System for determining a total error description of at least one part of a computer program

• US 7,047,523 B1
• Filed: 04/03/2000
• Issued: 05/16/2006
• Est. Priority Date: 06/02/1999
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Liggesmeyer, Peter
• Primary Examiner(s): NGUYEN BA, HOANG VU A
• Application Number:
  US09/980,489
• Time in Patent Office: 2,234 Days
• Field of Search: 717131-133, 717154-156, 714/26, 714/57, 714/38, 714/48, 714/79, 714/799
• US Class Current: 717/132
• CPC Class Codes: G06F 11/008 Reliability or availability analysis
• CPC Class Codes: G06F 11/0796 Safety measures, i.e. ensuring safe condition in the event of error, e.g. for controlling element
• CPC Class Codes: G06F 11/3604 Software analysis for verifying properties of programs byte-code verification G06F9/44589

Abstract

A section of a computer program is used to ascertain a control flow description and a data flow description, and program elements are selected from the section of the computer program. For each selected program element, a stored fault description associated with a respective reference element is used to ascertain an element fault description which describes possible faults in the respective program element. The element fault descriptions are used to ascertain the overall fault description, taking into account the control flow description and the data flow description.

Claims

1. A method for using a computer to ascertain an overall fault description for at least one section of a computer program, comprising:

storing fault descriptions associated with reference elements to describe possible faults in the reference elements, respectively;

storing a section of the computer program;

ascertaining a control flow description for the section of the computer program, to describe a flow of control information in the section of the computer program;

ascertaining a data flow description for the section of the computer program, to describe a flow of data in the section of the computer program;

combining the control and data flow descriptions into a joint flow description for the section of the computer program;

selecting program elements from the section of the computer program;

matching each selected program element with a corresponding reference element to obtain a fault description associated with the corresponding reference element and thereby describe possible faults in the selected program element;

ascertaining the overall fault description as an overall fault tree using the fault descriptions of the program elements from the computer program, with a structure of the overall fault description taking into account a structure of the joint flow description; and

altering the overall fault tree in terms of prescribable boundary conditions.

2. The method as claimed in claims 1, wherein the control flow description is a control flow graph.

3. The method as claimed in claims 1, wherein the data flow description is a data flow graph.

4. The method as claimed in claim 1,

wherein each of the fault descriptions associated with the reference elements is a fault tree, and

wherein the overall fault description is ascertained as the overall fault tree based on fault trees associated with the corresponding reference element for each selected program element.

5. The method as claimed in claims 1, further comprising performing fault analysis in the section of the computer program using the overall fault description.

6. The method as claimed in claim 1, wherein said altering comprises adding a complementary fault tree.

7. A system for ascertaining an overall fault description for at least one section of a computer program, comprising:

a storage unit to store the at least one section of the computer program and fault descriptions for reference elements, each fault description describing possible faults in one of the reference elements; and

a processor, coupled to said storage unit,

to ascertain control and data flow descriptions for the at least one section of the computer program, the control flow description describing a flow of control information in the at least one section of the computer program and the data flow description describing a flow of data in the at least one section of the computer program,

to combine the control and data flow descriptions into a joint flow description for the at least one section of the computer program,

to select program elements from the at least one section of the computer program,

to match each selected program element with a corresponding reference element and obtain a fault description associated with the corresponding reference element and thereby describe possible faults in the selected program element; and

to ascertain the overall fault description as an overall fault tree using the fault descriptions of the program elements from the computer program, with a structure of the overall fault description taking into account a structure of the joint flow description; and

to alter the overall fault tree in terms of prescribable boundary conditions.

8. The method as claimed in claim 7, wherein said processor ascertains the control flow description as a control flow graph.

9. The system as claimed in claim 7, wherein said processor ascertains the data flow description as a data flow graph.

10. The system as claimed in claim 7,

wherein said storage unit stores each fault description as a fault tree, and

wherein said processor ascertains each element fault description as an element fault tree and the overall fault description as an overall fault tree.

11. The system as claimed in claim 7, wherein said processor further performs fault analysis in the at least one section of the computer program using the overall fault description.

12. The system as claimed in claim 7, wherein said processor alters the overall fault tree by adding a complementary fault tree.

13. A computer-readable storage medium storing at least one program to control a computer to perform a method for ascertaining an overall fault description for at least one section of a computer program, said method comprising:

storing a section of the computer program;

ascertaining a control flow description for the section of the computer program, to describe a flow of control information in the section of the computer program;

ascertaining a data flow description for the section of the computer program, to describe a flow of data in the section of the computer program;

combining the control and data flow descriptions into a joint flow description for the section of the computer program;

selecting program elements from the section of the computer program;

storing a fault description for each reference element to describe possible faults in the reference element;

matching each selected program element with a corresponding reference element to obtain a fault description associated with the corresponding reference element and thereby describe possible faults in the selected program element;

ascertaining the overall fault description as an overall fault tree using the fault descriptions of the program elements from the computer program, with a structure of the overall fault description taking into account a structure of the joint flow description; and

altering the overall fault tree in terms of Prescribable boundary conditions.

14. A computer-readable storage medium as claimed in claim 13, wherein said computer alters the overall fault tree by adding a complementary fault tree.