RFR: JDK-8298445: Add LeakSanitizer support in HotSpot [v6]

[Justin King]

On Tue, 7 Feb 2023 15:40:34 GMT, Justin King <jcking at openjdk.org> wrote:

>> Adds initial LSan (LeakSanitizer) support to Hotspot. This setup has been used to identify multiple leaks so far. It can run most of the test suite except those that also fail with ASan, which is being looked at separately. It is especially useful when combined with ASan, as LSan can use poisoning information to determine what memory to scan or not to scan, making leak detection more accurate and faster.
>> 
>> **Suppressing:**
>> Currently the suppression list is only used to suppress JLI leaks that are known, the rest are done in code. Suppressing needs to identify the source of thet leak. Due to Hotspot's code organization, we would need to suppress `os::malloc` and friends, which would suppress everything. Suppressing in code has the added benefit of being explicit and surviving refactors if methods change.
>> 
>> **Caveats:**
>> - By default ASan enables LSan, however we explicitly disable it unless `--enable-lsan` is given. It is useful to be able to use ASan without LSan. Using LSan by itself is less likely to be useful and will probably not work, but its still possible currently.
>
> Justin King has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Revert changes to JDK
>   
>   Signed-off-by: Justin King <jcking at google.com>

I did integrate assuming somebody from Hotspot would sponsor. Does the bot/tooling not ensure reviews from applicable reviewers? If not, that seems non-ideal itself.

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PR: https://git.openjdk.org/jdk/pull/12229