1148214 - Encapsulate AllocKind range checks in a few functions

Status: RESOLVED FIXED

(Core :: JavaScript: GC, defect)

Description

[Emanuel Hoogeveen [:ehoogeveen]]

With all the range-based for loops in place we barely use specific AllocKinds directly anymore except to set a variable or pass into a function. The notable exceptions to this are the various assertions and other range checks we have scattered around to ensure that we're not holding on to some invalid AllocKind.

Comment 1

[Emanuel Hoogeveen [:ehoogeveen]]

Attachment: Replace manual AllocKind range checks with a few centralized functions.

I went with IsValidAllocKind() for the common check of |< AllocKind::LIMIT|, and IsAllocKind() for the less common |<= AllocKind::LIMIT|. AllocKind::LIMIT is obviously a 'valid' AllocKind in some sense, but where we allow it at all, we use it to mean 'not allocated' or 'not initialized'. I put IsValidAllocKind() higher up in Heap.h so people will hopefully see it first and consider which variant they want.

As for the implementation, I chose to go with >= and <= everywhere for consistency, and added back the |>= AllocKind::FIRST| and |>= AllocKind::OBJECT0| parts. Now that the underlying type of AllocKind is |int| again, it makes sense to check for negative values.

Comment 2

[Emanuel Hoogeveen [:ehoogeveen]]

This only depends on bug 1146662 in that it touches the same code, and has to land after that bug.

I did change the assertions in SomeAllocKinds() a bit - checking |first| to make sure it isn't negative, and removing the |first <= limit| check since MakeEnumeratedRange already has an assertion for that.

Comment 3

[Emanuel Hoogeveen [:ehoogeveen]]

Green on try:
https://treeherder.mozilla.org/#/jobs?repo=try&revision=9fe319531276

Comment 4

[Terrence Cole [:terrence]]

Comment on attachment 8584185 [details] [diff] [review]
Replace manual AllocKind range checks with a few centralized functions.

Review of attachment 8584185 [details] [diff] [review]:
-----------------------------------------------------------------

Very nice!

Comment 5

[Emanuel Hoogeveen [:ehoogeveen]]

Attachment: v1.1 - Replace manual AllocKind range checks with a few centralized functions.

Carrying forward r=terrence. The mass SM restyle meant this needed some rebasing.

Comment 6

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 8584185 [details] [diff] [review]
Replace manual AllocKind range checks with a few centralized functions.

The SM restyle got backed out.

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/db80ac5a48aa

Comment 8

[Emanuel Hoogeveen [:ehoogeveen]]

Thanks for landing the right one for me, Ryan!

Comment 9

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/db80ac5a48aa