diff --git a/compiler/erg_common/config.rs b/compiler/erg_common/config.rs
index 53a25ca2..92ed3e2e 100644
--- a/compiler/erg_common/config.rs
+++ b/compiler/erg_common/config.rs
@@ -38,7 +38,7 @@ impl Input {
 
     pub fn enclosed_name(&self) -> &str {
         match self {
-            Self::File(filename) => filename.to_str().unwrap_or("???"),
+            Self::File(filename) => filename.to_str().unwrap_or("_"),
             Self::REPL | Self::Pipe(_) => "<stdin>",
             Self::Str(_) => "<string>",
             Self::Dummy => "<dummy>",
@@ -47,7 +47,7 @@ impl Input {
 
     pub fn full_path(&self) -> &str {
         match self {
-            Self::File(filename) => filename.to_str().unwrap_or("???"),
+            Self::File(filename) => filename.to_str().unwrap_or("_"),
             Self::REPL | Self::Pipe(_) => "stdin",
             Self::Str(_) => "string",
             Self::Dummy => "dummy",
@@ -56,10 +56,7 @@ impl Input {
 
     pub fn filename(&self) -> &str {
         match self {
-            Self::File(filename) => filename
-                .file_name()
-                .and_then(|f| f.to_str())
-                .unwrap_or("???"),
+            Self::File(filename) => filename.file_name().and_then(|f| f.to_str()).unwrap_or("_"),
             Self::REPL | Self::Pipe(_) => "stdin",
             Self::Str(_) => "string",
             Self::Dummy => "dummy",
@@ -266,6 +263,32 @@ impl ErgConfig {
         }
     }
 
+    pub fn dump_filename(&self) -> String {
+        if let Some(output) = &self.output_dir {
+            format!("{output}/{}", self.input.filename())
+        } else {
+            self.input.filename().to_string()
+        }
+    }
+
+    pub fn dump_pyc_path(&self) -> String {
+        let dump_path = self.dump_path();
+        if dump_path.ends_with(".er") {
+            dump_path.replace(".er", ".pyc")
+        } else {
+            dump_path + ".pyc"
+        }
+    }
+
+    pub fn dump_pyc_filename(&self) -> String {
+        let dump_filename = self.dump_filename();
+        if dump_filename.ends_with(".er") {
+            dump_filename.replace(".er", ".pyc")
+        } else {
+            dump_filename + ".pyc"
+        }
+    }
+
     pub fn inherit(&self, path: PathBuf) -> Self {
         Self {
             module: Box::leak(path.to_str().unwrap().to_string().into_boxed_str()),
diff --git a/compiler/erg_compiler/compile.rs b/compiler/erg_compiler/compile.rs
index daf89106..1dd874bb 100644
--- a/compiler/erg_compiler/compile.rs
+++ b/compiler/erg_compiler/compile.rs
@@ -147,7 +147,7 @@ impl Runnable for Compiler {
     }
 
     fn exec(&mut self) -> Result<i32, Self::Errs> {
-        let path = self.cfg.dump_path().replace(".er", ".pyc");
+        let path = self.cfg.dump_pyc_path();
         let warns = self
             .compile_and_dump_as_pyc(path, self.input().read(), "exec")
             .map_err(|eart| {
diff --git a/src/dummy.rs b/src/dummy.rs
index 0f0d1d4a..3ec485f9 100644
--- a/src/dummy.rs
+++ b/src/dummy.rs
@@ -121,14 +121,7 @@ impl Runnable for DummyVM {
 
     fn exec(&mut self) -> Result<i32, Self::Errs> {
         // Parallel execution is not possible without dumping with a unique file name.
-        let filename = self
-            .cfg()
-            .input
-            .full_path()
-            .split('/')
-            .last()
-            .unwrap()
-            .replace(".er", ".pyc");
+        let filename = self.cfg().dump_pyc_filename();
         let warns = self
             .compiler
             .compile_and_dump_as_pyc(&filename, self.input().read(), "exec")