rewriter

noun

1. One who, or that which, rewrites.

   “On the threshold of 1984, Communist rewriters of history have scored a significant victory in their longtime effort to erase inconvenient individuals and events from the chronicle of modern times.”

   “Part of why both books dragged on so long is that Mr. Talese, who once worked for The New York Times, is a perfectionist, an obsessive tinkerer and rewriter, and also a famously meticulous reporter and researcher who spurns devices like composite characters and faked identities.”

2. Part of a compiler that makes a second pass to fix the generated object code by implementing postconditions, patching in calls or pointers to point to the correct locations, etc.