OpenSSL and panama-foreign

[Maurizio Cimadamore]

Hi Remy,
I've updated the PR:

https://git.openjdk.java.net/jdk/pull/5907

With the fix discussed below.

Your reproducer seems to work fine on my end - but it would be great if 
you could confirm either way.

Thanks!
Maurizio

On 11/11/2021 01:52, Maurizio Cimadamore wrote:
> I think I managed to figure out what introduced the regression.
>
> Basically, it's down to the removal of customization for upcall stubs.
>
> ```
>
> @@ -123,7 +120,7 @@ public static UpcallHandler make(ABIDescriptor 
> abi, MethodHandle target, Calling
>                  .anyMatch(s -> abi.arch.isStackType(s.type()));
>          if (USE_INTRINSICS && isSimple && !usesStackArgs && 
> supportsOptimizedUpcalls()) {
>              checkPrimitive(doBindings.type());
> -            JLI.ensureCustomized(doBindings);
> +            doBindings = 
> insertArguments(exactInvoker(doBindings.type()), 0, doBindings);
>              VMStorage[] args = 
> Arrays.stream(argMoves).map(Binding.Move::storage).toArray(VMStorage[]::new);
>              VMStorage[] rets = 
> Arrays.stream(retMoves).map(Binding.Move::storage).toArray(VMStorage[]::new);
>              CallRegs conv = new CallRegs(args, rets);
>
> ```
>
> If this patch is reverted, then everything works as expected (I've run 
> your `ab` test 10 consecutive times, no crashes). Which seems like a 
> latent bug in the upcall machinery.
>
> That said, I think that, for the time being, it would be best to 
> revert this code to what it was in 17, to avoid these spurious crashes.
>
> I wonder if the reason behind the issue we're seeing is caused by the 
> Addressable vs. MemoryAddress mismatch in the method type - e.g. maybe 
> `exactInvoker(doBindings.type())` doesn't do what we think it should. 
> I'll keep investigating tomorrow (well, later today :-) ).
>
> Cheers
> Maurizio
>
> On 10/11/2021 22:38, Maurizio Cimadamore wrote:
>> And, on this same vein, even with the resource scope handshake 
>> disabled, Tomcat still crashes with the following Java option:
>>
>> export JAVA_OPTS="-XX:+DeoptimizeALot 
>> --enable-native-access=ALL-UNNAMED --add-modules jdk.incubator.foreign"
>>
>> DeoptimizeALot causes frequent deopt events in the VM. The handshake 
>> we use for shared segments also used deopt events. Something got 
>> broken here and the upcall intrinsic doesn't seem to be able to 
>> handle deopt events.
>>
>> Maurizio
>>
>>
>> On 10/11/2021 22:27, Maurizio Cimadamore wrote:
>>> This seems to point at some issues with the shared scope logic 
>>> interacting badly with upcall intrinsics. But neither areas have 
>>> changed significantly since 17, which makes this very odd.