US Patent 7526756 Address watch breakpoints with basing pointers

A method, apparatus, system, and signal-bearing medium that, in an embodiment, receive a request for an address watch breakpoint to a variable, determine that the variable is referenced via a basing pointer expression, and monitor for initialization of the basing pointer prior to monitor for a change to the contents of the variable that is pointed to by the basing pointer expression. In an embodiment, the basing pointer expression is implemented as an instruction that uses an indirect addressing mode. In an embodiment, the basing pointer is determined to be uninitialized, and thus needs monitoring for initialization, by detecting an error that results from adding an offset for the variable to the contents of the basing pointer, or by detecting an error when the result of the adding is used as a pointer. In an embodiment, the basing pointer expression comprises a plurality of basing pointers, each of which is monitored for initialization in turn. In this way, the user is freed from the difficulty involved in attempting to determine where and if the basing pointer is set prior to monitoring for a modification to a variable that is pointed to by the basing pointer.