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Optimize make_local_shared to use a single allocation

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This commit is contained in:
Peter Dimov
2017-06-20 04:27:45 +03:00
parent 1f86907a3d
commit 2b5869882a
9 changed files with 316 additions and 62 deletions
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include/boost/smart_ptr/detail/local_counted_base.hpp
+7 -7
View File
@@ -55,9 +55,9 @@ public:
{
}
virtual void destroy() BOOST_SP_NOEXCEPT = 0;
virtual void local_cb_destroy() BOOST_SP_NOEXCEPT = 0;
virtual boost::shared_ptr<void> get_shared_ptr() const BOOST_SP_NOEXCEPT = 0;
virtual boost::shared_ptr<void> local_cb_get_shared_ptr() const BOOST_SP_NOEXCEPT = 0;
void add_ref() BOOST_SP_NOEXCEPT
{
@@ -78,7 +78,7 @@ public:
if( local_use_count_ == 0 )
{
destroy();
local_cb_destroy();
}
}
@@ -112,12 +112,12 @@ public:
#endif
virtual void destroy() BOOST_SP_NOEXCEPT
virtual void local_cb_destroy() BOOST_SP_NOEXCEPT
{
delete this;
}
virtual boost::shared_ptr<void> get_shared_ptr() const BOOST_SP_NOEXCEPT
virtual boost::shared_ptr<void> local_cb_get_shared_ptr() const BOOST_SP_NOEXCEPT
{
return const_pointer_cast<void>( pn_ );
}
@@ -129,12 +129,12 @@ public:
boost::shared_ptr<void const volatile> pn_;
virtual void destroy() BOOST_SP_NOEXCEPT
virtual void local_cb_destroy() BOOST_SP_NOEXCEPT
{
pn_.reset();
}
virtual boost::shared_ptr<void> get_shared_ptr() const BOOST_SP_NOEXCEPT
virtual boost::shared_ptr<void> local_cb_get_shared_ptr() const BOOST_SP_NOEXCEPT
{
return const_pointer_cast<void>( pn_ );
}
include/boost/smart_ptr/local_shared_ptr.hpp
+11 -2
View File
@@ -132,6 +132,10 @@ template< class E, class P, class D, class A > inline void lsp_allocator_constru
pn = pd;
}
struct lsp_internal_constructor_tag
{
};
} // namespace detail
//
@@ -184,6 +188,11 @@ public:
#endif
// internal constructor, used by make_shared
BOOST_CONSTEXPR local_shared_ptr( boost::detail::lsp_internal_constructor_tag, T * px_, boost::detail::local_counted_base * pn_ ) BOOST_SP_NOEXCEPT : px( px_ ), pn( pn_ )
{
}
template<class Y>
explicit local_shared_ptr( Y * p ): px( p ), pn( 0 )
{
@@ -484,7 +493,7 @@ public:
if( pn )
{
return static_pointer_cast<Y>( pn->get_shared_ptr() );
return static_pointer_cast<Y>( pn->local_cb_get_shared_ptr() );
}
else
{
@@ -502,7 +511,7 @@ public:
if( pn )
{
return static_pointer_cast<Y>( pn->get_shared_ptr() );
return static_pointer_cast<Y>( pn->local_cb_get_shared_ptr() );
}
else
{
include/boost/smart_ptr/make_local_shared_object.hpp
+131 -12
View File
@@ -12,6 +12,7 @@
// See http://www.boost.org/libs/smart_ptr/ for documentation.
#include <boost/smart_ptr/local_shared_ptr.hpp>
#include <boost/smart_ptr/detail/local_counted_base.hpp>
#include <boost/smart_ptr/make_shared.hpp>
#include <boost/config.hpp>
#include <utility>
@@ -23,6 +24,8 @@ namespace boost
namespace detail
{
// lsp_if_not_array
template<class T> struct lsp_if_not_array
{
typedef boost::local_shared_ptr<T> type;
@@ -36,26 +39,142 @@ template<class T, std::size_t N> struct lsp_if_not_array<T[N]>
{
};
// lsp_ms_deleter
template<class T, class A> class lsp_ms_deleter: public local_counted_impl_em
{
private:
typedef typename sp_aligned_storage<sizeof(T), ::boost::alignment_of<T>::value>::type storage_type;
storage_type storage_;
A a_;
bool initialized_;
private:
void destroy() BOOST_SP_NOEXCEPT
{
if( initialized_ )
{
T * p = reinterpret_cast< T* >( storage_.data_ );
#if !defined( BOOST_NO_CXX11_ALLOCATOR )
std::allocator_traits<A>::destroy( a_, p );
#else
p->~T();
#endif
initialized_ = false;
}
}
public:
explicit lsp_ms_deleter( A const & a ) BOOST_SP_NOEXCEPT : a_( a ), initialized_( false )
{
}
// optimization: do not copy storage_
lsp_ms_deleter( lsp_ms_deleter const & r ) BOOST_SP_NOEXCEPT : a_( r.a_), initialized_( false )
{
}
~lsp_ms_deleter() BOOST_SP_NOEXCEPT
{
destroy();
}
void operator()( T * ) BOOST_SP_NOEXCEPT
{
destroy();
}
static void operator_fn( T* ) BOOST_SP_NOEXCEPT // operator() can't be static
{
}
void * address() BOOST_SP_NOEXCEPT
{
return storage_.data_;
}
void set_initialized() BOOST_SP_NOEXCEPT
{
initialized_ = true;
}
};
} // namespace detail
template<class T, class... Args> typename boost::detail::lsp_if_not_array<T>::type make_local_shared( Args&&... args )
{
return boost::make_shared<T>( std::forward<Args>(args)... );
}
template<class T> typename boost::detail::lsp_if_not_array<T>::type make_local_shared_noinit()
{
return boost::make_shared_noinit<T>();
}
template<class T, class A, class... Args> typename boost::detail::lsp_if_not_array<T>::type allocate_local_shared( A const & a, Args&&... args )
{
return boost::allocate_shared<T>( a, std::forward<Args>(args)... );
typedef typename std::allocator_traits<A>::template rebind_alloc<T> A2;
A2 a2( a );
typedef boost::detail::lsp_ms_deleter<T, A2> D;
boost::shared_ptr<T> pt( static_cast< T* >( 0 ), boost::detail::sp_inplace_tag<D>(), a2 );
D * pd = static_cast< D* >( pt._internal_get_untyped_deleter() );
void * pv = pd->address();
#if !defined( BOOST_NO_CXX11_ALLOCATOR )
std::allocator_traits<A2>::construct( a2, static_cast< T* >( pv ), std::forward<Args>( args )... );
#else
::new( pv ) T( std::forward<Args>( args )... );
#endif
pd->set_initialized();
T * pt2 = static_cast< T* >( pv );
boost::detail::sp_enable_shared_from_this( &pt, pt2, pt2 );
pd->pn_ = boost::shared_ptr<T>( pt, pt2 );
return boost::local_shared_ptr<T>( boost::detail::lsp_internal_constructor_tag(), pt2, pd );
}
template<class T, class A> typename boost::detail::lsp_if_not_array<T>::type allocate_local_shared_noinit( A const & a )
{
return boost::allocate_shared_noinit<T>( a );
typedef typename std::allocator_traits<A>::template rebind_alloc<T> A2;
A2 a2( a );
typedef boost::detail::lsp_ms_deleter<T, A2> D;
boost::shared_ptr<T> pt( static_cast< T* >( 0 ), boost::detail::sp_inplace_tag<D>(), a2 );
D * pd = static_cast< D* >( pt._internal_get_untyped_deleter() );
void * pv = pd->address();
::new( pv ) T;
pd->set_initialized();
T * pt2 = static_cast< T* >( pv );
boost::detail::sp_enable_shared_from_this( &pt, pt2, pt2 );
pd->pn_ = boost::shared_ptr<T>( pt, pt2 );
return boost::local_shared_ptr<T>( boost::detail::lsp_internal_constructor_tag(), pt2, pd );
}
template<class T, class... Args> typename boost::detail::lsp_if_not_array<T>::type make_local_shared( Args&&... args )
{
return boost::allocate_local_shared<T>( std::allocator<T>(), std::forward<Args>(args)... );
}
template<class T> typename boost::detail::lsp_if_not_array<T>::type make_local_shared_noinit()
{
return boost::allocate_shared_noinit<T>( std::allocator<T>() );
}
} // namespace boost