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Update jvmtiHeapFollowRefs_getStackData to handle virtual threads
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Unmounted virtual threads cannot have have a JNI frame. JNI_LOCAL
requests should be ignored for unmounted virtual threads.

STACK_LOCAL requests use 0 for TID since it is not currently feasible
to derive this information for unmounted virtual threads.

Related: #17712

Signed-off-by: Babneet Singh <sbabneet@ca.ibm.com>
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@babsingh
babsingh committed Aug 25, 2023
1 parent 1d0d0a6 commit 1af23c8
Showing 1 changed file with 64 additions and 64 deletions.
128 changes: 64 additions & 64 deletions runtime/jvmti/jvmtiHeap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -118,7 +118,7 @@ static jvmtiError getArrayPrimitiveElements(J9JVMTIHeapData * iteratorData, jvmt
static jvmtiIterationControl followReferencesCallback(j9object_t * slotPtr, j9object_t referrer, void *userData, IDATA type, IDATA referrerIndex, IDATA wasReportedBefore);
static void mapEventType(J9JVMTIHeapData * data, IDATA type, jint index, j9object_t referrer, j9object_t object);
static void jvmtiFollowRefs_getTags(J9JVMTIHeapData * iteratorData, j9object_t referrer, j9object_t object);
static UDATA jvmtiHeapFollowRefs_getStackData(J9JVMTIHeapData * iteratorData, J9StackWalkState *walkState);
static BOOLEAN jvmtiHeapFollowRefs_getStackData(J9JVMTIHeapData *iteratorData, J9StackWalkState *walkState);
static IDATA heapReferenceFilter(J9JVMTIHeapData * iteratorData);


Expand Down Expand Up @@ -756,7 +756,7 @@ wrap_heapReferenceCallback(J9JavaVM * vm, J9JVMTIHeapData * iteratorData)
case JVMTI_HEAP_REFERENCE_JNI_LOCAL:
if (iteratorData->referrer) {
/* fill in the stack local and jni local data */
if (jvmtiHeapFollowRefs_getStackData(iteratorData, (J9StackWalkState *) iteratorData->referrer) == 0)
if (jvmtiHeapFollowRefs_getStackData(iteratorData, (J9StackWalkState *)iteratorData->referrer))
return JVMTI_ITERATION_IGNORE;
} else {
/* No reference info available for heap roots, slime some bogus values
Expand Down Expand Up @@ -830,91 +830,91 @@ wrap_heapReferenceCallback(J9JavaVM * vm, J9JVMTIHeapData * iteratorData)


/**
* \brief Obtain callback data required for JNI or Stack Local references
* \ingroup jvmti.heap
* \brief Obtain callback data required for JNI or Stack Local references
* \ingroup jvmti.heap
*
* @param[in] iteratorData iteration structure containing misc data
* @param[in] e helper structure containing reference details
* @param[in] walkState stack walker structure for the frame containing the reference
* @return none
*
* @param[in] iteratorData iteration structure containing misc data
* @param[in] e helper structure containing reference details
* @param[in] walkState stack walker structure for the frame containing the reference
* @return TRUE to ignore, otherwise FALSE
*/
static UDATA
jvmtiHeapFollowRefs_getStackData(J9JVMTIHeapData * iteratorData, J9StackWalkState *walkState)
static BOOLEAN
jvmtiHeapFollowRefs_getStackData(J9JVMTIHeapData *iteratorData, J9StackWalkState *walkState)
{
J9JVMTIHeapEvent * e = &iteratorData->event;
jint slot = (jint) walkState->slotIndex;
jint depth = (jint) walkState->framesWalked;
J9Method * ramMethod = walkState->method;
jmethodID method;
J9JVMTIObjectTag search;
J9JVMTIObjectTag * result;
jlong threadID;

J9JVMTIHeapEvent *e = &iteratorData->event;
jint slot = (jint)walkState->slotIndex;
jint depth = (jint)walkState->framesWalked;
J9Method *ramMethod = walkState->method;
jmethodID method = NULL;
J9JVMTIObjectTag search = {0};
J9JVMTIObjectTag *result = NULL;
jlong threadID = 0;
J9VMThread *currentThread = iteratorData->currentThread;
j9object_t threadObject = walkState->walkThread->threadObject;
BOOLEAN ignore = TRUE;

/* Convert internal slot type to JVMTI type */
switch (walkState->slotType) {
case J9_STACKWALK_SLOT_TYPE_JNI_LOCAL:
e->refKind = JVMTI_HEAP_REFERENCE_JNI_LOCAL;
break;
case J9_STACKWALK_SLOT_TYPE_METHOD_LOCAL:
e->refKind = JVMTI_HEAP_REFERENCE_STACK_LOCAL;
break;
default:
/* Do not callback with stack slot types other then JNI or STACK Local */
return 0;
case J9_STACKWALK_SLOT_TYPE_JNI_LOCAL:
e->refKind = JVMTI_HEAP_REFERENCE_JNI_LOCAL;
if (NULL == threadObject) {
/* Ignore unmounted virtual threads since they cannot have a JNI frame */
goto done;
}
break;
case J9_STACKWALK_SLOT_TYPE_METHOD_LOCAL:
e->refKind = JVMTI_HEAP_REFERENCE_STACK_LOCAL;
break;
default:
/* Do not callback with stack slot types other then JNI or STACK Local */
goto done;
}

/* If there's no method, set slot, method and depth to -1 */

if (ramMethod == NULL) {
if (NULL == ramMethod) {
slot = -1;
depth = -1;
method = (jmethodID) -1;
method = (jmethodID)-1;
} else {
/* Cheating here - should be current thread, but the walk thread will do */
method = getCurrentMethodID(walkState->walkThread, ramMethod);
method = getCurrentMethodID(currentThread, ramMethod);
if (method == NULL) {
slot = -1;
depth = -1;
method = (jmethodID) -1;
method = (jmethodID)-1;
}
}

/* Find thread tag */

search.ref = (j9object_t ) walkState->walkThread->threadObject;
result = hashTableFind(iteratorData->env->objectTagTable, &search);
if (NULL != threadObject) {
/* Find thread tag */
search.ref = (j9object_t )threadObject;
result = hashTableFind(iteratorData->env->objectTagTable, &search);

/* Figure out the Thread ID */

threadID = J9VMJAVALANGTHREAD_TID(iteratorData->currentThread, walkState->walkThread->threadObject);

/* Figure out the Thread ID */
threadID = J9VMJAVALANGTHREAD_TID(currentThread, threadObject);
}

switch (e->refKind) {
case JVMTI_HEAP_REFERENCE_STACK_LOCAL:
e->refInfo.stack_local.thread_tag = (result) ? result->tag : 0;
e->refInfo.stack_local.thread_id = threadID;
e->refInfo.stack_local.depth = depth;
e->refInfo.stack_local.method = method;
e->refInfo.stack_local.location = (jlocation) walkState->bytecodePCOffset;
e->refInfo.stack_local.slot = slot;
break;

case JVMTI_HEAP_REFERENCE_JNI_LOCAL:

e->refInfo.jni_local.thread_tag = (result) ? result->tag : 0;
e->refInfo.jni_local.thread_id = threadID;
e->refInfo.jni_local.depth = depth;
e->refInfo.jni_local.method = method;
break;

default:
break;
case JVMTI_HEAP_REFERENCE_STACK_LOCAL:
e->refInfo.stack_local.thread_tag = (NULL != result) ? result->tag : 0;
e->refInfo.stack_local.thread_id = threadID;
e->refInfo.stack_local.depth = depth;
e->refInfo.stack_local.method = method;
e->refInfo.stack_local.location = (jlocation) walkState->bytecodePCOffset;
e->refInfo.stack_local.slot = slot;
break;
case JVMTI_HEAP_REFERENCE_JNI_LOCAL:
e->refInfo.jni_local.thread_tag = (NULL != result) ? result->tag : 0;
e->refInfo.jni_local.thread_id = threadID;
e->refInfo.jni_local.depth = depth;
e->refInfo.jni_local.method = method;
break;
default:
break;
}


return 1;
ignore = FALSE;
done:
return ignore;
}


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