[webkit-dev] The SquirrelFish Cometh

Maciej Stachowiak mjs at apple.com
Sat May 17 19:03:37 PDT 2008

Hi Everyone,

Over the past few weeks, a few of us have been working on a major  
reworking of the JavaScriptCore interpreter, code named  
"SquirrelFish". This work has been done mainly by Geoff Garen, Oliver  
Hunt and Cameron Zwarich, with help from myself, Sam Weinig, and  
occasional others. The classic version of JavaScriptCore is an AST- 
based interpreter. Although it was highly tuned, and competitive with  
advanced bytecode engines in benchmarks, we could see that we would  
run into the limits of the architecture soon.

So we started SquirrelFish, an incremental rewrite of JavaScriptCore's  
execution logic to convert it into a state-of-the art bytecode VM.  
Most of this work has been done on a branch of the public SVN  
repository, to avoid destabilizing the trunk. We are now very close to  
finishing off the last few blockers. There will be a formal  
announcement to the general public when we are ready, including  
performance data and more details about the internals. But for now I  
wanted to let WebKit insiders know that it is coming.

We are also at the point where we could use testing help to verify  
that SquirrelFish can handle the real-world web. If anyone would like  
to help test, and is willing to get their hands a bit dirty, check out  


More information about the webkit-dev mailing list