diff --git a/cl/compile.go b/cl/compile.go
index 794359187..ab52b6172 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -208,6 +208,9 @@ type Config struct {
 
 	// Outline = true means to skip compiling function bodies.
 	Outline bool
+
+	// AddMarkStmt = true means to add const __gop_autogen__ = true.
+	AddMarkStmt bool
 }
 
 type nodeInterp struct {
@@ -498,6 +501,11 @@ func NewPackage(pkgPath string, pkg *ast.Package, conf *Config) (p *gox.Package,
 		}()
 	}
 	p = gox.NewPackage(pkgPath, pkg.Name, confGox)
+
+	if conf.AddMarkStmt {
+		p.CB().NewConstStart(nil, "__gop_autogen__").Val(true).EndInit(1)
+	}
+
 	ctx.cpkgs = cpackages.NewImporter(&cpackages.Config{
 		Pkg: p, LookupPub: conf.LookupPub,
 	})
diff --git a/load.go b/load.go
index f5706c99b..fe3693936 100644
--- a/load.go
+++ b/load.go
@@ -192,6 +192,7 @@ func LoadDir(dir string, conf *Config, genTestPkg bool, promptGenGo ...bool) (ou
 		Importer:     imp,
 		LookupClass:  mod.LookupClass,
 		LookupPub:    c2go.LookupPub(mod),
+		AddMarkStmt:  true,
 	}
 
 	for name, pkg := range pkgs {
@@ -277,6 +278,7 @@ func LoadFiles(dir string, files []string, conf *Config) (out *gox.Package, err
 			Importer:     imp,
 			LookupClass:  mod.LookupClass,
 			LookupPub:    c2go.LookupPub(mod),
+			AddMarkStmt:  true,
 		}
 		out, err = cl.NewPackage("", pkg, clConf)
 		if err != nil {