Use a bit in the handle structure to indicate if it is a prologue weak handle instead of the taggin…

runtime/vm/scavenger.cc

 // Copyright (c) 2011, 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/scavenger.h"
 
 #include <algorithm>
 #include <map>
 #include <utility>
 
@@ skipping 261 matching lines @@
 class ScavengerWeakVisitor : public HandleVisitor {
  public:
   // 'prologue_weak_were_strong' is currently only used for sanity checking.
   explicit ScavengerWeakVisitor(Scavenger* scavenger,
                                 bool prologue_weak_were_strong)
       :  HandleVisitor(Isolate::Current()),
          scavenger_(scavenger),
          prologue_weak_were_strong_(prologue_weak_were_strong) {
   }
 
-  void VisitHandle(uword addr, bool is_prologue_weak) {
+  void VisitHandle(uword addr) {
     FinalizablePersistentHandle* handle =
       reinterpret_cast<FinalizablePersistentHandle*>(addr);
     RawObject** p = handle->raw_addr();
     if (scavenger_->IsUnreachable(p)) {
-      ASSERT(!is_prologue_weak || !prologue_weak_were_strong_);
-      handle->UpdateUnreachable(isolate(), is_prologue_weak);
+      ASSERT(!handle->IsPrologueWeakPersistent() ||
+             !prologue_weak_were_strong_);
+      handle->UpdateUnreachable(isolate());
     } else {
       handle->UpdateRelocated(isolate());
     }
   }
 
  private:
   Scavenger* scavenger_;
   bool prologue_weak_were_strong_;
 
   DISALLOW_COPY_AND_ASSIGN(ScavengerWeakVisitor);
@@ skipping 480 matching lines @@
 
 
 void Scavenger::FreeExternal(intptr_t size) {
   ASSERT(size >= 0);
   external_size_ -= size;
   ASSERT(external_size_ >= 0);
   end_ = Utils::Minimum(to_->end(), end_ + size);
 }
 
 }  // namespace dart