[libcxx-commits] [libcxx] [libc++] Use enable_if_t to constrain make_unique{, _for_overwrite} (PR #95044)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Mon Jun 10 14:16:11 PDT 2024
https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/95044
This improves the diagnostics a bit by using `enable_if_t` which clang is aware of, instead of a custom SFINAE class, as well as writing the functions in a more canonical style.
As a drive-by this also makes `__is_{,un}bounded_array` variable templates instead of class templates.
>From 16764d98dd57363563f2c8aeb1d09e93504458b7 Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Mon, 10 Jun 2024 23:13:31 +0200
Subject: [PATCH] [libc++] Use enable_if_t to constrain
make_unique{,_for_overwrite}
---
libcxx/include/__memory/shared_ptr.h | 4 +-
.../__memory/uninitialized_algorithms.h | 2 +-
libcxx/include/__memory/unique_ptr.h | 45 ++++++-------------
.../include/__type_traits/is_bounded_array.h | 4 +-
.../__type_traits/is_unbounded_array.h | 4 +-
5 files changed, 21 insertions(+), 38 deletions(-)
diff --git a/libcxx/include/__memory/shared_ptr.h b/libcxx/include/__memory/shared_ptr.h
index 00db96185be7c..5c4926457345f 100644
--- a/libcxx/include/__memory/shared_ptr.h
+++ b/libcxx/include/__memory/shared_ptr.h
@@ -944,7 +944,7 @@ struct __unbounded_array_control_block<_Tp[], _Alloc> : __shared_weak_count {
template <class _Array, class _Alloc, class... _Arg>
_LIBCPP_HIDE_FROM_ABI shared_ptr<_Array>
__allocate_shared_unbounded_array(const _Alloc& __a, size_t __n, _Arg&&... __arg) {
- static_assert(__libcpp_is_unbounded_array<_Array>::value);
+ static_assert(__is_unbounded_array_v<_Array>);
// We compute the number of bytes necessary to hold the control block and the
// array elements. Then, we allocate an array of properly-aligned dummy structs
// large enough to hold the control block and array. This allows shifting the
@@ -1021,7 +1021,7 @@ struct __bounded_array_control_block<_Tp[_Count], _Alloc> : __shared_weak_count
template <class _Array, class _Alloc, class... _Arg>
_LIBCPP_HIDE_FROM_ABI shared_ptr<_Array> __allocate_shared_bounded_array(const _Alloc& __a, _Arg&&... __arg) {
- static_assert(__libcpp_is_bounded_array<_Array>::value);
+ static_assert(__is_bounded_array_v<_Array>);
using _ControlBlock = __bounded_array_control_block<_Array, _Alloc>;
using _ControlBlockAlloc = __allocator_traits_rebind_t<_Alloc, _ControlBlock>;
diff --git a/libcxx/include/__memory/uninitialized_algorithms.h b/libcxx/include/__memory/uninitialized_algorithms.h
index 7475ef5cf85de..4374d371bcb8f 100644
--- a/libcxx/include/__memory/uninitialized_algorithms.h
+++ b/libcxx/include/__memory/uninitialized_algorithms.h
@@ -375,7 +375,7 @@ __allocator_destroy_multidimensional(_Alloc& __alloc, _BidirIter __first, _Bidir
return;
if constexpr (is_array_v<_ValueType>) {
- static_assert(!__libcpp_is_unbounded_array<_ValueType>::value,
+ static_assert(!__is_unbounded_array_v<_ValueType>,
"arrays of unbounded arrays don't exist, but if they did we would mess up here");
using _Element = remove_extent_t<_ValueType>;
diff --git a/libcxx/include/__memory/unique_ptr.h b/libcxx/include/__memory/unique_ptr.h
index 46d9405e31596..95f7b7f5d941d 100644
--- a/libcxx/include/__memory/unique_ptr.h
+++ b/libcxx/include/__memory/unique_ptr.h
@@ -26,6 +26,7 @@
#include <__type_traits/integral_constant.h>
#include <__type_traits/is_array.h>
#include <__type_traits/is_assignable.h>
+#include <__type_traits/is_bounded_array.h>
#include <__type_traits/is_constructible.h>
#include <__type_traits/is_convertible.h>
#include <__type_traits/is_function.h>
@@ -34,6 +35,7 @@
#include <__type_traits/is_same.h>
#include <__type_traits/is_swappable.h>
#include <__type_traits/is_trivially_relocatable.h>
+#include <__type_traits/is_unbounded_array.h>
#include <__type_traits/is_void.h>
#include <__type_traits/remove_extent.h>
#include <__type_traits/type_identity.h>
@@ -599,55 +601,36 @@ operator<=>(const unique_ptr<_T1, _D1>& __x, nullptr_t) {
#if _LIBCPP_STD_VER >= 14
-template <class _Tp>
-struct __unique_if {
- typedef unique_ptr<_Tp> __unique_single;
-};
-
-template <class _Tp>
-struct __unique_if<_Tp[]> {
- typedef unique_ptr<_Tp[]> __unique_array_unknown_bound;
-};
-
-template <class _Tp, size_t _Np>
-struct __unique_if<_Tp[_Np]> {
- typedef void __unique_array_known_bound;
-};
-
-template <class _Tp, class... _Args>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 typename __unique_if<_Tp>::__unique_single
-make_unique(_Args&&... __args) {
+template <class _Tp, class... _Args, enable_if_t<!is_array<_Tp>::value, int> = 0>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 unique_ptr<_Tp> make_unique(_Args&&... __args) {
return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...));
}
-template <class _Tp>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 typename __unique_if<_Tp>::__unique_array_unknown_bound
-make_unique(size_t __n) {
+template <class _Tp, enable_if_t<__is_unbounded_array_v<_Tp>, int> = 0>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 unique_ptr<_Tp> make_unique(size_t __n) {
typedef __remove_extent_t<_Tp> _Up;
return unique_ptr<_Tp>(new _Up[__n]());
}
-template <class _Tp, class... _Args>
-typename __unique_if<_Tp>::__unique_array_known_bound make_unique(_Args&&...) = delete;
+template <class _Tp, class... _Args, enable_if_t<__is_bounded_array_v<_Tp>, int> = 0>
+void make_unique(_Args&&...) = delete;
#endif // _LIBCPP_STD_VER >= 14
#if _LIBCPP_STD_VER >= 20
-template <class _Tp>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 typename __unique_if<_Tp>::__unique_single
-make_unique_for_overwrite() {
+template <class _Tp, enable_if_t<!is_array_v<_Tp>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 unique_ptr<_Tp> make_unique_for_overwrite() {
return unique_ptr<_Tp>(new _Tp);
}
-template <class _Tp>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 typename __unique_if<_Tp>::__unique_array_unknown_bound
-make_unique_for_overwrite(size_t __n) {
+template <class _Tp, enable_if_t<is_unbounded_array_v<_Tp>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 unique_ptr<_Tp> make_unique_for_overwrite(size_t __n) {
return unique_ptr<_Tp>(new __remove_extent_t<_Tp>[__n]);
}
-template <class _Tp, class... _Args>
-typename __unique_if<_Tp>::__unique_array_known_bound make_unique_for_overwrite(_Args&&...) = delete;
+template <class _Tp, class... _Args, enable_if_t<is_bounded_array_v<_Tp>, int> = 0>
+void make_unique_for_overwrite(_Args&&...) = delete;
#endif // _LIBCPP_STD_VER >= 20
diff --git a/libcxx/include/__type_traits/is_bounded_array.h b/libcxx/include/__type_traits/is_bounded_array.h
index 211403d638d08..93155d8c51499 100644
--- a/libcxx/include/__type_traits/is_bounded_array.h
+++ b/libcxx/include/__type_traits/is_bounded_array.h
@@ -20,9 +20,9 @@
_LIBCPP_BEGIN_NAMESPACE_STD
template <class>
-struct _LIBCPP_TEMPLATE_VIS __libcpp_is_bounded_array : false_type {};
+inline const bool __is_bounded_array_v = false;
template <class _Tp, size_t _Np>
-struct _LIBCPP_TEMPLATE_VIS __libcpp_is_bounded_array<_Tp[_Np]> : true_type {};
+inline const bool __is_bounded_array_v<_Tp[_Np]> = true;
#if _LIBCPP_STD_VER >= 20
diff --git a/libcxx/include/__type_traits/is_unbounded_array.h b/libcxx/include/__type_traits/is_unbounded_array.h
index d58bb09e10428..b0879476bd23e 100644
--- a/libcxx/include/__type_traits/is_unbounded_array.h
+++ b/libcxx/include/__type_traits/is_unbounded_array.h
@@ -19,9 +19,9 @@
_LIBCPP_BEGIN_NAMESPACE_STD
template <class>
-struct _LIBCPP_TEMPLATE_VIS __libcpp_is_unbounded_array : false_type {};
+inline const bool __is_unbounded_array_v = false;
template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS __libcpp_is_unbounded_array<_Tp[]> : true_type {};
+inline const bool __is_unbounded_array_v<_Tp[]> = true;
#if _LIBCPP_STD_VER >= 20
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