There are six compiler parameters that control the generation of information used by various LispWorks utilities, such as the debugger, and also by various editor commands, such as Show Paths From. By default, these parameters are all t, which allows you to use all the features of these utilities, at the expense of increasing compilation times.
These variables are initially set to t (in the LispWorks file config/a-dot-lispworks.lisp). To speed up compilation times, you should set these variables to nil. The variables can be controlled as a group by using the function toggle-source-debugging.
It is also possible to compile your code with counters or flags such that you can see which parts of your program have actually executed at runtime, as described in Code Coverage.
LispWorks User Guide and Reference Manual - 13 Feb 2015