RFR: JDK-8256725: Metaspace: better blocktree and binlist asserts

[Thomas Stüfe]

Coleen did ask me to crosspost this to hs-dev. I added the label to the gh
issue but skara does not seem to pick it up, so here the manual crosspost.

...Thomas

On Fri, Nov 20, 2020 at 11:06 AM Thomas Stuefe <stuefe at openjdk.java.net>
wrote:

> Hi,
>
> may I have reviews please for this small change.
>
> To analyze JDK-8256572, I'd like to see more information in asserts for
> binlist and blocktree.
>
> This patch:
>
> - beefs up assertion messages when verifying binlist and blocktree
> - adds a canary to the blocktree node to detect overwriters
> - improves the blocktree printing
> - adds a gtest death test to test the overwrite detection.
>
> Thanks!
>
> -------------
>
> Commit messages:
>  - Initial
>
> Changes: https://git.openjdk.java.net/jdk/pull/1339/files
>  Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1339&range=00
>   Issue: https://bugs.openjdk.java.net/browse/JDK-8256725
>   Stats: 120 lines in 5 files changed: 92 ins; 9 del; 19 mod
>   Patch: https://git.openjdk.java.net/jdk/pull/1339.diff
>   Fetch: git fetch https://git.openjdk.java.net/jdk
> pull/1339/head:pull/1339
>
> PR: https://git.openjdk.java.net/jdk/pull/1339
>