  The aliasing question (can two reference expressions point, during an
execution, to the same object?) is both one of the most critical in practice,
for applications ranging from compiler optimization to programmer verification,
and one of the most heavily researched, with many hundreds of publications over
several decades. One might then expect that good off-the-shelf solutions are
widely available, ready to be plugged into a compiler or verifier. This is not
the case. In practice, efficient and precise alias analysis remains an open
problem.
  We present a practical tool, AutoAlias, which can be used to perform
automatic alias analysis for object-oriented programs. Based on the theory of
"duality semantics", an application of Abstract Interpretation ideas, it is
directed at object-oriented languages and has been implemented for Eiffel as an
addition to the EiffelStudio environment. It offers variable-precision
analysis, controllable through the choice of a constant that governs the number
of fix point iterations: a higher number means better precision and higher
computation time.
  All the source code of AutoAlias, as well as detailed results of analyses
reported in this article, are publicly available. Practical applications so far
have covered a library of data structures and algorithms and a library for GUI
creation. For the former, AutoAlias achieves a precision appropriate for
practical purposes and execution times in the order of 25 seconds for about
8000 lines of intricate code. For the GUI library, AutoAlias produces the alias
analysis in around 232 seconds for about 150000 lines of intricate code.
