History-based call stack construction

• US 20080209406A1
• Filed: 02/27/2007
• Published: 08/28/2008
• Est. Priority Date: 02/27/2007
• Status: Abandoned Application

• Current Assignee: RPX Corporation
• Original Assignee: Novell Incorporated (Open Text Corporation)
• Inventors: O'Callahan, Robert Weeks
• Application Number:
  US11/711,387
• Publication Number:
  US 20080209406A1
• Time in Patent Office: Days
• US Class Current: 717/131
• CPC Class Codes: G06F 11/3476 Data logging G06F11/14, G06F11/2205 take precedence
• CPC Class Codes: G06F 11/3636 by tracing the execution of the program
• CPC Class Codes: G06F 2201/865 Monitoring of software

Abstract

In a computing system environment, methods and apparatus relate to constructing a call stack for a software program based upon a comprehensive recording of an execution history of the software program. Upon defining procedure calls and returns in the execution history, a call stack is constructed for the procedure calls having no corresponding returns, but without reading or otherwise examining allocated stack memory or registers, such as return addresses. In this manner, an accurate call stack can be constructed despite stack memory or registers being erased or corrupted or despite various compiler optimizations eliminating convenience or otherwise complicating the construction. Nuances for defining procedure calls and returns as well as stack pointer values for same are also contemplated. Still other embodiments relate to stand-alone computer program products (on computer-readable media or as a download, or other) or those working in conjunction with other programs.

Claims

1. In a computing environment, a method of constructing a call stack for a software program, the call stack having allocated memory or registers in the computing environment, comprising:

obtaining a comprehensive recording of an execution history of the program;

determining which procedure calls have no corresponding returns, the returns having a corresponding return address in either the allocated memory or registers; and

for display to a user in the computing environment, constructing a list of the determined procedure calls having no corresponding returns without reading the return address in the allocated memory or registers.

2. The method of claim 1, further including defining the procedure calls as any of a plurality of call instructions in the execution history not calling a target of an immediate next instruction.

3. The method of claim 1, further including defining the procedure calls as any of a plurality of control transfers in the execution history to an instruction having a procedure label.

4. The method of claim 1, further including defining the returns as any of a plurality of returns before a time T2 whereby a stack pointer value at a time T is greater than a stack pointer value at a time T1, whereby T1<

T≦

T2.

5. The method of claim 1, further including iterating a backward progression to determine a timestamp of a most recent of the procedure calls have no corresponding returns.

6. The method of claim 1, further including establishing a candidate set of stack pointer values earlier or concurrent to a time corresponding to the constructing the list of the determined procedure calls having no corresponding returns.

7. The method of claim 6, further including filtering out stack pointer values having related returns from the candidate set of stack pointer values.

8. The method of claim 7, wherein the filtering out further includes determining a last time less than the time such that the last time immediately follows one of the procedure calls and a stack pointer value for the last time is greater than a stack pointer value for the time.

9. A computer program product having computer-executable instructions for performing the determining and constructing steps recited in claim 1.

15. The method of claim 1, further including establishing a candidate set of stack pointer values earlier or concurrent to a time corresponding to the constructing the list of the determined procedure calls having no corresponding returns.

10. In a computing environment, a method of constructing a call stack for a software program, comprising:

allocating memory or registers in the computing environment to the call stack;

recording an execution history of the program;

determining which procedure calls of the execution history have no corresponding returns, the returns having a corresponding return address in either the allocated memory or registers;

constructing a list of the determined procedure calls having no corresponding returns without reading the return address in the allocated memory or registers; and

displaying the constructed list as a call stack to a user in the computing environment.

11. The method of claim 10, further including defining the procedure calls as any of a plurality of call instructions in the execution history not calling a target of an immediate next instruction.

12. The method of claim 10, further including defining the procedure calls as any of a plurality of control transfers in the execution history to an instruction having a procedure label.

13. The method of claim 10, further including defining the returns as any of a plurality of returns before a time T2 whereby a stack pointer value at a time T is greater than a stack pointer value at a time T1, whereby T1<

T≦

T2.

14. The method of claim 10, further including iterating a backward progression to determine a timestamp of a most recent of the procedure calls have no corresponding returns.

16. A computer program product having computer-executable instructions for installation on a computing device for constructing a call stack for a software program on or in communication with the computing device, the call stack having allocated memory or registers in the computing environment, comprising:

a first component functional to understand a comprehensive recording of an execution history of the program;

a second component to determine which procedure calls of the execution history have no corresponding returns, the returns having a corresponding return address in either the allocated memory or registers;

a third component to construct a stacked list of the determined procedure calls having no corresponding returns without reading any of the return addresses in the allocated memory or registers; and

a fourth component functional to cause display to a user of the stacked list on a monitor of the computing device.

17. The computer program product of claim 16, further including a fifth component setting the procedure calls as any of a plurality of call instructions in the execution history not calling a target of an immediate next instruction.

18. The computer program product of claim 16, further including a fifth component setting the procedure calls as any of a plurality of control transfers in the execution history to an instruction having a procedure label.

19. The computer program product of claim 16, further including a fifth component setting the returns as any of a plurality of returns before a time T2 whereby a stack pointer value at a time T is greater than a stack pointer value at a time T1, whereby T1<

T≦

T2.

20. The computer program product of claim 16, further including a fifth component iterating a backward progression to determine a timestamp of a most recent of the procedure calls have no corresponding returns.

21. The computer program product of claim 16, further including a fifth component establishing a candidate set of stack pointer values earlier or concurrent to a time corresponding to the constructing the list of the determined procedure calls having no corresponding returns.

22. The computer program product of claim 21, further including a fifth component filtering out stack pointer values having related returns from the candidate set of stack pointer values.

23. The computer program product of claim 22, further including a fifth component determining a last time less than the time such that the last time immediately follows one of the procedure calls and a stack pointer value for the last time is greater than a stack pointer value for the time.