1435222 - LLambdaArrow could request a temp-register instead of reusing the ValueOperand's scratch-register

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, enhancement, P3)

Description

[André Bargull [:anba]]

https://searchfox.org/mozilla-central/rev/eeb7190f9ad6f1a846cd6df09986325b3f2c3117/js/src/jit/CodeGenerator.cpp#2783-2785:
---
    // There's not enough registers on x86 with the profiler enabled to request
    // a temp. Instead, spill part of one of the values, being prepared to
    // restore it if necessary on the out of line path.
---

I don't think that's true anymore since bug 1132183. So if we want to, we probably could add a temp-register for LLambdaArrow.

Comment 1

[André Bargull [:anba]]

Taking so I can piggyback two other clean-ups without having to open new bugs.

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1435222 - Part 1: Use temp register for LLambdaArrow. r=jandem!

Comment 3

[André Bargull [:anba]]

Attachment: Bug 1435222 - Part 2: Use boxAtStart for LComputeThis. r=jandem!

Bug 941617 changed LComputeThis to not use boxAtStart because of backtracking
allocator assertions (see also bug 936891). These assertions were relaxed in
bug 968931, so we can now use boxAtStart again. There are even other
operations which work similarly and use boxAtStart, like for example
LToNumeric, which also demonstrates that it's now okay to use boxAtStart.

Depends on D56372

Comment 4

[André Bargull [:anba]]

Attachment: Bug 1435222 - Part 3: Remove unused modifiesFrameArguments_ flag. r=jandem!

This flag was used for the linear scan register allocator.

Depends on D56373

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/bc7562ddd7ce
Part 1: Use temp register for LLambdaArrow. r=jandem
https://hg.mozilla.org/integration/autoland/rev/9cdca7c93123
Part 2: Use boxAtStart for LComputeThis. r=jandem
https://hg.mozilla.org/integration/autoland/rev/60a806a049ca
Part 3: Remove unused modifiesFrameArguments_ flag. r=jandem

Comment 6

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/bc7562ddd7ce
https://hg.mozilla.org/mozilla-central/rev/9cdca7c93123
https://hg.mozilla.org/mozilla-central/rev/60a806a049ca