Revert "Removed default Isolate."

src/v8.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #include "assembler.h"
 #include "isolate.h"
 #include "elements.h"
 #include "bootstrapper.h"
@@ skipping 35 matching lines @@
   platform->SetThreadPoolSize(isolate->max_available_threads());
   // We currently only start the threads early, if we know that we'll use them.
   if (FLAG_job_based_sweeping) platform->EnsureInitialized();
 #endif
 
   return isolate->Init(des);
 }
 
 
 void V8::TearDown() {
+  Isolate* isolate = Isolate::Current();
+  ASSERT(isolate->IsDefaultIsolate());
+  if (!isolate->IsInitialized()) return;
+
+  // The isolate has to be torn down before clearing the LOperand
+  // caches so that the optimizing compiler thread (if running)
+  // doesn't see an inconsistent view of the lithium instructions.
+  isolate->TearDown();
+  delete isolate;
+
   Bootstrapper::TearDownExtensions();
   ElementsAccessor::TearDown();
   LOperand::TearDownCaches();
   ExternalReference::TearDownMathExpData();
   RegisteredExtension::UnregisterAll();
   Isolate::GlobalTearDown();
 
   Sampler::TearDown();
   Serializer::TearDown();
 
@@ skipping 65 matching lines @@
   platform_ = NULL;
 }
 
 
 v8::Platform* V8::GetCurrentPlatform() {
   ASSERT(platform_);
   return platform_;
 }
 
 } }  // namespace v8::internal