| blob | b705d6bba596760d5b5f27e9ecb27ae2e30a9f64 |
1 /* Functions related to building classes and their related objects.
2 Copyright (C) 1987-2016 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. */
40 /* The number of nested classes being processed. If we are not in the
41 scope of any class, this is zero. */
45 /* In order to deal with nested classes, we keep a stack of classes.
46 The topmost entry is the innermost class, and is the entry at index
47 CURRENT_CLASS_DEPTH */
50 /* The name of the class. */
51 tree name;
53 /* The _TYPE node for the class. */
54 tree type;
56 /* The access specifier pending for new declarations in the scope of
57 this class. */
58 tree access;
60 /* If were defining TYPE, the names used in this class. */
61 splay_tree names_used;
63 /* Nonzero if this class is no longer open, because of a call to
64 push_to_top_level. */
68 struct vtbl_init_data
69 {
70 /* The base for which we're building initializers. */
71 tree binfo;
72 /* The type of the most-derived type. */
73 tree derived;
74 /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
75 unless ctor_vtbl_p is true. */
76 tree rtti_binfo;
77 /* The negative-index vtable initializers built up so far. These
78 are in order from least negative index to most negative index. */
80 /* The binfo for the virtual base for which we're building
81 vcall offset initializers. */
82 tree vbase;
83 /* The functions in vbase for which we have already provided vcall
84 offsets. */
86 /* The vtable index of the next vcall or vbase offset. */
87 tree index;
88 /* Nonzero if we are building the initializer for the primary
89 vtable. */
91 /* Nonzero if we are building the initializer for a construction
92 vtable. */
94 /* True when adding vcall offset entries to the vtable. False when
95 merely computing the indices. */
97 };
99 /* The type of a function passed to walk_subobject_offsets. */
102 /* The stack itself. This is a dynamically resized array. The
103 number of elements allocated is CURRENT_CLASS_STACK_SIZE. */
107 /* The size of the largest empty class seen in this translation unit. */
110 /* An array of all local classes present in this translation unit, in
111 declaration order. */
150 /* Used by find_flexarrays and related. */
200 tree *);
210 splay_tree_key k2);
218 /* Variables shared between class.c and call.c. */
228 /* Convert to or from a base subobject. EXPR is an expression of type
229 `A' or `A*', an expression of type `B' or `B*' is returned. To
230 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
231 the B base instance within A. To convert base A to derived B, CODE
232 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
233 In this latter case, A must not be a morally virtual base of B.
234 NONNULL is true if EXPR is known to be non-NULL (this is only
235 needed when EXPR is of pointer type). CV qualifiers are preserved
236 from EXPR. */
238 tree
240 tree expr,
241 tree binfo,
243 tsubst_flags_t complain)
244 {
247 tree probe;
248 tree offset;
249 tree target_type;
251 tree ptr_target_type;
262 {
268 }
276 {
277 /* This can happen when adjust_result_of_qualified_name_lookup can't
278 find a unique base binfo in a call to a member function. We
279 couldn't give the diagnostic then since we might have been calling
280 a static member function, so we do it now. */
282 {
286 }
288 }
295 /* Nothing to do. */
299 {
301 {
303 {
306 "pointer to derived class %qT because the base is "
308 else
312 }
313 else
314 {
320 else
324 }
325 }
327 }
330 {
332 /* This must happen before the call to save_expr. */
334 }
335 else
341 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
342 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
343 expression returned matches the input. */
344 target_type = cp_build_qualified_type
348 /* Do we need to look in the vtable for the real offset? */
351 /* Don't bother with the calculations inside sizeof; they'll ICE if the
352 source type is incomplete and the pointer value doesn't matter. In a
353 template (even in instantiate_non_dependent_expr), we don't have vtables
354 set up properly yet, and the value doesn't matter there either; we're
355 just interested in the result of overload resolution. */
358 {
361 }
363 /* If we're in an NSDMI, we don't have the full constructor context yet
364 that we need for converting to a virtual base, so just build a stub
365 CONVERT_EXPR and expand it later in bot_replace. */
368 {
372 }
374 /* Do we need to check for a null pointer? */
376 {
377 /* If we know the conversion will not actually change the value
378 of EXPR, then we can avoid testing the expression for NULL.
379 We have to avoid generating a COMPONENT_REF for a base class
380 field, because other parts of the compiler know that such
381 expressions are always non-NULL. */
385 }
387 /* Protect against multiple evaluation if necessary. */
391 /* Now that we've saved expr, build the real null test. */
393 {
397 }
399 /* If this is a simple base reference, express it as a COMPONENT_REF. */
401 /* We don't build base fields for empty bases, and they aren't very
402 interesting to the optimizers anyway. */
404 {
413 }
416 {
417 /* Going via virtual base V_BINFO. We need the static offset
418 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
419 V_BINFO. That offset is an entry in D_BINFO's vtable. */
420 tree v_offset;
423 {
424 /* In a base member initializer, we cannot rely on the
425 vtable being set up. We have to indirect via the
426 vtt_parm. */
427 tree t;
433 }
434 else
435 {
438 {
443 }
445 complain),
447 }
455 v_offset);
467 /* Negative fixed_type_p means this is a constructor or destructor;
468 virtual base layout is fixed in in-charge [cd]tors, but not in
469 base [cd]tors. */
473 v_offset,
476 else
478 }
486 {
491 }
492 else
495 indout:
497 {
501 }
503 out:
509 }
511 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
512 Perform a derived-to-base conversion by recursively building up a
513 sequence of COMPONENT_REFs to the appropriate base fields. */
515 static tree
517 {
520 tree field;
523 {
524 tree temp;
528 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
529 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
530 an lvalue in the front end; only _DECLs and _REFs are lvalues
531 in the back end. */
537 }
539 /* Recurse. */
544 /* Is this the base field created by build_base_field? */
548 /* If we're looking for a field in the most-derived class,
549 also check the field offset; we can have two base fields
550 of the same type if one is an indirect virtual base and one
551 is a direct non-virtual base. */
555 {
556 /* We don't use build_class_member_access_expr here, as that
557 has unnecessary checks, and more importantly results in
558 recursive calls to dfs_walk_once. */
564 /* Mark the expression const or volatile, as appropriate.
565 Even though we've dealt with the type above, we still have
566 to mark the expression itself. */
573 }
575 /* Didn't find the base field?!? */
577 }
579 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
580 type is a class type or a pointer to a class type. In the former
581 case, TYPE is also a class type; in the latter it is another
582 pointer type. If CHECK_ACCESS is true, an error message is emitted
583 if TYPE is inaccessible. If OBJECT has pointer type, the value is
584 assumed to be non-NULL. */
586 tree
588 tsubst_flags_t complain)
589 {
590 tree binfo;
591 tree object_type;
594 {
597 }
598 else
607 }
609 /* EXPR is an expression with unqualified class type. BASE is a base
610 binfo of that class type. Returns EXPR, converted to the BASE
611 type. This function assumes that EXPR is the most derived class;
612 therefore virtual bases can be found at their static offsets. */
614 tree
616 {
617 tree expr_type;
621 {
622 /* If this is a non-empty base, use a COMPONENT_REF. */
626 /* We use fold_build2 and fold_convert below to simplify the trees
627 provided to the optimizers. It is not safe to call these functions
628 when processing a template because they do not handle C++-specific
629 trees. */
637 }
640 }
642 \f
643 tree
645 {
649 /* Can happen in case of duplicate base types (c++/59082). */
653 /* First, convert to the requested type. */
658 /* Second, the requested type may not be the owner of its own vptr.
659 If not, convert to the base class that owns it. We cannot use
660 convert_to_base here, because VCONTEXT may appear more than once
661 in the inheritance hierarchy of TYPE, and thus direct conversion
662 between the types may be ambiguous. Following the path back up
663 one step at a time via primary bases avoids the problem. */
667 {
670 }
673 }
675 /* Given an object INSTANCE, return an expression which yields the
676 vtable element corresponding to INDEX. There are many special
677 cases for INSTANCE which we take care of here, mainly to avoid
678 creating extra tree nodes when we don't have to. */
680 static tree
682 {
683 tree aref;
686 /* Try to figure out what a reference refers to, and
687 access its virtual function table directly. */
695 {
700 }
709 }
711 tree
713 {
717 }
719 /* Given a stable object pointer INSTANCE_PTR, return an expression which
720 yields a function pointer corresponding to vtable element INDEX. */
722 tree
724 {
725 tree aref;
728 tf_warning_or_error),
729 idx);
731 /* When using function descriptors, the address of the
732 vtable entry is treated as a function pointer. */
737 /* Remember this as a method reference, for later devirtualization. */
741 }
743 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
744 for the given TYPE. */
746 static tree
748 {
750 }
752 /* DECL is an entity associated with TYPE, like a virtual table or an
753 implicitly generated constructor. Determine whether or not DECL
754 should have external or internal linkage at the object file
755 level. This routine does not deal with COMDAT linkage and other
756 similar complexities; it simply sets TREE_PUBLIC if it possible for
757 entities in other translation units to contain copies of DECL, in
758 the abstract. */
760 void
762 {
765 }
767 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
768 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
769 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
771 static tree
773 {
774 tree decl;
777 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
778 now to avoid confusion in mangle_decl. */
789 /* The vtable has not been defined -- yet. */
793 /* Mark the VAR_DECL node representing the vtable itself as a
794 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
795 is rather important that such things be ignored because any
796 effort to actually generate DWARF for them will run into
797 trouble when/if we encounter code like:
799 #pragma interface
800 struct S { virtual void member (); };
802 because the artificial declaration of the vtable itself (as
803 manufactured by the g++ front end) will say that the vtable is
804 a static member of `S' but only *after* the debug output for
805 the definition of `S' has already been output. This causes
806 grief because the DWARF entry for the definition of the vtable
807 will try to refer back to an earlier *declaration* of the
808 vtable as a static member of `S' and there won't be one. We
809 might be able to arrange to have the "vtable static member"
810 attached to the member list for `S' before the debug info for
811 `S' get written (which would solve the problem) but that would
812 require more intrusive changes to the g++ front end. */
816 }
818 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
819 or even complete. If this does not exist, create it. If COMPLETE is
820 nonzero, then complete the definition of it -- that will render it
821 impossible to actually build the vtable, but is useful to get at those
822 which are known to exist in the runtime. */
824 tree
826 {
827 tree decl;
836 {
839 }
842 }
844 /* Build the primary virtual function table for TYPE. If BINFO is
845 non-NULL, build the vtable starting with the initial approximation
846 that it is the same as the one which is the head of the association
847 list. Returns a nonzero value if a new vtable is actually
848 created. */
850 static int
852 {
853 tree decl;
854 tree virtuals;
859 {
861 /* We have already created a vtable for this base, so there's
862 no need to do it again. */
869 }
870 else
871 {
874 }
877 {
880 }
882 /* Initialize the association list for this type, based
883 on our first approximation. */
888 }
890 /* Give BINFO a new virtual function table which is initialized
891 with a skeleton-copy of its original initialization. The only
892 entry that changes is the `delta' entry, so we can really
893 share a lot of structure.
895 FOR_TYPE is the most derived type which caused this table to
896 be needed.
898 Returns nonzero if we haven't met BINFO before.
900 The order in which vtables are built (by calling this function) for
901 an object must remain the same, otherwise a binary incompatibility
902 can result. */
904 static int
906 {
908 /* We already created a vtable for this base. There's no need to
909 do it again. */
912 /* Remember that we've created a vtable for this BINFO, so that we
913 don't try to do so again. */
916 /* Make fresh virtual list, so we can smash it later. */
919 /* Secondary vtables are laid out as part of the same structure as
920 the primary vtable. */
923 }
925 /* Create a new vtable for BINFO which is the hierarchy dominated by
926 T. Return nonzero if we actually created a new vtable. */
928 static int
930 {
932 /* In this case, it is *type*'s vtable we are modifying. We start
933 with the approximation that its vtable is that of the
934 immediate base class. */
936 else
937 /* This is our very own copy of `basetype' to play with. Later,
938 we will fill in all the virtual functions that override the
939 virtual functions in these base classes which are not defined
940 by the current type. */
942 }
944 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
945 (which is in the hierarchy dominated by T) list FNDECL as its
946 BV_FN. DELTA is the required constant adjustment from the `this'
947 pointer where the vtable entry appears to the `this' required when
948 the function is actually called. */
950 static void
952 tree binfo,
953 tree fndecl,
954 tree delta,
956 {
957 tree v;
963 {
964 /* We need a new vtable for BINFO. */
966 {
967 /* If we really did make a new vtable, we also made a copy
968 of the BINFO_VIRTUALS list. Now, we have to find the
969 corresponding entry in that list. */
974 }
979 }
980 }
982 \f
983 /* Add method METHOD to class TYPE. If USING_DECL is non-null, it is
984 the USING_DECL naming METHOD. Returns true if the method could be
985 added to the method vec. */
987 bool
989 {
991 tree overload;
997 tree current_fns;
998 tree fns;
1011 {
1012 /* Make a new method vector. We start with 8 entries. We must
1013 allocate at least two (for constructors and destructors), and
1014 we're going to end up with an assignment operator at some
1015 point as well. */
1017 /* Create slots for constructors and destructors. */
1021 }
1023 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1026 /* Constructors and destructors go in special slots. */
1030 {
1034 {
1040 type);
1041 }
1042 }
1043 else
1044 {
1045 tree m;
1048 /* See if we already have an entry with this name. */
1052 {
1055 {
1060 }
1064 {
1067 }
1072 }
1073 }
1076 /* Check to see if we've already got this method. */
1078 {
1080 tree fn_type;
1081 tree method_type;
1082 tree parms1;
1083 tree parms2;
1088 /* [over.load] Member function declarations with the
1089 same name and the same parameter types cannot be
1090 overloaded if any of them is a static member
1091 function declaration.
1093 [over.load] Member function declarations with the same name and
1094 the same parameter-type-list as well as member function template
1095 declarations with the same name, the same parameter-type-list, and
1096 the same template parameter lists cannot be overloaded if any of
1097 them, but not all, have a ref-qualifier.
1099 [namespace.udecl] When a using-declaration brings names
1100 from a base class into a derived class scope, member
1101 functions in the derived class override and/or hide member
1102 functions with the same name and parameter types in a base
1103 class (rather than conflicting). */
1109 /* Compare the quals on the 'this' parm. Don't compare
1110 the whole types, as used functions are treated as
1111 coming from the using class in overload resolution. */
1114 /* Either both or neither need to be ref-qualified for
1115 differing quals to allow overloading. */
1122 /* For templates, the return type and template parameters
1123 must be identical. */
1141 {
1142 /* For function versions, their parms and types match
1143 but they are not duplicates. Record function versions
1144 as and when they are found. extern "C" functions are
1145 not treated as versions. */
1151 {
1152 /* Mark functions as versions if necessary. Modify the mangled
1153 decl name if necessary. */
1155 {
1159 }
1161 {
1165 }
1168 }
1170 {
1172 {
1179 }
1180 /* Otherwise defer to the other function. */
1182 }
1184 {
1186 /* Defer to the local function. */
1188 }
1189 else
1190 {
1193 }
1195 /* We don't call duplicate_decls here to merge the
1196 declarations because that will confuse things if the
1197 methods have inline definitions. In particular, we
1198 will crash while processing the definitions. */
1200 }
1201 }
1203 /* A class should never have more than one destructor. */
1207 /* Add the new binding. */
1209 {
1212 }
1213 else
1222 {
1225 /* We only expect to add few methods in the COMPLETE_P case, so
1226 just make room for one more method in that case. */
1229 else
1235 else
1237 }
1238 else
1239 /* Replace the current slot. */
1242 }
1244 /* Subroutines of finish_struct. */
1246 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1247 legit, otherwise return 0. */
1249 static int
1251 {
1252 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 /* Process the USING_DECL, which is a member of T. */
1290 static void
1292 {
1295 tree access
1300 tree old_value;
1305 tf_warning_or_error);
1307 {
1313 else
1315 }
1323 ;
1325 {
1327 /* It's OK to use functions from a base when there are functions with
1329 else
1330 {
1335 }
1336 }
1338 {
1342 }
1344 /* Make type T see field decl FDECL with access ACCESS. */
1347 {
1350 }
1351 else
1353 }
1354 \f
1355 /* Data structure for find_abi_tags_r, below. */
1357 struct abi_tag_data
1358 {
1362 };
1364 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1365 in the context of P. TAG can be either an identifier (the DECL_NAME of
1366 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1368 static void
1370 {
1372 {
1374 {
1375 /* We're collecting tags from template arguments or from
1376 the type of a variable or function return type. */
1379 /* Don't inherit this tag multiple times. */
1383 {
1384 /* Tags inherited from type template arguments are only used
1385 to avoid warnings. */
1388 }
1389 /* For functions and variables we want to warn, too. */
1390 }
1392 /* Otherwise we're diagnosing missing tags. */
1394 {
1399 }
1401 {
1405 }
1407 {
1412 }
1413 else
1414 {
1418 {
1422 }
1423 }
1424 }
1425 }
1427 /* Find all the ABI tags in the attribute list ATTR and either call
1428 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1430 static void
1432 {
1439 {
1444 else
1446 }
1447 }
1449 /* Find all the ABI tags on T and its enclosing scopes and either call
1450 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1452 static void
1454 {
1456 {
1457 tree attr;
1459 {
1462 }
1463 else
1464 {
1467 }
1469 }
1470 }
1472 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1473 types with ABI tags, add the corresponding identifiers to the VEC in
1474 *DATA and set IDENTIFIER_MARKED. */
1476 static tree
1478 {
1482 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1483 anyway, but let's make sure of it. */
1491 }
1493 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1494 IDENTIFIER_MARKED on its ABI tags. */
1496 static tree
1498 {
1502 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1503 anyway, but let's make sure of it. */
1511 }
1513 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1514 scopes. */
1516 static void
1518 {
1521 {
1524 {
1525 /* Template arguments are part of the signature. */
1528 {
1531 }
1532 }
1534 /* A function's parameter types are part of the signature, so
1535 we don't need to inherit any tags that are also in them. */
1540 }
1541 }
1543 /* Check that T has all the ABI tags that subobject SUBOB has, or
1544 warn if not. If T is a (variable or function) declaration, also
1545 add any missing tags. */
1547 static void
1549 {
1557 /* No need to worry about things local to this TU. */
1570 {
1574 else
1578 }
1581 }
1583 /* Check that DECL has all the ABI tags that are used in parts of its type
1584 that are not reflected in its mangled name. */
1586 void
1588 {
1594 }
1596 void
1598 {
1608 {
1611 {
1615 }
1616 }
1618 // If we found some tags on our template arguments, add them to our
1619 // abi_tag attribute.
1621 {
1625 else
1629 }
1632 }
1634 /* Return true, iff class T has a non-virtual destructor that is
1635 accessible from outside the class heirarchy (i.e. is public, or
1636 there's a suitable friend. */
1638 static bool
1640 {
1643 /* An implicitly declared destructor is always public. And,
1644 if it were virtual, we would have created it by now. */
1659 }
1661 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1662 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1663 properties of the bases. */
1665 static void
1669 {
1673 tree base_binfo;
1674 tree binfo;
1684 {
1693 /* If any base class is non-literal, so is the derived class. */
1697 /* If the base class doesn't have copy constructors or
1698 assignment operators that take const references, then the
1699 derived class cannot have such a member automatically
1700 generated. */
1709 /* A virtual base does not effect nearly emptiness. */
1710 ;
1712 {
1714 /* And if there is more than one nearly empty base, then the
1715 derived class is not nearly empty either. */
1717 else
1718 /* Remember we've seen one. */
1720 }
1722 /* If the base class is not empty or nearly empty, then this
1723 class cannot be nearly empty. */
1726 /* A lot of properties from the bases also apply to the derived
1727 class. */
1744 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1747 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1751 /* A standard-layout class is a class that:
1752 ...
1753 * has no non-standard-layout base classes, */
1756 {
1757 tree basefield;
1758 /* ...has no base classes of the same type as the first non-static
1759 data member... */
1761 && (same_type_ignoring_top_level_qualifiers_p
1764 else
1765 /* ...either has no non-static data members in the most-derived
1766 class and at most one base class with non-static data
1767 members, or has no base classes with non-static data
1768 members */
1772 {
1775 else
1778 }
1779 }
1781 /* Don't bother collecting tm attributes if transactional memory
1782 support is not enabled. */
1784 {
1788 }
1791 }
1793 /* If one of the base classes had TM attributes, and the current class
1794 doesn't define its own, then the current class inherits one. */
1796 {
1799 }
1800 }
1802 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1803 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1804 that have had a nearly-empty virtual primary base stolen by some
1805 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1806 T. */
1808 static void
1810 {
1814 tree base_binfo;
1816 /* Determine the primary bases of our bases. */
1819 {
1822 /* See if we're the non-virtual primary of our inheritance
1823 chain. */
1825 {
1832 /* We are the primary binfo. */
1834 }
1835 /* Determine if we have a virtual primary base, and mark it so.
1836 */
1838 {
1842 /* Someone already claimed this base. */
1844 else
1845 {
1846 tree delta;
1851 /* A virtual binfo might have been copied from within
1852 another hierarchy. As we're about to use it as a
1853 primary base, make sure the offsets match. */
1861 }
1862 }
1863 }
1865 /* First look for a dynamic direct non-virtual base. */
1867 {
1871 {
1874 }
1875 }
1877 /* A "nearly-empty" virtual base class can be the primary base
1878 class, if no non-virtual polymorphic base can be found. Look for
1879 a nearly-empty virtual dynamic base that is not already a primary
1880 base of something in the hierarchy. If there is no such base,
1881 just pick the first nearly-empty virtual base. */
1887 {
1889 {
1890 /* Found one that is not primary. */
1893 }
1895 /* Remember the first candidate. */
1897 }
1899 found:
1900 /* If we've got a primary base, use it. */
1902 {
1907 /* We are stealing a primary base. */
1911 {
1912 tree delta;
1915 /* A virtual binfo might have been copied from within
1916 another hierarchy. As we're about to use it as a primary
1917 base, make sure the offsets match. */
1922 }
1929 }
1930 }
1932 /* Update the variant types of T. */
1934 void
1936 {
1937 tree variants;
1943 variants;
1945 {
1946 /* These fields are in the _TYPE part of the node, not in
1947 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1957 /* Copy whatever these are holding today. */
1960 }
1961 }
1963 /* Early variant fixups: we apply attributes at the beginning of the class
1964 definition, and we need to fix up any variants that have already been
1965 made via elaborated-type-specifier so that check_qualified_type works. */
1967 void
1969 {
1970 tree variants;
1980 variants;
1982 {
1983 /* These are the two fields that check_qualified_type looks at and
1984 are affected by attributes. */
1989 else
1992 }
1993 }
1994 \f
1995 /* Set memoizing fields and bits of T (and its variants) for later
1996 use. */
1998 static void
2000 {
2001 /* Fix up variants (if any). */
2005 /* For a class w/o baseclasses, 'finish_struct' has set
2006 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
2007 Similarly for a class whose base classes do not have vtables.
2008 When neither of these is true, we might have removed abstract
2009 virtuals (by providing a definition), added some (by declaring
2010 new ones), or redeclared ones from a base class. We need to
2011 recalculate what's really an abstract virtual at this point (by
2012 looking in the vtables). */
2015 /* If this type has a copy constructor or a destructor, force its
2016 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
2017 nonzero. This will cause it to be passed by invisible reference
2018 and prevent it from being returned in a register. */
2021 {
2022 tree variants;
2025 {
2028 }
2029 }
2030 }
2032 /* Issue warnings about T having private constructors, but no friends,
2033 and so forth.
2035 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2036 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2037 non-private static member functions. */
2039 static void
2041 {
2044 tree fn;
2047 /* If the class has friends, those entities might create and
2048 access instances, so we should not warn. */
2051 /* We will have warned when the template was declared; there's
2052 no need to warn on every instantiation. */
2054 /* There's no reason to even consider warning about this
2055 class. */
2058 /* We only issue one warning, if more than one applies, because
2059 otherwise, on code like:
2061 class A {
2062 // Oops - forgot `public:'
2063 A();
2064 A(const A&);
2065 ~A();
2066 };
2068 we warn several times about essentially the same problem. */
2070 /* Check to see if all (non-constructor, non-destructor) member
2071 functions are private. (Since there are no friends or
2072 non-private statics, we can't ever call any of the private member
2073 functions.) */
2075 /* We're not interested in compiler-generated methods; they don't
2076 provide any way to call private members. */
2078 {
2080 {
2082 /* A non-private static member function is just like a
2083 friend; it can create and invoke private member
2084 functions, and be accessed without a class
2085 instance. */
2089 /* Keep searching for a static member function. */
2090 }
2093 }
2096 {
2097 /* There are no non-private methods, and there's at least one
2098 private member function that isn't a constructor or
2099 destructor. (If all the private members are
2100 constructors/destructors we want to use the code below that
2101 issues error messages specifically referring to
2102 constructors/destructors.) */
2108 {
2111 }
2113 {
2117 }
2118 }
2120 /* Even if some of the member functions are non-private, the class
2121 won't be useful for much if all the constructors or destructors
2122 are private: such an object can never be created or destroyed. */
2125 {
2128 t);
2130 }
2132 /* Warn about classes that have private constructors and no friends. */
2134 /* Implicitly generated constructors are always public. */
2137 {
2140 /* If a non-template class does not define a copy
2141 constructor, one is defined for it, enabling it to avoid
2142 this warning. For a template class, this does not
2143 happen, and so we would normally get a warning on:
2145 template <class T> class C { private: C(); };
2147 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2148 complete non-template or fully instantiated classes have this
2149 flag set. */
2152 else
2154 {
2156 /* Ideally, we wouldn't count copy constructors (or, in
2157 fact, any constructor that takes an argument of the
2158 class type as a parameter) because such things cannot
2159 be used to construct an instance of the class unless
2160 you already have one. But, for now at least, we're
2161 more generous. */
2163 {
2166 }
2167 }
2170 {
2173 t);
2175 }
2176 }
2177 }
2180 gt_pointer_operator new_value;
2184 /* Comparison function to compare two TYPE_METHOD_VEC entries by name. */
2186 static int
2188 {
2201 }
2203 /* This routine compares two fields like method_name_cmp but using the
2204 pointer operator in resort_field_decl_data. */
2206 static int
2208 {
2217 {
2224 }
2226 }
2228 /* Resort TYPE_METHOD_VEC because pointers have been reordered. */
2230 void
2233 gt_pointer_operator new_value,
2235 {
2239 tree fn;
2241 /* The type conversion ops have to live at the front of the vec, so we
2242 can't sort them. */
2250 {
2254 resort_method_name_cmp);
2255 }
2256 }
2258 /* Warn about duplicate methods in fn_fields.
2260 Sort methods that are not special (i.e., constructors, destructors,
2261 and type conversion operators) so that we can find them faster in
2262 search. */
2264 static void
2266 {
2267 tree fn_fields;
2277 /* Clear DECL_IN_AGGR_P for all functions. */
2282 /* Issue warnings about private constructors and such. If there are
2283 no methods, then some public defaults are generated. */
2286 /* The type conversion ops have to live at the front of the vec, so we
2287 can't sort them. */
2296 }
2298 /* Make BINFO's vtable have N entries, including RTTI entries,
2299 vbase and vcall offsets, etc. Set its type and call the back end
2300 to lay it out. */
2302 static void
2304 {
2305 tree atype;
2306 tree vtable;
2311 /* We may have to grow the vtable. */
2314 {
2318 }
2319 }
2321 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2322 have the same signature. */
2324 int
2326 {
2327 /* One destructor overrides another if they are the same kind of
2328 destructor. */
2332 /* But a non-destructor never overrides a destructor, nor vice
2333 versa, nor do different kinds of destructors override
2334 one-another. For example, a complete object destructor does not
2335 override a deleting destructor. */
2344 {
2352 }
2354 }
2356 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2357 subobject. */
2359 static bool
2361 {
2362 tree probe;
2365 {
2369 /* If we meet a virtual base, we can't follow the inheritance
2370 any more. See if the complete type of DERIVED contains
2371 such a virtual base. */
2374 }
2376 }
2379 /* The function for which we are trying to find a final overrider. */
2380 tree fn;
2381 /* The base class in which the function was declared. */
2382 tree declaring_base;
2383 /* The candidate overriders. */
2384 tree candidates;
2385 /* Path to most derived. */
2387 };
2389 /* Add the overrider along the current path to FFOD->CANDIDATES.
2390 Returns true if an overrider was found; false otherwise. */
2392 static bool
2396 {
2397 tree method;
2399 /* If BINFO is not the most derived type, try a more derived class.
2400 A definition there will overrider a definition here. */
2402 {
2403 depth--;
2407 }
2411 {
2414 /* Remove any candidates overridden by this new function. */
2416 {
2417 /* If *CANDIDATE overrides METHOD, then METHOD
2418 cannot override anything else on the list. */
2421 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2424 else
2426 }
2428 /* Add the new function. */
2431 }
2434 }
2436 /* Called from find_final_overrider via dfs_walk. */
2438 static tree
2440 {
2448 }
2450 static tree
2452 {
2457 }
2459 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2460 FN and whose TREE_VALUE is the binfo for the base where the
2461 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2462 DERIVED) is the base object in which FN is declared. */
2464 static tree
2466 {
2467 find_final_overrider_data ffod;
2469 /* Getting this right is a little tricky. This is valid:
2471 struct S { virtual void f (); };
2472 struct T { virtual void f (); };
2473 struct U : public S, public T { };
2475 even though calling `f' in `U' is ambiguous. But,
2477 struct R { virtual void f(); };
2478 struct S : virtual public R { virtual void f (); };
2479 struct T : virtual public R { virtual void f (); };
2480 struct U : public S, public T { };
2482 is not -- there's no way to decide whether to put `S::f' or
2483 `T::f' in the vtable for `R'.
2485 The solution is to look at all paths to BINFO. If we find
2486 different overriders along any two, then there is a problem. */
2490 /* Determine the depth of the hierarchy. */
2501 /* If there was no winner, issue an error message. */
2506 }
2508 /* Return the index of the vcall offset for FN when TYPE is used as a
2509 virtual base. */
2511 static tree
2513 {
2515 tree_pair_p p;
2523 /* There should always be an appropriate index. */
2525 }
2527 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2528 dominated by T. FN is the old function; VIRTUALS points to the
2529 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2530 of that entry in the list. */
2532 static void
2535 {
2536 tree b;
2537 tree overrider;
2538 tree delta;
2539 tree virtual_base;
2540 tree first_defn;
2546 /* Find the nearest primary base (possibly binfo itself) which defines
2547 this function; this is the class the caller will convert to when
2548 calling FN through BINFO. */
2550 {
2555 /* The nearest definition is from a lost primary. */
2558 }
2561 /* Find the final overrider. */
2564 {
2567 }
2570 /* Check for adjusting covariant return types. */
2578 /* If the overrider is invalid, don't even try. */
2580 {
2581 /* If FN is a covariant thunk, we must figure out the adjustment
2582 to the final base FN was converting to. As OVERRIDER_TARGET might
2583 also be converting to the return type of FN, we have to
2584 combine the two conversions here. */
2591 {
2595 }
2596 else
2600 /* Find the equivalent binfo within the return type of the
2601 overriding function. We will want the vbase offset from
2602 there. */
2604 over_return);
2607 {
2608 /* There was no existing virtual thunk (which takes
2609 precedence). So find the binfo of the base function's
2610 return type within the overriding function's return type.
2611 Fortunately we know the covariancy is valid (it
2612 has already been checked), so we can just iterate along
2613 the binfos, which have been chained in inheritance graph
2614 order. Of course it is lame that we have to repeat the
2615 search here anyway -- we should really be caching pieces
2616 of the vtable and avoiding this repeated work. */
2619 /* Find the base binfo within the overriding function's
2620 return type. We will always find a thunk_binfo, except
2621 when the covariancy is invalid (which we will have
2622 already diagnosed). */
2625 thunk_binfo;
2631 /* See if virtual inheritance is involved. */
2633 virtual_offset;
2640 {
2644 {
2645 /* We convert via virtual base. Adjust the fixed
2646 offset to be from there. */
2647 offset =
2651 }
2653 /* There was an existing fixed offset, this must be
2654 from the base just converted to, and the base the
2655 FN was thunking to. */
2657 else
2659 }
2660 }
2663 /* Replace the overriding function with a covariant thunk. We
2664 will emit the overriding function in its own slot as
2665 well. */
2668 }
2669 else
2673 /* If we need a covariant thunk, then we may need to adjust first_defn.
2674 The ABI specifies that the thunks emitted with a function are
2675 determined by which bases the function overrides, so we need to be
2676 sure that we're using a thunk for some overridden base; even if we
2677 know that the necessary this adjustment is zero, there may not be an
2678 appropriate zero-this-adjusment thunk for us to use since thunks for
2679 overriding virtual bases always use the vcall offset.
2681 Furthermore, just choosing any base that overrides this function isn't
2682 quite right, as this slot won't be used for calls through a type that
2683 puts a covariant thunk here. Calling the function through such a type
2684 will use a different slot, and that slot is the one that determines
2685 the thunk emitted for that base.
2687 So, keep looking until we find the base that we're really overriding
2688 in this slot: the nearest primary base that doesn't use a covariant
2689 thunk in this slot. */
2691 {
2693 /* We already know that the overrider needs a covariant thunk. */
2696 {
2703 }
2705 }
2707 /* Assume that we will produce a thunk that convert all the way to
2708 the final overrider, and not to an intermediate virtual base. */
2711 /* See if we can convert to an intermediate virtual base first, and then
2712 use the vcall offset located there to finish the conversion. */
2714 {
2715 /* If we find the final overrider, then we can stop
2716 walking. */
2721 /* If we find a virtual base, and we haven't yet found the
2722 overrider, then there is a virtual base between the
2723 declaring base (first_defn) and the final overrider. */
2725 {
2728 }
2729 }
2731 /* Compute the constant adjustment to the `this' pointer. The
2732 `this' pointer, when this function is called, will point at BINFO
2733 (or one of its primary bases, which are at the same offset). */
2735 /* The `this' pointer needs to be adjusted from the declaration to
2736 the nearest virtual base. */
2741 /* If the nearest definition is in a lost primary, we don't need an
2742 entry in our vtable. Except possibly in a constructor vtable,
2743 if we happen to get our primary back. In that case, the offset
2744 will be zero, as it will be a primary base. */
2746 else
2747 /* The `this' pointer needs to be adjusted from pointing to
2748 BINFO to pointing at the base where the final overrider
2749 appears. */
2760 else
2764 }
2766 /* Called from modify_all_vtables via dfs_walk. */
2768 static tree
2770 {
2772 tree virtuals;
2773 tree old_virtuals;
2777 /* A base without a vtable needs no modification, and its bases
2778 are uninteresting. */
2783 /* Don't do the primary vtable, if it's new. */
2787 /* There's no need to modify the vtable for a non-virtual primary
2788 base; we're not going to use that vtable anyhow. We do still
2789 need to do this for virtual primary bases, as they could become
2790 non-primary in a construction vtable. */
2795 /* Now, go through each of the virtual functions in the virtual
2796 function table for BINFO. Find the final overrider, and update
2797 the BINFO_VIRTUALS list appropriately. */
2800 virtuals;
2804 binfo,
2809 }
2811 /* Update all of the primary and secondary vtables for T. Create new
2812 vtables as required, and initialize their RTTI information. Each
2813 of the functions in VIRTUALS is declared in T and may override a
2814 virtual function from a base class; find and modify the appropriate
2815 entries to point to the overriding functions. Returns a list, in
2816 declaration order, of the virtual functions that are declared in T,
2817 but do not appear in the primary base class vtable, and which
2818 should therefore be appended to the end of the vtable for T. */
2820 static tree
2822 {
2826 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2830 /* Update all of the vtables. */
2833 /* Add virtual functions not already in our primary vtable. These
2834 will be both those introduced by this class, and those overridden
2835 from secondary bases. It does not include virtuals merely
2836 inherited from secondary bases. */
2838 {
2843 {
2844 /* We don't need to adjust the `this' pointer when
2845 calling this function. */
2849 /* This is a function not already in our vtable. Keep it. */
2851 }
2852 else
2853 /* We've already got an entry for this function. Skip it. */
2855 }
2858 }
2860 /* Get the base virtual function declarations in T that have the
2861 indicated NAME. */
2863 static void
2865 {
2866 tree methods;
2870 /* Find virtual functions in T with the indicated NAME. */
2875 methods;
2877 {
2882 {
2885 }
2886 }
2892 {
2895 }
2896 }
2898 /* If this declaration supersedes the declaration of
2899 a method declared virtual in the base class, then
2900 mark this field as being virtual as well. */
2902 void
2904 {
2907 /* In [temp.mem] we have:
2909 A specialization of a member function template does not
2910 override a virtual function from a base class. */
2917 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2918 the error_mark_node so that we know it is an overriding
2919 function. */
2920 {
2927 }
2930 {
2936 }
2941 }
2943 /* Warn about hidden virtual functions that are not overridden in t.
2944 We know that constructors and destructors don't apply. */
2946 static void
2948 {
2950 tree fns;
2953 /* We go through each separately named virtual function. */
2957 {
2958 tree fn;
2959 tree name;
2960 tree fndecl;
2961 tree base_binfo;
2962 tree binfo;
2965 /* All functions in this slot in the CLASSTYPE_METHOD_VEC will
2966 have the same name. Figure out what name that is. */
2968 /* There are no possibly hidden functions yet. */
2970 /* Iterate through all of the base classes looking for possibly
2971 hidden functions. */
2974 {
2977 }
2979 /* If there are no functions to hide, continue. */
2983 /* Remove any overridden functions. */
2985 {
2989 {
2990 /* If the method from the base class has the same
2991 signature as the method from the derived class, it
2992 has been overridden. */
2997 }
2998 }
3000 /* Now give a warning for all base functions without overriders,
3001 as they are hidden. */
3003 tree base_fndecl;
3006 {
3007 /* Here we know it is a hider, and no overrider exists. */
3009 OPT_Woverloaded_virtual,
3013 }
3014 }
3015 }
3017 /* Recursive helper for finish_struct_anon. */
3019 static void
3021 {
3025 {
3026 /* We're generally only interested in entities the user
3027 declared, but we also find nested classes by noticing
3028 the TYPE_DECL that we create implicitly. You're
3029 allowed to put one anonymous union inside another,
3030 though, so we explicitly tolerate that. We use
3031 TYPE_ANONYMOUS_P rather than ANON_AGGR_TYPE_P so that
3032 we also allow unnamed types used for defining fields. */
3039 {
3040 /* We already complained about static data members in
3041 finish_static_data_member_decl. */
3043 {
3046 "%q#D invalid; an anonymous union can "
3048 else
3050 "%q#D invalid; an anonymous struct can "
3052 }
3054 }
3057 {
3059 {
3063 else
3066 }
3068 {
3072 else
3075 }
3076 }
3081 /* Recurse into the anonymous aggregates to handle correctly
3082 access control (c++/24926):
3084 class A {
3085 union {
3086 union {
3087 int i;
3088 };
3089 };
3090 };
3092 int j=A().i; */
3096 }
3097 }
3099 /* Check for things that are invalid. There are probably plenty of other
3100 things we should check for also. */
3102 static void
3104 {
3106 {
3115 }
3116 }
3118 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
3119 will be used later during class template instantiation.
3120 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
3121 a non-static member data (FIELD_DECL), a member function
3122 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
3123 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
3124 When FRIEND_P is nonzero, T is either a friend class
3125 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
3126 (FUNCTION_DECL, TEMPLATE_DECL). */
3128 void
3130 {
3131 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
3136 }
3138 /* This function is called from declare_virt_assop_and_dtor via
3139 dfs_walk_all.
3141 DATA is a type that direcly or indirectly inherits the base
3142 represented by BINFO. If BINFO contains a virtual assignment [copy
3143 assignment or move assigment] operator or a virtual constructor,
3144 declare that function in DATA if it hasn't been already declared. */
3146 static tree
3148 {
3156 /* A base without a vtable needs no modification, and its bases
3157 are uninteresting. */
3161 /* If this is a primary base, then we have already looked at the
3162 virtual functions of its vtable. */
3166 {
3170 {
3175 }
3179 }
3182 }
3184 /* If the class type T has a direct or indirect base that contains a
3185 virtual assignment operator or a virtual destructor, declare that
3186 function in T if it hasn't been already declared. */
3188 static void
3190 {
3198 dfs_declare_virt_assop_and_dtor,
3200 }
3202 /* Declare the inheriting constructor for class T inherited from base
3203 constructor CTOR with the parameter array PARMS of size NPARMS. */
3205 static void
3207 {
3208 /* We don't declare an inheriting ctor that would be a default,
3209 copy or move ctor for derived or base. */
3214 {
3218 }
3227 {
3230 }
3231 }
3233 /* Declare all the inheriting constructors for class T inherited from base
3234 constructor CTOR. */
3236 static void
3238 {
3244 {
3248 }
3251 {
3255 }
3256 }
3258 /* Create default constructors, assignment operators, and so forth for
3259 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3260 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3261 the class cannot have a default constructor, copy constructor
3262 taking a const reference argument, or an assignment operator taking
3263 a const reference, respectively. */
3265 static void
3269 {
3277 /* Destructor. */
3279 {
3280 /* In general, we create destructors lazily. */
3285 /* But if this is a Java class, any non-trivial destructor is
3286 invalid, even if compiler-generated. Therefore, if the
3287 destructor is non-trivial we create it now. */
3289 }
3291 /* [class.ctor]
3293 If there is no user-declared constructor for a class, a default
3294 constructor is implicitly declared. */
3296 {
3301 /* This might force the declaration. */
3303 }
3305 /* [class.ctor]
3307 If a class definition does not explicitly declare a copy
3308 constructor, one is declared implicitly. */
3310 {
3316 }
3318 /* If there is no assignment operator, one will be created if and
3319 when it is needed. For now, just record whether or not the type
3320 of the parameter to the assignment operator will be a const or
3321 non-const reference. */
3323 {
3329 }
3331 /* We can't be lazy about declaring functions that might override
3332 a virtual function from a base class. */
3336 {
3340 {
3341 /* declare, then remove the decl */
3350 }
3351 else
3353 }
3354 }
3356 /* Subroutine of insert_into_classtype_sorted_fields. Recursively
3357 count the number of fields in TYPE, including anonymous union
3358 members. */
3360 static int
3362 {
3363 tree x;
3366 {
3369 else
3371 }
3373 }
3375 /* Subroutine of insert_into_classtype_sorted_fields. Recursively add
3376 all the fields in the TREE_LIST FIELDS to the SORTED_FIELDS_TYPE
3377 elts, starting at offset IDX. */
3379 static int
3381 {
3382 tree x;
3384 {
3387 else
3389 }
3391 }
3393 /* Add all of the enum values of ENUMTYPE, to the FIELD_VEC elts,
3394 starting at offset IDX. */
3396 static int
3400 {
3401 tree values;
3405 }
3407 /* FIELD is a bit-field. We are finishing the processing for its
3408 enclosing type. Issue any appropriate messages and set appropriate
3409 flags. Returns false if an error has been diagnosed. */
3411 static bool
3413 {
3415 tree w;
3417 /* Extract the declared width of the bitfield, which has been
3418 temporarily stashed in DECL_INITIAL. */
3421 /* Remove the bit-field width indicator so that the rest of the
3422 compiler does not treat that value as an initializer. */
3425 /* Detect invalid bit-field type. */
3427 {
3430 }
3431 else
3432 {
3434 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3437 /* detect invalid field size. */
3443 {
3446 }
3448 {
3451 }
3453 {
3456 }
3471 }
3474 {
3478 }
3479 else
3480 {
3481 /* Non-bit-fields are aligned for their type. */
3485 }
3486 }
3488 /* FIELD is a non bit-field. We are finishing the processing for its
3489 enclosing type T. Issue any appropriate messages and set appropriate
3490 flags. */
3492 static void
3494 tree t,
3498 {
3501 /* In C++98 an anonymous union cannot contain any fields which would change
3502 the settings of CANT_HAVE_CONST_CTOR and friends. */
3504 ;
3505 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3506 structs. So, we recurse through their fields here. */
3508 {
3509 tree fields;
3515 }
3516 /* Check members with class type for constructors, destructors,
3517 etc. */
3519 {
3520 /* Never let anything with uninheritable virtuals
3521 make it through without complaint. */
3525 {
3530 field);
3535 field);
3537 {
3541 }
3542 }
3543 else
3544 {
3557 }
3566 }
3571 {
3572 /* `build_class_init_list' does not recognize
3573 non-FIELD_DECLs. */
3577 }
3578 }
3580 /* Check the data members (both static and non-static), class-scoped
3581 typedefs, etc., appearing in the declaration of T. Issue
3582 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3583 declaration order) of access declarations; each TREE_VALUE in this
3584 list is a USING_DECL.
3586 In addition, set the following flags:
3588 EMPTY_P
3589 The class is empty, i.e., contains no non-static data members.
3591 CANT_HAVE_CONST_CTOR_P
3592 This class cannot have an implicitly generated copy constructor
3593 taking a const reference.
3595 CANT_HAVE_CONST_ASN_REF
3596 This class cannot have an implicitly generated assignment
3597 operator taking a const reference.
3599 All of these flags should be initialized before calling this
3600 function.
3602 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3603 fields can be added by adding to this chain. */
3605 static void
3609 {
3617 /* Assume there are no access declarations. */
3619 /* Assume this class has no pointer members. */
3621 /* Assume none of the members of this class have default
3622 initializations. */
3626 {
3634 {
3635 /* Save the access declarations for our caller. */
3638 }
3644 /* If we've gotten this far, it's a data member, possibly static,
3645 or an enumerator. */
3649 /* When this goes into scope, it will be a non-local reference. */
3654 {
3655 /* [class.union] (C++98)
3657 If a union contains a static data member, or a member of
3658 reference type, the program is ill-formed.
3660 In C++11 this limitation doesn't exist anymore. */
3662 {
3666 }
3668 {
3672 }
3673 }
3675 /* Perform error checking that did not get done in
3676 grokdeclarator. */
3678 {
3682 }
3684 {
3688 }
3696 /* Now it can only be a FIELD_DECL. */
3701 /* If at least one non-static data member is non-literal, the whole
3702 class becomes non-literal. Per Core/1453, volatile non-static
3703 data members and base classes are also not allowed.
3704 Note: if the type is incomplete we will complain later on. */
3709 /* A standard-layout class is a class that:
3710 ...
3711 has the same access control (Clause 11) for all non-static data members,
3712 ... */
3719 /* If this is of reference type, check if it needs an init. */
3721 {
3727 {
3728 /* ARM $12.6.2: [A member initializer list] (or, for an
3729 aggregate, initialization by a brace-enclosed list) is the
3730 only way to initialize nonstatic const and reference
3731 members. */
3734 }
3735 }
3740 {
3742 {
3743 warning_at
3746 x);
3748 }
3752 }
3755 /* We don't treat zero-width bitfields as making a class
3756 non-empty. */
3757 ;
3758 else
3759 {
3760 /* The class is non-empty. */
3762 /* The class is not even nearly empty. */
3764 /* If one of the data members contains an empty class,
3765 so does T. */
3769 }
3771 /* This is used by -Weffc++ (see below). Warn only for pointers
3772 to members which might hold dynamic memory. So do not warn
3773 for pointers to functions or pointers to members. */
3779 {
3784 }
3790 {
3792 {
3796 }
3798 {
3802 }
3803 }
3806 /* DR 148 now allows pointers to members (which are POD themselves),
3807 to be allowed in POD structs. */
3816 /* We set DECL_C_BIT_FIELD in grokbitfield.
3817 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3820 cant_have_const_ctor_p,
3821 no_const_asn_ref_p,
3824 /* Now that we've removed bit-field widths from DECL_INITIAL,
3825 anything left in DECL_INITIAL is an NSDMI that makes the class
3826 non-aggregate in C++11. */
3830 /* If any field is const, the structure type is pseudo-const. */
3832 {
3837 {
3838 /* ARM $12.6.2: [A member initializer list] (or, for an
3839 aggregate, initialization by a brace-enclosed list) is the
3840 only way to initialize nonstatic const and reference
3841 members. */
3844 }
3845 }
3846 /* A field that is pseudo-const makes the structure likewise. */
3848 {
3853 }
3855 /* Core issue 80: A nonstatic data member is required to have a
3856 different name from the class iff the class has a
3857 user-declared constructor. */
3862 }
3864 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3865 it should also define a copy constructor and an assignment operator to
3866 implement the correct copy semantic (deep vs shallow, etc.). As it is
3867 not feasible to check whether the constructors do allocate dynamic memory
3868 and store it within members, we approximate the warning like this:
3870 -- Warn only if there are members which are pointers
3871 -- Warn only if there is a non-trivial constructor (otherwise,
3872 there cannot be memory allocated).
3873 -- Warn only if there is a non-trivial destructor. We assume that the
3874 user at least implemented the cleanup correctly, and a destructor
3875 is needed to free dynamic memory.
3877 This seems enough for practical purposes. */
3879 && has_pointers
3883 {
3887 {
3892 }
3896 }
3898 /* Non-static data member initializers make the default constructor
3899 non-trivial. */
3901 {
3904 }
3906 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3910 /* Check anonymous struct/anonymous union fields. */
3913 /* We've built up the list of access declarations in reverse order.
3914 Fix that now. */
3916 }
3918 /* If TYPE is an empty class type, records its OFFSET in the table of
3919 OFFSETS. */
3921 static int
3923 {
3924 splay_tree_node n;
3929 /* Record the location of this empty object in OFFSETS. */
3937 type,
3941 }
3943 /* Returns nonzero if TYPE is an empty class type and there is
3944 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3946 static int
3948 {
3949 splay_tree_node n;
3950 tree t;
3955 /* Record the location of this empty object in OFFSETS. */
3965 }
3967 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3968 F for every subobject, passing it the type, offset, and table of
3969 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3970 be traversed.
3972 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3973 than MAX_OFFSET will not be walked.
3975 If F returns a nonzero value, the traversal ceases, and that value
3976 is returned. Otherwise, returns zero. */
3978 static int
3980 subobject_offset_fn f,
3981 tree offset,
3982 splay_tree offsets,
3983 tree max_offset,
3985 {
3989 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3990 stop. */
3998 {
4001 }
4004 {
4005 tree field;
4006 tree binfo;
4009 /* Avoid recursing into objects that are not interesting. */
4013 /* Record the location of TYPE. */
4018 /* Iterate through the direct base classes of TYPE. */
4022 {
4023 tree binfo_offset;
4028 tree orig_binfo;
4029 /* We cannot rely on BINFO_OFFSET being set for the base
4030 class yet, but the offsets for direct non-virtual
4031 bases can be calculated by going back to the TYPE. */
4034 offset,
4038 f,
4039 binfo_offset,
4040 offsets,
4041 max_offset,
4045 }
4048 {
4052 /* Iterate through the virtual base classes of TYPE. In G++
4053 3.2, we included virtual bases in the direct base class
4054 loop above, which results in incorrect results; the
4055 correct offsets for virtual bases are only known when
4056 working with the most derived type. */
4060 {
4062 f,
4064 offset,
4066 offsets,
4067 max_offset,
4071 }
4072 else
4073 {
4074 /* We still have to walk the primary base, if it is
4075 virtual. (If it is non-virtual, then it was walked
4076 above.) */
4082 {
4083 r = (walk_subobject_offsets
4088 }
4089 }
4090 }
4092 /* Iterate through the fields of TYPE. */
4097 {
4098 tree field_offset;
4103 f,
4105 offset,
4106 field_offset),
4107 offsets,
4108 max_offset,
4112 }
4113 }
4115 {
4118 tree index;
4120 /* Avoid recursing into objects that are not interesting. */
4126 /* Step through each of the elements in the array. */
4130 {
4132 f,
4133 offset,
4134 offsets,
4135 max_offset,
4141 /* If this new OFFSET is bigger than the MAX_OFFSET, then
4142 there's no point in iterating through the remaining
4143 elements of the array. */
4146 }
4147 }
4150 }
4152 /* Record all of the empty subobjects of TYPE (either a type or a
4153 binfo). If IS_DATA_MEMBER is true, then a non-static data member
4154 is being placed at OFFSET; otherwise, it is a base class that is
4155 being placed at OFFSET. */
4157 static void
4159 tree offset,
4160 splay_tree offsets,
4162 {
4163 tree max_offset;
4164 /* If recording subobjects for a non-static data member or a
4165 non-empty base class , we do not need to record offsets beyond
4166 the size of the biggest empty class. Additional data members
4167 will go at the end of the class. Additional base classes will go
4168 either at offset zero (if empty, in which case they cannot
4169 overlap with offsets past the size of the biggest empty class) or
4170 at the end of the class.
4172 However, if we are placing an empty base class, then we must record
4173 all offsets, as either the empty class is at offset zero (where
4174 other empty classes might later be placed) or at the end of the
4175 class (where other objects might then be placed, so other empty
4176 subobjects might later overlap). */
4180 else
4184 }
4186 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4187 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4188 virtual bases of TYPE are examined. */
4190 static int
4192 tree offset,
4193 splay_tree offsets,
4195 {
4196 splay_tree_node max_node;
4198 /* Get the node in OFFSETS that indicates the maximum offset where
4199 an empty subobject is located. */
4201 /* If there aren't any empty subobjects, then there's no point in
4202 performing this check. */
4208 vbases_p);
4209 }
4211 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4212 non-static data member of the type indicated by RLI. BINFO is the
4213 binfo corresponding to the base subobject, OFFSETS maps offsets to
4214 types already located at those offsets. This function determines
4215 the position of the DECL. */
4217 static void
4219 tree decl,
4220 tree binfo,
4221 splay_tree offsets)
4222 {
4225 tree type;
4228 {
4229 /* For the purposes of determining layout conflicts, we want to
4230 use the class type of BINFO; TREE_TYPE (DECL) will be the
4231 CLASSTYPE_AS_BASE version, which does not contain entries for
4232 zero-sized bases. */
4235 }
4236 else
4237 {
4240 }
4242 /* Try to place the field. It may take more than one try if we have
4243 a hard time placing the field without putting two objects of the
4244 same type at the same address. */
4246 {
4249 /* Place this field. */
4253 /* We have to check to see whether or not there is already
4254 something of the same type at the offset we're about to use.
4255 For example, consider:
4257 struct S {};
4258 struct T : public S { int i; };
4259 struct U : public S, public T {};
4261 Here, we put S at offset zero in U. Then, we can't put T at
4262 offset zero -- its S component would be at the same address
4263 as the S we already allocated. So, we have to skip ahead.
4264 Since all data members, including those whose type is an
4265 empty class, have nonzero size, any overlap can happen only
4266 with a direct or indirect base-class -- it can't happen with
4267 a data member. */
4268 /* In a union, overlap is permitted; all members are placed at
4269 offset zero. */
4274 {
4275 /* Strip off the size allocated to this field. That puts us
4276 at the first place we could have put the field with
4277 proper alignment. */
4280 /* Bump up by the alignment required for the type. */
4281 rli->bitpos
4287 }
4290 {
4291 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4292 the offset wasn't aligned like a pointer when we started to
4293 layout this field, that affects its position. */
4296 {
4299 "alignment of %qD increased in -fabi-version=9 "
4301 else
4304 }
4306 }
4307 else
4308 /* There was no conflict. We're done laying out this field. */
4310 }
4312 /* Now that we know where it will be placed, update its
4313 BINFO_OFFSET. */
4315 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4316 this point because their BINFO_OFFSET is copied from another
4317 hierarchy. Therefore, we may not need to add the entire
4318 OFFSET. */
4324 }
4326 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4328 static int
4330 tree offset,
4332 {
4334 }
4336 /* Layout the empty base BINFO. EOC indicates the byte currently just
4337 past the end of the class, and should be correctly aligned for a
4338 class of the type indicated by BINFO; OFFSETS gives the offsets of
4339 the empty bases allocated so far. T is the most derived
4340 type. Return nonzero iff we added it at the end. */
4342 static bool
4345 {
4346 tree alignment;
4350 /* This routine should only be used for empty classes. */
4355 propagate_binfo_offsets
4359 /* This is an empty base class. We first try to put it at offset
4360 zero. */
4363 offsets,
4365 {
4366 /* That didn't work. Now, we move forward from the next
4367 available spot in the class. */
4371 {
4374 offsets,
4376 /* We finally found a spot where there's no overlap. */
4379 /* There's overlap here, too. Bump along to the next spot. */
4381 }
4382 }
4385 {
4390 }
4393 }
4395 /* Layout the base given by BINFO in the class indicated by RLI.
4396 *BASE_ALIGN is a running maximum of the alignments of
4397 any base class. OFFSETS gives the location of empty base
4398 subobjects. T is the most derived type. Return nonzero if the new
4399 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4400 *NEXT_FIELD, unless BINFO is for an empty base class.
4402 Returns the location at which the next field should be inserted. */
4407 {
4412 /* This error is now reported in xref_tag, thus giving better
4413 location information. */
4416 /* Place the base class. */
4418 {
4419 tree decl;
4421 /* The containing class is non-empty because it has a non-empty
4422 base class. */
4425 /* Create the FIELD_DECL. */
4432 {
4440 /* Try to place the field. It may take more than one try if we
4441 have a hard time placing the field without putting two
4442 objects of the same type at the same address. */
4444 /* Add the new FIELD_DECL to the list of fields for T. */
4448 }
4449 }
4450 else
4451 {
4452 tree eoc;
4455 /* On some platforms (ARM), even empty classes will not be
4456 byte-aligned. */
4461 /* A nearly-empty class "has no proper base class that is empty,
4462 not morally virtual, and at an offset other than zero." */
4464 {
4467 /* The check above (used in G++ 3.2) is insufficient because
4468 an empty class placed at offset zero might itself have an
4469 empty base at a nonzero offset. */
4471 empty_base_at_nonzero_offset_p,
4472 size_zero_node,
4477 }
4479 /* We do not create a FIELD_DECL for empty base classes because
4480 it might overlap some other field. We want to be able to
4481 create CONSTRUCTORs for the class by iterating over the
4482 FIELD_DECLs, and the back end does not handle overlapping
4483 FIELD_DECLs. */
4485 /* An empty virtual base causes a class to be non-empty
4486 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4487 here because that was already done when the virtual table
4488 pointer was created. */
4489 }
4491 /* Record the offsets of BINFO and its base subobjects. */
4494 offsets,
4498 }
4500 /* Layout all of the non-virtual base classes. Record empty
4501 subobjects in OFFSETS. T is the most derived type. Return nonzero
4502 if the type cannot be nearly empty. The fields created
4503 corresponding to the base classes will be inserted at
4504 *NEXT_FIELD. */
4506 static void
4509 {
4510 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4511 subobjects. */
4516 /* The primary base class is always allocated first. */
4521 /* Now allocate the rest of the bases. */
4523 {
4524 tree base_binfo;
4528 /* The primary base was already allocated above, so we don't
4529 need to allocate it again here. */
4533 /* Virtual bases are added at the end (a primary virtual base
4534 will have already been added). */
4540 }
4541 }
4543 /* Go through the TYPE_METHODS of T issuing any appropriate
4544 diagnostics, figuring out which methods override which other
4545 methods, and so forth. */
4547 static void
4549 {
4550 tree x;
4553 {
4557 /* The name of the field is the original field name
4558 Save this in auxiliary field for later overloading. */
4560 {
4564 }
4565 /* All user-provided destructors are non-trivial.
4566 Constructors and assignment ops are handled in
4567 grok_special_member_properties. */
4573 "%<transaction_safe_dynamic%> may only be specified for "
4575 }
4576 }
4578 /* FN is a constructor or destructor. Clone the declaration to create
4579 a specialized in-charge or not-in-charge version, as indicated by
4580 NAME. */
4582 static tree
4584 {
4585 tree parms;
4586 tree clone;
4588 /* Copy the function. */
4590 /* Reset the function name. */
4592 /* Remember where this function came from. */
4594 /* Make it easy to find the CLONE given the FN. */
4598 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4600 {
4607 }
4608 else
4609 {
4610 // Clone constraints.
4614 }
4619 /* There's no pending inline data for this function. */
4623 /* The base-class destructor is not virtual. */
4625 {
4629 }
4631 /* If there was an in-charge parameter, drop it from the function
4632 type. */
4634 {
4635 tree basetype;
4636 tree parmtypes;
4637 tree exceptions;
4642 /* Skip the `this' parameter. */
4644 /* Skip the in-charge parameter. */
4646 /* And the VTT parm, in a complete [cd]tor. */
4650 /* If this is subobject constructor or destructor, add the vtt
4651 parameter. */
4655 parmtypes);
4658 exceptions);
4662 }
4664 /* Copy the function parameters. */
4666 /* Remove the in-charge parameter. */
4668 {
4672 }
4673 /* And the VTT parm, in a complete [cd]tor. */
4675 {
4678 else
4679 {
4683 }
4684 }
4687 {
4690 }
4692 /* Create the RTL for this function. */
4697 }
4699 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4700 not invoke this function directly.
4702 For a non-thunk function, returns the address of the slot for storing
4703 the function it is a clone of. Otherwise returns NULL_TREE.
4705 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4706 cloned_function is unset. This is to support the separate
4707 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4708 on a template makes sense, but not the former. */
4710 tree *
4712 {
4720 {
4721 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4724 else
4725 #endif
4727 }
4732 else
4734 }
4736 /* Produce declarations for all appropriate clones of FN. If
4737 UPDATE_METHOD_VEC_P is nonzero, the clones are added to the
4738 CLASTYPE_METHOD_VEC as well. */
4740 void
4742 {
4743 tree clone;
4745 /* Avoid inappropriate cloning. */
4751 {
4752 /* For each constructor, we need two variants: an in-charge version
4753 and a not-in-charge version. */
4760 }
4761 else
4762 {
4765 /* For each destructor, we need three variants: an in-charge
4766 version, a not-in-charge version, and an in-charge deleting
4767 version. We clone the deleting version first because that
4768 means it will go second on the TYPE_METHODS list -- and that
4769 corresponds to the correct layout order in the virtual
4770 function table.
4772 For a non-virtual destructor, we do not build a deleting
4773 destructor. */
4775 {
4779 }
4786 }
4788 /* Note that this is an abstract function that is never emitted. */
4790 }
4792 /* DECL is an in charge constructor, which is being defined. This will
4793 have had an in class declaration, from whence clones were
4794 declared. An out-of-class definition can specify additional default
4795 arguments. As it is the clones that are involved in overload
4796 resolution, we must propagate the information from the DECL to its
4797 clones. */
4799 void
4801 {
4802 tree clone;
4806 {
4813 /* Skip the 'this' parameter. */
4829 {
4834 {
4835 /* A default parameter has been added. Adjust the
4836 clone's parameters. */
4840 tree type;
4845 {
4848 clone_parms);
4850 }
4853 clone_parms);
4862 }
4863 }
4865 }
4866 }
4868 /* For each of the constructors and destructors in T, create an
4869 in-charge and not-in-charge variant. */
4871 static void
4873 {
4874 tree fns;
4876 /* If for some reason we don't have a CLASSTYPE_METHOD_VEC, we bail
4877 out now. */
4885 }
4887 /* Deduce noexcept for a destructor DTOR. */
4889 void
4891 {
4893 {
4896 }
4897 }
4899 /* For each destructor in T, deduce noexcept:
4901 12.4/3: A declaration of a destructor that does not have an
4902 exception-specification is implicitly considered to have the
4903 same exception-specification as an implicit declaration (15.4). */
4905 static void
4907 {
4908 /* If for some reason we don't have a CLASSTYPE_METHOD_VEC, we bail
4909 out now. */
4915 }
4917 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4918 of TYPE for virtual functions which FNDECL overrides. Return a
4919 mask of the tm attributes found therein. */
4921 static int
4923 {
4925 tree base_binfo;
4929 {
4937 {
4941 else
4944 }
4945 else
4947 }
4950 }
4952 /* Subroutine of set_method_tm_attributes. Handle the checks and
4953 inheritance for one virtual method FNDECL. */
4955 static void
4957 {
4958 tree tm_attr;
4963 /* If FNDECL doesn't actually override anything (i.e. T is the
4964 class that first declares FNDECL virtual), then we're done. */
4971 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4972 tm_pure must match exactly, otherwise no weakening of
4973 tm_safe > tm_callable > nothing. */
4974 /* ??? The tm_pure attribute didn't make the transition to the
4975 multivendor language spec. */
4977 {
4979 {
4982 }
4983 }
4984 /* If the overridden function is tm_pure, then FNDECL must be. */
4987 /* Look for base class combinations that cannot be satisfied. */
4989 {
4995 }
4996 /* If FNDECL did not declare an attribute, then inherit the most
4997 restrictive one. */
4999 {
5001 }
5002 /* Otherwise validate that we're not weaker than a function
5003 that is being overridden. */
5004 else
5005 {
5009 }
5012 err_override:
5016 }
5018 /* For each of the methods in T, propagate a class-level tm attribute. */
5020 static void
5022 {
5025 /* Don't bother collecting tm attributes if transactional memory
5026 support is not enabled. */
5030 /* Process virtual methods first, as they inherit directly from the
5031 base virtual function and also require validation of new attributes. */
5033 {
5034 tree vchain;
5037 {
5042 }
5043 }
5045 /* If the class doesn't have an attribute, nothing more to do. */
5050 /* Any method that does not yet have a tm attribute inherits
5051 the one from the class. */
5053 {
5056 }
5057 }
5059 /* Returns true iff class T has a user-defined constructor other than
5060 the default constructor. */
5062 bool
5064 {
5065 tree fns;
5071 {
5078 }
5081 }
5083 /* Returns the defaulted constructor if T has one. Otherwise, returns
5084 NULL_TREE. */
5086 tree
5088 {
5095 {
5099 {
5105 }
5106 }
5109 }
5111 /* Returns true iff FN is a user-provided function, i.e. user-declared
5112 and not defaulted at its first declaration; or explicit, private,
5113 protected, or non-const. */
5115 bool
5117 {
5120 else
5124 }
5126 /* Returns true iff class T has a user-provided constructor. */
5128 bool
5130 {
5131 tree fns;
5139 /* This can happen in error cases; avoid crashing. */
5148 }
5150 /* Returns true iff class T has a user-provided or explicit constructor. */
5152 bool
5154 {
5155 tree fns;
5163 /* This can happen in error cases; avoid crashing. */
5168 {
5172 }
5175 }
5177 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5178 declared or explicitly defaulted in the class body) default
5179 constructor. */
5181 bool
5183 {
5184 tree fns;
5192 {
5198 }
5201 }
5203 /* TYPE is being used as a virtual base, and has a non-trivial move
5204 assignment. Return true if this is due to there being a user-provided
5205 move assignment in TYPE or one of its subobjects; if there isn't, then
5206 multiple move assignment can't cause any harm. */
5208 bool
5210 {
5211 /* Does the type itself have a user-provided move assignment operator? */
5215 {
5219 }
5221 /* Do any of its bases? */
5223 tree base_binfo;
5228 /* Or non-static data members? */
5230 {
5235 }
5237 /* Seems not. */
5239 }
5241 /* If default-initialization leaves part of TYPE uninitialized, returns
5242 a DECL for the field or TYPE itself (DR 253). */
5244 tree
5246 {
5257 {
5261 }
5266 {
5270 }
5273 }
5275 /* Returns true iff for class T, a trivial synthesized default constructor
5276 would be constexpr. */
5278 bool
5280 {
5281 /* A defaulted trivial default constructor is constexpr
5282 if there is nothing to initialize. */
5285 }
5287 /* Returns true iff class T has a constexpr default constructor. */
5289 bool
5291 {
5292 tree fns;
5295 {
5296 /* The caller should have stripped an enclosing array. */
5299 }
5301 {
5304 /* Non-trivial, we need to check subobject constructors. */
5306 }
5309 }
5311 /* Returns true iff class TYPE has a virtual destructor. */
5313 bool
5315 {
5316 tree dtor;
5324 }
5326 /* Returns true iff class T has a move constructor. */
5328 bool
5330 {
5331 tree fns;
5334 {
5337 }
5347 }
5349 /* Returns true iff class T has a move assignment operator. */
5351 bool
5353 {
5354 tree fns;
5357 {
5360 }
5368 }
5370 /* Returns true iff class T has a move constructor that was explicitly
5371 declared in the class body. Note that this is different from
5372 "user-provided", which doesn't include functions that are defaulted in
5373 the class. */
5375 bool
5377 {
5378 tree fns;
5387 {
5391 }
5394 }
5396 /* Returns true iff class T has a move assignment operator that was
5397 explicitly declared in the class body. */
5399 bool
5401 {
5402 tree fns;
5409 {
5413 }
5416 }
5418 /* Nonzero if we need to build up a constructor call when initializing an
5419 object of this class, either because it has a user-declared constructor
5420 or because it doesn't have a default constructor (so we need to give an
5421 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5422 what you care about is whether or not an object can be produced by a
5423 constructor (e.g. so we don't set TREE_READONLY on const variables of
5424 such type); use this function when what you care about is whether or not
5425 to try to call a constructor to create an object. The latter case is
5426 the former plus some cases of constructors that cannot be called. */
5428 bool
5430 {
5431 tree inner;
5441 /* A user-declared constructor might be private, and a constructor might
5442 be trivial but deleted. */
5445 {
5450 }
5452 }
5454 /* Like type_build_ctor_call, but for destructors. */
5456 bool
5458 {
5459 tree inner;
5468 /* A user-declared destructor might be private, and a destructor might
5469 be trivial but deleted. */
5472 {
5477 }
5479 }
5481 /* Remove all zero-width bit-fields from T. */
5483 static void
5485 {
5490 {
5493 /* We should not be confused by the fact that grokbitfield
5494 temporarily sets the width of the bit field into
5495 DECL_INITIAL (*fieldsp).
5496 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5497 to that width. */
5501 else
5503 }
5504 }
5506 /* Returns TRUE iff we need a cookie when dynamically allocating an
5507 array whose elements have the indicated class TYPE. */
5509 static bool
5511 {
5512 tree fns;
5517 /* If there's a non-trivial destructor, we need a cookie. In order
5518 to iterate through the array calling the destructor for each
5519 element, we'll have to know how many elements there are. */
5523 /* If the usual deallocation function is a two-argument whose second
5524 argument is of type `size_t', then we have to pass the size of
5525 the array to the deallocation function, so we will need to store
5526 a cookie. */
5530 /* If there are no `operator []' members, or the lookup is
5531 ambiguous, then we don't need a cookie. */
5534 /* Loop through all of the functions. */
5536 {
5537 tree fn;
5538 tree second_parm;
5540 /* Select the current function. */
5542 /* See if this function is a one-argument delete function. If
5543 it is, then it will be the usual deallocation function. */
5547 /* Do not consider this function if its second argument is an
5548 ellipsis. */
5551 /* Otherwise, if we have a two-argument function and the second
5552 argument is `size_t', it will be the usual deallocation
5553 function -- unless there is one-argument function, too. */
5557 }
5560 }
5562 /* Finish computing the `literal type' property of class type T.
5564 At this point, we have already processed base classes and
5565 non-static data members. We need to check whether the copy
5566 constructor is trivial, the destructor is trivial, and there
5567 is a trivial default constructor or at least one constexpr
5568 constructor other than the copy constructor. */
5570 static void
5572 {
5573 tree fn;
5589 {
5592 {
5596 }
5597 }
5598 }
5600 /* T is a non-literal type used in a context which requires a constant
5601 expression. Explain why it isn't literal. */
5603 void
5605 {
5615 /* Already explained. */
5624 {
5626 "default constructor, and has no constexpr constructor that "
5629 {
5630 /* Note that we can't simply call locate_ctor because when the
5631 constructor is deleted it just returns NULL_TREE. */
5632 tree fns;
5634 {
5641 {
5644 else
5647 }
5648 }
5649 }
5650 }
5651 else
5652 {
5656 {
5659 {
5664 }
5665 }
5667 {
5668 tree ftype;
5673 {
5676 field);
5679 }
5683 }
5684 }
5685 }
5687 /* Check the validity of the bases and members declared in T. Add any
5688 implicitly-generated functions (like copy-constructors and
5689 assignment operators). Compute various flag bits (like
5690 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5691 level: i.e., independently of the ABI in use. */
5693 static void
5695 {
5696 /* Nonzero if the implicitly generated copy constructor should take
5697 a non-const reference argument. */
5699 /* Nonzero if the implicitly generated assignment operator
5700 should take a non-const reference argument. */
5702 tree access_decls;
5705 tree fn;
5707 /* By default, we use const reference arguments and generate default
5708 constructors. */
5712 /* Check all the base-classes and set FMEM members to point to arrays
5713 of potential interest. */
5716 /* Deduce noexcept on destructors. This needs to happen after we've set
5717 triviality flags appropriately for our bases. */
5721 /* Check all the method declarations. */
5724 /* Save the initial values of these flags which only indicate whether
5725 or not the class has user-provided functions. As we analyze the
5726 bases and members we can set these flags for other reasons. */
5730 /* Check all the data member declarations. We cannot call
5731 check_field_decls until we have called check_bases check_methods,
5732 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5733 being set appropriately. */
5738 /* A nearly-empty class has to be vptr-containing; a nearly empty
5739 class contains just a vptr. */
5743 /* Do some bookkeeping that will guide the generation of implicitly
5744 declared member functions. */
5747 /* We need to call a constructor for this class if it has a
5748 user-provided constructor, or if the default constructor is going
5749 to initialize the vptr. (This is not an if-and-only-if;
5750 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5751 themselves need constructing.) */
5754 /* [dcl.init.aggr]
5756 An aggregate is an array or a class with no user-provided
5757 constructors ... and no virtual functions.
5759 Again, other conditions for being an aggregate are checked
5760 elsewhere. */
5764 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5765 retain the old definition internally for ABI reasons. */
5774 /* If the only explicitly declared default constructor is user-provided,
5775 set TYPE_HAS_COMPLEX_DFLT. */
5781 /* Warn if a public base of a polymorphic type has an accessible
5782 non-virtual destructor. It is only now that we know the class is
5783 polymorphic. Although a polymorphic base will have a already
5784 been diagnosed during its definition, we warn on use too. */
5786 {
5789 tree base_binfo;
5793 {
5801 basetype);
5802 }
5803 }
5805 /* If the class has no user-declared constructor, but does have
5806 non-static const or reference data members that can never be
5807 initialized, issue a warning. */
5809 /* Classes with user-declared constructors are presumed to
5810 initialize these members. */
5812 /* Aggregates can be initialized with brace-enclosed
5813 initializers. */
5815 {
5816 tree field;
5819 {
5820 tree type;
5837 }
5838 }
5840 /* Synthesize any needed methods. */
5842 cant_have_const_ctor,
5843 no_const_asn_ref);
5845 /* Check defaulted declarations here so we have cant_have_const_ctor
5846 and don't need to worry about clones. */
5849 {
5852 {
5853 bool imp_const_p
5859 /* If the function is defaulted outside the class, we just
5860 give the synthesis error. */
5863 }
5865 }
5868 {
5869 /* "This class type is not an aggregate." */
5871 }
5873 /* Compute the 'literal type' property before we
5874 do anything with non-static member functions. */
5877 /* Create the in-charge and not-in-charge variants of constructors
5878 and destructors. */
5881 /* Process the using-declarations. */
5885 /* Build and sort the CLASSTYPE_METHOD_VEC. */
5888 /* Figure out whether or not we will need a cookie when dynamically
5889 allocating an array of this type. */
5892 }
5894 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5895 accordingly. If a new vfield was created (because T doesn't have a
5896 primary base class), then the newly created field is returned. It
5897 is not added to the TYPE_FIELDS list; it is the caller's
5898 responsibility to do that. Accumulate declared virtual functions
5899 on VIRTUALS_P. */
5901 static tree
5903 {
5904 tree fn;
5906 /* Collect the virtual functions declared in T. */
5911 {
5920 }
5922 /* If we couldn't find an appropriate base class, create a new field
5923 here. Even if there weren't any new virtual functions, we might need a
5924 new virtual function table if we're supposed to include vptrs in
5925 all classes that need them. */
5927 {
5928 /* We build this decl with vtbl_ptr_type_node, which is a
5929 `vtable_entry_type*'. It might seem more precise to use
5930 `vtable_entry_type (*)[N]' where N is the number of virtual
5931 functions. However, that would require the vtable pointer in
5932 base classes to have a different type than the vtable pointer
5933 in derived classes. We could make that happen, but that
5934 still wouldn't solve all the problems. In particular, the
5935 type-based alias analysis code would decide that assignments
5936 to the base class vtable pointer can't alias assignments to
5937 the derived class vtable pointer, since they have different
5938 types. Thus, in a derived class destructor, where the base
5939 class constructor was inlined, we could generate bad code for
5940 setting up the vtable pointer.
5942 Therefore, we use one type for all vtable pointers. We still
5943 use a type-correct type; it's just doesn't indicate the array
5944 bounds. That's better than using `void*' or some such; it's
5945 cleaner, and it let's the alias analysis code know that these
5946 stores cannot alias stores to void*! */
5947 tree field;
5960 /* This class is non-empty. */
5964 }
5967 }
5969 /* Add OFFSET to all base types of BINFO which is a base in the
5970 hierarchy dominated by T.
5972 OFFSET, which is a type offset, is number of bytes. */
5974 static void
5976 {
5978 tree primary_binfo;
5979 tree base_binfo;
5981 /* Update BINFO's offset. */
5986 offset));
5988 /* Find the primary base class. */
5994 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5995 downwards. */
5997 {
5998 /* Don't do the primary base twice. */
6006 }
6007 }
6009 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
6010 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
6011 empty subobjects of T. */
6013 static void
6015 {
6016 tree vbase;
6023 /* Find the last field. The artificial fields created for virtual
6024 bases will go after the last extant field to date. */
6029 /* Go through the virtual bases, allocating space for each virtual
6030 base that is not already a primary base class. These are
6031 allocated in inheritance graph order. */
6033 {
6038 {
6039 /* This virtual base is not a primary base of any class in the
6040 hierarchy, so we have to add space for it. */
6043 }
6044 }
6045 }
6047 /* Returns the offset of the byte just past the end of the base class
6048 BINFO. */
6050 static tree
6052 {
6053 tree size;
6058 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
6059 allocate some space for it. It cannot have virtual bases, so
6060 TYPE_SIZE_UNIT is fine. */
6062 else
6066 }
6068 /* Returns the offset of the byte just past the end of the base class
6069 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
6070 only non-virtual bases are included. */
6072 static tree
6074 {
6077 tree binfo;
6078 tree base_binfo;
6079 tree offset;
6084 {
6094 }
6099 {
6103 }
6106 }
6108 /* Warn about bases of T that are inaccessible because they are
6109 ambiguous. For example:
6111 struct S {};
6112 struct T : public S {};
6113 struct U : public S, public T {};
6115 Here, `(S*) new U' is not allowed because there are two `S'
6116 subobjects of U. */
6118 static void
6120 {
6123 tree basetype;
6124 tree binfo;
6125 tree base_binfo;
6127 /* If there are no repeated bases, nothing can be ambiguous. */
6131 /* Check direct bases. */
6134 {
6140 }
6142 /* Check for ambiguous virtual bases. */
6146 {
6152 }
6153 }
6155 /* Compare two INTEGER_CSTs K1 and K2. */
6157 static int
6159 {
6161 }
6163 /* Increase the size indicated in RLI to account for empty classes
6164 that are "off the end" of the class. */
6166 static void
6168 {
6169 tree eoc;
6170 tree rli_size;
6172 /* It might be the case that we grew the class to allocate a
6173 zero-sized base class. That won't be reflected in RLI, yet,
6174 because we are willing to overlay multiple bases at the same
6175 offset. However, now we need to make sure that RLI is big enough
6176 to reflect the entire class. */
6182 {
6183 /* The size should have been rounded to a whole byte. */
6186 rli->bitpos
6195 }
6196 }
6198 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
6199 BINFO_OFFSETs for all of the base-classes. Position the vtable
6200 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
6202 static void
6204 {
6205 tree non_static_data_members;
6206 tree field;
6207 tree vptr;
6208 record_layout_info rli;
6209 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6210 types that appear at that offset. */
6211 splay_tree empty_base_offsets;
6212 /* True if the last field laid out was a bit-field. */
6214 /* The location at which the next field should be inserted. */
6216 /* T, as a base class. */
6217 tree base_t;
6219 /* Keep track of the first non-static data member. */
6222 /* Start laying out the record. */
6225 /* Mark all the primary bases in the hierarchy. */
6228 /* Create a pointer to our virtual function table. */
6231 /* The vptr is always the first thing in the class. */
6233 {
6238 }
6239 else
6242 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6247 /* Layout the non-static data members. */
6249 {
6250 tree type;
6251 tree padding;
6253 /* We still pass things that aren't non-static data members to
6254 the back end, in case it wants to do something with them. */
6256 {
6258 /* If the static data member has incomplete type, keep track
6259 of it so that it can be completed later. (The handling
6260 of pending statics in finish_record_layout is
6261 insufficient; consider:
6263 struct S1;
6264 struct S2 { static S1 s1; };
6266 At this point, finish_record_layout will be called, but
6267 S1 is still incomplete.) */
6269 {
6271 /* The visibility of static data members is determined
6272 at their point of declaration, not their point of
6273 definition. */
6275 }
6277 }
6285 /* If this field is a bit-field whose width is greater than its
6286 type, then there are some special rules for allocating
6287 it. */
6290 {
6292 tree integer_type;
6294 /* We must allocate the bits as if suitably aligned for the
6295 longest integer type that fits in this many bits. type
6296 of the field. Then, we are supposed to use the left over
6297 bits as additional padding. */
6306 /* ITK now indicates a type that is too large for the
6307 field. We have to back up by one to find the largest
6308 type that fits. */
6309 do
6310 {
6315 /* Figure out how much additional padding is required. */
6317 {
6319 /* In a union, the padding field must have the full width
6320 of the bit-field; all fields start at offset zero. */
6322 else
6325 }
6327 /* An unnamed bitfield does not normally affect the
6328 alignment of the containing class on a target where
6329 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6330 make any exceptions for unnamed bitfields when the
6331 bitfields are longer than their types. Therefore, we
6332 temporarily give the field a name. */
6334 {
6337 }
6343 empty_base_offsets);
6346 /* Now that layout has been performed, set the size of the
6347 field to the size of its declared type; the rest of the
6348 field is effectively invisible. */
6350 /* We must also reset the DECL_MODE of the field. */
6352 }
6353 else
6355 empty_base_offsets);
6357 /* Remember the location of any empty classes in FIELD. */
6360 empty_base_offsets,
6363 /* If a bit-field does not immediately follow another bit-field,
6364 and yet it starts in the middle of a byte, we have failed to
6365 comply with the ABI. */
6368 /* The TREE_NO_WARNING flag gets set by Objective-C when
6369 laying out an Objective-C class. The ObjC ABI differs
6370 from the C++ ABI, and so we do not want a warning
6371 here. */
6373 && !last_field_was_bitfield
6376 bitsize_unit_node)))
6378 "offset of %qD is not ABI-compliant and may "
6381 /* The middle end uses the type of expressions to determine the
6382 possible range of expression values. In order to optimize
6383 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6384 must be made aware of the width of "i", via its type.
6386 Because C++ does not have integer types of arbitrary width,
6387 we must (for the purposes of the front end) convert from the
6388 type assigned here to the declared type of the bitfield
6389 whenever a bitfield expression is used as an rvalue.
6390 Similarly, when assigning a value to a bitfield, the value
6391 must be converted to the type given the bitfield here. */
6393 {
6398 {
6405 }
6406 }
6408 /* If we needed additional padding after this field, add it
6409 now. */
6411 {
6412 tree padding_field;
6415 FIELD_DECL,
6416 NULL_TREE,
6417 char_type_node);
6424 NULL_TREE,
6425 empty_base_offsets);
6426 }
6429 }
6432 {
6433 /* Make sure that we are on a byte boundary so that the size of
6434 the class without virtual bases will always be a round number
6435 of bytes. */
6438 }
6440 /* Delete all zero-width bit-fields from the list of fields. Now
6441 that the type is laid out they are no longer important. */
6444 /* Create the version of T used for virtual bases. We do not use
6445 make_class_type for this version; this is an artificial type. For
6446 a POD type, we just reuse T. */
6448 {
6451 /* Set the size and alignment for the new type. */
6452 tree eoc;
6454 /* If the ABI version is not at least two, and the last
6455 field was a bit-field, RLI may not be on a byte
6456 boundary. In particular, rli_size_unit_so_far might
6457 indicate the last complete byte, while rli_size_so_far
6458 indicates the total number of bits used. Therefore,
6459 rli_size_so_far, rather than rli_size_unit_so_far, is
6460 used to compute TYPE_SIZE_UNIT. */
6468 eoc);
6478 /* Copy the fields from T. */
6482 {
6486 }
6489 /* Record the base version of the type. */
6492 }
6493 else
6496 /* Every empty class contains an empty class. */
6500 /* Set the TYPE_DECL for this type to contain the right
6501 value for DECL_OFFSET, so that we can use it as part
6502 of a COMPONENT_REF for multiple inheritance. */
6505 /* Now fix up any virtual base class types that we left lying
6506 around. We must get these done before we try to lay out the
6507 virtual function table. As a side-effect, this will remove the
6508 base subobject fields. */
6511 /* Make sure that empty classes are reflected in RLI at this
6512 point. */
6515 /* Make sure not to create any structures with zero size. */
6521 /* If this is a non-POD, declaring it packed makes a difference to how it
6522 can be used as a field; don't let finalize_record_size undo it. */
6526 /* Let the back end lay out the type. */
6535 /* Warn about bases that can't be talked about due to ambiguity. */
6538 /* Now that we're done with layout, give the base fields the real types. */
6543 /* Clean up. */
6550 }
6552 /* Determine the "key method" for the class type indicated by TYPE,
6553 and set CLASSTYPE_KEY_METHOD accordingly. */
6555 void
6557 {
6558 tree method;
6561 || processing_template_decl
6566 /* The key method is the first non-pure virtual function that is not
6567 inline at the point of class definition. On some targets the
6568 key function may not be inline; those targets should not call
6569 this function until the end of the translation unit. */
6576 {
6579 }
6582 }
6585 /* Allocate and return an instance of struct sorted_fields_type with
6586 N fields. */
6590 {
6597 }
6599 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6600 class data member of non-zero size, otherwise false. */
6604 {
6612 {
6616 }
6619 }
6621 /* Used by find_flexarrays and related. */
6623 /* The first flexible array member or non-zero array member found
6624 in order of layout. */
6625 tree array;
6626 /* First non-static non-empty data member in the class or its bases. */
6627 tree first;
6628 /* First non-static non-empty data member following either the flexible
6629 array member, if found, or the zero-length array member. */
6630 tree after;
6631 };
6633 /* Find either the first flexible array member or the first zero-length
6634 array, in that order or preference, among members of class T (but not
6635 its base classes), and set members of FMEM accordingly. */
6637 static void
6639 {
6641 {
6642 /* Find the next non-static data member if it exists. */
6651 {
6652 /* Members of anonymous structs and unions are treated as if
6653 they were members of the containing class. Descend into
6654 the anonymous struct or union and find a flexible array
6655 member or zero-length array among its fields. */
6658 }
6660 /* Skip anything that's not a (non-static) data member. */
6664 /* Skip virtual table pointers. */
6669 {
6670 /* Remember the first non-static data member. */
6674 /* Remember the first non-static data member after the flexible
6675 array member, if one has been found, or the zero-length array
6676 if it has been found. */
6679 }
6681 /* Skip non-arrays. */
6685 /* Determine the upper bound of the array if it has one. */
6687 {
6689 {
6690 /* Make a record of the zero-length array if either one
6691 such field or a flexible array member has been seen to
6692 handle the pathological and unlikely case of multiple
6693 such members. */
6696 }
6698 /* Remember the first zero-length array unless a flexible array
6699 member has already been seen. */
6701 }
6702 else
6703 {
6704 /* Flexible array members have no upper bound. */
6706 {
6707 /* Replace the zero-length array if it's been stored and
6708 reset the after pointer. */
6710 {
6713 }
6714 }
6715 else
6717 }
6718 }
6719 }
6721 /* Issue diagnostics for invalid flexible array members or zero-length
6722 arrays that are not the last elements of the containing class or its
6723 base classes or that are its sole members. */
6725 static void
6727 {
6728 /* Members of anonymous structs and unions are considered to be members
6729 of the containing struct or union. */
6736 {
6746 }
6747 else
6748 {
6755 {
6759 /* In the unlikely event that the member following the flexible
6760 array member is declared in a different class, point to it.
6761 Otherwise it should be obvious. */
6769 }
6770 }
6771 }
6774 /* Recursively check to make sure that any flexible array or zero-length
6775 array members of class T or its bases are valid (i.e., not the sole
6776 non-static data member of T and, if one exists, that it is the last
6777 non-static data member of T and its base classes. FMEM is expected
6778 to be initially null and is used internally by recursive calls to
6779 the function. Issue the appropriate diagnostics for the array member
6780 that fails the checks. */
6782 static void
6784 {
6785 /* Initialize the result of a search for flexible array and zero-length
6786 array members. Avoid doing any work if the most interesting FMEM data
6787 have already been populated. */
6794 /* Recursively check the primary base class first. */
6796 {
6799 }
6801 /* Recursively check the base classes. */
6804 {
6807 /* The primary base class was already checked above. */
6811 /* Virtual base classes are at the end. */
6815 /* Check the base class. */
6817 }
6820 {
6821 /* Check virtual base classes only once per derived class.
6822 I.e., this check is not performed recursively for base
6823 classes. */
6825 tree base_binfo;
6829 {
6830 /* Check the virtual base class. */
6834 }
6835 }
6837 /* Search the members of the current (derived) class. */
6841 {
6842 /* Issue diagnostics for invalid flexible and zero-length array members
6843 found in base classes or among the members of the current class. */
6845 }
6846 }
6848 /* Perform processing required when the definition of T (a class type)
6849 is complete. Diagnose invalid definitions of flexible array members
6850 and zero-size arrays. */
6852 void
6854 {
6855 tree x;
6856 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6860 {
6865 }
6867 /* If this type was previously laid out as a forward reference,
6868 make sure we lay it out again. */
6872 /* Make assumptions about the class; we'll reset the flags if
6873 necessary. */
6879 /* Do end-of-class semantic processing: checking the validity of the
6880 bases and members and add implicitly generated methods. */
6883 /* Find the key method. */
6885 {
6886 /* The Itanium C++ ABI permits the key method to be chosen when
6887 the class is defined -- even though the key method so
6888 selected may later turn out to be an inline function. On
6889 some systems (such as ARM Symbian OS) the key method cannot
6890 be determined until the end of the translation unit. On such
6891 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6892 will cause the class to be added to KEYED_CLASSES. Then, in
6893 finish_file we will determine the key method. */
6897 /* If a polymorphic class has no key method, we may emit the vtable
6898 in every translation unit where the class definition appears. If
6899 we're devirtualizing, we can look into the vtable even if we
6900 aren't emitting it. */
6903 }
6905 /* Layout the class itself. */
6908 /* We use the base type for trivial assignments, and hence it
6909 needs a mode. */
6912 /* With the layout complete, check for flexible array members and
6913 zero-length arrays that might overlap other members in the final
6914 layout. */
6919 /* If necessary, create the primary vtable for this class. */
6921 {
6922 /* We must enter these virtuals into the table. */
6926 /* Here we know enough to change the type of our virtual
6927 function table, but we will wait until later this function. */
6930 /* If we're warning about ABI tags, check the types of the new
6931 virtual functions. */
6935 }
6938 {
6940 tree fn;
6947 /* Add entries for virtual functions introduced by this class. */
6951 /* Set DECL_VINDEX for all functions declared in this class. */
6953 fn;
6955 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
6957 {
6961 /* A thunk. We should never be calling this entry directly
6962 from this vtable -- we'd use the entry for the non
6963 thunk base function. */
6967 }
6968 }
6975 /* Complete the rtl for any static member objects of the type we're
6976 working on. */
6983 /* Done with FIELDS...now decide whether to sort these for
6984 faster lookups later.
6986 We use a small number because most searches fail (succeeding
6987 ultimately as the search bores through the inheritance
6988 hierarchy), and we want this failure to occur quickly. */
6992 /* Complain if one of the field types requires lower visibility. */
6995 /* Make the rtl for any new vtables we have created, and unmark
6996 the base types we marked. */
6999 /* Build the VTT for T. */
7002 /* This warning does not make sense for Java classes, since they
7003 cannot have destructors. */
7008 "%q#T has virtual functions and accessible"
7016 /* Class layout, assignment of virtual table slots, etc., is now
7017 complete. Give the back end a chance to tweak the visibility of
7018 the class or perform any other required target modifications. */
7028 /* Finish debugging output for this type. */
7032 {
7035 {
7038 }
7040 {
7043 else
7044 {
7047 }
7049 }
7051 {
7053 "the type of the first field has a different ABI from the "
7056 }
7057 }
7058 }
7060 /* Insert FIELDS into T for the sorted case if the FIELDS count is
7061 equal to THRESHOLD or greater than THRESHOLD. */
7063 static void
7065 {
7068 {
7073 }
7074 }
7076 /* Insert lately defined enum ENUMTYPE into T for the sorted case. */
7078 void
7080 {
7083 {
7085 int n_fields
7096 }
7097 }
7099 /* When T was built up, the member declarations were added in reverse
7100 order. Rearrange them to declaration order. */
7102 void
7104 {
7105 tree next;
7106 tree prev;
7107 tree x;
7109 /* The following lists are all in reverse order. Put them in
7110 declaration order now. */
7114 /* Actually, for the TYPE_FIELDS, only the non TYPE_DECLs are in
7115 reverse order, so we can't just use nreverse. */
7120 {
7124 }
7126 {
7130 }
7131 }
7133 tree
7135 {
7138 /* Now that we've got all the field declarations, reverse everything
7139 as necessary. */
7145 /* Nadger the current location so that diagnostics point to the start of
7146 the struct, not the end. */
7150 {
7151 tree x;
7157 /* We need to emit an error message if this type was used as a parameter
7158 and it is an abstract type, even if it is a template. We construct
7159 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7160 account and we call complete_vars with this type, which will check
7161 the PARM_DECLS. Note that while the type is being defined,
7162 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7163 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7169 /* We need to add the target functions to the CLASSTYPE_METHOD_VEC if
7170 an enclosing scope is a template class, so that this function be
7171 found by lookup_fnfields_1 when the using declaration is not
7172 instantiated yet. */
7175 {
7180 }
7182 /* Remember current #pragma pack value. */
7185 /* Fix up any variants we've already built. */
7187 {
7192 }
7193 }
7194 else
7198 {
7199 /* People keep complaining that the compiler crashes on an invalid
7200 definition of initializer_list, so I guess we should explicitly
7201 reject it. What the compiler internals care about is that it's a
7202 template and has a pointer field followed by an integer field. */
7205 {
7208 {
7212 }
7213 }
7216 "definition of std::initializer_list does not match "
7218 }
7226 else
7230 /* Lambdas are defined by the LAMBDA_EXPR. */
7235 }
7236 \f
7237 /* Hash table to avoid endless recursion when handling references. */
7240 /* Return the dynamic type of INSTANCE, if known.
7241 Used to determine whether the virtual function table is needed
7242 or not.
7244 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7245 of our knowledge of its type. *NONNULL should be initialized
7246 before this function is called. */
7248 static tree
7250 {
7251 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7254 {
7258 else
7262 /* This is a call to a constructor, hence it's never zero. */
7264 {
7268 }
7272 /* This is a call to a constructor, hence it's never zero. */
7274 {
7278 }
7287 /* Propagate nonnull. */
7292 CASE_CONVERT:
7298 {
7299 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7300 with a real object -- given &p->f, p can still be null. */
7302 /* ??? Probably should check DECL_WEAK here. */
7305 }
7309 /* If this component is really a base class reference, then the field
7310 itself isn't definitive. */
7319 {
7323 }
7324 /* fall through... */
7329 {
7333 }
7335 {
7339 /* if we're in a ctor or dtor, we know our type. If
7340 current_class_ptr is set but we aren't in a function, we're in
7341 an NSDMI (and therefore a constructor). */
7346 {
7350 }
7351 }
7353 {
7354 /* We only need one hash table because it is always left empty. */
7356 fixed_type_or_null_ref_ht
7359 /* Reference variables should be references to objects. */
7363 /* Enter the INSTANCE in a table to prevent recursion; a
7364 variable's initializer may refer to the variable
7365 itself. */
7370 {
7371 tree type;
7380 }
7381 }
7386 }
7387 #undef RECUR
7388 }
7390 /* Return nonzero if the dynamic type of INSTANCE is known, and
7391 equivalent to the static type. We also handle the case where
7392 INSTANCE is really a pointer. Return negative if this is a
7393 ctor/dtor. There the dynamic type is known, but this might not be
7394 the most derived base of the original object, and hence virtual
7395 bases may not be laid out according to this type.
7397 Used to determine whether the virtual function table is needed
7398 or not.
7400 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7401 of our knowledge of its type. *NONNULL should be initialized
7402 before this function is called. */
7404 int
7406 {
7409 tree fixed;
7411 /* processing_template_decl can be false in a template if we're in
7412 instantiate_non_dependent_expr, but we still want to suppress
7413 this check. */
7415 {
7416 /* In a template we only care about the type of the result. */
7420 }
7430 }
7432 \f
7433 void
7435 {
7438 current_class_stack
7446 }
7448 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7450 static void
7452 {
7453 tree type;
7455 /* We are re-entering the same class we just left, so we don't
7456 have to search the whole inheritance matrix to find all the
7457 decls to bind again. Instead, we install the cached
7458 class_shadowed list and walk through it binding names. */
7461 /* Restore IDENTIFIER_TYPE_VALUE. */
7463 type;
7466 }
7468 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7469 appropriate for TYPE.
7471 So that we may avoid calls to lookup_name, we cache the _TYPE
7472 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7474 For multiple inheritance, we perform a two-pass depth-first search
7475 of the type lattice. */
7477 void
7479 {
7480 class_stack_node_t csn;
7484 /* Make sure there is enough room for the new entry on the stack. */
7486 {
7488 current_class_stack
7490 current_class_stack_size);
7491 }
7493 /* Insert a new entry on the class stack. */
7500 current_class_depth++;
7502 /* Now set up the new type. */
7508 /* By default, things in classes are private, while things in
7509 structures or unions are public. */
7511 ? access_private_node
7517 {
7518 /* Forcibly remove any old class remnants. */
7520 }
7526 else
7528 }
7530 /* When we exit a toplevel class scope, we save its binding level so
7531 that we can restore it quickly. Here, we've entered some other
7532 class, so we must invalidate our cache. */
7534 void
7536 {
7538 }
7540 /* Get out of the current class scope. If we were in a class scope
7541 previously, that is the one popped to. */
7543 void
7545 {
7548 current_class_depth--;
7554 }
7556 /* Mark the top of the class stack as hidden. */
7558 void
7560 {
7563 }
7565 /* Mark the top of the class stack as un-hidden. */
7567 void
7569 {
7572 }
7574 /* Returns 1 if the class type currently being defined is either T or
7575 a nested type of T. Returns the type from the current_class_stack,
7576 which might be equivalent to but not equal to T in case of
7577 constrained partial specializations. */
7579 tree
7581 {
7589 /* We start looking from 1 because entry 0 is from global scope,
7590 and has no type. */
7592 {
7593 tree c;
7596 else
7597 {
7601 }
7606 }
7608 }
7610 /* If either current_class_type or one of its enclosing classes are derived
7611 from T, return the appropriate type. Used to determine how we found
7612 something via unqualified lookup. */
7614 tree
7616 {
7619 /* The bases of a dependent type are unknown. */
7630 {
7635 }
7638 }
7640 /* Return the outermost enclosing class type that is still open, or
7641 NULL_TREE. */
7643 tree
7645 {
7652 {
7659 }
7661 }
7663 /* Returns the innermost class type which is not a lambda closure type. */
7665 tree
7667 {
7670 /* We start looking from 1 because entry 0 is from global scope,
7671 and has no type. */
7673 {
7674 tree c;
7677 else
7678 {
7682 }
7687 }
7689 }
7691 /* When entering a class scope, all enclosing class scopes' names with
7692 static meaning (static variables, static functions, types and
7693 enumerators) have to be visible. This recursive function calls
7694 pushclass for all enclosing class contexts until global or a local
7695 scope is reached. TYPE is the enclosed class. */
7697 void
7699 {
7700 /* A namespace might be passed in error cases, like A::B:C. */
7708 }
7710 /* Undoes a push_nested_class call. */
7712 void
7714 {
7720 }
7722 /* Returns the number of extern "LANG" blocks we are nested within. */
7724 int
7726 {
7728 }
7730 /* Set global variables CURRENT_LANG_NAME to appropriate value
7731 so that behavior of name-mangling machinery is correct. */
7733 void
7735 {
7739 {
7741 }
7743 {
7745 /* DECL_IGNORED_P is initially set for these types, to avoid clutter.
7746 (See record_builtin_java_type in decl.c.) However, that causes
7747 incorrect debug entries if these types are actually used.
7748 So we re-enable debug output after extern "Java". */
7757 }
7759 {
7761 }
7762 else
7764 }
7766 /* Get out of the current language scope. */
7768 void
7770 {
7772 }
7773 \f
7774 /* Type instantiation routines. */
7776 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7777 matches the TARGET_TYPE. If there is no satisfactory match, return
7778 error_mark_node, and issue an error & warning messages under
7779 control of FLAGS. Permit pointers to member function if FLAGS
7780 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7781 a template-id, and EXPLICIT_TARGS are the explicitly provided
7782 template arguments.
7784 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7785 is the base path used to reference those member functions. If
7786 the address is resolved to a member function, access checks will be
7787 performed and errors issued if appropriate. */
7789 static tree
7791 tree overload,
7792 tsubst_flags_t complain,
7794 tree explicit_targs,
7795 tree access_path)
7796 {
7797 /* Here's what the standard says:
7799 [over.over]
7801 If the name is a function template, template argument deduction
7802 is done, and if the argument deduction succeeds, the deduced
7803 arguments are used to generate a single template function, which
7804 is added to the set of overloaded functions considered.
7806 Non-member functions and static member functions match targets of
7807 type "pointer-to-function" or "reference-to-function." Nonstatic
7808 member functions match targets of type "pointer-to-member
7809 function;" the function type of the pointer to member is used to
7810 select the member function from the set of overloaded member
7811 functions. If a nonstatic member function is selected, the
7812 reference to the overloaded function name is required to have the
7813 form of a pointer to member as described in 5.3.1.
7815 If more than one function is selected, any template functions in
7816 the set are eliminated if the set also contains a non-template
7817 function, and any given template function is eliminated if the
7818 set contains a second template function that is more specialized
7819 than the first according to the partial ordering rules 14.5.5.2.
7820 After such eliminations, if any, there shall remain exactly one
7821 selected function. */
7824 /* We store the matches in a TREE_LIST rooted here. The functions
7825 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7826 interoperability with most_specialized_instantiation. */
7828 tree fn;
7829 tree target_fn_type;
7831 /* By the time we get here, we should be seeing only real
7832 pointer-to-member types, not the internal POINTER_TYPE to
7833 METHOD_TYPE representation. */
7839 /* Check that the TARGET_TYPE is reasonable. */
7844 /* This is OK, too. */
7847 /* This is OK, too. This comes from a conversion to reference
7848 type. */
7850 else
7851 {
7857 }
7859 /* Non-member functions and static member functions match targets of type
7860 "pointer-to-function" or "reference-to-function." Nonstatic member
7861 functions match targets of type "pointer-to-member-function;" the
7862 function type of the pointer to member is used to select the member
7863 function from the set of overloaded member functions.
7865 So figure out the FUNCTION_TYPE that we want to match against. */
7868 /* If we can find a non-template function that matches, we can just
7869 use it. There's no point in generating template instantiations
7870 if we're just going to throw them out anyhow. But, of course, we
7871 can only do this when we don't *need* a template function. */
7873 {
7874 tree fns;
7877 {
7881 /* We're not looking for templates just yet. */
7886 /* We're looking for a non-static member, and this isn't
7887 one, or vice versa. */
7890 /* Ignore functions which haven't been explicitly
7891 declared. */
7895 /* See if there's a match. */
7900 }
7901 }
7903 /* Now, if we've already got a match (or matches), there's no need
7904 to proceed to the template functions. But, if we don't have a
7905 match we need to look at them, too. */
7907 {
7908 tree target_arg_types;
7909 tree target_ret_type;
7910 tree fns;
7913 tree arg;
7927 {
7929 tree instantiation;
7930 tree targs;
7933 /* We're only looking for templates. */
7938 /* We're not looking for a non-static member, and this is
7939 one, or vice versa. */
7944 /* If the template has a deduced return type, don't expose it to
7945 template argument deduction. */
7949 /* Try to do argument deduction. */
7956 /* Instantiation failed. */
7959 /* Constraints must be satisfied. This is done before
7960 return type deduction since that instantiates the
7961 function. */
7965 /* And now force instantiation to do return type deduction. */
7967 {
7973 }
7975 /* See if there's a match. */
7980 }
7982 /* Now, remove all but the most specialized of the matches. */
7984 {
7989 NULL_TREE,
7990 NULL_TREE);
7991 }
7992 }
7994 /* Now we should have exactly one function in MATCHES. */
7996 {
7997 /* There were *no* matches. */
7999 {
8002 target_type);
8005 }
8007 }
8009 {
8010 /* There were too many matches. First check if they're all
8011 the same function. */
8016 /* For multi-versioned functions, more than one match is just fine and
8017 decls_match will return false as they are different. */
8025 {
8027 {
8030 target_type);
8032 /* Since print_candidates expects the functions in the
8033 TREE_VALUE slot, we flip them here. */
8038 }
8041 }
8042 }
8044 /* Good, exactly one match. Now, convert it to the correct type. */
8049 {
8057 {
8060 }
8061 }
8063 /* If a pointer to a function that is multi-versioned is requested, the
8064 pointer to the dispatcher function is returned instead. This works
8065 well because indirectly calling the function will dispatch the right
8066 function version at run-time. */
8068 {
8072 /* Mark all the versions corresponding to the dispatcher as used. */
8075 }
8077 /* If we're doing overload resolution purely for the purpose of
8078 determining conversion sequences, we should not consider the
8079 function used. If this conversion sequence is selected, the
8080 function will be marked as used at this point. */
8082 {
8083 /* Make =delete work with SFINAE. */
8088 }
8090 /* We could not check access to member functions when this
8091 expression was originally created since we did not know at that
8092 time to which function the expression referred. */
8094 {
8097 }
8101 else
8102 {
8103 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
8104 will mark the function as addressed, but here we must do it
8105 explicitly. */
8109 }
8110 }
8112 /* This function will instantiate the type of the expression given in
8113 RHS to match the type of LHSTYPE. If errors exist, then return
8114 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
8115 we complain on errors. If we are not complaining, never modify rhs,
8116 as overload resolution wants to try many possible instantiations, in
8117 the hope that at least one will work.
8119 For non-recursive calls, LHSTYPE should be a function, pointer to
8120 function, or a pointer to member function. */
8122 tree
8124 {
8131 {
8135 }
8138 {
8145 /* Microsoft allows `A::f' to be resolved to a
8146 pointer-to-member. */
8147 ;
8148 else
8149 {
8154 }
8155 }
8158 {
8161 }
8163 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
8164 deduce any type information. */
8166 {
8170 }
8172 /* There only a few kinds of expressions that may have a type
8173 dependent on overload resolution. */
8179 /* This should really only be used when attempting to distinguish
8180 what sort of a pointer to function we have. For now, any
8181 arithmetic operation which is not supported on pointers
8182 is rejected as an error. */
8185 {
8187 {
8193 /* Do not lose object's side effects. */
8197 }
8204 /* This can happen if we are forming a pointer-to-member for a
8205 member template. */
8208 /* Fall through. */
8211 {
8215 return
8219 }
8223 return
8227 access_path);
8230 {
8235 }
8242 }
8244 }
8245 \f
8246 /* Return the name of the virtual function pointer field
8247 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8248 this may have to look back through base types to find the
8249 ultimate field name. (For single inheritance, these could
8250 all be the same name. Who knows for multiple inheritance). */
8252 static tree
8254 {
8261 {
8267 }
8275 }
8277 void
8279 {
8286 {
8291 }
8292 }
8294 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8295 according to [class]:
8296 The class-name is also inserted
8297 into the scope of the class itself. For purposes of access checking,
8298 the inserted class name is treated as if it were a public member name. */
8300 void
8302 {
8305 tree saved_cas;
8320 }
8322 /* Returns 1 if TYPE contains only padding bytes. */
8324 int
8326 {
8334 }
8336 /* Returns true if TYPE contains no actual data, just various
8337 possible combinations of empty classes and possibly a vptr. */
8339 bool
8341 {
8343 {
8344 tree field;
8345 tree binfo;
8346 tree base_binfo;
8349 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8350 out, but we'd like to be able to check this before then. */
8364 }
8368 }
8370 /* Note that NAME was looked up while the current class was being
8371 defined and that the result of that lookup was DECL. */
8373 void
8375 {
8376 splay_tree names_used;
8378 /* If we're not defining a class, there's nothing to do. */
8384 /* If there's already a binding for this NAME, then we don't have
8385 anything to worry about. */
8398 }
8400 /* Note that NAME was declared (as DECL) in the current class. Check
8401 to see that the declaration is valid. */
8403 void
8405 {
8406 splay_tree names_used;
8407 splay_tree_node n;
8409 /* Look to see if we ever used this name. */
8410 names_used
8414 /* The C language allows members to be declared with a type of the same
8415 name, and the C++ standard says this diagnostic is not required. So
8416 allow it in extern "C" blocks unless predantic is specified.
8417 Allow it in all cases if -ms-extensions is specified. */
8423 {
8424 /* [basic.scope.class]
8426 A name N used in a class S shall refer to the same declaration
8427 in its context and when re-evaluated in the completed scope of
8428 S. */
8433 }
8434 }
8436 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8437 Secondary vtables are merged with primary vtables; this function
8438 will return the VAR_DECL for the primary vtable. */
8440 tree
8442 {
8443 tree decl;
8447 {
8450 }
8454 }
8457 /* Returns the binfo for the primary base of BINFO. If the resulting
8458 BINFO is a virtual base, and it is inherited elsewhere in the
8459 hierarchy, then the returned binfo might not be the primary base of
8460 BINFO in the complete object. Check BINFO_PRIMARY_P or
8461 BINFO_LOST_PRIMARY_P to be sure. */
8463 static tree
8465 {
8466 tree primary_base;
8473 }
8475 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8477 static int
8479 {
8483 }
8485 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8486 INDENT should be zero when called from the top level; it is
8487 incremented recursively. IGO indicates the next expected BINFO in
8488 inheritance graph ordering. */
8490 static tree
8493 tree binfo,
8494 tree igo,
8496 {
8498 tree base_binfo;
8506 {
8509 }
8524 {
8528 TFF_PLAIN_IDENTIFIER),
8530 }
8532 {
8535 }
8540 {
8544 {
8548 TFF_PLAIN_IDENTIFIER));
8549 }
8551 {
8555 TFF_PLAIN_IDENTIFIER));
8556 }
8558 {
8562 TFF_PLAIN_IDENTIFIER));
8563 }
8565 {
8569 TFF_PLAIN_IDENTIFIER));
8570 }
8574 }
8580 }
8582 /* Dump the BINFO hierarchy for T. */
8584 static void
8586 {
8598 }
8600 /* Debug interface to hierarchy dumping. */
8602 void
8604 {
8606 }
8608 static void
8610 {
8615 {
8617 }
8618 }
8620 static void
8622 {
8623 tree value;
8625 HOST_WIDE_INT elt;
8633 TFF_PLAIN_IDENTIFIER));
8640 }
8642 static void
8644 {
8652 {
8659 {
8664 }
8668 }
8669 }
8671 static void
8673 {
8681 {
8686 }
8687 }
8689 /* Dump a function or thunk and its thunkees. */
8691 static void
8693 {
8696 tree thunks;
8704 {
8714 else
8720 }
8724 }
8726 /* Dump the thunks for FN. */
8728 void
8730 {
8732 }
8734 /* Virtual function table initialization. */
8736 /* Create all the necessary vtables for T and its base classes. */
8738 static void
8740 {
8741 tree vbase;
8745 /* We lay out the primary and secondary vtables in one contiguous
8746 vtable. The primary vtable is first, followed by the non-virtual
8747 secondary vtables in inheritance graph order. */
8751 /* Then come the virtual bases, also in inheritance graph order. */
8753 {
8757 }
8761 }
8763 /* Initialize the vtable for BINFO with the INITS. */
8765 static void
8767 {
8768 tree decl;
8774 }
8776 /* Build the VTT (virtual table table) for T.
8777 A class requires a VTT if it has virtual bases.
8779 This holds
8780 1 - primary virtual pointer for complete object T
8781 2 - secondary VTTs for each direct non-virtual base of T which requires a
8782 VTT
8783 3 - secondary virtual pointers for each direct or indirect base of T which
8784 has virtual bases or is reachable via a virtual path from T.
8785 4 - secondary VTTs for each direct or indirect virtual base of T.
8787 Secondary VTTs look like complete object VTTs without part 4. */
8789 static void
8791 {
8792 tree type;
8793 tree vtt;
8794 tree index;
8797 /* Build up the initializers for the VTT. */
8802 /* If we didn't need a VTT, we're done. */
8806 /* Figure out the type of the VTT. */
8810 /* Now, build the VTT object itself. */
8813 /* Add the VTT to the vtables list. */
8818 }
8820 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8821 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8822 and CHAIN the vtable pointer for this binfo after construction is
8823 complete. VALUE can also be another BINFO, in which case we recurse. */
8825 static tree
8827 {
8828 tree vt;
8831 {
8837 else
8839 }
8842 }
8844 /* Data for secondary VTT initialization. */
8845 struct secondary_vptr_vtt_init_data
8846 {
8847 /* Is this the primary VTT? */
8850 /* Current index into the VTT. */
8851 tree index;
8853 /* Vector of initializers built up. */
8856 /* The type being constructed by this secondary VTT. */
8857 tree type_being_constructed;
8858 };
8860 /* Recursively build the VTT-initializer for BINFO (which is in the
8861 hierarchy dominated by T). INITS points to the end of the initializer
8862 list to date. INDEX is the VTT index where the next element will be
8863 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8864 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8865 for virtual bases of T. When it is not so, we build the constructor
8866 vtables for the BINFO-in-T variant. */
8868 static void
8871 {
8873 tree b;
8874 tree init;
8875 secondary_vptr_vtt_init_data data;
8878 /* We only need VTTs for subobjects with virtual bases. */
8882 /* We need to use a construction vtable if this is not the primary
8883 VTT. */
8885 {
8888 /* Record the offset in the VTT where this sub-VTT can be found. */
8890 }
8892 /* Add the address of the primary vtable for the complete object. */
8896 {
8899 }
8902 /* Recursively add the secondary VTTs for non-virtual bases. */
8907 /* Add secondary virtual pointers for all subobjects of BINFO with
8908 either virtual bases or reachable along a virtual path, except
8909 subobjects that are non-virtual primary bases. */
8919 /* data.inits might have grown as we added secondary virtual pointers.
8920 Make sure our caller knows about the new vector. */
8924 /* Add the secondary VTTs for virtual bases in inheritance graph
8925 order. */
8927 {
8932 }
8933 else
8934 /* Remove the ctor vtables we created. */
8936 }
8938 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8939 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8941 static tree
8943 {
8946 /* We don't care about bases that don't have vtables. */
8950 /* We're only interested in proper subobjects of the type being
8951 constructed. */
8955 /* We're only interested in bases with virtual bases or reachable
8956 via a virtual path from the type being constructed. */
8961 /* We're not interested in non-virtual primary bases. */
8965 /* Record the index where this secondary vptr can be found. */
8967 {
8972 {
8973 /* It's a primary virtual base, and this is not a
8974 construction vtable. Find the base this is primary of in
8975 the inheritance graph, and use that base's vtable
8976 now. */
8979 }
8980 }
8982 /* Add the initializer for the secondary vptr itself. */
8985 /* Advance the vtt index. */
8990 }
8992 /* Called from build_vtt_inits via dfs_walk. After building
8993 constructor vtables and generating the sub-vtt from them, we need
8994 to restore the BINFO_VTABLES that were scribbled on. DATA is the
8995 binfo of the base whose sub vtt was generated. */
8997 static tree
8999 {
9003 /* If this class has no vtable, none of its bases do. */
9007 /* This might be a primary base, so have no vtable in this
9008 hierarchy. */
9011 /* If we scribbled the construction vtable vptr into BINFO, clear it
9012 out now. */
9018 }
9020 /* Build the construction vtable group for BINFO which is in the
9021 hierarchy dominated by T. */
9023 static void
9025 {
9026 tree type;
9027 tree vtbl;
9028 tree id;
9029 tree vbase;
9032 /* See if we've already created this construction vtable group. */
9038 /* Build a version of VTBL (with the wrong type) for use in
9039 constructing the addresses of secondary vtables in the
9040 construction vtable group. */
9043 /* Don't export construction vtables from shared libraries. Even on
9044 targets that don't support hidden visibility, this tells
9045 can_refer_decl_in_current_unit_p not to assume that it's safe to
9046 access from a different compilation unit (bz 54314). */
9054 /* Add the vtables for each of our virtual bases using the vbase in T
9055 binfo. */
9057 vbase;
9059 {
9060 tree b;
9067 }
9069 /* Figure out the type of the construction vtable. */
9076 /* Initialize the construction vtable. */
9080 }
9082 /* Add the vtbl initializers for BINFO (and its bases other than
9083 non-virtual primaries) to the list of INITS. BINFO is in the
9084 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
9085 the constructor the vtbl inits should be accumulated for. (If this
9086 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
9087 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
9088 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
9089 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
9090 but are not necessarily the same in terms of layout. */
9092 static void
9094 tree orig_binfo,
9095 tree rtti_binfo,
9096 tree vtbl,
9097 tree t,
9099 {
9101 tree base_binfo;
9106 /* If it doesn't have a vptr, we don't do anything. */
9110 /* If we're building a construction vtable, we're not interested in
9111 subobjects that don't require construction vtables. */
9117 /* Build the initializers for the BINFO-in-T vtable. */
9120 /* Walk the BINFO and its bases. We walk in preorder so that as we
9121 initialize each vtable we can figure out at what offset the
9122 secondary vtable lies from the primary vtable. We can't use
9123 dfs_walk here because we need to iterate through bases of BINFO
9124 and RTTI_BINFO simultaneously. */
9126 {
9127 /* Skip virtual bases. */
9133 inits);
9134 }
9135 }
9137 /* Called from accumulate_vtbl_inits. Adds the initializers for the
9138 BINFO vtable to L. */
9140 static void
9142 tree orig_binfo,
9143 tree rtti_binfo,
9144 tree orig_vtbl,
9145 tree t,
9147 {
9154 {
9155 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9156 primary virtual base. If it is not the same primary in
9157 the hierarchy of T, we'll need to generate a ctor vtable
9158 for it, to place at its location in T. If it is the same
9159 primary, we still need a VTT entry for the vtable, but it
9160 should point to the ctor vtable for the base it is a
9161 primary for within the sub-hierarchy of RTTI_BINFO.
9163 There are three possible cases:
9165 1) We are in the same place.
9166 2) We are a primary base within a lost primary virtual base of
9167 RTTI_BINFO.
9168 3) We are primary to something not a base of RTTI_BINFO. */
9170 tree b;
9173 /* First, look through the bases we are primary to for RTTI_BINFO
9174 or a virtual base. */
9177 {
9182 }
9183 /* If we run out of primary links, keep looking down our
9184 inheritance chain; we might be an indirect primary. */
9188 found:
9190 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9191 base B and it is a base of RTTI_BINFO, this is case 2. In
9192 either case, we share our vtable with LAST, i.e. the
9193 derived-most base within B of which we are a primary. */
9196 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9197 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9198 binfo_ctor_vtable after everything's been set up. */
9201 /* Otherwise, this is case 3 and we get our own. */
9202 }
9209 {
9210 tree index;
9213 /* Add the initializer for this vtable. */
9217 /* Figure out the position to which the VPTR should point. */
9223 }
9226 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9227 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9228 straighten this out. */
9231 /* Throw away any unneeded intializers. */
9233 else
9234 /* For an ordinary vtable, set BINFO_VTABLE. */
9236 }
9240 /* Construct the initializer for BINFO's virtual function table. BINFO
9241 is part of the hierarchy dominated by T. If we're building a
9242 construction vtable, the ORIG_BINFO is the binfo we should use to
9243 find the actual function pointers to put in the vtable - but they
9244 can be overridden on the path to most-derived in the graph that
9245 ORIG_BINFO belongs. Otherwise,
9246 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9247 BINFO that should be indicated by the RTTI information in the
9248 vtable; it will be a base class of T, rather than T itself, if we
9249 are building a construction vtable.
9251 The value returned is a TREE_LIST suitable for wrapping in a
9252 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9253 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9254 number of non-function entries in the vtable.
9256 It might seem that this function should never be called with a
9257 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9258 base is always subsumed by a derived class vtable. However, when
9259 we are building construction vtables, we do build vtables for
9260 primary bases; we need these while the primary base is being
9261 constructed. */
9263 static void
9265 tree orig_binfo,
9266 tree t,
9267 tree rtti_binfo,
9270 {
9271 tree v;
9272 vtbl_init_data vid;
9274 tree vbinfo;
9278 /* Initialize VID. */
9286 /* The first vbase or vcall offset is at index -3 in the vtable. */
9289 /* Add entries to the vtable for RTTI. */
9292 /* Create an array for keeping track of the functions we've
9293 processed. When we see multiple functions with the same
9294 signature, we share the vcall offsets. */
9296 /* Add the vcall and vbase offset entries. */
9299 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9300 build_vbase_offset_vtbl_entries. */
9305 /* If the target requires padding between data entries, add that now. */
9307 {
9312 /* Move data entries into their new positions and add padding
9313 after the new positions. Iterate backwards so we don't
9314 overwrite entries that we would need to process later. */
9317 ix--)
9318 {
9326 {
9330 null_pointer_node);
9331 }
9332 }
9333 }
9338 /* The initializers for virtual functions were built up in reverse
9339 order. Straighten them out and add them to the running list in one
9340 step. */
9349 /* Go through all the ordinary virtual functions, building up
9350 initializers. */
9352 {
9353 tree delta;
9354 tree vcall_index;
9361 {
9365 {
9368 }
9370 }
9372 /* If the only definition of this function signature along our
9373 primary base chain is from a lost primary, this vtable slot will
9374 never be used, so just zero it out. This is important to avoid
9375 requiring extra thunks which cannot be generated with the function.
9377 We first check this in update_vtable_entry_for_fn, so we handle
9378 restored primary bases properly; we also need to do it here so we
9379 zero out unused slots in ctor vtables, rather than filling them
9380 with erroneous values (though harmless, apart from relocation
9381 costs). */
9386 {
9387 /* Pull the offset for `this', and the function to call, out of
9388 the list. */
9395 /* You can't call an abstract virtual function; it's abstract.
9396 So, we replace these functions with __pure_virtual. */
9398 {
9401 {
9403 abort_fndecl_addr
9407 }
9408 }
9409 /* Likewise for deleted virtuals. */
9411 {
9420 }
9421 else
9422 {
9424 {
9428 }
9429 /* Take the address of the function, considering it to be of an
9430 appropriate generic type. */
9434 /* Don't refer to a virtual destructor from a constructor
9435 vtable or a vtable for an abstract class, since destroying
9436 an object under construction is undefined behavior and we
9437 don't want it to be considered a candidate for speculative
9438 devirtualization. But do create the thunk for ABI
9439 compliance. */
9444 }
9445 }
9447 /* And add it to the chain of initializers. */
9449 {
9454 else
9456 {
9462 }
9463 }
9464 else
9466 }
9467 }
9469 /* Adds to vid->inits the initializers for the vbase and vcall
9470 offsets in BINFO, which is in the hierarchy dominated by T. */
9472 static void
9474 {
9475 tree b;
9477 /* If this is a derived class, we must first create entries
9478 corresponding to the primary base class. */
9483 /* Add the vbase entries for this base. */
9485 /* Add the vcall entries for this base. */
9487 }
9489 /* Returns the initializers for the vbase offset entries in the vtable
9490 for BINFO (which is part of the class hierarchy dominated by T), in
9491 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9492 where the next vbase offset will go. */
9494 static void
9496 {
9497 tree vbase;
9498 tree t;
9499 tree non_primary_binfo;
9501 /* If there are no virtual baseclasses, then there is nothing to
9502 do. */
9508 /* We might be a primary base class. Go up the inheritance hierarchy
9509 until we find the most derived class of which we are a primary base:
9510 it is the offset of that which we need to use. */
9513 {
9514 tree b;
9516 /* If we have reached a virtual base, then it must be a primary
9517 base (possibly multi-level) of vid->binfo, or we wouldn't
9518 have called build_vcall_and_vbase_vtbl_entries for it. But it
9519 might be a lost primary, so just skip down to vid->binfo. */
9521 {
9524 }
9530 }
9532 /* Go through the virtual bases, adding the offsets. */
9534 vbase;
9536 {
9537 tree b;
9538 tree delta;
9543 /* Find the instance of this virtual base in the complete
9544 object. */
9547 /* If we've already got an offset for this virtual base, we
9548 don't need another one. */
9553 /* Figure out where we can find this vbase offset. */
9562 /* The vbase offset had better be the same. */
9565 /* The next vbase will come at a more negative offset. */
9569 /* The initializer is the delta from BINFO to this virtual base.
9570 The vbase offsets go in reverse inheritance-graph order, and
9571 we are walking in inheritance graph order so these end up in
9572 the right order. */
9579 }
9580 }
9582 /* Adds the initializers for the vcall offset entries in the vtable
9583 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9584 to VID->INITS. */
9586 static void
9588 {
9589 /* We only need these entries if this base is a virtual base. We
9590 compute the indices -- but do not add to the vtable -- when
9591 building the main vtable for a class. */
9594 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9595 correspond to VID->DERIVED), we are building a primary
9596 construction virtual table. Since this is a primary
9597 virtual table, we do not need the vcall offsets for
9598 BINFO. */
9600 {
9601 /* We need a vcall offset for each of the virtual functions in this
9602 vtable. For example:
9604 class A { virtual void f (); };
9605 class B1 : virtual public A { virtual void f (); };
9606 class B2 : virtual public A { virtual void f (); };
9607 class C: public B1, public B2 { virtual void f (); };
9609 A C object has a primary base of B1, which has a primary base of A. A
9610 C also has a secondary base of B2, which no longer has a primary base
9611 of A. So the B2-in-C construction vtable needs a secondary vtable for
9612 A, which will adjust the A* to a B2* to call f. We have no way of
9613 knowing what (or even whether) this offset will be when we define B2,
9614 so we store this "vcall offset" in the A sub-vtable and look it up in
9615 a "virtual thunk" for B2::f.
9617 We need entries for all the functions in our primary vtable and
9618 in our non-virtual bases' secondary vtables. */
9620 /* If we are just computing the vcall indices -- but do not need
9621 the actual entries -- not that. */
9624 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9626 }
9627 }
9629 /* Build vcall offsets, starting with those for BINFO. */
9631 static void
9633 {
9635 tree primary_binfo;
9636 tree base_binfo;
9638 /* Don't walk into virtual bases -- except, of course, for the
9639 virtual base for which we are building vcall offsets. Any
9640 primary virtual base will have already had its offsets generated
9641 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9645 /* If BINFO has a primary base, process it first. */
9650 /* Add BINFO itself to the list. */
9653 /* Scan the non-primary bases of BINFO. */
9657 }
9659 /* Called from build_vcall_offset_vtbl_entries_r. */
9661 static void
9663 {
9664 /* Make entries for the rest of the virtuals. */
9665 tree orig_fn;
9667 /* The ABI requires that the methods be processed in declaration
9668 order. */
9670 orig_fn;
9674 }
9676 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9678 static void
9680 {
9682 tree vcall_offset;
9683 tree derived_entry;
9685 /* If there is already an entry for a function with the same
9686 signature as FN, then we do not need a second vcall offset.
9687 Check the list of functions already present in the derived
9688 class vtable. */
9690 {
9692 /* We only use one vcall offset for virtual destructors,
9693 even though there are two virtual table entries. */
9697 }
9699 /* If we are building these vcall offsets as part of building
9700 the vtable for the most derived class, remember the vcall
9701 offset. */
9703 {
9706 }
9708 /* The next vcall offset will be found at a more negative
9709 offset. */
9713 /* Keep track of this function. */
9717 {
9718 tree base;
9719 tree fn;
9721 /* Find the overriding function. */
9725 else
9726 {
9729 /* The vbase we're working on is a primary base of
9730 vid->binfo. But it might be a lost primary, so its
9731 BINFO_OFFSET might be wrong, so we just use the
9732 BINFO_OFFSET from vid->binfo. */
9738 vcall_offset);
9739 }
9740 /* Add the initializer to the vtable. */
9742 }
9743 }
9745 /* Return vtbl initializers for the RTTI entries corresponding to the
9746 BINFO's vtable. The RTTI entries should indicate the object given
9747 by VID->rtti_binfo. */
9749 static void
9751 {
9752 tree b;
9753 tree t;
9754 tree offset;
9755 tree decl;
9756 tree init;
9760 /* To find the complete object, we will first convert to our most
9761 primary base, and then add the offset in the vtbl to that value. */
9765 {
9766 tree primary_base;
9772 }
9776 /* The second entry is the address of the typeinfo object. */
9779 else
9782 /* Convert the declaration to a type that can be stored in the
9783 vtable. */
9787 /* Add the offset-to-top entry. It comes earlier in the vtable than
9788 the typeinfo entry. Convert the offset to look like a
9789 function pointer, so that we can put it in the vtable. */
9792 }
9794 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9795 accessibility. */
9797 bool
9799 {
9802 }
9804 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9806 bool
9808 {
9812 }
9814 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9815 class between them, if any. */
9817 tree
9819 {
9831 {
9834 }
9838 }