Bug 68910 – Would like an EWS bot that runs the Clang static analyzer on patches

• Status: NEW
• Component: Tools / Tests

[Adam Roben (:aroben)]

It would be great to have an EWS bot that ran patches through the Clang static analyzer. Then we could find issues even before the patch is landed!

[Radar WebKit Bug Importer]

<rdar://problem/10193189>

[Adam Barth]

How do I run the clang static analyzer?

[Adam Roben (:aroben)]

There are generic instructions on <http://clang-analyzer.llvm.org/scan-build.html>. I'm not sure what the specific process would be for WebKit.

[Adam Roben (:aroben)]

See also bug 68908.

[Adam Barth]

Thakis is working on switching the webkit.org build of Chromium Mac to use clang, which seems related.  (The chromium.org version already uses clang.)

I'm pretty ignorant about this topic, but I think that will help here.

[Adam Roben (:aroben)]

I wonder if something as simple as "scan-build build-webkit" would work?

[Adam Barth]

abarth@quadzen:~/svn/webkit$ scan-build build-webkit
-bash: scan-build: command not found

^^^ Maybe I need Lion?

[Adam Roben (:aroben)]

I don't seem to have a "scan-build" binary either.

I do notice that clang supports an --analyze flag.

I guess we should figure out how Xcode drives clang for static analysis.

[Adam Roben (:aroben)]

It looks like Xcode is just calling "clang --analyze" (with loads of other options appropriate for the project, of course).

[Anders Carlsson]

scan-build is just a perl script - it's available from the clang svn repository.

[Adam Roben (:aroben)]

Supposedly this will do it (for a single project, of course): xcodebuild RUN_CLANG_STATIC_ANALYZER=YES

[Adam Roben (:aroben)]

See also bug 68908.

[Nico Weber]

scan-build isn't distributed anywhere I know of, but it can be checked out from the clang svn repo here: http://llvm.org/viewvc/llvm-project/cfe/trunk/tools/scan-build/

As of 2011-11-30, the analyzer doesn't understand RAII and smart pointers ( http://llvm.org/bugs/show_bug.cgi?id=11425#c1 ), which makes it not very useful for c++ projects in my experience. As far as I know, this is still true today.

[Mark Rowe (bdash)]

It's distributed as part of Xcode, and is incredibly effective at finding issues in code that makes use of Objective-C and CF. It's effectiveness in C++ code will only increase over time.

[Adam Barth]

If it's a Mac thing, then it should be straightforward to run on the mac-ews.  Sorry for the ignorant question, but does "xcodebuild RUN_CLANG_STATIC_ANALYZER=YES" generate a compiled binary, or just run the analysis?  If the analysis step is separate, we might want to run the analysis on separate bots to avoid slowing down the mac-ews.

[Mark Rowe (bdash)]

It both compiles and runs the analysis.

[Adam Barth]

Ok.  Maybe the thing to do is to add a --analyze flag to build-webkit that runs the analysis together with building.

thakis warned me in IRC that the static analysis can be much slower than the normal compile, so we'll want to make sure we have enough machine bandwidth.

[Alexey Proskuryakov]

Technically, we have a static analyzer bot now, but with very focused coverage that doesn't fulfill the intention of this bug.