8250652: Add logical operations on types

Add stand-ins for C++17 logical operations on types.

Reviewed-by: eosterlund, tschatzl

Author: Kim Barrett

src/hotspot/share/metaprogramming/logical.hpp

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_METAPROGRAMMING_LOGICAL_HPP
+#define SHARE_METAPROGRAMMING_LOGICAL_HPP
+
+// Stand-ins for C++17 logical operations on types.
+
+#include <type_traits>
+
+// Stand-in for C++17 std::bool_constant<value>.
+template<bool Value>
+using BoolConstant = std::integral_constant<bool, Value>;
+
+// Stand-in for C++17 std::conjunction<T...>
+template<typename... T>
+struct Conjunction : public std::true_type {};
+
+template<typename T1>
+struct Conjunction<T1> : public T1 {};
+
+template<typename T1, typename... T>
+struct Conjunction<T1, T...> :
+  public std::conditional_t<bool(T1::value), Conjunction<T...>, T1>
+{};
+
+// Stand-in for C++17 std::disjunction<T...>.
+template<typename... T>
+struct Disjunction : public std::false_type {};
+
+template<typename T1>
+struct Disjunction<T1> : public T1 {};
+
+template<typename T1, typename... T>
+struct Disjunction<T1, T...> :
+  public std::conditional_t<bool(T1::value), T1, Disjunction<T...>>
+{};
+
+// Stand-in for C++17 std::negation<T>.
+template<typename T>
+using Negation = BoolConstant<!bool(T::value)>;
+
+#endif // SHARE_METAPROGRAMMING_LOGICAL_HPP

test/hotspot/gtest/metaprogramming/test_logical.cpp

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "metaprogramming/logical.hpp"
+#include <type_traits>
+
+class TestBoolConstant {
+  static_assert(BoolConstant<true>::value, "true");
+  static_assert(!BoolConstant<false>::value, "false");
+};
+
+class TestConjunction {
+  class A : public std::true_type {};
+  class B : public std::true_type {};
+  class C : public std::false_type {};
+  class D : public std::false_type {};
+
+  static_assert(Conjunction<>::value, "nullary value");
+
+  static_assert(Conjunction<A>::value, "true value");
+  static_assert(std::is_base_of<A, Conjunction<A>>::value, "true type");
+
+  static_assert(!Conjunction<C>::value, "false value");
+  static_assert(std::is_base_of<C, Conjunction<C>>::value, "false type");
+
+  static_assert(Conjunction<A, B>::value, "true/true value");
+  static_assert(std::is_base_of<B, Conjunction<A, B>>::value, "true/true type");
+
+  static_assert(!Conjunction<A, C>::value, "true/false value");
+  static_assert(std::is_base_of<C, Conjunction<A, C>>::value, "true/false type");
+
+  static_assert(!Conjunction<C, A>::value, "false/true value");
+  static_assert(std::is_base_of<C, Conjunction<C, A>>::value, "false/true type");
+
+  static_assert(!Conjunction<C, D>::value, "false/false value");
+  static_assert(std::is_base_of<C, Conjunction<C, D>>::value, "false/false type");
+};
+
+class TestDisjunction {
+  class A : public std::true_type {};
+  class B : public std::true_type {};
+  class C : public std::false_type {};
+  class D : public std::false_type {};
+
+  static_assert(!Disjunction<>::value, "nullary value");
+
+  static_assert(Disjunction<A>::value, "true value");
+  static_assert(std::is_base_of<A, Disjunction<A>>::value, "true type");
+
+  static_assert(!Disjunction<C>::value, "false value");
+  static_assert(std::is_base_of<C, Disjunction<C>>::value, "false type");
+
+  static_assert(Disjunction<A, B>::value, "true/true value");
+  static_assert(std::is_base_of<A, Disjunction<A, B>>::value, "true/true type");
+
+  static_assert(Disjunction<A, C>::value, "true/false value");
+  static_assert(std::is_base_of<A, Disjunction<A, C>>::value, "true/false type");
+
+  static_assert(Disjunction<C, A>::value, "false/true value");
+  static_assert(std::is_base_of<A, Disjunction<C, A>>::value, "false/true type");
+
+  static_assert(!Disjunction<C, D>::value, "false/false value");
+  static_assert(std::is_base_of<D, Disjunction<C, D>>::value, "false/false type");
+};
+
+class TestNegation {
+  static_assert(Negation<std::false_type>::value, "false -> true");
+  static_assert(!Negation<std::true_type>::value, "true -> false");
+};