Research On VM-based Program Spectra Difference Analysis And Fault Localization

With the widely application of computer technology, the scale and complexity of software system rises and the rate of system failure caused by software error continues to increase. It is a meaningful study to make the debugging automated and locate the fault in case of software failure.For the problem of existing software debugging and fault localization, we introduce a virtual machine based program spectra difference analysis and fault localization mechanism and implement it.We analyze the research on software debugging, fault localization and virtual machine, and point out the advantage of virtual machine based fault localization.On the basis of analyzing several common program spectra, the thesis proposed a new program spectrum, the orderly sequence of branch in target code, it could express the characteristics of program run, and unlike the source code level program spectra, it could be obtained without instrumented program. In order to obtain the program spectra through Bochs, we analyze the architecture of the open-source emulator Bochs and the mechanism of CPU module and debugging module in it.This thesis presents the framework of virtual machine based program spectra difference analysis and fault localization. The method uses program spectra to abstractly express a program run. It then selects the correct run that most resembles the faulty run according to a distance criterion, compares the spectra corresponding to these two runs, and produces a report of "suspicious" parts of program.We implement a Bochs based program spectra difference analysis and fault localization system, BPSFLS, and experiment with the Siemens suite of programs with injected bugs. The result shows that the method can effectively locate control flow related fault.