diff --git a/builtin.c b/builtin.c
index bcc5dc61a4..d936d1ceb6 100644
--- a/builtin.c
+++ b/builtin.c
@@ -18,7 +18,7 @@ builtin_lookup(const char *feature, size_t *psize)
 }
 
 void
-rb_load_with_builtin_functions(const char *feature_name, const char *fname, const struct rb_builtin_function *table)
+rb_load_with_builtin_functions(const char *feature_name, const struct rb_builtin_function *table)
 {
     // search binary
     size_t size;
diff --git a/builtin.h b/builtin.h
index ef6ff82236..ee99e21dcc 100644
--- a/builtin.h
+++ b/builtin.h
@@ -12,7 +12,7 @@ struct rb_builtin_function {
 
 #define RB_BUILTIN_FUNCTION(_i, _name, _arity) { .name = #_name, .func_ptr = (void *)_name, .argc = _arity, .index = _i }
 
-void rb_load_with_builtin_functions(const char *feature_name, const char *fname, const struct rb_builtin_function *table);
+void rb_load_with_builtin_functions(const char *feature_name, const struct rb_builtin_function *table);
 
 #ifndef VM_CORE_H_EC_DEFINED
 typedef struct rb_execution_context_struct rb_execution_context_t;
diff --git a/mini_builtin.c b/mini_builtin.c
index 290a4b335e..8bb262c45e 100644
--- a/mini_builtin.c
+++ b/mini_builtin.c
@@ -10,7 +10,7 @@ static struct st_table *loaded_builtin_table;
 rb_ast_t *rb_builtin_ast(const char *feature_name, VALUE *name_str);
 
 void
-rb_load_with_builtin_functions(const char *feature_name, const char *fname, const struct rb_builtin_function *table)
+rb_load_with_builtin_functions(const char *feature_name, const struct rb_builtin_function *table)
 {
     VALUE name_str = 0;
     rb_ast_t *ast = rb_builtin_ast(feature_name, &name_str);
diff --git a/tool/mk_builtin_loader.rb b/tool/mk_builtin_loader.rb
index 87b5e2ab76..4f140a6f6b 100644
--- a/tool/mk_builtin_loader.rb
+++ b/tool/mk_builtin_loader.rb
@@ -67,10 +67,9 @@ def mk_builtin_header file
     f.puts "COMPILER_WARNING_POP"
 
 
-    path = File.expand_path(file)
     f.puts
     f.puts "  // load"
-    f.puts "  rb_load_with_builtin_functions(\"#{base}\", \"#{file}\", #{table});"
+    f.puts "  rb_load_with_builtin_functions(#{base.dump}, #{table});"
 
     f.puts "}"
   }
@@ -78,6 +77,5 @@ end
 
 ARGV.each{|file|
   # feature.rb => load_feature.inc
-  path = File.expand_path(file)
-  mk_builtin_header path
+  mk_builtin_header file
 }