1506868 - Mitigate TSan false positives for thread-safe refcounting

Status: RESOLVED FIXED

(Core :: XPCOM, enhancement)

Description

[Yaron Tausky [:ytausky]]

TSan doesn't support std::atomic_thread_fence, so this line causes a lot of noise when using it: https://searchfox.org/mozilla-central/source/xpcom/base/nsISupportsImpl.h#358
Replacing the fence with an atomic load-acquire when building with -fsanitize=thread clears up the output and is more resilient than simply suppressing the error message.

Comment 1

[Yaron Tausky [:ytausky]]

Attachment: Bug 1506868: Replace calls to std::atomic_thread_fence in TSan mode

TSan doesn't support std::atomic_thread_fence, so in order to avoid noisy
output, we can replace the fence with an atomic load when building with
-fsanitize=thread. This is a better alternative than error message
suppression since it's closer to the relevant code and thus much likelier
to survive changes to it.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/030c33c24d8c
Replace calls to std::atomic_thread_fence in TSan mode r=froydnj

Comment 3

[Cristina Coroiu [:ccoroiu]]

https://hg.mozilla.org/mozilla-central/rev/030c33c24d8c