Platinum: Reusing Constraint Solutions in Bounded Analysis of Relational Logic

Abstract

Alloy is a lightweight specification language based on relational logic, with an analysis engine that relies on SAT solvers to automate bounded verification of specifications. In spite of its strengths, the reliance of the Alloy Analyzer on computationally heavy solvers means that it can take a significant amount of time to verify software properties, even within limited bounds. This challenge is exacerbated by the ever-evolving nature of complex software systems. This paper presents PLATINUM, a technique for efficient analysis of evolving Alloy specifications, that recognizes opportunities for constraint reduction and reuse of previously identified constraint solutions. The insight behind PLATINUM is that formula constraints recur often during the analysis of a single specification and across its revisions, and constraint solutions can be reused over sequences of analyses performed on evolving specifications. Our empirical results show that PLATINUM substantially reduces (by 66.4% on average) the analysis time required on specifications extracted from real-world software systems.

Incremental Verification of UML/OCL Models.

“…The major contribution of our proposed method is that it is not limited to reusing the results of the analysis of the original specification, as (Wang et al 2019;Zheng et al 2020) Instead, whenever a change is performed to the original class diagram, we will query and update the certificate to make sure it still proves the satisfiability of the updated model, avoiding new calls to the model finder whenever possible. Notice that some actions such as checking if an OCL constraint holds in a certificate do not require invoking the model finder and can be thus performed much more efficiently.…”

“…Nevertheless, few approaches have considered the incremental verification of a declarative model after a set of changes in the model. In this section, we describe three of the closest ones to our approach, which are defined in the context of Alloy: Titanium (Bagheri & Malek 2016), iAlloy (Wang et al 2019) and Platinum (Zheng et al 2020).…”

“…Platinum (Zheng et al 2020) is another extension of the Alloy Analyzer to support evolving specifications. It allows reusing checks performed in previous versions of the specification (whole or parts).…”

REACH: Refining Alloy Scenarios by Scope

“…Second, iAlloy uses static analysis to determine which commands to avoid re-executing and determine which scenarios to reuse, with a focus on formula level changes [36]. Third, Platinum slices Alloy models at a boolean level using the CNF formula and reuses scenarios if a redundant CNF slice is detected, and focuses on model structure changes [37]. All three efforts are intended to be more generic than Reach, working with a broader range of incremental changes.…”

Coupling solvers with model transformations to generate explorable model sets

“…We were surprised to observe that the JavaFX rendering algorithm was indeed the limiting factor for large interactive diagrams. Incremental solvers are not common but new approaches, such as [45], add incrementality to existing solvers.…”