RFR[XS]: 8238961 Assertion failure in new field layout code when ContendedPaddingWidth == 0.

[coleen.phillimore at oracle.com]

Looks good!
Coleen

On 2/13/20 9:54 AM, Frederic Parain wrote:
> Please review this very small fix in field layout code.
>
> The issue is that option ContendedPaddingWidth can be set to zero,
> causing an assertion failure when trying to create a padding block
> of size zero. One site inserting padding blocks was protected against
> zero padding width, but another site was not. This fix makes the
> second site robust against this case.
>
> CR: https://bugs.openjdk.java.net/browse/JDK-8238961
> Webrev: http://cr.openjdk.java.net/~fparain/8238961/webrev.00/index.html
>
> Testing:
>    - tests test/hotspot/jtreg/runtime/contended manually run with ContendedPaddingWidth
>      forced to zero (tests fails because they are not designed to support the case
>      where the padding width is zero, but the VM doesn’t crash anymore because of the
>      assert)
>    - tier 1-3
>
> Thank you,
>
> Fred
>