diff --git a/cl/_testgo/errors/in.go b/cl/_testgo/errors/in.go
new file mode 100644
index 00000000..ada33367
--- /dev/null
+++ b/cl/_testgo/errors/in.go
@@ -0,0 +1,21 @@
+package main
+
+// New returns an error that formats as the given text.
+// Each call to New returns a distinct error value even if the text is identical.
+func New(text string) error {
+	return &errorString{text}
+}
+
+// errorString is a trivial implementation of error.
+type errorString struct {
+	s string
+}
+
+func (e *errorString) Error() string {
+	return e.s
+}
+
+func main() {
+	err := New("an error")
+	println(err, err.Error())
+}
diff --git a/cl/_testgo/errors/out.ll b/cl/_testgo/errors/out.ll
new file mode 100644
index 00000000..2e203fa4
--- /dev/null
+++ b/cl/_testgo/errors/out.ll
@@ -0,0 +1,213 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+%"github.com/goplus/llgo/internal/runtime.iface" = type { ptr, ptr }
+%"github.com/goplus/llgo/internal/runtime.String" = type { ptr, i64 }
+%main.errorString = type { %"github.com/goplus/llgo/internal/runtime.String" }
+%"github.com/goplus/llgo/internal/abi.StructField" = type { %"github.com/goplus/llgo/internal/runtime.String", ptr, i64, %"github.com/goplus/llgo/internal/runtime.String", i1 }
+%"github.com/goplus/llgo/internal/runtime.Slice" = type { ptr, i64, i64 }
+%"github.com/goplus/llgo/internal/abi.Imethod" = type { %"github.com/goplus/llgo/internal/runtime.String", ptr }
+
+@"main.init$guard" = global ptr null
+@"*main.errorString" = global ptr null
+@"_llgo_iface$Fh8eUJ-Gw4e6TYuajcFIOSCuqSPKAt5nS4ow7xeGXEU" = linkonce global ptr null
+@__llgo_argc = global ptr null
+@__llgo_argv = global ptr null
+@0 = private unnamed_addr constant [9 x i8] c"an error\00", align 1
+@1 = private unnamed_addr constant [2 x i8] c"s\00", align 1
+@2 = private unnamed_addr constant [1 x i8] zeroinitializer, align 1
+@3 = private unnamed_addr constant [5 x i8] c"main\00", align 1
+@4 = private unnamed_addr constant [5 x i8] c"main\00", align 1
+@5 = private unnamed_addr constant [17 x i8] c"main.errorString\00", align 1
+@6 = private unnamed_addr constant [6 x i8] c"Error\00", align 1
+@"_llgo_func$zNDVRsWTIpUPKouNUS805RGX--IV9qVK8B31IZbg5to" = linkonce global ptr null
+@7 = private unnamed_addr constant [5 x i8] c"main\00", align 1
+
+define %"github.com/goplus/llgo/internal/runtime.iface" @main.New(%"github.com/goplus/llgo/internal/runtime.String" %0) {
+_llgo_0:
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 16)
+  %2 = getelementptr inbounds %main.errorString, ptr %1, i32 0, i32 0
+  store %"github.com/goplus/llgo/internal/runtime.String" %0, ptr %2, align 8
+  %3 = load ptr, ptr @"*main.errorString", align 8
+  %4 = load ptr, ptr @"_llgo_iface$Fh8eUJ-Gw4e6TYuajcFIOSCuqSPKAt5nS4ow7xeGXEU", align 8
+  %5 = call ptr @"github.com/goplus/llgo/internal/runtime.NewItab"(ptr %4, ptr %3)
+  %6 = alloca %"github.com/goplus/llgo/internal/runtime.iface", align 8
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %6, i32 0, i32 0
+  store ptr %5, ptr %7, align 8
+  %8 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.iface", ptr %6, i32 0, i32 1
+  store ptr %1, ptr %8, align 8
+  %9 = load %"github.com/goplus/llgo/internal/runtime.iface", ptr %6, align 8
+  ret %"github.com/goplus/llgo/internal/runtime.iface" %9
+}
+
+define %"github.com/goplus/llgo/internal/runtime.String" @"(*main.errorString).Error"(ptr %0) {
+_llgo_0:
+  %1 = getelementptr inbounds %main.errorString, ptr %0, i32 0, i32 0
+  %2 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %1, align 8
+  ret %"github.com/goplus/llgo/internal/runtime.String" %2
+}
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  call void @"main.init$abi"()
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define i32 @main(i32 %0, ptr %1) {
+_llgo_0:
+  store i32 %0, ptr @__llgo_argc, align 4
+  store ptr %1, ptr @__llgo_argv, align 8
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
+  call void @main.init()
+  %2 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %3 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %2, i32 0, i32 0
+  store ptr @0, ptr %3, align 8
+  %4 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %2, i32 0, i32 1
+  store i64 8, ptr %4, align 4
+  %5 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %2, align 8
+  %6 = call %"github.com/goplus/llgo/internal/runtime.iface" @main.New(%"github.com/goplus/llgo/internal/runtime.String" %5)
+  %7 = extractvalue %"github.com/goplus/llgo/internal/runtime.iface" %6, 0
+  %8 = getelementptr ptr, ptr %7, i64 3
+  %9 = load ptr, ptr %8, align 8
+  %10 = extractvalue %"github.com/goplus/llgo/internal/runtime.iface" %6, 1
+  %11 = alloca { ptr, ptr }, align 8
+  %12 = getelementptr inbounds { ptr, ptr }, ptr %11, i32 0, i32 0
+  store ptr %9, ptr %12, align 8
+  %13 = getelementptr inbounds { ptr, ptr }, ptr %11, i32 0, i32 1
+  store ptr %10, ptr %13, align 8
+  %14 = load { ptr, ptr }, ptr %11, align 8
+  %15 = extractvalue { ptr, ptr } %14, 1
+  %16 = extractvalue { ptr, ptr } %14, 0
+  %17 = call %"github.com/goplus/llgo/internal/runtime.String" %16(ptr %15)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintIface"(%"github.com/goplus/llgo/internal/runtime.iface" %6)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 32)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %17)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
+  ret i32 0
+}
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.NewItab"(ptr, ptr)
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintIface"(%"github.com/goplus/llgo/internal/runtime.iface")
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8)
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String")
+
+define void @"main.init$abi"() {
+_llgo_0:
+  %0 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %1 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %0, i32 0, i32 0
+  store ptr @1, ptr %1, align 8
+  %2 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %0, i32 0, i32 1
+  store i64 1, ptr %2, align 4
+  %3 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %0, align 8
+  %4 = call ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64 24)
+  %5 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %6 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %5, i32 0, i32 0
+  store ptr @2, ptr %6, align 8
+  %7 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %5, i32 0, i32 1
+  store i64 0, ptr %7, align 4
+  %8 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %5, align 8
+  %9 = call %"github.com/goplus/llgo/internal/abi.StructField" @"github.com/goplus/llgo/internal/runtime.StructField"(%"github.com/goplus/llgo/internal/runtime.String" %3, ptr %4, i64 0, %"github.com/goplus/llgo/internal/runtime.String" %8, i1 false)
+  %10 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %11 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %10, i32 0, i32 0
+  store ptr @3, ptr %11, align 8
+  %12 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %10, i32 0, i32 1
+  store i64 4, ptr %12, align 4
+  %13 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %10, align 8
+  %14 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocU"(i64 56)
+  %15 = getelementptr %"github.com/goplus/llgo/internal/abi.StructField", ptr %14, i64 0
+  store %"github.com/goplus/llgo/internal/abi.StructField" %9, ptr %15, align 8
+  %16 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
+  %17 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %16, i32 0, i32 0
+  store ptr %14, ptr %17, align 8
+  %18 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %16, i32 0, i32 1
+  store i64 1, ptr %18, align 4
+  %19 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %16, i32 0, i32 2
+  store i64 1, ptr %19, align 4
+  %20 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %16, align 8
+  %21 = call ptr @"github.com/goplus/llgo/internal/runtime.Struct"(%"github.com/goplus/llgo/internal/runtime.String" %13, i64 16, %"github.com/goplus/llgo/internal/runtime.Slice" %20)
+  %22 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %23 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %22, i32 0, i32 0
+  store ptr @4, ptr %23, align 8
+  %24 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %22, i32 0, i32 1
+  store i64 4, ptr %24, align 4
+  %25 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %22, align 8
+  %26 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %27 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %26, i32 0, i32 0
+  store ptr @5, ptr %27, align 8
+  %28 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %26, i32 0, i32 1
+  store i64 16, ptr %28, align 4
+  %29 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %26, align 8
+  %30 = call ptr @"github.com/goplus/llgo/internal/runtime.Named"(%"github.com/goplus/llgo/internal/runtime.String" %25, %"github.com/goplus/llgo/internal/runtime.String" %29, ptr %21, { ptr, i64, i64 } zeroinitializer)
+  %31 = call ptr @"github.com/goplus/llgo/internal/runtime.PointerTo"(ptr %30)
+  store ptr %31, ptr @"*main.errorString", align 8
+  %32 = load ptr, ptr @"_llgo_iface$Fh8eUJ-Gw4e6TYuajcFIOSCuqSPKAt5nS4ow7xeGXEU", align 8
+  %33 = icmp eq ptr %32, null
+  br i1 %33, label %_llgo_1, label %_llgo_2
+
+_llgo_1:                                          ; preds = %_llgo_0
+  %34 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %35 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %34, i32 0, i32 0
+  store ptr @6, ptr %35, align 8
+  %36 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %34, i32 0, i32 1
+  store i64 5, ptr %36, align 4
+  %37 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %34, align 8
+  %38 = load ptr, ptr @"_llgo_func$zNDVRsWTIpUPKouNUS805RGX--IV9qVK8B31IZbg5to", align 8
+  %39 = alloca %"github.com/goplus/llgo/internal/abi.Imethod", align 8
+  %40 = getelementptr inbounds %"github.com/goplus/llgo/internal/abi.Imethod", ptr %39, i32 0, i32 0
+  store %"github.com/goplus/llgo/internal/runtime.String" %37, ptr %40, align 8
+  %41 = getelementptr inbounds %"github.com/goplus/llgo/internal/abi.Imethod", ptr %39, i32 0, i32 1
+  store ptr %38, ptr %41, align 8
+  %42 = load %"github.com/goplus/llgo/internal/abi.Imethod", ptr %39, align 8
+  %43 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocU"(i64 24)
+  %44 = getelementptr %"github.com/goplus/llgo/internal/abi.Imethod", ptr %43, i64 0
+  store %"github.com/goplus/llgo/internal/abi.Imethod" %42, ptr %44, align 8
+  %45 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
+  %46 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %45, i32 0, i32 0
+  store ptr %43, ptr %46, align 8
+  %47 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %45, i32 0, i32 1
+  store i64 1, ptr %47, align 4
+  %48 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %45, i32 0, i32 2
+  store i64 1, ptr %48, align 4
+  %49 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %45, align 8
+  %50 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %51 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %50, i32 0, i32 0
+  store ptr @7, ptr %51, align 8
+  %52 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %50, i32 0, i32 1
+  store i64 4, ptr %52, align 4
+  %53 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %50, align 8
+  %54 = call ptr @"github.com/goplus/llgo/internal/runtime.Interface"(%"github.com/goplus/llgo/internal/runtime.String" %53, %"github.com/goplus/llgo/internal/runtime.Slice" %49)
+  store ptr %54, ptr @"_llgo_iface$Fh8eUJ-Gw4e6TYuajcFIOSCuqSPKAt5nS4ow7xeGXEU", align 8
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.Struct"(%"github.com/goplus/llgo/internal/runtime.String", i64, %"github.com/goplus/llgo/internal/runtime.Slice")
+
+declare %"github.com/goplus/llgo/internal/abi.StructField" @"github.com/goplus/llgo/internal/runtime.StructField"(%"github.com/goplus/llgo/internal/runtime.String", ptr, i64, %"github.com/goplus/llgo/internal/runtime.String", i1)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.AllocU"(i64)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.Named"(%"github.com/goplus/llgo/internal/runtime.String", %"github.com/goplus/llgo/internal/runtime.String", ptr, %"github.com/goplus/llgo/internal/runtime.Slice")
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.PointerTo"(ptr)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.Interface"(%"github.com/goplus/llgo/internal/runtime.String", %"github.com/goplus/llgo/internal/runtime.Slice")
diff --git a/cl/_testgo/struczero/out.ll b/cl/_testgo/struczero/out.ll
index 8299781b..20514bcb 100644
--- a/cl/_testgo/struczero/out.ll
+++ b/cl/_testgo/struczero/out.ll
@@ -20,7 +20,7 @@ source_filename = "main"
 @3 = private unnamed_addr constant [2 x i8] c"F\00", align 1
 @4 = private unnamed_addr constant [1 x i8] zeroinitializer, align 1
 @5 = private unnamed_addr constant [5 x i8] c"main\00", align 1
-@6 = private unnamed_addr constant [5 x i8] c"main\00", align 1
+@6 = private unnamed_addr constant [39 x i8] c"github.com/goplus/llgo/cl/internal/foo\00", align 1
 @7 = private unnamed_addr constant [43 x i8] c"github.com/goplus/llgo/cl/internal/foo.Foo\00", align 1
 @8 = private unnamed_addr constant [3 x i8] c"pb\00", align 1
 @9 = private unnamed_addr constant [1 x i8] zeroinitializer, align 1
@@ -257,7 +257,7 @@ _llgo_1:                                          ; preds = %_llgo_0
   %36 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %35, i32 0, i32 0
   store ptr @6, ptr %36, align 8
   %37 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %35, i32 0, i32 1
-  store i64 4, ptr %37, align 4
+  store i64 38, ptr %37, align 4
   %38 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %35, align 8
   %39 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
   %40 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %39, i32 0, i32 0
diff --git a/cl/_testrt/any/out.ll b/cl/_testrt/any/out.ll
index 612c682e..50a3b9db 100644
--- a/cl/_testrt/any/out.ll
+++ b/cl/_testrt/any/out.ll
@@ -115,7 +115,7 @@ _llgo_0:
 
 _llgo_1:                                          ; preds = %_llgo_0
   %2 = call ptr @"github.com/goplus/llgo/internal/runtime.Basic"(i64 3)
-  %3 = call ptr @"github.com/goplus/llgo/internal/runtime.Pointer"(ptr %2)
+  %3 = call ptr @"github.com/goplus/llgo/internal/runtime.PointerTo"(ptr %2)
   store ptr %3, ptr @"*_llgo_int8", align 8
   br label %_llgo_2
 
@@ -123,4 +123,4 @@ _llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
   ret void
 }
 
-declare ptr @"github.com/goplus/llgo/internal/runtime.Pointer"(ptr)
+declare ptr @"github.com/goplus/llgo/internal/runtime.PointerTo"(ptr)
diff --git a/cl/compile.go b/cl/compile.go
index 7105730d..f5708851 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -558,6 +558,13 @@ func (p *context) compileInstrOrValue(b llssa.Builder, iv instrOrValue, asValue
 	switch v := iv.(type) {
 	case *ssa.Call:
 		cv := v.Call.Value
+		if mthd := v.Call.Method; mthd != nil {
+			o := p.compileValue(b, cv)
+			fn := b.Imethod(o, v.Call.Method)
+			args := p.compileValues(b, v.Call.Args, fnNormal)
+			ret = b.Call(fn, args...)
+			break
+		}
 		kind := p.funcKind(cv)
 		if kind == fnIgnore {
 			return
diff --git a/cl/compile_test.go b/cl/compile_test.go
index 2d601ae2..48639cf5 100644
--- a/cl/compile_test.go
+++ b/cl/compile_test.go
@@ -28,6 +28,10 @@ func testCompile(t *testing.T, src, expected string) {
 	cltest.TestCompileEx(t, src, "foo.go", expected)
 }
 
+func TestFromTestgo(t *testing.T) {
+	cltest.FromDir(t, "", "./_testgo", false)
+}
+
 func TestFromTestpy(t *testing.T) {
 	cltest.FromDir(t, "", "./_testpy", false)
 }
diff --git a/internal/abi/llgo_autogen.lla b/internal/abi/llgo_autogen.lla
index 2eb60535..fefd4872 100644
Binary files a/internal/abi/llgo_autogen.lla and b/internal/abi/llgo_autogen.lla differ
diff --git a/internal/runtime/llgo_autogen.lla b/internal/runtime/llgo_autogen.lla
index 6b788455..349f274c 100644
Binary files a/internal/runtime/llgo_autogen.lla and b/internal/runtime/llgo_autogen.lla differ
diff --git a/internal/runtime/z_closure.go b/internal/runtime/z_closure.go
deleted file mode 100644
index d47818b3..00000000
--- a/internal/runtime/z_closure.go
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package runtime
-
-/*
-import (
-	"unsafe"
-)
-
-// Closure represents a closure.
-type Closure struct {
-	f    unsafe.Pointer
-	data unsafe.Pointer // means no context if data is nil
-}
-
-// NewClosure creates a closure.
-func NewClosure(f, data unsafe.Pointer) Closure {
-	return Closure{f, data}
-}
-
-// ClosureF returns the function of a closure.
-func ClosureF(c Closure) unsafe.Pointer {
-	return c.f
-}
-
-// ClosureData returns the data of a closure.
-func ClosureData(c Closure) unsafe.Pointer {
-	return c.data
-}
-*/
diff --git a/internal/runtime/z_face.go b/internal/runtime/z_face.go
index c7611fd3..149c06c6 100644
--- a/internal/runtime/z_face.go
+++ b/internal/runtime/z_face.go
@@ -43,6 +43,8 @@ type (
 	Itab  = itab
 )
 
+type Imethod = abi.Imethod
+type Method = abi.Method
 type FuncType = abi.FuncType
 type InterfaceType = abi.InterfaceType
 
@@ -54,14 +56,105 @@ func ToEface(i Iface) Eface {
 // -----------------------------------------------------------------------------
 
 const (
-	typeHdrSize         = unsafe.Sizeof(abi.Type{})
-	funcTypeHdrSize     = unsafe.Sizeof(abi.FuncType{})
-	uncommonTypeHdrSize = unsafe.Sizeof(abi.UncommonType{})
-	methodSize          = unsafe.Sizeof(abi.Method{})
-	pointerSize         = unsafe.Sizeof(uintptr(0))
-	itabHdrSize         = unsafe.Sizeof(itab{}) - pointerSize
+	typeHdrSize          = unsafe.Sizeof(abi.Type{})
+	arrayTypeHdrSize     = unsafe.Sizeof(abi.ArrayType{})
+	chanTypeHdrSize      = unsafe.Sizeof(abi.ChanType{})
+	funcTypeHdrSize      = unsafe.Sizeof(abi.FuncType{})
+	interfaceTypeHdrSize = unsafe.Sizeof(abi.InterfaceType{})
+	mapTypeHdrSize       = unsafe.Sizeof(abi.MapType{})
+	ptrTypeHdrSize       = unsafe.Sizeof(abi.PtrType{})
+	sliceTypeHdrSize     = unsafe.Sizeof(abi.SliceType{})
+	structTypeHdrSize    = unsafe.Sizeof(abi.StructType{})
+	uncommonTypeHdrSize  = unsafe.Sizeof(abi.UncommonType{})
+	methodSize           = unsafe.Sizeof(abi.Method{})
+	pointerSize          = unsafe.Sizeof(uintptr(0))
+	itabHdrSize          = unsafe.Sizeof(itab{}) - pointerSize
 )
 
+var hdrSizes = [...]uintptr{
+	arrayTypeHdrSize,
+	chanTypeHdrSize,
+	funcTypeHdrSize,
+	interfaceTypeHdrSize,
+	mapTypeHdrSize,
+	ptrTypeHdrSize,
+	sliceTypeHdrSize,
+	typeHdrSize,
+	structTypeHdrSize,
+}
+
+func hdrSizeOf(kind abi.Kind) uintptr {
+	if kind >= abi.Array && kind <= abi.Struct {
+		return hdrSizes[kind-abi.Array]
+	}
+	return typeHdrSize
+}
+
+// Named returns a named type.
+func Named(pkgPath, name string, underlying *Type, methods []abi.Method) *Type {
+	tflag := underlying.TFlag
+	if tflag&abi.TFlagUncommon != 0 {
+		panic("runtime: underlying type is already named")
+	}
+
+	kind := underlying.Kind()
+	n := len(methods)
+	if kind == abi.Interface {
+		if n > 0 {
+			panic("runtime: interface type cannot have methods")
+		}
+		ret := *underlying.InterfaceType()
+		ret.PkgPath_ = pkgPath
+		ret.Str_ = name
+		return &ret.Type
+	}
+
+	baseSize := hdrSizeOf(kind)
+	extraSize := uintptr(0)
+	if kind == abi.Func {
+		f := underlying.FuncType()
+		extraSize = uintptr(f.In()+f.Out()) * pointerSize
+	}
+
+	size := baseSize + extraSize
+	if n > 0 || pkgPath != "" {
+		size += uncommonTypeHdrSize + uintptr(n)*methodSize
+		tflag |= abi.TFlagUncommon
+	}
+
+	ptr := AllocU(size)
+	c.Memcpy(ptr, unsafe.Pointer(underlying), baseSize)
+
+	ret := (*Type)(ptr)
+	ret.TFlag = tflag | abi.TFlagNamed
+	ret.Str_ = name
+
+	xcount := 0
+	for _, m := range methods {
+		if !m.Exported() {
+			break
+		}
+		xcount++
+	}
+	uncommon := (*abi.UncommonType)(c.Advance(ptr, int(baseSize)))
+	uncommon.PkgPath_ = pkgPath
+	uncommon.Mcount = uint16(n)
+	uncommon.Xcount = uint16(xcount)
+	uncommon.Moff = uint32(uncommonTypeHdrSize + extraSize)
+
+	extraOff := int(baseSize + uncommonTypeHdrSize)
+	if extraSize > 0 {
+		src := c.Advance(unsafe.Pointer(underlying), int(baseSize))
+		dest := c.Advance(unsafe.Pointer(ptr), extraOff)
+		c.Memcpy(dest, src, extraSize)
+		extraOff += int(extraSize)
+	}
+
+	data := (*abi.Method)(c.Advance(ptr, extraOff))
+	copy(unsafe.Slice(data, n), methods)
+	return ret
+}
+
 // Func returns a function type.
 func Func(in, out []*Type, variadic bool) *FuncType {
 	n := len(in) + len(out)
@@ -85,61 +178,8 @@ func Func(in, out []*Type, variadic bool) *FuncType {
 	return ret
 }
 
-// Imethod returns an interface method.
-func Imethod(name string, typ *FuncType) abi.Imethod {
-	return abi.Imethod{
-		Name_: name,
-		Typ_:  typ,
-	}
-}
-
-// Method returns a method.
-func Method(name string, typ *FuncType, ifn, tfn abi.Text) abi.Method {
-	return abi.Method{
-		Name_: name,
-		Mtyp_: typ,
-		Ifn_:  ifn,
-		Tfn_:  tfn,
-	}
-}
-
-// Named returns a named type.
-func Named(pkgPath, name string, underlying *Type, methods []abi.Method) *Type {
-	tflag := underlying.TFlag
-	size := typeHdrSize
-	n := len(methods)
-	if n > 0 || pkgPath != "" {
-		size += uncommonTypeHdrSize + uintptr(n)*methodSize
-		tflag |= abi.TFlagUncommon
-	}
-	ptr := AllocU(size)
-
-	ret := (*Type)(ptr)
-	*ret = *underlying
-	ret.TFlag = tflag | abi.TFlagNamed
-	ret.Str_ = name
-
-	xcount := 0
-	for _, m := range methods {
-		if !m.Exported() {
-			break
-		}
-		xcount++
-	}
-
-	uncommon := (*abi.UncommonType)(c.Advance(ptr, int(typeHdrSize)))
-	uncommon.PkgPath_ = pkgPath
-	uncommon.Mcount = uint16(n)
-	uncommon.Xcount = uint16(xcount)
-	uncommon.Moff = uint32(uncommonTypeHdrSize)
-
-	data := (*abi.Method)(c.Advance(ptr, int(typeHdrSize+uncommonTypeHdrSize)))
-	copy(unsafe.Slice(data, n), methods)
-	return ret
-}
-
 // Interface returns an interface type.
-func Interface(pkgPath string, methods []abi.Imethod) *Type {
+func Interface(pkgPath string, methods []abi.Imethod) *InterfaceType {
 	ret := &abi.InterfaceType{
 		Type: Type{
 			Size_: unsafe.Sizeof(eface{}),
@@ -149,7 +189,7 @@ func Interface(pkgPath string, methods []abi.Imethod) *Type {
 		PkgPath_: pkgPath,
 		Methods:  methods,
 	}
-	return &ret.Type
+	return ret
 }
 
 // NewItab returns a new itab.
@@ -158,7 +198,7 @@ func NewItab(inter *InterfaceType, typ *Type) *Itab {
 	size := itabHdrSize + uintptr(n)*pointerSize
 	ptr := AllocU(size)
 
-	ret := (*Itab)(ptr)
+	ret := (*itab)(ptr)
 	ret.inter = inter
 	ret._type = typ
 	ret.hash = typ.Hash
diff --git a/internal/runtime/z_print.go b/internal/runtime/z_print.go
index 27a47ac7..8edbbb69 100644
--- a/internal/runtime/z_print.go
+++ b/internal/runtime/z_print.go
@@ -69,3 +69,7 @@ func PrintSlice(s Slice) {
 func PrintEface(e Eface) {
 	print("(", e._type, ",", e.data, ")")
 }
+
+func PrintIface(i Iface) {
+	print("(", i.tab, ",", i.data, ")")
+}
diff --git a/internal/runtime/z_type.go b/internal/runtime/z_type.go
index d39ad954..3693a8f4 100644
--- a/internal/runtime/z_type.go
+++ b/internal/runtime/z_type.go
@@ -112,17 +112,22 @@ func Struct(pkgPath string, size uintptr, fields ...abi.StructField) *Type {
 
 // -----------------------------------------------------------------------------
 
-// Pointer returns a pointer type.
-func Pointer(elem *Type) *Type {
-	ret := &abi.PtrType{
-		Type: Type{
-			Size_: unsafe.Sizeof(uintptr(0)),
-			Hash:  uint32(abi.Pointer), // TODO(xsw): hash
-			Kind_: uint8(abi.Pointer),
-		},
-		Elem: elem,
+// PointerTo returns the pointer type with element elem.
+func PointerTo(elem *Type) *Type {
+	ret := elem.PtrToThis_
+	if ret == nil {
+		ptr := &abi.PtrType{
+			Type: Type{
+				Size_: unsafe.Sizeof(uintptr(0)),
+				Hash:  uint32(abi.Pointer), // TODO(xsw): hash
+				Kind_: uint8(abi.Pointer),
+			},
+			Elem: elem,
+		}
+		ret = &ptr.Type
+		elem.PtrToThis_ = ret
 	}
-	return &ret.Type
+	return ret
 }
 
 // -----------------------------------------------------------------------------
diff --git a/ssa/abi/abi.go b/ssa/abi/abi.go
index 48badc0c..e6da942e 100644
--- a/ssa/abi/abi.go
+++ b/ssa/abi/abi.go
@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"go/types"
 	"hash"
+	"log"
 
 	"github.com/goplus/llgo/internal/abi"
 )
@@ -92,7 +93,6 @@ func KindOf(raw types.Type, lvl int, is32Bits bool) (Kind, types.Type, int) {
 
 // Builder is a helper for constructing ABI types.
 type Builder struct {
-	h   hash.Hash
 	buf []byte
 	Pkg string
 }
@@ -106,7 +106,6 @@ func New(pkg string) *Builder {
 
 func (b *Builder) Init(pkg string) {
 	b.Pkg = pkg
-	b.h = sha256.New()
 	b.buf = make([]byte, sha256.Size)
 }
 
@@ -120,11 +119,19 @@ func (b *Builder) TypeName(t types.Type) (ret string, pub bool) {
 		return "*" + ret, pub
 	case *types.Struct:
 		return b.StructName(t)
+	case *types.Signature:
+		return b.FuncName(t), true
 	case *types.Named:
 		o := t.Obj()
 		return TypeName(o), o.Exported()
+	case *types.Interface:
+		if t.Empty() {
+			return "_llgo_any", true
+		}
+		return b.InterfaceName(t)
 	}
-	panic("todo")
+	log.Panicf("todo: %T\n", t)
+	return
 }
 
 // PathOf returns the package path of the specified package.
@@ -150,6 +157,57 @@ func BasicName(t *types.Basic) string {
 	return "_llgo_" + t.Name()
 }
 
+// FuncName returns the ABI type name for the specified function type.
+func (b *Builder) FuncName(t *types.Signature) string {
+	hash := b.funcHash(t)
+	hashStr := base64.RawURLEncoding.EncodeToString(hash)
+	return "_llgo_func$" + hashStr
+}
+
+func (b *Builder) funcHash(t *types.Signature) []byte {
+	h := sha256.New()
+	params, results := t.Params(), t.Results()
+	fmt.Fprintln(h, "func", params.Len(), results.Len(), t.Variadic())
+	b.tuple(h, params)
+	b.tuple(h, results)
+	return h.Sum(b.buf[:0])
+}
+
+func (b *Builder) tuple(h hash.Hash, t *types.Tuple) {
+	n := t.Len()
+	for i := 0; i < n; i++ {
+		v := t.At(i)
+		ft, _ := b.TypeName(v.Type())
+		fmt.Fprintln(h, ft)
+	}
+}
+
+// InterfaceName returns the ABI type name for the specified interface type.
+func (b *Builder) InterfaceName(t *types.Interface) (ret string, pub bool) {
+	hash, private := b.interfaceHash(t)
+	hashStr := base64.RawURLEncoding.EncodeToString(hash)
+	if private {
+		return b.Pkg + ".iface$" + hashStr, false
+	}
+	return "_llgo_iface$" + hashStr, true
+}
+
+func (b *Builder) interfaceHash(t *types.Interface) (ret []byte, private bool) {
+	h := sha256.New()
+	n := t.NumMethods()
+	fmt.Fprintln(h, "interface", n)
+	for i := 0; i < n; i++ {
+		m := t.Method(i)
+		if !m.Exported() {
+			private = true
+		}
+		ft := b.FuncName(m.Type().(*types.Signature))
+		fmt.Fprintln(h, m.Name(), ft)
+	}
+	ret = h.Sum(b.buf[:0])
+	return
+}
+
 // StructName returns the ABI type name for the specified struct type.
 func (b *Builder) StructName(t *types.Struct) (ret string, pub bool) {
 	hash, private := b.structHash(t)
@@ -161,8 +219,7 @@ func (b *Builder) StructName(t *types.Struct) (ret string, pub bool) {
 }
 
 func (b *Builder) structHash(t *types.Struct) (ret []byte, private bool) {
-	h := b.h
-	h.Reset()
+	h := sha256.New()
 	n := t.NumFields()
 	fmt.Fprintln(h, "struct", n)
 	for i := 0; i < n; i++ {
@@ -174,10 +231,7 @@ func (b *Builder) structHash(t *types.Struct) (ret []byte, private bool) {
 		if f.Embedded() {
 			name = "-"
 		}
-		ft, pub := b.TypeName(f.Type())
-		if !pub {
-			private = true
-		}
+		ft, _ := b.TypeName(f.Type())
 		fmt.Fprintln(h, name, ft)
 	}
 	ret = h.Sum(b.buf[:0])
diff --git a/ssa/expr.go b/ssa/expr.go
index 0a4d47ea..bdaa64df 100644
--- a/ssa/expr.go
+++ b/ssa/expr.go
@@ -193,12 +193,6 @@ func (b Builder) Str(v string) (ret Expr) {
 	return Expr{aggregateValue(b.impl, prog.rtString(), data, size), prog.String()}
 }
 
-func (b Builder) pkgName(pkgPath string) Expr {
-	// TODO(xsw): use a global cache
-	// return b.Call(b.Pkg.rtFunc("NewPkgName"), b.Str(pkgPath))
-	return b.Str(pkgPath)
-}
-
 // unsafeString(data *byte, size int) string
 func (b Builder) unsafeString(data, size llvm.Value) Expr {
 	prog := b.Prog
@@ -906,7 +900,7 @@ func (b Builder) InlineCall(fn Expr, args ...Expr) (ret Expr) {
 	return b.Call(fn, args...)
 }
 
-// The Call instruction represents a function or method call.
+// The Call instruction represents a function call.
 //
 // The Call instruction yields the function result if there is exactly
 // one.  Otherwise it returns a tuple, the components of which are
@@ -916,7 +910,6 @@ func (b Builder) InlineCall(fn Expr, args ...Expr) (ret Expr) {
 //
 //	t2 = println(t0, t1)
 //	t4 = t3()
-//	t7 = invoke t5.Println(...t6)
 func (b Builder) Call(fn Expr, args ...Expr) (ret Expr) {
 	if debugInstr {
 		var b bytes.Buffer
@@ -954,7 +947,7 @@ func (b Builder) Call(fn Expr, args ...Expr) (ret Expr) {
 		sig = raw.(*types.Signature)
 		ll = fn.ll
 	default:
-		panic("unreachable")
+		log.Panicf("unreachable: %d(%T)\n", kind, raw)
 	}
 	ret.Type = prog.retType(sig)
 	ret.impl = llvm.CreateCall(b.impl, ll, fn.impl, llvmParamsEx(data, args, sig.Params(), b))
@@ -1077,17 +1070,18 @@ func (b Builder) BuiltinCall(fn string, args ...Expr) (ret Expr) {
 				typ = prog.Float64()
 			case vkSlice:
 				fn = "PrintSlice"
-			case vkPtr, vkFuncPtr, vkFuncDecl:
-				fn = "PrintPointer"
-				typ = prog.VoidPtr()
 			case vkClosure:
 				arg = b.Field(arg, 0)
+				fallthrough
+			case vkPtr, vkFuncPtr, vkFuncDecl:
 				fn = "PrintPointer"
 				typ = prog.VoidPtr()
 			case vkString:
 				fn = "PrintString"
 			case vkEface:
 				fn = "PrintEface"
+			case vkIface:
+				fn = "PrintIface"
 			// case vkComplex:
 			// 	fn = "PrintComplex"
 			default:
diff --git a/ssa/interface.go b/ssa/interface.go
index 217d231a..86fa5762 100644
--- a/ssa/interface.go
+++ b/ssa/interface.go
@@ -55,28 +55,79 @@ func (b Builder) abiTypeOf(t types.Type) Expr {
 		return b.abiStructOf(t)
 	case *types.Named:
 		return b.abiNamedOf(t)
+	case *types.Interface:
+		return b.abiInterfaceOf(t)
+	case *types.Signature:
+		return b.abiFuncOf(t)
 	}
 	panic("todo")
 }
 
+func (b Builder) abiTupleOf(t *types.Tuple) Expr {
+	n := t.Len()
+	prog := b.Prog
+	tSlice := prog.Slice(prog.AbiTypePtr())
+	tuple := make([]Expr, n)
+	for i := 0; i < n; i++ {
+		tuple[i] = b.abiType(t.At(i).Type())
+	}
+	return b.SliceLit(tSlice, tuple...)
+}
+
+// func Func(in, out []*Type, variadic bool)
+func (b Builder) abiFuncOf(sig *types.Signature) Expr {
+	prog := b.Prog
+	pkg := b.Pkg
+	fn := pkg.rtFunc("Func")
+	params := b.abiTupleOf(sig.Params())
+	results := b.abiTupleOf(sig.Results())
+	variadic := prog.Val(sig.Variadic())
+	return b.Call(fn, params, results, variadic)
+}
+
+// Imethod{name string, typ *FuncType}
+func (b Builder) abiImethodOf(m *types.Func) Expr {
+	prog := b.Prog
+	name := b.Str(m.Name())
+	typ := b.abiType(m.Type())
+	return b.aggregateValue(prog.rtType("Imethod"), name.impl, typ.impl)
+}
+
+// func Interface(pkgPath string, methods []abi.Imethod)
+func (b Builder) abiInterfaceOf(t *types.Interface) Expr {
+	prog := b.Prog
+	n := t.NumMethods()
+	methods := make([]Expr, n)
+	for i := 0; i < n; i++ {
+		m := t.Method(i)
+		methods[i] = b.abiImethodOf(m)
+	}
+	pkg := b.Pkg
+	fn := pkg.rtFunc("Interface")
+	pkgPath := pkg.Path()
+	tSlice := lastParamType(prog, fn)
+	methodSlice := b.SliceLit(tSlice, methods...)
+	return b.Call(fn, b.Str(pkgPath), methodSlice)
+}
+
 // func Named(pkgPath, name string, underlying *Type, methods []abi.Method)
 func (b Builder) abiNamedOf(t *types.Named) Expr {
 	under := b.abiTypeOf(t.Underlying())
+	path := abi.PathOf(t.Obj().Pkg())
 	name := NameOf(t)
 
 	prog := b.Prog
 	pkg := b.Pkg
-	pkgPath := b.pkgName(pkg.Path())
 	fn := pkg.rtFunc("Named")
 	tSlice := lastParamType(prog, fn)
 	// TODO(xsw): methods
 	methods := prog.Zero(tSlice)
-	return b.Call(fn, pkgPath, b.Str(name), under, methods)
+	return b.Call(fn, b.Str(path), b.Str(name), under, methods)
 }
 
 func (b Builder) abiPointerOf(t *types.Pointer) Expr {
 	elem := b.abiTypeOf(t.Elem())
-	return b.Call(b.Pkg.rtFunc("Pointer"), elem)
+	return b.Call(b.Pkg.rtFunc("PointerTo"), elem)
 }
 
 // func Struct(pkgPath string, size uintptr, fields []abi.StructField)
@@ -93,7 +144,7 @@ func (b Builder) abiStructOf(t *types.Struct) Expr {
 		off := uintptr(prog.OffsetOf(typ, i))
 		flds[i] = b.structField(sfAbi, prog, f, off, t.Tag(i))
 	}
-	pkgPath := b.pkgName(pkg.Path())
+	pkgPath := b.Str(pkg.Path())
 	tSlice := lastParamType(prog, strucAbi)
 	fldSlice := b.SliceLit(tSlice, flds...)
 	size := prog.IntVal(prog.SizeOf(typ), prog.Uintptr())
@@ -156,6 +207,50 @@ func (b Builder) unsafeEface(t, data llvm.Value) llvm.Value {
 	return aggregateValue(b.impl, b.Prog.rtEface(), t, data)
 }
 
+// unsafeIface(itab *runtime.Itab, data unsafe.Pointer) Eface
+func (b Builder) unsafeIface(itab, data llvm.Value) llvm.Value {
+	return aggregateValue(b.impl, b.Prog.rtIface(), itab, data)
+}
+
+// func NewItab(tintf *InterfaceType, typ *Type) *runtime.Itab
+func (b Builder) newItab(tintf, typ Expr) Expr {
+	return b.Call(b.Pkg.rtFunc("NewItab"), tintf, typ)
+}
+
+func (b Builder) unsafeInterface(rawIntf *types.Interface, t Expr, data llvm.Value) llvm.Value {
+	if rawIntf.Empty() {
+		return b.unsafeEface(t.impl, data)
+	}
+	tintf := b.abiType(rawIntf)
+	itab := b.newItab(tintf, t)
+	return b.unsafeIface(itab.impl, data)
+}
+
+func iMethodOf(rawIntf *types.Interface, method *types.Func) int {
+	name := method.Name()
+	n := rawIntf.NumMethods()
+	for i := 0; i < n; i++ {
+		m := rawIntf.Method(i)
+		if m.Name() == name {
+			// TODO(xsw): check signature
+			return i
+		}
+	}
+	return -1
+}
+
+// Imethod returns closure of an interface method.
+func (b Builder) Imethod(intf Expr, method *types.Func) Expr {
+	prog := b.Prog
+	rawIntf := intf.raw.Type.Underlying().(*types.Interface)
+	i := iMethodOf(rawIntf, method)
+	impl := intf.impl
+	itab := Expr{b.faceItab(impl), prog.VoidPtrPtr()}
+	pfn := b.Advance(itab, prog.IntVal(uint64(i+3), prog.Int()))
+	tclosure := prog.Type(method.Type(), InGo)
+	return b.aggregateValue(tclosure, b.Load(pfn).impl, b.faceData(impl))
+}
+
 // -----------------------------------------------------------------------------
 
 // MakeInterface constructs an instance of an interface type from a
@@ -185,7 +280,7 @@ func (b Builder) MakeInterface(tinter Type, x Expr) (ret Expr) {
 	case abi.Indirect:
 		vptr := b.AllocU(typ)
 		b.Store(vptr, x)
-		return Expr{b.unsafeEface(tabi.impl, vptr.impl), tinter}
+		return Expr{b.unsafeInterface(rawIntf, tabi, vptr.impl), tinter}
 	}
 	ximpl := x.impl
 	if lvl > 0 {
@@ -194,7 +289,7 @@ func (b Builder) MakeInterface(tinter Type, x Expr) (ret Expr) {
 	var u llvm.Value
 	switch kind {
 	case abi.Pointer:
-		return Expr{b.unsafeEface(tabi.impl, ximpl), tinter}
+		return Expr{b.unsafeInterface(rawIntf, tabi, ximpl), tinter}
 	case abi.Integer:
 		tu := prog.Uintptr()
 		u = llvm.CreateIntCast(b.impl, ximpl, tu.ll)
@@ -205,7 +300,7 @@ func (b Builder) MakeInterface(tinter Type, x Expr) (ret Expr) {
 		panic("todo")
 	}
 	data := llvm.CreateIntToPtr(b.impl, u, prog.tyVoidPtr())
-	return Expr{b.unsafeEface(tabi.impl, data), tinter}
+	return Expr{b.unsafeInterface(rawIntf, tabi, data), tinter}
 }
 
 func (b Builder) valFromData(typ Type, data llvm.Value) Expr {
@@ -357,6 +452,10 @@ func (b Builder) faceData(x llvm.Value) llvm.Value {
 	return llvm.CreateExtractValue(b.impl, x, 1)
 }
 
+func (b Builder) faceItab(x llvm.Value) llvm.Value {
+	return llvm.CreateExtractValue(b.impl, x, 0)
+}
+
 func (b Builder) faceAbiType(x Expr) Expr {
 	if x.kind == vkIface {
 		panic("todo")
diff --git a/ssa/package.go b/ssa/package.go
index 5df247db..dd562f4b 100644
--- a/ssa/package.go
+++ b/ssa/package.go
@@ -125,12 +125,14 @@ type aProgram struct {
 
 	rtStringTy llvm.Type
 	rtEfaceTy  llvm.Type
+	rtIfaceTy  llvm.Type
 	rtSliceTy  llvm.Type
 	rtMapTy    llvm.Type
 
 	anyTy     Type
 	voidTy    Type
 	voidPtr   Type
+	voidPPtr  Type
 	boolTy    Type
 	cstrTy    Type
 	cintTy    Type
@@ -149,7 +151,6 @@ type aProgram struct {
 	pyObjPPtr Type
 	abiTyptr  Type
 	abiTypptr Type
-	//efaceTy Type
 
 	pyImpTy    *types.Signature
 	pyNewList  *types.Signature
@@ -256,6 +257,13 @@ func (p Program) rtEface() llvm.Type {
 	return p.rtEfaceTy
 }
 
+func (p Program) rtIface() llvm.Type {
+	if p.rtIfaceTy.IsNil() {
+		p.rtIfaceTy = p.rtType("Iface").ll
+	}
+	return p.rtIfaceTy
+}
+
 func (p Program) rtMap() llvm.Type {
 	if p.rtMapTy.IsNil() {
 		p.rtMapTy = p.rtType("Map").ll
@@ -364,6 +372,13 @@ func (p Program) VoidPtr() Type {
 	return p.voidPtr
 }
 
+func (p Program) VoidPtrPtr() Type {
+	if p.voidPPtr == nil {
+		p.voidPPtr = p.rawType(types.NewPointer(types.Typ[types.UnsafePointer]))
+	}
+	return p.voidPPtr
+}
+
 // Bool returns bool type.
 func (p Program) Bool() Type {
 	if p.boolTy == nil {
diff --git a/ssa/type.go b/ssa/type.go
index 2b1f3608..6f8b2161 100644
--- a/ssa/type.go
+++ b/ssa/type.go
@@ -274,6 +274,7 @@ func (p Program) toType(raw types.Type) Type {
 		if t.Empty() {
 			return &aType{p.rtEface(), typ, vkEface}
 		}
+		return &aType{p.rtIface(), typ, vkIface}
 	case *types.Slice:
 		return &aType{p.rtSlice(), typ, vkSlice}
 	case *types.Map:
diff --git a/ssa/type_cvt.go b/ssa/type_cvt.go
index 9bf505b6..aa578b5d 100644
--- a/ssa/type_cvt.go
+++ b/ssa/type_cvt.go
@@ -66,27 +66,6 @@ func (p Program) FuncDecl(sig *types.Signature, bg Background) Type {
 	return &aType{p.toLLVMFunc(sig), rawType{sig}, vkFuncDecl}
 }
 
-/*
-// cvtCxFunc converts a C extended function type into raw type.
-func cvtCxFunc(sig *types.Signature, recv *types.Var) *types.Signature {
-	if sig.Variadic() {
-			// convert printf-like function type
-			tParams := sig.Params()
-			n := tParams.Len()
-			params := make([]*types.Var, n)
-			n--
-			for i := 0; i < n; i++ {
-				params[i] = tParams.At(i)
-			}
-			params[n] = VArg()
-			sig = types.NewSignatureType(nil, nil, nil, types.NewTuple(params...), sig.Results(), true)
-		panic("todo")
-	}
-	sig = FuncAddCtx(recv, sig)
-	return sig
-}
-*/
-
 // Closure creates a closture type for a function.
 func (p Program) Closure(fn Type) Type {
 	sig := fn.raw.Type.(*types.Signature)