1. A method for event-driven observability enhanced coverage analysis of a program, comprising: parsing a program into variables and data dependencies, wherein the data dependencies comprise assignments and operations; loading a data structure based on the parsed program, wherein the data structure comprises a plurality of records and wherein each record comprises at least one of the data dependencies, a parent node, and a child node, wherein each node is linked to one of the variables; computing the value of each variable using the data structure; and performing tag propagation based, at least in part, on the data dependencies and computed values.