[master] RFR: JDK-8325104: Lilliput: Shrink Classpointers [v2]

[Thomas Stuefe]

On Wed, 7 Feb 2024 19:08:12 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> Thomas Stuefe has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 16 commits:
>> 
>>  - Merge branch 'master' into Smaller-ClassPointers
>>  - Merge
>>  - Merge commit 'c1281e6b45ed167df69d29a6039d81854c145ae6~1' into Smaller-ClassPointers
>>  - Fix Typo
>>  - Better CDS arch generation
>>  - Fix error in COH archive generation
>>  - Fixes
>>  - Fix Windows-Only bug that was caused by !INCLUDE_CDS_JAVA_HEAP
>>  - fix runtime/cds/appcds/TestCombinedCompressedFlags and runtime/cds/appcds/CommandLineFlagComboNegative.java
>>  - Fix CdsDifferentCompactObjectHeaders
>>  - ... and 6 more: https://git.openjdk.org/lilliput/compare/da4ffa35...f665504c
>
> src/hotspot/share/memory/metaspace/fence.hpp line 1:
> 
>> 1: /*
> 
> Can you explain the purpose of this? It looks like something that you moved out of test and into main sources. I can't tell from the looks of it what it is.
> EDIT: Ok maybe it's not really moved, except that the filenames match, but the contents is wholly replaced? In any case, GitHub thinks it's a moved file.

Arrgh, these slipped in accidentally. Thanks for catching this.

Metaspace does have a fencing system (overwrite canaries to catch metaspace overwriters). I debated with myself several times whether or not to remove it. Or whether to move the code out of MetaspaceArena. Guess I confused myself enough for this to happen.

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PR Review Comment: https://git.openjdk.org/lilliput/pull/128#discussion_r1485158735