Merge pull request #19225 from theresa-m/fix_18907_45

(0.45) Remove generated MHProxy package entries

Author: pshipton

runtime/oti/vm_api.h

@@ -2120,6 +2120,15 @@ hashClassTableAtPut(J9VMThread *vmThread, J9ClassLoader *classLoader, U_8 *class
 UDATA
 hashClassTableDelete(J9ClassLoader *classLoader, U_8 *className, UDATA classNameLength);
 
+/**
+* @brief Remove package entry from hashClassTable
+* @param *classLoader
+* @param *romClass of package to be removed
+* @return UDATA 0 on success, 1 on failure
+*/
+UDATA
+hashClassTablePackageDelete(J9VMThread *vmThread, J9ClassLoader* classLoader, J9ROMClass* romClass);
+
 /**
 * @brief
 * @param *javaVM

runtime/vm/KeyHashTable.c

@@ -57,6 +57,8 @@ static UDATA classLocationHashEqualFn(void *leftKey, void *rightKey, void *userD
 
 static void addLocationGeneratedClass(J9VMThread *vmThread, J9ClassLoader *classLoader, KeyHashTableClassEntry *existingPackageEntry, IDATA entryIndex, I_32 locationType);
 
+static BOOLEAN isMHProxyPackage(J9ROMClass *romClass);
+
 #if defined(J9_EXTENDED_DEBUG)
 static void checkClassAlignment(J9Class *clazz, char const *caller)
 {
@@ -439,6 +441,28 @@ hashClassTableDelete(J9ClassLoader *classLoader, U_8 *className, UDATA className
 	return hashTableRemove(table, &key);
 }
 
+UDATA
+hashClassTablePackageDelete(J9VMThread *vmThread, J9ClassLoader* classLoader, J9ROMClass* romClass)
+{
+	if (isMHProxyPackage(romClass)) {
+		/* This generated package only exists for one hidden class and should be
+		 * removed when its rom class is unloaded. hashClassTable package id's rely
+		 * on there being a valid rom class.
+		 */
+		UDATA result = 0;
+		KeyHashTableClassEntry key;
+		key.tag = (UDATA)romClass | TAG_ROM_CLASS;
+		omrthread_monitor_enter(vmThread->javaVM->classTableMutex);
+		result = hashTableRemove(classLoader->classHashTable, &key);
+		J9UTF8* className = J9ROMCLASS_CLASSNAME(romClass);
+		Trc_VM_hashClassTablePackageDelete(vmThread, romClass, J9UTF8_LENGTH(className), J9UTF8_DATA(className));
+		omrthread_monitor_exit(vmThread->javaVM->classTableMutex);
+		return result;
+	} else {
+		return 0;
+	}
+}
+
 void
 hashClassTableReplace(J9VMThread *vmThread, J9ClassLoader *classLoader, J9Class *originalClass, J9Class *replacementClass)
 {
@@ -543,6 +567,16 @@ hashClassTableNextDo(J9HashTableState *walkState)
 	return (NULL == next) ? NULL : next->ramClass;
 }
 
+static BOOLEAN
+isMHProxyPackage(J9ROMClass *romClass) {
+	const char* mhproxy = "jdk/MHProxy";
+	/* Classes that are not strongly tied to the classloader will have
+	 * J9AccClassAnonClass set. See java.lang.invoke.MethodHandles
+	 */
+	return _J9ROMCLASS_J9MODIFIER_IS_SET(romClass, J9AccClassAnonClass) &&
+		J9UTF8_LITERAL_EQUALS(J9UTF8_DATA(J9ROMCLASS_CLASSNAME(romClass)), sizeof(mhproxy) - 1, mhproxy);
+}
+
 UDATA
 hashPkgTableIDFor(J9VMThread *vmThread, J9ClassLoader *classLoader, J9ROMClass *romClass, IDATA entryIndex, I_32 locationType)
 {
@@ -567,6 +601,16 @@ hashPkgTableIDFor(J9VMThread *vmThread, J9ClassLoader *classLoader, J9ROMClass *
 		KeyHashTableClassEntry *result = NULL;
 		BOOLEAN peekOnly = (J9_CP_INDEX_PEEK == entryIndex);
 
+#if JAVA_SPEC_VERSION >= 22
+		/* OpenJ9 issue 18907 fix rely's on this assertion.
+		 * Generated package names for hidden classes have a
+		 * one to one relationship with the generated class.
+		 */
+		if (isMHProxyPackage(romClass)) {
+			Assert_VM_true(NULL == hashTableFind(table, &key));
+		}
+#endif /* JAVA_SPEC_VERSION >= 22 */
+
 		if (peekOnly) {
 			result = hashTableFind(table, &key);
 			if (NULL == result) {

runtime/vm/j9vm.tdf

@@ -964,3 +964,5 @@ TraceEvent=Trc_VM_criu_after_dump Obsolete Overhead=1 Level=2 Template="After ch
 TraceEvent=Trc_VM_crac_checkpointTo NoEnv Overhead=1 Level=3 Template="-XX:CRaCCheckpointTo=%s"
 TraceEvent=Trc_VM_criu_after_dump Overhead=1 Level=2 Template="After checkpoint criu_dump(), restoreNanoTimeMonotonic (%lld), lastRestoreTimeInNanoseconds (%lld)"
 TraceEvent=Trc_VM_criu_process_restore_start_after_dump Overhead=1 Level=2 Template="After checkpoint criu_dump(), restorePid (%zu), processRestoreStartTimeInNanoseconds (%lld)"
+
+TraceEvent=Trc_VM_hashClassTablePackageDelete Overhead=1 Level=1 Template="hashClassTablePackageDelete %p (%.*s)"

runtime/vm/jvminit.c

@@ -233,6 +233,9 @@ void sidecarExit(J9VMThread* shutdownThread);
 static jint runLoadStage (J9JavaVM *vm, IDATA flags);
 #if defined(J9VM_GC_DYNAMIC_CLASS_UNLOADING)
 static void freeClassNativeMemory (J9HookInterface** hook, UDATA eventNum, void* eventData, void* userData);
+#if JAVA_SPEC_VERSION >= 22
+static void vmHookAnonClassesUnload(J9HookInterface** hook, UDATA eventNum, void* eventData, void* userData);
+#endif /* JAVA_SPEC_VERSION >= 22 */
 #endif /* GC_DYNAMIC_CLASS_UNLOADING */
 static jint runShutdownStage (J9JavaVM* vm, IDATA stage, void* reserved, UDATA filterFlags);
 static jint modifyDllLoadTable (J9JavaVM * vm, J9Pool* loadTable, J9VMInitArgs* j9vm_args);
@@ -7494,7 +7497,11 @@ protectedInitializeJavaVM(J9PortLibrary* portLibrary, void * userData)
 
 #if defined(J9VM_GC_DYNAMIC_CLASS_UNLOADING)
 	vmHooks = getVMHookInterface(vm);
-	if(0 != (*vmHooks)->J9HookRegisterWithCallSite(vmHooks, J9HOOK_VM_CLASS_UNLOAD, freeClassNativeMemory, OMR_GET_CALLSITE(), NULL)) {
+	if(0 != (*vmHooks)->J9HookRegisterWithCallSite(vmHooks, J9HOOK_VM_CLASS_UNLOAD, freeClassNativeMemory, OMR_GET_CALLSITE(), NULL)
+#if JAVA_SPEC_VERSION >= 22
+		|| 0 != (*vmHooks)->J9HookRegisterWithCallSite(vmHooks, J9HOOK_VM_ANON_CLASSES_UNLOAD, vmHookAnonClassesUnload, OMR_GET_CALLSITE(), NULL)
+#endif /* JAVA_SPEC_VERSION >= 22 */
+	) {
 		goto error;
 	}
 #endif
@@ -8115,6 +8122,18 @@ freeClassNativeMemory(J9HookInterface** hook, UDATA eventNum, void* eventData, v
 #endif /* defined(J9VM_OPT_OPENJDK_METHODHANDLE) */
 }
 
+#if JAVA_SPEC_VERSION >= 22
+static void
+vmHookAnonClassesUnload(J9HookInterface** hook, UDATA eventNum, void* eventData, void* userData)
+{
+	J9VMAnonymousClassesUnloadEvent * unloadedEvent = (J9VMAnonymousClassesUnloadEvent *)eventData;
+	J9VMThread * vmThread = unloadedEvent->currentThread;
+	for (J9Class* j9clazz = unloadedEvent->anonymousClassesToUnload; j9clazz; j9clazz = j9clazz->gcLink) {
+		hashClassTablePackageDelete(vmThread, j9clazz->classLoader, j9clazz->romClass);
+	}
+}
+#endif /* JAVA_SPEC_VERSION >= 22 */
+
 #endif /* GC_DYNAMIC_CLASS_UNLOADING */
 
 /**