Etags

The helm-etags-select command, bound to <helm-prefix> e by default, can be used to navigate TAGS files built with etags. To jump to the definition of the symbol at point, invoke the command with a universal prefix (C-u <helm-prefix> e).

If the project is big, It take some time to load the TAGS file. Once loading is done, however, the next search will be very fast.

Create TAGS file

To use etags in Emacs, you must first create a TAGS file for your project with the etags shell command. If your directory contains sub-directories, use something like the following:

find . -iregex .*\.el$ | xargs etags

Otherwise, using the following is enough:

etags *.el

For more information, see the Emacs manual section on Tags tables or the etags man page.

Refresh TAGS file

If you modify the TAGS file, call C-u C-u <helm-prefix> e to refresh tag cache.