1917516 - Improve generated code for PropertyKey::isAtom

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task)

Description

[André Bargull [:anba]]

We use both JS::PropertyKey::isAtom(JSAtom*) and NameToId(PropertyName*) == to compare property names against property key, but the latter actually produces better codegen. Change JS::PropertyKey::isAtom(JSAtom*) to allow producing the same assembly when compared to using NameToId.

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1917516 - Part 1: Allow better code generation for PropertyKey::isAtom. r=#spidermonkey-reviewers!

Improves the generated code from:

xor     rsi, rdi
and     edi, 7
or      rsi, rdi
sete    al

to:

cmp     rsi, rdi
sete    al

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1917516 - Part 2: Prefer NameToId over PropertyKey::NonIntAtom. r=#spidermonkey-reviewers!

Prefer NameToId per doc-comments for PropertyKey::NonIntAtom.

Drive-by change:

• Remove unnecessary rooting in AddPrefix.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6e24c99504f6
Part 1: Allow better code generation for PropertyKey::isAtom. r=spidermonkey-reviewers,jandem
https://hg.mozilla.org/integration/autoland/rev/07da26c7d185
Part 2: Prefer NameToId over PropertyKey::NonIntAtom. r=spidermonkey-reviewers,jandem

Comment 4

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/6e24c99504f6
https://hg.mozilla.org/mozilla-central/rev/07da26c7d185