Programming MPSoC platforms: Road works ahead

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

User-centered Program Analysis Tools

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