[libcxx-commits] [libcxx] a06591b - [libc++][type_traits] P2674R1: A trait for implicit lifetime types (#106870)
via libcxx-commits
libcxx-commits at lists.llvm.org
Tue Oct 8 23:19:17 PDT 2024
Author: Hristo Hristov
Date: 2024-10-09T08:19:14+02:00
New Revision: a06591b4d4fb270b587fc5ef67b5a03dad752b40
URL: https://github.com/llvm/llvm-project/commit/a06591b4d4fb270b587fc5ef67b5a03dad752b40
DIFF: https://github.com/llvm/llvm-project/commit/a06591b4d4fb270b587fc5ef67b5a03dad752b40.diff
LOG: [libc++][type_traits] P2674R1: A trait for implicit lifetime types (#106870)
Implements P2674R1: https://wg21.link/P2674R1
- https://eel.is/c++draft/type.traits
- https://eel.is/c++draft/meta.type.synop
- https://eel.is/c++draft/meta.unary.prop
- https://eel.is/c++draft/support.limits
- https://eel.is/c++draft/version.syn
Implementation details:
- Uses compiler intrinsic `__builtin_is_implicit_lifetime`:
- https://github.com/llvm/llvm-project/pull/101807
- Tests based on:
-
https://github.com/llvm/llvm-project/blob/d213981c80626698a07b11ce872acba098a863d4/clang/test/SemaCXX/type-traits.cpp#L1989
References:
- Implicit-lifetime
- Implicit-lifetime types [basic.types.general]/9:
https://eel.is/c++draft/basic.types.general
- Implicit-lifetime class [class.prop]/9:
https://eel.is/c++draft/class.prop
- P0593R6 Implicit creation of objects for low-level object
manipulation: https://wg21.link/P0593R6
- P1010R1 Container support for implicit lifetime types:
https://wg21.link/P1010R1
- P0593R6 Implicit creation of objects for low-level object
manipulation: https://wg21.link/P0593R6
Closes: #105259
---------
Co-authored-by: Hristo Hristov <zingam at outlook.com>
Added:
libcxx/include/__type_traits/is_implicit_lifetime.h
libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.pass.cpp
libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.verify.cpp
Modified:
libcxx/docs/FeatureTestMacroTable.rst
libcxx/docs/ReleaseNotes/20.rst
libcxx/docs/Status/Cxx23Papers.csv
libcxx/include/CMakeLists.txt
libcxx/include/module.modulemap
libcxx/include/type_traits
libcxx/include/version
libcxx/modules/std/type_traits.inc
libcxx/test/std/language.support/support.limits/support.limits.general/type_traits.version.compile.pass.cpp
libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
libcxx/utils/generate_feature_test_macro_components.py
Removed:
################################################################################
diff --git a/libcxx/docs/FeatureTestMacroTable.rst b/libcxx/docs/FeatureTestMacroTable.rst
index c909a4300db1a6..05b08da5215350 100644
--- a/libcxx/docs/FeatureTestMacroTable.rst
+++ b/libcxx/docs/FeatureTestMacroTable.rst
@@ -336,6 +336,8 @@ Status
---------------------------------------------------------- -----------------
``__cpp_lib_ios_noreplace`` ``202207L``
---------------------------------------------------------- -----------------
+ ``__cpp_lib_is_implicit_lifetime`` ``202302L``
+ ---------------------------------------------------------- -----------------
``__cpp_lib_is_scoped_enum`` ``202011L``
---------------------------------------------------------- -----------------
``__cpp_lib_mdspan`` ``202207L``
diff --git a/libcxx/docs/ReleaseNotes/20.rst b/libcxx/docs/ReleaseNotes/20.rst
index 82c8286b69e23c..dcb1102d81d641 100644
--- a/libcxx/docs/ReleaseNotes/20.rst
+++ b/libcxx/docs/ReleaseNotes/20.rst
@@ -42,6 +42,7 @@ Implemented Papers
- P2609R3: Relaxing Ranges Just A Smidge (`Github <https://github.com/llvm/llvm-project/issues/105253>`__)
- P2985R0: A type trait for detecting virtual base classes (`Github <https://github.com/llvm/llvm-project/issues/105432>`__)
- ``std::jthread`` and ``<stop_token>`` are not guarded behind ``-fexperimental-library`` anymore
+- P2674R1: A trait for implicit lifetime types (`Github <https://github.com/llvm/llvm-project/issues/105259>`__)
Improvements and New Features
-----------------------------
diff --git a/libcxx/docs/Status/Cxx23Papers.csv b/libcxx/docs/Status/Cxx23Papers.csv
index e1d7bb8f37863e..da7b5881877135 100644
--- a/libcxx/docs/Status/Cxx23Papers.csv
+++ b/libcxx/docs/Status/Cxx23Papers.csv
@@ -113,7 +113,7 @@
"`P2572R1 <https://wg21.link/P2572R1>`__","``std::format`` fill character allowances","2023-02 (Issaquah)","|Complete|","17.0",""
"`P2693R1 <https://wg21.link/P2693R1>`__","Formatting ``thread::id`` and ``stacktrace``","2023-02 (Issaquah)","|Partial|","","The formatter for ``stacktrace`` is not implemented, since ``stacktrace`` is not implemented yet"
"`P2679R2 <https://wg21.link/P2679R2>`__","Fixing ``std::start_lifetime_as`` for arrays","2023-02 (Issaquah)","","",""
-"`P2674R1 <https://wg21.link/P2674R1>`__","A trait for implicit lifetime types","2023-02 (Issaquah)","","",""
+"`P2674R1 <https://wg21.link/P2674R1>`__","A trait for implicit lifetime types","2023-02 (Issaquah)","|Complete|","20.0",""
"`P2655R3 <https://wg21.link/P2655R3>`__","``common_reference_t`` of ``reference_wrapper`` Should Be a Reference Type","2023-02 (Issaquah)","","",""
"`P2652R2 <https://wg21.link/P2652R2>`__","Disallow User Specialization of ``allocator_traits``","2023-02 (Issaquah)","|Complete|","19.0",""
"`P2787R1 <https://wg21.link/P2787R1>`__","``pmr::generator`` - Promise Types are not Values","2023-02 (Issaquah)","","",""
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 9bd1b41b8bfac4..c2a597f49e317f 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -787,6 +787,7 @@ set(files
__type_traits/is_floating_point.h
__type_traits/is_function.h
__type_traits/is_fundamental.h
+ __type_traits/is_implicit_lifetime.h
__type_traits/is_implicitly_default_constructible.h
__type_traits/is_integral.h
__type_traits/is_literal_type.h
diff --git a/libcxx/include/__type_traits/is_implicit_lifetime.h b/libcxx/include/__type_traits/is_implicit_lifetime.h
new file mode 100644
index 00000000000000..2aba420bd2b59d
--- /dev/null
+++ b/libcxx/include/__type_traits/is_implicit_lifetime.h
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_IMPLICIT_LIFETIME_H
+#define _LIBCPP___TYPE_TRAITS_IS_IMPLICIT_LIFETIME_H
+
+#include <__config>
+#include <__type_traits/integral_constant.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 23
+# if __has_builtin(__builtin_is_implicit_lifetime)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_implicit_lifetime : public bool_constant<__builtin_is_implicit_lifetime(_Tp)> {};
+
+template <class _Tp>
+inline constexpr bool is_implicit_lifetime_v = __builtin_is_implicit_lifetime(_Tp);
+
+# endif
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___TYPE_TRAITS_IS_IMPLICIT_LIFETIME_H
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
index dee9b0b88b7948..22a1313498e73e 100644
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -200,6 +200,10 @@ module std_core [system] {
header "__type_traits/is_fundamental.h"
export std_core.type_traits.integral_constant
}
+ module is_implicit_lifetime {
+ header "__type_traits/is_implicit_lifetime.h"
+ export std_core.type_traits.integral_constant
+ }
module is_implicitly_default_constructible {
header "__type_traits/is_implicitly_default_constructible.h"
export std_core.type_traits.integral_constant
diff --git a/libcxx/include/type_traits b/libcxx/include/type_traits
index 26c85f2284e2fd..baeed35ca8508b 100644
--- a/libcxx/include/type_traits
+++ b/libcxx/include/type_traits
@@ -137,6 +137,8 @@ namespace std
template <class T> struct is_nothrow_swappable; // C++17
template <class T> struct is_nothrow_destructible;
+ template<class T> struct is_implicit_lifetime; // Since C++23
+
template <class T> struct has_virtual_destructor;
template<class T> struct has_unique_object_representations; // C++17
@@ -374,6 +376,8 @@ namespace std
= is_nothrow_swappable<T>::value; // C++17
template <class T> inline constexpr bool is_nothrow_destructible_v
= is_nothrow_destructible<T>::value; // C++17
+ template<class T>
+ constexpr bool is_implicit_lifetime_v = is_implicit_lifetime<T>::value; // Since C++23
template <class T> inline constexpr bool has_virtual_destructor_v
= has_virtual_destructor<T>::value; // C++17
template<class T> inline constexpr bool has_unique_object_representations_v // C++17
@@ -516,6 +520,10 @@ namespace std
# include <__type_traits/unwrap_ref.h>
#endif
+#if _LIBCPP_STD_VER >= 23
+# include <__type_traits/is_implicit_lifetime.h>
+#endif
+
#include <version>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/version b/libcxx/include/version
index 5d679caac0b3b7..88387e311636c2 100644
--- a/libcxx/include/version
+++ b/libcxx/include/version
@@ -138,6 +138,7 @@ __cpp_lib_ios_noreplace 202207L <ios>
__cpp_lib_is_aggregate 201703L <type_traits>
__cpp_lib_is_constant_evaluated 201811L <type_traits>
__cpp_lib_is_final 201402L <type_traits>
+__cpp_lib_is_implicit_lifetime 202302L <type_traits>
__cpp_lib_is_invocable 201703L <type_traits>
__cpp_lib_is_layout_compatible 201907L <type_traits>
__cpp_lib_is_nothrow_convertible 201806L <type_traits>
@@ -473,6 +474,9 @@ __cpp_lib_void_t 201411L <type_traits>
# define __cpp_lib_forward_like 202207L
# define __cpp_lib_invoke_r 202106L
# define __cpp_lib_ios_noreplace 202207L
+# if __has_builtin(__builtin_is_implicit_lifetime)
+# define __cpp_lib_is_implicit_lifetime 202302L
+# endif
# define __cpp_lib_is_scoped_enum 202011L
# define __cpp_lib_mdspan 202207L
# define __cpp_lib_modules 202207L
diff --git a/libcxx/modules/std/type_traits.inc b/libcxx/modules/std/type_traits.inc
index 485a5ddf63aed0..f544f95c7aaaae 100644
--- a/libcxx/modules/std/type_traits.inc
+++ b/libcxx/modules/std/type_traits.inc
@@ -98,7 +98,9 @@ export namespace std {
using std::is_nothrow_destructible;
- // using std::is_implicit_lifetime;
+#if _LIBCPP_STD_VER >= 23 && __has_builtin(__builtin_is_implicit_lifetime)
+ using std::is_implicit_lifetime;
+#endif
using std::has_virtual_destructor;
@@ -246,7 +248,9 @@ export namespace std {
using std::is_destructible_v;
using std::is_empty_v;
using std::is_final_v;
- // using std::is_implicit_lifetime_v;
+#if _LIBCPP_STD_VER >= 23 && __has_builtin(__builtin_is_implicit_lifetime)
+ using std::is_implicit_lifetime_v;
+#endif
using std::is_move_assignable_v;
using std::is_move_constructible_v;
using std::is_nothrow_assignable_v;
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/type_traits.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/type_traits.version.compile.pass.cpp
index 1cbf2699a95bcc..d9d698ace2b653 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/type_traits.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/type_traits.version.compile.pass.cpp
@@ -23,6 +23,7 @@
__cpp_lib_is_aggregate 201703L [C++17]
__cpp_lib_is_constant_evaluated 201811L [C++20]
__cpp_lib_is_final 201402L [C++14]
+ __cpp_lib_is_implicit_lifetime 202302L [C++23]
__cpp_lib_is_invocable 201703L [C++17]
__cpp_lib_is_layout_compatible 201907L [C++20]
__cpp_lib_is_nothrow_convertible 201806L [C++20]
@@ -75,6 +76,10 @@
# error "__cpp_lib_is_final should not be defined before c++14"
# endif
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined before c++23"
+# endif
+
# ifdef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should not be defined before c++17"
# endif
@@ -179,6 +184,10 @@
# error "__cpp_lib_is_final should have the value 201402L in c++14"
# endif
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined before c++23"
+# endif
+
# ifdef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should not be defined before c++17"
# endif
@@ -301,6 +310,10 @@
# error "__cpp_lib_is_final should have the value 201402L in c++17"
# endif
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined before c++23"
+# endif
+
# ifndef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should be defined in c++17"
# endif
@@ -444,6 +457,10 @@
# error "__cpp_lib_is_final should have the value 201402L in c++20"
# endif
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined before c++23"
+# endif
+
# ifndef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should be defined in c++20"
# endif
@@ -614,6 +631,19 @@
# error "__cpp_lib_is_final should have the value 201402L in c++23"
# endif
+# if __has_builtin(__builtin_is_implicit_lifetime)
+# ifndef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should be defined in c++23"
+# endif
+# if __cpp_lib_is_implicit_lifetime != 202302L
+# error "__cpp_lib_is_implicit_lifetime should have the value 202302L in c++23"
+# endif
+# else
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined when the requirement '__has_builtin(__builtin_is_implicit_lifetime)' is not met!"
+# endif
+# endif
+
# ifndef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should be defined in c++23"
# endif
@@ -796,6 +826,19 @@
# error "__cpp_lib_is_final should have the value 201402L in c++26"
# endif
+# if __has_builtin(__builtin_is_implicit_lifetime)
+# ifndef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should be defined in c++26"
+# endif
+# if __cpp_lib_is_implicit_lifetime != 202302L
+# error "__cpp_lib_is_implicit_lifetime should have the value 202302L in c++26"
+# endif
+# else
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined when the requirement '__has_builtin(__builtin_is_implicit_lifetime)' is not met!"
+# endif
+# endif
+
# ifndef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should be defined in c++26"
# endif
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
index 985ffeffab96db..0614f64a2ef04d 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
@@ -125,6 +125,7 @@
__cpp_lib_is_aggregate 201703L [C++17]
__cpp_lib_is_constant_evaluated 201811L [C++20]
__cpp_lib_is_final 201402L [C++14]
+ __cpp_lib_is_implicit_lifetime 202302L [C++23]
__cpp_lib_is_invocable 201703L [C++17]
__cpp_lib_is_layout_compatible 201907L [C++20]
__cpp_lib_is_nothrow_convertible 201806L [C++20]
@@ -671,6 +672,10 @@
# error "__cpp_lib_is_final should not be defined before c++14"
# endif
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined before c++23"
+# endif
+
# ifdef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should not be defined before c++17"
# endif
@@ -1550,6 +1555,10 @@
# error "__cpp_lib_is_final should have the value 201402L in c++14"
# endif
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined before c++23"
+# endif
+
# ifdef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should not be defined before c++17"
# endif
@@ -2564,6 +2573,10 @@
# error "__cpp_lib_is_final should have the value 201402L in c++17"
# endif
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined before c++23"
+# endif
+
# ifndef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should be defined in c++17"
# endif
@@ -3842,6 +3855,10 @@
# error "__cpp_lib_is_final should have the value 201402L in c++20"
# endif
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined before c++23"
+# endif
+
# ifndef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should be defined in c++20"
# endif
@@ -5306,6 +5323,19 @@
# error "__cpp_lib_is_final should have the value 201402L in c++23"
# endif
+# if __has_builtin(__builtin_is_implicit_lifetime)
+# ifndef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should be defined in c++23"
+# endif
+# if __cpp_lib_is_implicit_lifetime != 202302L
+# error "__cpp_lib_is_implicit_lifetime should have the value 202302L in c++23"
+# endif
+# else
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined when the requirement '__has_builtin(__builtin_is_implicit_lifetime)' is not met!"
+# endif
+# endif
+
# ifndef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should be defined in c++23"
# endif
@@ -7112,6 +7142,19 @@
# error "__cpp_lib_is_final should have the value 201402L in c++26"
# endif
+# if __has_builtin(__builtin_is_implicit_lifetime)
+# ifndef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should be defined in c++26"
+# endif
+# if __cpp_lib_is_implicit_lifetime != 202302L
+# error "__cpp_lib_is_implicit_lifetime should have the value 202302L in c++26"
+# endif
+# else
+# ifdef __cpp_lib_is_implicit_lifetime
+# error "__cpp_lib_is_implicit_lifetime should not be defined when the requirement '__has_builtin(__builtin_is_implicit_lifetime)' is not met!"
+# endif
+# endif
+
# ifndef __cpp_lib_is_invocable
# error "__cpp_lib_is_invocable should be defined in c++26"
# endif
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.pass.cpp
new file mode 100644
index 00000000000000..a6ab77158aae1d
--- /dev/null
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.pass.cpp
@@ -0,0 +1,237 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// These compilers don't support __builtin_is_implicit_lifetime yet.
+// UNSUPPORTED: clang-17, clang-18, clang-19, gcc-14, apple-clang-15, apple-clang-16
+
+// <type_traits>
+
+// template<class T> struct is_implicit_lifetime;
+
+#include <cassert>
+#include <cstddef>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+
+#include "test_macros.h"
+#include "type_algorithms.h"
+
+enum Enum { EV };
+enum SignedEnum : signed int {};
+enum UnsignedEnum : unsigned int {};
+
+enum class EnumClass { EV };
+enum class SignedEnumClass : signed int {};
+enum class UnsignedEnumClass : unsigned int {};
+
+struct EmptyStruct {};
+struct IncompleteStruct;
+
+struct NoEligibleTrivialContructor {
+ NoEligibleTrivialContructor() {};
+ NoEligibleTrivialContructor(const NoEligibleTrivialContructor&) {}
+ NoEligibleTrivialContructor(NoEligibleTrivialContructor&&) {}
+};
+
+struct OnlyDefaultConstructorIsTrivial {
+ OnlyDefaultConstructorIsTrivial() = default;
+ OnlyDefaultConstructorIsTrivial(const OnlyDefaultConstructorIsTrivial&) {}
+ OnlyDefaultConstructorIsTrivial(OnlyDefaultConstructorIsTrivial&&) {}
+};
+
+struct AllContstructorsAreTrivial {
+ AllContstructorsAreTrivial() = default;
+ AllContstructorsAreTrivial(const AllContstructorsAreTrivial&) = default;
+ AllContstructorsAreTrivial(AllContstructorsAreTrivial&&) = default;
+};
+
+struct InheritedNoEligibleTrivialConstructor : NoEligibleTrivialContructor {
+ using NoEligibleTrivialContructor::NoEligibleTrivialContructor;
+};
+
+struct InheritedOnlyDefaultConstructorIsTrivial : OnlyDefaultConstructorIsTrivial {
+ using OnlyDefaultConstructorIsTrivial::OnlyDefaultConstructorIsTrivial;
+};
+
+struct InheritedAllContstructorsAreTrivial : AllContstructorsAreTrivial {
+ using AllContstructorsAreTrivial::AllContstructorsAreTrivial;
+};
+
+struct UserDeclaredDestructor {
+ ~UserDeclaredDestructor() = default;
+};
+
+struct UserProvidedDestructor {
+ ~UserProvidedDestructor() {}
+};
+
+struct UserDeletedDestructorInAggregate {
+ ~UserDeletedDestructorInAggregate() = delete;
+};
+
+struct UserDeletedDestructorInNonAggregate {
+ virtual void NonAggregate();
+ ~UserDeletedDestructorInNonAggregate() = delete;
+};
+
+struct DeletedDestructorViaBaseInAggregate : UserDeletedDestructorInAggregate {};
+struct DeletedDestructorViaBaseInNonAggregate : UserDeletedDestructorInNonAggregate {};
+
+template <bool B>
+struct ConstrainedUserDeclaredDefaultConstructor {
+ ConstrainedUserDeclaredDefaultConstructor()
+ requires B
+ = default;
+ ConstrainedUserDeclaredDefaultConstructor(const ConstrainedUserDeclaredDefaultConstructor&) {}
+};
+
+template <bool B>
+struct ConstrainedUserProvidedDestructor {
+ ~ConstrainedUserProvidedDestructor() = default;
+ ~ConstrainedUserProvidedDestructor()
+ requires B
+ {}
+};
+
+struct StructWithFlexibleArrayMember {
+ int arr[];
+};
+
+struct StructWithZeroSizedArray {
+ int arr[0];
+};
+
+// Test implicit-lifetime type
+template <typename T, bool Expected>
+constexpr void test_is_implicit_lifetime() {
+ assert(std::is_implicit_lifetime<T>::value == Expected);
+ assert(std::is_implicit_lifetime_v<T> == Expected);
+}
+
+// Test pointer, reference, array, etc. types
+template <typename T>
+constexpr void test_is_implicit_lifetime() {
+ test_is_implicit_lifetime<T, true>();
+
+ // cv-qualified
+ test_is_implicit_lifetime<const T, true>();
+ test_is_implicit_lifetime<volatile T, true>();
+
+ test_is_implicit_lifetime<T&, false>();
+ test_is_implicit_lifetime<T&&, false>();
+
+ // Pointer types
+ test_is_implicit_lifetime<T*, true>();
+
+ // Arrays
+ test_is_implicit_lifetime<T[], true>();
+ test_is_implicit_lifetime<T[94], true>();
+}
+
+struct AritmeticTypesTest {
+ template <class T>
+ constexpr void operator()() {
+ test_is_implicit_lifetime<T>();
+ }
+};
+
+constexpr bool test() {
+ // Standard fundamental C++ types
+
+ test_is_implicit_lifetime<std::nullptr_t, true>();
+
+ test_is_implicit_lifetime<void, false>();
+ test_is_implicit_lifetime<const void, false>();
+ test_is_implicit_lifetime<volatile void, false>();
+
+ types::for_each(types::arithmetic_types(), AritmeticTypesTest{});
+
+ test_is_implicit_lifetime<Enum>();
+ test_is_implicit_lifetime<SignedEnum>();
+ test_is_implicit_lifetime<UnsignedEnum>();
+
+ test_is_implicit_lifetime<EnumClass>();
+ test_is_implicit_lifetime<SignedEnumClass>();
+ test_is_implicit_lifetime<UnsignedEnumClass>();
+
+ test_is_implicit_lifetime<void(), false>();
+ test_is_implicit_lifetime<void()&, false>();
+ test_is_implicit_lifetime<void() const, false>();
+ test_is_implicit_lifetime<void (&)(), false>();
+ test_is_implicit_lifetime<void (*)(), true>();
+
+ // Implicit-lifetime class types
+
+ test_is_implicit_lifetime<EmptyStruct>();
+ test_is_implicit_lifetime<int EmptyStruct::*, true>(); // Pointer-to-member
+ test_is_implicit_lifetime<int (EmptyStruct::*)(), true>();
+ test_is_implicit_lifetime<int (EmptyStruct::*)() const, true>();
+ test_is_implicit_lifetime<int (EmptyStruct::*)()&, true>();
+ test_is_implicit_lifetime<int (EmptyStruct::*)()&&, true>();
+
+ test_is_implicit_lifetime<IncompleteStruct[], true>();
+ test_is_implicit_lifetime<IncompleteStruct[82], true>();
+
+ test_is_implicit_lifetime<UserDeclaredDestructor>();
+
+ test_is_implicit_lifetime<UserProvidedDestructor, false>();
+
+ test_is_implicit_lifetime<NoEligibleTrivialContructor, false>();
+
+ test_is_implicit_lifetime<OnlyDefaultConstructorIsTrivial, true>();
+
+ test_is_implicit_lifetime<AllContstructorsAreTrivial, true>();
+
+ test_is_implicit_lifetime<InheritedNoEligibleTrivialConstructor, false>();
+
+ test_is_implicit_lifetime<InheritedOnlyDefaultConstructorIsTrivial, true>();
+
+ test_is_implicit_lifetime<InheritedAllContstructorsAreTrivial, true>();
+
+ test_is_implicit_lifetime<UserDeletedDestructorInAggregate, true>();
+
+ test_is_implicit_lifetime<UserDeletedDestructorInNonAggregate, false>();
+
+ test_is_implicit_lifetime<DeletedDestructorViaBaseInAggregate, true>();
+
+ test_is_implicit_lifetime<DeletedDestructorViaBaseInNonAggregate, false>();
+
+ test_is_implicit_lifetime<ConstrainedUserDeclaredDefaultConstructor<true>, true>();
+ test_is_implicit_lifetime<ConstrainedUserDeclaredDefaultConstructor<false>, false>();
+
+ test_is_implicit_lifetime<ConstrainedUserProvidedDestructor<true>, false>();
+ test_is_implicit_lifetime<ConstrainedUserProvidedDestructor<false>, true>();
+
+ test_is_implicit_lifetime<StructWithFlexibleArrayMember, true>();
+
+ test_is_implicit_lifetime<StructWithZeroSizedArray, true>();
+
+ // C++ standard library types
+
+ test_is_implicit_lifetime<std::pair<int, float>>();
+ test_is_implicit_lifetime<std::tuple<int, float>>();
+
+ // Standard C23 types
+
+#ifdef TEST_COMPILER_CLANG
+ test_is_implicit_lifetime<_BitInt(8)>();
+ test_is_implicit_lifetime<_BitInt(128)>();
+#endif
+
+ return true;
+}
+
+int main(int, char**) {
+ test();
+ static_assert(test());
+
+ return 0;
+}
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.verify.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.verify.cpp
new file mode 100644
index 00000000000000..25bba30da612e6
--- /dev/null
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.verify.cpp
@@ -0,0 +1,26 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// These compilers don't support __builtin_is_implicit_lifetime yet.
+// UNSUPPORTED: clang-17, clang-18, clang-19, gcc-14, apple-clang-15, apple-clang-16
+
+// <type_traits>
+
+// template<class T> struct is_implicit_lifetime;
+
+#include <type_traits>
+
+struct IncompleteStruct;
+
+// expected-error@*:* {{incomplete type 'IncompleteStruct' used in type trait expression}}
+static_assert(!std::is_implicit_lifetime<IncompleteStruct>::value);
+
+// expected-error@*:* {{incomplete type 'IncompleteStruct' used in type trait expression}}
+static_assert(!std::is_implicit_lifetime_v<IncompleteStruct>);
diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
index 3b8a52362ede68..db14c1781dc35a 100755
--- a/libcxx/utils/generate_feature_test_macro_components.py
+++ b/libcxx/utils/generate_feature_test_macro_components.py
@@ -742,6 +742,13 @@ def add_version_header(tc):
"values": {"c++14": 201402},
"headers": ["type_traits"],
},
+ {
+ "name": "__cpp_lib_is_implicit_lifetime",
+ "values": {"c++23": 202302},
+ "headers": ["type_traits"],
+ "test_suite_guard": "__has_builtin(__builtin_is_implicit_lifetime)",
+ "libcxx_guard": "__has_builtin(__builtin_is_implicit_lifetime)",
+ },
{
"name": "__cpp_lib_is_invocable",
"values": {"c++17": 201703},
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