International Business Machines Corporation

Kendrick Wong

Cary Lee Bates

Alan S Boxall

Roger Harry Pett

Visualization of synchronization points in modified program source code includes identifying the synchronization points in a program source code segment. The identification is performed in response to a modification of the program source code segment. The visualization of the synchronization points also includes storing line numbers of the synchronization points and line contents corresponding to text located at stored line numbers in the program source code segment. The visualization of the synchronization points further includes implementing, as part of a debugging session: retrieving the synchronization points and the line contents, displaying the line contents of the synchronization points on a display screen, and providing a user with an option to step through the synchronization points in the program source code while skipping the remaining portions of the program source code segment. Displaying the line contents includes visually differentiating the synchronization points from remaining portions of the program source code segment.

Synchronization point visualization for modified program source code

Embodiments of the invention include a method for setting snapshots in code. The method may occur during the debug of code and may include determining whether to place a snapshot instruction immediately before a machine instruction within a module. The determination may include analyzing parameters associated with the machine instruction.

Determining snapshot placement

A method, computer-readable storage medium, and computer system are provided. In an embodiment, a command is received that specifies a debug compile option and requests a compile of a module into object code. If the debug compile option specifies a first debug compile option, snapshot instructions are inserted immediately prior to each machine instruction in the object code at which a breakpoint was previously set. If the debug compile option specifies the first debug compile option, snapshot instructions are inserted immediately prior to each machine instruction in the object code that implements a control flow statement.

Setting breakpoints in optimized instructions

A method, computer-readable storage medium, and computer system are provided. In an embodiment, in response to a command that requests setting a breakpoint at a line in a module, a determination is made whether a snapshot instruction exists before a machine instruction that implements a source statement at the line. If the snapshot instruction exists before the machine instruction that implements the source statement at the line, the breakpoint is set at the machine instruction that implements the source statement at the line. If the snapshot instruction does not exist before the machine instruction that implements the source statement at the line, the module is recompiled to add the snapshot instruction before the machine instruction that implements the source statement.

A mechanism is provided in a debugger for building a file information database while significantly reducing debug startup time. For each line number table, the mechanism of the present invention reads the header section and determines all the source files that contribute to the line number table. The mechanism also makes note of the line number table offset. The mechanism then inserts the source filename into the file information database. In one preferred embodiment, the file information database is implemented as a hash table. Searching time occurs during an interactive debug session; therefore, the searching time is not easily detectable to a user, thus creating the perception of a faster interactive debugging session.

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Toronto, Canada

Kendrick Wong