| blob | b447f7013ee067775604499deba53f8580d280ed |
1 /* Functions related to building classes and their related objects.
2 Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
4 Contributed by Michael Tiemann (tiemann@cygnus.com)
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to
20 the Free Software Foundation, 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
24 /* 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;
65 {
66 /* The base for which we're building initializers. */
67 tree binfo;
68 /* The type of the most-derived type. */
69 tree derived;
70 /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
71 unless ctor_vtbl_p is true. */
72 tree rtti_binfo;
73 /* The negative-index vtable initializers built up so far. These
74 are in order from least negative index to most negative index. */
75 tree inits;
76 /* The last (i.e., most negative) entry in INITS. */
78 /* The binfo for the virtual base for which we're building
79 vcall offset initializers. */
80 tree vbase;
81 /* The functions in vbase for which we have already provided vcall
82 offsets. */
83 varray_type fns;
84 /* The vtable index of the next vcall or vbase offset. */
85 tree index;
86 /* Nonzero if we are building the initializer for the primary
87 vtable. */
89 /* Nonzero if we are building the initializer for a construction
90 vtable. */
92 /* True when adding vcall offset entries to the vtable. False when
93 merely computing the indices. */
97 /* The type of a function passed to walk_subobject_offsets. */
100 /* The stack itself. This is a dynamically resized array. The
101 number of elements allocated is CURRENT_CLASS_STACK_SIZE. */
105 /* An array of all local classes present in this translation unit, in
106 declaration order. */
107 varray_type local_classes;
182 tree);
185 vtbl_init_data *);
205 splay_tree_key k2);
214 /* Macros for dfs walking during vtt construction. See
215 dfs_ctor_vtable_bases_queue_p, dfs_build_secondary_vptr_vtt_inits
216 and dfs_fixup_binfo_vtbls. */
217 #define VTT_TOP_LEVEL_P(NODE) TREE_UNSIGNED (NODE)
218 #define VTT_MARKED_BINFO_P(NODE) TREE_USED (NODE)
220 /* Variables shared between class.c and call.c. */
222 #ifdef GATHER_STATISTICS
231 #endif
233 /* Convert to or from a base subobject. EXPR is an expression of type
234 `A' or `A*', an expression of type `B' or `B*' is returned. To
235 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
236 the B base instance within A. To convert base A to derived B, CODE
237 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
238 In this latter case, A must not be a morally virtual base of B.
239 NONNULL is true if EXPR is known to be non-NULL (this is only
240 needed when EXPR is of pointer type). CV qualifiers are preserved
241 from EXPR. */
243 tree
245 tree expr,
246 tree binfo,
248 {
251 tree probe;
252 tree offset;
253 tree target_type;
255 tree ptr_target_type;
263 {
267 }
280 {
284 }
287 /* This must happen before the call to save_expr. */
300 {
301 /* Going via virtual base V_BINFO. We need the static offset
302 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
303 V_BINFO. That offset is an entry in D_BINFO's vtable. */
304 tree v_offset;
307 {
308 /* In a base member initializer, we cannot rely on
309 the vtable being set up. We have to use the vtt_parm. */
317 v_offset);
319 }
320 else
328 v_offset);
340 /* Negative fixed_type_p means this is a constructor or destructor;
341 virtual base layout is fixed in in-charge [cd]tors, but not in
342 base [cd]tors. */
346 v_offset,
348 else
350 }
354 target_type = cp_build_qualified_type
364 else
373 expr);
376 }
378 /* Convert OBJECT to the base TYPE. If CHECK_ACCESS is true, an error
379 message is emitted if TYPE is inaccessible. OBJECT is assumed to
380 be non-NULL. */
382 tree
384 {
385 tree binfo;
389 NULL);
394 }
396 /* EXPR is an expression with class type. BASE is a base class (a
397 BINFO) of that class type. Returns EXPR, converted to the BASE
398 type. This function assumes that EXPR is the most derived class;
399 therefore virtual bases can be found at their static offsets. */
401 tree
403 {
404 tree expr_type;
408 {
409 tree pointer_type;
418 }
421 }
423 \f
424 /* Virtual function things. */
426 static tree
428 {
448 }
450 /* Given an object INSTANCE, return an expression which yields the
451 vtable element corresponding to INDEX. There are many special
452 cases for INSTANCE which we take care of here, mainly to avoid
453 creating extra tree nodes when we don't have to. */
455 static tree
457 {
458 tree aref;
461 /* Try to figure out what a reference refers to, and
462 access its virtual function table directly. */
470 {
475 }
486 }
488 tree
490 {
497 }
499 /* Given an object INSTANCE, return an expression which yields a
500 function pointer corresponding to vtable element INDEX. */
502 tree
504 {
507 /* When using function descriptors, the address of the
508 vtable entry is treated as a function pointer. */
517 }
519 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
520 for the given TYPE. */
522 static tree
524 {
526 }
528 /* Return an IDENTIFIER_NODE for the name of the virtual table table
529 for TYPE. */
531 tree
533 {
535 }
537 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
538 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
539 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
541 static tree
543 {
544 tree decl;
547 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
548 now to avoid confusion in mangle_decl. */
558 /* At one time the vtable info was grabbed 2 words at a time. This
559 fails on sparc unless you have 8-byte alignment. (tiemann) */
566 }
568 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
569 or even complete. If this does not exist, create it. If COMPLETE is
570 nonzero, then complete the definition of it -- that will render it
571 impossible to actually build the vtable, but is useful to get at those
572 which are known to exist in the runtime. */
574 tree
576 {
577 tree decl;
586 {
589 }
592 }
594 /* Returns a copy of the BINFO_VIRTUALS list in BINFO. The
595 BV_VCALL_INDEX for each entry is cleared. */
597 static tree
599 {
600 tree copies;
601 tree t;
608 }
610 /* Build the primary virtual function table for TYPE. If BINFO is
611 non-NULL, build the vtable starting with the initial approximation
612 that it is the same as the one which is the head of the association
613 list. Returns a nonzero value if a new vtable is actually
614 created. */
616 static int
618 {
619 tree decl;
620 tree virtuals;
625 {
627 /* We have already created a vtable for this base, so there's
628 no need to do it again. */
635 }
636 else
637 {
640 }
642 #ifdef GATHER_STATISTICS
645 #endif
647 /* Initialize the association list for this type, based
648 on our first approximation. */
653 }
655 /* Give BINFO a new virtual function table which is initialized
656 with a skeleton-copy of its original initialization. The only
657 entry that changes is the `delta' entry, so we can really
658 share a lot of structure.
660 FOR_TYPE is the most derived type which caused this table to
661 be needed.
663 Returns nonzero if we haven't met BINFO before.
665 The order in which vtables are built (by calling this function) for
666 an object must remain the same, otherwise a binary incompatibility
667 can result. */
669 static int
671 {
673 /* We already created a vtable for this base. There's no need to
674 do it again. */
677 /* Remember that we've created a vtable for this BINFO, so that we
678 don't try to do so again. */
681 /* Make fresh virtual list, so we can smash it later. */
684 /* Secondary vtables are laid out as part of the same structure as
685 the primary vtable. */
688 }
690 /* Create a new vtable for BINFO which is the hierarchy dominated by
691 T. Return nonzero if we actually created a new vtable. */
693 static int
695 {
697 /* In this case, it is *type*'s vtable we are modifying. We start
698 with the approximation that its vtable is that of the
699 immediate base class. */
700 /* ??? This actually passes TYPE_BINFO (t), not the primary base binfo,
701 since we've updated DECL_CONTEXT (TYPE_VFIELD (t)) by now. */
703 t);
704 else
705 /* This is our very own copy of `basetype' to play with. Later,
706 we will fill in all the virtual functions that override the
707 virtual functions in these base classes which are not defined
708 by the current type. */
710 }
712 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
713 (which is in the hierarchy dominated by T) list FNDECL as its
714 BV_FN. DELTA is the required constant adjustment from the `this'
715 pointer where the vtable entry appears to the `this' required when
716 the function is actually called. */
718 static void
720 tree binfo,
721 tree fndecl,
722 tree delta,
724 {
725 tree v;
731 {
732 /* We need a new vtable for BINFO. */
734 {
735 /* If we really did make a new vtable, we also made a copy
736 of the BINFO_VIRTUALS list. Now, we have to find the
737 corresponding entry in that list. */
742 }
747 }
748 }
750 \f
751 /* Add method METHOD to class TYPE. If ERROR_P is true, we are adding
752 the method after the class has already been defined because a
753 declaration for it was seen. (Even though that is erroneous, we
754 add the method for improved error recovery.) */
756 void
758 {
762 tree method_vec;
767 /* Make a new method vector. We start with 8 entries. We must
768 allocate at least two (for constructors and destructors), and
769 we're going to end up with an assignment operator at some point
770 as well.
772 We could use a TREE_LIST for now, and convert it to a TREE_VEC
773 in finish_struct, but we would probably waste more memory
774 making the links in the list than we would by over-allocating
775 the size of the vector here. Furthermore, we would complicate
776 all the code that expects this to be a vector. */
782 /* Constructors and destructors go in special slots. */
787 else
788 {
791 /* See if we already have an entry with this name. */
793 {
801 {
805 /* If we need to move things up, see if there's
806 space. */
808 {
811 slot++;
812 }
814 }
817 }
820 {
821 /* We need a bigger method vector. */
823 tree new_vec;
825 /* In the non-error case, we are processing a class
826 definition. Double the size of the vector to give room
827 for new methods. */
830 /* In the error case, the vector is already complete. We
831 don't expect many errors, and the rest of the front-end
832 will get confused if there are empty slots in the vector. */
833 else
841 }
844 {
845 /* Type conversion operators have to come before ordinary
846 methods; add_conversions depends on this to speed up
847 looking for conversion operators. So, if necessary, we
848 slide some of the vector elements up. In theory, this
849 makes this algorithm O(N^2) but we don't expect many
850 conversion operators. */
853 else
855 {
859 /* There are no more entries in the vector, so we
860 can insert the new conversion operator here. */
864 /* We can insert the new function right at the
865 SLOTth position. */
867 }
872 /* There is nothing in the Ith slot, so we can avoid
873 moving anything. */
874 ;
875 else
876 {
877 /* We know the last slot in the vector is empty
878 because we know that at this point there's room
879 for a new function. */
884 }
885 }
886 }
889 /* TYPE is a template class. Don't issue any errors now; wait
890 until instantiation time to complain. */
891 ;
892 else
893 {
894 tree fns;
896 /* Check to see if we've already got this method. */
898 fns;
900 {
902 tree parms1;
903 tree parms2;
909 /* [over.load] Member function declarations with the
910 same name and the same parameter types cannot be
911 overloaded if any of them is a static member
912 function declaration.
914 [namespace.udecl] When a using-declaration brings names
915 from a base class into a derived class scope, member
916 functions in the derived class override and/or hide member
917 functions with the same name and parameter types in a base
918 class (rather than conflicting). */
922 /* Compare the quals on the 'this' parm. Don't compare
923 the whole types, as used functions are treated as
924 coming from the using class in overload resolution. */
931 /* For templates, the template parms must be identical. */
946 {
948 /* Defer to the local function. */
950 else
951 {
955 /* We don't call duplicate_decls here to merge
956 the declarations because that will confuse
957 things if the methods have inline
958 definitions. In particular, we will crash
959 while processing the definitions. */
961 }
962 }
963 }
964 }
966 /* Actually insert the new method. */
970 /* Add the new binding. */
975 }
977 /* Subroutines of finish_struct. */
979 /* Look through the list of fields for this struct, deleting
980 duplicates as we go. This must be recursive to handle
981 anonymous unions.
983 FIELD is the field which may not appear anywhere in FIELDS.
984 FIELD_PTR, if non-null, is the starting point at which
985 chained deletions may take place.
986 The value returned is the first acceptable entry found
987 in FIELDS.
989 Note that anonymous fields which are not of UNION_TYPE are
990 not duplicates, they are just anonymous fields. This happens
991 when we have unnamed bitfields, for example. */
993 static tree
995 {
996 tree x;
999 {
1006 }
1007 else
1008 {
1010 {
1012 {
1018 {
1021 else
1023 }
1024 }
1026 /* A using declaration is allowed to appear more than
1027 once. We'll prune these from the field list later, and
1028 handle_using_decl will complain about invalid multiple
1029 uses. */
1030 ;
1032 {
1039 x);
1042 {
1046 }
1049 {
1050 /* Hide tag decls. */
1057 x);
1058 }
1059 else
1063 else
1065 }
1066 }
1067 }
1069 }
1071 static void
1073 {
1074 tree x;
1077 }
1079 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1080 legit, otherwise return 0. */
1082 static int
1084 {
1085 tree elem;
1094 {
1096 {
1099 else
1102 }
1103 else
1104 {
1105 /* They're changing the access to the same thing they changed
1106 it to before. That's OK. */
1107 ;
1108 }
1109 }
1110 else
1111 {
1115 }
1117 }
1119 /* Process the USING_DECL, which is a member of T. */
1121 static void
1123 {
1126 tree access
1132 tree old_value;
1139 {
1142 }
1145 {
1148 }
1150 {
1153 }
1158 {
1161 }
1164 /* Ignore base type this came from. */
1169 {
1175 else
1177 }
1183 ;
1185 {
1187 /* It's OK to use functions from a base when there are functions with
1189 else
1190 {
1195 }
1196 }
1198 {
1202 }
1204 /* Make type T see field decl FDECL with access ACCESS.*/
1207 {
1210 }
1211 else
1213 }
1214 \f
1215 /* Run through the base clases of T, updating
1216 CANT_HAVE_DEFAULT_CTOR_P, CANT_HAVE_CONST_CTOR_P, and
1217 NO_CONST_ASN_REF_P. Also set flag bits in T based on properties of
1218 the bases. */
1220 static void
1225 {
1229 tree binfos;
1235 /* An aggregate cannot have baseclasses. */
1239 {
1240 tree base_binfo;
1241 tree basetype;
1243 /* Figure out what base we're looking at. */
1247 /* If the type of basetype is incomplete, then we already
1248 complained about that fact (and we should have fixed it up as
1249 well). */
1251 {
1253 /* The base type is of incomplete type. It is
1254 probably best to pretend that it does not
1255 exist. */
1263 }
1265 /* Effective C++ rule 14. We only need to check TYPE_POLYMORPHIC_P
1266 here because the case of virtual functions but non-virtual
1267 dtor is handled in finish_struct_1. */
1271 basetype);
1273 /* If the base class doesn't have copy constructors or
1274 assignment operators that take const references, then the
1275 derived class cannot have such a member automatically
1276 generated. */
1282 /* Similarly, if the base class doesn't have a default
1283 constructor, then the derived class won't have an
1284 automatically generated default constructor. */
1287 {
1291 basetype);
1292 }
1295 /* A virtual base does not effect nearly emptiness. */
1296 ;
1298 {
1300 /* And if there is more than one nearly empty base, then the
1301 derived class is not nearly empty either. */
1303 else
1304 /* Remember we've seen one. */
1306 }
1308 /* If the base class is not empty or nearly empty, then this
1309 class cannot be nearly empty. */
1312 /* A lot of properties from the bases also apply to the derived
1313 class. */
1326 }
1327 }
1329 /* Set BINFO_PRIMARY_BASE_OF for all binfos in the hierarchy
1330 dominated by TYPE that are primary bases. */
1332 static void
1334 {
1335 tree binfo;
1337 /* Walk the bases in inheritance graph order. */
1339 {
1346 else
1347 {
1349 /* A virtual binfo might have been copied from within
1350 another hierarchy. As we're about to use it as a primary
1351 base, make sure the offsets match. */
1353 {
1360 }
1361 }
1362 }
1363 }
1365 /* Make the BINFO the primary base of T. */
1367 static void
1369 {
1370 tree basetype;
1377 }
1379 /* Determine the primary class for T. */
1381 static void
1383 {
1385 tree vbases;
1386 tree type_binfo;
1388 /* If there are no baseclasses, there is certainly no primary base. */
1395 {
1400 {
1401 /* We prefer a non-virtual base, although a virtual one will
1402 do. */
1407 {
1410 }
1411 else
1412 {
1413 tree vfields;
1415 /* Only add unique vfields, and flatten them out as we go. */
1417 vfields;
1425 }
1426 }
1427 }
1432 /* Find the indirect primary bases - those virtual bases which are primary
1433 bases of something else in this hierarchy. */
1435 vbases;
1437 {
1440 /* See if this virtual base is an indirect primary base. To be so,
1441 it must be a primary base within the hierarchy of one of our
1442 direct bases. */
1444 {
1446 tree v;
1449 v;
1451 {
1457 {
1460 }
1461 }
1463 /* If we've discovered that this virtual base is an indirect
1464 primary base, then we can move on to the next virtual
1465 base. */
1468 }
1469 }
1471 /* A "nearly-empty" virtual base class can be the primary base
1472 class, if no non-virtual polymorphic base can be found. */
1474 {
1475 /* If not NULL, this is the best primary base candidate we have
1476 found so far. */
1478 tree base_binfo;
1480 /* Loop over the baseclasses. */
1482 base_binfo;
1484 {
1489 {
1490 /* If this is not an indirect primary base, then it's
1491 definitely our primary base. */
1493 {
1496 }
1498 /* If this is an indirect primary base, it still could be
1499 our primary base -- unless we later find there's another
1500 nearly-empty virtual base that isn't an indirect
1501 primary base. */
1504 }
1505 }
1507 /* If we've got a primary base, use it. */
1509 {
1513 }
1514 }
1516 /* Mark the primary base classes at this point. */
1518 }
1519 \f
1520 /* Set memoizing fields and bits of T (and its variants) for later
1521 use. */
1523 static void
1525 {
1528 /* Fix up variants (if any). */
1531 {
1532 /* These fields are in the _TYPE part of the node, not in
1533 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1544 /* Copy whatever these are holding today. */
1551 }
1554 /* For a class w/o baseclasses, `finish_struct' has set
1555 CLASS_TYPE_ABSTRACT_VIRTUALS correctly (by
1556 definition). Similarly for a class whose base classes do not
1557 have vtables. When neither of these is true, we might have
1558 removed abstract virtuals (by providing a definition), added
1559 some (by declaring new ones), or redeclared ones from a base
1560 class. We need to recalculate what's really an abstract virtual
1561 at this point (by looking in the vtables). */
1565 {
1566 /* Notice whether this class has type conversion functions defined. */
1569 tree basetype;
1572 {
1576 }
1577 }
1579 /* If this type has a copy constructor or a destructor, force its mode to
1580 be BLKmode, and force its TREE_ADDRESSABLE bit to be nonzero. This
1581 will cause it to be passed by invisible reference and prevent it from
1582 being returned in a register. */
1584 {
1585 tree variants;
1588 {
1591 }
1592 }
1593 }
1595 /* Issue warnings about T having private constructors, but no friends,
1596 and so forth.
1598 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
1599 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
1600 non-private static member functions. */
1602 static void
1604 {
1607 tree fn;
1610 /* If the class has friends, those entities might create and
1611 access instances, so we should not warn. */
1614 /* We will have warned when the template was declared; there's
1615 no need to warn on every instantiation. */
1617 /* There's no reason to even consider warning about this
1618 class. */
1621 /* We only issue one warning, if more than one applies, because
1622 otherwise, on code like:
1624 class A {
1625 // Oops - forgot `public:'
1626 A();
1627 A(const A&);
1628 ~A();
1629 };
1631 we warn several times about essentially the same problem. */
1633 /* Check to see if all (non-constructor, non-destructor) member
1634 functions are private. (Since there are no friends or
1635 non-private statics, we can't ever call any of the private member
1636 functions.) */
1638 /* We're not interested in compiler-generated methods; they don't
1639 provide any way to call private members. */
1641 {
1643 {
1645 /* A non-private static member function is just like a
1646 friend; it can create and invoke private member
1647 functions, and be accessed without a class
1648 instance. */
1652 /* Keep searching for a static member function. */
1653 }
1656 }
1659 {
1660 /* There are no non-private methods, and there's at least one
1661 private member function that isn't a constructor or
1662 destructor. (If all the private members are
1663 constructors/destructors we want to use the code below that
1664 issues error messages specifically referring to
1665 constructors/destructors.) */
1671 {
1674 }
1676 {
1679 }
1680 }
1682 /* Even if some of the member functions are non-private, the class
1683 won't be useful for much if all the constructors or destructors
1684 are private: such an object can never be created or destroyed. */
1686 {
1690 {
1692 t);
1694 }
1695 }
1698 {
1701 /* If a non-template class does not define a copy
1702 constructor, one is defined for it, enabling it to avoid
1703 this warning. For a template class, this does not
1704 happen, and so we would normally get a warning on:
1706 template <class T> class C { private: C(); };
1708 To avoid this asymmetry, we check TYPE_HAS_INIT_REF. All
1709 complete non-template or fully instantiated classes have this
1710 flag set. */
1713 else
1715 fn;
1717 {
1719 /* Ideally, we wouldn't count copy constructors (or, in
1720 fact, any constructor that takes an argument of the
1721 class type as a parameter) because such things cannot
1722 be used to construct an instance of the class unless
1723 you already have one. But, for now at least, we're
1724 more generous. */
1726 {
1729 }
1730 }
1733 {
1735 t);
1737 }
1738 }
1739 }
1742 gt_pointer_operator new_value;
1746 /* Comparison function to compare two TYPE_METHOD_VEC entries by name. */
1748 static int
1750 {
1763 }
1765 /* This routine compares two fields like method_name_cmp but using the
1766 pointer operator in resort_field_decl_data. */
1768 static int
1770 {
1779 {
1786 }
1788 }
1790 /* Resort TYPE_METHOD_VEC because pointers have been reordered. */
1792 void
1795 gt_pointer_operator new_value,
1797 {
1802 /* The type conversion ops have to live at the front of the vec, so we
1803 can't sort them. */
1805 {
1810 }
1812 {
1816 resort_method_name_cmp);
1817 }
1818 }
1820 /* Warn about duplicate methods in fn_fields. Also compact method
1821 lists so that lookup can be made faster.
1823 Data Structure: List of method lists. The outer list is a
1824 TREE_LIST, whose TREE_PURPOSE field is the field name and the
1825 TREE_VALUE is the DECL_CHAIN of the FUNCTION_DECLs. TREE_CHAIN
1826 links the entire list of methods for TYPE_METHODS. Friends are
1827 chained in the same way as member functions (? TREE_CHAIN or
1828 DECL_CHAIN), but they live in the TREE_TYPE field of the outer
1829 list. That allows them to be quickly deleted, and requires no
1830 extra storage.
1832 Sort methods that are not special (i.e., constructors, destructors,
1833 and type conversion operators) so that we can find them faster in
1834 search. */
1836 static void
1838 {
1839 tree fn_fields;
1840 tree method_vec;
1844 {
1845 /* Clear these for safety; perhaps some parsing error could set
1846 these incorrectly. */
1851 }
1857 /* First fill in entry 0 with the constructors, entry 1 with destructors,
1858 and the next few with type conversion operators (if any). */
1861 /* Clear out this flag. */
1865 /* We thought there was a destructor, but there wasn't. Some
1866 parse errors cause this anomalous situation. */
1869 /* Issue warnings about private constructors and such. If there are
1870 no methods, then some public defaults are generated. */
1873 /* Now sort the methods. */
1875 len--;
1878 /* The type conversion ops have to live at the front of the vec, so we
1879 can't sort them. */
1881 {
1886 }
1889 method_name_cmp);
1890 }
1892 /* Make BINFO's vtable have N entries, including RTTI entries,
1893 vbase and vcall offsets, etc. Set its type and call the backend
1894 to lay it out. */
1896 static void
1898 {
1899 tree atype;
1900 tree vtable;
1906 /* We may have to grow the vtable. */
1909 {
1913 }
1914 }
1916 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
1917 have the same signature. */
1919 int
1921 {
1922 /* One destructor overrides another if they are the same kind of
1923 destructor. */
1927 /* But a non-destructor never overrides a destructor, nor vice
1928 versa, nor do different kinds of destructors override
1929 one-another. For example, a complete object destructor does not
1930 override a deleting destructor. */
1935 {
1943 }
1945 }
1947 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
1948 subobject. */
1950 static bool
1952 {
1953 tree probe;
1956 {
1960 /* If we meet a virtual base, we can't follow the inheritance
1961 any more. See if the complete type of DERIVED contains
1962 such a virtual base. */
1966 }
1968 }
1971 /* The function for which we are trying to find a final overrider. */
1972 tree fn;
1973 /* The base class in which the function was declared. */
1974 tree declaring_base;
1975 /* The most derived class in the hierarchy. */
1976 tree most_derived_type;
1977 /* The candidate overriders. */
1978 tree candidates;
1979 /* Binfos which inherited virtually on the currrent path. */
1980 tree vpath;
1983 /* Called from find_final_overrider via dfs_walk. */
1985 static tree
1987 {
1991 {
1992 /* We've found a path to the declaring base. Walk the path from
1993 derived to base, looking for an overrider for FN. */
1996 /* Build the path, using the inheritance chain and record of
1997 virtual inheritance. */
1999 {
2004 {
2007 }
2008 else
2010 }
2011 /* Now walk path, looking for overrides. */
2013 {
2014 tree method = look_for_overrides_here
2018 {
2022 /* Remove any candidates overridden by this new function. */
2024 {
2025 /* If *CANDIDATE overrides METHOD, then METHOD
2026 cannot override anything else on the list. */
2029 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2032 else
2034 }
2036 /* Add the new function. */
2039 }
2040 }
2041 }
2044 }
2046 static tree
2048 {
2056 }
2058 static tree
2060 {
2067 }
2069 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2070 FN and whose TREE_VALUE is the binfo for the base where the
2071 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2072 DERIVED) is the base object in which FN is declared. */
2074 static tree
2076 {
2077 find_final_overrider_data ffod;
2079 /* Getting this right is a little tricky. This is valid:
2081 struct S { virtual void f (); };
2082 struct T { virtual void f (); };
2083 struct U : public S, public T { };
2085 even though calling `f' in `U' is ambiguous. But,
2087 struct R { virtual void f(); };
2088 struct S : virtual public R { virtual void f (); };
2089 struct T : virtual public R { virtual void f (); };
2090 struct U : public S, public T { };
2092 is not -- there's no way to decide whether to put `S::f' or
2093 `T::f' in the vtable for `R'.
2095 The solution is to look at all paths to BINFO. If we find
2096 different overriders along any two, then there is a problem. */
2107 dfs_find_final_overrider,
2108 dfs_find_final_overrider_post,
2109 dfs_find_final_overrider_q,
2112 /* If there was no winner, issue an error message. */
2114 {
2118 }
2121 }
2123 /* Return the index of the vcall offset for FN when TYPE is used as a
2124 virtual base. */
2126 static tree
2128 {
2129 tree v;
2136 /* There should always be an appropriate index. */
2140 }
2142 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2143 dominated by T. FN has been overridden in BINFO; VIRTUALS points to the
2144 corresponding position in the BINFO_VIRTUALS list. */
2146 static void
2149 {
2150 tree b;
2151 tree overrider;
2152 tree delta;
2153 tree virtual_base;
2154 tree first_defn;
2160 /* Find the nearest primary base (possibly binfo itself) which defines
2161 this function; this is the class the caller will convert to when
2162 calling FN through BINFO. */
2164 {
2169 /* The nearest definition is from a lost primary. */
2172 }
2175 /* Find the final overrider. */
2181 /* Check for adjusting covariant return types. */
2189 {
2190 /* If FN is a covariant thunk, we must figure out the adjustment
2191 to the final base FN was converting to. As OVERRIDER_TARGET might
2192 also be converting to the return type of FN, we have to
2193 combine the two conversions here. */
2197 {
2200 }
2201 else
2205 {
2206 /* There was no existing virtual thunk (which takes
2207 precidence). */
2208 tree thunk_binfo;
2209 base_kind kind;
2217 {
2221 {
2222 /* We convert via virtual base. Find the virtual
2223 base and adjust the fixed offset to be from there. */
2230 }
2232 /* There was an existing fixed offset, this must be
2233 from the base just converted to, and the base the
2234 FN was thunking to. */
2236 else
2238 }
2239 }
2242 /* Replace the overriding function with a covariant thunk. We
2243 will emit the overriding function in its own slot as
2244 well. */
2247 }
2248 else
2251 /* Assume that we will produce a thunk that convert all the way to
2252 the final overrider, and not to an intermediate virtual base. */
2255 /* See if we can convert to an intermediate virtual base first, and then
2256 use the vcall offset located there to finish the conversion. */
2258 {
2259 /* If we find the final overrider, then we can stop
2260 walking. */
2265 /* If we find a virtual base, and we haven't yet found the
2266 overrider, then there is a virtual base between the
2267 declaring base (first_defn) and the final overrider. */
2269 {
2272 }
2273 }
2276 {
2277 /* The ABI specifies that a covariant thunk includes a mangling
2278 for a this pointer adjustment. This-adjusting thunks that
2279 override a function from a virtual base have a vcall
2280 adjustment. When the virtual base in question is a primary
2281 virtual base, we know the adjustments are zero, (and in the
2282 non-covariant case, we would not use the thunk).
2283 Unfortunately we didn't notice this could happen, when
2284 designing the ABI and so never mandated that such a covariant
2285 thunk should be emitted. Because we must use the ABI mandated
2286 name, we must continue searching from the binfo where we
2287 found the most recent definition of the function, towards the
2288 primary binfo which first introduced the function into the
2289 vtable. If that enters a virtual base, we must use a vcall
2290 this-adjusting thunk. Bleah! */
2291 tree probe;
2294 {
2299 }
2301 /* Even if we find a virtual base, the correct delta is
2302 between the overrider and the binfo we're building a vtable
2303 for. */
2305 }
2307 /* Compute the constant adjustment to the `this' pointer. The
2308 `this' pointer, when this function is called, will point at BINFO
2309 (or one of its primary bases, which are at the same offset). */
2311 /* The `this' pointer needs to be adjusted from the declaration to
2312 the nearest virtual base. */
2316 /* If the nearest definition is in a lost primary, we don't need an
2317 entry in our vtable. Except possibly in a constructor vtable,
2318 if we happen to get our primary back. In that case, the offset
2319 will be zero, as it will be a primary base. */
2321 else
2322 /* The `this' pointer needs to be adjusted from pointing to
2323 BINFO to pointing at the base where the final overrider
2324 appears. */
2325 virtual_covariant:
2334 }
2336 /* Called from modify_all_vtables via dfs_walk. */
2338 static tree
2340 {
2342 primary base; we're not going to use that vtable anyhow.
2343 We do still need to do this for virtual primary bases, as they
2344 could become non-primary in a construction vtable. */
2346 /* Similarly, a base without a vtable needs no modification. */
2348 {
2350 tree virtuals;
2351 tree old_virtuals;
2356 /* Now, go through each of the virtual functions in the virtual
2357 function table for BINFO. Find the final overrider, and
2358 update the BINFO_VIRTUALS list appropriately. */
2361 virtuals;
2365 binfo,
2368 }
2373 }
2375 /* Update all of the primary and secondary vtables for T. Create new
2376 vtables as required, and initialize their RTTI information. Each
2377 of the functions in VIRTUALS is declared in T and may override a
2378 virtual function from a base class; find and modify the appropriate
2379 entries to point to the overriding functions. Returns a list, in
2380 declaration order, of the virtual functions that are declared in T,
2381 but do not appear in the primary base class vtable, and which
2382 should therefore be appended to the end of the vtable for T. */
2384 static tree
2386 {
2390 /* Update all of the vtables. */
2394 /* Add virtual functions not already in our primary vtable. These
2395 will be both those introduced by this class, and those overridden
2396 from secondary bases. It does not include virtuals merely
2397 inherited from secondary bases. */
2399 {
2404 {
2405 /* We don't need to adjust the `this' pointer when
2406 calling this function. */
2410 /* This is a function not already in our vtable. Keep it. */
2412 }
2413 else
2414 /* We've already got an entry for this function. Skip it. */
2416 }
2419 }
2421 /* Get the base virtual function declarations in T that have the
2422 indicated NAME. */
2424 static tree
2426 {
2427 tree methods;
2432 /* Find virtual functions in T with the indicated NAME. */
2436 methods;
2438 {
2444 }
2450 {
2453 base_fndecls);
2454 }
2457 }
2459 /* If this declaration supersedes the declaration of
2460 a method declared virtual in the base class, then
2461 mark this field as being virtual as well. */
2463 static void
2465 {
2467 /* In [temp.mem] we have:
2469 A specialization of a member function template does not
2470 override a virtual function from a base class. */
2476 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2477 the error_mark_node so that we know it is an overriding
2478 function. */
2482 {
2486 }
2487 }
2489 /* Warn about hidden virtual functions that are not overridden in t.
2490 We know that constructors and destructors don't apply. */
2492 void
2494 {
2499 /* We go through each separately named virtual function. */
2501 {
2502 tree fns;
2503 tree name;
2504 tree fndecl;
2505 tree base_fndecls;
2508 /* All functions in this slot in the CLASSTYPE_METHOD_VEC will
2509 have the same name. Figure out what name that is. */
2511 /* There are no possibly hidden functions yet. */
2513 /* Iterate through all of the base classes looking for possibly
2514 hidden functions. */
2516 {
2519 base_fndecls);
2520 }
2522 /* If there are no functions to hide, continue. */
2526 /* Remove any overridden functions. */
2528 {
2531 {
2535 /* If the method from the base class has the same
2536 signature as the method from the derived class, it
2537 has been overridden. */
2540 else
2542 }
2543 }
2545 /* Now give a warning for all base functions without overriders,
2546 as they are hidden. */
2548 {
2549 /* Here we know it is a hider, and no overrider exists. */
2554 }
2555 }
2556 }
2558 /* Check for things that are invalid. There are probably plenty of other
2559 things we should check for also. */
2561 static void
2563 {
2564 tree field;
2567 {
2575 {
2578 {
2579 /* We're generally only interested in entities the user
2580 declared, but we also find nested classes by noticing
2581 the TYPE_DECL that we create implicitly. You're
2582 allowed to put one anonymous union inside another,
2583 though, so we explicitly tolerate that. We use
2584 TYPE_ANONYMOUS_P rather than ANON_AGGR_TYPE_P so that
2585 we also allow unnamed types used for defining fields. */
2593 elt);
2596 {
2598 elt);
2600 }
2604 elt);
2607 elt);
2611 }
2612 }
2613 }
2614 }
2616 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2617 will be used later during class template instantiation.
2618 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2619 a non-static member data (FIELD_DECL), a member function
2620 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2621 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2622 When FRIEND_P is nonzero, T is either a friend class
2623 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2624 (FUNCTION_DECL, TEMPLATE_DECL). */
2626 void
2628 {
2629 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2634 }
2636 /* Create default constructors, assignment operators, and so forth for
2637 the type indicated by T, if they are needed.
2638 CANT_HAVE_DEFAULT_CTOR, CANT_HAVE_CONST_CTOR, and
2639 CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason, the
2640 class cannot have a default constructor, copy constructor taking a
2641 const reference argument, or an assignment operator taking a const
2642 reference, respectively. If a virtual destructor is created, its
2643 DECL is returned; otherwise the return value is NULL_TREE. */
2645 static void
2650 {
2651 tree default_fn;
2658 /* Destructor. */
2660 {
2664 /* If we couldn't make it work, then pretend we didn't need it. */
2667 else
2668 {
2674 }
2675 }
2676 else
2677 /* Any non-implicit destructor is non-trivial. */
2680 /* Default constructor. */
2682 {
2686 }
2688 /* Copy constructor. */
2690 {
2691 /* ARM 12.18: You get either X(X&) or X(const X&), but
2692 not both. --Chip */
2693 default_fn
2698 }
2700 /* Assignment operator. */
2702 {
2703 default_fn
2708 }
2710 /* Now, hook all of the new functions on to TYPE_METHODS,
2711 and add them to the CLASSTYPE_METHOD_VEC. */
2713 {
2716 }
2718 /* G++ 3.2 put the implicit destructor at the *beginning* of the
2719 list, which cause the destructor to be emitted in an incorrect
2720 location in the vtable. */
2722 else
2723 {
2726 "and may change in a future version of GCC due to implicit "
2728 t);
2731 }
2734 }
2736 /* Subroutine of finish_struct_1. Recursively count the number of fields
2737 in TYPE, including anonymous union members. */
2739 static int
2741 {
2742 tree x;
2745 {
2748 else
2750 }
2752 }
2754 /* Subroutine of finish_struct_1. Recursively add all the fields in the
2755 TREE_LIST FIELDS to the SORTED_FIELDS_TYPE elts, starting at offset IDX. */
2757 static int
2759 {
2760 tree x;
2762 {
2765 else
2767 }
2769 }
2771 /* FIELD is a bit-field. We are finishing the processing for its
2772 enclosing type. Issue any appropriate messages and set appropriate
2773 flags. */
2775 static void
2777 {
2781 /* Detect invalid bit-field type. */
2784 {
2787 }
2789 /* Detect and ignore out of range field width. */
2791 {
2794 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
2797 /* detect invalid field size. */
2800 else
2804 {
2806 field);
2808 }
2810 {
2813 }
2815 {
2818 }
2828 min_precision
2833 }
2835 /* Remove the bit-field width indicator so that the rest of the
2836 compiler does not treat that value as an initializer. */
2840 {
2843 }
2844 else
2845 {
2846 /* Non-bit-fields are aligned for their type. */
2849 }
2850 }
2852 /* FIELD is a non bit-field. We are finishing the processing for its
2853 enclosing type T. Issue any appropriate messages and set appropriate
2854 flags. */
2856 static void
2858 tree t,
2863 {
2866 /* An anonymous union cannot contain any fields which would change
2867 the settings of CANT_HAVE_CONST_CTOR and friends. */
2869 ;
2870 /* And, we don't set TYPE_HAS_CONST_INIT_REF, etc., for anonymous
2871 structs. So, we recurse through their fields here. */
2873 {
2874 tree fields;
2880 any_default_members);
2881 }
2882 /* Check members with class type for constructors, destructors,
2883 etc. */
2885 {
2886 /* Never let anything with uninheritable virtuals
2887 make it through without complaint. */
2891 {
2894 field);
2897 field);
2900 field);
2901 }
2902 else
2903 {
2909 }
2920 }
2922 {
2923 /* `build_class_init_list' does not recognize
2924 non-FIELD_DECLs. */
2928 }
2929 }
2931 /* Check the data members (both static and non-static), class-scoped
2932 typedefs, etc., appearing in the declaration of T. Issue
2933 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
2934 declaration order) of access declarations; each TREE_VALUE in this
2935 list is a USING_DECL.
2937 In addition, set the following flags:
2939 EMPTY_P
2940 The class is empty, i.e., contains no non-static data members.
2942 CANT_HAVE_DEFAULT_CTOR_P
2943 This class cannot have an implicitly generated default
2944 constructor.
2946 CANT_HAVE_CONST_CTOR_P
2947 This class cannot have an implicitly generated copy constructor
2948 taking a const reference.
2950 CANT_HAVE_CONST_ASN_REF
2951 This class cannot have an implicitly generated assignment
2952 operator taking a const reference.
2954 All of these flags should be initialized before calling this
2955 function.
2957 Returns a pointer to the end of the TYPE_FIELDs chain; additional
2958 fields can be added by adding to this chain. */
2960 static void
2965 {
2971 /* First, delete any duplicate fields. */
2974 /* Assume there are no access declarations. */
2976 /* Assume this class has no pointer members. */
2978 /* Assume none of the members of this class have default
2979 initializations. */
2983 {
2990 {
2992 {
2994 cp_warning_at
2996 x);
2997 else
2999 }
3002 /* We don't treat zero-width bitfields as making a class
3003 non-empty. */
3004 ;
3005 else
3006 {
3007 tree element_type;
3009 /* The class is non-empty. */
3011 /* The class is not even nearly empty. */
3013 /* If one of the data members contains an empty class,
3014 so does T. */
3019 }
3020 }
3023 {
3024 /* Prune the access declaration from the list of fields. */
3027 /* Save the access declarations for our caller. */
3030 /* Since we've reset *FIELD there's no reason to skip to the
3031 next field. */
3034 }
3040 /* If we've gotten this far, it's a data member, possibly static,
3041 or an enumerator. */
3045 /* ``A local class cannot have static data members.'' ARM 9.4 */
3049 /* Perform error checking that did not get done in
3050 grokdeclarator. */
3052 {
3054 x);
3057 }
3059 {
3063 }
3068 /* When this goes into scope, it will be a non-local reference. */
3075 {
3077 /* Unions cannot have static members. */
3081 }
3083 /* Now it can only be a FIELD_DECL. */
3088 /* If this is of reference type, check if it needs an init.
3089 Also do a little ANSI jig if necessary. */
3091 {
3096 /* ARM $12.6.2: [A member initializer list] (or, for an
3097 aggregate, initialization by a brace-enclosed list) is the
3098 only way to initialize nonstatic const and reference
3099 members. */
3106 }
3117 /* DR 148 now allows pointers to members (which are POD themselves),
3118 to be allowed in POD structs. */
3124 /* If any field is const, the structure type is pseudo-const. */
3126 {
3131 /* ARM $12.6.2: [A member initializer list] (or, for an
3132 aggregate, initialization by a brace-enclosed list) is the
3133 only way to initialize nonstatic const and reference
3134 members. */
3141 }
3142 /* A field that is pseudo-const makes the structure likewise. */
3144 {
3149 }
3151 /* Core issue 80: A nonstatic data member is required to have a
3152 different name from the class iff the class has a
3153 user-defined constructor. */
3157 /* We set DECL_C_BIT_FIELD in grokbitfield.
3158 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3161 else
3163 cant_have_const_ctor_p,
3164 cant_have_default_ctor_p,
3165 no_const_asn_ref_p,
3167 }
3169 /* Effective C++ rule 11. */
3172 {
3176 {
3180 }
3183 }
3186 /* Check anonymous struct/anonymous union fields. */
3189 /* We've built up the list of access declarations in reverse order.
3190 Fix that now. */
3192 }
3194 /* If TYPE is an empty class type, records its OFFSET in the table of
3195 OFFSETS. */
3197 static int
3199 {
3200 splay_tree_node n;
3205 /* Record the location of this empty object in OFFSETS. */
3213 type,
3217 }
3219 /* Returns nonzero if TYPE is an empty class type and there is
3220 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3222 static int
3224 {
3225 splay_tree_node n;
3226 tree t;
3231 /* Record the location of this empty object in OFFSETS. */
3241 }
3243 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3244 F for every subobject, passing it the type, offset, and table of
3245 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3246 be traversed.
3248 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3249 than MAX_OFFSET will not be walked.
3251 If F returns a nonzero value, the traversal ceases, and that value
3252 is returned. Otherwise, returns zero. */
3254 static int
3256 subobject_offset_fn f,
3257 tree offset,
3258 splay_tree offsets,
3259 tree max_offset,
3261 {
3265 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3266 stop. */
3271 {
3275 }
3278 {
3279 tree field;
3280 tree binfo;
3283 /* Avoid recursing into objects that are not interesting. */
3287 /* Record the location of TYPE. */
3292 /* Iterate through the direct base classes of TYPE. */
3296 {
3297 tree binfo_offset;
3312 offset,
3314 else
3315 {
3316 tree orig_binfo;
3317 /* We cannot rely on BINFO_OFFSET being set for the base
3318 class yet, but the offsets for direct non-virtual
3319 bases can be calculated by going back to the TYPE. */
3322 offset,
3324 }
3327 f,
3328 binfo_offset,
3329 offsets,
3330 max_offset,
3335 }
3338 {
3339 tree vbase;
3341 /* Iterate through the virtual base classes of TYPE. In G++
3342 3.2, we included virtual bases in the direct base class
3343 loop above, which results in incorrect results; the
3344 correct offsets for virtual bases are only known when
3345 working with the most derived type. */
3348 vbase;
3350 {
3353 f,
3355 offset,
3357 offsets,
3358 max_offset,
3362 }
3363 else
3364 {
3365 /* We still have to walk the primary base, if it is
3366 virtual. (If it is non-virtual, then it was walked
3367 above.) */
3371 {
3372 r = (walk_subobject_offsets
3377 }
3378 }
3379 }
3381 /* Iterate through the fields of TYPE. */
3384 {
3385 tree field_offset;
3389 else
3390 /* In G++ 3.2, DECL_FIELD_OFFSET was used. */
3394 f,
3396 offset,
3397 field_offset),
3398 offsets,
3399 max_offset,
3403 }
3404 }
3406 {
3409 tree index;
3411 /* Avoid recursing into objects that are not interesting. */
3416 /* Step through each of the elements in the array. */
3418 /* G++ 3.2 had an off-by-one error here. */
3423 {
3425 f,
3426 offset,
3427 offsets,
3428 max_offset,
3434 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3435 there's no point in iterating through the remaining
3436 elements of the array. */
3439 }
3440 }
3443 }
3445 /* Record all of the empty subobjects of TYPE (located at OFFSET) in
3446 OFFSETS. If VBASES_P is nonzero, virtual bases of TYPE are
3447 examined. */
3449 static void
3451 tree offset,
3452 splay_tree offsets,
3454 {
3457 }
3459 /* Returns nonzero if any of the empty subobjects of TYPE (located at
3460 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
3461 virtual bases of TYPE are examined. */
3463 static int
3465 tree offset,
3466 splay_tree offsets,
3468 {
3469 splay_tree_node max_node;
3471 /* Get the node in OFFSETS that indicates the maximum offset where
3472 an empty subobject is located. */
3474 /* If there aren't any empty subobjects, then there's no point in
3475 performing this check. */
3481 vbases_p);
3482 }
3484 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
3485 non-static data member of the type indicated by RLI. BINFO is the
3486 binfo corresponding to the base subobject, OFFSETS maps offsets to
3487 types already located at those offsets. This function determines
3488 the position of the DECL. */
3490 static void
3492 tree decl,
3493 tree binfo,
3494 splay_tree offsets)
3495 {
3498 tree type;
3501 {
3502 /* For the purposes of determining layout conflicts, we want to
3503 use the class type of BINFO; TREE_TYPE (DECL) will be the
3504 CLASSTYPE_AS_BASE version, which does not contain entries for
3505 zero-sized bases. */
3508 }
3509 else
3510 {
3513 }
3515 /* Try to place the field. It may take more than one try if we have
3516 a hard time placing the field without putting two objects of the
3517 same type at the same address. */
3519 {
3522 /* Place this field. */
3526 /* We have to check to see whether or not there is already
3527 something of the same type at the offset we're about to use.
3528 For example:
3530 struct S {};
3531 struct T : public S { int i; };
3532 struct U : public S, public T {};
3534 Here, we put S at offset zero in U. Then, we can't put T at
3535 offset zero -- its S component would be at the same address
3536 as the S we already allocated. So, we have to skip ahead.
3537 Since all data members, including those whose type is an
3538 empty class, have nonzero size, any overlap can happen only
3539 with a direct or indirect base-class -- it can't happen with
3540 a data member. */
3541 /* G++ 3.2 did not check for overlaps when placing a non-empty
3542 virtual base. */
3547 {
3548 /* Strip off the size allocated to this field. That puts us
3549 at the first place we could have put the field with
3550 proper alignment. */
3553 /* Bump up by the alignment required for the type. */
3554 rli->bitpos
3560 }
3561 else
3562 /* There was no conflict. We're done laying out this field. */
3564 }
3566 /* Now that we know where it will be placed, update its
3567 BINFO_OFFSET. */
3569 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
3570 this point because their BINFO_OFFSET is copied from another
3571 hierarchy. Therefore, we may not need to add the entire
3572 OFFSET. */
3577 }
3579 /* Returns true if TYPE is empty and OFFSET is nonzero. */
3581 static int
3583 tree offset,
3584 splay_tree offsets ATTRIBUTE_UNUSED)
3585 {
3587 }
3589 /* Layout the empty base BINFO. EOC indicates the byte currently just
3590 past the end of the class, and should be correctly aligned for a
3591 class of the type indicated by BINFO; OFFSETS gives the offsets of
3592 the empty bases allocated so far. T is the most derived
3593 type. Return nonzero iff we added it at the end. */
3595 static bool
3597 {
3598 tree alignment;
3602 /* This routine should only be used for empty classes. */
3613 /* This is an empty base class. We first try to put it at offset
3614 zero. */
3617 offsets,
3619 {
3620 /* That didn't work. Now, we move forward from the next
3621 available spot in the class. */
3625 {
3628 offsets,
3630 /* We finally found a spot where there's no overlap. */
3633 /* There's overlap here, too. Bump along to the next spot. */
3635 }
3636 }
3638 }
3640 /* Layout the the base given by BINFO in the class indicated by RLI.
3641 *BASE_ALIGN is a running maximum of the alignments of
3642 any base class. OFFSETS gives the location of empty base
3643 subobjects. T is the most derived type. Return nonzero if the new
3644 object cannot be nearly-empty. A new FIELD_DECL is inserted at
3645 *NEXT_FIELD, unless BINFO is for an empty base class.
3647 Returns the location at which the next field should be inserted. */
3652 {
3657 /* This error is now reported in xref_tag, thus giving better
3658 location information. */
3661 /* Place the base class. */
3663 {
3664 tree decl;
3666 /* The containing class is non-empty because it has a non-empty
3667 base class. */
3670 /* Create the FIELD_DECL. */
3680 /* Try to place the field. It may take more than one try if we
3681 have a hard time placing the field without putting two
3682 objects of the same type at the same address. */
3684 /* Add the new FIELD_DECL to the list of fields for T. */
3688 }
3689 else
3690 {
3691 tree eoc;
3694 /* On some platforms (ARM), even empty classes will not be
3695 byte-aligned. */
3699 /* A nearly-empty class "has no proper base class that is empty,
3700 not morally virtual, and at an offset other than zero." */
3702 {
3705 /* The check above (used in G++ 3.2) is insufficient because
3706 an empty class placed at offset zero might itself have an
3707 empty base at a nonzero offset. */
3709 empty_base_at_nonzero_offset_p,
3710 size_zero_node,
3714 {
3720 }
3721 }
3723 /* We do not create a FIELD_DECL for empty base classes because
3724 it might overlap some other field. We want to be able to
3725 create CONSTRUCTORs for the class by iterating over the
3726 FIELD_DECLs, and the back end does not handle overlapping
3727 FIELD_DECLs. */
3729 /* An empty virtual base causes a class to be non-empty
3730 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
3731 here because that was already done when the virtual table
3732 pointer was created. */
3733 }
3735 /* Record the offsets of BINFO and its base subobjects. */
3738 offsets,
3742 }
3744 /* Layout all of the non-virtual base classes. Record empty
3745 subobjects in OFFSETS. T is the most derived type. Return nonzero
3746 if the type cannot be nearly empty. The fields created
3747 corresponding to the base classes will be inserted at
3748 *NEXT_FIELD. */
3750 static void
3753 {
3754 /* Chain to hold all the new FIELD_DECLs which stand in for base class
3755 subobjects. */
3760 /* The primary base class is always allocated first. */
3765 /* Now allocate the rest of the bases. */
3767 {
3768 tree base_binfo;
3772 /* The primary base was already allocated above, so we don't
3773 need to allocate it again here. */
3777 /* Virtual bases are added at the end (a primary virtual base
3778 will have already been added). */
3784 }
3785 }
3787 /* Go through the TYPE_METHODS of T issuing any appropriate
3788 diagnostics, figuring out which methods override which other
3789 methods, and so forth. */
3791 static void
3793 {
3794 tree x;
3797 {
3798 /* If this was an evil function, don't keep it in class. */
3807 /* The name of the field is the original field name
3808 Save this in auxiliary field for later overloading. */
3810 {
3815 }
3816 }
3817 }
3819 /* FN is a constructor or destructor. Clone the declaration to create
3820 a specialized in-charge or not-in-charge version, as indicated by
3821 NAME. */
3823 static tree
3825 {
3826 tree parms;
3827 tree clone;
3829 /* Copy the function. */
3831 /* Remember where this function came from. */
3834 /* Reset the function name. */
3837 /* There's no pending inline data for this function. */
3840 /* And it hasn't yet been deferred. */
3843 /* The base-class destructor is not virtual. */
3845 {
3849 }
3851 /* If there was an in-charge parameter, drop it from the function
3852 type. */
3854 {
3855 tree basetype;
3856 tree parmtypes;
3857 tree exceptions;
3862 /* Skip the `this' parameter. */
3864 /* Skip the in-charge parameter. */
3866 /* And the VTT parm, in a complete [cd]tor. */
3870 /* If this is subobject constructor or destructor, add the vtt
3871 parameter. */
3875 parmtypes);
3878 exceptions);
3879 }
3881 /* Copy the function parameters. But, DECL_ARGUMENTS on a TEMPLATE_DECL
3882 aren't function parameters; those are the template parameters. */
3884 {
3886 /* Remove the in-charge parameter. */
3888 {
3892 }
3893 /* And the VTT parm, in a complete [cd]tor. */
3895 {
3898 else
3899 {
3903 }
3904 }
3907 {
3910 }
3911 }
3913 /* Create the RTL for this function. */
3917 /* Make it easy to find the CLONE given the FN. */
3921 /* If this is a template, handle the DECL_TEMPLATE_RESULT as well. */
3923 {
3924 tree result;
3931 }
3936 }
3938 /* Produce declarations for all appropriate clones of FN. If
3939 UPDATE_METHOD_VEC_P is nonzero, the clones are added to the
3940 CLASTYPE_METHOD_VEC as well. */
3942 void
3944 {
3945 tree clone;
3947 /* Avoid inappropriate cloning. */
3953 {
3954 /* For each constructor, we need two variants: an in-charge version
3955 and a not-in-charge version. */
3962 }
3963 else
3964 {
3967 /* For each destructor, we need three variants: an in-charge
3968 version, a not-in-charge version, and an in-charge deleting
3969 version. We clone the deleting version first because that
3970 means it will go second on the TYPE_METHODS list -- and that
3971 corresponds to the correct layout order in the virtual
3972 function table.
3974 For a non-virtual destructor, we do not build a deleting
3975 destructor. */
3977 {
3981 }
3988 }
3990 /* Note that this is an abstract function that is never emitted. */
3992 }
3994 /* DECL is an in charge constructor, which is being defined. This will
3995 have had an in class declaration, from whence clones were
3996 declared. An out-of-class definition can specify additional default
3997 arguments. As it is the clones that are involved in overload
3998 resolution, we must propagate the information from the DECL to its
3999 clones. */
4001 void
4003 {
4004 tree clone;
4008 {
4015 /* Skip the 'this' parameter. */
4031 {
4036 {
4037 /* A default parameter has been added. Adjust the
4038 clone's parameters. */
4041 tree type;
4046 {
4049 clone_parms);
4051 }
4054 clone_parms);
4061 }
4062 }
4064 }
4065 }
4067 /* For each of the constructors and destructors in T, create an
4068 in-charge and not-in-charge variant. */
4070 static void
4072 {
4073 tree fns;
4075 /* If for some reason we don't have a CLASSTYPE_METHOD_VEC, we bail
4076 out now. */
4084 }
4086 /* Remove all zero-width bit-fields from T. */
4088 static void
4090 {
4095 {
4100 else
4102 }
4103 }
4105 /* Returns TRUE iff we need a cookie when dynamically allocating an
4106 array whose elements have the indicated class TYPE. */
4108 static bool
4110 {
4111 tree fns;
4116 /* If there's a non-trivial destructor, we need a cookie. In order
4117 to iterate through the array calling the destructor for each
4118 element, we'll have to know how many elements there are. */
4122 /* If the usual deallocation function is a two-argument whose second
4123 argument is of type `size_t', then we have to pass the size of
4124 the array to the deallocation function, so we will need to store
4125 a cookie. */
4129 /* If there are no `operator []' members, or the lookup is
4130 ambiguous, then we don't need a cookie. */
4133 /* Loop through all of the functions. */
4135 {
4136 tree fn;
4137 tree second_parm;
4139 /* Select the current function. */
4141 /* See if this function is a one-argument delete function. If
4142 it is, then it will be the usual deallocation function. */
4146 /* Otherwise, if we have a two-argument function and the second
4147 argument is `size_t', it will be the usual deallocation
4148 function -- unless there is one-argument function, too. */
4152 }
4155 }
4157 /* Check the validity of the bases and members declared in T. Add any
4158 implicitly-generated functions (like copy-constructors and
4159 assignment operators). Compute various flag bits (like
4160 CLASSTYPE_NON_POD_T) for T. This routine works purely at the C++
4161 level: i.e., independently of the ABI in use. */
4163 static void
4165 {
4166 /* Nonzero if we are not allowed to generate a default constructor
4167 for this case. */
4169 /* Nonzero if the implicitly generated copy constructor should take
4170 a non-const reference argument. */
4172 /* Nonzero if the the implicitly generated assignment operator
4173 should take a non-const reference argument. */
4175 tree access_decls;
4177 /* By default, we use const reference arguments and generate default
4178 constructors. */
4183 /* Check all the base-classes. */
4187 /* Check all the data member declarations. */
4193 /* Check all the method declarations. */
4196 /* A nearly-empty class has to be vptr-containing; a nearly empty
4197 class contains just a vptr. */
4201 /* Do some bookkeeping that will guide the generation of implicitly
4202 declared member functions. */
4220 /* Synthesize any needed methods. Note that methods will be synthesized
4221 for anonymous unions; grok_x_components undoes that. */
4223 cant_have_const_ctor,
4224 no_const_asn_ref);
4226 /* Create the in-charge and not-in-charge variants of constructors
4227 and destructors. */
4230 /* Process the using-declarations. */
4234 /* Build and sort the CLASSTYPE_METHOD_VEC. */
4237 /* Figure out whether or not we will need a cookie when dynamically
4238 allocating an array of this type. */
4241 }
4243 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
4244 accordingly. If a new vfield was created (because T doesn't have a
4245 primary base class), then the newly created field is returned. It
4246 is not added to the TYPE_FIELDS list; it is the caller's
4247 responsibility to do that. Accumulate declared virtual functions
4248 on VIRTUALS_P. */
4250 static tree
4252 {
4253 tree fn;
4255 /* Collect the virtual functions declared in T. */
4259 {
4267 }
4269 /* If we couldn't find an appropriate base class, create a new field
4270 here. Even if there weren't any new virtual functions, we might need a
4271 new virtual function table if we're supposed to include vptrs in
4272 all classes that need them. */
4274 {
4275 /* We build this decl with vtbl_ptr_type_node, which is a
4276 `vtable_entry_type*'. It might seem more precise to use
4277 `vtable_entry_type (*)[N]' where N is the number of firtual
4278 functions. However, that would require the vtable pointer in
4279 base classes to have a different type than the vtable pointer
4280 in derived classes. We could make that happen, but that
4281 still wouldn't solve all the problems. In particular, the
4282 type-based alias analysis code would decide that assignments
4283 to the base class vtable pointer can't alias assignments to
4284 the derived class vtable pointer, since they have different
4285 types. Thus, in a derived class destructor, where the base
4286 class constructor was inlined, we could generate bad code for
4287 setting up the vtable pointer.
4289 Therefore, we use one type for all vtable pointers. We still
4290 use a type-correct type; it's just doesn't indicate the array
4291 bounds. That's better than using `void*' or some such; it's
4292 cleaner, and it let's the alias analysis code know that these
4293 stores cannot alias stores to void*! */
4294 tree field;
4305 /* This class is non-empty. */
4309 /* If there were any baseclasses, they can't possibly be at
4310 offset zero any more, because that's where the vtable
4311 pointer is. So, converting to a base class is going to
4312 take work. */
4316 }
4319 }
4321 /* Fixup the inline function given by INFO now that the class is
4322 complete. */
4324 static void
4326 {
4328 {
4331 {
4334 }
4335 }
4336 }
4338 /* Fixup the inline methods and friends in TYPE now that TYPE is
4339 complete. */
4341 static void
4343 {
4347 {
4352 else
4354 }
4356 /* Do inline member functions. */
4360 /* Do friends. */
4362 method;
4366 }
4368 /* Add OFFSET to all base types of BINFO which is a base in the
4369 hierarchy dominated by T.
4371 OFFSET, which is a type offset, is number of bytes. */
4373 static void
4375 {
4377 tree primary_binfo;
4379 /* Update BINFO's offset. */
4384 offset));
4386 /* Find the primary base class. */
4389 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
4390 downwards. */
4392 {
4393 tree base_binfo;
4395 /* On the first time through the loop, do the primary base.
4396 Because the primary base need not be an immediate base, we
4397 must handle the primary base specially. */
4399 {
4404 }
4405 else
4406 {
4408 /* Don't do the primary base twice. */
4411 }
4413 /* Skip virtual bases that aren't our canonical primary base. */
4419 }
4420 }
4422 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
4423 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
4424 empty subobjects of T. */
4426 static void
4428 {
4429 tree vbase;
4438 {
4439 /* In G++ 3.2, we incorrectly rounded the size before laying out
4440 the virtual bases. */
4442 #ifdef STRUCTURE_SIZE_BOUNDARY
4443 /* Packed structures don't need to have minimum size. */
4446 #endif
4450 }
4452 /* Find the last field. The artificial fields created for virtual
4453 bases will go after the last extant field to date. */
4458 /* Go through the virtual bases, allocating space for each virtual
4459 base that is not already a primary base class. These are
4460 allocated in inheritance graph order. */
4462 {
4467 {
4470 /* This virtual base is not a primary base of any class in the
4471 hierarchy, so we have to add space for it. */
4475 /* If the first virtual base might have been placed at a
4476 lower address, had we started from CLASSTYPE_SIZE, rather
4477 than TYPE_SIZE, issue a warning. There can be both false
4478 positives and false negatives from this warning in rare
4479 cases; to deal with all the possibilities would probably
4480 require performing both layout algorithms and comparing
4481 the results which is not particularly tractable. */
4483 && first_vbase
4484 && (tree_int_cst_lt
4488 bitsize_unit_node),
4490 warning ("offset of virtual base `%T' is not ABI-compliant and may change in a future version of GCC",
4491 basetype);
4494 }
4495 }
4496 }
4498 /* Returns the offset of the byte just past the end of the base class
4499 BINFO. */
4501 static tree
4503 {
4504 tree size;
4507 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
4508 allocate some space for it. It cannot have virtual bases, so
4509 TYPE_SIZE_UNIT is fine. */
4511 else
4515 }
4517 /* Returns the offset of the byte just past the end of the base class
4518 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
4519 only non-virtual bases are included. */
4521 static tree
4523 {
4525 tree binfo;
4526 tree offset;
4530 {
4541 }
4543 /* G++ 3.2 did not check indirect virtual bases. */
4546 binfo;
4548 {
4552 }
4555 }
4557 /* Warn about bases of T that are inaccessible because they are
4558 ambiguous. For example:
4560 struct S {};
4561 struct T : public S {};
4562 struct U : public S, public T {};
4564 Here, `(S*) new U' is not allowed because there are two `S'
4565 subobjects of U. */
4567 static void
4569 {
4571 tree vbases;
4572 tree basetype;
4574 /* Check direct bases. */
4576 {
4582 }
4584 /* Check for ambiguous virtual bases. */
4587 vbases;
4589 {
4595 }
4596 }
4598 /* Compare two INTEGER_CSTs K1 and K2. */
4600 static int
4602 {
4604 }
4606 /* Increase the size indicated in RLI to account for empty classes
4607 that are "off the end" of the class. */
4609 static void
4611 {
4612 tree eoc;
4613 tree rli_size;
4615 /* It might be the case that we grew the class to allocate a
4616 zero-sized base class. That won't be reflected in RLI, yet,
4617 because we are willing to overlay multiple bases at the same
4618 offset. However, now we need to make sure that RLI is big enough
4619 to reflect the entire class. */
4625 {
4627 rli->bitpos
4636 }
4637 }
4639 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
4640 BINFO_OFFSETs for all of the base-classes. Position the vtable
4641 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
4643 static void
4645 {
4646 tree non_static_data_members;
4647 tree field;
4648 tree vptr;
4649 record_layout_info rli;
4650 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
4651 types that appear at that offset. */
4652 splay_tree empty_base_offsets;
4653 /* True if the last field layed out was a bit-field. */
4655 /* The location at which the next field should be inserted. */
4657 /* T, as a base class. */
4658 tree base_t;
4660 /* Keep track of the first non-static data member. */
4663 /* Start laying out the record. */
4666 /* If possible, we reuse the virtual function table pointer from one
4667 of our base classes. */
4670 /* Create a pointer to our virtual function table. */
4673 /* The vptr is always the first thing in the class. */
4675 {
4680 }
4681 else
4684 /* Build FIELD_DECLs for all of the non-virtual base-types. */
4689 /* Layout the non-static data members. */
4691 {
4692 tree type;
4693 tree padding;
4695 /* We still pass things that aren't non-static data members to
4696 the back-end, in case it wants to do something with them. */
4698 {
4700 /* If the static data member has incomplete type, keep track
4701 of it so that it can be completed later. (The handling
4702 of pending statics in finish_record_layout is
4703 insufficient; consider:
4705 struct S1;
4706 struct S2 { static S1 s1; };
4708 At this point, finish_record_layout will be called, but
4709 S1 is still incomplete.) */
4713 }
4719 /* If this field is a bit-field whose width is greater than its
4720 type, then there are some special rules for allocating
4721 it. */
4724 {
4725 integer_type_kind itk;
4726 tree integer_type;
4728 /* We must allocate the bits as if suitably aligned for the
4729 longest integer type that fits in this many bits. type
4730 of the field. Then, we are supposed to use the left over
4731 bits as additional padding. */
4737 /* ITK now indicates a type that is too large for the
4738 field. We have to back up by one to find the largest
4739 type that fits. */
4742 /* Figure out how much additional padding is required. GCC
4743 3.2 always created a padding field, even if it had zero
4744 width. */
4747 {
4749 /* In a union, the padding field must have the full width
4750 of the bit-field; all fields start at offset zero. */
4752 else
4753 {
4756 "ABI-compliant and may change in a future "
4758 t);
4761 }
4762 }
4763 #ifdef PCC_BITFIELD_TYPE_MATTERS
4764 /* An unnamed bitfield does not normally affect the
4765 alignment of the containing class on a target where
4766 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
4767 make any exceptions for unnamed bitfields when the
4768 bitfields are longer than their types. Therefore, we
4769 temporarily give the field a name. */
4771 {
4774 }
4775 #endif
4780 empty_base_offsets);
4783 /* Now that layout has been performed, set the size of the
4784 field to the size of its declared type; the rest of the
4785 field is effectively invisible. */
4787 }
4788 else
4790 empty_base_offsets);
4792 /* Remember the location of any empty classes in FIELD. */
4796 empty_base_offsets,
4799 /* If a bit-field does not immediately follow another bit-field,
4800 and yet it starts in the middle of a byte, we have failed to
4801 comply with the ABI. */
4804 && !last_field_was_bitfield
4807 bitsize_unit_node)))
4808 cp_warning_at ("offset of `%D' is not ABI-compliant and may change in a future version of GCC",
4809 field);
4811 /* G++ used to use DECL_FIELD_OFFSET as if it were the byte
4812 offset of the field. */
4818 "classes to be placed at different locations in a "
4820 field);
4822 /* If we needed additional padding after this field, add it
4823 now. */
4825 {
4826 tree padding_field;
4829 NULL_TREE,
4830 char_type_node);
4835 NULL_TREE,
4836 empty_base_offsets);
4837 }
4840 }
4843 {
4844 /* Make sure that we are on a byte boundary so that the size of
4845 the class without virtual bases will always be a round number
4846 of bytes. */
4849 }
4851 /* G++ 3.2 does not allow virtual bases to be overlaid with tail
4852 padding. */
4856 /* Delete all zero-width bit-fields from the list of fields. Now
4857 that the type is laid out they are no longer important. */
4860 /* Create the version of T used for virtual bases. We do not use
4861 make_aggr_type for this version; this is an artificial type. For
4862 a POD type, we just reuse T. */
4864 {
4867 /* Set the size and alignment for the new type. In G++ 3.2, all
4868 empty classes were considered to have size zero when used as
4869 base classes. */
4871 {
4877 t);
4878 }
4879 else
4880 {
4881 tree eoc;
4883 /* If the ABI version is not at least two, and the last
4884 field was a bit-field, RLI may not be on a byte
4885 boundary. In particular, rli_size_unit_so_far might
4886 indicate the last complete byte, while rli_size_so_far
4887 indicates the total number of bits used. Therefore,
4888 rli_size_so_far, rather than rli_size_unit_so_far, is
4889 used to compute TYPE_SIZE_UNIT. */
4897 eoc);
4904 }
4908 /* Copy the fields from T. */
4912 {
4921 }
4923 /* Record the base version of the type. */
4926 }
4927 else
4930 /* Every empty class contains an empty class. */
4934 /* Set the TYPE_DECL for this type to contain the right
4935 value for DECL_OFFSET, so that we can use it as part
4936 of a COMPONENT_REF for multiple inheritance. */
4939 /* Now fix up any virtual base class types that we left lying
4940 around. We must get these done before we try to lay out the
4941 virtual function table. As a side-effect, this will remove the
4942 base subobject fields. */
4945 /* Make sure that empty classes are reflected in RLI at this
4946 point. */
4949 /* Make sure not to create any structures with zero size. */
4954 /* Let the back-end lay out the type. */
4957 /* Warn about bases that can't be talked about due to ambiguity. */
4960 /* Clean up. */
4962 }
4964 /* Returns the virtual function with which the vtable for TYPE is
4965 emitted, or NULL_TREE if that heuristic is not applicable to TYPE. */
4967 static tree
4969 {
4970 tree method;
4973 || processing_template_decl
4986 }
4988 /* Perform processing required when the definition of T (a class type)
4989 is complete. */
4991 void
4993 {
4994 tree x;
4995 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
4998 tree vfield;
5001 {
5004 else
5008 }
5010 /* If this type was previously laid out as a forward reference,
5011 make sure we lay it out again. */
5018 /* Make assumptions about the class; we'll reset the flags if
5019 necessary. */
5024 /* Do end-of-class semantic processing: checking the validity of the
5025 bases and members and add implicitly generated methods. */
5028 /* Find the key method */
5030 {
5033 /* If a polymorphic class has no key method, we may emit the vtable
5034 in every translation unit where the class definition appears. */
5037 }
5039 /* Layout the class itself. */
5042 /* Make sure that we get our own copy of the vfield FIELD_DECL. */
5045 {
5051 /* The vtable better be at the start. */
5060 }
5061 else
5066 /* If we created a new vtbl pointer for this class, add it to the
5067 list. */
5072 /* If necessary, create the primary vtable for this class. */
5074 {
5075 /* We must enter these virtuals into the table. */
5079 /* Here we know enough to change the type of our virtual
5080 function table, but we will wait until later this function. */
5082 }
5085 {
5087 tree fn;
5096 /* Add entries for virtual functions introduced by this class. */
5099 /* Set DECL_VINDEX for all functions declared in this class. */
5101 fn;
5103 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
5105 {
5109 /* A thunk. We should never be calling this entry directly
5110 from this vtable -- we'd use the entry for the non
5111 thunk base function. */
5115 }
5116 }
5120 /* Complete the rtl for any static member objects of the type we're
5121 working on. */
5127 /* Done with FIELDS...now decide whether to sort these for
5128 faster lookups later.
5130 We use a small number because most searches fail (succeeding
5131 ultimately as the search bores through the inheritance
5132 hierarchy), and we want this failure to occur quickly. */
5136 {
5142 field_decl_cmp);
5146 }
5149 {
5154 /* Mark the fact that constructor for T could affect anybody
5155 inheriting from T who wants to initialize vtables for
5156 VFIELDS's type. */
5159 }
5161 /* Make the rtl for any new vtables we have created, and unmark
5162 the base types we marked. */
5165 /* Build the VTT for T. */
5181 /* Finish debugging output for this type. */
5183 }
5185 /* When T was built up, the member declarations were added in reverse
5186 order. Rearrange them to declaration order. */
5188 void
5190 {
5191 tree next;
5192 tree prev;
5193 tree x;
5195 /* The following lists are all in reverse order. Put them in
5196 declaration order now. */
5200 /* Actually, for the TYPE_FIELDS, only the non TYPE_DECLs are in
5201 reverse order, so we can't just use nreverse. */
5206 {
5210 }
5212 {
5216 }
5217 }
5219 tree
5221 {
5224 /* Now that we've got all the field declarations, reverse everything
5225 as necessary. */
5230 /* Nadger the current location so that diagnostics point to the start of
5231 the struct, not the end. */
5235 {
5238 }
5239 else
5248 else
5255 }
5256 \f
5257 /* Return the dynamic type of INSTANCE, if known.
5258 Used to determine whether the virtual function table is needed
5259 or not.
5261 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5262 of our knowledge of its type. *NONNULL should be initialized
5263 before this function is called. */
5265 static tree
5267 {
5269 {
5273 else
5278 /* This is a call to a constructor, hence it's never zero. */
5280 {
5284 }
5288 /* This is a call to a constructor, hence it's never zero. */
5290 {
5294 }
5305 /* Propagate nonnull. */
5325 {
5329 }
5330 /* fall through... */
5335 {
5339 }
5341 {
5345 /* if we're in a ctor or dtor, we know our type. */
5349 {
5353 }
5354 }
5356 {
5357 /* Reference variables should be references to objects. */
5361 /* DECL_VAR_MARKED_P is used to prevent recursion; a
5362 variable's initializer may refer to the variable
5363 itself. */
5367 {
5368 tree type;
5374 }
5375 }
5380 }
5381 }
5383 /* Return nonzero if the dynamic type of INSTANCE is known, and
5384 equivalent to the static type. We also handle the case where
5385 INSTANCE is really a pointer. Return negative if this is a
5386 ctor/dtor. There the dynamic type is known, but this might not be
5387 the most derived base of the original object, and hence virtual
5388 bases may not be layed out according to this type.
5390 Used to determine whether the virtual function table is needed
5391 or not.
5393 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5394 of our knowledge of its type. *NONNULL should be initialized
5395 before this function is called. */
5397 int
5399 {
5411 }
5413 \f
5414 void
5416 {
5419 current_class_stack
5426 }
5428 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
5429 appropriate for TYPE.
5431 If MODIFY is 1, we set IDENTIFIER_CLASS_VALUE's of names
5432 which can be seen locally to the class. They are shadowed by
5433 any subsequent local declaration (including parameter names).
5435 If MODIFY is 2, we set IDENTIFIER_CLASS_VALUE's of names
5436 which have static meaning (i.e., static members, static
5437 member functions, enum declarations, etc).
5439 If MODIFY is 3, we set IDENTIFIER_CLASS_VALUE of names
5440 which can be seen locally to the class (as in 1), but
5441 know that we are doing this for declaration purposes
5442 (i.e. friend foo::bar (int)).
5444 So that we may avoid calls to lookup_name, we cache the _TYPE
5445 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
5447 For multiple inheritance, we perform a two-pass depth-first search
5448 of the type lattice. The first pass performs a pre-order search,
5449 marking types after the type has had its fields installed in
5450 the appropriate IDENTIFIER_CLASS_VALUE slot. The second pass merely
5451 unmarks the marked types. If a field or member function name
5452 appears in an ambiguous way, the IDENTIFIER_CLASS_VALUE of
5453 that name becomes `error_mark_node'. */
5455 void
5457 {
5460 /* Make sure there is enough room for the new entry on the stack. */
5462 {
5464 current_class_stack
5466 current_class_stack_size
5468 }
5470 /* Insert a new entry on the class stack. */
5475 current_class_depth++;
5477 /* Now set up the new type. */
5483 /* By default, things in classes are private, while things in
5484 structures or unions are public. */
5486 ? access_private_node
5493 {
5494 /* Forcibly remove any old class remnants. */
5496 }
5498 /* If we're about to enter a nested class, clear
5499 IDENTIFIER_CLASS_VALUE for the enclosing classes. */
5506 {
5509 else
5510 {
5511 tree item;
5513 /* We are re-entering the same class we just left, so we
5514 don't have to search the whole inheritance matrix to find
5515 all the decls to bind again. Instead, we install the
5516 cached class_shadowed list, and walk through it binding
5517 names and setting up IDENTIFIER_TYPE_VALUEs. */
5520 {
5527 }
5529 }
5532 }
5533 }
5535 /* When we exit a toplevel class scope, we save the
5536 IDENTIFIER_CLASS_VALUEs so that we can restore them quickly if we
5537 reenter the class. Here, we've entered some other class, so we
5538 must invalidate our cache. */
5540 void
5542 {
5543 tree t;
5545 /* The IDENTIFIER_CLASS_VALUEs are no longer valid. */
5551 }
5553 /* Get out of the current class scope. If we were in a class scope
5554 previously, that is the one popped to. */
5556 void
5558 {
5562 current_class_depth--;
5568 }
5570 /* Returns 1 if current_class_type is either T or a nested type of T.
5571 We start looking from 1 because entry 0 is from global scope, and has
5572 no type. */
5574 int
5576 {
5585 }
5587 /* If either current_class_type or one of its enclosing classes are derived
5588 from T, return the appropriate type. Used to determine how we found
5589 something via unqualified lookup. */
5591 tree
5593 {
5596 /* The bases of a dependent type are unknown. */
5608 }
5610 /* When entering a class scope, all enclosing class scopes' names with
5611 static meaning (static variables, static functions, types and
5612 enumerators) have to be visible. This recursive function calls
5613 pushclass for all enclosing class contexts until global or a local
5614 scope is reached. TYPE is the enclosed class. */
5616 void
5618 {
5619 tree context;
5621 /* A namespace might be passed in error cases, like A::B:C. */
5635 }
5637 /* Undoes a push_nested_class call. */
5639 void
5641 {
5647 }
5649 /* Returns the number of extern "LANG" blocks we are nested within. */
5651 int
5653 {
5655 }
5657 /* Set global variables CURRENT_LANG_NAME to appropriate value
5658 so that behavior of name-mangling machinery is correct. */
5660 void
5662 {
5666 {
5668 }
5670 {
5672 /* DECL_IGNORED_P is initially set for these types, to avoid clutter.
5673 (See record_builtin_java_type in decl.c.) However, that causes
5674 incorrect debug entries if these types are actually used.
5675 So we re-enable debug output after extern "Java". */
5684 }
5686 {
5688 }
5689 else
5691 }
5693 /* Get out of the current language scope. */
5695 void
5697 {
5700 }
5701 \f
5702 /* Type instantiation routines. */
5704 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
5705 matches the TARGET_TYPE. If there is no satisfactory match, return
5706 error_mark_node, and issue an error message if COMPLAIN is
5707 nonzero. Permit pointers to member function if PTRMEM is nonzero.
5708 If TEMPLATE_ONLY, the name of the overloaded function
5709 was a template-id, and EXPLICIT_TARGS are the explicitly provided
5710 template arguments. */
5712 static tree
5714 tree overload,
5718 tree explicit_targs)
5719 {
5720 /* Here's what the standard says:
5722 [over.over]
5724 If the name is a function template, template argument deduction
5725 is done, and if the argument deduction succeeds, the deduced
5726 arguments are used to generate a single template function, which
5727 is added to the set of overloaded functions considered.
5729 Non-member functions and static member functions match targets of
5730 type "pointer-to-function" or "reference-to-function." Nonstatic
5731 member functions match targets of type "pointer-to-member
5732 function;" the function type of the pointer to member is used to
5733 select the member function from the set of overloaded member
5734 functions. If a nonstatic member function is selected, the
5735 reference to the overloaded function name is required to have the
5736 form of a pointer to member as described in 5.3.1.
5738 If more than one function is selected, any template functions in
5739 the set are eliminated if the set also contains a non-template
5740 function, and any given template function is eliminated if the
5741 set contains a second template function that is more specialized
5742 than the first according to the partial ordering rules 14.5.5.2.
5743 After such eliminations, if any, there shall remain exactly one
5744 selected function. */
5748 /* We store the matches in a TREE_LIST rooted here. The functions
5749 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
5750 interoperability with most_specialized_instantiation. */
5752 tree fn;
5754 /* By the time we get here, we should be seeing only real
5755 pointer-to-member types, not the internal POINTER_TYPE to
5756 METHOD_TYPE representation. */
5764 /* Check that the TARGET_TYPE is reasonable. */
5768 /* This is OK, too. */
5771 {
5772 /* This is OK, too. This comes from a conversion to reference
5773 type. */
5776 }
5777 else
5778 {
5784 }
5786 /* If we can find a non-template function that matches, we can just
5787 use it. There's no point in generating template instantiations
5788 if we're just going to throw them out anyhow. But, of course, we
5789 can only do this when we don't *need* a template function. */
5791 {
5792 tree fns;
5795 {
5797 tree fntype;
5800 /* We're not looking for templates just yet. */
5805 /* We're looking for a non-static member, and this isn't
5806 one, or vice versa. */
5809 /* See if there's a match. */
5818 }
5819 }
5821 /* Now, if we've already got a match (or matches), there's no need
5822 to proceed to the template functions. But, if we don't have a
5823 match we need to look at them, too. */
5825 {
5826 tree target_fn_type;
5827 tree target_arg_types;
5828 tree target_ret_type;
5829 tree fns;
5832 target_fn_type
5834 else
5839 /* Never do unification on the 'this' parameter. */
5844 {
5846 tree instantiation;
5847 tree instantiation_type;
5848 tree targs;
5851 /* We're only looking for templates. */
5856 /* We're not looking for a non-static member, and this is
5857 one, or vice versa. */
5860 /* Try to do argument deduction. */
5865 /* Argument deduction failed. */
5868 /* Instantiate the template. */
5872 /* Instantiation failed. */
5875 /* See if there's a match. */
5878 instantiation_type =
5884 }
5886 /* Now, remove all but the most specialized of the matches. */
5888 {
5893 }
5894 }
5896 /* Now we should have exactly one function in MATCHES. */
5898 {
5899 /* There were *no* matches. */
5901 {
5904 target_type);
5906 /* print_candidates expects a chain with the functions in
5907 TREE_VALUE slots, so we cons one up here (we're losing anyway,
5908 so why be clever?). */
5911 matches);
5914 }
5916 }
5918 {
5919 /* There were too many matches. */
5922 {
5923 tree match;
5927 target_type);
5929 /* Since print_candidates expects the functions in the
5930 TREE_VALUE slot, we flip them here. */
5935 }
5938 }
5940 /* Good, exactly one match. Now, convert it to the correct type. */
5945 {
5953 {
5956 }
5957 }
5962 else
5963 {
5964 /* The target must be a REFERENCE_TYPE. Above, build_unary_op
5965 will mark the function as addressed, but here we must do it
5966 explicitly. */
5970 }
5971 }
5973 /* This function will instantiate the type of the expression given in
5974 RHS to match the type of LHSTYPE. If errors exist, then return
5975 error_mark_node. FLAGS is a bit mask. If ITF_COMPLAIN is set, then
5976 we complain on errors. If we are not complaining, never modify rhs,
5977 as overload resolution wants to try many possible instantiations, in
5978 the hope that at least one will work.
5980 For non-recursive calls, LHSTYPE should be a function, pointer to
5981 function, or a pointer to member function. */
5983 tree
5985 {
5992 {
5996 }
5999 {
6005 /* Microsoft allows `A::f' to be resolved to a
6006 pointer-to-member. */
6007 ;
6008 else
6009 {
6014 }
6015 }
6020 /* We don't overwrite rhs if it is an overloaded function.
6021 Copying it would destroy the tree link. */
6025 /* This should really only be used when attempting to distinguish
6026 what sort of a pointer to function we have. For now, any
6027 arithmetic operation which is not supported on pointers
6028 is rejected as an error. */
6031 {
6042 {
6043 tree new_rhs;
6053 }
6069 /* This can happen if we are forming a pointer-to-member for a
6070 member template. */
6073 /* Fall through. */
6076 {
6080 return
6082 fns,
6083 complain,
6084 allow_ptrmem,
6086 args);
6087 }
6091 return
6093 rhs,
6094 complain,
6095 allow_ptrmem,
6100 /* Now we should have a baselink. */
6106 /* This is too hard for now. */
6180 {
6184 }
6207 {
6212 }
6223 }
6224 }
6225 \f
6226 /* Return the name of the virtual function pointer field
6227 (as an IDENTIFIER_NODE) for the given TYPE. Note that
6228 this may have to look back through base types to find the
6229 ultimate field name. (For single inheritance, these could
6230 all be the same name. Who knows for multiple inheritance). */
6232 static tree
6234 {
6248 }
6250 void
6252 {
6253 #ifdef GATHER_STATISTICS
6259 {
6264 }
6265 #endif
6266 }
6268 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
6269 according to [class]:
6270 The class-name is also inserted
6271 into the scope of the class itself. For purposes of access checking,
6272 the inserted class name is treated as if it were a public member name. */
6274 void
6276 {
6279 tree saved_cas;
6293 }
6295 /* Returns 1 if TYPE contains only padding bytes. */
6297 int
6299 {
6306 /* In G++ 3.2, whether or not a class was empty was determined by
6307 looking at its size. */
6310 else
6312 }
6314 /* Returns true if TYPE contains an empty class. */
6316 static bool
6318 {
6322 {
6323 tree field;
6334 }
6338 }
6340 /* Find the enclosing class of the given NODE. NODE can be a *_DECL or
6341 a *_TYPE node. NODE can also be a local class. */
6343 tree
6345 {
6349 {
6351 {
6364 }
6365 }
6367 }
6369 /* Return 1 if TYPE or one of its enclosing classes is derived from BASE. */
6371 int
6373 {
6375 {
6380 }
6382 }
6384 /* Note that NAME was looked up while the current class was being
6385 defined and that the result of that lookup was DECL. */
6387 void
6389 {
6390 splay_tree names_used;
6392 /* If we're not defining a class, there's nothing to do. */
6396 /* If there's already a binding for this NAME, then we don't have
6397 anything to worry about. */
6409 }
6411 /* Note that NAME was declared (as DECL) in the current class. Check
6412 to see that the declaration is valid. */
6414 void
6416 {
6417 splay_tree names_used;
6418 splay_tree_node n;
6420 /* Look to see if we ever used this name. */
6421 names_used
6428 {
6429 /* [basic.scope.class]
6431 A name N used in a class S shall refer to the same declaration
6432 in its context and when re-evaluated in the completed scope of
6433 S. */
6438 }
6439 }
6441 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
6442 Secondary vtables are merged with primary vtables; this function
6443 will return the VAR_DECL for the primary vtable. */
6445 tree
6447 {
6448 tree decl;
6452 {
6456 }
6460 }
6463 /* Returns the binfo for the primary base of BINFO. If the resulting
6464 BINFO is a virtual base, and it is inherited elsewhere in the
6465 hierarchy, then the returned binfo might not be the primary base of
6466 BINFO in the complete object. Check BINFO_PRIMARY_P or
6467 BINFO_LOST_PRIMARY_P to be sure. */
6469 tree
6471 {
6472 tree primary_base;
6473 tree result;
6481 }
6483 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
6485 static int
6487 {
6491 }
6493 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
6494 INDENT should be zero when called from the top level; it is
6495 incremented recursively. IGO indicates the next expected BINFO in
6496 inheritance graph ordering. */
6498 static tree
6501 tree binfo,
6502 tree igo,
6504 {
6506 tree base_binfos;
6513 {
6516 }
6531 {
6535 TFF_PLAIN_IDENTIFIER),
6537 }
6539 {
6542 }
6547 {
6551 {
6555 TFF_PLAIN_IDENTIFIER));
6556 }
6558 {
6562 TFF_PLAIN_IDENTIFIER));
6563 }
6565 {
6569 TFF_PLAIN_IDENTIFIER));
6570 }
6572 {
6576 TFF_PLAIN_IDENTIFIER));
6577 }
6581 }
6585 {
6590 {
6595 }
6596 }
6599 }
6601 /* Dump the BINFO hierarchy for T. */
6603 static void
6605 {
6624 }
6626 static void
6628 {
6629 tree inits;
6631 HOST_WIDE_INT elt;
6639 TFF_PLAIN_IDENTIFIER));
6646 }
6648 static void
6650 {
6658 {
6665 {
6669 }
6673 }
6676 }
6678 static void
6680 {
6688 {
6693 }
6696 }
6698 /* Virtual function table initialization. */
6700 /* Create all the necessary vtables for T and its base classes. */
6702 static void
6704 {
6705 tree list;
6706 tree vbase;
6708 /* We lay out the primary and secondary vtables in one contiguous
6709 vtable. The primary vtable is first, followed by the non-virtual
6710 secondary vtables in inheritance graph order. */
6715 /* Then come the virtual bases, also in inheritance graph order. */
6717 {
6721 }
6725 }
6727 /* Initialize the vtable for BINFO with the INITS. */
6729 static void
6731 {
6732 tree decl;
6738 }
6740 /* Initialize DECL (a declaration for a namespace-scope array) with
6741 the INITS. */
6743 static void
6745 {
6746 tree context;
6754 }
6756 /* Build the VTT (virtual table table) for T.
6757 A class requires a VTT if it has virtual bases.
6759 This holds
6760 1 - primary virtual pointer for complete object T
6761 2 - secondary VTTs for each direct non-virtual base of T which requires a
6762 VTT
6763 3 - secondary virtual pointers for each direct or indirect base of T which
6764 has virtual bases or is reachable via a virtual path from T.
6765 4 - secondary VTTs for each direct or indirect virtual base of T.
6767 Secondary VTTs look like complete object VTTs without part 4. */
6769 static void
6771 {
6772 tree inits;
6773 tree type;
6774 tree vtt;
6775 tree index;
6777 /* Build up the initializers for the VTT. */
6782 /* If we didn't need a VTT, we're done. */
6786 /* Figure out the type of the VTT. */
6790 /* Now, build the VTT object itself. */
6793 /* Add the VTT to the vtables list. */
6798 }
6800 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
6801 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
6802 and CHAIN the vtable pointer for this binfo after construction is
6803 complete. VALUE can also be another BINFO, in which case we recurse. */
6805 static tree
6807 {
6808 tree vt;
6811 {
6817 else
6819 }
6822 }
6824 /* Recursively build the VTT-initializer for BINFO (which is in the
6825 hierarchy dominated by T). INITS points to the end of the initializer
6826 list to date. INDEX is the VTT index where the next element will be
6827 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
6828 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
6829 for virtual bases of T. When it is not so, we build the constructor
6830 vtables for the BINFO-in-T variant. */
6834 {
6836 tree b;
6837 tree init;
6838 tree secondary_vptrs;
6841 /* We only need VTTs for subobjects with virtual bases. */
6845 /* We need to use a construction vtable if this is not the primary
6846 VTT. */
6848 {
6851 /* Record the offset in the VTT where this sub-VTT can be found. */
6853 }
6855 /* Add the address of the primary vtable for the complete object. */
6860 {
6863 }
6866 /* Recursively add the secondary VTTs for non-virtual bases. */
6868 {
6873 }
6875 /* Add secondary virtual pointers for all subobjects of BINFO with
6876 either virtual bases or reachable along a virtual path, except
6877 subobjects that are non-virtual primary bases. */
6884 dfs_build_secondary_vptr_vtt_inits,
6885 NULL,
6886 dfs_ctor_vtable_bases_queue_p,
6887 secondary_vptrs);
6890 secondary_vptrs);
6894 /* The secondary vptrs come back in reverse order. After we reverse
6895 them, and add the INITS, the last init will be the first element
6896 of the chain. */
6899 {
6903 }
6905 /* Add the secondary VTTs for virtual bases. */
6908 {
6913 }
6916 {
6922 dfs_ctor_vtable_bases_queue_p,
6923 data);
6924 }
6927 }
6929 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo
6930 for the base in most derived. DATA is a TREE_LIST who's
6931 TREE_CHAIN is the type of the base being
6932 constructed whilst this secondary vptr is live. The TREE_UNSIGNED
6933 flag of DATA indicates that this is a constructor vtable. The
6934 TREE_TOP_LEVEL flag indicates that this is the primary VTT. */
6936 static tree
6938 {
6939 tree l;
6940 tree t;
6941 tree init;
6942 tree index;
6951 /* We don't care about bases that don't have vtables. */
6955 /* We're only interested in proper subobjects of T. */
6959 /* We're not interested in non-virtual primary bases. */
6963 /* If BINFO has virtual bases or is reachable via a virtual path
6964 from T, it'll have a secondary vptr. */
6969 /* Record the index where this secondary vptr can be found. */
6972 {
6975 }
6979 /* Add the initializer for the secondary vptr itself. */
6981 {
6982 /* It's a primary virtual base, and this is not the construction
6983 vtable. Find the base this is primary of in the inheritance graph,
6984 and use that base's vtable now. */
6987 }
6992 }
6994 /* dfs_walk_real predicate for building vtables. DATA is a TREE_LIST,
6995 VTT_MARKED_BINFO_P indicates whether marked or unmarked bases
6996 should be walked. TREE_PURPOSE is the TREE_TYPE that dominates the
6997 hierarchy. */
6999 static tree
7002 {
7008 }
7010 /* Called from build_vtt_inits via dfs_walk. After building constructor
7011 vtables and generating the sub-vtt from them, we need to restore the
7012 BINFO_VTABLES that were scribbled on. DATA is a TREE_LIST whose
7013 TREE_VALUE is the TREE_TYPE of the base whose sub vtt was generated. */
7015 static tree
7017 {
7020 /* We don't care about bases that don't have vtables. */
7024 /* If we scribbled the construction vtable vptr into BINFO, clear it
7025 out now. */
7033 }
7035 /* Build the construction vtable group for BINFO which is in the
7036 hierarchy dominated by T. */
7038 static void
7040 {
7041 tree list;
7042 tree type;
7043 tree vtbl;
7044 tree inits;
7045 tree id;
7046 tree vbase;
7048 /* See if we've already created this construction vtable group. */
7054 /* Build a version of VTBL (with the wrong type) for use in
7055 constructing the addresses of secondary vtables in the
7056 construction vtable group. */
7062 /* Add the vtables for each of our virtual bases using the vbase in T
7063 binfo. */
7065 vbase;
7067 {
7068 tree b;
7075 }
7078 /* Figure out the type of the construction vtable. */
7083 /* Initialize the construction vtable. */
7087 }
7089 /* Add the vtbl initializers for BINFO (and its bases other than
7090 non-virtual primaries) to the list of INITS. BINFO is in the
7091 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
7092 the constructor the vtbl inits should be accumulated for. (If this
7093 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
7094 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
7095 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
7096 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
7097 but are not necessarily the same in terms of layout. */
7099 static void
7101 tree orig_binfo,
7102 tree rtti_binfo,
7103 tree t,
7104 tree inits)
7105 {
7113 /* If it doesn't have a vptr, we don't do anything. */
7117 /* If we're building a construction vtable, we're not interested in
7118 subobjects that don't require construction vtables. */
7124 /* Build the initializers for the BINFO-in-T vtable. */
7130 /* Walk the BINFO and its bases. We walk in preorder so that as we
7131 initialize each vtable we can figure out at what offset the
7132 secondary vtable lies from the primary vtable. We can't use
7133 dfs_walk here because we need to iterate through bases of BINFO
7134 and RTTI_BINFO simultaneously. */
7136 {
7139 /* Skip virtual bases. */
7145 inits);
7146 }
7147 }
7149 /* Called from accumulate_vtbl_inits. Returns the initializers for
7150 the BINFO vtable. */
7152 static tree
7154 tree orig_binfo,
7155 tree rtti_binfo,
7156 tree t,
7157 tree l)
7158 {
7165 {
7166 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
7167 primary virtual base. If it is not the same primary in
7168 the hierarchy of T, we'll need to generate a ctor vtable
7169 for it, to place at its location in T. If it is the same
7170 primary, we still need a VTT entry for the vtable, but it
7171 should point to the ctor vtable for the base it is a
7172 primary for within the sub-hierarchy of RTTI_BINFO.
7174 There are three possible cases:
7176 1) We are in the same place.
7177 2) We are a primary base within a lost primary virtual base of
7178 RTTI_BINFO.
7179 3) We are primary to something not a base of RTTI_BINFO. */
7184 /* First, look through the bases we are primary to for RTTI_BINFO
7185 or a virtual base. */
7187 {
7191 }
7192 /* If we run out of primary links, keep looking down our
7193 inheritance chain; we might be an indirect primary. */
7199 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
7200 base B and it is a base of RTTI_BINFO, this is case 2. In
7201 either case, we share our vtable with LAST, i.e. the
7202 derived-most base within B of which we are a primary. */
7206 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
7207 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
7208 binfo_ctor_vtable after everything's been set up. */
7211 /* Otherwise, this is case 3 and we get our own. */
7212 }
7217 {
7218 tree index;
7221 /* Compute the initializer for this vtable. */
7225 /* Figure out the position to which the VPTR should point. */
7228 vtbl_ptr_type_node,
7229 vtbl);
7236 index);
7239 }
7242 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
7243 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
7244 straighten this out. */
7248 else
7249 /* For an ordinary vtable, set BINFO_VTABLE. */
7253 }
7255 /* Construct the initializer for BINFO's virtual function table. BINFO
7256 is part of the hierarchy dominated by T. If we're building a
7257 construction vtable, the ORIG_BINFO is the binfo we should use to
7258 find the actual function pointers to put in the vtable - but they
7259 can be overridden on the path to most-derived in the graph that
7260 ORIG_BINFO belongs. Otherwise,
7261 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
7262 BINFO that should be indicated by the RTTI information in the
7263 vtable; it will be a base class of T, rather than T itself, if we
7264 are building a construction vtable.
7266 The value returned is a TREE_LIST suitable for wrapping in a
7267 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
7268 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
7269 number of non-function entries in the vtable.
7271 It might seem that this function should never be called with a
7272 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
7273 base is always subsumed by a derived class vtable. However, when
7274 we are building construction vtables, we do build vtables for
7275 primary bases; we need these while the primary base is being
7276 constructed. */
7278 static tree
7280 tree orig_binfo,
7281 tree t,
7282 tree rtti_binfo,
7284 {
7286 tree vfun_inits;
7287 tree vbase;
7288 vtbl_init_data vid;
7290 /* Initialize VID. */
7299 /* The first vbase or vcall offset is at index -3 in the vtable. */
7302 /* Add entries to the vtable for RTTI. */
7305 /* Create an array for keeping track of the functions we've
7306 processed. When we see multiple functions with the same
7307 signature, we share the vcall offsets. */
7309 /* Add the vcall and vbase offset entries. */
7311 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
7312 build_vbase_offset_vtbl_entries. */
7314 vbase;
7318 /* If the target requires padding between data entries, add that now. */
7320 {
7324 {
7331 null_pointer_node),
7332 add);
7334 }
7335 }
7340 /* Go through all the ordinary virtual functions, building up
7341 initializers. */
7344 {
7345 tree delta;
7346 tree vcall_index;
7353 {
7357 }
7359 /* If the only definition of this function signature along our
7360 primary base chain is from a lost primary, this vtable slot will
7361 never be used, so just zero it out. This is important to avoid
7362 requiring extra thunks which cannot be generated with the function.
7364 We first check this in update_vtable_entry_for_fn, so we handle
7365 restored primary bases properly; we also need to do it here so we
7366 zero out unused slots in ctor vtables, rather than filling themff
7367 with erroneous values (though harmless, apart from relocation
7368 costs). */
7370 {
7371 /* We found a defn before a lost primary; go ahead as normal. */
7375 /* The nearest definition is from a lost primary; clear the
7376 slot. */
7378 {
7381 }
7382 }
7385 {
7386 /* Pull the offset for `this', and the function to call, out of
7387 the list. */
7394 /* You can't call an abstract virtual function; it's abstract.
7395 So, we replace these functions with __pure_virtual. */
7399 {
7403 }
7404 /* Take the address of the function, considering it to be of an
7405 appropriate generic type. */
7407 /* The address of a function can't change. */
7409 }
7411 /* And add it to the chain of initializers. */
7413 {
7418 else
7420 {
7427 }
7428 }
7429 else
7431 }
7433 /* The initializers for virtual functions were built up in reverse
7434 order; straighten them out now. */
7437 /* The negative offset initializers are also in reverse order. */
7440 /* Chain the two together. */
7442 }
7444 /* Adds to vid->inits the initializers for the vbase and vcall
7445 offsets in BINFO, which is in the hierarchy dominated by T. */
7447 static void
7449 {
7450 tree b;
7452 /* If this is a derived class, we must first create entries
7453 corresponding to the primary base class. */
7458 /* Add the vbase entries for this base. */
7460 /* Add the vcall entries for this base. */
7462 }
7464 /* Returns the initializers for the vbase offset entries in the vtable
7465 for BINFO (which is part of the class hierarchy dominated by T), in
7466 reverse order. VBASE_OFFSET_INDEX gives the vtable index
7467 where the next vbase offset will go. */
7469 static void
7471 {
7472 tree vbase;
7473 tree t;
7474 tree non_primary_binfo;
7476 /* If there are no virtual baseclasses, then there is nothing to
7477 do. */
7483 /* We might be a primary base class. Go up the inheritance hierarchy
7484 until we find the most derived class of which we are a primary base:
7485 it is the offset of that which we need to use. */
7488 {
7489 tree b;
7491 /* If we have reached a virtual base, then it must be a primary
7492 base (possibly multi-level) of vid->binfo, or we wouldn't
7493 have called build_vcall_and_vbase_vtbl_entries for it. But it
7494 might be a lost primary, so just skip down to vid->binfo. */
7496 {
7499 }
7505 }
7507 /* Go through the virtual bases, adding the offsets. */
7509 vbase;
7511 {
7512 tree b;
7513 tree delta;
7518 /* Find the instance of this virtual base in the complete
7519 object. */
7522 /* If we've already got an offset for this virtual base, we
7523 don't need another one. */
7528 /* Figure out where we can find this vbase offset. */
7537 {
7538 /* The vbase offset had better be the same. */
7542 }
7544 /* The next vbase will come at a more negative offset. */
7548 /* The initializer is the delta from BINFO to this virtual base.
7549 The vbase offsets go in reverse inheritance-graph order, and
7550 we are walking in inheritance graph order so these end up in
7551 the right order. */
7557 vtable_entry_type,
7558 delta)));
7560 }
7561 }
7563 /* Adds the initializers for the vcall offset entries in the vtable
7564 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
7565 to VID->INITS. */
7567 static void
7569 {
7570 /* We only need these entries if this base is a virtual base. We
7571 compute the indices -- but do not add to the vtable -- when
7572 building the main vtable for a class. */
7574 {
7575 /* We need a vcall offset for each of the virtual functions in this
7576 vtable. For example:
7578 class A { virtual void f (); };
7579 class B1 : virtual public A { virtual void f (); };
7580 class B2 : virtual public A { virtual void f (); };
7581 class C: public B1, public B2 { virtual void f (); };
7583 A C object has a primary base of B1, which has a primary base of A. A
7584 C also has a secondary base of B2, which no longer has a primary base
7585 of A. So the B2-in-C construction vtable needs a secondary vtable for
7586 A, which will adjust the A* to a B2* to call f. We have no way of
7587 knowing what (or even whether) this offset will be when we define B2,
7588 so we store this "vcall offset" in the A sub-vtable and look it up in
7589 a "virtual thunk" for B2::f.
7591 We need entries for all the functions in our primary vtable and
7592 in our non-virtual bases' secondary vtables. */
7594 /* If we are just computing the vcall indices -- but do not need
7595 the actual entries -- not that. */
7598 /* Now, walk through the non-virtual bases, adding vcall offsets. */
7600 }
7601 }
7603 /* Build vcall offsets, starting with those for BINFO. */
7605 static void
7607 {
7609 tree primary_binfo;
7611 /* Don't walk into virtual bases -- except, of course, for the
7612 virtual base for which we are building vcall offsets. Any
7613 primary virtual base will have already had its offsets generated
7614 through the recursion in build_vcall_and_vbase_vtbl_entries. */
7618 /* If BINFO has a primary base, process it first. */
7623 /* Add BINFO itself to the list. */
7626 /* Scan the non-primary bases of BINFO. */
7628 {
7629 tree base_binfo;
7634 }
7635 }
7637 /* Called from build_vcall_offset_vtbl_entries_r. */
7639 static void
7641 {
7642 /* Make entries for the rest of the virtuals. */
7644 {
7645 tree orig_fn;
7647 /* The ABI requires that the methods be processed in declaration
7648 order. G++ 3.2 used the order in the vtable. */
7650 orig_fn;
7654 }
7655 else
7656 {
7657 tree derived_virtuals;
7658 tree base_virtuals;
7659 tree orig_virtuals;
7660 /* If BINFO is a primary base, the most derived class which has
7661 BINFO as a primary base; otherwise, just BINFO. */
7662 tree non_primary_binfo;
7664 /* We might be a primary base class. Go up the inheritance hierarchy
7665 until we find the most derived class of which we are a primary base:
7666 it is the BINFO_VIRTUALS there that we need to consider. */
7669 {
7670 tree b;
7672 /* If we have reached a virtual base, then it must be vid->vbase,
7673 because we ignore other virtual bases in
7674 add_vcall_offset_vtbl_entries_r. In turn, it must be a primary
7675 base (possibly multi-level) of vid->binfo, or we wouldn't
7676 have called build_vcall_and_vbase_vtbl_entries for it. But it
7677 might be a lost primary, so just skip down to vid->binfo. */
7679 {
7684 }
7690 }
7693 /* For a ctor vtable we need the equivalent binfo within the hierarchy
7694 where rtti_binfo is the most derived type. */
7695 non_primary_binfo
7701 base_virtuals;
7705 {
7706 tree orig_fn;
7708 /* Find the declaration that originally caused this function to
7709 be present in BINFO_TYPE (binfo). */
7712 /* When processing BINFO, we only want to generate vcall slots for
7713 function slots introduced in BINFO. So don't try to generate
7714 one if the function isn't even defined in BINFO. */
7719 }
7720 }
7721 }
7723 /* Add a vcall offset entry for ORIG_FN to the vtable. */
7725 static void
7727 {
7729 tree vcall_offset;
7731 /* If there is already an entry for a function with the same
7732 signature as FN, then we do not need a second vcall offset.
7733 Check the list of functions already present in the derived
7734 class vtable. */
7736 {
7737 tree derived_entry;
7741 /* We only use one vcall offset for virtual destructors,
7742 even though there are two virtual table entries. */
7746 }
7748 /* If we are building these vcall offsets as part of building
7749 the vtable for the most derived class, remember the vcall
7750 offset. */
7756 /* The next vcall offset will be found at a more negative
7757 offset. */
7761 /* Keep track of this function. */
7765 {
7766 tree base;
7767 tree fn;
7769 /* Find the overriding function. */
7773 integer_zero_node);
7774 else
7775 {
7778 /* The vbase we're working on is a primary base of
7779 vid->binfo. But it might be a lost primary, so its
7780 BINFO_OFFSET might be wrong, so we just use the
7781 BINFO_OFFSET from vid->binfo. */
7785 vcall_offset));
7786 }
7787 /* Add the initializer to the vtable. */
7790 }
7791 }
7793 /* Return vtbl initializers for the RTTI entries corresponding to the
7794 BINFO's vtable. The RTTI entries should indicate the object given
7795 by VID->rtti_binfo. */
7797 static void
7799 {
7800 tree b;
7801 tree t;
7802 tree basetype;
7803 tree offset;
7804 tree decl;
7805 tree init;
7810 /* To find the complete object, we will first convert to our most
7811 primary base, and then add the offset in the vtbl to that value. */
7815 {
7816 tree primary_base;
7821 }
7824 /* The second entry is the address of the typeinfo object. */
7827 else
7830 /* Convert the declaration to a type that can be stored in the
7831 vtable. */
7836 /* Add the offset-to-top entry. It comes earlier in the vtable that
7837 the the typeinfo entry. Convert the offset to look like a
7838 function pointer, so that we can put it in the vtable. */
7842 }