Contruction of call multigraphs revisited

This paper presents an algorithm for constructing call multigraphs for procedural language programs. The call graph construction (CGC) problem is analogous to the problem of performing control flow analysis (CFA) of Scheme [Shi88, Shi91b]. As shown later, this problem is also analogous to the problem of determining types (TD) at specific program points for object-oriented languages [PS91, PR93, Suz81]. Our CGC algorithm may be easily adapted to perform CFA and TD. The algorithm is significant since the CGC, CFA, and TD problems are of fundamental importance for efficient compilation of programs in procedural, functional, and object-oriented languages, respectively. Pande & Ryder [PR93] have shown that the TD problem is NP-hard in the presence of single-level pointers. We show that the CGC problem is analogous to the TD problem. The CGC problem too is, therefore, intractable. Any polynomial algorithm for it can only give approximate results. The algorithm presented makes the following contributions: