[turbofan] Enable concurrent (re)compilation.

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index c90bf91e596c8376062f6c770e03e4273752a47e..a93587161105c01468ad8541fe3a19576c2cb9e9 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -14,11 +14,20 @@
 namespace v8 {
 namespace internal {
 
+// Forward declarations.
 class AstValueFactory;
 class HydrogenCodeStub;
 class ParseInfo;
 class ScriptData;
 
+namespace compiler {
+
+// Forward declarations.
+class Pipeline;
+
+}  // namespace compiler
+
+
 struct OffsetRange {
   OffsetRange(int from, int to) : from(from), to(to) {}
   int from;
@@ -514,11 +523,13 @@ class OptimizedCompileJob: public ZoneObject {
  public:
   explicit OptimizedCompileJob(CompilationInfo* info)
       : info_(info),
+        pipeline_(nullptr),
         graph_builder_(NULL),
         graph_(NULL),
         chunk_(NULL),
         last_status_(FAILED),
-        awaiting_install_(false) { }
+        awaiting_install_(false) {}
+  ~OptimizedCompileJob();
 
   enum Status {
     FAILED, BAILED_OUT, SUCCEEDED
@@ -530,6 +541,7 @@ class OptimizedCompileJob: public ZoneObject {
 
   Status last_status() const { return last_status_; }
   CompilationInfo* info() const { return info_; }
+  compiler::Pipeline* pipeline() const { return pipeline_; }
   Isolate* isolate() const { return info()->isolate(); }
 
   Status RetryOptimization(BailoutReason reason) {
@@ -550,7 +562,8 @@ class OptimizedCompileJob: public ZoneObject {
   bool IsWaitingForInstall() { return awaiting_install_; }
 
  private:
-  CompilationInfo* info_;
+  CompilationInfo* const info_;
+  compiler::Pipeline* pipeline_;
   HOptimizedGraphBuilder* graph_builder_;
   HGraph* graph_;
   LChunk* chunk_;