1934972 - Try to remove CodeGenerator::zoneStubsToReadBarrier_

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task)

Description

[Jan de Mooij [:jandem]]

zoneStubsToReadBarrier_ is used to perform read-barriers after off-thread compilation for the per-zone regexp/string stubs used by the compilation. It's hard to reason about how this interacts with major GCs happening on the main thread if these GCs don't cancel off-thread compilations.

It would be simpler to get these stubs at the start of the compilation so we can store strong references to them in the Warp snapshot.

Comment 1

[Jan de Mooij [:jandem]]

Attachment: Bug 1934972 part 1 - Tidy up JitZone stubs a bit. r?iain!

Rename StubIndex to StubKind and make it an enum class.

Add a using declaration for the EnumeratedArray. This will be used more in a
later patch.

Comment 2

[Jan de Mooij [:jandem]]

Attachment: Bug 1934972 part 2 - Pass the WarpSnapshot to CodeGenerator. r?iain!

Comment 3

[Jan de Mooij [:jandem]]

Attachment: Bug 1934972 part 3 - Store used JitZone stubs in WarpSnapshot, remove zoneStubsToReadBarrier_. r?iain!,jonco!

zoneStubsToReadBarrier_ was used to delay read-barriers for the JitZone stubs
for off-thread Ion compilations. This only works well if we cancel Ion compilations
on GC.

This patch changes this to instead record used stubs in the Warp snapshot that we trace
for off-thread compilations.

We also no longer generate the string-concat stub eagerly but only if the CacheIR has
a string-concat op.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/58902759f620
part 1 - Tidy up JitZone stubs a bit. r=iain
https://hg.mozilla.org/integration/autoland/rev/4810dda31f44
part 2 - Pass the WarpSnapshot to CodeGenerator. r=iain
https://hg.mozilla.org/integration/autoland/rev/af214c46fc64
part 3 - Store used JitZone stubs in WarpSnapshot, remove zoneStubsToReadBarrier_. r=iain,jonco

Comment 5

[Cristian Tuns]

https://hg.mozilla.org/mozilla-central/rev/58902759f620
https://hg.mozilla.org/mozilla-central/rev/4810dda31f44
https://hg.mozilla.org/mozilla-central/rev/af214c46fc64

Comment 6

[Mayank Bansal]

tiny regression:

5% on kraken-imaging-gaussian-blur only on Windows.