Last week in WebKit:
staying above 50 mph

This year’s WebKit Contributors Meeting is almost there: it starts next Thursday. The Contributors meeting is a great opportunity for contributors to discuss the future of WebKit.

If you are attending, don’t forget to prepare demos if you have anything cool to show, and update the wiki with suggestions for the Talks/Hackathons.

New exposed behaviors

Joseph Pecoraro added column numbers to the error messages displayed in the Inspector console.

Allan Sandfeld Jensen added support for mouseenter and mouseleave events. These are enabled by default and available for testing in the nightly builds.

Engine engineering

There were a lot of performance optimizations this week. I cannot really list half of them so here are some cool random ones:

  • Ryosuke Niwa, after banging his head on the wall for a couple of days, improved the performance of rendering a new selection by 20%.
  • Antti Koivisto and Andreas Kling made a few changes to avoid recomputing the style when possible.
  • Roman Zhuykov made a nice little DFG optimization. A little context: in JavaScript, double values have a negative zero: -0.0, while negative integer are represented with two’s complement do not have a negative zero. Roman changed the code generation to avoid checking for negative zero when certain conditions are met.
  • Oliver Hunt added support for JavaScript Math.imul, and made it fast with baseline JIT and DFG implementations.

Some other stuff happening:

The WebKitten of the week is Christophe Dumez for his great work on the binding generator and WebKit’s WebIDLs! It looks like we may have a new maintainer for the code generators.

Things to look forward to: