50 research outputs found

    Sindarin: A Versatile Scripting API for the Pharo Debugger

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    International audienceDebugging is one of the most important and time consuming activities in software maintenance, yet mainstream debuggers are not well-adapted to several debugging scenarios. This has led to the research of new techniques covering specific families of complex bugs. Notably, recent research proposes to empower developers with scripting DSLs, plugin-based and moldable debuggers. However, these solutions are tailored to specific use-cases, or too costly for one-time-use scenarios. In this paper we argue that exposing a debugging scripting interface in mainstream debuggers helps in solving many challenging debugging scenarios. For this purpose, we present Sindarin, a scripting API that eases the expression and automation of different strategies developers pursue during their debugging sessions. Sindarin provides a GDB-like API, augmented with AST-bytecode-source code mappings and object-centric capabilities. To demonstrate the versatility of Sindarin, we reproduce several advanced breakpoints and non-trivial debugging mechanisms from the literature

    Programming MPSoC platforms: Road works ahead

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    This paper summarizes a special session on multicore/multi-processor system-on-chip (MPSoC) programming challenges. The current trend towards MPSoC platforms in most computing domains does not only mean a radical change in computer architecture. Even more important from a SW developer´s viewpoint, at the same time the classical sequential von Neumann programming model needs to be overcome. Efficient utilization of the MPSoC HW resources demands for radically new models and corresponding SW development tools, capable of exploiting the available parallelism and guaranteeing bug-free parallel SW. While several standards are established in the high-performance computing domain (e.g. OpenMP), it is clear that more innovations are required for successful\ud deployment of heterogeneous embedded MPSoC. On the other hand, at least for coming years, the freedom for disruptive programming technologies is limited by the huge amount of certified sequential code that demands for a more pragmatic, gradual tool and code replacement strategy

    Doctor of Philosophy

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    dissertationDomain-specific languages (DSLs) are increasingly popular, and there are a variety of ways to create a DSL. A DSL designer might write an interpreter from scratch, compile the DSL to another language, express DSL concepts using only the existing forms of an existing language, or implement DSL constructs using a language's extension capabilities, including macros. While extensible languages can offer the easiest opportunity for creating a DSL that takes advantage of the language's existing infrastructure, existing tools for debugging fail to adequately adapt the debugging experience to a given domain. This dissertation addresses the problem of debugging DSLs defined with macros and describes an event-oriented approach that works well with a macro-expansion view of language implementation. It pairs the mapping of DSL terms to host terms with an event mapping to convert primitive events back to domain-specific concepts. Domain-specific events can be further inspected or manipulated to construct domain-specific debuggers. This dissertation presents a core model of evaluation and events and also presents a language design-analogous to pattern-based notations for macros, but in the other direction-for describing how events in a DSL's expansion are mapped to events at the DSL's level. The domain-specific events can enable useful, domain-specific debuggers, and the dissertation introduces a design for a debugging framework to help with debugger construction. To validate the design of the debugging framework, a debugging framework, Ripple, is implemented, and this dissertation demonstrates that with a modest amount of work, Ripple can support building domain-specific debuggers

    User-centered Program Analysis Tools

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    The research and industrial communities have made great strides in developing advanced software defect detection tools based on program analysis. Most of the work in this area has focused on developing novel program analysis algorithms to find bugs more efficiently or accurately, or to find more sophisticated kinds of bugs. However, the focus on algorithms often leads to tools that are complex and difficult to actually use to debug programs. We believe that we can design better, more useful program analysis tools by taking a user-centered approach. In this dissertation, we present three possible elements of such an approach. First, we improve the user interface by designing Path Projection, a toolkit for visualizing program paths, such as call stacks, that are commonly used to explain errors. We evaluated Path Projection in a user study and found that programmers were able to verify error reports more quickly with similar accuracy, and strongly preferred Path Projection to a standard code viewer. Second, we make it easier for programmers to combine different algorithms to customize the precision or efficiency of a tool for their target programs. We designed Mix, a framework that allows programmers to apply either type checking, which is fast but imprecise, or symbolic execution, which is precise but slow, to different parts of their programs. Mix keeps its design simple by making no modifications to the constituent analyses. Instead, programmers use Mix annotations to mark blocks of code that should be typed checked or symbolically executed, and Mix automatically combines the results. We evaluated the effectiveness of Mix by implementing a prototype called Mixy for C and using it to check for null pointer errors in vsftpd. Finally, we integrate program analysis more directly into the debugging process. We designed Expositor, an interactive dynamic program analysis and debugging environment built on top of scripting and time-travel debugging. In Expositor, programmers write program analyses as scripts that analyze entire program executions, using list-like operations such as map and filter to manipulate execution traces. For efficiency, Expositor uses lazy data structures throughout its implementation to compute results on-demand, enabling a more interactive user experience. We developed a prototype of Expositor using GDB and UndoDB, and used it to debug a stack overflow and to unravel a subtle data race in Firefox

    Practical domain-specific debuggers using the Moldable Debugger framework

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    International audienceUnderstanding the run-time behavior of software systems can be a challenging activity. Debuggers are an essential category of tools used for this purpose as they give developers direct access to the running systems. Nevertheless, traditional debuggers rely on generic mechanisms to introspect and interact with the running systems, while developers reason about and formulate domain-specific questions using concepts and abstractions from their application domains. This mismatch creates an abstraction gap between the debugging needs and the debugging support leading to an inefficient and error-prone debugging effort, as developers need to recover concrete domain concepts using generic mechanisms. To reduce this gap, and increase the efficiency of the debugging process, we propose a framework for developing domain-specific debuggers, called the Moldable Debugger, that enables debugging at the level of the application domain. The Moldable Debugger is adapted to a domain by creating and combining domain-specific debugging operations with domain-specific debugging views, and adapts itself to a domain by selecting, at run time, appropriate debugging operations and views. To ensure the proposed model has practical applicability (i.e., can be used in practice to build real debuggers), we discuss, from both a performance and usability point of view, three implementation strategies. We further motivate the need for domain-specific debugging, identify a set of key requirements and show how our approach improves debugging by adapting the debugger to several domains

    Checking-in on Network Functions

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    When programming network functions, changes within a packet tend to have consequences---side effects which must be accounted for by network programmers or administrators via arbitrary logic and an innate understanding of dependencies. Examples of this include updating checksums when a packet's contents has been modified or adjusting a payload length field of a IPv6 header if another header is added or updated within a packet. While static-typing captures interface specifications and how packet contents should behave, it does not enforce precise invariants around runtime dependencies like the examples above. Instead, during the design phase of network functions, programmers should be given an easier way to specify checks up front, all without having to account for and keep track of these consequences at each and every step during the development cycle. In keeping with this view, we present a unique approach for adding and generating both static checks and dynamic contracts for specifying and checking packet processing operations. We develop our technique within an existing framework called NetBricks and demonstrate how our approach simplifies and checks common dependent packet and header processing logic that other systems take for granted, all without adding much overhead during development.Comment: ANRW 2019 ~ https://irtf.org/anrw/2019/program.htm
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