Use the armlink option
generate a symdefs file.
The linker produces a symdefs file during a successful final link stage. It is not produced for partial linking or for unsuccessful final linking.
not exist, the linker creates the file and adds entries for all
the global symbols to that file. If
the linker uses the existing contents of
select the symbols that are output when it rewrites the file. This
means that only the existing symbols in the filename are updated,
and no new symbols (if any) are added at all. If you do not want
this behavior, ensure that any existing symdefs file is deleted
before the link step.