diff --git a/cl/_testcgo/strlen/out.ll b/cl/_testcgo/strlen/out.ll
index e69de29b..aa7b8522 100644
--- a/cl/_testcgo/strlen/out.ll
+++ b/cl/_testcgo/strlen/out.ll
@@ -0,0 +1,41 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+@"main.init$guard" = global ptr null
+@main._Cgo_always_false = global ptr null
+@main.format = global ptr null
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$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
+  store i8 72, ptr @main.format, align 1
+  store i8 101, ptr getelementptr inbounds (i8, ptr @main.format, i64 1), align 1
+  store i8 108, ptr getelementptr inbounds (i8, ptr @main.format, i64 2), align 1
+  store i8 108, ptr getelementptr inbounds (i8, ptr @main.format, i64 3), align 1
+  store i8 111, ptr getelementptr inbounds (i8, ptr @main.format, i64 4), align 1
+  store i8 32, ptr getelementptr inbounds (i8, ptr @main.format, i64 5), align 1
+  store i8 37, ptr getelementptr inbounds (i8, ptr @main.format, i64 6), align 1
+  store i8 100, ptr getelementptr inbounds (i8, ptr @main.format, i64 7), align 1
+  store i8 10, ptr getelementptr inbounds (i8, ptr @main.format, i64 8), align 1
+  store i8 0, ptr getelementptr inbounds (i8, ptr @main.format, i64 9), align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+declare void @printf(ptr, ...)
+
+declare i32 @strlen(ptr)
+
+define void @main() {
+_llgo_0:
+  call void @main.init()
+  %0 = call i32 @strlen(ptr @main.format)
+  call void (ptr, ...) @printf(ptr @main.format, i32 %0)
+  ret void
+}
diff --git a/cl/compile.go b/cl/compile.go
index 6f435e8c..a499dbe8 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -25,6 +25,7 @@ import (
 	"log"
 	"os"
 	"sort"
+	"strings"
 
 	llssa "github.com/goplus/llgo/ssa"
 	"golang.org/x/tools/go/ssa"
@@ -57,7 +58,7 @@ func SetDebug(dbgFlags dbgFlags) {
 const (
 	fnNormal = iota
 	fnHasVArg
-	fnUnsafeInit
+	fnIgnore
 )
 
 func funcKind(vfn ssa.Value) int {
@@ -65,8 +66,8 @@ func funcKind(vfn ssa.Value) int {
 		params := fn.Signature.Params()
 		n := params.Len()
 		if n == 0 {
-			if fn.Name() == "init" && fn.Pkg.Pkg.Path() == "unsafe" {
-				return fnUnsafeInit
+			if fn.Name() == "init" && ignorePkgInit(fn.Pkg.Pkg.Path()) {
+				return fnIgnore
 			}
 		} else {
 			last := params.At(n - 1)
@@ -78,6 +79,32 @@ func funcKind(vfn ssa.Value) int {
 	return fnNormal
 }
 
+func ignorePkgInit(pkgPath string) bool {
+	switch pkgPath {
+	case "unsafe", "syscall", "runtime/cgo":
+		return true
+	}
+	return false
+}
+
+func ignoreFunc(name string, fn *ssa.Function) bool {
+	/* TODO(xsw): confirm this is not needed more
+	if name == "unsafe.init" {
+		return true
+	}
+	*/
+	fnName := fn.Name()
+	if strings.HasPrefix(fnName, "_Cgo_") {
+		return true
+	}
+	const runtime = "runtime"
+	if strings.HasPrefix(name, runtime) {
+		left := name[len(runtime):]
+		return strings.HasPrefix(left, ".cgo") || strings.HasPrefix(left, "/cgo")
+	}
+	return false
+}
+
 // -----------------------------------------------------------------------------
 
 type none = struct{}
@@ -137,14 +164,12 @@ func (p *context) compileGlobal(pkg llssa.Package, gbl *ssa.Global) {
 func (p *context) compileFunc(pkg llssa.Package, pkgTypes *types.Package, f *ssa.Function) {
 	sig := f.Signature
 	name := p.funcName(pkgTypes, f)
-	/* TODO(xsw): confirm this is not needed more
-	if name == "unsafe.init" {
-		return
-	}
-	*/
 	if debugInstr {
 		log.Println("==> NewFunc", name, "type:", sig.Recv(), sig)
 	}
+	if ignoreFunc(name, f) {
+		return
+	}
 	fn := pkg.NewFunc(name, sig)
 	p.inits = append(p.inits, func() {
 		p.fn = fn
@@ -229,7 +254,7 @@ func (p *context) compileInstrAndValue(b llssa.Builder, iv instrAndValue) (ret l
 		call := v.Call
 		cv := call.Value
 		kind := funcKind(cv)
-		if kind == fnUnsafeInit {
+		if kind == fnIgnore {
 			return
 		}
 		if debugGoSSA {
diff --git a/cl/compile_test.go b/cl/compile_test.go
index 49759d2f..9e832a3c 100644
--- a/cl/compile_test.go
+++ b/cl/compile_test.go
@@ -27,8 +27,12 @@ func testCompile(t *testing.T, src, expected string) {
 	cltest.TestCompileEx(t, src, "foo.go", expected)
 }
 
+func TestFromTestcgo(t *testing.T) {
+	cltest.FromDir(t, "strlen", "./_testcgo", true)
+}
+
 func TestFromTestdata(t *testing.T) {
-	cltest.FromDir(t, "apkg", "./_testdata", false)
+	cltest.FromDir(t, "", "./_testdata", false)
 }
 
 func TestVar(t *testing.T) {
diff --git a/cl/import.go b/cl/import.go
index 5f2faf45..4abc9337 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -120,10 +120,11 @@ func fullName(pkg *types.Package, name string) string {
 // method: (pkg.T).name
 func funcName(pkg *types.Package, fn *ssa.Function) string {
 	sig := fn.Signature
+	name := fn.Name()
 	if recv := sig.Recv(); recv != nil {
-		return "(" + recv.Type().String() + ")." + fn.Name()
+		return "(" + recv.Type().String() + ")." + name
 	}
-	ret := fullName(pkg, fn.Name())
+	ret := fullName(pkg, name)
 	if ret == "main.main" {
 		ret = "main"
 	}
diff --git a/internal/llgen/llgenf.go b/internal/llgen/llgenf.go
index e447723a..9eca9f8d 100644
--- a/internal/llgen/llgenf.go
+++ b/internal/llgen/llgenf.go
@@ -22,6 +22,7 @@ import (
 	"github.com/goplus/llgo/cl"
 	"golang.org/x/tools/go/packages"
 	"golang.org/x/tools/go/ssa"
+	"golang.org/x/tools/go/ssa/ssautil"
 
 	llssa "github.com/goplus/llgo/ssa"
 )
@@ -40,10 +41,11 @@ func GenFromFile(inFile string) string {
 	initial, err := packages.Load(cfg, inFile)
 	check(err)
 
+	_, pkgs := ssautil.AllPackages(initial, ssa.SanityCheckFunctions)
+
 	pkg := initial[0]
-	fset := pkg.Fset
-	ssaProg := ssa.NewProgram(fset, ssa.SanityCheckFunctions)
-	ssaPkg := ssaProg.CreatePackage(pkg.Types, pkg.Syntax, pkg.TypesInfo, true)
+	ssaPkg := pkgs[0]
+	ssaPkg.Build()
 
 	prog := llssa.NewProgram(nil)
 	ret, err := cl.NewPackage(prog, ssaPkg, pkg.Syntax)