[libcxx] Add <experimental/any> v2.

Summary:
This patch adds the second revision of <experimental/any>. 
I've been working from the LFTS draft found at this link. https://rawgit.com/cplusplus/fundamentals-ts/v1/fundamentals-ts.html#any



Reviewers: danalbert, jroelofs, K-ballo, mclow.lists

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D6762

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@243728 91177308-0d34-0410-b5e6-96231b3b80d8

test/libcxx/experimental/any/size_and_alignment.pass.cpp

@@ -0,0 +1,23 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+
+// <experimental/any>
+
+// Check that the size and alignment of any are what we expect.
+
+#include <experimental/any>
+
+int main()
+{
+    using std::experimental::any;
+    static_assert(sizeof(any) == sizeof(void*)*4, "");
+    static_assert(alignof(any) == alignof(void*), "");
+}

test/libcxx/experimental/any/small_type.pass.cpp

@@ -0,0 +1,40 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+
+// <experimental/any>
+
+// Check that the size and alignment of any are what we expect.
+
+#include <experimental/any>
+#include "any_helpers.h"
+
+class SmallThrowsDtor
+{
+public:
+    SmallThrowsDtor() {}
+    SmallThrowsDtor(SmallThrowsDtor const &) noexcept {}
+    SmallThrowsDtor(SmallThrowsDtor &&) noexcept {}
+    ~SmallThrowsDtor() noexcept(false) {}
+};
+
+int main()
+{
+    using std::experimental::any;
+    using std::experimental::__any_imp::_IsSmallObject;
+    static_assert(_IsSmallObject<small>::value, "");
+    static_assert(_IsSmallObject<void*>::value, "");
+    static_assert(!_IsSmallObject<SmallThrowsDtor>::value, "");
+    static_assert(!_IsSmallObject<large>::value, "");
+    // long double is over aligned.
+    static_assert(sizeof(long double) <= sizeof(void*) * 3, "");
+    static_assert(alignof(long double) > alignof(void*), "");
+    static_assert(!_IsSmallObject<long double>::value, "");
+}

test/libcxx/experimental/any/version.pass.cpp

@@ -0,0 +1,20 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <experimental/any>
+
+#include <experimental/any>
+
+#ifndef _LIBCPP_VERSION
+#error _LIBCPP_VERSION not defined
+#endif
+
+int main()
+{
+}