[Lightning] Re: Bytecode compiler

[Ludovic Courtès]

Hi,

Paolo Bonzini <address@hidden> writes:

> On Fri, Dec 3, 2010 at 10:58, Dok Sander <address@hidden> wrote:
>> Thank you for the fast answer. I'm looking for a low-level virtual machine 
>> and as would be expected
>> I ran into LLVM. LLVM however is not fully GPL-licensed software and I was 
>> trying to find if
>> such an GNU project existed.
>
> LLVM is GPL-compatible.  You can also take a look at GNU libjit, but
> it is less mature than LLVM.

Though experience with VMKit suggested that LLVM is not well suited for
JIT: it’s relatively slow because the main goal is AOT, not JIT, and has
a large memory footprint; see <http://vmkit.llvm.org/>.

In particular, from <http://vmkit.llvm.org/publications/vmkit.html>,
Section 4.3 (“Startup Time”):

  Although LLVM has the advantage of being language-independent and
  generating efficient code, it only performs aggressive optimizations.
  A Java HelloWorld program thus takes 8 seconds to run without any
  optimization activated.

Thanks,
Ludo’.