diff --git a/README.md b/README.md
index cd20a497..d4ed6535 100644
--- a/README.md
+++ b/README.md
@@ -185,6 +185,17 @@ Here are some examples related to Go syntax:
 * [goroutine](_demo/goroutine/goroutine.go): goroutine demo
 
 
+### Garbage Collection (GC)
+
+By default, LLGo implements `gc` based on [bdwgc](https://www.hboehm.info/gc/).
+
+However, you can disable gc by specifying the `nogc` tag. For example:
+
+```sh
+llgo run -tags nogc .
+```
+
+
 ## Go packages support
 
 Here are the Go packages that can be imported correctly:
diff --git a/c/c_default.go b/c/c_default.go
index cc98cc44..45286fe9 100644
--- a/c/c_default.go
+++ b/c/c_default.go
@@ -1,6 +1,22 @@
 //go:build !linux
 // +build !linux
 
+/*
+ * 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 c
 
 import _ "unsafe"
diff --git a/c/c_linux.go b/c/c_linux.go
index a6a21c39..70cc9bea 100644
--- a/c/c_linux.go
+++ b/c/c_linux.go
@@ -1,6 +1,22 @@
 //go:build linux
 // +build linux
 
+/*
+ * 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 c
 
 import _ "unsafe"
diff --git a/internal/runtime/bdwgc/bdwgc.go b/internal/runtime/bdwgc/bdwgc.go
index 907b3217..6b947962 100644
--- a/internal/runtime/bdwgc/bdwgc.go
+++ b/internal/runtime/bdwgc/bdwgc.go
@@ -1,3 +1,19 @@
+/*
+ * 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 bdwgc
 
 import (
diff --git a/internal/runtime/c/c_default.go b/internal/runtime/c/c_default.go
index cc98cc44..45286fe9 100644
--- a/internal/runtime/c/c_default.go
+++ b/internal/runtime/c/c_default.go
@@ -1,6 +1,22 @@
 //go:build !linux
 // +build !linux
 
+/*
+ * 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 c
 
 import _ "unsafe"
diff --git a/internal/runtime/c/c_linux.go b/internal/runtime/c/c_linux.go
index a6a21c39..70cc9bea 100644
--- a/internal/runtime/c/c_linux.go
+++ b/internal/runtime/c/c_linux.go
@@ -1,6 +1,22 @@
 //go:build linux
 // +build linux
 
+/*
+ * 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 c
 
 import _ "unsafe"
diff --git a/internal/runtime/error.go b/internal/runtime/error.go
deleted file mode 100644
index 8f46aff4..00000000
--- a/internal/runtime/error.go
+++ /dev/null
@@ -1,27 +0,0 @@
-package runtime
-
-type errorString string
-
-func (e errorString) RuntimeError() {}
-
-func (e errorString) Error() string {
-	return "runtime error: " + string(e)
-}
-
-func AssertRuntimeError(b bool, msg string) {
-	if b {
-		panic(errorString(msg).Error())
-	}
-}
-
-func AssertNegativeShift(b bool) {
-	if b {
-		panic(errorString("negative shift amount").Error())
-	}
-}
-
-func AssertIndexRange(b bool) {
-	if b {
-		panic(errorString("index out of range").Error())
-	}
-}
diff --git a/internal/runtime/z_error.go b/internal/runtime/z_error.go
new file mode 100644
index 00000000..e08d8f8b
--- /dev/null
+++ b/internal/runtime/z_error.go
@@ -0,0 +1,43 @@
+/*
+ * 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
+
+type errorString string
+
+func (e errorString) RuntimeError() {}
+
+func (e errorString) Error() string {
+	return "runtime error: " + string(e)
+}
+
+func AssertRuntimeError(b bool, msg string) {
+	if b {
+		panic(errorString(msg).Error())
+	}
+}
+
+func AssertNegativeShift(b bool) {
+	if b {
+		panic(errorString("negative shift amount").Error())
+	}
+}
+
+func AssertIndexRange(b bool) {
+	if b {
+		panic(errorString("index out of range").Error())
+	}
+}
diff --git a/internal/runtime/z_gc.go b/internal/runtime/z_gc.go
new file mode 100644
index 00000000..3eb1c856
--- /dev/null
+++ b/internal/runtime/z_gc.go
@@ -0,0 +1,38 @@
+//go:build !nogc
+// +build !nogc
+
+/*
+ * 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"
+
+	"github.com/goplus/llgo/internal/runtime/bdwgc"
+	"github.com/goplus/llgo/internal/runtime/c"
+)
+
+// AllocU allocates uninitialized memory.
+func AllocU(size uintptr) unsafe.Pointer {
+	return bdwgc.Malloc(size)
+}
+
+// AllocZ allocates zero-initialized memory.
+func AllocZ(size uintptr) unsafe.Pointer {
+	ret := bdwgc.Malloc(size)
+	return c.Memset(ret, 0, size)
+}
diff --git a/internal/runtime/z_defer.go b/internal/runtime/z_nogc.go
similarity index 65%
rename from internal/runtime/z_defer.go
rename to internal/runtime/z_nogc.go
index fce4230e..1c591387 100644
--- a/internal/runtime/z_defer.go
+++ b/internal/runtime/z_nogc.go
@@ -1,3 +1,6 @@
+//go:build nogc
+// +build nogc
+
 /*
  * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
  *
@@ -16,9 +19,19 @@
 
 package runtime
 
-// Defer presents defer statements in a function.
-type Defer struct {
-	Bits uintptr
-	Link *Defer
-	Rund int // index of RunDefers
+import (
+	"unsafe"
+
+	"github.com/goplus/llgo/internal/runtime/c"
+)
+
+// AllocU allocates uninitialized memory.
+func AllocU(size uintptr) unsafe.Pointer {
+	return c.Malloc(size)
+}
+
+// AllocZ allocates zero-initialized memory.
+func AllocZ(size uintptr) unsafe.Pointer {
+	ret := c.Malloc(size)
+	return c.Memset(ret, 0, size)
 }
diff --git a/internal/runtime/z_c.go b/internal/runtime/z_rt.go
similarity index 77%
rename from internal/runtime/z_c.go
rename to internal/runtime/z_rt.go
index 29eb16ff..4d178efe 100644
--- a/internal/runtime/z_c.go
+++ b/internal/runtime/z_rt.go
@@ -20,20 +20,19 @@ import (
 	"unsafe"
 
 	"github.com/goplus/llgo/internal/abi"
-	"github.com/goplus/llgo/internal/runtime/bdwgc"
 	"github.com/goplus/llgo/internal/runtime/c"
 )
 
-// AllocU allocates uninitialized memory.
-func AllocU(size uintptr) unsafe.Pointer {
-	return bdwgc.Malloc(size)
+// -----------------------------------------------------------------------------
+
+// Defer presents defer statements in a function.
+type Defer struct {
+	Bits uintptr
+	Link *Defer
+	Rund int // index of RunDefers
 }
 
-// AllocZ allocates zero-initialized memory.
-func AllocZ(size uintptr) unsafe.Pointer {
-	ret := bdwgc.Malloc(size)
-	return c.Memset(ret, 0, size)
-}
+// -----------------------------------------------------------------------------
 
 // Zeroinit initializes memory to zero.
 func Zeroinit(p unsafe.Pointer, size uintptr) unsafe.Pointer {
@@ -54,3 +53,5 @@ func stringTracef(fp c.FilePtr, format *c.Char, s String) {
 	cs := c.Alloca(uintptr(s.len) + 1)
 	c.Fprintf(fp, format, CStrCopy(cs, s))
 }
+
+// -----------------------------------------------------------------------------