Existing tree functionality?

[Michael Tegtmeyer]

> pass_init_datastructures is still necessary.

That was the problem-thanks.

New question (or still the original rather), is there existing 
functionality to obtain the variables used in a function with external 
visibility for that function-or in other words-any variable not local to 
that function? is_global_vars() works for globals but misses:

struct foo {
 	int i;
 	void bar() {i=10;}
};

In bar, 'i' is not global but is not passed in via arguments either. 
referenced_vars contains the 'this' ptr. Is there anything existing that 
will obtain 'i' as an external variable w.r.t. bar?

Thanks again,
Mike