Module Memory.Pointer_sentinel

Abstraction of pointer arrays by segmentation using a NULL/INVALID sentinel.

This abstract domain divides an array of pointers into three segments:

+-------------------+-+-------------+ | before |S| after | +-------------------+-+-------------+

• The segment "before" represents pointers before the sentinel. All these pointers are different than NULL. The domains maintains a smash variable "before-sentinel" for approximating these values.

• The array cell "S" represents a cell that *may be* NULL. The domain uses the numeric variable "sentinel" and the pointer variable "at-sentinel" to represent the position and the value of the sentinel respectively.

• The segment "after" represents pointers after the sentinel. The domain keeps no information about it.