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| 1 // Copyright 2013 the V8 project authors. All rights reserved. |
| 2 // Redistribution and use in source and binary forms, with or without |
| 3 // modification, are permitted provided that the following conditions are |
| 4 // met: |
| 5 // |
| 6 // * Redistributions of source code must retain the above copyright |
| 7 // notice, this list of conditions and the following disclaimer. |
| 8 // * Redistributions in binary form must reproduce the above |
| 9 // copyright notice, this list of conditions and the following |
| 10 // disclaimer in the documentation and/or other materials provided |
| 11 // with the distribution. |
| 12 // * Neither the name of Google Inc. nor the names of its |
| 13 // contributors may be used to endorse or promote products derived |
| 14 // from this software without specific prior written permission. |
| 15 // |
| 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 |
| 28 #ifndef V8_SAMPLER_H_ |
| 29 #define V8_SAMPLER_H_ |
| 30 |
| 31 #include "atomicops.h" |
| 32 #include "v8globals.h" |
| 33 |
| 34 namespace v8 { |
| 35 namespace internal { |
| 36 |
| 37 class Isolate; |
| 38 |
| 39 // ---------------------------------------------------------------------------- |
| 40 // Sampler |
| 41 // |
| 42 // A sampler periodically samples the state of the VM and optionally |
| 43 // (if used for profiling) the program counter and stack pointer for |
| 44 // the thread that created it. |
| 45 |
| 46 // TickSample captures the information collected for each sample. |
| 47 struct TickSample { |
| 48 TickSample() |
| 49 : state(OTHER), |
| 50 pc(NULL), |
| 51 sp(NULL), |
| 52 fp(NULL), |
| 53 external_callback(NULL), |
| 54 frames_count(0) {} |
| 55 StateTag state; // The state of the VM. |
| 56 Address pc; // Instruction pointer. |
| 57 Address sp; // Stack pointer. |
| 58 Address fp; // Frame pointer. |
| 59 Address external_callback; |
| 60 static const int kMaxFramesCount = 64; |
| 61 Address stack[kMaxFramesCount]; // Call stack. |
| 62 int frames_count : 8; // Number of captured frames. |
| 63 }; |
| 64 |
| 65 class Sampler { |
| 66 public: |
| 67 // Initializes the Sampler support. Called once at VM startup. |
| 68 static void SetUp(); |
| 69 static void TearDown(); |
| 70 |
| 71 // Initialize sampler. |
| 72 Sampler(Isolate* isolate, int interval); |
| 73 virtual ~Sampler(); |
| 74 |
| 75 Isolate* isolate() const { return isolate_; } |
| 76 int interval() const { return interval_; } |
| 77 |
| 78 // Performs stack sampling. |
| 79 void SampleStack(TickSample* sample); |
| 80 |
| 81 // This method is called for each sampling period with the current |
| 82 // program counter. |
| 83 virtual void Tick(TickSample* sample) = 0; |
| 84 |
| 85 // Start and stop sampler. |
| 86 void Start(); |
| 87 void Stop(); |
| 88 |
| 89 // Is the sampler used for profiling? |
| 90 bool IsProfiling() const { return NoBarrier_Load(&profiling_) > 0; } |
| 91 void IncreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, 1); } |
| 92 void DecreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, -1); } |
| 93 |
| 94 // Whether the sampler is running (that is, consumes resources). |
| 95 bool IsActive() const { return NoBarrier_Load(&active_); } |
| 96 |
| 97 // Used in tests to make sure that stack sampling is performed. |
| 98 int samples_taken() const { return samples_taken_; } |
| 99 void ResetSamplesTaken() { samples_taken_ = 0; } |
| 100 |
| 101 class PlatformData; |
| 102 PlatformData* platform_data() const { return data_; } |
| 103 |
| 104 private: |
| 105 void SetActive(bool value) { NoBarrier_Store(&active_, value); } |
| 106 |
| 107 Isolate* isolate_; |
| 108 const int interval_; |
| 109 Atomic32 profiling_; |
| 110 Atomic32 active_; |
| 111 PlatformData* data_; // Platform specific data. |
| 112 int samples_taken_; // Counts stack samples taken. |
| 113 DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler); |
| 114 }; |
| 115 |
| 116 |
| 117 } } // namespace v8::internal |
| 118 |
| 119 #endif // V8_SAMPLER_H_ |
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