commit 69985ac52734c807456157c59ead62438b558f2c
author Benedikt Meurer <bmeurer@chromium.org> Thu Aug 23 10:55:40 2018
committer Commit Bot <commit-bot@chromium.org> Thu Aug 23 11:36:17 2018
tree 7b5bf1478f50709e97bc646fb15e038e6da1cb38
parent 28afdca68349b3ae7584732ba4eea0743b33d794

[turbofan] Optimize index checking for DataView accesses.

Use CheckBounds and reduce the number of checks required to sanitize the
indices for DataView accesses in optimized code. Also constant-fold the
[[ByteLength]] if the DataView is a known compile-time constant (similar
to what we do for TypedArrays already). This further improves performance
of DataViews by 2-7% depending on the exact test case.

With this change DataView and TypedArray accesses themselves are mostly
on par performance wise.

Since this CL introduces proper CheckBounds for the DataViews, instead
of the hand-craftet bounds checks, it is expected to regress performance
when untrusted code mitigations are on, since DataViews are also guarded
in optimized now. Without untrusted code mitigations, there's no negative
performance impact.

Tbr: sigurds@chromium.org
Bug: chromium:225811, chromium:876005
Change-Id: I4a69f81124635c9ba2c7e4c2dc912e2fd601061a
Reviewed-on: https://chromium-review.googlesource.com/1186408
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55346}