Implement Function.prototype.toMethod.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index e8c38385ea29e2330345bf8cabc115f6518432f0..e79bc9d6d8c3f95153ce43d19c47a72c2ada4534 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9299,6 +9299,30 @@ void JSFunction::MarkInOptimizationQueue() {
 }
 
 
+Handle<JSFunction> JSFunction::CloneClosure(Handle<JSFunction> function) {
+  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.

[Toon Verwaest, 2014/08/21 11:32:28]

Now this comment is a bit off

+  // In rare cases when that is not true, we mutate the clone's __proto__.
+  Handle<Object> original_prototype(map->prototype(), isolate);
+  if (*original_prototype != clone->map()->prototype()) {
+    JSObject::SetPrototype(clone, original_prototype, false).Assert();
+  }
+
+  return clone;
+}
+
+
 void SharedFunctionInfo::AddToOptimizedCodeMap(
     Handle<SharedFunctionInfo> shared,
     Handle<Context> native_context,