A Fully Capable Bidirectional Debugger

传统的调试器允许沿着计算机程序的正向执行路径步进，并在程序执行时监视程序的状态。它们是程序开发过程中的一个重要工具，但是在许多情况下，当用户希望看到的不是程序将来会做什么，而是过去发生了什么，使它达到当前的位置时，它们也会令人沮丧。本研究将探讨并发展可用于建构双向程式侦错器的演算法与机制。有效的向后移动算法将研究所有传统的向前移动操作：步骤，下一步，完成，和位置断点。在这项研究中，预计将利用和开发的底层技术是代码增强，透明的重新执行，I/O重放和检查点。此外，本研究将研究有效的双向算法的条件断点和数据断点，这是目前往往是低效的操作或不可用，即使在前进的方向。从入门编程的学生试图理解为什么他们的程序已经误入歧途，到专业程序员试图在大型复杂系统中找到bug，都广泛使用了bug检测器。开发更好的调试工具将使所有参与程序开发和维护的人受益。 ***

9619456 Traditional debuggers allow stepping along the forward execution path of a computer program and monitoring the program's state as it executes. They are a crucial tool in the process of program development, however they also can be frustrating in many situations when the user wishes to see not what the program is going to do in the future, but rather what happened in the past to bring it to where it currently is. This research will investigate and develop algorithms and mechanisms that can be used in constructing a bidirectional program debugger. Efficient backwards movement algorithms will be investigated for all traditional forward movement operations: step, next, finish, and location breakpoints. The underlying techniques expected to be utilized and developed in this research are code augmentation, transparent re-execution, I/O replay, and checkpointing. In addition, this research will investigate efficient bidirectional algorithms for conditional breakpoints and data breakpoints, which are currently often inefficient operations or unavailable even in the forward direction. Debuggers are widely used from introductory programming students trying to understand why their program has gone astray, to professional programmers trying to find bugs in large and complicated systems. Development of better debugging tools will benefit all who are involved in program development and maintenance. ***