1/*
2 * Copyright (c) 2014, 2019, 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_UTILITIES_NATIVECALLSTACK_HPP
26#define SHARE_UTILITIES_NATIVECALLSTACK_HPP
27
28#include "memory/allocation.hpp"
29#include "services/nmtCommon.hpp"
30#include "utilities/ostream.hpp"
31
32/*
33 * This class represents a native call path (does not include Java frame)
34 *
35 * This class is developed in the context of native memory tracking, it can
36 * be an useful tool for debugging purpose.
37 *
38 * For example, following code should print out native call path:
39 *
40 * ....
41 * NativeCallStack here;
42 * here.print_on(tty);
43 * ....
44 *
45 * However, there are a couple of restrictions on this class. If the restrictions are
46 * not strictly followed, it may break native memory tracking badly.
47 *
48 * 1. Number of stack frames to capture, is defined by native memory tracking.
49 * This number has impacts on how much memory to be used by native
50 * memory tracking.
51 * 2. The class is strict stack object, no heap or virtual memory can be allocated
52 * from it.
53 */
54class MemTracker;
55
56class NativeCallStack : public StackObj {
57private:
58 address _stack[NMT_TrackingStackDepth];
59 unsigned int _hash_value;
60
61public:
62 NativeCallStack(int toSkip = 0, bool fillStack = false);
63 NativeCallStack(address* pc, int frameCount);
64
65 static inline const NativeCallStack& empty_stack() {
66 static const NativeCallStack EMPTY_STACK(0, false);
67 return EMPTY_STACK;
68 }
69
70 // if it is an empty stack
71 inline bool is_empty() const {
72 return _stack[0] == NULL;
73 }
74
75 // number of stack frames captured
76 int frames() const;
77
78 inline int compare(const NativeCallStack& other) const {
79 return memcmp(_stack, other._stack, sizeof(_stack));
80 }
81
82 inline bool equals(const NativeCallStack& other) const {
83 // compare hash values
84 if (hash() != other.hash()) return false;
85 // compare each frame
86 return compare(other) == 0;
87 }
88
89 inline address get_frame(int index) const {
90 assert(index >= 0 && index < NMT_TrackingStackDepth, "Index out of bound");
91 return _stack[index];
92 }
93
94 // Hash code. Any better algorithm?
95 unsigned int hash() const;
96
97 void print_on(outputStream* out) const;
98 void print_on(outputStream* out, int indent) const;
99};
100
101#endif // SHARE_UTILITIES_NATIVECALLSTACK_HPP
102