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1 /* | |
2 * Copyright (C) 2012 Apple Inc. All rights reserved. | |
3 * | |
4 * Redistribution and use in source and binary forms, with or without | |
5 * modification, are permitted provided that the following conditions | |
6 * are met: | |
7 * 1. Redistributions of source code must retain the above copyright | |
8 * notice, this list of conditions and the following disclaimer. | |
9 * 2. Redistributions in binary form must reproduce the above copyright | |
10 * notice, this list of conditions and the following disclaimer in the | |
11 * documentation and/or other materials provided with the distribution. | |
12 * | |
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY | |
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR | |
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY | |
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
24 */ | |
25 | |
26 #ifndef StackStats_h | |
27 #define StackStats_h | |
28 | |
29 #include "ExportMacros.h" | |
30 #include "ThreadingPrimitives.h" | |
31 | |
32 | |
33 // Define this flag to enable Stack stats collection. This feature is useful | |
34 // for getting a sample of native stack usage sizes. | |
35 // | |
36 // Enabling this will cause stats to be collected and written to a log file at | |
37 // various instrumented points in the code. It will result in noticeable | |
38 // performance loss. Hence, this should only be enable when you want to do | |
39 // some stats location in your local build. This code is provided here as a | |
40 // convenience for collecting that data. It is not meant to be enabled by | |
41 // default on release or debug builds. | |
42 | |
43 // #define ENABLE_STACK_STATS 1 | |
44 | |
45 | |
46 namespace WTF { | |
47 | |
48 #if !ENABLE(STACK_STATS) | |
49 | |
50 class StackStats { | |
51 public: | |
52 // The CheckPoint class is for marking check points corresponding | |
53 // each location in code where a stack recursion check is being done. | |
54 | |
55 class CheckPoint { | |
56 public: | |
57 CheckPoint() { } | |
58 }; | |
59 | |
60 class PerThreadStats { | |
61 public: | |
62 PerThreadStats() { } | |
63 }; | |
64 | |
65 class LayoutCheckPoint { | |
66 public: | |
67 LayoutCheckPoint() { } | |
68 }; | |
69 | |
70 static void initialize() { } | |
71 static void probe() { } | |
72 }; | |
73 | |
74 #else // ENABLE(STACK_STATS) | |
75 | |
76 class StackStats { | |
77 public: | |
78 // The CheckPoint class is for marking check points corresponding | |
79 // each location in code where a stack recursion check is being done. | |
80 | |
81 class CheckPoint { | |
82 public: | |
83 CheckPoint(); | |
84 ~CheckPoint(); | |
85 private: | |
86 CheckPoint* m_prev; | |
87 }; | |
88 | |
89 class PerThreadStats { | |
90 public: | |
91 PerThreadStats(); | |
92 | |
93 private: | |
94 int m_reentryDepth; | |
95 char* m_stackStart; | |
96 CheckPoint* m_currentCheckPoint; | |
97 | |
98 friend class CheckPoint; | |
99 friend class StackStats; | |
100 }; | |
101 | |
102 class LayoutCheckPoint { | |
103 public: | |
104 WTF_EXPORT_PRIVATE LayoutCheckPoint(); | |
105 WTF_EXPORT_PRIVATE ~LayoutCheckPoint(); | |
106 | |
107 private: | |
108 LayoutCheckPoint* m_prev; | |
109 int m_depth; | |
110 }; | |
111 | |
112 // Initializes locks and the log file. Should only be called once. | |
113 static void initialize(); | |
114 | |
115 // Used for probing the stack at places where we suspect to be high | |
116 // points of stack usage but are NOT check points where stack recursion | |
117 // is checked. | |
118 // | |
119 // The more places where we add this probe, the more accurate our | |
120 // stats data will be. However, adding too many probes will also | |
121 // result in unnecessary performance loss. So, only add these probes | |
122 // judiciously where appropriate. | |
123 static void probe(); | |
124 | |
125 private: | |
126 // CheckPoint management: | |
127 static Mutex* s_sharedLock; | |
128 static CheckPoint* s_topCheckPoint; | |
129 static LayoutCheckPoint* s_firstLayoutCheckPoint; | |
130 static LayoutCheckPoint* s_topLayoutCheckPoint; | |
131 | |
132 // High watermark stats: | |
133 static int s_maxCheckPointDiff; | |
134 static int s_maxStackHeight; | |
135 static int s_maxReentryDepth; | |
136 | |
137 static int s_maxLayoutCheckPointDiff; | |
138 static int s_maxTotalLayoutCheckPointDiff; | |
139 static int s_maxLayoutReentryDepth; | |
140 | |
141 friend class CheckPoint; | |
142 friend class LayoutCheckPoint; | |
143 }; | |
144 | |
145 #endif // ENABLE(STACK_STATS) | |
146 | |
147 } // namespace WTF | |
148 | |
149 using WTF::StackStats; | |
150 | |
151 #endif // StackStats_h | |
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