projects / apple / javascriptcore.git / blame
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| 6fe7ccc8 A |
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 ExecutionCounter_h | |
| 27 | #define ExecutionCounter_h | |
| 28 | ||
| 29 | #include <wtf/SimpleStats.h> | |
| 30 | ||
| 31 | namespace JSC { | |
| 32 | ||
| 33 | class CodeBlock; | |
| 34 | ||
| 35 | class ExecutionCounter { | |
| 36 | public: | |
| 37 | ExecutionCounter(); | |
| 38 | bool checkIfThresholdCrossedAndSet(CodeBlock*); | |
| 39 | void setNewThreshold(int32_t threshold, CodeBlock*); | |
| 40 | void deferIndefinitely(); | |
| 41 | static double applyMemoryUsageHeuristics(int32_t value, CodeBlock*); | |
| 42 | static int32_t applyMemoryUsageHeuristicsAndConvertToInt(int32_t value, CodeBlock*); | |
| 43 | ||
| 44 | static int32_t formattedTotalCount(float value) | |
| 45 | { | |
| 46 | union { | |
| 47 | int32_t i; | |
| 48 | float f; | |
| 49 | } u; | |
| 50 | u.f = value; | |
| 51 | return u.i; | |
| 52 | } | |
| 53 | ||
| 54 | private: | |
| 55 | bool hasCrossedThreshold(CodeBlock*) const; | |
| 56 | bool setThreshold(CodeBlock*); | |
| 57 | void reset(); | |
| 58 | ||
| 59 | public: | |
| 60 | ||
| 61 | // NB. These are intentionally public because it will be modified from machine code. | |
| 62 | ||
| 63 | // This counter is incremented by the JIT or LLInt. It starts out negative and is | |
| 64 | // counted up until it becomes non-negative. At the start of a counting period, | |
| 65 | // the threshold we wish to reach is m_totalCount + m_counter, in the sense that | |
| 66 | // we will add X to m_totalCount and subtract X from m_counter. | |
| 67 | int32_t m_counter; | |
| 68 | ||
| 69 | // Counts the total number of executions we have seen plus the ones we've set a | |
| 70 | // threshold for in m_counter. Because m_counter's threshold is negative, the | |
| 71 | // total number of actual executions can always be computed as m_totalCount + | |
| 72 | // m_counter. | |
| 73 | float m_totalCount; | |
| 74 | ||
| 75 | // This is the threshold we were originally targetting, without any correction for | |
| 76 | // the memory usage heuristics. | |
| 77 | int32_t m_activeThreshold; | |
| 78 | }; | |
| 79 | ||
| 80 | } // namespace JSC | |
| 81 | ||
| 82 | #endif // ExecutionCounter_h | |
| 83 |