From a56561ac2d88ea0bc0bb6551483c118358762842 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Wed, 29 Oct 2014 18:38:31 +0000 Subject: [PATCH] Use perfect forwarding in std::function invokers. * include/std/functional: (_Function_base::_Function_base()): Use nullptr instead of literal zero. (function::operator=(nullptr_t)): Likewise. (_Function_handler::_M_invoke): Use perfect forwarding for _ArgTypes. (function::_Invoker_type): Likewise. * testsuite/20_util/function/invoke/forwarding.cc: New. From-SVN: r216849 --- libstdc++-v3/ChangeLog | 9 +++ libstdc++-v3/include/std/functional | 20 +++---- .../20_util/function/invoke/forwarding.cc | 56 +++++++++++++++++++ 3 files changed, 75 insertions(+), 10 deletions(-) create mode 100644 libstdc++-v3/testsuite/20_util/function/invoke/forwarding.cc diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index e513ac7a5d5..08c44c3e552 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,12 @@ +2014-10-29 Jonathan Wakely + + * include/std/functional: (_Function_base::_Function_base()): Use + nullptr instead of literal zero. + (function::operator=(nullptr_t)): Likewise. + (_Function_handler::_M_invoke): Use perfect forwarding for _ArgTypes. + (function::_Invoker_type): Likewise. + * testsuite/20_util/function/invoke/forwarding.cc: New. + 2014-10-29 Jonathan Wakely * doc/xml/manual/status_cxx2014.xml: Update TS status. diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional index bed1eea018f..5bc2730c2f5 100644 --- a/libstdc++-v3/include/std/functional +++ b/libstdc++-v3/include/std/functional @@ -1990,7 +1990,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type) } }; - _Function_base() : _M_manager(0) { } + _Function_base() : _M_manager(nullptr) { } ~_Function_base() { @@ -2019,7 +2019,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type) public: static _Res - _M_invoke(const _Any_data& __functor, _ArgTypes... __args) + _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) { return (*_Base::_M_get_pointer(__functor))( std::forward<_ArgTypes>(__args)...); @@ -2034,7 +2034,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type) public: static void - _M_invoke(const _Any_data& __functor, _ArgTypes... __args) + _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) { (*_Base::_M_get_pointer(__functor))( std::forward<_ArgTypes>(__args)...); @@ -2049,7 +2049,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type) public: static _Res - _M_invoke(const _Any_data& __functor, _ArgTypes... __args) + _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) { return __callable_functor(**_Base::_M_get_pointer(__functor))( std::forward<_ArgTypes>(__args)...); @@ -2064,7 +2064,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type) public: static void - _M_invoke(const _Any_data& __functor, _ArgTypes... __args) + _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) { __callable_functor(**_Base::_M_get_pointer(__functor))( std::forward<_ArgTypes>(__args)...); @@ -2081,7 +2081,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type) public: static _Res - _M_invoke(const _Any_data& __functor, _ArgTypes... __args) + _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) { return std::mem_fn(_Base::_M_get_pointer(__functor)->__value)( std::forward<_ArgTypes>(__args)...); @@ -2121,7 +2121,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type) } static void - _M_invoke(const _Any_data& __functor, _ArgTypes... __args) + _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) { std::mem_fn(_Base::_M_get_pointer(__functor)->__value)( std::forward<_ArgTypes>(__args)...); @@ -2275,8 +2275,8 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type) if (_M_manager) { _M_manager(_M_functor, _M_functor, __destroy_functor); - _M_manager = 0; - _M_invoker = 0; + _M_manager = nullptr; + _M_invoker = nullptr; } return *this; } @@ -2395,7 +2395,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type) #endif private: - typedef _Res (*_Invoker_type)(const _Any_data&, _ArgTypes...); + using _Invoker_type = _Res (*)(const _Any_data&, _ArgTypes&&...); _Invoker_type _M_invoker; }; diff --git a/libstdc++-v3/testsuite/20_util/function/invoke/forwarding.cc b/libstdc++-v3/testsuite/20_util/function/invoke/forwarding.cc new file mode 100644 index 00000000000..b6e1b47fb4a --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/function/invoke/forwarding.cc @@ -0,0 +1,56 @@ +// Copyright (C) 2014 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 +// . + +// { dg-options "-std=gnu++11" } + +#include +#include + +struct Counted +{ + Counted() : count(0) { } + Counted(const Counted& c) : count(c.count + 1) { } + int count; +}; + +int func(Counted c) { return c.count; } + +std::function f = func; + +void +test01() +{ + Counted c; + int n = f(c); + // 1 copy invoking function::operator() and 1 copy invoking func + VERIFY( n == 2 ); +} + +void +test02() +{ + int n = f(Counted{}); + // copy elided when invoking function::operator(), 1 copy invoking func + VERIFY( n == 1 ); +} + +int +main() +{ + test01(); + test02(); +} -- 2.30.2