Make helper functions static to avoid accidental collision and potentially aid optimization.

runtime/vm/gc_marker.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/gc_marker.h"
 
 #include <map>
 #include <utility>
 #include <vector>
 
@@ skipping 264 matching lines @@
   typedef std::multimap<RawObject*, RawWeakProperty*> DelaySet;
   typedef std::pair<RawObject*, RawWeakProperty*> DelaySetEntry;
   DelaySet delay_set_;
   const bool visit_function_code_;
   GrowableArray<RawFunction*> skipped_code_functions_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(MarkingVisitor);
 };
 
 
-bool IsUnreachable(const RawObject* raw_obj) {
+static bool IsUnreachable(const RawObject* raw_obj) {
   if (!raw_obj->IsHeapObject()) {
     return false;
   }
   if (raw_obj == Object::null()) {
     return true;
   }
   if (!raw_obj->IsOldObject()) {
     return false;
   }
   return !raw_obj->IsMarked();
@@ skipping 215 matching lines @@
   MarkingWeakVisitor mark_weak;
   IterateWeakRoots(isolate, &mark_weak, invoke_api_callbacks);
   mark.Finalize();
   ProcessWeakTables(page_space);
   ProcessObjectIdTable(isolate);
 
   Epilogue(isolate, invoke_api_callbacks);
 }
 
 }  // namespace dart