The Jargon File (version 4.4.7, 29 Dec 2003):

hacked up
 adj.

    Sufficiently patched, kluged, and tweaked that the surgical scars are
    beginning to crowd out normal tissue (compare critical mass). Not all
    programs that are hacked become hacked up; if modifications are done with
    some eye to coherence and continued maintainability, the software may
    emerge better for the experience. Contrast hack up.


The Free On-line Dictionary of Computing (30 December 2018):

hacked up

    Sufficiently patched, kluged, and
   tweaked that the surgical scars are beginning to crowd out
   normal tissue (compare critical mass).  Not all programs
   that are hacked become "hacked up"; if modifications are done
   with some eye to coherence and continued maintainability, the
   software may emerge better for the experience.

   Contrast hack up.

   [Jargon File]

   (1996-08-26)