llvm/llvm/include/llvm/Support/type_traits.h

//===- llvm/Support/type_traits.h - Simplfied type traits -------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file provides useful additions to the standard type_traits library.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_TYPE_TRAITS_H
#define LLVM_SUPPORT_TYPE_TRAITS_H

#include "llvm/Support/Compiler.h"
#include <type_traits>
#include <utility>

namespace llvm {


/// Metafunction that determines whether the given type is either an
/// integral type or an enumeration type, including enum classes.
///
/// Note that this accepts potentially more integral types than is_integral
/// because it is based on being implicitly convertible to an integral type.
/// Also note that enum classes aren't implicitly convertible to integral types,
/// the value may therefore need to be explicitly converted before being used.
template <typename T> class is_integral_or_enum { … };

/// If T is a pointer, just return it. If it is not, return T&.
template<typename T, typename Enable = void>
struct add_lvalue_reference_if_not_pointer { … };

add_lvalue_reference_if_not_pointer<T, std::enable_if_t<std::is_pointer_v<T>>>;

/// If T is a pointer to X, return a pointer to const X. If it is not,
/// return const T.
template<typename T, typename Enable = void>
struct add_const_past_pointer { … };

add_const_past_pointer<T, std::enable_if_t<std::is_pointer_v<T>>>;

template <typename T, typename Enable = void>
struct const_pointer_or_const_ref { … };
const_pointer_or_const_ref<T, std::enable_if_t<std::is_pointer_v<T>>>;

namespace detail {
template<class T>
union trivial_helper { … };

} // end namespace detail

template <typename T>
struct is_copy_assignable { … };

template <typename T>
struct is_move_assignable { … };

} // end namespace llvm

#endif // LLVM_SUPPORT_TYPE_TRAITS_H