In example.cl you should write a correct Cool program which
	tests as many aspects of the code generator as possible. It
	should pass your code generator, and running spim on the
	generated output should run the program correctly.

	cgen.cc is the skeleton file for the code generator. 
	The skeleton provides three components of the
	code generator:

		- functions to build the inheritance graph; (we supply
		  this in case you didn't get this working for PA4)

		- functions to emit global data and constants;
		 
		- functions to emit spim instructions; (we supply
		  these last two to save you some tedious coding)

	You should work to understand this code, and it will help you
        write the rest of the code generator.

	cgen.h is the header file for the code generator. Feel free to
	add anything you need.

	cgen_supp.cc is general support code for the code generator.
	You can add functions as you see fit, but do not modify the 3
	functions:

		o byte_mode
		o ascii_mode
		o emit_string_constant

	emit.h defines a bunch of macros which should come in handy
	when you actually want to emit code. Feel free to change
	anything here to suit your needs.
        For this assignment, -c
        (code generator debug) may be useful as it sets a global
        variable cgen_debug to true (1).  If you want your code
        generator to print debug information when the option is set,
        write your debug code in the following format:

	      if (cgen_debug)
	      {
		...
	      }