abort in ZForwarding

[Per Liden]

Hi Stuart,

On 04/08/2019 06:39 PM, Stuart Monteith wrote:
[...]
> This resolves the issue:
> 
> diff -r 6eb8c555644a src/hotspot/share/gc/z/zForwarding.cpp
> --- a/src/hotspot/share/gc/z/zForwarding.cpp    Mon Apr 08 09:44:49 2019 +0100
> +++ b/src/hotspot/share/gc/z/zForwarding.cpp    Mon Apr 08 17:30:18 2019 +0100
> @@ -69,6 +69,11 @@
>       // Check for duplicates
>       for (ZForwardingCursor j = i + 1; j < _entries.length(); j++) {
>         const ZForwardingEntry other = at(&j);
> +      if (!other.populated()) {
> +         // Skip empty entries
> +         continue;
> +       }
> +
>         guarantee(entry.from_index() != other.from_index(), "Duplicate from");
>         guarantee(entry.to_offset() != other.to_offset(), "Duplicate to");
>       }
> 
> Have you already encountered this, shall I create a bug+  patchset ?

Ah, yes. That looks like an oversight after JDK-8221540. Feel free to 
create a bug and send a patch to hotspot-gc-dev. I'll sponsor it.

/Per