Interprocedural Dataflow Analysis - Scalability issues

[Virender Kashyap]

Hi,
    I am working on interprocedural data flow analysis(IPDFA) and need some 
feedback on scalability issues in IPDFA. Firstly since one file is 
compiled at a time, we can do IPDFA only within a file. But that would 
prevent us from doing analysis for funcitons which are called in file 
A , but are defined in some other file B. So even if we do any analysis it 
would give limited advantage. Morever even if we are able to store 
information of  large number of functions, it would cost heavily in 
memory, and threfore non scalable.
         So, to what extent can IPDFA be advantageous ?  Or, are there 
solutions to above problems ?

Regards,

Virender.