Clear reusable handles of helper threads as well. Visit mutator_thread_ even if it is not active (a…

runtime/vm/thread.cc

 // Copyright (c) 2015, 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 "vm/thread.h"
 
 #include "vm/dart_api_state.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
@@ skipping 244 matching lines @@
   }
   return false;
 }
 
 
 void Thread::ExitIsolateAsHelper(bool bypass_safepoint) {
   Thread* thread = Thread::Current();
   ASSERT(thread != NULL);
   ASSERT(!thread->IsMutatorThread());
   ASSERT(thread->execution_state() == Thread::kThreadInVM);
+  // Clear since GC will not visit the thread once it is unscheduled.
+  thread->ClearReusableHandles();
   thread->StoreBufferRelease();
   Isolate* isolate = thread->isolate();
   ASSERT(isolate != NULL);
   const bool kIsNotMutatorThread = false;
   isolate->UnscheduleThread(thread, kIsNotMutatorThread, bypass_safepoint);
 }
 
 
 void Thread::PrepareForGC() {
   ASSERT(IsAtSafepoint());
@@ skipping 229 matching lines @@
 
 DisableThreadInterruptsScope::~DisableThreadInterruptsScope() {
   if (thread() != NULL) {
     OSThread* os_thread = thread()->os_thread();
     ASSERT(os_thread != NULL);
     os_thread->EnableThreadInterrupts();
   }
 }
 
 }  // namespace dart