//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___TYPE_TRAITS_IS_TRIVIALLY_RELOCATABLE_H
#define _LIBCPP___TYPE_TRAITS_IS_TRIVIALLY_RELOCATABLE_H

#include <__config>
#include <__type_traits/enable_if.h>
#include <__type_traits/is_same.h>
#include <__type_traits/is_trivially_copyable.h>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

// A type is trivially relocatable if a move construct + destroy of the original object is equivalent to
// `memcpy(dst, src, sizeof(T))`.
//
// Note that we don't use the __is_trivially_relocatable Clang builtin right now because it does not
// implement the semantics of any current or future trivial relocation proposal and it can lead to
// incorrect optimizations on some platforms (Windows) and supported compilers (AppleClang).
#if __has_builtin(__is_trivially_relocatable) && 0
template <class _Tp, class = void>
struct __libcpp_is_trivially_relocatable : integral_constant<bool, __is_trivially_relocatable(_Tp)> {};
#else
template <class _Tp, class = void>
struct __libcpp_is_trivially_relocatable : is_trivially_copyable<_Tp> {};
#endif

// __trivially_relocatable on libc++'s builtin types does not currently return the right answer with PFP
// in tagged mode, in which the address of the pointer is used as part of the pointer encoding.
#if !defined(__POINTER_FIELD_PROTECTION_TAGGED__)
template <class _Tp>
struct __libcpp_is_trivially_relocatable<_Tp,
                                         __enable_if_t<is_same<_Tp, typename _Tp::__trivially_relocatable>::value> >
    : true_type {};
#endif

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___TYPE_TRAITS_IS_TRIVIALLY_RELOCATABLE_H
