| blob | e5f237cb0525cc55eaf0c9c1960b1acb29975c1d |
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 }
469 complain),
471 }
479 v_offset);
491 /* Negative fixed_type_p means this is a constructor or destructor;
492 virtual base layout is fixed in in-charge [cd]tors, but not in
493 base [cd]tors. */
494 offset = build_if_in_charge
496 v_offset);
497 else
499 }
507 {
512 }
513 else
516 indout:
518 {
522 }
524 out:
530 }
532 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
533 Perform a derived-to-base conversion by recursively building up a
534 sequence of COMPONENT_REFs to the appropriate base fields. */
536 static tree
538 {
541 tree field;
544 {
545 tree temp;
549 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
550 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
551 an lvalue in the front end; only _DECLs and _REFs are lvalues
552 in the back end. */
558 }
560 /* Recurse. */
565 /* Is this the base field created by build_base_field? */
569 /* If we're looking for a field in the most-derived class,
570 also check the field offset; we can have two base fields
571 of the same type if one is an indirect virtual base and one
572 is a direct non-virtual base. */
576 {
577 /* We don't use build_class_member_access_expr here, as that
578 has unnecessary checks, and more importantly results in
579 recursive calls to dfs_walk_once. */
585 /* Mark the expression const or volatile, as appropriate.
586 Even though we've dealt with the type above, we still have
587 to mark the expression itself. */
594 }
596 /* Didn't find the base field?!? */
598 }
600 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
601 type is a class type or a pointer to a class type. In the former
602 case, TYPE is also a class type; in the latter it is another
603 pointer type. If CHECK_ACCESS is true, an error message is emitted
604 if TYPE is inaccessible. If OBJECT has pointer type, the value is
605 assumed to be non-NULL. */
607 tree
609 tsubst_flags_t complain)
610 {
611 tree binfo;
612 tree object_type;
615 {
618 }
619 else
628 }
630 /* EXPR is an expression with unqualified class type. BASE is a base
631 binfo of that class type. Returns EXPR, converted to the BASE
632 type. This function assumes that EXPR is the most derived class;
633 therefore virtual bases can be found at their static offsets. */
635 tree
637 {
638 tree expr_type;
642 {
643 /* If this is a non-empty base, use a COMPONENT_REF. */
647 /* We use fold_build2 and fold_convert below to simplify the trees
648 provided to the optimizers. It is not safe to call these functions
649 when processing a template because they do not handle C++-specific
650 trees. */
658 }
661 }
663 \f
664 tree
666 {
670 /* Can happen in case of duplicate base types (c++/59082). */
674 /* First, convert to the requested type. */
679 /* Second, the requested type may not be the owner of its own vptr.
680 If not, convert to the base class that owns it. We cannot use
681 convert_to_base here, because VCONTEXT may appear more than once
682 in the inheritance hierarchy of TYPE, and thus direct conversion
683 between the types may be ambiguous. Following the path back up
684 one step at a time via primary bases avoids the problem. */
688 {
691 }
694 }
696 /* Given an object INSTANCE, return an expression which yields the
697 vtable element corresponding to INDEX. There are many special
698 cases for INSTANCE which we take care of here, mainly to avoid
699 creating extra tree nodes when we don't have to. */
701 static tree
703 {
704 tree aref;
707 /* Try to figure out what a reference refers to, and
708 access its virtual function table directly. */
716 {
721 }
730 }
732 tree
734 {
738 }
740 /* Given a stable object pointer INSTANCE_PTR, return an expression which
741 yields a function pointer corresponding to vtable element INDEX. */
743 tree
745 {
746 tree aref;
749 tf_warning_or_error),
750 idx);
752 /* When using function descriptors, the address of the
753 vtable entry is treated as a function pointer. */
758 /* Remember this as a method reference, for later devirtualization. */
762 }
764 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
765 for the given TYPE. */
767 static tree
769 {
771 }
773 /* DECL is an entity associated with TYPE, like a virtual table or an
774 implicitly generated constructor. Determine whether or not DECL
775 should have external or internal linkage at the object file
776 level. This routine does not deal with COMDAT linkage and other
777 similar complexities; it simply sets TREE_PUBLIC if it possible for
778 entities in other translation units to contain copies of DECL, in
779 the abstract. */
781 void
783 {
786 }
788 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
789 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
790 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
792 static tree
794 {
795 tree decl;
798 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
799 now to avoid confusion in mangle_decl. */
810 /* The vtable has not been defined -- yet. */
814 /* Mark the VAR_DECL node representing the vtable itself as a
815 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
816 is rather important that such things be ignored because any
817 effort to actually generate DWARF for them will run into
818 trouble when/if we encounter code like:
820 #pragma interface
821 struct S { virtual void member (); };
823 because the artificial declaration of the vtable itself (as
824 manufactured by the g++ front end) will say that the vtable is
825 a static member of `S' but only *after* the debug output for
826 the definition of `S' has already been output. This causes
827 grief because the DWARF entry for the definition of the vtable
828 will try to refer back to an earlier *declaration* of the
829 vtable as a static member of `S' and there won't be one. We
830 might be able to arrange to have the "vtable static member"
831 attached to the member list for `S' before the debug info for
832 `S' get written (which would solve the problem) but that would
833 require more intrusive changes to the g++ front end. */
837 }
839 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
840 or even complete. If this does not exist, create it. If COMPLETE is
841 nonzero, then complete the definition of it -- that will render it
842 impossible to actually build the vtable, but is useful to get at those
843 which are known to exist in the runtime. */
845 tree
847 {
848 tree decl;
857 {
860 }
863 }
865 /* Build the primary virtual function table for TYPE. If BINFO is
866 non-NULL, build the vtable starting with the initial approximation
867 that it is the same as the one which is the head of the association
868 list. Returns a nonzero value if a new vtable is actually
869 created. */
871 static int
873 {
874 tree decl;
875 tree virtuals;
880 {
882 /* We have already created a vtable for this base, so there's
883 no need to do it again. */
890 }
891 else
892 {
895 }
898 {
901 }
903 /* Initialize the association list for this type, based
904 on our first approximation. */
909 }
911 /* Give BINFO a new virtual function table which is initialized
912 with a skeleton-copy of its original initialization. The only
913 entry that changes is the `delta' entry, so we can really
914 share a lot of structure.
916 FOR_TYPE is the most derived type which caused this table to
917 be needed.
919 Returns nonzero if we haven't met BINFO before.
921 The order in which vtables are built (by calling this function) for
922 an object must remain the same, otherwise a binary incompatibility
923 can result. */
925 static int
927 {
929 /* We already created a vtable for this base. There's no need to
930 do it again. */
933 /* Remember that we've created a vtable for this BINFO, so that we
934 don't try to do so again. */
937 /* Make fresh virtual list, so we can smash it later. */
940 /* Secondary vtables are laid out as part of the same structure as
941 the primary vtable. */
944 }
946 /* Create a new vtable for BINFO which is the hierarchy dominated by
947 T. Return nonzero if we actually created a new vtable. */
949 static int
951 {
953 /* In this case, it is *type*'s vtable we are modifying. We start
954 with the approximation that its vtable is that of the
955 immediate base class. */
957 else
958 /* This is our very own copy of `basetype' to play with. Later,
959 we will fill in all the virtual functions that override the
960 virtual functions in these base classes which are not defined
961 by the current type. */
963 }
965 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
966 (which is in the hierarchy dominated by T) list FNDECL as its
967 BV_FN. DELTA is the required constant adjustment from the `this'
968 pointer where the vtable entry appears to the `this' required when
969 the function is actually called. */
971 static void
973 tree binfo,
974 tree fndecl,
975 tree delta,
977 {
978 tree v;
984 {
985 /* We need a new vtable for BINFO. */
987 {
988 /* If we really did make a new vtable, we also made a copy
989 of the BINFO_VIRTUALS list. Now, we have to find the
990 corresponding entry in that list. */
995 }
1000 }
1001 }
1003 \f
1004 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
1005 METHOD is being injected via a using_decl. Returns true if the
1006 method could be added to the method vec. */
1008 bool
1010 {
1016 {
1017 /* Make a new method vector. We start with 8 entries. */
1020 }
1022 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1033 /* See if we already have an entry with this name. */
1035 tree m;
1037 {
1040 {
1043 }
1046 }
1051 {
1052 /* For conversion operators, we prepend a dummy overload
1053 pointing at conv_op_marker. That function's DECL_NAME is
1054 conv_op_identifier, so we can use identifier equality to
1055 locate it. */
1057 {
1061 }
1062 else
1064 }
1067 /* Check to see if we've already got this method. */
1069 {
1071 tree fn_type;
1072 tree method_type;
1073 tree parms1;
1074 tree parms2;
1079 /* Two using-declarations can coexist, we'll complain about ambiguity in
1080 overload resolution. */
1082 /* Except handle inherited constructors specially. */
1086 /* [over.load] Member function declarations with the
1087 same name and the same parameter types cannot be
1088 overloaded if any of them is a static member
1089 function declaration.
1091 [over.load] Member function declarations with the same name and
1092 the same parameter-type-list as well as member function template
1093 declarations with the same name, the same parameter-type-list, and
1094 the same template parameter lists cannot be overloaded if any of
1095 them, but not all, have a ref-qualifier.
1097 [namespace.udecl] When a using-declaration brings names
1098 from a base class into a derived class scope, member
1099 functions in the derived class override and/or hide member
1100 functions with the same name and parameter types in a base
1101 class (rather than conflicting). */
1107 /* Compare the quals on the 'this' parm. Don't compare
1108 the whole types, as used functions are treated as
1109 coming from the using class in overload resolution. */
1112 /* Either both or neither need to be ref-qualified for
1113 differing quals to allow overloading. */
1120 /* For templates, the return type and template parameters
1121 must be identical. */
1134 /* Bring back parameters omitted from an inherited ctor. */
1145 {
1146 /* If these are versions of the same function, process and
1147 move on. */
1153 {
1155 {
1159 {
1161 {
1162 /* Inheriting the same constructor along different
1163 paths, combine them. */
1164 SET_DECL_INHERITED_CTOR
1167 /* And discard the new one. */
1169 }
1170 else
1171 /* Inherited ctors can coexist until overload
1172 resolution. */
1174 }
1180 basef);
1181 }
1182 /* Otherwise defer to the other function. */
1184 }
1187 /* Defer to the local function. */
1191 {
1192 /* Remove the inherited constructor. */
1195 }
1196 else
1197 {
1203 }
1204 }
1205 }
1207 /* A class should never have more than one destructor. */
1213 {
1215 /* Prepend the marker function. */
1218 }
1223 {
1226 /* We only expect to add few methods in the COMPLETE_P case, so
1227 just make room for one more method in that case. */
1230 else
1236 else
1238 }
1239 else
1240 /* Replace the current slot. */
1243 }
1245 /* Subroutines of finish_struct. */
1247 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1248 legit, otherwise return 0. */
1250 static int
1252 {
1253 tree elem;
1261 {
1263 {
1267 else
1270 }
1271 else
1272 {
1273 /* They're changing the access to the same thing they changed
1274 it to before. That's OK. */
1275 ;
1276 }
1277 }
1278 else
1279 {
1281 tf_warning_or_error);
1284 }
1286 }
1288 /* Return the access node for DECL's access in its enclosing class. */
1290 tree
1292 {
1296 }
1298 /* Process the USING_DECL, which is a member of T. */
1300 static void
1302 {
1307 tree old_value;
1312 tf_warning_or_error);
1314 {
1319 else
1321 }
1329 ;
1331 {
1333 /* It's OK to use functions from a base when there are functions with
1335 else
1336 {
1343 }
1344 }
1346 {
1353 }
1355 /* Make type T see field decl FDECL with access ACCESS. */
1358 {
1361 }
1362 else
1364 }
1365 \f
1366 /* Data structure for find_abi_tags_r, below. */
1368 struct abi_tag_data
1369 {
1373 };
1375 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1376 in the context of P. TAG can be either an identifier (the DECL_NAME of
1377 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1379 static void
1381 {
1383 {
1385 {
1386 /* We're collecting tags from template arguments or from
1387 the type of a variable or function return type. */
1390 /* Don't inherit this tag multiple times. */
1394 {
1395 /* Tags inherited from type template arguments are only used
1396 to avoid warnings. */
1399 }
1400 /* For functions and variables we want to warn, too. */
1401 }
1403 /* Otherwise we're diagnosing missing tags. */
1405 {
1410 }
1412 {
1416 }
1418 {
1423 }
1424 else
1425 {
1429 {
1433 }
1434 }
1435 }
1436 }
1438 /* Find all the ABI tags in the attribute list ATTR and either call
1439 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1441 static void
1443 {
1450 {
1455 else
1457 }
1458 }
1460 /* Find all the ABI tags on T and its enclosing scopes and either call
1461 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1463 static void
1465 {
1467 {
1468 tree attr;
1470 {
1473 }
1474 else
1475 {
1478 }
1480 }
1481 }
1483 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1484 types with ABI tags, add the corresponding identifiers to the VEC in
1485 *DATA and set IDENTIFIER_MARKED. */
1487 static tree
1489 {
1493 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1494 anyway, but let's make sure of it. */
1502 }
1504 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1505 IDENTIFIER_MARKED on its ABI tags. */
1507 static tree
1509 {
1513 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1514 anyway, but let's make sure of it. */
1522 }
1524 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1525 scopes. */
1527 static void
1529 {
1532 {
1535 {
1536 /* Template arguments are part of the signature. */
1539 {
1542 }
1543 }
1545 /* A function's parameter types are part of the signature, so
1546 we don't need to inherit any tags that are also in them. */
1551 }
1552 }
1554 /* Check that T has all the ABI tags that subobject SUBOB has, or
1555 warn if not. If T is a (variable or function) declaration, also
1556 return any missing tags, and add them to T if JUST_CHECKING is false. */
1558 static tree
1560 {
1568 /* No need to worry about things local to this TU. */
1584 {
1587 }
1588 else
1589 {
1593 else
1597 }
1602 }
1604 /* Check that DECL has all the ABI tags that are used in parts of its type
1605 that are not reflected in its mangled name. */
1607 void
1609 {
1616 }
1618 /* Return any ABI tags that are used in parts of the type of DECL
1619 that are not reflected in its mangled name. This function is only
1620 used in backward-compatible mangling for ABI <11. */
1622 tree
1624 {
1628 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1629 that we can use this function for setting need_abi_warning
1630 regardless of the current flag_abi_version. */
1633 else
1635 }
1637 void
1639 {
1649 {
1652 {
1656 }
1657 }
1659 // If we found some tags on our template arguments, add them to our
1660 // abi_tag attribute.
1662 {
1666 else
1670 }
1673 }
1675 /* Return true, iff class T has a non-virtual destructor that is
1676 accessible from outside the class heirarchy (i.e. is public, or
1677 there's a suitable friend. */
1679 static bool
1681 {
1684 /* An implicitly declared destructor is always public. And,
1685 if it were virtual, we would have created it by now. */
1700 }
1702 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1703 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1704 properties of the bases. */
1706 static void
1710 {
1714 tree base_binfo;
1715 tree binfo;
1725 {
1734 /* If any base class is non-literal, so is the derived class. */
1738 /* If the base class doesn't have copy constructors or
1739 assignment operators that take const references, then the
1740 derived class cannot have such a member automatically
1741 generated. */
1750 /* A virtual base does not effect nearly emptiness. */
1751 ;
1753 {
1755 /* And if there is more than one nearly empty base, then the
1756 derived class is not nearly empty either. */
1758 else
1759 /* Remember we've seen one. */
1761 }
1763 /* If the base class is not empty or nearly empty, then this
1764 class cannot be nearly empty. */
1767 /* A lot of properties from the bases also apply to the derived
1768 class. */
1785 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1788 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1794 /* A standard-layout class is a class that:
1795 ...
1796 * has no non-standard-layout base classes, */
1799 {
1800 tree basefield;
1801 /* ...has no base classes of the same type as the first non-static
1802 data member... */
1804 && (same_type_ignoring_top_level_qualifiers_p
1807 else
1808 /* ...either has no non-static data members in the most-derived
1809 class and at most one base class with non-static data
1810 members, or has no base classes with non-static data
1811 members */
1817 {
1820 else
1823 }
1824 }
1826 /* Don't bother collecting tm attributes if transactional memory
1827 support is not enabled. */
1829 {
1833 }
1836 }
1838 /* If one of the base classes had TM attributes, and the current class
1839 doesn't define its own, then the current class inherits one. */
1841 {
1844 }
1845 }
1847 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1848 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1849 that have had a nearly-empty virtual primary base stolen by some
1850 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1851 T. */
1853 static void
1855 {
1859 tree base_binfo;
1861 /* Determine the primary bases of our bases. */
1864 {
1867 /* See if we're the non-virtual primary of our inheritance
1868 chain. */
1870 {
1877 /* We are the primary binfo. */
1879 }
1880 /* Determine if we have a virtual primary base, and mark it so.
1881 */
1883 {
1887 /* Someone already claimed this base. */
1889 else
1890 {
1891 tree delta;
1896 /* A virtual binfo might have been copied from within
1897 another hierarchy. As we're about to use it as a
1898 primary base, make sure the offsets match. */
1906 }
1907 }
1908 }
1910 /* First look for a dynamic direct non-virtual base. */
1912 {
1916 {
1919 }
1920 }
1922 /* A "nearly-empty" virtual base class can be the primary base
1923 class, if no non-virtual polymorphic base can be found. Look for
1924 a nearly-empty virtual dynamic base that is not already a primary
1925 base of something in the hierarchy. If there is no such base,
1926 just pick the first nearly-empty virtual base. */
1932 {
1934 {
1935 /* Found one that is not primary. */
1938 }
1940 /* Remember the first candidate. */
1942 }
1944 found:
1945 /* If we've got a primary base, use it. */
1947 {
1952 /* We are stealing a primary base. */
1956 {
1957 tree delta;
1960 /* A virtual binfo might have been copied from within
1961 another hierarchy. As we're about to use it as a primary
1962 base, make sure the offsets match. */
1967 }
1974 }
1975 }
1977 /* Update the variant types of T. */
1979 void
1981 {
1982 tree variants;
1988 variants;
1990 {
1991 /* These fields are in the _TYPE part of the node, not in
1992 the TYPE_LANG_SPECIFIC component, so they are not shared. */
2002 /* Copy whatever these are holding today. */
2005 }
2006 }
2008 /* KLASS is a class that we're applying may_alias to after the body is
2009 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
2010 canonical type(s) will be implicitly updated. */
2012 static void
2014 {
2023 }
2025 /* Early variant fixups: we apply attributes at the beginning of the class
2026 definition, and we need to fix up any variants that have already been
2027 made via elaborated-type-specifier so that check_qualified_type works. */
2029 void
2031 {
2032 tree variants;
2046 variants;
2048 {
2049 /* These are the two fields that check_qualified_type looks at and
2050 are affected by attributes. */
2055 else
2060 }
2061 }
2062 \f
2063 /* Set memoizing fields and bits of T (and its variants) for later
2064 use. */
2066 static void
2068 {
2069 /* Fix up variants (if any). */
2073 /* For a class w/o baseclasses, 'finish_struct' has set
2074 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2075 Similarly for a class whose base classes do not have vtables.
2076 When neither of these is true, we might have removed abstract
2077 virtuals (by providing a definition), added some (by declaring
2078 new ones), or redeclared ones from a base class. We need to
2079 recalculate what's really an abstract virtual at this point (by
2080 looking in the vtables). */
2083 /* If this type has a copy constructor or a destructor, force its
2084 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2085 nonzero. This will cause it to be passed by invisible reference
2086 and prevent it from being returned in a register. */
2089 {
2090 tree variants;
2093 {
2096 }
2097 }
2098 }
2100 /* Issue warnings about T having private constructors, but no friends,
2101 and so forth.
2103 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2104 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2105 non-private static member functions. */
2107 static void
2109 {
2114 /* If the class has friends, those entities might create and
2115 access instances, so we should not warn. */
2118 /* We will have warned when the template was declared; there's
2119 no need to warn on every instantiation. */
2121 /* There's no reason to even consider warning about this
2122 class. */
2125 /* We only issue one warning, if more than one applies, because
2126 otherwise, on code like:
2128 class A {
2129 // Oops - forgot `public:'
2130 A();
2131 A(const A&);
2132 ~A();
2133 };
2135 we warn several times about essentially the same problem. */
2137 /* Check to see if all (non-constructor, non-destructor) member
2138 functions are private. (Since there are no friends or
2139 non-private statics, we can't ever call any of the private member
2140 functions.) */
2145 /* We're not interested in compiler-generated methods; they don't
2148 {
2150 /* A non-private static member function is just like a
2151 friend; it can create and invoke private member
2152 functions, and be accessed without a class
2153 instance. */
2157 /* Keep searching for a static member function. */
2158 }
2163 {
2164 /* There are no non-private methods, and there's at least one
2165 private member function that isn't a constructor or
2166 destructor. (If all the private members are
2167 constructors/destructors we want to use the code below that
2168 issues error messages specifically referring to
2169 constructors/destructors.) */
2175 {
2178 }
2180 {
2184 }
2185 }
2187 /* Even if some of the member functions are non-private, the class
2188 won't be useful for much if all the constructors or destructors
2189 are private: such an object can never be created or destroyed. */
2192 {
2195 t);
2197 }
2199 /* Warn about classes that have private constructors and no friends. */
2201 /* Implicitly generated constructors are always public. */
2203 {
2207 /* If a non-template class does not define a copy
2208 constructor, one is defined for it, enabling it to avoid
2209 this warning. For a template class, this does not
2210 happen, and so we would normally get a warning on:
2212 template <class T> class C { private: C(); };
2214 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2215 complete non-template or fully instantiated classes have this
2216 flag set. */
2219 else
2225 /* Ideally, we wouldn't count any constructor that takes
2226 an argument of the class type as a parameter, because
2227 such things cannot be used to construct an instance of
2228 the class unless you already have one. */
2230 else
2234 {
2237 t);
2243 }
2244 }
2245 }
2247 /* Make BINFO's vtable have N entries, including RTTI entries,
2248 vbase and vcall offsets, etc. Set its type and call the back end
2249 to lay it out. */
2251 static void
2253 {
2254 tree atype;
2255 tree vtable;
2260 /* We may have to grow the vtable. */
2263 {
2267 }
2268 }
2270 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2271 have the same signature. */
2273 int
2275 {
2276 /* One destructor overrides another if they are the same kind of
2277 destructor. */
2281 /* But a non-destructor never overrides a destructor, nor vice
2282 versa, nor do different kinds of destructors override
2283 one-another. For example, a complete object destructor does not
2284 override a deleting destructor. */
2293 {
2301 }
2303 }
2305 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2306 subobject. */
2308 static bool
2310 {
2311 tree probe;
2314 {
2318 /* If we meet a virtual base, we can't follow the inheritance
2319 any more. See if the complete type of DERIVED contains
2320 such a virtual base. */
2323 }
2325 }
2328 /* The function for which we are trying to find a final overrider. */
2329 tree fn;
2330 /* The base class in which the function was declared. */
2331 tree declaring_base;
2332 /* The candidate overriders. */
2333 tree candidates;
2334 /* Path to most derived. */
2336 };
2338 /* Add the overrider along the current path to FFOD->CANDIDATES.
2339 Returns true if an overrider was found; false otherwise. */
2341 static bool
2345 {
2346 tree method;
2348 /* If BINFO is not the most derived type, try a more derived class.
2349 A definition there will overrider a definition here. */
2351 {
2352 depth--;
2356 }
2360 {
2363 /* Remove any candidates overridden by this new function. */
2365 {
2366 /* If *CANDIDATE overrides METHOD, then METHOD
2367 cannot override anything else on the list. */
2370 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2373 else
2375 }
2377 /* Add the new function. */
2380 }
2383 }
2385 /* Called from find_final_overrider via dfs_walk. */
2387 static tree
2389 {
2397 }
2399 static tree
2401 {
2406 }
2408 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2409 FN and whose TREE_VALUE is the binfo for the base where the
2410 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2411 DERIVED) is the base object in which FN is declared. */
2413 static tree
2415 {
2416 find_final_overrider_data ffod;
2418 /* Getting this right is a little tricky. This is valid:
2420 struct S { virtual void f (); };
2421 struct T { virtual void f (); };
2422 struct U : public S, public T { };
2424 even though calling `f' in `U' is ambiguous. But,
2426 struct R { virtual void f(); };
2427 struct S : virtual public R { virtual void f (); };
2428 struct T : virtual public R { virtual void f (); };
2429 struct U : public S, public T { };
2431 is not -- there's no way to decide whether to put `S::f' or
2432 `T::f' in the vtable for `R'.
2434 The solution is to look at all paths to BINFO. If we find
2435 different overriders along any two, then there is a problem. */
2439 /* Determine the depth of the hierarchy. */
2450 /* If there was no winner, issue an error message. */
2455 }
2457 /* Return the index of the vcall offset for FN when TYPE is used as a
2458 virtual base. */
2460 static tree
2462 {
2464 tree_pair_p p;
2472 /* There should always be an appropriate index. */
2474 }
2476 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2477 dominated by T. FN is the old function; VIRTUALS points to the
2478 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2479 of that entry in the list. */
2481 static void
2484 {
2485 tree b;
2486 tree overrider;
2487 tree delta;
2488 tree virtual_base;
2489 tree first_defn;
2495 /* Find the nearest primary base (possibly binfo itself) which defines
2496 this function; this is the class the caller will convert to when
2497 calling FN through BINFO. */
2499 {
2504 /* The nearest definition is from a lost primary. */
2507 }
2510 /* Find the final overrider. */
2513 {
2516 }
2519 /* Check for adjusting covariant return types. */
2527 /* If the overrider is invalid, don't even try. */
2529 {
2530 /* If FN is a covariant thunk, we must figure out the adjustment
2531 to the final base FN was converting to. As OVERRIDER_TARGET might
2532 also be converting to the return type of FN, we have to
2533 combine the two conversions here. */
2540 {
2544 }
2545 else
2549 /* Find the equivalent binfo within the return type of the
2550 overriding function. We will want the vbase offset from
2551 there. */
2553 over_return);
2556 {
2557 /* There was no existing virtual thunk (which takes
2558 precedence). So find the binfo of the base function's
2559 return type within the overriding function's return type.
2560 Fortunately we know the covariancy is valid (it
2561 has already been checked), so we can just iterate along
2562 the binfos, which have been chained in inheritance graph
2563 order. Of course it is lame that we have to repeat the
2564 search here anyway -- we should really be caching pieces
2565 of the vtable and avoiding this repeated work. */
2568 /* Find the base binfo within the overriding function's
2569 return type. We will always find a thunk_binfo, except
2570 when the covariancy is invalid (which we will have
2571 already diagnosed). */
2574 thunk_binfo;
2580 /* See if virtual inheritance is involved. */
2582 virtual_offset;
2589 {
2593 {
2594 /* We convert via virtual base. Adjust the fixed
2595 offset to be from there. */
2596 offset =
2600 }
2602 /* There was an existing fixed offset, this must be
2603 from the base just converted to, and the base the
2604 FN was thunking to. */
2606 else
2608 }
2609 }
2612 /* Replace the overriding function with a covariant thunk. We
2613 will emit the overriding function in its own slot as
2614 well. */
2617 }
2618 else
2622 /* If we need a covariant thunk, then we may need to adjust first_defn.
2623 The ABI specifies that the thunks emitted with a function are
2624 determined by which bases the function overrides, so we need to be
2625 sure that we're using a thunk for some overridden base; even if we
2626 know that the necessary this adjustment is zero, there may not be an
2627 appropriate zero-this-adjustment thunk for us to use since thunks for
2628 overriding virtual bases always use the vcall offset.
2630 Furthermore, just choosing any base that overrides this function isn't
2631 quite right, as this slot won't be used for calls through a type that
2632 puts a covariant thunk here. Calling the function through such a type
2633 will use a different slot, and that slot is the one that determines
2634 the thunk emitted for that base.
2636 So, keep looking until we find the base that we're really overriding
2637 in this slot: the nearest primary base that doesn't use a covariant
2638 thunk in this slot. */
2640 {
2642 /* We already know that the overrider needs a covariant thunk. */
2645 {
2652 }
2654 }
2656 /* Assume that we will produce a thunk that convert all the way to
2657 the final overrider, and not to an intermediate virtual base. */
2660 /* See if we can convert to an intermediate virtual base first, and then
2661 use the vcall offset located there to finish the conversion. */
2663 {
2664 /* If we find the final overrider, then we can stop
2665 walking. */
2670 /* If we find a virtual base, and we haven't yet found the
2671 overrider, then there is a virtual base between the
2672 declaring base (first_defn) and the final overrider. */
2674 {
2677 }
2678 }
2680 /* Compute the constant adjustment to the `this' pointer. The
2681 `this' pointer, when this function is called, will point at BINFO
2682 (or one of its primary bases, which are at the same offset). */
2684 /* The `this' pointer needs to be adjusted from the declaration to
2685 the nearest virtual base. */
2690 /* If the nearest definition is in a lost primary, we don't need an
2691 entry in our vtable. Except possibly in a constructor vtable,
2692 if we happen to get our primary back. In that case, the offset
2693 will be zero, as it will be a primary base. */
2695 else
2696 /* The `this' pointer needs to be adjusted from pointing to
2697 BINFO to pointing at the base where the final overrider
2698 appears. */
2709 else
2713 }
2715 /* Called from modify_all_vtables via dfs_walk. */
2717 static tree
2719 {
2721 tree virtuals;
2722 tree old_virtuals;
2726 /* A base without a vtable needs no modification, and its bases
2727 are uninteresting. */
2732 /* Don't do the primary vtable, if it's new. */
2736 /* There's no need to modify the vtable for a non-virtual primary
2737 base; we're not going to use that vtable anyhow. We do still
2738 need to do this for virtual primary bases, as they could become
2739 non-primary in a construction vtable. */
2744 /* Now, go through each of the virtual functions in the virtual
2745 function table for BINFO. Find the final overrider, and update
2746 the BINFO_VIRTUALS list appropriately. */
2749 virtuals;
2753 binfo,
2758 }
2760 /* Update all of the primary and secondary vtables for T. Create new
2761 vtables as required, and initialize their RTTI information. Each
2762 of the functions in VIRTUALS is declared in T and may override a
2763 virtual function from a base class; find and modify the appropriate
2764 entries to point to the overriding functions. Returns a list, in
2765 declaration order, of the virtual functions that are declared in T,
2766 but do not appear in the primary base class vtable, and which
2767 should therefore be appended to the end of the vtable for T. */
2769 static tree
2771 {
2775 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2779 /* Update all of the vtables. */
2782 /* Add virtual functions not already in our primary vtable. These
2783 will be both those introduced by this class, and those overridden
2784 from secondary bases. It does not include virtuals merely
2785 inherited from secondary bases. */
2787 {
2792 {
2793 /* We don't need to adjust the `this' pointer when
2794 calling this function. */
2798 /* This is a function not already in our vtable. Keep it. */
2800 }
2801 else
2802 /* We've already got an entry for this function. Skip it. */
2804 }
2807 }
2809 /* Get the base virtual function declarations in T that have the
2810 indicated NAME. */
2812 static void
2814 {
2817 /* Find virtual functions in T with the indicated NAME. */
2819 {
2823 {
2826 }
2827 }
2834 {
2837 }
2838 }
2840 /* If this declaration supersedes the declaration of
2841 a method declared virtual in the base class, then
2842 mark this field as being virtual as well. */
2844 void
2846 {
2849 /* In [temp.mem] we have:
2851 A specialization of a member function template does not
2852 override a virtual function from a base class. */
2859 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2860 the error_mark_node so that we know it is an overriding
2861 function. */
2862 {
2869 }
2872 {
2878 }
2883 }
2885 /* Warn about hidden virtual functions that are not overridden in t.
2886 We know that constructors and destructors don't apply. */
2888 static void
2890 {
2892 tree fns;
2894 /* We go through each separately named virtual function. */
2896 {
2899 tree base_binfo;
2900 tree binfo;
2903 /* Iterate through all of the base classes looking for possibly
2904 hidden functions. */
2907 {
2910 }
2912 /* If there are no functions to hide, continue. */
2916 /* Remove any overridden functions. */
2918 {
2922 {
2923 /* If the method from the base class has the same
2924 signature as the method from the derived class, it
2925 has been overridden. */
2930 }
2931 }
2933 /* Now give a warning for all base functions without overriders,
2934 as they are hidden. */
2936 tree base_fndecl;
2939 {
2940 /* Here we know it is a hider, and no overrider exists. */
2942 OPT_Woverloaded_virtual,
2946 }
2947 }
2948 }
2950 /* Recursive helper for finish_struct_anon. */
2952 static void
2954 {
2958 {
2959 /* We're generally only interested in entities the user
2960 declared, but we also find nested classes by noticing
2961 the TYPE_DECL that we create implicitly. You're
2962 allowed to put one anonymous union inside another,
2963 though, so we explicitly tolerate that. We use
2964 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2965 we also allow unnamed types used for defining fields. */
2972 {
2973 /* We already complained about static data members in
2974 finish_static_data_member_decl. */
2976 {
2979 "%q#D invalid; an anonymous union can "
2981 else
2983 "%q#D invalid; an anonymous struct can "
2985 }
2987 }
2990 {
2992 {
2996 else
2999 }
3001 {
3005 else
3008 }
3009 }
3014 /* Recurse into the anonymous aggregates to handle correctly
3015 access control (c++/24926):
3017 class A {
3018 union {
3019 union {
3020 int i;
3021 };
3022 };
3023 };
3025 int j=A().i; */
3029 }
3030 }
3032 /* Check for things that are invalid. There are probably plenty of other
3033 things we should check for also. */
3035 static void
3037 {
3039 {
3048 }
3049 }
3051 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
3052 will be used later during class template instantiation.
3053 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
3054 a non-static member data (FIELD_DECL), a member function
3055 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
3056 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
3057 When FRIEND_P is nonzero, T is either a friend class
3058 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
3059 (FUNCTION_DECL, TEMPLATE_DECL). */
3061 void
3063 {
3064 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
3069 }
3071 /* This function is called from declare_virt_assop_and_dtor via
3072 dfs_walk_all.
3074 DATA is a type that direcly or indirectly inherits the base
3075 represented by BINFO. If BINFO contains a virtual assignment [copy
3076 assignment or move assigment] operator or a virtual constructor,
3077 declare that function in DATA if it hasn't been already declared. */
3079 static tree
3081 {
3089 /* A base without a vtable needs no modification, and its bases
3090 are uninteresting. */
3094 /* If this is a primary base, then we have already looked at the
3095 virtual functions of its vtable. */
3099 {
3103 {
3108 }
3112 }
3115 }
3117 /* If the class type T has a direct or indirect base that contains a
3118 virtual assignment operator or a virtual destructor, declare that
3119 function in T if it hasn't been already declared. */
3121 static void
3123 {
3131 dfs_declare_virt_assop_and_dtor,
3133 }
3135 /* Declare the inheriting constructor for class T inherited from base
3136 constructor CTOR with the parameter array PARMS of size NPARMS. */
3138 static void
3140 {
3143 /* We don't declare an inheriting ctor that would be a default,
3144 copy or move ctor for derived or base. */
3149 {
3153 }
3162 {
3165 }
3166 }
3168 /* Declare all the inheriting constructors for class T inherited from base
3169 constructor CTOR. */
3171 static void
3173 {
3177 {
3183 }
3188 {
3192 }
3195 {
3199 }
3200 }
3202 /* Create default constructors, assignment operators, and so forth for
3203 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3204 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3205 the class cannot have a default constructor, copy constructor
3206 taking a const reference argument, or an assignment operator taking
3207 a const reference, respectively. */
3209 static void
3213 {
3214 /* Destructor. */
3216 /* In general, we create destructors lazily. */
3225 /* [class.ctor]
3227 If there is no user-declared constructor for a class, a default
3228 constructor is implicitly declared. */
3230 {
3235 /* Don't force the declaration to get a hard answer; if the
3236 definition would have made the class non-literal, it will still be
3237 non-literal because of the base or member in question, and that
3238 gives a better diagnostic. */
3240 }
3242 /* [class.ctor]
3244 If a class definition does not explicitly declare a copy
3245 constructor, one is declared implicitly. */
3247 {
3253 }
3255 /* If there is no assignment operator, one will be created if and
3256 when it is needed. For now, just record whether or not the type
3257 of the parameter to the assignment operator will be a const or
3258 non-const reference. */
3260 {
3266 }
3268 /* We can't be lazy about declaring functions that might override
3269 a virtual function from a base class. */
3273 {
3277 {
3278 /* declare, then remove the decl */
3286 }
3287 else
3289 }
3290 }
3292 /* FIELD is a bit-field. We are finishing the processing for its
3293 enclosing type. Issue any appropriate messages and set appropriate
3294 flags. Returns false if an error has been diagnosed. */
3296 static bool
3298 {
3300 tree w;
3302 /* Extract the declared width of the bitfield, which has been
3303 temporarily stashed in DECL_INITIAL. */
3306 /* Remove the bit-field width indicator so that the rest of the
3307 compiler does not treat that value as an initializer. */
3310 /* Detect invalid bit-field type. */
3312 {
3315 }
3316 else
3317 {
3319 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3322 /* detect invalid field size. */
3328 {
3331 }
3333 {
3336 }
3338 {
3341 }
3356 }
3359 {
3363 }
3364 else
3365 {
3366 /* Non-bit-fields are aligned for their type. */
3370 }
3371 }
3373 /* FIELD is a non bit-field. We are finishing the processing for its
3374 enclosing type T. Issue any appropriate messages and set appropriate
3375 flags. */
3377 static bool
3379 tree t,
3382 {
3386 /* In C++98 an anonymous union cannot contain any fields which would change
3387 the settings of CANT_HAVE_CONST_CTOR and friends. */
3389 ;
3390 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3391 structs. So, we recurse through their fields here. */
3393 {
3398 cant_have_const_ctor,
3399 no_const_asn_ref);
3400 }
3401 /* Check members with class type for constructors, destructors,
3402 etc. */
3404 {
3405 /* Never let anything with uninheritable virtuals
3406 make it through without complaint. */
3410 {
3415 field);
3420 field);
3422 {
3426 }
3427 }
3428 else
3429 {
3442 }
3451 }
3456 /* `build_class_init_list' does not recognize
3457 non-FIELD_DECLs. */
3461 }
3463 /* Check the data members (both static and non-static), class-scoped
3464 typedefs, etc., appearing in the declaration of T. Issue
3465 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3466 declaration order) of access declarations; each TREE_VALUE in this
3467 list is a USING_DECL.
3469 In addition, set the following flags:
3471 EMPTY_P
3472 The class is empty, i.e., contains no non-static data members.
3474 CANT_HAVE_CONST_CTOR_P
3475 This class cannot have an implicitly generated copy constructor
3476 taking a const reference.
3478 CANT_HAVE_CONST_ASN_REF
3479 This class cannot have an implicitly generated assignment
3480 operator taking a const reference.
3482 All of these flags should be initialized before calling this
3483 function.
3485 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3486 fields can be added by adding to this chain. */
3488 static void
3492 {
3500 /* Assume there are no access declarations. */
3502 /* Assume this class has no pointer members. */
3504 /* Assume none of the members of this class have default
3505 initializations. */
3509 {
3517 {
3518 /* Save the access declarations for our caller. */
3521 }
3528 /* FIXME: We should fold in the checking from check_methods. */
3531 /* If we've gotten this far, it's a data member, possibly static,
3532 or an enumerator. */
3536 /* When this goes into scope, it will be a non-local reference. */
3540 {
3541 /* [class.union] (C++98)
3543 If a union contains a static data member, or a member of
3544 reference type, the program is ill-formed.
3546 In C++11 [class.union] says:
3547 If a union contains a non-static data member of reference type
3548 the program is ill-formed. */
3550 {
3554 }
3557 {
3561 }
3562 }
3564 /* Perform error checking that did not get done in
3565 grokdeclarator. */
3567 {
3571 }
3573 {
3577 }
3585 /* Now it can only be a FIELD_DECL. */
3590 /* If at least one non-static data member is non-literal, the whole
3591 class becomes non-literal. Per Core/1453, volatile non-static
3592 data members and base classes are also not allowed.
3593 Note: if the type is incomplete we will complain later on. */
3598 /* A standard-layout class is a class that:
3599 ...
3600 has the same access control (Clause 11) for all non-static data members,
3601 ... */
3608 /* If this is of reference type, check if it needs an init. */
3610 {
3616 {
3617 /* ARM $12.6.2: [A member initializer list] (or, for an
3618 aggregate, initialization by a brace-enclosed list) is the
3619 only way to initialize nonstatic const and reference
3620 members. */
3623 }
3624 }
3629 {
3631 {
3632 warning_at
3635 x);
3637 }
3641 }
3644 /* We don't treat zero-width bitfields as making a class
3645 non-empty. */
3646 ;
3647 else
3648 {
3649 /* The class is non-empty. */
3651 /* The class is not even nearly empty. */
3653 /* If one of the data members contains an empty class,
3654 so does T. */
3658 }
3660 /* This is used by -Weffc++ (see below). Warn only for pointers
3661 to members which might hold dynamic memory. So do not warn
3662 for pointers to functions or pointers to members. */
3668 {
3673 }
3679 {
3681 {
3685 }
3687 {
3691 }
3692 }
3695 /* DR 148 now allows pointers to members (which are POD themselves),
3696 to be allowed in POD structs. */
3705 /* We set DECL_C_BIT_FIELD in grokbitfield.
3706 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3709 cant_have_const_ctor_p,
3710 no_const_asn_ref_p))
3711 {
3716 }
3718 /* Now that we've removed bit-field widths from DECL_INITIAL,
3719 anything left in DECL_INITIAL is an NSDMI that makes the class
3720 non-aggregate in C++11. */
3724 /* If any field is const, the structure type is pseudo-const. */
3726 {
3731 {
3732 /* ARM $12.6.2: [A member initializer list] (or, for an
3733 aggregate, initialization by a brace-enclosed list) is the
3734 only way to initialize nonstatic const and reference
3735 members. */
3738 }
3739 }
3740 /* A field that is pseudo-const makes the structure likewise. */
3742 {
3747 }
3749 /* Core issue 80: A nonstatic data member is required to have a
3750 different name from the class iff the class has a
3751 user-declared constructor. */
3756 }
3758 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3759 it should also define a copy constructor and an assignment operator to
3760 implement the correct copy semantic (deep vs shallow, etc.). As it is
3761 not feasible to check whether the constructors do allocate dynamic memory
3762 and store it within members, we approximate the warning like this:
3764 -- Warn only if there are members which are pointers
3765 -- Warn only if there is a non-trivial constructor (otherwise,
3766 there cannot be memory allocated).
3767 -- Warn only if there is a non-trivial destructor. We assume that the
3768 user at least implemented the cleanup correctly, and a destructor
3769 is needed to free dynamic memory.
3771 This seems enough for practical purposes. */
3773 && has_pointers
3777 {
3781 {
3786 }
3790 }
3792 /* Non-static data member initializers make the default constructor
3793 non-trivial. */
3795 {
3798 }
3800 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3804 /* Check anonymous struct/anonymous union fields. */
3807 /* We've built up the list of access declarations in reverse order.
3808 Fix that now. */
3810 }
3812 /* If TYPE is an empty class type, records its OFFSET in the table of
3813 OFFSETS. */
3815 static int
3817 {
3818 splay_tree_node n;
3823 /* Record the location of this empty object in OFFSETS. */
3831 type,
3835 }
3837 /* Returns nonzero if TYPE is an empty class type and there is
3838 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3840 static int
3842 {
3843 splay_tree_node n;
3844 tree t;
3849 /* Record the location of this empty object in OFFSETS. */
3859 }
3861 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3862 F for every subobject, passing it the type, offset, and table of
3863 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3864 be traversed.
3866 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3867 than MAX_OFFSET will not be walked.
3869 If F returns a nonzero value, the traversal ceases, and that value
3870 is returned. Otherwise, returns zero. */
3872 static int
3874 subobject_offset_fn f,
3875 tree offset,
3876 splay_tree offsets,
3877 tree max_offset,
3879 {
3883 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3884 stop. */
3892 {
3895 }
3898 {
3899 tree field;
3900 tree binfo;
3903 /* Avoid recursing into objects that are not interesting. */
3907 /* Record the location of TYPE. */
3912 /* Iterate through the direct base classes of TYPE. */
3916 {
3917 tree binfo_offset;
3922 tree orig_binfo;
3923 /* We cannot rely on BINFO_OFFSET being set for the base
3924 class yet, but the offsets for direct non-virtual
3925 bases can be calculated by going back to the TYPE. */
3928 offset,
3932 f,
3933 binfo_offset,
3934 offsets,
3935 max_offset,
3939 }
3942 {
3946 /* Iterate through the virtual base classes of TYPE. In G++
3947 3.2, we included virtual bases in the direct base class
3948 loop above, which results in incorrect results; the
3949 correct offsets for virtual bases are only known when
3950 working with the most derived type. */
3954 {
3956 f,
3958 offset,
3960 offsets,
3961 max_offset,
3965 }
3966 else
3967 {
3968 /* We still have to walk the primary base, if it is
3969 virtual. (If it is non-virtual, then it was walked
3970 above.) */
3976 {
3977 r = (walk_subobject_offsets
3982 }
3983 }
3984 }
3986 /* Iterate through the fields of TYPE. */
3991 {
3992 tree field_offset;
3997 f,
3999 offset,
4000 field_offset),
4001 offsets,
4002 max_offset,
4006 }
4007 }
4009 {
4012 tree index;
4014 /* Avoid recursing into objects that are not interesting. */
4017 || !domain
4021 /* Step through each of the elements in the array. */
4025 {
4027 f,
4028 offset,
4029 offsets,
4030 max_offset,
4036 /* If this new OFFSET is bigger than the MAX_OFFSET, then
4037 there's no point in iterating through the remaining
4038 elements of the array. */
4041 }
4042 }
4045 }
4047 /* Record all of the empty subobjects of TYPE (either a type or a
4048 binfo). If IS_DATA_MEMBER is true, then a non-static data member
4049 is being placed at OFFSET; otherwise, it is a base class that is
4050 being placed at OFFSET. */
4052 static void
4054 tree offset,
4055 splay_tree offsets,
4057 {
4058 tree max_offset;
4059 /* If recording subobjects for a non-static data member or a
4060 non-empty base class , we do not need to record offsets beyond
4061 the size of the biggest empty class. Additional data members
4062 will go at the end of the class. Additional base classes will go
4063 either at offset zero (if empty, in which case they cannot
4064 overlap with offsets past the size of the biggest empty class) or
4065 at the end of the class.
4067 However, if we are placing an empty base class, then we must record
4068 all offsets, as either the empty class is at offset zero (where
4069 other empty classes might later be placed) or at the end of the
4070 class (where other objects might then be placed, so other empty
4071 subobjects might later overlap). */
4075 else
4079 }
4081 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4082 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4083 virtual bases of TYPE are examined. */
4085 static int
4087 tree offset,
4088 splay_tree offsets,
4090 {
4091 splay_tree_node max_node;
4093 /* Get the node in OFFSETS that indicates the maximum offset where
4094 an empty subobject is located. */
4096 /* If there aren't any empty subobjects, then there's no point in
4097 performing this check. */
4103 vbases_p);
4104 }
4106 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4107 non-static data member of the type indicated by RLI. BINFO is the
4108 binfo corresponding to the base subobject, OFFSETS maps offsets to
4109 types already located at those offsets. This function determines
4110 the position of the DECL. */
4112 static void
4114 tree decl,
4115 tree binfo,
4116 splay_tree offsets)
4117 {
4120 tree type;
4123 {
4124 /* For the purposes of determining layout conflicts, we want to
4125 use the class type of BINFO; TREE_TYPE (DECL) will be the
4126 CLASSTYPE_AS_BASE version, which does not contain entries for
4127 zero-sized bases. */
4130 }
4131 else
4132 {
4135 }
4137 /* Try to place the field. It may take more than one try if we have
4138 a hard time placing the field without putting two objects of the
4139 same type at the same address. */
4141 {
4144 /* Place this field. */
4148 /* We have to check to see whether or not there is already
4149 something of the same type at the offset we're about to use.
4150 For example, consider:
4152 struct S {};
4153 struct T : public S { int i; };
4154 struct U : public S, public T {};
4156 Here, we put S at offset zero in U. Then, we can't put T at
4157 offset zero -- its S component would be at the same address
4158 as the S we already allocated. So, we have to skip ahead.
4159 Since all data members, including those whose type is an
4160 empty class, have nonzero size, any overlap can happen only
4161 with a direct or indirect base-class -- it can't happen with
4162 a data member. */
4163 /* In a union, overlap is permitted; all members are placed at
4164 offset zero. */
4169 {
4170 /* Strip off the size allocated to this field. That puts us
4171 at the first place we could have put the field with
4172 proper alignment. */
4175 /* Bump up by the alignment required for the type. */
4176 rli->bitpos
4182 }
4185 {
4186 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4187 the offset wasn't aligned like a pointer when we started to
4188 layout this field, that affects its position. */
4191 {
4194 "alignment of %qD increased in -fabi-version=9 "
4196 else
4199 }
4201 }
4202 else
4203 /* There was no conflict. We're done laying out this field. */
4205 }
4207 /* Now that we know where it will be placed, update its
4208 BINFO_OFFSET. */
4210 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4211 this point because their BINFO_OFFSET is copied from another
4212 hierarchy. Therefore, we may not need to add the entire
4213 OFFSET. */
4219 }
4221 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4223 static int
4225 tree offset,
4227 {
4229 }
4231 /* Layout the empty base BINFO. EOC indicates the byte currently just
4232 past the end of the class, and should be correctly aligned for a
4233 class of the type indicated by BINFO; OFFSETS gives the offsets of
4234 the empty bases allocated so far. T is the most derived
4235 type. Return nonzero iff we added it at the end. */
4237 static bool
4240 {
4241 tree alignment;
4245 /* This routine should only be used for empty classes. */
4250 propagate_binfo_offsets
4254 /* This is an empty base class. We first try to put it at offset
4255 zero. */
4258 offsets,
4260 {
4261 /* That didn't work. Now, we move forward from the next
4262 available spot in the class. */
4266 {
4269 offsets,
4271 /* We finally found a spot where there's no overlap. */
4274 /* There's overlap here, too. Bump along to the next spot. */
4276 }
4277 }
4280 {
4285 }
4288 }
4290 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4291 fields at NEXT_FIELD, and return it. */
4293 static tree
4295 {
4296 /* Create the FIELD_DECL. */
4310 /* Add the new FIELD_DECL to the list of fields for T. */
4316 }
4318 /* Layout the base given by BINFO in the class indicated by RLI.
4319 *BASE_ALIGN is a running maximum of the alignments of
4320 any base class. OFFSETS gives the location of empty base
4321 subobjects. T is the most derived type. Return nonzero if the new
4322 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4323 *NEXT_FIELD, unless BINFO is for an empty base class.
4325 Returns the location at which the next field should be inserted. */
4330 {
4335 /* This error is now reported in xref_tag, thus giving better
4336 location information. */
4339 /* Place the base class. */
4341 {
4342 tree decl;
4344 /* The containing class is non-empty because it has a non-empty
4345 base class. */
4348 /* Create the FIELD_DECL. */
4351 /* Try to place the field. It may take more than one try if we
4352 have a hard time placing the field without putting two
4353 objects of the same type at the same address. */
4355 }
4356 else
4357 {
4358 tree eoc;
4361 /* On some platforms (ARM), even empty classes will not be
4362 byte-aligned. */
4367 /* A nearly-empty class "has no proper base class that is empty,
4368 not morally virtual, and at an offset other than zero." */
4370 {
4373 /* The check above (used in G++ 3.2) is insufficient because
4374 an empty class placed at offset zero might itself have an
4375 empty base at a nonzero offset. */
4377 empty_base_at_nonzero_offset_p,
4378 size_zero_node,
4383 }
4385 /* We used to not create a FIELD_DECL for empty base classes because of
4386 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4387 be a problem anymore. We need them to handle initialization of C++17
4388 aggregate bases. */
4390 {
4395 }
4397 /* An empty virtual base causes a class to be non-empty
4398 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4399 here because that was already done when the virtual table
4400 pointer was created. */
4401 }
4403 /* Record the offsets of BINFO and its base subobjects. */
4406 offsets,
4410 }
4412 /* Layout all of the non-virtual base classes. Record empty
4413 subobjects in OFFSETS. T is the most derived type. Return nonzero
4414 if the type cannot be nearly empty. The fields created
4415 corresponding to the base classes will be inserted at
4416 *NEXT_FIELD. */
4418 static void
4421 {
4422 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4423 subobjects. */
4428 /* The primary base class is always allocated first. */
4433 /* Now allocate the rest of the bases. */
4435 {
4436 tree base_binfo;
4440 /* The primary base was already allocated above, so we don't
4441 need to allocate it again here. */
4445 /* Virtual bases are added at the end (a primary virtual base
4446 will have already been added). */
4452 }
4453 }
4455 /* Go through the TYPE_FIELDS of T issuing any appropriate
4456 diagnostics, figuring out which methods override which other
4457 methods, and so forth. */
4459 static void
4461 {
4464 {
4470 /* The name of the field is the original field name
4471 Save this in auxiliary field for later overloading. */
4473 {
4477 }
4479 /* All user-provided destructors are non-trivial.
4480 Constructors and assignment ops are handled in
4481 grok_special_member_properties. */
4488 "%<transaction_safe_dynamic%> may only be specified for "
4490 }
4491 }
4493 /* FN is a constructor or destructor. Clone the declaration to create
4494 a specialized in-charge or not-in-charge version, as indicated by
4495 NAME. */
4497 static tree
4499 {
4500 tree parms;
4501 tree clone;
4503 /* Copy the function. */
4505 /* Reset the function name. */
4507 /* Remember where this function came from. */
4509 /* Make it easy to find the CLONE given the FN. */
4513 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4515 {
4522 }
4523 else
4524 {
4525 // Clone constraints.
4529 }
4534 /* There's no pending inline data for this function. */
4538 /* The base-class destructor is not virtual. */
4540 {
4544 }
4550 /* If there was an in-charge parameter, drop it from the function
4551 type. */
4553 {
4554 tree basetype;
4555 tree parmtypes;
4556 tree exceptions;
4561 /* Skip the `this' parameter. */
4563 /* Skip the in-charge parameter. */
4565 /* And the VTT parm, in a complete [cd]tor. */
4570 {
4571 /* If we're omitting inherited parms, that just leaves the VTT. */
4574 }
4578 parmtypes);
4581 exceptions);
4585 }
4587 /* Copy the function parameters. */
4589 /* Remove the in-charge parameter. */
4591 {
4595 }
4596 /* And the VTT parm, in a complete [cd]tor. */
4598 {
4601 else
4602 {
4606 }
4607 }
4609 /* A base constructor inheriting from a virtual base doesn't get the
4610 arguments. */
4615 {
4618 }
4620 /* Create the RTL for this function. */
4625 }
4627 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4628 not invoke this function directly.
4630 For a non-thunk function, returns the address of the slot for storing
4631 the function it is a clone of. Otherwise returns NULL_TREE.
4633 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4634 cloned_function is unset. This is to support the separate
4635 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4636 on a template makes sense, but not the former. */
4638 tree *
4640 {
4648 {
4649 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4652 else
4653 #endif
4655 }
4660 else
4662 }
4664 /* Produce declarations for all appropriate clones of FN. If
4665 UPDATE_METHODS is true, the clones are added to the
4666 CLASSTYPE_METHOD_VEC. */
4668 void
4670 {
4671 tree clone;
4673 /* Avoid inappropriate cloning. */
4679 {
4680 /* For each constructor, we need two variants: an in-charge version
4681 and a not-in-charge version. */
4688 }
4689 else
4690 {
4693 /* For each destructor, we need three variants: an in-charge
4694 version, a not-in-charge version, and an in-charge deleting
4695 version. We clone the deleting version first because that
4696 means it will go second on the TYPE_FIELDS list -- and that
4697 corresponds to the correct layout order in the virtual
4698 function table.
4700 For a non-virtual destructor, we do not build a deleting
4701 destructor. */
4703 {
4707 }
4714 }
4716 /* Note that this is an abstract function that is never emitted. */
4718 }
4720 /* DECL is an in charge constructor, which is being defined. This will
4721 have had an in class declaration, from whence clones were
4722 declared. An out-of-class definition can specify additional default
4723 arguments. As it is the clones that are involved in overload
4724 resolution, we must propagate the information from the DECL to its
4725 clones. */
4727 void
4729 {
4730 tree clone;
4734 {
4741 /* Skip the 'this' parameter. */
4757 {
4759 {
4763 }
4769 {
4770 /* A default parameter has been added. Adjust the
4771 clone's parameters. */
4775 tree type;
4780 {
4783 clone_parms);
4785 }
4788 clone_parms);
4797 }
4798 }
4800 }
4801 }
4803 /* For each of the constructors and destructors in T, create an
4804 in-charge and not-in-charge variant. */
4806 static void
4808 {
4809 /* While constructors can be via a using declaration, at this point
4810 we no longer need to know that. */
4816 }
4818 /* Deduce noexcept for a destructor DTOR. */
4820 void
4822 {
4825 noexcept_deferred_spec);
4826 }
4828 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4829 of TYPE for virtual functions which FNDECL overrides. Return a
4830 mask of the tm attributes found therein. */
4832 static int
4834 {
4836 tree base_binfo;
4840 {
4848 {
4852 else
4855 }
4856 else
4858 }
4861 }
4863 /* Subroutine of set_method_tm_attributes. Handle the checks and
4864 inheritance for one virtual method FNDECL. */
4866 static void
4868 {
4869 tree tm_attr;
4874 /* If FNDECL doesn't actually override anything (i.e. T is the
4875 class that first declares FNDECL virtual), then we're done. */
4882 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4883 tm_pure must match exactly, otherwise no weakening of
4884 tm_safe > tm_callable > nothing. */
4885 /* ??? The tm_pure attribute didn't make the transition to the
4886 multivendor language spec. */
4888 {
4890 {
4893 }
4894 }
4895 /* If the overridden function is tm_pure, then FNDECL must be. */
4898 /* Look for base class combinations that cannot be satisfied. */
4900 {
4906 }
4907 /* If FNDECL did not declare an attribute, then inherit the most
4908 restrictive one. */
4910 {
4912 }
4913 /* Otherwise validate that we're not weaker than a function
4914 that is being overridden. */
4915 else
4916 {
4920 }
4923 err_override:
4927 }
4929 /* For each of the methods in T, propagate a class-level tm attribute. */
4931 static void
4933 {
4936 /* Don't bother collecting tm attributes if transactional memory
4937 support is not enabled. */
4941 /* Process virtual methods first, as they inherit directly from the
4942 base virtual function and also require validation of new attributes. */
4944 {
4945 tree vchain;
4948 {
4953 }
4954 }
4956 /* If the class doesn't have an attribute, nothing more to do. */
4961 /* Any method that does not yet have a tm attribute inherits
4962 the one from the class. */
4967 }
4969 /* Returns true if FN is a default constructor. */
4971 bool
4973 {
4976 }
4978 /* Returns true iff class T has a user-defined constructor that can be called
4979 with more than zero arguments. */
4981 bool
4983 {
4988 {
4995 }
4998 }
5000 /* Returns the defaulted constructor if T has one. Otherwise, returns
5001 NULL_TREE. */
5003 tree
5005 {
5010 {
5016 }
5019 }
5021 /* Returns true iff FN is a user-provided function, i.e. user-declared
5022 and not defaulted at its first declaration. */
5024 bool
5026 {
5029 else
5033 }
5035 /* Returns true iff class T has a user-provided constructor. */
5037 bool
5039 {
5051 }
5053 /* Returns true iff class T has a user-provided or explicit constructor. */
5055 bool
5057 {
5065 {
5069 }
5072 }
5074 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5075 declared or explicitly defaulted in the class body) default
5076 constructor. */
5078 bool
5080 {
5087 {
5093 }
5096 }
5098 /* TYPE is being used as a virtual base, and has a non-trivial move
5099 assignment. Return true if this is due to there being a user-provided
5100 move assignment in TYPE or one of its subobjects; if there isn't, then
5101 multiple move assignment can't cause any harm. */
5103 bool
5105 {
5106 /* Does the type itself have a user-provided move assignment operator? */
5110 {
5114 }
5116 /* Do any of its bases? */
5118 tree base_binfo;
5123 /* Or non-static data members? */
5125 {
5130 }
5132 /* Seems not. */
5134 }
5136 /* If default-initialization leaves part of TYPE uninitialized, returns
5137 a DECL for the field or TYPE itself (DR 253). */
5139 tree
5141 {
5152 {
5156 }
5161 {
5165 }
5168 }
5170 /* Returns true iff for class T, a trivial synthesized default constructor
5171 would be constexpr. */
5173 bool
5175 {
5176 /* A defaulted trivial default constructor is constexpr
5177 if there is nothing to initialize. */
5180 }
5182 /* Returns true iff class T has a constexpr default constructor. */
5184 bool
5186 {
5187 tree fns;
5190 {
5191 /* The caller should have stripped an enclosing array. */
5194 }
5196 {
5199 /* Non-trivial, we need to check subobject constructors. */
5201 }
5204 }
5206 /* Returns true iff class T has a constexpr default constructor or has an
5207 implicitly declared default constructor that we can't tell if it's constexpr
5208 without forcing a lazy declaration (which might cause undesired
5209 instantiations). */
5211 bool
5213 {
5216 /* Assume it's constexpr. */
5219 }
5221 /* Returns true iff class TYPE has a virtual destructor. */
5223 bool
5225 {
5226 tree dtor;
5234 }
5236 /* Returns true iff T, a class, has a move-assignment or
5237 move-constructor. Does not lazily declare either.
5238 If USER_P is false, any move function will do. If it is true, the
5239 move function must be user-declared.
5241 Note that user-declared here is different from "user-provided",
5242 which doesn't include functions that are defaulted in the
5243 class. */
5245 bool
5247 {
5266 }
5268 /* Nonzero if we need to build up a constructor call when initializing an
5269 object of this class, either because it has a user-declared constructor
5270 or because it doesn't have a default constructor (so we need to give an
5271 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5272 what you care about is whether or not an object can be produced by a
5273 constructor (e.g. so we don't set TREE_READONLY on const variables of
5274 such type); use this function when what you care about is whether or not
5275 to try to call a constructor to create an object. The latter case is
5276 the former plus some cases of constructors that cannot be called. */
5278 bool
5280 {
5281 tree inner;
5291 /* A user-declared constructor might be private, and a constructor might
5292 be trivial but deleted. */
5296 {
5301 }
5303 }
5305 /* Like type_build_ctor_call, but for destructors. */
5307 bool
5309 {
5310 tree inner;
5319 /* A user-declared destructor might be private, and a destructor might
5320 be trivial but deleted. */
5324 {
5329 }
5331 }
5333 /* Remove all zero-width bit-fields from T. */
5335 static void
5337 {
5342 {
5345 /* We should not be confused by the fact that grokbitfield
5346 temporarily sets the width of the bit field into
5347 DECL_INITIAL (*fieldsp).
5348 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5349 to that width. */
5353 else
5355 }
5356 }
5358 /* Returns TRUE iff we need a cookie when dynamically allocating an
5359 array whose elements have the indicated class TYPE. */
5361 static bool
5363 {
5364 tree fns;
5369 /* If there's a non-trivial destructor, we need a cookie. In order
5370 to iterate through the array calling the destructor for each
5371 element, we'll have to know how many elements there are. */
5375 /* If the usual deallocation function is a two-argument whose second
5376 argument is of type `size_t', then we have to pass the size of
5377 the array to the deallocation function, so we will need to store
5378 a cookie. */
5382 /* If there are no `operator []' members, or the lookup is
5383 ambiguous, then we don't need a cookie. */
5386 /* Loop through all of the functions. */
5388 {
5391 /* See if this function is a one-argument delete function. If
5392 it is, then it will be the usual deallocation function. */
5396 /* Do not consider this function if its second argument is an
5397 ellipsis. */
5400 /* Otherwise, if we have a two-argument function and the second
5401 argument is `size_t', it will be the usual deallocation
5402 function -- unless there is one-argument function, too. */
5406 }
5409 }
5411 /* Finish computing the `literal type' property of class type T.
5413 At this point, we have already processed base classes and
5414 non-static data members. We need to check whether the copy
5415 constructor is trivial, the destructor is trivial, and there
5416 is a trivial default constructor or at least one constexpr
5417 constructor other than the copy constructor. */
5419 static void
5421 {
5422 tree fn;
5434 /* C++14 DR 1684 removed this restriction. */
5442 {
5446 "enclosing class of constexpr non-static member "
5449 }
5450 }
5452 /* T is a non-literal type used in a context which requires a constant
5453 expression. Explain why it isn't literal. */
5455 void
5457 {
5467 /* Already explained. */
5480 {
5482 "default constructor, and has no constexpr constructor that "
5485 /* Note that we can't simply call locate_ctor because when the
5486 constructor is deleted it just returns NULL_TREE. */
5488 {
5495 {
5498 else
5501 }
5502 }
5503 }
5504 else
5505 {
5509 {
5512 {
5517 }
5518 }
5520 {
5521 tree ftype;
5526 {
5529 field);
5532 }
5536 }
5537 }
5538 }
5540 /* Check the validity of the bases and members declared in T. Add any
5541 implicitly-generated functions (like copy-constructors and
5542 assignment operators). Compute various flag bits (like
5543 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5544 level: i.e., independently of the ABI in use. */
5546 static void
5548 {
5549 /* Nonzero if the implicitly generated copy constructor should take
5550 a non-const reference argument. */
5552 /* Nonzero if the implicitly generated assignment operator
5553 should take a non-const reference argument. */
5555 tree access_decls;
5558 tree fn;
5560 /* By default, we use const reference arguments and generate default
5561 constructors. */
5565 /* Check all the base-classes and set FMEM members to point to arrays
5566 of potential interest. */
5569 /* Deduce noexcept on destructor. This needs to happen after we've set
5570 triviality flags appropriately for our bases. */
5575 /* Check all the method declarations. */
5578 /* Save the initial values of these flags which only indicate whether
5579 or not the class has user-provided functions. As we analyze the
5580 bases and members we can set these flags for other reasons. */
5584 /* Check all the data member declarations. We cannot call
5585 check_field_decls until we have called check_bases check_methods,
5586 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5587 being set appropriately. */
5592 /* A nearly-empty class has to be vptr-containing; a nearly empty
5593 class contains just a vptr. */
5597 /* Do some bookkeeping that will guide the generation of implicitly
5598 declared member functions. */
5601 /* We need to call a constructor for this class if it has a
5602 user-provided constructor, or if the default constructor is going
5603 to initialize the vptr. (This is not an if-and-only-if;
5604 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5605 themselves need constructing.) */
5608 /* [dcl.init.aggr]
5610 An aggregate is an array or a class with no user-provided
5611 constructors ... and no virtual functions.
5613 Again, other conditions for being an aggregate are checked
5614 elsewhere. */
5618 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5619 retain the old definition internally for ABI reasons. */
5628 /* If the only explicitly declared default constructor is user-provided,
5629 set TYPE_HAS_COMPLEX_DFLT. */
5635 /* Warn if a public base of a polymorphic type has an accessible
5636 non-virtual destructor. It is only now that we know the class is
5637 polymorphic. Although a polymorphic base will have a already
5638 been diagnosed during its definition, we warn on use too. */
5640 {
5643 tree base_binfo;
5647 {
5655 basetype);
5656 }
5657 }
5659 /* If the class has no user-declared constructor, but does have
5660 non-static const or reference data members that can never be
5661 initialized, issue a warning. */
5663 /* Classes with user-declared constructors are presumed to
5664 initialize these members. */
5666 /* Aggregates can be initialized with brace-enclosed
5667 initializers. */
5669 {
5670 tree field;
5673 {
5674 tree type;
5691 }
5692 }
5694 /* Synthesize any needed methods. */
5696 cant_have_const_ctor,
5697 no_const_asn_ref);
5699 /* Check defaulted declarations here so we have cant_have_const_ctor
5700 and don't need to worry about clones. */
5705 {
5708 {
5709 bool imp_const_p
5715 /* If the function is defaulted outside the class, we just
5716 give the synthesis error. */
5719 }
5721 }
5724 {
5725 /* "This class type is not an aggregate." */
5727 }
5729 /* Compute the 'literal type' property before we
5730 do anything with non-static member functions. */
5733 /* Create the in-charge and not-in-charge variants of constructors
5734 and destructors. */
5737 /* Process the using-declarations. */
5741 /* Figure out whether or not we will need a cookie when dynamically
5742 allocating an array of this type. */
5745 }
5747 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5748 accordingly. If a new vfield was created (because T doesn't have a
5749 primary base class), then the newly created field is returned. It
5750 is not added to the TYPE_FIELDS list; it is the caller's
5751 responsibility to do that. Accumulate declared virtual functions
5752 on VIRTUALS_P. */
5754 static tree
5756 {
5757 tree fn;
5759 /* Collect the virtual functions declared in T. */
5764 {
5773 }
5775 /* If we couldn't find an appropriate base class, create a new field
5776 here. Even if there weren't any new virtual functions, we might need a
5777 new virtual function table if we're supposed to include vptrs in
5778 all classes that need them. */
5780 {
5781 /* We build this decl with vtbl_ptr_type_node, which is a
5782 `vtable_entry_type*'. It might seem more precise to use
5783 `vtable_entry_type (*)[N]' where N is the number of virtual
5784 functions. However, that would require the vtable pointer in
5785 base classes to have a different type than the vtable pointer
5786 in derived classes. We could make that happen, but that
5787 still wouldn't solve all the problems. In particular, the
5788 type-based alias analysis code would decide that assignments
5789 to the base class vtable pointer can't alias assignments to
5790 the derived class vtable pointer, since they have different
5791 types. Thus, in a derived class destructor, where the base
5792 class constructor was inlined, we could generate bad code for
5793 setting up the vtable pointer.
5795 Therefore, we use one type for all vtable pointers. We still
5796 use a type-correct type; it's just doesn't indicate the array
5797 bounds. That's better than using `void*' or some such; it's
5798 cleaner, and it let's the alias analysis code know that these
5799 stores cannot alias stores to void*! */
5800 tree field;
5813 /* This class is non-empty. */
5817 }
5820 }
5822 /* Add OFFSET to all base types of BINFO which is a base in the
5823 hierarchy dominated by T.
5825 OFFSET, which is a type offset, is number of bytes. */
5827 static void
5829 {
5831 tree primary_binfo;
5832 tree base_binfo;
5834 /* Update BINFO's offset. */
5839 offset));
5841 /* Find the primary base class. */
5847 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5848 downwards. */
5850 {
5851 /* Don't do the primary base twice. */
5859 }
5860 }
5862 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5863 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5864 empty subobjects of T. */
5866 static void
5868 {
5869 tree vbase;
5876 /* Find the last field. The artificial fields created for virtual
5877 bases will go after the last extant field to date. */
5882 /* Go through the virtual bases, allocating space for each virtual
5883 base that is not already a primary base class. These are
5884 allocated in inheritance graph order. */
5886 {
5891 {
5892 /* This virtual base is not a primary base of any class in the
5893 hierarchy, so we have to add space for it. */
5896 }
5897 }
5898 }
5900 /* Returns the offset of the byte just past the end of the base class
5901 BINFO. */
5903 static tree
5905 {
5906 tree size;
5911 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5912 allocate some space for it. It cannot have virtual bases, so
5913 TYPE_SIZE_UNIT is fine. */
5915 else
5919 }
5921 /* Returns the offset of the byte just past the end of the base class
5922 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
5923 only non-virtual bases are included. */
5925 static tree
5927 {
5930 tree binfo;
5931 tree base_binfo;
5932 tree offset;
5937 {
5947 }
5952 {
5956 }
5959 }
5961 /* Warn about bases of T that are inaccessible because they are
5962 ambiguous. For example:
5964 struct S {};
5965 struct T : public S {};
5966 struct U : public S, public T {};
5968 Here, `(S*) new U' is not allowed because there are two `S'
5969 subobjects of U. */
5971 static void
5973 {
5976 tree basetype;
5977 tree binfo;
5978 tree base_binfo;
5980 /* If there are no repeated bases, nothing can be ambiguous. */
5984 /* Check direct bases. */
5987 {
5993 }
5995 /* Check for ambiguous virtual bases. */
5999 {
6005 }
6006 }
6008 /* Compare two INTEGER_CSTs K1 and K2. */
6010 static int
6012 {
6014 }
6016 /* Increase the size indicated in RLI to account for empty classes
6017 that are "off the end" of the class. */
6019 static void
6021 {
6022 tree eoc;
6023 tree rli_size;
6025 /* It might be the case that we grew the class to allocate a
6026 zero-sized base class. That won't be reflected in RLI, yet,
6027 because we are willing to overlay multiple bases at the same
6028 offset. However, now we need to make sure that RLI is big enough
6029 to reflect the entire class. */
6034 {
6035 /* The size should have been rounded to a whole byte. */
6038 rli->bitpos
6047 }
6048 }
6050 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
6051 BINFO_OFFSETs for all of the base-classes. Position the vtable
6052 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
6054 static void
6056 {
6057 tree non_static_data_members;
6058 tree field;
6059 tree vptr;
6060 record_layout_info rli;
6061 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6062 types that appear at that offset. */
6063 splay_tree empty_base_offsets;
6064 /* True if the last field laid out was a bit-field. */
6066 /* The location at which the next field should be inserted. */
6068 /* T, as a base class. */
6069 tree base_t;
6071 /* Keep track of the first non-static data member. */
6074 /* Start laying out the record. */
6077 /* Mark all the primary bases in the hierarchy. */
6080 /* Create a pointer to our virtual function table. */
6083 /* The vptr is always the first thing in the class. */
6085 {
6090 }
6091 else
6094 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6099 /* Layout the non-static data members. */
6101 {
6102 tree type;
6103 tree padding;
6105 /* We still pass things that aren't non-static data members to
6106 the back end, in case it wants to do something with them. */
6108 {
6110 /* If the static data member has incomplete type, keep track
6111 of it so that it can be completed later. (The handling
6112 of pending statics in finish_record_layout is
6113 insufficient; consider:
6115 struct S1;
6116 struct S2 { static S1 s1; };
6118 At this point, finish_record_layout will be called, but
6119 S1 is still incomplete.) */
6121 {
6123 /* The visibility of static data members is determined
6124 at their point of declaration, not their point of
6125 definition. */
6127 }
6129 }
6137 /* If this field is a bit-field whose width is greater than its
6138 type, then there are some special rules for allocating
6139 it. */
6142 {
6144 /* We must allocate the bits as if suitably aligned for the
6145 longest integer type that fits in this many bits. Then,
6146 we are supposed to use the left over bits as additional
6147 padding. */
6149 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6157 {
6159 /* Too big, so our current guess is what we want. */
6161 /* Not bigger than limit, ok */
6163 }
6165 /* Figure out how much additional padding is required. */
6167 /* In a union, the padding field must have the full width
6168 of the bit-field; all fields start at offset zero. */
6170 else
6177 /* An unnamed bitfield does not normally affect the
6178 alignment of the containing class on a target where
6179 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6180 make any exceptions for unnamed bitfields when the
6181 bitfields are longer than their types. Therefore, we
6182 temporarily give the field a name. */
6184 {
6187 }
6193 empty_base_offsets);
6196 /* Now that layout has been performed, set the size of the
6197 field to the size of its declared type; the rest of the
6198 field is effectively invisible. */
6200 /* We must also reset the DECL_MODE of the field. */
6202 }
6203 else
6205 empty_base_offsets);
6207 /* Remember the location of any empty classes in FIELD. */
6210 empty_base_offsets,
6213 /* If a bit-field does not immediately follow another bit-field,
6214 and yet it starts in the middle of a byte, we have failed to
6215 comply with the ABI. */
6218 /* The TREE_NO_WARNING flag gets set by Objective-C when
6219 laying out an Objective-C class. The ObjC ABI differs
6220 from the C++ ABI, and so we do not want a warning
6221 here. */
6223 && !last_field_was_bitfield
6226 bitsize_unit_node)))
6228 "offset of %qD is not ABI-compliant and may "
6231 /* The middle end uses the type of expressions to determine the
6232 possible range of expression values. In order to optimize
6233 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6234 must be made aware of the width of "i", via its type.
6236 Because C++ does not have integer types of arbitrary width,
6237 we must (for the purposes of the front end) convert from the
6238 type assigned here to the declared type of the bitfield
6239 whenever a bitfield expression is used as an rvalue.
6240 Similarly, when assigning a value to a bitfield, the value
6241 must be converted to the type given the bitfield here. */
6243 {
6248 {
6255 }
6256 }
6258 /* If we needed additional padding after this field, add it
6259 now. */
6261 {
6262 tree padding_field;
6265 FIELD_DECL,
6266 NULL_TREE,
6267 char_type_node);
6274 NULL_TREE,
6275 empty_base_offsets);
6276 }
6279 }
6282 {
6283 /* Make sure that we are on a byte boundary so that the size of
6284 the class without virtual bases will always be a round number
6285 of bytes. */
6288 }
6290 /* Delete all zero-width bit-fields from the list of fields. Now
6291 that the type is laid out they are no longer important. */
6294 /* Create the version of T used for virtual bases. We do not use
6295 make_class_type for this version; this is an artificial type. For
6296 a POD type, we just reuse T. */
6298 {
6301 /* Set the size and alignment for the new type. */
6302 tree eoc;
6304 /* If the ABI version is not at least two, and the last
6305 field was a bit-field, RLI may not be on a byte
6306 boundary. In particular, rli_size_unit_so_far might
6307 indicate the last complete byte, while rli_size_so_far
6308 indicates the total number of bits used. Therefore,
6309 rli_size_so_far, rather than rli_size_unit_so_far, is
6310 used to compute TYPE_SIZE_UNIT. */
6318 eoc);
6328 /* Copy the fields from T. */
6332 {
6336 }
6339 /* Record the base version of the type. */
6342 }
6343 else
6346 /* Every empty class contains an empty class. */
6350 /* Set the TYPE_DECL for this type to contain the right
6351 value for DECL_OFFSET, so that we can use it as part
6352 of a COMPONENT_REF for multiple inheritance. */
6355 /* Now fix up any virtual base class types that we left lying
6356 around. We must get these done before we try to lay out the
6357 virtual function table. As a side-effect, this will remove the
6358 base subobject fields. */
6361 /* Make sure that empty classes are reflected in RLI at this
6362 point. */
6365 /* Make sure not to create any structures with zero size. */
6371 /* If this is a non-POD, declaring it packed makes a difference to how it
6372 can be used as a field; don't let finalize_record_size undo it. */
6376 /* Let the back end lay out the type. */
6385 /* Warn about bases that can't be talked about due to ambiguity. */
6388 /* Now that we're done with layout, give the base fields the real types. */
6393 /* Clean up. */
6400 }
6402 /* Determine the "key method" for the class type indicated by TYPE,
6403 and set CLASSTYPE_KEY_METHOD accordingly. */
6405 void
6407 {
6408 tree method;
6415 /* The key method is the first non-pure virtual function that is not
6416 inline at the point of class definition. On some targets the
6417 key function may not be inline; those targets should not call
6418 this function until the end of the translation unit. */
6424 {
6427 }
6430 }
6432 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6433 class data member of non-zero size, otherwise false. */
6437 {
6445 {
6449 }
6452 }
6454 /* Used by find_flexarrays and related functions. */
6456 struct flexmems_t
6457 {
6458 /* The first flexible array member or non-zero array member found
6459 in the order of layout. */
6460 tree array;
6461 /* First non-static non-empty data member in the class or its bases. */
6462 tree first;
6463 /* The first non-static non-empty data member following either
6464 the flexible array member, if found, or the zero-length array member
6465 otherwise. AFTER[1] refers to the first such data member of a union
6466 of which the struct containing the flexible array member or zero-length
6467 array is a member, or NULL when no such union exists. This element is
6468 only used during searching, not for diagnosing problems. AFTER[0]
6469 refers to the first such data member that is not a member of such
6470 a union. */
6473 /* Refers to a struct (not union) in which the struct of which the flexible
6474 array is member is defined. Used to diagnose strictly (according to C)
6475 invalid uses of the latter structs. */
6476 tree enclosing;
6477 };
6479 /* Find either the first flexible array member or the first zero-length
6480 array, in that order of preference, among members of class T (but not
6481 its base classes), and set members of FMEM accordingly.
6482 BASE_P is true if T is a base class of another class.
6483 PUN is set to the outermost union in which the flexible array member
6484 (or zero-length array) is defined if one such union exists, otherwise
6485 to NULL.
6486 Similarly, PSTR is set to a data member of the outermost struct of
6487 which the flexible array is a member if one such struct exists,
6488 otherwise to NULL. */
6490 static void
6494 {
6495 /* Set the "pointer" to the outermost enclosing union if not set
6496 yet and maintain it for the remainder of the recursion. */
6501 {
6505 /* Is FLD a typedef for an anonymous struct? */
6507 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6508 handled elsewhere so that errors like the following are detected
6509 as well:
6510 typedef struct { int i, a[], j; } S; // bug c++/72753
6511 S s [2]; // bug c++/68489
6512 */
6517 {
6518 /* Check the nested unnamed type referenced via a typedef
6519 independently of FMEM (since it's not a data member of
6520 the enclosing class). */
6523 }
6525 /* Skip anything that's GCC-generated or not a (non-static) data
6526 member. */
6530 /* Type of the member. */
6535 /* Determine the type of the array element or object referenced
6536 by the member so that it can be checked for flexible array
6537 members if it hasn't been yet. */
6545 {
6547 {
6548 /* Once the member after the flexible array has been found
6549 we're done. */
6552 }
6555 {
6556 /* Descend into the non-static member struct or union and try
6557 to find a flexible array member or zero-length array among
6558 its members. This is only necessary for anonymous types
6559 and types in whose context the current type T has not been
6560 defined (the latter must not be checked again because they
6561 are already in the process of being checked by one of the
6562 recursive calls). */
6567 /* If this member isn't anonymous and a prior non-flexible array
6568 member has been seen in one of the enclosing structs, clear
6569 the FIRST member since it doesn't contribute to the flexible
6570 array struct's members. */
6581 {
6582 /* Restore the FIRST member reset above if no flexible
6583 array member has been found in this member's struct. */
6585 }
6587 /* If the member struct contains the first flexible array
6588 member, or if this member is a base class, continue to
6589 the next member and avoid setting the FMEM->NEXT pointer
6590 to point to it. */
6593 }
6594 }
6597 {
6598 /* Remember the first non-static data member. */
6602 /* Remember the first non-static data member after the flexible
6603 array member, if one has been found, or the zero-length array
6604 if it has been found. */
6607 }
6609 /* Skip non-arrays. */
6613 /* Determine the upper bound of the array if it has one. */
6615 {
6617 {
6618 /* Make a record of the zero-length array if either one
6619 such field or a flexible array member has been seen to
6620 handle the pathological and unlikely case of multiple
6621 such members. */
6624 }
6626 {
6627 /* Remember the first zero-length array unless a flexible array
6628 member has already been seen. */
6631 }
6632 }
6633 else
6634 {
6635 /* Flexible array members have no upper bound. */
6637 {
6638 /* Replace the zero-length array if it's been stored and
6639 reset the after pointer. */
6641 {
6645 }
6646 }
6647 else
6648 {
6651 }
6652 }
6653 }
6654 }
6656 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6657 a flexible array member (or the zero-length array extension). */
6659 static void
6661 {
6673 }
6675 /* Issue diagnostics for invalid flexible array members or zero-length
6676 arrays that are not the last elements of the containing class or its
6677 base classes or that are its sole members. */
6679 static void
6681 {
6686 {
6689 }
6691 /* Has a diagnostic been issued? */
6697 {
6704 {
6708 {
6711 }
6712 }
6713 }
6714 else
6715 {
6722 {
6728 /* In the unlikely event that the member following the flexible
6729 array member is declared in a different class, or the member
6730 overlaps another member of a common union, point to it.
6731 Otherwise it should be obvious. */
6735 {
6740 }
6741 }
6742 }
6746 }
6749 /* Recursively check to make sure that any flexible array or zero-length
6750 array members of class T or its bases are valid (i.e., not the sole
6751 non-static data member of T and, if one exists, that it is the last
6752 non-static data member of T and its base classes. FMEM is expected
6753 to be initially null and is used internally by recursive calls to
6754 the function. Issue the appropriate diagnostics for the array member
6755 that fails the checks. */
6757 static void
6760 {
6761 /* Initialize the result of a search for flexible array and zero-length
6762 array members. Avoid doing any work if the most interesting FMEM data
6763 have already been populated. */
6772 /* Recursively check the primary base class first. */
6774 {
6777 }
6779 /* Recursively check the base classes. */
6782 {
6785 /* The primary base class was already checked above. */
6789 /* Virtual base classes are at the end. */
6793 /* Check the base class. */
6795 }
6798 {
6799 /* Check virtual base classes only once per derived class.
6800 I.e., this check is not performed recursively for base
6801 classes. */
6803 tree base_binfo;
6807 {
6808 /* Check the virtual base class. */
6812 }
6813 }
6815 /* Is the type unnamed (and therefore a member of it potentially
6816 an anonymous struct or union)? */
6819 /* Search the members of the current (possibly derived) class, skipping
6820 unnamed structs and unions since those could be anonymous. */
6825 {
6826 /* Issue diagnostics for invalid flexible and zero-length array
6827 members found in base classes or among the members of the current
6828 class. Ignore anonymous structs and unions whose members are
6829 considered to be members of the enclosing class and thus will
6830 be diagnosed when checking it. */
6832 }
6833 }
6835 /* Perform processing required when the definition of T (a class type)
6836 is complete. Diagnose invalid definitions of flexible array members
6837 and zero-size arrays. */
6839 void
6841 {
6842 tree x;
6843 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6847 {
6852 }
6854 /* If this type was previously laid out as a forward reference,
6855 make sure we lay it out again. */
6859 /* Make assumptions about the class; we'll reset the flags if
6860 necessary. */
6866 /* Do end-of-class semantic processing: checking the validity of the
6867 bases and members and add implicitly generated methods. */
6870 /* Find the key method. */
6872 {
6873 /* The Itanium C++ ABI permits the key method to be chosen when
6874 the class is defined -- even though the key method so
6875 selected may later turn out to be an inline function. On
6876 some systems (such as ARM Symbian OS) the key method cannot
6877 be determined until the end of the translation unit. On such
6878 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6879 will cause the class to be added to KEYED_CLASSES. Then, in
6880 finish_file we will determine the key method. */
6884 /* If a polymorphic class has no key method, we may emit the vtable
6885 in every translation unit where the class definition appears. If
6886 we're devirtualizing, we can look into the vtable even if we
6887 aren't emitting it. */
6890 }
6892 /* Layout the class itself. */
6894 /* COMPLETE_TYPE_P is now true. */
6899 /* We use the base type for trivial assignments, and hence it
6900 needs a mode. */
6903 /* With the layout complete, check for flexible array members and
6904 zero-length arrays that might overlap other members in the final
6905 layout. */
6910 /* If necessary, create the primary vtable for this class. */
6912 {
6913 /* We must enter these virtuals into the table. */
6917 /* Here we know enough to change the type of our virtual
6918 function table, but we will wait until later this function. */
6921 /* If we're warning about ABI tags, check the types of the new
6922 virtual functions. */
6926 }
6929 {
6931 tree fn;
6938 /* Add entries for virtual functions introduced by this class. */
6942 /* Set DECL_VINDEX for all functions declared in this class. */
6944 fn;
6946 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6948 {
6952 /* A thunk. We should never be calling this entry directly
6953 from this vtable -- we'd use the entry for the non
6954 thunk base function. */
6958 }
6959 }
6967 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
6968 for any static member objects of the type we're working on. */
6977 /* Complain if one of the field types requires lower visibility. */
6980 /* Make the rtl for any new vtables we have created, and unmark
6981 the base types we marked. */
6984 /* Build the VTT for T. */
6991 "%q#T has virtual functions and accessible"
6999 /* Class layout, assignment of virtual table slots, etc., is now
7000 complete. Give the back end a chance to tweak the visibility of
7001 the class or perform any other required target modifications. */
7011 /* Finish debugging output for this type. */
7015 {
7018 {
7021 }
7023 {
7026 else
7027 {
7030 }
7032 }
7034 {
7036 "the type of the first field has a different ABI from the "
7039 }
7040 }
7041 }
7043 /* When T was built up, the member declarations were added in reverse
7044 order. Rearrange them to declaration order. */
7046 void
7048 {
7049 tree next;
7050 tree prev;
7051 tree x;
7053 /* The following lists are all in reverse order. Put them in
7054 declaration order now. */
7057 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
7058 order, so we can't just use nreverse. Due to stat_hack
7059 chicanery in finish_member_declarations. */
7064 {
7068 }
7071 {
7075 }
7076 }
7078 tree
7080 {
7083 /* Now that we've got all the field declarations, reverse everything
7084 as necessary. */
7090 /* Nadger the current location so that diagnostics point to the start of
7091 the struct, not the end. */
7095 {
7096 tree x;
7098 /* We need to add the target functions of USING_DECLS, so that
7099 they can be found when the using declaration is not
7100 instantiated yet. */
7103 {
7108 }
7114 /* COMPLETE_TYPE_P is now true. */
7118 /* We need to emit an error message if this type was used as a parameter
7119 and it is an abstract type, even if it is a template. We construct
7120 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7121 account and we call complete_vars with this type, which will check
7122 the PARM_DECLS. Note that while the type is being defined,
7123 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7124 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7131 /* Remember current #pragma pack value. */
7134 /* Fix up any variants we've already built. */
7136 {
7140 }
7141 }
7142 else
7144 /* COMPLETE_TYPE_P is now true. */
7149 {
7150 /* People keep complaining that the compiler crashes on an invalid
7151 definition of initializer_list, so I guess we should explicitly
7152 reject it. What the compiler internals care about is that it's a
7153 template and has a pointer field followed by an integer field. */
7156 {
7159 {
7163 }
7164 }
7167 "definition of std::initializer_list does not match "
7169 }
7177 else
7181 /* Lambdas are defined by the LAMBDA_EXPR. */
7186 }
7187 \f
7188 /* Hash table to avoid endless recursion when handling references. */
7191 /* Return the dynamic type of INSTANCE, if known.
7192 Used to determine whether the virtual function table is needed
7193 or not.
7195 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7196 of our knowledge of its type. *NONNULL should be initialized
7197 before this function is called. */
7199 static tree
7201 {
7202 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7205 {
7209 else
7213 /* This is a call to a constructor, hence it's never zero. */
7215 {
7219 }
7223 /* This is a call to a constructor, hence it's never zero. */
7225 {
7229 }
7238 /* Propagate nonnull. */
7243 CASE_CONVERT:
7249 {
7250 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7251 with a real object -- given &p->f, p can still be null. */
7253 /* ??? Probably should check DECL_WEAK here. */
7256 }
7260 /* If this component is really a base class reference, then the field
7261 itself isn't definitive. */
7270 {
7274 }
7275 /* fall through. */
7280 {
7284 }
7286 {
7290 /* if we're in a ctor or dtor, we know our type. If
7291 current_class_ptr is set but we aren't in a function, we're in
7292 an NSDMI (and therefore a constructor). */
7297 {
7301 }
7302 }
7304 {
7305 /* We only need one hash table because it is always left empty. */
7307 fixed_type_or_null_ref_ht
7310 /* Reference variables should be references to objects. */
7314 /* Enter the INSTANCE in a table to prevent recursion; a
7315 variable's initializer may refer to the variable
7316 itself. */
7321 {
7322 tree type;
7331 }
7332 }
7337 }
7338 #undef RECUR
7339 }
7341 /* Return nonzero if the dynamic type of INSTANCE is known, and
7342 equivalent to the static type. We also handle the case where
7343 INSTANCE is really a pointer. Return negative if this is a
7344 ctor/dtor. There the dynamic type is known, but this might not be
7345 the most derived base of the original object, and hence virtual
7346 bases may not be laid out according to this type.
7348 Used to determine whether the virtual function table is needed
7349 or not.
7351 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7352 of our knowledge of its type. *NONNULL should be initialized
7353 before this function is called. */
7355 int
7357 {
7360 tree fixed;
7362 /* processing_template_decl can be false in a template if we're in
7363 instantiate_non_dependent_expr, but we still want to suppress
7364 this check. */
7366 {
7367 /* In a template we only care about the type of the result. */
7371 }
7381 }
7383 \f
7384 void
7386 {
7389 current_class_stack
7397 }
7399 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7401 static void
7403 {
7404 tree type;
7406 /* We are re-entering the same class we just left, so we don't
7407 have to search the whole inheritance matrix to find all the
7408 decls to bind again. Instead, we install the cached
7409 class_shadowed list and walk through it binding names. */
7412 /* Restore IDENTIFIER_TYPE_VALUE. */
7414 type;
7417 }
7419 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7420 appropriate for TYPE.
7422 So that we may avoid calls to lookup_name, we cache the _TYPE
7423 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7425 For multiple inheritance, we perform a two-pass depth-first search
7426 of the type lattice. */
7428 void
7430 {
7431 class_stack_node_t csn;
7435 /* Make sure there is enough room for the new entry on the stack. */
7437 {
7439 current_class_stack
7441 current_class_stack_size);
7442 }
7444 /* Insert a new entry on the class stack. */
7451 current_class_depth++;
7453 /* Now set up the new type. */
7459 /* By default, things in classes are private, while things in
7460 structures or unions are public. */
7462 ? access_private_node
7468 {
7469 /* Forcibly remove any old class remnants. */
7471 }
7477 else
7479 }
7481 /* When we exit a toplevel class scope, we save its binding level so
7482 that we can restore it quickly. Here, we've entered some other
7483 class, so we must invalidate our cache. */
7485 void
7487 {
7489 }
7491 /* Get out of the current class scope. If we were in a class scope
7492 previously, that is the one popped to. */
7494 void
7496 {
7499 current_class_depth--;
7505 }
7507 /* Mark the top of the class stack as hidden. */
7509 void
7511 {
7514 }
7516 /* Mark the top of the class stack as un-hidden. */
7518 void
7520 {
7523 }
7525 /* Returns 1 if the class type currently being defined is either T or
7526 a nested type of T. Returns the type from the current_class_stack,
7527 which might be equivalent to but not equal to T in case of
7528 constrained partial specializations. */
7530 tree
7532 {
7540 /* We start looking from 1 because entry 0 is from global scope,
7541 and has no type. */
7543 {
7544 tree c;
7547 else
7548 {
7552 }
7557 }
7559 }
7561 /* If either current_class_type or one of its enclosing classes are derived
7562 from T, return the appropriate type. Used to determine how we found
7563 something via unqualified lookup. */
7565 tree
7567 {
7570 /* The bases of a dependent type are unknown. */
7581 {
7586 }
7589 }
7591 /* Return the outermost enclosing class type that is still open, or
7592 NULL_TREE. */
7594 tree
7596 {
7603 {
7610 }
7612 }
7614 /* Returns the innermost class type which is not a lambda closure type. */
7616 tree
7618 {
7623 }
7625 /* When entering a class scope, all enclosing class scopes' names with
7626 static meaning (static variables, static functions, types and
7627 enumerators) have to be visible. This recursive function calls
7628 pushclass for all enclosing class contexts until global or a local
7629 scope is reached. TYPE is the enclosed class. */
7631 void
7633 {
7634 /* A namespace might be passed in error cases, like A::B:C. */
7642 }
7644 /* Undoes a push_nested_class call. */
7646 void
7648 {
7654 }
7656 /* Returns the number of extern "LANG" blocks we are nested within. */
7658 int
7660 {
7662 }
7664 /* Set global variables CURRENT_LANG_NAME to appropriate value
7665 so that behavior of name-mangling machinery is correct. */
7667 void
7669 {
7676 else
7678 }
7680 /* Get out of the current language scope. */
7682 void
7684 {
7686 }
7687 \f
7688 /* Type instantiation routines. */
7690 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7691 matches the TARGET_TYPE. If there is no satisfactory match, return
7692 error_mark_node, and issue an error & warning messages under
7693 control of FLAGS. Permit pointers to member function if FLAGS
7694 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7695 a template-id, and EXPLICIT_TARGS are the explicitly provided
7696 template arguments.
7698 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7699 is the base path used to reference those member functions. If
7700 the address is resolved to a member function, access checks will be
7701 performed and errors issued if appropriate. */
7703 static tree
7705 tree overload,
7706 tsubst_flags_t complain,
7708 tree explicit_targs,
7709 tree access_path)
7710 {
7711 /* Here's what the standard says:
7713 [over.over]
7715 If the name is a function template, template argument deduction
7716 is done, and if the argument deduction succeeds, the deduced
7717 arguments are used to generate a single template function, which
7718 is added to the set of overloaded functions considered.
7720 Non-member functions and static member functions match targets of
7721 type "pointer-to-function" or "reference-to-function." Nonstatic
7722 member functions match targets of type "pointer-to-member
7723 function;" the function type of the pointer to member is used to
7724 select the member function from the set of overloaded member
7725 functions. If a nonstatic member function is selected, the
7726 reference to the overloaded function name is required to have the
7727 form of a pointer to member as described in 5.3.1.
7729 If more than one function is selected, any template functions in
7730 the set are eliminated if the set also contains a non-template
7731 function, and any given template function is eliminated if the
7732 set contains a second template function that is more specialized
7733 than the first according to the partial ordering rules 14.5.5.2.
7734 After such eliminations, if any, there shall remain exactly one
7735 selected function. */
7738 /* We store the matches in a TREE_LIST rooted here. The functions
7739 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7740 interoperability with most_specialized_instantiation. */
7742 tree fn;
7743 tree target_fn_type;
7745 /* By the time we get here, we should be seeing only real
7746 pointer-to-member types, not the internal POINTER_TYPE to
7747 METHOD_TYPE representation. */
7753 /* Check that the TARGET_TYPE is reasonable. */
7758 /* This is OK, too. */
7761 /* This is OK, too. This comes from a conversion to reference
7762 type. */
7764 else
7765 {
7771 }
7773 /* Non-member functions and static member functions match targets of type
7774 "pointer-to-function" or "reference-to-function." Nonstatic member
7775 functions match targets of type "pointer-to-member-function;" the
7776 function type of the pointer to member is used to select the member
7777 function from the set of overloaded member functions.
7779 So figure out the FUNCTION_TYPE that we want to match against. */
7782 /* If we can find a non-template function that matches, we can just
7783 use it. There's no point in generating template instantiations
7784 if we're just going to throw them out anyhow. But, of course, we
7785 can only do this when we don't *need* a template function. */
7788 {
7792 /* We're not looking for templates just yet. */
7796 /* We're looking for a non-static member, and this isn't
7797 one, or vice versa. */
7800 /* In C++17 we need the noexcept-qualifier to compare types. */
7805 /* See if there's a match. */
7810 }
7812 /* Now, if we've already got a match (or matches), there's no need
7813 to proceed to the template functions. But, if we don't have a
7814 match we need to look at them, too. */
7816 {
7817 tree target_arg_types;
7818 tree target_ret_type;
7821 tree arg;
7835 {
7837 tree instantiation;
7838 tree targs;
7841 /* We're only looking for templates. */
7846 /* We're not looking for a non-static member, and this is
7847 one, or vice versa. */
7852 /* If the template has a deduced return type, don't expose it to
7853 template argument deduction. */
7857 /* Try to do argument deduction. */
7864 /* Instantiation failed. */
7867 /* Constraints must be satisfied. This is done before
7868 return type deduction since that instantiates the
7869 function. */
7873 /* And now force instantiation to do return type deduction. */
7875 {
7881 }
7883 /* In C++17 we need the noexcept-qualifier to compare types. */
7887 /* See if there's a match. */
7892 }
7894 /* Now, remove all but the most specialized of the matches. */
7896 {
7901 NULL_TREE,
7902 NULL_TREE);
7903 }
7904 }
7906 /* Now we should have exactly one function in MATCHES. */
7908 {
7909 /* There were *no* matches. */
7911 {
7916 }
7918 }
7920 {
7921 /* There were too many matches. First check if they're all
7922 the same function. */
7927 /* For multi-versioned functions, more than one match is just fine and
7928 decls_match will return false as they are different. */
7936 {
7938 {
7942 /* Since print_candidates expects the functions in the
7943 TREE_VALUE slot, we flip them here. */
7948 }
7951 }
7952 }
7954 /* Good, exactly one match. Now, convert it to the correct type. */
7959 {
7967 {
7970 }
7971 }
7973 /* If a pointer to a function that is multi-versioned is requested, the
7974 pointer to the dispatcher function is returned instead. This works
7975 well because indirectly calling the function will dispatch the right
7976 function version at run-time. */
7978 {
7982 /* Mark all the versions corresponding to the dispatcher as used. */
7985 }
7987 /* If we're doing overload resolution purely for the purpose of
7988 determining conversion sequences, we should not consider the
7989 function used. If this conversion sequence is selected, the
7990 function will be marked as used at this point. */
7992 {
7993 /* Make =delete work with SFINAE. */
7998 }
8000 /* We could not check access to member functions when this
8001 expression was originally created since we did not know at that
8002 time to which function the expression referred. */
8004 {
8007 }
8011 else
8012 {
8013 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
8014 will mark the function as addressed, but here we must do it
8015 explicitly. */
8019 }
8020 }
8022 /* This function will instantiate the type of the expression given in
8023 RHS to match the type of LHSTYPE. If errors exist, then return
8024 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
8025 we complain on errors. If we are not complaining, never modify rhs,
8026 as overload resolution wants to try many possible instantiations, in
8027 the hope that at least one will work.
8029 For non-recursive calls, LHSTYPE should be a function, pointer to
8030 function, or a pointer to member function. */
8032 tree
8034 {
8041 {
8045 }
8048 {
8057 /* Microsoft allows `A::f' to be resolved to a
8058 pointer-to-member. */
8059 ;
8060 else
8061 {
8066 }
8067 }
8070 {
8073 }
8075 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
8076 deduce any type information. */
8078 {
8082 }
8084 /* If we instantiate a template, and it is a A ?: C expression
8085 with omitted B, look through the SAVE_EXPR. */
8089 /* There are only a few kinds of expressions that may have a type
8090 dependent on overload resolution. */
8096 /* This should really only be used when attempting to distinguish
8097 what sort of a pointer to function we have. For now, any
8098 arithmetic operation which is not supported on pointers
8099 is rejected as an error. */
8102 {
8104 {
8110 /* Do not lose object's side effects. */
8114 }
8121 /* This can happen if we are forming a pointer-to-member for a
8122 member template. */
8125 /* Fall through. */
8128 {
8132 return
8136 }
8140 return
8144 access_path);
8147 {
8152 }
8159 }
8161 }
8162 \f
8163 /* Return the name of the virtual function pointer field
8164 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8165 this may have to look back through base types to find the
8166 ultimate field name. (For single inheritance, these could
8167 all be the same name. Who knows for multiple inheritance). */
8169 static tree
8171 {
8177 {
8183 }
8191 }
8193 void
8195 {
8202 {
8207 }
8208 }
8210 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8211 according to [class]:
8212 The class-name is also inserted
8213 into the scope of the class itself. For purposes of access checking,
8214 the inserted class name is treated as if it were a public member name. */
8216 void
8218 {
8235 }
8237 /* Returns 1 if TYPE contains only padding bytes. */
8239 int
8241 {
8249 }
8251 /* Returns true if TYPE contains no actual data, just various
8252 possible combinations of empty classes and possibly a vptr. */
8254 bool
8256 {
8258 {
8259 tree field;
8260 tree binfo;
8261 tree base_binfo;
8264 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8265 out, but we'd like to be able to check this before then. */
8276 /* An unnamed bit-field is not a data member. */
8281 }
8286 }
8288 /* Note that NAME was looked up while the current class was being
8289 defined and that the result of that lookup was DECL. */
8291 void
8293 {
8294 splay_tree names_used;
8296 /* If we're not defining a class, there's nothing to do. */
8302 /* If there's already a binding for this NAME, then we don't have
8303 anything to worry about. */
8316 }
8318 /* Note that NAME was declared (as DECL) in the current class. Check
8319 to see that the declaration is valid. */
8321 void
8323 {
8324 splay_tree names_used;
8325 splay_tree_node n;
8327 /* Look to see if we ever used this name. */
8328 names_used
8332 /* The C language allows members to be declared with a type of the same
8333 name, and the C++ standard says this diagnostic is not required. So
8334 allow it in extern "C" blocks unless predantic is specified.
8335 Allow it in all cases if -ms-extensions is specified. */
8341 {
8342 /* [basic.scope.class]
8344 A name N used in a class S shall refer to the same declaration
8345 in its context and when re-evaluated in the completed scope of
8346 S. */
8351 }
8352 }
8354 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8355 Secondary vtables are merged with primary vtables; this function
8356 will return the VAR_DECL for the primary vtable. */
8358 tree
8360 {
8361 tree decl;
8365 {
8368 }
8372 }
8375 /* Returns the binfo for the primary base of BINFO. If the resulting
8376 BINFO is a virtual base, and it is inherited elsewhere in the
8377 hierarchy, then the returned binfo might not be the primary base of
8378 BINFO in the complete object. Check BINFO_PRIMARY_P or
8379 BINFO_LOST_PRIMARY_P to be sure. */
8381 static tree
8383 {
8384 tree primary_base;
8391 }
8393 /* As above, but iterate until we reach the binfo that actually provides the
8394 vptr for BINFO. */
8396 static tree
8398 {
8402 {
8407 }
8409 }
8411 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8412 type. Note that the virtual inheritance might be above or below BINFO in
8413 the hierarchy. */
8415 bool
8417 {
8421 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8422 a morally virtual base. */
8425 }
8427 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8429 static int
8431 {
8435 }
8437 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8438 INDENT should be zero when called from the top level; it is
8439 incremented recursively. IGO indicates the next expected BINFO in
8440 inheritance graph ordering. */
8442 static tree
8444 dump_flags_t flags,
8445 tree binfo,
8446 tree igo,
8448 {
8450 tree base_binfo;
8458 {
8461 }
8476 {
8480 TFF_PLAIN_IDENTIFIER),
8482 }
8484 {
8487 }
8492 {
8496 {
8500 TFF_PLAIN_IDENTIFIER));
8501 }
8503 {
8507 TFF_PLAIN_IDENTIFIER));
8508 }
8510 {
8514 TFF_PLAIN_IDENTIFIER));
8515 }
8517 {
8521 TFF_PLAIN_IDENTIFIER));
8522 }
8526 }
8532 }
8534 /* Dump the BINFO hierarchy for T. */
8536 static void
8538 {
8550 }
8552 /* Debug interface to hierarchy dumping. */
8554 void
8556 {
8558 }
8560 static void
8562 {
8563 dump_flags_t flags;
8565 {
8568 }
8569 }
8571 static void
8573 {
8574 tree value;
8576 HOST_WIDE_INT elt;
8584 TFF_PLAIN_IDENTIFIER));
8591 }
8593 static void
8595 {
8596 dump_flags_t flags;
8603 {
8610 {
8615 }
8619 }
8622 }
8624 static void
8626 {
8627 dump_flags_t flags;
8634 {
8639 }
8642 }
8644 /* Dump a function or thunk and its thunkees. */
8646 static void
8648 {
8651 tree thunks;
8659 {
8669 else
8675 }
8679 }
8681 /* Dump the thunks for FN. */
8683 void
8685 {
8687 }
8689 /* Virtual function table initialization. */
8691 /* Create all the necessary vtables for T and its base classes. */
8693 static void
8695 {
8696 tree vbase;
8700 /* We lay out the primary and secondary vtables in one contiguous
8701 vtable. The primary vtable is first, followed by the non-virtual
8702 secondary vtables in inheritance graph order. */
8706 /* Then come the virtual bases, also in inheritance graph order. */
8708 {
8712 }
8716 }
8718 /* Initialize the vtable for BINFO with the INITS. */
8720 static void
8722 {
8723 tree decl;
8729 }
8731 /* Build the VTT (virtual table table) for T.
8732 A class requires a VTT if it has virtual bases.
8734 This holds
8735 1 - primary virtual pointer for complete object T
8736 2 - secondary VTTs for each direct non-virtual base of T which requires a
8737 VTT
8738 3 - secondary virtual pointers for each direct or indirect base of T which
8739 has virtual bases or is reachable via a virtual path from T.
8740 4 - secondary VTTs for each direct or indirect virtual base of T.
8742 Secondary VTTs look like complete object VTTs without part 4. */
8744 static void
8746 {
8747 tree type;
8748 tree vtt;
8749 tree index;
8752 /* Build up the initializers for the VTT. */
8757 /* If we didn't need a VTT, we're done. */
8761 /* Figure out the type of the VTT. */
8765 /* Now, build the VTT object itself. */
8768 /* Add the VTT to the vtables list. */
8773 }
8775 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8776 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8777 and CHAIN the vtable pointer for this binfo after construction is
8778 complete. VALUE can also be another BINFO, in which case we recurse. */
8780 static tree
8782 {
8783 tree vt;
8786 {
8792 else
8794 }
8797 }
8799 /* Data for secondary VTT initialization. */
8800 struct secondary_vptr_vtt_init_data
8801 {
8802 /* Is this the primary VTT? */
8805 /* Current index into the VTT. */
8806 tree index;
8808 /* Vector of initializers built up. */
8811 /* The type being constructed by this secondary VTT. */
8812 tree type_being_constructed;
8813 };
8815 /* Recursively build the VTT-initializer for BINFO (which is in the
8816 hierarchy dominated by T). INITS points to the end of the initializer
8817 list to date. INDEX is the VTT index where the next element will be
8818 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8819 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8820 for virtual bases of T. When it is not so, we build the constructor
8821 vtables for the BINFO-in-T variant. */
8823 static void
8826 {
8828 tree b;
8829 tree init;
8830 secondary_vptr_vtt_init_data data;
8833 /* We only need VTTs for subobjects with virtual bases. */
8837 /* We need to use a construction vtable if this is not the primary
8838 VTT. */
8840 {
8843 /* Record the offset in the VTT where this sub-VTT can be found. */
8845 }
8847 /* Add the address of the primary vtable for the complete object. */
8851 {
8854 }
8857 /* Recursively add the secondary VTTs for non-virtual bases. */
8862 /* Add secondary virtual pointers for all subobjects of BINFO with
8863 either virtual bases or reachable along a virtual path, except
8864 subobjects that are non-virtual primary bases. */
8874 /* data.inits might have grown as we added secondary virtual pointers.
8875 Make sure our caller knows about the new vector. */
8879 /* Add the secondary VTTs for virtual bases in inheritance graph
8880 order. */
8882 {
8887 }
8888 else
8889 /* Remove the ctor vtables we created. */
8891 }
8893 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8894 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8896 static tree
8898 {
8901 /* We don't care about bases that don't have vtables. */
8905 /* We're only interested in proper subobjects of the type being
8906 constructed. */
8910 /* We're only interested in bases with virtual bases or reachable
8911 via a virtual path from the type being constructed. */
8916 /* We're not interested in non-virtual primary bases. */
8920 /* Record the index where this secondary vptr can be found. */
8922 {
8927 {
8928 /* It's a primary virtual base, and this is not a
8929 construction vtable. Find the base this is primary of in
8930 the inheritance graph, and use that base's vtable
8931 now. */
8934 }
8935 }
8937 /* Add the initializer for the secondary vptr itself. */
8940 /* Advance the vtt index. */
8945 }
8947 /* Called from build_vtt_inits via dfs_walk. After building
8948 constructor vtables and generating the sub-vtt from them, we need
8949 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8950 binfo of the base whose sub vtt was generated. */
8952 static tree
8954 {
8958 /* If this class has no vtable, none of its bases do. */
8962 /* This might be a primary base, so have no vtable in this
8963 hierarchy. */
8966 /* If we scribbled the construction vtable vptr into BINFO, clear it
8967 out now. */
8973 }
8975 /* Build the construction vtable group for BINFO which is in the
8976 hierarchy dominated by T. */
8978 static void
8980 {
8981 tree type;
8982 tree vtbl;
8983 tree id;
8984 tree vbase;
8987 /* See if we've already created this construction vtable group. */
8993 /* Build a version of VTBL (with the wrong type) for use in
8994 constructing the addresses of secondary vtables in the
8995 construction vtable group. */
8998 /* Don't export construction vtables from shared libraries. Even on
8999 targets that don't support hidden visibility, this tells
9000 can_refer_decl_in_current_unit_p not to assume that it's safe to
9001 access from a different compilation unit (bz 54314). */
9009 /* Add the vtables for each of our virtual bases using the vbase in T
9010 binfo. */
9012 vbase;
9014 {
9015 tree b;
9022 }
9024 /* Figure out the type of the construction vtable. */
9031 /* Initialize the construction vtable. */
9035 }
9037 /* Add the vtbl initializers for BINFO (and its bases other than
9038 non-virtual primaries) to the list of INITS. BINFO is in the
9039 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
9040 the constructor the vtbl inits should be accumulated for. (If this
9041 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
9042 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
9043 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
9044 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
9045 but are not necessarily the same in terms of layout. */
9047 static void
9049 tree orig_binfo,
9050 tree rtti_binfo,
9051 tree vtbl,
9052 tree t,
9054 {
9056 tree base_binfo;
9061 /* If it doesn't have a vptr, we don't do anything. */
9065 /* If we're building a construction vtable, we're not interested in
9066 subobjects that don't require construction vtables. */
9072 /* Build the initializers for the BINFO-in-T vtable. */
9075 /* Walk the BINFO and its bases. We walk in preorder so that as we
9076 initialize each vtable we can figure out at what offset the
9077 secondary vtable lies from the primary vtable. We can't use
9078 dfs_walk here because we need to iterate through bases of BINFO
9079 and RTTI_BINFO simultaneously. */
9081 {
9082 /* Skip virtual bases. */
9088 inits);
9089 }
9090 }
9092 /* Called from accumulate_vtbl_inits. Adds the initializers for the
9093 BINFO vtable to L. */
9095 static void
9097 tree orig_binfo,
9098 tree rtti_binfo,
9099 tree orig_vtbl,
9100 tree t,
9102 {
9109 {
9110 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9111 primary virtual base. If it is not the same primary in
9112 the hierarchy of T, we'll need to generate a ctor vtable
9113 for it, to place at its location in T. If it is the same
9114 primary, we still need a VTT entry for the vtable, but it
9115 should point to the ctor vtable for the base it is a
9116 primary for within the sub-hierarchy of RTTI_BINFO.
9118 There are three possible cases:
9120 1) We are in the same place.
9121 2) We are a primary base within a lost primary virtual base of
9122 RTTI_BINFO.
9123 3) We are primary to something not a base of RTTI_BINFO. */
9125 tree b;
9128 /* First, look through the bases we are primary to for RTTI_BINFO
9129 or a virtual base. */
9132 {
9137 }
9138 /* If we run out of primary links, keep looking down our
9139 inheritance chain; we might be an indirect primary. */
9143 found:
9145 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9146 base B and it is a base of RTTI_BINFO, this is case 2. In
9147 either case, we share our vtable with LAST, i.e. the
9148 derived-most base within B of which we are a primary. */
9151 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9152 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9153 binfo_ctor_vtable after everything's been set up. */
9156 /* Otherwise, this is case 3 and we get our own. */
9157 }
9164 {
9165 tree index;
9168 /* Add the initializer for this vtable. */
9172 /* Figure out the position to which the VPTR should point. */
9178 }
9181 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9182 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9183 straighten this out. */
9186 /* Throw away any unneeded intializers. */
9188 else
9189 /* For an ordinary vtable, set BINFO_VTABLE. */
9191 }
9196 /* Construct the initializer for BINFO's virtual function table. BINFO
9197 is part of the hierarchy dominated by T. If we're building a
9198 construction vtable, the ORIG_BINFO is the binfo we should use to
9199 find the actual function pointers to put in the vtable - but they
9200 can be overridden on the path to most-derived in the graph that
9201 ORIG_BINFO belongs. Otherwise,
9202 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9203 BINFO that should be indicated by the RTTI information in the
9204 vtable; it will be a base class of T, rather than T itself, if we
9205 are building a construction vtable.
9207 The value returned is a TREE_LIST suitable for wrapping in a
9208 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9209 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9210 number of non-function entries in the vtable.
9212 It might seem that this function should never be called with a
9213 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9214 base is always subsumed by a derived class vtable. However, when
9215 we are building construction vtables, we do build vtables for
9216 primary bases; we need these while the primary base is being
9217 constructed. */
9219 static void
9221 tree orig_binfo,
9222 tree t,
9223 tree rtti_binfo,
9226 {
9227 tree v;
9228 vtbl_init_data vid;
9230 tree vbinfo;
9234 /* Initialize VID. */
9242 /* The first vbase or vcall offset is at index -3 in the vtable. */
9245 /* Add entries to the vtable for RTTI. */
9248 /* Create an array for keeping track of the functions we've
9249 processed. When we see multiple functions with the same
9250 signature, we share the vcall offsets. */
9252 /* Add the vcall and vbase offset entries. */
9255 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9256 build_vbase_offset_vtbl_entries. */
9261 /* If the target requires padding between data entries, add that now. */
9263 {
9268 /* Move data entries into their new positions and add padding
9269 after the new positions. Iterate backwards so we don't
9270 overwrite entries that we would need to process later. */
9273 ix--)
9274 {
9282 {
9286 null_pointer_node);
9287 }
9288 }
9289 }
9294 /* The initializers for virtual functions were built up in reverse
9295 order. Straighten them out and add them to the running list in one
9296 step. */
9305 /* Go through all the ordinary virtual functions, building up
9306 initializers. */
9308 {
9309 tree delta;
9310 tree vcall_index;
9317 {
9321 {
9324 }
9326 }
9328 /* If the only definition of this function signature along our
9329 primary base chain is from a lost primary, this vtable slot will
9330 never be used, so just zero it out. This is important to avoid
9331 requiring extra thunks which cannot be generated with the function.
9333 We first check this in update_vtable_entry_for_fn, so we handle
9334 restored primary bases properly; we also need to do it here so we
9335 zero out unused slots in ctor vtables, rather than filling them
9336 with erroneous values (though harmless, apart from relocation
9337 costs). */
9342 {
9343 /* Pull the offset for `this', and the function to call, out of
9344 the list. */
9351 /* You can't call an abstract virtual function; it's abstract.
9352 So, we replace these functions with __pure_virtual. */
9354 {
9357 {
9359 abort_fndecl_addr
9363 }
9364 }
9365 /* Likewise for deleted virtuals. */
9367 {
9369 {
9373 dvirt_fn = push_library_fn
9377 }
9382 }
9383 else
9384 {
9386 {
9391 }
9392 /* Take the address of the function, considering it to be of an
9393 appropriate generic type. */
9397 /* Don't refer to a virtual destructor from a constructor
9398 vtable or a vtable for an abstract class, since destroying
9399 an object under construction is undefined behavior and we
9400 don't want it to be considered a candidate for speculative
9401 devirtualization. But do create the thunk for ABI
9402 compliance. */
9407 }
9408 }
9410 /* And add it to the chain of initializers. */
9412 {
9417 else
9419 {
9425 }
9426 }
9427 else
9429 }
9430 }
9432 /* Adds to vid->inits the initializers for the vbase and vcall
9433 offsets in BINFO, which is in the hierarchy dominated by T. */
9435 static void
9437 {
9438 tree b;
9440 /* If this is a derived class, we must first create entries
9441 corresponding to the primary base class. */
9446 /* Add the vbase entries for this base. */
9448 /* Add the vcall entries for this base. */
9450 }
9452 /* Returns the initializers for the vbase offset entries in the vtable
9453 for BINFO (which is part of the class hierarchy dominated by T), in
9454 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9455 where the next vbase offset will go. */
9457 static void
9459 {
9460 tree vbase;
9461 tree t;
9462 tree non_primary_binfo;
9464 /* If there are no virtual baseclasses, then there is nothing to
9465 do. */
9471 /* We might be a primary base class. Go up the inheritance hierarchy
9472 until we find the most derived class of which we are a primary base:
9473 it is the offset of that which we need to use. */
9476 {
9477 tree b;
9479 /* If we have reached a virtual base, then it must be a primary
9480 base (possibly multi-level) of vid->binfo, or we wouldn't
9481 have called build_vcall_and_vbase_vtbl_entries for it. But it
9482 might be a lost primary, so just skip down to vid->binfo. */
9484 {
9487 }
9493 }
9495 /* Go through the virtual bases, adding the offsets. */
9497 vbase;
9499 {
9500 tree b;
9501 tree delta;
9506 /* Find the instance of this virtual base in the complete
9507 object. */
9510 /* If we've already got an offset for this virtual base, we
9511 don't need another one. */
9516 /* Figure out where we can find this vbase offset. */
9525 /* The vbase offset had better be the same. */
9528 /* The next vbase will come at a more negative offset. */
9532 /* The initializer is the delta from BINFO to this virtual base.
9533 The vbase offsets go in reverse inheritance-graph order, and
9534 we are walking in inheritance graph order so these end up in
9535 the right order. */
9542 }
9543 }
9545 /* Adds the initializers for the vcall offset entries in the vtable
9546 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9547 to VID->INITS. */
9549 static void
9551 {
9552 /* We only need these entries if this base is a virtual base. We
9553 compute the indices -- but do not add to the vtable -- when
9554 building the main vtable for a class. */
9557 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9558 correspond to VID->DERIVED), we are building a primary
9559 construction virtual table. Since this is a primary
9560 virtual table, we do not need the vcall offsets for
9561 BINFO. */
9563 {
9564 /* We need a vcall offset for each of the virtual functions in this
9565 vtable. For example:
9567 class A { virtual void f (); };
9568 class B1 : virtual public A { virtual void f (); };
9569 class B2 : virtual public A { virtual void f (); };
9570 class C: public B1, public B2 { virtual void f (); };
9572 A C object has a primary base of B1, which has a primary base of A. A
9573 C also has a secondary base of B2, which no longer has a primary base
9574 of A. So the B2-in-C construction vtable needs a secondary vtable for
9575 A, which will adjust the A* to a B2* to call f. We have no way of
9576 knowing what (or even whether) this offset will be when we define B2,
9577 so we store this "vcall offset" in the A sub-vtable and look it up in
9578 a "virtual thunk" for B2::f.
9580 We need entries for all the functions in our primary vtable and
9581 in our non-virtual bases' secondary vtables. */
9583 /* If we are just computing the vcall indices -- but do not need
9584 the actual entries -- not that. */
9587 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9589 }
9590 }
9592 /* Build vcall offsets, starting with those for BINFO. */
9594 static void
9596 {
9598 tree primary_binfo;
9599 tree base_binfo;
9601 /* Don't walk into virtual bases -- except, of course, for the
9602 virtual base for which we are building vcall offsets. Any
9603 primary virtual base will have already had its offsets generated
9604 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9608 /* If BINFO has a primary base, process it first. */
9613 /* Add BINFO itself to the list. */
9616 /* Scan the non-primary bases of BINFO. */
9620 }
9622 /* Called from build_vcall_offset_vtbl_entries_r. */
9624 static void
9626 {
9627 /* Make entries for the rest of the virtuals. */
9628 tree orig_fn;
9630 /* The ABI requires that the methods be processed in declaration
9631 order. */
9633 orig_fn;
9637 }
9639 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9641 static void
9643 {
9645 tree vcall_offset;
9646 tree derived_entry;
9648 /* If there is already an entry for a function with the same
9649 signature as FN, then we do not need a second vcall offset.
9650 Check the list of functions already present in the derived
9651 class vtable. */
9653 {
9655 /* We only use one vcall offset for virtual destructors,
9656 even though there are two virtual table entries. */
9660 }
9662 /* If we are building these vcall offsets as part of building
9663 the vtable for the most derived class, remember the vcall
9664 offset. */
9666 {
9669 }
9671 /* The next vcall offset will be found at a more negative
9672 offset. */
9676 /* Keep track of this function. */
9680 {
9681 tree base;
9682 tree fn;
9684 /* Find the overriding function. */
9688 else
9689 {
9692 /* The vbase we're working on is a primary base of
9693 vid->binfo. But it might be a lost primary, so its
9694 BINFO_OFFSET might be wrong, so we just use the
9695 BINFO_OFFSET from vid->binfo. */
9701 vcall_offset);
9702 }
9703 /* Add the initializer to the vtable. */
9705 }
9706 }
9708 /* Return vtbl initializers for the RTTI entries corresponding to the
9709 BINFO's vtable. The RTTI entries should indicate the object given
9710 by VID->rtti_binfo. */
9712 static void
9714 {
9715 tree b;
9716 tree t;
9717 tree offset;
9718 tree decl;
9719 tree init;
9723 /* To find the complete object, we will first convert to our most
9724 primary base, and then add the offset in the vtbl to that value. */
9729 /* The second entry is the address of the typeinfo object. */
9732 else
9735 /* Convert the declaration to a type that can be stored in the
9736 vtable. */
9740 /* Add the offset-to-top entry. It comes earlier in the vtable than
9741 the typeinfo entry. Convert the offset to look like a
9742 function pointer, so that we can put it in the vtable. */
9745 }
9747 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9748 accessibility. */
9750 bool
9752 {
9755 }
9757 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9759 bool
9761 {
9765 }
9767 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9768 class between them, if any. */
9770 tree
9772 {
9784 {
9787 }
9791 }