  Dynamic programming languages, such as PHP, JavaScript, and Python, provide
built-in data structures including associative arrays and objects with similar
semantics-object properties can be created at run-time and accessed via
arbitrary expressions. While a high level of security and safety of
applications written in these languages can be of a particular importance
(consider a web application storing sensitive data and providing its
functionality worldwide), dynamic data structures pose significant challenges
for data-flow analysis making traditional static verification methods both
unsound and imprecise. In this paper, we propose a sound and precise approach
for value and points-to analysis of programs with associative arrays-like data
structures, upon which data-flow analyses can be built. We implemented our
approach in a web-application domain-in an analyzer of PHP code.
