[PATCH] D144730: [FlowSensitive] Log analysis progress for debugging purposes

[Artem Dergachev via Phabricator via cfe-commits]

NoQ added a comment.

I love such debugging facilities! They're a massive boost to developer productivity compared to ad-hoc debug prints, and they allow new contributors to study how the tool works. I'm excited to see how this thing turns out.

In the static analyzer's path-sensitive engine we've settled on a Graphviz printout of the analysis graph, with an extra python script to filter and "prettify" it. In our case these graphs are much larger than CFGs (on real-world code they often contain over 200000 nodes) so filtering and searching becomes essential. And we usually don't have an option to debug a reduced toy example, because it's typically very hard to define the notion of "false positive" in a way suitable for a `creduce` predicate, and even when reducing manually it's easy to miss the point entirely and end up with a completely different problem. So we had to learn how to deal with these massive graphs, and these days we're pretty good at that. In your case the graphs probably aren't that massive, but other considerations probably still apply.

I found textual CFG dumps of real-world functions to be very hard to read; it's annoying to figure out in which order you're supposed to read the blocks. Most of the time I prefer Graphviz dumps of the CFG. If you're stuck with real-world code as much as we are in the static analyzer, it might be very convenient to somehow include a graphical representation of the CFG alongside your reports. Given that CFGs are relatively small, you might be able to get away with an ad-hoc graph visualizer scripted into your HTML page, so that to avoid relying on Graphviz.

Then I guess you can try adding your abstract state information directly to the graphical CFG blocks, and build a timeline of such partially analyzed CFGs, from the starting state to the fully converged state, brightly highlighting changes made on every step 🤔Dunno, just dreaming at this point.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D144730/new/

https://reviews.llvm.org/D144730