<html>
    <head>
      <base href="https://bugs.webkit.org/">
    </head>
    <body>
      <p>
        <div>
            <b><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Enable IC for put_by_id_with_this"
   href="https://bugs.webkit.org/show_bug.cgi?id=162125#c15">Comment # 15</a>
              on <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Enable IC for put_by_id_with_this"
   href="https://bugs.webkit.org/show_bug.cgi?id=162125">bug 162125</a>
              from <span class="vcard"><a class="email" href="mailto:ticaiolima&#64;gmail.com" title="Caio Lima &lt;ticaiolima&#64;gmail.com&gt;"> <span class="fn">Caio Lima</span></a>
</span></b>
        <pre>Comment on <span class=""><a href="attachment.cgi?id=305938&amp;action=diff" name="attach_305938" title="Proposed Patch">attachment 305938</a> <a href="attachment.cgi?id=305938&amp;action=edit" title="Proposed Patch">[details]</a></span>
Proposed Patch

View in context: <a href="https://bugs.webkit.org/attachment.cgi?id=305938&amp;action=review">https://bugs.webkit.org/attachment.cgi?id=305938&amp;action=review</a>

<span class="quote">&gt;&gt; Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp:4591
&gt;&gt; +        notCellList.append(m_jit.branchIfNotCell(JSValueRegs(thisGPR)));
&gt; 
&gt; Looks like a bug that you don't use this after appending to it. Please add tests. Should be an Insta crash.
&gt; 
&gt; That said, the more I think about it, are there any scenarios where |this|/base won't be a cell?</span >

Oops. It should be a cachedPutByIdWithThis parameter. However, I'm following your thinking too. __proto__ can be &quot;null&quot; or  &quot;object&quot;. When it is null, ```super.something``` will fail as TypeError. (<a href="https://tc39.github.io/ecma262/#sec-set-object.prototype.__proto__">https://tc39.github.io/ecma262/#sec-set-object.prototype.__proto__</a>). If I'm not missing something, either base/this are always Cell.

<span class="quote">&gt;&gt; Source/JavaScriptCore/jit/Repatch.cpp:353
&gt;&gt; +        if (UNLIKELY(putKind == WithThis))
&gt; 
&gt; I don't think you need the UNLIKELY here. It might be the case that users do use this a lot.</span >

Done.

<span class="quote">&gt; Source/JavaScriptCore/runtime/JSObjectInlines.h:205
&gt; +    if (UNLIKELY(isThisValueAltered(slot, thisObject) &amp;&amp; slot.context() != PutPropertySlot::PutByIdWithThis))</span >

Just got a case where this condition is not ok. Investigating a properly way to set slot properly here.</pre>
        </div>
      </p>


      <hr>
      <span>You are receiving this mail because:</span>

      <ul>
          <li>You are the assignee for the bug.</li>
      </ul>
    </body>
</html>