A Method Of Software Forewarning Based On Control Flow Information And Program Invariants

Computer software has been widely used in all aspects of the national economy. But large-scale development of software also increases the security risks of software. All of software inevitably contain errors. So improving software quality has been an increasingly popular topic.This thesis proposes a software fault dynamic forewarning method based upon previous works. First of all, there are the analysis and comparison of several current popular methods. Then, a method of software forewarning based on control-flow information and program invariants comes out. The method analyzes software source code with control flow information and invariants rules. A set of static information extracted from the source code is input to the warning method, and describe and store the information in the form of XML files, then inserted into the source code of the program for processing. In the method based on control-flow information, control flow information of the input model is read, and control-flow graphs is generated and the source code is divided in basic blocks, then every block is recorded with a sequence number. The code snippets of detect jumping information and the sequence number is inserted into the source code, then monitoring program jumping with forewarning, when illegal jump occurred in the program, the system will point out the warning message immediately. And in the method based on program invariants, automatically generating pre-invariants or post-invariants by a third-party tool, coupled with manually add the loop invariants, and class invariants, then storing the information of the invariants in the form of XML files, which includes the program statements in invariants and the position that invariants will be inserted in source code. Then invariants will be inserted into source code in the appropriate location in the form of annotation. Then annotation forms of invariants information will be translated into an assertion which during program execution can be identified. The code will have the function of forewarning. In the process of running time, we can verify the correctness of the program invariants to ensure that the program runs correctly. In this paper, the method of software forewarning based on control-flow information and program invariants, expands the wrong type of forewarning, improves fault dynamic detection rate and makes a more comprehensive fault forewarning method.With practical examples, the thesis proves that the fault forewarning method has a good performance, and shows results to users and presents the availability of the method.