--- /dev/null	2019-10-01 11:37:31.106015611 +0200
+++ new/src/hotspot/os/windows/gc/z/zMapper_windows.hpp	2019-10-31 09:39:44.641040374 +0100
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2019, 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 OS_WINDOWS_GC_Z_ZMAPPER_WINDOWS_HPP
+#define OS_WINDOWS_GC_Z_ZMAPPER_WINDOWS_HPP
+
+#include "memory/allocation.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+#include <Windows.h>
+
+class ZMapper : public AllStatic {
+private:
+  // Create paging file mapping
+  static HANDLE create_paging_file_mapping(size_t size);
+
+  // Commit paging file mapping
+  static bool commit_paging_file_mapping(HANDLE file_handle, uintptr_t file_offset, size_t size);
+
+  // Map a view anywhere without a placeholder
+  static uintptr_t map_view_no_placeholder(HANDLE file_handle, uintptr_t file_offset, size_t size);
+
+  // Unmap a view without preserving a placeholder
+  static void unmap_view_no_placeholder(uintptr_t addr, size_t size);
+
+  // Commit memory covering the given virtual address range
+  static uintptr_t commit(uintptr_t addr, size_t size);
+
+public:
+  // Reserve memory with a placeholder
+  static uintptr_t reserve(uintptr_t addr, size_t size);
+
+  // Unreserve memory
+  static void unreserve(uintptr_t addr, size_t size);
+
+  // Create and commit paging file mapping
+  static HANDLE create_and_commit_paging_file_mapping(size_t size);
+
+  // Close paging file mapping
+  static void close_paging_file_mapping(HANDLE file_handle);
+
+  // Split a placeholder
+  //
+  // A view can only replace an entire placeholder, so placeholders need to be
+  // split and coalesced to be the exact size of the new views.
+  // [addr, addr + size) needs to be a proper sub-placeholder of an existing
+  // placeholder.
+  static void split_placeholder(uintptr_t addr, size_t size);
+
+  // Coalesce a placeholder
+  //
+  // [addr, addr + size) is the new placeholder. A sub-placeholder needs to
+  // exist within that range.
+  static void coalesce_placeholders(uintptr_t addr, size_t size);
+
+  // Map a view of the file handle and replace the placeholder covering the
+  // given virtual address range
+  static void map_view_replace_placeholder(HANDLE file_handle, uintptr_t file_offset, uintptr_t addr, size_t size);
+
+  // Unmap the view and reinstate a placeholder covering the given virtual
+  // address range
+  static void unmap_view_preserve_placeholder(uintptr_t addr, size_t size);
+};
+
+#endif // OS_WINDOWS_GC_Z_ZMAPPER_WINDOWS_HPP