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  1. 13 Jul, 2018 1 commit
  3. 12 Jul, 2018 1 commit
    • Leszek Swirski's avatar
      [cleanup] Remove Isolate parameter from object print · 13b899a5
      Leszek Swirski authored 
      With ReadOnlyRoots and GetIsolate on JSReceiver, we can remove almost
every isolate parameter from <Object>::Print. The remaining ones, like
Map, are special-caseable for read-only maps, and as a result we can
remove isolate parameters from <Object>::Print entirely.

This patch also opportunistically cleans up a few places where isolates
were only needed for Object::Print, such as TransitionAccessors and
DescriptorArrays.

TBR=yangguo@chromium.org,mstarzinger@chromium.org

Bug: v8:7786
Change-Id: Id44bd53b9893e679eea5f37b9548257595a1bfd9
Reviewed-on: https://chromium-review.googlesource.com/1133385Reviewed-by: 's avatarLeszek Swirski <leszeks@chromium.org>
Reviewed-by: 's avatarDan Elphick <delphick@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54401}
      13b899a5
  5. 26 Jun, 2018 1 commit
  7. 21 Jun, 2018 1 commit
  9. 09 Apr, 2018 1 commit
  11. 22 Feb, 2018 1 commit
  13. 28 Nov, 2017 1 commit
  15. 24 Oct, 2017 1 commit
  17. 01 Aug, 2017 1 commit
    • Benedikt Meurer's avatar
      [builtins] Speed-up Object.prototype.toString. · 31800120
      Benedikt Meurer authored 
      The @@toStringTag lookup in Object.prototype.toString causes quite a
lot of overhead and oftentimes dominates the builtin performance. These
lookups are almost always negative, especially for primitive values,
and Object.prototype.toString is often used to implement predicates
(like in Node core or in AngularJS), so having a way to skip the
negative lookup yields big performance gains.

This CL introduces a "MayHaveInterestingSymbols" bit on every map,
which says whether instances with this map may have an interesting
symbol. Currently only @@toStringTag is considered an interesting
symbol, but we can extend that in the future.

In the Object.prototype.toString we can use the interesting symbols
bit to do a quick check on the prototype chain to see if there are
any maps that might have the @@toStringTag, and if not, we can just
immediately return the result, which is very fast because it's derived
from the instance type. This also avoids the ToObject conversions for
primitive values, which is important, since this causes unnecessary
GC traffic and in for example AngularJS, strings are also often probed
via the Object.prototype.toString based predicates.

This boosts Speedometer/AngularJS by over 3% and Speedometer overall
by up to 1%. On the microbenchmark from the similar SpiderMonkey bug
(https://bugzilla.mozilla.org/show_bug.cgi?id=1369042), we go from
roughly 450ms to 70ms, which corresponds to a 6.5x improvement.

```
function f() {
    var res = "";
    var a = [1, 2, 3];
    var toString = Object.prototype.toString;
    var t = new Date;
    for (var i = 0; i < 5000000; i++)
	res = toString.call(a);
    print(new Date - t);
    return res;
}
f();
```

The design document at https://goo.gl/e8CruQ has some additional
data points.

TBR=ulan@chromium.org

Bug: v8:6654
Change-Id: I31932cf41ecddad079d294e2c322a852af0ed244
Reviewed-on: https://chromium-review.googlesource.com/593620
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: 's avatarCamillo Bruni <cbruni@chromium.org>
Reviewed-by: 's avatarJaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47034}
      31800120
  19. 13 Jul, 2017 1 commit
  21. 29 Jun, 2017 1 commit
  23. 16 Jun, 2017 1 commit
  25. 14 Jun, 2017 1 commit
  27. 12 Jun, 2017 1 commit