1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_RUNTIME_BACKTRACE_HELPER_H_ 18 #define ART_RUNTIME_BACKTRACE_HELPER_H_ 19 20 #include <stddef.h> 21 #include <stdint.h> 22 23 namespace art { 24 25 // Using libbacktrace 26 class BacktraceCollector { 27 public: BacktraceCollector(uintptr_t * out_frames,size_t max_depth,size_t skip_count)28 BacktraceCollector(uintptr_t* out_frames, size_t max_depth, size_t skip_count) 29 : out_frames_(out_frames), max_depth_(max_depth), skip_count_(skip_count) {} 30 NumFrames()31 size_t NumFrames() const { 32 return num_frames_; 33 } 34 35 // Collect the backtrace, do not call more than once. 36 void Collect(); 37 38 private: 39 uintptr_t* const out_frames_ = nullptr; 40 size_t num_frames_ = 0u; 41 const size_t max_depth_ = 0u; 42 size_t skip_count_ = 0u; 43 }; 44 45 // A bounded sized backtrace. 46 template <size_t kMaxFrames> 47 class FixedSizeBacktrace { 48 public: Collect(size_t skip_count)49 void Collect(size_t skip_count) { 50 BacktraceCollector collector(frames_, kMaxFrames, skip_count); 51 collector.Collect(); 52 num_frames_ = collector.NumFrames(); 53 } 54 Hash()55 uint64_t Hash() const { 56 uint64_t hash = 9314237; 57 for (size_t i = 0; i < num_frames_; ++i) { 58 hash = hash * 2654435761 + frames_[i]; 59 hash += (hash >> 13) ^ (hash << 6); 60 } 61 return hash; 62 } 63 64 private: 65 uintptr_t frames_[kMaxFrames]; 66 size_t num_frames_; 67 }; 68 69 } // namespace art 70 71 #endif // ART_RUNTIME_BACKTRACE_HELPER_H_ 72