in the class. */
4183 {
4186 offsets,
4188 /* We finally found a spot where there's no overlap. */
4191 /* There's overlap here, too. Bump along to the next spot. */
4193 }
4194 }
4197 {
4202 }
4205 }
4207 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4208 fields at NEXT_FIELD, and return it. */
4210 static tree
4212 {
4213 /* Create the FIELD_DECL. */
4221 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4223 else
4224 {
4227 }
4233 /* Add the new FIELD_DECL to the list of fields for T. */
4239 }
4241 /* Layout the base given by BINFO in the class indicated by RLI.
4242 *BASE_ALIGN is a running maximum of the alignments of
4243 any base class. OFFSETS gives the location of empty base
4244 subobjects. T is the most derived type. Return nonzero if the new
4245 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4246 *NEXT_FIELD, unless BINFO is for an empty base class.
4248 Returns the location at which the next field should be inserted. */
4253 {
4258 /* This error is now reported in xref_tag, thus giving better
4259 location information. */
4262 /* Place the base class. */
4264 {
4265 tree decl;
4267 /* The containing class is non-empty because it has a non-empty
4268 base class. */
4271 /* Create the FIELD_DECL. */
4274 /* Try to place the field. It may take more than one try if we
4275 have a hard time placing the field without putting two
4276 objects of the same type at the same address. */
4278 }
4279 else
4280 {
4281 tree eoc;
4284 /* On some platforms (ARM), even empty classes will not be
4285 byte-aligned. */
4290 /* A nearly-empty class "has no proper base class that is empty,
4291 not morally virtual, and at an offset other than zero." */
4293 {
4296 /* The check above (used in G++ 3.2) is insufficient because
4297 an empty class placed at offset zero might itself have an
4298 empty base at a nonzero offset. */
4300 empty_base_at_nonzero_offset_p,
4301 size_zero_node,
4306 }
4308 /* We used to not create a FIELD_DECL for empty base classes because of
4309 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4310 be a problem anymore. We need them to handle initialization of C++17
4311 aggregate bases. */
4313 {
4318 }
4320 /* An empty virtual base causes a class to be non-empty
4321 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4322 here because that was already done when the virtual table
4323 pointer was created. */
4324 }
4326 /* Record the offsets of BINFO and its base subobjects. */
4329 offsets,
4333 }
4335 /* Layout all of the non-virtual base classes. Record empty
4336 subobjects in OFFSETS. T is the most derived type. Return nonzero
4337 if the type cannot be nearly empty. The fields created
4338 corresponding to the base classes will be inserted at
4339 *NEXT_FIELD. */
4341 static void
4344 {
4345 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4346 subobjects. */
4351 /* The primary base class is always allocated first. */
4356 /* Now allocate the rest of the bases. */
4358 {
4359 tree base_binfo;
4363 /* The primary base was already allocated above, so we don't
4364 need to allocate it again here. */
4368 /* Virtual bases are added at the end (a primary virtual base
4369 will have already been added). */
4375 }
4376 }
4378 /* Go through the TYPE_FIELDS of T issuing any appropriate
4379 diagnostics, figuring out which methods override which other
4380 methods, and so forth. */
4382 static void
4384 {
4387 {
4393 /* The name of the field is the original field name
4394 Save this in auxiliary field for later overloading. */
4396 {
4400 }
4402 /* All user-provided destructors are non-trivial.
4403 Constructors and assignment ops are handled in
4404 grok_special_member_properties. */
4411 "%<transaction_safe_dynamic%> may only be specified for "
4413 }
4414 }
4416 /* FN is a constructor or destructor. Clone the declaration to create
4417 a specialized in-charge or not-in-charge version, as indicated by
4418 NAME. */
4420 static tree
4422 {
4423 tree parms;
4424 tree clone;
4426 /* Copy the function. */
4428 /* Reset the function name. */
4430 /* Remember where this function came from. */
4432 /* Make it easy to find the CLONE given the FN. */
4436 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4438 {
4445 }
4446 else
4447 {
4448 // Clone constraints.
4452 }
4457 /* There's no pending inline data for this function. */
4461 /* The base-class destructor is not virtual. */
4463 {
4467 }
4473 /* If there was an in-charge parameter, drop it from the function
4474 type. */
4476 {
4479 /* Skip the `this' parameter. */
4481 /* Skip the in-charge parameter. */
4483 /* And the VTT parm, in a complete [cd]tor. */
4488 {
4489 /* If we're omitting inherited parms, that just leaves the VTT. */
4492 }
4496 parmtypes);
4502 }
4504 /* Copy the function parameters. */
4506 /* Remove the in-charge parameter. */
4508 {
4512 }
4513 /* And the VTT parm, in a complete [cd]tor. */
4515 {
4518 else
4519 {
4523 }
4524 }
4526 /* A base constructor inheriting from a virtual base doesn't get the
4527 arguments. */
4532 {
4535 }
4537 /* Create the RTL for this function. */
4542 }
4544 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4545 not invoke this function directly.
4547 For a non-thunk function, returns the address of the slot for storing
4548 the function it is a clone of. Otherwise returns NULL_TREE.
4550 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4551 cloned_function is unset. This is to support the separate
4552 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4553 on a template makes sense, but not the former. */
4555 tree *
4557 {
4565 {
4566 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4569 else
4570 #endif
4572 }
4577 else
4579 }
4581 /* Produce declarations for all appropriate clones of FN. If
4582 UPDATE_METHODS is true, the clones are added to the
4583 CLASSTYPE_MEMBER_VEC. */
4585 void
4587 {
4588 tree clone;
4590 /* Avoid inappropriate cloning. */
4596 {
4597 /* For each constructor, we need two variants: an in-charge version
4598 and a not-in-charge version. */
4605 }
4606 else
4607 {
4610 /* For each destructor, we need three variants: an in-charge
4611 version, a not-in-charge version, and an in-charge deleting
4612 version. We clone the deleting version first because that
4613 means it will go second on the TYPE_FIELDS list -- and that
4614 corresponds to the correct layout order in the virtual
4615 function table.
4617 For a non-virtual destructor, we do not build a deleting
4618 destructor. */
4620 {
4624 }
4631 }
4633 /* Note that this is an abstract function that is never emitted. */
4635 }
4637 /* DECL is an in charge constructor, which is being defined. This will
4638 have had an in class declaration, from whence clones were
4639 declared. An out-of-class definition can specify additional default
4640 arguments. As it is the clones that are involved in overload
4641 resolution, we must propagate the information from the DECL to its
4642 clones. */
4644 void
4646 {
4647 tree clone;
4651 {
4658 /* Skip the 'this' parameter. */
4674 {
4676 {
4680 }
4686 {
4687 /* A default parameter has been added. Adjust the
4688 clone's parameters. */
4692 {
4695 clone_parms);
4697 }
4700 tree type
4703 clone_parms);
4711 }
4712 }
4714 }
4715 }
4717 /* For each of the constructors and destructors in T, create an
4718 in-charge and not-in-charge variant. */
4720 static void
4722 {
4723 /* While constructors can be via a using declaration, at this point
4724 we no longer need to know that. */
4730 }
4732 /* Deduce noexcept for a destructor DTOR. */
4734 void
4736 {
4739 noexcept_deferred_spec);
4740 }
4742 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4743 of TYPE for virtual functions which FNDECL overrides. Return a
4744 mask of the tm attributes found therein. */
4746 static int
4748 {
4750 tree base_binfo;
4754 {
4762 {
4766 else
4769 }
4770 else
4772 }
4775 }
4777 /* Subroutine of set_method_tm_attributes. Handle the checks and
4778 inheritance for one virtual method FNDECL. */
4780 static void
4782 {
4783 tree tm_attr;
4788 /* If FNDECL doesn't actually override anything (i.e. T is the
4789 class that first declares FNDECL virtual), then we're done. */
4796 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4797 tm_pure must match exactly, otherwise no weakening of
4798 tm_safe > tm_callable > nothing. */
4799 /* ??? The tm_pure attribute didn't make the transition to the
4800 multivendor language spec. */
4802 {
4804 {
4807 }
4808 }
4809 /* If the overridden function is tm_pure, then FNDECL must be. */
4812 /* Look for base class combinations that cannot be satisfied. */
4814 {
4820 }
4821 /* If FNDECL did not declare an attribute, then inherit the most
4822 restrictive one. */
4824 {
4826 }
4827 /* Otherwise validate that we're not weaker than a function
4828 that is being overridden. */
4829 else
4830 {
4834 }
4837 err_override:
4841 }
4843 /* For each of the methods in T, propagate a class-level tm attribute. */
4845 static void
4847 {
4850 /* Don't bother collecting tm attributes if transactional memory
4851 support is not enabled. */
4855 /* Process virtual methods first, as they inherit directly from the
4856 base virtual function and also require validation of new attributes. */
4858 {
4859 tree vchain;
4862 {
4867 }
4868 }
4870 /* If the class doesn't have an attribute, nothing more to do. */
4875 /* Any method that does not yet have a tm attribute inherits
4876 the one from the class. */
4881 }
4883 /* Returns true if FN is a default constructor. */
4885 bool
4887 {
4890 }
4892 /* Returns true iff class T has a user-provided constructor that can be called
4893 with more than zero arguments. */
4895 bool
4897 {
4902 {
4909 }
4912 }
4914 /* Returns the defaulted constructor if T has one. Otherwise, returns
4915 NULL_TREE. */
4917 tree
4919 {
4924 {
4930 }
4933 }
4935 /* Returns true iff FN is a user-provided function, i.e. user-declared
4936 and not defaulted at its first declaration. */
4938 bool
4940 {
4943 else
4947 }
4949 /* Returns true iff class T has a user-provided constructor. */
4951 bool
4953 {
4965 }
4967 /* Returns true iff class T has a user-provided or explicit constructor. */
4969 bool
4971 {
4979 {
4983 }
4986 }
4988 /* Returns true iff class T has a non-user-provided (i.e. implicitly
4989 declared or explicitly defaulted in the class body) default
4990 constructor. */
4992 bool
4994 {
5001 {
5007 }
5010 }
5012 /* TYPE is being used as a virtual base, and has a non-trivial move
5013 assignment. Return true if this is due to there being a user-provided
5014 move assignment in TYPE or one of its subobjects; if there isn't, then
5015 multiple move assignment can't cause any harm. */
5017 bool
5019 {
5020 /* Does the type itself have a user-provided move assignment operator? */
5028 /* Do any of its bases? */
5030 tree base_binfo;
5035 /* Or non-static data members? */
5037 {
5042 }
5044 /* Seems not. */
5046 }
5048 /* If default-initialization leaves part of TYPE uninitialized, returns
5049 a DECL for the field or TYPE itself (DR 253). */
5051 tree
5053 {
5064 {
5068 }
5073 {
5077 }
5080 }
5082 /* Returns true iff for class T, a trivial synthesized default constructor
5083 would be constexpr. */
5085 bool
5087 {
5088 /* A defaulted trivial default constructor is constexpr
5089 if there is nothing to initialize. */
5092 }
5094 /* Returns true iff class T has a constexpr default constructor. */
5096 bool
5098 {
5099 tree fns;
5102 {
5103 /* The caller should have stripped an enclosing array. */
5106 }
5108 {
5111 /* Non-trivial, we need to check subobject constructors. */
5113 }
5116 }
5118 /* Returns true iff class T has a constexpr default constructor or has an
5119 implicitly declared default constructor that we can't tell if it's constexpr
5120 without forcing a lazy declaration (which might cause undesired
5121 instantiations). */
5123 bool
5125 {
5128 /* Assume it's constexpr. */
5131 }
5133 /* Returns true iff class TYPE has a virtual destructor. */
5135 bool
5137 {
5138 tree dtor;
5146 }
5148 /* Returns true iff T, a class, has a move-assignment or
5149 move-constructor. Does not lazily declare either.
5150 If USER_P is false, any move function will do. If it is true, the
5151 move function must be user-declared.
5153 Note that user-declared here is different from "user-provided",
5154 which doesn't include functions that are defaulted in the
5155 class. */
5157 bool
5159 {
5177 }
5179 /* True iff T has a move constructor that is not deleted. */
5181 bool
5183 {
5190 }
5192 /* If T, a class, has a user-provided copy constructor, copy assignment
5193 operator, or destructor, returns that function. Otherwise, null. */
5195 tree
5197 {
5200 {
5204 }
5210 {
5214 }
5217 {
5221 }
5224 }
5226 /* Nonzero if we need to build up a constructor call when initializing an
5227 object of this class, either because it has a user-declared constructor
5228 or because it doesn't have a default constructor (so we need to give an
5229 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5230 what you care about is whether or not an object can be produced by a
5231 constructor (e.g. so we don't set TREE_READONLY on const variables of
5232 such type); use this function when what you care about is whether or not
5233 to try to call a constructor to create an object. The latter case is
5234 the former plus some cases of constructors that cannot be called. */
5236 bool
5238 {
5239 tree inner;
5249 /* A user-declared constructor might be private, and a constructor might
5250 be trivial but deleted. */
5253 {
5259 }
5261 }
5263 /* Like type_build_ctor_call, but for destructors. */
5265 bool
5267 {
5268 tree inner;
5277 /* A user-declared destructor might be private, and a destructor might
5278 be trivial but deleted. */
5281 {
5287 }
5289 }
5291 /* Remove all zero-width bit-fields from T. */
5293 static void
5295 {
5300 {
5303 /* We should not be confused by the fact that grokbitfield
5304 temporarily sets the width of the bit field into
5305 DECL_BIT_FIELD_REPRESENTATIVE (*fieldsp).
5306 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5307 to that width. */
5311 else
5313 }
5314 }
5316 /* Returns TRUE iff we need a cookie when dynamically allocating an
5317 array whose elements have the indicated class TYPE. */
5319 static bool
5321 {
5322 tree fns;
5327 /* If there's a non-trivial destructor, we need a cookie. In order
5328 to iterate through the array calling the destructor for each
5329 element, we'll have to know how many elements there are. */
5333 /* If the usual deallocation function is a two-argument whose second
5334 argument is of type `size_t', then we have to pass the size of
5335 the array to the deallocation function, so we will need to store
5336 a cookie. */
5340 /* If there are no `operator []' members, or the lookup is
5341 ambiguous, then we don't need a cookie. */
5344 /* Loop through all of the functions. */
5346 {
5349 /* See if this function is a one-argument delete function. If
5350 it is, then it will be the usual deallocation function. */
5354 /* Do not consider this function if its second argument is an
5355 ellipsis. */
5358 /* Otherwise, if we have a two-argument function and the second
5359 argument is `size_t', it will be the usual deallocation
5360 function -- unless there is one-argument function, too. */
5364 }
5367 }
5369 /* Finish computing the `literal type' property of class type T.
5371 At this point, we have already processed base classes and
5372 non-static data members. We need to check whether the copy
5373 constructor is trivial, the destructor is trivial, and there
5374 is a trivial default constructor or at least one constexpr
5375 constructor other than the copy constructor. */
5377 static void
5379 {
5380 tree fn;
5392 /* C++14 DR 1684 removed this restriction. */
5400 {
5404 "enclosing class of %<constexpr%> non-static member "
5407 }
5408 }
5410 /* T is a non-literal type used in a context which requires a constant
5411 expression. Explain why it isn't literal. */
5413 void
5415 {
5425 /* Already explained. */
5431 " %qT is a closure type, which is only literal in "
5439 {
5441 " %q+T is not an aggregate, does not have a trivial "
5442 "default constructor, and has no %<constexpr%> constructor that "
5445 /* Note that we can't simply call locate_ctor because when the
5446 constructor is deleted it just returns NULL_TREE. */
5448 {
5455 {
5458 else
5461 }
5462 }
5463 }
5464 else
5465 {
5469 {
5472 {
5478 }
5479 }
5481 {
5482 tree ftype;
5487 {
5490 field);
5493 }
5497 }
5498 }
5499 }
5501 /* Check the validity of the bases and members declared in T. Add any
5502 implicitly-generated functions (like copy-constructors and
5503 assignment operators). Compute various flag bits (like
5504 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5505 level: i.e., independently of the ABI in use. */
5507 static void
5509 {
5510 /* Nonzero if the implicitly generated copy constructor should take
5511 a non-const reference argument. */
5513 /* Nonzero if the implicitly generated assignment operator
5514 should take a non-const reference argument. */
5516 tree access_decls;
5519 tree fn;
5521 /* By default, we use const reference arguments and generate default
5522 constructors. */
5526 /* Check all the base-classes and set FMEM members to point to arrays
5527 of potential interest. */
5530 /* Deduce noexcept on destructor. This needs to happen after we've set
5531 triviality flags appropriately for our bases. */
5536 /* Check all the method declarations. */
5539 /* Save the initial values of these flags which only indicate whether
5540 or not the class has user-provided functions. As we analyze the
5541 bases and members we can set these flags for other reasons. */
5545 /* Check all the data member declarations. We cannot call
5546 check_field_decls until we have called check_bases check_methods,
5547 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5548 being set appropriately. */
5553 /* A nearly-empty class has to be vptr-containing; a nearly empty
5554 class contains just a vptr. */
5558 /* Do some bookkeeping that will guide the generation of implicitly
5559 declared member functions. */
5562 /* We need to call a constructor for this class if it has a
5563 user-provided constructor, or if the default constructor is going
5564 to initialize the vptr. (This is not an if-and-only-if;
5565 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5566 themselves need constructing.) */
5569 /* [dcl.init.aggr]
5571 An aggregate is an array or a class with no user-provided
5572 constructors ... and no virtual functions.
5574 Again, other conditions for being an aggregate are checked
5575 elsewhere. */
5581 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5582 retain the old definition internally for ABI reasons. */
5591 /* If the only explicitly declared default constructor is user-provided,
5592 set TYPE_HAS_COMPLEX_DFLT. */
5598 /* Warn if a public base of a polymorphic type has an accessible
5599 non-virtual destructor. It is only now that we know the class is
5600 polymorphic. Although a polymorphic base will have a already
5601 been diagnosed during its definition, we warn on use too. */
5603 {
5606 tree base_binfo;
5610 {
5618 basetype);
5619 }
5620 }
5622 /* If the class has no user-declared constructor, but does have
5623 non-static const or reference data members that can never be
5624 initialized, issue a warning. */
5626 /* Classes with user-declared constructors are presumed to
5627 initialize these members. */
5629 /* Aggregates can be initialized with brace-enclosed
5630 initializers. */
5632 {
5633 tree field;
5636 {
5637 tree type;
5654 }
5655 }
5657 /* Synthesize any needed methods. */
5659 cant_have_const_ctor,
5660 no_const_asn_ref);
5662 /* Check defaulted declarations here so we have cant_have_const_ctor
5663 and don't need to worry about clones. */
5668 {
5671 {
5672 bool imp_const_p
5678 /* If the function is defaulted outside the class, we just
5679 give the synthesis error. Core Issue #1331 says this is
5680 no longer ill-formed, it is defined as deleted instead. */
5682 }
5684 }
5687 {
5688 /* "This class type is not an aggregate." */
5690 }
5692 /* Compute the 'literal type' property before we
5693 do anything with non-static member functions. */
5696 /* Create the in-charge and not-in-charge variants of constructors
5697 and destructors. */
5700 /* Process the using-declarations. */
5704 /* Figure out whether or not we will need a cookie when dynamically
5705 allocating an array of this type. */
5708 }
5710 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5711 accordingly. If a new vfield was created (because T doesn't have a
5712 primary base class), then the newly created field is returned. It
5713 is not added to the TYPE_FIELDS list; it is the caller's
5714 responsibility to do that. Accumulate declared virtual functions
5715 on VIRTUALS_P. */
5717 static tree
5719 {
5720 tree fn;
5722 /* Collect the virtual functions declared in T. */
5727 {
5736 }
5738 /* If we couldn't find an appropriate base class, create a new field
5739 here. Even if there weren't any new virtual functions, we might need a
5740 new virtual function table if we're supposed to include vptrs in
5741 all classes that need them. */
5743 {
5744 /* We build this decl with vtbl_ptr_type_node, which is a
5745 `vtable_entry_type*'. It might seem more precise to use
5746 `vtable_entry_type (*)[N]' where N is the number of virtual
5747 functions. However, that would require the vtable pointer in
5748 base classes to have a different type than the vtable pointer
5749 in derived classes. We could make that happen, but that
5750 still wouldn't solve all the problems. In particular, the
5751 type-based alias analysis code would decide that assignments
5752 to the base class vtable pointer can't alias assignments to
5753 the derived class vtable pointer, since they have different
5754 types. Thus, in a derived class destructor, where the base
5755 class constructor was inlined, we could generate bad code for
5756 setting up the vtable pointer.
5758 Therefore, we use one type for all vtable pointers. We still
5759 use a type-correct type; it's just doesn't indicate the array
5760 bounds. That's better than using `void*' or some such; it's
5761 cleaner, and it let's the alias analysis code know that these
5762 stores cannot alias stores to void*! */
5763 tree field;
5776 /* This class is non-empty. */
5780 }
5783 }
5785 /* Add OFFSET to all base types of BINFO which is a base in the
5786 hierarchy dominated by T.
5788 OFFSET, which is a type offset, is number of bytes. */
5790 static void
5792 {
5794 tree primary_binfo;
5795 tree base_binfo;
5797 /* Update BINFO's offset. */
5802 offset));
5804 /* Find the primary base class. */
5810 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5811 downwards. */
5813 {
5814 /* Don't do the primary base twice. */
5822 }
5823 }
5825 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5826 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5827 empty subobjects of T. */
5829 static void
5831 {
5832 tree vbase;
5839 /* Find the last field. The artificial fields created for virtual
5840 bases will go after the last extant field to date. */
5845 /* Go through the virtual bases, allocating space for each virtual
5846 base that is not already a primary base class. These are
5847 allocated in inheritance graph order. */
5849 {
5854 {
5855 /* This virtual base is not a primary base of any class in the
5856 hierarchy, so we have to add space for it. */
5859 }
5860 }
5861 }
5863 /* Returns the offset of the byte just past the end of the base class
5864 BINFO. */
5866 static tree
5868 {
5869 tree size;
5874 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5875 allocate some space for it. It cannot have virtual bases, so
5876 TYPE_SIZE_UNIT is fine. */
5878 else
5882 }
5884 /* Returns the offset of the byte just past the end of the base class
5885 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
5886 only non-virtual bases are included. */
5888 static tree
5890 {
5893 tree binfo;
5894 tree base_binfo;
5895 tree offset;
5900 {
5910 }
5915 {
5919 }
5922 }
5924 /* Warn about bases of T that are inaccessible because they are
5925 ambiguous. For example:
5927 struct S {};
5928 struct T : public S {};
5929 struct U : public S, public T {};
5931 Here, `(S*) new U' is not allowed because there are two `S'
5932 subobjects of U. */
5934 static void
5936 {
5939 tree basetype;
5940 tree binfo;
5941 tree base_binfo;
5943 /* If there are no repeated bases, nothing can be ambiguous. */
5947 /* Check direct bases. */
5950 {
5956 }
5958 /* Check for ambiguous virtual bases. */
5962 {
5968 }
5969 }
5971 /* Compare two INTEGER_CSTs K1 and K2. */
5973 static int
5975 {
5977 }
5979 /* Increase the size indicated in RLI to account for empty classes
5980 that are "off the end" of the class. */
5982 static void
5984 {
5985 tree eoc;
5986 tree rli_size;
5988 /* It might be the case that we grew the class to allocate a
5989 zero-sized base class. That won't be reflected in RLI, yet,
5990 because we are willing to overlay multiple bases at the same
5991 offset. However, now we need to make sure that RLI is big enough
5992 to reflect the entire class. */
5997 {
5998 /* The size should have been rounded to a whole byte. */
6001 rli->bitpos
6010 }
6011 }
6013 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
6014 BINFO_OFFSETs for all of the base-classes. Position the vtable
6015 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
6017 static void
6019 {
6020 tree non_static_data_members;
6021 tree field;
6022 tree vptr;
6023 record_layout_info rli;
6024 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6025 types that appear at that offset. */
6026 splay_tree empty_base_offsets;
6027 /* True if the last field laid out was a bit-field. */
6029 /* The location at which the next field should be inserted. */
6032 /* Keep track of the first non-static data member. */
6035 /* Start laying out the record. */
6038 /* Mark all the primary bases in the hierarchy. */
6041 /* Create a pointer to our virtual function table. */
6044 /* The vptr is always the first thing in the class. */
6046 {
6051 }
6052 else
6055 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6060 /* Layout the non-static data members. */
6062 {
6063 tree type;
6064 tree padding;
6066 /* We still pass things that aren't non-static data members to
6067 the back end, in case it wants to do something with them. */
6069 {
6071 /* If the static data member has incomplete type, keep track
6072 of it so that it can be completed later. (The handling
6073 of pending statics in finish_record_layout is
6074 insufficient; consider:
6076 struct S1;
6077 struct S2 { static S1 s1; };
6079 At this point, finish_record_layout will be called, but
6080 S1 is still incomplete.) */
6082 {
6084 /* The visibility of static data members is determined
6085 at their point of declaration, not their point of
6086 definition. */
6088 }
6090 }
6098 /* If this field is a bit-field whose width is greater than its
6099 type, then there are some special rules for allocating
6100 it. */
6103 {
6105 /* We must allocate the bits as if suitably aligned for the
6106 longest integer type that fits in this many bits. Then,
6107 we are supposed to use the left over bits as additional
6108 padding. */
6110 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6118 {
6120 /* Too big, so our current guess is what we want. */
6122 /* Not bigger than limit, ok */
6124 }
6126 /* Figure out how much additional padding is required. */
6128 /* In a union, the padding field must have the full width
6129 of the bit-field; all fields start at offset zero. */
6131 else
6138 /* An unnamed bitfield does not normally affect the
6139 alignment of the containing class on a target where
6140 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6141 make any exceptions for unnamed bitfields when the
6142 bitfields are longer than their types. Therefore, we
6143 temporarily give the field a name. */
6145 {
6148 }
6154 empty_base_offsets);
6157 /* Now that layout has been performed, set the size of the
6158 field to the size of its declared type; the rest of the
6159 field is effectively invisible. */
6161 /* We must also reset the DECL_MODE of the field. */
6163 }
6164 else
6166 empty_base_offsets);
6168 /* Remember the location of any empty classes in FIELD. */
6171 empty_base_offsets,
6174 /* If a bit-field does not immediately follow another bit-field,
6175 and yet it starts in the middle of a byte, we have failed to
6176 comply with the ABI. */
6179 /* The TREE_NO_WARNING flag gets set by Objective-C when
6180 laying out an Objective-C class. The ObjC ABI differs
6181 from the C++ ABI, and so we do not want a warning
6182 here. */
6184 && !last_field_was_bitfield
6187 bitsize_unit_node)))
6189 "offset of %qD is not ABI-compliant and may "
6192 /* The middle end uses the type of expressions to determine the
6193 possible range of expression values. In order to optimize
6194 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6195 must be made aware of the width of "i", via its type.
6197 Because C++ does not have integer types of arbitrary width,
6198 we must (for the purposes of the front end) convert from the
6199 type assigned here to the declared type of the bitfield
6200 whenever a bitfield expression is used as an rvalue.
6201 Similarly, when assigning a value to a bitfield, the value
6202 must be converted to the type given the bitfield here. */
6204 {
6209 {
6216 }
6217 }
6219 /* If we needed additional padding after this field, add it
6220 now. */
6222 {
6223 tree padding_field;
6226 FIELD_DECL,
6227 NULL_TREE,
6228 char_type_node);
6236 NULL_TREE,
6237 empty_base_offsets);
6238 }
6241 }
6244 {
6245 /* Make sure that we are on a byte boundary so that the size of
6246 the class without virtual bases will always be a round number
6247 of bytes. */
6250 }
6252 /* Delete all zero-width bit-fields from the list of fields. Now
6253 that the type is laid out they are no longer important. */
6257 {
6258 /* T needs a different layout as a base (eliding virtual bases
6259 or whatever). Create that version. */
6262 /* If the ABI version is not at least two, and the last
6263 field was a bit-field, RLI may not be on a byte
6264 boundary. In particular, rli_size_unit_so_far might
6265 indicate the last complete byte, while rli_size_so_far
6266 indicates the total number of bits used. Therefore,
6267 rli_size_so_far, rather than rli_size_unit_so_far, is
6268 used to compute TYPE_SIZE_UNIT. */
6276 eoc);
6287 /* Copy the non-static data members of T. This will include its
6288 direct non-virtual bases & vtable. */
6292 {
6296 }
6299 /* We use the base type for trivial assignments, and hence it
6300 needs a mode. */
6305 /* Record the base version of the type. */
6307 }
6308 else
6311 /* Every empty class contains an empty class. */
6315 /* Set the TYPE_DECL for this type to contain the right
6316 value for DECL_OFFSET, so that we can use it as part
6317 of a COMPONENT_REF for multiple inheritance. */
6320 /* Now fix up any virtual base class types that we left lying
6321 around. We must get these done before we try to lay out the
6322 virtual function table. As a side-effect, this will remove the
6323 base subobject fields. */
6326 /* Make sure that empty classes are reflected in RLI at this
6327 point. */
6330 /* Make sure not to create any structures with zero size. */
6336 /* If this is a non-POD, declaring it packed makes a difference to how it
6337 can be used as a field; don't let finalize_record_size undo it. */
6341 /* Let the back end lay out the type. */
6350 /* Warn about bases that can't be talked about due to ambiguity. */
6353 /* Now that we're done with layout, give the base fields the real types. */
6358 /* Clean up. */
6365 }
6367 /* Determine the "key method" for the class type indicated by TYPE,
6368 and set CLASSTYPE_KEY_METHOD accordingly. */
6370 void
6372 {
6373 tree method;
6380 /* The key method is the first non-pure virtual function that is not
6381 inline at the point of class definition. On some targets the
6382 key function may not be inline; those targets should not call
6383 this function until the end of the translation unit. */
6389 {
6392 }
6395 }
6397 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6398 class data member of non-zero size, otherwise false. */
6402 {
6410 {
6414 }
6417 }
6419 /* Used by find_flexarrays and related functions. */
6421 struct flexmems_t
6422 {
6423 /* The first flexible array member or non-zero array member found
6424 in the order of layout. */
6425 tree array;
6426 /* First non-static non-empty data member in the class or its bases. */
6427 tree first;
6428 /* The first non-static non-empty data member following either
6429 the flexible array member, if found, or the zero-length array member
6430 otherwise. AFTER[1] refers to the first such data member of a union
6431 of which the struct containing the flexible array member or zero-length
6432 array is a member, or NULL when no such union exists. This element is
6433 only used during searching, not for diagnosing problems. AFTER[0]
6434 refers to the first such data member that is not a member of such
6435 a union. */
6438 /* Refers to a struct (not union) in which the struct of which the flexible
6439 array is member is defined. Used to diagnose strictly (according to C)
6440 invalid uses of the latter structs. */
6441 tree enclosing;
6442 };
6444 /* Find either the first flexible array member or the first zero-length
6445 array, in that order of preference, among members of class T (but not
6446 its base classes), and set members of FMEM accordingly.
6447 BASE_P is true if T is a base class of another class.
6448 PUN is set to the outermost union in which the flexible array member
6449 (or zero-length array) is defined if one such union exists, otherwise
6450 to NULL.
6451 Similarly, PSTR is set to a data member of the outermost struct of
6452 which the flexible array is a member if one such struct exists,
6453 otherwise to NULL. */
6455 static void
6459 {
6460 /* Set the "pointer" to the outermost enclosing union if not set
6461 yet and maintain it for the remainder of the recursion. */
6466 {
6470 /* Is FLD a typedef for an anonymous struct? */
6472 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6473 handled elsewhere so that errors like the following are detected
6474 as well:
6475 typedef struct { int i, a[], j; } S; // bug c++/72753
6476 S s [2]; // bug c++/68489
6477 */
6482 {
6483 /* Check the nested unnamed type referenced via a typedef
6484 independently of FMEM (since it's not a data member of
6485 the enclosing class). */
6488 }
6490 /* Skip anything that's GCC-generated or not a (non-static) data
6491 member. */
6495 /* Type of the member. */
6500 /* Determine the type of the array element or object referenced
6501 by the member so that it can be checked for flexible array
6502 members if it hasn't been yet. */
6509 {
6511 {
6512 /* Once the member after the flexible array has been found
6513 we're done. */
6516 }
6519 {
6520 /* Descend into the non-static member struct or union and try
6521 to find a flexible array member or zero-length array among
6522 its members. This is only necessary for anonymous types
6523 and types in whose context the current type T has not been
6524 defined (the latter must not be checked again because they
6525 are already in the process of being checked by one of the
6526 recursive calls). */
6531 /* If this member isn't anonymous and a prior non-flexible array
6532 member has been seen in one of the enclosing structs, clear
6533 the FIRST member since it doesn't contribute to the flexible
6534 array struct's members. */
6545 {
6546 /* Restore the FIRST member reset above if no flexible
6547 array member has been found in this member's struct. */
6549 }
6551 /* If the member struct contains the first flexible array
6552 member, or if this member is a base class, continue to
6553 the next member and avoid setting the FMEM->NEXT pointer
6554 to point to it. */
6557 }
6558 }
6561 {
6562 /* Remember the first non-static data member. */
6566 /* Remember the first non-static data member after the flexible
6567 array member, if one has been found, or the zero-length array
6568 if it has been found. */
6571 }
6573 /* Skip non-arrays. */
6577 /* Determine the upper bound of the array if it has one. */
6579 {
6581 {
6582 /* Make a record of the zero-length array if either one
6583 such field or a flexible array member has been seen to
6584 handle the pathological and unlikely case of multiple
6585 such members. */
6588 }
6590 {
6591 /* Remember the first zero-length array unless a flexible array
6592 member has already been seen. */
6595 }
6596 }
6597 else
6598 {
6599 /* Flexible array members have no upper bound. */
6601 {
6603 {
6604 /* Replace the zero-length array if it's been stored and
6605 reset the after pointer. */
6609 }
6611 /* Make a record of another flexible array member. */
6613 }
6614 else
6615 {
6618 }
6619 }
6620 }
6621 }
6623 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6624 a flexible array member (or the zero-length array extension). */
6626 static void
6628 {
6640 }
6642 /* Issue diagnostics for invalid flexible array members or zero-length
6643 arrays that are not the last elements of the containing class or its
6644 base classes or that are its sole members. */
6646 static void
6648 {
6653 {
6656 }
6658 /* Has a diagnostic been issued? */
6664 {
6671 {
6675 {
6678 }
6679 }
6680 }
6681 else
6682 {
6689 {
6695 /* In the unlikely event that the member following the flexible
6696 array member is declared in a different class, or the member
6697 overlaps another member of a common union, point to it.
6698 Otherwise it should be obvious. */
6702 {
6707 }
6708 }
6709 }
6713 }
6716 /* Recursively check to make sure that any flexible array or zero-length
6717 array members of class T or its bases are valid (i.e., not the sole
6718 non-static data member of T and, if one exists, that it is the last
6719 non-static data member of T and its base classes. FMEM is expected
6720 to be initially null and is used internally by recursive calls to
6721 the function. Issue the appropriate diagnostics for the array member
6722 that fails the checks. */
6724 static void
6727 {
6728 /* Initialize the result of a search for flexible array and zero-length
6729 array members. Avoid doing any work if the most interesting FMEM data
6730 have already been populated. */
6739 /* Recursively check the primary base class first. */
6741 {
6744 }
6746 /* Recursively check the base classes. */
6749 {
6752 /* The primary base class was already checked above. */
6756 /* Virtual base classes are at the end. */
6760 /* Check the base class. */
6762 }
6765 {
6766 /* Check virtual base classes only once per derived class.
6767 I.e., this check is not performed recursively for base
6768 classes. */
6770 tree base_binfo;
6774 {
6775 /* Check the virtual base class. */
6779 }
6780 }
6782 /* Is the type unnamed (and therefore a member of it potentially
6783 an anonymous struct or union)? */
6786 /* Search the members of the current (possibly derived) class, skipping
6787 unnamed structs and unions since those could be anonymous. */
6792 {
6793 /* Issue diagnostics for invalid flexible and zero-length array
6794 members found in base classes or among the members of the current
6795 class. Ignore anonymous structs and unions whose members are
6796 considered to be members of the enclosing class and thus will
6797 be diagnosed when checking it. */
6799 }
6800 }
6802 /* Perform processing required when the definition of T (a class type)
6803 is complete. Diagnose invalid definitions of flexible array members
6804 and zero-size arrays. */
6806 void
6808 {
6809 tree x;
6810 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6814 {
6819 }
6821 /* If this type was previously laid out as a forward reference,
6822 make sure we lay it out again. */
6826 /* Make assumptions about the class; we'll reset the flags if
6827 necessary. */
6833 /* Do end-of-class semantic processing: checking the validity of the
6834 bases and members and add implicitly generated methods. */
6837 /* Find the key method. */
6839 {
6840 /* The Itanium C++ ABI permits the key method to be chosen when
6841 the class is defined -- even though the key method so
6842 selected may later turn out to be an inline function. On
6843 some systems (such as ARM Symbian OS) the key method cannot
6844 be determined until the end of the translation unit. On such
6845 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6846 will cause the class to be added to KEYED_CLASSES. Then, in
6847 finish_file we will determine the key method. */
6851 /* If a polymorphic class has no key method, we may emit the vtable
6852 in every translation unit where the class definition appears. If
6853 we're devirtualizing, we can look into the vtable even if we
6854 aren't emitting it. */
6857 }
6859 /* Layout the class itself. */
6861 /* COMPLETE_TYPE_P is now true. */
6865 /* With the layout complete, check for flexible array members and
6866 zero-length arrays that might overlap other members in the final
6867 layout. */
6872 /* If necessary, create the primary vtable for this class. */
6874 {
6875 /* We must enter these virtuals into the table. */
6879 /* Here we know enough to change the type of our virtual
6880 function table, but we will wait until later this function. */
6883 /* If we're warning about ABI tags, check the types of the new
6884 virtual functions. */
6888 }
6891 {
6893 tree fn;
6900 /* Add entries for virtual functions introduced by this class. */
6904 /* Set DECL_VINDEX for all functions declared in this class. */
6906 fn;
6908 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6910 {
6914 /* A thunk. We should never be calling this entry directly
6915 from this vtable -- we'd use the entry for the non
6916 thunk base function. */
6920 }
6921 }
6929 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
6930 for any static member objects of the type we're working on. */
6939 /* Complain if one of the field types requires lower visibility. */
6942 /* Make the rtl for any new vtables we have created, and unmark
6943 the base types we marked. */
6946 /* Build the VTT for T. */
6953 "%q#T has virtual functions and accessible"
6961 /* Class layout, assignment of virtual table slots, etc., is now
6962 complete. Give the back end a chance to tweak the visibility of
6963 the class or perform any other required target modifications. */
6973 /* Finish debugging output for this type. */
6977 {
6980 {
6983 }
6985 {
6988 else
6989 {
6992 }
6994 }
6996 {
6998 "the type of the first field has a different ABI from the "
7001 }
7002 }
7003 }
7005 /* When T was built up, the member declarations were added in reverse
7006 order. Rearrange them to declaration order. */
7008 void
7010 {
7011 tree next;
7012 tree prev;
7013 tree x;
7015 /* The following lists are all in reverse order. Put them in
7016 declaration order now. */
7019 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
7020 order, so we can't just use nreverse. Due to stat_hack
7021 chicanery in finish_member_declaration. */
7026 {
7030 }
7033 {
7036 }
7037 }
7039 tree
7041 {
7044 /* Now that we've got all the field declarations, reverse everything
7045 as necessary. */
7051 /* Nadger the current location so that diagnostics point to the start of
7052 the struct, not the end. */
7056 {
7057 tree x;
7059 /* We need to add the target functions of USING_DECLS, so that
7060 they can be found when the using declaration is not
7061 instantiated yet. */
7064 {
7069 }
7075 /* COMPLETE_TYPE_P is now true. */
7079 /* We need to emit an error message if this type was used as a parameter
7080 and it is an abstract type, even if it is a template. We construct
7081 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7082 account and we call complete_vars with this type, which will check
7083 the PARM_DECLS. Note that while the type is being defined,
7084 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7085 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7092 /* Remember current #pragma pack value. */
7095 /* Fix up any variants we've already built. */
7097 {
7101 }
7102 }
7103 else
7105 /* COMPLETE_TYPE_P is now true. */
7110 {
7111 /* People keep complaining that the compiler crashes on an invalid
7112 definition of initializer_list, so I guess we should explicitly
7113 reject it. What the compiler internals care about is that it's a
7114 template and has a pointer field followed by size_type field. */
7117 {
7120 {
7124 }
7125 }
7129 }
7137 else
7141 /* Lambdas are defined by the LAMBDA_EXPR. */
7146 }
7147 \f
7148 /* Hash table to avoid endless recursion when handling references. */
7151 /* Return the dynamic type of INSTANCE, if known.
7152 Used to determine whether the virtual function table is needed
7153 or not.
7155 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7156 of our knowledge of its type. *NONNULL should be initialized
7157 before this function is called. */
7159 static tree
7161 {
7162 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7165 {
7169 else
7173 /* This is a call to a constructor, hence it's never zero. */
7176 {
7180 }
7184 /* This is a call to a constructor, hence it's never zero. */
7186 {
7190 }
7199 /* Propagate nonnull. */
7204 CASE_CONVERT:
7210 {
7211 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7212 with a real object -- given &p->f, p can still be null. */
7214 /* ??? Probably should check DECL_WEAK here. */
7217 }
7221 /* If this component is really a base class reference, then the field
7222 itself isn't definitive. */
7231 {
7235 }
7236 /* fall through. */
7241 {
7245 }
7247 {
7251 /* if we're in a ctor or dtor, we know our type. If
7252 current_class_ptr is set but we aren't in a function, we're in
7253 an NSDMI (and therefore a constructor). */
7258 {
7262 }
7263 }
7265 {
7266 /* We only need one hash table because it is always left empty. */
7268 fixed_type_or_null_ref_ht
7271 /* Reference variables should be references to objects. */
7275 /* Enter the INSTANCE in a table to prevent recursion; a
7276 variable's initializer may refer to the variable
7277 itself. */
7282 {
7283 tree type;
7292 }
7293 }
7298 }
7299 #undef RECUR
7300 }
7302 /* Return nonzero if the dynamic type of INSTANCE is known, and
7303 equivalent to the static type. We also handle the case where
7304 INSTANCE is really a pointer. Return negative if this is a
7305 ctor/dtor. There the dynamic type is known, but this might not be
7306 the most derived base of the original object, and hence virtual
7307 bases may not be laid out according to this type.
7309 Used to determine whether the virtual function table is needed
7310 or not.
7312 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7313 of our knowledge of its type. *NONNULL should be initialized
7314 before this function is called. */
7316 int
7318 {
7321 tree fixed;
7323 /* processing_template_decl can be false in a template if we're in
7324 instantiate_non_dependent_expr, but we still want to suppress
7325 this check. */
7327 {
7328 /* In a template we only care about the type of the result. */
7332 }
7342 }
7344 \f
7345 void
7347 {
7350 current_class_stack
7358 }
7360 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7362 static void
7364 {
7365 tree type;
7367 /* We are re-entering the same class we just left, so we don't
7368 have to search the whole inheritance matrix to find all the
7369 decls to bind again. Instead, we install the cached
7370 class_shadowed list and walk through it binding names. */
7373 /* Restore IDENTIFIER_TYPE_VALUE. */
7375 type;
7378 }
7380 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7381 appropriate for TYPE.
7383 So that we may avoid calls to lookup_name, we cache the _TYPE
7384 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7386 For multiple inheritance, we perform a two-pass depth-first search
7387 of the type lattice. */
7389 void
7391 {
7392 class_stack_node_t csn;
7396 /* Make sure there is enough room for the new entry on the stack. */
7398 {
7400 current_class_stack
7402 current_class_stack_size);
7403 }
7405 /* Insert a new entry on the class stack. */
7412 current_class_depth++;
7414 /* Now set up the new type. */
7420 /* By default, things in classes are private, while things in
7421 structures or unions are public. */
7423 ? access_private_node
7429 {
7430 /* Forcibly remove any old class remnants. */
7432 }
7438 else
7440 }
7442 /* When we exit a toplevel class scope, we save its binding level so
7443 that we can restore it quickly. Here, we've entered some other
7444 class, so we must invalidate our cache. */
7446 void
7448 {
7450 }
7452 /* Get out of the current class scope. If we were in a class scope
7453 previously, that is the one popped to. */
7455 void
7457 {
7460 current_class_depth--;
7466 }
7468 /* Mark the top of the class stack as hidden. */
7470 void
7472 {
7475 }
7477 /* Mark the top of the class stack as un-hidden. */
7479 void
7481 {
7484 }
7486 /* If the class type currently being defined is either T or
7487 a nested type of T, returns the type from the current_class_stack,
7488 which might be equivalent to but not equal to T in case of
7489 constrained partial specializations. */
7491 tree
7493 {
7501 /* We start looking from 1 because entry 0 is from global scope,
7502 and has no type. */
7504 {
7505 tree c;
7508 else
7509 {
7513 }
7518 }
7520 }
7522 /* If either current_class_type or one of its enclosing classes are derived
7523 from T, return the appropriate type. Used to determine how we found
7524 something via unqualified lookup. */
7526 tree
7528 {
7531 /* The bases of a dependent type are unknown. */
7542 {
7547 }
7550 }
7552 /* Return the outermost enclosing class type that is still open, or
7553 NULL_TREE. */
7555 tree
7557 {
7564 {
7571 }
7573 }
7575 /* Returns the innermost class type which is not a lambda closure type. */
7577 tree
7579 {
7584 }
7586 /* When entering a class scope, all enclosing class scopes' names with
7587 static meaning (static variables, static functions, types and
7588 enumerators) have to be visible. This recursive function calls
7589 pushclass for all enclosing class contexts until global or a local
7590 scope is reached. TYPE is the enclosed class. */
7592 void
7594 {
7595 /* A namespace might be passed in error cases, like A::B:C. */
7603 }
7605 /* Undoes a push_nested_class call. */
7607 void
7609 {
7615 }
7617 /* Returns the number of extern "LANG" blocks we are nested within. */
7619 int
7621 {
7623 }
7625 /* Set global variables CURRENT_LANG_NAME to appropriate value
7626 so that behavior of name-mangling machinery is correct. */
7628 void
7630 {
7637 else
7639 }
7641 /* Get out of the current language scope. */
7643 void
7645 {
7647 }
7648 \f
7649 /* Type instantiation routines. */
7651 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7652 matches the TARGET_TYPE. If there is no satisfactory match, return
7653 error_mark_node, and issue an error & warning messages under
7654 control of FLAGS. Permit pointers to member function if FLAGS
7655 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7656 a template-id, and EXPLICIT_TARGS are the explicitly provided
7657 template arguments.
7659 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7660 is the base path used to reference those member functions. If
7661 the address is resolved to a member function, access checks will be
7662 performed and errors issued if appropriate. */
7664 static tree
7666 tree overload,
7667 tsubst_flags_t complain,
7669 tree explicit_targs,
7670 tree access_path)
7671 {
7672 /* Here's what the standard says:
7674 [over.over]
7676 If the name is a function template, template argument deduction
7677 is done, and if the argument deduction succeeds, the deduced
7678 arguments are used to generate a single template function, which
7679 is added to the set of overloaded functions considered.
7681 Non-member functions and static member functions match targets of
7682 type "pointer-to-function" or "reference-to-function." Nonstatic
7683 member functions match targets of type "pointer-to-member
7684 function;" the function type of the pointer to member is used to
7685 select the member function from the set of overloaded member
7686 functions. If a nonstatic member function is selected, the
7687 reference to the overloaded function name is required to have the
7688 form of a pointer to member as described in 5.3.1.
7690 If more than one function is selected, any template functions in
7691 the set are eliminated if the set also contains a non-template
7692 function, and any given template function is eliminated if the
7693 set contains a second template function that is more specialized
7694 than the first according to the partial ordering rules 14.5.5.2.
7695 After such eliminations, if any, there shall remain exactly one
7696 selected function. */
7699 /* We store the matches in a TREE_LIST rooted here. The functions
7700 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7701 interoperability with most_specialized_instantiation. */
7703 tree fn;
7704 tree target_fn_type;
7706 /* By the time we get here, we should be seeing only real
7707 pointer-to-member types, not the internal POINTER_TYPE to
7708 METHOD_TYPE representation. */
7714 /* Check that the TARGET_TYPE is reasonable. */
7719 /* This is OK, too. */
7722 /* This is OK, too. This comes from a conversion to reference
7723 type. */
7725 else
7726 {
7732 }
7734 /* Non-member functions and static member functions match targets of type
7735 "pointer-to-function" or "reference-to-function." Nonstatic member
7736 functions match targets of type "pointer-to-member-function;" the
7737 function type of the pointer to member is used to select the member
7738 function from the set of overloaded member functions.
7740 So figure out the FUNCTION_TYPE that we want to match against. */
7743 /* If we can find a non-template function that matches, we can just
7744 use it. There's no point in generating template instantiations
7745 if we're just going to throw them out anyhow. But, of course, we
7746 can only do this when we don't *need* a template function. */
7749 {
7753 /* We're not looking for templates just yet. */
7757 /* We're looking for a non-static member, and this isn't
7758 one, or vice versa. */
7761 /* In C++17 we need the noexcept-qualifier to compare types. */
7766 /* See if there's a match. */
7771 }
7773 /* Now, if we've already got a match (or matches), there's no need
7774 to proceed to the template functions. But, if we don't have a
7775 match we need to look at them, too. */
7777 {
7778 tree target_arg_types;
7779 tree target_ret_type;
7782 tree arg;
7796 {
7798 tree instantiation;
7799 tree targs;
7802 /* We're only looking for templates. */
7807 /* We're not looking for a non-static member, and this is
7808 one, or vice versa. */
7813 /* If the template has a deduced return type, don't expose it to
7814 template argument deduction. */
7818 /* Try to do argument deduction. */
7825 /* Instantiation failed. */
7828 /* Constraints must be satisfied. This is done before
7829 return type deduction since that instantiates the
7830 function. */
7834 /* And now force instantiation to do return type deduction. */
7836 {
7842 }
7844 /* In C++17 we need the noexcept-qualifier to compare types. */
7848 /* See if there's a match. */
7853 }
7855 /* Now, remove all but the most specialized of the matches. */
7857 {
7862 NULL_TREE,
7863 NULL_TREE);
7864 }
7865 }
7867 /* Now we should have exactly one function in MATCHES. */
7869 {
7870 /* There were *no* matches. */
7872 {
7877 }
7879 }
7881 {
7882 /* There were too many matches. First check if they're all
7883 the same function. */
7888 /* For multi-versioned functions, more than one match is just fine and
7889 decls_match will return false as they are different. */
7897 {
7899 {
7903 /* Since print_candidates expects the functions in the
7904 TREE_VALUE slot, we flip them here. */
7909 }
7912 }
7913 }
7915 /* Good, exactly one match. Now, convert it to the correct type. */
7920 {
7928 {
7932 }
7933 }
7935 /* If a pointer to a function that is multi-versioned is requested, the
7936 pointer to the dispatcher function is returned instead. This works
7937 well because indirectly calling the function will dispatch the right
7938 function version at run-time. */
7940 {
7944 /* Mark all the versions corresponding to the dispatcher as used. */
7947 }
7949 /* If we're doing overload resolution purely for the purpose of
7950 determining conversion sequences, we should not consider the
7951 function used. If this conversion sequence is selected, the
7952 function will be marked as used at this point. */
7954 {
7955 /* Make =delete work with SFINAE. */
7960 }
7962 /* We could not check access to member functions when this
7963 expression was originally created since we did not know at that
7964 time to which function the expression referred. */
7966 {
7969 }
7973 else
7974 {
7975 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
7976 will mark the function as addressed, but here we must do it
7977 explicitly. */
7981 }
7982 }
7984 /* This function will instantiate the type of the expression given in
7985 RHS to match the type of LHSTYPE. If errors exist, then return
7986 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
7987 we complain on errors. If we are not complaining, never modify rhs,
7988 as overload resolution wants to try many possible instantiations, in
7989 the hope that at least one will work.
7991 For non-recursive calls, LHSTYPE should be a function, pointer to
7992 function, or a pointer to member function. */
7994 tree
7996 {
8003 {
8007 }
8010 {
8019 /* Microsoft allows `A::f' to be resolved to a
8020 pointer-to-member. */
8021 ;
8022 else
8023 {
8028 }
8029 }
8031 /* If we instantiate a template, and it is a A ?: C expression
8032 with omitted B, look through the SAVE_EXPR. */
8037 {
8040 }
8042 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
8043 deduce any type information. */
8045 {
8049 }
8051 /* There are only a few kinds of expressions that may have a type
8052 dependent on overload resolution. */
8058 /* This should really only be used when attempting to distinguish
8059 what sort of a pointer to function we have. For now, any
8060 arithmetic operation which is not supported on pointers
8061 is rejected as an error. */
8064 {
8066 {
8072 /* Do not lose object's side effects. */
8076 }
8083 /* This can happen if we are forming a pointer-to-member for a
8084 member template. */
8087 /* Fall through. */
8090 {
8094 return
8098 }
8102 return
8106 access_path);
8109 {
8114 }
8121 }
8123 }
8124 \f
8125 /* Return the name of the virtual function pointer field
8126 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8127 this may have to look back through base types to find the
8128 ultimate field name. (For single inheritance, these could
8129 all be the same name. Who knows for multiple inheritance). */
8131 static tree
8133 {
8139 {
8145 }
8153 }
8155 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8156 according to [class]:
8157 The class-name is also inserted
8158 into the scope of the class itself. For purposes of access checking,
8159 the inserted class name is treated as if it were a public member name. */
8161 void
8163 {
8180 }
8182 /* Returns 1 if TYPE contains only padding bytes. */
8184 int
8186 {
8194 }
8196 /* Returns true if TYPE contains no actual data, just various
8197 possible combinations of empty classes and possibly a vptr. */
8199 bool
8201 {
8203 {
8204 tree field;
8205 tree binfo;
8206 tree base_binfo;
8209 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8210 out, but we'd like to be able to check this before then. */
8221 /* An unnamed bit-field is not a data member. */
8226 }
8231 }
8233 /* Note that NAME was looked up while the current class was being
8234 defined and that the result of that lookup was DECL. */
8236 void
8238 {
8239 splay_tree names_used;
8241 /* If we're not defining a class, there's nothing to do. */
8247 /* If there's already a binding for this NAME, then we don't have
8248 anything to worry about. */
8261 }
8263 /* Note that NAME was declared (as DECL) in the current class. Check
8264 to see that the declaration is valid. */
8266 void
8268 {
8269 splay_tree names_used;
8270 splay_tree_node n;
8272 /* Look to see if we ever used this name. */
8273 names_used
8277 /* The C language allows members to be declared with a type of the same
8278 name, and the C++ standard says this diagnostic is not required. So
8279 allow it in extern "C" blocks unless predantic is specified.
8280 Allow it in all cases if -ms-extensions is specified. */
8286 {
8287 /* [basic.scope.class]
8289 A name N used in a class S shall refer to the same declaration
8290 in its context and when re-evaluated in the completed scope of
8291 S. */
8298 }
8299 }
8301 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8302 Secondary vtables are merged with primary vtables; this function
8303 will return the VAR_DECL for the primary vtable. */
8305 tree
8307 {
8308 tree decl;
8312 {
8315 }
8319 }
8322 /* Returns the binfo for the primary base of BINFO. If the resulting
8323 BINFO is a virtual base, and it is inherited elsewhere in the
8324 hierarchy, then the returned binfo might not be the primary base of
8325 BINFO in the complete object. Check BINFO_PRIMARY_P or
8326 BINFO_LOST_PRIMARY_P to be sure. */
8328 static tree
8330 {
8331 tree primary_base;
8338 }
8340 /* As above, but iterate until we reach the binfo that actually provides the
8341 vptr for BINFO. */
8343 static tree
8345 {
8349 {
8354 }
8356 }
8358 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8359 type. Note that the virtual inheritance might be above or below BINFO in
8360 the hierarchy. */
8362 bool
8364 {
8368 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8369 a morally virtual base. */
8372 }
8374 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8376 static int
8378 {
8382 }
8384 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8385 INDENT should be zero when called from the top level; it is
8386 incremented recursively. IGO indicates the next expected BINFO in
8387 inheritance graph ordering. */
8389 static tree
8391 dump_flags_t flags,
8392 tree binfo,
8393 tree igo,
8395 {
8397 tree base_binfo;
8405 {
8408 }
8423 {
8427 TFF_PLAIN_IDENTIFIER),
8429 }
8431 {
8434 }
8439 {
8443 {
8447 TFF_PLAIN_IDENTIFIER));
8448 }
8450 {
8454 TFF_PLAIN_IDENTIFIER));
8455 }
8457 {
8461 TFF_PLAIN_IDENTIFIER));
8462 }
8464 {
8468 TFF_PLAIN_IDENTIFIER));
8469 }
8473 }
8479 }
8481 /* Dump the BINFO hierarchy for T. */
8483 static void
8485 {
8497 }
8499 /* Debug interface to hierarchy dumping. */
8501 void
8503 {
8505 }
8507 static void
8509 {
8510 dump_flags_t flags;
8512 {
8515 }
8516 }
8518 static void
8520 {
8521 tree value;
8523 HOST_WIDE_INT elt;
8531 TFF_PLAIN_IDENTIFIER));
8538 }
8540 static void
8542 {
8543 dump_flags_t flags;
8550 {
8557 {
8562 }
8566 }
8569 }
8571 static void
8573 {
8574 dump_flags_t flags;
8581 {
8586 }
8589 }
8591 /* Dump a function or thunk and its thunkees. */
8593 static void
8595 {
8598 tree thunks;
8606 {
8616 else
8622 }
8626 }
8628 /* Dump the thunks for FN. */
8630 void
8632 {
8634 }
8636 /* Virtual function table initialization. */
8638 /* Create all the necessary vtables for T and its base classes. */
8640 static void
8642 {
8643 tree vbase;
8647 /* We lay out the primary and secondary vtables in one contiguous
8648 vtable. The primary vtable is first, followed by the non-virtual
8649 secondary vtables in inheritance graph order. */
8653 /* Then come the virtual bases, also in inheritance graph order. */
8655 {
8659 }
8663 }
8665 /* Initialize the vtable for BINFO with the INITS. */
8667 static void
8669 {
8670 tree decl;
8676 }
8678 /* Build the VTT (virtual table table) for T.
8679 A class requires a VTT if it has virtual bases.
8681 This holds
8682 1 - primary virtual pointer for complete object T
8683 2 - secondary VTTs for each direct non-virtual base of T which requires a
8684 VTT
8685 3 - secondary virtual pointers for each direct or indirect base of T which
8686 has virtual bases or is reachable via a virtual path from T.
8687 4 - secondary VTTs for each direct or indirect virtual base of T.
8689 Secondary VTTs look like complete object VTTs without part 4. */
8691 static void
8693 {
8694 tree type;
8695 tree vtt;
8696 tree index;
8699 /* Build up the initializers for the VTT. */
8704 /* If we didn't need a VTT, we're done. */
8708 /* Figure out the type of the VTT. */
8712 /* Now, build the VTT object itself. */
8715 /* Add the VTT to the vtables list. */
8720 }
8722 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8723 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8724 and CHAIN the vtable pointer for this binfo after construction is
8725 complete. VALUE can also be another BINFO, in which case we recurse. */
8727 static tree
8729 {
8730 tree vt;
8733 {
8739 else
8741 }
8744 }
8746 /* Data for secondary VTT initialization. */
8747 struct secondary_vptr_vtt_init_data
8748 {
8749 /* Is this the primary VTT? */
8752 /* Current index into the VTT. */
8753 tree index;
8755 /* Vector of initializers built up. */
8758 /* The type being constructed by this secondary VTT. */
8759 tree type_being_constructed;
8760 };
8762 /* Recursively build the VTT-initializer for BINFO (which is in the
8763 hierarchy dominated by T). INITS points to the end of the initializer
8764 list to date. INDEX is the VTT index where the next element will be
8765 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8766 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8767 for virtual bases of T. When it is not so, we build the constructor
8768 vtables for the BINFO-in-T variant. */
8770 static void
8773 {
8775 tree b;
8776 tree init;
8777 secondary_vptr_vtt_init_data data;
8780 /* We only need VTTs for subobjects with virtual bases. */
8784 /* We need to use a construction vtable if this is not the primary
8785 VTT. */
8787 {
8790 /* Record the offset in the VTT where this sub-VTT can be found. */
8792 }
8794 /* Add the address of the primary vtable for the complete object. */
8798 {
8801 }
8804 /* Recursively add the secondary VTTs for non-virtual bases. */
8809 /* Add secondary virtual pointers for all subobjects of BINFO with
8810 either virtual bases or reachable along a virtual path, except
8811 subobjects that are non-virtual primary bases. */
8821 /* data.inits might have grown as we added secondary virtual pointers.
8822 Make sure our caller knows about the new vector. */
8826 /* Add the secondary VTTs for virtual bases in inheritance graph
8827 order. */
8829 {
8834 }
8835 else
8836 /* Remove the ctor vtables we created. */
8838 }
8840 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8841 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8843 static tree
8845 {
8848 /* We don't care about bases that don't have vtables. */
8852 /* We're only interested in proper subobjects of the type being
8853 constructed. */
8857 /* We're only interested in bases with virtual bases or reachable
8858 via a virtual path from the type being constructed. */
8863 /* We're not interested in non-virtual primary bases. */
8867 /* Record the index where this secondary vptr can be found. */
8869 {
8874 {
8875 /* It's a primary virtual base, and this is not a
8876 construction vtable. Find the base this is primary of in
8877 the inheritance graph, and use that base's vtable
8878 now. */
8881 }
8882 }
8884 /* Add the initializer for the secondary vptr itself. */
8887 /* Advance the vtt index. */
8892 }
8894 /* Called from build_vtt_inits via dfs_walk. After building
8895 constructor vtables and generating the sub-vtt from them, we need
8896 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8897 binfo of the base whose sub vtt was generated. */
8899 static tree
8901 {
8905 /* If this class has no vtable, none of its bases do. */
8909 /* This might be a primary base, so have no vtable in this
8910 hierarchy. */
8913 /* If we scribbled the construction vtable vptr into BINFO, clear it
8914 out now. */
8920 }
8922 /* Build the construction vtable group for BINFO which is in the
8923 hierarchy dominated by T. */
8925 static void
8927 {
8928 tree type;
8929 tree vtbl;
8930 tree id;
8931 tree vbase;
8934 /* See if we've already created this construction vtable group. */
8940 /* Build a version of VTBL (with the wrong type) for use in
8941 constructing the addresses of secondary vtables in the
8942 construction vtable group. */
8945 /* Don't export construction vtables from shared libraries. Even on
8946 targets that don't support hidden visibility, this tells
8947 can_refer_decl_in_current_unit_p not to assume that it's safe to
8948 access from a different compilation unit (bz 54314). */
8956 /* Add the vtables for each of our virtual bases using the vbase in T
8957 binfo. */
8959 vbase;
8961 {
8962 tree b;
8969 }
8971 /* Figure out the type of the construction vtable. */
8978 /* Initialize the construction vtable. */
8982 }
8984 /* Add the vtbl initializers for BINFO (and its bases other than
8985 non-virtual primaries) to the list of INITS. BINFO is in the
8986 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
8987 the constructor the vtbl inits should be accumulated for. (If this
8988 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
8989 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
8990 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
8991 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
8992 but are not necessarily the same in terms of layout. */
8994 static void
8996 tree orig_binfo,
8997 tree rtti_binfo,
8998 tree vtbl,
8999 tree t,
9001 {
9003 tree base_binfo;
9008 /* If it doesn't have a vptr, we don't do anything. */
9012 /* If we're building a construction vtable, we're not interested in
9013 subobjects that don't require construction vtables. */
9019 /* Build the initializers for the BINFO-in-T vtable. */
9022 /* Walk the BINFO and its bases. We walk in preorder so that as we
9023 initialize each vtable we can figure out at what offset the
9024 secondary vtable lies from the primary vtable. We can't use
9025 dfs_walk here because we need to iterate through bases of BINFO
9026 and RTTI_BINFO simultaneously. */
9028 {
9029 /* Skip virtual bases. */
9035 inits);
9036 }
9037 }
9039 /* Called from accumulate_vtbl_inits. Adds the initializers for the
9040 BINFO vtable to L. */
9042 static void
9044 tree orig_binfo,
9045 tree rtti_binfo,
9046 tree orig_vtbl,
9047 tree t,
9049 {
9056 {
9057 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9058 primary virtual base. If it is not the same primary in
9059 the hierarchy of T, we'll need to generate a ctor vtable
9060 for it, to place at its location in T. If it is the same
9061 primary, we still need a VTT entry for the vtable, but it
9062 should point to the ctor vtable for the base it is a
9063 primary for within the sub-hierarchy of RTTI_BINFO.
9065 There are three possible cases:
9067 1) We are in the same place.
9068 2) We are a primary base within a lost primary virtual base of
9069 RTTI_BINFO.
9070 3) We are primary to something not a base of RTTI_BINFO. */
9072 tree b;
9075 /* First, look through the bases we are primary to for RTTI_BINFO
9076 or a virtual base. */
9079 {
9084 }
9085 /* If we run out of primary links, keep looking down our
9086 inheritance chain; we might be an indirect primary. */
9090 found:
9092 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9093 base B and it is a base of RTTI_BINFO, this is case 2. In
9094 either case, we share our vtable with LAST, i.e. the
9095 derived-most base within B of which we are a primary. */
9098 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9099 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9100 binfo_ctor_vtable after everything's been set up. */
9103 /* Otherwise, this is case 3 and we get our own. */
9104 }
9111 {
9112 tree index;
9115 /* Add the initializer for this vtable. */
9119 /* Figure out the position to which the VPTR should point. */
9125 }
9128 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9129 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9130 straighten this out. */
9133 /* Throw away any unneeded intializers. */
9135 else
9136 /* For an ordinary vtable, set BINFO_VTABLE. */
9138 }
9143 /* Construct the initializer for BINFO's virtual function table. BINFO
9144 is part of the hierarchy dominated by T. If we're building a
9145 construction vtable, the ORIG_BINFO is the binfo we should use to
9146 find the actual function pointers to put in the vtable - but they
9147 can be overridden on the path to most-derived in the graph that
9148 ORIG_BINFO belongs. Otherwise,
9149 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9150 BINFO that should be indicated by the RTTI information in the
9151 vtable; it will be a base class of T, rather than T itself, if we
9152 are building a construction vtable.
9154 The value returned is a TREE_LIST suitable for wrapping in a
9155 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9156 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9157 number of non-function entries in the vtable.
9159 It might seem that this function should never be called with a
9160 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9161 base is always subsumed by a derived class vtable. However, when
9162 we are building construction vtables, we do build vtables for
9163 primary bases; we need these while the primary base is being
9164 constructed. */
9166 static void
9168 tree orig_binfo,
9169 tree t,
9170 tree rtti_binfo,
9173 {
9174 tree v;
9175 vtbl_init_data vid;
9177 tree vbinfo;
9181 /* Initialize VID. */
9189 /* The first vbase or vcall offset is at index -3 in the vtable. */
9192 /* Add entries to the vtable for RTTI. */
9195 /* Create an array for keeping track of the functions we've
9196 processed. When we see multiple functions with the same
9197 signature, we share the vcall offsets. */
9199 /* Add the vcall and vbase offset entries. */
9202 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9203 build_vbase_offset_vtbl_entries. */
9208 /* If the target requires padding between data entries, add that now. */
9210 {
9215 /* Move data entries into their new positions and add padding
9216 after the new positions. Iterate backwards so we don't
9217 overwrite entries that we would need to process later. */
9220 ix--)
9221 {
9229 {
9233 null_pointer_node);
9234 }
9235 }
9236 }
9241 /* The initializers for virtual functions were built up in reverse
9242 order. Straighten them out and add them to the running list in one
9243 step. */
9252 /* Go through all the ordinary virtual functions, building up
9253 initializers. */
9255 {
9256 tree delta;
9257 tree vcall_index;
9264 {
9268 {
9271 }
9273 }
9275 /* If the only definition of this function signature along our
9276 primary base chain is from a lost primary, this vtable slot will
9277 never be used, so just zero it out. This is important to avoid
9278 requiring extra thunks which cannot be generated with the function.
9280 We first check this in update_vtable_entry_for_fn, so we handle
9281 restored primary bases properly; we also need to do it here so we
9282 zero out unused slots in ctor vtables, rather than filling them
9283 with erroneous values (though harmless, apart from relocation
9284 costs). */
9289 {
9290 /* Pull the offset for `this', and the function to call, out of
9291 the list. */
9298 /* You can't call an abstract virtual function; it's abstract.
9299 So, we replace these functions with __pure_virtual. */
9301 {
9304 {
9306 abort_fndecl_addr
9310 }
9311 }
9312 /* Likewise for deleted virtuals. */
9314 {
9316 {
9320 dvirt_fn = push_library_fn
9324 }
9329 }
9330 else
9331 {
9333 {
9338 }
9339 /* Take the address of the function, considering it to be of an
9340 appropriate generic type. */
9344 /* Don't refer to a virtual destructor from a constructor
9345 vtable or a vtable for an abstract class, since destroying
9346 an object under construction is undefined behavior and we
9347 don't want it to be considered a candidate for speculative
9348 devirtualization. But do create the thunk for ABI
9349 compliance. */
9354 }
9355 }
9357 /* And add it to the chain of initializers. */
9359 {
9364 else
9366 {
9372 }
9373 }
9374 else
9376 }
9377 }
9379 /* Adds to vid->inits the initializers for the vbase and vcall
9380 offsets in BINFO, which is in the hierarchy dominated by T. */
9382 static void
9384 {
9385 tree b;
9387 /* If this is a derived class, we must first create entries
9388 corresponding to the primary base class. */
9393 /* Add the vbase entries for this base. */
9395 /* Add the vcall entries for this base. */
9397 }
9399 /* Returns the initializers for the vbase offset entries in the vtable
9400 for BINFO (which is part of the class hierarchy dominated by T), in
9401 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9402 where the next vbase offset will go. */
9404 static void
9406 {
9407 tree vbase;
9408 tree t;
9409 tree non_primary_binfo;
9411 /* If there are no virtual baseclasses, then there is nothing to
9412 do. */
9418 /* We might be a primary base class. Go up the inheritance hierarchy
9419 until we find the most derived class of which we are a primary base:
9420 it is the offset of that which we need to use. */
9423 {
9424 tree b;
9426 /* If we have reached a virtual base, then it must be a primary
9427 base (possibly multi-level) of vid->binfo, or we wouldn't
9428 have called build_vcall_and_vbase_vtbl_entries for it. But it
9429 might be a lost primary, so just skip down to vid->binfo. */
9431 {
9434 }
9440 }
9442 /* Go through the virtual bases, adding the offsets. */
9444 vbase;
9446 {
9447 tree b;
9448 tree delta;
9453 /* Find the instance of this virtual base in the complete
9454 object. */
9457 /* If we've already got an offset for this virtual base, we
9458 don't need another one. */
9463 /* Figure out where we can find this vbase offset. */
9472 /* The vbase offset had better be the same. */
9475 /* The next vbase will come at a more negative offset. */
9479 /* The initializer is the delta from BINFO to this virtual base.
9480 The vbase offsets go in reverse inheritance-graph order, and
9481 we are walking in inheritance graph order so these end up in
9482 the right order. */
9489 }
9490 }
9492 /* Adds the initializers for the vcall offset entries in the vtable
9493 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9494 to VID->INITS. */
9496 static void
9498 {
9499 /* We only need these entries if this base is a virtual base. We
9500 compute the indices -- but do not add to the vtable -- when
9501 building the main vtable for a class. */
9504 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9505 correspond to VID->DERIVED), we are building a primary
9506 construction virtual table. Since this is a primary
9507 virtual table, we do not need the vcall offsets for
9508 BINFO. */
9510 {
9511 /* We need a vcall offset for each of the virtual functions in this
9512 vtable. For example:
9514 class A { virtual void f (); };
9515 class B1 : virtual public A { virtual void f (); };
9516 class B2 : virtual public A { virtual void f (); };
9517 class C: public B1, public B2 { virtual void f (); };
9519 A C object has a primary base of B1, which has a primary base of A. A
9520 C also has a secondary base of B2, which no longer has a primary base
9521 of A. So the B2-in-C construction vtable needs a secondary vtable for
9522 A, which will adjust the A* to a B2* to call f. We have no way of
9523 knowing what (or even whether) this offset will be when we define B2,
9524 so we store this "vcall offset" in the A sub-vtable and look it up in
9525 a "virtual thunk" for B2::f.
9527 We need entries for all the functions in our primary vtable and
9528 in our non-virtual bases' secondary vtables. */
9530 /* If we are just computing the vcall indices -- but do not need
9531 the actual entries -- not that. */
9534 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9536 }
9537 }
9539 /* Build vcall offsets, starting with those for BINFO. */
9541 static void
9543 {
9545 tree primary_binfo;
9546 tree base_binfo;
9548 /* Don't walk into virtual bases -- except, of course, for the
9549 virtual base for which we are building vcall offsets. Any
9550 primary virtual base will have already had its offsets generated
9551 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9555 /* If BINFO has a primary base, process it first. */
9560 /* Add BINFO itself to the list. */
9563 /* Scan the non-primary bases of BINFO. */
9567 }
9569 /* Called from build_vcall_offset_vtbl_entries_r. */
9571 static void
9573 {
9574 /* Make entries for the rest of the virtuals. */
9575 tree orig_fn;
9577 /* The ABI requires that the methods be processed in declaration
9578 order. */
9580 orig_fn;
9584 }
9586 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9588 static void
9590 {
9592 tree vcall_offset;
9593 tree derived_entry;
9595 /* If there is already an entry for a function with the same
9596 signature as FN, then we do not need a second vcall offset.
9597 Check the list of functions already present in the derived
9598 class vtable. */
9600 {
9602 /* We only use one vcall offset for virtual destructors,
9603 even though there are two virtual table entries. */
9607 }
9609 /* If we are building these vcall offsets as part of building
9610 the vtable for the most derived class, remember the vcall
9611 offset. */
9613 {
9616 }
9618 /* The next vcall offset will be found at a more negative
9619 offset. */
9623 /* Keep track of this function. */
9627 {
9628 tree base;
9629 tree fn;
9631 /* Find the overriding function. */
9635 else
9636 {
9639 /* The vbase we're working on is a primary base of
9640 vid->binfo. But it might be a lost primary, so its
9641 BINFO_OFFSET might be wrong, so we just use the
9642 BINFO_OFFSET from vid->binfo. */
9648 vcall_offset);
9649 }
9650 /* Add the initializer to the vtable. */
9652 }
9653 }
9655 /* Return vtbl initializers for the RTTI entries corresponding to the
9656 BINFO's vtable. The RTTI entries should indicate the object given
9657 by VID->rtti_binfo. */
9659 static void
9661 {
9662 tree b;
9663 tree t;
9664 tree offset;
9665 tree decl;
9666 tree init;
9670 /* To find the complete object, we will first convert to our most
9671 primary base, and then add the offset in the vtbl to that value. */
9676 /* The second entry is the address of the typeinfo object. */
9679 else
9682 /* Convert the declaration to a type that can be stored in the
9683 vtable. */
9687 /* Add the offset-to-top entry. It comes earlier in the vtable than
9688 the typeinfo entry. Convert the offset to look like a
9689 function pointer, so that we can put it in the vtable. */
9692 }
9694 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9695 accessibility. */
9697 bool
9699 {
9702 }
9704 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9706 bool
9708 {
9712 }
9714 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9715 class between them, if any. */
9717 tree
9719 {
9731 {
9734 }
9738 }