Add a flag to print the time it takes to compile HydrogenCodeStubs.

src/code-stubs-hydrogen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 283 matching lines @@
     stub->InitializeInterfaceDescriptor(isolate, descriptor);
   }
 
   // If we are uninitialized we can use a light-weight stub to enter
   // the runtime that is significantly faster than using the standard
   // stub-failure deopt mechanism.
   if (stub->IsUninitialized() && descriptor->has_miss_handler()) {
     ASSERT(descriptor->stack_parameter_count_ == NULL);
     return stub->GenerateLightweightMissCode(isolate);
   }
+  ElapsedTimer timer;
+  if (FLAG_profile_hydrogen_code_stub_compilation) {
+    timer.Start();

[Yang, 2013/10/02 09:53:53]

You don't want to include GenerateLightweightMissCode?

+  }
   CodeStubGraphBuilder<Stub> builder(isolate, stub);
   LChunk* chunk = OptimizeGraph(builder.CreateGraph());
-  return chunk->Codegen();
+  Handle<Code> code = chunk->Codegen();
+  if (FLAG_profile_hydrogen_code_stub_compilation) {
+    double ms = timer.Elapsed().InMillisecondsF();
+    PrintF("[Lazy compilation of %s took %0.3f ms]\n", *stub->GetName(), ms);
+  }
+  return code;
 }
 
 
 template <>
 HValue* CodeStubGraphBuilder<ToNumberStub>::BuildCodeStub() {
   HValue* value = GetParameter(0);
 
   // Check if the parameter is already a SMI or heap number.
   IfBuilder if_number(this);
   if_number.If<HIsSmiAndBranch>(value);
@@ skipping 810 matching lines @@
   return js_function;
 }
 
 
 Handle<Code> FastNewClosureStub::GenerateCode(Isolate* isolate) {
   return DoGenerateCode(isolate, this);
 }
 
 
 } }  // namespace v8::internal