[runtime] Add function for printing type profile.

src/runtime/runtime-test.cc

Index: src/runtime/runtime-test.cc
diff --git a/src/runtime/runtime-test.cc b/src/runtime/runtime-test.cc
index 2a34d9c03130ba3a9784c5eeaa6bca6a76feb132..0c92f2d4928e2f20ea331984d996ce8f7daaa629 100644
--- a/src/runtime/runtime-test.cc
+++ b/src/runtime/runtime-test.cc
@@ -156,6 +156,38 @@ RUNTIME_FUNCTION(Runtime_IsConcurrentRecompilationSupported) {
       isolate->concurrent_recompilation_enabled());
 }
 
+RUNTIME_FUNCTION(Runtime_PrintTypeProfile) {
+  HandleScope scope(isolate);

[Yang, 2017/03/20 08:48:45]

Let's DCHECK that args.length() is 1.

[Franzi, 2017/03/20 10:09:56]

Done.

+  if (!FLAG_type_profile) {
+    return isolate->heap()->undefined_value();
+  }
+
+  CONVERT_ARG_HANDLE_CHECKED(Object, function_object, 0);
+  if (!function_object->IsJSFunction()) {

[Yang, 2017/03/20 08:48:45]

You can omit this type check if you define function_object to be JSFunction
above.

[Franzi, 2017/03/20 10:09:56]

Done.

+    return isolate->heap()->undefined_value();
+  }
+  Handle<JSFunction> function = Handle<JSFunction>::cast(function_object);
+
+  if (function->has_feedback_vector()) {
+    FeedbackVector* vector = function->feedback_vector();
+
+    Object* function_name = vector->shared_function_info()->name();
+    PrintF("Function: %s\n", String::cast(function_name)->ToCString().get());
+
+    FeedbackMetadataIterator iter(vector->metadata());
+    while (iter.HasNext()) {
+      FeedbackSlot slot = iter.Next();
+      FeedbackSlotKind kind = iter.kind();
+      if (kind == FeedbackSlotKind::kTypeProfile) {
+        CollectTypeProfileNexus nexus(vector, slot);
+        nexus.Print();
+        PrintF("\n");
+        return isolate->heap()->undefined_value();

[Yang, 2017/03/20 08:48:45]

Do you really want to return after the first TypeProfile slot?

[Franzi, 2017/03/20 10:09:56]

Yes! Sorry, I discussed offline with Michi that we'll use 1 slot for all type
information.

+      }
+    }
+  }
+  return isolate->heap()->undefined_value();
+}
 
 RUNTIME_FUNCTION(Runtime_OptimizeFunctionOnNextCall) {
   HandleScope scope(isolate);