00001 // RTTI support for -*- C++ -*- 00002 // Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 00003 // 2003, 2004, 2005, 2006, 2007, 2009, 2010 00004 // Free Software Foundation 00005 // 00006 // This file is part of GCC. 00007 // 00008 // GCC is free software; you can redistribute it and/or modify 00009 // it under the terms of the GNU General Public License as published by 00010 // the Free Software Foundation; either version 3, or (at your option) 00011 // any later version. 00012 // 00013 // GCC is distributed in the hope that it will be useful, 00014 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00015 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00016 // GNU General Public License for more details. 00017 // 00018 // Under Section 7 of GPL version 3, you are granted additional 00019 // permissions described in the GCC Runtime Library Exception, version 00020 // 3.1, as published by the Free Software Foundation. 00021 00022 // You should have received a copy of the GNU General Public License and 00023 // a copy of the GCC Runtime Library Exception along with this program; 00024 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00025 // <http://www.gnu.org/licenses/>. 00026 00027 /** @file typeinfo 00028 * This is a Standard C++ Library header. 00029 */ 00030 00031 #ifndef _TYPEINFO 00032 #define _TYPEINFO 00033 00034 #pragma GCC system_header 00035 00036 #include <exception> 00037 00038 #pragma GCC visibility push(default) 00039 00040 extern "C++" { 00041 00042 namespace __cxxabiv1 00043 { 00044 class __class_type_info; 00045 } // namespace __cxxabiv1 00046 00047 // Determine whether typeinfo names for the same type are merged (in which 00048 // case comparison can just compare pointers) or not (in which case strings 00049 // must be compared), and whether comparison is to be implemented inline or 00050 // not. We used to do inline pointer comparison by default if weak symbols 00051 // are available, but even with weak symbols sometimes names are not merged 00052 // when objects are loaded with RTLD_LOCAL, so now we always use strcmp by 00053 // default. For ABI compatibility, we do the strcmp inline if weak symbols 00054 // are available, and out-of-line if not. Out-of-line pointer comparison 00055 // is used where the object files are to be portable to multiple systems, 00056 // some of which may not be able to use pointer comparison, but the 00057 // particular system for which libstdc++ is being built can use pointer 00058 // comparison; in particular for most ARM EABI systems, where the ABI 00059 // specifies out-of-line comparison. The compiler's target configuration 00060 // can override the defaults by defining __GXX_TYPEINFO_EQUALITY_INLINE to 00061 // 1 or 0 to indicate whether or not comparison is inline, and 00062 // __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to indicate whether or not pointer 00063 // comparison can be used. 00064 00065 #ifndef __GXX_MERGED_TYPEINFO_NAMES 00066 // By default, typeinfo names are not merged. 00067 #define __GXX_MERGED_TYPEINFO_NAMES 0 00068 #endif 00069 00070 // By default follow the old inline rules to avoid ABI changes. 00071 #ifndef __GXX_TYPEINFO_EQUALITY_INLINE 00072 #if !__GXX_WEAK__ 00073 #define __GXX_TYPEINFO_EQUALITY_INLINE 0 00074 #else 00075 #define __GXX_TYPEINFO_EQUALITY_INLINE 1 00076 #endif 00077 #endif 00078 00079 namespace std 00080 { 00081 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00082 size_t 00083 _Hash_bytes(const void* __ptr, size_t __len, size_t __seed); 00084 #endif 00085 00086 /** 00087 * @brief Part of RTTI. 00088 * 00089 * The @c type_info class describes type information generated by 00090 * an implementation. 00091 */ 00092 class type_info 00093 { 00094 public: 00095 /** Destructor first. Being the first non-inline virtual function, this 00096 * controls in which translation unit the vtable is emitted. The 00097 * compiler makes use of that information to know where to emit 00098 * the runtime-mandated type_info structures in the new-abi. */ 00099 virtual ~type_info(); 00100 00101 /** Returns an @e implementation-defined byte string; this is not 00102 * portable between compilers! */ 00103 const char* name() const 00104 { return __name[0] == '*' ? __name + 1 : __name; } 00105 00106 #if !__GXX_TYPEINFO_EQUALITY_INLINE 00107 // In old abi, or when weak symbols are not supported, there can 00108 // be multiple instances of a type_info object for one 00109 // type. Uniqueness must use the _name value, not object address. 00110 bool before(const type_info& __arg) const; 00111 bool operator==(const type_info& __arg) const; 00112 #else 00113 #if !__GXX_MERGED_TYPEINFO_NAMES 00114 /** Returns true if @c *this precedes @c __arg in the implementation's 00115 * collation order. */ 00116 // Even with the new abi, on systems that support dlopen 00117 // we can run into cases where type_info names aren't merged, 00118 // so we still need to do string comparison. 00119 bool before(const type_info& __arg) const 00120 { return (__name[0] == '*' && __arg.__name[0] == '*') 00121 ? __name < __arg.__name 00122 : __builtin_strcmp (__name, __arg.__name) < 0; } 00123 00124 bool operator==(const type_info& __arg) const 00125 { 00126 return ((__name == __arg.__name) 00127 || (__name[0] != '*' && 00128 __builtin_strcmp (__name, __arg.__name) == 0)); 00129 } 00130 #else 00131 // On some targets we can rely on type_info's NTBS being unique, 00132 // and therefore address comparisons are sufficient. 00133 bool before(const type_info& __arg) const 00134 { return __name < __arg.__name; } 00135 00136 bool operator==(const type_info& __arg) const 00137 { return __name == __arg.__name; } 00138 #endif 00139 #endif 00140 bool operator!=(const type_info& __arg) const 00141 { return !operator==(__arg); } 00142 00143 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00144 size_t hash_code() const throw() 00145 { 00146 # if !__GXX_MERGED_TYPEINFO_NAMES 00147 return _Hash_bytes(name(), __builtin_strlen(name()), 00148 static_cast<size_t>(0xc70f6907UL)); 00149 # else 00150 return reinterpret_cast<size_t>(__name); 00151 # endif 00152 } 00153 #endif // __GXX_EXPERIMENTAL_CXX0X__ 00154 00155 // Return true if this is a pointer type of some kind 00156 virtual bool __is_pointer_p() const; 00157 00158 // Return true if this is a function type 00159 virtual bool __is_function_p() const; 00160 00161 // Try and catch a thrown type. Store an adjusted pointer to the 00162 // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then 00163 // THR_OBJ points to the thrown object. If THR_TYPE is a pointer 00164 // type, then THR_OBJ is the pointer itself. OUTER indicates the 00165 // number of outer pointers, and whether they were const 00166 // qualified. 00167 virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj, 00168 unsigned __outer) const; 00169 00170 // Internally used during catch matching 00171 virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target, 00172 void **__obj_ptr) const; 00173 00174 protected: 00175 const char *__name; 00176 00177 explicit type_info(const char *__n): __name(__n) { } 00178 00179 private: 00180 /// Assigning type_info is not supported. 00181 type_info& operator=(const type_info&); 00182 type_info(const type_info&); 00183 }; 00184 00185 /** 00186 * @brief Thrown during incorrect typecasting. 00187 * @ingroup exceptions 00188 * 00189 * If you attempt an invalid @c dynamic_cast expression, an instance of 00190 * this class (or something derived from this class) is thrown. */ 00191 class bad_cast : public exception 00192 { 00193 public: 00194 bad_cast() throw() { } 00195 00196 // This declaration is not useless: 00197 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118 00198 virtual ~bad_cast() throw(); 00199 00200 // See comment in eh_exception.cc. 00201 virtual const char* what() const throw(); 00202 }; 00203 00204 /** 00205 * @brief Thrown when a NULL pointer in a @c typeid expression is used. 00206 * @ingroup exceptions 00207 */ 00208 class bad_typeid : public exception 00209 { 00210 public: 00211 bad_typeid () throw() { } 00212 00213 // This declaration is not useless: 00214 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118 00215 virtual ~bad_typeid() throw(); 00216 00217 // See comment in eh_exception.cc. 00218 virtual const char* what() const throw(); 00219 }; 00220 } // namespace std 00221 00222 #pragma GCC visibility pop 00223 00224 } // extern "C++" 00225 #endif