[LLVMdev] Greetings & Javascript -> LLVM...

[Sean Silva]

I think a good starting point for you would be the work that has gone
into Native Client.

On Sat, Aug 18, 2012 at 11:22 PM, Julian Klappenbach
<jklappenbach at gmail.com> wrote:
> Not necessarily looking for performance gains from LLVM.  Instead, the value
> comes from having a common base platform which can gain language
> independence, address security concerns, support common tooling (debugging,
> editing, etc), and perhaps even introduce common language features
> (annotations / AOP).
>
> I'm envisioning a use case where browsers would utilize this runtime to
> execute not only javascript, but also python, ruby, etc.  Language specific
> interpreters could be downloaded on the fly to support scripts, and security
> would be ensured due to the fact that it would be based within the LLVM
> layer.  The LLVM layer would also provide the access point for common
> browser APIs like access to the DOM and HTML nodes, XSLT, and XHR
> invocations.  This would open up both the browser and current HTML5
> application platforms to a wide variety of languages.   Some may be quite
> happy with Javascript, but I'm sure others would be excited to see that
> stranglehold broken.
>
> And for this purpose, I think LLVM would be well suited.  It really depends
> on how much existing work can be leveraged, and how much interest exists
> within the community to see this happen.
>
> -jjk
>
> On Sat, Aug 18, 2012 at 9:56 PM, Sean Silva <silvas at purdue.edu> wrote:
>>
>> Most of the performance wins for dynamic languages are not from the
>> kinds of optimizations that LLVM does; you basically gain performance
>> by doing run-time specialization of dynamic language constructs to
>> become static, which is something that LLVM really won't help you do,
>> and which practically speaking is extremely language-specific.
>>
>> For example, in JavaScript, all numbers are officially doubles, but in
>> many cases it is profitable to runtime-specialize them to be integers,
>> on the other hand, Python distinguishes between floats and integers,
>> but Python integers overflow into arbitrary-precision integers
>> on-demand.
>>
>> For another example, in Python, dictionaries can have any hashable
>> type as their key, but in JavaScript, "objects" (which double as
>> hashtables) can only have strings as their keys (although numbers get
>> implicitly converted to strings which is another big language-specific
>> optimization opportunity). Oh, and in JavaScript "objects" have a
>> number of additional semantics which prevent them from being actually
>> used as pure hashtables!
>>
>> --Sean Silva
>>
>> On Sat, Aug 18, 2012 at 4:39 PM, Julian Klappenbach
>> <jklappenbach at gmail.com> wrote:
>> > I have a concept for which I'm conducting an initial analysis.  The
>> > broader
>> > idea is to create an LLVM, JIT based runtime that would create a
>> > platform
>> > amenable to scripting languages, but do so while enforcing an optional
>> > sandbox environment when dictated by security concerns (browsers, user
>> > preferences).  With this approach, the community would gain language
>> > independence for browsers, as well as enabling much needed
>> > standardization
>> > over tooling support for debugging, refactoring, and even general
>> > editing
>> > concerns.
>> >
>> > The first language I'd like to tackle is ECMAScript / Javascript.
>> >
>> > So, aside from all the issues with the strategy (getting buy-in from
>> > browser
>> > / tooling teams, development community), my first concern is that it is
>> > even
>> > possible.  Theoretically, it should be possible to express Javascript in
>> > LLVM.  But a quick review of existing projects indicates that, while
>> > LLVM ->
>> > Javascript has been taken on, what I'm seeking has not been done to
>> > date.
>> >
>> > Have I missed anything, or is there any reason not to attempt a project
>> > like
>> > this?
>> >
>> > Regards,
>> >
>> > Julian Klappenbach
>> >
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>> >
>
>