questions about AliasAnalysis, llvm3.3 basicaa

Now, I am using llvm-3.3 to do some amazing things, but I am not familiar with AliasAnalysis, so I want to confirm if can I use the interface of the AliasSetTracker to get a single basicblock’s aliasSet(i.e. given a pointer of BasicBlock to the AliasSetTracker then return the alias Set). If it can be implemented by AliasSetTracker , then how? very appreciate your help.