731853 - add easy way to do shutdown WANT_ALL_TRACES CC logging

Status: RESOLVED FIXED

(Core :: XPCOM, defect)

Description

[Andrew McCreight [:mccr8]]

The most common kind of leak hunting is looking at shutdown leaks.  It would be handy if there was an easy way to
a) log only shutdown CCs, as that's often all you care about for shutdown leaks
b) make them WANT_ALL_TRACES, as this is needed if the leak is in JS (as it often is...)

For this bug, at first I'll just try out a compile flag in nsCycleCollector.cpp.  If we want to get fancy later we can add an environment flag in debug builds or something.

Comment 1

[Andrew McCreight [:mccr8]]

Attachment: add two globals to control shutdown logging

I haven't tested this, but it does compile. I add two boolean flags at the top of nsCycleCollector.cpp. One will log all shutdown CCs, the other will make all shutdown CCs AllTraces(). Shutdown CCs always do a GC beforehand, so we don't need to do any further trickery to disable CC optimization.

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

Comment on attachment 665959 [details] [diff] [review]
add two globals to control shutdown logging

It would be nice to be able to control this all using some
prefs or env variables.

Comment 3

[Andrew McCreight [:mccr8]]

That's a good point. I was thinking that myself. I'll figure out how to work that in there.

Comment 4

[Andrew McCreight [:mccr8]]

Hrmph, I guess I never landed this. I'll land it soon and file a followup for a way to trigger this without recompiling.

Comment 5

[Andrew McCreight [:mccr8]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/4fcba9b6e0f8

Filed bug 823226 for controlling logging via environment variables.

Comment 6

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/4fcba9b6e0f8