On Wed, 21 Oct 2026 02:26:26 GMT, Yasumasa Suenaga <[email protected]> wrote:
>> Valhalla introduced flattened value object, however SA cannot dump it into
>> heapdump e.g. `jhsdb jmap --binaryheap`.
>> Actually HeapHprofBinWriter.java has following lines. Hence the user cannot
>> check flattened object from heapdump generated by SA.
>>
>>
>> case JVM_SIGNATURE_CLASS:
>> case JVM_SIGNATURE_ARRAY: {
>> if (field.isFlat()) {
>> // FIXME - we don't handle flattened fields yet. Just treat
>> them
>> // as a null reference. See JDK-8381370.
>> writeObjectID(null);
>>
>>
>> This PR addressed it.
>>
>> ---------
>> - [x] I confirm that I make this contribution in accordance with the
>> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai).
>
> Yasumasa Suenaga has updated the pull request with a new target base due to a
> merge or a rebase. The incremental webrev excludes the unrelated changes
> brought in by the merge/rebase. The pull request contains four additional
> commits since the last revision:
>
> - Re-enable HeapDumpTestWithActiveProcess.java
> - Merge branch 'master' into JDK-8381370
> - Use getFieldHolder() rather than getKlass()
> - 8381370: SA is not writing out flattened fields to the hprof file
src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/utilities/HeapHprofBinWriter.java
line 1301:
> 1299: long id = generateIDForFlatObj();
> 1300: flatObjects.push(new DumperFlatObject(id, fieldKlass,
> (FlattenedValue)((OopField)field).getValue(oop)));
> 1301: writeObjectID(id);
The GXL code needs something similar to this, but that can probably be a
separate CR, and maybe not worth ever implementing. Also optional is an
intermediate step that writes out a null ID for flattened references similar to
the writeObjectID(null) that used to be done here for flat arrays. For GXL it
would look something like:
// emit a node for null
out.print("<node id='");
out.print(getID(null));
out.println("'/>");
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/33395#discussion_r4342405915
