Abstract: A method of back-tracing execution of a computer program, where the computer program comprises a plurality of blocks, comprises instrumenting an original version of the program by adding instrumentation code to some or all of the blocks to form an instrumented program. Instrumentation can be added at the binary or source level, or at link time. The instrumentation code records execution sequence information upon execution of the corresponding instrumented block to create a trace record of the executed program. The execution sequence information for each block comprises a block identifier which identifies the corresponding block. A detailed back-trace is generated, after the program has executed, by replacing each recorded block identifier with program counters associated with each instruction in the corresponding block. The application may comprise several programs or subprograms, in which case separate regions of memory can be maintained.

Abstract: A method of generating a program control flow definition from the program code determines entry points in the program. The code is followed, or scanned, from an entry point to a branch or jump instruction, or control flow instruction. A code block is then defined as the code from the entry point up to and including the control flow instruction. From the control flow instruction, additional entry points are identified. This is repeated for each entry point having a known value, resulting in a partial control flow definition. For entry points having unknown values, a constant propagation analysis is performed on the partial control flow definition to convert unknown entry point values to known values. Finally, the entry points determined by the constant propagation analysis are used as starting points in the scanning step to define additional entry points.

Abstract: A type mismatch problem in computer programs is said to occur when there is a mismatch between the form or classification of a value encountered during program execution and that anticipated by the program. A method for repairing or testing for many type mismatch problems in programs works by transforming a binary representation of the program into a new binary in which the problem is fixed or identified. The fix or identification is implemented by converting code that operates on variables that can suffer a mismatch into code that correctly accounts for or tests for the mismatch. Static or dynamic correlation methods, and/or control and data flow graphs are used to track certain values, to determine where to install patches and how to adjust branch, jump and procedure call references after patch installation has shifted the target references.

Abstract: A type mismatch problem in computer programs is said to occur when there is a mismatch between the form or classification of a value encountered during program execution and that anticipated by the program. A method for repairing or testing for many type mismatch problems in programs works by transforming a binary representation of the program into a new binary in which the problem is fixed or identified. The fix or identification is implemented by converting code that operates on variables that can suffer a mismatch into code that correctly accounts for or tests for the mismatch. Static or dynamic correlation methods, and/or control and data flow graphs are used to track certain values, to determine where to install patches and how to adjust branch, jump and procedure call references after patch installation has shifted the target references.