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runtime/vm/thread_registry.h

 // 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.
 
 #ifndef VM_THREAD_REGISTRY_H_
 #define VM_THREAD_REGISTRY_H_
 
 #include "vm/globals.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
 #include "vm/stack_frame.h"
 #include "vm/thread.h"
 
 namespace dart {
 
 // Unordered collection of threads relating to a particular isolate.
 class ThreadRegistry {
  public:
   ThreadRegistry()
       : monitor_(new Monitor()),
         entries_(),
         in_rendezvous_(false),
         remaining_(0),
         round_(0) {}
 
+  ~ThreadRegistry();
+
   // Bring all threads in this isolate to a safepoint. The caller is
   // expected to be implicitly at a safepoint. The threads will wait
   // until ResumeAllThreads is called. First participates in any
   // already pending rendezvous requested by another thread. Any
   // thread that tries to enter this isolate during rendezvous will
   // wait in RestoreStateTo. Nesting is not supported: the caller must
   // call ResumeAllThreads before making further calls to
   // SafepointThreads.
   void SafepointThreads();
 
@@ skipping 94 matching lines @@
       StackFrame* frame = frames_iterator.NextFrame();
       while (frame != NULL) {
         frame->VisitObjectPointers(visitor);
         frame = frames_iterator.NextFrame();
       }
     }
   }
 
  private:
   struct Entry {
+    // NOTE: |thread| is deleted automatically when the thread exits.
+    // In other words, it is not safe to dereference |thread| unless you are on
+    // the thread itself.
     Thread* thread;
     bool scheduled;
     Thread::State state;
   };
 
   // Returns Entry corresponding to thread in registry or NULL.
   // Note: Lock should be taken before this function is called.
   // TODO(koda): Add method Monitor::IsOwnedByCurrentThread.
   Entry* FindEntry(Thread* thread) {
     for (int i = 0; i < entries_.length(); ++i) {
@@ skipping 19 matching lines @@
   intptr_t remaining_;    // Number of threads yet to reach their safepoint.
   int64_t round_;         // Counter, to prevent missing updates to remaining_
                           // (see comments in CheckSafepointLocked).
 
   DISALLOW_COPY_AND_ASSIGN(ThreadRegistry);
 };
 
 }  // namespace dart
 
 #endif  // VM_THREAD_REGISTRY_H_