13 ms·

In a comment a bit over a year ago, I noted that JS was being increasingly used as an object code; I asked whether people thought it was suitable for that use.

In a comment a bit over a year ago, I noted that JS was being increasingly used as an object code; I asked whether people thought it was suitable for that use. http://news.ycombinator.com/item?id=792547 http://news.ycombinator.com/item?id=792547 There was some disagreement in the replies to my comment, but the general consensus seemed to be that JS is very suitable for use as an object code. But this article makes me wonder. Increasingly, we're compiling HLLs into an object code that only kinda-sorta has integer arithmetic. Is this a good idea? I'm dubious, to say the least. Certainly this property of JS puts some nontrivial constraints on the design of an HLL that can be efficiently compiled into JS. In any case, interesting post.

gruseom 16y ago
Since I replied in that thread, here's an update. A year's subsequent experience has diluted my enthusiasm, though not too much (say by 20%). JS is an easy language to generate because it's so flexible. Some of its most loosey-goosey weirdnesses (like the arguments pseudo-array) turn out to work really well for representing other languages' constructs (such as, say, named args). The big downside is if you're trying to do anything computationally intensive. To the extent that you want code to do anything numeric or binary, you're in trouble - forced to work at too high and too kludgey a level. Of course JS wasn't designed for anything like this and the fact that we're even talking about it in this context is a testament to fantastic technical and not just market success. A couple side notes... Actionscript is the inverse case, an abominable language that manages to wreak incredible damage on something pretty good (ECMAScript) in surprisingly few steps -- mainly, as far as I can tell, by trying to turn into something "proper" a.k.a Java, a fate that JS itself was fortunately forced to avoid -- but it provides access to one lower level than JS does, and this is a big deal for some kinds of programs. We're probably going to use Flash (when available) as a computational accelerator for this reason. Second, our results suggest that the real gamechanger here is V8. I know that most of the benchmarks out there show Tamarin and other VMs somewhat competitive with V8. Not in our world. I'm talking a couple of orders of magnitude difference. It's astonishing. If everyone would just use Chrome, we would have no performance problems at all.
- acqq 16y ago
  > an abominable language that manages to wreak incredible damage on something pretty good (ECMAScript) in surprisingly few steps Can you please give some specific examples? I'm curious. I think you mention yourself that you can get faster execution with it, so that's the positive side. What's the damage?
  - gruseom 16y ago
    It's all the little things they screw up by trying to turn JS into Java. It seems like that's the way to 'improve' the language (add 'proper' classes, 'proper' typing). But the result is a mishmash. They've added stucco to an oil painting. Sorry for the lack of specific examples, but my way of dealing with the incessant irritations is to deliberately forget them. Even the performance is misleading. It comes from one thing, the static typing, and having played that card there doesn't seem to be anywhere else for them to go. AVM2 bytecode is very interesting; if you try to optimize it you get counterintuitive results: it either stays the same or gets slower. (The one exception is the fast memory opcodes that were added for the abortive Alchemy project, but that's another story.) The proper point of comparison is V8. Adobe had an eternity of a head start. They just bet on the wrong horse. Had they understood the problem more deeply they could have grabbed the V8 guys before Google even thought about it. In that case their head start might have turned into total dominance of the browser runtime. The biggest advantage Flash has -- 95%+ market penetration -- is one of the most valuable assets on the internet. (Is any single asset more valuable? I mean executables, as in IE counts but google.com doesn't.) Imagine if Adobe had done V8 before Chrome existed. The few users who didn't have Flash would have had to install it just to make web apps usable. People might not have bothered for a 2x speedup, but a 1000x speedup? I think so. Edit: to be clear, I'm not talking about (heaven forbid) Flash apps. I'm saying that Flash could have become the standard runtime for web apps. They were on the VM performance track years before anyone else. But it's easy to see that they weren't thinking about this at all, because the facilities for communicating between Flash and the browser are unbelievably poor. (They actually marshal all calls into XML messages! Grrrrrrraaaaaaagh.)
    - acqq 16y ago

gruseom 16y ago

Since I replied in that thread, here's an update. A year's subsequent experience has diluted my enthusiasm, though not too much (say by 20%). JS is an easy language to generate because it's so flexible. Some of its most loosey-goosey weirdnesses (like the arguments pseudo-array) turn out to work really well for representing other languages' constructs (such as, say, named args). The big downside is if you're trying to do anything computationally intensive. To the extent that you want code to do anything numeric or binary, you're in trouble - forced to work at too high and too kludgey a level. Of course JS wasn't designed for anything like this and the fact that we're even talking about it in this context is a testament to fantastic technical and not just market success. A couple side notes... Actionscript is the inverse case, an abominable language that manages to wreak incredible damage on something pretty good (ECMAScript) in surprisingly few steps -- mainly, as far as I can tell, by trying to turn into something "proper" a.k.a Java, a fate that JS itself was fortunately forced to avoid -- but it provides access to one lower level than JS does, and this is a big deal for some kinds of programs. We're probably going to use Flash (when available) as a computational accelerator for this reason. Second, our results suggest that the real gamechanger here is V8. I know that most of the benchmarks out there show Tamarin and other VMs somewhat competitive with V8. Not in our world. I'm talking a couple of orders of magnitude difference. It's astonishing. If everyone would just use Chrome, we would have no performance problems at all.

acqq 16y ago
> an abominable language that manages to wreak incredible damage on something pretty good (ECMAScript) in surprisingly few steps Can you please give some specific examples? I'm curious. I think you mention yourself that you can get faster execution with it, so that's the positive side. What's the damage?
- gruseom 16y ago
  It's all the little things they screw up by trying to turn JS into Java. It seems like that's the way to 'improve' the language (add 'proper' classes, 'proper' typing). But the result is a mishmash. They've added stucco to an oil painting. Sorry for the lack of specific examples, but my way of dealing with the incessant irritations is to deliberately forget them. Even the performance is misleading. It comes from one thing, the static typing, and having played that card there doesn't seem to be anywhere else for them to go. AVM2 bytecode is very interesting; if you try to optimize it you get counterintuitive results: it either stays the same or gets slower. (The one exception is the fast memory opcodes that were added for the abortive Alchemy project, but that's another story.) The proper point of comparison is V8. Adobe had an eternity of a head start. They just bet on the wrong horse. Had they understood the problem more deeply they could have grabbed the V8 guys before Google even thought about it. In that case their head start might have turned into total dominance of the browser runtime. The biggest advantage Flash has -- 95%+ market penetration -- is one of the most valuable assets on the internet. (Is any single asset more valuable? I mean executables, as in IE counts but google.com doesn't.) Imagine if Adobe had done V8 before Chrome existed. The few users who didn't have Flash would have had to install it just to make web apps usable. People might not have bothered for a 2x speedup, but a 1000x speedup? I think so. Edit: to be clear, I'm not talking about (heaven forbid) Flash apps. I'm saying that Flash could have become the standard runtime for web apps. They were on the VM performance track years before anyone else. But it's easy to see that they weren't thinking about this at all, because the facilities for communicating between Flash and the browser are unbelievably poor. (They actually marshal all calls into XML messages! Grrrrrrraaaaaaagh.)
  - acqq 16y ago