Merge pull request #7942 from tajila/vt

Add structral comparison barriers
eclipse-openj9 · Dec 9, 2019 · 065e210 · 065e210
2 parents 3f21ca2 + 1317684
commit 065e210
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Showing 8 changed files with 88 additions and 5 deletions.
diff --git a/runtime/gc/gctable.c b/runtime/gc/gctable.c
@@ -179,6 +179,7 @@ J9MemoryManagerFunctions MemoryManagerFunctions = {
 	j9gc_objaccess_copyObjectFields,
 	j9gc_objaccess_copyObjectFieldsToFlattenedArrayElement,
 	j9gc_objaccess_copyObjectFieldsFromFlattenedArrayElement,
+	j9gc_objaccess_structuralCompareFlattenedObjects,
 	j9gc_objaccess_cloneIndexableObject,
 	j9gc_objaccess_asConstantPoolObject,
 #if defined(J9VM_GC_REALTIME)

diff --git a/runtime/gc_base/ObjectAccessBarrier.cpp b/runtime/gc_base/ObjectAccessBarrier.cpp
@@ -1377,6 +1377,58 @@ MM_ObjectAccessBarrier::cloneObject(J9VMThread *vmThread, J9Object *srcObject, J
 	copyObjectFields(vmThread, J9GC_J9OBJECT_CLAZZ_THREAD(srcObject, vmThread), srcObject, objectHeaderSize, destObject, objectHeaderSize);
 }
 
+BOOLEAN
+MM_ObjectAccessBarrier::structuralCompareFlattenedObjects(J9VMThread *vmThread, J9Class *valueClass, j9object_t lhsObject, j9object_t rhsObject, UDATA startOffset)
+{
+	bool result = true;
+	const UDATA *descriptionPtr = (UDATA *) valueClass->instanceDescription;
+	UDATA descriptionBits = 0;
+
+	Assert_MM_true(J9_IS_J9CLASS_VALUETYPE(valueClass));
+
+	if(((UDATA)descriptionPtr) & 1) {
+		descriptionBits = ((UDATA)descriptionPtr) >> 1;
+	} else {
+		descriptionBits = *descriptionPtr++;
+	}
+
+	UDATA descriptionIndex = J9_OBJECT_DESCRIPTION_SIZE - 1;
+	UDATA offset = 0;
+	UDATA limit = valueClass->totalInstanceSize;
+
+	U_32 firstFieldOffset = (U_32) valueClass->backfillOffset;
+	if (0 != firstFieldOffset) {
+		/* subtract padding */
+		offset += firstFieldOffset;
+		descriptionBits >>= 1;
+		descriptionIndex -= 1;
+	}
+
+	while (offset < limit) {
+		/* Determine if the slot contains an object pointer or not */
+		if(descriptionBits & 1) {
+			if (mixedObjectReadObject(vmThread, lhsObject, startOffset + offset, false) != mixedObjectReadObject(vmThread, rhsObject, startOffset + offset, false)) {
+				result = false;
+				break;
+			}
+
+		} else {
+			if (*(fj9object_t *)((UDATA)lhsObject + startOffset + offset) != *(fj9object_t *)((UDATA)rhsObject + startOffset + offset)) {
+				result = false;
+				break;
+			}
+		}
+		descriptionBits >>= 1;
+		if(descriptionIndex-- == 0) {
+			descriptionBits = *descriptionPtr++;
+			descriptionIndex = J9_OBJECT_DESCRIPTION_SIZE - 1;
+		}
+		offset += sizeof(fj9object_t);
+	}
+
+	return result;
+}
+
 /**
  * Copy all of the fields of a value class instance to another value class instance.
  * The source or destination may be a flattened value within another object, meaning
@@ -1415,7 +1467,7 @@ MM_ObjectAccessBarrier::copyObjectFields(J9VMThread *vmThread, J9Class *objectCl
 	}
 
 	const UDATA *descriptionPtr = (UDATA *) objectClass->instanceDescription;
-	UDATA descriptionBits;
+	UDATA descriptionBits = 0;
 	if(((UDATA)descriptionPtr) & 1) {
 		descriptionBits = ((UDATA)descriptionPtr) >> 1;
 	} else {

diff --git a/runtime/gc_base/ObjectAccessBarrier.hpp b/runtime/gc_base/ObjectAccessBarrier.hpp
@@ -224,6 +224,7 @@ class MM_ObjectAccessBarrier : public MM_BaseVirtual
 	virtual j9objectmonitor_t *getLockwordAddress(J9VMThread *vmThread, J9Object *object);
 	virtual void cloneObject(J9VMThread *vmThread, J9Object *srcObject, J9Object *destObject);
 	virtual void copyObjectFields(J9VMThread *vmThread, J9Class *valueClass, J9Object *srcObject, UDATA srcOffset, J9Object *destObject, UDATA destOffset);
+	virtual BOOLEAN structuralCompareFlattenedObjects(J9VMThread *vmThread, J9Class *valueClass, j9object_t lhsObject, j9object_t rhsObject, UDATA startOffset);
 	virtual void cloneIndexableObject(J9VMThread *vmThread, J9IndexableObject *srcObject, J9IndexableObject *destObject);
 	virtual J9Object* asConstantPoolObject(J9VMThread *vmThread, J9Object* toConvert, UDATA allocationFlags);
 	virtual void storeObjectToInternalVMSlot(J9VMThread *vmThread, J9Object** destSlot, J9Object *value);

diff --git a/runtime/gc_base/accessBarrier.cpp b/runtime/gc_base/accessBarrier.cpp
@@ -608,6 +608,16 @@ j9gc_objaccess_cloneObject(J9VMThread *vmThread, J9Object *srcObject, J9Object *
 	return barrier->cloneObject(vmThread, srcObject, destObject);
 }
 
+/**
+ *
+ */
+BOOLEAN
+j9gc_objaccess_structuralCompareFlattenedObjects(J9VMThread *vmThread, J9Class *valueClass, j9object_t lhsObject, j9object_t rhsObject, UDATA startOffset)
+{
+	MM_ObjectAccessBarrier *barrier = MM_GCExtensions::getExtensions(vmThread)->accessBarrier;
+	return barrier->structuralCompareFlattenedObjects(vmThread, valueClass, lhsObject, rhsObject, startOffset);
+}
+
 /**
  * Called by certain specs to copy objects
  */

diff --git a/runtime/gc_base/gc_internal.h b/runtime/gc_base/gc_internal.h
@@ -99,6 +99,7 @@ extern J9_CFUNC void j9gc_objaccess_cloneObject(J9VMThread *vmThread, j9object_t
 extern J9_CFUNC void j9gc_objaccess_copyObjectFields(J9VMThread *vmThread, J9Class *valueClass, J9Object *srcObject, UDATA srcOffset, J9Object *destObject, UDATA destOffset);
 extern J9_CFUNC void j9gc_objaccess_copyObjectFieldsToFlattenedArrayElement(J9VMThread *vmThread, J9ArrayClass *arrayClazz, j9object_t srcObject, J9IndexableObject *arrayRef, I_32 index);
 extern J9_CFUNC void j9gc_objaccess_copyObjectFieldsFromFlattenedArrayElement(J9VMThread *vmThread, J9ArrayClass *arrayClazz, j9object_t destObject, J9IndexableObject *arrayRef, I_32 index);
+extern J9_CFUNC BOOLEAN j9gc_objaccess_structuralCompareFlattenedObjects(J9VMThread *vmThread, J9Class *valueClass, j9object_t lhsObject, j9object_t rhsObject, UDATA startOffset);
 extern J9_CFUNC j9object_t j9gc_objaccess_asConstantPoolObject(J9VMThread *vmThread, j9object_t toConvert, UDATA allocationFlags);
 extern J9_CFUNC jvmtiIterationControl j9mm_iterate_heaps(J9JavaVM *vm, J9PortLibrary *portLibrary, UDATA flags, jvmtiIterationControl(*func)(J9JavaVM *vm, struct J9MM_IterateHeapDescriptor *heapDesc, void *userData), void *userData);
 extern J9_CFUNC int gcStartupHeapManagement(J9JavaVM * vm);

diff --git a/runtime/gc_include/ObjectAccessBarrierAPI.hpp b/runtime/gc_include/ObjectAccessBarrierAPI.hpp
@@ -392,6 +392,23 @@ class MM_ObjectAccessBarrierAPI
 		vmThread->javaVM->memoryManagerFunctions->j9gc_objaccess_copyObjectFieldsFromFlattenedArrayElement(vmThread, arrayClazz, destObject, arrayRef, (I_32)index);
 	}
 
+	VMINLINE BOOLEAN
+	structuralFlattenedCompareObjects(J9VMThread *vmThread, J9Class *valueClass, j9object_t lhsObject, j9object_t rhsObject, UDATA startOffset)
+	{
+#if defined(J9VM_GC_ALWAYS_CALL_OBJECT_ACCESS_BARRIER)
+		return vmThread->javaVM->memoryManagerFunctions->j9gc_objaccess_structuralCompareFlattenedObjects(vmThread, valueClass, lhsObject, rhsObject, startOffset);
+#else /* defined(J9VM_GC_ALWAYS_CALL_OBJECT_ACCESS_BARRIER) */
+		if (j9gc_modron_readbar_none != _readBarrierType) {
+			return vmThread->javaVM->memoryManagerFunctions->j9gc_objaccess_structuralCompareFlattenedObjects(vmThread, valueClass, lhsObject, rhsObject, startOffset);
+		} else {
+			startOffset += valueClass->backfillOffset;
+			UDATA compareSize = mixedObjectGetDataSize(valueClass) - valueClass->backfillOffset;
+
+			return (0 == memcmp((void*)((UDATA)lhsObject + startOffset), (void*)((UDATA)rhsObject + startOffset), (size_t)compareSize));
+		}
+#endif /* defined(J9VM_GC_ALWAYS_CALL_OBJECT_ACCESS_BARRIER) */
+	}
+
 	/**
 	 * Copy valueType from sourceObject to destObject
 	 * See MM_ObjectAccessBarrier::copyObjectFields for detailed description

diff --git a/runtime/oti/j9nonbuilder.h b/runtime/oti/j9nonbuilder.h
@@ -4382,6 +4382,7 @@ typedef struct J9MemoryManagerFunctions {
 	void ( *j9gc_objaccess_copyObjectFields)(struct J9VMThread *vmThread, J9Class* valueClass, j9object_t srcObject, UDATA srcOffset, j9object_t destObject, UDATA destOffset) ;
 	void ( *j9gc_objaccess_copyObjectFieldsToFlattenedArrayElement)(struct J9VMThread *vmThread, J9ArrayClass *arrayClazz, j9object_t srcObject, J9IndexableObject *arrayRef, I_32 index) ;
 	void ( *j9gc_objaccess_copyObjectFieldsFromFlattenedArrayElement)(struct J9VMThread *vmThread, J9ArrayClass *arrayClazz, j9object_t destObject, J9IndexableObject *arrayRef, I_32 index) ;
+	BOOLEAN ( *j9gc_objaccess_structuralCompareFlattenedObjects)(struct J9VMThread *vmThread, J9Class *valueClass, j9object_t lhsObject, j9object_t rhsObject, UDATA startOffset) ;
 	void  ( *j9gc_objaccess_cloneIndexableObject)(struct J9VMThread *vmThread, J9IndexableObject *srcObject, J9IndexableObject *destObject) ;
 	j9object_t  ( *j9gc_objaccess_asConstantPoolObject)(struct J9VMThread *vmThread, j9object_t toConvert, UDATA allocationFlags) ;
 #if defined(J9VM_GC_REALTIME)

diff --git a/runtime/vm/BytecodeInterpreter.hpp b/runtime/vm/BytecodeInterpreter.hpp
@@ -5821,7 +5821,7 @@ done:;
 			} else {
 				j9object_t value = NULL;
 #if defined(J9VM_OPT_VALHALLA_VALUE_TYPES)
-				J9ArrayClass *arrayrefClass = J9OBJECT_CLAZZ(_currentThread, arrayref);
+				J9Class *arrayrefClass = J9OBJECT_CLAZZ(_currentThread, arrayref);
 				if (J9_IS_J9CLASS_FLATTENED(arrayrefClass)) {
 					j9object_t newObjectRef = _objectAllocate.inlineAllocateObject(_currentThread, ((J9ArrayClass*)arrayrefClass)->leafComponentType, false, false);
 
@@ -5840,7 +5840,7 @@ done:;
 						arrayrefClass = VM_VMHelpers::currentClass(arrayrefClass);
 					}
 
-					_objectAccessBarrier.copyObjectFieldsFromFlattenedArrayElement(_currentThread, arrayrefClass, newObjectRef, (J9IndexableObject *) arrayref, index);
+					_objectAccessBarrier.copyObjectFieldsFromFlattenedArrayElement(_currentThread, (J9ArrayClass *) arrayrefClass, newObjectRef, (J9IndexableObject *) arrayref, index);
 					value = newObjectRef;
 				} else
 #endif /* if defined(J9VM_OPT_VALHALLA_VALUE_TYPES) */
@@ -5879,9 +5879,9 @@ done:;
 					rc = THROW_ARRAY_STORE;
 				} else {
 #if defined(J9VM_OPT_VALHALLA_VALUE_TYPES)
-					J9ArrayClass *arrayrefClass = J9OBJECT_CLAZZ(_currentThread, arrayref);
+					J9Class *arrayrefClass = J9OBJECT_CLAZZ(_currentThread, arrayref);
 					if (J9_IS_J9CLASS_FLATTENED(arrayrefClass)) {
-						_objectAccessBarrier.copyObjectFieldsToFlattenedArrayElement(_currentThread, arrayrefClass, value, (J9IndexableObject *) arrayref, index);
+						_objectAccessBarrier.copyObjectFieldsToFlattenedArrayElement(_currentThread, (J9ArrayClass *) arrayrefClass, value, (J9IndexableObject *) arrayref, index);
 					} else 
 #endif /* if defined(J9VM_OPT_VALHALLA_VALUE_TYPES) */
 					{