diff --git a/libcxx/include/__exception/exception_ptr.h b/libcxx/include/__exception/exception_ptr.h index b1fe9a1299ec7..1256a2de2395b 100644 --- a/libcxx/include/__exception/exception_ptr.h +++ b/libcxx/include/__exception/exception_ptr.h @@ -15,6 +15,7 @@ #include <__memory/addressof.h> #include <__memory/construct_at.h> #include <__type_traits/decay.h> +#include <__type_traits/is_pointer.h> #include #include @@ -62,7 +63,7 @@ class _LIBCPP_EXPORTED_FROM_ABI exception_ptr { static exception_ptr __from_native_exception_pointer(void*) _NOEXCEPT; template - friend _LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep) _NOEXCEPT; + friend _LIBCPP_HIDE_FROM_ABI exception_ptr __make_exception_ptr_explicit(_Ep&) _NOEXCEPT; public: // exception_ptr is basically a COW string so it is trivially relocatable. @@ -91,25 +92,20 @@ class _LIBCPP_EXPORTED_FROM_ABI exception_ptr { friend _LIBCPP_EXPORTED_FROM_ABI void rethrow_exception(exception_ptr); }; -template -_LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT { # if _LIBCPP_HAS_EXCEPTIONS -# if _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && __cplusplus >= 201103L +template +_LIBCPP_HIDE_FROM_ABI exception_ptr __make_exception_ptr_explicit(_Ep& __e) _NOEXCEPT { using _Ep2 = __decay_t<_Ep>; - void* __ex = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ep)); -# ifdef __wasm__ - // In Wasm, a destructor returns its argument - (void)__cxxabiv1::__cxa_init_primary_exception( - __ex, const_cast(&typeid(_Ep)), [](void* __p) -> void* { -# else - (void)__cxxabiv1::__cxa_init_primary_exception(__ex, const_cast(&typeid(_Ep)), [](void* __p) { -# endif - std::__destroy_at(static_cast<_Ep2*>(__p)); -# ifdef __wasm__ - return __p; -# endif - }); +# ifdef __wasm__ + auto __cleanup = [](void* __p) -> void* { + std::__destroy_at(static_cast<_Ep2*>(__p)); + return __p; + }; +# else + auto __cleanup = [](void* __p) { std::__destroy_at(static_cast<_Ep2*>(__p)); }; +# endif + (void)__cxxabiv1::__cxa_init_primary_exception(__ex, const_cast(&typeid(_Ep)), __cleanup); try { ::new (__ex) _Ep2(__e); @@ -118,18 +114,46 @@ _LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT { __cxxabiv1::__cxa_free_exception(__ex); return current_exception(); } -# else +} + +template +_LIBCPP_HIDE_FROM_ABI exception_ptr __make_exception_ptr_via_throw(_Ep& __e) _NOEXCEPT { try { throw __e; } catch (...) { return current_exception(); } +} + +template +_LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT { + // Objective-C exceptions are thrown via pointer. When throwing an Objective-C exception, + // Clang generates a call to `objc_exception_throw` instead of the usual `__cxa_throw`. + // That function creates an exception with a special Objective-C typeinfo instead of + // the usual C++ typeinfo, since that is needed to implement the behavior documented + // at [1]). + // + // Because of this special behavior, we can't create an exception via `__cxa_init_primary_exception` + // for Objective-C exceptions, otherwise we'd bypass `objc_exception_throw`. See https://llvm.org/PR135089. + // + // [1]: + // https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/Exceptions/Articles/Exceptions64Bit.html + if _LIBCPP_CONSTEXPR (is_pointer<_Ep>::value) { + return std::__make_exception_ptr_via_throw(__e); + } + +# if _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && !defined(_LIBCPP_CXX03_LANG) + return std::__make_exception_ptr_explicit(__e); +# else + return std::__make_exception_ptr_via_throw(__e); # endif -# else - ((void)__e); +} +# else // !_LIBCPP_HAS_EXCEPTIONS +template +_LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep) _NOEXCEPT { std::abort(); -# endif } +# endif // _LIBCPP_HAS_EXCEPTIONS #else // _LIBCPP_ABI_MICROSOFT diff --git a/libcxx/test/std/language.support/support.exception/propagation/make_exception_ptr.objc.pass.mm b/libcxx/test/std/language.support/support.exception/propagation/make_exception_ptr.objc.pass.mm new file mode 100644 index 0000000000000..05a6698ea1a59 --- /dev/null +++ b/libcxx/test/std/language.support/support.exception/propagation/make_exception_ptr.objc.pass.mm @@ -0,0 +1,44 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +// This test ensures that we can catch an Objective-C++ exception by type when +// throwing an exception created via `std::make_exception_ptr`. +// See http://llvm.org/PR135089. + +// UNSUPPORTED: no-exceptions +// UNSUPPORTED: c++03 + +// This test requires the Objective-C ARC, which is (only?) available on Darwin +// out-of-the-box. +// REQUIRES: has-fobjc-arc && darwin + +// ADDITIONAL_COMPILE_FLAGS: -fobjc-arc + +#include +#include + +#import + +NSError* RecoverException(const std::exception_ptr& exc) { + try { + std::rethrow_exception(exc); + } catch (NSError* error) { + return error; + } catch (...) { + } + return nullptr; +} + +int main(int, char**) { + NSError* error = [NSError errorWithDomain:NSPOSIXErrorDomain code:EPERM userInfo:nil]; + std::exception_ptr exc = std::make_exception_ptr(error); + NSError* recov = RecoverException(exc); + assert(recov != nullptr); + + return 0; +}