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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_RUNTIME_BACKTRACE_HELPER_H_
#define ART_RUNTIME_BACKTRACE_HELPER_H_
#include <stddef.h>
#include <stdint.h>
namespace unwindstack {
class Unwinder;
}
namespace art {
// Using libunwindstack
class BacktraceCollector {
public:
BacktraceCollector(uintptr_t* out_frames, size_t max_depth, size_t skip_count)
: out_frames_(out_frames), max_depth_(max_depth), skip_count_(skip_count) {}
size_t NumFrames() const {
return num_frames_;
}
// Collect the backtrace, do not call more than once.
void Collect();
private:
// Try to collect backtrace. Returns false on failure.
// It is used to retry backtrace on temporary failure.
bool CollectImpl(unwindstack::Unwinder* unwinder);
uintptr_t* const out_frames_ = nullptr;
size_t num_frames_ = 0u;
const size_t max_depth_ = 0u;
size_t skip_count_ = 0u;
};
// A bounded sized backtrace.
template <size_t kMaxFrames>
class FixedSizeBacktrace {
public:
void Collect(size_t skip_count) {
BacktraceCollector collector(frames_, kMaxFrames, skip_count);
collector.Collect();
num_frames_ = collector.NumFrames();
}
uint64_t Hash() const {
uint64_t hash = 9314237;
for (size_t i = 0; i < num_frames_; ++i) {
hash = hash * 2654435761 + frames_[i];
hash += (hash >> 13) ^ (hash << 6);
}
return hash;
}
private:
uintptr_t frames_[kMaxFrames];
size_t num_frames_;
};
} // namespace art
#endif // ART_RUNTIME_BACKTRACE_HELPER_H_