Is there a way to print build phases and the commands that are executed without modifying the nix file?

I have a very complicated nixpkg that I am trying to install correctly. My file is very similar to this llvm nix file

Are there any flags I can pass to nix-build -A so that I can see the phases as they execute and the commands that they execute.

I would also like to see what is happening without modifying the .nix file.

The dream output of the command would be something like

... more phases ....
 "---- patchPhase---"
    # then the output of the command here
 "---- endPatchPhase---"

.... More phases .... 

 "----- configurePhase---"
 cmake --build .
 "----- endConfigurePhase---"

.... more Phases .....

Put set -x in early might be a workaround.