| Message ID | 20140813184057.GF6927@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Aug 13, 2014 at 07:40:57PM +0100, Jonathan Wakely wrote: > This should fix the Hurd bug in PR61841 as well as the problem > described in https://gcc.gnu.org/ml/gcc/2013-09/msg00196.html > > Tested x86_64-linux, committed to trunk. > > This is not suitable for the branches as it requires a new exported > symbol. We could maybe just add some other odr-use of pthread_create, > but it would probably be optimized away anyway. E.g. __asm ("" : : "r" (&pthread_create)); would not be optimized away. > commit 79c721b72b7f9288256cc4bf388cf6b60b65e838 > Author: Jonathan Wakely <jwakely@redhat.com> > Date: Fri Jul 18 15:35:49 2014 +0100 > > PR libstdc++/61841 > * include/std/thread (thread::_M_start_thread): Declare new overload. > (thread::thread<_Callable, _Args...>): Call new overload with an > explicit reference to pthread_create. > * src/c++11/thread.cc (thread::_M_start_thread): Add new overload. > * config/abi/pre/gnu.ver: Export new function. Jakub
On 13/08/14 20:47 +0200, Jakub Jelinek wrote: >On Wed, Aug 13, 2014 at 07:40:57PM +0100, Jonathan Wakely wrote: >> This should fix the Hurd bug in PR61841 as well as the problem >> described in https://gcc.gnu.org/ml/gcc/2013-09/msg00196.html >> >> Tested x86_64-linux, committed to trunk. >> >> This is not suitable for the branches as it requires a new exported >> symbol. We could maybe just add some other odr-use of pthread_create, >> but it would probably be optimized away anyway. > >E.g. __asm ("" : : "r" (&pthread_create)); would not be optimized away. Good idea - thanks. Do we want to do that instead of adding the new exported function I've added on trunk?
On Wed, Aug 13, 2014 at 08:02:22PM +0100, Jonathan Wakely wrote: > On 13/08/14 20:47 +0200, Jakub Jelinek wrote: > >On Wed, Aug 13, 2014 at 07:40:57PM +0100, Jonathan Wakely wrote: > >>This should fix the Hurd bug in PR61841 as well as the problem > >>described in https://gcc.gnu.org/ml/gcc/2013-09/msg00196.html > >> > >>Tested x86_64-linux, committed to trunk. > >> > >>This is not suitable for the branches as it requires a new exported > >>symbol. We could maybe just add some other odr-use of pthread_create, > >>but it would probably be optimized away anyway. > > > >E.g. __asm ("" : : "r" (&pthread_create)); would not be optimized away. > > Good idea - thanks. Do we want to do that instead of adding the new > exported function I've added on trunk? Dunno, you're the maintainer ;) On one side, asm has the disadvantage of being a scheduling barrier (because it is implicitly volatile), on the other side, we are talking about pthread_create call, so perhaps a few lost ticks is nothing compared to that. Jakub
commit 79c721b72b7f9288256cc4bf388cf6b60b65e838
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Fri Jul 18 15:35:49 2014 +0100
PR libstdc++/61841
* include/std/thread (thread::_M_start_thread): Declare new overload.
(thread::thread<_Callable, _Args...>): Call new overload with an
explicit reference to pthread_create.
* src/c++11/thread.cc (thread::_M_start_thread): Add new overload.
* config/abi/pre/gnu.ver: Export new function.
diff --git a/libstdc++-v3/config/abi/pre/gnu.ver b/libstdc++-v3/config/abi/pre/gnu.ver
index ed7a93f..41fac71 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -1372,6 +1372,9 @@ GLIBCXX_3.4.21 {
# std::regex_error::regex_error(std::regex_constants::error_type)
_ZNSt11regex_errorC2ENSt15regex_constants10error_typeE;
+ # void std::thread::_M_start_thread(__shared_base_type, void(*)())
+ _ZNSt6thread15_M_start_threadESt10shared_ptrINS_10_Impl_baseEEPFvvE;
+
} GLIBCXX_3.4.20;
diff --git a/libstdc++-v3/include/std/thread b/libstdc++-v3/include/std/thread
index efcb101..0576347 100644
--- a/libstdc++-v3/include/std/thread
+++ b/libstdc++-v3/include/std/thread
@@ -132,9 +132,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
explicit
thread(_Callable&& __f, _Args&&... __args)
{
+#ifdef GTHR_ACTIVE_PROXY
+ // Create a reference to pthread_create, not just the gthr weak symbol
+ _M_start_thread(_M_make_routine(std::__bind_simple(
+ std::forward<_Callable>(__f),
+ std::forward<_Args>(__args)...)),
+ reinterpret_cast<void(*)()>(&pthread_create));
+#else
_M_start_thread(_M_make_routine(std::__bind_simple(
std::forward<_Callable>(__f),
std::forward<_Args>(__args)...)));
+#endif
}
~thread()
@@ -183,6 +191,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
private:
void
+ _M_start_thread(__shared_base_type, void (*)());
+
+ void
_M_start_thread(__shared_base_type);
template<typename _Callable>
diff --git a/libstdc++-v3/src/c++11/thread.cc b/libstdc++-v3/src/c++11/thread.cc
index 49aacb5..bbcc99c 100644
--- a/libstdc++-v3/src/c++11/thread.cc
+++ b/libstdc++-v3/src/c++11/thread.cc
@@ -137,6 +137,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__throw_system_error(int(errc::operation_not_permitted));
#endif
+ _M_start_thread(__b, nullptr);
+ }
+
+ void
+ thread::_M_start_thread(__shared_base_type __b, void (*)())
+ {
__b->_M_this_ptr = __b;
int __e = __gthread_create(&_M_id._M_thread,
&execute_native_thread_routine, __b.get());