Osaka University

When we debug and maintain large software, it is very important to localize the scope of our concern to small program portions. Program slicing is one of promising techniques for identifying portions of interest. There are many research results on the program slicing method. A static slice, which is a collection of program statements possibly aecting a particular variable's value, limits the scope, but the resulting collections are often still large. A dynamic slice, which is a collection of executed pro-gram statements aecting a particular variable's value, generally reduces the scope considerably, but its com-putation is expensive since the execution trace of the program must be recorded. In this paper, we propose a new slicing technique named call-mark slicing that combines static analysis of a program's structure with lightweight dynamic analysis. The data dependences and control dependences among the program statements are statically analyzed before-hand, and procedure/function invocations (calls) are recorded (marked) during execution. From this infor-mation, the dynamic dependences of the variables are explored. This call-mark slicing mechanism has been imple-mented, and the eectiveness of the method has been investigated