Computer Aided Software Engineering (CASE) tool, unravel.
This tool can assist evaluation of high integrity software by using program slices to extract computations for examination. The tool can currently be used to evaluate software written in ANSI C and is designed such that other languages can be added. Program slicing is a static analysis technique that extracts all statements relevant to the computation of a given variable. Program slicing is useful in program debugging, software maintenance and program understanding. Application of program slicing to evaluation of high integrity software reduces the effort in examining software by allowing a software reviewer to focus attention on one computation at a time. Once a software reviewer has identified a variable for further investigation, the reviewer directs unravel to compute a program slice on the variable. Instead of examining the entire program, only the statements in the slice need to be examined by the reviewer. By speeding up the process of locating relevant code for examination by the reviewer, a larger sample of the software can be inspected with greater confidence that some relevant section of source code has not been missed. The source code for unravel is available and requires a UNIX or POSIX environment, an ANSI C compiler and the MIT X Window System, version 11 release 5 or later.