diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index aef7fa6..5fb00d5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -109,6 +109,7 @@ jobs:
           ./build/qjs examples/test_fib.js
           ./build/qjs examples/test_point.js
           ./build/qjs tests/test_bjson.js
+          ./build/function_source
   linux-shared:
     runs-on: ubuntu-latest
     steps:
@@ -213,6 +214,7 @@ jobs:
           ./build/qjs examples/test_fib.js
           ./build/qjs examples/test_point.js
           ./build/qjs tests/test_bjson.js
+          ./build/function_source
   macos-shared:
     runs-on: macos-latest
     steps:
@@ -261,6 +263,7 @@ jobs:
         run: |
           cmake -B build -DCMAKE_BUILD_TYPE=${{matrix.buildType}} -G "Visual Studio 17 2022" -T ClangCL
           cmake --build build --target qjs_exe
+          cmake --build build --target function_source
       - name: stats
         run: |
           cmd /r build\Debug\qjs.exe -qd
@@ -274,6 +277,7 @@ jobs:
           cmd /r build\Debug\qjs.exe tests\test_std.js
           cmd /r build\Debug\qjs.exe tests\test_worker.js
           cmd /r build\Debug\qjs.exe tests\test_queue_microtask.js
+          cmd /r build\Debug\function_source.exe
 
   windows-mingw:
     runs-on: windows-latest
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7e4cbc4..2d7eaf5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -236,6 +236,21 @@ add_executable(unicode_gen EXCLUDE_FROM_ALL
 )
 target_compile_definitions(unicode_gen PRIVATE ${qjs_defines})
 
+add_custom_command(
+    OUTPUT function_source.c
+    COMMAND qjsc -e -o function_source.c ${CMAKE_CURRENT_SOURCE_DIR}/tests/function_source.js
+    DEPENDS qjsc ${CMAKE_CURRENT_SOURCE_DIR}/tests/function_source.js
+    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+    COMMENT "Compile function_source.js to a C file with bytecode embedded"
+    SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/tests/function_source.js
+)
+add_executable(function_source
+    ${CMAKE_CURRENT_BINARY_DIR}/function_source.c
+    quickjs-libc.c
+)
+target_include_directories(function_source PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
+target_compile_definitions(function_source PRIVATE ${qjs_defines})
+target_link_libraries(function_source ${qjs_libs})
 
 # Examples
 #
@@ -246,7 +261,7 @@ if(BUILD_EXAMPLES AND NOT WIN32)
         COMMAND qjsc -e -o hello.c ${CMAKE_CURRENT_SOURCE_DIR}/examples/hello.js
         DEPENDS qjsc
         WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
-        COMMENT "Compile hello.js to a C file with bytecode embeddee"
+        COMMENT "Compile hello.js to a C file with bytecode embedded"
         SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/examples/hello.js
     )
     add_executable(hello
@@ -262,7 +277,7 @@ if(BUILD_EXAMPLES AND NOT WIN32)
         COMMAND qjsc -e -o hello_module.c -m ${CMAKE_CURRENT_SOURCE_DIR}/examples/hello_module.js
         DEPENDS qjsc
         WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
-        COMMENT "Compile hello_module.js to a C file with bytecode embeddee"
+        COMMENT "Compile hello_module.js to a C file with bytecode embedded"
         SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/examples/hello_module.js
     )
     add_executable(hello_module
diff --git a/cutils.c b/cutils.c
index 9b1c871..088e75e 100644
--- a/cutils.c
+++ b/cutils.c
@@ -129,7 +129,7 @@ int dbuf_realloc(DynBuf *s, size_t new_size)
     return 0;
 }
 
-int dbuf_write(DynBuf *s, size_t offset, const uint8_t *data, size_t len)
+int dbuf_write(DynBuf *s, size_t offset, const void *data, size_t len)
 {
     size_t end;
     end = offset + len;
@@ -141,7 +141,7 @@ int dbuf_write(DynBuf *s, size_t offset, const uint8_t *data, size_t len)
     return 0;
 }
 
-int dbuf_put(DynBuf *s, const uint8_t *data, size_t len)
+int dbuf_put(DynBuf *s, const void *data, size_t len)
 {
     if (unlikely((s->size + len) > s->allocated_size)) {
         if (dbuf_realloc(s, s->size + len))
diff --git a/cutils.h b/cutils.h
index 5cf1b8a..23b3da4 100644
--- a/cutils.h
+++ b/cutils.h
@@ -277,8 +277,8 @@ typedef struct DynBuf {
 void dbuf_init(DynBuf *s);
 void dbuf_init2(DynBuf *s, void *opaque, DynBufReallocFunc *realloc_func);
 int dbuf_realloc(DynBuf *s, size_t new_size);
-int dbuf_write(DynBuf *s, size_t offset, const uint8_t *data, size_t len);
-int dbuf_put(DynBuf *s, const uint8_t *data, size_t len);
+int dbuf_write(DynBuf *s, size_t offset, const void *data, size_t len);
+int dbuf_put(DynBuf *s, const void *data, size_t len);
 int dbuf_put_self(DynBuf *s, size_t offset, size_t len);
 int dbuf_putc(DynBuf *s, uint8_t c);
 int dbuf_putstr(DynBuf *s, const char *str);
diff --git a/qjsc.c b/qjsc.c
index cb584a3..98a4d2b 100644
--- a/qjsc.c
+++ b/qjsc.c
@@ -305,6 +305,7 @@ static const char main_c_template1[] =
 static const char main_c_template2[] =
     "  js_std_loop(ctx);\n"
     "  JS_FreeContext(ctx);\n"
+    "  js_std_free_handlers(rt);\n"
     "  JS_FreeRuntime(rt);\n"
     "  return 0;\n"
     "}\n";
diff --git a/quickjs.c b/quickjs.c
index 88f5d8e..c56b963 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -32018,7 +32018,7 @@ typedef enum BCTagEnum {
     BC_TAG_OBJECT_REFERENCE,
 } BCTagEnum;
 
-#define BC_VERSION 7
+#define BC_VERSION 8
 
 typedef struct BCWriterState {
     JSContext *ctx;
@@ -32440,6 +32440,8 @@ static int JS_WriteFunctionTag(BCWriterState *s, JSValue obj)
     bc_put_leb128(s, b->col_num);
     bc_put_leb128(s, b->pc2line_len);
     dbuf_put(&s->dbuf, b->pc2line_buf, b->pc2line_len);
+    bc_put_leb128(s, b->source_len);
+    dbuf_put(&s->dbuf, b->source, b->source_len);
 
     /* compatibility */
     dbuf_putc(&s->dbuf, 255);
@@ -33017,7 +33019,7 @@ static int bc_get_leb128_u16(BCReaderState *s, uint16_t *pval)
     return 0;
 }
 
-static int bc_get_buf(BCReaderState *s, uint8_t *buf, uint32_t buf_len)
+static int bc_get_buf(BCReaderState *s, void *buf, uint32_t buf_len)
 {
     if (buf_len != 0) {
         if (unlikely(!buf || s->buf_end - s->ptr < buf_len))
@@ -33413,6 +33415,15 @@ static JSValue JS_ReadFunctionTag(BCReaderState *s)
         if (bc_get_buf(s, b->pc2line_buf, b->pc2line_len))
             goto fail;
     }
+    if (bc_get_leb128_int(s, &b->source_len))
+        goto fail;
+    if (b->source_len) {
+        b->source = js_mallocz(ctx, b->source_len);
+        if (!b->source)
+            goto fail;
+        if (bc_get_buf(s, b->source, b->source_len))
+            goto fail;
+    }
     if (s->buf_end - s->ptr > 3 && s->ptr[0] == 255 &&
         s->ptr[1] == 73 && s->ptr[2] == 67) {
         s->ptr += 3;
diff --git a/tests/function_source.js b/tests/function_source.js
new file mode 100644
index 0000000..640420a
--- /dev/null
+++ b/tests/function_source.js
@@ -0,0 +1,14 @@
+"use strict"
+const expect = "function f() { return 42 }"
+function f() { return 42 }
+
+{
+    const actual = f.toString()
+    if (actual !== expect) throw Error(actual)
+}
+
+{
+    const f = eval(expect + "f")
+    const actual = f.toString()
+    if (actual !== expect) throw Error(actual)
+}