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

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/25693003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17071 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/code-stubs-hydrogen.cc

@@ -301,9 +301,18 @@ static Handle<Code> DoGenerateCode(Isolate* isolate, Stub* stub) {
     ASSERT(descriptor->stack_parameter_count_ == NULL);
     return stub->GenerateLightweightMissCode(isolate);
   }
+  ElapsedTimer timer;
+  if (FLAG_profile_hydrogen_code_stub_compilation) {
+    timer.Start();
+  }
   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;
 }
 
 

src/code-stubs.h

@@ -200,6 +200,9 @@ class CodeStub BASE_EMBEDDED {
 
   virtual void PrintName(StringStream* stream);
 
+  // Returns a name for logging/debugging purposes.
+  SmartArrayPointer<const char> GetName();
+
  protected:
   static bool CanUseFPRegisters();
 
@@ -211,8 +214,6 @@ class CodeStub BASE_EMBEDDED {
   // a fixed (non-moveable) code object.
   virtual bool NeedsImmovableCode() { return false; }
 
-  // Returns a name for logging/debugging purposes.
-  SmartArrayPointer<const char> GetName();
   virtual void PrintBaseName(StringStream* stream);
   virtual void PrintState(StringStream* stream) { }
 

src/flag-definitions.h

@@ -621,6 +621,11 @@ DEFINE_string(testing_serialization_file, "/tmp/serdes",
 DEFINE_string(extra_code, NULL, "A filename with extra code to be included in"
                   " the snapshot (mksnapshot only)")
 
+// code-stubs-hydrogen.cc
+DEFINE_bool(profile_hydrogen_code_stub_compilation,
+            false,
+            "Print the time it takes to lazily compile hydrogen code stubs.")
+
 //
 // Dev shell flags
 //
@@ -801,6 +806,7 @@ DEFINE_bool(test_primary_stub_cache,
             false,
             "test primary stub cache by disabling the secondary one")
 
+
 // codegen-ia32.cc / codegen-arm.cc
 DEFINE_bool(print_code, false, "print generated code")
 DEFINE_bool(print_opt_code, false, "print optimized code")