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| 1 /* | |
| 2 * Copyright (C) 2010, 2013 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 COMPUTER, 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 COMPUTER, 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 | |
| 27 #ifndef StackBounds_h | |
| 28 #define StackBounds_h | |
| 29 | |
| 30 namespace WTF { | |
| 31 | |
| 32 class StackBounds { | |
| 33 // isSafeToRecurse() / recursionLimit() tests (by default) | |
| 34 // that we are at least this far from the end of the stack. | |
| 35 // | |
| 36 // This 64k number was picked because a sampling of stack usage differences | |
| 37 // between consecutive entries into one of the Interpreter::execute...() | |
| 38 // functions was seen to be as high as 27k. Hence, 64k is chosen as a | |
| 39 // conservative availability value that is not too large but comfortably | |
| 40 // exceeds 27k with some buffer for error. | |
| 41 const static size_t s_defaultAvailabilityDelta = 64 * 1024; | |
| 42 | |
| 43 public: | |
| 44 static StackBounds currentThreadStackBounds() | |
| 45 { | |
| 46 StackBounds bounds; | |
| 47 bounds.initialize(); | |
| 48 bounds.checkConsistency(); | |
| 49 return bounds; | |
| 50 } | |
| 51 | |
| 52 bool isSafeToRecurse(size_t minAvailableDelta = s_defaultAvailabilityDelta)
const | |
| 53 { | |
| 54 checkConsistency(); | |
| 55 if (isGrowingDownward()) | |
| 56 return current() >= recursionLimit(minAvailableDelta); | |
| 57 return current() <= recursionLimit(minAvailableDelta); | |
| 58 } | |
| 59 | |
| 60 void* origin() const | |
| 61 { | |
| 62 ASSERT(m_origin); | |
| 63 return m_origin; | |
| 64 } | |
| 65 | |
| 66 size_t size() const | |
| 67 { | |
| 68 if (isGrowingDownward()) | |
| 69 return static_cast<char*>(m_origin) - static_cast<char*>(m_bound); | |
| 70 return static_cast<char*>(m_bound) - static_cast<char*>(m_origin); | |
| 71 } | |
| 72 | |
| 73 private: | |
| 74 StackBounds() | |
| 75 : m_origin(0) | |
| 76 , m_bound(0) | |
| 77 { | |
| 78 } | |
| 79 | |
| 80 void initialize(); | |
| 81 | |
| 82 void* current() const | |
| 83 { | |
| 84 checkConsistency(); | |
| 85 void* currentPosition = ¤tPosition; | |
| 86 return currentPosition; | |
| 87 } | |
| 88 | |
| 89 void* recursionLimit(size_t minAvailableDelta = s_defaultAvailabilityDelta)
const | |
| 90 { | |
| 91 checkConsistency(); | |
| 92 if (isGrowingDownward()) | |
| 93 return static_cast<char*>(m_bound) + minAvailableDelta; | |
| 94 return static_cast<char*>(m_bound) - minAvailableDelta; | |
| 95 } | |
| 96 | |
| 97 bool isGrowingDownward() const | |
| 98 { | |
| 99 ASSERT(m_origin && m_bound); | |
| 100 #if OS(WINCE) | |
| 101 return m_origin > m_bound; | |
| 102 #else | |
| 103 return true; | |
| 104 #endif | |
| 105 } | |
| 106 | |
| 107 void checkConsistency() const | |
| 108 { | |
| 109 #if !ASSERT_DISABLED | |
| 110 void* currentPosition = ¤tPosition; | |
| 111 ASSERT(m_origin != m_bound); | |
| 112 ASSERT(isGrowingDownward() | |
| 113 ? (currentPosition < m_origin && currentPosition > m_bound) | |
| 114 : (currentPosition > m_origin && currentPosition < m_bound)); | |
| 115 #endif | |
| 116 } | |
| 117 | |
| 118 void* m_origin; | |
| 119 void* m_bound; | |
| 120 | |
| 121 friend class StackStats; | |
| 122 }; | |
| 123 | |
| 124 } // namespace WTF | |
| 125 | |
| 126 using WTF::StackBounds; | |
| 127 | |
| 128 #endif | |
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Chromium Code Reviews
Issue 14238015:
Move Source/WTF/wtf to Source/wtf (Closed)
Base URL: svn://svn.chromium.org/blink/trunk