Janice C Shepherd

US Patent:

6442751, Aug 27, 2002

Filed:

Dec 14, 1998

Appl. No.:

09/211388

Inventors:

Anthony Cocchi - Riverside CT
Janice Cynthia Shepherd - Ossining NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 945

US Classification:

717133, 717132, 717154, 717155, 717156, 717157, 707205, 707206

Abstract:

A method is provided for tracking the type of at least one local variable after calling a subroutine. The exemplary method associates each one of a plurality of branch instructions calling the subroutine with a first information, which indicates the type of value stored in the local variable when each one of the plurality of branch instructions is executed. The exemplary method associates at least one execution point-of-interest within the subroutine with a second information. The execution point-of-interest is any point within the subroutine where it may be necessary to ascertain the type of each local variable. The second information is a data structure indicating a change in type made to the local variable after entering the subroutine and before the execution point-of-interest. The exemplary method associates the execution point-of-interest with a return address for the subroutine. This return address enables the method to identify the point in the calling program from which the current subroutine was called.