Wait in heap tests for active concurrent sweeper threads.

test/cctest/test-heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 32 matching lines @@
 
 static void InitializeVM() {
   if (env.IsEmpty()) env = v8::Context::New();
   v8::HandleScope scope;
   env->Enter();
 }
 
 
 // Go through all incremental marking steps in one swoop.
 static void SimulateIncrementalMarking() {
+  MarkCompactCollector* collector = HEAP->mark_compact_collector();
   IncrementalMarking* marking = HEAP->incremental_marking();
+  if (collector->IsConcurrentSweepingInProgress()) {
+    collector->WaitUntilSweepingCompleted();
+  }
   CHECK(marking->IsMarking() || marking->IsStopped());
   if (marking->IsStopped()) {
     marking->Start();
   }
   CHECK(marking->IsMarking());
   while (!marking->IsComplete()) {
     marking->Step(MB, IncrementalMarking::NO_GC_VIA_STACK_GUARD);
   }
   CHECK(marking->IsComplete());
 }
@@ skipping 2944 matching lines @@
   // explicitly enqueued.
   SimulateIncrementalMarking();
 
   // Now enable the debugger which in turn will disable code flushing.
   CHECK(isolate->debug()->Load());
 
   // This cycle will bust the heap and subsequent cycles will go ballistic.
   heap->CollectAllGarbage(Heap::kNoGCFlags);
   heap->CollectAllGarbage(Heap::kNoGCFlags);
 }