[libcxx-commits] [libcxx] [libc++] Optimize vector growing of trivially relocatable types (PR #76657)

[Amirreza Ashouri via libcxx-commits]

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+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include <__type_traits/is_trivially_relocatable.h>
+#include <memory>
+#include <string>
+
+#include "constexpr_char_traits.h"
+#include "test_allocator.h"
+
+static_assert(std::__libcpp_is_trivially_relocatable<char>::value);
+static_assert(std::__libcpp_is_trivially_relocatable<int>::value);
+static_assert(std::__libcpp_is_trivially_relocatable<double>::value);
+
+struct Empty {};
+static_assert(std::__libcpp_is_trivially_relocatable<Empty>::value);
+
+struct TriviallyCopyable {
+  char c;
+  int i;
+  Empty s;
+};
+static_assert(std::__libcpp_is_trivially_relocatable<TriviallyCopyable>::value);
+
+struct NotTriviallyCopyable {
+  NotTriviallyCopyable(const NotTriviallyCopyable&);
+  ~NotTriviallyCopyable();
+};
+static_assert(!std::__libcpp_is_trivially_relocatable<NotTriviallyCopyable>::value);
+
+struct MoveOnlyTriviallyCopyable {
+  MoveOnlyTriviallyCopyable(const MoveOnlyTriviallyCopyable&)            = delete;
+  MoveOnlyTriviallyCopyable& operator=(const MoveOnlyTriviallyCopyable&) = delete;
+  MoveOnlyTriviallyCopyable(MoveOnlyTriviallyCopyable&&)                 = default;
+  MoveOnlyTriviallyCopyable& operator=(MoveOnlyTriviallyCopyable&&)      = default;
+};
+static_assert(std::__libcpp_is_trivially_relocatable<MoveOnlyTriviallyCopyable>::value);
+
+// standard library types
+// ----------------------
+
+// basic_string
+struct MyChar {
+  char c;
+};
+template <class T>
+struct NotTriviallyRelocatableCharTraits : constexpr_char_traits<T> {
+  NotTriviallyRelocatableCharTraits(const NotTriviallyRelocatableCharTraits&);
+  NotTriviallyRelocatableCharTraits& operator=(const NotTriviallyRelocatableCharTraits&);
+  ~NotTriviallyRelocatableCharTraits();
+};
+
+static_assert(std::__libcpp_is_trivially_relocatable<
+              std::basic_string<char, std::char_traits<char>, std::allocator<char>>>::value);
+static_assert(std::__libcpp_is_trivially_relocatable<
+              std::basic_string<char, NotTriviallyRelocatableCharTraits<char>, std::allocator<char>>>::value);
+static_assert(std::__libcpp_is_trivially_relocatable<
+              std::basic_string<MyChar, constexpr_char_traits<MyChar>, std::allocator<MyChar>>>::value);
+static_assert(std::__libcpp_is_trivially_relocatable<
+              std::basic_string<MyChar, NotTriviallyRelocatableCharTraits<MyChar>, std::allocator<MyChar>>>::value);
+static_assert(!std::__libcpp_is_trivially_relocatable<
+              std::basic_string<char, std::char_traits<char>, test_allocator<char>>>::value);
+static_assert(!std::__libcpp_is_trivially_relocatable<
+              std::basic_string<MyChar, NotTriviallyRelocatableCharTraits<MyChar>, test_allocator<MyChar>>>::value);
+
+// unique_ptr
+struct NotTriviallyRelocatableDeleter {
+  NotTriviallyRelocatableDeleter(const NotTriviallyRelocatableDeleter&);
+  NotTriviallyRelocatableDeleter& operator=(const NotTriviallyRelocatableDeleter&);
+  ~NotTriviallyRelocatableDeleter();
+
+  template <class T>
+  void operator()(T*);
+};
+
+struct NotTriviallyRelocatablePointer {
+  struct pointer {
+    pointer(const pointer&);
+    pointer& operator=(const pointer&);
+    ~pointer();
+  };
+
+  template <class T>
+  void operator()(T*);
----------------
AMP999 wrote:

Could this use `min_pointer` instead?" (from libcxx/test/support/)

https://github.com/llvm/llvm-project/pull/76657