From f8cba3aaaef329e00f8af4364765274205402be9 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Thu, 11 May 2017 14:21:07 +0100 Subject: [PATCH] PR libstdc++/80285 optimize std::make_shared for -fno-rtti PR libstdc++/80285 * include/bits/shared_ptr_base.h (_Sp_make_shared_tag::_S_ti): Define function to get unique fake std::type_info reference. (_Sp_counted_ptr_inplace::_M_get_deleter) [!__cpp_rtti]: Compare to _S_ti() fake reference. (__shared_ptr(_Sp_make_shared_tag, const Alloc&, Args&&...)): Share single implementation with or without RTTI enable. [!__cpp_rtti]: Pass fake reference to _M_get_deleter. * testsuite/20_util/shared_ptr/creation/alloc.cc: Change expected allocation and deallocation counts. * testsuite/20_util/shared_ptr/creation/single_allocation.cc: New. * testsuite/20_util/shared_ptr/creation/single_allocation_no_rtti.cc: New. From-SVN: r247905 --- libstdc++-v3/ChangeLog | 16 +++++ libstdc++-v3/include/bits/shared_ptr_base.h | 64 ++++++++----------- .../20_util/shared_ptr/creation/alloc.cc | 6 +- .../shared_ptr/creation/single_allocation.cc | 55 ++++++++++++++++ .../creation/single_allocation_no_rtti.cc | 56 ++++++++++++++++ 5 files changed, 158 insertions(+), 39 deletions(-) create mode 100644 libstdc++-v3/testsuite/20_util/shared_ptr/creation/single_allocation.cc create mode 100644 libstdc++-v3/testsuite/20_util/shared_ptr/creation/single_allocation_no_rtti.cc diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index e39cfecb84d..298d35182e6 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,19 @@ +2017-05-11 Jonathan Wakely + + PR libstdc++/80285 + * include/bits/shared_ptr_base.h (_Sp_make_shared_tag::_S_ti): Define + function to get unique fake std::type_info reference. + (_Sp_counted_ptr_inplace::_M_get_deleter) [!__cpp_rtti]: Compare to + _S_ti() fake reference. + (__shared_ptr(_Sp_make_shared_tag, const Alloc&, Args&&...)): Share + single implementation with or without RTTI enable. + [!__cpp_rtti]: Pass fake reference to _M_get_deleter. + * testsuite/20_util/shared_ptr/creation/alloc.cc: Change expected + allocation and deallocation counts. + * testsuite/20_util/shared_ptr/creation/single_allocation.cc: New. + * testsuite/20_util/shared_ptr/creation/single_allocation_no_rtti.cc: + New. + 2017-05-10 François Dumont Bump version namespace. diff --git a/libstdc++-v3/include/bits/shared_ptr_base.h b/libstdc++-v3/include/bits/shared_ptr_base.h index c32cd0f3cf0..69185794a85 100644 --- a/libstdc++-v3/include/bits/shared_ptr_base.h +++ b/libstdc++-v3/include/bits/shared_ptr_base.h @@ -68,6 +68,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION #pragma GCC diagnostic pop #endif +#if !__cpp_rtti + class type_info; +#endif + /** * @brief Exception possibly thrown by @c shared_ptr. * @ingroup exceptions @@ -498,7 +502,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // helpers for make_shared / allocate_shared - struct _Sp_make_shared_tag { }; + struct _Sp_make_shared_tag + { +#if !__cpp_rtti + private: + template + friend class __shared_ptr; + template + friend class _Sp_counted_ptr_inplace; + + static const type_info& + _S_ti() noexcept + { + static constexpr _Sp_make_shared_tag __tag; + return reinterpret_cast(__tag); + } +#endif + }; template class _Sp_counted_ptr_inplace final : public _Sp_counted_base<_Lp> @@ -551,8 +571,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { #if __cpp_rtti if (__ti == typeid(_Sp_make_shared_tag)) - return const_cast::type*>(_M_ptr()); +#else + if (&__ti == &_Sp_make_shared_tag::_S_ti()) #endif + return const_cast::type*>(_M_ptr()); return nullptr; } @@ -1295,7 +1317,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const { return _M_refcount._M_less(__rhs._M_refcount); } -#if __cpp_rtti protected: // This constructor is non-standard, it is used by allocate_shared. template @@ -1306,43 +1327,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { // _M_ptr needs to point to the newly constructed object. // This relies on _Sp_counted_ptr_inplace::_M_get_deleter. +#if __cpp_rtti void* __p = _M_refcount._M_get_deleter(typeid(__tag)); - _M_ptr = static_cast<_Tp*>(__p); - _M_enable_shared_from_this_with(_M_ptr); - } #else - template - struct _Deleter - { - void operator()(typename _Alloc::value_type* __ptr) - { - __allocated_ptr<_Alloc> __guard{ _M_alloc, __ptr }; - allocator_traits<_Alloc>::destroy(_M_alloc, __guard.get()); - } - _Alloc _M_alloc; - }; - - template - __shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a, - _Args&&... __args) - : _M_ptr(), _M_refcount() - { - typedef typename allocator_traits<_Alloc>::template - rebind_traits::type> __traits; - _Deleter __del = { __a }; - auto __guard = std::__allocate_guarded(__del._M_alloc); - auto __ptr = __guard.get(); - // _GLIBCXX_RESOLVE_LIB_DEFECTS - // 2070. allocate_shared should use allocator_traits::construct - __traits::construct(__del._M_alloc, __ptr, - std::forward<_Args>(__args)...); - __guard = nullptr; - __shared_count<_Lp> __count(__ptr, __del, __del._M_alloc); - _M_refcount._M_swap(__count); - _M_ptr = __ptr; + void* __p = _M_refcount._M_get_deleter(_Sp_make_shared_tag::_S_ti()); +#endif + _M_ptr = static_cast<_Tp*>(__p); _M_enable_shared_from_this_with(_M_ptr); } -#endif template diff --git a/libstdc++-v3/testsuite/20_util/shared_ptr/creation/alloc.cc b/libstdc++-v3/testsuite/20_util/shared_ptr/creation/alloc.cc index b17387f11bc..7e53e41a72f 100644 --- a/libstdc++-v3/testsuite/20_util/shared_ptr/creation/alloc.cc +++ b/libstdc++-v3/testsuite/20_util/shared_ptr/creation/alloc.cc @@ -63,7 +63,7 @@ test01() VERIFY( p1.get() != 0 ); VERIFY( p1.use_count() == 1 ); VERIFY( A::ctor_count == 1 ); - VERIFY( tracker_allocator_counter::get_allocation_count() > 0 ); + VERIFY( tracker_allocator_counter::get_allocation_count() > sizeof(A) ); } VERIFY( A::ctor_count == A::dtor_count ); VERIFY( tracker_allocator_counter::get_allocation_count() @@ -79,12 +79,12 @@ test02() p1 = std::allocate_shared(tracker_allocator(), 1); VERIFY( A::ctor_count == 1 ); - VERIFY( tracker_allocator_counter::get_allocation_count() > 0 ); + VERIFY( tracker_allocator_counter::get_allocation_count() > sizeof(A) ); p1 = std::allocate_shared(tracker_allocator(), 1, 2.0); VERIFY( A::ctor_count == 2 ); VERIFY( A::dtor_count == 1 ); - VERIFY( tracker_allocator_counter::get_deallocation_count() > 0 ); + VERIFY( tracker_allocator_counter::get_deallocation_count() > sizeof(A) ); p1 = std::allocate_shared(tracker_allocator(), 1, 2.0, '3'); VERIFY( A::ctor_count == 3 ); diff --git a/libstdc++-v3/testsuite/20_util/shared_ptr/creation/single_allocation.cc b/libstdc++-v3/testsuite/20_util/shared_ptr/creation/single_allocation.cc new file mode 100644 index 00000000000..51b6b1bc751 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/shared_ptr/creation/single_allocation.cc @@ -0,0 +1,55 @@ +// Copyright (C) 2017 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-do run { target c++11 } } + +#include +#include + +int counter = 0; + +template +struct Alloc : std::allocator +{ + template + struct rebind { using other = Alloc; }; + + Alloc() = default; + + template + Alloc(const Alloc&) { } + + T* allocate(std::size_t n) + { + ++counter; + return std::allocator::allocate(n); + } +}; + + +void +test01() +{ + std::allocate_shared(Alloc()); + VERIFY( counter == 1 ); +} + +int +main() +{ + test01(); +} diff --git a/libstdc++-v3/testsuite/20_util/shared_ptr/creation/single_allocation_no_rtti.cc b/libstdc++-v3/testsuite/20_util/shared_ptr/creation/single_allocation_no_rtti.cc new file mode 100644 index 00000000000..ba94f3cb90e --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/shared_ptr/creation/single_allocation_no_rtti.cc @@ -0,0 +1,56 @@ +// Copyright (C) 2017 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 "-fno-rtti" } +// { dg-do run { target c++11 } } + +#include +#include + +int counter = 0; + +template +struct Alloc : std::allocator +{ + template + struct rebind { using other = Alloc; }; + + Alloc() = default; + + template + Alloc(const Alloc&) { } + + T* allocate(std::size_t n) + { + ++counter; + return std::allocator::allocate(n); + } +}; + + +void +test01() +{ + std::allocate_shared(Alloc()); + VERIFY( counter == 1 ); +} + +int +main() +{ + test01(); +} -- 2.30.2