diff --git a/.gitignore b/.gitignore
index 18a368ba..ff4e3cde 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,7 +9,7 @@
 *.dylib
 
 test.db
-llgo_autogen.ll
+llgo_autogen*.ll
 stories*.bin
 .DS_Store
 err.log
diff --git a/c/c.go b/c/c.go
index e557e829..da64e03d 100644
--- a/c/c.go
+++ b/c/c.go
@@ -97,13 +97,13 @@ func Qsort(base Pointer, count, elem uintptr, compar func(a, b Pointer) Int)
 
 // -----------------------------------------------------------------------------
 
-//go:linkname Stdin __stdinp
+//go:linkname Stdin llgo_stdin
 var Stdin FilePtr
 
-//go:linkname Stdout __stdoutp
+//go:linkname Stdout llgo_stdout
 var Stdout FilePtr
 
-//go:linkname Stderr __stderrp
+//go:linkname Stderr llgo_stderr
 var Stderr FilePtr
 
 //go:linkname Printf C.printf
diff --git a/cl/_testrt/concat/out.ll b/cl/_testrt/concat/out.ll
index 1ef2685d..9480aeb1 100644
--- a/cl/_testrt/concat/out.ll
+++ b/cl/_testrt/concat/out.ll
@@ -13,7 +13,7 @@ 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
-@__stderrp = external global ptr
+@llgo_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) {
@@ -119,7 +119,7 @@ _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 @__stderrp, align 8
+  %24 = load ptr, ptr @llgo_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
diff --git a/cl/cltest/cltest.go b/cl/cltest/cltest.go
index a0d0b750..04d1036b 100644
--- a/cl/cltest/cltest.go
+++ b/cl/cltest/cltest.go
@@ -26,6 +26,7 @@ import (
 	"log"
 	"os"
 	"path"
+	"path/filepath"
 	"strings"
 	"testing"
 
@@ -74,7 +75,7 @@ func decodeLinkFile(llFile string) (data []byte, err error) {
 		return
 	}
 	defer zipf.Close()
-	f, err := zipf.Open("llgo_autogen.ll")
+	f, err := zipf.Open(filepath.Base(llFile))
 	if err != nil {
 		return
 	}
diff --git a/cl/import.go b/cl/import.go
index 165b2f8c..35ef5317 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -105,6 +105,8 @@ func pkgKind(v string) (int, string) {
 			return PkgLinkExtern, v[5:]
 		} else if strings.HasPrefix(v, "py.") { // "py.<module>"
 			return PkgPyModule, v[3:]
+		} else if strings.HasPrefix(v, "decl:") { // "decl: <param>"
+			return PkgDeclOnly, v[5:]
 		}
 	}
 	return PkgLLGo, ""
diff --git a/internal/build/build.go b/internal/build/build.go
index 32345acd..117b7dc7 100644
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -449,8 +449,13 @@ 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) {
-			llgoPkgLinkFiles(pkgPath, func(linkFile string) {
+			exptFile := ""
+			if kind == cl.PkgLinkIR || kind == cl.PkgDeclOnly {
+				exptFile = strings.TrimSpace(param)
+			}
+			llgoPkgLinkFiles(pkgPath, exptFile, func(linkFile string) {
 				outFiles = append(outFiles, linkFile)
 			})
 		}
@@ -459,13 +464,14 @@ func allLinkFiles(rt []*packages.Package) (outFiles []string) {
 }
 
 const (
-	pkgAbi     = llgoModPath + "/internal/abi"
-	pkgRuntime = llgoModPath + "/internal/runtime"
+	pkgAbi      = llgoModPath + "/internal/abi"
+	pkgRuntime  = llgoModPath + "/internal/runtime"
+	pkgRuntimeC = llgoModPath + "/internal/runtime/c"
 )
 
 func isRuntimePkg(pkgPath string) bool {
 	switch pkgPath {
-	case pkgRuntime, pkgAbi:
+	case pkgRuntime, pkgAbi, pkgRuntimeC:
 		return true
 	}
 	return false
@@ -501,7 +507,7 @@ func concatPkgLinkFiles(pkgPath string) string {
 	var b strings.Builder
 	var ret string
 	var n int
-	llgoPkgLinkFiles(pkgPath, func(linkFile string) {
+	llgoPkgLinkFiles(pkgPath, "", func(linkFile string) {
 		if n == 0 {
 			ret = linkFile
 		} else {
@@ -518,13 +524,16 @@ func concatPkgLinkFiles(pkgPath string) string {
 	return ret
 }
 
-func llgoPkgLinkFiles(pkgPath string, procFile func(linkFile string)) {
+func llgoPkgLinkFiles(pkgPath string, llFile string, procFile func(linkFile string)) {
 	dir := llgoRoot() + pkgPath[len(llgoModPath):] + "/"
-	llFile := dir + "llgo_autogen.ll"
-	llaFile := llFile + "a"
-	zipf, err := zip.OpenReader(llaFile)
+	if llFile == "" {
+		llFile = "llgo_autogen.ll"
+	}
+	llPath := dir + llFile
+	llaPath := llPath + "a"
+	zipf, err := zip.OpenReader(llaPath)
 	if err != nil {
-		procFile(llFile)
+		procFile(llPath)
 		return
 	}
 	defer zipf.Close()
@@ -532,7 +541,7 @@ func llgoPkgLinkFiles(pkgPath string, procFile func(linkFile string)) {
 	for _, f := range zipf.File {
 		procFile(dir + f.Name)
 	}
-	if _, err := os.Stat(llFile); os.IsNotExist(err) {
+	if _, err := os.Stat(llPath); os.IsNotExist(err) {
 		for _, f := range zipf.File {
 			decodeFile(dir+f.Name, f)
 		}
diff --git a/internal/runtime/c/c.go b/internal/runtime/c/c.go
index 3d200e36..a81e95f2 100644
--- a/internal/runtime/c/c.go
+++ b/internal/runtime/c/c.go
@@ -19,10 +19,6 @@ package c
 import "C"
 import "unsafe"
 
-const (
-	LLGoPackage = "decl"
-)
-
 type (
 	Char    = int8
 	Int     = C.int
@@ -30,13 +26,13 @@ type (
 	FilePtr = unsafe.Pointer
 )
 
-//go:linkname Stdin __stdinp
+//go:linkname Stdin llgo_stdin
 var Stdin FilePtr
 
-//go:linkname Stdout __stdoutp
+//go:linkname Stdout llgo_stdout
 var Stdout FilePtr
 
-//go:linkname Stderr __stderrp
+//go:linkname Stderr llgo_stderr
 var Stderr FilePtr
 
 //go:linkname Str llgo.cstr
diff --git a/internal/runtime/c/c_default.go b/internal/runtime/c/c_default.go
new file mode 100644
index 00000000..fd3e7261
--- /dev/null
+++ b/internal/runtime/c/c_default.go
@@ -0,0 +1,8 @@
+//go:build !linux
+// +build !linux
+
+package c
+
+const (
+	LLGoPackage = "decl: stdio_default.ll"
+)
diff --git a/internal/runtime/c/c_default.ll b/internal/runtime/c/c_default.ll
new file mode 100644
index 00000000..208dd270
--- /dev/null
+++ b/internal/runtime/c/c_default.ll
@@ -0,0 +1,9 @@
+; 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
+@llgo_stdin = alias i8*, i8** @__stdinp
+@llgo_stdout = alias i8*, i8** @__stdoutp
+@llgo_stderr = alias i8*, i8** @__stderrp
diff --git a/internal/runtime/c/c_linux.go b/internal/runtime/c/c_linux.go
new file mode 100644
index 00000000..6f22e8de
--- /dev/null
+++ b/internal/runtime/c/c_linux.go
@@ -0,0 +1,8 @@
+//go:build linux
+// +build linux
+
+package c
+
+const (
+	LLGoPackage = "decl: stdio_linux.ll"
+)
diff --git a/internal/runtime/c/c_linux.ll b/internal/runtime/c/c_linux.ll
new file mode 100644
index 00000000..4fc23ebf
--- /dev/null
+++ b/internal/runtime/c/c_linux.ll
@@ -0,0 +1,9 @@
+; ModuleID = 'github.com/goplus/llgo/internal/runtime/c'
+source_filename = "github.com/goplus/llgo/internal/runtime/c"
+
+@stderr = external global ptr
+@stdin = external global ptr
+@stdout = external global ptr
+@llgo_stdin = alias i8*, i8** @stdin
+@llgo_stdout = alias i8*, i8** @stdout
+@llgo_stderr = alias i8*, i8** @stderr
diff --git a/internal/runtime/llgo_autogen.lla b/internal/runtime/llgo_autogen.lla
index 4cb3ec4a..64fd5020 100644
Binary files a/internal/runtime/llgo_autogen.lla and b/internal/runtime/llgo_autogen.lla differ