[jdk17] RFR: 8268676: assert(!ik->is_interface() && !ik->has_subklass()) failed: inconsistent klass hierarchy

[Roland Westrelin]

On Tue, 15 Jun 2021 21:58:45 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

> JDK-8267947 disabled the caching for "has_subklass() == false" and it became
> more likely to observe class hierarchy changes when concurrent class loading
> happens.
> 
> `ArrayCopy` optimization may observe an effectively exact klass and proceed,
> but the observation can be invalidated later.
> 
> Proposed fix turns the problematic assert into a runtime check which bails out
> the transformation if src input doesn't have exact klass type anymore.
> 
> Testing:
> - [x] hs-tier1 - hs-tier2

Looks good.

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Marked as reviewed by roland (Reviewer).

PR: https://git.openjdk.java.net/jdk17/pull/67