instanceOop.hpp revision 1472:c18cbe5936b8 
1/*
2 * Copyright (c) 1997, 2008, 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
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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.
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23 */
24
25// An instanceOop is an instance of a Java Class
26// Evaluating "new HashTable()" will create an instanceOop.
27
28class instanceOopDesc : public oopDesc {
29 public:
30  // aligned header size.
31  static int header_size() { return sizeof(instanceOopDesc)/HeapWordSize; }
32
33  // If compressed, the offset of the fields of the instance may not be aligned.
34  static int base_offset_in_bytes() {
35    return UseCompressedOops ?
36             klass_gap_offset_in_bytes() :
37             sizeof(instanceOopDesc);
38  }
39
40  static bool contains_field_offset(int offset, int nonstatic_field_size) {
41    int base_in_bytes = base_offset_in_bytes();
42    return (offset >= base_in_bytes &&
43            (offset-base_in_bytes) < nonstatic_field_size * heapOopSize);
44  }
45};
46