1 // RTTI support for -*- C++ -*-
2 // Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
3 // 2003, 2004, 2005, 2006, 2007, 2009, 2010
4 // Free Software Foundation
6 // This file is part of GCC.
8 // GCC is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3, or (at your option)
13 // GCC is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // Under Section 7 of GPL version 3, you are granted additional
19 // permissions described in the GCC Runtime Library Exception, version
20 // 3.1, as published by the Free Software Foundation.
22 // You should have received a copy of the GNU General Public License and
23 // a copy of the GCC Runtime Library Exception along with this program;
24 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 // <http://www.gnu.org/licenses/>.
28 * This is a Standard C++ Library header.
34 #pragma GCC system_header
38 #pragma GCC visibility push(default)
44 class __class_type_info;
45 } // namespace __cxxabiv1
47 // Determine whether typeinfo names for the same type are merged (in which
48 // case comparison can just compare pointers) or not (in which case strings
49 // must be compared), and whether comparison is to be implemented inline or
50 // not. We used to do inline pointer comparison by default if weak symbols
51 // are available, but even with weak symbols sometimes names are not merged
52 // when objects are loaded with RTLD_LOCAL, so now we always use strcmp by
53 // default. For ABI compatibility, we do the strcmp inline if weak symbols
54 // are available, and out-of-line if not. Out-of-line pointer comparison
55 // is used where the object files are to be portable to multiple systems,
56 // some of which may not be able to use pointer comparison, but the
57 // particular system for which libstdc++ is being built can use pointer
58 // comparison; in particular for most ARM EABI systems, where the ABI
59 // specifies out-of-line comparison. The compiler's target configuration
60 // can override the defaults by defining __GXX_TYPEINFO_EQUALITY_INLINE to
61 // 1 or 0 to indicate whether or not comparison is inline, and
62 // __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to indicate whether or not pointer
63 // comparison can be used.
65 #ifndef __GXX_MERGED_TYPEINFO_NAMES
66 // By default, typeinfo names are not merged.
67 #define __GXX_MERGED_TYPEINFO_NAMES 0
70 // By default follow the old inline rules to avoid ABI changes.
71 #ifndef __GXX_TYPEINFO_EQUALITY_INLINE
73 #define __GXX_TYPEINFO_EQUALITY_INLINE 0
75 #define __GXX_TYPEINFO_EQUALITY_INLINE 1
82 * @brief Part of RTTI.
84 * The @c type_info class describes type information generated by
90 /** Destructor first. Being the first non-inline virtual function, this
91 * controls in which translation unit the vtable is emitted. The
92 * compiler makes use of that information to know where to emit
93 * the runtime-mandated type_info structures in the new-abi. */
96 /** Returns an @e implementation-defined byte string; this is not
97 * portable between compilers! */
98 const char* name() const
99 { return __name[0] == '*' ? __name + 1 : __name; }
101 #if !__GXX_TYPEINFO_EQUALITY_INLINE
102 // In old abi, or when weak symbols are not supported, there can
103 // be multiple instances of a type_info object for one
104 // type. Uniqueness must use the _name value, not object address.
105 bool before(const type_info& __arg) const;
106 bool operator==(const type_info& __arg) const;
108 #if !__GXX_MERGED_TYPEINFO_NAMES
109 /** Returns true if @c *this precedes @c __arg in the implementation's
110 * collation order. */
111 // Even with the new abi, on systems that support dlopen
112 // we can run into cases where type_info names aren't merged,
113 // so we still need to do string comparison.
114 bool before(const type_info& __arg) const
115 { return (__name[0] == '*' && __arg.__name[0] == '*')
116 ? __name < __arg.__name
117 : __builtin_strcmp (__name, __arg.__name) < 0; }
119 bool operator==(const type_info& __arg) const
121 return ((__name == __arg.__name)
122 || (__name[0] != '*' &&
123 __builtin_strcmp (__name, __arg.__name) == 0));
126 // On some targets we can rely on type_info's NTBS being unique,
127 // and therefore address comparisons are sufficient.
128 bool before(const type_info& __arg) const
129 { return __name < __arg.__name; }
131 bool operator==(const type_info& __arg) const
132 { return __name == __arg.__name; }
135 bool operator!=(const type_info& __arg) const
136 { return !operator==(__arg); }
138 // Return true if this is a pointer type of some kind
139 virtual bool __is_pointer_p() const;
141 // Return true if this is a function type
142 virtual bool __is_function_p() const;
144 // Try and catch a thrown type. Store an adjusted pointer to the
145 // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
146 // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
147 // type, then THR_OBJ is the pointer itself. OUTER indicates the
148 // number of outer pointers, and whether they were const
150 virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
151 unsigned __outer) const;
153 // Internally used during catch matching
154 virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
155 void **__obj_ptr) const;
160 explicit type_info(const char *__n): __name(__n) { }
163 /// Assigning type_info is not supported.
164 type_info& operator=(const type_info&);
165 type_info(const type_info&);
169 * @brief Thrown during incorrect typecasting.
170 * @ingroup exceptions
172 * If you attempt an invalid @c dynamic_cast expression, an instance of
173 * this class (or something derived from this class) is thrown. */
174 class bad_cast : public exception
177 bad_cast() throw() { }
179 // This declaration is not useless:
180 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
181 virtual ~bad_cast() throw();
183 // See comment in eh_exception.cc.
184 virtual const char* what() const throw();
188 * @brief Thrown when a NULL pointer in a @c typeid expression is used.
189 * @ingroup exceptions
191 class bad_typeid : public exception
194 bad_typeid () throw() { }
196 // This declaration is not useless:
197 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
198 virtual ~bad_typeid() throw();
200 // See comment in eh_exception.cc.
201 virtual const char* what() const throw();
205 #pragma GCC visibility pop