Jens Johansen
0c2d7decd7
The analyzer makes a copy of `lineStarts` without the last element,
and copying it in to a `Uint16List` or an `Uint32List` depending on
what's needed (to avoid using more ram than necessary).
Because the (actual) scanner (`AbstractScanner`) does the same trick
with `Uint16List`/`Uint32List` the linestarts output from the scanner,
while a `List<int>`, is actually a `LineStarts` class, and copying that
into a `Uint16List` (or `Uint32List`) goes into
`_TypedIntListMixin._SlowSetRange` which as the name suggests is slower
than it has to be.
This CL puts the copying into the `LineStarts` class where it actually
has a `Uint16List`/`Uint32List` already, and doing the copy from that
instead avoids the slowdown.
Numbers from `perf stat`:
Before:
```
39,552,191,101 instructions:u
39,552,058,132 instructions:u
39,552,065,649 instructions:u
```
After:
```
39,419,426,977 instructions:u
39,419,429,914 instructions:u
39,419,441,613 instructions:u
```
Saving: about 132 million instructions.
Change-Id: Ibf6c7f6cc9324a54d2bd99c37058103af106164c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/508580
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Dart
An approachable, portable, and productive language for high-quality apps on any platform
Dart is:
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Approachable: Develop with a strongly typed programming language that is consistent, concise, and offers modern language features like null safety and patterns.
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Productive: Make changes iteratively: use hot reload to see the result instantly in your running app. Diagnose app issues using DevTools.
Dart's flexible compiler technology lets you run Dart code in different ways, depending on your target platform and goals:
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