1627111 - Support relazifying async/generator functions

Status: REOPENED

(Core :: JavaScript Engine, task, P3)

Description

[Ted Campbell [:tcampbell]]

Thanks to the BaseScript and BaselineInterpreter projects it should be feasible to support relazifying async and generator functions.

A few places need to replace JSFunction::nonLazyScript() calls with JSFunction::getOrCreateScript(). We already check for a JitScript before using the Baseline resume-entrypoints which simplifies things.

Comment 1

[Ted Campbell [:tcampbell]]

Attachment: Bug 1627111 - Store the opcode that caused a generator to pause. r?jandem!

This allows the AsyncGeneratorResume logic to determine how to resume without
needing access to the full bytecode.

Comment 2

[Ted Campbell [:tcampbell]]

Attachment: Bug 1627111 - Allow relazifying generators. r?jandem!

Add a few uses of JSFunction::getOrCreateScript to tolerate lazy generators
in the resume code. We then remove the relazification restrictions.

Depends on D69458

Comment 3

[Ted Campbell [:tcampbell]]

Here is a prototype of it. I need a big more targeted testing for correctness and validation of performance. One nice aspect of the new BaseScript design, is that mistakes here will only result in nullptr crashes by trying to access bytecode on a lazy script.

Comment 4

[Ted Campbell [:tcampbell]]

This prototype is still pretty broken in a few cases.

Comment 5

[Ted Campbell [:tcampbell]]

Attachment: Bug 1627111 - Make DebuggerFrame::setGeneratorInfo static. r?jandem!

In later patches, this may GC and this may be moved.

Depends on D69458

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8d0cb8c6bb7c
Store the opcode that caused a generator to pause. r=jandem
https://hg.mozilla.org/integration/autoland/rev/5ff84c1e2f55
Make DebuggerFrame::setGeneratorInfo static. r=jandem
https://hg.mozilla.org/integration/autoland/rev/28e150b3df59
Allow relazifying generators. r=jandem

Comment 7

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/8d0cb8c6bb7c
https://hg.mozilla.org/mozilla-central/rev/5ff84c1e2f55
https://hg.mozilla.org/mozilla-central/rev/28e150b3df59

Comment 8

[Atila Butkovits]

Backed out as requested by Ted.

Backout link: https://hg.mozilla.org/integration/autoland/rev/751ecfca72b1fd7e210cfa845e008e6e5d9ca107

Comment 9

[Andra Esanu (needinfo me)]

== Change summary for alert #28570 (as of Mon, 01 Feb 2021 11:31:22 GMT) ==

Improvements:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
1%	Base Content JS		windows10-64-shippable		2,511,200.00 -> 2,497,386.67
1%	Base Content JS		windows10-64-shippable-qr		2,511,197.33 -> 2,497,349.33
1%	Base Content JS		windows10-64-shippable-qr		2,511,200.00 -> 2,497,381.33
1%	Base Content JS		linux1804-64-shippable		2,506,725.33 -> 2,493,149.33
1%	Base Content JS		linux1804-64-shippable-qr		2,506,064.00 -> 2,493,257.33
0.45%	Base Content JS		macosx1014-64-shippable-qr		2,509,365.33 -> 2,498,001.33

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=28570

Comment 10

[Andra Esanu (needinfo me)]

== Change summary for alert #28601 (as of Wed, 03 Feb 2021 10:47:34 GMT) ==

Regressions:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
1%	Base Content JS		macosx1014-64-shippable-qr		2,498,901.33 -> 2,512,853.33
1%	Base Content JS		linux1804-64-shippable		2,492,894.00 -> 2,506,218.67
1%	Base Content JS		windows10-64-shippable		2,497,268.00 -> 2,510,589.33
1%	Base Content JS		windows10-64-shippable-qr		2,497,264.67 -> 2,510,576.00
1%	Base Content JS		windows10-64-shippable-qr		2,497,262.67 -> 2,510,584.00
1%	Base Content JS		linux1804-64-shippable-qr		2,493,860.67 -> 2,506,906.67

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=28601

Comment 11

[Ted Campbell [:tcampbell]]

The patches I had here were not sound. It may be possible to fix still, but it is not a priority