// Copyright 2019 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 BASE_PROFILER_SUSPENDABLE_THREAD_DELEGATE_H_ #define BASE_PROFILER_SUSPENDABLE_THREAD_DELEGATE_H_ #include #include "base/base_export.h" #include "base/profiler/register_context.h" #include "base/profiler/thread_delegate.h" namespace base { // Platform-specific thread and stack manipulation delegate, for use by the // platform-independent stack copying/walking implementation in // StackSamplerImpl for suspension-based stack copying. // // IMPORTANT NOTE: Most methods in this interface are invoked while the target // thread is suspended so must not do any allocation from the heap, including // indirectly via use of DCHECK/CHECK or other logging statements. Otherwise the // implementation can deadlock on heap locks acquired by the target thread // before it was suspended. These functions are commented with "NO HEAP // ALLOCATIONS". class BASE_EXPORT SuspendableThreadDelegate : public ThreadDelegate { public: // Implementations of this interface should suspend the thread for the // object's lifetime. NO HEAP ALLOCATIONS between the time the thread is // suspended and resumed. class BASE_EXPORT ScopedSuspendThread { public: ScopedSuspendThread() = default; virtual ~ScopedSuspendThread() = default; ScopedSuspendThread(const ScopedSuspendThread&) = delete; ScopedSuspendThread& operator=(const ScopedSuspendThread&) = delete; virtual bool WasSuccessful() const = 0; }; SuspendableThreadDelegate() = default; // Creates an object that holds the thread suspended for its lifetime. virtual std::unique_ptr CreateScopedSuspendThread() = 0; // Gets the register context for the thread. // NO HEAP ALLOCATIONS. virtual bool GetThreadContext(RegisterContext* thread_context) = 0; // Returns true if the thread's stack can be copied, where the bottom address // of the thread is at |stack_pointer|. // NO HEAP ALLOCATIONS. virtual bool CanCopyStack(uintptr_t stack_pointer) = 0; }; } // namespace base #endif // BASE_PROFILER_SUSPENDABLE_THREAD_DELEGATE_H_