Bug 166458 – Looking up properties on ModuleNamespaceObject is slow

• Status: RESOLVED
• Resolution: DUPLICATE
• Component: JavaScriptCore

[Saam Barati]

Consider these two programs:

a:
```
import * as assert from "../assert.js";

let array = [];
for (let i = 0; i < 40000000; i++) {
    array.push(i);
}

for (let i = 0; i < 40000000; i++) {
    assert.eq(array[i], i);
}
```

b:
```
import {eq} from "../assert.js";


let array = [];
for (let i = 0; i < 40000000; i++) {
    array.push(i);
}

for (let i = 0; i < 40000000; i++) {
    eq(array[i], i);
}
```

Program "b" is more than 4x faster than program "a".

[Yusuke Suzuki]

https://bugs.webkit.org/show_bug.cgi?id=160590 this one?
Currently I think we can convert this access to CheckCell, GetClosureVar in DFG.

[Saam Barati]

(In reply to comment #1)
> https://bugs.webkit.org/show_bug.cgi?id=160590 this one?
> Currently I think we can convert this access to CheckCell, GetClosureVar in
> DFG.

Yeah, this is a dupe.

*** This bug has been marked as a duplicate of bug 160590 ***