diff --git a/cl/_testrt/concat/in.go b/cl/_testrt/concat/in.go
index cb9b44b1..2f0f4a24 100644
--- a/cl/_testrt/concat/in.go
+++ b/cl/_testrt/concat/in.go
@@ -1,9 +1,5 @@
 package main
 
-import (
-	"github.com/goplus/llgo/internal/runtime/c"
-)
-
 func concat(args ...string) (ret string) {
 	for _, v := range args {
 		ret += v
@@ -17,5 +13,5 @@ func info(s string) string {
 
 func main() {
 	result := concat("Hello", " ", "World")
-	c.Fprintf(c.Stderr, c.Str("Hi, %s\n"), c.AllocaCStr(result))
+	println(result)
 }
diff --git a/cl/_testrt/concat/out.ll b/cl/_testrt/concat/out.ll
index bbd1c3f6..ba32c6e5 100644
--- a/cl/_testrt/concat/out.ll
+++ b/cl/_testrt/concat/out.ll
@@ -13,8 +13,6 @@ source_filename = "main"
 @3 = private unnamed_addr constant [6 x i8] c"Hello\00", align 1
 @4 = private unnamed_addr constant [2 x i8] c" \00", align 1
 @5 = private unnamed_addr constant [6 x i8] c"World\00", align 1
-@stderr = external global ptr
-@6 = private unnamed_addr constant [8 x i8] c"Hi, %s\0A\00", align 1
 
 define %"github.com/goplus/llgo/internal/runtime.String" @main.concat(%"github.com/goplus/llgo/internal/runtime.Slice" %0) {
 _llgo_0:
@@ -119,12 +117,8 @@ _llgo_0:
   store i64 3, ptr %21, align 4
   %22 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %18, align 8
   %23 = call %"github.com/goplus/llgo/internal/runtime.String" @main.concat(%"github.com/goplus/llgo/internal/runtime.Slice" %22)
-  %24 = load ptr, ptr @stderr, align 8
-  %25 = extractvalue %"github.com/goplus/llgo/internal/runtime.String" %23, 1
-  %26 = add i64 %25, 1
-  %27 = alloca i8, i64 %26, align 1
-  %28 = call ptr @"github.com/goplus/llgo/internal/runtime.CStrCopy"(ptr %27, %"github.com/goplus/llgo/internal/runtime.String" %23)
-  %29 = call i32 (ptr, ptr, ...) @fprintf(ptr %24, ptr @6, ptr %28)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %23)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
   ret i32 0
 }
 
@@ -136,6 +130,6 @@ declare void @"github.com/goplus/llgo/internal/runtime.init"()
 
 declare ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64)
 
-declare ptr @"github.com/goplus/llgo/internal/runtime.CStrCopy"(ptr, %"github.com/goplus/llgo/internal/runtime.String")
+declare void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String")
 
-declare i32 @fprintf(ptr, ptr, ...)
+declare void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8)
diff --git a/cl/compile_test.go b/cl/compile_test.go
index 48639cf5..130d6d6b 100644
--- a/cl/compile_test.go
+++ b/cl/compile_test.go
@@ -60,10 +60,6 @@ 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")
-}
-
 func TestVar(t *testing.T) {
 	testCompile(t, `package foo
 
diff --git a/internal/abi/llgo_autogen.lla b/internal/abi/llgo_autogen.lla
deleted file mode 100644
index 17d02dd3..00000000
Binary files a/internal/abi/llgo_autogen.lla and /dev/null differ
diff --git a/internal/build/build.go b/internal/build/build.go
index 117b7dc7..d8718a05 100644
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -149,7 +149,13 @@ func Do(args []string, conf *Config) {
 
 	var runtimeFiles []string
 	if needRt {
-		runtimeFiles = allLinkFiles(rt)
+		dpkg := buildAllPkgs(prog, rt[:1], mode, verbose)
+		for _, pkg := range dpkg {
+			if !strings.HasSuffix(pkg.ExportFile, ".ll") {
+				continue
+			}
+			runtimeFiles = append(runtimeFiles, pkg.ExportFile)
+		}
 	}
 	if mode != ModeBuild {
 		nErr := 0
@@ -266,7 +272,7 @@ func linkMainPkg(pkg *packages.Package, pkgs []*aPackage, runtimeFiles []string,
 	needRuntime := false
 	needPyInit := false
 	packages.Visit([]*packages.Package{pkg}, nil, func(p *packages.Package) {
-		if p.ExportFile != "" && !isRuntimePkg(p.PkgPath) { // skip packages that only contain declarations
+		if p.ExportFile != "" { // skip packages that only contain declarations
 			args = appendLinkFiles(args, p.ExportFile)
 			need1, need2 := isNeedRuntimeOrPyInit(p)
 			if !needRuntime {
@@ -445,38 +451,6 @@ func checkFlag(arg string, i *int, verbose *bool, swflags map[string]bool) {
 	}
 }
 
-func allLinkFiles(rt []*packages.Package) (outFiles []string) {
-	outFiles = make([]string, 0, len(rt))
-	packages.Visit(rt, nil, func(p *packages.Package) {
-		pkgPath := p.PkgPath
-		kind, param := cl.PkgKindOf(p.Types)
-		if isRuntimePkg(pkgPath) {
-			exptFile := ""
-			if kind == cl.PkgLinkIR || kind == cl.PkgDeclOnly {
-				exptFile = strings.TrimSpace(param)
-			}
-			llgoPkgLinkFiles(pkgPath, exptFile, func(linkFile string) {
-				outFiles = append(outFiles, linkFile)
-			})
-		}
-	})
-	return
-}
-
-const (
-	pkgAbi      = llgoModPath + "/internal/abi"
-	pkgRuntime  = llgoModPath + "/internal/runtime"
-	pkgRuntimeC = llgoModPath + "/internal/runtime/c"
-)
-
-func isRuntimePkg(pkgPath string) bool {
-	switch pkgPath {
-	case pkgRuntime, pkgAbi, pkgRuntimeC:
-		return true
-	}
-	return false
-}
-
 var (
 	rootDir string
 )
diff --git a/internal/runtime/c/c.go b/internal/runtime/c/c.go
index c16f0f22..63ace390 100644
--- a/internal/runtime/c/c.go
+++ b/internal/runtime/c/c.go
@@ -19,6 +19,10 @@ package c
 import "C"
 import "unsafe"
 
+const (
+	LLGoPackage = "decl"
+)
+
 type (
 	Char    = int8
 	Int     = C.int
@@ -26,15 +30,6 @@ type (
 	FilePtr = unsafe.Pointer
 )
 
-//go:linkname Stdin stdin
-var Stdin FilePtr
-
-//go:linkname Stdout stdout
-var Stdout FilePtr
-
-//go:linkname Stderr stderr
-var Stderr FilePtr
-
 //go:linkname Str llgo.cstr
 func Str(string) *Char
 
diff --git a/internal/runtime/c/c_default.go b/internal/runtime/c/c_default.go
index ac9546ab..cc98cc44 100644
--- a/internal/runtime/c/c_default.go
+++ b/internal/runtime/c/c_default.go
@@ -3,6 +3,13 @@
 
 package c
 
-const (
-	LLGoPackage = "decl: c_default.ll"
-)
+import _ "unsafe"
+
+//go:linkname Stdin __stdinp
+var Stdin FilePtr
+
+//go:linkname Stdout __stdoutp
+var Stdout FilePtr
+
+//go:linkname Stderr __stderrp
+var Stderr FilePtr
diff --git a/internal/runtime/c/c_default.ll b/internal/runtime/c/c_default.ll
deleted file mode 100644
index 53fba4bb..00000000
--- a/internal/runtime/c/c_default.ll
+++ /dev/null
@@ -1,9 +0,0 @@
-; ModuleID = 'github.com/goplus/llgo/internal/runtime/c'
-source_filename = "github.com/goplus/llgo/internal/runtime/c"
-
-@__stderrp = external global ptr
-@__stdinp = external global ptr
-@__stdoutp = external global ptr
-@stdin = alias i8*, i8** @__stdinp
-@stdout = alias i8*, i8** @__stdoutp
-@stderr = alias i8*, i8** @__stderrp
diff --git a/internal/runtime/c/c_linux.go b/internal/runtime/c/c_linux.go
index 940ba7ce..a6a21c39 100644
--- a/internal/runtime/c/c_linux.go
+++ b/internal/runtime/c/c_linux.go
@@ -3,6 +3,13 @@
 
 package c
 
-const (
-	LLGoPackage = "decl: c_linux.ll"
-)
+import _ "unsafe"
+
+//go:linkname Stdin stdin
+var Stdin FilePtr
+
+//go:linkname Stdout stdout
+var Stdout FilePtr
+
+//go:linkname Stderr stderr
+var Stderr FilePtr
diff --git a/internal/runtime/c/c_linux.ll b/internal/runtime/c/c_linux.ll
deleted file mode 100644
index 9addb44e..00000000
--- a/internal/runtime/c/c_linux.ll
+++ /dev/null
@@ -1,2 +0,0 @@
-; ModuleID = 'github.com/goplus/llgo/internal/runtime/c'
-source_filename = "github.com/goplus/llgo/internal/runtime/c"
diff --git a/internal/runtime/llgo_autogen.lla b/internal/runtime/llgo_autogen.lla
deleted file mode 100644
index 7b0dadc2..00000000
Binary files a/internal/runtime/llgo_autogen.lla and /dev/null differ
diff --git a/ssa/cl_test.go b/ssa/cl_test.go
index 209c3bb4..947d2eab 100644
--- a/ssa/cl_test.go
+++ b/ssa/cl_test.go
@@ -41,14 +41,6 @@ func TestFromTestdata(t *testing.T) {
 	cltest.FromDir(t, "", "../cl/_testdata", false)
 }
 
-func TestRuntime(t *testing.T) {
-	cltest.Pkg(t, "github.com/goplus/llgo/internal/runtime", "../internal/runtime/llgo_autogen.ll")
-}
-
-func TestAbi(t *testing.T) {
-	cltest.Pkg(t, "github.com/goplus/llgo/internal/abi", "../internal/abi/llgo_autogen.ll")
-}
-
 func TestMakeInterface(t *testing.T) {
 	prog := ssatest.NewProgram(t, &ssa.Target{GOARCH: "x86"})
 	pkg := prog.NewPackage("foo", "foo")