Software-Debug-Tools-and-Methods德尔福嵌入式软件调试方法.ppt

Delphi Business Proprietary Software Debug Debugging Methods Intuition may be the simplest debugging method, but Binary Search is not far behind. Here’s the scenario: We’re releasing version 14.31 to the customer this Friday. My last change to the Cylinder Deac logic was version 14.10, about a month ago. I tested the changes thoroughly, and the logic worked flawlessly. During release checks, I see that the 4 Deac outputs look fine- 180 degrees apart, like they are supposed to be. But they seem to turn on and off at random angles, not as specified in the calibrations. Delphi Business Proprietary Software Debug Debugging Methods 14.31 14.27 14.23 14.19 14.15 14.30 14.26 14.22 14.18 14.14 14.29 14.25 14.21 14.17 14.13 14.28 14.24 14.20 14.16 14.12 14.11 14.10 What do I know? Almost everything. I know the code worked in 14.10, and there were no changes. Approach- Binary Search. Consider the boxes above to represent the releases. 14.10, on the right in green, is known to be good. 14.31, on the left in red, is known to be broken. The releases in yellow are unknown, but we suspect they’re all good, from right to left, until the error was introduced. Delphi Business Proprietary Software Debug Debugging Methods 14.31 14.27 14.23 14.19 14.15 14.30 14.26 14.22 14.18 14.14 14.29 14.25 14.21 14.17 14.13 14.28 14.24 14.20 14.16 14.12 14.11 14.10 We could test each release in turn, from right to left, until we find the problem. Worst case, this would involve 19 builds, and trips to the bench for testing. Binary search lets us identify the error with a maximum of 5 tests (32 or fewer releases). We’ll start with a test of 14.20, and see if it’s proper. Delphi Business Proprietary Software Debug Debugging Methods 14.31 14.27 14.23 14.19 14.15 14.30 14.26 14.22 14.18 14.14 14.29 14.25 14.21 14.17 14.13 14.28 14.24 14.20 14.16 14.12 14.11 14.10 14.20, now marked green, passed the test. We assume that 14.11 to 14.19 were good also- this is not proven, but i