Improve performance of ClassMirror.newInstance.

Improve performance of ClassMirror.newInstance.

R=ngeoffray@google.com

Committed: https://code.google.com/p/dart/source/detail?r=26065

[ahe, 2013-08-12 23:12:29]

Benchmark results (smaller is better).

Before:

Runtime: 147ms
Runtime: 98ms
Runtime: 164ms
Runtime: 168ms

After:

Runtime: 43ms
Runtime: 26ms
Runtime: 50ms
Runtime: 42ms

Benchmark source:

library foo;

@MirrorsUsed(targets: 'Foo', override: '*')
import 'dart:mirrors';

import 'dart:isolate';

class Foo {
  m() => 1;
}

void isolate() {
  ClassMirror m = reflectClass(Foo);
  Stopwatch sw = new Stopwatch()..start();
  for (int i = 0; i < 100000; i++) {
    if (m.newInstance(const Symbol(''), []).reflectee.m() != 1) throw 'Bad
mirror';
  }
  sw.stop();
  print('Runtime: ${sw.elapsedMilliseconds}ms');
}

main() {
  isolate();
  isolate();
  spawnFunction(isolate);
  spawnFunction(isolate);
}

[ngeoffray, 2013-08-13 13:03:32]

LGTM

https://codereview.chromium.org/22934004/diff/4001/dart/sdk/lib/_internal/lib...
File dart/sdk/lib/_internal/lib/js_helper.dart (right):

https://codereview.chromium.org/22934004/diff/4001/dart/sdk/lib/_internal/lib...
dart/sdk/lib/_internal/lib/js_helper.dart:665: JS('void', 'delete #.x', result);
Please add a comment on why you want to delete.

https://codereview.chromium.org/22934004/diff/4001/dart/sdk/lib/_internal/lib...
File dart/sdk/lib/_internal/lib/js_mirrors.dart (right):

https://codereview.chromium.org/22934004/diff/4001/dart/sdk/lib/_internal/lib...
dart/sdk/lib/_internal/lib/js_mirrors.dart:772: 'JsMethodMirror|Null', '#[#]',
_jsConstructorCache, n(constructorName));
How about adding a class for a js cache that just holds static functions, and
would do a 'allocate', 'fetch', 'update'.

[ahe, 2013-08-13 17:04:41]

Thank you, Nicolas!

https://codereview.chromium.org/22934004/diff/4001/dart/sdk/lib/_internal/lib...
File dart/sdk/lib/_internal/lib/js_helper.dart (right):

https://codereview.chromium.org/22934004/diff/4001/dart/sdk/lib/_internal/lib...
dart/sdk/lib/_internal/lib/js_helper.dart:665: JS('void', 'delete #.x', result);
On 2013/08/13 13:03:32, ngeoffray wrote:
> Please add a comment on why you want to delete.

Done.

https://codereview.chromium.org/22934004/diff/4001/dart/sdk/lib/_internal/lib...
File dart/sdk/lib/_internal/lib/js_mirrors.dart (right):

https://codereview.chromium.org/22934004/diff/4001/dart/sdk/lib/_internal/lib...
dart/sdk/lib/_internal/lib/js_mirrors.dart:772: 'JsMethodMirror|Null', '#[#]',
_jsConstructorCache, n(constructorName));
On 2013/08/13 13:03:32, ngeoffray wrote:
> How about adding a class for a js cache that just holds static functions, and
> would do a 'allocate', 'fetch', 'update'.

Done. Performance of micro-benchmark is unaffected.

[ahe, 2013-08-13 17:25:58]

Committed patchset #2 manually as r26065 (presubmit successful).