https://gcc.gnu.org/onlinedocs/gcc-4.4.4/gnat_ugn_unw/Project-Files-for-gnatxref-and-gnatfind.html
Project Files for gnatxref and gnatfind - GNAT User's Guide
project filesgnatuserguide
https://gcc.gnu.org/onlinedocs/gcc-4.4.4/gnat_ugn_unw/The-Cross_002dReferencing-Tools-gnatxref-and-gnatfind.html
The Cross-Referencing Tools gnatxref and gnatfind - GNAT User's Guide
the crossreferencing tools