byte-compile-file is an interactive autoloaded compiled Lisp function in `bytecomp.el'.

(byte-compile-file FILENAME &optional LOAD)

Compile a file of Lisp code named FILENAME into a file of byte code.
The output file's name is generated by passing FILENAME to the
function `byte-compile-dest-file' (which see).
With prefix arg (noninteractively: 2nd arg), LOAD the file after compiling.
The value is non-nil if there were no errors, nil if errors.