Merge pull request #16325 from babsingh/null_checks_vt_list

Add asserts and tracepoints in JVM_VirtualThread* functions
eclipse-openj9 · Nov 16, 2022 · e5ee930 · e5ee930
2 parents 4c499f8 + 744ab4a
commit e5ee930
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Showing 2 changed files with 107 additions and 13 deletions.
diff --git a/runtime/j9vm/j9scar.tdf b/runtime/j9vm/j9scar.tdf
@@ -1,4 +1,4 @@
-// Copyright (c) 2006, 2021 IBM Corp. and others
+// Copyright (c) 2006, 2022 IBM Corp. and others
 //
 // This program and the accompanying materials are made available under
 // the terms of the Eclipse Public License 2.0 which accompanies this
@@ -350,3 +350,17 @@ TraceEvent=Trc_SC_LoadLibrary_OpenShared NoEnv Overhead=1 Level=3 Template="JVM_
 TraceEvent=Trc_SC_LoadLibrary_OpenShared_Decorate NoEnv Overhead=1 Level=3 Template="JVM_LoadLibrary(name=%s) j9sl_open_shared_library J9PORT_SLOPEN_DECORATE"
 
 TraceExit=Trc_SC_LoadLibrary_Exit NoEnv Overhead=1 Level=2 Template="JVM_LoadLibrary -- return 0x%zx"
+
+TraceEntry=Trc_SC_VirtualThreadMountBegin_Entry Overhead=1 Level=3 Template="thread = 0x%p, firstMount = %d"
+TraceExit=Trc_SC_VirtualThreadMountBegin_Exit Overhead=1 Level=3 Template="thread = 0x%p, firstMount = %d"
+
+TraceEntry=Trc_SC_VirtualThreadMountEnd_Entry Overhead=1 Level=3 Template="thread = 0x%p, firstMount = %d"
+TraceExit=Trc_SC_VirtualThreadMountEnd_Exit Overhead=1 Level=3 Template="thread = 0x%p, firstMount = %d"
+
+TraceEntry=Trc_SC_VirtualThreadUnmountBegin_Entry Overhead=1 Level=3 Template="thread = 0x%p, lastUnmount = %d"
+TraceExit=Trc_SC_VirtualThreadUnmountBegin_Exit Overhead=1 Level=3 Template="thread = 0x%p, lastUnmount = %d"
+
+TraceEntry=Trc_SC_VirtualThreadUnmountEnd_Entry Overhead=1 Level=3 Template="thread = 0x%p, lastUnmount = %d"
+TraceExit=Trc_SC_VirtualThreadUnmountEnd_Exit Overhead=1 Level=3 Template="thread = 0x%p, lastUnmount = %d"
+
+TraceEvent=Trc_SC_VirtualThread_Info Overhead=1 Level=3 Test Template="virtualThreadObj = 0x%p, virtualThreadState = 0x%p, virtualThreadInspectorCount = %lld, carrierThreadObj = 0x%p, continuationObj = 0x%p, J9VMContinuation = 0x%p"
diff --git a/runtime/j9vm/javanextvmi.cpp b/runtime/j9vm/javanextvmi.cpp
@@ -19,7 +19,6 @@
  *
  * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
  *******************************************************************************/
-#include <assert.h>
 #include <jni.h>
 
 #include "bcverify_api.h"
@@ -52,13 +51,13 @@ extern IDATA (*f_monitorNotifyAll)(omrthread_monitor_t monitor);
 JNIEXPORT void JNICALL
 JVM_DefineArchivedModules(JNIEnv *env, jobject obj1, jobject obj2)
 {
-	assert(!"JVM_DefineArchivedModules unimplemented");
+	Assert_SC_true(!"JVM_DefineArchivedModules unimplemented");
 }
 
 JNIEXPORT void JNICALL
 JVM_LogLambdaFormInvoker(JNIEnv *env, jstring str)
 {
-	assert(!"JVM_LogLambdaFormInvoker unimplemented");
+	Assert_SC_true(!"JVM_LogLambdaFormInvoker unimplemented");
 }
 
 JNIEXPORT jboolean JNICALL
@@ -188,13 +187,13 @@ JVM_GetExtendedNPEMessage(JNIEnv *env, jthrowable throwableObj)
 JNIEXPORT void JNICALL
 JVM_DumpClassListToFile(JNIEnv *env, jstring str)
 {
-	assert(!"JVM_DumpClassListToFile unimplemented");
+	Assert_SC_true(!"JVM_DumpClassListToFile unimplemented");
 }
 
 JNIEXPORT void JNICALL
 JVM_DumpDynamicArchive(JNIEnv *env, jstring str)
 {
-	assert(!"JVM_DumpDynamicArchive unimplemented");
+	Assert_SC_true(!"JVM_DumpDynamicArchive unimplemented");
 }
 #endif /* JAVA_SPEC_VERSION >= 17 */
 
@@ -213,21 +212,21 @@ JVM_IsFinalizationEnabled(JNIEnv *env)
 JNIEXPORT void JNICALL
 JVM_ReportFinalizationComplete(JNIEnv *env, jobject obj)
 {
-	assert(!"JVM_ReportFinalizationComplete unimplemented");
+	Assert_SC_true(!"JVM_ReportFinalizationComplete unimplemented");
 }
 #endif /* JAVA_SPEC_VERSION >= 18 */
 
 #if JAVA_SPEC_VERSION >= 19
 JNIEXPORT void JNICALL
 JVM_LoadZipLibrary(void)
 {
-	assert(!"JVM_LoadZipLibrary unimplemented");
+	Assert_SC_true(!"JVM_LoadZipLibrary unimplemented");
 }
 
 JNIEXPORT void JNICALL
 JVM_RegisterContinuationMethods(JNIEnv *env, jclass clz)
 {
-	assert(!"JVM_RegisterContinuationMethods unimplemented");
+	Assert_SC_true(!"JVM_RegisterContinuationMethods unimplemented");
 }
 
 JNIEXPORT jboolean JNICALL
@@ -254,11 +253,25 @@ JVM_VirtualThreadMountBegin(JNIEnv *env, jobject thread, jboolean firstMount)
 	J9JavaVM *vm = currentThread->javaVM;
 	J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
 
+	Trc_SC_VirtualThreadMountBegin_Entry(currentThread, thread, firstMount);
+
 	vmFuncs->internalEnterVMFromJNI(currentThread);
 	f_monitorEnter(vm->liveVirtualThreadListMutex);
 	j9object_t threadObj = J9_JNI_UNWRAP_REFERENCE(thread);
 
-	assert(IS_JAVA_LANG_VIRTUALTHREAD(currentThread, threadObj));
+	Assert_SC_true(IS_JAVA_LANG_VIRTUALTHREAD(currentThread, threadObj));
+
+	if (TrcEnabled_Trc_SC_VirtualThread_Info) {
+		j9object_t continuationObj = J9VMJAVALANGVIRTUALTHREAD_CONT(currentThread, threadObj);
+		Trc_SC_VirtualThread_Info(
+				currentThread,
+				threadObj,
+				J9VMJAVALANGVIRTUALTHREAD_STATE(currentThread, threadObj),
+				J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset),
+				J9VMJAVALANGVIRTUALTHREAD_CARRIERTHREAD(currentThread, threadObj),
+				continuationObj,
+				J9VMJDKINTERNALVMCONTINUATION_VMREF(currentThread, continuationObj));
+	}
 
 	while (vm->inspectingLiveVirtualThreadList
 	|| (0 != J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset))
@@ -282,6 +295,8 @@ JVM_VirtualThreadMountBegin(JNIEnv *env, jobject thread, jboolean firstMount)
 
 	f_monitorExit(vm->liveVirtualThreadListMutex);
 	vmFuncs->internalExitVMToJNI(currentThread);
+
+	Trc_SC_VirtualThreadMountBegin_Exit(currentThread, thread, firstMount);
 }
 
 JNIEXPORT void JNICALL
@@ -291,10 +306,24 @@ JVM_VirtualThreadMountEnd(JNIEnv *env, jobject thread, jboolean firstMount)
 	J9JavaVM *vm = currentThread->javaVM;
 	J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
 
+	Trc_SC_VirtualThreadMountEnd_Entry(currentThread, thread, firstMount);
+
 	vmFuncs->internalEnterVMFromJNI(currentThread);
 	f_monitorEnter(vm->liveVirtualThreadListMutex);
 	j9object_t threadObj = J9_JNI_UNWRAP_REFERENCE(thread);
 
+	if (TrcEnabled_Trc_SC_VirtualThread_Info) {
+		j9object_t continuationObj = J9VMJAVALANGVIRTUALTHREAD_CONT(currentThread, threadObj);
+		Trc_SC_VirtualThread_Info(
+				currentThread,
+				threadObj,
+				J9VMJAVALANGVIRTUALTHREAD_STATE(currentThread, threadObj),
+				J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset),
+				J9VMJAVALANGVIRTUALTHREAD_CARRIERTHREAD(currentThread, threadObj),
+				continuationObj,
+				J9VMJDKINTERNALVMCONTINUATION_VMREF(currentThread, continuationObj));
+	}
+
 	if (firstMount) {
 		if (NULL == vm->liveVirtualThreadList) {
 			J9Class *virtualThreadClass = J9OBJECT_CLAZZ(currentThread, J9_JNI_UNWRAP_REFERENCE(thread));
@@ -322,6 +351,14 @@ JVM_VirtualThreadMountEnd(JNIEnv *env, jobject thread, jboolean firstMount)
 		}
 
 		if (NULL != vm->liveVirtualThreadList) {
+			j9object_t threadPrev = J9OBJECT_OBJECT_LOAD(currentThread, threadObj, vm->virtualThreadLinkPreviousOffset);
+			j9object_t threadNext = J9OBJECT_OBJECT_LOAD(currentThread, threadObj, vm->virtualThreadLinkNextOffset);
+
+			/* Non-null previous and next elements in the list suggest that the thread has
+			 * already been added to the list. Only add to the list if the previous and
+			 * next elements in the list are null.
+			 */
+			Assert_SC_true((NULL == threadPrev) && (NULL == threadNext));
 			j9object_t root = *(vm->liveVirtualThreadList);
 			j9object_t rootPrev = J9OBJECT_OBJECT_LOAD(currentThread, root, vm->virtualThreadLinkPreviousOffset);
 
@@ -336,7 +373,7 @@ JVM_VirtualThreadMountEnd(JNIEnv *env, jobject thread, jboolean firstMount)
 	}
 
 	/* Allow thread to be inspected again. */
-	assert(-1 == J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset));
+	Assert_SC_true(-1 == J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset));
 	J9OBJECT_I64_STORE(currentThread, threadObj, vm->virtualThreadInspectorCountOffset, 0);
 
 	/* If isSuspendedByJVMTI is non-zero, J9_PUBLIC_FLAGS_HALT_THREAD_JAVA_SUSPEND is set
@@ -352,6 +389,8 @@ JVM_VirtualThreadMountEnd(JNIEnv *env, jobject thread, jboolean firstMount)
 	f_monitorExit(vm->liveVirtualThreadListMutex);
 
 	vmFuncs->internalExitVMToJNI(currentThread);
+
+	Trc_SC_VirtualThreadMountEnd_Exit(currentThread, thread, firstMount);
 }
 
 JNIEXPORT void JNICALL
@@ -361,10 +400,24 @@ JVM_VirtualThreadUnmountBegin(JNIEnv *env, jobject thread, jboolean lastUnmount)
 	J9JavaVM *vm = currentThread->javaVM;
 	J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
 
+	Trc_SC_VirtualThreadUnmountBegin_Entry(currentThread, thread, lastUnmount);
+
 	vmFuncs->internalEnterVMFromJNI(currentThread);
 	f_monitorEnter(vm->liveVirtualThreadListMutex);
 	j9object_t threadObj = J9_JNI_UNWRAP_REFERENCE(thread);
 
+	if (TrcEnabled_Trc_SC_VirtualThread_Info) {
+		j9object_t continuationObj = J9VMJAVALANGVIRTUALTHREAD_CONT(currentThread, threadObj);
+		Trc_SC_VirtualThread_Info(
+				currentThread,
+				threadObj,
+				J9VMJAVALANGVIRTUALTHREAD_STATE(currentThread, threadObj),
+				J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset),
+				J9VMJAVALANGVIRTUALTHREAD_CARRIERTHREAD(currentThread, threadObj),
+				continuationObj,
+				J9VMJDKINTERNALVMCONTINUATION_VMREF(currentThread, continuationObj));
+	}
+
 	while (vm->inspectingLiveVirtualThreadList
 	|| (0 != J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset))
 	) {
@@ -390,16 +443,27 @@ JVM_VirtualThreadUnmountBegin(JNIEnv *env, jobject thread, jboolean lastUnmount)
 			j9object_t threadPrev = J9OBJECT_OBJECT_LOAD(currentThread, threadObj, vm->virtualThreadLinkPreviousOffset);
 			j9object_t threadNext = J9OBJECT_OBJECT_LOAD(currentThread, threadObj, vm->virtualThreadLinkNextOffset);
 
-			/* Remove thread from list. The root will never be removed. */
+			/* Non-null previous and next elements in the list suggest that the thread has
+			 * been added to the list. Only remove from the list if the previous and next
+			 * elements in the list are non-null.
+			 */
+			Assert_SC_true((NULL != threadPrev) && (NULL != threadNext));
+			/* Remove thread from the list. The root will never be removed. */
 			J9OBJECT_OBJECT_STORE(currentThread, threadPrev, vm->virtualThreadLinkNextOffset, threadNext);
 			J9OBJECT_OBJECT_STORE(currentThread, threadNext, vm->virtualThreadLinkPreviousOffset, threadPrev);
+
+			/* Reset previous and next fields in the thread object to null. */
+			J9OBJECT_OBJECT_STORE(currentThread, threadObj, vm->virtualThreadLinkNextOffset, NULL);
+			J9OBJECT_OBJECT_STORE(currentThread, threadObj, vm->virtualThreadLinkPreviousOffset, NULL);
 		}
 
 		TRIGGER_J9HOOK_VM_VIRTUAL_THREAD_END(vm->hookInterface, currentThread);
 	}
 
 	f_monitorExit(vm->liveVirtualThreadListMutex);
 	vmFuncs->internalExitVMToJNI(currentThread);
+
+	Trc_SC_VirtualThreadUnmountBegin_Exit(currentThread, thread, lastUnmount);
 }
 
 JNIEXPORT void JNICALL
@@ -409,10 +473,24 @@ JVM_VirtualThreadUnmountEnd(JNIEnv *env, jobject thread, jboolean lastUnmount)
 	J9JavaVM *vm = currentThread->javaVM;
 	J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
 
+	Trc_SC_VirtualThreadUnmountEnd_Entry(currentThread, thread, lastUnmount);
+
 	vmFuncs->internalEnterVMFromJNI(currentThread);
 	f_monitorEnter(vm->liveVirtualThreadListMutex);
 	j9object_t threadObj = J9_JNI_UNWRAP_REFERENCE(thread);
 
+	if (TrcEnabled_Trc_SC_VirtualThread_Info) {
+		j9object_t continuationObj = J9VMJAVALANGVIRTUALTHREAD_CONT(currentThread, threadObj);
+		Trc_SC_VirtualThread_Info(
+				currentThread,
+				threadObj,
+				J9VMJAVALANGVIRTUALTHREAD_STATE(currentThread, threadObj),
+				J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset),
+				J9VMJAVALANGVIRTUALTHREAD_CARRIERTHREAD(currentThread, threadObj),
+				continuationObj,
+				J9VMJDKINTERNALVMCONTINUATION_VMREF(currentThread, continuationObj));
+	}
+
 	if (lastUnmount) {
 		vmFuncs->freeTLS(currentThread, threadObj);
 		/* CleanupContinuation */
@@ -421,12 +499,14 @@ JVM_VirtualThreadUnmountEnd(JNIEnv *env, jobject thread, jboolean lastUnmount)
 	}
 
 	/* Allow thread to be inspected again. */
-	assert(-1 == J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset));
+	Assert_SC_true(-1 == J9OBJECT_I64_LOAD(currentThread, threadObj, vm->virtualThreadInspectorCountOffset));
 	J9OBJECT_I64_STORE(currentThread, threadObj, vm->virtualThreadInspectorCountOffset, 0);
 	f_monitorNotifyAll(vm->liveVirtualThreadListMutex);
 
 	f_monitorExit(vm->liveVirtualThreadListMutex);
 	vmFuncs->internalExitVMToJNI(currentThread);
+
+	Trc_SC_VirtualThreadUnmountEnd_Exit(currentThread, thread, lastUnmount);
 }
 #endif /* JAVA_SPEC_VERSION >= 19 */