# typeinfo

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    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