#1243 [patch] Performance improvement for JSR305 analysis with big inheritance hierarchies

[Tobias Baum]

As FindBugs is currently on the critical chain of our CI build, I did some profiling, which showed that a lot of time is spent in Subtypes2.traverseSupertypes, which is called for JSR305 analysis. This method implements a quite complex algorithm that visits every PATH in the supertype hierarchy. I could not see any reason in the JSR305 code why a simple depth first traversal of every supertype node shouldn't be sufficient. I implemented this as a patch, which gave me a speedup from 3:30 min to 3:00 min for the analysis of our codebase. You can pull my changes from https://code.google.com/r/tbaum-findbugs/

Some further notes:

• I did this change without fully understanding the JSR305 code, so perhaps I missed something. But the unit tests gave the same results before and after, and analysis of our codebase did so, too.
• According to Eclipse, there are no users of Subtypes2.traverseSupertypes left, so perhaps it could be deleted. I kept it anyway and made a new method (and interface) for the changes to keep compatibility with third party plugins.
• We have quite complex interface inheritance hierarchies in some of our generated code, which is probably why this is a performance problem for us (and most of the world was fine with the old implementation).

And finally the formal pull request generated by TortoiseGit:

The following changes since commit 387670322ff17cbc3c38ac932032787905d2ff40:

  Change jsr305/Analysis to more efficient traversal (2014-01-18 17:39:02 +0100)

are available in the git repository at:

  https://code.google.com/r/tbaum-findbugs/ master

for you to fetch changes up to 387670322ff17cbc3c38ac932032787905d2ff40:

  Change jsr305/Analysis to more efficient traversal (2014-01-18 17:39:02 +0100)

----------------------------------------------------------------

[Andrey Loskutov]

I've merged the code.

The FB test execution time with this patch decreased from 5:50 to 5:10 seconds on my workstation.

https://code.google.com/p/findbugs/source/detail?r=25e04a4256e6b47b28853df067f7fc695bf8dcdd

Thanks for the patch!

Regards,
Andrey