1/*
2 * Copyright (c) 1998, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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.
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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
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23 */
24
25#ifndef SHARE_RUNTIME_BASICLOCK_HPP
26#define SHARE_RUNTIME_BASICLOCK_HPP
27
28#include "oops/markOop.hpp"
29#include "runtime/handles.hpp"
30
31class BasicLock {
32 friend class VMStructs;
33 friend class JVMCIVMStructs;
34 private:
35 volatile markOop _displaced_header;
36 public:
37 markOop displaced_header() const { return _displaced_header; }
38 void set_displaced_header(markOop header) { _displaced_header = header; }
39
40 void print_on(outputStream* st) const;
41
42 // move a basic lock (used during deoptimization
43 void move_to(oop obj, BasicLock* dest);
44
45 static int displaced_header_offset_in_bytes() { return offset_of(BasicLock, _displaced_header); }
46};
47
48// A BasicObjectLock associates a specific Java object with a BasicLock.
49// It is currently embedded in an interpreter frame.
50
51// Because some machines have alignment restrictions on the control stack,
52// the actual space allocated by the interpreter may include padding words
53// after the end of the BasicObjectLock. Also, in order to guarantee
54// alignment of the embedded BasicLock objects on such machines, we
55// put the embedded BasicLock at the beginning of the struct.
56
57class BasicObjectLock {
58 friend class VMStructs;
59 private:
60 BasicLock _lock; // the lock, must be double word aligned
61 oop _obj; // object holds the lock;
62
63 public:
64 // Manipulation
65 oop obj() const { return _obj; }
66 void set_obj(oop obj) { _obj = obj; }
67 BasicLock* lock() { return &_lock; }
68
69 // Note: Use frame::interpreter_frame_monitor_size() for the size of BasicObjectLocks
70 // in interpreter activation frames since it includes machine-specific padding.
71 static int size() { return sizeof(BasicObjectLock)/wordSize; }
72
73 // GC support
74 void oops_do(OopClosure* f) { f->do_oop(&_obj); }
75
76 static int obj_offset_in_bytes() { return offset_of(BasicObjectLock, _obj); }
77 static int lock_offset_in_bytes() { return offset_of(BasicObjectLock, _lock); }
78};
79
80
81#endif // SHARE_RUNTIME_BASICLOCK_HPP
82