[foreign-memaccess+abi] RFR: 8266626: Check that the target address of a native call is not NULL [v2]

[Jorn Vernee]

On Mon, 10 May 2021 11:40:08 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> This patch adds a check when unboxing the target address of a native call to check that the address is not `NULL`. Additionally, it adds checks earlier when an address is specified with a linking request, to check that that address is not `NULL`.
>> 
>> I didn't see any regressions on the CallOverhead* benchmarks.
>> 
>> Thanks,
>> Jorn
>
> Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:
> 
>   - Merge check symbol code
>   - add missing documentation

I've addressed review comments:
 - Move symbol check into shared code, this also makes sure we do a more explicit `null` check in the virtual case.
 - added some documentation about the thrown exceptions.

-------------

PR: https://git.openjdk.java.net/panama-foreign/pull/530