[turbofan] Enable concurrent (re)compilation.

src/compiler/pipeline.h

Index: src/compiler/pipeline.h
diff --git a/src/compiler/pipeline.h b/src/compiler/pipeline.h
index 240ff69f59c58d46c57e3d5180e1125981db9aa7..df4feb18cd3dd339abf1102a8f8d1ac79d5e723c 100644
--- a/src/compiler/pipeline.h
+++ b/src/compiler/pipeline.h
@@ -21,9 +21,15 @@ class PipelineData;
 class RegisterConfiguration;
 class Schedule;
 
-class Pipeline {
+class Pipeline final {
  public:
-  explicit Pipeline(CompilationInfo* info) : info_(info) {}
+  explicit Pipeline(CompilationInfo* info);
+  ~Pipeline();
+
+  // Separate pipeline steps.
+  bool CreateGraph();
+  bool OptimizeGraph();
+  Handle<Code> CreateCode() { return DoGenerateCode(); }
 
   // Run the entire pipeline and generate a handle to a code object.
   Handle<Code> GenerateCode();
@@ -50,12 +56,15 @@ class Pipeline {
   static inline bool SupportedTarget() { return V8_TURBOFAN_TARGET != 0; }
 
  private:
+  explicit Pipeline(PipelineData* data) : data_(data) {
+    DCHECK_NOT_NULL(data_);
+  }
+
   static Handle<Code> GenerateCodeForTesting(CompilationInfo* info,
                                              CallDescriptor* call_descriptor,
                                              Graph* graph, Schedule* schedule);
 
-  CompilationInfo* info_;
-  PipelineData* data_;
+  PipelineData* const data_;
 
   // Helpers for executing pipeline phases.
   template <typename Phase>
@@ -63,11 +72,14 @@ class Pipeline {
   template <typename Phase, typename Arg0>
   void Run(Arg0 arg_0);
 
-  CompilationInfo* info() const { return info_; }
-  Isolate* isolate() { return info_->isolate(); }
+  PipelineData* data() const { return data_; }
+  CompilationInfo* info() const;
+  Isolate* isolate() const { return info()->isolate(); }
 
   void BeginPhaseKind(const char* phase_kind);
   void RunPrintAndVerify(const char* phase, bool untyped = false);
+  bool ScheduleAndAllocateRegisters(CallDescriptor* call_descriptor);
+  Handle<Code> DoGenerateCode();
   Handle<Code> ScheduleAndGenerateCode(CallDescriptor* call_descriptor);
   void AllocateRegisters(const RegisterConfiguration* config,
                          bool run_verifier);