tcc and its companion program tcc-module do not only take command-line options for themselves, but they can also pass command-line options to programs they invoke.
Each such program invocation is called a ``phase'', and has a one-letter name assigned to it. Options are passed to that specific phase, with the command-line option -Xphase,option
The phases and their names are shown in figure 5.1.
Note the two cpp phases of tcsim and tcc are identified by a upper and lower case ``p'', respectively.
For the external interface, parameters can also be sent to a specific external program (tcc-ext-name) with the phase name xname.