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 unwindstack { 24 class Unwinder; 25 } 26 27 namespace art { 28 29 // Using libbacktrace 30 class BacktraceCollector { 31 public: BacktraceCollector(uintptr_t * out_frames,size_t max_depth,size_t skip_count)32 BacktraceCollector(uintptr_t* out_frames, size_t max_depth, size_t skip_count) 33 : out_frames_(out_frames), max_depth_(max_depth), skip_count_(skip_count) {} 34 NumFrames()35 size_t NumFrames() const { 36 return num_frames_; 37 } 38 39 // Collect the backtrace, do not call more than once. 40 void Collect(); 41 42 private: 43 // Try to collect backtrace. Returns false on failure. 44 // It is used to retry backtrace on temporary failure. 45 bool CollectImpl(unwindstack::Unwinder* unwinder); 46 47 uintptr_t* const out_frames_ = nullptr; 48 size_t num_frames_ = 0u; 49 const size_t max_depth_ = 0u; 50 size_t skip_count_ = 0u; 51 }; 52 53 // A bounded sized backtrace. 54 template <size_t kMaxFrames> 55 class FixedSizeBacktrace { 56 public: Collect(size_t skip_count)57 void Collect(size_t skip_count) { 58 BacktraceCollector collector(frames_, kMaxFrames, skip_count); 59 collector.Collect(); 60 num_frames_ = collector.NumFrames(); 61 } 62 Hash()63 uint64_t Hash() const { 64 uint64_t hash = 9314237; 65 for (size_t i = 0; i < num_frames_; ++i) { 66 hash = hash * 2654435761 + frames_[i]; 67 hash += (hash >> 13) ^ (hash << 6); 68 } 69 return hash; 70 } 71 72 private: 73 uintptr_t frames_[kMaxFrames]; 74 size_t num_frames_; 75 }; 76 77 } // namespace art 78 79 #endif // ART_RUNTIME_BACKTRACE_HELPER_H_ 80