Array base offset zero

Signed-off-by: tajila <[email protected]>
eclipse-openj9 · Jul 3, 2024 · 24513b0 · 24513b0
1 parent 2f8672c
commit 24513b0
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Showing 10 changed files with 115 additions and 77 deletions.
diff --git a/runtime/gc_modron_startup/mminit.cpp b/runtime/gc_modron_startup/mminit.cpp
@@ -3323,6 +3323,12 @@ setIndexableObjectHeaderSizeWithDataAddress(J9JavaVM* vm)
 		vm->contiguousIndexableHeaderSize = sizeof(J9IndexableObjectWithDataAddressContiguousFull);
 		vm->discontiguousIndexableHeaderSize = sizeof(J9IndexableObjectWithDataAddressDiscontiguousFull);
 	}
+
+	if (MM_GCExtensions::getExtensions(vm)->isVirtualLargeObjectHeapEnabled) {
+		vm->unsafeIndexableHeaderSize = 0;
+	} else {
+		vm->unsafeIndexableHeaderSize = vm->contiguousIndexableHeaderSize;
+	}
 }
 #endif /* defined(J9VM_ENV_DATA64) */
 
@@ -3336,6 +3342,12 @@ setIndexableObjectHeaderSizeWithoutDataAddress(J9JavaVM* vm)
 		vm->contiguousIndexableHeaderSize = sizeof(J9IndexableObjectContiguousFull);
 		vm->discontiguousIndexableHeaderSize = sizeof(J9IndexableObjectDiscontiguousFull);
 	}
+
+	if (MM_GCExtensions::getExtensions(vm)->isVirtualLargeObjectHeapEnabled) {
+		vm->unsafeIndexableHeaderSize = 0;
+	} else {
+		vm->unsafeIndexableHeaderSize = vm->contiguousIndexableHeaderSize;
+	}
 }
 
 #if defined(OMR_GC_CONCURRENT_SCAVENGER)

diff --git a/runtime/jcl/common/sun_misc_Unsafe.cpp b/runtime/jcl/common/sun_misc_Unsafe.cpp
@@ -38,6 +38,7 @@
 #include "ArrayCopyHelpers.hpp"
 #include "AtomicSupport.hpp"
 #include "ObjectMonitor.hpp"
+#include "UnsafeAPI.hpp"
 #include "VMHelpers.hpp"
 
 extern "C" {
@@ -572,7 +573,7 @@ copyMemory(J9VMThread* currentThread, j9object_t sourceObject, UDATA sourceOffse
 		UDATA destOffset, UDATA actualSize)
 {
 	/* Because array data is always 8-aligned, only the alignment of the offsets (and byte size) need be considered */
-	UDATA const headerSize = J9VMTHREAD_CONTIGUOUS_INDEXABLE_HEADER_SIZE(currentThread);
+	UDATA const headerSize = VM_UnsafeAPI::arrayBase(currentThread);
 	UDATA logElementSize = determineCommonAlignment(sourceOffset, destOffset, actualSize);
 	UDATA sourceIndex = (sourceOffset - headerSize) >> logElementSize;
 	UDATA destIndex = (destOffset - headerSize) >> logElementSize;
@@ -595,7 +596,7 @@ static VMINLINE void
 copyMemoryByte(J9VMThread* currentThread, j9object_t sourceObject, UDATA sourceOffset, j9object_t destObject,
 		UDATA destOffset)
 {
-	UDATA const headerSize = J9VMTHREAD_CONTIGUOUS_INDEXABLE_HEADER_SIZE(currentThread);
+	UDATA const headerSize = VM_UnsafeAPI::arrayBase(currentThread);
 	UDATA sourceIndex = sourceOffset - headerSize;
 	UDATA destIndex = destOffset - headerSize;
 
@@ -695,7 +696,7 @@ Java_sun_misc_Unsafe_setMemory__Ljava_lang_Object_2JJB(JNIEnv *env, jobject rece
 		if (!J9ROMCLASS_IS_PRIMITIVE_TYPE(((J9ArrayClass*)clazz)->componentType->romClass)) {
 			goto illegal;
 		}
-		offset -= J9VMTHREAD_CONTIGUOUS_INDEXABLE_HEADER_SIZE(currentThread);
+		offset -= VM_UnsafeAPI::arrayBase(currentThread);
 		VM_ArrayCopyHelpers::primitiveArrayFill(currentThread, object, (UDATA)offset, actualSize, (U_8)value);
 	}
 	vmFuncs->internalExitVMToJNI(currentThread);

diff --git a/runtime/oti/UnsafeAPI.hpp b/runtime/oti/UnsafeAPI.hpp
@@ -36,7 +36,6 @@
 #include "j9.h"
 #include "ArrayCopyHelpers.hpp"
 #include "ObjectAccessBarrierAPI.hpp"
-#include "ut_j9vm.h"
 #include "VMHelpers.hpp"
 #include "AtomicSupport.hpp"
 
@@ -90,10 +89,6 @@ class VM_UnsafeAPI
  */
 private:
 
-	static VMINLINE UDATA arrayBase(J9VMThread *currentThread) {
-		return J9VMTHREAD_CONTIGUOUS_INDEXABLE_HEADER_SIZE(currentThread);
-	}
-
 	static VMINLINE UDATA logFJ9ObjectSize(J9VMThread *currentThread) {
 		return (4 == J9VMTHREAD_REFERENCE_SIZE(currentThread)) ? 2 : 3;
 	}
@@ -335,6 +330,9 @@ class VM_UnsafeAPI
 protected:
 
 public:
+	static VMINLINE UDATA arrayBase(J9VMThread *currentThread) {
+		return J9VMTHREAD_UNSAFE_INDEXABLE_HEADER_SIZE(currentThread);
+	}
 
 	static VMINLINE void loadFence()
 	{
@@ -526,7 +524,7 @@ class VM_UnsafeAPI
 	compareAndSwapObject(J9VMThread *currentThread, MM_ObjectAccessBarrierAPI *objectAccessBarrier, j9object_t object, UDATA offset, j9object_t *compareValue, j9object_t *swapValue)
 	{
 		bool result = false;
-		
+
 		if (VM_VMHelpers::objectIsArray(currentThread, object)) {
 			UDATA index = convertOffsetToIndex(currentThread, offset, logFJ9ObjectSize(currentThread));
 			result = objectAccessBarrier->inlineIndexableObjectCompareAndSwapObject(currentThread, object, index, *compareValue, *swapValue, true);
@@ -550,7 +548,7 @@ class VM_UnsafeAPI
 	{
 		UDATA logElementSize = 3;
 		bool result = false;
-		
+
 		if (NULL == object) {
 			result = (compareValue == VM_AtomicSupport::lockCompareExchangeU64((U_64*)offset, compareValue, swapValue));
 		} else {
@@ -606,7 +604,9 @@ class VM_UnsafeAPI
 	static VMINLINE j9object_t
 	compareAndExchangeObject(J9VMThread *currentThread, MM_ObjectAccessBarrierAPI *objectAccessBarrier, j9object_t object, UDATA offset, j9object_t *compareValue, j9object_t *swapValue)
 	{
-		Assert_VM_notNull(object);
+		if (J9_UNEXPECTED(NULL != object)) {
+			currentThread->javaVM->internalVMFunctions->triggerAssertion(currentThread, "object is null");
+		}
 
 		j9object_t result = NULL;
 

diff --git a/runtime/oti/j9nonbuilder.h b/runtime/oti/j9nonbuilder.h
@@ -5183,6 +5183,7 @@ typedef struct J9InternalVMFunctions {
 #if defined(J9VM_ZOS_3164_INTEROPERABILITY) && (JAVA_SPEC_VERSION >= 17)
 	I_32 (*invoke31BitJNI_OnXLoad)(struct J9JavaVM *vm, void *handle, jboolean isOnLoad, void *reserved);
 #endif /* defined(J9VM_ZOS_3164_INTEROPERABILITY) && (JAVA_SPEC_VERSION >= 17) */
+	void (*triggerAssertion)(struct J9VMThread *currentThread, const char* message);
 } J9InternalVMFunctions;
 
 /* Jazz 99339: define a new structure to replace JavaVM so as to pass J9NativeLibrary to JVMTIEnv  */
@@ -5427,6 +5428,7 @@ typedef struct J9VMThread {
 	void* gcExtensions;
 	UDATA contiguousIndexableHeaderSize;
 	UDATA discontiguousIndexableHeaderSize;
+	UDATA unsafeIndexableHeaderSize;
 #if defined(J9VM_ENV_DATA64)
 	UDATA isIndexableDataAddrPresent;
 #endif /* defined(J9VM_ENV_DATA64) */
@@ -5604,6 +5606,7 @@ typedef struct J9VMThread {
 #define J9VMTHREAD_OBJECT_HEADER_SIZE(vmThread) (J9VMTHREAD_COMPRESS_OBJECT_REFERENCES(vmThread) ? sizeof(J9ObjectCompressed) : sizeof(J9ObjectFull))
 #define J9VMTHREAD_CONTIGUOUS_INDEXABLE_HEADER_SIZE(vmThread) ((vmThread)->contiguousIndexableHeaderSize)
 #define J9VMTHREAD_DISCONTIGUOUS_INDEXABLE_HEADER_SIZE(vmThread) ((vmThread)->discontiguousIndexableHeaderSize)
+#define J9VMTHREAD_UNSAFE_INDEXABLE_HEADER_SIZE(vmThread) ((vmThread)->unsafeIndexableHeaderSize)
 
 typedef struct JFRState {
 	char *jfrFileName;
@@ -5973,6 +5976,7 @@ typedef struct J9JavaVM {
 	UDATA arrayletLeafLogSize;
 	UDATA contiguousIndexableHeaderSize;
 	UDATA discontiguousIndexableHeaderSize;
+	UDATA unsafeIndexableHeaderSize;
 #if defined(J9VM_ENV_DATA64)
 	UDATA isIndexableDataAddrPresent;
 	BOOLEAN isIndexableDualHeaderShapeEnabled;

diff --git a/runtime/oti/vm_api.h b/runtime/oti/vm_api.h
@@ -1143,6 +1143,17 @@ void
 setCRIUSingleThreadModeJVMCRIUException(J9VMThread *vmThread, U_32 moduleName, U_32 messageNumber);
 #endif /* defined(J9VM_OPT_CRIU_SUPPORT) */
 
+/**
+ * Triggers a VM assertion
+ *
+ * @param currentThread vmthread token
+ * @param message the assertion message
+ *
+ * @return void
+ */
+void
+triggerAssertion(J9VMThread *currentThread, const char* message);
+
 /* ---------------- extendedMessageNPE.cpp ---------------- */
 
 /**

diff --git a/runtime/vm/BytecodeInterpreter.hpp b/runtime/vm/BytecodeInterpreter.hpp
@@ -4249,7 +4249,7 @@ class INTERPRETER_CLASS
 
 			if (J9CLASS_IS_ARRAY(receiverClass)) {
 				I_64 arrayDataSize = J9INDEXABLEOBJECT_SIZE(_currentThread, receiver) * J9ARRAYCLASS_GET_STRIDE(receiverClass);
-				I_64 headerSize = J9VMTHREAD_CONTIGUOUS_INDEXABLE_HEADER_SIZE(_currentThread);
+				I_64 headerSize = J9VMTHREAD_UNSAFE_INDEXABLE_HEADER_SIZE(_currentThread);
 				returnDoubleFromINL(REGISTER_ARGS, arrayDataSize + headerSize, 2);
 			} else {
 				I_64 headerSize = (I_64)J9VMTHREAD_OBJECT_HEADER_SIZE(_currentThread);