v1/__exception/exception_ptr.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___EXCEPTION_EXCEPTION_PTR_H
0010 #define _LIBCPP___EXCEPTION_EXCEPTION_PTR_H
0011
0012 #include <__config>
0013 #include <__cstddef/nullptr_t.h>
0014 #include <__exception/operations.h>
0015 #include <__memory/addressof.h>
0016 #include <__memory/construct_at.h>
0017 #include <__type_traits/decay.h>
0018 #include <cstdlib>
0019 #include <typeinfo>
0020
0021 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0022 #  pragma GCC system_header
0023 #endif
0024
0025 #ifndef _LIBCPP_ABI_MICROSOFT
0026
0027 #  if _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION
0028
0029 namespace __cxxabiv1 {
0030
0031 extern "C" {
0032 _LIBCPP_OVERRIDABLE_FUNC_VIS void* __cxa_allocate_exception(size_t) throw();
0033 _LIBCPP_OVERRIDABLE_FUNC_VIS void __cxa_free_exception(void*) throw();
0034
0035 struct __cxa_exception;
0036 _LIBCPP_OVERRIDABLE_FUNC_VIS __cxa_exception* __cxa_init_primary_exception(
0037     void*,
0038     std::type_info*,
0039 #    if defined(_WIN32)
0040     void(__thiscall*)(void*)) throw();
0041 #    elif defined(__wasm__)
0042     // In Wasm, a destructor returns its argument
0043     void* (*)(void*)) throw();
0044 #    else
0045     void (*)(void*)) throw();
0046 #    endif
0047 }
0048
0049 } // namespace __cxxabiv1
0050
0051 #  endif
0052
0053 #endif
0054
0055 namespace std { // purposefully not using versioning namespace
0056
0057 #ifndef _LIBCPP_ABI_MICROSOFT
0058
0059 class _LIBCPP_EXPORTED_FROM_ABI exception_ptr {
0060   void* __ptr_;
0061
0062   static exception_ptr __from_native_exception_pointer(void*) _NOEXCEPT;
0063
0064   template <class _Ep>
0065   friend _LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep) _NOEXCEPT;
0066
0067 public:
0068   // exception_ptr is basically a COW string.
0069   using __trivially_relocatable _LIBCPP_NODEBUG = exception_ptr;
0070
0071   _LIBCPP_HIDE_FROM_ABI exception_ptr() _NOEXCEPT : __ptr_() {}
0072   _LIBCPP_HIDE_FROM_ABI exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
0073
0074   exception_ptr(const exception_ptr&) _NOEXCEPT;
0075   exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
0076   ~exception_ptr() _NOEXCEPT;
0077
0078   _LIBCPP_HIDE_FROM_ABI explicit operator bool() const _NOEXCEPT { return __ptr_ != nullptr; }
0079
0080   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT {
0081     return __x.__ptr_ == __y.__ptr_;
0082   }
0083
0084   friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT {
0085     return !(__x == __y);
0086   }
0087
0088   friend _LIBCPP_EXPORTED_FROM_ABI exception_ptr current_exception() _NOEXCEPT;
0089   friend _LIBCPP_EXPORTED_FROM_ABI void rethrow_exception(exception_ptr);
0090 };
0091
0092 template <class _Ep>
0093 _LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT {
0094 #  if _LIBCPP_HAS_EXCEPTIONS
0095 #    if _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && __cplusplus >= 201103L
0096   using _Ep2 = __decay_t<_Ep>;
0097
0098   void* __ex = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ep));
0099 #      ifdef __wasm__
0100   // In Wasm, a destructor returns its argument
0101   (void)__cxxabiv1::__cxa_init_primary_exception(
0102       __ex, const_cast<std::type_info*>(&typeid(_Ep)), [](void* __p) -> void* {
0103 #      else
0104   (void)__cxxabiv1::__cxa_init_primary_exception(__ex, const_cast<std::type_info*>(&typeid(_Ep)), [](void* __p) {
0105 #      endif
0106         std::__destroy_at(static_cast<_Ep2*>(__p));
0107 #      ifdef __wasm__
0108         return __p;
0109 #      endif
0110       });
0111
0112   try {
0113     ::new (__ex) _Ep2(__e);
0114     return exception_ptr::__from_native_exception_pointer(__ex);
0115   } catch (...) {
0116     __cxxabiv1::__cxa_free_exception(__ex);
0117     return current_exception();
0118   }
0119 #    else
0120   try {
0121     throw __e;
0122   } catch (...) {
0123     return current_exception();
0124   }
0125 #    endif
0126 #  else
0127   ((void)__e);
0128   std::abort();
0129 #  endif
0130 }
0131
0132 #else // _LIBCPP_ABI_MICROSOFT
0133
0134 class _LIBCPP_EXPORTED_FROM_ABI exception_ptr {
0135   _LIBCPP_DIAGNOSTIC_PUSH
0136   _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-private-field")
0137   void* __ptr1_;
0138   void* __ptr2_;
0139   _LIBCPP_DIAGNOSTIC_POP
0140
0141 public:
0142   exception_ptr() _NOEXCEPT;
0143   exception_ptr(nullptr_t) _NOEXCEPT;
0144   exception_ptr(const exception_ptr& __other) _NOEXCEPT;
0145   exception_ptr& operator=(const exception_ptr& __other) _NOEXCEPT;
0146   exception_ptr& operator=(nullptr_t) _NOEXCEPT;
0147   ~exception_ptr() _NOEXCEPT;
0148   explicit operator bool() const _NOEXCEPT;
0149 };
0150
0151 _LIBCPP_EXPORTED_FROM_ABI bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT;
0152
0153 inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT {
0154   return !(__x == __y);
0155 }
0156
0157 _LIBCPP_EXPORTED_FROM_ABI void swap(exception_ptr&, exception_ptr&) _NOEXCEPT;
0158
0159 _LIBCPP_EXPORTED_FROM_ABI exception_ptr __copy_exception_ptr(void* __except, const void* __ptr);
0160 _LIBCPP_EXPORTED_FROM_ABI exception_ptr current_exception() _NOEXCEPT;
0161 [[__noreturn__]] _LIBCPP_EXPORTED_FROM_ABI void rethrow_exception(exception_ptr);
0162
0163 // This is a built-in template function which automagically extracts the required
0164 // information.
0165 template <class _E>
0166 void* __GetExceptionInfo(_E);
0167
0168 template <class _Ep>
0169 _LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT {
0170   return __copy_exception_ptr(std::addressof(__e), __GetExceptionInfo(__e));
0171 }
0172
0173 #endif // _LIBCPP_ABI_MICROSOFT
0174 } // namespace std
0175
0176 #endif // _LIBCPP___EXCEPTION_EXCEPTION_PTR_H