| // Copyright 2017 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef CHROME_PROFILING_BACKTRACE_H_ |
| #define CHROME_PROFILING_BACKTRACE_H_ |
| |
| #include <functional> |
| #include <vector> |
| |
| #include "base/macros.h" |
| #include "chrome/profiling/address.h" |
| |
| namespace profiling { |
| |
| // Holds a move-only stack backtrace and a precomputed hash. This backtrace |
| // uses addresses in the instrumented process. This is in contrast to |
| // base::StackTrace which is for getting and working with stack traces in the |
| // current process. |
| // |
| // This is immutable since we assume it can be read from multiple threads |
| // without locking. |
| // |
| // This class has a ref_count member which is used by the allocation tracker |
| // to track references to the stack. The reference counting is managed |
| // externally. Tracking live objects with a global atom list in a threadsafe |
| // manner is much more difficult if this class derives from RefCount. |
| class Backtrace { |
| public: |
| // Move-only class. Backtraces should be managed by BacktraceStorage and |
| // we shouldn't be copying vectors around. |
| explicit Backtrace(std::vector<Address>&& a); |
| Backtrace(Backtrace&& other) noexcept; |
| ~Backtrace(); |
| |
| Backtrace& operator=(Backtrace&& other); |
| |
| bool operator==(const Backtrace& other) const; |
| bool operator!=(const Backtrace& other) const; |
| |
| const std::vector<Address>& addrs() const { return addrs_; } |
| |
| size_t fingerprint() const { return fingerprint_; } |
| |
| private: |
| friend class BacktraceStorage; // Only BacktraceStorage can do ref counting. |
| |
| // The reference counting is not threadsafe. it's assumed the |
| // BacktraceStorage is the only class accessing this, and it's done inside a |
| // lock. |
| void AddRef() const { ref_count_++; } |
| bool Release() const { // Returns whether the result is non-zero. |
| return !!(--ref_count_); |
| } |
| |
| std::vector<Address> addrs_; |
| size_t fingerprint_; |
| mutable int ref_count_ = 0; |
| |
| DISALLOW_COPY_AND_ASSIGN(Backtrace); |
| }; |
| |
| } // namespace profiling |
| |
| namespace std { |
| |
| template <> |
| struct hash<profiling::Backtrace> { |
| using argument_type = profiling::Backtrace; |
| using result_type = size_t; |
| result_type operator()(const argument_type& s) const { |
| return s.fingerprint(); |
| } |
| }; |
| |
| } // namespace std |
| |
| #endif // CHROME_PROFILING_BACKTRACE_H_ |