[turbofan] Further adapting machine graph verifier to code stubs.

src/compiler/pipeline.cc

 // Copyright 2014 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/compiler/pipeline.h"
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <memory>
 #include <sstream>
 
@@ skipping 1635 matching lines @@
   if (FLAG_turbo_stats || FLAG_turbo_stats_nvp) {
     pipeline_statistics.reset(new PipelineStatistics(&info, &zone_stats));
     pipeline_statistics->BeginPhaseKind("stub codegen");
   }
 
   PipelineImpl pipeline(&data);
   DCHECK_NOT_NULL(data.schedule());
 
   if (FLAG_trace_turbo) {
     {
+      CodeTracer::Scope tracing_scope(isolate->GetCodeTracer());
+      OFStream os(tracing_scope.file());
+      os << "---------------------------------------------------\n"
+         << "Begin compiling " << debug_name << " using Turbofan" << std::endl;
+    }
+    {
       TurboJsonFile json_of(&info, std::ios_base::trunc);
       json_of << "{\"function\":\"" << info.GetDebugName().get()
               << "\", \"source\":\"\",\n\"phases\":[";
     }
     pipeline.Run<PrintGraphPhase>("Machine");
   }
 
   pipeline.Run<VerifyGraphPhase>(false, true);
   return pipeline.ScheduleAndGenerateCode(call_descriptor);
 }
@@ skipping 308 matching lines @@
   data->DeleteRegisterAllocationZone();
 }
 
 CompilationInfo* PipelineImpl::info() const { return data_->info(); }
 
 Isolate* PipelineImpl::isolate() const { return info()->isolate(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8