Re: [Info-gnuprologjava] 16-bit VM pointers

[Daniel Thomas]

On 25/11/14 19:19, Matt Lilley wrote:
> Hi,
> 
> I'm not sure if this is the right address; if not, can someone direct me to 
> the right one?
> 
> I noticed today while trying to debug some code that GNU Prolog for Java 
> seems to be limited to 16-bit pointers in the VM. For example, the 
> retry-me-else opcode has a maximum argument of 65535. If you create a 
> predicate with a lot of complicated clauses, this can easily be exhausted, 
> and you end up with pointer truncation, and ultimately undefined behaviour.
> 
> Is there a good reason we cannot extend this to at least 32 bits? I'm happy 
> to write the patch if someone has the time to review it. At the *very* least 
> we should check in InterpretedByteCode that the retryPosition is less than 
> the maximum jump distance and raise an exception if it is.
> 
> Regards,
> Matt

Hello Matt,

I would be happy to review such a patch particularly if it came with
some good test cases.

Regards,

Daniel