Profiler Take 2

runtime/vm/thread_interrupter.h

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef VM_THREAD_INTERRUPTER_H_
+#define VM_THREAD_INTERRUPTER_H_
+
+#include "vm/allocation.h"
+#include "vm/signal_handler.h"
+#include "vm/thread.h"
+
+
+namespace dart {
+
+struct InterruptedThreadState {
+  ThreadId tid;
+  uintptr_t pc;
+  uintptr_t sp;
+  uintptr_t fp;
+};
+
+// When a thread is interrupted the thread specific interrupt
+// callback will be invoked at the interrupt period. Each callback is given an
+// InterruptedThreadState and the thread specific data pointer. When inside a
+// thread interrupt callback doing any of the following
+// is forbidden:
+//   * Accessing TLS.
+//   * Allocating memory.
+//   * Taking a lock.
+typedef void (*ThreadInterruptCallback)(const InterruptedThreadState& state,
+                                        void* data);
+
+class ThreadInterrupter : public AllStatic {
+ public:
+  static void InitOnce();
+  static void Shutdown();
+
+  // Delay between interrupts.
+  static void SetInterruptPeriod(intptr_t period);
+
+  // Register the currently running thread for interrupts. If the current thread
+  // is already registered, callback and data will be updated.
+  static void Register(ThreadInterruptCallback callback, void* data);
+  // Unregister the currently running thread for interrupts.
+  static void Unregister();
+
+  // Enable interrupts for this thread. Does not alter callback.
+  static void Enable();
+  // Disable interrupts for this thread. Does not alter callback.
+  static void Disable();
+
+  // These functions do not guarantee that no signals will be delivered when
+  // blocked.
+  static void BlockSignals();
+  static void UnblockSignals();
+
+ private:
+  static const intptr_t kMaxThreads = 4096;
+  static bool initialized_;
+  static bool shutdown_;
+  static bool thread_running_;
+  static ThreadId interrupter_thread_id_;
+  static Monitor* monitor_;
+  static Monitor* start_stop_monitor_;
+  static intptr_t interrupt_period_;
+  static ThreadLocalKey thread_state_key_;
+  // State stored per registered thread.
+  struct ThreadState {
+    ThreadId id;
+    ThreadInterruptCallback callback;
+    void* data;
+  };
+
+  static void UpdateStateObject(ThreadInterruptCallback callback, void* data);
+  static ThreadState* CurrentThreadState();
+  static void SetCurrentThreadState(ThreadState* state);
+
+  // Registered thread table.
+  static ThreadState** threads_;
+  static intptr_t threads_capacity_;
+  static intptr_t threads_size_;
+  static void _EnsureThreadStateCreated();
+  static void _Enable();
+  static void _Disable();
+  static void ResizeThreads(intptr_t new_capacity);
+  static void AddThread(ThreadId id);
+  static intptr_t FindThreadIndex(ThreadId id);
+  static ThreadState* RemoveThread(intptr_t i);
+
+  friend class ThreadInterrupterAndroid;
+  friend class ThreadInterrupterMacOS;
+  friend class ThreadInterrupterLinux;
+  friend class ThreadInterrupterWin;
+
+  static void InterruptThreads(int64_t current_time);
+  static void ThreadMain(uword parameters);
+
+  static void InstallSignalHandler();
+};
+
+void ThreadInterruptNoOp(const InterruptedThreadState& state, void* data);
+
+}  // namespace dart
+
+#endif  // VM_THREAD_INTERRUPTER_H_