diff --git a/README.md b/README.md
index 8e2d9c59..0443e077 100644
--- a/README.md
+++ b/README.md
@@ -8,11 +8,23 @@ llgo - A Go compiler based on LLVM
 [![GoDoc](https://pkg.go.dev/badge/github.com/goplus/llgo.svg)](https://pkg.go.dev/github.com/goplus/llgo)
 [![Language](https://img.shields.io/badge/language-Go+-blue.svg)](https://github.com/goplus/gop)
 
-This is a Go compiler based on LLVM in order to better integrate Go with the C ecosystem. It's a subproject of [the Go+ project](https://github.com/goplus/gop).
+This is a Go compiler based on LLVM in order to better integrate Go with the C ecosystem including Python. It's a subproject of [the Go+ project](https://github.com/goplus/gop).
 
 ## C standard libary support
 
-See [github.com/goplus/llgo/c](https://pkg.go.dev/github.com/goplus/llgo/c).
+```go
+package main
+
+import "github.com/goplus/llgo/c"
+
+func main() {
+	c.Printf(c.Str("Hello world\n"))
+}
+```
+
+This is a simple example of calling the C `printf` function to print `Hello world`. Here, `c.Str` is not a function for converting a Go string to a C string, but a built-in instruction supported by llgo for generating a C string constant.
+
+See [github.com/goplus/llgo/c](https://pkg.go.dev/github.com/goplus/llgo/c) for more detials.
 
 
 ## Python support
diff --git a/c/c.go b/c/c.go
index fb70ad1a..6db9e572 100644
--- a/c/c.go
+++ b/c/c.go
@@ -66,7 +66,7 @@ func Memset(s Pointer, c Int, n uintptr) Pointer
 
 // -----------------------------------------------------------------------------
 
-//go:linkname GoStringData github.com/goplus/llgo/internal/runtime.StringData
+//go:linkname GoStringData llgo.stringData
 func GoStringData(string) *Char
 
 // -----------------------------------------------------------------------------
diff --git a/cl/_testdata/print/out.ll b/cl/_testdata/print/out.ll
index fe4ddeac..af0ea398 100644
--- a/cl/_testdata/print/out.ll
+++ b/cl/_testdata/print/out.ll
@@ -624,7 +624,7 @@ _llgo_0:
 _llgo_1:                                          ; preds = %_llgo_3
   %2 = urem i64 %14, 16
   %3 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @10, i64 16)
-  %4 = call ptr @"github.com/goplus/llgo/internal/runtime.StringData"(%"github.com/goplus/llgo/internal/runtime.String" %3)
+  %4 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %3, 0
   %5 = getelementptr inbounds i8, ptr %4, i64 %2
   %6 = load i8, ptr %5, align 1
   %7 = getelementptr inbounds i8, ptr %1, i64 %15
@@ -803,6 +803,4 @@ declare { i64, i1 } @"github.com/goplus/llgo/internal/runtime.CheckI2Int"(%"gith
 
 declare { %"github.com/goplus/llgo/internal/runtime.String", i1 } @"github.com/goplus/llgo/internal/runtime.CheckI2String"(%"github.com/goplus/llgo/internal/runtime.iface", ptr)
 
-declare ptr @"github.com/goplus/llgo/internal/runtime.StringData"(%"github.com/goplus/llgo/internal/runtime.String")
-
 declare ptr @"github.com/goplus/llgo/internal/runtime.SliceData"(%"github.com/goplus/llgo/internal/runtime.Slice")
diff --git a/cl/_testrt/allocstr/out.ll b/cl/_testrt/allocstr/out.ll
index c800e619..5726edc7 100644
--- a/cl/_testrt/allocstr/out.ll
+++ b/cl/_testrt/allocstr/out.ll
@@ -34,7 +34,7 @@ _llgo_0:
   call void @"github.com/goplus/llgo/internal/runtime.init"()
   call void @main.init()
   %2 = call %"github.com/goplus/llgo/internal/runtime.String" @main.hello()
-  %3 = call i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String" %2)
+  %3 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %2, 1
   %4 = add i64 %3, 1
   %5 = alloca i8, i64 %4, align 1
   %6 = call ptr @"github.com/goplus/llgo/internal/runtime.CStrCopy"(ptr %5, %"github.com/goplus/llgo/internal/runtime.String" %2)
@@ -46,8 +46,6 @@ declare %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/ll
 
 declare void @"github.com/goplus/llgo/internal/runtime.init"()
 
-declare i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String")
-
 declare ptr @"github.com/goplus/llgo/internal/runtime.CStrCopy"(ptr, %"github.com/goplus/llgo/internal/runtime.String")
 
 declare i32 @printf(ptr, ...)
diff --git a/cl/_testrt/builtin/out.ll b/cl/_testrt/builtin/out.ll
index 85393f13..9201f246 100644
--- a/cl/_testrt/builtin/out.ll
+++ b/cl/_testrt/builtin/out.ll
@@ -131,14 +131,14 @@ _llgo_0:
   %60 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @0, i64 5)
   call void @main.string_len(%"github.com/goplus/llgo/internal/runtime.String" %60)
   %61 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @1, i64 5)
-  %62 = call i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String" %61)
+  %62 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %61, 1
   %63 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewStringSlice"(%"github.com/goplus/llgo/internal/runtime.String" %61, i64 1, i64 %62)
   call void @main.string_len(%"github.com/goplus/llgo/internal/runtime.String" %63)
   %64 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @2, i64 5)
   %65 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewStringSlice"(%"github.com/goplus/llgo/internal/runtime.String" %64, i64 1, i64 2)
   call void @main.string_len(%"github.com/goplus/llgo/internal/runtime.String" %65)
   %66 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @3, i64 5)
-  %67 = call i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String" %66)
+  %67 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %66, 1
   %68 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewStringSlice"(%"github.com/goplus/llgo/internal/runtime.String" %66, i64 5, i64 %67)
   call void @main.string_len(%"github.com/goplus/llgo/internal/runtime.String" %68)
   ret void
@@ -152,7 +152,7 @@ _llgo_0:
 
 define void @main.string_len(%"github.com/goplus/llgo/internal/runtime.String" %0) {
 _llgo_0:
-  %1 = call i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String" %0)
+  %1 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %0, 1
   call void @main.out(i64 %1)
   ret void
 }
@@ -171,8 +171,6 @@ declare ptr @"github.com/goplus/llgo/internal/runtime.SliceData"(%"github.com/go
 
 declare %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr, i64)
 
-declare i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String")
-
 declare %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewStringSlice"(%"github.com/goplus/llgo/internal/runtime.String", i64, i64)
 
 declare i32 @printf(ptr, ...)
diff --git a/cl/_testrt/concat/out.ll b/cl/_testrt/concat/out.ll
index d343c4e2..e775ef4f 100644
--- a/cl/_testrt/concat/out.ll
+++ b/cl/_testrt/concat/out.ll
@@ -81,7 +81,7 @@ _llgo_0:
   %9 = call %"github.com/goplus/llgo/internal/runtime.Slice" @"github.com/goplus/llgo/internal/runtime.NewSlice3"(ptr %2, i64 16, i64 3, i64 0, i64 3, i64 3)
   %10 = call %"github.com/goplus/llgo/internal/runtime.String" @main.concat(%"github.com/goplus/llgo/internal/runtime.Slice" %9)
   %11 = load ptr, ptr @__stderrp, align 8
-  %12 = call i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String" %10)
+  %12 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %10, 1
   %13 = add i64 %12, 1
   %14 = alloca i8, i64 %13, align 1
   %15 = call ptr @"github.com/goplus/llgo/internal/runtime.CStrCopy"(ptr %14, %"github.com/goplus/llgo/internal/runtime.String" %10)
@@ -103,8 +103,6 @@ declare ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64)
 
 declare %"github.com/goplus/llgo/internal/runtime.Slice" @"github.com/goplus/llgo/internal/runtime.NewSlice3"(ptr, i64, i64, i64, i64, i64)
 
-declare i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String")
-
 declare ptr @"github.com/goplus/llgo/internal/runtime.CStrCopy"(ptr, %"github.com/goplus/llgo/internal/runtime.String")
 
 declare i32 @fprintf(ptr, ptr, ...)
diff --git a/cl/_testrt/index/out.ll b/cl/_testrt/index/out.ll
index b049b8ae..a9af0027 100644
--- a/cl/_testrt/index/out.ll
+++ b/cl/_testrt/index/out.ll
@@ -119,12 +119,12 @@ _llgo_0:
   %61 = load i64, ptr %60, align 4
   %62 = call i32 (ptr, ...) @printf(ptr @3, i64 %61)
   %63 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @5, i64 6)
-  %64 = call ptr @"github.com/goplus/llgo/internal/runtime.StringData"(%"github.com/goplus/llgo/internal/runtime.String" %63)
+  %64 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %63, 0
   %65 = getelementptr inbounds i8, ptr %64, i64 2
   %66 = load i8, ptr %65, align 1
   %67 = call i32 (ptr, ...) @printf(ptr @4, i8 %66)
   %68 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @7, i64 6)
-  %69 = call ptr @"github.com/goplus/llgo/internal/runtime.StringData"(%"github.com/goplus/llgo/internal/runtime.String" %68)
+  %69 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %68, 0
   %70 = getelementptr inbounds i8, ptr %69, i64 1
   %71 = load i8, ptr %70, align 1
   %72 = call i32 (ptr, ...) @printf(ptr @6, i8 %71)
@@ -138,5 +138,3 @@ declare ptr @"github.com/goplus/llgo/internal/runtime.Zeroinit"(ptr, i64)
 declare i32 @printf(ptr, ...)
 
 declare %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr, i64)
-
-declare ptr @"github.com/goplus/llgo/internal/runtime.StringData"(%"github.com/goplus/llgo/internal/runtime.String")
diff --git a/cl/cltest/cltest.go b/cl/cltest/cltest.go
index 436b272e..3b8c60b2 100644
--- a/cl/cltest/cltest.go
+++ b/cl/cltest/cltest.go
@@ -160,7 +160,7 @@ func TestCompileEx(t *testing.T, src any, fname, expected string) {
 		t.Fatal("cl.NewPackage failed:", err)
 	}
 
-	if prog.NeedPyInit() { // call PyInit if needed
+	if prog.NeedPyInit { // call PyInit if needed
 		ret.PyInit()
 	}
 
diff --git a/cl/compile.go b/cl/compile.go
index a6592e2d..998958ec 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -309,6 +309,8 @@ func (p *context) funcOf(fn *ssa.Function) (aFn llssa.Function, pyFn llssa.PyFun
 			ftype = llgoAlloca
 		case "allocaCStr":
 			ftype = llgoAllocaCStr
+		case "stringData":
+			ftype = llgoStringData
 		case "unreachable":
 			ftype = llgoUnreachable
 		default:
@@ -475,6 +477,15 @@ func (p *context) allocaCStr(b llssa.Builder, args []ssa.Value) (ret llssa.Expr)
 	panic("allocaCStr(s string): invalid arguments")
 }
 
+// func stringData(s string) *int8
+func (p *context) stringData(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
+	if len(args) == 1 {
+		s := p.compileValue(b, args[0])
+		return b.StringData(s)
+	}
+	panic("stringData(s string): invalid arguments")
+}
+
 func isPhi(i ssa.Instruction) bool {
 	_, ok := i.(*ssa.Phi)
 	return ok
@@ -482,7 +493,7 @@ func isPhi(i ssa.Instruction) bool {
 
 func (p *context) compilePhis(b llssa.Builder, block *ssa.BasicBlock) int {
 	ret := p.fn.Block(block.Index)
-	b.SetBlock(ret)
+	b.SetBlockEx(ret, llssa.AtEnd)
 	if ninstr := len(block.Instrs); ninstr > 0 {
 		if isPhi(block.Instrs[0]) {
 			n := 1
@@ -569,6 +580,8 @@ func (p *context) compileInstrOrValue(b llssa.Builder, iv instrOrValue, asValue
 				ret = p.alloca(b, args)
 			case llgoAllocaCStr:
 				ret = p.allocaCStr(b, args)
+			case llgoStringData:
+				ret = p.stringData(b, args)
 			case llgoUnreachable: // func unreachable()
 				b.Unreachable()
 			default:
diff --git a/cl/compile_test.go b/cl/compile_test.go
index 9430b561..6f417cbe 100644
--- a/cl/compile_test.go
+++ b/cl/compile_test.go
@@ -52,6 +52,10 @@ func TestFromTestpymath(t *testing.T) {
 	cltest.Pkg(t, ssa.PkgPython+"/math", "../py/math/llgo_autogen.ll")
 }
 
+func TestPython(t *testing.T) {
+	cltest.Pkg(t, ssa.PkgPython, "../py/llgo_autogen.ll")
+}
+
 func TestRuntime(t *testing.T) {
 	cltest.Pkg(t, ssa.PkgRuntime, "../internal/runtime/llgo_autogen.ll")
 }
diff --git a/cl/import.go b/cl/import.go
index 0afc1c0b..11c76ae6 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -317,6 +317,7 @@ const (
 	llgoAllocaCStr  = llgoInstrBase + 3
 	llgoAdvance     = llgoInstrBase + 4
 	llgoIndex       = llgoInstrBase + 5
+	llgoStringData  = llgoInstrBase + 6
 )
 
 func (p *context) funcName(fn *ssa.Function, ignore bool) (*types.Package, string, int) {
diff --git a/internal/build/build.go b/internal/build/build.go
index 38ccc5a8..5a834bc7 100644
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -195,26 +195,29 @@ func buildAllPkgs(prog llssa.Program, initial []*packages.Package, mode Mode, ve
 			// skip packages that only contain declarations
 			// and set no export file
 			pkg.ExportFile = ""
-		case cl.PkgLinkIR, cl.PkgPyModule:
-			// skip packages that don't need to be compiled but need to be linked
+		case cl.PkgLinkIR, cl.PkgLinkExtern, cl.PkgPyModule:
 			pkgPath := pkg.PkgPath
 			if isPkgInLLGo(pkgPath) {
 				pkg.ExportFile = concatPkgLinkFiles(pkgPath)
 			} else {
 				panic("todo")
 			}
-		case cl.PkgLinkExtern:
-			// skip packages that don't need to be compiled but need to be linked with external library
-			linkFile := os.ExpandEnv(strings.TrimSpace(param))
-			dir, lib := filepath.Split(linkFile)
-			command := " -l " + lib
-			if dir != "" {
-				command += " -L " + dir
+			if kind == cl.PkgLinkExtern { // need to be linked with external library
+				linkFile := os.ExpandEnv(strings.TrimSpace(param))
+				dir, lib := filepath.Split(linkFile)
+				command := " -l " + lib
+				if dir != "" {
+					command += " -L " + dir
+				}
+				if isMultiLinkFiles(pkg.ExportFile) {
+					pkg.ExportFile = command + pkg.ExportFile
+				} else {
+					pkg.ExportFile = command + " " + pkg.ExportFile
+				}
 			}
-			pkg.ExportFile = command
 		default:
 			buildPkg(prog, aPkg, mode, verbose)
-			setNeedRuntimeOrPyInit(pkg, prog.NeedRuntime(), prog.NeedPyInit())
+			setNeedRuntimeOrPyInit(pkg, prog.NeedRuntime, prog.NeedPyInit)
 		}
 	}
 	return
diff --git a/internal/llgen/llgen.go b/internal/llgen/llgen.go
index 801a81f0..62278f19 100644
--- a/internal/llgen/llgen.go
+++ b/internal/llgen/llgen.go
@@ -79,7 +79,7 @@ func Gen(pkgPath, inFile string, src any) string {
 	ret, err := cl.NewPackage(prog, ssaPkg, files)
 	check(err)
 
-	if prog.NeedPyInit() { // call PyInit if needed
+	if prog.NeedPyInit { // call PyInit if needed
 		ret.PyInit()
 	}
 
diff --git a/internal/llgen/llgenf.go b/internal/llgen/llgenf.go
index 64a06f55..e7f54dce 100644
--- a/internal/llgen/llgenf.go
+++ b/internal/llgen/llgenf.go
@@ -82,7 +82,7 @@ func GenFrom(fileOrPkg string) string {
 	ret, err := cl.NewPackage(prog, ssaPkg, pkg.Syntax)
 	check(err)
 
-	if prog.NeedPyInit() { // call PyInit if needed
+	if prog.NeedPyInit { // call PyInit if needed
 		ret.PyInit()
 	}
 
diff --git a/internal/pyimport/pyimport.go b/internal/pyimport/pyimport.go
deleted file mode 100644
index 72c23de7..00000000
--- a/internal/pyimport/pyimport.go
+++ /dev/null
@@ -1,38 +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 pyimport
-
-import (
-	_ "unsafe"
-
-	"github.com/goplus/llgo/c"
-	"github.com/goplus/llgo/py"
-)
-
-const (
-	LLGoPackage = "decl"
-)
-
-/*
-func init() {
-	py.Initialize()
-	py.SetProgramName(*c.Argv)
-}
-*/
-
-//go:linkname Module C.PyImport_ImportModule
-func Module(name *c.Char) *py.Module
diff --git a/internal/runtime/llgo_autogen.lla b/internal/runtime/llgo_autogen.lla
index 9620de0b..452cc462 100644
Binary files a/internal/runtime/llgo_autogen.lla and b/internal/runtime/llgo_autogen.lla differ
diff --git a/internal/runtime/z_string.go b/internal/runtime/z_string.go
index ee52e2c0..b137447d 100644
--- a/internal/runtime/z_string.go
+++ b/internal/runtime/z_string.go
@@ -45,16 +45,6 @@ func NewString(data unsafe.Pointer, len int) String {
 	return String{data, len}
 }
 
-// StringLen returns the length of a string.
-func StringLen(s String) int {
-	return s.len
-}
-
-// StringData returns the data pointer of a string.
-func StringData(s String) unsafe.Pointer {
-	return s.data
-}
-
 // StringCat concatenates two strings.
 func StringCat(a, b String) String {
 	n := a.len + b.len
diff --git a/py/_demo/clpy/cleval.go b/py/_demo/clpy/cleval.go
index 13f78b80..5b67bc1e 100644
--- a/py/_demo/clpy/cleval.go
+++ b/py/_demo/clpy/cleval.go
@@ -11,7 +11,7 @@ func main() {
 	code := py.CompileString(c.Str(`print('Hello, World!')`), c.Str(`hello.py`), py.EvalInput)
 	if code != nil {
 		mod := py.ImportModule(c.Str("__main__"))
-		gbl := mod.GetDict()
+		gbl := mod.ModuleGetDict()
 
 		result := py.EvalCode(code, gbl, nil)
 
diff --git a/py/bytes.go b/py/bytes.go
index cd6e257a..1b5277db 100644
--- a/py/bytes.go
+++ b/py/bytes.go
@@ -26,17 +26,17 @@ import (
 
 // String returns a new bytes object from a C string.
 //
-//go:linkname StringFrom C.PyBytes_FromString
-func StringFrom(s *c.Char) *Object
+//go:linkname FromCStr C.PyBytes_FromString
+func FromCStr(s *c.Char) *Object
+
+// FromString returns a new bytes object from a Go string.
+func FromString(s string) *Object {
+	return stringFromStringAndSize(c.GoStringData(s), uintptr(len(s)))
+}
 
 //go:linkname stringFromStringAndSize C.PyBytes_FromStringAndSize
 func stringFromStringAndSize(s *c.Char, size uintptr) *Object
 
-// String returns a new bytes object from a Go string.
-func String(s string) *Object {
-	return stringFromStringAndSize(c.GoStringData(s), uintptr(len(s)))
-}
-
 // CStr returns the content of a bytes object as a C string.
 //
 // llgo:link (*Object).CStr C.PyBytes_AsString
diff --git a/py/llgo_autogen.lla b/py/llgo_autogen.lla
new file mode 100644
index 00000000..79b52437
Binary files /dev/null and b/py/llgo_autogen.lla differ
diff --git a/py/module.go b/py/module.go
index 8dddecbf..59e669c5 100644
--- a/py/module.go
+++ b/py/module.go
@@ -22,18 +22,13 @@ import (
 	"github.com/goplus/llgo/c"
 )
 
-// Module represents a Python module object.
-type Module struct {
-	Object
-}
-
 // -----------------------------------------------------------------------------
 
 // This is a wrapper around py.Import which takes a const char* as an argument
 // instead of an Object.
 //
 //go:linkname ImportModule C.PyImport_ImportModule
-func ImportModule(name *c.Char) *Module
+func ImportModule(name *c.Char) *Object
 
 // This is a higher-level interface that calls the current “import hook function” (with
 // an explicit level of 0, meaning absolute import). It invokes the __import__() function
@@ -43,7 +38,7 @@ func ImportModule(name *c.Char) *Module
 // This function always uses absolute imports.
 //
 //go:linkname Import C.PyImport_Import
-func Import(name *Object) *Module
+func Import(name *Object) *Object
 
 // Return the dictionary object that implements module’s namespace; this object is the same
 // as the __dict__ attribute of the module object. If module is not a module object (or a
@@ -52,7 +47,7 @@ func Import(name *Object) *Module
 // It is recommended extensions use other Module and Object functions rather than directly
 // manipulate a module’s __dict__.
 //
-// llgo:link (*Module).GetDict C.PyModule_GetDict
-func (m *Module) GetDict() *Object { return nil }
+// llgo:link (*Object).ModuleGetDict C.PyModule_GetDict
+func (m *Object) ModuleGetDict() *Object { return nil }
 
 // -----------------------------------------------------------------------------
diff --git a/py/object.go b/py/object.go
index cb973653..6c3d3cc2 100644
--- a/py/object.go
+++ b/py/object.go
@@ -128,7 +128,7 @@ func (o *Object) CallFunctionObjArgs(__llgo_va_list ...any) *Object { return nil
 
 // llgo:link (*Object).CallMethod C.PyObject_CallMethod
 func (o *Object) CallMethod(name *c.Char, format *c.Char, __llgo_va_list ...any) *Object {
-	panic("unreachable")
+	return nil
 }
 
 // llgo:link (*Object).CallMethodObjArgs C.PyObject_CallMethodObjArgs
diff --git a/ssa/decl.go b/ssa/decl.go
index bc6205ec..f5d1b02c 100644
--- a/ssa/decl.go
+++ b/ssa/decl.go
@@ -299,7 +299,7 @@ func (p Package) NewPyFunc(name string, sig *types.Signature, doInit bool) PyFun
 		return v
 	}
 	prog := p.Prog
-	prog.needPyInit = true
+	prog.NeedPyInit = true
 	obj := p.NewVar(name, prog.PyObjectPtrPtr().RawType(), InC)
 	if doInit {
 		obj.Init(prog.Null(obj.Type))
diff --git a/ssa/expr.go b/ssa/expr.go
index 5b4801eb..a97157b8 100644
--- a/ssa/expr.go
+++ b/ssa/expr.go
@@ -607,6 +607,26 @@ func (b Builder) getField(x Expr, idx int) Expr {
 	return Expr{fld, tfld}
 }
 
+// StringData returns the data pointer of a string.
+func (b Builder) StringData(x Expr) Expr {
+	if debugInstr {
+		log.Printf("StringData %v\n", x.impl)
+	}
+	prog := b.Prog
+	ptr := llvm.CreateExtractValue(b.impl, x.impl, 0)
+	return Expr{ptr, prog.CStr()}
+}
+
+// StringLen returns the length of a string.
+func (b Builder) StringLen(x Expr) Expr {
+	if debugInstr {
+		log.Printf("StringLen %v\n", x.impl)
+	}
+	prog := b.Prog
+	ptr := llvm.CreateExtractValue(b.impl, x.impl, 1)
+	return Expr{ptr, prog.Int()}
+}
+
 // The IndexAddr instruction yields the address of the element at
 // index `idx` of collection `x`.  `idx` is an integer expression.
 //
@@ -658,8 +678,7 @@ func (b Builder) Index(x, idx Expr, addr func(Expr) Expr) Expr {
 			panic(fmt.Errorf("invalid operation: cannot index %v", t))
 		}
 		telem = prog.rawType(types.Typ[types.Byte])
-		pkg := b.Func.Pkg
-		ptr = b.InlineCall(pkg.rtFunc("StringData"), x)
+		ptr = b.StringData(x)
 	case *types.Array:
 		telem = prog.Index(x.Type)
 		if addr != nil {
@@ -726,7 +745,7 @@ func (b Builder) Slice(x, low, high, max Expr) (ret Expr) {
 			panic(fmt.Errorf("invalid operation: cannot slice %v", t))
 		}
 		if high.IsNil() {
-			high = b.InlineCall(pkg.rtFunc("StringLen"), x)
+			high = b.StringLen(x)
 		}
 		ret.Type = x.Type
 		ret.impl = b.InlineCall(pkg.rtFunc("NewStringSlice"), x, low, high).impl
@@ -880,7 +899,7 @@ func (b Builder) AllocaCStr(gostr Expr) (ret Expr) {
 		log.Printf("AllocaCStr %v\n", gostr.impl)
 	}
 	pkg := b.Func.Pkg
-	n := b.InlineCall(pkg.rtFunc("StringLen"), gostr)
+	n := b.StringLen(gostr)
 	n1 := b.BinOp(token.ADD, n, b.Prog.Val(1))
 	cstr := b.Alloca(n1)
 	return b.InlineCall(pkg.rtFunc("CStrCopy"), cstr, gostr)
@@ -1278,7 +1297,7 @@ func (b Builder) BuiltinCall(fn string, args ...Expr) (ret Expr) {
 				return b.InlineCall(b.Func.Pkg.rtFunc("SliceLen"), arg)
 			case *types.Basic:
 				if t.Kind() == types.String {
-					return b.InlineCall(b.Func.Pkg.rtFunc("StringLen"), arg)
+					return b.StringLen(arg)
 				}
 			}
 		}
diff --git a/ssa/package.go b/ssa/package.go
index cc730c5c..be863bce 100644
--- a/ssa/package.go
+++ b/ssa/package.go
@@ -141,8 +141,8 @@ type aProgram struct {
 	callNoArgs *types.Signature
 	callOneArg *types.Signature
 
-	needRuntime bool
-	needPyInit  bool
+	NeedRuntime bool
+	NeedPyInit  bool
 }
 
 // A Program presents a program.
@@ -190,21 +190,11 @@ func (p Program) SetRuntime(runtime any) {
 	}
 }
 
-// NeedRuntime returns if the current package needs runtime.
-func (p Program) NeedRuntime() bool {
-	return p.needRuntime
-}
-
-// NeedPyInit returns if the current package needs Python initialization.
-func (p Program) NeedPyInit() bool {
-	return p.needPyInit
-}
-
 func (p Program) runtime() *types.Package {
 	if p.rt == nil {
 		p.rt = p.rtget()
 	}
-	p.needRuntime = true
+	p.NeedRuntime = true
 	return p.rt
 }
 
@@ -269,7 +259,7 @@ func (p Program) NewPackage(name, pkgPath string) Package {
 	stubs := make(map[string]Function)
 	pyfns := make(map[string]PyFunction)
 	pymods := make(map[string]Global)
-	p.needRuntime = false
+	p.NeedRuntime = false
 	// Don't need reset p.needPyInit here
 	// p.needPyInit = false
 	return &aPackage{mod, gbls, fns, stubs, pyfns, pymods, p}
@@ -398,7 +388,7 @@ func (p Package) rtFunc(fnName string) Expr {
 }
 
 func (p Package) pyFunc(fullName string, sig *types.Signature) Expr {
-	p.Prog.needPyInit = true
+	p.Prog.NeedPyInit = true
 	return p.NewFunc(fullName, sig, InC).Expr
 }
 
diff --git a/ssa/ssa_test.go b/ssa/ssa_test.go
index 2e05b4b5..1afddd0d 100644
--- a/ssa/ssa_test.go
+++ b/ssa/ssa_test.go
@@ -199,7 +199,7 @@ source_filename = "foo/bar"
 
 @a = external global {}
 `)
-	if prog.NeedRuntime() {
+	if prog.NeedRuntime {
 		t.Fatal("NeedRuntime?")
 	}
 }
diff --git a/x/sqlite/llgo_autogen.lla b/x/sqlite/llgo_autogen.lla
index e35d151b..cbd7267e 100644
Binary files a/x/sqlite/llgo_autogen.lla and b/x/sqlite/llgo_autogen.lla differ
diff --git a/x/sqlite/sqlite.ll b/x/sqlite/sqlite.ll
index c0e3dac3..2acb9d94 100644
--- a/x/sqlite/sqlite.ll
+++ b/x/sqlite/sqlite.ll
@@ -35,8 +35,8 @@ _llgo_0:
 define { ptr, i32 } @"(*github.com/goplus/llgo/x/sqlite.Sqlite3).Prepare"(ptr %0, %"github.com/goplus/llgo/internal/runtime.String" %1, ptr %2) {
 _llgo_0:
   %3 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 8)
-  %4 = call ptr @"github.com/goplus/llgo/internal/runtime.StringData"(%"github.com/goplus/llgo/internal/runtime.String" %1)
-  %5 = call i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String" %1)
+  %4 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %1, 0
+  %5 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %1, 1
   %6 = trunc i64 %5 to i32
   %7 = call i32 @sqlite3_prepare(ptr %0, ptr %4, i32 %6, ptr %3, ptr %2)
   %8 = load ptr, ptr %3, align 8
@@ -48,8 +48,8 @@ _llgo_0:
 define { ptr, i32 } @"(*github.com/goplus/llgo/x/sqlite.Sqlite3).PrepareV2"(ptr %0, %"github.com/goplus/llgo/internal/runtime.String" %1, ptr %2) {
 _llgo_0:
   %3 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 8)
-  %4 = call ptr @"github.com/goplus/llgo/internal/runtime.StringData"(%"github.com/goplus/llgo/internal/runtime.String" %1)
-  %5 = call i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String" %1)
+  %4 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %1, 0
+  %5 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %1, 1
   %6 = trunc i64 %5 to i32
   %7 = call i32 @sqlite3_prepare_v2(ptr %0, ptr %4, i32 %6, ptr %3, ptr %2)
   %8 = load ptr, ptr %3, align 8
@@ -61,8 +61,8 @@ _llgo_0:
 define { ptr, i32 } @"(*github.com/goplus/llgo/x/sqlite.Sqlite3).PrepareV3"(ptr %0, %"github.com/goplus/llgo/internal/runtime.String" %1, i32 %2, ptr %3) {
 _llgo_0:
   %4 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 8)
-  %5 = call ptr @"github.com/goplus/llgo/internal/runtime.StringData"(%"github.com/goplus/llgo/internal/runtime.String" %1)
-  %6 = call i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String" %1)
+  %5 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %1, 0
+  %6 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %1, 1
   %7 = trunc i64 %6 to i32
   %8 = call i32 @sqlite3_prepare_v3(ptr %0, ptr %5, i32 %7, i32 %2, ptr %4, ptr %3)
   %9 = load ptr, ptr %4, align 8
@@ -92,10 +92,6 @@ declare i32 @sqlite3_open(ptr, ptr)
 
 declare i32 @sqlite3_open_v2(ptr, ptr, i32, ptr)
 
-declare ptr @"github.com/goplus/llgo/internal/runtime.StringData"(%"github.com/goplus/llgo/internal/runtime.String")
-
-declare i64 @"github.com/goplus/llgo/internal/runtime.StringLen"(%"github.com/goplus/llgo/internal/runtime.String")
-
 declare i32 @sqlite3_prepare(ptr, i32, ptr, ptr)
 
 declare i32 @sqlite3_prepare_v2(ptr, i32, ptr, ptr)