1465878 - Remove the compile-time "MOZ_DEV_EDITION" check in mozJSComponentLoader.h for STARTUP_RECORDER_ENABLED

Status: NEW

(Core :: XPConnect, enhancement, P2)

Description

[Daniel Holbert [:dholbert]]

Bug 1428176 added a compile-time MOZ_DEV_EDITION check (in mozJSComponentLoader.h), as part of #defining STARTUP_RECORDER_ENABLED.

Per bug 1459240, we'd like to remove compile-time devedition checks, so that devedition can be reborn as a repack of Firefox Beta. (via some sort of post-compilation pref-tweak or reconfiguration)

Can we do that for STARTUP_RECORDER_ENABLED -- i.e. can replace it with a runtime configuration check, at least for the beta channel?

(I haven't dug too far, but based on the naming, I worry that maybe this startup-recorder stuff kicks in before we've gotten a chance to read in config files... but I'm not sure.)

Comment 1

[Daniel Holbert [:dholbert]]

Source link: https://dxr.mozilla.org/mozilla-central/rev/5866d6685849311f057e7e229b9ace63a2641c29/js/xpconnect/loader/mozJSComponentLoader.h#40-42

(In reply to Daniel Holbert [:dholbert] from comment #0)
> Can we do that for STARTUP_RECORDER_ENABLED -- i.e. can replace it with a
> runtime configuration check, at least for the beta channel?

florian or mccr8, I think ^this is a question for you, since you wrote/reviewed the patch on bug 1428176.  (It looks like florian's away for a few days & not accepting "needinfo" at the moment, hence needinfo'ing mccr8 for now.)

Comment 2

[Andrew McCreight [:mccr8]]

It looks reasonable to me. When disabled, it looks like STARTUP_RECORDER_ENABLED adds a string field to ModuleEntry, which seems harmless enough, and also does a pref check. It looks like the pref check was the concern that lead florian to hide this behind a compile flag. I don't have a sense of whether that's likely to be a problem in practice, or if there's a different way we could access the pref that would be faster.

Comment 3

[Andrew McCreight [:mccr8]]

I think Felipe has been looking at startup time recently from the Firefox side, so you could ask him whether checking a pref is something that we need to worry about, speed-wise.