RFR: 8374577: Heap dump from core does not contain HPROF_GC_ROOT_JAVA_FRAME [v2]

[Andrey Turbanov]

On Wed, 7 Jan 2026 06:09:19 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

>> We can extract heap dump from coredump with `jhsdb jmap --binaryheap`, but it does not contain `HPROF_GC_ROOT_JAVA_FRAME`. It means we cannot detect leaked object on thread stack.
>> 
>> I attached 2 images which I saw on Eclipse Memory Analyzer Tool (MAT). Heap dumps were created following options:
>> 
>> 
>> -Xmx256m -XX:+CrashOnOutOfMemoryError -XX:+HeapDumpOnOutOfMemoryError
>> 
>> 
>> <img width="801" height="127" alt="heapdumponoutofmemoryerror" src="https://github.com/user-attachments/assets/7293e909-1c73-465a-a57c-2102251ba463" />
>> 
>> This image shows "thread overview" from the heapdump by `-XX:+HeapDumpOnOutOfMemoryError`. It reports `OOME.main` has large retained heap.
>> 
>> <img width="825" height="87" alt="from-core" src="https://github.com/user-attachments/assets/15fd3d86-76f9-452c-8103-45b631165238" />
>> 
>> On the other hand, this image extracted by `jhsdb jmap --binaryheap` does not report it - leaked object is reported as unreachable objects.
>> 
>> heapDump.cpp in HotSpot dumps `HPROF_GC_ROOT_JAVA_FRAME` for each Java frames. SA should do that.
>> 
>> Essensially, we need to apply the fix in https://github.com/openjdk/jdk/commit/290c5bae15154a9df1c2f3cfd90ebd6de1a20210 , however it fails with exception due to access `oop` in out of range. We need to fix the number of objects in expression stack like HotSpot. I fixed it in https://github.com/openjdk/jdk/commit/0697df16e2aa3f3ace7d82da0a263663fba2e2df . And also I saw error relates to `invokedynamic` because ConstantPool in SA has not followed curre t HotSpot implementation. So I fixed it in https://github.com/openjdk/jdk/pull/29058/commits/a9c9e6c9a345aeb4b2773fd0402342741d180f4d .
>> 
>> This change works fine with both interpreter and `-Xcomp`.
>
> Yasumasa Suenaga has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Update copyright year in ConstantPool.java
>  - Update ClhsdbDumpheap to verify HPROF_GC_ROOT_JAVA_FRAME

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/interpreter/OopMapCacheEntry.java line 99:

> 97:   Method method()        { return method; }
> 98:   int bci()              { return bci; }
> 99:   public int numberOfEntries()  { return maskSize; }

Suggestion:

  public int numberOfEntries() { return maskSize; }

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PR Review Comment: https://git.openjdk.org/jdk/pull/29058#discussion_r2742874729