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JIT-Less V8

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Re: JIT-Less V8

#111

Post by samcday »

schuay wrote: post #41
samcday wrote: post #32

For a team that has been pushing the cutting edge of Javascript VM performance for many years, it must feel pretty weird to ship a feature that allows one to willingly regress performance so much!

A fast V8 with jitting isn't going away. Jitless V8 is meant for embedders that either cannot or do not want to allocate executable memory at runtime. (Also, in many common real-world workloads the performance regression is minimal.)

I was worried my original comment might be misunderstood, that's why I qualified it as "... allows one to >>willingly<< regress performance...". Looks like it still got misunderstood anyway ;)

Re: JIT-Less V8

#112

Post by pitaj »

bjourne wrote: post #81
pitaj wrote: post #39

Earlier quoted context omitted.

Yes, but when pre-compiling, you implicitly trust the code. JITs like V8 are used to execute arbitrary code on your device, where such an exploit is much more harmful.

Untrue. Dart code for example is AOT compiled but untrusted. Various Javascript implementations are also AOT but also supposed to be used for untrusted code.

I have no idea what you're talking about. Under what circumstances is Dart AOT compiled and run untrusted? No browsers support Dart as a first-class citizen. If you're talking about compiling Dart into JS, that's obviously not what anyone is talking about.

There are no Ecmascript AOT compilers. By definition, Ecmascript must be run with an interpreter. AFAIK with the dynamic complexity of the language it's impossible to AOT compile even without things like `eval` and `new Function`.

A better example would be NaCl which as I understand it runs native machine code in a sandbox.

Re: JIT-Less V8

#113

Post by bjourne »

pitaj wrote: post #112
bjourne wrote: post #81

Earlier quoted context omitted.

Untrue. Dart code for example is AOT compiled but untrusted. Various Javascript implementations are also AOT but also supposed to be used for untrusted code.

I have no idea what you're talking about. Under what circumstances is Dart AOT compiled and run untrusted? No browsers support Dart as a first-class citizen. If you're talking about compiling Dart into JS, that's obviously not what anyone is talking about. There are no Ecmascript AOT compilers. By definition, Ecmascript must be run with an interpreter. AFAIK with the dynamic complexity of the language it's impossible…

What I'm talking about? "Yes, but when pre-compiling, you implicitly trust the code." Citation needed. It's not true at all.

Re: JIT-Less V8

#114

Post by efdee »

whatshisface wrote: post #60
efdee wrote: post #56

Earlier quoted context omitted.

It sounds like you read a lot of articles about why JS is bad, but don't have a lot of experience with it. * 10-day design? Nobody is using Javascript 1.0 anymore. * Typing is available to various extents thanks to Flow and/or Typescript. * Slowness... I don't know what you're referring to. Javascript isn't slow. * null vs undefined. What about them? They are two different things with different meanings. * Dependency…

> NPM insecurity NPM packages can contain malicious code. There's no NPM review process, and you can't point to specific versions to lock in your own reviews (package administrators can change whatever files they'd like). There's no such thing as a verified-safe dependencies list because the file you reviewed last month might not be downloaded today.

You definitely can point to specific versions.

That being said, most package managers can contain malicious code and very few of them actually review their packages.

Besides, any company using NPM seriously probably has their own proxy in front of it, so there's no case of "the file might not be downloadable anymore" if that was already a problem with NPM itself.

Re: JIT-Less V8

#115

Post by geofft »

bjourne wrote: post #113
pitaj wrote: post #112

Earlier quoted context omitted.

I have no idea what you're talking about. Under what circumstances is Dart AOT compiled and run untrusted? No browsers support Dart as a first-class citizen. If you're talking about compiling Dart into JS, that's obviously not what anyone is talking about. There are no Ecmascript AOT compilers. By definition, Ecmascript must be run with an interpreter. AFAIK with the dynamic complexity of the language it's impossible…

What I'm talking about? "Yes, but when pre-compiling, you implicitly trust the code." Citation needed. It's not true at all.

Can you give one example of a case where code is compiled AOT and not trusted during compile time? (Your example of Dart was challenged, and I agree that it is not an example, so a more detailed explanation of why it is an example would count.)

Re: JIT-Less V8

#116

Post by roryokane »

writepub wrote: post #92

THIS is another reason to complain to EU regulators [1], regarding Apple's unfair trade practices. Never before in the history of computing, has a company so blatantly suppressed the competition and gotten away with murder. V8 should not be the one needing re-architecture to meet anti-competitive iOS App Store rules, the rules need to make common sense, and treat the competition fairly. [1]: https://techcrunch.com/20…

Wrong thread – this should have been posted on https://news.ycombinator.com/item?id=19377322.

Re: JIT-Less V8

#117

Post by bjourne »

geofft wrote: post #115
bjourne wrote: post #113

Earlier quoted context omitted.

What I'm talking about? "Yes, but when pre-compiling, you implicitly trust the code." Citation needed. It's not true at all.

Can you give one example of a case where code is compiled AOT and not trusted during compile time? (Your example of Dart was challenged, and I agree that it is not an example, so a more detailed explanation of why it is an example would count.)

Why on earth wouldn't Dart count? It is AOT-compiled and meant to be run untrusted inside a Dart VM inside a web browser. That was the intention of the project even if it was cancelled and the VM deprecated. For more examples, see ActionScript on iOS, TFA itself or any of the myriad of projects trying ti AOT-compile JavaScript. For example https://link.springer.com/article/10.1134/S036176881701008X
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