Add move semantics to ViewCtorProp and ViewCtorProp<void,std::string>

core/src/View/Kokkos_ViewCtor.hpp

@@ -106,14 +106,12 @@ struct ViewCtorProp<std::enable_if_t<std::is_same_v<P, AllowPadding_t> ||
 /* Map input label type to std::string */
 template <typename Label>
 struct ViewCtorProp<std::enable_if_t<is_view_label<Label>::value>, Label> {
-  ViewCtorProp()                                = default;
-  ViewCtorProp(const ViewCtorProp &)            = default;
-  ViewCtorProp &operator=(const ViewCtorProp &) = default;
+  ViewCtorProp() = default;
 
   using type = std::string;
 
   ViewCtorProp(const type &arg) : value(arg) {}
-  ViewCtorProp(type &&arg) : value(arg) {}
+  ViewCtorProp(type &&arg) : value(std::move(arg)) {}
 
   type value;
 };
@@ -213,11 +211,12 @@ struct ViewCtorProp : public ViewCtorProp<void, P>... {
   using execution_space = typename var_execution_space::type;
   using pointer_type    = typename var_pointer::type;
 
-  /*  Copy from a matching argument list.
-   *  Requires  std::is_same< P , ViewCtorProp< void , Args >::value ...
-   */
+  ViewCtorProp() = default;
+
+  //! Construct from a matching argument list.
   template <typename... Args>
-  inline ViewCtorProp(Args const &...args) : ViewCtorProp<void, P>(args)... {}
+  ViewCtorProp(Args &&...args)
+      : ViewCtorProp<void, P>(std::forward<Args>(args))... {}
 
   template <typename... Args>
   KOKKOS_FUNCTION ViewCtorProp(pointer_type arg0, Args const &...args)
@@ -236,11 +235,12 @@ struct ViewCtorProp : public ViewCtorProp<void, P>... {
   template <typename... Args>
   ViewCtorProp(view_ctor_prop_args<Args...> const &arg)
       : view_ctor_prop_base<Args>(
-            static_cast<view_ctor_prop_base<Args> const &>(arg))... {
-    // Suppress an unused argument warning that (at least at one point) would
-    // show up if sizeof...(Args) == 0
-    (void)arg;
-  }
+            static_cast<view_ctor_prop_base<Args> const &>(arg))... {}
+
+  template <typename... Args>
+  ViewCtorProp(view_ctor_prop_args<Args...> &&arg)
+      : view_ctor_prop_base<Args>(
+            static_cast<view_ctor_prop_base<Args> &&>(arg))... {}
 };
 
 #if !defined(KOKKOS_COMPILER_MSVC) || !defined(KOKKOS_COMPILER_NVCC)

core/unit_test/CMakeLists.txt

@@ -282,6 +282,7 @@ foreach(Tag Threads;Serial;OpenMP;Cuda;HPX;OpenMPTarget;OpenACC;HIP;SYCL)
       ViewCopy_b
       ViewCopy_c
       ViewCtorDimMatch
+      ViewCtorProp
       ViewEmptyRuntimeUnmanaged
       ViewHooks
       ViewLayoutStrideAssignment

core/unit_test/TestViewCtorProp.hpp

@@ -0,0 +1,136 @@
+//@HEADER
+// ************************************************************************
+//
+//                        Kokkos v. 4.0
+//       Copyright (2022) National Technology & Engineering
+//               Solutions of Sandia, LLC (NTESS).
+//
+// Under the terms of Contract DE-NA0003525 with NTESS,
+// the U.S. Government retains certain rights in this software.
+//
+// Part of Kokkos, under the Apache License v2.0 with LLVM Exceptions.
+// See https://kokkos.org/LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//@HEADER
+
+#include <gtest/gtest.h>
+
+#include <Kokkos_Core.hpp>
+
+namespace Test {
+
+// Check Kokkos::Impl::is_view_label.
+TEST(TEST_CATEGORY, is_view_label) {
+  static_assert(Kokkos::Impl::is_view_label<std::string>::value);
+
+  constexpr unsigned N = 3;
+  static_assert(Kokkos::Impl::is_view_label<const char[N]>::value);
+  static_assert(Kokkos::Impl::is_view_label<char[N]>::value);
+
+  static_assert(!Kokkos::Impl::is_view_label<char*>::value);
+}
+
+// Check traits of Kokkos::Impl::ViewCtorProp<void, std::string>.
+TEST(TEST_CATEGORY, vcp_label_base_traits) {
+  using vcp_label_base_t = Kokkos::Impl::ViewCtorProp<void, std::string>;
+
+  static_assert(std::is_default_constructible_v<vcp_label_base_t>);
+  static_assert(std::is_copy_constructible_v<vcp_label_base_t>);
+  static_assert(std::is_copy_assignable_v<vcp_label_base_t>);
+  static_assert(std::is_move_constructible_v<vcp_label_base_t>);
+  static_assert(std::is_move_assignable_v<vcp_label_base_t>);
+
+  static_assert(std::is_same_v<typename vcp_label_base_t::type, std::string>);
+
+  static_assert(std::is_constructible_v<vcp_label_base_t, std::string>);
+  static_assert(std::is_constructible_v<vcp_label_base_t, const std::string&>);
+  static_assert(std::is_constructible_v<vcp_label_base_t, std::string&&>);
+
+  constexpr unsigned N = 3;
+  static_assert(std::is_constructible_v<vcp_label_base_t, const char[N]>);
+  static_assert(std::is_constructible_v<vcp_label_base_t, char*>);
+}
+
+// Check traits of Kokkos::Impl::ViewCtorProp<std::string>.
+TEST(TEST_CATEGORY, vcp_label_traits) {
+  using vcp_label_base_t = Kokkos::Impl::ViewCtorProp<void, std::string>;
+  using vcp_label_t      = Kokkos::Impl::ViewCtorProp<std::string>;
+
+  static_assert(std::is_base_of_v<vcp_label_base_t, vcp_label_t>);
+
+  static_assert(vcp_label_t::has_label);
+
+  static_assert(std::is_default_constructible_v<vcp_label_t>);
+  static_assert(std::is_copy_constructible_v<vcp_label_t>);
+  static_assert(std::is_copy_assignable_v<vcp_label_t>);
+  static_assert(std::is_move_constructible_v<vcp_label_t>);
+  static_assert(std::is_move_assignable_v<vcp_label_t>);
+
+  static_assert(std::is_constructible_v<vcp_label_t, std::string>);
+  static_assert(std::is_constructible_v<vcp_label_t, const std::string&>);
+  static_assert(std::is_constructible_v<vcp_label_t, std::string&&>);
+
+  constexpr unsigned N = 3;
+  static_assert(std::is_constructible_v<vcp_label_t, const char[N]>);
+  static_assert(std::is_constructible_v<vcp_label_t, char*>);
+}
+
+// Check functions related to Kokkos::Impl::ViewCtorProp<std::string>.
+TEST(TEST_CATEGORY, vcp_label_fcns) {
+  using vcp_label_t = Kokkos::Impl::ViewCtorProp<std::string>;
+
+  // Check that the user-declared constructor can move.
+  std::string label("our label");
+
+  vcp_label_t prop(std::move(label));
+
+  ASSERT_TRUE(label.empty());
+  ASSERT_EQ(Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop),
+            "our label");
+
+  // Check the user-declared copy onstructor.
+  vcp_label_t prop_copy_constr(prop);
+  ASSERT_EQ(Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop),
+            "our label");
+  ASSERT_EQ(
+      Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop_copy_constr),
+      "our label");
+
+  // Check the compiler-generated copy assignment operator.
+  vcp_label_t prop_copy_asgmt;
+  prop_copy_asgmt = prop;
+  ASSERT_EQ(Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop),
+            "our label");
+  ASSERT_EQ(Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop_copy_asgmt),
+            "our label");
+
+  // Check the user-declared move constructor.
+  vcp_label_t prop_move_constr(std::move(prop));
+  ASSERT_TRUE(Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop).empty());
+  ASSERT_EQ(
+      Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop_move_constr),
+      "our label");
+
+  // Check the compiler-generated move assignment operator.
+  vcp_label_t prop_move_asgmt;
+  prop_move_asgmt = std::move(prop_copy_asgmt);
+  ASSERT_TRUE(
+      Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop_copy_asgmt)
+          .empty());
+  ASSERT_EQ(Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop_move_asgmt),
+            "our label");
+
+  // Check Kokkos::Impl::with_properties_if_unset.
+  auto prop_empty = Kokkos::view_alloc();
+
+  static_assert(!decltype(prop_empty)::has_label);
+
+  const auto prop_with_label = Kokkos::Impl::with_properties_if_unset(
+      prop_empty, std::string("our label"));
+  static_assert(decltype(prop_with_label)::has_label);
+  ASSERT_EQ(Kokkos::Impl::get_property<Kokkos::Impl::LabelTag>(prop_with_label),
+            "our label");
+}
+
+}  // namespace Test