Use a tag bit for indicating prologue weak persistent handles, this avoids

runtime/vm/isolate.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 "vm/isolate.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/json.h"
 #include "lib/mirrors.h"
@@ skipping 710 matching lines @@
         invoked_functions[i]->ToFullyQualifiedCString());
   }
 }
 
 
 class FinalizeWeakPersistentHandlesVisitor : public HandleVisitor {
  public:
   FinalizeWeakPersistentHandlesVisitor() {
   }
 
-  void VisitHandle(uword addr) {
+  void VisitHandle(uword addr, bool is_prologue_weak) {
     FinalizablePersistentHandle* handle =
         reinterpret_cast<FinalizablePersistentHandle*>(addr);
-    FinalizablePersistentHandle::Finalize(handle);
+    FinalizablePersistentHandle::Finalize(handle, is_prologue_weak);
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FinalizeWeakPersistentHandlesVisitor);
 };
 
 
 void Isolate::Shutdown() {
   ASSERT(this == Isolate::Current());
   ASSERT(top_resource() == NULL);
@@ skipping 27 matching lines @@
     }
 
     // Write out profiler data if requested.
     Profiler::WriteProfile(this);
 
     // Write out the coverage data if collection has been enabled.
     CodeCoverage::Write(this);
 
     // Finalize any weak persistent handles with a non-null referent.
     FinalizeWeakPersistentHandlesVisitor visitor;
-    api_state()->weak_persistent_handles().VisitHandles(&visitor);
-    api_state()->prologue_weak_persistent_handles().VisitHandles(&visitor);
+    api_state()->weak_persistent_handles().VisitHandles(&visitor, false);
+    api_state()->prologue_weak_persistent_handles().VisitHandles(
+        &visitor, true);
 
     CompilerStats::Print();
     if (FLAG_trace_isolates) {
       heap()->PrintSizes();
       megamorphic_cache_table()->PrintSizes();
       Symbols::DumpStats();
       OS::Print("[-] Stopping isolate:\n"
                 "\tisolate:    %s\n", name());
     }
   }
@@ skipping 285 matching lines @@
   return func.raw();
 }
 
 
 void IsolateSpawnState::Cleanup() {
   SwitchIsolateScope switch_scope(isolate());
   Dart::ShutdownIsolate();
 }
 
 }  // namespace dart