Understanding a failure from ESan

Hi Derek,

It looks like you committed the efficiency sanitizer a couple of months ago (cool project, BTW). A bot with the efficiency sanitizer recently failed on one of my commits:

It's not exactly clear to me what the error is reporting (full text below). Is it saying I broke the efficiency sanitizer, or that I made clang less efficient?

In either case, this test might be too flakey to be on by default. My recent commits have been NFC (supposedly... could be a bug), so I'm surprised this caused a failure. But if you think I actually broke something I could use some help figuring out which side to investigate.

Thanks for the advice!

FAIL: EfficiencySanitizer-x86_64 :: TestCases/workingset-samples.cpp (12230 of 29483)
******************** TEST 'EfficiencySanitizer-x86_64 :: TestCases/workingset-samples.cpp' FAILED ********************

Ah, nevermind, David Majnemer already has questions on the commit thread:

Please send responses there.