<xmemory>: Remove std::allocator<void> full specialization (micro…

…soft#2726) Co-authored-by: Casey Carter <[email protected]> Co-authored-by: Stephan T. Lavavej <[email protected]>
fsb4000 · Aug 13, 2022 · 08705f3 · 08705f3
1 parent 2c64b50
commit 08705f3
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Showing 5 changed files with 83 additions and 7 deletions.
diff --git a/stl/inc/xmemory b/stl/inc/xmemory
@@ -833,6 +833,7 @@ public:
     }
 
     _NODISCARD _CONSTEXPR20 __declspec(allocator) _Ty* allocate(_CRT_GUARDOVERFLOW const size_t _Count) {
+        static_assert(sizeof(value_type) > 0, "value_type must be complete before calling allocate.");
         return static_cast<_Ty*>(_Allocate<_New_alignof<_Ty>>(_Get_size_of_n<sizeof(_Ty)>(_Count)));
     }
 
@@ -866,28 +867,30 @@ public:
     static constexpr size_t _Minimum_allocation_alignment = _Asan_granularity;
 };
 
+#if _HAS_DEPRECATED_ALLOCATOR_VOID || _HAS_DEPRECATED_ALLOCATOR_MEMBERS
 template <>
 class allocator<void> {
 public:
     using value_type = void;
 #if _HAS_DEPRECATED_ALLOCATOR_MEMBERS
     _CXX17_DEPRECATE_OLD_ALLOCATOR_MEMBERS typedef void* pointer;
     _CXX17_DEPRECATE_OLD_ALLOCATOR_MEMBERS typedef const void* const_pointer;
+
+    template <class _Other>
+    struct _CXX17_DEPRECATE_OLD_ALLOCATOR_MEMBERS rebind {
+        using other = allocator<_Other>;
+    };
 #endif // _HAS_DEPRECATED_ALLOCATOR_MEMBERS
 
+#if _HAS_CXX20
     using size_type       = size_t;
     using difference_type = ptrdiff_t;
 
     using propagate_on_container_move_assignment           = true_type;
     using is_always_equal _CXX20_DEPRECATE_IS_ALWAYS_EQUAL = true_type;
-
-#if _HAS_DEPRECATED_ALLOCATOR_MEMBERS
-    template <class _Other>
-    struct _CXX17_DEPRECATE_OLD_ALLOCATOR_MEMBERS rebind {
-        using other = allocator<_Other>;
-    };
-#endif // _HAS_DEPRECATED_ALLOCATOR_MEMBERS
+#endif // _HAS_CXX20
 };
+#endif // _HAS_DEPRECATED_ALLOCATOR_VOID || _HAS_DEPRECATED_ALLOCATOR_MEMBERS
 
 template <class _Ty, class _Other>
 _NODISCARD _CONSTEXPR20 bool operator==(const allocator<_Ty>&, const allocator<_Other>&) noexcept {

diff --git a/stl/inc/yvals_core.h b/stl/inc/yvals_core.h
@@ -1197,6 +1197,10 @@
 #define _HAS_DEPRECATED_ALLOCATOR_MEMBERS (_HAS_FEATURES_REMOVED_IN_CXX20)
 #endif // _HAS_DEPRECATED_ALLOCATOR_MEMBERS
 
+#ifndef _HAS_DEPRECATED_ALLOCATOR_VOID
+#define _HAS_DEPRECATED_ALLOCATOR_VOID (_HAS_FEATURES_REMOVED_IN_CXX20)
+#endif // _HAS_DEPRECATED_ALLOCATOR_VOID
+
 #ifndef _HAS_DEPRECATED_IS_LITERAL_TYPE
 #define _HAS_DEPRECATED_IS_LITERAL_TYPE (_HAS_FEATURES_REMOVED_IN_CXX20)
 #endif // _HAS_DEPRECATED_IS_LITERAL_TYPE

diff --git a/tests/std/test.lst b/tests/std/test.lst
@@ -164,6 +164,7 @@ tests\GH_000431_lex_compare_family
 tests\GH_000431_lex_compare_memcmp_classify
 tests\GH_000442_random_subtract_with_carry_engine_io
 tests\GH_000457_system_error_message
+tests\GH_000527_remove_allocator_void
 tests\GH_000545_include_compare
 tests\GH_000625_vector_bool_optimization
 tests\GH_000685_condition_variable_any

diff --git a/tests/std/tests/GH_000527_remove_allocator_void/env.lst b/tests/std/tests/GH_000527_remove_allocator_void/env.lst
@@ -0,0 +1,4 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+RUNALL_INCLUDE ..\usual_matrix.lst
diff --git a/tests/std/tests/GH_000527_remove_allocator_void/test.compile.pass.cpp b/tests/std/tests/GH_000527_remove_allocator_void/test.compile.pass.cpp
@@ -0,0 +1,64 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#define _SILENCE_CXX20_IS_ALWAYS_EQUAL_DEPRECATION_WARNING
+
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+
+using namespace std;
+
+template <class T, class = void>
+constexpr bool has_member_size_type = false;
+
+template <class T>
+constexpr bool has_member_size_type<T, void_t<typename T::size_type>> = true;
+
+template <class T, class = void>
+constexpr bool has_member_difference_type = false;
+
+template <class T>
+constexpr bool has_member_difference_type<T, void_t<typename T::difference_type>> = true;
+
+template <class T, class = void>
+constexpr bool has_member_pocma = false;
+
+template <class T>
+constexpr bool has_member_pocma<T, void_t<typename T::propagate_on_container_move_assignment>> = true;
+
+template <class T, class = void>
+constexpr bool has_member_is_always_equal = false;
+
+template <class T>
+constexpr bool has_member_is_always_equal<T, void_t<typename T::is_always_equal>> = true;
+
+template <class T, class = void>
+constexpr bool can_allocate = false;
+
+template <class T>
+constexpr bool can_allocate<T, void_t<decltype(declval<T&>().allocate(size_t{}))>> = true;
+
+STATIC_ASSERT(has_member_size_type<allocator<int>>);
+STATIC_ASSERT(has_member_difference_type<allocator<int>>);
+STATIC_ASSERT(has_member_pocma<allocator<int>>);
+STATIC_ASSERT(has_member_is_always_equal<allocator<int>>);
+STATIC_ASSERT(can_allocate<allocator<int>>);
+STATIC_ASSERT(is_convertible_v<allocator<void>, allocator<int>>);
+
+#if _HAS_CXX20
+constexpr bool has_cxx20 = true;
+#else
+constexpr bool has_cxx20 = false;
+#endif
+
+STATIC_ASSERT(has_cxx20 == has_member_size_type<allocator<void>>);
+STATIC_ASSERT(has_cxx20 == has_member_difference_type<allocator<void>>);
+STATIC_ASSERT(has_cxx20 == has_member_pocma<allocator<void>>);
+STATIC_ASSERT(has_cxx20 == has_member_is_always_equal<allocator<void>>);
+STATIC_ASSERT(has_cxx20 == can_allocate<allocator<void>>);
+STATIC_ASSERT(has_cxx20 == is_convertible_v<allocator<int>, allocator<void>>);
+
+int main() {} // COMPILE-ONLY