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jvmtiHeap.c
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/*******************************************************************************
* Copyright (c) 1991, 2018 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
* distribution and is available at https://www.eclipse.org/legal/epl-2.0/
* or the Apache License, Version 2.0 which accompanies this distribution and
* is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* This Source Code may also be made available under the following
* Secondary Licenses when the conditions for such availability set
* forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
* General Public License, version 2 with the GNU Classpath
* Exception [1] and GNU General Public License, version 2 with the
* OpenJDK Assembly Exception [2].
*
* [1] https://www.gnu.org/software/classpath/license.html
* [2] http://openjdk.java.net/legal/assembly-exception.html
*
* 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 "jvmtiHelpers.h"
#include "jvmtinls.h"
#include "j9modron.h"
#include "jvmti_internal.h"
#include "HeapIteratorAPI.h"
#include "j9cp.h"
#include "omrgcconsts.h"
#undef JVMTI_HEAP_DEBUG
typedef struct J9JVMTIObjectTagMatch {
J9JavaVM * vm;
J9VMThread * currentThread;
/* search... */
jint forLen;
const jlong * forTags;
/* results... */
jint count;
jobject * objects;
jlong * tags;
} J9JVMTIObjectTagMatch;
/**
* Helper structure used to obtain referrer and referee tags
*/
typedef struct jvmtiHeapTags {
jlong objectTag;
jlong classTag;
jlong referrerObjectTag;
jlong referrerClassTag;
} jvmtiHeapTags;
typedef enum J9JVMTIHeapEventType {
J9JVMTI_HEAP_EVENT_NONE, /* Do not report a reference, do follow it */
J9JVMTI_HEAP_EVENT_NONE_REPORT_NOFOLLOW, /* Report the reference but do not follow it */
J9JVMTI_HEAP_EVENT_NONE_NOFOLLOW, /* Do not report or follow a reference */
J9JVMTI_HEAP_EVENT_ROOT,
J9JVMTI_HEAP_EVENT_STACK,
J9JVMTI_HEAP_EVENT_OBJECT
} J9JVMTIHeapEventType;
typedef struct J9JVMTIHeapEvent {
IDATA gcType;
J9JVMTIHeapEventType type;
jvmtiHeapReferenceKind refKind;
jvmtiHeapReferenceInfo refInfo;
jboolean hasRefInfo;
} J9JVMTIHeapEvent;
typedef enum J9JVMTIHeapIterationFlags {
J9JVMTI_HI_INITIAL_OBJECT_REF = 1,
} J9JVMTIHeapIterationFlags;
typedef struct J9JVMTIHeapData {
J9JVMTIEnv * env;
J9VMThread * currentThread;
jint filter; /** filter flags specified by the user */
J9Class * classFilter; /** class filter specified by the user */
void * userData; /** private user data to be passed back (to the user) via the callbacks */
J9Class * clazz;
jvmtiError rc; /** jvmti error code */
jvmtiIterationControl visitRc;
J9JVMTIHeapIterationFlags flags; /** private iteration control flags */
J9JVMTIHeapEvent event;
j9object_t referrer; /** The referrer object */
j9object_t object; /** The referee (refered to by referrer) */
jlong objectSize;
jvmtiHeapTags tags;
const jvmtiHeapCallbacks *callbacks;
} J9JVMTIHeapData;
static UDATA copyObjectTags (J9JVMTIObjectTag * entry, J9JVMTIObjectTagMatch * results);
static UDATA countObjectTags (J9JVMTIObjectTag * entry, J9JVMTIObjectTagMatch * results);
static jvmtiIterationControl iterateThroughHeapCallback(J9JavaVM * vm, J9MM_IterateObjectDescriptor *objectDesc, void * userData);
static jvmtiIterationControl wrap_heapReferenceCallback(J9JavaVM * vm, J9JVMTIHeapData * iteratorData);
static jvmtiIterationControl wrap_heapIterationCallback(J9JavaVM * vm, J9JVMTIHeapData * iteratorData);
static jvmtiIterationControl wrap_arrayPrimitiveValueCallback(J9JavaVM * vm, J9JVMTIHeapData * iteratorData);
static jvmtiIterationControl wrap_primitiveFieldCallback(J9JavaVM * vm, J9JVMTIHeapData * iteratorData, IDATA wasReportedBefore);
static jvmtiIterationControl wrap_stringPrimitiveCallback(J9JavaVM * vm, J9JVMTIHeapData * iteratorData);
static void updateObjectTag(J9JVMTIHeapData * iteratorData, j9object_t object, jlong * originalTag, jlong newTag);
static jvmtiPrimitiveType getArrayPrimitiveType(J9VMThread * vmThread, j9object_t object, jlong * primitiveSize);
static jvmtiError getArrayPrimitiveElements(J9JVMTIHeapData * iteratorData, jvmtiPrimitiveType * primitiveType, void **elements, jint elementCount);
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 IDATA heapReferenceFilter(J9JVMTIHeapData * iteratorData);
#ifdef JVMTI_HEAP_DEBUG
static void jvmtiHeapFollowReferencesPrint(J9JavaVM * vm, j9object_t object, j9object_t referrer, J9JVMTIHeapData * iteratorData);
static const char * jvmtiHeapReferenceKindString(jvmtiHeapReferenceKind refKind);
static const char * jvmtiHeapRootKindString(jvmtiHeapRootKind refKind);
#endif
#ifdef JVMTI_HEAP_DEBUG
#define jvmtiHeapFR_printf(args) printf args
#define jvmtiHeapITH_printf(args) printf args
#else
#define jvmtiHeapFR_printf(args)
#define jvmtiHeapITH_printf(args)
#endif
#define JVMTI_HEAP_ERROR(err) \
do { \
iteratorData->rc = (err); \
goto done; \
} while(0)
#define JVMTI_HEAP_CHECK_RC(err) \
do { \
if ((err != JVMTI_ERROR_NONE)) { \
goto done; \
} \
} while(0)
#define JVMTI_HEAP_CHECK_ITERATION_ABORT(rc) \
do { \
if ((rc == JVMTI_ITERATION_ABORT)) { \
goto done; \
} \
} while(0)
jvmtiError JNICALL
jvmtiGetTag(jvmtiEnv* env,
jobject object,
jlong* tag_ptr)
{
J9JavaVM * vm = JAVAVM_FROM_ENV(env);
J9VMThread * currentThread;
jvmtiError rc;
Trc_JVMTI_jvmtiGetTag_Entry(env);
rc = getCurrentVMThread(vm, ¤tThread);
if (rc == JVMTI_ERROR_NONE) {
J9JVMTIObjectTag entry;
J9JVMTIObjectTag * objectTag;
vm->internalVMFunctions->internalEnterVMFromJNI(currentThread);
ENSURE_PHASE_START_OR_LIVE(env);
ENSURE_CAPABILITY(env, can_tag_objects);
ENSURE_JOBJECT_NON_NULL(object);
ENSURE_NON_NULL(tag_ptr);
if (AUTOTAGGING_OBJECTS(env)) {
if ( !J9VM_IS_INITIALIZED_HEAPCLASS(currentThread, (*(j9object_t *)object)) ) {
JVMTI_ERROR(JVMTI_ERROR_INVALID_OBJECT);
}
}
entry.ref = *(j9object_t *)object;
if ( entry.ref ) {
/* Ensure exclusive access to tag table */
omrthread_monitor_enter(((J9JVMTIEnv *)env)->mutex);
objectTag = hashTableFind(((J9JVMTIEnv *)env)->objectTagTable, &entry);
if (objectTag) {
*tag_ptr = objectTag->tag;
} else {
*tag_ptr = 0;
}
omrthread_monitor_exit(((J9JVMTIEnv *)env)->mutex);
} else {
rc = JVMTI_ERROR_INVALID_OBJECT;
}
done:
vm->internalVMFunctions->internalExitVMToJNI(currentThread);
}
TRACE_JVMTI_RETURN(jvmtiGetTag);
}
jvmtiError JNICALL
jvmtiSetTag(jvmtiEnv* env,
jobject object,
jlong tag)
{
J9JavaVM * vm = JAVAVM_FROM_ENV(env);
J9VMThread * currentThread;
jvmtiError rc;
Trc_JVMTI_jvmtiSetTag_Entry(env);
rc = getCurrentVMThread(vm, ¤tThread);
if (rc == JVMTI_ERROR_NONE) {
J9JVMTIObjectTag entry;
J9JVMTIObjectTag * objectTag;
vm->internalVMFunctions->internalEnterVMFromJNI(currentThread);
ENSURE_PHASE_START_OR_LIVE(env);
ENSURE_CAPABILITY(env, can_tag_objects);
ENSURE_JOBJECT_NON_NULL(object);
if (AUTOTAGGING_OBJECTS(env)) {
if ( !J9VM_IS_INITIALIZED_HEAPCLASS(currentThread, (*(j9object_t *)object)) ) {
JVMTI_ERROR(JVMTI_ERROR_INVALID_OBJECT);
}
}
entry.ref = *(j9object_t *)object;
entry.tag = tag;
if ( entry.ref ) {
/* Ensure exclusive access to tag table */
omrthread_monitor_enter(((J9JVMTIEnv *)env)->mutex);
objectTag = hashTableFind(((J9JVMTIEnv *)env)->objectTagTable, &entry);
if (objectTag) {
if (tag) {
objectTag->tag = tag;
} else {
hashTableRemove(((J9JVMTIEnv *)env)->objectTagTable, &entry);
}
} else {
if (tag) {
if ( hashTableAdd(((J9JVMTIEnv *)env)->objectTagTable, &entry) == NULL ) {
rc = JVMTI_ERROR_OUT_OF_MEMORY;
}
}
}
omrthread_monitor_exit(((J9JVMTIEnv *)env)->mutex);
} else {
rc = JVMTI_ERROR_INVALID_OBJECT;
}
done:
vm->internalVMFunctions->internalExitVMToJNI(currentThread);
}
TRACE_JVMTI_RETURN(jvmtiSetTag);
}
jvmtiError JNICALL
jvmtiForceGarbageCollection(jvmtiEnv* env)
{
J9JavaVM * vm = JAVAVM_FROM_ENV(env);
J9VMThread * currentThread;
jvmtiError rc;
Trc_JVMTI_jvmtiForceGarbageCollection_Entry(env);
rc = getCurrentVMThread(vm, ¤tThread);
if (rc == JVMTI_ERROR_NONE) {
/* j9gc_modron_global_collect requires that the current thread has VM access */
vm->internalVMFunctions->internalEnterVMFromJNI(currentThread);
ENSURE_PHASE_LIVE(env);
vm->memoryManagerFunctions->j9gc_modron_global_collect(currentThread);
done:
vm->internalVMFunctions->internalExitVMToJNI(currentThread);
}
TRACE_JVMTI_RETURN(jvmtiForceGarbageCollection);
}
jvmtiError JNICALL
jvmtiGetObjectsWithTags(jvmtiEnv* env,
jint tag_count,
const jlong* tags,
jint* count_ptr,
jobject** object_result_ptr,
jlong** tag_result_ptr)
{
J9JavaVM * vm = JAVAVM_FROM_ENV(env);
J9VMThread * currentThread;
jvmtiError rc;
PORT_ACCESS_FROM_JAVAVM(vm);
Trc_JVMTI_jvmtiGetObjectsWithTags_Entry(env);
rc = getCurrentVMThread(vm, ¤tThread);
if (rc == JVMTI_ERROR_NONE) {
jint i;
J9JVMTIObjectTagMatch results;
vm->internalVMFunctions->internalEnterVMFromJNI(currentThread);
ENSURE_PHASE_LIVE(env);
ENSURE_CAPABILITY(env, can_tag_objects);
ENSURE_NON_NEGATIVE(tag_count);
ENSURE_NON_NULL(tags);
ENSURE_NON_NULL(count_ptr);
if ( tag_count == 0 ) {
*count_ptr = 0;
JVMTI_ERROR(JVMTI_ERROR_NONE);
}
/* Verify supplied tags */
for ( i = 0; i < tag_count; i++ ) {
if ( tags[i] == 0 ) {
JVMTI_ERROR(JVMTI_ERROR_ILLEGAL_ARGUMENT);
}
}
/* Ensure exclusive access to tag table */
omrthread_monitor_enter(((J9JVMTIEnv *)env)->mutex);
memset(&results, 0, sizeof(J9JVMTIObjectTagMatch));
results.vm = vm;
results.currentThread = currentThread;
results.forTags = tags;
results.forLen = tag_count;
hashTableForEachDo(((J9JVMTIEnv *)env)->objectTagTable, (J9HashTableDoFn) countObjectTags, &results);
if (object_result_ptr) {
results.objects = j9mem_allocate_memory(sizeof(jobject) * results.count, J9MEM_CATEGORY_JVMTI_ALLOCATE);
if (results.objects == NULL) {
rc = JVMTI_ERROR_OUT_OF_MEMORY;
}
}
if (tag_result_ptr && rc == JVMTI_ERROR_NONE) {
results.tags = j9mem_allocate_memory(sizeof(jlong) * results.count, J9MEM_CATEGORY_JVMTI_ALLOCATE);
if (results.tags == NULL) {
rc = JVMTI_ERROR_OUT_OF_MEMORY;
}
}
if (rc == JVMTI_ERROR_NONE) {
*count_ptr = results.count;
if (object_result_ptr) {
*object_result_ptr = results.objects;
}
if (tag_result_ptr) {
*tag_result_ptr = results.tags;
}
/* Fill in elements ... unwinds results.count */
if (object_result_ptr || tag_result_ptr) {
hashTableForEachDo(((J9JVMTIEnv *)env)->objectTagTable, (J9HashTableDoFn) copyObjectTags, &results);
}
} else {
/* Failure: clean up any allocs */
j9mem_free_memory(results.objects);
j9mem_free_memory(results.tags);
}
omrthread_monitor_exit(((J9JVMTIEnv *)env)->mutex);
done:
vm->internalVMFunctions->internalExitVMToJNI(currentThread);
}
TRACE_JVMTI_RETURN(jvmtiGetObjectsWithTags);
}
static UDATA
copyObjectTags(J9JVMTIObjectTag * entry, J9JVMTIObjectTagMatch * results)
{
J9JavaVM * vm = results->vm;
JNIEnv * jniEnv = (JNIEnv *)results->currentThread;
int i;
for ( i = 0; i < results->forLen; i++ ) {
if ( results->forTags[i] == entry->tag ) {
jint slot = results->count - 1;
/* Reverse fill */
if (results->objects) {
results->objects[slot] = (jobject) vm->internalVMFunctions->j9jni_createLocalRef( jniEnv, entry->ref );
}
if (results->tags) {
results->tags[slot] = entry->tag;
}
results->count = slot;
break;
}
}
return 0;
}
static UDATA
countObjectTags(J9JVMTIObjectTag * entry, J9JVMTIObjectTagMatch * results)
{
int i;
for ( i = 0; i < results->forLen; i++ ) {
if ( results->forTags[i] == entry->tag ) {
results->count++;
break;
}
}
return 0;
}
/**
* \brief Follow References starting at <code>initial_object</code> or Heap Roots
* \ingroup jvmti.heap
*
* @param env jvmti environment
* @param heap_filter tag filter flags used to determine which objects are to be reported
* @param klass class filter
* @param initial_object object to start following the references from. Set to null to start witht the Heap Roots
* @param callbacks callbacks to be invoked for each reference type
* @param user_data user data to be passed back via the callbacks
* @return a jvmtiError value
*
* Full spec is available here: http://j9.ottawa.ibm.com/j9dt/specs/jvmti.html#FollowReferences
*/
jvmtiError JNICALL
jvmtiFollowReferences(jvmtiEnv* env, jint heap_filter, jclass klass, jobject initial_object, const jvmtiHeapCallbacks* callbacks,
const void* user_data)
{
J9JavaVM * vm = JAVAVM_FROM_ENV(env);
J9VMThread * currentThread;
jvmtiError rc;
Trc_JVMTI_jvmtiFollowReferences_Entry(env);
rc = getCurrentVMThread(vm, ¤tThread);
if (rc == JVMTI_ERROR_NONE) {
J9JVMTIHeapData iteratorData;
memset(&iteratorData, 0x00, sizeof(J9JVMTIHeapData));
vm->internalVMFunctions->internalEnterVMFromJNI(currentThread);
ENSURE_PHASE_LIVE(env);
ENSURE_CAPABILITY(env, can_tag_objects);
/* heap_filter is a bitfield - JDK allows undefined bits to be declared, so no checking is needed for it */
ENSURE_NON_NULL(callbacks);
iteratorData.env = (J9JVMTIEnv *) env;
iteratorData.currentThread = currentThread;
iteratorData.filter = heap_filter;
iteratorData.classFilter = klass ? J9VM_J9CLASS_FROM_JCLASS(currentThread, klass) : NULL;
iteratorData.callbacks = callbacks;
iteratorData.userData = (void *) user_data;
iteratorData.clazz = 0;
iteratorData.rc = JVMTI_ERROR_NONE;
/* Do not report anything if the class filter set by the user is an interface class. Quote from the spec:
* "If klass is an interface, no objects are reported. This applies to both the object and primitive callbacks."
* iteratorData->classFilter is klass in this case. Checked against SUN behaviour to verify.
* Don't even start iteration as there will never be any callbacks issued. */
if (iteratorData.classFilter && (iteratorData.classFilter->romClass->modifiers & J9AccInterface)) {
goto done;
}
vm->internalVMFunctions->acquireExclusiveVMAccess(currentThread);
/* Walk the heap */
if (initial_object) {
j9object_t object = *(j9object_t *) initial_object;
iteratorData.flags |= J9JVMTI_HI_INITIAL_OBJECT_REF;
/* Call the callback with the initial object. The GC Reference Chain Walker
* does not call us back with the initial object. */
followReferencesCallback(&object, NULL, &iteratorData, J9GC_REFERENCE_TYPE_FIELD , 0, 0);
vm->memoryManagerFunctions->j9gc_ext_reachable_from_object_do(
currentThread, object, followReferencesCallback, &iteratorData, J9_MU_WALK_PREINDEX_INTERFACE_FIELDS);
} else {
vm->memoryManagerFunctions->j9gc_ext_reachable_objects_do(
currentThread, followReferencesCallback, &iteratorData, J9_MU_WALK_OBJECT_BASE |
J9_MU_WALK_SKIP_JVMTI_TAG_TABLES | J9_MU_WALK_PREINDEX_INTERFACE_FIELDS);
}
if (iteratorData.rc != JVMTI_ERROR_NONE) {
rc = iteratorData.rc;
}
vm->internalVMFunctions->releaseExclusiveVMAccess(currentThread);
done:
vm->internalVMFunctions->internalExitVMToJNI(currentThread);
}
TRACE_JVMTI_RETURN(jvmtiFollowReferences);
}
/**
* \brief Internal callback invoked by the GC RootScanner to process object references
* \ingroup jvmti.heap
*
* @param[in] slotPtr Referee objected referred to by the referrer
* @param[in] referrer Referer object
* @param[in] userData Private user data set by the caller of <code>jvmtiFollowReferences<code>
* @param[in] type Reference type
* @param[in] referrerIndex Index of the referee in the referrer object
* @return
*
* The following object references are reported when they are non-null:
*
* * Instance objects report references to each non-primitive instance fields (including inherited fields).
* * Instance objects report a reference to the object type (class).
* * Classes report a reference to the superclass and directly implemented/extended interfaces.
* * Classes report a reference to the class loader, protection domain, signers, and resolved entries in the constant pool.
* * Classes report a reference to each directly declared non-primitive static field.
* * Arrays report a reference to the array type (class) and each array element.
* * Primitive arrays report a reference to the array type.
*
*/
static jvmtiIterationControl
followReferencesCallback(j9object_t *slotPtr, j9object_t referrer, void *userData, IDATA type, IDATA referrerIndex, IDATA wasReportedBefore)
{
J9JVMTIHeapData * iteratorData = userData;
J9JavaVM *vm = JAVAVM_FROM_ENV(iteratorData->env);
J9VMThread *vmThread = iteratorData->currentThread;
jvmtiIterationControl visitRc = JVMTI_ITERATION_ABORT;
UDATA reportHeapReference = TRUE;
j9object_t object = *slotPtr;
J9Class *clazz;
IDATA filterResult;
/* Do not report uninitialized classes */
if (J9VM_IS_UNINITIALIZED_HEAPCLASS(vmThread, object)) {
return JVMTI_ITERATION_IGNORE;
}
iteratorData->object = object;
iteratorData->referrer = referrer;
/* Map GC event types to JVMTI types */
mapEventType(iteratorData, type, (jint)referrerIndex, referrer, object);
if (iteratorData->event.type == J9JVMTI_HEAP_EVENT_NONE) {
return JVMTI_ITERATION_CONTINUE;
}
if (iteratorData->event.type == J9JVMTI_HEAP_EVENT_NONE_NOFOLLOW) {
return JVMTI_ITERATION_IGNORE;
}
clazz = J9OBJECT_CLAZZ(vmThread, iteratorData->object);
iteratorData->clazz = clazz;
/* Get the 4 tags required by the call back */
jvmtiFollowRefs_getTags(iteratorData, iteratorData->referrer, iteratorData->object);
/* Run it past the iteration control filter */
filterResult = heapReferenceFilter(iteratorData);
if (filterResult >= 0) {
return filterResult;
}
iteratorData->objectSize = getObjectSize(vm, iteratorData->object);
if (iteratorData->flags & J9JVMTI_HI_INITIAL_OBJECT_REF) {
reportHeapReference = FALSE;
}
/* The user might not have set the heap ref callback */
if (iteratorData->callbacks->heap_reference_callback && reportHeapReference == TRUE) {
visitRc = wrap_heapReferenceCallback(vm, iteratorData);
JVMTI_HEAP_CHECK_RC(iteratorData->rc);
JVMTI_HEAP_CHECK_ITERATION_ABORT(visitRc);
}
#ifdef JVMTI_HEAP_DEBUG
jvmtiHeapFollowReferencesPrint(vm, iteratorData->object, iteratorData->referrer, iteratorData);
#endif
/* Is this an Array Object? If so then issue a user callback and pass along the array primitive elements */
if (iteratorData->callbacks->array_primitive_value_callback &&
J9ROMCLASS_IS_PRIMITIVE_OR_ARRAY(clazz->romClass)) {
visitRc = wrap_arrayPrimitiveValueCallback(vm, iteratorData);
JVMTI_HEAP_CHECK_RC(iteratorData->rc);
JVMTI_HEAP_CHECK_ITERATION_ABORT(visitRc);
}
/* Callback for all primitive fields of this object */
if (iteratorData->callbacks->primitive_field_callback) {
visitRc = wrap_primitiveFieldCallback(vm, iteratorData, wasReportedBefore);
JVMTI_HEAP_CHECK_RC(iteratorData->rc);
JVMTI_HEAP_CHECK_ITERATION_ABORT(visitRc);
}
/* TODO: There has got to be a better way of checking if an object is a String or not */
if (iteratorData->callbacks->string_primitive_value_callback) {
J9UTF8 *clazzName = J9ROMCLASS_CLASSNAME(clazz->romClass);
if (J9UTF8_LENGTH(clazzName) == 16 && !memcmp(J9UTF8_DATA(clazzName), "java/lang/String", 16)) {
visitRc = wrap_stringPrimitiveCallback(vm, iteratorData);
JVMTI_HEAP_CHECK_RC(iteratorData->rc);
JVMTI_HEAP_CHECK_ITERATION_ABORT(visitRc);
}
}
/* reset the initial object flag if we've reported its primitive fields, arrays and string values */
if (reportHeapReference == FALSE) {
iteratorData->flags &= ~J9JVMTI_HI_INITIAL_OBJECT_REF;
}
if (iteratorData->event.type == J9JVMTI_HEAP_EVENT_NONE_REPORT_NOFOLLOW) {
return JVMTI_ITERATION_IGNORE;
}
return JVMTI_ITERATION_CONTINUE;
done:
return JVMTI_ITERATION_ABORT;
}
/**
* \brief Filter for heap reference walking
* \ingroup
*
* @param[in] iteratorData
* @return modron heap following control type
*
* Figure out whether a heap reference should be followed based on the class filter
* or tags set by the user.
*/
static IDATA
heapReferenceFilter(J9JVMTIHeapData * iteratorData)
{
/* If the class filter is set, check if this reference is what we are looking for,
* otherwise continue itterating */
if ((iteratorData->classFilter != NULL) && (iteratorData->classFilter != iteratorData->clazz)) {
if (iteratorData->event.type == J9JVMTI_HEAP_EVENT_NONE_REPORT_NOFOLLOW) {
return JVMTI_ITERATION_IGNORE;
} else {
return JVMTI_ITERATION_CONTINUE;
}
}
/* Does it pass the object filters specified by the user? */
if (((iteratorData->filter & JVMTI_HEAP_FILTER_TAGGED) && iteratorData->tags.objectTag != (jlong) 0) || /* filter out tagged objects */
((iteratorData->filter & JVMTI_HEAP_FILTER_UNTAGGED) && iteratorData->tags.objectTag == (jlong) 0)) { /* filter out untagged objects */
return JVMTI_ITERATION_CONTINUE;
}
/* Does it pass the class filters specified by the user? */
if (((iteratorData->filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) && iteratorData->tags.classTag != (jlong) 0) || /* filter out tagged classes */
((iteratorData->filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) && iteratorData->tags.classTag == (jlong) 0)) { /* filter out untagged classes */
return JVMTI_ITERATION_CONTINUE;
}
return -1;
}
static jvmtiIterationControl
wrap_heapReferenceCallback(J9JavaVM * vm, J9JVMTIHeapData * iteratorData)
{
jvmtiIterationControl visitRc = JVMTI_ITERATION_ABORT;
J9JVMTIHeapEvent * e = &iteratorData->event;
jint length;
jlong objectTag;
jlong referrerObjectTag;
/* Details about the reference. Set when the reference_kind is
* JVMTI_HEAP_REFERENCE_FIELD,
* JVMTI_HEAP_REFERENCE_STATIC_FIELD,
* JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT,
* JVMTI_HEAP_REFERENCE_CONSTANT_POOL,
* JVMTI_HEAP_REFERENCE_STACK_LOCAL,
* JVMTI_HEAP_REFERENCE_JNI_LOCAL.
* Otherwise NULL. */
switch (e->refKind) {
case JVMTI_HEAP_REFERENCE_FIELD:
case JVMTI_HEAP_REFERENCE_STATIC_FIELD:
case JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT:
case JVMTI_HEAP_REFERENCE_CONSTANT_POOL:
/* The indices are filled in while mapping between GC and JVMTI event types */
break;
case JVMTI_HEAP_REFERENCE_STACK_LOCAL:
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)
return JVMTI_ITERATION_IGNORE;
} else {
/* No reference info available for heap roots, slime some bogus values
* to prevent hprof from crashing.
* TODO: this is a temporary hack which has to be corrected by the GC returning us valid
* referer/walkstate info for heap roots */
if (e->refKind == JVMTI_HEAP_REFERENCE_STACK_LOCAL) {
e->refInfo.stack_local.thread_tag = 0;
e->refInfo.stack_local.thread_id = 0;
e->refInfo.stack_local.depth = -1;
e->refInfo.stack_local.method = NULL;
e->refInfo.stack_local.location = 0;
e->refInfo.stack_local.slot = 0;
} else {
e->refInfo.jni_local.thread_tag = 0;
e->refInfo.jni_local.thread_id = 0;
e->refInfo.jni_local.depth = -1;
e->refInfo.jni_local.method = NULL;
}
}
break;
default:
/* According to the spec, on references other then above, we are required to pass a
* NULL reference info structure */
e->hasRefInfo = FALSE;
break;
}
objectTag = iteratorData->tags.objectTag;
referrerObjectTag = iteratorData->tags.referrerObjectTag;
/* The callback wants to know the array size (if the referee is an array) */
if (J9ROMCLASS_IS_ARRAY(iteratorData->clazz->romClass)) {
length = J9INDEXABLEOBJECT_SIZE(iteratorData->currentThread, (J9IndexableObject *) iteratorData->object);
} else {
length = -1;
}
/* Callback the user */
visitRc = iteratorData->callbacks->heap_reference_callback(
e->refKind,
e->hasRefInfo ? &e->refInfo : NULL,
iteratorData->tags.classTag,
(e->type == J9JVMTI_HEAP_EVENT_ROOT || e->type == J9JVMTI_HEAP_EVENT_STACK) ? 0 : iteratorData->tags.referrerClassTag,
iteratorData->objectSize,
&objectTag,
(e->type == J9JVMTI_HEAP_EVENT_ROOT || e->type == J9JVMTI_HEAP_EVENT_STACK) ? NULL : &referrerObjectTag,
length,
iteratorData->userData);
/* Update the object (referee) tag if it was changed by the user */
if (objectTag != iteratorData->tags.objectTag) {
updateObjectTag(iteratorData, iteratorData->object, &iteratorData->tags.objectTag, objectTag);
}
/* Update the referrer if it has changed. We ignore any objects that are Heap Roots as per spec */
if (e->type != J9JVMTI_HEAP_EVENT_ROOT && e->type != J9JVMTI_HEAP_EVENT_STACK) {
if (referrerObjectTag != iteratorData->tags.referrerObjectTag)
updateObjectTag(iteratorData, iteratorData->referrer, &iteratorData->tags.referrerObjectTag, referrerObjectTag);
}
if (visitRc & JVMTI_VISIT_ABORT) {
return JVMTI_ITERATION_ABORT;
}
return JVMTI_ITERATION_CONTINUE;
}
/**
* \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
*
*/
static UDATA
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;
/* 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;
}
/* If there's no method, set slot, method and depth to -1 */
if (ramMethod == NULL) {
slot = -1;
depth = -1;
method = (jmethodID) -1;
} else {
/* Cheating here - should be current thread, but the walk thread will do */
method = getCurrentMethodID(walkState->walkThread, ramMethod);
if (method == NULL) {
slot = -1;
depth = -1;
method = (jmethodID) -1;
}
}
/* Find thread tag */
search.ref = (j9object_t ) walkState->walkThread->threadObject;
if (!AUTOTAGGING_OBJECTS(iteratorData->env)) {
result = hashTableFind(iteratorData->env->objectTagTable, &search);
} else {
search.tag = (jlong)(UDATA)search.ref;
result = &search;
}
/* Figure out the Thread ID */
threadID = J9VMJAVALANGTHREAD_TID(iteratorData->currentThread, walkState->walkThread->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;
}
return 1;
}
#ifdef JVMTI_HEAP_DEBUG
/**
* \brief You call, we print
* \ingroup jvmti.heap
*
* @param[in] vm
* @param[in] e
* @param[in] object
* @param[in] referrer
*
*/
static void
jvmtiHeapFollowReferencesPrint(J9JavaVM * vm, j9object_t object, j9object_t referrer, J9JVMTIHeapData * iteratorData)
{
J9UTF8 *c, *rc;
J9JVMTIHeapEvent * e = &iteratorData->event;
const char *refName = jvmtiHeapReferenceKindString(e->refKind);
char referrerName[256];
char refereeName[256];
J9Class* clazz;
if (J9VM_IS_INITIALIZED_HEAPCLASS(iteratorData, object)) {
clazz = J9VM_J9CLASS_FROM_HEAPCLASS(iteratorData->currentThread, object);
c = J9ROMCLASS_CLASSNAME(clazz->romClass);
} else {
clazz = J9OBJECT_CLAZZ(vm, object);
c = J9ROMCLASS_CLASSNAME(clazz->romClass);
}
strncpy(refereeName, J9UTF8_DATA(c), J9UTF8_LENGTH(c));
refereeName[J9UTF8_LENGTH(c)] = 0;
if (e->type != J9JVMTI_HEAP_EVENT_STACK && referrer != NULL) {
if (J9VM_IS_INITIALIZED_HEAPCLASS(vm, referrer)) {
J9Class* referrerClazz = J9VM_J9CLASS_FROM_HEAPCLASS(iteratorData->currentThread, referrer);
rc = J9ROMCLASS_CLASSNAME(referrerClazz->romClass);
} else {
J9Class* referrerClazz = J9OBJECT_CLAZZ(iteratorData->currentThread, referrer);
rc = J9ROMCLASS_CLASSNAME(referrerClazz->romClass);
}
strncpy(referrerName, J9UTF8_DATA(rc), J9UTF8_LENGTH(rc));
referrerName[J9UTF8_LENGTH(rc)] = 0;
} else {
strcpy(referrerName, "null");
rc = NULL;
}
jvmtiHeapFR_printf(("\tev=0x%02x [%d] refType=0x%x [%-17s] idx=%d [%s] -> [%s] flds=%-3d [%08llx:%08llx]->[%08llx:%08llx]\n",
e->type, e->gcType, e->refKind, refName,
e->refInfo.field.index,
referrerName, refereeName,
clazz->romClass->romFieldCount,
(rc) ? iteratorData->tags.referrerClassTag & 0xffffffff : 0xffffffff,
(rc) ? iteratorData->tags.referrerObjectTag & 0xffffffff : 0xffffffff,
iteratorData->tags.classTag & 0xffffffff,
iteratorData->tags.objectTag & 0xffffffff));
return;
}
#endif
/**
* \brief Obtain tags for the Referrer and Referee objects
* \ingroup jvmti.heap
*
* @param iteratorData iteration structure containing misc data
* @param referrer referrer object
* @param object referee object referred to by referrer
*
*/
static void
jvmtiFollowRefs_getTags(J9JVMTIHeapData * iteratorData, j9object_t referrer, j9object_t object)
{