Ensure profiler manager thread has shutdown before main thread

runtime/vm/profiler_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/isolate.h"
 #include "vm/json_stream.h"
 #include "vm/profiler.h"
 #include "vm/signal_handler.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, profile);
+DECLARE_FLAG(bool, trace_profiled_isolates);
 
 static void CollectSample(IsolateProfilerData* profiler_data,
                           uintptr_t pc,
                           uintptr_t fp,
                           uintptr_t sp,
                           uintptr_t stack_lower,
                           uintptr_t stack_upper) {
   SampleBuffer* sample_buffer = profiler_data->sample_buffer();
   Sample* sample = sample_buffer->ReserveSample();
   ASSERT(sample != NULL);
@@ skipping 96 matching lines @@
   ASSERT(lowest != max_time);
   ASSERT(lowest > 0);
   return lowest;
 }
 
 
 void ProfilerManager::ThreadMain(uword parameters) {
   ASSERT(initialized_);
   ASSERT(FLAG_profile);
   SignalHandler::Install(ProfileSignalAction);
+  if (FLAG_trace_profiled_isolates) {
+    OS::Print("ProfilerManager MacOS ready.\n");
+  }
+  thread_running_ = true;
+  {
+    // Signal to main thread we are ready.
+    ScopedMonitor startup_lock(start_stop_monitor_);
+    startup_lock.Notify();
+  }
   ScopedMonitor lock(monitor_);
   while (!shutdown_) {
     int64_t current_time = OS::GetCurrentTimeMicros();
     int64_t next_sample = SampleAndRescheduleIsolates(current_time);
     lock.WaitMicros(next_sample);
   }
+  if (FLAG_trace_profiled_isolates) {
+    OS::Print("ProfilerManager MacOS exiting.\n");
+  }
+  thread_running_ = false;
+  {
+    // Signal to main thread we are exiting.
+    ScopedMonitor shutdown_lock(start_stop_monitor_);
+    shutdown_lock.Notify();
+  }
 }
 
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)