LLVM 17.0.0git
type_traits.h
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1//===- llvm/Support/type_traits.h - Simplfied type traits -------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file provides useful additions to the standard type_traits library.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_SUPPORT_TYPE_TRAITS_H
14#define LLVM_SUPPORT_TYPE_TRAITS_H
15
17#include <type_traits>
18#include <utility>
19
20namespace llvm {
21
22
23/// Metafunction that determines whether the given type is either an
24/// integral type or an enumeration type, including enum classes.
25///
26/// Note that this accepts potentially more integral types than is_integral
27/// because it is based on being implicitly convertible to an integral type.
28/// Also note that enum classes aren't implicitly convertible to integral types,
29/// the value may therefore need to be explicitly converted before being used.
30template <typename T> class is_integral_or_enum {
31 using UnderlyingT = std::remove_reference_t<T>;
32
33public:
34 static const bool value =
35 !std::is_class<UnderlyingT>::value && // Filter conversion operators.
36 !std::is_pointer<UnderlyingT>::value &&
37 !std::is_floating_point<UnderlyingT>::value &&
38 (std::is_enum<UnderlyingT>::value ||
39 std::is_convertible<UnderlyingT, unsigned long long>::value);
40};
41
42/// If T is a pointer, just return it. If it is not, return T&.
43template<typename T, typename Enable = void>
45
46template <typename T>
48 T, std::enable_if_t<std::is_pointer<T>::value>> {
49 using type = T;
50};
51
52/// If T is a pointer to X, return a pointer to const X. If it is not,
53/// return const T.
54template<typename T, typename Enable = void>
55struct add_const_past_pointer { using type = const T; };
56
57template <typename T>
58struct add_const_past_pointer<T, std::enable_if_t<std::is_pointer<T>::value>> {
59 using type = const std::remove_pointer_t<T> *;
60};
61
62template <typename T, typename Enable = void>
64 using type = const T &;
65};
66template <typename T>
68 std::enable_if_t<std::is_pointer<T>::value>> {
70};
71
72namespace detail {
73/// Internal utility to detect trivial copy construction.
74template<typename T> union copy_construction_triviality_helper {
79};
80/// Internal utility to detect trivial move construction.
81template<typename T> union move_construction_triviality_helper {
86};
87
88template<class T>
91};
92
93} // end namespace detail
94
95/// An implementation of `std::is_trivially_copy_constructible` since we have
96/// users with STLs that don't yet include it.
97template <typename T>
99 : std::is_copy_constructible<
100 ::llvm::detail::copy_construction_triviality_helper<T>> {};
101template <typename T>
102struct is_trivially_copy_constructible<T &> : std::true_type {};
103template <typename T>
104struct is_trivially_copy_constructible<T &&> : std::false_type {};
105
106/// An implementation of `std::is_trivially_move_constructible` since we have
107/// users with STLs that don't yet include it.
108template <typename T>
110 : std::is_move_constructible<
111 ::llvm::detail::move_construction_triviality_helper<T>> {};
112template <typename T>
113struct is_trivially_move_constructible<T &> : std::true_type {};
114template <typename T>
115struct is_trivially_move_constructible<T &&> : std::true_type {};
116
117
118template <typename T>
120 template<class F>
121 static auto get(F*) -> decltype(std::declval<F &>() = std::declval<const F &>(), std::true_type{});
122 static std::false_type get(...);
123 static constexpr bool value = decltype(get((T*)nullptr))::value;
124};
125
126template <typename T>
128 template<class F>
129 static auto get(F*) -> decltype(std::declval<F &>() = std::declval<F &&>(), std::true_type{});
130 static std::false_type get(...);
131 static constexpr bool value = decltype(get((T*)nullptr))::value;
132};
133
134} // end namespace llvm
135
136#endif // LLVM_SUPPORT_TYPE_TRAITS_H
#define F(x, y, z)
Definition: MD5.cpp:55
#define T
Metafunction that determines whether the given type is either an integral type or an enumeration type...
Definition: type_traits.h:30
static const bool value
Definition: type_traits.h:34
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
Definition: BitVector.h:851
If T is a pointer to X, return a pointer to const X.
Definition: type_traits.h:55
If T is a pointer, just return it. If it is not, return T&.
Definition: type_traits.h:44
static constexpr bool value
Definition: type_traits.h:123
static auto get(F *) -> decltype(std::declval< F & >()=std::declval< const F & >(), std::true_type{})
static std::false_type get(...)
static std::false_type get(...)
static auto get(F *) -> decltype(std::declval< F & >()=std::declval< F && >(), std::true_type{})
static constexpr bool value
Definition: type_traits.h:131
An implementation of std::is_trivially_copy_constructible since we have users with STLs that don't ye...
Definition: type_traits.h:100
An implementation of std::is_trivially_move_constructible since we have users with STLs that don't ye...
Definition: type_traits.h:111
Internal utility to detect trivial copy construction.
Definition: type_traits.h:74
copy_construction_triviality_helper(const copy_construction_triviality_helper &)=default
Internal utility to detect trivial move construction.
Definition: type_traits.h:81
move_construction_triviality_helper(move_construction_triviality_helper &&)=default