RFR: 8340297: Use-after-free recognition for metaspace and class space [v6]

[Thomas Stuefe]

On Fri, 22 Aug 2025 10:53:30 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

>> Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   remove stray macro
>
> src/hotspot/share/oops/metadata.hpp line 47:
> 
>> 45:   static constexpr uint32_t common_prefix_mask   = 0xFFFF0000;
>> 46:   static constexpr uint32_t instance_klass_token = 0x3E7A0101;
>> 47:   static constexpr uint32_t array_klass_token    = 0x3E7A0102;
> 
> Why not
> 
> ```c++
> enum class Token : uint32_t { /* cases */ };

What would be the advantage, apart from having to prefix all tokens with `Metadata::Token::` now?

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PR Review Comment: https://git.openjdk.org/jdk/pull/25891#discussion_r2299906109