http://blog.mozilla.com/dmandelin Just another Blog.mozilla.com weblog Tue, 07 Oct 2008 22:14:10 +0000 http://backend.userland.com/rss092 en Recently I've been trying to figure out exactly how SquirrelFish Extreme (SFX) is kicking our butts so badly on regexp-dna.js, by about 5x on my machine. Numerically, (WebKit Regular Expression Compiler) WREC provides most of that 5x, but there are some weird twists to the story. My main conclusions: WREC ... http://blog.mozilla.com/dmandelin/2008/10/06/squirrelfishing-in-regexp-dnajs/ I've been in interpreter-land lately, but I do help out a bit with static analysis projects when I get the chance. So I'd better post an update here on some interesting developments that haven't been publicized yet. First, Keith Schwartz (one of our interns) is making great progress on automatic const-correctification ... http://blog.mozilla.com/dmandelin/2008/09/05/static-analysis-newslets/ I've been trying out Chrome on my Vista machine at home, and I read a few hundred comments on Chrome last night on Digg. Here are my first thoughts, just as a browser user and an engineer. Responsiveness. The most noticable things right away are that the UI is minimalistic and ... http://blog.mozilla.com/dmandelin/2008/09/03/chrome-first-look/ It's been a long time since I've posted here-I wanted to post some interesting results about speeding up SpiderMonkey using inline threading, but it turned out to be really hard and took a long time to get close enough to "interesting results". At last, my patch is good enough to ... http://blog.mozilla.com/dmandelin/2008/08/27/inline-threading-tracemonkey-etc/ If you're reading this, chances are that you already know about SquirrelFish, Appl/WebKit's new Javascript implementation. Early tests show SquirrelFish to be 60% faster than WebKit 3.1 JS, 46% faster than Spidermonkey and 52% faster than TT (Tamarin Tracing) on SunSpider. Clearly we have some work to do. The plan is ... http://blog.mozilla.com/dmandelin/2008/06/03/squirrelfish/ Whew. Reading all this TT code is fascinating, but also tiring, hard work. Anyway, I've hit almost all the high points by now, and I've traced out the JITting process all the way from ABC bytecode to native compiled traces. The questions I have left are about how traces actually ... http://blog.mozilla.com/dmandelin/2008/05/28/tamarin-tracing-internals-v-running-compiled-traces/ In part III, I went over how TT generates LIR traces. Now, I'm going to look into the trace optimization and machine code generation process. The code for this is mostly in the nanojit/ directory. Keep in mind that a trace is always straight-line code in SSA form. This makes optimizations ... http://blog.mozilla.com/dmandelin/2008/05/28/tamarin-tracing-internals-iv-trace-optimization/ Program Form 3: LIR. I believe LIR stands for low-level intermediate representation (although I've also heard linear intermediate representation). Typically, in a compiler or VM LIR is the lowest-level (and last) form of machine-independent compiler representation, and looks much like a machine-independent assembly language. TT's LIR plays the same role ... http://blog.mozilla.com/dmandelin/2008/05/23/tamarin-tracing-internals-iii-lir/ The Need for Forth Subroutines. I had a really hard time tracking down how TT adds a pair numbers (ActionScript code like "sum += i") worked until I finally figured out that ECMAScript "+" is not a primitive operation in TT. This makes perfect sense now, as "+" is complicated: ... http://blog.mozilla.com/dmandelin/2008/05/21/tamarin-tracing-interals-part-ii-forth/ Tamarin (technically, tamarin-tracing, henceforth TT)-related projects keep peeking up at me from the horizon. First, there's a good chance I'll have an intern working on TT this summer. And then there's this "Tracehydra" idea. It's a way to connect Spidermonkey's JS parser with the TT execution engine. This is the ... http://blog.mozilla.com/dmandelin/2008/05/16/tamarin-tracing-internals-part-i/