Support tracing reference on continuation java frames for jvmti

Jvmti trace live heap objects via j9gc_ext_reachable_objects_do (MM_ReferenceChainWalker), update MM_ReferenceChainWalker to support to trace the references on the java frames of continuation. - only unmounted continuations would be scanned via scanContinuationObject(), the mounted continuation would be scanned via scanThread (thread->currentContinuation). Signed-off-by: Lin Hu <[email protected]>
eclipse-openj9 · Sep 28, 2023 · 56a0a9c · 56a0a9c
1 parent 32a6198
commit 56a0a9c
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Showing 2 changed files with 44 additions and 1 deletion.
diff --git a/runtime/gc_base/ReferenceChainWalker.cpp b/runtime/gc_base/ReferenceChainWalker.cpp
@@ -352,11 +352,13 @@ MM_ReferenceChainWalker::scanObject(J9Object *objectPtr)
 	case GC_ObjectModel::SCAN_ATOMIC_MARKABLE_REFERENCE_OBJECT:
 	case GC_ObjectModel::SCAN_MIXED_OBJECT:
 	case GC_ObjectModel::SCAN_OWNABLESYNCHRONIZER_OBJECT:
-	case GC_ObjectModel::SCAN_CONTINUATION_OBJECT:
 	case GC_ObjectModel::SCAN_CLASS_OBJECT:
 	case GC_ObjectModel::SCAN_CLASSLOADER_OBJECT:
 		scanMixedObject(objectPtr);
 		break;
+	case GC_ObjectModel::SCAN_CONTINUATION_OBJECT:
+		scanContinuationObject(objectPtr);
+		break;
 	case GC_ObjectModel::SCAN_POINTER_ARRAY_OBJECT:
 		scanPointerArrayObject((J9IndexableObject *)objectPtr);
 		break;
@@ -375,6 +377,44 @@ MM_ReferenceChainWalker::scanObject(J9Object *objectPtr)
 	}
 }
 
+/**
+ * @todo Provide function documentation
+ */
+void
+stackSlotIteratorForReferenceChainWalker(J9JavaVM *javaVM, J9Object **slot, void *localData, J9StackWalkState *walkState, const void *stackLocation)
+{
+	StackIteratorData *data = (StackIteratorData *)localData;
+	data->rootScanner->doStackSlot(slot, walkState, stackLocation);
+}
+
+/**
+ * @todo Provide function documentation
+ */
+MMINLINE void
+MM_ReferenceChainWalker::scanContinuationNativeSlots(J9Object *objectPtr)
+{
+	J9VMThread *currentThread = (J9VMThread *)_env->getLanguageVMThread();
+	const bool isConcurrentGC = false;
+	const bool isGlobalGC = false;
+	const bool beingMounted = false;
+	if (MM_GCExtensions::needScanStacksForContinuationObject(currentThread, objectPtr, isConcurrentGC, isGlobalGC, beingMounted)) {
+		StackIteratorData localData;
+		localData.rootScanner = this;
+
+		GC_VMThreadStackSlotIterator::scanContinuationSlots(currentThread, objectPtr, (void *)&localData, stackSlotIteratorForReferenceChainWalker, false, false);
+	}
+}
+
+/**
+ * @todo Provide function documentation
+ */
+void
+MM_ReferenceChainWalker::scanContinuationObject(J9Object *objectPtr)
+{
+	scanContinuationNativeSlots(objectPtr);
+	scanMixedObject(objectPtr);
+}
+
 /**
  * @todo Provide function documentation
  */

diff --git a/runtime/gc_base/ReferenceChainWalker.hpp b/runtime/gc_base/ReferenceChainWalker.hpp
@@ -90,6 +90,9 @@ class MM_ReferenceChainWalker : public MM_RootScanner
 	virtual void scanMixedObject(J9Object *objectPtr);
 	virtual void scanPointerArrayObject(J9IndexableObject *objectPtr);
 	virtual void scanReferenceMixedObject(J9Object *objectPtr);
+
+	MMINLINE void scanContinuationNativeSlots(J9Object *objectPtr);
+	MMINLINE void scanContinuationObject(J9Object *objectPtr);
 
 	virtual void doClassLoader(J9ClassLoader *classLoader);