You can navigate to any file dbx recognizes as part of the program, even if a module or file was not compiled with the -g option To navigate to a file:
(dbx) file filename
Using the file command without arguments echoes the file name you are currently navigating.
(dbx) file
dbx displays the file from its first line unless you specify a line number.
(dbx) file filename ; list line-number
For more information, see Setting a Breakpoint at a Line of Source Code.