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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [[Set]] should be properly executed in JS builtins"
href="https://bugs.webkit.org/show_bug.cgi?id=143996">143996</a>
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<th>Summary</th>
<td>[[Set]] should be properly executed in JS builtins
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<th>Classification</th>
<td>Unclassified
</td>
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<th>Product</th>
<td>WebKit
</td>
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<th>Version</th>
<td>528+ (Nightly build)
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<th>Hardware</th>
<td>Unspecified
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<th>OS</th>
<td>Unspecified
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>Normal
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<th>Priority</th>
<td>P2
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<th>Component</th>
<td>JavaScriptCore
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<th>Assignee</th>
<td>webkit-unassigned@lists.webkit.org
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<th>Reporter</th>
<td>utatane.tea@gmail.com
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<pre>Currently, all assignments in builtins JS code is compiled into put_by_val_direct.
However, some functions (like Array.from) needs [[Set]]. (but it is now compiled into pu_by_val_direct, [[DefineOwnProperty]]).
By leveraging bytecode intrinsics, we'll fix it.
There's 2 plans to solve this.
1. Implement the bytecode intrinsic for [[DefineOwnProperty]] and remove the hack for builtins
Currently, assignments in builtins JS code are compiled into put_by_val_direct.
However, it's different from the default JS behavior.
In this plan, we implement the bytecode intrinsic emitting put_by_val_direct and use it explicitly.
And dropping the current hack for builtins.
2. Implement the bytecode intrinsic for [[Set]] and keep the current hack for builtins
However, a lot of builtins code requires [[DefineOwnProperty]] behavior rather than [[Set]].
So keeping the current hack for builtins. By default, assignments in builtins are compiled into put_by_val_direct.
And implementing the bytecode intrinsic emitting put_by_val ([[Set]])</pre>
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