Remove unused explicit instantiation of __bind_simple

Message ID 20180717131649.GA15252@redhat.com
State New
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Series
  • Remove unused explicit instantiation of __bind_simple
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Commit Message

Jonathan Wakely July 17, 2018, 1:16 p.m.
The explicit instantiation of std::call_once used to require an
instantiation of __bind_simple, but call_once was changed by r241031 to
not use __bind_simple. The instantiation of __bind_simple (and the
definitions it uses) are not needed. They should have been removed
instead of doing the changes in r241111 that kept them compiling.

The use of std::call_once by _Async_state_common::_M_join can be
simplified to use a pointer instead of reference wrapper. The call_once
symbol isn't exported so the change isn't visible outside the library.

	* src/c++11/compatibility-thread-c++0x.cc [_GLIBCXX_SHARED]
	(_Async_state_common::_M_join): Simplify use of std::call_once and
	corresponding explicit instantiation.
	(_Maybe_wrap_member_pointer, _Bind_simple, _Bind_simple_helper)
	(__bind_simple): Remove definitions and explicit instantiation that
	are not required by exported symbols.

Tested powerpc64le-linux, committed to trunk.
commit 8c615f0dcb66beed4cf0d4d17f4ed640664932cb
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Jul 17 13:37:00 2018 +0100

    Remove unused explicit instantiation of __bind_simple
    
    The explicit instantiation of std::call_once used to require an
    instantiation of __bind_simple, but call_once was changed by r241031 to
    not use __bind_simple. The instantiation of __bind_simple (and the
    definitions it uses) are not needed. They should have been removed
    instead of doing the changes in r241111 that kept them compiling.
    
    The use of std::call_once by _Async_state_common::_M_join can be
    simplified to use a pointer instead of reference wrapper. The call_once
    symbol isn't exported so the change isn't visible outside the library.
    
            * src/c++11/compatibility-thread-c++0x.cc [_GLIBCXX_SHARED]
            (_Async_state_common::_M_join): Simplify use of std::call_once and
            corresponding explicit instantiation.
            (_Maybe_wrap_member_pointer, _Bind_simple, _Bind_simple_helper)
            (__bind_simple): Remove definitions and explicit instantiation that
            are not required by exported symbols.

Patch

diff --git a/libstdc++-v3/src/c++11/compatibility-thread-c++0x.cc b/libstdc++-v3/src/c++11/compatibility-thread-c++0x.cc
index 7abbb59877d..e60c8f9bfd6 100644
--- a/libstdc++-v3/src/c++11/compatibility-thread-c++0x.cc
+++ b/libstdc++-v3/src/c++11/compatibility-thread-c++0x.cc
@@ -109,7 +109,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   protected:
     ~_Async_state_common();
     virtual void _M_run_deferred() { _M_join(); }
-    void _M_join() { std::call_once(_M_once, &thread::join, ref(_M_thread)); }
+    void _M_join() { std::call_once(_M_once, &thread::join, &_M_thread); }
     thread _M_thread;
     once_flag _M_once;
   };
@@ -117,84 +117,8 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // Replaced with inline definition in gcc-4.8.0
   __future_base::_Async_state_common::~_Async_state_common() { _M_join(); }
 
-  template<typename _Tp>
-    struct _Maybe_wrap_member_pointer;
-
-  template<typename _Tp, typename _Class>
-    struct _Maybe_wrap_member_pointer<_Tp _Class::*>
-    {
-      typedef _Mem_fn<_Tp _Class::*> type;
-
-      static constexpr type
-      __do_wrap(_Tp _Class::* __pm)
-      { return type(__pm); }
-    };
-
-  template<typename _Signature>
-    struct _Bind_simple;
-
-  template<typename _Callable, typename... _Args>
-    struct _Bind_simple<_Callable(_Args...)>
-    {
-      typedef typename result_of<_Callable(_Args...)>::type result_type;
-
-      template<typename _Tp, typename... _Up>
-        explicit
-        _Bind_simple(_Tp&& __f, _Up&&... __args)
-        : _M_bound(std::forward<_Tp>(__f), std::forward<_Up>(__args)...)
-        { }
-
-      _Bind_simple(const _Bind_simple&) = default;
-      _Bind_simple(_Bind_simple&&) = default;
-
-      result_type
-      operator()()
-      {
-        typedef typename _Build_index_tuple<sizeof...(_Args)>::__type _Indices;
-        return _M_invoke(_Indices());
-      }
-
-    private:
-      template<std::size_t... _Indices>
-        typename result_of<_Callable(_Args...)>::type
-        _M_invoke(_Index_tuple<_Indices...>)
-        {
-         // std::bind always forwards bound arguments as lvalues,
-         // but this type can call functions which only accept rvalues.
-          return std::forward<_Callable>(std::get<0>(_M_bound))(
-              std::forward<_Args>(std::get<_Indices+1>(_M_bound))...);
-        }
-
-      std::tuple<_Callable, _Args...> _M_bound;
-    };
-
-  template<typename _Func, typename... _BoundArgs>
-    struct _Bind_simple_helper
-    {
-      typedef _Maybe_wrap_member_pointer<typename decay<_Func>::type>
-        __maybe_type;
-      typedef typename __maybe_type::type __func_type;
-      typedef _Bind_simple<__func_type(typename decay<_BoundArgs>::type...)>
-               __type;
-    };
-
-  // Simplified version of std::bind for internal use, without support for
-  // unbound arguments, placeholders or nested bind expressions.
-  template<typename _Callable, typename... _Args>
-    typename _Bind_simple_helper<_Callable, _Args...>::__type
-    __bind_simple(_Callable&& __callable, _Args&&... __args)
-    {
-      typedef _Bind_simple_helper<_Callable, _Args...> __helper_type;
-      typedef typename __helper_type::__maybe_type __maybe_type;
-      typedef typename __helper_type::__type __result_type;
-      return __result_type(
-          __maybe_type::__do_wrap( std::forward<_Callable>(__callable)),
-          std::forward<_Args>(__args)...);
-    }
-
-  // Explicit instantiation due to -fno-implicit-instantiation.
-  template void call_once(once_flag&, void (thread::*&&)(), reference_wrapper<thread>&&);
-  template _Bind_simple_helper<void (thread::*)(), reference_wrapper<thread>>::__type __bind_simple(void (thread::*&&)(), reference_wrapper<thread>&&);
+  // Explicit instantiation due to -fno-implicit-templates.
+  template void call_once(once_flag&, void (thread::*&&)(), thread*&&);
 #endif // _GLIBCXX_HAVE_TLS
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std