59 research outputs found
CTL+FO Verification as Constraint Solving
Expressing program correctness often requires relating program data
throughout (different branches of) an execution. Such properties can be
represented using CTL+FO, a logic that allows mixing temporal and first-order
quantification. Verifying that a program satisfies a CTL+FO property is a
challenging problem that requires both temporal and data reasoning. Temporal
quantifiers require discovery of invariants and ranking functions, while
first-order quantifiers demand instantiation techniques. In this paper, we
present a constraint-based method for proving CTL+FO properties automatically.
Our method makes the interplay between the temporal and first-order
quantification explicit in a constraint encoding that combines recursion and
existential quantification. By integrating this constraint encoding with an
off-the-shelf solver we obtain an automatic verifier for CTL+FO
Modular Termination Proofs of Recursive Java Bytecode Programs by Term Rewriting
In earlier work we presented an approach to prove termination of
non-recursive Java Bytecode (JBC) programs automatically. Here,
JBC programs are first transformed to finite termination graphs
which represent all possible runs of the program.
Afterwards, the termination graphs are translated to term
rewrite systems (TRSs) such that termination of the resulting TRSs
implies termination of the original JBC programs. So in this way,
existing techniques and tools from term rewriting can be used to
prove termination of JBC automatically. In this paper, we improve
this approach substantially in two ways:
(1) We extend it in order to also analyze recursive JBC programs.
To this end, one has to represent call stacks of arbitrary
size.
(2) To handle JBC programs with several methods, we modularize our
approach in order to re-use termination graphs and TRSs for the
separate methods and to prove termination of the resulting TRS
in a modular way.
We implemented our approach in the tool AProVE. Our experiments show
that the new contributions increase the power of termination analysis
for JBC significantly
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