Rsearch On Program Slice Technology And Slice Scheme Design

With the expansion of the software volume,it is becoming increasingly difficult to analyze and solve problems in software.As a decomposition of the technology,program slicing can effectively simplify the problem and plays an important role in many areas of software engineering,such as software metrics,software testing,and program validation.Program slices derived from a large number of branches,such as forward slices,backward slice,static slices,dynamic slices,synchronized dynamic slices,broken slices and so on.The data flow equation algorithm and the graph reachability algorithm are widely used in many areas.This thesis focuses on the modeling methods and calculation steps of data flow equation algorithm and graph reachability algorithm.The data flow equation algorithm is based on the control flow graph of the program,and the iterative calculation of the direct dependency and the indirect dependency is used to calculate the slice on the basis of the control flow graph.The data flow equation algorithm has the characteristics of simple modeling method and complex process of calculation,and it is suitable for the calculation of the process slices.The graph reachability algorithm is based on the dependency graph,and the dependency graphs generate control dependencies and data dependencies in the program into the graphs during the modeling process and use the graph traversal algorithm to compute slices.The graph reachability algorithm has the characteristics of complex modeling process and simple calculation process,but the slice will contain some redundant code.Based on the study of data flow equation algorithm and graph reachability algorithm,two slicing schemes are designed in this thesis,which are block-based program slicing scheme and path-graph-based program slicing scheme.The block-based slice scheme is calculated from the block model of the program,and its slice body is a block in the program rather than an instruction,with the flexibility of the slice criteria and the absence of redundant code in the slice.The path-graph-based slice scheme needs to model the program as a path graph and to complete the calculation by determining the edges in the slice interval.The path-graph-based slice scheme adopts the strategy of indirectly judging the control instruction,which makes the calculation process more simplified;and the slice variable is independent of the instruction,which avoids the generation of redundant code in the slice.In this thesis,the program and the research contents of the program slices are further expanded by designing the block-based slice scheme and the path-graph-based slice scheme.