eadcde8e8f
The new constexpr destructor on std::allocator breaks compilation with Clang in C++2a mode. This only makes it constexpr if the compiler supports the P0784R7 features. * include/bits/allocator.h: Check __cpp_constexpr_dynamic_alloc before making the std::allocator destructor constexpr. * testsuite/20_util/allocator/requirements/constexpr.cc: New test. From-SVN: r277458
324 lines
8.8 KiB
C++
324 lines
8.8 KiB
C++
// Allocators -*- C++ -*-
|
|
|
|
// Copyright (C) 2001-2019 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.
|
|
|
|
// Under Section 7 of GPL version 3, you are granted additional
|
|
// permissions described in the GCC Runtime Library Exception, version
|
|
// 3.1, as published by the Free Software Foundation.
|
|
|
|
// You should have received a copy of the GNU General Public License and
|
|
// a copy of the GCC Runtime Library Exception along with this program;
|
|
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
// <http://www.gnu.org/licenses/>.
|
|
|
|
/*
|
|
* Copyright (c) 1996-1997
|
|
* Silicon Graphics Computer Systems, Inc.
|
|
*
|
|
* Permission to use, copy, modify, distribute and sell this software
|
|
* and its documentation for any purpose is hereby granted without fee,
|
|
* provided that the above copyright notice appear in all copies and
|
|
* that both that copyright notice and this permission notice appear
|
|
* in supporting documentation. Silicon Graphics makes no
|
|
* representations about the suitability of this software for any
|
|
* purpose. It is provided "as is" without express or implied warranty.
|
|
*/
|
|
|
|
/** @file bits/allocator.h
|
|
* This is an internal header file, included by other library headers.
|
|
* Do not attempt to use it directly. @headername{memory}
|
|
*/
|
|
|
|
#ifndef _ALLOCATOR_H
|
|
#define _ALLOCATOR_H 1
|
|
|
|
#include <bits/c++allocator.h> // Define the base class to std::allocator.
|
|
#include <bits/memoryfwd.h>
|
|
#if __cplusplus >= 201103L
|
|
#include <type_traits>
|
|
#endif
|
|
|
|
#define __cpp_lib_incomplete_container_elements 201505
|
|
#if __cplusplus >= 201103L
|
|
# define __cpp_lib_allocator_is_always_equal 201411
|
|
#endif
|
|
|
|
namespace std _GLIBCXX_VISIBILITY(default)
|
|
{
|
|
_GLIBCXX_BEGIN_NAMESPACE_VERSION
|
|
|
|
/**
|
|
* @addtogroup allocators
|
|
* @{
|
|
*/
|
|
|
|
/// allocator<void> specialization.
|
|
template<>
|
|
class allocator<void>
|
|
{
|
|
public:
|
|
typedef void value_type;
|
|
typedef size_t size_type;
|
|
typedef ptrdiff_t difference_type;
|
|
#if __cplusplus <= 201703L
|
|
typedef void* pointer;
|
|
typedef const void* const_pointer;
|
|
|
|
template<typename _Tp1>
|
|
struct rebind
|
|
{ typedef allocator<_Tp1> other; };
|
|
#else
|
|
allocator() = default;
|
|
|
|
template<typename _Up>
|
|
constexpr
|
|
allocator(const allocator<_Up>&) { }
|
|
#endif // ! C++20
|
|
|
|
#if __cplusplus >= 201103L && __cplusplus <= 201703L
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 2103. std::allocator propagate_on_container_move_assignment
|
|
typedef true_type propagate_on_container_move_assignment;
|
|
|
|
typedef true_type is_always_equal;
|
|
|
|
template<typename _Up, typename... _Args>
|
|
void
|
|
construct(_Up* __p, _Args&&... __args)
|
|
noexcept(noexcept(::new((void *)__p)
|
|
_Up(std::forward<_Args>(__args)...)))
|
|
{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
|
|
|
|
template<typename _Up>
|
|
void
|
|
destroy(_Up* __p)
|
|
noexcept(noexcept(__p->~_Up()))
|
|
{ __p->~_Up(); }
|
|
#endif // C++11 to C++17
|
|
};
|
|
|
|
/**
|
|
* @brief The @a standard allocator, as per [20.4].
|
|
*
|
|
* See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator
|
|
* for further details.
|
|
*
|
|
* @tparam _Tp Type of allocated object.
|
|
*/
|
|
template<typename _Tp>
|
|
class allocator : public __allocator_base<_Tp>
|
|
{
|
|
public:
|
|
typedef _Tp value_type;
|
|
typedef size_t size_type;
|
|
typedef ptrdiff_t difference_type;
|
|
#if __cplusplus <= 201703L
|
|
typedef _Tp* pointer;
|
|
typedef const _Tp* const_pointer;
|
|
typedef _Tp& reference;
|
|
typedef const _Tp& const_reference;
|
|
|
|
template<typename _Tp1>
|
|
struct rebind
|
|
{ typedef allocator<_Tp1> other; };
|
|
#endif
|
|
|
|
#if __cplusplus >= 201103L
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 2103. std::allocator propagate_on_container_move_assignment
|
|
typedef true_type propagate_on_container_move_assignment;
|
|
|
|
typedef true_type is_always_equal;
|
|
#endif
|
|
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 3035. std::allocator's constructors should be constexpr
|
|
_GLIBCXX20_CONSTEXPR
|
|
allocator() _GLIBCXX_NOTHROW { }
|
|
|
|
_GLIBCXX20_CONSTEXPR
|
|
allocator(const allocator& __a) _GLIBCXX_NOTHROW
|
|
: __allocator_base<_Tp>(__a) { }
|
|
|
|
#if __cplusplus >= 201103L
|
|
// Avoid implicit deprecation.
|
|
allocator& operator=(const allocator&) = default;
|
|
#endif
|
|
|
|
template<typename _Tp1>
|
|
_GLIBCXX20_CONSTEXPR
|
|
allocator(const allocator<_Tp1>&) _GLIBCXX_NOTHROW { }
|
|
|
|
#if __cpp_constexpr_dynamic_alloc
|
|
constexpr
|
|
#endif
|
|
~allocator() _GLIBCXX_NOTHROW { }
|
|
|
|
#if __cplusplus > 201703L
|
|
[[nodiscard,__gnu__::__always_inline__]]
|
|
constexpr _Tp*
|
|
allocate(size_t __n)
|
|
{
|
|
#ifdef __cpp_lib_is_constant_evaluated
|
|
if (std::is_constant_evaluated())
|
|
return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
|
|
#endif
|
|
return __allocator_base<_Tp>::allocate(__n, 0);
|
|
}
|
|
|
|
[[__gnu__::__always_inline__]]
|
|
constexpr void
|
|
deallocate(_Tp* __p, size_t __n)
|
|
{
|
|
#ifdef __cpp_lib_is_constant_evaluated
|
|
if (std::is_constant_evaluated())
|
|
{
|
|
::operator delete(__p);
|
|
return;
|
|
}
|
|
#endif
|
|
__allocator_base<_Tp>::deallocate(__p, __n);
|
|
}
|
|
#endif // C++20
|
|
|
|
friend _GLIBCXX20_CONSTEXPR bool
|
|
operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW
|
|
{ return true; }
|
|
|
|
friend _GLIBCXX20_CONSTEXPR bool
|
|
operator!=(const allocator&, const allocator&) _GLIBCXX_NOTHROW
|
|
{ return false; }
|
|
|
|
// Inherit everything else.
|
|
};
|
|
|
|
template<typename _T1, typename _T2>
|
|
inline _GLIBCXX20_CONSTEXPR bool
|
|
operator==(const allocator<_T1>&, const allocator<_T2>&)
|
|
_GLIBCXX_NOTHROW
|
|
{ return true; }
|
|
|
|
template<typename _T1, typename _T2>
|
|
inline _GLIBCXX20_CONSTEXPR bool
|
|
operator!=(const allocator<_T1>&, const allocator<_T2>&)
|
|
_GLIBCXX_NOTHROW
|
|
{ return false; }
|
|
|
|
// Invalid allocator<cv T> partial specializations.
|
|
// allocator_traits::rebind_alloc can be used to form a valid allocator type.
|
|
template<typename _Tp>
|
|
class allocator<const _Tp>
|
|
{
|
|
public:
|
|
typedef _Tp value_type;
|
|
template<typename _Up> allocator(const allocator<_Up>&) { }
|
|
};
|
|
|
|
template<typename _Tp>
|
|
class allocator<volatile _Tp>
|
|
{
|
|
public:
|
|
typedef _Tp value_type;
|
|
template<typename _Up> allocator(const allocator<_Up>&) { }
|
|
};
|
|
|
|
template<typename _Tp>
|
|
class allocator<const volatile _Tp>
|
|
{
|
|
public:
|
|
typedef _Tp value_type;
|
|
template<typename _Up> allocator(const allocator<_Up>&) { }
|
|
};
|
|
|
|
/// @} group allocator
|
|
|
|
// Inhibit implicit instantiations for required instantiations,
|
|
// which are defined via explicit instantiations elsewhere.
|
|
#if _GLIBCXX_EXTERN_TEMPLATE
|
|
extern template class allocator<char>;
|
|
extern template class allocator<wchar_t>;
|
|
#endif
|
|
|
|
// Undefine.
|
|
#undef __allocator_base
|
|
|
|
// To implement Option 3 of DR 431.
|
|
template<typename _Alloc, bool = __is_empty(_Alloc)>
|
|
struct __alloc_swap
|
|
{ static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } };
|
|
|
|
template<typename _Alloc>
|
|
struct __alloc_swap<_Alloc, false>
|
|
{
|
|
static void
|
|
_S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT
|
|
{
|
|
// Precondition: swappable allocators.
|
|
if (__one != __two)
|
|
swap(__one, __two);
|
|
}
|
|
};
|
|
|
|
// Optimize for stateless allocators.
|
|
template<typename _Alloc, bool = __is_empty(_Alloc)>
|
|
struct __alloc_neq
|
|
{
|
|
static bool
|
|
_S_do_it(const _Alloc&, const _Alloc&)
|
|
{ return false; }
|
|
};
|
|
|
|
template<typename _Alloc>
|
|
struct __alloc_neq<_Alloc, false>
|
|
{
|
|
static bool
|
|
_S_do_it(const _Alloc& __one, const _Alloc& __two)
|
|
{ return __one != __two; }
|
|
};
|
|
|
|
#if __cplusplus >= 201103L
|
|
template<typename _Tp, bool
|
|
= __or_<is_copy_constructible<typename _Tp::value_type>,
|
|
is_nothrow_move_constructible<typename _Tp::value_type>>::value>
|
|
struct __shrink_to_fit_aux
|
|
{ static bool _S_do_it(_Tp&) noexcept { return false; } };
|
|
|
|
template<typename _Tp>
|
|
struct __shrink_to_fit_aux<_Tp, true>
|
|
{
|
|
static bool
|
|
_S_do_it(_Tp& __c) noexcept
|
|
{
|
|
#if __cpp_exceptions
|
|
try
|
|
{
|
|
_Tp(__make_move_if_noexcept_iterator(__c.begin()),
|
|
__make_move_if_noexcept_iterator(__c.end()),
|
|
__c.get_allocator()).swap(__c);
|
|
return true;
|
|
}
|
|
catch(...)
|
|
{ return false; }
|
|
#else
|
|
return false;
|
|
#endif
|
|
}
|
|
};
|
|
#endif
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace std
|
|
|
|
#endif
|