1 /*
 2  * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  *
23  */
24 
25 #ifndef SHARE_OOPS_INSTANCEOOP_HPP
26 #define SHARE_OOPS_INSTANCEOOP_HPP
27 
28 #include "oops/oop.hpp"
29 #include <type_traits>
30 
31 // An instanceOop is an instance of a Java Class
32 // Evaluating "new HashTable()" will create an instanceOop.
33 
34 class instanceOopDesc : public oopDesc {
35  public:
36   // aligned header size.
37   static int header_size() { return sizeof(instanceOopDesc)/HeapWordSize; }
38 
39   // If compressed, the offset of the fields of the instance may not be aligned.
40   static int base_offset_in_bytes() {
41     return (UseCompressedClassPointers) ?
42             klass_gap_offset_in_bytes() :
43             sizeof(instanceOopDesc);
44 
45   }
46 };
47 
48 // See similar requirement for oopDesc.
49 static_assert(std::is_trivially_default_constructible<instanceOopDesc>::value, "required");
50 
51 #endif // SHARE_OOPS_INSTANCEOOP_HPP