Revert of Reland "Remove support for thread-based recompilation"

src/hydrogen.cc

 // Copyright 2013 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 "src/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 3455 matching lines @@
 
 HBasicBlock* HGraph::CreateBasicBlock() {
   HBasicBlock* result = new(zone()) HBasicBlock(this);
   blocks_.Add(result, zone());
   return result;
 }
 
 
 void HGraph::FinalizeUniqueness() {
   DisallowHeapAllocation no_gc;
+  DCHECK(!OptimizingCompilerThread::IsOptimizerThread(isolate()));
   for (int i = 0; i < blocks()->length(); ++i) {
     for (HInstructionIterator it(blocks()->at(i)); !it.Done(); it.Advance()) {
       it.Current()->FinalizeUniqueness();
     }
   }
 }
 
 
 int HGraph::SourcePositionToScriptPosition(SourcePosition pos) {
   return (FLAG_hydrogen_track_positions && !pos.IsUnknown())
@@ skipping 9466 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal