The Chicago Public Library's Harold Washington Library Center has the Municipal Reference Collection - they keep all old, new and revised municipal codes on file!

Municipal Code of Chicago
(a.k.a. Laws and ordinances governing the city of Chicago, revised Chicago code)
Edition hosted by the City Clerk's Office
The recent municipal codes in Govinfo department had been updated irregularly until circa 1998 but we no longer receive updated codes.

Chicago Municipal Code: How to Find and Research Historical Codes provides a comprehensive review of what codes were published (building codes, zoning ordinances, special codes), what they were called, and where you can find them.  Some of these materials are available online, and most of the print editions are available at the Chicago Public Library's Municipal Reference Collection at the downtown Harold Washington Library.

Chicago Municipal Code ; Zoning Ordinance ; Building Code
Recent, updated codes & ordinances by American Legal Publishing provided through the City of Chicago

City Clerk of Chicago - historical records available as described on the Chicago Collections Consortium website