> The static compiler that preceded HHVM was started in a different time; it was 2008, and the JavaScript wars were just getting started. Conventional wisdom (to anybody who hadn't worked on Self in the late '90's) was that running dynamic languages fast was just kind of a lost cause.
To be fair, LuaJIT has been blazing trails in running dynamic languages fast since 2005. But maybe it wasn't well-known enough to make its way into conventional wisdom.
Of course. I have kind of a difficult line to walk here; I would like to be respectful to both the authors of the HPHPc compiler, which is a really impressive achievement, and to the many many efforts past and present at running dynamic languages. LuaJIT, various SmallTalk systems, Self systems, Erlang, HPHPc, the JVM body of work, V8,hardware-level binary translators, ... are all among the shoulders we are standing on.
All that said: I get the impression reading the comments here of an emerging misconception that "everybody knows" the right way to run these languages fast. We emphatically do not know. It is still a research problem. Heck, garbage collection, a proper subset of the problem area we're talking about here, is still pretty wide open. Given the smart people who have given decades of their career to it, we should not expect there to be a single, silver-bullet technique that cleanly maps all these dynamic languages to high-performance machine code.
So we need more than one project in the air. Some of those projects should explore whole-program analysis, like HPHPc and some of Agesen's offline work on Self, and decades of Lisp compilers. Some of them should explore runtime techniques like tracing and inline-caching. Some of them should explore unifying these approaches. We need them all.
Well purly emphatically we know nothing about compilers. Since I know what a JIT is I really like them so Im bias.
I think there has been so much work put into static compiler for lisps and other dynamic languages but there is not that much to show for it. I mean sure the lisp compilers are really fast but most of the time they get there by throwing away safty and providing typehints. While the work on self was done by one researchteam. The same with LuaJit one guy writes something for a dynamic languages and without adding typehints it starts to perform like crazy.
I think the Lisp community and the rest of the world really missed out on the JIT advantsments. Self was allready fast but Sun picked Oak (Java) to be there Weblanguage (anybody know more about that?).
WRT Self: some of Agesen's work on Self work for doing type inference on conventional, ahead-of-time compilation, and they got pretty good results this way! More interestingly, the opportunities the AOT compiler found were different than the opportunities the JIT compiler found, so there is some hope that they will combine constructively. See. e.g., http://www.cs.ucla.edu/~palsberg/paper/spe95.pdf
To be fair, LuaJIT has been blazing trails in running dynamic languages fast since 2005. But maybe it wasn't well-known enough to make its way into conventional wisdom.