Static Source Code Checking for User-defined Properties

Only a small fraction of the output generated by typical static analysis tools tends to reveal serious software defects. There are two main causes for this phenomenon. The first is that the typical static analyzer casts its nets too broadly, reporting everything reportable, rather than what is likely to be a true bug. The second cause is that most static analyzers can check the code for only a fixed set of flaws. We describe a simple source code analyzer, UNO, that tries to remedy these problems. The default properties searched for by UNO are restricted to the most common types of error in C programs: use of uninitialized variables, nil-pointer dereferencing, and out-of-bound array indexing. The checking capabilities of UNO can be extended by the user with the definition of applicationdependent properties, which are written as ANSI-C functions.