Is there any recommended way to "rebase" the source tree for definitions in Slime, so that M-.  (slime-edit-definition) will find the definition in the "new" location (for example after a Lisp image has been saved and moved to a new machine, where the source code still exists but is in a different location from where it was during the build)? 

I see code in xref.lisp which looks like it could re-analyze the source code in the new location, but that looks like overkill -- normally this information is already in the Lisp image right? (but probably in an implementation-specific way). 

Anyway all I really need is a way to replace an "old" absolute pathname prefix to the source code with a "new" prefix, reflecting where the source tree is on the current machine. 

Regards,