| blob | 73529a94a52377c74c1c06229aeff738f2aa4883 |
1 /* Functions related to building classes and their related objects.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
22 /* High-level class interface. */
41 /* Id for dumping the class hierarchy. */
44 /* The number of nested classes being processed. If we are not in the
45 scope of any class, this is zero. */
49 /* In order to deal with nested classes, we keep a stack of classes.
50 The topmost entry is the innermost class, and is the entry at index
51 CURRENT_CLASS_DEPTH */
54 /* The name of the class. */
55 tree name;
57 /* The _TYPE node for the class. */
58 tree type;
60 /* The access specifier pending for new declarations in the scope of
61 this class. */
62 tree access;
64 /* If were defining TYPE, the names used in this class. */
65 splay_tree names_used;
67 /* Nonzero if this class is no longer open, because of a call to
68 push_to_top_level. */
72 struct vtbl_init_data
73 {
74 /* The base for which we're building initializers. */
75 tree binfo;
76 /* The type of the most-derived type. */
77 tree derived;
78 /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
79 unless ctor_vtbl_p is true. */
80 tree rtti_binfo;
81 /* The negative-index vtable initializers built up so far. These
82 are in order from least negative index to most negative index. */
84 /* The binfo for the virtual base for which we're building
85 vcall offset initializers. */
86 tree vbase;
87 /* The functions in vbase for which we have already provided vcall
88 offsets. */
90 /* The vtable index of the next vcall or vbase offset. */
91 tree index;
92 /* Nonzero if we are building the initializer for the primary
93 vtable. */
95 /* Nonzero if we are building the initializer for a construction
96 vtable. */
98 /* True when adding vcall offset entries to the vtable. False when
99 merely computing the indices. */
101 };
103 /* The type of a function passed to walk_subobject_offsets. */
106 /* The stack itself. This is a dynamically resized array. The
107 number of elements allocated is CURRENT_CLASS_STACK_SIZE. */
111 /* The size of the largest empty class seen in this translation unit. */
114 /* An array of all local classes present in this translation unit, in
115 declaration order. */
148 /* Used by find_flexarrays and related functions. */
199 tree *);
209 splay_tree_key k2);
218 /* Variables shared between class.c and call.c. */
228 /* Return a COND_EXPR that executes TRUE_STMT if this execution of the
229 'structor is in charge of 'structing virtual bases, or FALSE_STMT
230 otherwise. */
232 tree
234 {
244 }
246 /* Convert to or from a base subobject. EXPR is an expression of type
247 `A' or `A*', an expression of type `B' or `B*' is returned. To
248 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
249 the B base instance within A. To convert base A to derived B, CODE
250 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
251 In this latter case, A must not be a morally virtual base of B.
252 NONNULL is true if EXPR is known to be non-NULL (this is only
253 needed when EXPR is of pointer type). CV qualifiers are preserved
254 from EXPR. */
256 tree
258 tree expr,
259 tree binfo,
261 tsubst_flags_t complain)
262 {
265 tree probe;
266 tree offset;
267 tree target_type;
269 tree ptr_target_type;
280 {
286 }
294 {
295 /* This can happen when adjust_result_of_qualified_name_lookup can't
296 find a unique base binfo in a call to a member function. We
297 couldn't give the diagnostic then since we might have been calling
298 a static member function, so we do it now. In other cases, eg.
299 during error recovery (c++/71979), we may not have a base at all. */
301 {
305 }
307 }
314 /* Nothing to do. */
318 {
320 {
322 {
325 "pointer to derived class %qT because the base is "
327 else
331 }
332 else
333 {
339 else
343 }
344 }
346 }
349 {
351 /* This must happen before the call to save_expr. */
353 }
354 else
360 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
361 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
362 expression returned matches the input. */
363 target_type = cp_build_qualified_type
367 /* Do we need to look in the vtable for the real offset? */
370 /* Don't bother with the calculations inside sizeof; they'll ICE if the
371 source type is incomplete and the pointer value doesn't matter. In a
372 template (even in instantiate_non_dependent_expr), we don't have vtables
373 set up properly yet, and the value doesn't matter there either; we're
374 just interested in the result of overload resolution. */
376 || processing_template_decl
378 {
381 }
383 /* If we're in an NSDMI, we don't have the full constructor context yet
384 that we need for converting to a virtual base, so just build a stub
385 CONVERT_EXPR and expand it later in bot_replace. */
388 {
392 }
394 /* Do we need to check for a null pointer? */
396 {
397 /* If we know the conversion will not actually change the value
398 of EXPR, then we can avoid testing the expression for NULL.
399 We have to avoid generating a COMPONENT_REF for a base class
400 field, because other parts of the compiler know that such
401 expressions are always non-NULL. */
405 }
407 /* Protect against multiple evaluation if necessary. */
411 /* Now that we've saved expr, build the real null test. */
413 {
417 /* This is a compiler generated comparison, don't emit
418 e.g. -Wnonnull-compare warning for it. */
420 }
422 /* If this is a simple base reference, express it as a COMPONENT_REF. */
424 /* We don't build base fields for empty bases, and they aren't very
425 interesting to the optimizers anyway. */
427 {
436 }
439 {
440 /* Going via virtual base V_BINFO. We need the static offset
441 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
442 V_BINFO. That offset is an entry in D_BINFO's vtable. */
443 tree v_offset;
446 {
447 /* In a base member initializer, we cannot rely on the
448 vtable being set up. We have to indirect via the
449 vtt_parm. */
450 tree t;
456 }
457 else
458 {
462 {
467 }
470 }
478 v_offset);
490 /* Negative fixed_type_p means this is a constructor or destructor;
491 virtual base layout is fixed in in-charge [cd]tors, but not in
492 base [cd]tors. */
493 offset = build_if_in_charge
495 v_offset);
496 else
498 }
506 {
511 }
512 else
515 indout:
517 {
521 }
523 out:
529 }
531 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
532 Perform a derived-to-base conversion by recursively building up a
533 sequence of COMPONENT_REFs to the appropriate base fields. */
535 static tree
537 {
540 tree field;
543 {
544 tree temp;
548 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
549 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
550 an lvalue in the front end; only _DECLs and _REFs are lvalues
551 in the back end. */
557 }
559 /* Recurse. */
564 /* Is this the base field created by build_base_field? */
568 /* If we're looking for a field in the most-derived class,
569 also check the field offset; we can have two base fields
570 of the same type if one is an indirect virtual base and one
571 is a direct non-virtual base. */
575 {
576 /* We don't use build_class_member_access_expr here, as that
577 has unnecessary checks, and more importantly results in
578 recursive calls to dfs_walk_once. */
584 /* Mark the expression const or volatile, as appropriate.
585 Even though we've dealt with the type above, we still have
586 to mark the expression itself. */
593 }
595 /* Didn't find the base field?!? */
597 }
599 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
600 type is a class type or a pointer to a class type. In the former
601 case, TYPE is also a class type; in the latter it is another
602 pointer type. If CHECK_ACCESS is true, an error message is emitted
603 if TYPE is inaccessible. If OBJECT has pointer type, the value is
604 assumed to be non-NULL. */
606 tree
608 tsubst_flags_t complain)
609 {
610 tree binfo;
611 tree object_type;
614 {
617 }
618 else
627 }
629 /* EXPR is an expression with unqualified class type. BASE is a base
630 binfo of that class type. Returns EXPR, converted to the BASE
631 type. This function assumes that EXPR is the most derived class;
632 therefore virtual bases can be found at their static offsets. */
634 tree
636 {
637 tree expr_type;
641 {
642 /* If this is a non-empty base, use a COMPONENT_REF. */
646 /* We use fold_build2 and fold_convert below to simplify the trees
647 provided to the optimizers. It is not safe to call these functions
648 when processing a template because they do not handle C++-specific
649 trees. */
657 }
660 }
662 \f
663 tree
665 {
669 /* Can happen in case of duplicate base types (c++/59082). */
673 /* First, convert to the requested type. */
678 /* Second, the requested type may not be the owner of its own vptr.
679 If not, convert to the base class that owns it. We cannot use
680 convert_to_base here, because VCONTEXT may appear more than once
681 in the inheritance hierarchy of TYPE, and thus direct conversion
682 between the types may be ambiguous. Following the path back up
683 one step at a time via primary bases avoids the problem. */
687 {
690 }
693 }
695 /* Given an object INSTANCE, return an expression which yields the
696 vtable element corresponding to INDEX. There are many special
697 cases for INSTANCE which we take care of here, mainly to avoid
698 creating extra tree nodes when we don't have to. */
700 static tree
702 {
703 tree aref;
706 /* Try to figure out what a reference refers to, and
707 access its virtual function table directly. */
715 {
720 }
729 }
731 tree
733 {
737 }
739 /* Given a stable object pointer INSTANCE_PTR, return an expression which
740 yields a function pointer corresponding to vtable element INDEX. */
742 tree
744 {
745 tree aref;
748 idx);
750 /* When using function descriptors, the address of the
751 vtable entry is treated as a function pointer. */
756 /* Remember this as a method reference, for later devirtualization. */
760 }
762 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
763 for the given TYPE. */
765 static tree
767 {
769 }
771 /* DECL is an entity associated with TYPE, like a virtual table or an
772 implicitly generated constructor. Determine whether or not DECL
773 should have external or internal linkage at the object file
774 level. This routine does not deal with COMDAT linkage and other
775 similar complexities; it simply sets TREE_PUBLIC if it possible for
776 entities in other translation units to contain copies of DECL, in
777 the abstract. */
779 void
781 {
784 }
786 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
787 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
788 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
790 static tree
792 {
793 tree decl;
796 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
797 now to avoid confusion in mangle_decl. */
808 /* The vtable has not been defined -- yet. */
812 /* Mark the VAR_DECL node representing the vtable itself as a
813 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
814 is rather important that such things be ignored because any
815 effort to actually generate DWARF for them will run into
816 trouble when/if we encounter code like:
818 #pragma interface
819 struct S { virtual void member (); };
821 because the artificial declaration of the vtable itself (as
822 manufactured by the g++ front end) will say that the vtable is
823 a static member of `S' but only *after* the debug output for
824 the definition of `S' has already been output. This causes
825 grief because the DWARF entry for the definition of the vtable
826 will try to refer back to an earlier *declaration* of the
827 vtable as a static member of `S' and there won't be one. We
828 might be able to arrange to have the "vtable static member"
829 attached to the member list for `S' before the debug info for
830 `S' get written (which would solve the problem) but that would
831 require more intrusive changes to the g++ front end. */
835 }
837 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
838 or even complete. If this does not exist, create it. If COMPLETE is
839 nonzero, then complete the definition of it -- that will render it
840 impossible to actually build the vtable, but is useful to get at those
841 which are known to exist in the runtime. */
843 tree
845 {
846 tree decl;
855 {
858 }
861 }
863 /* Build the primary virtual function table for TYPE. If BINFO is
864 non-NULL, build the vtable starting with the initial approximation
865 that it is the same as the one which is the head of the association
866 list. Returns a nonzero value if a new vtable is actually
867 created. */
869 static int
871 {
872 tree decl;
873 tree virtuals;
878 {
880 /* We have already created a vtable for this base, so there's
881 no need to do it again. */
888 }
889 else
890 {
893 }
896 {
899 }
901 /* Initialize the association list for this type, based
902 on our first approximation. */
907 }
909 /* Give BINFO a new virtual function table which is initialized
910 with a skeleton-copy of its original initialization. The only
911 entry that changes is the `delta' entry, so we can really
912 share a lot of structure.
914 FOR_TYPE is the most derived type which caused this table to
915 be needed.
917 Returns nonzero if we haven't met BINFO before.
919 The order in which vtables are built (by calling this function) for
920 an object must remain the same, otherwise a binary incompatibility
921 can result. */
923 static int
925 {
927 /* We already created a vtable for this base. There's no need to
928 do it again. */
931 /* Remember that we've created a vtable for this BINFO, so that we
932 don't try to do so again. */
935 /* Make fresh virtual list, so we can smash it later. */
938 /* Secondary vtables are laid out as part of the same structure as
939 the primary vtable. */
942 }
944 /* Create a new vtable for BINFO which is the hierarchy dominated by
945 T. Return nonzero if we actually created a new vtable. */
947 static int
949 {
951 /* In this case, it is *type*'s vtable we are modifying. We start
952 with the approximation that its vtable is that of the
953 immediate base class. */
955 else
956 /* This is our very own copy of `basetype' to play with. Later,
957 we will fill in all the virtual functions that override the
958 virtual functions in these base classes which are not defined
959 by the current type. */
961 }
963 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
964 (which is in the hierarchy dominated by T) list FNDECL as its
965 BV_FN. DELTA is the required constant adjustment from the `this'
966 pointer where the vtable entry appears to the `this' required when
967 the function is actually called. */
969 static void
971 tree binfo,
972 tree fndecl,
973 tree delta,
975 {
976 tree v;
982 {
983 /* We need a new vtable for BINFO. */
985 {
986 /* If we really did make a new vtable, we also made a copy
987 of the BINFO_VIRTUALS list. Now, we have to find the
988 corresponding entry in that list. */
993 }
998 }
999 }
1001 \f
1002 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
1003 METHOD is being injected via a using_decl. Returns true if the
1004 method could be added to the method vec. */
1006 bool
1008 {
1012 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1020 /* Check to see if we've already got this method. */
1022 {
1024 tree fn_type;
1025 tree method_type;
1026 tree parms1;
1027 tree parms2;
1032 /* Two using-declarations can coexist, we'll complain about ambiguity in
1033 overload resolution. */
1035 /* Except handle inherited constructors specially. */
1039 /* [over.load] Member function declarations with the
1040 same name and the same parameter types cannot be
1041 overloaded if any of them is a static member
1042 function declaration.
1044 [over.load] Member function declarations with the same name and
1045 the same parameter-type-list as well as member function template
1046 declarations with the same name, the same parameter-type-list, and
1047 the same template parameter lists cannot be overloaded if any of
1048 them, but not all, have a ref-qualifier.
1050 [namespace.udecl] When a using-declaration brings names
1051 from a base class into a derived class scope, member
1052 functions in the derived class override and/or hide member
1053 functions with the same name and parameter types in a base
1054 class (rather than conflicting). */
1060 /* Compare the quals on the 'this' parm. Don't compare
1061 the whole types, as used functions are treated as
1062 coming from the using class in overload resolution. */
1065 /* Either both or neither need to be ref-qualified for
1066 differing quals to allow overloading. */
1073 /* For templates, the return type and template parameters
1074 must be identical. */
1087 /* Bring back parameters omitted from an inherited ctor. */
1098 {
1099 /* If these are versions of the same function, process and
1100 move on. */
1106 {
1108 {
1112 {
1114 {
1115 /* Inheriting the same constructor along different
1116 paths, combine them. */
1117 SET_DECL_INHERITED_CTOR
1120 /* And discard the new one. */
1122 }
1123 else
1124 /* Inherited ctors can coexist until overload
1125 resolution. */
1127 }
1133 basef);
1134 }
1135 /* Otherwise defer to the other function. */
1137 }
1140 /* Defer to the local function. */
1144 {
1145 /* Remove the inherited constructor. */
1148 }
1149 else
1150 {
1156 }
1157 }
1158 }
1160 /* A class should never have more than one destructor. */
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
1525 }
1530 }
1532 /* Check that DECL has all the ABI tags that are used in parts of its type
1533 that are not reflected in its mangled name. */
1535 void
1537 {
1544 }
1546 /* Return any ABI tags that are used in parts of the type of DECL
1547 that are not reflected in its mangled name. This function is only
1548 used in backward-compatible mangling for ABI <11. */
1550 tree
1552 {
1556 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1557 that we can use this function for setting need_abi_warning
1558 regardless of the current flag_abi_version. */
1561 else
1563 }
1565 void
1567 {
1577 {
1580 {
1584 }
1585 }
1587 // If we found some tags on our template arguments, add them to our
1588 // abi_tag attribute.
1590 {
1594 else
1598 }
1601 }
1603 /* Return true, iff class T has a non-virtual destructor that is
1604 accessible from outside the class heirarchy (i.e. is public, or
1605 there's a suitable friend. */
1607 static bool
1609 {
1612 /* An implicitly declared destructor is always public. And,
1613 if it were virtual, we would have created it by now. */
1628 }
1630 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1631 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1632 properties of the bases. */
1634 static void
1638 {
1642 tree base_binfo;
1643 tree binfo;
1653 {
1662 /* If any base class is non-literal, so is the derived class. */
1666 /* If the base class doesn't have copy constructors or
1667 assignment operators that take const references, then the
1668 derived class cannot have such a member automatically
1669 generated. */
1678 /* A virtual base does not effect nearly emptiness. */
1679 ;
1681 {
1683 /* And if there is more than one nearly empty base, then the
1684 derived class is not nearly empty either. */
1686 else
1687 /* Remember we've seen one. */
1689 }
1691 /* If the base class is not empty or nearly empty, then this
1692 class cannot be nearly empty. */
1695 /* A lot of properties from the bases also apply to the derived
1696 class. */
1713 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1716 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1722 /* A standard-layout class is a class that:
1723 ...
1724 * has no non-standard-layout base classes, */
1727 {
1728 tree basefield;
1729 /* ...has no base classes of the same type as the first non-static
1730 data member... */
1732 && (same_type_ignoring_top_level_qualifiers_p
1735 else
1736 /* ...either has no non-static data members in the most-derived
1737 class and at most one base class with non-static data
1738 members, or has no base classes with non-static data
1739 members */
1745 {
1748 else
1751 }
1752 }
1754 /* Don't bother collecting tm attributes if transactional memory
1755 support is not enabled. */
1757 {
1761 }
1764 }
1766 /* If one of the base classes had TM attributes, and the current class
1767 doesn't define its own, then the current class inherits one. */
1769 {
1772 }
1773 }
1775 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1776 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1777 that have had a nearly-empty virtual primary base stolen by some
1778 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1779 T. */
1781 static void
1783 {
1787 tree base_binfo;
1789 /* Determine the primary bases of our bases. */
1792 {
1795 /* See if we're the non-virtual primary of our inheritance
1796 chain. */
1798 {
1805 /* We are the primary binfo. */
1807 }
1808 /* Determine if we have a virtual primary base, and mark it so.
1809 */
1811 {
1815 /* Someone already claimed this base. */
1817 else
1818 {
1819 tree delta;
1824 /* A virtual binfo might have been copied from within
1825 another hierarchy. As we're about to use it as a
1826 primary base, make sure the offsets match. */
1834 }
1835 }
1836 }
1838 /* First look for a dynamic direct non-virtual base. */
1840 {
1844 {
1847 }
1848 }
1850 /* A "nearly-empty" virtual base class can be the primary base
1851 class, if no non-virtual polymorphic base can be found. Look for
1852 a nearly-empty virtual dynamic base that is not already a primary
1853 base of something in the hierarchy. If there is no such base,
1854 just pick the first nearly-empty virtual base. */
1860 {
1862 {
1863 /* Found one that is not primary. */
1866 }
1868 /* Remember the first candidate. */
1870 }
1872 found:
1873 /* If we've got a primary base, use it. */
1875 {
1880 /* We are stealing a primary base. */
1884 {
1885 tree delta;
1888 /* A virtual binfo might have been copied from within
1889 another hierarchy. As we're about to use it as a primary
1890 base, make sure the offsets match. */
1895 }
1902 }
1903 }
1905 /* Update the variant types of T. */
1907 void
1909 {
1910 tree variants;
1916 variants;
1918 {
1919 /* These fields are in the _TYPE part of the node, not in
1920 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1930 /* Copy whatever these are holding today. */
1933 }
1934 }
1936 /* KLASS is a class that we're applying may_alias to after the body is
1937 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
1938 canonical type(s) will be implicitly updated. */
1940 static void
1942 {
1951 }
1953 /* Early variant fixups: we apply attributes at the beginning of the class
1954 definition, and we need to fix up any variants that have already been
1955 made via elaborated-type-specifier so that check_qualified_type works. */
1957 void
1959 {
1960 tree variants;
1974 variants;
1976 {
1977 /* These are the two fields that check_qualified_type looks at and
1978 are affected by attributes. */
1983 else
1988 }
1989 }
1990 \f
1991 /* Set memoizing fields and bits of T (and its variants) for later
1992 use. */
1994 static void
1996 {
1997 /* Fix up variants (if any). */
2001 /* For a class w/o baseclasses, 'finish_struct' has set
2002 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2003 Similarly for a class whose base classes do not have vtables.
2004 When neither of these is true, we might have removed abstract
2005 virtuals (by providing a definition), added some (by declaring
2006 new ones), or redeclared ones from a base class. We need to
2007 recalculate what's really an abstract virtual at this point (by
2008 looking in the vtables). */
2011 /* If this type has a copy constructor or a destructor, force its
2012 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2013 nonzero. This will cause it to be passed by invisible reference
2014 and prevent it from being returned in a register. */
2017 {
2018 tree variants;
2021 {
2024 }
2025 }
2026 }
2028 /* Issue warnings about T having private constructors, but no friends,
2029 and so forth.
2031 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2032 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2033 non-private static member functions. */
2035 static void
2037 {
2042 /* If the class has friends, those entities might create and
2043 access instances, so we should not warn. */
2046 /* We will have warned when the template was declared; there's
2047 no need to warn on every instantiation. */
2049 /* There's no reason to even consider warning about this
2050 class. */
2053 /* We only issue one warning, if more than one applies, because
2054 otherwise, on code like:
2056 class A {
2057 // Oops - forgot `public:'
2058 A();
2059 A(const A&);
2060 ~A();
2061 };
2063 we warn several times about essentially the same problem. */
2065 /* Check to see if all (non-constructor, non-destructor) member
2066 functions are private. (Since there are no friends or
2067 non-private statics, we can't ever call any of the private member
2068 functions.) */
2073 /* We're not interested in compiler-generated methods; they don't
2076 {
2078 /* A non-private static member function is just like a
2079 friend; it can create and invoke private member
2080 functions, and be accessed without a class
2081 instance. */
2085 /* Keep searching for a static member function. */
2086 }
2091 {
2092 /* There are no non-private methods, and there's at least one
2093 private member function that isn't a constructor or
2094 destructor. (If all the private members are
2095 constructors/destructors we want to use the code below that
2096 issues error messages specifically referring to
2097 constructors/destructors.) */
2103 {
2106 }
2108 {
2112 }
2113 }
2115 /* Even if some of the member functions are non-private, the class
2116 won't be useful for much if all the constructors or destructors
2117 are private: such an object can never be created or destroyed. */
2120 {
2123 t);
2125 }
2127 /* Warn about classes that have private constructors and no friends. */
2129 /* Implicitly generated constructors are always public. */
2131 {
2135 /* If a non-template class does not define a copy
2136 constructor, one is defined for it, enabling it to avoid
2137 this warning. For a template class, this does not
2138 happen, and so we would normally get a warning on:
2140 template <class T> class C { private: C(); };
2142 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2143 complete non-template or fully instantiated classes have this
2144 flag set. */
2147 else
2153 /* Ideally, we wouldn't count any constructor that takes
2154 an argument of the class type as a parameter, because
2155 such things cannot be used to construct an instance of
2156 the class unless you already have one. */
2158 else
2162 {
2165 t);
2171 }
2172 }
2173 }
2175 /* Make BINFO's vtable have N entries, including RTTI entries,
2176 vbase and vcall offsets, etc. Set its type and call the back end
2177 to lay it out. */
2179 static void
2181 {
2182 tree atype;
2183 tree vtable;
2188 /* We may have to grow the vtable. */
2191 {
2195 }
2196 }
2198 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2199 have the same signature. */
2201 int
2203 {
2204 /* One destructor overrides another if they are the same kind of
2205 destructor. */
2209 /* But a non-destructor never overrides a destructor, nor vice
2210 versa, nor do different kinds of destructors override
2211 one-another. For example, a complete object destructor does not
2212 override a deleting destructor. */
2221 {
2229 }
2231 }
2233 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2234 subobject. */
2236 static bool
2238 {
2239 tree probe;
2242 {
2246 /* If we meet a virtual base, we can't follow the inheritance
2247 any more. See if the complete type of DERIVED contains
2248 such a virtual base. */
2251 }
2253 }
2256 /* The function for which we are trying to find a final overrider. */
2257 tree fn;
2258 /* The base class in which the function was declared. */
2259 tree declaring_base;
2260 /* The candidate overriders. */
2261 tree candidates;
2262 /* Path to most derived. */
2264 };
2266 /* Add the overrider along the current path to FFOD->CANDIDATES.
2267 Returns true if an overrider was found; false otherwise. */
2269 static bool
2273 {
2274 tree method;
2276 /* If BINFO is not the most derived type, try a more derived class.
2277 A definition there will overrider a definition here. */
2279 {
2280 depth--;
2284 }
2288 {
2291 /* Remove any candidates overridden by this new function. */
2293 {
2294 /* If *CANDIDATE overrides METHOD, then METHOD
2295 cannot override anything else on the list. */
2298 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2301 else
2303 }
2305 /* Add the new function. */
2308 }
2311 }
2313 /* Called from find_final_overrider via dfs_walk. */
2315 static tree
2317 {
2325 }
2327 static tree
2329 {
2334 }
2336 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2337 FN and whose TREE_VALUE is the binfo for the base where the
2338 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2339 DERIVED) is the base object in which FN is declared. */
2341 static tree
2343 {
2344 find_final_overrider_data ffod;
2346 /* Getting this right is a little tricky. This is valid:
2348 struct S { virtual void f (); };
2349 struct T { virtual void f (); };
2350 struct U : public S, public T { };
2352 even though calling `f' in `U' is ambiguous. But,
2354 struct R { virtual void f(); };
2355 struct S : virtual public R { virtual void f (); };
2356 struct T : virtual public R { virtual void f (); };
2357 struct U : public S, public T { };
2359 is not -- there's no way to decide whether to put `S::f' or
2360 `T::f' in the vtable for `R'.
2362 The solution is to look at all paths to BINFO. If we find
2363 different overriders along any two, then there is a problem. */
2367 /* Determine the depth of the hierarchy. */
2378 /* If there was no winner, issue an error message. */
2383 }
2385 /* Return the index of the vcall offset for FN when TYPE is used as a
2386 virtual base. */
2388 static tree
2390 {
2392 tree_pair_p p;
2400 /* There should always be an appropriate index. */
2402 }
2404 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2405 dominated by T. FN is the old function; VIRTUALS points to the
2406 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2407 of that entry in the list. */
2409 static void
2412 {
2413 tree b;
2414 tree overrider;
2415 tree delta;
2416 tree virtual_base;
2417 tree first_defn;
2423 /* Find the nearest primary base (possibly binfo itself) which defines
2424 this function; this is the class the caller will convert to when
2425 calling FN through BINFO. */
2427 {
2432 /* The nearest definition is from a lost primary. */
2435 }
2438 /* Find the final overrider. */
2441 {
2444 }
2447 /* Check for adjusting covariant return types. */
2455 /* If the overrider is invalid, don't even try. */
2457 {
2458 /* If FN is a covariant thunk, we must figure out the adjustment
2459 to the final base FN was converting to. As OVERRIDER_TARGET might
2460 also be converting to the return type of FN, we have to
2461 combine the two conversions here. */
2468 {
2472 }
2473 else
2477 /* Find the equivalent binfo within the return type of the
2478 overriding function. We will want the vbase offset from
2479 there. */
2481 over_return);
2484 {
2485 /* There was no existing virtual thunk (which takes
2486 precedence). So find the binfo of the base function's
2487 return type within the overriding function's return type.
2488 Fortunately we know the covariancy is valid (it
2489 has already been checked), so we can just iterate along
2490 the binfos, which have been chained in inheritance graph
2491 order. Of course it is lame that we have to repeat the
2492 search here anyway -- we should really be caching pieces
2493 of the vtable and avoiding this repeated work. */
2496 /* Find the base binfo within the overriding function's
2497 return type. We will always find a thunk_binfo, except
2498 when the covariancy is invalid (which we will have
2499 already diagnosed). */
2502 thunk_binfo;
2508 /* See if virtual inheritance is involved. */
2510 virtual_offset;
2517 {
2521 {
2522 /* We convert via virtual base. Adjust the fixed
2523 offset to be from there. */
2524 offset =
2528 }
2530 /* There was an existing fixed offset, this must be
2531 from the base just converted to, and the base the
2532 FN was thunking to. */
2534 else
2536 }
2537 }
2540 /* Replace the overriding function with a covariant thunk. We
2541 will emit the overriding function in its own slot as
2542 well. */
2545 }
2546 else
2550 /* If we need a covariant thunk, then we may need to adjust first_defn.
2551 The ABI specifies that the thunks emitted with a function are
2552 determined by which bases the function overrides, so we need to be
2553 sure that we're using a thunk for some overridden base; even if we
2554 know that the necessary this adjustment is zero, there may not be an
2555 appropriate zero-this-adjustment thunk for us to use since thunks for
2556 overriding virtual bases always use the vcall offset.
2558 Furthermore, just choosing any base that overrides this function isn't
2559 quite right, as this slot won't be used for calls through a type that
2560 puts a covariant thunk here. Calling the function through such a type
2561 will use a different slot, and that slot is the one that determines
2562 the thunk emitted for that base.
2564 So, keep looking until we find the base that we're really overriding
2565 in this slot: the nearest primary base that doesn't use a covariant
2566 thunk in this slot. */
2568 {
2570 /* We already know that the overrider needs a covariant thunk. */
2573 {
2580 }
2582 }
2584 /* Assume that we will produce a thunk that convert all the way to
2585 the final overrider, and not to an intermediate virtual base. */
2588 /* See if we can convert to an intermediate virtual base first, and then
2589 use the vcall offset located there to finish the conversion. */
2591 {
2592 /* If we find the final overrider, then we can stop
2593 walking. */
2598 /* If we find a virtual base, and we haven't yet found the
2599 overrider, then there is a virtual base between the
2600 declaring base (first_defn) and the final overrider. */
2602 {
2605 }
2606 }
2608 /* Compute the constant adjustment to the `this' pointer. The
2609 `this' pointer, when this function is called, will point at BINFO
2610 (or one of its primary bases, which are at the same offset). */
2612 /* The `this' pointer needs to be adjusted from the declaration to
2613 the nearest virtual base. */
2618 /* If the nearest definition is in a lost primary, we don't need an
2619 entry in our vtable. Except possibly in a constructor vtable,
2620 if we happen to get our primary back. In that case, the offset
2621 will be zero, as it will be a primary base. */
2623 else
2624 /* The `this' pointer needs to be adjusted from pointing to
2625 BINFO to pointing at the base where the final overrider
2626 appears. */
2637 else
2641 }
2643 /* Called from modify_all_vtables via dfs_walk. */
2645 static tree
2647 {
2649 tree virtuals;
2650 tree old_virtuals;
2654 /* A base without a vtable needs no modification, and its bases
2655 are uninteresting. */
2660 /* Don't do the primary vtable, if it's new. */
2664 /* There's no need to modify the vtable for a non-virtual primary
2665 base; we're not going to use that vtable anyhow. We do still
2666 need to do this for virtual primary bases, as they could become
2667 non-primary in a construction vtable. */
2672 /* Now, go through each of the virtual functions in the virtual
2673 function table for BINFO. Find the final overrider, and update
2674 the BINFO_VIRTUALS list appropriately. */
2677 virtuals;
2681 binfo,
2686 }
2688 /* Update all of the primary and secondary vtables for T. Create new
2689 vtables as required, and initialize their RTTI information. Each
2690 of the functions in VIRTUALS is declared in T and may override a
2691 virtual function from a base class; find and modify the appropriate
2692 entries to point to the overriding functions. Returns a list, in
2693 declaration order, of the virtual functions that are declared in T,
2694 but do not appear in the primary base class vtable, and which
2695 should therefore be appended to the end of the vtable for T. */
2697 static tree
2699 {
2703 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2707 /* Update all of the vtables. */
2710 /* Add virtual functions not already in our primary vtable. These
2711 will be both those introduced by this class, and those overridden
2712 from secondary bases. It does not include virtuals merely
2713 inherited from secondary bases. */
2715 {
2720 {
2721 /* We don't need to adjust the `this' pointer when
2722 calling this function. */
2726 /* This is a function not already in our vtable. Keep it. */
2728 }
2729 else
2730 /* We've already got an entry for this function. Skip it. */
2732 }
2735 }
2737 /* Get the base virtual function declarations in T that have the
2738 indicated NAME. */
2740 static void
2742 {
2745 /* Find virtual functions in T with the indicated NAME. */
2747 {
2751 {
2754 }
2755 }
2762 {
2765 }
2766 }
2768 /* If this declaration supersedes the declaration of
2769 a method declared virtual in the base class, then
2770 mark this field as being virtual as well. */
2772 void
2774 {
2777 /* In [temp.mem] we have:
2779 A specialization of a member function template does not
2780 override a virtual function from a base class. */
2787 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2788 the error_mark_node so that we know it is an overriding
2789 function. */
2790 {
2797 }
2800 {
2806 }
2811 }
2813 /* Warn about hidden virtual functions that are not overridden in t.
2814 We know that constructors and destructors don't apply. */
2816 static void
2818 {
2821 {
2829 tree base_binfo;
2830 tree binfo;
2833 /* Iterate through all of the base classes looking for possibly
2834 hidden functions. */
2837 {
2840 }
2842 /* If there are no functions to hide, continue. */
2846 /* Remove any overridden functions. */
2848 {
2852 {
2853 /* If the method from the base class has the same
2854 signature as the method from the derived class, it
2855 has been overridden. */
2860 }
2861 }
2863 /* Now give a warning for all base functions without overriders,
2864 as they are hidden. */
2865 tree base_fndecl;
2868 {
2869 /* Here we know it is a hider, and no overrider exists. */
2871 OPT_Woverloaded_virtual,
2875 }
2876 }
2877 }
2879 /* Recursive helper for finish_struct_anon. */
2881 static void
2883 {
2887 {
2888 /* We're generally only interested in entities the user
2889 declared, but we also find nested classes by noticing
2890 the TYPE_DECL that we create implicitly. You're
2891 allowed to put one anonymous union inside another,
2892 though, so we explicitly tolerate that. We use
2893 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2894 we also allow unnamed types used for defining fields. */
2901 {
2902 /* We already complained about static data members in
2903 finish_static_data_member_decl. */
2905 {
2908 "%q#D invalid; an anonymous union can "
2910 else
2912 "%q#D invalid; an anonymous struct can "
2914 }
2916 }
2919 {
2921 {
2925 else
2928 }
2930 {
2934 else
2937 }
2938 }
2943 /* Recurse into the anonymous aggregates to handle correctly
2944 access control (c++/24926):
2946 class A {
2947 union {
2948 union {
2949 int i;
2950 };
2951 };
2952 };
2954 int j=A().i; */
2958 }
2959 }
2961 /* Check for things that are invalid. There are probably plenty of other
2962 things we should check for also. */
2964 static void
2966 {
2968 {
2977 }
2978 }
2980 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2981 will be used later during class template instantiation.
2982 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2983 a non-static member data (FIELD_DECL), a member function
2984 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2985 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2986 When FRIEND_P is nonzero, T is either a friend class
2987 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2988 (FUNCTION_DECL, TEMPLATE_DECL). */
2990 void
2992 {
2993 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2998 }
3000 /* This function is called from declare_virt_assop_and_dtor via
3001 dfs_walk_all.
3003 DATA is a type that direcly or indirectly inherits the base
3004 represented by BINFO. If BINFO contains a virtual assignment [copy
3005 assignment or move assigment] operator or a virtual constructor,
3006 declare that function in DATA if it hasn't been already declared. */
3008 static tree
3010 {
3018 /* A base without a vtable needs no modification, and its bases
3019 are uninteresting. */
3023 /* If this is a primary base, then we have already looked at the
3024 virtual functions of its vtable. */
3028 {
3032 {
3037 }
3041 }
3044 }
3046 /* If the class type T has a direct or indirect base that contains a
3047 virtual assignment operator or a virtual destructor, declare that
3048 function in T if it hasn't been already declared. */
3050 static void
3052 {
3060 dfs_declare_virt_assop_and_dtor,
3062 }
3064 /* Declare the inheriting constructor for class T inherited from base
3065 constructor CTOR with the parameter array PARMS of size NPARMS. */
3067 static void
3069 {
3072 /* We don't declare an inheriting ctor that would be a default,
3073 copy or move ctor for derived or base. */
3078 {
3082 }
3091 {
3094 }
3095 }
3097 /* Declare all the inheriting constructors for class T inherited from base
3098 constructor CTOR. */
3100 static void
3102 {
3106 {
3112 }
3117 {
3121 }
3124 {
3128 }
3129 }
3131 /* Create default constructors, assignment operators, and so forth for
3132 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3133 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3134 the class cannot have a default constructor, copy constructor
3135 taking a const reference argument, or an assignment operator taking
3136 a const reference, respectively. */
3138 static void
3142 {
3143 /* Destructor. */
3145 /* In general, we create destructors lazily. */
3154 /* [class.ctor]
3156 If there is no user-declared constructor for a class, a default
3157 constructor is implicitly declared. */
3159 {
3164 /* Don't force the declaration to get a hard answer; if the
3165 definition would have made the class non-literal, it will still be
3166 non-literal because of the base or member in question, and that
3167 gives a better diagnostic. */
3169 }
3171 /* [class.ctor]
3173 If a class definition does not explicitly declare a copy
3174 constructor, one is declared implicitly. */
3176 {
3182 }
3184 /* If there is no assignment operator, one will be created if and
3185 when it is needed. For now, just record whether or not the type
3186 of the parameter to the assignment operator will be a const or
3187 non-const reference. */
3189 {
3195 }
3197 /* We can't be lazy about declaring functions that might override
3198 a virtual function from a base class. */
3202 {
3206 {
3207 /* declare, then remove the decl */
3215 }
3216 else
3218 }
3219 }
3221 /* FIELD is a bit-field. We are finishing the processing for its
3222 enclosing type. Issue any appropriate messages and set appropriate
3223 flags. Returns false if an error has been diagnosed. */
3225 static bool
3227 {
3229 tree w;
3231 /* Extract the declared width of the bitfield, which has been
3232 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3235 /* Remove the bit-field width indicator so that the rest of the
3236 compiler does not treat that value as a qualifier. */
3239 /* Detect invalid bit-field type. */
3241 {
3244 }
3245 else
3246 {
3248 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3251 /* detect invalid field size. */
3257 {
3260 }
3262 {
3265 }
3267 {
3270 }
3285 }
3288 {
3292 }
3293 else
3294 {
3295 /* Non-bit-fields are aligned for their type. */
3299 }
3300 }
3302 /* FIELD is a non bit-field. We are finishing the processing for its
3303 enclosing type T. Issue any appropriate messages and set appropriate
3304 flags. */
3306 static bool
3308 tree t,
3311 {
3315 /* In C++98 an anonymous union cannot contain any fields which would change
3316 the settings of CANT_HAVE_CONST_CTOR and friends. */
3318 ;
3319 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3320 structs. So, we recurse through their fields here. */
3322 {
3327 cant_have_const_ctor,
3328 no_const_asn_ref);
3329 }
3330 /* Check members with class type for constructors, destructors,
3331 etc. */
3333 {
3334 /* Never let anything with uninheritable virtuals
3335 make it through without complaint. */
3339 {
3344 field);
3349 field);
3351 {
3355 }
3356 }
3357 else
3358 {
3371 }
3380 }
3385 /* `build_class_init_list' does not recognize
3386 non-FIELD_DECLs. */
3390 }
3392 /* Check the data members (both static and non-static), class-scoped
3393 typedefs, etc., appearing in the declaration of T. Issue
3394 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3395 declaration order) of access declarations; each TREE_VALUE in this
3396 list is a USING_DECL.
3398 In addition, set the following flags:
3400 EMPTY_P
3401 The class is empty, i.e., contains no non-static data members.
3403 CANT_HAVE_CONST_CTOR_P
3404 This class cannot have an implicitly generated copy constructor
3405 taking a const reference.
3407 CANT_HAVE_CONST_ASN_REF
3408 This class cannot have an implicitly generated assignment
3409 operator taking a const reference.
3411 All of these flags should be initialized before calling this
3412 function.
3414 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3415 fields can be added by adding to this chain. */
3417 static void
3421 {
3429 /* Assume there are no access declarations. */
3431 /* Assume this class has no pointer members. */
3433 /* Assume none of the members of this class have default
3434 initializations. */
3438 {
3446 {
3447 /* Save the access declarations for our caller. */
3450 }
3457 /* FIXME: We should fold in the checking from check_methods. */
3460 /* If we've gotten this far, it's a data member, possibly static,
3461 or an enumerator. */
3465 /* When this goes into scope, it will be a non-local reference. */
3469 {
3470 /* [class.union] (C++98)
3472 If a union contains a static data member, or a member of
3473 reference type, the program is ill-formed.
3475 In C++11 [class.union] says:
3476 If a union contains a non-static data member of reference type
3477 the program is ill-formed. */
3479 {
3483 }
3486 {
3490 }
3491 }
3493 /* Perform error checking that did not get done in
3494 grokdeclarator. */
3496 {
3500 }
3502 {
3506 }
3514 /* Now it can only be a FIELD_DECL. */
3519 /* If at least one non-static data member is non-literal, the whole
3520 class becomes non-literal. Per Core/1453, volatile non-static
3521 data members and base classes are also not allowed.
3522 Note: if the type is incomplete we will complain later on. */
3527 /* A standard-layout class is a class that:
3528 ...
3529 has the same access control (Clause 11) for all non-static data members,
3530 ... */
3537 /* If this is of reference type, check if it needs an init. */
3539 {
3545 {
3546 /* ARM $12.6.2: [A member initializer list] (or, for an
3547 aggregate, initialization by a brace-enclosed list) is the
3548 only way to initialize nonstatic const and reference
3549 members. */
3552 }
3553 }
3558 {
3560 {
3561 warning_at
3564 x);
3566 }
3570 }
3574 /* We don't treat zero-width bitfields as making a class
3575 non-empty. */
3576 ;
3577 else
3578 {
3579 /* The class is non-empty. */
3581 /* The class is not even nearly empty. */
3583 /* If one of the data members contains an empty class,
3584 so does T. */
3588 }
3590 /* This is used by -Weffc++ (see below). Warn only for pointers
3591 to members which might hold dynamic memory. So do not warn
3592 for pointers to functions or pointers to members. */
3598 {
3603 }
3609 {
3611 {
3615 }
3617 {
3621 }
3622 }
3625 /* DR 148 now allows pointers to members (which are POD themselves),
3626 to be allowed in POD structs. */
3635 /* We set DECL_C_BIT_FIELD in grokbitfield.
3636 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3641 {
3646 }
3648 /* Now that we've removed bit-field widths from DECL_INITIAL,
3649 anything left in DECL_INITIAL is an NSDMI that makes the class
3650 non-aggregate in C++11. */
3654 /* If any field is const, the structure type is pseudo-const. */
3656 {
3661 {
3662 /* ARM $12.6.2: [A member initializer list] (or, for an
3663 aggregate, initialization by a brace-enclosed list) is the
3664 only way to initialize nonstatic const and reference
3665 members. */
3668 }
3669 }
3670 /* A field that is pseudo-const makes the structure likewise. */
3672 {
3677 }
3679 /* Core issue 80: A nonstatic data member is required to have a
3680 different name from the class iff the class has a
3681 user-declared constructor. */
3686 }
3688 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3689 it should also define a copy constructor and an assignment operator to
3690 implement the correct copy semantic (deep vs shallow, etc.). As it is
3691 not feasible to check whether the constructors do allocate dynamic memory
3692 and store it within members, we approximate the warning like this:
3694 -- Warn only if there are members which are pointers
3695 -- Warn only if there is a non-trivial constructor (otherwise,
3696 there cannot be memory allocated).
3697 -- Warn only if there is a non-trivial destructor. We assume that the
3698 user at least implemented the cleanup correctly, and a destructor
3699 is needed to free dynamic memory.
3701 This seems enough for practical purposes. */
3703 && has_pointers
3707 {
3711 {
3716 }
3720 }
3722 /* Non-static data member initializers make the default constructor
3723 non-trivial. */
3725 {
3728 }
3730 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3734 /* Check anonymous struct/anonymous union fields. */
3737 /* We've built up the list of access declarations in reverse order.
3738 Fix that now. */
3740 }
3742 /* If TYPE is an empty class type, records its OFFSET in the table of
3743 OFFSETS. */
3745 static int
3747 {
3748 splay_tree_node n;
3753 /* Record the location of this empty object in OFFSETS. */
3761 type,
3765 }
3767 /* Returns nonzero if TYPE is an empty class type and there is
3768 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3770 static int
3772 {
3773 splay_tree_node n;
3774 tree t;
3779 /* Record the location of this empty object in OFFSETS. */
3789 }
3791 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3792 F for every subobject, passing it the type, offset, and table of
3793 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3794 be traversed.
3796 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3797 than MAX_OFFSET will not be walked.
3799 If F returns a nonzero value, the traversal ceases, and that value
3800 is returned. Otherwise, returns zero. */
3802 static int
3804 subobject_offset_fn f,
3805 tree offset,
3806 splay_tree offsets,
3807 tree max_offset,
3809 {
3813 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3814 stop. */
3822 {
3825 }
3828 {
3829 tree field;
3830 tree binfo;
3833 /* Avoid recursing into objects that are not interesting. */
3837 /* Record the location of TYPE. */
3842 /* Iterate through the direct base classes of TYPE. */
3846 {
3847 tree binfo_offset;
3852 tree orig_binfo;
3853 /* We cannot rely on BINFO_OFFSET being set for the base
3854 class yet, but the offsets for direct non-virtual
3855 bases can be calculated by going back to the TYPE. */
3858 offset,
3862 f,
3863 binfo_offset,
3864 offsets,
3865 max_offset,
3869 }
3872 {
3876 /* Iterate through the virtual base classes of TYPE. In G++
3877 3.2, we included virtual bases in the direct base class
3878 loop above, which results in incorrect results; the
3879 correct offsets for virtual bases are only known when
3880 working with the most derived type. */
3884 {
3886 f,
3888 offset,
3890 offsets,
3891 max_offset,
3895 }
3896 else
3897 {
3898 /* We still have to walk the primary base, if it is
3899 virtual. (If it is non-virtual, then it was walked
3900 above.) */
3906 {
3907 r = (walk_subobject_offsets
3912 }
3913 }
3914 }
3916 /* Iterate through the fields of TYPE. */
3921 {
3922 tree field_offset;
3927 f,
3929 offset,
3930 field_offset),
3931 offsets,
3932 max_offset,
3936 }
3937 }
3939 {
3942 tree index;
3944 /* Avoid recursing into objects that are not interesting. */
3947 || !domain
3951 /* Step through each of the elements in the array. */
3955 {
3957 f,
3958 offset,
3959 offsets,
3960 max_offset,
3966 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3967 there's no point in iterating through the remaining
3968 elements of the array. */
3971 }
3972 }
3975 }
3977 /* Record all of the empty subobjects of TYPE (either a type or a
3978 binfo). If IS_DATA_MEMBER is true, then a non-static data member
3979 is being placed at OFFSET; otherwise, it is a base class that is
3980 being placed at OFFSET. */
3982 static void
3984 tree offset,
3985 splay_tree offsets,
3987 {
3988 tree max_offset;
3989 /* If recording subobjects for a non-static data member or a
3990 non-empty base class , we do not need to record offsets beyond
3991 the size of the biggest empty class. Additional data members
3992 will go at the end of the class. Additional base classes will go
3993 either at offset zero (if empty, in which case they cannot
3994 overlap with offsets past the size of the biggest empty class) or
3995 at the end of the class.
3997 However, if we are placing an empty base class, then we must record
3998 all offsets, as either the empty class is at offset zero (where
3999 other empty classes might later be placed) or at the end of the
4000 class (where other objects might then be placed, so other empty
4001 subobjects might later overlap). */
4005 else
4009 }
4011 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4012 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4013 virtual bases of TYPE are examined. */
4015 static int
4017 tree offset,
4018 splay_tree offsets,
4020 {
4021 splay_tree_node max_node;
4023 /* Get the node in OFFSETS that indicates the maximum offset where
4024 an empty subobject is located. */
4026 /* If there aren't any empty subobjects, then there's no point in
4027 performing this check. */
4033 vbases_p);
4034 }
4036 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4037 non-static data member of the type indicated by RLI. BINFO is the
4038 binfo corresponding to the base subobject, OFFSETS maps offsets to
4039 types already located at those offsets. This function determines
4040 the position of the DECL. */
4042 static void
4044 tree decl,
4045 tree binfo,
4046 splay_tree offsets)
4047 {
4050 tree type;
4053 {
4054 /* For the purposes of determining layout conflicts, we want to
4055 use the class type of BINFO; TREE_TYPE (DECL) will be the
4056 CLASSTYPE_AS_BASE version, which does not contain entries for
4057 zero-sized bases. */
4060 }
4061 else
4062 {
4065 }
4067 /* Try to place the field. It may take more than one try if we have
4068 a hard time placing the field without putting two objects of the
4069 same type at the same address. */
4071 {
4074 /* Place this field. */
4078 /* We have to check to see whether or not there is already
4079 something of the same type at the offset we're about to use.
4080 For example, consider:
4082 struct S {};
4083 struct T : public S { int i; };
4084 struct U : public S, public T {};
4086 Here, we put S at offset zero in U. Then, we can't put T at
4087 offset zero -- its S component would be at the same address
4088 as the S we already allocated. So, we have to skip ahead.
4089 Since all data members, including those whose type is an
4090 empty class, have nonzero size, any overlap can happen only
4091 with a direct or indirect base-class -- it can't happen with
4092 a data member. */
4093 /* In a union, overlap is permitted; all members are placed at
4094 offset zero. */
4099 {
4100 /* Strip off the size allocated to this field. That puts us
4101 at the first place we could have put the field with
4102 proper alignment. */
4105 /* Bump up by the alignment required for the type. */
4106 rli->bitpos
4112 }
4115 {
4116 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4117 the offset wasn't aligned like a pointer when we started to
4118 layout this field, that affects its position. */
4121 {
4124 "alignment of %qD increased in -fabi-version=9 "
4126 else
4129 }
4131 }
4132 else
4133 /* There was no conflict. We're done laying out this field. */
4135 }
4137 /* Now that we know where it will be placed, update its
4138 BINFO_OFFSET. */
4140 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4141 this point because their BINFO_OFFSET is copied from another
4142 hierarchy. Therefore, we may not need to add the entire
4143 OFFSET. */
4149 }
4151 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4153 static int
4155 tree offset,
4157 {
4159 }
4161 /* Layout the empty base BINFO. EOC indicates the byte currently just
4162 past the end of the class, and should be correctly aligned for a
4163 class of the type indicated by BINFO; OFFSETS gives the offsets of
4164 the empty bases allocated so far. T is the most derived
4165 type. Return nonzero iff we added it at the end. */
4167 static bool
4170 {
4171 tree alignment;
4175 /* This routine should only be used for empty classes. */
4180 propagate_binfo_offsets
4184 /* This is an empty base class. We first try to put it at offset
4185 zero. */
4188 offsets,
4190 {
4191 /* That didn't work. Now, we move forward from the next
4192 available spot in the class. */
4196 {
4199 offsets,
4201 /* We finally found a spot where there's no overlap. */
4204 /* There's overlap here, too. Bump along to the next spot. */
4206 }
4207 }
4210 {
4215 }
4218 }
4220 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4221 fields at NEXT_FIELD, and return it. */
4223 static tree
4225 {
4226 /* Create the FIELD_DECL. */
4240 /* Add the new FIELD_DECL to the list of fields for T. */
4246 }
4248 /* Layout the base given by BINFO in the class indicated by RLI.
4249 *BASE_ALIGN is a running maximum of the alignments of
4250 any base class. OFFSETS gives the location of empty base
4251 subobjects. T is the most derived type. Return nonzero if the new
4252 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4253 *NEXT_FIELD, unless BINFO is for an empty base class.
4255 Returns the location at which the next field should be inserted. */
4260 {
4265 /* This error is now reported in xref_tag, thus giving better
4266 location information. */
4269 /* Place the base class. */
4271 {
4272 tree decl;
4274 /* The containing class is non-empty because it has a non-empty
4275 base class. */
4278 /* Create the FIELD_DECL. */
4281 /* Try to place the field. It may take more than one try if we
4282 have a hard time placing the field without putting two
4283 objects of the same type at the same address. */
4285 }
4286 else
4287 {
4288 tree eoc;
4291 /* On some platforms (ARM), even empty classes will not be
4292 byte-aligned. */
4297 /* A nearly-empty class "has no proper base class that is empty,
4298 not morally virtual, and at an offset other than zero." */
4300 {
4303 /* The check above (used in G++ 3.2) is insufficient because
4304 an empty class placed at offset zero might itself have an
4305 empty base at a nonzero offset. */
4307 empty_base_at_nonzero_offset_p,
4308 size_zero_node,
4313 }
4315 /* We used to not create a FIELD_DECL for empty base classes because of
4316 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4317 be a problem anymore. We need them to handle initialization of C++17
4318 aggregate bases. */
4320 {
4325 }
4327 /* An empty virtual base causes a class to be non-empty
4328 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4329 here because that was already done when the virtual table
4330 pointer was created. */
4331 }
4333 /* Record the offsets of BINFO and its base subobjects. */
4336 offsets,
4340 }
4342 /* Layout all of the non-virtual base classes. Record empty
4343 subobjects in OFFSETS. T is the most derived type. Return nonzero
4344 if the type cannot be nearly empty. The fields created
4345 corresponding to the base classes will be inserted at
4346 *NEXT_FIELD. */
4348 static void
4351 {
4352 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4353 subobjects. */
4358 /* The primary base class is always allocated first. */
4363 /* Now allocate the rest of the bases. */
4365 {
4366 tree base_binfo;
4370 /* The primary base was already allocated above, so we don't
4371 need to allocate it again here. */
4375 /* Virtual bases are added at the end (a primary virtual base
4376 will have already been added). */
4382 }
4383 }
4385 /* Go through the TYPE_FIELDS of T issuing any appropriate
4386 diagnostics, figuring out which methods override which other
4387 methods, and so forth. */
4389 static void
4391 {
4394 {
4400 /* The name of the field is the original field name
4401 Save this in auxiliary field for later overloading. */
4403 {
4407 }
4409 /* All user-provided destructors are non-trivial.
4410 Constructors and assignment ops are handled in
4411 grok_special_member_properties. */
4418 "%<transaction_safe_dynamic%> may only be specified for "
4420 }
4421 }
4423 /* FN is a constructor or destructor. Clone the declaration to create
4424 a specialized in-charge or not-in-charge version, as indicated by
4425 NAME. */
4427 static tree
4429 {
4430 tree parms;
4431 tree clone;
4433 /* Copy the function. */
4435 /* Reset the function name. */
4437 /* Remember where this function came from. */
4439 /* Make it easy to find the CLONE given the FN. */
4443 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4445 {
4452 }
4453 else
4454 {
4455 // Clone constraints.
4459 }
4464 /* There's no pending inline data for this function. */
4468 /* The base-class destructor is not virtual. */
4470 {
4474 }
4480 /* If there was an in-charge parameter, drop it from the function
4481 type. */
4483 {
4484 tree basetype;
4485 tree parmtypes;
4486 tree exceptions;
4491 /* Skip the `this' parameter. */
4493 /* Skip the in-charge parameter. */
4495 /* And the VTT parm, in a complete [cd]tor. */
4500 {
4501 /* If we're omitting inherited parms, that just leaves the VTT. */
4504 }
4508 parmtypes);
4511 exceptions);
4515 }
4517 /* Copy the function parameters. */
4519 /* Remove the in-charge parameter. */
4521 {
4525 }
4526 /* And the VTT parm, in a complete [cd]tor. */
4528 {
4531 else
4532 {
4536 }
4537 }
4539 /* A base constructor inheriting from a virtual base doesn't get the
4540 arguments. */
4545 {
4548 }
4550 /* Create the RTL for this function. */
4555 }
4557 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4558 not invoke this function directly.
4560 For a non-thunk function, returns the address of the slot for storing
4561 the function it is a clone of. Otherwise returns NULL_TREE.
4563 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4564 cloned_function is unset. This is to support the separate
4565 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4566 on a template makes sense, but not the former. */
4568 tree *
4570 {
4578 {
4579 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4582 else
4583 #endif
4585 }
4590 else
4592 }
4594 /* Produce declarations for all appropriate clones of FN. If
4595 UPDATE_METHODS is true, the clones are added to the
4596 CLASSTYPE_MEMBER_VEC. */
4598 void
4600 {
4601 tree clone;
4603 /* Avoid inappropriate cloning. */
4609 {
4610 /* For each constructor, we need two variants: an in-charge version
4611 and a not-in-charge version. */
4618 }
4619 else
4620 {
4623 /* For each destructor, we need three variants: an in-charge
4624 version, a not-in-charge version, and an in-charge deleting
4625 version. We clone the deleting version first because that
4626 means it will go second on the TYPE_FIELDS list -- and that
4627 corresponds to the correct layout order in the virtual
4628 function table.
4630 For a non-virtual destructor, we do not build a deleting
4631 destructor. */
4633 {
4637 }
4644 }
4646 /* Note that this is an abstract function that is never emitted. */
4648 }
4650 /* DECL is an in charge constructor, which is being defined. This will
4651 have had an in class declaration, from whence clones were
4652 declared. An out-of-class definition can specify additional default
4653 arguments. As it is the clones that are involved in overload
4654 resolution, we must propagate the information from the DECL to its
4655 clones. */
4657 void
4659 {
4660 tree clone;
4664 {
4671 /* Skip the 'this' parameter. */
4687 {
4689 {
4693 }
4699 {
4700 /* A default parameter has been added. Adjust the
4701 clone's parameters. */
4705 tree type;
4710 {
4713 clone_parms);
4715 }
4718 clone_parms);
4727 }
4728 }
4730 }
4731 }
4733 /* For each of the constructors and destructors in T, create an
4734 in-charge and not-in-charge variant. */
4736 static void
4738 {
4739 /* While constructors can be via a using declaration, at this point
4740 we no longer need to know that. */
4746 }
4748 /* Deduce noexcept for a destructor DTOR. */
4750 void
4752 {
4755 noexcept_deferred_spec);
4756 }
4758 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4759 of TYPE for virtual functions which FNDECL overrides. Return a
4760 mask of the tm attributes found therein. */
4762 static int
4764 {
4766 tree base_binfo;
4770 {
4778 {
4782 else
4785 }
4786 else
4788 }
4791 }
4793 /* Subroutine of set_method_tm_attributes. Handle the checks and
4794 inheritance for one virtual method FNDECL. */
4796 static void
4798 {
4799 tree tm_attr;
4804 /* If FNDECL doesn't actually override anything (i.e. T is the
4805 class that first declares FNDECL virtual), then we're done. */
4812 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4813 tm_pure must match exactly, otherwise no weakening of
4814 tm_safe > tm_callable > nothing. */
4815 /* ??? The tm_pure attribute didn't make the transition to the
4816 multivendor language spec. */
4818 {
4820 {
4823 }
4824 }
4825 /* If the overridden function is tm_pure, then FNDECL must be. */
4828 /* Look for base class combinations that cannot be satisfied. */
4830 {
4836 }
4837 /* If FNDECL did not declare an attribute, then inherit the most
4838 restrictive one. */
4840 {
4842 }
4843 /* Otherwise validate that we're not weaker than a function
4844 that is being overridden. */
4845 else
4846 {
4850 }
4853 err_override:
4857 }
4859 /* For each of the methods in T, propagate a class-level tm attribute. */
4861 static void
4863 {
4866 /* Don't bother collecting tm attributes if transactional memory
4867 support is not enabled. */
4871 /* Process virtual methods first, as they inherit directly from the
4872 base virtual function and also require validation of new attributes. */
4874 {
4875 tree vchain;
4878 {
4883 }
4884 }
4886 /* If the class doesn't have an attribute, nothing more to do. */
4891 /* Any method that does not yet have a tm attribute inherits
4892 the one from the class. */
4897 }
4899 /* Returns true if FN is a default constructor. */
4901 bool
4903 {
4906 }
4908 /* Returns true iff class T has a user-defined constructor that can be called
4909 with more than zero arguments. */
4911 bool
4913 {
4918 {
4925 }
4928 }
4930 /* Returns the defaulted constructor if T has one. Otherwise, returns
4931 NULL_TREE. */
4933 tree
4935 {
4940 {
4946 }
4949 }
4951 /* Returns true iff FN is a user-provided function, i.e. user-declared
4952 and not defaulted at its first declaration. */
4954 bool
4956 {
4959 else
4963 }
4965 /* Returns true iff class T has a user-provided constructor. */
4967 bool
4969 {
4981 }
4983 /* Returns true iff class T has a user-provided or explicit constructor. */
4985 bool
4987 {
4995 {
4999 }
5002 }
5004 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5005 declared or explicitly defaulted in the class body) default
5006 constructor. */
5008 bool
5010 {
5017 {
5023 }
5026 }
5028 /* TYPE is being used as a virtual base, and has a non-trivial move
5029 assignment. Return true if this is due to there being a user-provided
5030 move assignment in TYPE or one of its subobjects; if there isn't, then
5031 multiple move assignment can't cause any harm. */
5033 bool
5035 {
5036 /* Does the type itself have a user-provided move assignment operator? */
5044 /* Do any of its bases? */
5046 tree base_binfo;
5051 /* Or non-static data members? */
5053 {
5058 }
5060 /* Seems not. */
5062 }
5064 /* If default-initialization leaves part of TYPE uninitialized, returns
5065 a DECL for the field or TYPE itself (DR 253). */
5067 tree
5069 {
5080 {
5084 }
5089 {
5093 }
5096 }
5098 /* Returns true iff for class T, a trivial synthesized default constructor
5099 would be constexpr. */
5101 bool
5103 {
5104 /* A defaulted trivial default constructor is constexpr
5105 if there is nothing to initialize. */
5108 }
5110 /* Returns true iff class T has a constexpr default constructor. */
5112 bool
5114 {
5115 tree fns;
5118 {
5119 /* The caller should have stripped an enclosing array. */
5122 }
5124 {
5127 /* Non-trivial, we need to check subobject constructors. */
5129 }
5132 }
5134 /* Returns true iff class T has a constexpr default constructor or has an
5135 implicitly declared default constructor that we can't tell if it's constexpr
5136 without forcing a lazy declaration (which might cause undesired
5137 instantiations). */
5139 bool
5141 {
5144 /* Assume it's constexpr. */
5147 }
5149 /* Returns true iff class TYPE has a virtual destructor. */
5151 bool
5153 {
5154 tree dtor;
5162 }
5164 /* Returns true iff T, a class, has a move-assignment or
5165 move-constructor. Does not lazily declare either.
5166 If USER_P is false, any move function will do. If it is true, the
5167 move function must be user-declared.
5169 Note that user-declared here is different from "user-provided",
5170 which doesn't include functions that are defaulted in the
5171 class. */
5173 bool
5175 {
5193 }
5195 /* Nonzero if we need to build up a constructor call when initializing an
5196 object of this class, either because it has a user-declared constructor
5197 or because it doesn't have a default constructor (so we need to give an
5198 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5199 what you care about is whether or not an object can be produced by a
5200 constructor (e.g. so we don't set TREE_READONLY on const variables of
5201 such type); use this function when what you care about is whether or not
5202 to try to call a constructor to create an object. The latter case is
5203 the former plus some cases of constructors that cannot be called. */
5205 bool
5207 {
5208 tree inner;
5218 /* A user-declared constructor might be private, and a constructor might
5219 be trivial but deleted. */
5222 {
5227 }
5229 }
5231 /* Like type_build_ctor_call, but for destructors. */
5233 bool
5235 {
5236 tree inner;
5245 /* A user-declared destructor might be private, and a destructor might
5246 be trivial but deleted. */
5249 {
5254 }
5256 }
5258 /* Remove all zero-width bit-fields from T. */
5260 static void
5262 {
5267 {
5270 /* We should not be confused by the fact that grokbitfield
5271 temporarily sets the width of the bit field into
5272 DECL_BIT_FIELD_REPRESENTATIVE (*fieldsp).
5273 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5274 to that width. */
5278 else
5280 }
5281 }
5283 /* Returns TRUE iff we need a cookie when dynamically allocating an
5284 array whose elements have the indicated class TYPE. */
5286 static bool
5288 {
5289 tree fns;
5294 /* If there's a non-trivial destructor, we need a cookie. In order
5295 to iterate through the array calling the destructor for each
5296 element, we'll have to know how many elements there are. */
5300 /* If the usual deallocation function is a two-argument whose second
5301 argument is of type `size_t', then we have to pass the size of
5302 the array to the deallocation function, so we will need to store
5303 a cookie. */
5307 /* If there are no `operator []' members, or the lookup is
5308 ambiguous, then we don't need a cookie. */
5311 /* Loop through all of the functions. */
5313 {
5316 /* See if this function is a one-argument delete function. If
5317 it is, then it will be the usual deallocation function. */
5321 /* Do not consider this function if its second argument is an
5322 ellipsis. */
5325 /* Otherwise, if we have a two-argument function and the second
5326 argument is `size_t', it will be the usual deallocation
5327 function -- unless there is one-argument function, too. */
5331 }
5334 }
5336 /* Finish computing the `literal type' property of class type T.
5338 At this point, we have already processed base classes and
5339 non-static data members. We need to check whether the copy
5340 constructor is trivial, the destructor is trivial, and there
5341 is a trivial default constructor or at least one constexpr
5342 constructor other than the copy constructor. */
5344 static void
5346 {
5347 tree fn;
5359 /* C++14 DR 1684 removed this restriction. */
5367 {
5371 "enclosing class of %<constexpr%> non-static member "
5374 }
5375 }
5377 /* T is a non-literal type used in a context which requires a constant
5378 expression. Explain why it isn't literal. */
5380 void
5382 {
5392 /* Already explained. */
5398 " %qT is a closure type, which is only literal in "
5406 {
5408 " %q+T is not an aggregate, does not have a trivial "
5409 "default constructor, and has no %<constexpr%> constructor that "
5412 /* Note that we can't simply call locate_ctor because when the
5413 constructor is deleted it just returns NULL_TREE. */
5415 {
5422 {
5425 else
5428 }
5429 }
5430 }
5431 else
5432 {
5436 {
5439 {
5445 }
5446 }
5448 {
5449 tree ftype;
5454 {
5457 field);
5460 }
5464 }
5465 }
5466 }
5468 /* Check the validity of the bases and members declared in T. Add any
5469 implicitly-generated functions (like copy-constructors and
5470 assignment operators). Compute various flag bits (like
5471 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5472 level: i.e., independently of the ABI in use. */
5474 static void
5476 {
5477 /* Nonzero if the implicitly generated copy constructor should take
5478 a non-const reference argument. */
5480 /* Nonzero if the implicitly generated assignment operator
5481 should take a non-const reference argument. */
5483 tree access_decls;
5486 tree fn;
5488 /* By default, we use const reference arguments and generate default
5489 constructors. */
5493 /* Check all the base-classes and set FMEM members to point to arrays
5494 of potential interest. */
5497 /* Deduce noexcept on destructor. This needs to happen after we've set
5498 triviality flags appropriately for our bases. */
5503 /* Check all the method declarations. */
5506 /* Save the initial values of these flags which only indicate whether
5507 or not the class has user-provided functions. As we analyze the
5508 bases and members we can set these flags for other reasons. */
5512 /* Check all the data member declarations. We cannot call
5513 check_field_decls until we have called check_bases check_methods,
5514 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5515 being set appropriately. */
5520 /* A nearly-empty class has to be vptr-containing; a nearly empty
5521 class contains just a vptr. */
5525 /* Do some bookkeeping that will guide the generation of implicitly
5526 declared member functions. */
5529 /* We need to call a constructor for this class if it has a
5530 user-provided constructor, or if the default constructor is going
5531 to initialize the vptr. (This is not an if-and-only-if;
5532 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5533 themselves need constructing.) */
5536 /* [dcl.init.aggr]
5538 An aggregate is an array or a class with no user-provided
5539 constructors ... and no virtual functions.
5541 Again, other conditions for being an aggregate are checked
5542 elsewhere. */
5546 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5547 retain the old definition internally for ABI reasons. */
5556 /* If the only explicitly declared default constructor is user-provided,
5557 set TYPE_HAS_COMPLEX_DFLT. */
5563 /* Warn if a public base of a polymorphic type has an accessible
5564 non-virtual destructor. It is only now that we know the class is
5565 polymorphic. Although a polymorphic base will have a already
5566 been diagnosed during its definition, we warn on use too. */
5568 {
5571 tree base_binfo;
5575 {
5583 basetype);
5584 }
5585 }
5587 /* If the class has no user-declared constructor, but does have
5588 non-static const or reference data members that can never be
5589 initialized, issue a warning. */
5591 /* Classes with user-declared constructors are presumed to
5592 initialize these members. */
5594 /* Aggregates can be initialized with brace-enclosed
5595 initializers. */
5597 {
5598 tree field;
5601 {
5602 tree type;
5619 }
5620 }
5622 /* Synthesize any needed methods. */
5624 cant_have_const_ctor,
5625 no_const_asn_ref);
5627 /* Check defaulted declarations here so we have cant_have_const_ctor
5628 and don't need to worry about clones. */
5633 {
5636 {
5637 bool imp_const_p
5643 /* If the function is defaulted outside the class, we just
5644 give the synthesis error. */
5647 }
5649 }
5652 {
5653 /* "This class type is not an aggregate." */
5655 }
5657 /* Compute the 'literal type' property before we
5658 do anything with non-static member functions. */
5661 /* Create the in-charge and not-in-charge variants of constructors
5662 and destructors. */
5665 /* Process the using-declarations. */
5669 /* Figure out whether or not we will need a cookie when dynamically
5670 allocating an array of this type. */
5673 }
5675 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5676 accordingly. If a new vfield was created (because T doesn't have a
5677 primary base class), then the newly created field is returned. It
5678 is not added to the TYPE_FIELDS list; it is the caller's
5679 responsibility to do that. Accumulate declared virtual functions
5680 on VIRTUALS_P. */
5682 static tree
5684 {
5685 tree fn;
5687 /* Collect the virtual functions declared in T. */
5692 {
5701 }
5703 /* If we couldn't find an appropriate base class, create a new field
5704 here. Even if there weren't any new virtual functions, we might need a
5705 new virtual function table if we're supposed to include vptrs in
5706 all classes that need them. */
5708 {
5709 /* We build this decl with vtbl_ptr_type_node, which is a
5710 `vtable_entry_type*'. It might seem more precise to use
5711 `vtable_entry_type (*)[N]' where N is the number of virtual
5712 functions. However, that would require the vtable pointer in
5713 base classes to have a different type than the vtable pointer
5714 in derived classes. We could make that happen, but that
5715 still wouldn't solve all the problems. In particular, the
5716 type-based alias analysis code would decide that assignments
5717 to the base class vtable pointer can't alias assignments to
5718 the derived class vtable pointer, since they have different
5719 types. Thus, in a derived class destructor, where the base
5720 class constructor was inlined, we could generate bad code for
5721 setting up the vtable pointer.
5723 Therefore, we use one type for all vtable pointers. We still
5724 use a type-correct type; it's just doesn't indicate the array
5725 bounds. That's better than using `void*' or some such; it's
5726 cleaner, and it let's the alias analysis code know that these
5727 stores cannot alias stores to void*! */
5728 tree field;
5741 /* This class is non-empty. */
5745 }
5748 }
5750 /* Add OFFSET to all base types of BINFO which is a base in the
5751 hierarchy dominated by T.
5753 OFFSET, which is a type offset, is number of bytes. */
5755 static void
5757 {
5759 tree primary_binfo;
5760 tree base_binfo;
5762 /* Update BINFO's offset. */
5767 offset));
5769 /* Find the primary base class. */
5775 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5776 downwards. */
5778 {
5779 /* Don't do the primary base twice. */
5787 }
5788 }
5790 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5791 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5792 empty subobjects of T. */
5794 static void
5796 {
5797 tree vbase;
5804 /* Find the last field. The artificial fields created for virtual
5805 bases will go after the last extant field to date. */
5810 /* Go through the virtual bases, allocating space for each virtual
5811 base that is not already a primary base class. These are
5812 allocated in inheritance graph order. */
5814 {
5819 {
5820 /* This virtual base is not a primary base of any class in the
5821 hierarchy, so we have to add space for it. */
5824 }
5825 }
5826 }
5828 /* Returns the offset of the byte just past the end of the base class
5829 BINFO. */
5831 static tree
5833 {
5834 tree size;
5839 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5840 allocate some space for it. It cannot have virtual bases, so
5841 TYPE_SIZE_UNIT is fine. */
5843 else
5847 }
5849 /* Returns the offset of the byte just past the end of the base class
5850 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
5851 only non-virtual bases are included. */
5853 static tree
5855 {
5858 tree binfo;
5859 tree base_binfo;
5860 tree offset;
5865 {
5875 }
5880 {
5884 }
5887 }
5889 /* Warn about bases of T that are inaccessible because they are
5890 ambiguous. For example:
5892 struct S {};
5893 struct T : public S {};
5894 struct U : public S, public T {};
5896 Here, `(S*) new U' is not allowed because there are two `S'
5897 subobjects of U. */
5899 static void
5901 {
5904 tree basetype;
5905 tree binfo;
5906 tree base_binfo;
5908 /* If there are no repeated bases, nothing can be ambiguous. */
5912 /* Check direct bases. */
5915 {
5921 }
5923 /* Check for ambiguous virtual bases. */
5927 {
5933 }
5934 }
5936 /* Compare two INTEGER_CSTs K1 and K2. */
5938 static int
5940 {
5942 }
5944 /* Increase the size indicated in RLI to account for empty classes
5945 that are "off the end" of the class. */
5947 static void
5949 {
5950 tree eoc;
5951 tree rli_size;
5953 /* It might be the case that we grew the class to allocate a
5954 zero-sized base class. That won't be reflected in RLI, yet,
5955 because we are willing to overlay multiple bases at the same
5956 offset. However, now we need to make sure that RLI is big enough
5957 to reflect the entire class. */
5962 {
5963 /* The size should have been rounded to a whole byte. */
5966 rli->bitpos
5975 }
5976 }
5978 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
5979 BINFO_OFFSETs for all of the base-classes. Position the vtable
5980 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
5982 static void
5984 {
5985 tree non_static_data_members;
5986 tree field;
5987 tree vptr;
5988 record_layout_info rli;
5989 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
5990 types that appear at that offset. */
5991 splay_tree empty_base_offsets;
5992 /* True if the last field laid out was a bit-field. */
5994 /* The location at which the next field should be inserted. */
5997 /* Keep track of the first non-static data member. */
6000 /* Start laying out the record. */
6003 /* Mark all the primary bases in the hierarchy. */
6006 /* Create a pointer to our virtual function table. */
6009 /* The vptr is always the first thing in the class. */
6011 {
6016 }
6017 else
6020 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6025 /* Layout the non-static data members. */
6027 {
6028 tree type;
6029 tree padding;
6031 /* We still pass things that aren't non-static data members to
6032 the back end, in case it wants to do something with them. */
6034 {
6036 /* If the static data member has incomplete type, keep track
6037 of it so that it can be completed later. (The handling
6038 of pending statics in finish_record_layout is
6039 insufficient; consider:
6041 struct S1;
6042 struct S2 { static S1 s1; };
6044 At this point, finish_record_layout will be called, but
6045 S1 is still incomplete.) */
6047 {
6049 /* The visibility of static data members is determined
6050 at their point of declaration, not their point of
6051 definition. */
6053 }
6055 }
6063 /* If this field is a bit-field whose width is greater than its
6064 type, then there are some special rules for allocating
6065 it. */
6068 {
6070 /* We must allocate the bits as if suitably aligned for the
6071 longest integer type that fits in this many bits. Then,
6072 we are supposed to use the left over bits as additional
6073 padding. */
6075 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6083 {
6085 /* Too big, so our current guess is what we want. */
6087 /* Not bigger than limit, ok */
6089 }
6091 /* Figure out how much additional padding is required. */
6093 /* In a union, the padding field must have the full width
6094 of the bit-field; all fields start at offset zero. */
6096 else
6103 /* An unnamed bitfield does not normally affect the
6104 alignment of the containing class on a target where
6105 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6106 make any exceptions for unnamed bitfields when the
6107 bitfields are longer than their types. Therefore, we
6108 temporarily give the field a name. */
6110 {
6113 }
6119 empty_base_offsets);
6122 /* Now that layout has been performed, set the size of the
6123 field to the size of its declared type; the rest of the
6124 field is effectively invisible. */
6126 /* We must also reset the DECL_MODE of the field. */
6128 }
6129 else
6131 empty_base_offsets);
6133 /* Remember the location of any empty classes in FIELD. */
6136 empty_base_offsets,
6139 /* If a bit-field does not immediately follow another bit-field,
6140 and yet it starts in the middle of a byte, we have failed to
6141 comply with the ABI. */
6144 /* The TREE_NO_WARNING flag gets set by Objective-C when
6145 laying out an Objective-C class. The ObjC ABI differs
6146 from the C++ ABI, and so we do not want a warning
6147 here. */
6149 && !last_field_was_bitfield
6152 bitsize_unit_node)))
6154 "offset of %qD is not ABI-compliant and may "
6157 /* The middle end uses the type of expressions to determine the
6158 possible range of expression values. In order to optimize
6159 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6160 must be made aware of the width of "i", via its type.
6162 Because C++ does not have integer types of arbitrary width,
6163 we must (for the purposes of the front end) convert from the
6164 type assigned here to the declared type of the bitfield
6165 whenever a bitfield expression is used as an rvalue.
6166 Similarly, when assigning a value to a bitfield, the value
6167 must be converted to the type given the bitfield here. */
6169 {
6174 {
6181 }
6182 }
6184 /* If we needed additional padding after this field, add it
6185 now. */
6187 {
6188 tree padding_field;
6191 FIELD_DECL,
6192 NULL_TREE,
6193 char_type_node);
6201 NULL_TREE,
6202 empty_base_offsets);
6203 }
6206 }
6209 {
6210 /* Make sure that we are on a byte boundary so that the size of
6211 the class without virtual bases will always be a round number
6212 of bytes. */
6215 }
6217 /* Delete all zero-width bit-fields from the list of fields. Now
6218 that the type is laid out they are no longer important. */
6222 {
6223 /* T needs a different layout as a base (eliding virtual bases
6224 or whatever). Create that version. */
6227 /* If the ABI version is not at least two, and the last
6228 field was a bit-field, RLI may not be on a byte
6229 boundary. In particular, rli_size_unit_so_far might
6230 indicate the last complete byte, while rli_size_so_far
6231 indicates the total number of bits used. Therefore,
6232 rli_size_so_far, rather than rli_size_unit_so_far, is
6233 used to compute TYPE_SIZE_UNIT. */
6241 eoc);
6251 /* Copy the non-static data members of T. This will include its
6252 direct non-virtual bases & vtable. */
6256 {
6260 }
6263 /* We use the base type for trivial assignments, and hence it
6264 needs a mode. */
6269 /* Record the base version of the type. */
6271 }
6272 else
6275 /* Every empty class contains an empty class. */
6279 /* Set the TYPE_DECL for this type to contain the right
6280 value for DECL_OFFSET, so that we can use it as part
6281 of a COMPONENT_REF for multiple inheritance. */
6284 /* Now fix up any virtual base class types that we left lying
6285 around. We must get these done before we try to lay out the
6286 virtual function table. As a side-effect, this will remove the
6287 base subobject fields. */
6290 /* Make sure that empty classes are reflected in RLI at this
6291 point. */
6294 /* Make sure not to create any structures with zero size. */
6300 /* If this is a non-POD, declaring it packed makes a difference to how it
6301 can be used as a field; don't let finalize_record_size undo it. */
6305 /* Let the back end lay out the type. */
6314 /* Warn about bases that can't be talked about due to ambiguity. */
6317 /* Now that we're done with layout, give the base fields the real types. */
6322 /* Clean up. */
6329 }
6331 /* Determine the "key method" for the class type indicated by TYPE,
6332 and set CLASSTYPE_KEY_METHOD accordingly. */
6334 void
6336 {
6337 tree method;
6344 /* The key method is the first non-pure virtual function that is not
6345 inline at the point of class definition. On some targets the
6346 key function may not be inline; those targets should not call
6347 this function until the end of the translation unit. */
6353 {
6356 }
6359 }
6361 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6362 class data member of non-zero size, otherwise false. */
6366 {
6374 {
6378 }
6381 }
6383 /* Used by find_flexarrays and related functions. */
6385 struct flexmems_t
6386 {
6387 /* The first flexible array member or non-zero array member found
6388 in the order of layout. */
6389 tree array;
6390 /* First non-static non-empty data member in the class or its bases. */
6391 tree first;
6392 /* The first non-static non-empty data member following either
6393 the flexible array member, if found, or the zero-length array member
6394 otherwise. AFTER[1] refers to the first such data member of a union
6395 of which the struct containing the flexible array member or zero-length
6396 array is a member, or NULL when no such union exists. This element is
6397 only used during searching, not for diagnosing problems. AFTER[0]
6398 refers to the first such data member that is not a member of such
6399 a union. */
6402 /* Refers to a struct (not union) in which the struct of which the flexible
6403 array is member is defined. Used to diagnose strictly (according to C)
6404 invalid uses of the latter structs. */
6405 tree enclosing;
6406 };
6408 /* Find either the first flexible array member or the first zero-length
6409 array, in that order of preference, among members of class T (but not
6410 its base classes), and set members of FMEM accordingly.
6411 BASE_P is true if T is a base class of another class.
6412 PUN is set to the outermost union in which the flexible array member
6413 (or zero-length array) is defined if one such union exists, otherwise
6414 to NULL.
6415 Similarly, PSTR is set to a data member of the outermost struct of
6416 which the flexible array is a member if one such struct exists,
6417 otherwise to NULL. */
6419 static void
6423 {
6424 /* Set the "pointer" to the outermost enclosing union if not set
6425 yet and maintain it for the remainder of the recursion. */
6430 {
6434 /* Is FLD a typedef for an anonymous struct? */
6436 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6437 handled elsewhere so that errors like the following are detected
6438 as well:
6439 typedef struct { int i, a[], j; } S; // bug c++/72753
6440 S s [2]; // bug c++/68489
6441 */
6446 {
6447 /* Check the nested unnamed type referenced via a typedef
6448 independently of FMEM (since it's not a data member of
6449 the enclosing class). */
6452 }
6454 /* Skip anything that's GCC-generated or not a (non-static) data
6455 member. */
6459 /* Type of the member. */
6464 /* Determine the type of the array element or object referenced
6465 by the member so that it can be checked for flexible array
6466 members if it hasn't been yet. */
6474 {
6476 {
6477 /* Once the member after the flexible array has been found
6478 we're done. */
6481 }
6484 {
6485 /* Descend into the non-static member struct or union and try
6486 to find a flexible array member or zero-length array among
6487 its members. This is only necessary for anonymous types
6488 and types in whose context the current type T has not been
6489 defined (the latter must not be checked again because they
6490 are already in the process of being checked by one of the
6491 recursive calls). */
6496 /* If this member isn't anonymous and a prior non-flexible array
6497 member has been seen in one of the enclosing structs, clear
6498 the FIRST member since it doesn't contribute to the flexible
6499 array struct's members. */
6510 {
6511 /* Restore the FIRST member reset above if no flexible
6512 array member has been found in this member's struct. */
6514 }
6516 /* If the member struct contains the first flexible array
6517 member, or if this member is a base class, continue to
6518 the next member and avoid setting the FMEM->NEXT pointer
6519 to point to it. */
6522 }
6523 }
6526 {
6527 /* Remember the first non-static data member. */
6531 /* Remember the first non-static data member after the flexible
6532 array member, if one has been found, or the zero-length array
6533 if it has been found. */
6536 }
6538 /* Skip non-arrays. */
6542 /* Determine the upper bound of the array if it has one. */
6544 {
6546 {
6547 /* Make a record of the zero-length array if either one
6548 such field or a flexible array member has been seen to
6549 handle the pathological and unlikely case of multiple
6550 such members. */
6553 }
6555 {
6556 /* Remember the first zero-length array unless a flexible array
6557 member has already been seen. */
6560 }
6561 }
6562 else
6563 {
6564 /* Flexible array members have no upper bound. */
6566 {
6567 /* Replace the zero-length array if it's been stored and
6568 reset the after pointer. */
6570 {
6574 }
6575 }
6576 else
6577 {
6580 }
6581 }
6582 }
6583 }
6585 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6586 a flexible array member (or the zero-length array extension). */
6588 static void
6590 {
6602 }
6604 /* Issue diagnostics for invalid flexible array members or zero-length
6605 arrays that are not the last elements of the containing class or its
6606 base classes or that are its sole members. */
6608 static void
6610 {
6615 {
6618 }
6620 /* Has a diagnostic been issued? */
6626 {
6633 {
6637 {
6640 }
6641 }
6642 }
6643 else
6644 {
6651 {
6657 /* In the unlikely event that the member following the flexible
6658 array member is declared in a different class, or the member
6659 overlaps another member of a common union, point to it.
6660 Otherwise it should be obvious. */
6664 {
6669 }
6670 }
6671 }
6675 }
6678 /* Recursively check to make sure that any flexible array or zero-length
6679 array members of class T or its bases are valid (i.e., not the sole
6680 non-static data member of T and, if one exists, that it is the last
6681 non-static data member of T and its base classes. FMEM is expected
6682 to be initially null and is used internally by recursive calls to
6683 the function. Issue the appropriate diagnostics for the array member
6684 that fails the checks. */
6686 static void
6689 {
6690 /* Initialize the result of a search for flexible array and zero-length
6691 array members. Avoid doing any work if the most interesting FMEM data
6692 have already been populated. */
6701 /* Recursively check the primary base class first. */
6703 {
6706 }
6708 /* Recursively check the base classes. */
6711 {
6714 /* The primary base class was already checked above. */
6718 /* Virtual base classes are at the end. */
6722 /* Check the base class. */
6724 }
6727 {
6728 /* Check virtual base classes only once per derived class.
6729 I.e., this check is not performed recursively for base
6730 classes. */
6732 tree base_binfo;
6736 {
6737 /* Check the virtual base class. */
6741 }
6742 }
6744 /* Is the type unnamed (and therefore a member of it potentially
6745 an anonymous struct or union)? */
6748 /* Search the members of the current (possibly derived) class, skipping
6749 unnamed structs and unions since those could be anonymous. */
6754 {
6755 /* Issue diagnostics for invalid flexible and zero-length array
6756 members found in base classes or among the members of the current
6757 class. Ignore anonymous structs and unions whose members are
6758 considered to be members of the enclosing class and thus will
6759 be diagnosed when checking it. */
6761 }
6762 }
6764 /* Perform processing required when the definition of T (a class type)
6765 is complete. Diagnose invalid definitions of flexible array members
6766 and zero-size arrays. */
6768 void
6770 {
6771 tree x;
6772 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6776 {
6781 }
6783 /* If this type was previously laid out as a forward reference,
6784 make sure we lay it out again. */
6788 /* Make assumptions about the class; we'll reset the flags if
6789 necessary. */
6795 /* Do end-of-class semantic processing: checking the validity of the
6796 bases and members and add implicitly generated methods. */
6799 /* Find the key method. */
6801 {
6802 /* The Itanium C++ ABI permits the key method to be chosen when
6803 the class is defined -- even though the key method so
6804 selected may later turn out to be an inline function. On
6805 some systems (such as ARM Symbian OS) the key method cannot
6806 be determined until the end of the translation unit. On such
6807 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6808 will cause the class to be added to KEYED_CLASSES. Then, in
6809 finish_file we will determine the key method. */
6813 /* If a polymorphic class has no key method, we may emit the vtable
6814 in every translation unit where the class definition appears. If
6815 we're devirtualizing, we can look into the vtable even if we
6816 aren't emitting it. */
6819 }
6821 /* Layout the class itself. */
6823 /* COMPLETE_TYPE_P is now true. */
6827 /* With the layout complete, check for flexible array members and
6828 zero-length arrays that might overlap other members in the final
6829 layout. */
6834 /* If necessary, create the primary vtable for this class. */
6836 {
6837 /* We must enter these virtuals into the table. */
6841 /* Here we know enough to change the type of our virtual
6842 function table, but we will wait until later this function. */
6845 /* If we're warning about ABI tags, check the types of the new
6846 virtual functions. */
6850 }
6853 {
6855 tree fn;
6862 /* Add entries for virtual functions introduced by this class. */
6866 /* Set DECL_VINDEX for all functions declared in this class. */
6868 fn;
6870 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6872 {
6876 /* A thunk. We should never be calling this entry directly
6877 from this vtable -- we'd use the entry for the non
6878 thunk base function. */
6882 }
6883 }
6891 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
6892 for any static member objects of the type we're working on. */
6901 /* Complain if one of the field types requires lower visibility. */
6904 /* Make the rtl for any new vtables we have created, and unmark
6905 the base types we marked. */
6908 /* Build the VTT for T. */
6915 "%q#T has virtual functions and accessible"
6923 /* Class layout, assignment of virtual table slots, etc., is now
6924 complete. Give the back end a chance to tweak the visibility of
6925 the class or perform any other required target modifications. */
6935 /* Finish debugging output for this type. */
6939 {
6942 {
6945 }
6947 {
6950 else
6951 {
6954 }
6956 }
6958 {
6960 "the type of the first field has a different ABI from the "
6963 }
6964 }
6965 }
6967 /* When T was built up, the member declarations were added in reverse
6968 order. Rearrange them to declaration order. */
6970 void
6972 {
6973 tree next;
6974 tree prev;
6975 tree x;
6977 /* The following lists are all in reverse order. Put them in
6978 declaration order now. */
6981 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
6982 order, so we can't just use nreverse. Due to stat_hack
6983 chicanery in finish_member_declaration. */
6988 {
6992 }
6995 {
6998 }
6999 }
7001 tree
7003 {
7006 /* Now that we've got all the field declarations, reverse everything
7007 as necessary. */
7013 /* Nadger the current location so that diagnostics point to the start of
7014 the struct, not the end. */
7018 {
7019 tree x;
7021 /* We need to add the target functions of USING_DECLS, so that
7022 they can be found when the using declaration is not
7023 instantiated yet. */
7026 {
7031 }
7037 /* COMPLETE_TYPE_P is now true. */
7041 /* We need to emit an error message if this type was used as a parameter
7042 and it is an abstract type, even if it is a template. We construct
7043 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7044 account and we call complete_vars with this type, which will check
7045 the PARM_DECLS. Note that while the type is being defined,
7046 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7047 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7054 /* Remember current #pragma pack value. */
7057 /* Fix up any variants we've already built. */
7059 {
7063 }
7064 }
7065 else
7067 /* COMPLETE_TYPE_P is now true. */
7072 {
7073 /* People keep complaining that the compiler crashes on an invalid
7074 definition of initializer_list, so I guess we should explicitly
7075 reject it. What the compiler internals care about is that it's a
7076 template and has a pointer field followed by an integer field. */
7079 {
7082 {
7086 }
7087 }
7090 "definition of std::initializer_list does not match "
7092 }
7100 else
7104 /* Lambdas are defined by the LAMBDA_EXPR. */
7109 }
7110 \f
7111 /* Hash table to avoid endless recursion when handling references. */
7114 /* Return the dynamic type of INSTANCE, if known.
7115 Used to determine whether the virtual function table is needed
7116 or not.
7118 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7119 of our knowledge of its type. *NONNULL should be initialized
7120 before this function is called. */
7122 static tree
7124 {
7125 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7128 {
7132 else
7136 /* This is a call to a constructor, hence it's never zero. */
7138 {
7142 }
7146 /* This is a call to a constructor, hence it's never zero. */
7148 {
7152 }
7161 /* Propagate nonnull. */
7166 CASE_CONVERT:
7172 {
7173 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7174 with a real object -- given &p->f, p can still be null. */
7176 /* ??? Probably should check DECL_WEAK here. */
7179 }
7183 /* If this component is really a base class reference, then the field
7184 itself isn't definitive. */
7193 {
7197 }
7198 /* fall through. */
7203 {
7207 }
7209 {
7213 /* if we're in a ctor or dtor, we know our type. If
7214 current_class_ptr is set but we aren't in a function, we're in
7215 an NSDMI (and therefore a constructor). */
7220 {
7224 }
7225 }
7227 {
7228 /* We only need one hash table because it is always left empty. */
7230 fixed_type_or_null_ref_ht
7233 /* Reference variables should be references to objects. */
7237 /* Enter the INSTANCE in a table to prevent recursion; a
7238 variable's initializer may refer to the variable
7239 itself. */
7244 {
7245 tree type;
7254 }
7255 }
7260 }
7261 #undef RECUR
7262 }
7264 /* Return nonzero if the dynamic type of INSTANCE is known, and
7265 equivalent to the static type. We also handle the case where
7266 INSTANCE is really a pointer. Return negative if this is a
7267 ctor/dtor. There the dynamic type is known, but this might not be
7268 the most derived base of the original object, and hence virtual
7269 bases may not be laid out according to this type.
7271 Used to determine whether the virtual function table is needed
7272 or not.
7274 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7275 of our knowledge of its type. *NONNULL should be initialized
7276 before this function is called. */
7278 int
7280 {
7283 tree fixed;
7285 /* processing_template_decl can be false in a template if we're in
7286 instantiate_non_dependent_expr, but we still want to suppress
7287 this check. */
7289 {
7290 /* In a template we only care about the type of the result. */
7294 }
7304 }
7306 \f
7307 void
7309 {
7312 current_class_stack
7320 }
7322 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7324 static void
7326 {
7327 tree type;
7329 /* We are re-entering the same class we just left, so we don't
7330 have to search the whole inheritance matrix to find all the
7331 decls to bind again. Instead, we install the cached
7332 class_shadowed list and walk through it binding names. */
7335 /* Restore IDENTIFIER_TYPE_VALUE. */
7337 type;
7340 }
7342 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7343 appropriate for TYPE.
7345 So that we may avoid calls to lookup_name, we cache the _TYPE
7346 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7348 For multiple inheritance, we perform a two-pass depth-first search
7349 of the type lattice. */
7351 void
7353 {
7354 class_stack_node_t csn;
7358 /* Make sure there is enough room for the new entry on the stack. */
7360 {
7362 current_class_stack
7364 current_class_stack_size);
7365 }
7367 /* Insert a new entry on the class stack. */
7374 current_class_depth++;
7376 /* Now set up the new type. */
7382 /* By default, things in classes are private, while things in
7383 structures or unions are public. */
7385 ? access_private_node
7391 {
7392 /* Forcibly remove any old class remnants. */
7394 }
7400 else
7402 }
7404 /* When we exit a toplevel class scope, we save its binding level so
7405 that we can restore it quickly. Here, we've entered some other
7406 class, so we must invalidate our cache. */
7408 void
7410 {
7412 }
7414 /* Get out of the current class scope. If we were in a class scope
7415 previously, that is the one popped to. */
7417 void
7419 {
7422 current_class_depth--;
7428 }
7430 /* Mark the top of the class stack as hidden. */
7432 void
7434 {
7437 }
7439 /* Mark the top of the class stack as un-hidden. */
7441 void
7443 {
7446 }
7448 /* Returns 1 if the class type currently being defined is either T or
7449 a nested type of T. Returns the type from the current_class_stack,
7450 which might be equivalent to but not equal to T in case of
7451 constrained partial specializations. */
7453 tree
7455 {
7463 /* We start looking from 1 because entry 0 is from global scope,
7464 and has no type. */
7466 {
7467 tree c;
7470 else
7471 {
7475 }
7480 }
7482 }
7484 /* If either current_class_type or one of its enclosing classes are derived
7485 from T, return the appropriate type. Used to determine how we found
7486 something via unqualified lookup. */
7488 tree
7490 {
7493 /* The bases of a dependent type are unknown. */
7504 {
7509 }
7512 }
7514 /* Return the outermost enclosing class type that is still open, or
7515 NULL_TREE. */
7517 tree
7519 {
7526 {
7533 }
7535 }
7537 /* Returns the innermost class type which is not a lambda closure type. */
7539 tree
7541 {
7546 }
7548 /* When entering a class scope, all enclosing class scopes' names with
7549 static meaning (static variables, static functions, types and
7550 enumerators) have to be visible. This recursive function calls
7551 pushclass for all enclosing class contexts until global or a local
7552 scope is reached. TYPE is the enclosed class. */
7554 void
7556 {
7557 /* A namespace might be passed in error cases, like A::B:C. */
7565 }
7567 /* Undoes a push_nested_class call. */
7569 void
7571 {
7577 }
7579 /* Returns the number of extern "LANG" blocks we are nested within. */
7581 int
7583 {
7585 }
7587 /* Set global variables CURRENT_LANG_NAME to appropriate value
7588 so that behavior of name-mangling machinery is correct. */
7590 void
7592 {
7599 else
7601 }
7603 /* Get out of the current language scope. */
7605 void
7607 {
7609 }
7610 \f
7611 /* Type instantiation routines. */
7613 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7614 matches the TARGET_TYPE. If there is no satisfactory match, return
7615 error_mark_node, and issue an error & warning messages under
7616 control of FLAGS. Permit pointers to member function if FLAGS
7617 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7618 a template-id, and EXPLICIT_TARGS are the explicitly provided
7619 template arguments.
7621 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7622 is the base path used to reference those member functions. If
7623 the address is resolved to a member function, access checks will be
7624 performed and errors issued if appropriate. */
7626 static tree
7628 tree overload,
7629 tsubst_flags_t complain,
7631 tree explicit_targs,
7632 tree access_path)
7633 {
7634 /* Here's what the standard says:
7636 [over.over]
7638 If the name is a function template, template argument deduction
7639 is done, and if the argument deduction succeeds, the deduced
7640 arguments are used to generate a single template function, which
7641 is added to the set of overloaded functions considered.
7643 Non-member functions and static member functions match targets of
7644 type "pointer-to-function" or "reference-to-function." Nonstatic
7645 member functions match targets of type "pointer-to-member
7646 function;" the function type of the pointer to member is used to
7647 select the member function from the set of overloaded member
7648 functions. If a nonstatic member function is selected, the
7649 reference to the overloaded function name is required to have the
7650 form of a pointer to member as described in 5.3.1.
7652 If more than one function is selected, any template functions in
7653 the set are eliminated if the set also contains a non-template
7654 function, and any given template function is eliminated if the
7655 set contains a second template function that is more specialized
7656 than the first according to the partial ordering rules 14.5.5.2.
7657 After such eliminations, if any, there shall remain exactly one
7658 selected function. */
7661 /* We store the matches in a TREE_LIST rooted here. The functions
7662 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7663 interoperability with most_specialized_instantiation. */
7665 tree fn;
7666 tree target_fn_type;
7668 /* By the time we get here, we should be seeing only real
7669 pointer-to-member types, not the internal POINTER_TYPE to
7670 METHOD_TYPE representation. */
7676 /* Check that the TARGET_TYPE is reasonable. */
7681 /* This is OK, too. */
7684 /* This is OK, too. This comes from a conversion to reference
7685 type. */
7687 else
7688 {
7694 }
7696 /* Non-member functions and static member functions match targets of type
7697 "pointer-to-function" or "reference-to-function." Nonstatic member
7698 functions match targets of type "pointer-to-member-function;" the
7699 function type of the pointer to member is used to select the member
7700 function from the set of overloaded member functions.
7702 So figure out the FUNCTION_TYPE that we want to match against. */
7705 /* If we can find a non-template function that matches, we can just
7706 use it. There's no point in generating template instantiations
7707 if we're just going to throw them out anyhow. But, of course, we
7708 can only do this when we don't *need* a template function. */
7711 {
7715 /* We're not looking for templates just yet. */
7719 /* We're looking for a non-static member, and this isn't
7720 one, or vice versa. */
7723 /* In C++17 we need the noexcept-qualifier to compare types. */
7728 /* See if there's a match. */
7733 }
7735 /* Now, if we've already got a match (or matches), there's no need
7736 to proceed to the template functions. But, if we don't have a
7737 match we need to look at them, too. */
7739 {
7740 tree target_arg_types;
7741 tree target_ret_type;
7744 tree arg;
7758 {
7760 tree instantiation;
7761 tree targs;
7764 /* We're only looking for templates. */
7769 /* We're not looking for a non-static member, and this is
7770 one, or vice versa. */
7775 /* If the template has a deduced return type, don't expose it to
7776 template argument deduction. */
7780 /* Try to do argument deduction. */
7787 /* Instantiation failed. */
7790 /* Constraints must be satisfied. This is done before
7791 return type deduction since that instantiates the
7792 function. */
7796 /* And now force instantiation to do return type deduction. */
7798 {
7804 }
7806 /* In C++17 we need the noexcept-qualifier to compare types. */
7810 /* See if there's a match. */
7815 }
7817 /* Now, remove all but the most specialized of the matches. */
7819 {
7824 NULL_TREE,
7825 NULL_TREE);
7826 }
7827 }
7829 /* Now we should have exactly one function in MATCHES. */
7831 {
7832 /* There were *no* matches. */
7834 {
7839 }
7841 }
7843 {
7844 /* There were too many matches. First check if they're all
7845 the same function. */
7850 /* For multi-versioned functions, more than one match is just fine and
7851 decls_match will return false as they are different. */
7859 {
7861 {
7865 /* Since print_candidates expects the functions in the
7866 TREE_VALUE slot, we flip them here. */
7871 }
7874 }
7875 }
7877 /* Good, exactly one match. Now, convert it to the correct type. */
7882 {
7890 {
7893 }
7894 }
7896 /* If a pointer to a function that is multi-versioned is requested, the
7897 pointer to the dispatcher function is returned instead. This works
7898 well because indirectly calling the function will dispatch the right
7899 function version at run-time. */
7901 {
7905 /* Mark all the versions corresponding to the dispatcher as used. */
7908 }
7910 /* If we're doing overload resolution purely for the purpose of
7911 determining conversion sequences, we should not consider the
7912 function used. If this conversion sequence is selected, the
7913 function will be marked as used at this point. */
7915 {
7916 /* Make =delete work with SFINAE. */
7921 }
7923 /* We could not check access to member functions when this
7924 expression was originally created since we did not know at that
7925 time to which function the expression referred. */
7927 {
7930 }
7934 else
7935 {
7936 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
7937 will mark the function as addressed, but here we must do it
7938 explicitly. */
7942 }
7943 }
7945 /* This function will instantiate the type of the expression given in
7946 RHS to match the type of LHSTYPE. If errors exist, then return
7947 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
7948 we complain on errors. If we are not complaining, never modify rhs,
7949 as overload resolution wants to try many possible instantiations, in
7950 the hope that at least one will work.
7952 For non-recursive calls, LHSTYPE should be a function, pointer to
7953 function, or a pointer to member function. */
7955 tree
7957 {
7964 {
7968 }
7971 {
7980 /* Microsoft allows `A::f' to be resolved to a
7981 pointer-to-member. */
7982 ;
7983 else
7984 {
7989 }
7990 }
7993 {
7996 }
7998 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
7999 deduce any type information. */
8001 {
8005 }
8007 /* If we instantiate a template, and it is a A ?: C expression
8008 with omitted B, look through the SAVE_EXPR. */
8012 /* There are only a few kinds of expressions that may have a type
8013 dependent on overload resolution. */
8019 /* This should really only be used when attempting to distinguish
8020 what sort of a pointer to function we have. For now, any
8021 arithmetic operation which is not supported on pointers
8022 is rejected as an error. */
8025 {
8027 {
8033 /* Do not lose object's side effects. */
8037 }
8044 /* This can happen if we are forming a pointer-to-member for a
8045 member template. */
8048 /* Fall through. */
8051 {
8055 return
8059 }
8063 return
8067 access_path);
8070 {
8075 }
8082 }
8084 }
8085 \f
8086 /* Return the name of the virtual function pointer field
8087 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8088 this may have to look back through base types to find the
8089 ultimate field name. (For single inheritance, these could
8090 all be the same name. Who knows for multiple inheritance). */
8092 static tree
8094 {
8100 {
8106 }
8114 }
8116 void
8118 {
8125 {
8130 }
8131 }
8133 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8134 according to [class]:
8135 The class-name is also inserted
8136 into the scope of the class itself. For purposes of access checking,
8137 the inserted class name is treated as if it were a public member name. */
8139 void
8141 {
8158 }
8160 /* Returns 1 if TYPE contains only padding bytes. */
8162 int
8164 {
8172 }
8174 /* Returns true if TYPE contains no actual data, just various
8175 possible combinations of empty classes and possibly a vptr. */
8177 bool
8179 {
8181 {
8182 tree field;
8183 tree binfo;
8184 tree base_binfo;
8187 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8188 out, but we'd like to be able to check this before then. */
8199 /* An unnamed bit-field is not a data member. */
8204 }
8209 }
8211 /* Note that NAME was looked up while the current class was being
8212 defined and that the result of that lookup was DECL. */
8214 void
8216 {
8217 splay_tree names_used;
8219 /* If we're not defining a class, there's nothing to do. */
8225 /* If there's already a binding for this NAME, then we don't have
8226 anything to worry about. */
8239 }
8241 /* Note that NAME was declared (as DECL) in the current class. Check
8242 to see that the declaration is valid. */
8244 void
8246 {
8247 splay_tree names_used;
8248 splay_tree_node n;
8250 /* Look to see if we ever used this name. */
8251 names_used
8255 /* The C language allows members to be declared with a type of the same
8256 name, and the C++ standard says this diagnostic is not required. So
8257 allow it in extern "C" blocks unless predantic is specified.
8258 Allow it in all cases if -ms-extensions is specified. */
8264 {
8265 /* [basic.scope.class]
8267 A name N used in a class S shall refer to the same declaration
8268 in its context and when re-evaluated in the completed scope of
8269 S. */
8274 }
8275 }
8277 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8278 Secondary vtables are merged with primary vtables; this function
8279 will return the VAR_DECL for the primary vtable. */
8281 tree
8283 {
8284 tree decl;
8288 {
8291 }
8295 }
8298 /* Returns the binfo for the primary base of BINFO. If the resulting
8299 BINFO is a virtual base, and it is inherited elsewhere in the
8300 hierarchy, then the returned binfo might not be the primary base of
8301 BINFO in the complete object. Check BINFO_PRIMARY_P or
8302 BINFO_LOST_PRIMARY_P to be sure. */
8304 static tree
8306 {
8307 tree primary_base;
8314 }
8316 /* As above, but iterate until we reach the binfo that actually provides the
8317 vptr for BINFO. */
8319 static tree
8321 {
8325 {
8330 }
8332 }
8334 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8335 type. Note that the virtual inheritance might be above or below BINFO in
8336 the hierarchy. */
8338 bool
8340 {
8344 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8345 a morally virtual base. */
8348 }
8350 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8352 static int
8354 {
8358 }
8360 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8361 INDENT should be zero when called from the top level; it is
8362 incremented recursively. IGO indicates the next expected BINFO in
8363 inheritance graph ordering. */
8365 static tree
8367 dump_flags_t flags,
8368 tree binfo,
8369 tree igo,
8371 {
8373 tree base_binfo;
8381 {
8384 }
8399 {
8403 TFF_PLAIN_IDENTIFIER),
8405 }
8407 {
8410 }
8415 {
8419 {
8423 TFF_PLAIN_IDENTIFIER));
8424 }
8426 {
8430 TFF_PLAIN_IDENTIFIER));
8431 }
8433 {
8437 TFF_PLAIN_IDENTIFIER));
8438 }
8440 {
8444 TFF_PLAIN_IDENTIFIER));
8445 }
8449 }
8455 }
8457 /* Dump the BINFO hierarchy for T. */
8459 static void
8461 {
8473 }
8475 /* Debug interface to hierarchy dumping. */
8477 void
8479 {
8481 }
8483 static void
8485 {
8486 dump_flags_t flags;
8488 {
8491 }
8492 }
8494 static void
8496 {
8497 tree value;
8499 HOST_WIDE_INT elt;
8507 TFF_PLAIN_IDENTIFIER));
8514 }
8516 static void
8518 {
8519 dump_flags_t flags;
8526 {
8533 {
8538 }
8542 }
8545 }
8547 static void
8549 {
8550 dump_flags_t flags;
8557 {
8562 }
8565 }
8567 /* Dump a function or thunk and its thunkees. */
8569 static void
8571 {
8574 tree thunks;
8582 {
8592 else
8598 }
8602 }
8604 /* Dump the thunks for FN. */
8606 void
8608 {
8610 }
8612 /* Virtual function table initialization. */
8614 /* Create all the necessary vtables for T and its base classes. */
8616 static void
8618 {
8619 tree vbase;
8623 /* We lay out the primary and secondary vtables in one contiguous
8624 vtable. The primary vtable is first, followed by the non-virtual
8625 secondary vtables in inheritance graph order. */
8629 /* Then come the virtual bases, also in inheritance graph order. */
8631 {
8635 }
8639 }
8641 /* Initialize the vtable for BINFO with the INITS. */
8643 static void
8645 {
8646 tree decl;
8652 }
8654 /* Build the VTT (virtual table table) for T.
8655 A class requires a VTT if it has virtual bases.
8657 This holds
8658 1 - primary virtual pointer for complete object T
8659 2 - secondary VTTs for each direct non-virtual base of T which requires a
8660 VTT
8661 3 - secondary virtual pointers for each direct or indirect base of T which
8662 has virtual bases or is reachable via a virtual path from T.
8663 4 - secondary VTTs for each direct or indirect virtual base of T.
8665 Secondary VTTs look like complete object VTTs without part 4. */
8667 static void
8669 {
8670 tree type;
8671 tree vtt;
8672 tree index;
8675 /* Build up the initializers for the VTT. */
8680 /* If we didn't need a VTT, we're done. */
8684 /* Figure out the type of the VTT. */
8688 /* Now, build the VTT object itself. */
8691 /* Add the VTT to the vtables list. */
8696 }
8698 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8699 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8700 and CHAIN the vtable pointer for this binfo after construction is
8701 complete. VALUE can also be another BINFO, in which case we recurse. */
8703 static tree
8705 {
8706 tree vt;
8709 {
8715 else
8717 }
8720 }
8722 /* Data for secondary VTT initialization. */
8723 struct secondary_vptr_vtt_init_data
8724 {
8725 /* Is this the primary VTT? */
8728 /* Current index into the VTT. */
8729 tree index;
8731 /* Vector of initializers built up. */
8734 /* The type being constructed by this secondary VTT. */
8735 tree type_being_constructed;
8736 };
8738 /* Recursively build the VTT-initializer for BINFO (which is in the
8739 hierarchy dominated by T). INITS points to the end of the initializer
8740 list to date. INDEX is the VTT index where the next element will be
8741 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8742 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8743 for virtual bases of T. When it is not so, we build the constructor
8744 vtables for the BINFO-in-T variant. */
8746 static void
8749 {
8751 tree b;
8752 tree init;
8753 secondary_vptr_vtt_init_data data;
8756 /* We only need VTTs for subobjects with virtual bases. */
8760 /* We need to use a construction vtable if this is not the primary
8761 VTT. */
8763 {
8766 /* Record the offset in the VTT where this sub-VTT can be found. */
8768 }
8770 /* Add the address of the primary vtable for the complete object. */
8774 {
8777 }
8780 /* Recursively add the secondary VTTs for non-virtual bases. */
8785 /* Add secondary virtual pointers for all subobjects of BINFO with
8786 either virtual bases or reachable along a virtual path, except
8787 subobjects that are non-virtual primary bases. */
8797 /* data.inits might have grown as we added secondary virtual pointers.
8798 Make sure our caller knows about the new vector. */
8802 /* Add the secondary VTTs for virtual bases in inheritance graph
8803 order. */
8805 {
8810 }
8811 else
8812 /* Remove the ctor vtables we created. */
8814 }
8816 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8817 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8819 static tree
8821 {
8824 /* We don't care about bases that don't have vtables. */
8828 /* We're only interested in proper subobjects of the type being
8829 constructed. */
8833 /* We're only interested in bases with virtual bases or reachable
8834 via a virtual path from the type being constructed. */
8839 /* We're not interested in non-virtual primary bases. */
8843 /* Record the index where this secondary vptr can be found. */
8845 {
8850 {
8851 /* It's a primary virtual base, and this is not a
8852 construction vtable. Find the base this is primary of in
8853 the inheritance graph, and use that base's vtable
8854 now. */
8857 }
8858 }
8860 /* Add the initializer for the secondary vptr itself. */
8863 /* Advance the vtt index. */
8868 }
8870 /* Called from build_vtt_inits via dfs_walk. After building
8871 constructor vtables and generating the sub-vtt from them, we need
8872 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8873 binfo of the base whose sub vtt was generated. */
8875 static tree
8877 {
8881 /* If this class has no vtable, none of its bases do. */
8885 /* This might be a primary base, so have no vtable in this
8886 hierarchy. */
8889 /* If we scribbled the construction vtable vptr into BINFO, clear it
8890 out now. */
8896 }
8898 /* Build the construction vtable group for BINFO which is in the
8899 hierarchy dominated by T. */
8901 static void
8903 {
8904 tree type;
8905 tree vtbl;
8906 tree id;
8907 tree vbase;
8910 /* See if we've already created this construction vtable group. */
8916 /* Build a version of VTBL (with the wrong type) for use in
8917 constructing the addresses of secondary vtables in the
8918 construction vtable group. */
8921 /* Don't export construction vtables from shared libraries. Even on
8922 targets that don't support hidden visibility, this tells
8923 can_refer_decl_in_current_unit_p not to assume that it's safe to
8924 access from a different compilation unit (bz 54314). */
8932 /* Add the vtables for each of our virtual bases using the vbase in T
8933 binfo. */
8935 vbase;
8937 {
8938 tree b;
8945 }
8947 /* Figure out the type of the construction vtable. */
8954 /* Initialize the construction vtable. */
8958 }
8960 /* Add the vtbl initializers for BINFO (and its bases other than
8961 non-virtual primaries) to the list of INITS. BINFO is in the
8962 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
8963 the constructor the vtbl inits should be accumulated for. (If this
8964 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
8965 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
8966 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
8967 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
8968 but are not necessarily the same in terms of layout. */
8970 static void
8972 tree orig_binfo,
8973 tree rtti_binfo,
8974 tree vtbl,
8975 tree t,
8977 {
8979 tree base_binfo;
8984 /* If it doesn't have a vptr, we don't do anything. */
8988 /* If we're building a construction vtable, we're not interested in
8989 subobjects that don't require construction vtables. */
8995 /* Build the initializers for the BINFO-in-T vtable. */
8998 /* Walk the BINFO and its bases. We walk in preorder so that as we
8999 initialize each vtable we can figure out at what offset the
9000 secondary vtable lies from the primary vtable. We can't use
9001 dfs_walk here because we need to iterate through bases of BINFO
9002 and RTTI_BINFO simultaneously. */
9004 {
9005 /* Skip virtual bases. */
9011 inits);
9012 }
9013 }
9015 /* Called from accumulate_vtbl_inits. Adds the initializers for the
9016 BINFO vtable to L. */
9018 static void
9020 tree orig_binfo,
9021 tree rtti_binfo,
9022 tree orig_vtbl,
9023 tree t,
9025 {
9032 {
9033 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9034 primary virtual base. If it is not the same primary in
9035 the hierarchy of T, we'll need to generate a ctor vtable
9036 for it, to place at its location in T. If it is the same
9037 primary, we still need a VTT entry for the vtable, but it
9038 should point to the ctor vtable for the base it is a
9039 primary for within the sub-hierarchy of RTTI_BINFO.
9041 There are three possible cases:
9043 1) We are in the same place.
9044 2) We are a primary base within a lost primary virtual base of
9045 RTTI_BINFO.
9046 3) We are primary to something not a base of RTTI_BINFO. */
9048 tree b;
9051 /* First, look through the bases we are primary to for RTTI_BINFO
9052 or a virtual base. */
9055 {
9060 }
9061 /* If we run out of primary links, keep looking down our
9062 inheritance chain; we might be an indirect primary. */
9066 found:
9068 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9069 base B and it is a base of RTTI_BINFO, this is case 2. In
9070 either case, we share our vtable with LAST, i.e. the
9071 derived-most base within B of which we are a primary. */
9074 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9075 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9076 binfo_ctor_vtable after everything's been set up. */
9079 /* Otherwise, this is case 3 and we get our own. */
9080 }
9087 {
9088 tree index;
9091 /* Add the initializer for this vtable. */
9095 /* Figure out the position to which the VPTR should point. */
9101 }
9104 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9105 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9106 straighten this out. */
9109 /* Throw away any unneeded intializers. */
9111 else
9112 /* For an ordinary vtable, set BINFO_VTABLE. */
9114 }
9119 /* Construct the initializer for BINFO's virtual function table. BINFO
9120 is part of the hierarchy dominated by T. If we're building a
9121 construction vtable, the ORIG_BINFO is the binfo we should use to
9122 find the actual function pointers to put in the vtable - but they
9123 can be overridden on the path to most-derived in the graph that
9124 ORIG_BINFO belongs. Otherwise,
9125 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9126 BINFO that should be indicated by the RTTI information in the
9127 vtable; it will be a base class of T, rather than T itself, if we
9128 are building a construction vtable.
9130 The value returned is a TREE_LIST suitable for wrapping in a
9131 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9132 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9133 number of non-function entries in the vtable.
9135 It might seem that this function should never be called with a
9136 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9137 base is always subsumed by a derived class vtable. However, when
9138 we are building construction vtables, we do build vtables for
9139 primary bases; we need these while the primary base is being
9140 constructed. */
9142 static void
9144 tree orig_binfo,
9145 tree t,
9146 tree rtti_binfo,
9149 {
9150 tree v;
9151 vtbl_init_data vid;
9153 tree vbinfo;
9157 /* Initialize VID. */
9165 /* The first vbase or vcall offset is at index -3 in the vtable. */
9168 /* Add entries to the vtable for RTTI. */
9171 /* Create an array for keeping track of the functions we've
9172 processed. When we see multiple functions with the same
9173 signature, we share the vcall offsets. */
9175 /* Add the vcall and vbase offset entries. */
9178 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9179 build_vbase_offset_vtbl_entries. */
9184 /* If the target requires padding between data entries, add that now. */
9186 {
9191 /* Move data entries into their new positions and add padding
9192 after the new positions. Iterate backwards so we don't
9193 overwrite entries that we would need to process later. */
9196 ix--)
9197 {
9205 {
9209 null_pointer_node);
9210 }
9211 }
9212 }
9217 /* The initializers for virtual functions were built up in reverse
9218 order. Straighten them out and add them to the running list in one
9219 step. */
9228 /* Go through all the ordinary virtual functions, building up
9229 initializers. */
9231 {
9232 tree delta;
9233 tree vcall_index;
9240 {
9244 {
9247 }
9249 }
9251 /* If the only definition of this function signature along our
9252 primary base chain is from a lost primary, this vtable slot will
9253 never be used, so just zero it out. This is important to avoid
9254 requiring extra thunks which cannot be generated with the function.
9256 We first check this in update_vtable_entry_for_fn, so we handle
9257 restored primary bases properly; we also need to do it here so we
9258 zero out unused slots in ctor vtables, rather than filling them
9259 with erroneous values (though harmless, apart from relocation
9260 costs). */
9265 {
9266 /* Pull the offset for `this', and the function to call, out of
9267 the list. */
9274 /* You can't call an abstract virtual function; it's abstract.
9275 So, we replace these functions with __pure_virtual. */
9277 {
9280 {
9282 abort_fndecl_addr
9286 }
9287 }
9288 /* Likewise for deleted virtuals. */
9290 {
9292 {
9296 dvirt_fn = push_library_fn
9300 }
9305 }
9306 else
9307 {
9309 {
9314 }
9315 /* Take the address of the function, considering it to be of an
9316 appropriate generic type. */
9320 /* Don't refer to a virtual destructor from a constructor
9321 vtable or a vtable for an abstract class, since destroying
9322 an object under construction is undefined behavior and we
9323 don't want it to be considered a candidate for speculative
9324 devirtualization. But do create the thunk for ABI
9325 compliance. */
9330 }
9331 }
9333 /* And add it to the chain of initializers. */
9335 {
9340 else
9342 {
9348 }
9349 }
9350 else
9352 }
9353 }
9355 /* Adds to vid->inits the initializers for the vbase and vcall
9356 offsets in BINFO, which is in the hierarchy dominated by T. */
9358 static void
9360 {
9361 tree b;
9363 /* If this is a derived class, we must first create entries
9364 corresponding to the primary base class. */
9369 /* Add the vbase entries for this base. */
9371 /* Add the vcall entries for this base. */
9373 }
9375 /* Returns the initializers for the vbase offset entries in the vtable
9376 for BINFO (which is part of the class hierarchy dominated by T), in
9377 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9378 where the next vbase offset will go. */
9380 static void
9382 {
9383 tree vbase;
9384 tree t;
9385 tree non_primary_binfo;
9387 /* If there are no virtual baseclasses, then there is nothing to
9388 do. */
9394 /* We might be a primary base class. Go up the inheritance hierarchy
9395 until we find the most derived class of which we are a primary base:
9396 it is the offset of that which we need to use. */
9399 {
9400 tree b;
9402 /* If we have reached a virtual base, then it must be a primary
9403 base (possibly multi-level) of vid->binfo, or we wouldn't
9404 have called build_vcall_and_vbase_vtbl_entries for it. But it
9405 might be a lost primary, so just skip down to vid->binfo. */
9407 {
9410 }
9416 }
9418 /* Go through the virtual bases, adding the offsets. */
9420 vbase;
9422 {
9423 tree b;
9424 tree delta;
9429 /* Find the instance of this virtual base in the complete
9430 object. */
9433 /* If we've already got an offset for this virtual base, we
9434 don't need another one. */
9439 /* Figure out where we can find this vbase offset. */
9448 /* The vbase offset had better be the same. */
9451 /* The next vbase will come at a more negative offset. */
9455 /* The initializer is the delta from BINFO to this virtual base.
9456 The vbase offsets go in reverse inheritance-graph order, and
9457 we are walking in inheritance graph order so these end up in
9458 the right order. */
9465 }
9466 }
9468 /* Adds the initializers for the vcall offset entries in the vtable
9469 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9470 to VID->INITS. */
9472 static void
9474 {
9475 /* We only need these entries if this base is a virtual base. We
9476 compute the indices -- but do not add to the vtable -- when
9477 building the main vtable for a class. */
9480 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9481 correspond to VID->DERIVED), we are building a primary
9482 construction virtual table. Since this is a primary
9483 virtual table, we do not need the vcall offsets for
9484 BINFO. */
9486 {
9487 /* We need a vcall offset for each of the virtual functions in this
9488 vtable. For example:
9490 class A { virtual void f (); };
9491 class B1 : virtual public A { virtual void f (); };
9492 class B2 : virtual public A { virtual void f (); };
9493 class C: public B1, public B2 { virtual void f (); };
9495 A C object has a primary base of B1, which has a primary base of A. A
9496 C also has a secondary base of B2, which no longer has a primary base
9497 of A. So the B2-in-C construction vtable needs a secondary vtable for
9498 A, which will adjust the A* to a B2* to call f. We have no way of
9499 knowing what (or even whether) this offset will be when we define B2,
9500 so we store this "vcall offset" in the A sub-vtable and look it up in
9501 a "virtual thunk" for B2::f.
9503 We need entries for all the functions in our primary vtable and
9504 in our non-virtual bases' secondary vtables. */
9506 /* If we are just computing the vcall indices -- but do not need
9507 the actual entries -- not that. */
9510 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9512 }
9513 }
9515 /* Build vcall offsets, starting with those for BINFO. */
9517 static void
9519 {
9521 tree primary_binfo;
9522 tree base_binfo;
9524 /* Don't walk into virtual bases -- except, of course, for the
9525 virtual base for which we are building vcall offsets. Any
9526 primary virtual base will have already had its offsets generated
9527 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9531 /* If BINFO has a primary base, process it first. */
9536 /* Add BINFO itself to the list. */
9539 /* Scan the non-primary bases of BINFO. */
9543 }
9545 /* Called from build_vcall_offset_vtbl_entries_r. */
9547 static void
9549 {
9550 /* Make entries for the rest of the virtuals. */
9551 tree orig_fn;
9553 /* The ABI requires that the methods be processed in declaration
9554 order. */
9556 orig_fn;
9560 }
9562 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9564 static void
9566 {
9568 tree vcall_offset;
9569 tree derived_entry;
9571 /* If there is already an entry for a function with the same
9572 signature as FN, then we do not need a second vcall offset.
9573 Check the list of functions already present in the derived
9574 class vtable. */
9576 {
9578 /* We only use one vcall offset for virtual destructors,
9579 even though there are two virtual table entries. */
9583 }
9585 /* If we are building these vcall offsets as part of building
9586 the vtable for the most derived class, remember the vcall
9587 offset. */
9589 {
9592 }
9594 /* The next vcall offset will be found at a more negative
9595 offset. */
9599 /* Keep track of this function. */
9603 {
9604 tree base;
9605 tree fn;
9607 /* Find the overriding function. */
9611 else
9612 {
9615 /* The vbase we're working on is a primary base of
9616 vid->binfo. But it might be a lost primary, so its
9617 BINFO_OFFSET might be wrong, so we just use the
9618 BINFO_OFFSET from vid->binfo. */
9624 vcall_offset);
9625 }
9626 /* Add the initializer to the vtable. */
9628 }
9629 }
9631 /* Return vtbl initializers for the RTTI entries corresponding to the
9632 BINFO's vtable. The RTTI entries should indicate the object given
9633 by VID->rtti_binfo. */
9635 static void
9637 {
9638 tree b;
9639 tree t;
9640 tree offset;
9641 tree decl;
9642 tree init;
9646 /* To find the complete object, we will first convert to our most
9647 primary base, and then add the offset in the vtbl to that value. */
9652 /* The second entry is the address of the typeinfo object. */
9655 else
9658 /* Convert the declaration to a type that can be stored in the
9659 vtable. */
9663 /* Add the offset-to-top entry. It comes earlier in the vtable than
9664 the typeinfo entry. Convert the offset to look like a
9665 function pointer, so that we can put it in the vtable. */
9668 }
9670 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9671 accessibility. */
9673 bool
9675 {
9678 }
9680 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9682 bool
9684 {
9688 }
9690 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9691 class between them, if any. */
9693 tree
9695 {
9707 {
9710 }
9714 }