1784023 - Inline String.prototype.endsWith with constant search strings

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, enhancement)

Description

[André Bargull [:anba]]

Like bug 1782959, except for endsWith instead of startsWith.

Real world use case:
This saves a couple of thousand VM calls to endsWith per second when watching videos on reddit.

---

Additionally also fold str.indexOf(searchStr) == 0 to str.startsWith(searchStr), because I saw some sites benefiting from this optimisation.

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1784023 - Part 1: Add comma after JS_FS_END for nicer formatting. r=jandem!

Adding a comma after JS_FS_END ensures clang-format will add each entry on a
separate line.

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1784023 - Part 2: Inline String.prototype.endsWith. r=jandem!

For now simply call into the VM. Part 3 will add an optimisation when the
search string is a constant.

Depends on D154210

Comment 3

[André Bargull [:anba]]

Attachment: Bug 1784023 - Part 3: Inline String.prototype.endsWith with a constant search string. r=jandem!

This is similar to the optimisation for String.prototype.startsWith.

Depends on D154211

Comment 4

[André Bargull [:anba]]

Attachment: Bug 1784023 - Part 4: Inline String.prototype.indexOf() with a VM-call. r=jandem!

The next part will try to optimise indexOf() when it can be folded to
startsWith().

Depends on D154212

Comment 5

[André Bargull [:anba]]

Attachment: Bug 1784023 - Part 5: Fold MStringIndexOf to MStringStartsWith. r=jandem!

Depends on D154213

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c4538d007f20
Part 1: Add comma after JS_FS_END for nicer formatting. r=jandem
https://hg.mozilla.org/integration/autoland/rev/c28f80a3d291
Part 2: Inline String.prototype.endsWith. r=jandem
https://hg.mozilla.org/integration/autoland/rev/22bd3cd5785d
Part 3: Inline String.prototype.endsWith with a constant search string. r=jandem
https://hg.mozilla.org/integration/autoland/rev/242adcdcf927
Part 4: Inline String.prototype.indexOf() with a VM-call. r=jandem
https://hg.mozilla.org/integration/autoland/rev/53f620bb8261
Part 5: Fold MStringIndexOf to MStringStartsWith. r=jandem

Comment 7

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/c4538d007f20
https://hg.mozilla.org/mozilla-central/rev/c28f80a3d291
https://hg.mozilla.org/mozilla-central/rev/22bd3cd5785d
https://hg.mozilla.org/mozilla-central/rev/242adcdcf927
https://hg.mozilla.org/mozilla-central/rev/53f620bb8261