Integrated: 8316694: Implement relocation of nmethod within CodeCache

[Chad Rakoczy]

On Tue, 11 Feb 2025 22:05:13 GMT, Chad Rakoczy <duke at openjdk.org> wrote:

> This PR introduces a new function to replace nmethods, addressing [JDK-8316694](https://bugs.openjdk.org/browse/JDK-8316694). It enables the creation of new nmethods from existing ones, allowing method relocation in the code heap and supporting [JDK-8328186](https://bugs.openjdk.org/browse/JDK-8328186).
> 
> When an nmethod is replaced, a deep copy is performed. The corresponding Java method is updated to reference the new nmethod, while the old one is marked as unused. The garbage collector handles final cleanup and deallocation.
> 
> This does not modify existing code paths and therefore does not benefit much from existing tests. New tests were created to test the new functionality
> 
> Additional Testing:
> - [x] Linux x64 fastdebug tier 1/2/3/4
> - [x] Linux aarch64 fastdebug tier 1/2/3/4

This pull request has now been integrated.

Changeset: f740cd2a
Author:    Chad Rakoczy <chadrako at amazon.com>
Committer: Evgeny Astigeevich <eastigeevich at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/f740cd2aad43a008da1ed1ff15ebe2c790f893a0
Stats:     1593 lines in 26 files changed: 1529 ins; 2 del; 62 mod

8316694: Implement relocation of nmethod within CodeCache

Reviewed-by: kvn, eosterlund, never, eastigeevich, bulasevich

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PR: https://git.openjdk.org/jdk/pull/23573