This addresses the odd performance cliff, where the CallIC tracks known
JSFunction targets, but goes MEGAMORPHIC when it sees a JSBoundFunction
target. With this fix in place the micro-benchmark on the bug goes from
arrowCall: 82 ms.
boundCall: 234 ms.
to
arrowCall: 81 ms.
boundCall: 80 ms.
so Function#bind doesn't cause any additional overhead anymore.
Bug: v8:5267, v8:6962
Change-Id: Iaceaf89fd3e99e2afe2ae45e96a6813a3ef8b1d2
Reviewed-on: https://chromium-review.googlesource.com/727879
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48722}
So far the JSCallReducer was only able to unfold constant
JSBoundFunction targets for JSCall nodes, which is not the
common case. With the introduction of JSCreateBoundFunction
operator earlier, we can now also recognize calls to bound
functions where the bind happens earlier in the function,
i.e. as the example of
a.map(f.bind(self))
in https://twitter.com/BenLesh/status/920700003974123520, which
is a handy way to use Function#bind. So this transformation
takes a node like
JSCall(JSCreateBoundFunction(bound_target_function,
bound_this,
a1,...,aN),
receiver, p1,...,pM)
and turns that into
JSCall(bound_target_function, bound_this, a1,...,aN,p1,...,pM)
allowing TurboFan to further inline the bound_target_function
at this call site if that's also inlinable (i.e. it's a known
constant JSFunction or the result of a JSCreateClosure call).
This improves the micro-benchmark from
arrowCall: 55 ms.
boundCall: 221 ms.
arrowMap: 181 ms.
boundMap: 806 ms.
to
arrowCall: 71 ms.
boundCall: 76 ms.
arrowMap: 188 ms.
boundMap: 186 ms.
so that Function#bind in this case is as fast as using closures,
which is an up to 4.3x improvement in the Array#map example.
Bug: v8:5257, v8:6961
Change-Id: Ibca650faad912bf9db1db6fbc48772e7551289a6
Reviewed-on: https://chromium-review.googlesource.com/727799
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48713}
When the input to Function.prototype.bind is a known function, we can
inline the allocation of the JSBoundFunction into TurboFan, which
provides a 2x speed-up for several hot functions in Node streams (as
discovered by Matteo Collina). One of example of this can be found in
https://github.com/nodejs/node/pull/13322, which can be optimized and
made more readable using bind instead of closures.
R=jarin@chromium.org
Review-Url: https://codereview.chromium.org/2916063002
Cr-Commit-Position: refs/heads/master@{#45679}
