| // RTTI support for -*- C++ -*- |
| // Copyright (C) 1994-2021 Free Software Foundation, Inc. |
| // |
| // This file is part of GCC. |
| // |
| // GCC is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| // |
| // GCC is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| // |
| // Under Section 7 of GPL version 3, you are granted additional |
| // permissions described in the GCC Runtime Library Exception, version |
| // 3.1, as published by the Free Software Foundation. |
| |
| // You should have received a copy of the GNU General Public License and |
| // a copy of the GCC Runtime Library Exception along with this program; |
| // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| // <http://www.gnu.org/licenses/>. |
| |
| /** @file typeinfo |
| * This is a Standard C++ Library header. |
| */ |
| |
| #ifndef _TYPEINFO |
| #define _TYPEINFO |
| |
| #pragma GCC system_header |
| |
| #include <bits/exception.h> |
| #if __cplusplus >= 201103L |
| #include <bits/hash_bytes.h> |
| #endif |
| |
| #pragma GCC visibility push(default) |
| |
| extern "C++" { |
| |
| namespace __cxxabiv1 |
| { |
| class __class_type_info; |
| } // namespace __cxxabiv1 |
| |
| // Determine whether typeinfo names for the same type are merged (in which |
| // case comparison can just compare pointers) or not (in which case strings |
| // must be compared), and whether comparison is to be implemented inline or |
| // not. We used to do inline pointer comparison by default if weak symbols |
| // are available, but even with weak symbols sometimes names are not merged |
| // when objects are loaded with RTLD_LOCAL, so now we always use strcmp by |
| // default. For ABI compatibility, we do the strcmp inline if weak symbols |
| // are available, and out-of-line if not. Out-of-line pointer comparison |
| // is used where the object files are to be portable to multiple systems, |
| // some of which may not be able to use pointer comparison, but the |
| // particular system for which libstdc++ is being built can use pointer |
| // comparison; in particular for most ARM EABI systems, where the ABI |
| // specifies out-of-line comparison. The compiler's target configuration |
| // can override the defaults by defining __GXX_TYPEINFO_EQUALITY_INLINE to |
| // 1 or 0 to indicate whether or not comparison is inline, and |
| // __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to indicate whether or not pointer |
| // comparison can be used. |
| |
| #ifndef __GXX_MERGED_TYPEINFO_NAMES |
| // By default, typeinfo names are not merged. |
| #define __GXX_MERGED_TYPEINFO_NAMES 0 |
| #endif |
| |
| // By default follow the old inline rules to avoid ABI changes. |
| #ifndef __GXX_TYPEINFO_EQUALITY_INLINE |
| #if !__GXX_WEAK__ |
| #define __GXX_TYPEINFO_EQUALITY_INLINE 0 |
| #else |
| #define __GXX_TYPEINFO_EQUALITY_INLINE 1 |
| #endif |
| #endif |
| |
| namespace std |
| { |
| /** |
| * @brief Part of RTTI. |
| * |
| * The @c type_info class describes type information generated by |
| * an implementation. |
| */ |
| class type_info |
| { |
| public: |
| /** Destructor first. Being the first non-inline virtual function, this |
| * controls in which translation unit the vtable is emitted. The |
| * compiler makes use of that information to know where to emit |
| * the runtime-mandated type_info structures in the new-abi. */ |
| virtual ~type_info(); |
| |
| /** Returns an @e implementation-defined byte string; this is not |
| * portable between compilers! */ |
| const char* name() const _GLIBCXX_NOEXCEPT |
| { return __name[0] == '*' ? __name + 1 : __name; } |
| |
| #if !__GXX_TYPEINFO_EQUALITY_INLINE |
| // In old abi, or when weak symbols are not supported, there can |
| // be multiple instances of a type_info object for one |
| // type. Uniqueness must use the _name value, not object address. |
| bool before(const type_info& __arg) const _GLIBCXX_NOEXCEPT; |
| bool operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT; |
| #else |
| #if !__GXX_MERGED_TYPEINFO_NAMES |
| /** Returns true if @c *this precedes @c __arg in the implementation's |
| * collation order. */ |
| // Even with the new abi, on systems that support dlopen |
| // we can run into cases where type_info names aren't merged, |
| // so we still need to do string comparison. |
| bool before(const type_info& __arg) const _GLIBCXX_NOEXCEPT |
| { return (__name[0] == '*' && __arg.__name[0] == '*') |
| ? __name < __arg.__name |
| : __builtin_strcmp (__name, __arg.__name) < 0; } |
| |
| bool operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT |
| { |
| return ((__name == __arg.__name) |
| || (__name[0] != '*' && |
| __builtin_strcmp (__name, __arg.__name) == 0)); |
| } |
| #else |
| // On some targets we can rely on type_info's NTBS being unique, |
| // and therefore address comparisons are sufficient. |
| bool before(const type_info& __arg) const _GLIBCXX_NOEXCEPT |
| { return __name < __arg.__name; } |
| |
| bool operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT |
| { return __name == __arg.__name; } |
| #endif |
| #endif |
| |
| #if __cpp_impl_three_way_comparison < 201907L |
| bool operator!=(const type_info& __arg) const _GLIBCXX_NOEXCEPT |
| { return !operator==(__arg); } |
| #endif |
| |
| #if __cplusplus >= 201103L |
| size_t hash_code() const noexcept |
| { |
| # if !__GXX_MERGED_TYPEINFO_NAMES |
| return _Hash_bytes(name(), __builtin_strlen(name()), |
| static_cast<size_t>(0xc70f6907UL)); |
| # else |
| return reinterpret_cast<size_t>(__name); |
| # endif |
| } |
| #endif // C++11 |
| |
| // Return true if this is a pointer type of some kind |
| virtual bool __is_pointer_p() const; |
| |
| // Return true if this is a function type |
| virtual bool __is_function_p() const; |
| |
| // Try and catch a thrown type. Store an adjusted pointer to the |
| // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then |
| // THR_OBJ points to the thrown object. If THR_TYPE is a pointer |
| // type, then THR_OBJ is the pointer itself. OUTER indicates the |
| // number of outer pointers, and whether they were const |
| // qualified. |
| virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj, |
| unsigned __outer) const; |
| |
| // Internally used during catch matching |
| virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target, |
| void **__obj_ptr) const; |
| |
| protected: |
| const char *__name; |
| |
| explicit type_info(const char *__n): __name(__n) { } |
| |
| private: |
| /// Assigning type_info is not supported. |
| type_info& operator=(const type_info&); |
| type_info(const type_info&); |
| }; |
| |
| /** |
| * @brief Thrown during incorrect typecasting. |
| * @ingroup exceptions |
| * |
| * If you attempt an invalid @c dynamic_cast expression, an instance of |
| * this class (or something derived from this class) is thrown. */ |
| class bad_cast : public exception |
| { |
| public: |
| bad_cast() _GLIBCXX_USE_NOEXCEPT { } |
| |
| // This declaration is not useless: |
| // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118 |
| virtual ~bad_cast() _GLIBCXX_USE_NOEXCEPT; |
| |
| // See comment in eh_exception.cc. |
| virtual const char* what() const _GLIBCXX_USE_NOEXCEPT; |
| }; |
| |
| /** |
| * @brief Thrown when a NULL pointer in a @c typeid expression is used. |
| * @ingroup exceptions |
| */ |
| class bad_typeid : public exception |
| { |
| public: |
| bad_typeid () _GLIBCXX_USE_NOEXCEPT { } |
| |
| // This declaration is not useless: |
| // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118 |
| virtual ~bad_typeid() _GLIBCXX_USE_NOEXCEPT; |
| |
| // See comment in eh_exception.cc. |
| virtual const char* what() const _GLIBCXX_USE_NOEXCEPT; |
| }; |
| } // namespace std |
| |
| } // extern "C++" |
| |
| #pragma GCC visibility pop |
| |
| #endif |