RFR: 8358183: [JVMCI] crash accessing nmethod::jvmci_name in CodeCache::aggregate

[Paul Hohensee]

On Tue, 3 Jun 2025 06:39:18 GMT, Boris Ulasevich <bulasevich at openjdk.org> wrote:

> This change addresses an intermittent crash in CompileBroker::print_heapinfo() when accessing JVMCI metadata after a CodeBlob::purge().
> 
> The issue is a regression after:
> - JDK-8343789: JVMCI metadata was moved from nmethod into a separate blob.
> - JDK-8352112: CodeBlob::purge() was updated to set _mutable_data to blob_end().
> 
> The change zeroes out _mutable_data_size, _relocation_size, and _metadata_size in purge() so that after purge jvmci_data_size() returns 0 and CompileBroker::print_heapinfo() won’t touch an invalid _metadata.

Marked as reviewed by phh (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/25608#pullrequestreview-2975990062