Revert "Revert "Finalize reachable weak persistent handles at isolate shutdown.""

runtime/vm/isolate.cc

 // Copyright (c) 2012, 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/isolate.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "lib/mirrors.h"
 #include "vm/compiler_stats.h"
@@ skipping 363 matching lines @@
   }
   invoked_functions.Sort(MostUsedFunctionFirst);
   for (int i = 0; i < invoked_functions.length(); i++) {
     OS::Print("%10"Pd" x %s\n",
         invoked_functions[i]->usage_counter(),
         invoked_functions[i]->ToFullyQualifiedCString());
   }
 }
 
 
+class FinalizeWeakPersistentHandlesVisitor : public HandleVisitor {
+ public:
+  FinalizeWeakPersistentHandlesVisitor() {
+  }
+
+  void VisitHandle(uword addr) {
+    FinalizablePersistentHandle* handle =
+        reinterpret_cast<FinalizablePersistentHandle*>(addr);
+    FinalizablePersistentHandle::Finalize(handle);
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FinalizeWeakPersistentHandlesVisitor);
+};
+
+
 void Isolate::Shutdown() {
   ASSERT(this == Isolate::Current());
   ASSERT(top_resource() == NULL);
   ASSERT((heap_ == NULL) || heap_->Verify());
 
   // Clean up debugger resources. Shutting down the debugger
   // requires a handle zone. We must set up a temporary zone because
   // Isolate::Shutdown is called without a zone.
   {
     Zone zone(this);
     HandleScope handle_scope(this);
     debugger_->Shutdown();
   }
 
   // Close all the ports owned by this isolate.
   PortMap::ClosePorts(message_handler());
 
   // Fail fast if anybody tries to post any more messsages to this isolate.
   delete message_handler();
   set_message_handler(NULL);
 
+  // Finalize any weak persistent handles with a non-null referent.
+  FinalizeWeakPersistentHandlesVisitor visitor;
+  api_state()->weak_persistent_handles().VisitHandles(&visitor);
+
   // Dump all accumalated timer data for the isolate.
   timer_list_.ReportTimers();
   if (FLAG_report_usage_count) {
     PrintInvokedFunctions();
   }
   CompilerStats::Print();
   if (FLAG_generate_gdb_symbols) {
     DebugInfo::UnregisterAllSections();
   }
   if (FLAG_trace_isolates) {
@@ skipping 56 matching lines @@
 
 
 void Isolate::VisitWeakPersistentHandles(HandleVisitor* visitor,
                                          bool visit_prologue_weak_handles) {
   if (api_state() != NULL) {
     api_state()->VisitWeakHandles(visitor, visit_prologue_weak_handles);
   }
 }
 
 }  // namespace dart