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 151