Profiler Take 2

runtime/vm/thread_interrupter_macos.cc

+// 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.
+
+#include "platform/globals.h"
+#if defined(TARGET_OS_MACOS)
+
+#include "vm/signal_handler.h"
+#include "vm/thread_interrupter.h"
+
+namespace dart {
+
+DECLARE_FLAG(bool, thread_interrupter);
+DECLARE_FLAG(bool, trace_thread_interrupter);
+
+class ThreadInterrupterMacOS : public AllStatic {
+ public:
+  static void ThreadInterruptSignalHandler(int signal, siginfo_t* info,
+                                           void* context_) {
+    if (signal != SIGPROF) {
+      return;
+    }
+    ThreadInterrupter::ThreadState* state =
+        ThreadInterrupter::CurrentThreadState();
+    if ((state == NULL) || (state->callback == NULL)) {
+      // No interrupter state or callback.
+      return;
+    }
+    ASSERT(Thread::Compare(state->id, Thread::GetCurrentThreadId()));
+
+    // Extract thread state.
+    ucontext_t* context = reinterpret_cast<ucontext_t*>(context_);
+    mcontext_t mcontext = context->uc_mcontext;
+    InterruptedThreadState its;
+    its.tid = state->id;
+    its.pc = SignalHandler::GetProgramCounter(mcontext);
+    its.fp = SignalHandler::GetFramePointer(mcontext);
+    its.sp = SignalHandler::GetStackPointer(mcontext);
+    state->callback(its, state->data);
+  }
+};
+
+
+void ThreadInterrupter::InterruptThreads(int64_t current_time) {
+  for (intptr_t i = 0; i < threads_size_; i++) {
+    ThreadState* state = threads_[i];
+    ASSERT(state->id != Thread::kInvalidThreadId);
+    if (FLAG_trace_thread_interrupter) {
+      OS::Print("ThreadInterrupter interrupting %p\n", state->id);
+    }
+    pthread_kill(state->id, SIGPROF);
+  }
+}
+
+void ThreadInterrupter::ThreadMain(uword parameters) {
+  ASSERT(FLAG_thread_interrupter);
+  ASSERT(initialized_);
+  SignalHandler::Install(ThreadInterrupterMacOS::ThreadInterruptSignalHandler);
+  if (FLAG_trace_thread_interrupter) {
+    OS::Print("ThreadInterrupter MacOS ready.\n");
+  }
+  {
+    // Signal to main thread we are ready.
+    MonitorLocker startup_ml(start_stop_monitor_);
+    thread_running_ = true;
+    interrupter_thread_id_ = Thread::GetCurrentThreadId();
+    startup_ml.Notify();
+  }
+  MonitorLocker ml(monitor_);
+  while (!shutdown_) {
+    int64_t current_time = OS::GetCurrentTimeMicros();
+    InterruptThreads(current_time);
+    ml.WaitMicros(interrupt_period_);
+  }
+  if (FLAG_trace_thread_interrupter) {
+    OS::Print("ThreadInterrupter MacOS exiting.\n");
+  }
+  {
+    // Signal to main thread we are exiting.
+    MonitorLocker shutdown_ml(start_stop_monitor_);
+    thread_running_ = false;
+    shutdown_ml.Notify();
+  }
+}
+
+}  // namespace dart
+
+#endif  // defined(TARGET_OS_MACOS)
+