On Thu, 8 Oct 2026 08:52:39 GMT, Serguei Spitsyn <[email protected]> wrote:
>> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/oops/FlatArray.java line
>> 37:
>>
>>> 35: // A FlatArray is an array containing flattened value objects.
>>> 36:
>>> 37: public class FlatArray extends ObjArray {
>>
>> Q: Changing the inherited class from `Array` to `ObjArray` is suspisious.
>> The following methods may need overriding: `isObjArray()`,
>> `getOopHandleAt()`, and `getObjAt()`.
>> Also, you may need to check `instanceof ObjArray` use-sites to correctly
>> handle `FlatArray` cases:
>>
>> public Object readObject(Oop oop) throws ClassNotFoundException {
>> . . .
>> } else if (oop instanceof ObjArray){
>> return readObjectArray((ObjArray)oop);
>> } else {
>> return null;
>> }
>> }
>> . . .
>> public boolean doObj(Oop oop) {
>> try {
>>
>> writeHeapRecordPrologue(calculateOopDumpRecordSize(oop));
>> if (oop instanceof TypeArray) {
>> writePrimitiveArray((TypeArray)oop);
>> } else if (oop instanceof ObjArray) {
>> Klass klass = oop.getKlass();
>> ObjArrayKlass oak = (ObjArrayKlass) klass;
>> Klass bottomType = oak.getBottomKlass();
>> if (bottomType instanceof InstanceKlass ||
>> bottomType instanceof TypeArrayKlass) {
>> writeObjectArray((ObjArray)oop);
>> } else {
>> writeInternalObject(oop);
>> }
>> . . .
>> if (oop instanceof Instance || oop instanceof TypeArray) {
>> return true;
>> } else if (oop instanceof ObjArray) {
>> ObjArrayKlass oak = (ObjArrayKlass) oop.getKlass();
>> Klass bottomKlass = oak.getBottomKlass();
>> return bottomKlass instanceof InstanceKlass ||
>> bottomKlass instanceof TypeArrayKlass;
>> } else {
>> return false;
>> }
>> }
>> . . .
>> protected int calculateOopDumpRecordSize(Oop oop) throws IOException {
>> if (oop instanceof TypeArray taOop) {
>> return calculatePrimitiveArrayDumpRecordSize(taOop);
>> } else if (oop instanceof ObjArray oaOop) {
>> Klass klass = oop.getKlass();
>> ObjArrayKlass oak =...
>
> Also, do we have a test coverage for the cases above? It is worth to
> double-check.
`flatArrayOopDesc` in HotSpot inherits `objArrayOopDesc`, so I think SA should
follow it. Then `isObjArray()` keeps to return `true` in `FlatArray`.
I added both `getOopHandleAt()` and `getObjAt()` in new commit. I haven't seen
any failures in jtreg tests. They include oop inspection to scan array
elements. I'm not sure they are enough, but I believe it passed current
criteria.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/32849#discussion_r4225560518
