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, 2011
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
37 #ifdef __GXX_EXPERIMENTAL_CXX0X__
38 #include <bits/hash_bytes.h>
42 #pragma GCC visibility push(default)
48 class __class_type_info;
49 } // namespace __cxxabiv1
51 // Determine whether typeinfo names for the same type are merged (in which
52 // case comparison can just compare pointers) or not (in which case strings
53 // must be compared), and whether comparison is to be implemented inline or
54 // not. We used to do inline pointer comparison by default if weak symbols
55 // are available, but even with weak symbols sometimes names are not merged
56 // when objects are loaded with RTLD_LOCAL, so now we always use strcmp by
57 // default. For ABI compatibility, we do the strcmp inline if weak symbols
58 // are available, and out-of-line if not. Out-of-line pointer comparison
59 // is used where the object files are to be portable to multiple systems,
60 // some of which may not be able to use pointer comparison, but the
61 // particular system for which libstdc++ is being built can use pointer
62 // comparison; in particular for most ARM EABI systems, where the ABI
63 // specifies out-of-line comparison. The compiler's target configuration
64 // can override the defaults by defining __GXX_TYPEINFO_EQUALITY_INLINE to
65 // 1 or 0 to indicate whether or not comparison is inline, and
66 // __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to indicate whether or not pointer
67 // comparison can be used.
69 #ifndef __GXX_MERGED_TYPEINFO_NAMES
70 // By default, typeinfo names are not merged.
71 #define __GXX_MERGED_TYPEINFO_NAMES 0
74 // By default follow the old inline rules to avoid ABI changes.
75 #ifndef __GXX_TYPEINFO_EQUALITY_INLINE
77 #define __GXX_TYPEINFO_EQUALITY_INLINE 0
79 #define __GXX_TYPEINFO_EQUALITY_INLINE 1
86 * @brief Part of RTTI.
88 * The @c type_info class describes type information generated by
94 /** Destructor first. Being the first non-inline virtual function, this
95 * controls in which translation unit the vtable is emitted. The
96 * compiler makes use of that information to know where to emit
97 * the runtime-mandated type_info structures in the new-abi. */
100 /** Returns an @e implementation-defined byte string; this is not
101 * portable between compilers! */
102 const char* name() const
103 { return __name[0] == '*' ? __name + 1 : __name; }
105 #if !__GXX_TYPEINFO_EQUALITY_INLINE
106 // In old abi, or when weak symbols are not supported, there can
107 // be multiple instances of a type_info object for one
108 // type. Uniqueness must use the _name value, not object address.
109 bool before(const type_info& __arg) const;
110 bool operator==(const type_info& __arg) const;
112 #if !__GXX_MERGED_TYPEINFO_NAMES
113 /** Returns true if @c *this precedes @c __arg in the implementation's
114 * collation order. */
115 // Even with the new abi, on systems that support dlopen
116 // we can run into cases where type_info names aren't merged,
117 // so we still need to do string comparison.
118 bool before(const type_info& __arg) const
119 { return (__name[0] == '*' && __arg.__name[0] == '*')
120 ? __name < __arg.__name
121 : __builtin_strcmp (__name, __arg.__name) < 0; }
123 bool operator==(const type_info& __arg) const
125 return ((__name == __arg.__name)
126 || (__name[0] != '*' &&
127 __builtin_strcmp (__name, __arg.__name) == 0));
130 // On some targets we can rely on type_info's NTBS being unique,
131 // and therefore address comparisons are sufficient.
132 bool before(const type_info& __arg) const
133 { return __name < __arg.__name; }
135 bool operator==(const type_info& __arg) const
136 { return __name == __arg.__name; }
139 bool operator!=(const type_info& __arg) const
140 { return !operator==(__arg); }
142 #ifdef __GXX_EXPERIMENTAL_CXX0X__
143 size_t hash_code() const throw()
145 # if !__GXX_MERGED_TYPEINFO_NAMES
146 return _Hash_bytes(name(), __builtin_strlen(name()),
147 static_cast<size_t>(0xc70f6907UL));
149 return reinterpret_cast<size_t>(__name);
152 #endif // __GXX_EXPERIMENTAL_CXX0X__
154 // Return true if this is a pointer type of some kind
155 virtual bool __is_pointer_p() const;
157 // Return true if this is a function type
158 virtual bool __is_function_p() const;
160 // Try and catch a thrown type. Store an adjusted pointer to the
161 // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
162 // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
163 // type, then THR_OBJ is the pointer itself. OUTER indicates the
164 // number of outer pointers, and whether they were const
166 virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
167 unsigned __outer) const;
169 // Internally used during catch matching
170 virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
171 void **__obj_ptr) const;
176 explicit type_info(const char *__n): __name(__n) { }
179 /// Assigning type_info is not supported.
180 type_info& operator=(const type_info&);
181 type_info(const type_info&);
185 * @brief Thrown during incorrect typecasting.
186 * @ingroup exceptions
188 * If you attempt an invalid @c dynamic_cast expression, an instance of
189 * this class (or something derived from this class) is thrown. */
190 class bad_cast : public exception
193 bad_cast() throw() { }
195 // This declaration is not useless:
196 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
197 virtual ~bad_cast() throw();
199 // See comment in eh_exception.cc.
200 virtual const char* what() const throw();
204 * @brief Thrown when a NULL pointer in a @c typeid expression is used.
205 * @ingroup exceptions
207 class bad_typeid : public exception
210 bad_typeid () throw() { }
212 // This declaration is not useless:
213 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
214 virtual ~bad_typeid() throw();
216 // See comment in eh_exception.cc.
217 virtual const char* what() const throw();
221 #pragma GCC visibility pop