diff --git a/src/api/hooks.cc b/src/api/hooks.cc
index 82f68cb7fd0add..04fc00c394404b 100644
--- a/src/api/hooks.cc
+++ b/src/api/hooks.cc
@@ -53,7 +53,7 @@ Maybe<bool> EmitProcessBeforeExit(Environment* env) {
       Nothing<bool>() : Just(true);
 }
 
-ExitCode EmitExitInternal(Environment* env) {
+static ExitCode EmitExitInternal(Environment* env) {
   return EmitProcessExitInternal(env).FromMaybe(ExitCode::kGenericUserError);
 }
 
diff --git a/src/env.cc b/src/env.cc
index 5ce5e5dacc1365..43007292cbd177 100644
--- a/src/env.cc
+++ b/src/env.cc
@@ -1521,8 +1521,9 @@ void Environment::Exit(ExitCode exit_code) {
               uv_os_getpid(), thread_id());
     }
 
-    fprintf(
-        stderr, "WARNING: Exited the environment with code %d\n", exit_code);
+    fprintf(stderr,
+            "WARNING: Exited the environment with code %d\n",
+            static_cast<int>(exit_code));
     PrintStackTrace(isolate(),
                     StackTrace::CurrentStackTrace(
                         isolate(), stack_trace_limit(), StackTrace::kDetailed));
diff --git a/src/node.cc b/src/node.cc
index d3820f4c0c338c..d56ae634b1f2fb 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -626,10 +626,10 @@ void ResetStdio() {
 #endif  // __POSIX__
 }
 
-ExitCode ProcessGlobalArgsInternal(std::vector<std::string>* args,
-                                   std::vector<std::string>* exec_args,
-                                   std::vector<std::string>* errors,
-                                   OptionEnvvarSettings settings) {
+static ExitCode ProcessGlobalArgsInternal(std::vector<std::string>* args,
+                                          std::vector<std::string>* exec_args,
+                                          std::vector<std::string>* errors,
+                                          OptionEnvvarSettings settings) {
   // Parse a few arguments which are specific to Node.
   std::vector<std::string> v8_args;
 
@@ -717,7 +717,7 @@ static std::atomic_bool init_called{false};
 
 // TODO(addaleax): Turn this into a wrapper around InitializeOncePerProcess()
 // (with the corresponding additional flags set), then eventually remove this.
-ExitCode InitializeNodeWithArgsInternal(
+static ExitCode InitializeNodeWithArgsInternal(
     std::vector<std::string>* argv,
     std::vector<std::string>* exec_argv,
     std::vector<std::string>* errors,
@@ -839,10 +839,10 @@ int InitializeNodeWithArgs(std::vector<std::string>* argv,
       InitializeNodeWithArgsInternal(argv, exec_argv, errors, flags));
 }
 
-std::unique_ptr<InitializationResultImpl> InitializeOncePerProcessInternal(
-    const std::vector<std::string>& args,
-    ProcessInitializationFlags::Flags flags =
-        ProcessInitializationFlags::kNoFlags) {
+static std::unique_ptr<InitializationResultImpl>
+InitializeOncePerProcessInternal(const std::vector<std::string>& args,
+                                 ProcessInitializationFlags::Flags flags =
+                                     ProcessInitializationFlags::kNoFlags) {
   auto result = std::make_unique<InitializationResultImpl>();
   result->args_ = args;
 
@@ -1165,7 +1165,7 @@ ExitCode LoadSnapshotDataAndRun(const SnapshotData** snapshot_data_ptr,
   return exit_code;
 }
 
-ExitCode StartInternal(int argc, char** argv) {
+static ExitCode StartInternal(int argc, char** argv) {
   CHECK_GT(argc, 0);
 
   // Hack around with the argv pointer. Used for process.title = "blah".