Drop most parts of thrust::allocator_traits (#7286)

* Drop most parts of `thrust::allocator_traits`

We already have standard conforming `cuda::std::allocator_traits`

Reuse those and only keep those pieces we require for legacy / systems support

* Avoidnarrowing warning with old gcc

* Drop `reference` and `const_reference` members

* Drop unused `is_allocator`

* Drop the deprecated `other` type alias

* Fully drop `detail::allocator_traits`

* Fix formatting

Author: miscco

libcudacxx/include/cuda/std/__memory/allocator_traits.h

@@ -326,11 +326,13 @@ struct _CCCL_TYPE_VISIBILITY_DEFAULT allocator_traits
   template <class _Tp>
   using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;
 
+  _CCCL_EXEC_CHECK_DISABLE
   [[nodiscard]] _CCCL_API inline _CCCL_CONSTEXPR_CXX20 static pointer allocate(allocator_type& __a, size_type __n)
   {
     return __a.allocate(__n);
   }
 
+  _CCCL_EXEC_CHECK_DISABLE
   [[nodiscard]] _CCCL_API inline _CCCL_CONSTEXPR_CXX20 static pointer
   allocate(allocator_type& __a, size_type __n, [[maybe_unused]] const_void_pointer __hint)
   {
@@ -344,11 +346,13 @@ struct _CCCL_TYPE_VISIBILITY_DEFAULT allocator_traits
     }
   }
 
+  _CCCL_EXEC_CHECK_DISABLE
   _CCCL_API inline _CCCL_CONSTEXPR_CXX20 static void deallocate(allocator_type& __a, pointer __p, size_type __n) noexcept
   {
     __a.deallocate(__p, __n);
   }
 
+  _CCCL_EXEC_CHECK_DISABLE
   template <class _Tp, class... _Args>
   _CCCL_API inline _CCCL_CONSTEXPR_CXX20 static void
   construct([[maybe_unused]] allocator_type& __a, _Tp* __p, _Args&&... __args)
@@ -359,10 +363,15 @@ struct _CCCL_TYPE_VISIBILITY_DEFAULT allocator_traits
     }
     else
     {
+#if _CCCL_COMPILER(GCC, <, 8) // GCC7 and below fail with narrowing conversions
+      ::new (const_cast<void*>(static_cast<const volatile void*>(__p))) _Tp(::cuda::std::forward<_Args>(__args)...);
+#else // ^^^ _CCCL_COMPILER(GCC, <, 8) ^^^ / vvv _CCCL_COMPILER(GCC, >=, 8) vvv
       ::cuda::std::__construct_at(__p, ::cuda::std::forward<_Args>(__args)...);
+#endif // _CCCL_COMPILER(GCC, >=, 8)
     }
   }
 
+  _CCCL_EXEC_CHECK_DISABLE
   template <class _Tp>
   _CCCL_API inline _CCCL_CONSTEXPR_CXX20 static void destroy([[maybe_unused]] allocator_type& __a, _Tp* __p) noexcept
   {
@@ -376,6 +385,7 @@ struct _CCCL_TYPE_VISIBILITY_DEFAULT allocator_traits
     }
   }
 
+  _CCCL_EXEC_CHECK_DISABLE
   _CCCL_API inline _CCCL_CONSTEXPR_CXX20 static size_type max_size([[maybe_unused]] const allocator_type& __a) noexcept
   {
     if constexpr (__has_max_size<const _Alloc>)
@@ -388,6 +398,7 @@ struct _CCCL_TYPE_VISIBILITY_DEFAULT allocator_traits
     }
   }
 
+  _CCCL_EXEC_CHECK_DISABLE
   _CCCL_API inline _CCCL_CONSTEXPR_CXX20 static allocator_type
   select_on_container_copy_construction(const allocator_type& __a)
   {
@@ -401,6 +412,7 @@ struct _CCCL_TYPE_VISIBILITY_DEFAULT allocator_traits
     }
   }
 
+  _CCCL_EXEC_CHECK_DISABLE
   template <class _Ptr>
   _CCCL_API inline static void
   __construct_forward_with_exception_guarantees(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __begin2)

thrust/testing/allocator.cu

@@ -186,15 +186,14 @@ DECLARE_VARIABLE_UNITTEST(TestAllocatorMinimal);
 void TestAllocatorTraitsRebind()
 {
   ASSERT_EQUAL(
-    (::cuda::std::is_same<typename thrust::detail::allocator_traits<
-                            thrust::device_malloc_allocator<int>>::template rebind_traits<float>::other,
-                          typename thrust::detail::allocator_traits<thrust::device_malloc_allocator<float>>>::value),
+    (::cuda::std::is_same<
+      typename cuda::std::allocator_traits<thrust::device_malloc_allocator<int>>::template rebind_traits<float>,
+      typename cuda::std::allocator_traits<thrust::device_malloc_allocator<float>>>::value),
     true);
 
   ASSERT_EQUAL(
-    (::cuda::std::is_same<
-      typename thrust::detail::allocator_traits<my_minimal_allocator<int>>::template rebind_traits<float>::other,
-      typename thrust::detail::allocator_traits<my_minimal_allocator<float>>>::value),
+    (::cuda::std::is_same<typename cuda::std::allocator_traits<my_minimal_allocator<int>>::template rebind_traits<float>,
+                          typename cuda::std::allocator_traits<my_minimal_allocator<float>>>::value),
     true);
 }
 DECLARE_UNITTEST(TestAllocatorTraitsRebind);
@@ -203,24 +202,24 @@ void TestAllocatorTraitsRebindCpp11()
 {
   ASSERT_EQUAL(
     (::cuda::std::is_same<
-      typename thrust::detail::allocator_traits<thrust::device_malloc_allocator<int>>::template rebind_alloc<float>,
+      typename cuda::std::allocator_traits<thrust::device_malloc_allocator<int>>::template rebind_alloc<float>,
       thrust::device_malloc_allocator<float>>::value),
     true);
 
-  ASSERT_EQUAL((::cuda::std::is_same<
-                 typename thrust::detail::allocator_traits<my_minimal_allocator<int>>::template rebind_alloc<float>,
-                 my_minimal_allocator<float>>::value),
-               true);
+  ASSERT_EQUAL(
+    (::cuda::std::is_same<typename cuda::std::allocator_traits<my_minimal_allocator<int>>::template rebind_alloc<float>,
+                          my_minimal_allocator<float>>::value),
+    true);
 
   ASSERT_EQUAL(
     (::cuda::std::is_same<
-      typename thrust::detail::allocator_traits<thrust::device_malloc_allocator<int>>::template rebind_traits<float>,
-      typename thrust::detail::allocator_traits<thrust::device_malloc_allocator<float>>>::value),
+      typename cuda::std::allocator_traits<thrust::device_malloc_allocator<int>>::template rebind_traits<float>,
+      typename cuda::std::allocator_traits<thrust::device_malloc_allocator<float>>>::value),
     true);
 
-  ASSERT_EQUAL((::cuda::std::is_same<
-                 typename thrust::detail::allocator_traits<my_minimal_allocator<int>>::template rebind_traits<float>,
-                 typename thrust::detail::allocator_traits<my_minimal_allocator<float>>>::value),
-               true);
+  ASSERT_EQUAL(
+    (::cuda::std::is_same<typename cuda::std::allocator_traits<my_minimal_allocator<int>>::template rebind_traits<float>,
+                          typename cuda::std::allocator_traits<my_minimal_allocator<float>>>::value),
+    true);
 }
 DECLARE_UNITTEST(TestAllocatorTraitsRebindCpp11);

thrust/testing/binary_search_vector.cu

@@ -1,5 +1,5 @@
 #include <thrust/binary_search.h>
-#include <thrust/detail/allocator/allocator_traits.h>
+#include <thrust/detail/allocator/allocator_system.h>
 #include <thrust/iterator/discard_iterator.h>
 #include <thrust/iterator/retag.h>
 #include <thrust/sequence.h>
@@ -16,7 +16,7 @@ template <class ExampleVector, typename NewType>
 struct vector_like
 {
   using alloc        = typename ExampleVector::allocator_type;
-  using alloc_traits = typename thrust::detail::allocator_traits<alloc>;
+  using alloc_traits = typename cuda::std::allocator_traits<alloc>;
   using new_alloc    = typename alloc_traits::template rebind_alloc<NewType>;
   using type         = thrust::detail::vector_base<NewType, new_alloc>;
 };

thrust/testing/binary_search_vector_descending.cu

@@ -1,5 +1,5 @@
 #include <thrust/binary_search.h>
-#include <thrust/detail/allocator/allocator_traits.h>
+#include <thrust/detail/allocator/allocator_system.h>
 #include <thrust/functional.h>
 #include <thrust/sequence.h>
 #include <thrust/sort.h>
@@ -15,7 +15,7 @@ template <class ExampleVector, typename NewType>
 struct vector_like
 {
   using alloc        = typename ExampleVector::allocator_type;
-  using alloc_traits = typename thrust::detail::allocator_traits<alloc>;
+  using alloc_traits = typename cuda::std::allocator_traits<alloc>;
   using new_alloc    = typename alloc_traits::template rebind_alloc<NewType>;
   using type         = thrust::detail::vector_base<NewType, new_alloc>;
 };

thrust/testing/caching_allocator.cu

@@ -7,7 +7,7 @@
 template <typename Allocator>
 void test_implementation(Allocator alloc)
 {
-  using Traits = typename thrust::detail::allocator_traits<Allocator>;
+  using Traits = typename cuda::std::allocator_traits<Allocator>;
   using Ptr    = typename Allocator::pointer;
 
   Ptr p = Traits::allocate(alloc, 123);

thrust/testing/catch2_test_functional_placeholders_logical.cu

@@ -1,4 +1,4 @@
-#include <thrust/detail/allocator/allocator_traits.h>
+#include <thrust/detail/allocator/allocator_system.h>
 #include <thrust/functional.h>
 #include <thrust/transform.h>
 
@@ -13,7 +13,7 @@ struct rebind_vector;
 template <typename T, typename U, typename Allocator>
 struct rebind_vector<thrust::host_vector<T, Allocator>, U>
 {
-  using type = thrust::host_vector<U, typename thrust::detail::allocator_traits<Allocator>::template rebind_alloc<U>>;
+  using type = thrust::host_vector<U, typename cuda::std::allocator_traits<Allocator>::template rebind_alloc<U>>;
 };
 
 template <typename T, typename U, typename Allocator>

thrust/testing/functional_placeholders_bitwise.cu

@@ -1,4 +1,4 @@
-#include <thrust/detail/allocator/allocator_traits.h>
+#include <thrust/detail/allocator/allocator_system.h>
 #include <thrust/functional.h>
 #include <thrust/iterator/constant_iterator.h>
 #include <thrust/transform.h>
@@ -13,7 +13,7 @@ struct rebind_vector;
 template <typename T, typename U, typename Allocator>
 struct rebind_vector<thrust::host_vector<T, Allocator>, U>
 {
-  using alloc_traits = typename thrust::detail::allocator_traits<Allocator>;
+  using alloc_traits = typename cuda::std::allocator_traits<Allocator>;
   using new_alloc    = typename alloc_traits::template rebind_alloc<U>;
   using type         = thrust::host_vector<U, new_alloc>;
 };

thrust/testing/functional_placeholders_relational.cu

@@ -1,4 +1,4 @@
-#include <thrust/detail/allocator/allocator_traits.h>
+#include <thrust/detail/allocator/allocator_system.h>
 #include <thrust/functional.h>
 #include <thrust/transform.h>
 
@@ -12,7 +12,7 @@ struct rebind_vector;
 template <typename T, typename U, typename Allocator>
 struct rebind_vector<thrust::host_vector<T, Allocator>, U>
 {
-  using alloc_traits = typename thrust::detail::allocator_traits<Allocator>;
+  using alloc_traits = typename cuda::std::allocator_traits<Allocator>;
   using new_alloc    = typename alloc_traits::template rebind_alloc<U>;
   using type         = thrust::host_vector<U, new_alloc>;
 };

thrust/testing/vector_allocators.cu

@@ -8,7 +8,7 @@
 template <typename BaseAlloc, bool PropagateOnSwap>
 class stateful_allocator : public BaseAlloc
 {
-  using base_traits = thrust::detail::allocator_traits<BaseAlloc>;
+  using base_traits = cuda::std::allocator_traits<BaseAlloc>;
 
 public:
   stateful_allocator(int i)
@@ -47,8 +47,8 @@ public:
 
   using pointer         = typename base_traits::pointer;
   using const_pointer   = typename base_traits::const_pointer;
-  using reference       = typename base_traits::reference;
-  using const_reference = typename base_traits::const_reference;
+  using reference       = typename cuda::std::iterator_traits<pointer>::reference;
+  using const_reference = typename cuda::std::iterator_traits<const_pointer>::reference;
 
   pointer allocate(std::size_t size)
   {
@@ -177,8 +177,7 @@ template <typename Vector>
 void TestVectorAllocatorPropagateOnCopyAssignment()
 {
   ASSERT_EQUAL(
-    thrust::detail::allocator_traits<typename Vector::allocator_type>::propagate_on_container_copy_assignment::value,
-    true);
+    cuda::std::allocator_traits<typename Vector::allocator_type>::propagate_on_container_copy_assignment::value, true);
 
   using Alloc = typename Vector::allocator_type;
   Alloc alloc1(1);
@@ -211,8 +210,7 @@ void TestVectorAllocatorPropagateOnMoveAssignment()
 {
   using Alloc = typename Vector::allocator_type;
   ASSERT_EQUAL(
-    thrust::detail::allocator_traits<typename Vector::allocator_type>::propagate_on_container_copy_assignment::value,
-    true);
+    cuda::std::allocator_traits<typename Vector::allocator_type>::propagate_on_container_copy_assignment::value, true);
 
   using Alloc = typename Vector::allocator_type;
   Alloc alloc1(1);

thrust/thrust/allocate_unique.h

@@ -14,12 +14,12 @@
 #elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
 #  pragma system_header
 #endif // no system header
-#include <thrust/detail/allocator/allocator_traits.h>
 #include <thrust/detail/memory_algorithms.h>
 #include <thrust/detail/raw_pointer_cast.h>
 #include <thrust/detail/type_deduction.h>
 
 #include <cuda/std/__cccl/memory_wrapper.h>
+#include <cuda/std/__memory/allocator_traits.h>
 #include <cuda/std/__type_traits/remove_cvref.h>
 #include <cuda/std/__utility/move.h>
 #include <cuda/std/__utility/swap.h>
@@ -35,7 +35,7 @@ struct allocator_delete final
 {
   using allocator_type =
     typename std::remove_cv<typename std::remove_reference<Allocator>::type>::type::template rebind<T>::other;
-  using pointer = typename detail::allocator_traits<allocator_type>::pointer;
+  using pointer = typename ::cuda::std::allocator_traits<allocator_type>::pointer;
 
   template <typename UAllocator>
   allocator_delete(UAllocator&& other) noexcept
@@ -66,7 +66,7 @@ struct allocator_delete final
 
   void operator()(pointer p)
   {
-    using traits = detail::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>;
+    using traits = ::cuda::std::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>;
     typename traits::allocator_type alloc_T(alloc_);
 
     if (nullptr != detail::pointer_traits<pointer>::get(p))
@@ -106,7 +106,7 @@ struct array_allocator_delete final
 {
   using allocator_type =
     typename std::remove_cv<typename std::remove_reference<Allocator>::type>::type::template rebind<T>::other;
-  using pointer = typename detail::allocator_traits<allocator_type>::pointer;
+  using pointer = typename ::cuda::std::allocator_traits<allocator_type>::pointer;
 
   template <typename UAllocator>
   array_allocator_delete(UAllocator&& other, std::size_t n) noexcept
@@ -142,7 +142,7 @@ struct array_allocator_delete final
 
   void operator()(pointer p)
   {
-    using traits = detail::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>;
+    using traits = ::cuda::std::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>;
     typename traits::allocator_type alloc_T(get_allocator());
     if (nullptr != detail::pointer_traits<pointer>::get(p))
     {
@@ -204,11 +204,12 @@ template <typename T, typename Allocator, typename... Args>
 _CCCL_HOST
 std::unique_ptr<T,
                 allocator_delete<T,
-                                 typename detail::allocator_traits<
+                                 typename ::cuda::std::allocator_traits<
                                    ::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>::allocator_type>>
 allocate_unique(Allocator const& alloc, Args&&... args)
 {
-  using traits = typename detail::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>;
+  using traits =
+    typename ::cuda::std::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>;
 
   typename traits::allocator_type alloc_T(alloc);
 
@@ -228,12 +229,13 @@ allocate_unique(Allocator const& alloc, Args&&... args)
 template <typename T, typename Allocator>
 _CCCL_HOST std::unique_ptr<
   T,
-  uninitialized_allocator_delete<
-    T,
-    typename detail::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>::allocator_type>>
+  uninitialized_allocator_delete<T,
+                                 typename ::cuda::std::allocator_traits<
+                                   ::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>::allocator_type>>
 uninitialized_allocate_unique(Allocator const& alloc)
 {
-  using traits = typename detail::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>;
+  using traits =
+    typename ::cuda::std::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>;
 
   typename traits::allocator_type alloc_T(alloc);
 
@@ -253,11 +255,12 @@ template <typename T, typename Allocator, typename Size, typename... Args>
 _CCCL_HOST std::unique_ptr<
   T[],
   array_allocator_delete<T,
-                         typename detail::allocator_traits<typename std::remove_cv<typename std::remove_reference<
+                         typename ::cuda::std::allocator_traits<typename std::remove_cv<typename std::remove_reference<
                            Allocator>::type>::type>::template rebind_traits<T>::allocator_type>>
 allocate_unique_n(Allocator const& alloc, Size n, Args&&... args)
 {
-  using traits = typename detail::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>;
+  using traits =
+    typename ::cuda::std::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>;
 
   typename traits::allocator_type alloc_T(alloc);
 
@@ -275,14 +278,15 @@ allocate_unique_n(Allocator const& alloc, Size n, Args&&... args)
 //! Creates a \p std::unique_ptr holding storage for an array of objects of type \p T without constructing them, using
 //! \p alloc as the allocator.
 template <typename T, typename Allocator, typename Size>
-_CCCL_HOST std::unique_ptr<
-  T[],
-  uninitialized_array_allocator_delete<
-    T,
-    typename detail::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>::allocator_type>>
+_CCCL_HOST
+std::unique_ptr<T[],
+                uninitialized_array_allocator_delete<T,
+                                                     typename ::cuda::std::allocator_traits<::cuda::std::remove_cvref_t<
+                                                       Allocator>>::template rebind_traits<T>::allocator_type>>
 uninitialized_allocate_unique_n(Allocator const& alloc, Size n)
 {
-  using traits = typename detail::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>;
+  using traits =
+    typename ::cuda::std::allocator_traits<::cuda::std::remove_cvref_t<Allocator>>::template rebind_traits<T>;
 
   typename traits::allocator_type alloc_T(alloc);