Bugfix in process handle: Do detaching from owner process separately from derefing.

src/vm/process.cc

 // Copyright (c) 2014, the Fletch 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.md file.
 
 #include "src/vm/process.h"
 
 #include <errno.h>
 #include <stdlib.h>
 
 #include "src/shared/assert.h"
@@ skipping 91 matching lines @@
 #ifdef DEBUG
   true_then_false_ = true;
 #endif
 }
 
 Process::~Process() {
   // [Cleanup] should've been called at this point. So we ASSERT the post
   // conditions here.
   ASSERT(ports_ == NULL);
 
+  ProcessHandle::DecrementRef(process_handle_);
+
 #ifdef FLETCH_ENABLE_MULTIPLE_PROCESS_HEAPS
   heap_.ProcessWeakPointers();
 #endif  // #ifdef FLETCH_ENABLE_MULTIPLE_PROCESS_HEAPS
 
   delete debug_info_;
 
   ASSERT(next_ == NULL);
   ASSERT(cooked_stack_deltas_.is_empty());
 }
 
 void Process::Cleanup(Signal::Kind kind) {
   // Clear out the process pointer from all the ports.
   ASSERT(immutable_heap_ == NULL);
   while (ports_ != NULL) {
     Port* next = ports_->next();
     ports_->OwnerProcessTerminating();
     ports_ = next;
   }
 
   // We are going down at this point. If anything else is starting to
   // link/monitor with this [ProcessHandle], it will fail after this line.
-  ProcessHandle::OwnerProcessTerminating(process_handle_);
+  process_handle_->OwnerProcessTerminating();
 
   // Since nobody can send us messages (or signals) at this point, we can
   // propagate the exit signal.
   links()->CleanupWithSignal(process_handle(), kind);
 }
 
 void Process::SetupExecutionStack() {
   ASSERT(coroutine_ == NULL);
   Stack* stack = Stack::cast(NewStack(256));
   stack->set(0, NULL);
@@ skipping 712 matching lines @@
   while (queue != NULL) {
     Instance* channel = queue->port()->channel();
     if (channel != NULL) return channel;
     mailbox->AdvanceCurrentMessage();
     queue = mailbox->CurrentMessage();
   }
   return process->program()->null_object();
 }
 
 }  // namespace fletch