commit 426ae4265e539da2932ea2cb2cc1aeed97788b41
author Benedikt Meurer <bmeurer@chromium.org> Thu Aug 03 05:20:48 2017
committer Commit Bot <commit-bot@chromium.org> Thu Aug 03 06:13:13 2017
tree 26bde373dd3a064b1710c12e16ec8fbe8d617ba1
parent b27bd825f3145cdc668aa38274c6d17e6bc46273

[csa] Extend TryToName to also implicitly convert Oddball keys.

Previously TryToName bailed out for Oddball keys (i.e. when passing true
or false as the key), which meant that for example the generic
KeyedLoadIC would always bail out to the %KeyedGetProperty runtime
function. But handling Oddball keys is fairly easy, since every oddball
value carries it's unique string representation. Adding just this case
to the CodeStubAssembler::TryToName method boosts this simple
micro-benchmark by a factor of 4x:

  const n = 1e7;
  const obj = {};
  const key = true;

  console.time('foo');
  for (let i = 0; i < n; ++i) {
    if (obj[key] === undefined) {
      obj[key] = key;
    }
  }
  console.timeEnd('foo');

It also shows on the ARES-6 ML benchmark and on several Speedometer
tests, where objects are being used as dictionaries and the developers
rely on the implicit ToString conversions on the property accesses.
In the ARES-6 ML benchmark, the number of calls to %KeyedGetProperty
is reduced by 137,758.

Bug: v8:6278, v8:6344, v8:6670
Change-Id: Iaa965e30be4c247682a67ec09543655df9b761d2
Reviewed-on: https://chromium-review.googlesource.com/599527
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47105}