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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, 2012
4 : : // Free Software Foundation
5 : : //
6 : : // This file is part of GCC.
7 : : //
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)
11 : : // any later version.
12 : : //
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.
17 : : //
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.
21 : :
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/>.
26 : :
27 : : /** @file typeinfo
28 : : * This is a Standard C++ Library header.
29 : : */
30 : :
31 : : #ifndef _TYPEINFO
32 : : #define _TYPEINFO
33 : :
34 : : #pragma GCC system_header
35 : :
36 : : #include <exception>
37 : : #ifdef __GXX_EXPERIMENTAL_CXX0X__
38 : : #include <bits/hash_bytes.h>
39 : : #endif
40 : :
41 : : #pragma GCC visibility push(default)
42 : :
43 : : extern "C++" {
44 : :
45 : : namespace __cxxabiv1
46 : : {
47 : : class __class_type_info;
48 : : } // namespace __cxxabiv1
49 : :
50 : : // Determine whether typeinfo names for the same type are merged (in which
51 : : // case comparison can just compare pointers) or not (in which case strings
52 : : // must be compared), and whether comparison is to be implemented inline or
53 : : // not. We used to do inline pointer comparison by default if weak symbols
54 : : // are available, but even with weak symbols sometimes names are not merged
55 : : // when objects are loaded with RTLD_LOCAL, so now we always use strcmp by
56 : : // default. For ABI compatibility, we do the strcmp inline if weak symbols
57 : : // are available, and out-of-line if not. Out-of-line pointer comparison
58 : : // is used where the object files are to be portable to multiple systems,
59 : : // some of which may not be able to use pointer comparison, but the
60 : : // particular system for which libstdc++ is being built can use pointer
61 : : // comparison; in particular for most ARM EABI systems, where the ABI
62 : : // specifies out-of-line comparison. The compiler's target configuration
63 : : // can override the defaults by defining __GXX_TYPEINFO_EQUALITY_INLINE to
64 : : // 1 or 0 to indicate whether or not comparison is inline, and
65 : : // __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to indicate whether or not pointer
66 : : // comparison can be used.
67 : :
68 : : #ifndef __GXX_MERGED_TYPEINFO_NAMES
69 : : // By default, typeinfo names are not merged.
70 : : #define __GXX_MERGED_TYPEINFO_NAMES 0
71 : : #endif
72 : :
73 : : // By default follow the old inline rules to avoid ABI changes.
74 : : #ifndef __GXX_TYPEINFO_EQUALITY_INLINE
75 : : #if !__GXX_WEAK__
76 : : #define __GXX_TYPEINFO_EQUALITY_INLINE 0
77 : : #else
78 : : #define __GXX_TYPEINFO_EQUALITY_INLINE 1
79 : : #endif
80 : : #endif
81 : :
82 : : namespace std
83 : : {
84 : : /**
85 : : * @brief Part of RTTI.
86 : : *
87 : : * The @c type_info class describes type information generated by
88 : : * an implementation.
89 : : */
90 : : class type_info
91 : : {
92 : : public:
93 : : /** Destructor first. Being the first non-inline virtual function, this
94 : : * controls in which translation unit the vtable is emitted. The
95 : : * compiler makes use of that information to know where to emit
96 : : * the runtime-mandated type_info structures in the new-abi. */
97 : : virtual ~type_info();
98 : :
99 : : /** Returns an @e implementation-defined byte string; this is not
100 : : * portable between compilers! */
101 : 0 : const char* name() const
102 [ # # ]: 0 : { return __name[0] == '*' ? __name + 1 : __name; }
103 : :
104 : : #if !__GXX_TYPEINFO_EQUALITY_INLINE
105 : : // In old abi, or when weak symbols are not supported, there can
106 : : // be multiple instances of a type_info object for one
107 : : // type. Uniqueness must use the _name value, not object address.
108 : : bool before(const type_info& __arg) const;
109 : : bool operator==(const type_info& __arg) const;
110 : : #else
111 : : #if !__GXX_MERGED_TYPEINFO_NAMES
112 : : /** Returns true if @c *this precedes @c __arg in the implementation's
113 : : * collation order. */
114 : : // Even with the new abi, on systems that support dlopen
115 : : // we can run into cases where type_info names aren't merged,
116 : : // so we still need to do string comparison.
117 : : bool before(const type_info& __arg) const
118 : : { return (__name[0] == '*' && __arg.__name[0] == '*')
119 : : ? __name < __arg.__name
120 : : : __builtin_strcmp (__name, __arg.__name) < 0; }
121 : :
122 : : bool operator==(const type_info& __arg) const
123 : : {
124 : : return ((__name == __arg.__name)
125 : : || (__name[0] != '*' &&
126 : : __builtin_strcmp (__name, __arg.__name) == 0));
127 : : }
128 : : #else
129 : : // On some targets we can rely on type_info's NTBS being unique,
130 : : // and therefore address comparisons are sufficient.
131 : : bool before(const type_info& __arg) const
132 : : { return __name < __arg.__name; }
133 : :
134 : : bool operator==(const type_info& __arg) const
135 : : { return __name == __arg.__name; }
136 : : #endif
137 : : #endif
138 : : bool operator!=(const type_info& __arg) const
139 : : { return !operator==(__arg); }
140 : :
141 : : #ifdef __GXX_EXPERIMENTAL_CXX0X__
142 : : size_t hash_code() const noexcept
143 : : {
144 : : # if !__GXX_MERGED_TYPEINFO_NAMES
145 : : return _Hash_bytes(name(), __builtin_strlen(name()),
146 : : static_cast<size_t>(0xc70f6907UL));
147 : : # else
148 : : return reinterpret_cast<size_t>(__name);
149 : : # endif
150 : : }
151 : : #endif // __GXX_EXPERIMENTAL_CXX0X__
152 : :
153 : : // Return true if this is a pointer type of some kind
154 : : virtual bool __is_pointer_p() const;
155 : :
156 : : // Return true if this is a function type
157 : : virtual bool __is_function_p() const;
158 : :
159 : : // Try and catch a thrown type. Store an adjusted pointer to the
160 : : // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
161 : : // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
162 : : // type, then THR_OBJ is the pointer itself. OUTER indicates the
163 : : // number of outer pointers, and whether they were const
164 : : // qualified.
165 : : virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
166 : : unsigned __outer) const;
167 : :
168 : : // Internally used during catch matching
169 : : virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
170 : : void **__obj_ptr) const;
171 : :
172 : : protected:
173 : : const char *__name;
174 : :
175 : : explicit type_info(const char *__n): __name(__n) { }
176 : :
177 : : private:
178 : : /// Assigning type_info is not supported.
179 : : type_info& operator=(const type_info&);
180 : : type_info(const type_info&);
181 : : };
182 : :
183 : : /**
184 : : * @brief Thrown during incorrect typecasting.
185 : : * @ingroup exceptions
186 : : *
187 : : * If you attempt an invalid @c dynamic_cast expression, an instance of
188 : : * this class (or something derived from this class) is thrown. */
189 : : class bad_cast : public exception
190 : : {
191 : : public:
192 : : bad_cast() _GLIBCXX_USE_NOEXCEPT { }
193 : :
194 : : // This declaration is not useless:
195 : : // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
196 : : virtual ~bad_cast() _GLIBCXX_USE_NOEXCEPT;
197 : :
198 : : // See comment in eh_exception.cc.
199 : : virtual const char* what() const _GLIBCXX_USE_NOEXCEPT;
200 : : };
201 : :
202 : : /**
203 : : * @brief Thrown when a NULL pointer in a @c typeid expression is used.
204 : : * @ingroup exceptions
205 : : */
206 : : class bad_typeid : public exception
207 : : {
208 : : public:
209 : : bad_typeid () _GLIBCXX_USE_NOEXCEPT { }
210 : :
211 : : // This declaration is not useless:
212 : : // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
213 : : virtual ~bad_typeid() _GLIBCXX_USE_NOEXCEPT;
214 : :
215 : : // See comment in eh_exception.cc.
216 : : virtual const char* what() const _GLIBCXX_USE_NOEXCEPT;
217 : : };
218 : : } // namespace std
219 : :
220 : : } // extern "C++"
221 : :
222 : : #pragma GCC visibility pop
223 : :
224 : : #endif
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