[pypy-dev] Re: Fwd: michele.simionato at gmail.com: ACCU conference aftermath

[Steven H. Rogers]

Michael Hudson wrote:
> Armin Rigo <arigo at tunes.org> writes:
> 
> 
>>Hi all,
>>
>>I took the liberty to forward here the following e-mail from Michele 
>>Simionato, as it contains interesting links.
> 
> I think Michele is using a different definition of "JIT" to me...
> 
>>As I told you in the conference, I think you should check in the
>>Lisp/Scheme world where there is an astonishingly amount of
>>knowledge about JIT and in general about compiling to C code fast.
> 
> 
> While not disputing the general thrust of this, I would say that I am
> aware of *no* work on using run-time information to improve
> compilation in a Lisp or a Scheme system (this surprises me, and I
> have looked for it a bit, but I may have missed something).
> 

While not automated like a Java JIT, the compiler is an integral part of the 
language in Lisp and may be used by the application programmer to compile 
code at run time.  SBCL uses this in it's REPL to give the illusion of an 
interpreter; each expression is compiled as it is read.  AFAIK, run time 
optimizations are the responsibility of the application.

> Also, very few serious common lisp implementations go via C (the only
> one I can think of that does is GCL).
> 

CLISP is written in largely in C.  SBCL has replaced much of the assembler 
in CMUCL with C for greater portability.

> 
>>Relevant projects I know of are:
>>
>>- SBCL, a JIT compiler for Common Lisp;
> 
> 
> SBCL is not a JIT compiler in the sense I understand the words.
> 

What is your understanding of JIT compiler?

-- 
Steven H. Rogers, Ph.D., steve at shrogers.com
Weblog: http://shrogers.com/weblog
"Reach low orbit and you're half way to anywhere in the Solar System."
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