| blob | 4d786a288c12da68d06f0f1b09e46b91d2c02a31 |
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, 2004, 2005, 2007, 2008
4 Free Software Foundation, Inc.
5 Contributed by Michael Tiemann (tiemann@cygnus.com)
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
12 any later version.
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
24 /* High-level class interface. */
41 /* The number of nested classes being processed. If we are not in the
42 scope of any class, this is zero. */
46 /* In order to deal with nested classes, we keep a stack of classes.
47 The topmost entry is the innermost class, and is the entry at index
48 CURRENT_CLASS_DEPTH */
51 /* The name of the class. */
52 tree name;
54 /* The _TYPE node for the class. */
55 tree type;
57 /* The access specifier pending for new declarations in the scope of
58 this class. */
59 tree access;
61 /* If were defining TYPE, the names used in this class. */
62 splay_tree names_used;
64 /* Nonzero if this class is no longer open, because of a call to
65 push_to_top_level. */
70 {
71 /* The base for which we're building initializers. */
72 tree binfo;
73 /* The type of the most-derived type. */
74 tree derived;
75 /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
76 unless ctor_vtbl_p is true. */
77 tree rtti_binfo;
78 /* The negative-index vtable initializers built up so far. These
79 are in order from least negative index to most negative index. */
80 tree inits;
81 /* The last (i.e., most negative) entry in INITS. */
83 /* The binfo for the virtual base for which we're building
84 vcall offset initializers. */
85 tree vbase;
86 /* The functions in vbase for which we have already provided vcall
87 offsets. */
89 /* The vtable index of the next vcall or vbase offset. */
90 tree index;
91 /* Nonzero if we are building the initializer for the primary
92 vtable. */
94 /* Nonzero if we are building the initializer for a construction
95 vtable. */
97 /* True when adding vcall offset entries to the vtable. False when
98 merely computing the indices. */
102 /* The type of a function passed to walk_subobject_offsets. */
105 /* The stack itself. This is a dynamically resized array. The
106 number of elements allocated is CURRENT_CLASS_STACK_SIZE. */
110 /* The size of the largest empty class seen in this translation unit. */
113 /* An array of all local classes present in this translation unit, in
114 declaration order. */
185 tree);
204 splay_tree_key k2);
213 /* Variables shared between class.c and call.c. */
215 #ifdef GATHER_STATISTICS
223 #endif
225 /* Convert to or from a base subobject. EXPR is an expression of type
226 `A' or `A*', an expression of type `B' or `B*' is returned. To
227 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
228 the B base instance within A. To convert base A to derived B, CODE
229 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
230 In this latter case, A must not be a morally virtual base of B.
231 NONNULL is true if EXPR is known to be non-NULL (this is only
232 needed when EXPR is of pointer type). CV qualifiers are preserved
233 from EXPR. */
235 tree
237 tree expr,
238 tree binfo,
240 {
243 tree probe;
244 tree offset;
245 tree target_type;
247 tree ptr_target_type;
257 {
263 }
275 /* Nothing to do. */
279 {
283 }
286 /* This must happen before the call to save_expr. */
293 /* Do we need to look in the vtable for the real offset? */
296 /* Don't bother with the calculations inside sizeof; they'll ICE if the
297 source type is incomplete and the pointer value doesn't matter. */
299 {
304 }
306 /* Do we need to check for a null pointer? */
308 {
309 /* If we know the conversion will not actually change the value
310 of EXPR, then we can avoid testing the expression for NULL.
311 We have to avoid generating a COMPONENT_REF for a base class
312 field, because other parts of the compiler know that such
313 expressions are always non-NULL. */
315 {
316 tree class_type;
317 /* TARGET_TYPE has been extracted from BINFO, and, is
318 therefore always cv-unqualified. Extract the
319 cv-qualifiers from EXPR so that the expression returned
320 matches the input. */
322 target_type
326 }
328 }
330 /* Protect against multiple evaluation if necessary. */
334 /* Now that we've saved expr, build the real null test. */
336 {
340 }
342 /* If this is a simple base reference, express it as a COMPONENT_REF. */
344 /* We don't build base fields for empty bases, and they aren't very
345 interesting to the optimizers anyway. */
347 {
354 }
357 {
358 /* Going via virtual base V_BINFO. We need the static offset
359 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
360 V_BINFO. That offset is an entry in D_BINFO's vtable. */
361 tree v_offset;
364 {
365 /* In a base member initializer, we cannot rely on the
366 vtable being set up. We have to indirect via the
367 vtt_parm. */
368 tree t;
374 tf_warning_or_error);
375 }
376 else
378 tf_warning_or_error),
385 v_offset);
397 /* Negative fixed_type_p means this is a constructor or destructor;
398 virtual base layout is fixed in in-charge [cd]tors, but not in
399 base [cd]tors. */
403 v_offset,
406 else
408 }
410 target_type = cp_build_qualified_type
419 {
424 }
425 else
431 out:
435 integer_zero_node));
438 }
440 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
441 Perform a derived-to-base conversion by recursively building up a
442 sequence of COMPONENT_REFs to the appropriate base fields. */
444 static tree
446 {
449 tree field;
452 {
453 tree temp;
457 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
458 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
459 an lvalue in the front end; only _DECLs and _REFs are lvalues
460 in the back end. */
466 }
468 /* Recurse. */
473 /* Is this the base field created by build_base_field? */
477 {
478 /* We don't use build_class_member_access_expr here, as that
479 has unnecessary checks, and more importantly results in
480 recursive calls to dfs_walk_once. */
488 /* Mark the expression const or volatile, as appropriate.
489 Even though we've dealt with the type above, we still have
490 to mark the expression itself. */
497 }
499 /* Didn't find the base field?!? */
501 }
503 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
504 type is a class type or a pointer to a class type. In the former
505 case, TYPE is also a class type; in the latter it is another
506 pointer type. If CHECK_ACCESS is true, an error message is emitted
507 if TYPE is inaccessible. If OBJECT has pointer type, the value is
508 assumed to be non-NULL. */
510 tree
512 {
513 tree binfo;
514 tree object_type;
517 {
520 }
521 else
526 NULL);
531 }
533 /* EXPR is an expression with unqualified class type. BASE is a base
534 binfo of that class type. Returns EXPR, converted to the BASE
535 type. This function assumes that EXPR is the most derived class;
536 therefore virtual bases can be found at their static offsets. */
538 tree
540 {
541 tree expr_type;
545 {
546 tree pointer_type;
550 /* We use fold_build2 and fold_convert below to simplify the trees
551 provided to the optimizers. It is not safe to call these functions
552 when processing a template because they do not handle C++-specific
553 trees. */
556 tf_warning_or_error);
562 }
565 }
567 \f
568 tree
570 {
576 /* First, convert to the requested type. */
581 /* Second, the requested type may not be the owner of its own vptr.
582 If not, convert to the base class that owns it. We cannot use
583 convert_to_base here, because VCONTEXT may appear more than once
584 in the inheritance hierarchy of TYPE, and thus direct conversion
585 between the types may be ambiguous. Following the path back up
586 one step at a time via primary bases avoids the problem. */
590 {
593 }
596 }
598 /* Given an object INSTANCE, return an expression which yields the
599 vtable element corresponding to INDEX. There are many special
600 cases for INSTANCE which we take care of here, mainly to avoid
601 creating extra tree nodes when we don't have to. */
603 static tree
605 {
606 tree aref;
609 /* Try to figure out what a reference refers to, and
610 access its virtual function table directly. */
618 {
623 }
634 }
636 tree
638 {
642 }
644 /* Given a stable object pointer INSTANCE_PTR, return an expression which
645 yields a function pointer corresponding to vtable element INDEX. */
647 tree
649 {
650 tree aref;
653 tf_warning_or_error),
654 idx);
656 /* When using function descriptors, the address of the
657 vtable entry is treated as a function pointer. */
661 tf_warning_or_error));
663 /* Remember this as a method reference, for later devirtualization. */
667 }
669 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
670 for the given TYPE. */
672 static tree
674 {
676 }
678 /* DECL is an entity associated with TYPE, like a virtual table or an
679 implicitly generated constructor. Determine whether or not DECL
680 should have external or internal linkage at the object file
681 level. This routine does not deal with COMDAT linkage and other
682 similar complexities; it simply sets TREE_PUBLIC if it possible for
683 entities in other translation units to contain copies of DECL, in
684 the abstract. */
686 void
688 {
689 /* If TYPE involves a local class in a function with internal
690 linkage, then DECL should have internal linkage too. Other local
691 classes have no linkage -- but if their containing functions
692 have external linkage, it makes sense for DECL to have external
693 linkage too. That will allow template definitions to be merged,
694 for example. */
696 {
699 }
700 else
702 }
704 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
705 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
706 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
708 static tree
710 {
711 tree decl;
714 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
715 now to avoid confusion in mangle_decl. */
724 /* At one time the vtable info was grabbed 2 words at a time. This
725 fails on sparc unless you have 8-byte alignment. (tiemann) */
729 /* The vtable has not been defined -- yet. */
733 /* Mark the VAR_DECL node representing the vtable itself as a
734 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
735 is rather important that such things be ignored because any
736 effort to actually generate DWARF for them will run into
737 trouble when/if we encounter code like:
739 #pragma interface
740 struct S { virtual void member (); };
742 because the artificial declaration of the vtable itself (as
743 manufactured by the g++ front end) will say that the vtable is
744 a static member of `S' but only *after* the debug output for
745 the definition of `S' has already been output. This causes
746 grief because the DWARF entry for the definition of the vtable
747 will try to refer back to an earlier *declaration* of the
748 vtable as a static member of `S' and there won't be one. We
749 might be able to arrange to have the "vtable static member"
750 attached to the member list for `S' before the debug info for
751 `S' get written (which would solve the problem) but that would
752 require more intrusive changes to the g++ front end. */
756 }
758 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
759 or even complete. If this does not exist, create it. If COMPLETE is
760 nonzero, then complete the definition of it -- that will render it
761 impossible to actually build the vtable, but is useful to get at those
762 which are known to exist in the runtime. */
764 tree
766 {
767 tree decl;
776 {
779 }
782 }
784 /* Build the primary virtual function table for TYPE. If BINFO is
785 non-NULL, build the vtable starting with the initial approximation
786 that it is the same as the one which is the head of the association
787 list. Returns a nonzero value if a new vtable is actually
788 created. */
790 static int
792 {
793 tree decl;
794 tree virtuals;
799 {
801 /* We have already created a vtable for this base, so there's
802 no need to do it again. */
809 }
810 else
811 {
814 }
816 #ifdef GATHER_STATISTICS
819 #endif
821 /* Initialize the association list for this type, based
822 on our first approximation. */
827 }
829 /* Give BINFO a new virtual function table which is initialized
830 with a skeleton-copy of its original initialization. The only
831 entry that changes is the `delta' entry, so we can really
832 share a lot of structure.
834 FOR_TYPE is the most derived type which caused this table to
835 be needed.
837 Returns nonzero if we haven't met BINFO before.
839 The order in which vtables are built (by calling this function) for
840 an object must remain the same, otherwise a binary incompatibility
841 can result. */
843 static int
845 {
847 /* We already created a vtable for this base. There's no need to
848 do it again. */
851 /* Remember that we've created a vtable for this BINFO, so that we
852 don't try to do so again. */
855 /* Make fresh virtual list, so we can smash it later. */
858 /* Secondary vtables are laid out as part of the same structure as
859 the primary vtable. */
862 }
864 /* Create a new vtable for BINFO which is the hierarchy dominated by
865 T. Return nonzero if we actually created a new vtable. */
867 static int
869 {
871 /* In this case, it is *type*'s vtable we are modifying. We start
872 with the approximation that its vtable is that of the
873 immediate base class. */
875 else
876 /* This is our very own copy of `basetype' to play with. Later,
877 we will fill in all the virtual functions that override the
878 virtual functions in these base classes which are not defined
879 by the current type. */
881 }
883 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
884 (which is in the hierarchy dominated by T) list FNDECL as its
885 BV_FN. DELTA is the required constant adjustment from the `this'
886 pointer where the vtable entry appears to the `this' required when
887 the function is actually called. */
889 static void
891 tree binfo,
892 tree fndecl,
893 tree delta,
895 {
896 tree v;
902 {
903 /* We need a new vtable for BINFO. */
905 {
906 /* If we really did make a new vtable, we also made a copy
907 of the BINFO_VIRTUALS list. Now, we have to find the
908 corresponding entry in that list. */
913 }
918 }
919 }
921 \f
922 /* Add method METHOD to class TYPE. If USING_DECL is non-null, it is
923 the USING_DECL naming METHOD. Returns true if the method could be
924 added to the method vec. */
926 bool
928 {
930 tree overload;
936 tree current_fns;
937 tree fns;
950 {
951 /* Make a new method vector. We start with 8 entries. We must
952 allocate at least two (for constructors and destructors), and
953 we're going to end up with an assignment operator at some
954 point as well. */
956 /* Create slots for constructors and destructors. */
960 }
962 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
965 /* Constructors and destructors go in special slots. */
969 {
973 {
979 type);
980 }
981 }
982 else
983 {
984 tree m;
987 /* See if we already have an entry with this name. */
991 {
994 {
999 }
1003 {
1006 }
1011 }
1012 }
1015 /* Check to see if we've already got this method. */
1017 {
1019 tree fn_type;
1020 tree method_type;
1021 tree parms1;
1022 tree parms2;
1027 /* [over.load] Member function declarations with the
1028 same name and the same parameter types cannot be
1029 overloaded if any of them is a static member
1030 function declaration.
1032 [namespace.udecl] When a using-declaration brings names
1033 from a base class into a derived class scope, member
1034 functions in the derived class override and/or hide member
1035 functions with the same name and parameter types in a base
1036 class (rather than conflicting). */
1042 /* Compare the quals on the 'this' parm. Don't compare
1043 the whole types, as used functions are treated as
1044 coming from the using class in overload resolution. */
1053 /* For templates, the return type and template parameters
1054 must be identical. */
1071 {
1073 {
1075 /* Defer to the local function. */
1079 else
1081 using_decl);
1082 }
1083 else
1084 {
1087 }
1089 /* We don't call duplicate_decls here to merge the
1090 declarations because that will confuse things if the
1091 methods have inline definitions. In particular, we
1092 will crash while processing the definitions. */
1094 }
1095 }
1097 /* A class should never have more than one destructor. */
1101 /* Add the new binding. */
1110 {
1113 /* We only expect to add few methods in the COMPLETE_P case, so
1114 just make room for one more method in that case. */
1117 else
1123 else
1125 }
1126 else
1127 /* Replace the current slot. */
1130 }
1132 /* Subroutines of finish_struct. */
1134 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1135 legit, otherwise return 0. */
1137 static int
1139 {
1140 tree elem;
1149 {
1151 {
1155 else
1158 }
1159 else
1160 {
1161 /* They're changing the access to the same thing they changed
1162 it to before. That's OK. */
1163 ;
1164 }
1165 }
1166 else
1167 {
1171 }
1173 }
1175 /* Process the USING_DECL, which is a member of T. */
1177 static void
1179 {
1182 tree access
1187 tree old_value;
1193 {
1199 else
1201 }
1209 ;
1211 {
1213 /* It's OK to use functions from a base when there are functions with
1215 else
1216 {
1221 }
1222 }
1224 {
1228 }
1230 /* Make type T see field decl FDECL with access ACCESS. */
1233 {
1236 }
1237 else
1239 }
1240 \f
1241 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1242 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1243 properties of the bases. */
1245 static void
1249 {
1252 tree base_binfo;
1253 tree binfo;
1259 {
1264 /* Effective C++ rule 14. We only need to check TYPE_POLYMORPHIC_P
1265 here because the case of virtual functions but non-virtual
1266 dtor is handled in finish_struct_1. */
1271 /* If the base class doesn't have copy constructors or
1272 assignment operators that take const references, then the
1273 derived class cannot have such a member automatically
1274 generated. */
1282 /* A virtual base does not effect nearly emptiness. */
1283 ;
1285 {
1287 /* And if there is more than one nearly empty base, then the
1288 derived class is not nearly empty either. */
1290 else
1291 /* Remember we've seen one. */
1293 }
1295 /* If the base class is not empty or nearly empty, then this
1296 class cannot be nearly empty. */
1299 /* A lot of properties from the bases also apply to the derived
1300 class. */
1311 }
1312 }
1314 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1315 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1316 that have had a nearly-empty virtual primary base stolen by some
1317 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1318 T. */
1320 static void
1322 {
1326 tree base_binfo;
1328 /* Determine the primary bases of our bases. */
1331 {
1334 /* See if we're the non-virtual primary of our inheritance
1335 chain. */
1337 {
1344 /* We are the primary binfo. */
1346 }
1347 /* Determine if we have a virtual primary base, and mark it so.
1348 */
1350 {
1354 /* Someone already claimed this base. */
1356 else
1357 {
1358 tree delta;
1363 /* A virtual binfo might have been copied from within
1364 another hierarchy. As we're about to use it as a
1365 primary base, make sure the offsets match. */
1372 }
1373 }
1374 }
1376 /* First look for a dynamic direct non-virtual base. */
1378 {
1382 {
1385 }
1386 }
1388 /* A "nearly-empty" virtual base class can be the primary base
1389 class, if no non-virtual polymorphic base can be found. Look for
1390 a nearly-empty virtual dynamic base that is not already a primary
1391 base of something in the hierarchy. If there is no such base,
1392 just pick the first nearly-empty virtual base. */
1398 {
1400 {
1401 /* Found one that is not primary. */
1404 }
1406 /* Remember the first candidate. */
1408 }
1410 found:
1411 /* If we've got a primary base, use it. */
1413 {
1418 /* We are stealing a primary base. */
1422 {
1423 tree delta;
1426 /* A virtual binfo might have been copied from within
1427 another hierarchy. As we're about to use it as a primary
1428 base, make sure the offsets match. */
1433 }
1440 }
1441 }
1442 \f
1443 /* Set memoizing fields and bits of T (and its variants) for later
1444 use. */
1446 static void
1448 {
1449 tree variants;
1451 /* Fix up variants (if any). */
1453 variants;
1455 {
1456 /* These fields are in the _TYPE part of the node, not in
1457 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1467 /* Copy whatever these are holding today. */
1472 /* All variants of a class have the same attributes. */
1474 }
1477 /* For a class w/o baseclasses, 'finish_struct' has set
1478 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
1479 Similarly for a class whose base classes do not have vtables.
1480 When neither of these is true, we might have removed abstract
1481 virtuals (by providing a definition), added some (by declaring
1482 new ones), or redeclared ones from a base class. We need to
1483 recalculate what's really an abstract virtual at this point (by
1484 looking in the vtables). */
1487 /* If this type has a copy constructor or a destructor, force its
1488 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
1489 nonzero. This will cause it to be passed by invisible reference
1490 and prevent it from being returned in a register. */
1492 {
1493 tree variants;
1496 {
1499 }
1500 }
1501 }
1503 /* Issue warnings about T having private constructors, but no friends,
1504 and so forth.
1506 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
1507 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
1508 non-private static member functions. */
1510 static void
1512 {
1515 tree fn;
1518 /* If the class has friends, those entities might create and
1519 access instances, so we should not warn. */
1522 /* We will have warned when the template was declared; there's
1523 no need to warn on every instantiation. */
1525 /* There's no reason to even consider warning about this
1526 class. */
1529 /* We only issue one warning, if more than one applies, because
1530 otherwise, on code like:
1532 class A {
1533 // Oops - forgot `public:'
1534 A();
1535 A(const A&);
1536 ~A();
1537 };
1539 we warn several times about essentially the same problem. */
1541 /* Check to see if all (non-constructor, non-destructor) member
1542 functions are private. (Since there are no friends or
1543 non-private statics, we can't ever call any of the private member
1544 functions.) */
1546 /* We're not interested in compiler-generated methods; they don't
1547 provide any way to call private members. */
1549 {
1551 {
1553 /* A non-private static member function is just like a
1554 friend; it can create and invoke private member
1555 functions, and be accessed without a class
1556 instance. */
1560 /* Keep searching for a static member function. */
1561 }
1564 }
1567 {
1568 /* There are no non-private methods, and there's at least one
1569 private member function that isn't a constructor or
1570 destructor. (If all the private members are
1571 constructors/destructors we want to use the code below that
1572 issues error messages specifically referring to
1573 constructors/destructors.) */
1579 {
1582 }
1584 {
1588 }
1589 }
1591 /* Even if some of the member functions are non-private, the class
1592 won't be useful for much if all the constructors or destructors
1593 are private: such an object can never be created or destroyed. */
1596 {
1599 t);
1601 }
1603 /* Warn about classes that have private constructors and no friends. */
1605 /* Implicitly generated constructors are always public. */
1608 {
1611 /* If a non-template class does not define a copy
1612 constructor, one is defined for it, enabling it to avoid
1613 this warning. For a template class, this does not
1614 happen, and so we would normally get a warning on:
1616 template <class T> class C { private: C(); };
1618 To avoid this asymmetry, we check TYPE_HAS_INIT_REF. All
1619 complete non-template or fully instantiated classes have this
1620 flag set. */
1623 else
1625 {
1627 /* Ideally, we wouldn't count copy constructors (or, in
1628 fact, any constructor that takes an argument of the
1629 class type as a parameter) because such things cannot
1630 be used to construct an instance of the class unless
1631 you already have one. But, for now at least, we're
1632 more generous. */
1634 {
1637 }
1638 }
1641 {
1644 t);
1646 }
1647 }
1648 }
1651 gt_pointer_operator new_value;
1655 /* Comparison function to compare two TYPE_METHOD_VEC entries by name. */
1657 static int
1659 {
1672 }
1674 /* This routine compares two fields like method_name_cmp but using the
1675 pointer operator in resort_field_decl_data. */
1677 static int
1679 {
1688 {
1695 }
1697 }
1699 /* Resort TYPE_METHOD_VEC because pointers have been reordered. */
1701 void
1704 gt_pointer_operator new_value,
1706 {
1710 tree fn;
1712 /* The type conversion ops have to live at the front of the vec, so we
1713 can't sort them. */
1721 {
1725 resort_method_name_cmp);
1726 }
1727 }
1729 /* Warn about duplicate methods in fn_fields.
1731 Sort methods that are not special (i.e., constructors, destructors,
1732 and type conversion operators) so that we can find them faster in
1733 search. */
1735 static void
1737 {
1738 tree fn_fields;
1748 /* Clear DECL_IN_AGGR_P for all functions. */
1753 /* Issue warnings about private constructors and such. If there are
1754 no methods, then some public defaults are generated. */
1757 /* The type conversion ops have to live at the front of the vec, so we
1758 can't sort them. */
1767 }
1769 /* Make BINFO's vtable have N entries, including RTTI entries,
1770 vbase and vcall offsets, etc. Set its type and call the back end
1771 to lay it out. */
1773 static void
1775 {
1776 tree atype;
1777 tree vtable;
1783 /* We may have to grow the vtable. */
1786 {
1790 }
1791 }
1793 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
1794 have the same signature. */
1796 int
1798 {
1799 /* One destructor overrides another if they are the same kind of
1800 destructor. */
1804 /* But a non-destructor never overrides a destructor, nor vice
1805 versa, nor do different kinds of destructors override
1806 one-another. For example, a complete object destructor does not
1807 override a deleting destructor. */
1816 {
1824 }
1826 }
1828 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
1829 subobject. */
1831 static bool
1833 {
1834 tree probe;
1837 {
1841 /* If we meet a virtual base, we can't follow the inheritance
1842 any more. See if the complete type of DERIVED contains
1843 such a virtual base. */
1846 }
1848 }
1851 /* The function for which we are trying to find a final overrider. */
1852 tree fn;
1853 /* The base class in which the function was declared. */
1854 tree declaring_base;
1855 /* The candidate overriders. */
1856 tree candidates;
1857 /* Path to most derived. */
1861 /* Add the overrider along the current path to FFOD->CANDIDATES.
1862 Returns true if an overrider was found; false otherwise. */
1864 static bool
1868 {
1869 tree method;
1871 /* If BINFO is not the most derived type, try a more derived class.
1872 A definition there will overrider a definition here. */
1874 {
1875 depth--;
1879 }
1883 {
1886 /* Remove any candidates overridden by this new function. */
1888 {
1889 /* If *CANDIDATE overrides METHOD, then METHOD
1890 cannot override anything else on the list. */
1893 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
1896 else
1898 }
1900 /* Add the new function. */
1903 }
1906 }
1908 /* Called from find_final_overrider via dfs_walk. */
1910 static tree
1912 {
1920 }
1922 static tree
1924 {
1929 }
1931 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
1932 FN and whose TREE_VALUE is the binfo for the base where the
1933 overriding occurs. BINFO (in the hierarchy dominated by the binfo
1934 DERIVED) is the base object in which FN is declared. */
1936 static tree
1938 {
1939 find_final_overrider_data ffod;
1941 /* Getting this right is a little tricky. This is valid:
1943 struct S { virtual void f (); };
1944 struct T { virtual void f (); };
1945 struct U : public S, public T { };
1947 even though calling `f' in `U' is ambiguous. But,
1949 struct R { virtual void f(); };
1950 struct S : virtual public R { virtual void f (); };
1951 struct T : virtual public R { virtual void f (); };
1952 struct U : public S, public T { };
1954 is not -- there's no way to decide whether to put `S::f' or
1955 `T::f' in the vtable for `R'.
1957 The solution is to look at all paths to BINFO. If we find
1958 different overriders along any two, then there is a problem. */
1962 /* Determine the depth of the hierarchy. */
1973 /* If there was no winner, issue an error message. */
1978 }
1980 /* Return the index of the vcall offset for FN when TYPE is used as a
1981 virtual base. */
1983 static tree
1985 {
1987 tree_pair_p p;
1995 /* There should always be an appropriate index. */
1997 }
1999 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2000 dominated by T. FN has been overridden in BINFO; VIRTUALS points to the
2001 corresponding position in the BINFO_VIRTUALS list. */
2003 static void
2006 {
2007 tree b;
2008 tree overrider;
2009 tree delta;
2010 tree virtual_base;
2011 tree first_defn;
2017 /* Find the nearest primary base (possibly binfo itself) which defines
2018 this function; this is the class the caller will convert to when
2019 calling FN through BINFO. */
2021 {
2026 /* The nearest definition is from a lost primary. */
2029 }
2032 /* Find the final overrider. */
2035 {
2038 }
2041 /* Check for adjusting covariant return types. */
2049 /* If the overrider is invalid, don't even try. */
2051 {
2052 /* If FN is a covariant thunk, we must figure out the adjustment
2053 to the final base FN was converting to. As OVERRIDER_TARGET might
2054 also be converting to the return type of FN, we have to
2055 combine the two conversions here. */
2062 {
2066 }
2067 else
2071 /* Find the equivalent binfo within the return type of the
2072 overriding function. We will want the vbase offset from
2073 there. */
2075 over_return);
2078 {
2079 /* There was no existing virtual thunk (which takes
2080 precedence). So find the binfo of the base function's
2081 return type within the overriding function's return type.
2082 We cannot call lookup base here, because we're inside a
2083 dfs_walk, and will therefore clobber the BINFO_MARKED
2084 flags. Fortunately we know the covariancy is valid (it
2085 has already been checked), so we can just iterate along
2086 the binfos, which have been chained in inheritance graph
2087 order. Of course it is lame that we have to repeat the
2088 search here anyway -- we should really be caching pieces
2089 of the vtable and avoiding this repeated work. */
2092 /* Find the base binfo within the overriding function's
2093 return type. We will always find a thunk_binfo, except
2094 when the covariancy is invalid (which we will have
2095 already diagnosed). */
2098 thunk_binfo;
2104 /* See if virtual inheritance is involved. */
2106 virtual_offset;
2113 {
2117 {
2118 /* We convert via virtual base. Adjust the fixed
2119 offset to be from there. */
2120 offset = size_diffop
2123 }
2125 /* There was an existing fixed offset, this must be
2126 from the base just converted to, and the base the
2127 FN was thunking to. */
2129 else
2131 }
2132 }
2135 /* Replace the overriding function with a covariant thunk. We
2136 will emit the overriding function in its own slot as
2137 well. */
2140 }
2141 else
2145 /* Assume that we will produce a thunk that convert all the way to
2146 the final overrider, and not to an intermediate virtual base. */
2149 /* See if we can convert to an intermediate virtual base first, and then
2150 use the vcall offset located there to finish the conversion. */
2152 {
2153 /* If we find the final overrider, then we can stop
2154 walking. */
2159 /* If we find a virtual base, and we haven't yet found the
2160 overrider, then there is a virtual base between the
2161 declaring base (first_defn) and the final overrider. */
2163 {
2166 }
2167 }
2170 {
2171 /* The ABI specifies that a covariant thunk includes a mangling
2172 for a this pointer adjustment. This-adjusting thunks that
2173 override a function from a virtual base have a vcall
2174 adjustment. When the virtual base in question is a primary
2175 virtual base, we know the adjustments are zero, (and in the
2176 non-covariant case, we would not use the thunk).
2177 Unfortunately we didn't notice this could happen, when
2178 designing the ABI and so never mandated that such a covariant
2179 thunk should be emitted. Because we must use the ABI mandated
2180 name, we must continue searching from the binfo where we
2181 found the most recent definition of the function, towards the
2182 primary binfo which first introduced the function into the
2183 vtable. If that enters a virtual base, we must use a vcall
2184 this-adjusting thunk. Bleah! */
2193 /* Even if we find a virtual base, the correct delta is
2194 between the overrider and the binfo we're building a vtable
2195 for. */
2197 }
2199 /* Compute the constant adjustment to the `this' pointer. The
2200 `this' pointer, when this function is called, will point at BINFO
2201 (or one of its primary bases, which are at the same offset). */
2203 /* The `this' pointer needs to be adjusted from the declaration to
2204 the nearest virtual base. */
2208 /* If the nearest definition is in a lost primary, we don't need an
2209 entry in our vtable. Except possibly in a constructor vtable,
2210 if we happen to get our primary back. In that case, the offset
2211 will be zero, as it will be a primary base. */
2213 else
2214 /* The `this' pointer needs to be adjusted from pointing to
2215 BINFO to pointing at the base where the final overrider
2216 appears. */
2217 virtual_covariant:
2227 else
2229 }
2231 /* Called from modify_all_vtables via dfs_walk. */
2233 static tree
2235 {
2237 tree virtuals;
2238 tree old_virtuals;
2242 /* A base without a vtable needs no modification, and its bases
2243 are uninteresting. */
2248 /* Don't do the primary vtable, if it's new. */
2252 /* There's no need to modify the vtable for a non-virtual primary
2253 base; we're not going to use that vtable anyhow. We do still
2254 need to do this for virtual primary bases, as they could become
2255 non-primary in a construction vtable. */
2260 /* Now, go through each of the virtual functions in the virtual
2261 function table for BINFO. Find the final overrider, and update
2262 the BINFO_VIRTUALS list appropriately. */
2265 virtuals;
2269 binfo,
2274 }
2276 /* Update all of the primary and secondary vtables for T. Create new
2277 vtables as required, and initialize their RTTI information. Each
2278 of the functions in VIRTUALS is declared in T and may override a
2279 virtual function from a base class; find and modify the appropriate
2280 entries to point to the overriding functions. Returns a list, in
2281 declaration order, of the virtual functions that are declared in T,
2282 but do not appear in the primary base class vtable, and which
2283 should therefore be appended to the end of the vtable for T. */
2285 static tree
2287 {
2291 /* Update all of the vtables. */
2294 /* Add virtual functions not already in our primary vtable. These
2295 will be both those introduced by this class, and those overridden
2296 from secondary bases. It does not include virtuals merely
2297 inherited from secondary bases. */
2299 {
2304 {
2305 /* We don't need to adjust the `this' pointer when
2306 calling this function. */
2310 /* This is a function not already in our vtable. Keep it. */
2312 }
2313 else
2314 /* We've already got an entry for this function. Skip it. */
2316 }
2319 }
2321 /* Get the base virtual function declarations in T that have the
2322 indicated NAME. */
2324 static tree
2326 {
2327 tree methods;
2332 /* Find virtual functions in T with the indicated NAME. */
2336 methods;
2338 {
2344 }
2350 {
2353 base_fndecls);
2354 }
2357 }
2359 /* If this declaration supersedes the declaration of
2360 a method declared virtual in the base class, then
2361 mark this field as being virtual as well. */
2363 void
2365 {
2367 /* In [temp.mem] we have:
2369 A specialization of a member function template does not
2370 override a virtual function from a base class. */
2377 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2378 the error_mark_node so that we know it is an overriding
2379 function. */
2383 {
2387 }
2388 }
2390 /* Warn about hidden virtual functions that are not overridden in t.
2391 We know that constructors and destructors don't apply. */
2393 static void
2395 {
2397 tree fns;
2400 /* We go through each separately named virtual function. */
2404 {
2405 tree fn;
2406 tree name;
2407 tree fndecl;
2408 tree base_fndecls;
2409 tree base_binfo;
2410 tree binfo;
2413 /* All functions in this slot in the CLASSTYPE_METHOD_VEC will
2414 have the same name. Figure out what name that is. */
2416 /* There are no possibly hidden functions yet. */
2418 /* Iterate through all of the base classes looking for possibly
2419 hidden functions. */
2422 {
2425 base_fndecls);
2426 }
2428 /* If there are no functions to hide, continue. */
2432 /* Remove any overridden functions. */
2434 {
2437 {
2441 /* If the method from the base class has the same
2442 signature as the method from the derived class, it
2443 has been overridden. */
2446 else
2448 }
2449 }
2451 /* Now give a warning for all base functions without overriders,
2452 as they are hidden. */
2454 {
2455 /* Here we know it is a hider, and no overrider exists. */
2459 }
2460 }
2461 }
2463 /* Check for things that are invalid. There are probably plenty of other
2464 things we should check for also. */
2466 static void
2468 {
2469 tree field;
2472 {
2480 {
2484 {
2485 /* We're generally only interested in entities the user
2486 declared, but we also find nested classes by noticing
2487 the TYPE_DECL that we create implicitly. You're
2488 allowed to put one anonymous union inside another,
2489 though, so we explicitly tolerate that. We use
2490 TYPE_ANONYMOUS_P rather than ANON_AGGR_TYPE_P so that
2491 we also allow unnamed types used for defining fields. */
2498 {
2502 else
2506 }
2509 {
2512 else
2514 }
2516 {
2519 else
2521 }
2525 }
2526 }
2527 }
2528 }
2530 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2531 will be used later during class template instantiation.
2532 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2533 a non-static member data (FIELD_DECL), a member function
2534 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2535 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2536 When FRIEND_P is nonzero, T is either a friend class
2537 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2538 (FUNCTION_DECL, TEMPLATE_DECL). */
2540 void
2542 {
2543 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2548 }
2550 /* Create default constructors, assignment operators, and so forth for
2551 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
2552 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
2553 the class cannot have a default constructor, copy constructor
2554 taking a const reference argument, or an assignment operator taking
2555 a const reference, respectively. */
2557 static void
2561 {
2562 /* Destructor. */
2564 {
2565 /* In general, we create destructors lazily. */
2567 /* However, if the implicit destructor is non-trivial
2568 destructor, we sometimes have to create it at this point. */
2570 {
2574 /* If this a Java class, any non-trivial destructor is
2575 invalid, even if compiler-generated. Therefore, if the
2576 destructor is non-trivial we create it now. */
2578 else
2579 {
2580 tree binfo;
2581 tree base_binfo;
2584 /* If the implicit destructor will be virtual, then we must
2585 generate it now because (unfortunately) we do not
2586 generate virtual tables lazily. */
2589 {
2590 tree base_type;
2591 tree dtor;
2596 {
2599 }
2600 }
2601 }
2603 /* If we can't get away with being lazy, generate the destructor
2604 now. */
2607 }
2608 }
2610 /* [class.ctor]
2612 If there is no user-declared constructor for a class, a default
2613 constructor is implicitly declared. */
2615 {
2618 }
2620 /* [class.ctor]
2622 If a class definition does not explicitly declare a copy
2623 constructor, one is declared implicitly. */
2625 {
2629 }
2631 /* If there is no assignment operator, one will be created if and
2632 when it is needed. For now, just record whether or not the type
2633 of the parameter to the assignment operator will be a const or
2634 non-const reference. */
2636 {
2640 }
2641 }
2643 /* Subroutine of finish_struct_1. Recursively count the number of fields
2644 in TYPE, including anonymous union members. */
2646 static int
2648 {
2649 tree x;
2652 {
2655 else
2657 }
2659 }
2661 /* Subroutine of finish_struct_1. Recursively add all the fields in the
2662 TREE_LIST FIELDS to the SORTED_FIELDS_TYPE elts, starting at offset IDX. */
2664 static int
2666 {
2667 tree x;
2669 {
2672 else
2674 }
2676 }
2678 /* FIELD is a bit-field. We are finishing the processing for its
2679 enclosing type. Issue any appropriate messages and set appropriate
2680 flags. Returns false if an error has been diagnosed. */
2682 static bool
2684 {
2686 tree w;
2688 /* Extract the declared width of the bitfield, which has been
2689 temporarily stashed in DECL_INITIAL. */
2692 /* Remove the bit-field width indicator so that the rest of the
2693 compiler does not treat that value as an initializer. */
2696 /* Detect invalid bit-field type. */
2698 {
2701 }
2702 else
2703 {
2704 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
2707 /* detect invalid field size. */
2711 {
2714 }
2716 {
2719 }
2721 {
2724 }
2734 min_precision
2738 }
2741 {
2745 }
2746 else
2747 {
2748 /* Non-bit-fields are aligned for their type. */
2752 }
2753 }
2755 /* FIELD is a non bit-field. We are finishing the processing for its
2756 enclosing type T. Issue any appropriate messages and set appropriate
2757 flags. */
2759 static void
2761 tree t,
2765 {
2768 /* An anonymous union cannot contain any fields which would change
2769 the settings of CANT_HAVE_CONST_CTOR and friends. */
2771 ;
2772 /* And, we don't set TYPE_HAS_CONST_INIT_REF, etc., for anonymous
2773 structs. So, we recurse through their fields here. */
2775 {
2776 tree fields;
2782 }
2783 /* Check members with class type for constructors, destructors,
2784 etc. */
2786 {
2787 /* Never let anything with uninheritable virtuals
2788 make it through without complaint. */
2792 {
2795 field);
2800 field);
2801 }
2802 else
2803 {
2810 }
2817 }
2819 {
2820 /* `build_class_init_list' does not recognize
2821 non-FIELD_DECLs. */
2825 }
2826 }
2828 /* Check the data members (both static and non-static), class-scoped
2829 typedefs, etc., appearing in the declaration of T. Issue
2830 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
2831 declaration order) of access declarations; each TREE_VALUE in this
2832 list is a USING_DECL.
2834 In addition, set the following flags:
2836 EMPTY_P
2837 The class is empty, i.e., contains no non-static data members.
2839 CANT_HAVE_CONST_CTOR_P
2840 This class cannot have an implicitly generated copy constructor
2841 taking a const reference.
2843 CANT_HAVE_CONST_ASN_REF
2844 This class cannot have an implicitly generated assignment
2845 operator taking a const reference.
2847 All of these flags should be initialized before calling this
2848 function.
2850 Returns a pointer to the end of the TYPE_FIELDs chain; additional
2851 fields can be added by adding to this chain. */
2853 static void
2857 {
2864 /* Assume there are no access declarations. */
2866 /* Assume this class has no pointer members. */
2868 /* Assume none of the members of this class have default
2869 initializations. */
2873 {
2880 {
2881 /* Prune the access declaration from the list of fields. */
2884 /* Save the access declarations for our caller. */
2887 /* Since we've reset *FIELD there's no reason to skip to the
2888 next field. */
2891 }
2897 /* If we've gotten this far, it's a data member, possibly static,
2898 or an enumerator. */
2901 /* When this goes into scope, it will be a non-local reference. */
2905 {
2906 /* [class.union]
2908 If a union contains a static data member, or a member of
2909 reference type, the program is ill-formed. */
2911 {
2914 }
2916 {
2921 }
2922 }
2924 /* Perform error checking that did not get done in
2925 grokdeclarator. */
2927 {
2931 }
2933 {
2937 }
2945 /* Now it can only be a FIELD_DECL. */
2950 /* If this is of reference type, check if it needs an init. */
2952 {
2957 /* ARM $12.6.2: [A member initializer list] (or, for an
2958 aggregate, initialization by a brace-enclosed list) is the
2959 only way to initialize nonstatic const and reference
2960 members. */
2962 }
2967 {
2969 {
2970 warning
2973 x);
2975 }
2978 }
2981 /* We don't treat zero-width bitfields as making a class
2982 non-empty. */
2983 ;
2984 else
2985 {
2986 /* The class is non-empty. */
2988 /* The class is not even nearly empty. */
2990 /* If one of the data members contains an empty class,
2991 so does T. */
2995 }
2997 /* This is used by -Weffc++ (see below). Warn only for pointers
2998 to members which might hold dynamic memory. So do not warn
2999 for pointers to functions or pointers to members. */
3006 {
3011 }
3017 /* DR 148 now allows pointers to members (which are POD themselves),
3018 to be allowed in POD structs. */
3024 /* If any field is const, the structure type is pseudo-const. */
3026 {
3031 /* ARM $12.6.2: [A member initializer list] (or, for an
3032 aggregate, initialization by a brace-enclosed list) is the
3033 only way to initialize nonstatic const and reference
3034 members. */
3036 }
3037 /* A field that is pseudo-const makes the structure likewise. */
3039 {
3044 }
3046 /* Core issue 80: A nonstatic data member is required to have a
3047 different name from the class iff the class has a
3048 user-defined constructor. */
3053 /* We set DECL_C_BIT_FIELD in grokbitfield.
3054 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3057 cant_have_const_ctor_p,
3058 no_const_asn_ref_p,
3060 }
3062 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3063 it should also define a copy constructor and an assignment operator to
3064 implement the correct copy semantic (deep vs shallow, etc.). As it is
3065 not feasible to check whether the constructors do allocate dynamic memory
3066 and store it within members, we approximate the warning like this:
3068 -- Warn only if there are members which are pointers
3069 -- Warn only if there is a non-trivial constructor (otherwise,
3070 there cannot be memory allocated).
3071 -- Warn only if there is a non-trivial destructor. We assume that the
3072 user at least implemented the cleanup correctly, and a destructor
3073 is needed to free dynamic memory.
3075 This seems enough for practical purposes. */
3077 && has_pointers
3081 {
3085 {
3090 }
3094 }
3096 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3100 /* Check anonymous struct/anonymous union fields. */
3103 /* We've built up the list of access declarations in reverse order.
3104 Fix that now. */
3106 }
3108 /* If TYPE is an empty class type, records its OFFSET in the table of
3109 OFFSETS. */
3111 static int
3113 {
3114 splay_tree_node n;
3119 /* Record the location of this empty object in OFFSETS. */
3127 type,
3131 }
3133 /* Returns nonzero if TYPE is an empty class type and there is
3134 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3136 static int
3138 {
3139 splay_tree_node n;
3140 tree t;
3145 /* Record the location of this empty object in OFFSETS. */
3155 }
3157 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3158 F for every subobject, passing it the type, offset, and table of
3159 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3160 be traversed.
3162 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3163 than MAX_OFFSET will not be walked.
3165 If F returns a nonzero value, the traversal ceases, and that value
3166 is returned. Otherwise, returns zero. */
3168 static int
3170 subobject_offset_fn f,
3171 tree offset,
3172 splay_tree offsets,
3173 tree max_offset,
3175 {
3179 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3180 stop. */
3188 {
3192 }
3195 {
3196 tree field;
3197 tree binfo;
3200 /* Avoid recursing into objects that are not interesting. */
3204 /* Record the location of TYPE. */
3209 /* Iterate through the direct base classes of TYPE. */
3213 {
3214 tree binfo_offset;
3227 offset,
3229 else
3230 {
3231 tree orig_binfo;
3232 /* We cannot rely on BINFO_OFFSET being set for the base
3233 class yet, but the offsets for direct non-virtual
3234 bases can be calculated by going back to the TYPE. */
3237 offset,
3239 }
3242 f,
3243 binfo_offset,
3244 offsets,
3245 max_offset,
3250 }
3253 {
3257 /* Iterate through the virtual base classes of TYPE. In G++
3258 3.2, we included virtual bases in the direct base class
3259 loop above, which results in incorrect results; the
3260 correct offsets for virtual bases are only known when
3261 working with the most derived type. */
3265 {
3267 f,
3269 offset,
3271 offsets,
3272 max_offset,
3276 }
3277 else
3278 {
3279 /* We still have to walk the primary base, if it is
3280 virtual. (If it is non-virtual, then it was walked
3281 above.) */
3287 {
3288 r = (walk_subobject_offsets
3293 }
3294 }
3295 }
3297 /* Iterate through the fields of TYPE. */
3300 {
3301 tree field_offset;
3305 else
3306 /* In G++ 3.2, DECL_FIELD_OFFSET was used. */
3310 f,
3312 offset,
3313 field_offset),
3314 offsets,
3315 max_offset,
3319 }
3320 }
3322 {
3325 tree index;
3327 /* Avoid recursing into objects that are not interesting. */
3332 /* Step through each of the elements in the array. */
3334 /* G++ 3.2 had an off-by-one error here. */
3339 {
3341 f,
3342 offset,
3343 offsets,
3344 max_offset,
3350 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3351 there's no point in iterating through the remaining
3352 elements of the array. */
3355 }
3356 }
3359 }
3361 /* Record all of the empty subobjects of TYPE (either a type or a
3362 binfo). If IS_DATA_MEMBER is true, then a non-static data member
3363 is being placed at OFFSET; otherwise, it is a base class that is
3364 being placed at OFFSET. */
3366 static void
3368 tree offset,
3369 splay_tree offsets,
3371 {
3372 tree max_offset;
3373 /* If recording subobjects for a non-static data member or a
3374 non-empty base class , we do not need to record offsets beyond
3375 the size of the biggest empty class. Additional data members
3376 will go at the end of the class. Additional base classes will go
3377 either at offset zero (if empty, in which case they cannot
3378 overlap with offsets past the size of the biggest empty class) or
3379 at the end of the class.
3381 However, if we are placing an empty base class, then we must record
3382 all offsets, as either the empty class is at offset zero (where
3383 other empty classes might later be placed) or at the end of the
3384 class (where other objects might then be placed, so other empty
3385 subobjects might later overlap). */
3389 else
3393 }
3395 /* Returns nonzero if any of the empty subobjects of TYPE (located at
3396 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
3397 virtual bases of TYPE are examined. */
3399 static int
3401 tree offset,
3402 splay_tree offsets,
3404 {
3405 splay_tree_node max_node;
3407 /* Get the node in OFFSETS that indicates the maximum offset where
3408 an empty subobject is located. */
3410 /* If there aren't any empty subobjects, then there's no point in
3411 performing this check. */
3417 vbases_p);
3418 }
3420 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
3421 non-static data member of the type indicated by RLI. BINFO is the
3422 binfo corresponding to the base subobject, OFFSETS maps offsets to
3423 types already located at those offsets. This function determines
3424 the position of the DECL. */
3426 static void
3428 tree decl,
3429 tree binfo,
3430 splay_tree offsets)
3431 {
3434 tree type;
3437 {
3438 /* For the purposes of determining layout conflicts, we want to
3439 use the class type of BINFO; TREE_TYPE (DECL) will be the
3440 CLASSTYPE_AS_BASE version, which does not contain entries for
3441 zero-sized bases. */
3444 }
3445 else
3446 {
3449 }
3451 /* Try to place the field. It may take more than one try if we have
3452 a hard time placing the field without putting two objects of the
3453 same type at the same address. */
3455 {
3458 /* Place this field. */
3462 /* We have to check to see whether or not there is already
3463 something of the same type at the offset we're about to use.
3464 For example, consider:
3466 struct S {};
3467 struct T : public S { int i; };
3468 struct U : public S, public T {};
3470 Here, we put S at offset zero in U. Then, we can't put T at
3471 offset zero -- its S component would be at the same address
3472 as the S we already allocated. So, we have to skip ahead.
3473 Since all data members, including those whose type is an
3474 empty class, have nonzero size, any overlap can happen only
3475 with a direct or indirect base-class -- it can't happen with
3476 a data member. */
3477 /* In a union, overlap is permitted; all members are placed at
3478 offset zero. */
3481 /* G++ 3.2 did not check for overlaps when placing a non-empty
3482 virtual base. */
3487 {
3488 /* Strip off the size allocated to this field. That puts us
3489 at the first place we could have put the field with
3490 proper alignment. */
3493 /* Bump up by the alignment required for the type. */
3494 rli->bitpos
3500 }
3501 else
3502 /* There was no conflict. We're done laying out this field. */
3504 }
3506 /* Now that we know where it will be placed, update its
3507 BINFO_OFFSET. */
3509 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
3510 this point because their BINFO_OFFSET is copied from another
3511 hierarchy. Therefore, we may not need to add the entire
3512 OFFSET. */
3517 }
3519 /* Returns true if TYPE is empty and OFFSET is nonzero. */
3521 static int
3523 tree offset,
3524 splay_tree offsets ATTRIBUTE_UNUSED)
3525 {
3527 }
3529 /* Layout the empty base BINFO. EOC indicates the byte currently just
3530 past the end of the class, and should be correctly aligned for a
3531 class of the type indicated by BINFO; OFFSETS gives the offsets of
3532 the empty bases allocated so far. T is the most derived
3533 type. Return nonzero iff we added it at the end. */
3535 static bool
3538 {
3539 tree alignment;
3543 /* This routine should only be used for empty classes. */
3548 {
3550 propagate_binfo_offsets
3552 else
3554 "offset of empty base %qT may not be ABI-compliant and may"
3557 }
3559 /* This is an empty base class. We first try to put it at offset
3560 zero. */
3563 offsets,
3565 {
3566 /* That didn't work. Now, we move forward from the next
3567 available spot in the class. */
3571 {
3574 offsets,
3576 /* We finally found a spot where there's no overlap. */
3579 /* There's overlap here, too. Bump along to the next spot. */
3581 }
3582 }
3585 {
3590 }
3593 }
3595 /* Layout the base given by BINFO in the class indicated by RLI.
3596 *BASE_ALIGN is a running maximum of the alignments of
3597 any base class. OFFSETS gives the location of empty base
3598 subobjects. T is the most derived type. Return nonzero if the new
3599 object cannot be nearly-empty. A new FIELD_DECL is inserted at
3600 *NEXT_FIELD, unless BINFO is for an empty base class.
3602 Returns the location at which the next field should be inserted. */
3607 {
3612 /* This error is now reported in xref_tag, thus giving better
3613 location information. */
3616 /* Place the base class. */
3618 {
3619 tree decl;
3621 /* The containing class is non-empty because it has a non-empty
3622 base class. */
3625 /* Create the FIELD_DECL. */
3631 {
3639 /* Try to place the field. It may take more than one try if we
3640 have a hard time placing the field without putting two
3641 objects of the same type at the same address. */
3643 /* Add the new FIELD_DECL to the list of fields for T. */
3647 }
3648 }
3649 else
3650 {
3651 tree eoc;
3654 /* On some platforms (ARM), even empty classes will not be
3655 byte-aligned. */
3659 /* A nearly-empty class "has no proper base class that is empty,
3660 not morally virtual, and at an offset other than zero." */
3662 {
3665 /* The check above (used in G++ 3.2) is insufficient because
3666 an empty class placed at offset zero might itself have an
3667 empty base at a nonzero offset. */
3669 empty_base_at_nonzero_offset_p,
3670 size_zero_node,
3674 {
3677 else
3679 "class %qT will be considered nearly empty in a "
3681 }
3682 }
3684 /* We do not create a FIELD_DECL for empty base classes because
3685 it might overlap some other field. We want to be able to
3686 create CONSTRUCTORs for the class by iterating over the
3687 FIELD_DECLs, and the back end does not handle overlapping
3688 FIELD_DECLs. */
3690 /* An empty virtual base causes a class to be non-empty
3691 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
3692 here because that was already done when the virtual table
3693 pointer was created. */
3694 }
3696 /* Record the offsets of BINFO and its base subobjects. */
3699 offsets,
3703 }
3705 /* Layout all of the non-virtual base classes. Record empty
3706 subobjects in OFFSETS. T is the most derived type. Return nonzero
3707 if the type cannot be nearly empty. The fields created
3708 corresponding to the base classes will be inserted at
3709 *NEXT_FIELD. */
3711 static void
3714 {
3715 /* Chain to hold all the new FIELD_DECLs which stand in for base class
3716 subobjects. */
3721 /* The primary base class is always allocated first. */
3726 /* Now allocate the rest of the bases. */
3728 {
3729 tree base_binfo;
3733 /* The primary base was already allocated above, so we don't
3734 need to allocate it again here. */
3738 /* Virtual bases are added at the end (a primary virtual base
3739 will have already been added). */
3745 }
3746 }
3748 /* Go through the TYPE_METHODS of T issuing any appropriate
3749 diagnostics, figuring out which methods override which other
3750 methods, and so forth. */
3752 static void
3754 {
3755 tree x;
3758 {
3762 /* The name of the field is the original field name
3763 Save this in auxiliary field for later overloading. */
3765 {
3769 }
3770 /* All user-declared destructors are non-trivial. */
3773 }
3774 }
3776 /* FN is a constructor or destructor. Clone the declaration to create
3777 a specialized in-charge or not-in-charge version, as indicated by
3778 NAME. */
3780 static tree
3782 {
3783 tree parms;
3784 tree clone;
3786 /* Copy the function. */
3788 /* Remember where this function came from. */
3791 /* Reset the function name. */
3794 /* There's no pending inline data for this function. */
3797 /* And it hasn't yet been deferred. */
3800 /* The base-class destructor is not virtual. */
3802 {
3806 }
3808 /* If there was an in-charge parameter, drop it from the function
3809 type. */
3811 {
3812 tree basetype;
3813 tree parmtypes;
3814 tree exceptions;
3819 /* Skip the `this' parameter. */
3821 /* Skip the in-charge parameter. */
3823 /* And the VTT parm, in a complete [cd]tor. */
3827 /* If this is subobject constructor or destructor, add the vtt
3828 parameter. */
3832 parmtypes);
3835 exceptions);
3839 }
3841 /* Copy the function parameters. But, DECL_ARGUMENTS on a TEMPLATE_DECL
3842 aren't function parameters; those are the template parameters. */
3844 {
3846 /* Remove the in-charge parameter. */
3848 {
3852 }
3853 /* And the VTT parm, in a complete [cd]tor. */
3855 {
3858 else
3859 {
3863 }
3864 }
3867 {
3870 }
3871 }
3873 /* Create the RTL for this function. */
3877 /* Make it easy to find the CLONE given the FN. */
3881 /* If this is a template, handle the DECL_TEMPLATE_RESULT as well. */
3883 {
3884 tree result;
3891 }
3896 }
3898 /* Produce declarations for all appropriate clones of FN. If
3899 UPDATE_METHOD_VEC_P is nonzero, the clones are added to the
3900 CLASTYPE_METHOD_VEC as well. */
3902 void
3904 {
3905 tree clone;
3907 /* Avoid inappropriate cloning. */
3913 {
3914 /* For each constructor, we need two variants: an in-charge version
3915 and a not-in-charge version. */
3922 }
3923 else
3924 {
3927 /* For each destructor, we need three variants: an in-charge
3928 version, a not-in-charge version, and an in-charge deleting
3929 version. We clone the deleting version first because that
3930 means it will go second on the TYPE_METHODS list -- and that
3931 corresponds to the correct layout order in the virtual
3932 function table.
3934 For a non-virtual destructor, we do not build a deleting
3935 destructor. */
3937 {
3941 }
3948 }
3950 /* Note that this is an abstract function that is never emitted. */
3952 }
3954 /* DECL is an in charge constructor, which is being defined. This will
3955 have had an in class declaration, from whence clones were
3956 declared. An out-of-class definition can specify additional default
3957 arguments. As it is the clones that are involved in overload
3958 resolution, we must propagate the information from the DECL to its
3959 clones. */
3961 void
3963 {
3964 tree clone;
3968 {
3975 /* Skip the 'this' parameter. */
3991 {
3996 {
3997 /* A default parameter has been added. Adjust the
3998 clone's parameters. */
4001 tree type;
4006 {
4009 clone_parms);
4011 }
4014 clone_parms);
4021 }
4022 }
4024 }
4025 }
4027 /* For each of the constructors and destructors in T, create an
4028 in-charge and not-in-charge variant. */
4030 static void
4032 {
4033 tree fns;
4035 /* If for some reason we don't have a CLASSTYPE_METHOD_VEC, we bail
4036 out now. */
4044 }
4046 /* Returns true iff class T has a user-defined constructor other than
4047 the default constructor. */
4049 bool
4051 {
4052 tree fns;
4058 {
4065 }
4068 }
4070 /* Remove all zero-width bit-fields from T. */
4072 static void
4074 {
4079 {
4084 else
4086 }
4087 }
4089 /* Returns TRUE iff we need a cookie when dynamically allocating an
4090 array whose elements have the indicated class TYPE. */
4092 static bool
4094 {
4095 tree fns;
4100 /* If there's a non-trivial destructor, we need a cookie. In order
4101 to iterate through the array calling the destructor for each
4102 element, we'll have to know how many elements there are. */
4106 /* If the usual deallocation function is a two-argument whose second
4107 argument is of type `size_t', then we have to pass the size of
4108 the array to the deallocation function, so we will need to store
4109 a cookie. */
4113 /* If there are no `operator []' members, or the lookup is
4114 ambiguous, then we don't need a cookie. */
4117 /* Loop through all of the functions. */
4119 {
4120 tree fn;
4121 tree second_parm;
4123 /* Select the current function. */
4125 /* See if this function is a one-argument delete function. If
4126 it is, then it will be the usual deallocation function. */
4130 /* Otherwise, if we have a two-argument function and the second
4131 argument is `size_t', it will be the usual deallocation
4132 function -- unless there is one-argument function, too. */
4136 }
4139 }
4141 /* Check the validity of the bases and members declared in T. Add any
4142 implicitly-generated functions (like copy-constructors and
4143 assignment operators). Compute various flag bits (like
4144 CLASSTYPE_NON_POD_T) for T. This routine works purely at the C++
4145 level: i.e., independently of the ABI in use. */
4147 static void
4149 {
4150 /* Nonzero if the implicitly generated copy constructor should take
4151 a non-const reference argument. */
4153 /* Nonzero if the implicitly generated assignment operator
4154 should take a non-const reference argument. */
4156 tree access_decls;
4158 /* By default, we use const reference arguments and generate default
4159 constructors. */
4163 /* Check all the base-classes. */
4167 /* Check all the method declarations. */
4170 /* Check all the data member declarations. We cannot call
4171 check_field_decls until we have called check_bases check_methods,
4172 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
4173 being set appropriately. */
4178 /* A nearly-empty class has to be vptr-containing; a nearly empty
4179 class contains just a vptr. */
4183 /* Do some bookkeeping that will guide the generation of implicitly
4184 declared member functions. */
4187 /* We need to call a constructor for this class if it has a
4188 user-declared constructor, or if the default constructor is going
4189 to initialize the vptr. (This is not an if-and-only-if;
4190 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
4191 themselves need constructing.) */
4194 /* [dcl.init.aggr]
4196 An aggregate is an arry or a class with no user-declared
4197 constructors ... and no virtual functions.
4199 Again, other conditions for being an aggregate are checked
4200 elsewhere. */
4212 /* If the class has no user-declared constructor, but does have
4213 non-static const or reference data members that can never be
4214 initialized, issue a warning. */
4216 /* Classes with user-declared constructors are presumed to
4217 initialize these members. */
4219 /* Aggregates can be initialized with brace-enclosed
4220 initializers. */
4222 {
4223 tree field;
4226 {
4227 tree type;
4241 }
4242 }
4244 /* Synthesize any needed methods. */
4246 cant_have_const_ctor,
4247 no_const_asn_ref);
4249 /* Create the in-charge and not-in-charge variants of constructors
4250 and destructors. */
4253 /* Process the using-declarations. */
4257 /* Build and sort the CLASSTYPE_METHOD_VEC. */
4260 /* Figure out whether or not we will need a cookie when dynamically
4261 allocating an array of this type. */
4264 }
4266 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
4267 accordingly. If a new vfield was created (because T doesn't have a
4268 primary base class), then the newly created field is returned. It
4269 is not added to the TYPE_FIELDS list; it is the caller's
4270 responsibility to do that. Accumulate declared virtual functions
4271 on VIRTUALS_P. */
4273 static tree
4275 {
4276 tree fn;
4278 /* Collect the virtual functions declared in T. */
4282 {
4291 }
4293 /* If we couldn't find an appropriate base class, create a new field
4294 here. Even if there weren't any new virtual functions, we might need a
4295 new virtual function table if we're supposed to include vptrs in
4296 all classes that need them. */
4298 {
4299 /* We build this decl with vtbl_ptr_type_node, which is a
4300 `vtable_entry_type*'. It might seem more precise to use
4301 `vtable_entry_type (*)[N]' where N is the number of virtual
4302 functions. However, that would require the vtable pointer in
4303 base classes to have a different type than the vtable pointer
4304 in derived classes. We could make that happen, but that
4305 still wouldn't solve all the problems. In particular, the
4306 type-based alias analysis code would decide that assignments
4307 to the base class vtable pointer can't alias assignments to
4308 the derived class vtable pointer, since they have different
4309 types. Thus, in a derived class destructor, where the base
4310 class constructor was inlined, we could generate bad code for
4311 setting up the vtable pointer.
4313 Therefore, we use one type for all vtable pointers. We still
4314 use a type-correct type; it's just doesn't indicate the array
4315 bounds. That's better than using `void*' or some such; it's
4316 cleaner, and it let's the alias analysis code know that these
4317 stores cannot alias stores to void*! */
4318 tree field;
4328 /* This class is non-empty. */
4332 }
4335 }
4337 /* Fixup the inline function given by INFO now that the class is
4338 complete. */
4340 static void
4342 {
4344 {
4347 {
4350 }
4351 }
4352 }
4354 /* Fixup the inline methods and friends in TYPE now that TYPE is
4355 complete. */
4357 static void
4359 {
4365 {
4370 else
4372 }
4374 /* Do inline member functions. */
4378 /* Do friends. */
4383 }
4385 /* Add OFFSET to all base types of BINFO which is a base in the
4386 hierarchy dominated by T.
4388 OFFSET, which is a type offset, is number of bytes. */
4390 static void
4392 {
4394 tree primary_binfo;
4395 tree base_binfo;
4397 /* Update BINFO's offset. */
4402 offset));
4404 /* Find the primary base class. */
4410 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
4411 downwards. */
4413 {
4414 /* Don't do the primary base twice. */
4422 }
4423 }
4425 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
4426 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
4427 empty subobjects of T. */
4429 static void
4431 {
4432 tree vbase;
4441 {
4442 /* In G++ 3.2, we incorrectly rounded the size before laying out
4443 the virtual bases. */
4445 #ifdef STRUCTURE_SIZE_BOUNDARY
4446 /* Packed structures don't need to have minimum size. */
4449 #endif
4453 }
4455 /* Find the last field. The artificial fields created for virtual
4456 bases will go after the last extant field to date. */
4461 /* Go through the virtual bases, allocating space for each virtual
4462 base that is not already a primary base class. These are
4463 allocated in inheritance graph order. */
4465 {
4470 {
4473 /* This virtual base is not a primary base of any class in the
4474 hierarchy, so we have to add space for it. */
4478 /* If the first virtual base might have been placed at a
4479 lower address, had we started from CLASSTYPE_SIZE, rather
4480 than TYPE_SIZE, issue a warning. There can be both false
4481 positives and false negatives from this warning in rare
4482 cases; to deal with all the possibilities would probably
4483 require performing both layout algorithms and comparing
4484 the results which is not particularly tractable. */
4486 && first_vbase
4487 && (tree_int_cst_lt
4491 bitsize_unit_node),
4494 "offset of virtual base %qT is not ABI-compliant and "
4496 basetype);
4499 }
4500 }
4501 }
4503 /* Returns the offset of the byte just past the end of the base class
4504 BINFO. */
4506 static tree
4508 {
4509 tree size;
4514 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
4515 allocate some space for it. It cannot have virtual bases, so
4516 TYPE_SIZE_UNIT is fine. */
4518 else
4522 }
4524 /* Returns the offset of the byte just past the end of the base class
4525 with the highest offset in T. If INCLUDE_VIRTUALS_P is zero, then
4526 only non-virtual bases are included. */
4528 static tree
4530 {
4533 tree binfo;
4534 tree base_binfo;
4535 tree offset;
4540 {
4550 }
4552 /* G++ 3.2 did not check indirect virtual bases. */
4556 {
4560 }
4563 }
4565 /* Warn about bases of T that are inaccessible because they are
4566 ambiguous. For example:
4568 struct S {};
4569 struct T : public S {};
4570 struct U : public S, public T {};
4572 Here, `(S*) new U' is not allowed because there are two `S'
4573 subobjects of U. */
4575 static void
4577 {
4580 tree basetype;
4581 tree binfo;
4582 tree base_binfo;
4584 /* If there are no repeated bases, nothing can be ambiguous. */
4588 /* Check direct bases. */
4591 {
4597 }
4599 /* Check for ambiguous virtual bases. */
4603 {
4609 }
4610 }
4612 /* Compare two INTEGER_CSTs K1 and K2. */
4614 static int
4616 {
4618 }
4620 /* Increase the size indicated in RLI to account for empty classes
4621 that are "off the end" of the class. */
4623 static void
4625 {
4626 tree eoc;
4627 tree rli_size;
4629 /* It might be the case that we grew the class to allocate a
4630 zero-sized base class. That won't be reflected in RLI, yet,
4631 because we are willing to overlay multiple bases at the same
4632 offset. However, now we need to make sure that RLI is big enough
4633 to reflect the entire class. */
4639 {
4641 /* In version 1 of the ABI, the size of a class that ends with
4642 a bitfield was not rounded up to a whole multiple of a
4643 byte. Because rli_size_unit_so_far returns only the number
4644 of fully allocated bytes, any extra bits were not included
4645 in the size. */
4647 else
4648 /* The size should have been rounded to a whole byte. */
4651 rli->bitpos
4660 }
4661 }
4663 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
4664 BINFO_OFFSETs for all of the base-classes. Position the vtable
4665 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
4667 static void
4669 {
4670 tree non_static_data_members;
4671 tree field;
4672 tree vptr;
4673 record_layout_info rli;
4674 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
4675 types that appear at that offset. */
4676 splay_tree empty_base_offsets;
4677 /* True if the last field layed out was a bit-field. */
4679 /* The location at which the next field should be inserted. */
4681 /* T, as a base class. */
4682 tree base_t;
4684 /* Keep track of the first non-static data member. */
4687 /* Start laying out the record. */
4690 /* Mark all the primary bases in the hierarchy. */
4693 /* Create a pointer to our virtual function table. */
4696 /* The vptr is always the first thing in the class. */
4698 {
4703 }
4704 else
4707 /* Build FIELD_DECLs for all of the non-virtual base-types. */
4712 /* Layout the non-static data members. */
4714 {
4715 tree type;
4716 tree padding;
4718 /* We still pass things that aren't non-static data members to
4719 the back end, in case it wants to do something with them. */
4721 {
4723 /* If the static data member has incomplete type, keep track
4724 of it so that it can be completed later. (The handling
4725 of pending statics in finish_record_layout is
4726 insufficient; consider:
4728 struct S1;
4729 struct S2 { static S1 s1; };
4731 At this point, finish_record_layout will be called, but
4732 S1 is still incomplete.) */
4734 {
4736 /* The visibility of static data members is determined
4737 at their point of declaration, not their point of
4738 definition. */
4740 }
4742 }
4750 /* If this field is a bit-field whose width is greater than its
4751 type, then there are some special rules for allocating
4752 it. */
4755 {
4756 integer_type_kind itk;
4757 tree integer_type;
4759 /* We must allocate the bits as if suitably aligned for the
4760 longest integer type that fits in this many bits. type
4761 of the field. Then, we are supposed to use the left over
4762 bits as additional padding. */
4768 /* ITK now indicates a type that is too large for the
4769 field. We have to back up by one to find the largest
4770 type that fits. */
4773 /* Figure out how much additional padding is required. GCC
4774 3.2 always created a padding field, even if it had zero
4775 width. */
4778 {
4780 /* In a union, the padding field must have the full width
4781 of the bit-field; all fields start at offset zero. */
4783 else
4784 {
4787 "ABI-compliant and may change in a future "
4789 t);
4792 }
4793 }
4794 #ifdef PCC_BITFIELD_TYPE_MATTERS
4795 /* An unnamed bitfield does not normally affect the
4796 alignment of the containing class on a target where
4797 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
4798 make any exceptions for unnamed bitfields when the
4799 bitfields are longer than their types. Therefore, we
4800 temporarily give the field a name. */
4802 {
4805 }
4806 #endif
4811 empty_base_offsets);
4814 /* Now that layout has been performed, set the size of the
4815 field to the size of its declared type; the rest of the
4816 field is effectively invisible. */
4818 /* We must also reset the DECL_MODE of the field. */
4823 /* Versions of G++ before G++ 3.4 did not reset the
4824 DECL_MODE. */
4826 "the offset of %qD may not be ABI-compliant and may "
4828 }
4829 else
4831 empty_base_offsets);
4833 /* Remember the location of any empty classes in FIELD. */
4837 empty_base_offsets,
4840 /* If a bit-field does not immediately follow another bit-field,
4841 and yet it starts in the middle of a byte, we have failed to
4842 comply with the ABI. */
4845 /* The TREE_NO_WARNING flag gets set by Objective-C when
4846 laying out an Objective-C class. The ObjC ABI differs
4847 from the C++ ABI, and so we do not want a warning
4848 here. */
4850 && !last_field_was_bitfield
4853 bitsize_unit_node)))
4857 /* G++ used to use DECL_FIELD_OFFSET as if it were the byte
4858 offset of the field. */
4864 "classes to be placed at different locations in a "
4867 /* The middle end uses the type of expressions to determine the
4868 possible range of expression values. In order to optimize
4869 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
4870 must be made aware of the width of "i", via its type.
4872 Because C++ does not have integer types of arbitrary width,
4873 we must (for the purposes of the front end) convert from the
4874 type assigned here to the declared type of the bitfield
4875 whenever a bitfield expression is used as an rvalue.
4876 Similarly, when assigning a value to a bitfield, the value
4877 must be converted to the type given the bitfield here. */
4879 {
4884 {
4891 }
4892 }
4894 /* If we needed additional padding after this field, add it
4895 now. */
4897 {
4898 tree padding_field;
4901 NULL_TREE,
4902 char_type_node);
4909 NULL_TREE,
4910 empty_base_offsets);
4911 }
4914 }
4917 {
4918 /* Make sure that we are on a byte boundary so that the size of
4919 the class without virtual bases will always be a round number
4920 of bytes. */
4923 }
4925 /* G++ 3.2 does not allow virtual bases to be overlaid with tail
4926 padding. */
4930 /* Delete all zero-width bit-fields from the list of fields. Now
4931 that the type is laid out they are no longer important. */
4934 /* Create the version of T used for virtual bases. We do not use
4935 make_class_type for this version; this is an artificial type. For
4936 a POD type, we just reuse T. */
4938 {
4941 /* Set the size and alignment for the new type. In G++ 3.2, all
4942 empty classes were considered to have size zero when used as
4943 base classes. */
4945 {
4950 "layout of classes derived from empty class %qT "
4952 t);
4953 }
4954 else
4955 {
4956 tree eoc;
4958 /* If the ABI version is not at least two, and the last
4959 field was a bit-field, RLI may not be on a byte
4960 boundary. In particular, rli_size_unit_so_far might
4961 indicate the last complete byte, while rli_size_so_far
4962 indicates the total number of bits used. Therefore,
4963 rli_size_so_far, rather than rli_size_unit_so_far, is
4964 used to compute TYPE_SIZE_UNIT. */
4972 eoc);
4979 }
4983 /* Copy the fields from T. */
4987 {
4998 }
5000 /* Record the base version of the type. */
5003 }
5004 else
5007 /* Every empty class contains an empty class. */
5011 /* Set the TYPE_DECL for this type to contain the right
5012 value for DECL_OFFSET, so that we can use it as part
5013 of a COMPONENT_REF for multiple inheritance. */
5016 /* Now fix up any virtual base class types that we left lying
5017 around. We must get these done before we try to lay out the
5018 virtual function table. As a side-effect, this will remove the
5019 base subobject fields. */
5022 /* Make sure that empty classes are reflected in RLI at this
5023 point. */
5026 /* Make sure not to create any structures with zero size. */
5031 /* Let the back end lay out the type. */
5034 /* Warn about bases that can't be talked about due to ambiguity. */
5037 /* Now that we're done with layout, give the base fields the real types. */
5042 /* Clean up. */
5049 }
5051 /* Determine the "key method" for the class type indicated by TYPE,
5052 and set CLASSTYPE_KEY_METHOD accordingly. */
5054 void
5056 {
5057 tree method;
5060 || processing_template_decl
5065 /* The key method is the first non-pure virtual function that is not
5066 inline at the point of class definition. On some targets the
5067 key function may not be inline; those targets should not call
5068 this function until the end of the translation unit. */
5074 {
5077 }
5080 }
5082 /* Perform processing required when the definition of T (a class type)
5083 is complete. */
5085 void
5087 {
5088 tree x;
5089 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
5094 {
5099 }
5101 /* If this type was previously laid out as a forward reference,
5102 make sure we lay it out again. */
5108 /* Make assumptions about the class; we'll reset the flags if
5109 necessary. */
5114 /* Do end-of-class semantic processing: checking the validity of the
5115 bases and members and add implicitly generated methods. */
5118 /* Find the key method. */
5120 {
5121 /* The Itanium C++ ABI permits the key method to be chosen when
5122 the class is defined -- even though the key method so
5123 selected may later turn out to be an inline function. On
5124 some systems (such as ARM Symbian OS) the key method cannot
5125 be determined until the end of the translation unit. On such
5126 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
5127 will cause the class to be added to KEYED_CLASSES. Then, in
5128 finish_file we will determine the key method. */
5132 /* If a polymorphic class has no key method, we may emit the vtable
5133 in every translation unit where the class definition appears. */
5136 }
5138 /* Layout the class itself. */
5141 /* We use the base type for trivial assignments, and hence it
5142 needs a mode. */
5147 /* If necessary, create the primary vtable for this class. */
5149 {
5150 /* We must enter these virtuals into the table. */
5154 /* Here we know enough to change the type of our virtual
5155 function table, but we will wait until later this function. */
5157 }
5160 {
5162 tree fn;
5169 /* Add entries for virtual functions introduced by this class. */
5173 /* Set DECL_VINDEX for all functions declared in this class. */
5175 fn;
5177 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
5179 {
5183 /* A thunk. We should never be calling this entry directly
5184 from this vtable -- we'd use the entry for the non
5185 thunk base function. */
5189 }
5190 }
5194 /* Complete the rtl for any static member objects of the type we're
5195 working on. */
5202 /* Done with FIELDS...now decide whether to sort these for
5203 faster lookups later.
5205 We use a small number because most searches fail (succeeding
5206 ultimately as the search bores through the inheritance
5207 hierarchy), and we want this failure to occur quickly. */
5211 {
5218 field_decl_cmp);
5222 }
5224 /* Complain if one of the field types requires lower visibility. */
5227 /* Make the rtl for any new vtables we have created, and unmark
5228 the base types we marked. */
5231 /* Build the VTT for T. */
5234 /* This warning does not make sense for Java classes, since they
5235 cannot have destructors. */
5237 {
5238 tree dtor;
5242 if it were virtual, we would have created it by now. */
5243 !dtor
5252 "%q#T has virtual functions and accessible"
5254 }
5261 /* Class layout, assignment of virtual table slots, etc., is now
5262 complete. Give the back end a chance to tweak the visibility of
5263 the class or perform any other required target modifications. */
5270 /* Finish debugging output for this type. */
5272 }
5274 /* When T was built up, the member declarations were added in reverse
5275 order. Rearrange them to declaration order. */
5277 void
5279 {
5280 tree next;
5281 tree prev;
5282 tree x;
5284 /* The following lists are all in reverse order. Put them in
5285 declaration order now. */
5289 /* Actually, for the TYPE_FIELDS, only the non TYPE_DECLs are in
5290 reverse order, so we can't just use nreverse. */
5295 {
5299 }
5301 {
5305 }
5306 }
5308 tree
5310 {
5313 /* Now that we've got all the field declarations, reverse everything
5314 as necessary. */
5319 /* Nadger the current location so that diagnostics point to the start of
5320 the struct, not the end. */
5324 {
5325 tree x;
5331 /* We need to emit an error message if this type was used as a parameter
5332 and it is an abstract type, even if it is a template. We construct
5333 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
5334 account and we call complete_vars with this type, which will check
5335 the PARM_DECLS. Note that while the type is being defined,
5336 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
5337 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
5343 }
5344 else
5353 else
5360 }
5361 \f
5362 /* Return the dynamic type of INSTANCE, if known.
5363 Used to determine whether the virtual function table is needed
5364 or not.
5366 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5367 of our knowledge of its type. *NONNULL should be initialized
5368 before this function is called. */
5370 static tree
5372 {
5373 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
5376 {
5380 else
5384 /* This is a call to a constructor, hence it's never zero. */
5386 {
5390 }
5394 /* This is a call to a constructor, hence it's never zero. */
5396 {
5400 }
5409 /* Propagate nonnull. */
5414 CASE_CONVERT:
5420 {
5421 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
5422 with a real object -- given &p->f, p can still be null. */
5424 /* ??? Probably should check DECL_WEAK here. */
5427 }
5431 /* If this component is really a base class reference, then the field
5432 itself isn't definitive. */
5441 {
5445 }
5446 /* fall through... */
5451 {
5455 }
5457 {
5461 /* if we're in a ctor or dtor, we know our type. */
5465 {
5469 }
5470 }
5472 {
5473 /* We only need one hash table because it is always left empty. */
5477 htab_hash_pointer,
5478 htab_eq_pointer,
5481 /* Reference variables should be references to objects. */
5485 /* Enter the INSTANCE in a table to prevent recursion; a
5486 variable's initializer may refer to the variable
5487 itself. */
5491 {
5492 tree type;
5501 }
5502 }
5507 }
5508 #undef RECUR
5509 }
5511 /* Return nonzero if the dynamic type of INSTANCE is known, and
5512 equivalent to the static type. We also handle the case where
5513 INSTANCE is really a pointer. Return negative if this is a
5514 ctor/dtor. There the dynamic type is known, but this might not be
5515 the most derived base of the original object, and hence virtual
5516 bases may not be layed out according to this type.
5518 Used to determine whether the virtual function table is needed
5519 or not.
5521 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
5522 of our knowledge of its type. *NONNULL should be initialized
5523 before this function is called. */
5525 int
5527 {
5538 }
5540 \f
5541 void
5543 {
5546 current_class_stack
5554 }
5556 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
5558 static void
5560 {
5561 tree type;
5563 /* We are re-entering the same class we just left, so we don't
5564 have to search the whole inheritance matrix to find all the
5565 decls to bind again. Instead, we install the cached
5566 class_shadowed list and walk through it binding names. */
5569 /* Restore IDENTIFIER_TYPE_VALUE. */
5571 type;
5574 }
5576 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
5577 appropriate for TYPE.
5579 So that we may avoid calls to lookup_name, we cache the _TYPE
5580 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
5582 For multiple inheritance, we perform a two-pass depth-first search
5583 of the type lattice. */
5585 void
5587 {
5588 class_stack_node_t csn;
5592 /* Make sure there is enough room for the new entry on the stack. */
5594 {
5596 current_class_stack
5598 current_class_stack_size);
5599 }
5601 /* Insert a new entry on the class stack. */
5608 current_class_depth++;
5610 /* Now set up the new type. */
5616 /* By default, things in classes are private, while things in
5617 structures or unions are public. */
5619 ? access_private_node
5625 {
5626 /* Forcibly remove any old class remnants. */
5628 }
5634 else
5636 }
5638 /* When we exit a toplevel class scope, we save its binding level so
5639 that we can restore it quickly. Here, we've entered some other
5640 class, so we must invalidate our cache. */
5642 void
5644 {
5646 }
5648 /* Get out of the current class scope. If we were in a class scope
5649 previously, that is the one popped to. */
5651 void
5653 {
5656 current_class_depth--;
5662 }
5664 /* Mark the top of the class stack as hidden. */
5666 void
5668 {
5671 }
5673 /* Mark the top of the class stack as un-hidden. */
5675 void
5677 {
5680 }
5682 /* Returns 1 if the class type currently being defined is either T or
5683 a nested type of T. */
5685 bool
5687 {
5690 /* We start looking from 1 because entry 0 is from global scope,
5691 and has no type. */
5693 {
5694 tree c;
5697 else
5698 {
5702 }
5707 }
5709 }
5711 /* If either current_class_type or one of its enclosing classes are derived
5712 from T, return the appropriate type. Used to determine how we found
5713 something via unqualified lookup. */
5715 tree
5717 {
5720 /* The bases of a dependent type are unknown. */
5731 {
5736 }
5739 }
5741 /* When entering a class scope, all enclosing class scopes' names with
5742 static meaning (static variables, static functions, types and
5743 enumerators) have to be visible. This recursive function calls
5744 pushclass for all enclosing class contexts until global or a local
5745 scope is reached. TYPE is the enclosed class. */
5747 void
5749 {
5750 /* A namespace might be passed in error cases, like A::B:C. */
5758 }
5760 /* Undoes a push_nested_class call. */
5762 void
5764 {
5770 }
5772 /* Returns the number of extern "LANG" blocks we are nested within. */
5774 int
5776 {
5778 }
5780 /* Set global variables CURRENT_LANG_NAME to appropriate value
5781 so that behavior of name-mangling machinery is correct. */
5783 void
5785 {
5789 {
5791 }
5793 {
5795 /* DECL_IGNORED_P is initially set for these types, to avoid clutter.
5796 (See record_builtin_java_type in decl.c.) However, that causes
5797 incorrect debug entries if these types are actually used.
5798 So we re-enable debug output after extern "Java". */
5807 }
5809 {
5811 }
5812 else
5814 }
5816 /* Get out of the current language scope. */
5818 void
5820 {
5822 }
5823 \f
5824 /* Type instantiation routines. */
5826 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
5827 matches the TARGET_TYPE. If there is no satisfactory match, return
5828 error_mark_node, and issue an error & warning messages under
5829 control of FLAGS. Permit pointers to member function if FLAGS
5830 permits. If TEMPLATE_ONLY, the name of the overloaded function was
5831 a template-id, and EXPLICIT_TARGS are the explicitly provided
5832 template arguments. If OVERLOAD is for one or more member
5833 functions, then ACCESS_PATH is the base path used to reference
5834 those member functions. */
5836 static tree
5838 tree overload,
5839 tsubst_flags_t flags,
5841 tree explicit_targs,
5842 tree access_path)
5843 {
5844 /* Here's what the standard says:
5846 [over.over]
5848 If the name is a function template, template argument deduction
5849 is done, and if the argument deduction succeeds, the deduced
5850 arguments are used to generate a single template function, which
5851 is added to the set of overloaded functions considered.
5853 Non-member functions and static member functions match targets of
5854 type "pointer-to-function" or "reference-to-function." Nonstatic
5855 member functions match targets of type "pointer-to-member
5856 function;" the function type of the pointer to member is used to
5857 select the member function from the set of overloaded member
5858 functions. If a nonstatic member function is selected, the
5859 reference to the overloaded function name is required to have the
5860 form of a pointer to member as described in 5.3.1.
5862 If more than one function is selected, any template functions in
5863 the set are eliminated if the set also contains a non-template
5864 function, and any given template function is eliminated if the
5865 set contains a second template function that is more specialized
5866 than the first according to the partial ordering rules 14.5.5.2.
5867 After such eliminations, if any, there shall remain exactly one
5868 selected function. */
5872 /* We store the matches in a TREE_LIST rooted here. The functions
5873 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
5874 interoperability with most_specialized_instantiation. */
5876 tree fn;
5878 /* By the time we get here, we should be seeing only real
5879 pointer-to-member types, not the internal POINTER_TYPE to
5880 METHOD_TYPE representation. */
5886 /* Check that the TARGET_TYPE is reasonable. */
5890 /* This is OK, too. */
5893 {
5894 /* This is OK, too. This comes from a conversion to reference
5895 type. */
5898 }
5899 else
5900 {
5906 }
5908 /* If we can find a non-template function that matches, we can just
5909 use it. There's no point in generating template instantiations
5910 if we're just going to throw them out anyhow. But, of course, we
5911 can only do this when we don't *need* a template function. */
5913 {
5914 tree fns;
5917 {
5919 tree fntype;
5922 /* We're not looking for templates just yet. */
5927 /* We're looking for a non-static member, and this isn't
5928 one, or vice versa. */
5931 /* Ignore functions which haven't been explicitly
5932 declared. */
5936 /* See if there's a match. */
5945 }
5946 }
5948 /* Now, if we've already got a match (or matches), there's no need
5949 to proceed to the template functions. But, if we don't have a
5950 match we need to look at them, too. */
5952 {
5953 tree target_fn_type;
5954 tree target_arg_types;
5955 tree target_ret_type;
5956 tree fns;
5959 target_fn_type
5961 else
5966 /* Never do unification on the 'this' parameter. */
5971 {
5973 tree instantiation;
5974 tree instantiation_type;
5975 tree targs;
5978 /* We're only looking for templates. */
5983 /* We're not looking for a non-static member, and this is
5984 one, or vice versa. */
5987 /* Try to do argument deduction. */
5992 /* Argument deduction failed. */
5995 /* Instantiate the template. */
5998 /* Instantiation failed. */
6001 /* See if there's a match. */
6004 instantiation_type =
6009 LOOKUP_NORMAL))
6011 }
6013 /* Now, remove all but the most specialized of the matches. */
6015 {
6020 NULL_TREE,
6021 NULL_TREE);
6022 }
6023 }
6025 /* Now we should have exactly one function in MATCHES. */
6027 {
6028 /* There were *no* matches. */
6030 {
6033 target_type);
6035 /* print_candidates expects a chain with the functions in
6036 TREE_VALUE slots, so we cons one up here (we're losing anyway,
6037 so why be clever?). */
6040 matches);
6043 }
6045 }
6047 {
6048 /* There were too many matches. */
6051 {
6052 tree match;
6056 target_type);
6058 /* Since print_candidates expects the functions in the
6059 TREE_VALUE slot, we flip them here. */
6064 }
6067 }
6069 /* Good, exactly one match. Now, convert it to the correct type. */
6074 {
6082 {
6085 }
6086 }
6088 /* If we're doing overload resolution purely for the purpose of
6089 determining conversion sequences, we should not consider the
6090 function used. If this conversion sequence is selected, the
6091 function will be marked as used at this point. */
6093 {
6095 /* We could not check access when this expression was originally
6096 created since we did not know at that time to which function
6097 the expression referred. */
6099 {
6102 }
6103 }
6107 else
6108 {
6109 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
6110 will mark the function as addressed, but here we must do it
6111 explicitly. */
6115 }
6116 }
6118 /* This function will instantiate the type of the expression given in
6119 RHS to match the type of LHSTYPE. If errors exist, then return
6120 error_mark_node. FLAGS is a bit mask. If TF_ERROR is set, then
6121 we complain on errors. If we are not complaining, never modify rhs,
6122 as overload resolution wants to try many possible instantiations, in
6123 the hope that at least one will work.
6125 For non-recursive calls, LHSTYPE should be a function, pointer to
6126 function, or a pointer to member function. */
6128 tree
6130 {
6137 {
6141 }
6144 {
6150 /* Microsoft allows `A::f' to be resolved to a
6151 pointer-to-member. */
6152 ;
6153 else
6154 {
6159 }
6160 }
6163 {
6166 }
6168 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
6169 deduce any type information. */
6171 {
6175 }
6177 /* There only a few kinds of expressions that may have a type
6178 dependent on overload resolution. */
6184 /* We don't overwrite rhs if it is an overloaded function.
6185 Copying it would destroy the tree link. */
6189 /* This should really only be used when attempting to distinguish
6190 what sort of a pointer to function we have. For now, any
6191 arithmetic operation which is not supported on pointers
6192 is rejected as an error. */
6195 {
6197 {
6203 /* Do not lose object's side effects. */
6207 }
6214 /* This can happen if we are forming a pointer-to-member for a
6215 member template. */
6218 /* Fall through. */
6221 {
6225 return
6229 }
6233 return
6237 access_path);
6253 {
6258 }
6265 }
6267 }
6268 \f
6269 /* Return the name of the virtual function pointer field
6270 (as an IDENTIFIER_NODE) for the given TYPE. Note that
6271 this may have to look back through base types to find the
6272 ultimate field name. (For single inheritance, these could
6273 all be the same name. Who knows for multiple inheritance). */
6275 static tree
6277 {
6284 {
6290 }
6298 }
6300 void
6302 {
6303 #ifdef GATHER_STATISTICS
6307 {
6312 }
6313 #endif
6314 }
6316 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
6317 according to [class]:
6318 The class-name is also inserted
6319 into the scope of the class itself. For purposes of access checking,
6320 the inserted class name is treated as if it were a public member name. */
6322 void
6324 {
6327 tree saved_cas;
6341 }
6343 /* Returns 1 if TYPE contains only padding bytes. */
6345 int
6347 {
6354 /* In G++ 3.2, whether or not a class was empty was determined by
6355 looking at its size. */
6358 else
6360 }
6362 /* Returns true if TYPE contains an empty class. */
6364 static bool
6366 {
6370 {
6371 tree field;
6372 tree binfo;
6373 tree base_binfo;
6385 }
6389 }
6391 /* Note that NAME was looked up while the current class was being
6392 defined and that the result of that lookup was DECL. */
6394 void
6396 {
6397 splay_tree names_used;
6399 /* If we're not defining a class, there's nothing to do. */
6404 /* If there's already a binding for this NAME, then we don't have
6405 anything to worry about. */
6418 }
6420 /* Note that NAME was declared (as DECL) in the current class. Check
6421 to see that the declaration is valid. */
6423 void
6425 {
6426 splay_tree names_used;
6427 splay_tree_node n;
6429 /* Look to see if we ever used this name. */
6430 names_used
6437 {
6438 /* [basic.scope.class]
6440 A name N used in a class S shall refer to the same declaration
6441 in its context and when re-evaluated in the completed scope of
6442 S. */
6446 }
6447 }
6449 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
6450 Secondary vtables are merged with primary vtables; this function
6451 will return the VAR_DECL for the primary vtable. */
6453 tree
6455 {
6456 tree decl;
6460 {
6463 }
6467 }
6470 /* Returns the binfo for the primary base of BINFO. If the resulting
6471 BINFO is a virtual base, and it is inherited elsewhere in the
6472 hierarchy, then the returned binfo might not be the primary base of
6473 BINFO in the complete object. Check BINFO_PRIMARY_P or
6474 BINFO_LOST_PRIMARY_P to be sure. */
6476 static tree
6478 {
6479 tree primary_base;
6486 }
6488 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
6490 static int
6492 {
6496 }
6498 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
6499 INDENT should be zero when called from the top level; it is
6500 incremented recursively. IGO indicates the next expected BINFO in
6501 inheritance graph ordering. */
6503 static tree
6506 tree binfo,
6507 tree igo,
6509 {
6511 tree base_binfo;
6519 {
6522 }
6537 {
6541 TFF_PLAIN_IDENTIFIER),
6543 }
6545 {
6548 }
6553 {
6557 {
6561 TFF_PLAIN_IDENTIFIER));
6562 }
6564 {
6568 TFF_PLAIN_IDENTIFIER));
6569 }
6571 {
6575 TFF_PLAIN_IDENTIFIER));
6576 }
6578 {
6582 TFF_PLAIN_IDENTIFIER));
6583 }
6587 }
6593 }
6595 /* Dump the BINFO hierarchy for T. */
6597 static void
6599 {
6611 }
6613 /* Debug interface to hierarchy dumping. */
6615 void
6617 {
6619 }
6621 static void
6623 {
6628 {
6631 }
6632 }
6634 static void
6636 {
6637 tree value;
6639 HOST_WIDE_INT elt;
6647 TFF_PLAIN_IDENTIFIER));
6654 }
6656 static void
6658 {
6666 {
6673 {
6677 }
6681 }
6684 }
6686 static void
6688 {
6696 {
6701 }
6704 }
6706 /* Dump a function or thunk and its thunkees. */
6708 static void
6710 {
6713 tree thunks;
6721 {
6731 else
6737 }
6741 }
6743 /* Dump the thunks for FN. */
6745 void
6747 {
6749 }
6751 /* Virtual function table initialization. */
6753 /* Create all the necessary vtables for T and its base classes. */
6755 static void
6757 {
6758 tree list;
6759 tree vbase;
6761 /* We lay out the primary and secondary vtables in one contiguous
6762 vtable. The primary vtable is first, followed by the non-virtual
6763 secondary vtables in inheritance graph order. */
6768 /* Then come the virtual bases, also in inheritance graph order. */
6770 {
6774 }
6778 }
6780 /* Initialize the vtable for BINFO with the INITS. */
6782 static void
6784 {
6785 tree decl;
6791 }
6793 /* Build the VTT (virtual table table) for T.
6794 A class requires a VTT if it has virtual bases.
6796 This holds
6797 1 - primary virtual pointer for complete object T
6798 2 - secondary VTTs for each direct non-virtual base of T which requires a
6799 VTT
6800 3 - secondary virtual pointers for each direct or indirect base of T which
6801 has virtual bases or is reachable via a virtual path from T.
6802 4 - secondary VTTs for each direct or indirect virtual base of T.
6804 Secondary VTTs look like complete object VTTs without part 4. */
6806 static void
6808 {
6809 tree inits;
6810 tree type;
6811 tree vtt;
6812 tree index;
6814 /* Build up the initializers for the VTT. */
6819 /* If we didn't need a VTT, we're done. */
6823 /* Figure out the type of the VTT. */
6827 /* Now, build the VTT object itself. */
6830 /* Add the VTT to the vtables list. */
6835 }
6837 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
6838 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
6839 and CHAIN the vtable pointer for this binfo after construction is
6840 complete. VALUE can also be another BINFO, in which case we recurse. */
6842 static tree
6844 {
6845 tree vt;
6848 {
6854 else
6856 }
6859 }
6861 /* Data for secondary VTT initialization. */
6863 {
6864 /* Is this the primary VTT? */
6867 /* Current index into the VTT. */
6868 tree index;
6870 /* TREE_LIST of initializers built up. */
6871 tree inits;
6873 /* The type being constructed by this secondary VTT. */
6874 tree type_being_constructed;
6877 /* Recursively build the VTT-initializer for BINFO (which is in the
6878 hierarchy dominated by T). INITS points to the end of the initializer
6879 list to date. INDEX is the VTT index where the next element will be
6880 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
6881 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
6882 for virtual bases of T. When it is not so, we build the constructor
6883 vtables for the BINFO-in-T variant. */
6887 {
6889 tree b;
6890 tree init;
6891 tree secondary_vptrs;
6892 secondary_vptr_vtt_init_data data;
6895 /* We only need VTTs for subobjects with virtual bases. */
6899 /* We need to use a construction vtable if this is not the primary
6900 VTT. */
6902 {
6905 /* Record the offset in the VTT where this sub-VTT can be found. */
6907 }
6909 /* Add the address of the primary vtable for the complete object. */
6914 {
6917 }
6920 /* Recursively add the secondary VTTs for non-virtual bases. */
6925 /* Add secondary virtual pointers for all subobjects of BINFO with
6926 either virtual bases or reachable along a virtual path, except
6927 subobjects that are non-virtual primary bases. */
6937 /* The secondary vptrs come back in reverse order. After we reverse
6938 them, and add the INITS, the last init will be the first element
6939 of the chain. */
6942 {
6946 }
6949 /* Add the secondary VTTs for virtual bases in inheritance graph
6950 order. */
6952 {
6957 }
6958 else
6959 /* Remove the ctor vtables we created. */
6963 }
6965 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
6966 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
6968 static tree
6970 {
6973 /* We don't care about bases that don't have vtables. */
6977 /* We're only interested in proper subobjects of the type being
6978 constructed. */
6982 /* We're only interested in bases with virtual bases or reachable
6983 via a virtual path from the type being constructed. */
6988 /* We're not interested in non-virtual primary bases. */
6992 /* Record the index where this secondary vptr can be found. */
6994 {
6999 {
7000 /* It's a primary virtual base, and this is not a
7001 construction vtable. Find the base this is primary of in
7002 the inheritance graph, and use that base's vtable
7003 now. */
7006 }
7007 }
7009 /* Add the initializer for the secondary vptr itself. */
7012 /* Advance the vtt index. */
7017 }
7019 /* Called from build_vtt_inits via dfs_walk. After building
7020 constructor vtables and generating the sub-vtt from them, we need
7021 to restore the BINFO_VTABLES that were scribbled on. DATA is the
7022 binfo of the base whose sub vtt was generated. */
7024 static tree
7026 {
7030 /* If this class has no vtable, none of its bases do. */
7034 /* This might be a primary base, so have no vtable in this
7035 hierarchy. */
7038 /* If we scribbled the construction vtable vptr into BINFO, clear it
7039 out now. */
7045 }
7047 /* Build the construction vtable group for BINFO which is in the
7048 hierarchy dominated by T. */
7050 static void
7052 {
7053 tree list;
7054 tree type;
7055 tree vtbl;
7056 tree inits;
7057 tree id;
7058 tree vbase;
7060 /* See if we've already created this construction vtable group. */
7066 /* Build a version of VTBL (with the wrong type) for use in
7067 constructing the addresses of secondary vtables in the
7068 construction vtable group. */
7075 /* Add the vtables for each of our virtual bases using the vbase in T
7076 binfo. */
7078 vbase;
7080 {
7081 tree b;
7088 }
7091 /* Figure out the type of the construction vtable. */
7099 /* Initialize the construction vtable. */
7103 }
7105 /* Add the vtbl initializers for BINFO (and its bases other than
7106 non-virtual primaries) to the list of INITS. BINFO is in the
7107 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
7108 the constructor the vtbl inits should be accumulated for. (If this
7109 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
7110 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
7111 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
7112 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
7113 but are not necessarily the same in terms of layout. */
7115 static void
7117 tree orig_binfo,
7118 tree rtti_binfo,
7119 tree t,
7120 tree inits)
7121 {
7123 tree base_binfo;
7128 /* If it doesn't have a vptr, we don't do anything. */
7132 /* If we're building a construction vtable, we're not interested in
7133 subobjects that don't require construction vtables. */
7139 /* Build the initializers for the BINFO-in-T vtable. */
7145 /* Walk the BINFO and its bases. We walk in preorder so that as we
7146 initialize each vtable we can figure out at what offset the
7147 secondary vtable lies from the primary vtable. We can't use
7148 dfs_walk here because we need to iterate through bases of BINFO
7149 and RTTI_BINFO simultaneously. */
7151 {
7152 /* Skip virtual bases. */
7158 inits);
7159 }
7160 }
7162 /* Called from accumulate_vtbl_inits. Returns the initializers for
7163 the BINFO vtable. */
7165 static tree
7167 tree orig_binfo,
7168 tree rtti_binfo,
7169 tree t,
7170 tree l)
7171 {
7178 {
7179 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
7180 primary virtual base. If it is not the same primary in
7181 the hierarchy of T, we'll need to generate a ctor vtable
7182 for it, to place at its location in T. If it is the same
7183 primary, we still need a VTT entry for the vtable, but it
7184 should point to the ctor vtable for the base it is a
7185 primary for within the sub-hierarchy of RTTI_BINFO.
7187 There are three possible cases:
7189 1) We are in the same place.
7190 2) We are a primary base within a lost primary virtual base of
7191 RTTI_BINFO.
7192 3) We are primary to something not a base of RTTI_BINFO. */
7194 tree b;
7197 /* First, look through the bases we are primary to for RTTI_BINFO
7198 or a virtual base. */
7201 {
7206 }
7207 /* If we run out of primary links, keep looking down our
7208 inheritance chain; we might be an indirect primary. */
7212 found:
7214 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
7215 base B and it is a base of RTTI_BINFO, this is case 2. In
7216 either case, we share our vtable with LAST, i.e. the
7217 derived-most base within B of which we are a primary. */
7220 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
7221 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
7222 binfo_ctor_vtable after everything's been set up. */
7225 /* Otherwise, this is case 3 and we get our own. */
7226 }
7231 {
7232 tree index;
7235 /* Compute the initializer for this vtable. */
7239 /* Figure out the position to which the VPTR should point. */
7247 index);
7249 }
7252 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
7253 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
7254 straighten this out. */
7258 else
7259 /* For an ordinary vtable, set BINFO_VTABLE. */
7263 }
7267 /* Construct the initializer for BINFO's virtual function table. BINFO
7268 is part of the hierarchy dominated by T. If we're building a
7269 construction vtable, the ORIG_BINFO is the binfo we should use to
7270 find the actual function pointers to put in the vtable - but they
7271 can be overridden on the path to most-derived in the graph that
7272 ORIG_BINFO belongs. Otherwise,
7273 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
7274 BINFO that should be indicated by the RTTI information in the
7275 vtable; it will be a base class of T, rather than T itself, if we
7276 are building a construction vtable.
7278 The value returned is a TREE_LIST suitable for wrapping in a
7279 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
7280 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
7281 number of non-function entries in the vtable.
7283 It might seem that this function should never be called with a
7284 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
7285 base is always subsumed by a derived class vtable. However, when
7286 we are building construction vtables, we do build vtables for
7287 primary bases; we need these while the primary base is being
7288 constructed. */
7290 static tree
7292 tree orig_binfo,
7293 tree t,
7294 tree rtti_binfo,
7296 {
7298 tree vfun_inits;
7299 vtbl_init_data vid;
7301 tree vbinfo;
7304 /* Initialize VID. */
7313 /* The first vbase or vcall offset is at index -3 in the vtable. */
7316 /* Add entries to the vtable for RTTI. */
7319 /* Create an array for keeping track of the functions we've
7320 processed. When we see multiple functions with the same
7321 signature, we share the vcall offsets. */
7323 /* Add the vcall and vbase offset entries. */
7326 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
7327 build_vbase_offset_vtbl_entries. */
7332 /* If the target requires padding between data entries, add that now. */
7334 {
7338 {
7345 null_pointer_node),
7346 add);
7348 }
7349 }
7354 /* Go through all the ordinary virtual functions, building up
7355 initializers. */
7358 {
7359 tree delta;
7360 tree vcall_index;
7367 {
7371 {
7374 }
7376 }
7378 /* If the only definition of this function signature along our
7379 primary base chain is from a lost primary, this vtable slot will
7380 never be used, so just zero it out. This is important to avoid
7381 requiring extra thunks which cannot be generated with the function.
7383 We first check this in update_vtable_entry_for_fn, so we handle
7384 restored primary bases properly; we also need to do it here so we
7385 zero out unused slots in ctor vtables, rather than filling themff
7386 with erroneous values (though harmless, apart from relocation
7387 costs). */
7389 {
7390 /* We found a defn before a lost primary; go ahead as normal. */
7394 /* The nearest definition is from a lost primary; clear the
7395 slot. */
7397 {
7400 }
7401 }
7404 {
7405 /* Pull the offset for `this', and the function to call, out of
7406 the list. */
7413 /* You can't call an abstract virtual function; it's abstract.
7414 So, we replace these functions with __pure_virtual. */
7416 {
7421 }
7422 else
7423 {
7425 {
7429 }
7430 /* Take the address of the function, considering it to be of an
7431 appropriate generic type. */
7433 }
7434 }
7436 /* And add it to the chain of initializers. */
7438 {
7443 else
7445 {
7452 }
7453 }
7454 else
7456 }
7458 /* The initializers for virtual functions were built up in reverse
7459 order; straighten them out now. */
7462 /* The negative offset initializers are also in reverse order. */
7465 /* Chain the two together. */
7467 }
7469 /* Adds to vid->inits the initializers for the vbase and vcall
7470 offsets in BINFO, which is in the hierarchy dominated by T. */
7472 static void
7474 {
7475 tree b;
7477 /* If this is a derived class, we must first create entries
7478 corresponding to the primary base class. */
7483 /* Add the vbase entries for this base. */
7485 /* Add the vcall entries for this base. */
7487 }
7489 /* Returns the initializers for the vbase offset entries in the vtable
7490 for BINFO (which is part of the class hierarchy dominated by T), in
7491 reverse order. VBASE_OFFSET_INDEX gives the vtable index
7492 where the next vbase offset will go. */
7494 static void
7496 {
7497 tree vbase;
7498 tree t;
7499 tree non_primary_binfo;
7501 /* If there are no virtual baseclasses, then there is nothing to
7502 do. */
7508 /* We might be a primary base class. Go up the inheritance hierarchy
7509 until we find the most derived class of which we are a primary base:
7510 it is the offset of that which we need to use. */
7513 {
7514 tree b;
7516 /* If we have reached a virtual base, then it must be a primary
7517 base (possibly multi-level) of vid->binfo, or we wouldn't
7518 have called build_vcall_and_vbase_vtbl_entries for it. But it
7519 might be a lost primary, so just skip down to vid->binfo. */
7521 {
7524 }
7530 }
7532 /* Go through the virtual bases, adding the offsets. */
7534 vbase;
7536 {
7537 tree b;
7538 tree delta;
7543 /* Find the instance of this virtual base in the complete
7544 object. */
7547 /* If we've already got an offset for this virtual base, we
7548 don't need another one. */
7553 /* Figure out where we can find this vbase offset. */
7562 /* The vbase offset had better be the same. */
7565 /* The next vbase will come at a more negative offset. */
7569 /* The initializer is the delta from BINFO to this virtual base.
7570 The vbase offsets go in reverse inheritance-graph order, and
7571 we are walking in inheritance graph order so these end up in
7572 the right order. */
7578 vtable_entry_type,
7579 delta));
7581 }
7582 }
7584 /* Adds the initializers for the vcall offset entries in the vtable
7585 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
7586 to VID->INITS. */
7588 static void
7590 {
7591 /* We only need these entries if this base is a virtual base. We
7592 compute the indices -- but do not add to the vtable -- when
7593 building the main vtable for a class. */
7596 /* If BINFO is RTTI_BINFO, then (since BINFO does not
7597 correspond to VID->DERIVED), we are building a primary
7598 construction virtual table. Since this is a primary
7599 virtual table, we do not need the vcall offsets for
7600 BINFO. */
7602 {
7603 /* We need a vcall offset for each of the virtual functions in this
7604 vtable. For example:
7606 class A { virtual void f (); };
7607 class B1 : virtual public A { virtual void f (); };
7608 class B2 : virtual public A { virtual void f (); };
7609 class C: public B1, public B2 { virtual void f (); };
7611 A C object has a primary base of B1, which has a primary base of A. A
7612 C also has a secondary base of B2, which no longer has a primary base
7613 of A. So the B2-in-C construction vtable needs a secondary vtable for
7614 A, which will adjust the A* to a B2* to call f. We have no way of
7615 knowing what (or even whether) this offset will be when we define B2,
7616 so we store this "vcall offset" in the A sub-vtable and look it up in
7617 a "virtual thunk" for B2::f.
7619 We need entries for all the functions in our primary vtable and
7620 in our non-virtual bases' secondary vtables. */
7622 /* If we are just computing the vcall indices -- but do not need
7623 the actual entries -- not that. */
7626 /* Now, walk through the non-virtual bases, adding vcall offsets. */
7628 }
7629 }
7631 /* Build vcall offsets, starting with those for BINFO. */
7633 static void
7635 {
7637 tree primary_binfo;
7638 tree base_binfo;
7640 /* Don't walk into virtual bases -- except, of course, for the
7641 virtual base for which we are building vcall offsets. Any
7642 primary virtual base will have already had its offsets generated
7643 through the recursion in build_vcall_and_vbase_vtbl_entries. */
7647 /* If BINFO has a primary base, process it first. */
7652 /* Add BINFO itself to the list. */
7655 /* Scan the non-primary bases of BINFO. */
7659 }
7661 /* Called from build_vcall_offset_vtbl_entries_r. */
7663 static void
7665 {
7666 /* Make entries for the rest of the virtuals. */
7668 {
7669 tree orig_fn;
7671 /* The ABI requires that the methods be processed in declaration
7672 order. G++ 3.2 used the order in the vtable. */
7674 orig_fn;
7678 }
7679 else
7680 {
7681 tree derived_virtuals;
7682 tree base_virtuals;
7683 tree orig_virtuals;
7684 /* If BINFO is a primary base, the most derived class which has
7685 BINFO as a primary base; otherwise, just BINFO. */
7686 tree non_primary_binfo;
7688 /* We might be a primary base class. Go up the inheritance hierarchy
7689 until we find the most derived class of which we are a primary base:
7690 it is the BINFO_VIRTUALS there that we need to consider. */
7693 {
7694 tree b;
7696 /* If we have reached a virtual base, then it must be vid->vbase,
7697 because we ignore other virtual bases in
7698 add_vcall_offset_vtbl_entries_r. In turn, it must be a primary
7699 base (possibly multi-level) of vid->binfo, or we wouldn't
7700 have called build_vcall_and_vbase_vtbl_entries for it. But it
7701 might be a lost primary, so just skip down to vid->binfo. */
7703 {
7707 }
7713 }
7716 /* For a ctor vtable we need the equivalent binfo within the hierarchy
7717 where rtti_binfo is the most derived type. */
7718 non_primary_binfo
7724 base_virtuals;
7728 {
7729 tree orig_fn;
7731 /* Find the declaration that originally caused this function to
7732 be present in BINFO_TYPE (binfo). */
7735 /* When processing BINFO, we only want to generate vcall slots for
7736 function slots introduced in BINFO. So don't try to generate
7737 one if the function isn't even defined in BINFO. */
7742 }
7743 }
7744 }
7746 /* Add a vcall offset entry for ORIG_FN to the vtable. */
7748 static void
7750 {
7752 tree vcall_offset;
7753 tree derived_entry;
7755 /* If there is already an entry for a function with the same
7756 signature as FN, then we do not need a second vcall offset.
7757 Check the list of functions already present in the derived
7758 class vtable. */
7760 {
7762 /* We only use one vcall offset for virtual destructors,
7763 even though there are two virtual table entries. */
7767 }
7769 /* If we are building these vcall offsets as part of building
7770 the vtable for the most derived class, remember the vcall
7771 offset. */
7773 {
7776 NULL);
7779 }
7781 /* The next vcall offset will be found at a more negative
7782 offset. */
7786 /* Keep track of this function. */
7790 {
7791 tree base;
7792 tree fn;
7794 /* Find the overriding function. */
7798 integer_zero_node);
7799 else
7800 {
7803 /* The vbase we're working on is a primary base of
7804 vid->binfo. But it might be a lost primary, so its
7805 BINFO_OFFSET might be wrong, so we just use the
7806 BINFO_OFFSET from vid->binfo. */
7810 vcall_offset);
7811 }
7812 /* Add the initializer to the vtable. */
7815 }
7816 }
7818 /* Return vtbl initializers for the RTTI entries corresponding to the
7819 BINFO's vtable. The RTTI entries should indicate the object given
7820 by VID->rtti_binfo. */
7822 static void
7824 {
7825 tree b;
7826 tree t;
7827 tree basetype;
7828 tree offset;
7829 tree decl;
7830 tree init;
7835 /* To find the complete object, we will first convert to our most
7836 primary base, and then add the offset in the vtbl to that value. */
7840 {
7841 tree primary_base;
7847 }
7850 /* The second entry is the address of the typeinfo object. */
7853 else
7856 /* Convert the declaration to a type that can be stored in the
7857 vtable. */
7862 /* Add the offset-to-top entry. It comes earlier in the vtable than
7863 the typeinfo entry. Convert the offset to look like a
7864 function pointer, so that we can put it in the vtable. */
7868 }
7870 /* Fold a OBJ_TYPE_REF expression to the address of a function.
7871 KNOWN_TYPE carries the true type of OBJ_TYPE_REF_OBJECT(REF). */
7873 tree
7875 {
7879 tree fndecl;
7882 {
7883 i += (TARGET_VTABLE_USES_DESCRIPTORS
7886 }
7890 #ifdef ENABLE_CHECKING
7893 #endif
7898 }