Tree shlysis(Tree t, barrier foo)
Do a sharing analysis : annotates all the subtrees of t with there occurences.
A CTree = (Node x [CTree]) is a Node associated with a list of subtrees called branches.
bool(* barrier)(const Tree &t)
Tree shprkey(Tree t)
Create a specific property key for the sharing count of subtrees of t.
int shcount(Tree key, Tree t)
Return the value of sharing count or 0.