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Do not cache nesthost of hidden nestmate classes if extension enabled
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Hidden nest member is not in the nestmember attribute of the nest host.
If extensions are enabled and the nest host is redefined, the nest host
of hidden nest member is not updated. Do not cache nest host into
class->nestHost in this case so that the nest host will always be found
in the class table for hidden nest members.

Signed-off-by: Hang Shao <[email protected]>
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@hangshao0
hangshao0 committed Jul 27, 2023
1 parent ecfd805 commit bac839b
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Showing 7 changed files with 88 additions and 52 deletions.
15 changes: 10 additions & 5 deletions runtime/codert_vm/cnathelp.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3204,6 +3204,8 @@ old_slow_jitNewInstanceImplAccessCheck(J9VMThread *currentThread)
J9InternalVMFunctions *vmFuncs = currentThread->javaVM->internalVMFunctions;
void *oldPC = buildJITResolveFrame(currentThread, J9_SSF_JIT_RESOLVE_RUNTIME_HELPER, parmCount);
IDATA checkResult = vmFuncs->checkVisibility(currentThread, callerClass, thisClass, thisClass->romClass->modifiers, J9_LOOK_REFLECT_CALL);
thisClass = VM_VMHelpers::currentClass(thisClass);
callerClass = VM_VMHelpers::currentClass(callerClass);
if (checkResult < J9_VISIBILITY_ALLOWED) {
illegalAccess:
if (VM_VMHelpers::immediateAsyncPending(currentThread)) {
Expand Down Expand Up @@ -3240,17 +3242,20 @@ old_slow_jitNewInstanceImplAccessCheck(J9VMThread *currentThread)
* unless the two classes are in the same nest (JDK11 and beyond).
*/
#if JAVA_SPEC_VERSION >= 11
if (NULL == thisClass->nestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, thisClass, 0)) {
J9Class *thisClassNestHost = thisClass->nestHost;
J9Class *callerClassNestHost = NULL;
if (NULL == thisClassNestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, thisClass, 0, &thisClassNestHost)) {
goto illegalAccess;
}
}
if (NULL == callerClass->nestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, callerClass, 0)) {
callerClassNestHost = callerClass->nestHost;
if (NULL == callerClassNestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, callerClass, 0, &callerClassNestHost)) {
goto illegalAccess;
}
}
if (thisClass->nestHost != callerClass->nestHost)
if (thisClassNestHost != callerClassNestHost)
#endif /* JAVA_SPEC_VERSION >= 11 */
{
if (thisClass != callerClass) {
Expand Down
14 changes: 8 additions & 6 deletions runtime/j9vm/java11vmi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1613,20 +1613,22 @@ JVM_AreNestMates(JNIEnv *env, jclass jClassOne, jclass jClassTwo)
} else {
J9Class *clazzOne = J9VM_J9CLASS_FROM_HEAPCLASS(currentThread, clazzObjectOne);
J9Class *clazzTwo = J9VM_J9CLASS_FROM_HEAPCLASS(currentThread, clazzObjectTwo);
J9Class *clazzOneNestHost = clazzOne->nestHost;
J9Class *clazzTwoNestHost = NULL;

if (NULL == clazzOne->nestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, clazzOne, J9_LOOK_NO_THROW)) {
if (NULL == clazzOneNestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, clazzOne, J9_LOOK_NO_THROW, &clazzOneNestHost)) {
goto done;
}
}

if (NULL == clazzTwo->nestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, clazzTwo, J9_LOOK_NO_THROW)) {
clazzTwoNestHost = clazzTwo->nestHost;
if (NULL == clazzTwoNestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, clazzTwo, J9_LOOK_NO_THROW, &clazzTwoNestHost)) {
goto done;
}
}

if (clazzOne->nestHost == clazzTwo->nestHost) {
if (clazzOneNestHost == clazzTwoNestHost) {
result = JNI_TRUE;
}
}
Expand Down
17 changes: 8 additions & 9 deletions runtime/jcl/common/java_lang_Class.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1836,9 +1836,7 @@ Java_java_lang_Class_getNestHostImpl(JNIEnv *env, jobject recv)
J9Class *nestHost = clazz->nestHost;

if (NULL == nestHost) {
if (J9_VISIBILITY_ALLOWED == vmFuncs->loadAndVerifyNestHost(currentThread, clazz, J9_LOOK_NO_THROW)) {
nestHost = clazz->nestHost;
} else {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, clazz, J9_LOOK_NO_THROW, &nestHost)) {
/* If there is a failure loading or accessing the nest host, or if this class or interface does
* not specify a nest, then it is considered to belong to its own nest and this is returned as
* the host */
Expand Down Expand Up @@ -1882,10 +1880,9 @@ Java_java_lang_Class_getNestMembersImpl(JNIEnv *env, jobject recv)
J9Class *nestHost = clazz->nestHost;

if (NULL == nestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, clazz, 0)) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, clazz, 0, &nestHost)) {
goto _done;
}
nestHost = clazz->nestHost;
}
romHostClass = nestHost->romClass;
nestMemberCount = romHostClass->nestMemberCount;
Expand Down Expand Up @@ -1920,18 +1917,20 @@ Java_java_lang_Class_getNestMembersImpl(JNIEnv *env, jobject recv)
PUSH_OBJECT_IN_SPECIAL_FRAME(currentThread, resultObject);
J9Class *nestMember = vmFuncs->internalFindClassUTF8(currentThread, J9UTF8_DATA(nestMemberName), J9UTF8_LENGTH(nestMemberName), classLoader, J9_FINDCLASS_FLAG_THROW_ON_FAIL);
resultObject = POP_OBJECT_IN_SPECIAL_FRAME(currentThread);

if (NULL == nestMember) {
/* If internalFindClassUTF8 fails to find the nest member, it sets
* a NoClassDefFoundError
*/
goto _done;
} else if (NULL == nestMember->nestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, nestMember, 0)) {
}
nestMember = VM_VMHelpers::currentClass(nestMember);
J9Class *memberNestHost = nestMember->nestHost;
if (NULL == memberNestHost) {
if (J9_VISIBILITY_ALLOWED != vmFuncs->loadAndVerifyNestHost(currentThread, nestMember, 0, &memberNestHost)) {
goto _done;
}
}
if (nestMember->nestHost != nestHost) {
if (memberNestHost != nestHost) {
vmFuncs->setNestmatesError(currentThread, nestMember, nestHost, J9_VISIBILITY_NEST_MEMBER_NOT_CLAIMED_ERROR);
goto _done;
}
Expand Down
2 changes: 1 addition & 1 deletion runtime/oti/j9nonbuilder.h
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Original file line number Diff line number Diff line change
Expand Up @@ -4962,7 +4962,7 @@ typedef struct J9InternalVMFunctions {
void ( *throwNativeOOMError)(JNIEnv *env, U_32 moduleName, U_32 messageNumber);
void ( *throwNewJavaIoIOException)(JNIEnv *env, const char *message);
#if JAVA_SPEC_VERSION >= 11
UDATA ( *loadAndVerifyNestHost)(struct J9VMThread *vmThread, struct J9Class *clazz, UDATA options);
UDATA ( *loadAndVerifyNestHost)(struct J9VMThread *vmThread, struct J9Class *clazz, UDATA options, J9Class **nestHostFound);
void ( *setNestmatesError)(struct J9VMThread *vmThread, struct J9Class *nestMember, struct J9Class *nestHost, IDATA errorCode);
#endif /* JAVA_SPEC_VERSION >= 11 */
BOOLEAN ( *areValueTypesEnabled)(struct J9JavaVM *vm);
Expand Down
9 changes: 5 additions & 4 deletions runtime/oti/vm_api.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3657,16 +3657,17 @@ trace(J9VMThread *vmStruct);
* to the same runtime package as the class. This function requires
* VMAccess
*
* @param vmThread handle to vmThread
* @param clazz the class to search the nest host
* @param options lookup options
* @param[in] vmThread handle to vmThread
* @param[in] clazz the class to search the nest host
* @param[in] options lookup options
* @param[out] nestHostFound the nest host of clazz
*
* @return J9_VISIBILITY_ALLOWED if success,
* J9_VISIBILITY_NEST_HOST_LOADING_FAILURE_ERROR if failed to load nesthost,
* J9_VISIBILITY_NEST_HOST_DIFFERENT_PACKAGE_ERROR if nesthost is not in the same runtime package
*/
UDATA
loadAndVerifyNestHost(J9VMThread *vmThread, J9Class *clazz, UDATA options);
loadAndVerifyNestHost(J9VMThread *vmThread, J9Class *clazz, UDATA options, J9Class **nestHostFound);

/**
* Sets the nestmates error based on the errorCode
Expand Down
4 changes: 3 additions & 1 deletion runtime/vm/j9vm.tdf
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Original file line number Diff line number Diff line change
Expand Up @@ -353,7 +353,7 @@ TraceEvent=Trc_VM_objectMonitorEnterBlocking_gotFlatLockInLoop Overhead=1 Level=
TraceExit=Trc_VM_objectMonitorEnterBlocking_Exit Overhead=1 Level=4 Template="objectMonitorEnterBlocking -- result = %p"

TraceEntry=Trc_VM_checkVisibility_Entry Overhead=1 Level=3 Template="checkVisibility from %p to %p modifiers=%zx"
TraceException=Trc_VM_checkVisibility_Failed Overhead=1 Level=1 Template="checkVisibility from %p (%.*s) to %p (%.*s) modifiers=%zx failed"
TraceException=Trc_VM_checkVisibility_Failed Obsolete Overhead=1 Level=1 Template="checkVisibility from %p (%.*s) to %p (%.*s) modifiers=%zx failed"
TraceExit=Trc_VM_checkVisibility_Exit Overhead=1 Level=3 Template="checkVisibility result=%x"

TraceEntry=Trc_VM_resolveKnownClass_Entry Overhead=1 Level=1 Template="resolveKnownClass(index=%zu)"
Expand Down Expand Up @@ -928,3 +928,5 @@ TraceEvent=Trc_VM_allocateThunkHeap_allocate_thunk_heap_node_failed NoEnv Overhe

TraceExit=Trc_VM_criu_initHooks_Exit Overhead=1 Level=5 Template="initializeCriuHooks - checkpointState.hookRecords (%p), classIterationRestoreHookRecords (%p), delayedLockingOperationsRecords (%p)"
TraceException=Trc_VM_criu_setSingleThreadModeJVMCRIUException_triggerOneOffJavaDump Overhead=1 Level=1 Template="setCRIUSingleThreadModeJVMCRIUException triggerOneOffDump() returns %d"

TraceException=Trc_VM_checkVisibility_Failed Overhead=1 Level=1 Template="checkVisibility from %p (%.*s) to %p (%.*s) modifiers=%zx lookupOptions=%zx failed"
79 changes: 53 additions & 26 deletions runtime/vm/visible.c
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Original file line number Diff line number Diff line change
Expand Up @@ -129,24 +129,26 @@ checkVisibility(J9VMThread *currentThread, J9Class* sourceClass, J9Class* destCl
* host is loaded first and the class being accessed loads its
* nest host after.
*/
if (NULL == sourceClass->nestHost) {
result = loadAndVerifyNestHost(currentThread, sourceClass, lookupOptions);
J9Class *sourceClassNestHost = sourceClass->nestHost;
J9Class *destClassNestHost = NULL;
if (NULL == sourceClassNestHost) {
result = loadAndVerifyNestHost(currentThread, sourceClass, lookupOptions, &sourceClassNestHost);
if (J9_VISIBILITY_ALLOWED != result) {
goto _exit;
}
sourceClass = J9_CURRENT_CLASS(sourceClass);
destClass = J9_CURRENT_CLASS(destClass);
}
if (NULL == destClass->nestHost) {
result = loadAndVerifyNestHost(currentThread, destClass, lookupOptions);
destClassNestHost = destClass->nestHost;
if (NULL == destClassNestHost) {
result = loadAndVerifyNestHost(currentThread, destClass, lookupOptions, &destClassNestHost);
if (J9_VISIBILITY_ALLOWED != result) {
goto _exit;
}
sourceClass = J9_CURRENT_CLASS(sourceClass);
destClass = J9_CURRENT_CLASS(destClass);
}

if (sourceClass->nestHost != destClass->nestHost) {
if (sourceClassNestHost != destClassNestHost) {
result = J9_VISIBILITY_NON_MODULE_ACCESS_ERROR;
}
} else
Expand Down Expand Up @@ -182,11 +184,11 @@ checkVisibility(J9VMThread *currentThread, J9Class* sourceClass, J9Class* destCl
_exit:
#endif /* JAVA_SPEC_VERSION >= 11 */
if (J9_VISIBILITY_NON_MODULE_ACCESS_ERROR == result) {
/* "checkVisibility from %p (%.*s) to %p (%.*s) modifiers=%zx failed" */
/* "checkVisibility from %p (%.*s) to %p (%.*s) modifiers=%zx lookupOptions=%zx failed" */
Trc_VM_checkVisibility_Failed(currentThread,
sourceClass, J9UTF8_LENGTH(J9ROMCLASS_CLASSNAME(sourceClass->romClass)), J9UTF8_DATA(J9ROMCLASS_CLASSNAME(sourceClass->romClass)),
destClass, J9UTF8_LENGTH(J9ROMCLASS_CLASSNAME(destClass->romClass)), J9UTF8_DATA(J9ROMCLASS_CLASSNAME(destClass->romClass)),
modifiers);
modifiers, lookupOptions);
}

Trc_VM_checkVisibility_Exit(currentThread, result);
Expand Down Expand Up @@ -271,29 +273,42 @@ setNestmatesError(J9VMThread *vmThread, J9Class *nestMember, J9Class *nestHost,
/*
* Loads and verifies the nesthost
*
* @param vmThread vmthread token
* @param clazz the j9lass requesting the nesthost
* @param options loading options (e.g. J9_LOOK_NO_THROW)
* @param[in] vmThread vmthread token
* @param[in] clazz the j9lass requesting the nesthost
* @param[in] options loading options (e.g. J9_LOOK_NO_THROW)
* @param[out] nestHostFound the nest host of clazz
* @return J9_VISIBILITY_ALLOWED if nest host is loaded, otherwise
* J9_VISIBILITY_NEST_HOST_LOADING_FAILURE_ERROR
* J9_VISIBILITY_NEST_HOST_DIFFERENT_PACKAGE_ERROR
* J9_VISIBILITY_NEST_MEMBER_NOT_CLAIMED_ERROR
*/
UDATA
loadAndVerifyNestHost(J9VMThread *vmThread, J9Class *clazz, UDATA options)
loadAndVerifyNestHost(J9VMThread *vmThread, J9Class *clazz, UDATA options, J9Class **nestHostFound)
{
UDATA result = J9_VISIBILITY_ALLOWED;
if (NULL == clazz->nestHost) {
J9Class *nestHost = NULL;
J9Class *nestHost = clazz->nestHost;
if (NULL != nestHost) {
*nestHostFound = nestHost;
} else {
J9ROMClass *romClass = clazz->romClass;
J9UTF8 *nestHostName = J9ROMCLASS_NESTHOSTNAME(romClass);
BOOLEAN canRunJavaCode = J9_ARE_NO_BITS_SET(options, J9_LOOK_NO_JAVA);
BOOLEAN throwException = canRunJavaCode && J9_ARE_NO_BITS_SET(options, J9_LOOK_NO_THROW);
BOOLEAN hiddenNestMate = J9ROMCLASS_IS_OPTIONNESTMATE_SET(romClass);
J9Class* curClazz = clazz;
BOOLEAN cacheNestHostInClass = TRUE;
J9Class *curClazz = clazz;

if (hiddenNestMate) {
BOOLEAN isCurClassHiddenNestMate = hiddenNestMate;
if (areExtensionsEnabled(vmThread->javaVM)) {
/*
* Hidden class is not in the nestmember attribute of the nest host. So nest host cannot find hidden class nest members.
* Class redefinition cannot update the nest host of hidden class in fixNestMembers()(hshelp.c).
* So do not set cache nest host in clazz->nestHost, as the host might have been redefined.
* Always using the class name to get the nest host from the class table.
*/
cacheNestHostInClass = FALSE;
}
while ((isCurClassHiddenNestMate)
&& (curClazz != curClazz->hostClass)
) {
Expand All @@ -302,15 +317,21 @@ loadAndVerifyNestHost(J9VMThread *vmThread, J9Class *clazz, UDATA options)
isCurClassHiddenNestMate = J9ROMCLASS_IS_OPTIONNESTMATE_SET(curClazz->romClass);
nestHostName = J9ROMCLASS_NESTHOSTNAME(curClazz->romClass);
}

if (NULL != curClazz->nestHost) {
/*
* hidden class defined with ClassOption.NESTMATE has the same nest host as its hostClass (curClazz).
* The nest host of curClass is already found, return directly.
*/
clazz->nestHost = curClazz->nestHost;
result = J9_VISIBILITY_ALLOWED;
goto done;
if (cacheNestHostInClass) {
if (NULL != curClazz->nestHost) {
/*
* hidden class defined with ClassOption.NESTMATE has the same nest host as its hostClass (curClazz).
* The nest host of curClass is already found, return directly.
*/
*nestHostFound = curClazz->nestHost;
clazz->nestHost = *nestHostFound;
result = J9_VISIBILITY_ALLOWED;
goto done;
}
} else {
if (NULL == nestHostName) {
nestHostName = J9ROMCLASS_CLASSNAME(curClazz->romClass);
}
}
}

Expand Down Expand Up @@ -360,7 +381,10 @@ loadAndVerifyNestHost(J9VMThread *vmThread, J9Class *clazz, UDATA options)

/* If a problem occurred in nest host verification then the nest host value is invalid */
if (J9_VISIBILITY_ALLOWED == result) {
clazz->nestHost = nestHost;
*nestHostFound = nestHost;
if (cacheNestHostInClass) {
clazz->nestHost = nestHost;
}
} else if ((JAVA_SPEC_VERSION >= 15) && canRunJavaCode) {
/**
* JVM spec updated in Java 15:
Expand All @@ -371,7 +395,10 @@ loadAndVerifyNestHost(J9VMThread *vmThread, J9Class *clazz, UDATA options)
* which tries to find the nest host in loaded classes only. It is possible that nest host is not loaded yet.
* So set clazz->nestHost only when canRunJavaCode is TRUE.
*/
clazz->nestHost = curClazz;
*nestHostFound = curClazz;
if (cacheNestHostInClass) {
clazz->nestHost = curClazz;
}
vmThread->currentException = NULL;
vmThread->privateFlags &= ~(UDATA)J9_PRIVATE_FLAGS_REPORT_EXCEPTION_THROW;
result = J9_VISIBILITY_ALLOWED;
Expand Down

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