1 /* RunTime Type Identification
2 Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
4 Free Software Foundation, Inc.
5 Mostly written by Jason Merrill (jason@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)
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/>. */
25 #include "coretypes.h"
37 /* C++ returns type information to the user in struct type_info
38 objects. We also use type information to implement dynamic_cast and
39 exception handlers. Type information for a particular type is
40 indicated with an ABI defined structure derived from type_info.
41 This would all be very straight forward, but for the fact that the
42 runtime library provides the definitions of the type_info structure
43 and the ABI defined derived classes. We cannot build declarations
44 of them directly in the compiler, but we need to layout objects of
45 their type. Somewhere we have to lie.
47 We define layout compatible POD-structs with compiler-defined names
48 and generate the appropriate initializations for them (complete
49 with explicit mention of their vtable). When we have to provide a
50 type_info to the user we reinterpret_cast the internal compiler
51 type to type_info. A well formed program can only explicitly refer
52 to the type_infos of complete types (& cv void). However, we chain
53 pointer type_infos to the pointed-to-type, and that can be
54 incomplete. We only need the addresses of such incomplete
55 type_info objects for static initialization.
57 The type information VAR_DECL of a type is held on the
58 IDENTIFIER_GLOBAL_VALUE of the type's mangled name. That VAR_DECL
59 will be the internal type. It will usually have the correct
60 internal type reflecting the kind of type it represents (pointer,
61 array, function, class, inherited class, etc). When the type it
62 represents is incomplete, it will have the internal type
63 corresponding to type_info. That will only happen at the end of
64 translation, when we are emitting the type info objects. */
66 /* Auxiliary data we hold for each type_info derived object we need. */
67 typedef struct tinfo_s GTY (())
69 tree type; /* The RECORD_TYPE for this type_info object */
71 tree vtable; /* The VAR_DECL of the vtable. Only filled at end of
74 tree name; /* IDENTIFIER_NODE for the ABI specified name of
75 the type_info derived type. */
79 DEF_VEC_ALLOC_O(tinfo_s,gc);
81 typedef enum tinfo_kind
83 TK_TYPE_INFO_TYPE, /* abi::__type_info_pseudo */
84 TK_BASE_TYPE, /* abi::__base_class_type_info */
85 TK_BUILTIN_TYPE, /* abi::__fundamental_type_info */
86 TK_ARRAY_TYPE, /* abi::__array_type_info */
87 TK_FUNCTION_TYPE, /* abi::__function_type_info */
88 TK_ENUMERAL_TYPE, /* abi::__enum_type_info */
89 TK_POINTER_TYPE, /* abi::__pointer_type_info */
90 TK_POINTER_MEMBER_TYPE, /* abi::__pointer_to_member_type_info */
91 TK_CLASS_TYPE, /* abi::__class_type_info */
92 TK_SI_CLASS_TYPE, /* abi::__si_class_type_info */
93 TK_FIXED /* end of fixed descriptors. */
94 /* ... abi::__vmi_type_info<I> */
97 /* A vector of all tinfo decls that haven't yet been emitted. */
98 VEC(tree,gc) *unemitted_tinfo_decls;
100 /* A vector of all type_info derived types we need. The first few are
101 fixed and created early. The remainder are for multiple inheritance
102 and are generated as needed. */
103 static GTY (()) VEC(tinfo_s,gc) *tinfo_descs;
105 static tree ifnonnull (tree, tree);
106 static tree tinfo_name (tree);
107 static tree build_dynamic_cast_1 (tree, tree, tsubst_flags_t);
108 static tree throw_bad_cast (void);
109 static tree throw_bad_typeid (void);
110 static tree get_tinfo_decl_dynamic (tree);
111 static tree get_tinfo_ptr (tree);
112 static bool typeid_ok_p (void);
113 static int qualifier_flags (tree);
114 static bool target_incomplete_p (tree);
115 static tree tinfo_base_init (tinfo_s *, tree);
116 static tree generic_initializer (tinfo_s *, tree);
117 static tree ptr_initializer (tinfo_s *, tree);
118 static tree ptm_initializer (tinfo_s *, tree);
119 static tree class_initializer (tinfo_s *, tree, tree);
120 static void create_pseudo_type_info (int, const char *, ...);
121 static tree get_pseudo_ti_init (tree, unsigned);
122 static unsigned get_pseudo_ti_index (tree);
123 static void create_tinfo_types (void);
124 static bool typeinfo_in_lib_p (tree);
126 static int doing_runtime = 0;
129 push_abi_namespace (void)
131 push_nested_namespace (abi_node);
132 push_visibility ("default");
136 pop_abi_namespace (void)
139 pop_nested_namespace (abi_node);
142 /* Declare language defined type_info type and a pointer to const
143 type_info. This is incomplete here, and will be completed when
144 the user #includes <typeinfo>. There are language defined
145 restrictions on what can be done until that is included. Create
146 the internal versions of the ABI types. */
149 init_rtti_processing (void)
153 push_namespace (std_identifier);
154 type_info_type = xref_tag (class_type, get_identifier ("type_info"),
155 /*tag_scope=*/ts_current, false);
157 const_type_info_type_node
158 = build_qualified_type (type_info_type, TYPE_QUAL_CONST);
159 type_info_ptr_type = build_pointer_type (const_type_info_type_node);
161 unemitted_tinfo_decls = VEC_alloc (tree, gc, 124);
163 create_tinfo_types ();
166 /* Given the expression EXP of type `class *', return the head of the
167 object pointed to by EXP with type cv void*, if the class has any
168 virtual functions (TYPE_POLYMORPHIC_P), else just return the
172 build_headof (tree exp)
174 tree type = TREE_TYPE (exp);
178 gcc_assert (TREE_CODE (type) == POINTER_TYPE);
179 type = TREE_TYPE (type);
181 if (!TYPE_POLYMORPHIC_P (type))
184 /* We use this a couple of times below, protect it. */
185 exp = save_expr (exp);
187 /* The offset-to-top field is at index -2 from the vptr. */
188 index = build_int_cst (NULL_TREE,
189 -2 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);
191 offset = build_vtbl_ref (cp_build_indirect_ref (exp, NULL,
192 tf_warning_or_error),
195 type = build_qualified_type (ptr_type_node,
196 cp_type_quals (TREE_TYPE (exp)));
197 return build2 (POINTER_PLUS_EXPR, type, exp,
198 convert_to_integer (sizetype, offset));
201 /* Get a bad_cast node for the program to throw...
203 See libstdc++/exception.cc for __throw_bad_cast */
206 throw_bad_cast (void)
208 tree fn = get_identifier ("__cxa_bad_cast");
209 if (!get_global_value_if_present (fn, &fn))
210 fn = push_throw_library_fn (fn, build_function_type (ptr_type_node,
213 return build_cxx_call (fn, 0, NULL);
216 /* Return an expression for "__cxa_bad_typeid()". The expression
217 returned is an lvalue of type "const std::type_info". */
220 throw_bad_typeid (void)
222 tree fn = get_identifier ("__cxa_bad_typeid");
223 if (!get_global_value_if_present (fn, &fn))
227 t = build_reference_type (const_type_info_type_node);
228 t = build_function_type (t, void_list_node);
229 fn = push_throw_library_fn (fn, t);
232 return build_cxx_call (fn, 0, NULL);
235 /* Return an lvalue expression whose type is "const std::type_info"
236 and whose value indicates the type of the expression EXP. If EXP
237 is a reference to a polymorphic class, return the dynamic type;
238 otherwise return the static type of the expression. */
241 get_tinfo_decl_dynamic (tree exp)
246 if (error_operand_p (exp))
247 return error_mark_node;
249 /* peel back references, so they match. */
250 type = non_reference (TREE_TYPE (exp));
252 /* Peel off cv qualifiers. */
253 type = TYPE_MAIN_VARIANT (type);
255 /* For UNKNOWN_TYPEs call complete_type_or_else to get diagnostics. */
256 if (CLASS_TYPE_P (type) || TREE_CODE (type) == UNKNOWN_TYPE)
257 type = complete_type_or_else (type, exp);
260 return error_mark_node;
262 /* If exp is a reference to polymorphic type, get the real type_info. */
263 if (TYPE_POLYMORPHIC_P (type) && ! resolves_to_fixed_type_p (exp, 0))
265 /* build reference to type_info from vtable. */
268 /* The RTTI information is at index -1. */
269 index = build_int_cst (NULL_TREE,
270 -1 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);
271 t = build_vtbl_ref (exp, index);
272 t = convert (type_info_ptr_type, t);
275 /* Otherwise return the type_info for the static type of the expr. */
276 t = get_tinfo_ptr (TYPE_MAIN_VARIANT (type));
278 return cp_build_indirect_ref (t, NULL, tf_warning_or_error);
284 tree pseudo_type_info, type_info_type;
288 error ("cannot use typeid with -fno-rtti");
292 if (!COMPLETE_TYPE_P (const_type_info_type_node))
294 error ("must #include <typeinfo> before using typeid");
299 = VEC_index (tinfo_s, tinfo_descs, TK_TYPE_INFO_TYPE)->type;
300 type_info_type = TYPE_MAIN_VARIANT (const_type_info_type_node);
302 /* Make sure abi::__type_info_pseudo has the same alias set
303 as std::type_info. */
304 if (! TYPE_ALIAS_SET_KNOWN_P (pseudo_type_info))
305 TYPE_ALIAS_SET (pseudo_type_info) = get_alias_set (type_info_type);
307 gcc_assert (TYPE_ALIAS_SET (pseudo_type_info)
308 == get_alias_set (type_info_type));
313 /* Return an expression for "typeid(EXP)". The expression returned is
314 an lvalue of type "const std::type_info". */
317 build_typeid (tree exp)
319 tree cond = NULL_TREE;
322 if (exp == error_mark_node || !typeid_ok_p ())
323 return error_mark_node;
325 if (processing_template_decl)
326 return build_min (TYPEID_EXPR, const_type_info_type_node, exp);
328 if (TREE_CODE (exp) == INDIRECT_REF
329 && TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == POINTER_TYPE
330 && TYPE_POLYMORPHIC_P (TREE_TYPE (exp))
331 && ! resolves_to_fixed_type_p (exp, &nonnull)
334 exp = stabilize_reference (exp);
335 cond = cp_convert (boolean_type_node, TREE_OPERAND (exp, 0));
338 exp = get_tinfo_decl_dynamic (exp);
340 if (exp == error_mark_node)
341 return error_mark_node;
345 tree bad = throw_bad_typeid ();
347 exp = build3 (COND_EXPR, TREE_TYPE (exp), cond, exp, bad);
353 /* Generate the NTBS name of a type. */
355 tinfo_name (tree type)
360 name = mangle_type_string (type);
361 name_string = fix_string_type (build_string (strlen (name) + 1, name));
365 /* Return a VAR_DECL for the internal ABI defined type_info object for
366 TYPE. You must arrange that the decl is mark_used, if actually use
367 it --- decls in vtables are only used if the vtable is output. */
370 get_tinfo_decl (tree type)
375 if (variably_modified_type_p (type, /*fn=*/NULL_TREE))
377 error ("cannot create type information for type %qT because "
378 "it involves types of variable size",
380 return error_mark_node;
383 if (TREE_CODE (type) == METHOD_TYPE)
384 type = build_function_type (TREE_TYPE (type),
385 TREE_CHAIN (TYPE_ARG_TYPES (type)));
387 /* For a class type, the variable is cached in the type node
389 if (CLASS_TYPE_P (type))
391 d = CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type));
396 name = mangle_typeinfo_for_type (type);
398 d = IDENTIFIER_GLOBAL_VALUE (name);
401 int ix = get_pseudo_ti_index (type);
402 tinfo_s *ti = VEC_index (tinfo_s, tinfo_descs, ix);
404 d = build_lang_decl (VAR_DECL, name, ti->type);
405 SET_DECL_ASSEMBLER_NAME (d, name);
406 /* Remember the type it is for. */
407 TREE_TYPE (name) = type;
408 DECL_TINFO_P (d) = 1;
409 DECL_ARTIFICIAL (d) = 1;
410 DECL_IGNORED_P (d) = 1;
411 TREE_READONLY (d) = 1;
413 /* Mark the variable as undefined -- but remember that we can
414 define it later if we need to do so. */
415 DECL_EXTERNAL (d) = 1;
416 DECL_NOT_REALLY_EXTERN (d) = 1;
417 set_linkage_according_to_type (type, d);
419 d = pushdecl_top_level_and_finish (d, NULL_TREE);
420 if (CLASS_TYPE_P (type))
421 CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type)) = d;
423 /* Add decl to the global array of tinfo decls. */
424 VEC_safe_push (tree, gc, unemitted_tinfo_decls, d);
430 /* Return a pointer to a type_info object describing TYPE, suitably
431 cast to the language defined type. */
434 get_tinfo_ptr (tree type)
436 tree decl = get_tinfo_decl (type);
439 return build_nop (type_info_ptr_type,
440 build_address (decl));
443 /* Return the type_info object for TYPE. */
446 get_typeid (tree type)
448 if (type == error_mark_node || !typeid_ok_p ())
449 return error_mark_node;
451 if (processing_template_decl)
452 return build_min (TYPEID_EXPR, const_type_info_type_node, type);
454 /* If the type of the type-id is a reference type, the result of the
455 typeid expression refers to a type_info object representing the
457 type = non_reference (type);
459 /* The top-level cv-qualifiers of the lvalue expression or the type-id
460 that is the operand of typeid are always ignored. */
461 type = TYPE_MAIN_VARIANT (type);
463 /* For UNKNOWN_TYPEs call complete_type_or_else to get diagnostics. */
464 if (CLASS_TYPE_P (type) || TREE_CODE (type) == UNKNOWN_TYPE)
465 type = complete_type_or_else (type, NULL_TREE);
468 return error_mark_node;
470 return cp_build_indirect_ref (get_tinfo_ptr (type), NULL,
471 tf_warning_or_error);
474 /* Check whether TEST is null before returning RESULT. If TEST is used in
475 RESULT, it must have previously had a save_expr applied to it. */
478 ifnonnull (tree test, tree result)
480 return build3 (COND_EXPR, TREE_TYPE (result),
481 build2 (EQ_EXPR, boolean_type_node, test,
482 cp_convert (TREE_TYPE (test), integer_zero_node)),
483 cp_convert (TREE_TYPE (result), integer_zero_node),
487 /* Execute a dynamic cast, as described in section 5.2.6 of the 9/93 working
491 build_dynamic_cast_1 (tree type, tree expr, tsubst_flags_t complain)
493 enum tree_code tc = TREE_CODE (type);
494 tree exprtype = TREE_TYPE (expr);
496 tree old_expr = expr;
497 const char *errstr = NULL;
499 /* Save casted types in the function's used types hash table. */
500 used_types_insert (type);
502 /* T shall be a pointer or reference to a complete class type, or
503 `pointer to cv void''. */
507 if (TREE_CODE (TREE_TYPE (type)) == VOID_TYPE)
511 if (! MAYBE_CLASS_TYPE_P (TREE_TYPE (type)))
513 errstr = "target is not pointer or reference to class";
516 if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (type))))
518 errstr = "target is not pointer or reference to complete type";
524 errstr = "target is not pointer or reference";
528 if (tc == POINTER_TYPE)
530 /* If T is a pointer type, v shall be an rvalue of a pointer to
531 complete class type, and the result is an rvalue of type T. */
533 if (TREE_CODE (exprtype) != POINTER_TYPE)
535 errstr = "source is not a pointer";
538 if (! MAYBE_CLASS_TYPE_P (TREE_TYPE (exprtype)))
540 errstr = "source is not a pointer to class";
543 if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (exprtype))))
545 errstr = "source is a pointer to incomplete type";
551 exprtype = build_reference_type (exprtype);
553 /* T is a reference type, v shall be an lvalue of a complete class
554 type, and the result is an lvalue of the type referred to by T. */
556 if (! MAYBE_CLASS_TYPE_P (TREE_TYPE (exprtype)))
558 errstr = "source is not of class type";
561 if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (exprtype))))
563 errstr = "source is of incomplete class type";
567 /* Apply trivial conversion T -> T& for dereferenced ptrs. */
568 expr = convert_to_reference (exprtype, expr, CONV_IMPLICIT,
569 LOOKUP_NORMAL, NULL_TREE);
572 /* The dynamic_cast operator shall not cast away constness. */
573 if (!at_least_as_qualified_p (TREE_TYPE (type),
574 TREE_TYPE (exprtype)))
576 errstr = "conversion casts away constness";
580 /* If *type is an unambiguous accessible base class of *exprtype,
581 convert statically. */
585 binfo = lookup_base (TREE_TYPE (exprtype), TREE_TYPE (type),
590 expr = build_base_path (PLUS_EXPR, convert_from_reference (expr),
592 if (TREE_CODE (exprtype) == POINTER_TYPE)
593 expr = rvalue (expr);
598 /* Otherwise *exprtype must be a polymorphic class (have a vtbl). */
599 if (TYPE_POLYMORPHIC_P (TREE_TYPE (exprtype)))
602 /* if TYPE is `void *', return pointer to complete object. */
603 if (tc == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (type)))
605 /* if b is an object, dynamic_cast<void *>(&b) == (void *)&b. */
606 if (TREE_CODE (expr) == ADDR_EXPR
607 && TREE_CODE (TREE_OPERAND (expr, 0)) == VAR_DECL
608 && TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == RECORD_TYPE)
609 return build1 (NOP_EXPR, type, expr);
611 /* Since expr is used twice below, save it. */
612 expr = save_expr (expr);
614 expr1 = build_headof (expr);
615 if (TREE_TYPE (expr1) != type)
616 expr1 = build1 (NOP_EXPR, type, expr1);
617 return ifnonnull (expr, expr1);
622 tree result, td2, td3;
624 tree static_type, target_type, boff;
626 /* If we got here, we can't convert statically. Therefore,
627 dynamic_cast<D&>(b) (b an object) cannot succeed. */
628 if (tc == REFERENCE_TYPE)
630 if (TREE_CODE (old_expr) == VAR_DECL
631 && TREE_CODE (TREE_TYPE (old_expr)) == RECORD_TYPE)
633 tree expr = throw_bad_cast ();
634 if (complain & tf_warning)
635 warning (0, "dynamic_cast of %q#D to %q#T can never succeed",
637 /* Bash it to the expected type. */
638 TREE_TYPE (expr) = type;
642 /* Ditto for dynamic_cast<D*>(&b). */
643 else if (TREE_CODE (expr) == ADDR_EXPR)
645 tree op = TREE_OPERAND (expr, 0);
646 if (TREE_CODE (op) == VAR_DECL
647 && TREE_CODE (TREE_TYPE (op)) == RECORD_TYPE)
649 if (complain & tf_warning)
650 warning (0, "dynamic_cast of %q#D to %q#T can never succeed",
652 retval = build_int_cst (type, 0);
657 /* Use of dynamic_cast when -fno-rtti is prohibited. */
660 if (complain & tf_error)
661 error ("%<dynamic_cast%> not permitted with -fno-rtti");
662 return error_mark_node;
665 target_type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
666 static_type = TYPE_MAIN_VARIANT (TREE_TYPE (exprtype));
667 td2 = get_tinfo_decl (target_type);
669 td2 = cp_build_unary_op (ADDR_EXPR, td2, 0, complain);
670 td3 = get_tinfo_decl (static_type);
672 td3 = cp_build_unary_op (ADDR_EXPR, td3, 0, complain);
674 /* Determine how T and V are related. */
675 boff = dcast_base_hint (static_type, target_type);
677 /* Since expr is used twice below, save it. */
678 expr = save_expr (expr);
681 if (tc == REFERENCE_TYPE)
682 expr1 = cp_build_unary_op (ADDR_EXPR, expr1, 0, complain);
689 dcast_fn = dynamic_cast_node;
696 push_abi_namespace ();
697 tinfo_ptr = xref_tag (class_type,
698 get_identifier ("__class_type_info"),
699 /*tag_scope=*/ts_current, false);
701 tinfo_ptr = build_pointer_type
702 (build_qualified_type
703 (tinfo_ptr, TYPE_QUAL_CONST));
704 name = "__dynamic_cast";
706 (NULL_TREE, const_ptr_type_node, tree_cons
707 (NULL_TREE, tinfo_ptr, tree_cons
708 (NULL_TREE, tinfo_ptr, tree_cons
709 (NULL_TREE, ptrdiff_type_node, void_list_node))));
710 tmp = build_function_type (ptr_type_node, tmp);
711 dcast_fn = build_library_fn_ptr (name, tmp);
712 DECL_PURE_P (dcast_fn) = 1;
713 pop_abi_namespace ();
714 dynamic_cast_node = dcast_fn;
716 result = build_cxx_call (dcast_fn, 4, elems);
718 if (tc == REFERENCE_TYPE)
720 tree bad = throw_bad_cast ();
723 result = save_expr (result);
724 neq = c_common_truthvalue_conversion (result);
725 return build3 (COND_EXPR, type, neq, result, bad);
728 /* Now back to the type we want from a void*. */
729 result = cp_convert (type, result);
730 return ifnonnull (expr, result);
734 errstr = "source type is not polymorphic";
737 if (complain & tf_error)
738 error ("cannot dynamic_cast %qE (of type %q#T) to type %q#T (%s)",
739 expr, exprtype, type, errstr);
740 return error_mark_node;
744 build_dynamic_cast (tree type, tree expr, tsubst_flags_t complain)
746 if (type == error_mark_node || expr == error_mark_node)
747 return error_mark_node;
749 if (processing_template_decl)
751 expr = build_min (DYNAMIC_CAST_EXPR, type, expr);
752 TREE_SIDE_EFFECTS (expr) = 1;
753 return convert_from_reference (expr);
756 return convert_from_reference (build_dynamic_cast_1 (type, expr, complain));
759 /* Return the runtime bit mask encoding the qualifiers of TYPE. */
762 qualifier_flags (tree type)
765 int quals = cp_type_quals (type);
767 if (quals & TYPE_QUAL_CONST)
769 if (quals & TYPE_QUAL_VOLATILE)
771 if (quals & TYPE_QUAL_RESTRICT)
776 /* Return true, if the pointer chain TYPE ends at an incomplete type, or
777 contains a pointer to member of an incomplete class. */
780 target_incomplete_p (tree type)
783 if (TYPE_PTRMEM_P (type))
785 if (!COMPLETE_TYPE_P (TYPE_PTRMEM_CLASS_TYPE (type)))
787 type = TYPE_PTRMEM_POINTED_TO_TYPE (type);
789 else if (TREE_CODE (type) == POINTER_TYPE)
790 type = TREE_TYPE (type);
792 return !COMPLETE_OR_VOID_TYPE_P (type);
795 /* Returns true if TYPE involves an incomplete class type; in that
796 case, typeinfo variables for TYPE should be emitted with internal
800 involves_incomplete_p (tree type)
802 switch (TREE_CODE (type))
805 return target_incomplete_p (TREE_TYPE (type));
810 (target_incomplete_p (TYPE_PTRMEM_POINTED_TO_TYPE (type))
811 || !COMPLETE_TYPE_P (TYPE_PTRMEM_CLASS_TYPE (type)));
814 if (TYPE_PTRMEMFUNC_P (type))
818 if (!COMPLETE_TYPE_P (type))
822 /* All other types do not involve incomplete class types. */
827 /* Return a CONSTRUCTOR for the common part of the type_info objects. This
828 is the vtable pointer and NTBS name. The NTBS name is emitted as a
829 comdat const char array, so it becomes a unique key for the type. Generate
830 and emit that VAR_DECL here. (We can't always emit the type_info itself
831 as comdat, because of pointers to incomplete.) */
834 tinfo_base_init (tinfo_s *ti, tree target)
836 tree init = NULL_TREE;
843 /* Generate the NTBS array variable. */
844 tree name_type = build_cplus_array_type
845 (build_qualified_type (char_type_node, TYPE_QUAL_CONST),
847 tree name_string = tinfo_name (target);
849 /* Determine the name of the variable -- and remember with which
850 type it is associated. */
851 name_name = mangle_typeinfo_string_for_type (target);
852 TREE_TYPE (name_name) = target;
854 name_decl = build_lang_decl (VAR_DECL, name_name, name_type);
855 SET_DECL_ASSEMBLER_NAME (name_decl, name_name);
856 DECL_ARTIFICIAL (name_decl) = 1;
857 DECL_IGNORED_P (name_decl) = 1;
858 TREE_READONLY (name_decl) = 1;
859 TREE_STATIC (name_decl) = 1;
860 DECL_EXTERNAL (name_decl) = 0;
861 DECL_TINFO_P (name_decl) = 1;
862 set_linkage_according_to_type (target, name_decl);
863 import_export_decl (name_decl);
864 DECL_INITIAL (name_decl) = name_string;
865 mark_used (name_decl);
866 pushdecl_top_level_and_finish (name_decl, name_string);
869 vtable_ptr = ti->vtable;
873 push_abi_namespace ();
874 real_type = xref_tag (class_type, ti->name,
875 /*tag_scope=*/ts_current, false);
876 pop_abi_namespace ();
878 if (!COMPLETE_TYPE_P (real_type))
880 /* We never saw a definition of this type, so we need to
881 tell the compiler that this is an exported class, as
882 indeed all of the __*_type_info classes are. */
883 SET_CLASSTYPE_INTERFACE_KNOWN (real_type);
884 CLASSTYPE_INTERFACE_ONLY (real_type) = 1;
887 vtable_ptr = get_vtable_decl (real_type, /*complete=*/1);
888 vtable_ptr = cp_build_unary_op (ADDR_EXPR, vtable_ptr, 0,
889 tf_warning_or_error);
891 /* We need to point into the middle of the vtable. */
893 (POINTER_PLUS_EXPR, TREE_TYPE (vtable_ptr), vtable_ptr,
894 size_binop (MULT_EXPR,
895 size_int (2 * TARGET_VTABLE_DATA_ENTRY_DISTANCE),
896 TYPE_SIZE_UNIT (vtable_entry_type)));
898 ti->vtable = vtable_ptr;
901 init = tree_cons (NULL_TREE, vtable_ptr, init);
903 init = tree_cons (NULL_TREE, decay_conversion (name_decl), init);
905 init = build_constructor_from_list (init_list_type_node, nreverse (init));
906 TREE_CONSTANT (init) = 1;
907 TREE_STATIC (init) = 1;
908 init = tree_cons (NULL_TREE, init, NULL_TREE);
913 /* Return the CONSTRUCTOR expr for a type_info of TYPE. TI provides the
914 information about the particular type_info derivation, which adds no
915 additional fields to the type_info base. */
918 generic_initializer (tinfo_s *ti, tree target)
920 tree init = tinfo_base_init (ti, target);
922 init = build_constructor_from_list (init_list_type_node, init);
923 TREE_CONSTANT (init) = 1;
924 TREE_STATIC (init) = 1;
928 /* Return the CONSTRUCTOR expr for a type_info of pointer TYPE.
929 TI provides information about the particular type_info derivation,
930 which adds target type and qualifier flags members to the type_info base. */
933 ptr_initializer (tinfo_s *ti, tree target)
935 tree init = tinfo_base_init (ti, target);
936 tree to = TREE_TYPE (target);
937 int flags = qualifier_flags (to);
938 bool incomplete = target_incomplete_p (to);
942 init = tree_cons (NULL_TREE, build_int_cst (NULL_TREE, flags), init);
943 init = tree_cons (NULL_TREE,
944 get_tinfo_ptr (TYPE_MAIN_VARIANT (to)),
947 init = build_constructor_from_list (init_list_type_node, nreverse (init));
948 TREE_CONSTANT (init) = 1;
949 TREE_STATIC (init) = 1;
953 /* Return the CONSTRUCTOR expr for a type_info of pointer to member data TYPE.
954 TI provides information about the particular type_info derivation,
955 which adds class, target type and qualifier flags members to the type_info
959 ptm_initializer (tinfo_s *ti, tree target)
961 tree init = tinfo_base_init (ti, target);
962 tree to = TYPE_PTRMEM_POINTED_TO_TYPE (target);
963 tree klass = TYPE_PTRMEM_CLASS_TYPE (target);
964 int flags = qualifier_flags (to);
965 bool incomplete = target_incomplete_p (to);
969 if (!COMPLETE_TYPE_P (klass))
971 init = tree_cons (NULL_TREE, build_int_cst (NULL_TREE, flags), init);
972 init = tree_cons (NULL_TREE,
973 get_tinfo_ptr (TYPE_MAIN_VARIANT (to)),
975 init = tree_cons (NULL_TREE,
976 get_tinfo_ptr (klass),
979 init = build_constructor_from_list (init_list_type_node, nreverse (init));
980 TREE_CONSTANT (init) = 1;
981 TREE_STATIC (init) = 1;
985 /* Return the CONSTRUCTOR expr for a type_info of class TYPE.
986 TI provides information about the particular __class_type_info derivation,
987 which adds hint flags and TRAIL initializers to the type_info base. */
990 class_initializer (tinfo_s *ti, tree target, tree trail)
992 tree init = tinfo_base_init (ti, target);
994 TREE_CHAIN (init) = trail;
995 init = build_constructor_from_list (init_list_type_node, init);
996 TREE_CONSTANT (init) = 1;
997 TREE_STATIC (init) = 1;
1001 /* Returns true if the typeinfo for type should be placed in
1002 the runtime library. */
1005 typeinfo_in_lib_p (tree type)
1007 /* The typeinfo objects for `T*' and `const T*' are in the runtime
1008 library for simple types T. */
1009 if (TREE_CODE (type) == POINTER_TYPE
1010 && (cp_type_quals (TREE_TYPE (type)) == TYPE_QUAL_CONST
1011 || cp_type_quals (TREE_TYPE (type)) == TYPE_UNQUALIFIED))
1012 type = TREE_TYPE (type);
1014 switch (TREE_CODE (type))
1027 /* Generate the initializer for the type info describing TYPE. TK_INDEX is
1028 the index of the descriptor in the tinfo_desc vector. */
1031 get_pseudo_ti_init (tree type, unsigned tk_index)
1033 tinfo_s *ti = VEC_index (tinfo_s, tinfo_descs, tk_index);
1035 gcc_assert (at_eof);
1038 case TK_POINTER_MEMBER_TYPE:
1039 return ptm_initializer (ti, type);
1041 case TK_POINTER_TYPE:
1042 return ptr_initializer (ti, type);
1044 case TK_BUILTIN_TYPE:
1045 case TK_ENUMERAL_TYPE:
1046 case TK_FUNCTION_TYPE:
1048 return generic_initializer (ti, type);
1051 return class_initializer (ti, type, NULL_TREE);
1053 case TK_SI_CLASS_TYPE:
1055 tree base_binfo = BINFO_BASE_BINFO (TYPE_BINFO (type), 0);
1056 tree tinfo = get_tinfo_ptr (BINFO_TYPE (base_binfo));
1057 tree base_inits = tree_cons (NULL_TREE, tinfo, NULL_TREE);
1059 /* get_tinfo_ptr might have reallocated the tinfo_descs vector. */
1060 ti = VEC_index (tinfo_s, tinfo_descs, tk_index);
1061 return class_initializer (ti, type, base_inits);
1066 int hint = ((CLASSTYPE_REPEATED_BASE_P (type) << 0)
1067 | (CLASSTYPE_DIAMOND_SHAPED_P (type) << 1));
1068 tree binfo = TYPE_BINFO (type);
1069 int nbases = BINFO_N_BASE_BINFOS (binfo);
1070 VEC(tree,gc) *base_accesses = BINFO_BASE_ACCESSES (binfo);
1071 tree offset_type = integer_types[itk_long];
1072 tree base_inits = NULL_TREE;
1075 gcc_assert (tk_index >= TK_FIXED);
1077 /* Generate the base information initializer. */
1078 for (ix = nbases; ix--;)
1080 tree base_binfo = BINFO_BASE_BINFO (binfo, ix);
1081 tree base_init = NULL_TREE;
1086 if (VEC_index (tree, base_accesses, ix) == access_public_node)
1088 tinfo = get_tinfo_ptr (BINFO_TYPE (base_binfo));
1089 if (BINFO_VIRTUAL_P (base_binfo))
1091 /* We store the vtable offset at which the virtual
1092 base offset can be found. */
1093 offset = BINFO_VPTR_FIELD (base_binfo);
1097 offset = BINFO_OFFSET (base_binfo);
1099 /* Combine offset and flags into one field. */
1100 offset = fold_convert (offset_type, offset);
1101 offset = fold_build2 (LSHIFT_EXPR, offset_type, offset,
1102 build_int_cst (offset_type, 8));
1103 offset = fold_build2 (BIT_IOR_EXPR, offset_type, offset,
1104 build_int_cst (offset_type, flags));
1105 base_init = tree_cons (NULL_TREE, offset, base_init);
1106 base_init = tree_cons (NULL_TREE, tinfo, base_init);
1107 base_init = build_constructor_from_list (init_list_type_node, base_init);
1108 base_inits = tree_cons (NULL_TREE, base_init, base_inits);
1110 base_inits = build_constructor_from_list (init_list_type_node, base_inits);
1111 base_inits = tree_cons (NULL_TREE, base_inits, NULL_TREE);
1112 /* Prepend the number of bases. */
1113 base_inits = tree_cons (NULL_TREE,
1114 build_int_cst (NULL_TREE, nbases),
1116 /* Prepend the hint flags. */
1117 base_inits = tree_cons (NULL_TREE,
1118 build_int_cst (NULL_TREE, hint),
1121 /* get_tinfo_ptr might have reallocated the tinfo_descs vector. */
1122 ti = VEC_index (tinfo_s, tinfo_descs, tk_index);
1123 return class_initializer (ti, type, base_inits);
1128 /* Generate the RECORD_TYPE containing the data layout of a type_info
1129 derivative as used by the runtime. This layout must be consistent with
1130 that defined in the runtime support. Also generate the VAR_DECL for the
1131 type's vtable. We explicitly manage the vtable member, and name it for
1132 real type as used in the runtime. The RECORD type has a different name,
1133 to avoid collisions. Return a TREE_LIST who's TINFO_PSEUDO_TYPE
1134 is the generated type and TINFO_VTABLE_NAME is the name of the
1135 vtable. We have to delay generating the VAR_DECL of the vtable
1136 until the end of the translation, when we'll have seen the library
1137 definition, if there was one.
1139 REAL_NAME is the runtime's name of the type. Trailing arguments are
1140 additional FIELD_DECL's for the structure. The final argument must be
1144 create_pseudo_type_info (int tk, const char *real_name, ...)
1153 va_start (ap, real_name);
1155 /* Generate the pseudo type name. */
1156 pseudo_name = (char *) alloca (strlen (real_name) + 30);
1157 strcpy (pseudo_name, real_name);
1158 strcat (pseudo_name, "_pseudo");
1160 sprintf (pseudo_name + strlen (pseudo_name), "%d", tk - TK_FIXED);
1162 /* First field is the pseudo type_info base class. */
1163 fields = build_decl (FIELD_DECL, NULL_TREE,
1164 VEC_index (tinfo_s, tinfo_descs,
1165 TK_TYPE_INFO_TYPE)->type);
1167 /* Now add the derived fields. */
1168 while ((field_decl = va_arg (ap, tree)))
1170 TREE_CHAIN (field_decl) = fields;
1171 fields = field_decl;
1174 /* Create the pseudo type. */
1175 pseudo_type = make_class_type (RECORD_TYPE);
1176 finish_builtin_struct (pseudo_type, pseudo_name, fields, NULL_TREE);
1177 CLASSTYPE_AS_BASE (pseudo_type) = pseudo_type;
1179 ti = VEC_index (tinfo_s, tinfo_descs, tk);
1180 ti->type = cp_build_qualified_type (pseudo_type, TYPE_QUAL_CONST);
1181 ti->name = get_identifier (real_name);
1182 ti->vtable = NULL_TREE;
1184 /* Pretend this is public so determine_visibility doesn't give vtables
1185 internal linkage. */
1186 TREE_PUBLIC (TYPE_MAIN_DECL (ti->type)) = 1;
1191 /* Return the index of a pseudo type info type node used to describe
1192 TYPE. TYPE must be a complete type (or cv void), except at the end
1193 of the translation unit. */
1196 get_pseudo_ti_index (tree type)
1200 switch (TREE_CODE (type))
1203 ix = TK_POINTER_MEMBER_TYPE;
1207 ix = TK_POINTER_TYPE;
1211 ix = TK_ENUMERAL_TYPE;
1215 ix = TK_FUNCTION_TYPE;
1224 if (TYPE_PTRMEMFUNC_P (type))
1226 ix = TK_POINTER_MEMBER_TYPE;
1229 else if (!COMPLETE_TYPE_P (type))
1232 cxx_incomplete_type_error (NULL_TREE, type);
1236 else if (!BINFO_N_BASE_BINFOS (TYPE_BINFO (type)))
1243 tree binfo = TYPE_BINFO (type);
1244 VEC(tree,gc) *base_accesses = BINFO_BASE_ACCESSES (binfo);
1245 tree base_binfo = BINFO_BASE_BINFO (binfo, 0);
1246 int num_bases = BINFO_N_BASE_BINFOS (binfo);
1249 && VEC_index (tree, base_accesses, 0) == access_public_node
1250 && !BINFO_VIRTUAL_P (base_binfo)
1251 && integer_zerop (BINFO_OFFSET (base_binfo)))
1253 /* single non-virtual public. */
1254 ix = TK_SI_CLASS_TYPE;
1260 tree array_domain, base_array;
1262 ix = TK_FIXED + num_bases;
1263 if (VEC_length (tinfo_s, tinfo_descs) <= ix)
1265 /* too short, extend. */
1266 unsigned len = VEC_length (tinfo_s, tinfo_descs);
1268 VEC_safe_grow (tinfo_s, gc, tinfo_descs, ix + 1);
1269 while (VEC_iterate (tinfo_s, tinfo_descs, len++, ti))
1270 ti->type = ti->vtable = ti->name = NULL_TREE;
1272 else if (VEC_index (tinfo_s, tinfo_descs, ix)->type)
1273 /* already created. */
1276 /* Create the array of __base_class_type_info entries.
1277 G++ 3.2 allocated an array that had one too many
1278 entries, and then filled that extra entries with
1280 if (abi_version_at_least (2))
1281 array_domain = build_index_type (size_int (num_bases - 1));
1283 array_domain = build_index_type (size_int (num_bases));
1285 build_array_type (VEC_index (tinfo_s, tinfo_descs,
1286 TK_BASE_TYPE)->type,
1289 push_abi_namespace ();
1290 create_pseudo_type_info
1291 (ix, "__vmi_class_type_info",
1292 build_decl (FIELD_DECL, NULL_TREE, integer_type_node),
1293 build_decl (FIELD_DECL, NULL_TREE, integer_type_node),
1294 build_decl (FIELD_DECL, NULL_TREE, base_array),
1296 pop_abi_namespace ();
1301 ix = TK_BUILTIN_TYPE;
1307 /* Make sure the required builtin types exist for generating the type_info
1308 variable definitions. */
1311 create_tinfo_types (void)
1315 gcc_assert (!tinfo_descs);
1317 VEC_safe_grow (tinfo_s, gc, tinfo_descs, TK_FIXED);
1319 push_abi_namespace ();
1321 /* Create the internal type_info structure. This is used as a base for
1322 the other structures. */
1326 field = build_decl (FIELD_DECL, NULL_TREE, const_ptr_type_node);
1329 field = build_decl (FIELD_DECL, NULL_TREE, const_string_type_node);
1330 TREE_CHAIN (field) = fields;
1333 ti = VEC_index (tinfo_s, tinfo_descs, TK_TYPE_INFO_TYPE);
1334 ti->type = make_class_type (RECORD_TYPE);
1335 ti->vtable = NULL_TREE;
1336 ti->name = NULL_TREE;
1337 finish_builtin_struct (ti->type, "__type_info_pseudo",
1341 /* Fundamental type_info */
1342 create_pseudo_type_info (TK_BUILTIN_TYPE, "__fundamental_type_info", NULL);
1344 /* Array, function and enum type_info. No additional fields. */
1345 create_pseudo_type_info (TK_ARRAY_TYPE, "__array_type_info", NULL);
1346 create_pseudo_type_info (TK_FUNCTION_TYPE, "__function_type_info", NULL);
1347 create_pseudo_type_info (TK_ENUMERAL_TYPE, "__enum_type_info", NULL);
1349 /* Class type_info. No additional fields. */
1350 create_pseudo_type_info (TK_CLASS_TYPE, "__class_type_info", NULL);
1352 /* Single public non-virtual base class. Add pointer to base class.
1353 This is really a descendant of __class_type_info. */
1354 create_pseudo_type_info (TK_SI_CLASS_TYPE, "__si_class_type_info",
1355 build_decl (FIELD_DECL, NULL_TREE, type_info_ptr_type),
1358 /* Base class internal helper. Pointer to base type, offset to base,
1363 field = build_decl (FIELD_DECL, NULL_TREE, type_info_ptr_type);
1366 field = build_decl (FIELD_DECL, NULL_TREE, integer_types[itk_long]);
1367 TREE_CHAIN (field) = fields;
1370 ti = VEC_index (tinfo_s, tinfo_descs, TK_BASE_TYPE);
1372 ti->type = make_class_type (RECORD_TYPE);
1373 ti->vtable = NULL_TREE;
1374 ti->name = NULL_TREE;
1375 finish_builtin_struct (ti->type, "__base_class_type_info_pseudo",
1379 /* Pointer type_info. Adds two fields, qualification mask
1380 and pointer to the pointed to type. This is really a descendant of
1381 __pbase_type_info. */
1382 create_pseudo_type_info (TK_POINTER_TYPE, "__pointer_type_info",
1383 build_decl (FIELD_DECL, NULL_TREE, integer_type_node),
1384 build_decl (FIELD_DECL, NULL_TREE, type_info_ptr_type),
1387 /* Pointer to member data type_info. Add qualifications flags,
1388 pointer to the member's type info and pointer to the class.
1389 This is really a descendant of __pbase_type_info. */
1390 create_pseudo_type_info (TK_POINTER_MEMBER_TYPE,
1391 "__pointer_to_member_type_info",
1392 build_decl (FIELD_DECL, NULL_TREE, integer_type_node),
1393 build_decl (FIELD_DECL, NULL_TREE, type_info_ptr_type),
1394 build_decl (FIELD_DECL, NULL_TREE, type_info_ptr_type),
1397 pop_abi_namespace ();
1400 /* Emit the type_info descriptors which are guaranteed to be in the runtime
1401 support. Generating them here guarantees consistency with the other
1402 structures. We use the following heuristic to determine when the runtime
1403 is being generated. If std::__fundamental_type_info is defined, and its
1404 destructor is defined, then the runtime is being built. */
1407 emit_support_tinfos (void)
1409 static tree *const fundamentals[] =
1413 &wchar_type_node, &char16_type_node, &char32_type_node,
1414 &char_type_node, &signed_char_type_node, &unsigned_char_type_node,
1415 &short_integer_type_node, &short_unsigned_type_node,
1416 &integer_type_node, &unsigned_type_node,
1417 &long_integer_type_node, &long_unsigned_type_node,
1418 &long_long_integer_type_node, &long_long_unsigned_type_node,
1419 &float_type_node, &double_type_node, &long_double_type_node,
1423 tree bltn_type, dtor;
1425 push_abi_namespace ();
1426 bltn_type = xref_tag (class_type,
1427 get_identifier ("__fundamental_type_info"),
1428 /*tag_scope=*/ts_current, false);
1429 pop_abi_namespace ();
1430 if (!COMPLETE_TYPE_P (bltn_type))
1432 dtor = CLASSTYPE_DESTRUCTORS (bltn_type);
1433 if (!dtor || DECL_EXTERNAL (dtor))
1436 for (ix = 0; fundamentals[ix]; ix++)
1438 tree bltn = *fundamentals[ix];
1443 types[1] = build_pointer_type (bltn);
1444 types[2] = build_pointer_type (build_qualified_type (bltn,
1447 for (i = 0; i < 3; ++i)
1451 tinfo = get_tinfo_decl (types[i]);
1452 TREE_USED (tinfo) = 1;
1453 mark_needed (tinfo);
1454 /* The C++ ABI requires that these objects be COMDAT. But,
1455 On systems without weak symbols, initialized COMDAT
1456 objects are emitted with internal linkage. (See
1457 comdat_linkage for details.) Since we want these objects
1458 to have external linkage so that copies do not have to be
1459 emitted in code outside the runtime library, we make them
1462 It might also not be necessary to follow this detail of the
1464 if (!flag_weak || ! targetm.cxx.library_rtti_comdat ())
1466 gcc_assert (TREE_PUBLIC (tinfo) && !DECL_COMDAT (tinfo));
1467 DECL_INTERFACE_KNOWN (tinfo) = 1;
1473 /* Finish a type info decl. DECL_PTR is a pointer to an unemitted
1474 tinfo decl. Determine whether it needs emitting, and if so
1475 generate the initializer. */
1478 emit_tinfo_decl (tree decl)
1480 tree type = TREE_TYPE (DECL_NAME (decl));
1481 int in_library = typeinfo_in_lib_p (type);
1483 gcc_assert (DECL_TINFO_P (decl));
1488 DECL_EXTERNAL (decl) = 0;
1491 /* If we're not in the runtime, then DECL (which is already
1492 DECL_EXTERNAL) will not be defined here. */
1493 DECL_INTERFACE_KNOWN (decl) = 1;
1497 else if (involves_incomplete_p (type))
1499 if (!decl_needed_p (decl))
1501 /* If TYPE involves an incomplete class type, then the typeinfo
1502 object will be emitted with internal linkage. There is no
1503 way to know whether or not types are incomplete until the end
1504 of the compilation, so this determination must be deferred
1505 until this point. */
1506 TREE_PUBLIC (decl) = 0;
1507 DECL_EXTERNAL (decl) = 0;
1508 DECL_INTERFACE_KNOWN (decl) = 1;
1511 import_export_decl (decl);
1512 if (DECL_NOT_REALLY_EXTERN (decl) && decl_needed_p (decl))
1516 DECL_EXTERNAL (decl) = 0;
1517 init = get_pseudo_ti_init (type, get_pseudo_ti_index (type));
1518 DECL_INITIAL (decl) = init;
1520 finish_decl (decl, init, NULL_TREE);
1527 #include "gt-cp-rtti.h"