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 /** 00082 * @brief Part of RTTI. 00083 * 00084 * The @c type_info class describes type information generated by 00085 * an implementation. 00086 */ 00087 class type_info 00088 { 00089 public: 00090 /** Destructor first. Being the first non-inline virtual function, this 00091 * controls in which translation unit the vtable is emitted. The 00092 * compiler makes use of that information to know where to emit 00093 * the runtime-mandated type_info structures in the new-abi. */ 00094 virtual ~type_info(); 00095 00096 /** Returns an @e implementation-defined byte string; this is not 00097 * portable between compilers! */ 00098 const char* name() const 00099 { return __name[0] == '*' ? __name + 1 : __name; } 00100 00101 #if !__GXX_TYPEINFO_EQUALITY_INLINE 00102 // In old abi, or when weak symbols are not supported, there can 00103 // be multiple instances of a type_info object for one 00104 // type. Uniqueness must use the _name value, not object address. 00105 bool before(const type_info& __arg) const; 00106 bool operator==(const type_info& __arg) const; 00107 #else 00108 #if !__GXX_MERGED_TYPEINFO_NAMES 00109 /** Returns true if @c *this precedes @c __arg in the implementation's 00110 * collation order. */ 00111 // Even with the new abi, on systems that support dlopen 00112 // we can run into cases where type_info names aren't merged, 00113 // so we still need to do string comparison. 00114 bool before(const type_info& __arg) const 00115 { return (__name[0] == '*' && __arg.__name[0] == '*') 00116 ? __name < __arg.__name 00117 : __builtin_strcmp (__name, __arg.__name) < 0; } 00118 00119 bool operator==(const type_info& __arg) const 00120 { 00121 return ((__name == __arg.__name) 00122 || (__name[0] != '*' && 00123 __builtin_strcmp (__name, __arg.__name) == 0)); 00124 } 00125 #else 00126 // On some targets we can rely on type_info's NTBS being unique, 00127 // and therefore address comparisons are sufficient. 00128 bool before(const type_info& __arg) const 00129 { return __name < __arg.__name; } 00130 00131 bool operator==(const type_info& __arg) const 00132 { return __name == __arg.__name; } 00133 #endif 00134 #endif 00135 bool operator!=(const type_info& __arg) const 00136 { return !operator==(__arg); } 00137 00138 // Return true if this is a pointer type of some kind 00139 virtual bool __is_pointer_p() const; 00140 00141 // Return true if this is a function type 00142 virtual bool __is_function_p() const; 00143 00144 // Try and catch a thrown type. Store an adjusted pointer to the 00145 // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then 00146 // THR_OBJ points to the thrown object. If THR_TYPE is a pointer 00147 // type, then THR_OBJ is the pointer itself. OUTER indicates the 00148 // number of outer pointers, and whether they were const 00149 // qualified. 00150 virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj, 00151 unsigned __outer) const; 00152 00153 // Internally used during catch matching 00154 virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target, 00155 void **__obj_ptr) const; 00156 00157 protected: 00158 const char *__name; 00159 00160 explicit type_info(const char *__n): __name(__n) { } 00161 00162 private: 00163 /// Assigning type_info is not supported. 00164 type_info& operator=(const type_info&); 00165 type_info(const type_info&); 00166 }; 00167 00168 /** 00169 * @brief Thrown during incorrect typecasting. 00170 * @ingroup exceptions 00171 * 00172 * If you attempt an invalid @c dynamic_cast expression, an instance of 00173 * this class (or something derived from this class) is thrown. */ 00174 class bad_cast : public exception 00175 { 00176 public: 00177 bad_cast() throw() { } 00178 00179 // This declaration is not useless: 00180 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118 00181 virtual ~bad_cast() throw(); 00182 00183 // See comment in eh_exception.cc. 00184 virtual const char* what() const throw(); 00185 }; 00186 00187 /** 00188 * @brief Thrown when a NULL pointer in a @c typeid expression is used. 00189 * @ingroup exceptions 00190 */ 00191 class bad_typeid : public exception 00192 { 00193 public: 00194 bad_typeid () 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_typeid() throw(); 00199 00200 // See comment in eh_exception.cc. 00201 virtual const char* what() const throw(); 00202 }; 00203 } // namespace std 00204 00205 #pragma GCC visibility pop 00206 00207 } // extern "C++" 00208 #endif