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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 "ThreadingPrimitives.h" |  | 
| 30 |  | 
| 31 |  | 
| 32 // Define this flag to enable Stack stats collection. This feature is useful |  | 
| 33 // for getting a sample of native stack usage sizes. |  | 
| 34 // |  | 
| 35 // Enabling this will cause stats to be collected and written to a log file at |  | 
| 36 // various  instrumented points in the code. It will result in noticeable |  | 
| 37 // performance loss. Hence, this should only be enable when you want to do |  | 
| 38 // some stats location in your local build. This code is provided here as a |  | 
| 39 // convenience for collecting that data. It is not meant to be enabled by |  | 
| 40 // default on release or debug builds. |  | 
| 41 |  | 
| 42 // #define ENABLE_STACK_STATS 1 |  | 
| 43 |  | 
| 44 |  | 
| 45 namespace WTF { |  | 
| 46 |  | 
| 47 #if !ENABLE(STACK_STATS) |  | 
| 48 |  | 
| 49 class StackStats { |  | 
| 50 public: |  | 
| 51     // The CheckPoint class is for marking check points corresponding |  | 
| 52     // each location in code where a stack recursion check is being done. |  | 
| 53 |  | 
| 54     class CheckPoint { |  | 
| 55     public: |  | 
| 56         CheckPoint() { } |  | 
| 57     }; |  | 
| 58 |  | 
| 59     class PerThreadStats { |  | 
| 60     public: |  | 
| 61         PerThreadStats() { } |  | 
| 62     }; |  | 
| 63 |  | 
| 64     class LayoutCheckPoint { |  | 
| 65     public: |  | 
| 66         LayoutCheckPoint() { } |  | 
| 67     }; |  | 
| 68 |  | 
| 69     static void initialize() { } |  | 
| 70     static void probe() { } |  | 
| 71 }; |  | 
| 72 |  | 
| 73 #else // ENABLE(STACK_STATS) |  | 
| 74 |  | 
| 75 class StackStats { |  | 
| 76 public: |  | 
| 77     // The CheckPoint class is for marking check points corresponding |  | 
| 78     // each location in code where a stack recursion check is being done. |  | 
| 79 |  | 
| 80     class CheckPoint { |  | 
| 81     public: |  | 
| 82         CheckPoint(); |  | 
| 83         ~CheckPoint(); |  | 
| 84     private: |  | 
| 85         CheckPoint* m_prev; |  | 
| 86     }; |  | 
| 87 |  | 
| 88     class PerThreadStats { |  | 
| 89     public: |  | 
| 90         PerThreadStats(); |  | 
| 91 |  | 
| 92     private: |  | 
| 93         int m_reentryDepth; |  | 
| 94         char* m_stackStart; |  | 
| 95         CheckPoint* m_currentCheckPoint; |  | 
| 96 |  | 
| 97         friend class CheckPoint; |  | 
| 98         friend class StackStats; |  | 
| 99     }; |  | 
| 100 |  | 
| 101     class LayoutCheckPoint { |  | 
| 102     public: |  | 
| 103         LayoutCheckPoint(); |  | 
| 104         ~LayoutCheckPoint(); |  | 
| 105 |  | 
| 106     private: |  | 
| 107         LayoutCheckPoint* m_prev; |  | 
| 108         int m_depth; |  | 
| 109     }; |  | 
| 110 |  | 
| 111     // Initializes locks and the log file. Should only be called once. |  | 
| 112     static void initialize(); |  | 
| 113 |  | 
| 114     // Used for probing the stack at places where we suspect to be high |  | 
| 115     // points of stack usage but are NOT check points where stack recursion |  | 
| 116     // is checked. |  | 
| 117     // |  | 
| 118     // The more places where we add this probe, the more accurate our |  | 
| 119     // stats data will be. However, adding too many probes will also |  | 
| 120     // result in unnecessary performance loss. So, only add these probes |  | 
| 121     // judiciously where appropriate. |  | 
| 122     static void probe(); |  | 
| 123 |  | 
| 124 private: |  | 
| 125     // CheckPoint management: |  | 
| 126     static Mutex* s_sharedLock; |  | 
| 127     static CheckPoint* s_topCheckPoint; |  | 
| 128     static LayoutCheckPoint* s_firstLayoutCheckPoint; |  | 
| 129     static LayoutCheckPoint* s_topLayoutCheckPoint; |  | 
| 130 |  | 
| 131     // High watermark stats: |  | 
| 132     static int s_maxCheckPointDiff; |  | 
| 133     static int s_maxStackHeight; |  | 
| 134     static int s_maxReentryDepth; |  | 
| 135 |  | 
| 136     static int s_maxLayoutCheckPointDiff; |  | 
| 137     static int s_maxTotalLayoutCheckPointDiff; |  | 
| 138     static int s_maxLayoutReentryDepth; |  | 
| 139 |  | 
| 140     friend class CheckPoint; |  | 
| 141     friend class LayoutCheckPoint; |  | 
| 142 }; |  | 
| 143 |  | 
| 144 #endif // ENABLE(STACK_STATS) |  | 
| 145 |  | 
| 146 } // namespace WTF |  | 
| 147 |  | 
| 148 using WTF::StackStats; |  | 
| 149 |  | 
| 150 #endif // StackStats_h |  | 
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