llvm dev - Oct 2006 - [LLVMdev] lli in interpreter mode and external native libraries

Chris Lattner wrote:
>
> The JIT has a superset of this functionality.  However, if there is JIT 
> support for the host that you are interested in, you shouldn't have to
use
> the interpreter at all.
>
>   
For interpreting, yes, but model checking is weirder so it's greatly 
beneficial to be able to heavily hack an interpreter.
>> I can't really move to using the JIT entirely because I want to
replace
>> the memory model with something that supports backtracking -- this is
>> doable (fairly) straightforwardly with the interpreter, but it would
>> require some very complicated transformations to the code in order to
do
>> this within the JIT environment, and it would be quite tricky to avoid
>> subtly breaking the semantics. That kind of approach is possible,
>> probably, but not really something I want to attack right now.
>>     
>
> Ok.  The easiest (in some senses) approach would be to do what you say 
> above.  However, you could probably arrange for a mixed approach to work. 
> in particular, you could have the JIT dynamically compile the FFI code you 
> need by dynamically generating the "unpack from GenericValue"
code for
> each callee you are interested in.
>   
That's what I'm currently trying -- it looks reasonably straightforward.

Sarah

>>> I can't really move to using the JIT entirely because I want to
replace
>>> the memory model with something that supports backtracking -- this
is
>>> doable (fairly) straightforwardly with the interpreter, but it
would
>>> require some very complicated transformations to the code in order
to do
>>> this within the JIT environment, and it would be quite tricky to
avoid
>>> subtly breaking the semantics. That kind of approach is possible,
>>> probably, but not really something I want to attack right now.
>>>     
>>>       
>> Ok.  The easiest (in some senses) approach would be to do what you say 
>> above.  However, you could probably arrange for a mixed approach to
work.
>> in particular, you could have the JIT dynamically compile the FFI code
you
>> need by dynamically generating the "unpack from GenericValue"
code for
>> each callee you are interested in.
>>   
>>     
> That's what I'm currently trying -- it looks reasonably
straightforward.
>
>   
... and, at least on 32-bit Linux, it works fine. Thanks for the help. :-)

Sarah

On Fri, 27 Oct 2006, Sarah Thompson wrote:
>> That's what I'm currently trying -- it looks reasonably
straightforward.
> ... and, at least on 32-bit Linux, it works fine. Thanks for the help. :-)
Cool!

-Chris

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