1 : // RTTI support for -*- C++ -*-
2 : // Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
3 : // 2003, 2004, 2005, 2006, 2007
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 2, 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 : // You should have received a copy of the GNU General Public License
19 : // along with GCC; see the file COPYING. If not, write to
20 : // the Free Software Foundation, 51 Franklin Street, Fifth Floor,
21 : // Boston, MA 02110-1301, USA.
22 :
23 : // As a special exception, you may use this file as part of a free software
24 : // library without restriction. Specifically, if other files instantiate
25 : // templates or use macros or inline functions from this file, or you compile
26 : // this file and link it with other files to produce an executable, this
27 : // file does not by itself cause the resulting executable to be covered by
28 : // the GNU General Public License. This exception does not however
29 : // invalidate any other reasons why the executable file might be covered by
30 : // the GNU General Public License.
31 :
32 : /** @file typeinfo
33 : * This is a Standard C++ Library header.
34 : */
35 :
36 : #ifndef _TYPEINFO
37 : #define _TYPEINFO
38 :
39 : #include <exception>
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
52 : // strings must be compared and g++.dg/abi/local1.C will fail), and
53 : // whether comparison is to be implemented inline or not. By default we
54 : // use inline pointer comparison if weak symbols are available, and
55 : // out-of-line strcmp if not. Out-of-line pointer comparison is used
56 : // where the object files are to be portable to multiple systems, some of
57 : // which may not be able to use pointer comparison, but the particular
58 : // system for which libstdc++ is being built can use pointer comparison;
59 : // in particular for most ARM EABI systems, where the ABI specifies
60 : // out-of-line comparison. Inline strcmp is not currently supported. The
61 : // compiler's target configuration can override the defaults by defining
62 : // __GXX_TYPEINFO_EQUALITY_INLINE to 1 or 0 to indicate whether or not
63 : // comparison is inline, and __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to
64 : // indicate whether or not pointer comparison can be used.
65 :
66 : #ifndef __GXX_MERGED_TYPEINFO_NAMES
67 : #if !__GXX_WEAK__
68 : // If weak symbols are not supported, typeinfo names are not merged.
69 : #define __GXX_MERGED_TYPEINFO_NAMES 0
70 : #else
71 : // On platforms that support weak symbols, typeinfo names are merged.
72 : #define __GXX_MERGED_TYPEINFO_NAMES 1
73 : #endif
74 : #endif
75 :
76 : // By default follow the same rules as for __GXX_MERGED_TYPEINFO_NAMES.
77 : #ifndef __GXX_TYPEINFO_EQUALITY_INLINE
78 : #if !__GXX_WEAK__
79 : #define __GXX_TYPEINFO_EQUALITY_INLINE 0
80 : #else
81 : #define __GXX_TYPEINFO_EQUALITY_INLINE 1
82 : #endif
83 : #endif
84 :
85 : namespace std
86 : {
87 : /**
88 : * @brief Part of RTTI.
89 : *
90 : * The @c type_info class describes type information generated by
91 : * an implementation.
92 : */
93 : class type_info
94 : {
95 : public:
96 : /** Destructor first. Being the first non-inline virtual function, this
97 : * controls in which translation unit the vtable is emitted. The
98 : * compiler makes use of that information to know where to emit
99 : * the runtime-mandated type_info structures in the new-abi. */
100 : virtual ~type_info();
101 :
102 : /** Returns an @e implementation-defined byte string; this is not
103 : * portable between compilers! */
104 2 : const char* name() const
105 2 : { return __name; }
106 :
107 : #if !__GXX_TYPEINFO_EQUALITY_INLINE
108 : bool before(const type_info& __arg) const;
109 :
110 : // In old abi, or when weak symbols are not supported, there can
111 : // be multiple instances of a type_info object for one
112 : // type. Uniqueness must use the _name value, not object address.
113 : bool operator==(const type_info& __arg) const;
114 : #else
115 : #if !__GXX_MERGED_TYPEINFO_NAMES
116 : #error "Inline implementation of type_info comparision requires merging of type_info objects"
117 : #endif
118 : /** Returns true if @c *this precedes @c __arg in the implementation's
119 : * collation order. */
120 : // In new abi we can rely on type_info's NTBS being unique,
121 : // and therefore address comparisons are sufficient.
122 0 : bool before(const type_info& __arg) const
123 0 : { return __name < __arg.__name; }
124 :
125 : bool operator==(const type_info& __arg) const
126 : { return __name == __arg.__name; }
127 : #endif
128 : bool operator!=(const type_info& __arg) const
129 : { return !operator==(__arg); }
130 :
131 : // Return true if this is a pointer type of some kind
132 : virtual bool __is_pointer_p() const;
133 :
134 : // Return true if this is a function type
135 : virtual bool __is_function_p() const;
136 :
137 : // Try and catch a thrown type. Store an adjusted pointer to the
138 : // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
139 : // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
140 : // type, then THR_OBJ is the pointer itself. OUTER indicates the
141 : // number of outer pointers, and whether they were const
142 : // qualified.
143 : virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
144 : unsigned __outer) const;
145 :
146 : // Internally used during catch matching
147 : virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
148 : void **__obj_ptr) const;
149 :
150 : protected:
151 : const char *__name;
152 :
153 : explicit type_info(const char *__n): __name(__n) { }
154 :
155 : private:
156 : /// Assigning type_info is not supported.
157 : type_info& operator=(const type_info&);
158 : type_info(const type_info&);
159 : };
160 :
161 : /**
162 : * @brief Thrown during incorrect typecasting.
163 : *
164 : * If you attempt an invalid @c dynamic_cast expression, an instance of
165 : * this class (or something derived from this class) is thrown. */
166 : class bad_cast : public exception
167 : {
168 : public:
169 : bad_cast() throw() { }
170 :
171 : // This declaration is not useless:
172 : // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
173 : virtual ~bad_cast() throw();
174 :
175 : // See comment in eh_exception.cc.
176 : virtual const char* what() const throw();
177 : };
178 :
179 : /** If you use a NULL pointer in a @c typeid expression, this is thrown. */
180 : class bad_typeid : public exception
181 : {
182 : public:
183 : bad_typeid () throw() { }
184 :
185 : // This declaration is not useless:
186 : // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
187 : virtual ~bad_typeid() throw();
188 :
189 : // See comment in eh_exception.cc.
190 : virtual const char* what() const throw();
191 : };
192 : } // namespace std
193 :
194 : #pragma GCC visibility pop
195 :
196 : } // extern "C++"
197 : #endif
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