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1 : : // RTTI support for -*- C++ -*-
2 : : // Copyright (C) 1994-2013 Free Software Foundation, Inc.
3 : : //
4 : : // This file is part of GCC.
5 : : //
6 : : // GCC is free software; you can redistribute it and/or modify
7 : : // it under the terms of the GNU General Public License as published by
8 : : // the Free Software Foundation; either version 3, or (at your option)
9 : : // any later version.
10 : : //
11 : : // GCC is distributed in the hope that it will be useful,
12 : : // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 : : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 : : // GNU General Public License for more details.
15 : : //
16 : : // Under Section 7 of GPL version 3, you are granted additional
17 : : // permissions described in the GCC Runtime Library Exception, version
18 : : // 3.1, as published by the Free Software Foundation.
19 : :
20 : : // You should have received a copy of the GNU General Public License and
21 : : // a copy of the GCC Runtime Library Exception along with this program;
22 : : // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 : : // <http://www.gnu.org/licenses/>.
24 : :
25 : : /** @file typeinfo
26 : : * This is a Standard C++ Library header.
27 : : */
28 : :
29 : : #ifndef _TYPEINFO
30 : : #define _TYPEINFO
31 : :
32 : : #pragma GCC system_header
33 : :
34 : : #include <exception>
35 : : #if __cplusplus >= 201103L
36 : : #include <bits/hash_bytes.h>
37 : : #endif
38 : :
39 : : #pragma GCC visibility push(default)
40 : :
41 : : extern "C++" {
42 : :
43 : : namespace __cxxabiv1
44 : : {
45 : : class __class_type_info;
46 : : } // namespace __cxxabiv1
47 : :
48 : : // Determine whether typeinfo names for the same type are merged (in which
49 : : // case comparison can just compare pointers) or not (in which case strings
50 : : // must be compared), and whether comparison is to be implemented inline or
51 : : // not. We used to do inline pointer comparison by default if weak symbols
52 : : // are available, but even with weak symbols sometimes names are not merged
53 : : // when objects are loaded with RTLD_LOCAL, so now we always use strcmp by
54 : : // default. For ABI compatibility, we do the strcmp inline if weak symbols
55 : : // are available, and out-of-line if not. Out-of-line pointer comparison
56 : : // is used where the object files are to be portable to multiple systems,
57 : : // some of which may not be able to use pointer comparison, but the
58 : : // particular system for which libstdc++ is being built can use pointer
59 : : // comparison; in particular for most ARM EABI systems, where the ABI
60 : : // specifies out-of-line comparison. The compiler's target configuration
61 : : // can override the defaults by defining __GXX_TYPEINFO_EQUALITY_INLINE to
62 : : // 1 or 0 to indicate whether or not comparison is inline, and
63 : : // __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to indicate whether or not pointer
64 : : // comparison can be used.
65 : :
66 : : #ifndef __GXX_MERGED_TYPEINFO_NAMES
67 : : // By default, typeinfo names are not merged.
68 : : #define __GXX_MERGED_TYPEINFO_NAMES 0
69 : : #endif
70 : :
71 : : // By default follow the old inline rules to avoid ABI changes.
72 : : #ifndef __GXX_TYPEINFO_EQUALITY_INLINE
73 : : #if !__GXX_WEAK__
74 : : #define __GXX_TYPEINFO_EQUALITY_INLINE 0
75 : : #else
76 : : #define __GXX_TYPEINFO_EQUALITY_INLINE 1
77 : : #endif
78 : : #endif
79 : :
80 : : namespace std
81 : : {
82 : : /**
83 : : * @brief Part of RTTI.
84 : : *
85 : : * The @c type_info class describes type information generated by
86 : : * an implementation.
87 : : */
88 : : class type_info
89 : : {
90 : : public:
91 : : /** Destructor first. Being the first non-inline virtual function, this
92 : : * controls in which translation unit the vtable is emitted. The
93 : : * compiler makes use of that information to know where to emit
94 : : * the runtime-mandated type_info structures in the new-abi. */
95 : : virtual ~type_info();
96 : :
97 : : /** Returns an @e implementation-defined byte string; this is not
98 : : * portable between compilers! */
99 : 221 : const char* name() const _GLIBCXX_NOEXCEPT
100 [ - + ]: 221 : { return __name[0] == '*' ? __name + 1 : __name; }
101 : :
102 : : #if !__GXX_TYPEINFO_EQUALITY_INLINE
103 : : // In old abi, or when weak symbols are not supported, there can
104 : : // be multiple instances of a type_info object for one
105 : : // type. Uniqueness must use the _name value, not object address.
106 : : bool before(const type_info& __arg) const _GLIBCXX_NOEXCEPT;
107 : : bool operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT;
108 : : #else
109 : : #if !__GXX_MERGED_TYPEINFO_NAMES
110 : : /** Returns true if @c *this precedes @c __arg in the implementation's
111 : : * collation order. */
112 : : // Even with the new abi, on systems that support dlopen
113 : : // we can run into cases where type_info names aren't merged,
114 : : // so we still need to do string comparison.
115 : : bool before(const type_info& __arg) const _GLIBCXX_NOEXCEPT
116 : : { return (__name[0] == '*' && __arg.__name[0] == '*')
117 : : ? __name < __arg.__name
118 : : : __builtin_strcmp (__name, __arg.__name) < 0; }
119 : :
120 : 0 : bool operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT
121 : : {
122 : 0 : return ((__name == __arg.__name)
123 [ # # ][ # # ]: 0 : || (__name[0] != '*' &&
[ # # ]
124 : 0 : __builtin_strcmp (__name, __arg.__name) == 0));
125 : : }
126 : : #else
127 : : // On some targets we can rely on type_info's NTBS being unique,
128 : : // and therefore address comparisons are sufficient.
129 : : bool before(const type_info& __arg) const _GLIBCXX_NOEXCEPT
130 : : { return __name < __arg.__name; }
131 : :
132 : : bool operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT
133 : : { return __name == __arg.__name; }
134 : : #endif
135 : : #endif
136 : : bool operator!=(const type_info& __arg) const _GLIBCXX_NOEXCEPT
137 : : { return !operator==(__arg); }
138 : :
139 : : #if __cplusplus >= 201103L
140 : : size_t hash_code() const noexcept
141 : : {
142 : : # if !__GXX_MERGED_TYPEINFO_NAMES
143 : : return _Hash_bytes(name(), __builtin_strlen(name()),
144 : : static_cast<size_t>(0xc70f6907UL));
145 : : # else
146 : : return reinterpret_cast<size_t>(__name);
147 : : # endif
148 : : }
149 : : #endif // C++11
150 : :
151 : : // Return true if this is a pointer type of some kind
152 : : virtual bool __is_pointer_p() const;
153 : :
154 : : // Return true if this is a function type
155 : : virtual bool __is_function_p() const;
156 : :
157 : : // Try and catch a thrown type. Store an adjusted pointer to the
158 : : // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
159 : : // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
160 : : // type, then THR_OBJ is the pointer itself. OUTER indicates the
161 : : // number of outer pointers, and whether they were const
162 : : // qualified.
163 : : virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
164 : : unsigned __outer) const;
165 : :
166 : : // Internally used during catch matching
167 : : virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
168 : : void **__obj_ptr) const;
169 : :
170 : : protected:
171 : : const char *__name;
172 : :
173 : : explicit type_info(const char *__n): __name(__n) { }
174 : :
175 : : private:
176 : : /// Assigning type_info is not supported.
177 : : type_info& operator=(const type_info&);
178 : : type_info(const type_info&);
179 : : };
180 : :
181 : : /**
182 : : * @brief Thrown during incorrect typecasting.
183 : : * @ingroup exceptions
184 : : *
185 : : * If you attempt an invalid @c dynamic_cast expression, an instance of
186 : : * this class (or something derived from this class) is thrown. */
187 : 0 : class bad_cast : public exception
188 : : {
189 : : public:
190 : 0 : bad_cast() _GLIBCXX_USE_NOEXCEPT { }
191 : :
192 : : // This declaration is not useless:
193 : : // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
194 : : virtual ~bad_cast() _GLIBCXX_USE_NOEXCEPT;
195 : :
196 : : // See comment in eh_exception.cc.
197 : : virtual const char* what() const _GLIBCXX_USE_NOEXCEPT;
198 : : };
199 : :
200 : : /**
201 : : * @brief Thrown when a NULL pointer in a @c typeid expression is used.
202 : : * @ingroup exceptions
203 : : */
204 : : class bad_typeid : public exception
205 : : {
206 : : public:
207 : : bad_typeid () _GLIBCXX_USE_NOEXCEPT { }
208 : :
209 : : // This declaration is not useless:
210 : : // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
211 : : virtual ~bad_typeid() _GLIBCXX_USE_NOEXCEPT;
212 : :
213 : : // See comment in eh_exception.cc.
214 : : virtual const char* what() const _GLIBCXX_USE_NOEXCEPT;
215 : : };
216 : : } // namespace std
217 : :
218 : : } // extern "C++"
219 : :
220 : : #pragma GCC visibility pop
221 : :
222 : : #endif
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