1356665 - Method calls take a slow path in the interpreter

Status: NEW

(Core :: JavaScript Engine, enhancement, P3)

Description

[Jason Orendorff [:jorendorff]]

There's a fast path for JSOP_CALL when we're calling a scripted function. But it doesn't hit for functions that are defined as ES6+ methods:

    let obj = {
      method() {}
    };

    obj.method();   // slow path when in interpreter

Note the comment in the interpreter:

    /* Don't bother trying to fast-path calls to scripted non-constructors. */
    if (!isFunction || !maybeFun->isInterpreted() || !maybeFun->isConstructor() ||
        (!construct && maybeFun->isClassConstructor()))
    {
        (...slow path...)
    }

The third test, maybeFun->isConstructor(), is the one that fails.