A Sharing Analysis for SAFE

We present a sharing analysis for the functional language Safe. This is a first-order eager language with facilities for programmer-controlled destruction and copying of data structures. It provides also regions, i.e. disjoint parts of the heap where the programmer may allocate data structures. The analysis gives upper approximations to the sets of variables respectively sharing a recursive substructure, or any substructure, of a given variable. Its results will be used to guarantee that destruction facilities and region management are done in a safe way. In order to have a modular and efficient analysis, we provide signatures for functions, which summarize their sharing behaviour. The paper ends up describing the implementation of the analysis and some examples.