OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

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.

From-SVN: r241031
This commit is contained in:
Jonathan Wakely 2016-10-12 12:20:25 +01:00 committed by Jonathan Wakely
parent a15ebbcde0
commit 164b41ebf3
4 changed files with 87 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
libstdc++-v3/ChangeLog
View File

@ -1,3 +1,15 @@
2016-10-12 Jonathan Wakely <jwakely@redhat.com>
* 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.
2016-10-11 Jonathan Wakely <jwakely@redhat.com>
* include/bits/stl_list.h (assign(initializer_list<value_type>)): Call

7
libstdc++-v3/doc/xml/manual/intro.xml
View File

@ -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>

35
libstdc++-v3/include/std/mutex
View File

@ -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

45
libstdc++-v3/testsuite/30_threads/call_once/dr2442.cc Normal file
View File

@ -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();
}