diff --git a/lib/sources.nix b/lib/sources.nix
index 8d259c0837e..a80e4397d6a 100644
--- a/lib/sources.nix
+++ b/lib/sources.nix
@@ -12,7 +12,10 @@ rec {
       # Filter out Subversion and CVS directories.
       (type == "directory" && (baseName == ".git" || baseName == ".svn" || baseName == "CVS" || baseName == ".hg")) ||
       # Filter out backup files.
-      (lib.hasSuffix "~" baseName)
+      lib.hasSuffix "~" baseName ||
+      # Filter out generates files.
+      lib.hasSuffix ".o" baseName ||
+      lib.hasSuffix ".so" baseName
     );
     in src: builtins.filterSource filter src;