This replaces the use of std::__bind_simple by direct calls to std::__invoke so that the arguments are not decay-copied.
* doc/xml/manual/intro.xml: Document LWG 2442 status. * include/std/mutex [_GLIBCXX_HAVE_TLS] (__once_call_impl): Remove. [_GLIBCXX_HAVE_TLS] (_Once_call): Declare primary template and define partial specialization to unpack args and forward to std::invoke. (call_once) [_GLIBCXX_HAVE_TLS]: Use forward_as_tuple and _Once_call instead of __bind_simple and __once_call_impl. (call_once) [!_GLIBCXX_HAVE_TLS]: Use __invoke instead of __bind_simple. * testsuite/30_threads/call_once/dr2442.cc: New test. Tested powerpc64le-linux, committed to trunk.
commit 67819bb3bee8fb170e46b324c65d35b856136cd1 Author: redi <redi@138bc75d-0d04-0410-961f-82ee72b054a4> Date: Wed Oct 12 11:20:25 2016 +0000 Do not copy std:call_once arguments (LWG 2442) * doc/xml/manual/intro.xml: Document LWG 2442 status. * include/std/mutex [_GLIBCXX_HAVE_TLS] (__once_call_impl): Remove. [_GLIBCXX_HAVE_TLS] (_Once_call): Declare primary template and define partial specialization to unpack args and forward to std::invoke. (call_once) [_GLIBCXX_HAVE_TLS]: Use forward_as_tuple and _Once_call instead of __bind_simple and __once_call_impl. (call_once) [!_GLIBCXX_HAVE_TLS]: Use __invoke instead of __bind_simple. * testsuite/30_threads/call_once/dr2442.cc: New test. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@241031 138bc75d-0d04-0410-961f-82ee72b054a4 diff --git a/libstdc++-v3/doc/xml/manual/intro.xml b/libstdc++-v3/doc/xml/manual/intro.xml index 22b792a..528b192 100644 --- a/libstdc++-v3/doc/xml/manual/intro.xml +++ b/libstdc++-v3/doc/xml/manual/intro.xml @@ -1043,6 +1043,13 @@ requirements of the license of GCC. <listitem><para>Define the typedefs. </para></listitem></varlistentry> + <varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="../ext/lwg-defects.html#2442">2442</link>: + <emphasis><code>call_once()</code> shouldn't <code>DECAY_COPY()</code></emphasis> + </term> + <listitem><para>Remove indirection through call wrapper that made copies + of arguments and forward arguments straight to <code>std::invoke</code>. + </para></listitem></varlistentry> + <varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="../ext/lwg-defects.html#2454">2454</link>: <emphasis>Add <code>raw_storage_iterator::base()</code> member </emphasis> diff --git a/libstdc++-v3/include/std/mutex b/libstdc++-v3/include/std/mutex index 7a7bd2e..4c6f036 100644 --- a/libstdc++-v3/include/std/mutex +++ b/libstdc++-v3/include/std/mutex @@ -580,12 +580,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION extern __thread void* __once_callable; extern __thread void (*__once_call)(); - template<typename _Callable> - inline void - __once_call_impl() + template<typename _Tuple, typename _IndexSeq + = typename _Build_index_tuple<tuple_size<_Tuple>::value>::__type> + struct _Once_call; + + template<typename _Tuple, size_t... _Ind> + struct _Once_call<_Tuple, _Index_tuple<_Ind...>> { - (*(_Callable*)__once_callable)(); - } + static void + _S_call() + { + auto& __f_args = *static_cast<_Tuple*>(__once_callable); + std::__invoke(std::get<_Ind>(std::move(__f_args))...); + } + }; #else extern function<void()> __once_functor; @@ -603,16 +611,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION void call_once(once_flag& __once, _Callable&& __f, _Args&&... __args) { + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 2442. call_once() shouldn't DECAY_COPY() #ifdef _GLIBCXX_HAVE_TLS - auto __bound_functor = std::__bind_simple(std::forward<_Callable>(__f), - std::forward<_Args>(__args)...); - __once_callable = std::__addressof(__bound_functor); - __once_call = &__once_call_impl<decltype(__bound_functor)>; + auto __f_args = std::forward_as_tuple( + std::forward<_Callable>(__f), std::forward<_Args>(__args)...); + __once_callable = std::__addressof(__f_args); + __once_call = _Once_call<decltype(__f_args)>::_S_call; #else unique_lock<mutex> __functor_lock(__get_once_mutex()); - auto __callable = std::__bind_simple(std::forward<_Callable>(__f), - std::forward<_Args>(__args)...); - __once_functor = [&]() { __callable(); }; + __once_functor = [&] { + std::__invoke(std::forward<_Callable>(__f), + std::forward<_Args>(__args)...); + }; __set_once_functor_lock_ptr(&__functor_lock); #endif diff --git a/libstdc++-v3/testsuite/30_threads/call_once/dr2442.cc b/libstdc++-v3/testsuite/30_threads/call_once/dr2442.cc new file mode 100644 index 0000000..5b66687 --- /dev/null +++ b/libstdc++-v3/testsuite/30_threads/call_once/dr2442.cc @@ -0,0 +1,45 @@ +// { dg-do run { target *-*-freebsd* *-*-dragonfly* *-*-netbsd* *-*-linux* *-*-gnu* *-*-solaris* *-*-cygwin *-*-rtems* *-*-darwin* powerpc-ibm-aix* } } +// { dg-options "-pthread" { target *-*-freebsd* *-*-dragonfly* *-*-netbsd* *-*-linux* *-*-gnu* *-*-solaris* powerpc-ibm-aix* } } +// { dg-require-effective-target c++11 } +// { dg-require-cstdint "" } +// { dg-require-gthreads "" } + +// Copyright (C) 2016 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library 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. + +// This library 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. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <mutex> +#include <testsuite_hooks.h> + +void f(int& a, int&& b) { a = 1; b = 2; } + +void +test01() +{ + // LWG 2442. call_once() shouldn't DECAY_COPY() + std::once_flag once; + int i = 0; + int j = 0; + call_once(once, f, i, std::move(j)); + VERIFY( i == 1 ); + VERIFY( j == 2 ); +} + +int +main() +{ + test01(); +}