CSR-EHS: Virtual-Machine Techniques for Resource-Constrained Devices: Reconciling Reliability With Reusability and Low Development Costs in the Embedded Systems Space

虚拟机(VM)是广泛使用的基于计算机的执行框架，其将应用程序与底层硬件和系统软件平台隔离，并实现编程语言运行时语义。该项目的重点是通过跟踪驱动的动态编译在资源受限的设备上高效执行虚拟机代码。许多在图上执行成本很高的优化算法可以在迹上以线性时间执行。此外，跟踪导向的编译器可以以一种直接的方式内联方法调用，在最关键的地方显著减少面向对象编程的模块化开销。因此，这种方法为嵌入式软件中良好的软件工程实践和面向组件的编程铺平了道路，而不会伴随着与这些技术相关的性能损失。该项目基于一种新的静态单一分配表的使用，初步结果为嵌入式混合虚拟机的设计指明了一条全新的道路。主要关注的是系统地探索和进一步开发这种方法，最初目标是Java虚拟机(JVM)平台。第二个重点是开发可扩展的虚拟机层，该层位于支持各种嵌入式软件的最佳位置，但仍可有效地映射到当前和未来的嵌入式处理器平台上。嵌入式系统呈现了一种“一次编写，永远运行”计算范例的应用，但尚未发挥其真正的潜力。该项目预计将导致嵌入式软件开发方式的重大改进。它将使嵌入式软件能够在目前无法重复使用的情况下重新使用，并简化向日益发展的嵌入式处理器的过渡。预计这将对显著降低成本和显著提高嵌入式软件的可靠性产生影响。

Virtual machines (VMs) are widely-used computer-based execution frameworks that isolate an application from the underlying hardware and system software platform and implement programming language run-time semantics.. This project focuses on efficient execution of virtual machine code on resource-constrained devices by way of trace-driven dynamic compilation. Many optimization algorithms that are expensive to perform on graphs can be performed in linear time on a trace. Furthermore, a trace-directed compiler can in-line method calls in a straightforward manner, significantly reducing the modularization overhead of object-oriented programming where it is most critical. This approach thereby paves the way for good software engineering practice and component-oriented programming in embedded software without the accompanying performance penalties that are often associated with these techniques. The project is founded on a novel use of Static Single Assignment form and preliminary results point the way to a completely new way of designing embedded hybrid VMs. The main focus is on systematically exploring and further developing this approach, initially targeting the Java Virtual Machine (JVM) platform. A second focus is on developing a scalable VM layer that is optimally situated to support a wide variety of embedded software, but that can yet be efficiently mapped onto current and future embedded processor platforms. Embedded systems present an application of the 'write once, run forever after' computing paradigm that has not yet reached its true potential. The project is expected to lead to significant improvements in the way embedded software is developed. It will enable reuse of embedded software where no such reuse is currently possible and simplify the transition to increasingly evolved embedded processors. This is expected to have impact in significantly lower cost and significantly increased reliability of embedded software.