98 research outputs found
Entailment Checking in Separation Logic with Inductive Definitions is 2-EXPTIME hard
The entailment between separation logic formulae with inductive predicates,
also known as symbolic heaps, has been shown to be decidable for a large class
of inductive definitions. Recently, a 2-EXPTIME algorithm was proposed and an
EXPTIME-hard bound was established; however no precise lower bound is known. In
this paper, we show that deciding entailment between predicate atoms is
2-EXPTIME-hard. The proof is based on a reduction from the membership problem
for exponential-space bounded alternating Turing machines
Deciding Entailments in Inductive Separation Logic with Tree Automata
Separation Logic (SL) with inductive definitions is a natural formalism for
specifying complex recursive data structures, used in compositional
verification of programs manipulating such structures. The key ingredient of
any automated verification procedure based on SL is the decidability of the
entailment problem. In this work, we reduce the entailment problem for a
non-trivial subset of SL describing trees (and beyond) to the language
inclusion of tree automata (TA). Our reduction provides tight complexity bounds
for the problem and shows that entailment in our fragment is EXPTIME-complete.
For practical purposes, we leverage from recent advances in automata theory,
such as inclusion checking for non-deterministic TA avoiding explicit
determinization. We implemented our method and present promising preliminary
experimental results
Foundations for decision problems in separation logic with general inductive predicates
Abstract. We establish foundational results on the computational com-plexity of deciding entailment in Separation Logic with general induc-tive predicates whose underlying base language allows for pure formulas, pointers and existentially quantified variables. We show that entailment is in general undecidable, and ExpTime-hard in a fragment recently shown to be decidable by Iosif et al. Moreover, entailment in the base language is Î P2-complete, the upper bound even holds in the presence of list predicates. We additionally show that entailment in essentially any fragment of Separation Logic allowing for general inductive predicates is intractable even when strong syntactic restrictions are imposed.
Model checking for symbolic-heap separation logic with inductive predicates
We investigate the model checking problem for symbolic-heap separation logic with user-defined inductive predicates, i.e., the problem of checking that a given stack-heap memory state satisfies a given formula in this language, as arises e.g. in software testing or runtime verification.
First, we show that the problem is decidable; specifically, we present a bottom-up fixed point algorithm that decides the problem and runs in exponential time in the size of the problem instance.
Second, we show that, while model checking for the full language is EXPTIME-complete, the problem becomes NP-complete or PTIME-solvable when we impose natural syntactic restrictions on the schemata defining the inductive predicates. We additionally present NP and PTIME algorithms for these restricted fragments.
Finally, we report on the experimental performance of our procedures on a variety of specifications extracted from programs, exercising multiple combinations of syntactic restrictions
Model checking for symbolic-heap separation logic with inductive predicates
We investigate the *model checking* problem for symbolic-heap separation logic with user-defined inductive predicates, i.e., the problem of checking that a given stack-heap memory state satisfies a given formula in this language, as arises e.g. in software testing or runtime verification. First, we show that the problem is *decidable*; specifically, we present a bottom-up fixed point algorithm that decides the problem and runs in exponential time in the size of the problem instance. Second, we show that, while model checking for the full language is EXPTIME-complete, the problem becomes NP-complete or PTIME-solvable when we impose natural syntactic restrictions on the schemata defining the inductive predicates. We additionally present NP and PTIME algorithms for these restricted fragments. Finally, we report on the experimental performance of our procedures on a variety of specifications extracted from programs, exercising multiple combinations of syntactic restrictions
A decision procedure for satisfiability in separation logic with inductive predicates
We show that the satisfiability problem for the "symbolic heap" fragment of separation logic with general inductively defined predicates - which includes most fragments employed in program verification - is decidable. Our decision procedure is based on the computation of a certain fixed point from the definition of an inductive predicate, called its "base", that exactly characterises its satisfiability.
A complexity analysis of our decision procedure shows that it runs, in the worst case, in exponential time. In fact, we show that the satisfiability problem for our inductive predicates is EXPTIME-complete, and becomes NP-complete when the maximum arity over all predicates is bounded by a constant.
Finally, we provide an implementation of our decision procedure, and analyse its performance both on a synthetically generated set of test formulas, and on a second test set harvested from the separation logic literature. For the large majority of these test cases, our tool reports times in the low milliseconds
On Automated Lemma Generation for Separation Logic with Inductive Definitions
Separation Logic with inductive definitions is a well-known approach for
deductive verification of programs that manipulate dynamic data structures.
Deciding verification conditions in this context is usually based on
user-provided lemmas relating the inductive definitions. We propose a novel
approach for generating these lemmas automatically which is based on simple
syntactic criteria and deterministic strategies for applying them. Our approach
focuses on iterative programs, although it can be applied to recursive programs
as well, and specifications that describe not only the shape of the data
structures, but also their content or their size. Empirically, we find that our
approach is powerful enough to deal with sophisticated benchmarks, e.g.,
iterative procedures for searching, inserting, or deleting elements in sorted
lists, binary search tress, red-black trees, and AVL trees, in a very efficient
way
Reasoning on Dynamic Transformations of Symbolic Heaps
Building on previous results concerning the decidability of the satisfiability and entailment problems for separation logic formulas with inductively defined predicates, we devise a proof procedure to reason on dynamic transformations of memory heaps. The initial state of the system is described by a separation logic formula of some particular form, its evolution is modeled by a finite transition system and the expected property is given as a linear temporal logic formula built over assertions in separation logic
The Lower Bound of Decidable Entailments in Separation Logic with Inductive Definitions
The entailment between separation logic formulae with inductive predicates (also known as symbolic heaps) has been shown to be decidable for a large class of inductive definitions [4]. Recently, a 2EXPTIME algorithm has been proposed [7], however no precise lower bound is known (although a EXPTIME-hard bound for this problem has been established in [5]). In this paper, we show that deciding entailment between predicate atoms is 2EXPTIME-hard. The proof is based on a reduction from the membership problem for exponential-space bounded alternating Turing machines [3]
- …