--- a/python/mozbuild/mozbuild/frontend/emitter.py
+++ b/python/mozbuild/mozbuild/frontend/emitter.py
@@ -136,16 +136,17 @@ ALLOWED_XPCOM_GLUE = {
     ('testcrasher', 'toolkit/crashreporter/test'),
     ('mediaconduit_unittests', 'media/webrtc/signaling/test'),
     ('mediapipeline_unittest', 'media/webrtc/signaling/test'),
     ('sdp_file_parser', 'media/webrtc/signaling/fuzztest'),
     ('signaling_unittests', 'media/webrtc/signaling/test'),
     ('TestMailCookie', 'mailnews/base/test'),
     ('calbasecomps', 'calendar/base/backend/libical/build'),
     ('purplexpcom', 'extensions/purple/purplexpcom/src'),
+    ('ipdlunittest', 'ipc/ipdl/test/cxx/app'),
 }
 
 
 class TreeMetadataEmitter(LoggingMixin):
     """Converts the executed mozbuild files into data structures.
 
     This is a bridge between reader.py and data.py. It takes what was read by
     reader.BuildReader and converts it into the classes defined in the data