diff --git a/chore/llgen/llgen.go b/chore/llgen/llgen.go
index 50e9a89e..33fb48e7 100644
--- a/chore/llgen/llgen.go
+++ b/chore/llgen/llgen.go
@@ -21,14 +21,19 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/goplus/llgo/internal/build"
 	"github.com/goplus/llgo/internal/llgen"
 )
 
+var (
+	abi = flag.Int("abi", 0, "ABI mode (default 0). 0 = none, 1 = cfunc, 2 = allfunc.")
+)
+
 func main() {
 	flag.Parse()
 	if len(flag.Args()) != 1 {
 		fmt.Fprintln(os.Stderr, "Usage: llgen [flags] <pkg>")
 		return
 	}
-	llgen.SmartDoFile(flag.Args()[0])
+	llgen.SmartDoFileEx(flag.Args()[0], build.AbiMode(*abi))
 }
diff --git a/internal/llgen/llgenf.go b/internal/llgen/llgenf.go
index 55e5d5af..4ac61b50 100644
--- a/internal/llgen/llgenf.go
+++ b/internal/llgen/llgenf.go
@@ -27,12 +27,12 @@ import (
 )
 
 func GenFrom(fileOrPkg string) string {
-	pkg, err := genFrom(fileOrPkg)
+	pkg, err := genFrom(fileOrPkg, 0)
 	check(err)
 	return pkg.LPkg.String()
 }
 
-func genFrom(pkgPath string) (build.Package, error) {
+func genFrom(pkgPath string, abiMode build.AbiMode) (build.Package, error) {
 	oldDbg := os.Getenv("LLGO_DEBUG")
 	oldDbgSyms := os.Getenv("LLGO_DEBUG_SYMBOLS")
 	dbg := isDbgSymEnabled(filepath.Join(pkgPath, "flags.txt"))
@@ -46,8 +46,9 @@ func genFrom(pkgPath string) (build.Package, error) {
 	}()
 
 	conf := &build.Config{
-		Mode:   build.ModeGen,
-		AppExt: build.DefaultAppExt(runtime.GOOS),
+		Mode:    build.ModeGen,
+		AbiMode: abiMode,
+		AppExt:  build.DefaultAppExt(runtime.GOOS),
 	}
 	pkgs, err := build.Do([]string{pkgPath}, conf)
 	if err != nil {
@@ -77,7 +78,11 @@ func isDbgSymEnabled(flagsFile string) bool {
 }
 
 func SmartDoFile(pkgPath string) {
-	pkg, err := genFrom(pkgPath)
+	SmartDoFileEx(pkgPath, 0)
+}
+
+func SmartDoFileEx(pkgPath string, abiMode build.AbiMode) {
+	pkg, err := genFrom(pkgPath, abiMode)
 	check(err)
 
 	const autgenFile = "llgo_autogen.ll"