1 // RTTI support for -*- C++ -*- 2 // Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 3 // 2003, 2004, 2005, 2006, 2007, 2009 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 #include <exception> 35 36 #pragma GCC visibility push(default) 37 38 extern "C++" { 39 40 namespace __cxxabiv1 41 { 42 class __class_type_info; 43 } // namespace __cxxabiv1 44 45 // Determine whether typeinfo names for the same type are merged (in which 46 // case comparison can just compare pointers) or not (in which case 47 // strings must be compared and g++.dg/abi/local1.C will fail), and 48 // whether comparison is to be implemented inline or not. By default we 49 // use inline pointer comparison if weak symbols are available, and 50 // out-of-line strcmp if not. Out-of-line pointer comparison is used 51 // where the object files are to be portable to multiple systems, some of 52 // which may not be able to use pointer comparison, but the particular 53 // system for which libstdc++ is being built can use pointer comparison; 54 // in particular for most ARM EABI systems, where the ABI specifies 55 // out-of-line comparison. Inline strcmp is not currently supported. The 56 // compiler's target configuration can override the defaults by defining 57 // __GXX_TYPEINFO_EQUALITY_INLINE to 1 or 0 to indicate whether or not 58 // comparison is inline, and __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to 59 // indicate whether or not pointer comparison can be used. 60 61 #ifndef __GXX_MERGED_TYPEINFO_NAMES 62 #if !__GXX_WEAK__ 63 // If weak symbols are not supported, typeinfo names are not merged. 64 #define __GXX_MERGED_TYPEINFO_NAMES 0 65 #else 66 // On platforms that support weak symbols, typeinfo names are merged. 67 #define __GXX_MERGED_TYPEINFO_NAMES 1 68 #endif 69 #endif 70 71 // By default follow the same rules as for __GXX_MERGED_TYPEINFO_NAMES. 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 const char* name() const 100 { return __name; } 101 102 #if !__GXX_TYPEINFO_EQUALITY_INLINE 103 bool before(const type_info& __arg) const; 104 105 // 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 operator==(const type_info& __arg) const; 109 #else 110 #if !__GXX_MERGED_TYPEINFO_NAMES 111 #error "Inline implementation of type_info comparision requires merging of type_info objects" 112 #endif 113 /** Returns true if @c *this precedes @c __arg in the implementation's 114 * collation order. */ 115 // In new abi we can rely on type_info's NTBS being unique, 116 // and therefore address comparisons are sufficient. 117 bool before(const type_info& __arg) const 118 { return __name < __arg.__name; } 119 120 bool operator==(const type_info& __arg) const 121 { return __name == __arg.__name; } 122 #endif 123 bool operator!=(const type_info& __arg) const 124 { return !operator==(__arg); } 125 126 // Return true if this is a pointer type of some kind 127 virtual bool __is_pointer_p() const; 128 129 // Return true if this is a function type 130 virtual bool __is_function_p() const; 131 132 // Try and catch a thrown type. Store an adjusted pointer to the 133 // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then 134 // THR_OBJ points to the thrown object. If THR_TYPE is a pointer 135 // type, then THR_OBJ is the pointer itself. OUTER indicates the 136 // number of outer pointers, and whether they were const 137 // qualified. 138 virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj, 139 unsigned __outer) const; 140 141 // Internally used during catch matching 142 virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target, 143 void **__obj_ptr) const; 144 145 protected: 146 const char *__name; 147 148 explicit type_info(const char *__n): __name(__n) { } 149 150 private: 151 /// Assigning type_info is not supported. 152 type_info& operator=(const type_info&); 153 type_info(const type_info&); 154 }; 155 156 /** 157 * @brief Thrown during incorrect typecasting. 158 * @ingroup exceptions 159 * 160 * If you attempt an invalid @c dynamic_cast expression, an instance of 161 * this class (or something derived from this class) is thrown. */ 162 class bad_cast : public exception 163 { 164 public: 165 bad_cast() throw() { } 166 167 // This declaration is not useless: 168 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118 169 virtual ~bad_cast() throw(); 170 171 // See comment in eh_exception.cc. 172 virtual const char* what() const throw(); 173 }; 174 175 /** 176 * @brief Thrown when a NULL pointer in a @c typeid expression is used. 177 * @ingroup exceptions 178 */ 179 class bad_typeid : public exception 180 { 181 public: 182 bad_typeid () throw() { } 183 184 // This declaration is not useless: 185 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118 186 virtual ~bad_typeid() throw(); 187 188 // See comment in eh_exception.cc. 189 virtual const char* what() const throw(); 190 }; 191 } // namespace std 192 193 #pragma GCC visibility pop 194 195 } // extern "C++" 196 #endif 197
