https://gcc.gnu.org/g:47f0bd269403762ddb71b8c6165b30ace4f70a8b commit r12-8747-g47f0bd269403762ddb71b8c6165b30ace4f70a8b Author: Jonathan Wakely <jwakely@redhat.com> Date: Mon Aug 22 15:42:17 2022 +0100 libstdc++: Fix for explicit copy ctors in <thread> and <future> [PR106695] When I changed std::thread and std::async to avoid unnecessary move construction of temporaries, I introduced a regression where types with an explicit copy constructor could not be passed to std::thread or std::async. The fix is to add a constructor instead of using aggregate initialization of an unnamed temporary. libstdc++-v3/ChangeLog: PR libstdc++/106695 * include/bits/std_thread.h (thread::_State_impl): Forward individual arguments to _Invoker constructor. (thread::_Invoker): Add constructor. Delete copies. * include/std/future (__future_base::_Deferred_state): Forward individual arguments to _Invoker constructor. (__future_base::_Async_state_impl): Likewise. * testsuite/30_threads/async/106695.cc: New test. * testsuite/30_threads/thread/106695.cc: New test. (cherry picked from commit 5abe0657553580bd1b7488dd84d55138a8d9f23c) Diff: --- libstdc++-v3/include/bits/std_thread.h | 8 +++++- libstdc++-v3/include/std/future | 4 +-- libstdc++-v3/testsuite/30_threads/async/106695.cc | 29 ++++++++++++++++++++++ libstdc++-v3/testsuite/30_threads/thread/106695.cc | 21 ++++++++++++++++ 4 files changed, 59 insertions(+), 3 deletions(-) diff --git a/libstdc++-v3/include/bits/std_thread.h b/libstdc++-v3/include/bits/std_thread.h index dd625de3bc3..6adf5e6b467 100644 --- a/libstdc++-v3/include/bits/std_thread.h +++ b/libstdc++-v3/include/bits/std_thread.h @@ -203,7 +203,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename... _Args> _State_impl(_Args&&... __args) - : _M_func{{std::forward<_Args>(__args)...}} + : _M_func(std::forward<_Args>(__args)...) { } void @@ -237,6 +237,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _Tuple> struct _Invoker { + template<typename... _Args> + explicit + _Invoker(_Args&&... __args) + : _M_t(std::forward<_Args>(__args)...) + { } + _Tuple _M_t; template<typename> diff --git a/libstdc++-v3/include/std/future b/libstdc++-v3/include/std/future index 3bdbc636f69..6cda28c84cf 100644 --- a/libstdc++-v3/include/std/future +++ b/libstdc++-v3/include/std/future @@ -1659,7 +1659,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION explicit _Deferred_state(_Args&&... __args) : _M_result(new _Result<_Res>()), - _M_fn{{std::forward<_Args>(__args)...}} + _M_fn(std::forward<_Args>(__args)...) { } private: @@ -1726,7 +1726,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION explicit _Async_state_impl(_Args&&... __args) : _M_result(new _Result<_Res>()), - _M_fn{{std::forward<_Args>(__args)...}} + _M_fn(std::forward<_Args>(__args)...) { _M_thread = std::thread{&_Async_state_impl::_M_run, this}; } diff --git a/libstdc++-v3/testsuite/30_threads/async/106695.cc b/libstdc++-v3/testsuite/30_threads/async/106695.cc new file mode 100644 index 00000000000..74996342dc7 --- /dev/null +++ b/libstdc++-v3/testsuite/30_threads/async/106695.cc @@ -0,0 +1,29 @@ +// { dg-do compile { target c++11 } } +// { dg-require-gthreads "" } + +// PR libstdc++/106695 +// Explicit copy constructor does not work for a parameter passed via std::async + +#include <future> + +struct A { + A() = default; + explicit A(const A&) = default; +}; + +void func(const A&) { } + +void +test_async() +{ + (void) std::async(std::launch::async, func, A{}); + (void) std::async(std::launch::deferred, func, A{}); + (void) std::async(func, A{}); +} + +void +test_task() +{ + std::packaged_task<void(const A&)> task(func); + task(A{}); +} diff --git a/libstdc++-v3/testsuite/30_threads/thread/106695.cc b/libstdc++-v3/testsuite/30_threads/thread/106695.cc new file mode 100644 index 00000000000..97e9e922d8e --- /dev/null +++ b/libstdc++-v3/testsuite/30_threads/thread/106695.cc @@ -0,0 +1,21 @@ +// { dg-do compile { target c++11 } } +// { dg-require-gthreads "" } + +// PR libstdc++/106695 +// Explicit copy constructor does not work for a parameter passed via std::async + +#include <thread> + +struct A { + A() = default; + explicit A(const A&) = default; +}; + +void func(const A&) { } + +void +test_thread() +{ + std::thread t(func, A{}); + t.join(); +}