Implement Function.prototype.toMethod.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index e8c38385ea29e2330345bf8cabc115f6518432f0..a02f6a8315a85db4be67bb671343647f4e577820 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9299,6 +9299,28 @@ void JSFunction::MarkInOptimizationQueue() {
 }
 
 
+Handle<JSFunction> JSFunction::Copy(Handle<JSFunction> function) {

[Toon Verwaest, 2014/08/21 09:02:20]

This method doesn't exactly copy a function anymore. It just creates a new
closure with the same bindings, bound values, and prototype. Please rename to
indicate this.

[Dmitry Lomov (no reviews), 2014/08/21 11:09:11]

Done.

+  Isolate* isolate = function->GetIsolate();
+  Handle<Map> map(function->map());
+  Handle<SharedFunctionInfo> shared(function->shared());
+  Handle<Context> context(function->context());
+  Handle<JSFunction> clone =
+    isolate->factory()->NewFunctionFromSharedFunctionInfo(shared, context);
+
+  if (shared->bound()) {
+    clone->set_function_bindings(function->function_bindings());
+  }
+
+  // In typical case, __proto__ of ``function`` is the default Function
+  // prototype, which means that SetPrototype below is a no-op.
+  // In rare cases when that is not true, we mutate the clone's __proto__.
+  Handle<Object> original_prototype(map->prototype(), isolate);
+  JSObject::SetPrototype(clone, original_prototype, false).Assert();

[Toon Verwaest, 2014/08/21 09:02:20]

JSObject::SetPrototype isn't exactly a no-op right now; it does a whole lot of
stuff. Either manually check here, or there, whether it's the same object.

[Dmitry Lomov (no reviews), 2014/08/21 11:09:11]

Done.

+
+  return clone;
+}
+
+
 void SharedFunctionInfo::AddToOptimizedCodeMap(
     Handle<SharedFunctionInfo> shared,
     Handle<Context> native_context,