1724236 - Use JS::Stencil directly in dom::ScriptLoader

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task, P2)

Description

[Ted Campbell [:tcampbell]]

Now that Stencil is core to all our parsing and caching flows for JS, we should directly use the JS::Stencil type from the dom::ScriptLoader and explicitly calling instantiate. This will allow us to build in-memory caches around JS::Stencil to improve our caching story.

Comment 1

[Ted Campbell [:tcampbell]]

It might be necessary to fix Bug 1687973 so that this proposed change can also cover the decode case. Even without that, it is still possible to support to do in-memory caching with just the non-decode path.

Comment 2

[Bryan Thrall [:bthrall]]

No one is actively working on this, so it is unlikely to land before the next release.

Comment 3

[Bryan Thrall [:bthrall]]

According to :arai:

we'll need to introduce some structure to hold the delazification result. it may be hidden behind current Stencil struct, or maybe exposed as separate struct. if latter, it may be owned by embedding side, and then removing the indirection from JSExecutionContext beforehand would work nicely

Comment 4

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move error tracking to JSExecutionContext callers r=arai!

Comment 5

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Get CompileOptions from function arguments instead of member r=arai!

Comment 6

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Get encodeBytecode and coerceToString from function arguments instead of members r=arai!

Comment 7

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move profiler label and JSAutoRealm out of JSExecutionContext r=arai!

Comment 8

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Check options directly if script wants return value r=arai!

Comment 9

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Pass script as function argument instead of member r=arai!

Comment 10

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Pass cx as function argument instead of member r=arai!

Comment 11

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move ExecScript out of JSExecutionContext r=arai!

Comment 12

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move InstantiateStencil out of Compile and Decode r=arai!

Comment 13

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move Compile and Decode out of JSExecutionContext r=arai!

Comment 14

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Inline ExecScript and move ExecScriptAndCoerceString to where it is used r=arai!

ExecScript returning a value was only used in one place, and that call always
coerced the return value to a string.

Comment 15

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Inline Compile(JS::SourceText) r=arai!

The remaining Compile(nsAString) could be inlined as well, but it is only used
in nsJSThunk::EvaluateScript and WindowScriptTimeoutHandler::Call. Right now,
I'm just focusing on use by ScriptLoader.

Comment 16

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move Decode to ScriptLoader r=arai!

ScriptLoader is the only place that calls it, and inlining it made the call
site too hard to follow.

Comment 17

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Pass debugger parameters as arguments instead of members r=arai!

Comment 18

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move JoinOffThread and InstantiateStencil out of JSExecutionContext r=arai!

Comment 19

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Inline JoinOffThread r=arai!

Comment 20

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Remove JSExecutionContext r=arai!

I think the constructor assertions don't need to be preserved, since the
locations where JSExecutionContext was constructed are obviously using a real
global on the main thread. I'm less confident in removing the check for
CycleCollectedJSContext::Get()->MicroTaskLevel(), but it should be ok since the
assertion wasn't failing already.

I'm leaving the profiler label "JSExecutionContext" intact for now so there's
no change in recorded profiles, but we should consider a better name for it in
the future.

Comment 21

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Rename JSExecutionUtils from JSExecutionContext r=arai!

Comment 22

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Inline InstantiateStencil(cx, options, stencil, script) r=arai!

Comment 23

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move InstantiateStencil() to ScriptLoader r=arai!

Comment 24

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move stencil duplication out of JoinOffThread, Decode, Compile r=arai!

Comment 25

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Simplify error handling via ErrorResult r=arai!

Comment 26

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Move InstantiateStencil call out of JoinOffThread r=arai!

Comment 27

[Bryan Thrall [:bthrall]]

Attachment: Bug 1724236 - Perform early return on permission check r=arai!

Comment 28

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/5f393558af46
Move error tracking to JSExecutionContext callers r=arai
https://hg.mozilla.org/integration/autoland/rev/6b848af68b04
Simplify error handling via ErrorResult r=arai
https://hg.mozilla.org/integration/autoland/rev/e639f1a9629f
Get CompileOptions from function arguments instead of member r=arai
https://hg.mozilla.org/integration/autoland/rev/1a3d0a484cc7
Get encodeBytecode and coerceToString from function arguments instead of members r=arai
https://hg.mozilla.org/integration/autoland/rev/a9662e54468c
Move profiler label and JSAutoRealm out of JSExecutionContext r=arai
https://hg.mozilla.org/integration/autoland/rev/a5c8b186811b
Check options directly if script wants return value r=arai
https://hg.mozilla.org/integration/autoland/rev/f74774467596
Pass script as function argument instead of member r=arai
https://hg.mozilla.org/integration/autoland/rev/617a207931b0
Pass cx as function argument instead of member r=arai
https://hg.mozilla.org/integration/autoland/rev/cc1882488435
Move ExecScript out of JSExecutionContext r=arai
https://hg.mozilla.org/integration/autoland/rev/7b334fe58713
Move InstantiateStencil out of Compile and Decode r=arai
https://hg.mozilla.org/integration/autoland/rev/71cceb0503ab
Move InstantiateStencil call out of JoinOffThread r=arai
https://hg.mozilla.org/integration/autoland/rev/6d67fc5a1f35
Move stencil duplication out of JoinOffThread, Decode, Compile r=arai
https://hg.mozilla.org/integration/autoland/rev/4ca74ab38fb2
Move Compile and Decode out of JSExecutionContext r=arai
https://hg.mozilla.org/integration/autoland/rev/0e62b884ada0
Inline ExecScript and move ExecScriptAndCoerceString to where it is used r=arai
https://hg.mozilla.org/integration/autoland/rev/fea0294e3205
Inline Compile(JS::SourceText) r=arai
https://hg.mozilla.org/integration/autoland/rev/62b9acbd2a69
Move Decode to ScriptLoader r=arai
https://hg.mozilla.org/integration/autoland/rev/a951b39e3346
Pass debugger parameters as arguments instead of members r=arai
https://hg.mozilla.org/integration/autoland/rev/0233a41b9f9c
Move JoinOffThread and InstantiateStencil out of JSExecutionContext r=arai
https://hg.mozilla.org/integration/autoland/rev/fecec3d85af1
Inline JoinOffThread r=arai
https://hg.mozilla.org/integration/autoland/rev/f966c15bbee6
Remove JSExecutionContext r=arai
https://hg.mozilla.org/integration/autoland/rev/542fd2b11f0b
Rename JSExecutionUtils from JSExecutionContext r=arai
https://hg.mozilla.org/integration/autoland/rev/9bbb86e07d45
Inline InstantiateStencil(cx, options, stencil, script) r=arai
https://hg.mozilla.org/integration/autoland/rev/75093f3e947c
Move InstantiateStencil() to ScriptLoader r=arai
https://hg.mozilla.org/integration/autoland/rev/ce9f60c59095
Perform early return on permission check r=arai

Comment 29

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/5f393558af46
https://hg.mozilla.org/mozilla-central/rev/6b848af68b04
https://hg.mozilla.org/mozilla-central/rev/e639f1a9629f
https://hg.mozilla.org/mozilla-central/rev/1a3d0a484cc7
https://hg.mozilla.org/mozilla-central/rev/a9662e54468c
https://hg.mozilla.org/mozilla-central/rev/a5c8b186811b
https://hg.mozilla.org/mozilla-central/rev/f74774467596
https://hg.mozilla.org/mozilla-central/rev/617a207931b0
https://hg.mozilla.org/mozilla-central/rev/cc1882488435
https://hg.mozilla.org/mozilla-central/rev/7b334fe58713
https://hg.mozilla.org/mozilla-central/rev/71cceb0503ab
https://hg.mozilla.org/mozilla-central/rev/6d67fc5a1f35
https://hg.mozilla.org/mozilla-central/rev/4ca74ab38fb2
https://hg.mozilla.org/mozilla-central/rev/0e62b884ada0
https://hg.mozilla.org/mozilla-central/rev/fea0294e3205
https://hg.mozilla.org/mozilla-central/rev/62b9acbd2a69
https://hg.mozilla.org/mozilla-central/rev/a951b39e3346
https://hg.mozilla.org/mozilla-central/rev/0233a41b9f9c
https://hg.mozilla.org/mozilla-central/rev/fecec3d85af1
https://hg.mozilla.org/mozilla-central/rev/f966c15bbee6
https://hg.mozilla.org/mozilla-central/rev/542fd2b11f0b
https://hg.mozilla.org/mozilla-central/rev/9bbb86e07d45
https://hg.mozilla.org/mozilla-central/rev/75093f3e947c
https://hg.mozilla.org/mozilla-central/rev/ce9f60c59095