TuBound - A Conceptually New Tool for Worst-Case Execution Time Analysis

TuBound is a conceptually new tool for the worst-case execution time (WCET) analysis of programs. A distinctive feature of TuBound is the seamless integration of a WCET analysis component and of a compiler in a uniform tool. TuBound enables the programmer to provide hints improving the precision of the WCET computation on the high-level program source code, while preserving the advantages of using an optimizing compiler and the accuracy of a WCET analysis performed on the low-level machine code. This way, TuBound ideally serves the needs of both the programmer and the WCET analysis by providing them the interface on the very abstraction level that is most appropriate and convenient to them. In this paper we present the system architecture of TuBound, discuss the internal work-flow of the tool, and report on first measurements using benchmarks from Maelardalen University. TuBound took also part in the WCET Tool Challenge 2008

WCET Analysis: The Annotation Language Challenge

Worst-case execution time (WCET) analysis is indispensable for the successful design and development of systems, which, in addition to their functional constraints, have to satisfy hard real-time constraints. The expressiveness and usability of annotation languages, which are used by algorithms and tools for WCET analysis in order to separate feasible from infeasible program paths, have a crucial impact on the precision and performance of these algorithms and tools. In this paper, we thus propose to complement the WCET tool challenge, which has recently successfully been launched, by a second closely related challenge: the WCET annotation language challenge. We believe that contributions towards mastering this challenge will be essential for the next major step of advancing the field of WCET analysis

Principles for Value Annotation Languages

Tools for code-level program analysis need formats to express various properties, like relevant properties of the environment where the analysed code will execute, and the analysis results. Different WCET analysis tools typically use tool-specific annotation languages for this purpose. These languages are often geared towards expressing properties that the particular tool can handle rather than being general, and mostly their semantics is only specified informally. This makes it harder for tools to communicate, as well as for users to provide relevant information to them. Here, we propose a small but general assertion language for value constraints including IPET flow facts, which is an important class of annotations for WCET analysis tools. We show how to express interesting properties in this language, we propose some syntactic conveniences, and we give the language a formal semantics. The language could be used directly as a tool-independent annotation language, or as a meta-language to give exact semantics to existing value annotation and flow fact formats

OTAWA: An Open Toolbox for Adaptive WCET Analysis

International audienceThe analysis of worst-case execution times has become mandatory in the design of hard real-time systems: it is absolutely necessary to know an upper bound of the execution time of each task to determine a task schedule that insures that deadlines will all be met. The OTAWA toolbox presented in this paper has been designed to host algorithms resulting from research in the domain of WCET analysis so that they can be combined to compute tight WCET estimates. It features an abstraction layer that decouples the analyses from the target hardware and from the instruction set architecture, as well as a set of functionalities that facilitate the implementation of new approaches

Program Semantics in Model-Based WCET Analysis: A State of the Art Perspective

Advanced design techniques of safety-critical applications use specialized development model based methods. Under this setting, the application exists at several levels of description, as the result of a sequence of transformations. On the positive side, the application is developed in a systematic way, while on the negative side, its high-level semantics may be obfuscated when represented at the lower levels. The application should provide certain functional and non-functional guarantees. When the application is a hard real-time program, such guarantees could be deadlines, thus making the computation of worst-case execution time (WCET) bounds mandatory. This paper overviews, in the context of WCET analysis, what are the existing techniques to extract, express and exploit the program semantics along the model-based development workflow

Programmiersprachen und Rechenkonzepte

Seit 1984 veranstaltet die GI-Fachgruppe "Programmiersprachen und Rechenkonzepte", die aus den ehemaligen Fachgruppen 2.1.3 "Implementierung von Programmiersprachen" und 2.1.4 "Alternative Konzepte für Sprachen und Rechner" hervorgegangen ist, regelmäßig im Frühjahr einen Workshop im Physikzentrum Bad Honnef. Das Treffen dient in erster Linie dem gegenseitigen Kennenlernen, dem Erfahrungsaustausch, der Diskussion und der Vertiefung gegenseitiger Kontakte

A Model-Derivation Framework for Software Analysis

Model-based verification allows to express behavioral correctness conditions like the validity of execution states, boundaries of variables or timing at a high level of abstraction and affirm that they are satisfied by a software system. However, this requires expressive models which are difficult and cumbersome to create and maintain by hand. This paper presents a framework that automatically derives behavioral models from real-sized Java programs. Our framework builds on the EMF/ECore technology and provides a tool that creates an initial model from Java bytecode, as well as a series of transformations that simplify the model and eventually output a timed-automata model that can be processed by a model checker such as UPPAAL. The framework has the following properties: (1) consistency of models with software, (2) extensibility of the model derivation process, (3) scalability and (4) expressiveness of models. We report several case studies to validate how our framework satisfies these properties.Comment: In Proceedings MARS 2017, arXiv:1703.0581

A Model-Derivation Framework for Software Analysis

Model-based verification allows to express behavioral correctness conditions like the validity of execution states, boundaries of variables or timing at a high level of abstraction and affirm that they are satisfied by a software system. However, this requires expressive models which are difficult and cumbersome to create and maintain by hand. This paper presents a framework that automatically derives behavioral models from real-sized Java programs. Our framework builds on the EMF/ECore technology and provides a tool that creates an initial model from Java bytecode, as well as a series of transformations that simplify the model and eventually output a timed-automata model that can be processed by a model checker such as UPPAAL. The framework has the following properties: (1) consistency of models with software, (2) extensibility of the model derivation process, (3) scalability and (4) expressiveness of models. We report several case studies to validate how our framework satisfies these properties.Comment: In Proceedings MARS 2017, arXiv:1703.0581