reverse engineering – recent advances and applications - OpenLibra

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Reverse Engineering – Recent Advances and Applications
to variables, attributes or their use in messages (method invocations). OFG is defined as an
oriented graph that represents all data flows linking objects.
The static analysis is data flow sensitive, but control flow insensitive. This means that
programs with different control flows and the same data flows are associated with the same
analysis results. The choice of this program representation is motivated by the
computational complexity of the involved algorithms. On the one hand, control flow
sensitive analysis is computationally intractable and on the other hand, data flow sensitive
analysis is aligned to the “nature” of the object-oriented programs whose execution models
impose more constraints on the data flows than on the control flows. For example, the
sequence of method invocations may change when moving from an application which uses
a class to another one, while the possible ways to copy and propagate object references
remains more stable.
A consequence of the control flow insensitivity is that the construction of the OFG can be
described with reference to a simplified, abstract version of the object-oriented languages in
which instructions related to flow control are ignored. A generic algorithm of flow
propagation working on the OFG processes object information. In the following, we
describe the three essential components of the common analysis framework: the simplified
abstract object-oriented language, the data flow graph and the flow propagation algorithm.
Fig. 3. Static and dynamic analysis