--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/prims/jvmtiTagMap.cpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,3428 @@
+/*
+ * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "classfile/javaClasses.inline.hpp"
+#include "classfile/symbolTable.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "classfile/vmSymbols.hpp"
+#include "code/codeCache.hpp"
+#include "jvmtifiles/jvmtiEnv.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/instanceMirrorKlass.hpp"
+#include "oops/objArrayKlass.hpp"
+#include "oops/objArrayOop.inline.hpp"
+#include "oops/oop.inline.hpp"
+#include "prims/jvmtiEventController.hpp"
+#include "prims/jvmtiEventController.inline.hpp"
+#include "prims/jvmtiExport.hpp"
+#include "prims/jvmtiImpl.hpp"
+#include "prims/jvmtiTagMap.hpp"
+#include "runtime/biasedLocking.hpp"
+#include "runtime/javaCalls.hpp"
+#include "runtime/jniHandles.hpp"
+#include "runtime/mutex.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/reflectionUtils.hpp"
+#include "runtime/vframe.hpp"
+#include "runtime/vmThread.hpp"
+#include "runtime/vm_operations.hpp"
+#include "services/serviceUtil.hpp"
+#include "utilities/macros.hpp"
+#if INCLUDE_ALL_GCS
+#include "gc/g1/g1SATBCardTableModRefBS.hpp"
+#include "gc/parallel/parallelScavengeHeap.hpp"
+#endif // INCLUDE_ALL_GCS
+
+// JvmtiTagHashmapEntry
+//
+// Each entry encapsulates a reference to the tagged object
+// and the tag value. In addition an entry includes a next pointer which
+// is used to chain entries together.
+
+class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
+ private:
+ friend class JvmtiTagMap;
+
+ oop _object; // tagged object
+ jlong _tag; // the tag
+ JvmtiTagHashmapEntry* _next; // next on the list
+
+ inline void init(oop object, jlong tag) {
+ _object = object;
+ _tag = tag;
+ _next = NULL;
+ }
+
+ // constructor
+ JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
+
+ public:
+
+ // accessor methods
+ inline oop object() const { return _object; }
+ inline oop* object_addr() { return &_object; }
+ inline jlong tag() const { return _tag; }
+
+ inline void set_tag(jlong tag) {
+ assert(tag != 0, "can't be zero");
+ _tag = tag;
+ }
+
+ inline JvmtiTagHashmapEntry* next() const { return _next; }
+ inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
+};
+
+
+// JvmtiTagHashmap
+//
+// A hashmap is essentially a table of pointers to entries. Entries
+// are hashed to a location, or position in the table, and then
+// chained from that location. The "key" for hashing is address of
+// the object, or oop. The "value" is the tag value.
+//
+// A hashmap maintains a count of the number entries in the hashmap
+// and resizes if the number of entries exceeds a given threshold.
+// The threshold is specified as a percentage of the size - for
+// example a threshold of 0.75 will trigger the hashmap to resize
+// if the number of entries is >75% of table size.
+//
+// A hashmap provides functions for adding, removing, and finding
+// entries. It also provides a function to iterate over all entries
+// in the hashmap.
+
+class JvmtiTagHashmap : public CHeapObj<mtInternal> {
+ private:
+ friend class JvmtiTagMap;
+
+ enum {
+ small_trace_threshold = 10000, // threshold for tracing
+ medium_trace_threshold = 100000,
+ large_trace_threshold = 1000000,
+ initial_trace_threshold = small_trace_threshold
+ };
+
+ static int _sizes[]; // array of possible hashmap sizes
+ int _size; // actual size of the table
+ int _size_index; // index into size table
+
+ int _entry_count; // number of entries in the hashmap
+
+ float _load_factor; // load factor as a % of the size
+ int _resize_threshold; // computed threshold to trigger resizing.
+ bool _resizing_enabled; // indicates if hashmap can resize
+
+ int _trace_threshold; // threshold for trace messages
+
+ JvmtiTagHashmapEntry** _table; // the table of entries.
+
+ // private accessors
+ int resize_threshold() const { return _resize_threshold; }
+ int trace_threshold() const { return _trace_threshold; }
+
+ // initialize the hashmap
+ void init(int size_index=0, float load_factor=4.0f) {
+ int initial_size = _sizes[size_index];
+ _size_index = size_index;
+ _size = initial_size;
+ _entry_count = 0;
+ _trace_threshold = initial_trace_threshold;
+ _load_factor = load_factor;
+ _resize_threshold = (int)(_load_factor * _size);
+ _resizing_enabled = true;
+ size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*);
+ _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
+ if (_table == NULL) {
+ vm_exit_out_of_memory(s, OOM_MALLOC_ERROR,
+ "unable to allocate initial hashtable for jvmti object tags");
+ }
+ for (int i=0; i<initial_size; i++) {
+ _table[i] = NULL;
+ }
+ }
+
+ // hash a given key (oop) with the specified size
+ static unsigned int hash(oop key, int size) {
+ // shift right to get better distribution (as these bits will be zero
+ // with aligned addresses)
+ unsigned int addr = (unsigned int)(cast_from_oop<intptr_t>(key));
+#ifdef _LP64
+ return (addr >> 3) % size;
+#else
+ return (addr >> 2) % size;
+#endif
+ }
+
+ // hash a given key (oop)
+ unsigned int hash(oop key) {
+ return hash(key, _size);
+ }
+
+ // resize the hashmap - allocates a large table and re-hashes
+ // all entries into the new table.
+ void resize() {
+ int new_size_index = _size_index+1;
+ int new_size = _sizes[new_size_index];
+ if (new_size < 0) {
+ // hashmap already at maximum capacity
+ return;
+ }
+
+ // allocate new table
+ size_t s = new_size * sizeof(JvmtiTagHashmapEntry*);
+ JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
+ if (new_table == NULL) {
+ warning("unable to allocate larger hashtable for jvmti object tags");
+ set_resizing_enabled(false);
+ return;
+ }
+
+ // initialize new table
+ int i;
+ for (i=0; i<new_size; i++) {
+ new_table[i] = NULL;
+ }
+
+ // rehash all entries into the new table
+ for (i=0; i<_size; i++) {
+ JvmtiTagHashmapEntry* entry = _table[i];
+ while (entry != NULL) {
+ JvmtiTagHashmapEntry* next = entry->next();
+ oop key = entry->object();
+ assert(key != NULL, "jni weak reference cleared!!");
+ unsigned int h = hash(key, new_size);
+ JvmtiTagHashmapEntry* anchor = new_table[h];
+ if (anchor == NULL) {
+ new_table[h] = entry;
+ entry->set_next(NULL);
+ } else {
+ entry->set_next(anchor);
+ new_table[h] = entry;
+ }
+ entry = next;
+ }
+ }
+
+ // free old table and update settings.
+ os::free((void*)_table);
+ _table = new_table;
+ _size_index = new_size_index;
+ _size = new_size;
+
+ // compute new resize threshold
+ _resize_threshold = (int)(_load_factor * _size);
+ }
+
+
+ // internal remove function - remove an entry at a given position in the
+ // table.
+ inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) {
+ assert(pos >= 0 && pos < _size, "out of range");
+ if (prev == NULL) {
+ _table[pos] = entry->next();
+ } else {
+ prev->set_next(entry->next());
+ }
+ assert(_entry_count > 0, "checking");
+ _entry_count--;
+ }
+
+ // resizing switch
+ bool is_resizing_enabled() const { return _resizing_enabled; }
+ void set_resizing_enabled(bool enable) { _resizing_enabled = enable; }
+
+ // debugging
+ void print_memory_usage();
+ void compute_next_trace_threshold();
+
+ public:
+
+ // create a JvmtiTagHashmap of a preferred size and optionally a load factor.
+ // The preferred size is rounded down to an actual size.
+ JvmtiTagHashmap(int size, float load_factor=0.0f) {
+ int i=0;
+ while (_sizes[i] < size) {
+ if (_sizes[i] < 0) {
+ assert(i > 0, "sanity check");
+ i--;
+ break;
+ }
+ i++;
+ }
+
+ // if a load factor is specified then use it, otherwise use default
+ if (load_factor > 0.01f) {
+ init(i, load_factor);
+ } else {
+ init(i);
+ }
+ }
+
+ // create a JvmtiTagHashmap with default settings
+ JvmtiTagHashmap() {
+ init();
+ }
+
+ // release table when JvmtiTagHashmap destroyed
+ ~JvmtiTagHashmap() {
+ if (_table != NULL) {
+ os::free((void*)_table);
+ _table = NULL;
+ }
+ }
+
+ // accessors
+ int size() const { return _size; }
+ JvmtiTagHashmapEntry** table() const { return _table; }
+ int entry_count() const { return _entry_count; }
+
+ // find an entry in the hashmap, returns NULL if not found.
+ inline JvmtiTagHashmapEntry* find(oop key) {
+ unsigned int h = hash(key);
+ JvmtiTagHashmapEntry* entry = _table[h];
+ while (entry != NULL) {
+ if (entry->object() == key) {
+ return entry;
+ }
+ entry = entry->next();
+ }
+ return NULL;
+ }
+
+
+ // add a new entry to hashmap
+ inline void add(oop key, JvmtiTagHashmapEntry* entry) {
+ assert(key != NULL, "checking");
+ assert(find(key) == NULL, "duplicate detected");
+ unsigned int h = hash(key);
+ JvmtiTagHashmapEntry* anchor = _table[h];
+ if (anchor == NULL) {
+ _table[h] = entry;
+ entry->set_next(NULL);
+ } else {
+ entry->set_next(anchor);
+ _table[h] = entry;
+ }
+
+ _entry_count++;
+ if (log_is_enabled(Debug, jvmti, objecttagging) && entry_count() >= trace_threshold()) {
+ print_memory_usage();
+ compute_next_trace_threshold();
+ }
+
+ // if the number of entries exceed the threshold then resize
+ if (entry_count() > resize_threshold() && is_resizing_enabled()) {
+ resize();
+ }
+ }
+
+ // remove an entry with the given key.
+ inline JvmtiTagHashmapEntry* remove(oop key) {
+ unsigned int h = hash(key);
+ JvmtiTagHashmapEntry* entry = _table[h];
+ JvmtiTagHashmapEntry* prev = NULL;
+ while (entry != NULL) {
+ if (key == entry->object()) {
+ break;
+ }
+ prev = entry;
+ entry = entry->next();
+ }
+ if (entry != NULL) {
+ remove(prev, h, entry);
+ }
+ return entry;
+ }
+
+ // iterate over all entries in the hashmap
+ void entry_iterate(JvmtiTagHashmapEntryClosure* closure);
+};
+
+// possible hashmap sizes - odd primes that roughly double in size.
+// To avoid excessive resizing the odd primes from 4801-76831 and
+// 76831-307261 have been removed. The list must be terminated by -1.
+int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891,
+ 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 };
+
+
+// A supporting class for iterating over all entries in Hashmap
+class JvmtiTagHashmapEntryClosure {
+ public:
+ virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0;
+};
+
+
+// iterate over all entries in the hashmap
+void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
+ for (int i=0; i<_size; i++) {
+ JvmtiTagHashmapEntry* entry = _table[i];
+ JvmtiTagHashmapEntry* prev = NULL;
+ while (entry != NULL) {
+ // obtain the next entry before invoking do_entry - this is
+ // necessary because do_entry may remove the entry from the
+ // hashmap.
+ JvmtiTagHashmapEntry* next = entry->next();
+ closure->do_entry(entry);
+ entry = next;
+ }
+ }
+}
+
+// debugging
+void JvmtiTagHashmap::print_memory_usage() {
+ intptr_t p = (intptr_t)this;
+ tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p);
+
+ // table + entries in KB
+ int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) +
+ entry_count()*sizeof(JvmtiTagHashmapEntry))/K;
+
+ int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K);
+ tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]",
+ entry_count(), hashmap_usage, weak_globals_usage);
+}
+
+// compute threshold for the next trace message
+void JvmtiTagHashmap::compute_next_trace_threshold() {
+ _trace_threshold = entry_count();
+ if (trace_threshold() < medium_trace_threshold) {
+ _trace_threshold += small_trace_threshold;
+ } else {
+ if (trace_threshold() < large_trace_threshold) {
+ _trace_threshold += medium_trace_threshold;
+ } else {
+ _trace_threshold += large_trace_threshold;
+ }
+ }
+}
+
+// create a JvmtiTagMap
+JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
+ _env(env),
+ _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false),
+ _free_entries(NULL),
+ _free_entries_count(0)
+{
+ assert(JvmtiThreadState_lock->is_locked(), "sanity check");
+ assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
+
+ _hashmap = new JvmtiTagHashmap();
+
+ // finally add us to the environment
+ ((JvmtiEnvBase *)env)->set_tag_map(this);
+}
+
+
+// destroy a JvmtiTagMap
+JvmtiTagMap::~JvmtiTagMap() {
+
+ // no lock acquired as we assume the enclosing environment is
+ // also being destroryed.
+ ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
+
+ JvmtiTagHashmapEntry** table = _hashmap->table();
+ for (int j = 0; j < _hashmap->size(); j++) {
+ JvmtiTagHashmapEntry* entry = table[j];
+ while (entry != NULL) {
+ JvmtiTagHashmapEntry* next = entry->next();
+ delete entry;
+ entry = next;
+ }
+ }
+
+ // finally destroy the hashmap
+ delete _hashmap;
+ _hashmap = NULL;
+
+ // remove any entries on the free list
+ JvmtiTagHashmapEntry* entry = _free_entries;
+ while (entry != NULL) {
+ JvmtiTagHashmapEntry* next = entry->next();
+ delete entry;
+ entry = next;
+ }
+ _free_entries = NULL;
+}
+
+// create a hashmap entry
+// - if there's an entry on the (per-environment) free list then this
+// is returned. Otherwise an new entry is allocated.
+JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) {
+ assert(Thread::current()->is_VM_thread() || is_locked(), "checking");
+ JvmtiTagHashmapEntry* entry;
+ if (_free_entries == NULL) {
+ entry = new JvmtiTagHashmapEntry(ref, tag);
+ } else {
+ assert(_free_entries_count > 0, "mismatched _free_entries_count");
+ _free_entries_count--;
+ entry = _free_entries;
+ _free_entries = entry->next();
+ entry->init(ref, tag);
+ }
+ return entry;
+}
+
+// destroy an entry by returning it to the free list
+void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
+ assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
+ // limit the size of the free list
+ if (_free_entries_count >= max_free_entries) {
+ delete entry;
+ } else {
+ entry->set_next(_free_entries);
+ _free_entries = entry;
+ _free_entries_count++;
+ }
+}
+
+// returns the tag map for the given environments. If the tag map
+// doesn't exist then it is created.
+JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
+ JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map();
+ if (tag_map == NULL) {
+ MutexLocker mu(JvmtiThreadState_lock);
+ tag_map = ((JvmtiEnvBase*)env)->tag_map();
+ if (tag_map == NULL) {
+ tag_map = new JvmtiTagMap(env);
+ }
+ } else {
+ CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
+ }
+ return tag_map;
+}
+
+// iterate over all entries in the tag map.
+void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
+ hashmap()->entry_iterate(closure);
+}
+
+// returns true if the hashmaps are empty
+bool JvmtiTagMap::is_empty() {
+ assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
+ return hashmap()->entry_count() == 0;
+}
+
+
+// Return the tag value for an object, or 0 if the object is
+// not tagged
+//
+static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
+ JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o);
+ if (entry == NULL) {
+ return 0;
+ } else {
+ return entry->tag();
+ }
+}
+
+
+// A CallbackWrapper is a support class for querying and tagging an object
+// around a callback to a profiler. The constructor does pre-callback
+// work to get the tag value, klass tag value, ... and the destructor
+// does the post-callback work of tagging or untagging the object.
+//
+// {
+// CallbackWrapper wrapper(tag_map, o);
+//
+// (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
+//
+// } // wrapper goes out of scope here which results in the destructor
+// checking to see if the object has been tagged, untagged, or the
+// tag value has changed.
+//
+class CallbackWrapper : public StackObj {
+ private:
+ JvmtiTagMap* _tag_map;
+ JvmtiTagHashmap* _hashmap;
+ JvmtiTagHashmapEntry* _entry;
+ oop _o;
+ jlong _obj_size;
+ jlong _obj_tag;
+ jlong _klass_tag;
+
+ protected:
+ JvmtiTagMap* tag_map() const { return _tag_map; }
+
+ // invoked post-callback to tag, untag, or update the tag of an object
+ void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap,
+ JvmtiTagHashmapEntry* entry, jlong obj_tag);
+ public:
+ CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
+ assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
+ "MT unsafe or must be VM thread");
+
+ // object to tag
+ _o = o;
+
+ // object size
+ _obj_size = (jlong)_o->size() * wordSize;
+
+ // record the context
+ _tag_map = tag_map;
+ _hashmap = tag_map->hashmap();
+ _entry = _hashmap->find(_o);
+
+ // get object tag
+ _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
+
+ // get the class and the class's tag value
+ assert(SystemDictionary::Class_klass()->is_mirror_instance_klass(), "Is not?");
+
+ _klass_tag = tag_for(tag_map, _o->klass()->java_mirror());
+ }
+
+ ~CallbackWrapper() {
+ post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
+ }
+
+ inline jlong* obj_tag_p() { return &_obj_tag; }
+ inline jlong obj_size() const { return _obj_size; }
+ inline jlong obj_tag() const { return _obj_tag; }
+ inline jlong klass_tag() const { return _klass_tag; }
+};
+
+
+
+// callback post-callback to tag, untag, or update the tag of an object
+void inline CallbackWrapper::post_callback_tag_update(oop o,
+ JvmtiTagHashmap* hashmap,
+ JvmtiTagHashmapEntry* entry,
+ jlong obj_tag) {
+ if (entry == NULL) {
+ if (obj_tag != 0) {
+ // callback has tagged the object
+ assert(Thread::current()->is_VM_thread(), "must be VMThread");
+ entry = tag_map()->create_entry(o, obj_tag);
+ hashmap->add(o, entry);
+ }
+ } else {
+ // object was previously tagged - the callback may have untagged
+ // the object or changed the tag value
+ if (obj_tag == 0) {
+
+ JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o);
+ assert(entry_removed == entry, "checking");
+ tag_map()->destroy_entry(entry);
+
+ } else {
+ if (obj_tag != entry->tag()) {
+ entry->set_tag(obj_tag);
+ }
+ }
+ }
+}
+
+// An extended CallbackWrapper used when reporting an object reference
+// to the agent.
+//
+// {
+// TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
+//
+// (*callback)(wrapper.klass_tag(),
+// wrapper.obj_size(),
+// wrapper.obj_tag_p()
+// wrapper.referrer_tag_p(), ...)
+//
+// } // wrapper goes out of scope here which results in the destructor
+// checking to see if the referrer object has been tagged, untagged,
+// or the tag value has changed.
+//
+class TwoOopCallbackWrapper : public CallbackWrapper {
+ private:
+ bool _is_reference_to_self;
+ JvmtiTagHashmap* _referrer_hashmap;
+ JvmtiTagHashmapEntry* _referrer_entry;
+ oop _referrer;
+ jlong _referrer_obj_tag;
+ jlong _referrer_klass_tag;
+ jlong* _referrer_tag_p;
+
+ bool is_reference_to_self() const { return _is_reference_to_self; }
+
+ public:
+ TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
+ CallbackWrapper(tag_map, o)
+ {
+ // self reference needs to be handled in a special way
+ _is_reference_to_self = (referrer == o);
+
+ if (_is_reference_to_self) {
+ _referrer_klass_tag = klass_tag();
+ _referrer_tag_p = obj_tag_p();
+ } else {
+ _referrer = referrer;
+ // record the context
+ _referrer_hashmap = tag_map->hashmap();
+ _referrer_entry = _referrer_hashmap->find(_referrer);
+
+ // get object tag
+ _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
+ _referrer_tag_p = &_referrer_obj_tag;
+
+ // get referrer class tag.
+ _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror());
+ }
+ }
+
+ ~TwoOopCallbackWrapper() {
+ if (!is_reference_to_self()){
+ post_callback_tag_update(_referrer,
+ _referrer_hashmap,
+ _referrer_entry,
+ _referrer_obj_tag);
+ }
+ }
+
+ // address of referrer tag
+ // (for a self reference this will return the same thing as obj_tag_p())
+ inline jlong* referrer_tag_p() { return _referrer_tag_p; }
+
+ // referrer's class tag
+ inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
+};
+
+// tag an object
+//
+// This function is performance critical. If many threads attempt to tag objects
+// around the same time then it's possible that the Mutex associated with the
+// tag map will be a hot lock.
+void JvmtiTagMap::set_tag(jobject object, jlong tag) {
+ MutexLocker ml(lock());
+
+ // resolve the object
+ oop o = JNIHandles::resolve_non_null(object);
+
+ // see if the object is already tagged
+ JvmtiTagHashmap* hashmap = _hashmap;
+ JvmtiTagHashmapEntry* entry = hashmap->find(o);
+
+ // if the object is not already tagged then we tag it
+ if (entry == NULL) {
+ if (tag != 0) {
+ entry = create_entry(o, tag);
+ hashmap->add(o, entry);
+ } else {
+ // no-op
+ }
+ } else {
+ // if the object is already tagged then we either update
+ // the tag (if a new tag value has been provided)
+ // or remove the object if the new tag value is 0.
+ if (tag == 0) {
+ hashmap->remove(o);
+ destroy_entry(entry);
+ } else {
+ entry->set_tag(tag);
+ }
+ }
+}
+
+// get the tag for an object
+jlong JvmtiTagMap::get_tag(jobject object) {
+ MutexLocker ml(lock());
+
+ // resolve the object
+ oop o = JNIHandles::resolve_non_null(object);
+
+ return tag_for(this, o);
+}
+
+
+// Helper class used to describe the static or instance fields of a class.
+// For each field it holds the field index (as defined by the JVMTI specification),
+// the field type, and the offset.
+
+class ClassFieldDescriptor: public CHeapObj<mtInternal> {
+ private:
+ int _field_index;
+ int _field_offset;
+ char _field_type;
+ public:
+ ClassFieldDescriptor(int index, char type, int offset) :
+ _field_index(index), _field_type(type), _field_offset(offset) {
+ }
+ int field_index() const { return _field_index; }
+ char field_type() const { return _field_type; }
+ int field_offset() const { return _field_offset; }
+};
+
+class ClassFieldMap: public CHeapObj<mtInternal> {
+ private:
+ enum {
+ initial_field_count = 5
+ };
+
+ // list of field descriptors
+ GrowableArray<ClassFieldDescriptor*>* _fields;
+
+ // constructor
+ ClassFieldMap();
+
+ // add a field
+ void add(int index, char type, int offset);
+
+ // returns the field count for the given class
+ static int compute_field_count(InstanceKlass* ik);
+
+ public:
+ ~ClassFieldMap();
+
+ // access
+ int field_count() { return _fields->length(); }
+ ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
+
+ // functions to create maps of static or instance fields
+ static ClassFieldMap* create_map_of_static_fields(Klass* k);
+ static ClassFieldMap* create_map_of_instance_fields(oop obj);
+};
+
+ClassFieldMap::ClassFieldMap() {
+ _fields = new (ResourceObj::C_HEAP, mtInternal)
+ GrowableArray<ClassFieldDescriptor*>(initial_field_count, true);
+}
+
+ClassFieldMap::~ClassFieldMap() {
+ for (int i=0; i<_fields->length(); i++) {
+ delete _fields->at(i);
+ }
+ delete _fields;
+}
+
+void ClassFieldMap::add(int index, char type, int offset) {
+ ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
+ _fields->append(field);
+}
+
+// Returns a heap allocated ClassFieldMap to describe the static fields
+// of the given class.
+//
+ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
+ HandleMark hm;
+ InstanceKlass* ik = InstanceKlass::cast(k);
+
+ // create the field map
+ ClassFieldMap* field_map = new ClassFieldMap();
+
+ FilteredFieldStream f(ik, false, false);
+ int max_field_index = f.field_count()-1;
+
+ int index = 0;
+ for (FilteredFieldStream fld(ik, true, true); !fld.eos(); fld.next(), index++) {
+ // ignore instance fields
+ if (!fld.access_flags().is_static()) {
+ continue;
+ }
+ field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
+ }
+ return field_map;
+}
+
+// Returns a heap allocated ClassFieldMap to describe the instance fields
+// of the given class. All instance fields are included (this means public
+// and private fields declared in superclasses and superinterfaces too).
+//
+ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
+ HandleMark hm;
+ InstanceKlass* ik = InstanceKlass::cast(obj->klass());
+
+ // create the field map
+ ClassFieldMap* field_map = new ClassFieldMap();
+
+ FilteredFieldStream f(ik, false, false);
+
+ int max_field_index = f.field_count()-1;
+
+ int index = 0;
+ for (FilteredFieldStream fld(ik, false, false); !fld.eos(); fld.next(), index++) {
+ // ignore static fields
+ if (fld.access_flags().is_static()) {
+ continue;
+ }
+ field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
+ }
+
+ return field_map;
+}
+
+// Helper class used to cache a ClassFileMap for the instance fields of
+// a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
+// heap iteration and avoid creating a field map for each object in the heap
+// (only need to create the map when the first instance of a class is encountered).
+//
+class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
+ private:
+ enum {
+ initial_class_count = 200
+ };
+ ClassFieldMap* _field_map;
+
+ ClassFieldMap* field_map() const { return _field_map; }
+
+ JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
+ ~JvmtiCachedClassFieldMap();
+
+ static GrowableArray<InstanceKlass*>* _class_list;
+ static void add_to_class_list(InstanceKlass* ik);
+
+ public:
+ // returns the field map for a given object (returning map cached
+ // by InstanceKlass if possible
+ static ClassFieldMap* get_map_of_instance_fields(oop obj);
+
+ // removes the field map from all instanceKlasses - should be
+ // called before VM operation completes
+ static void clear_cache();
+
+ // returns the number of ClassFieldMap cached by instanceKlasses
+ static int cached_field_map_count();
+};
+
+GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
+
+JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
+ _field_map = field_map;
+}
+
+JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
+ if (_field_map != NULL) {
+ delete _field_map;
+ }
+}
+
+// Marker class to ensure that the class file map cache is only used in a defined
+// scope.
+class ClassFieldMapCacheMark : public StackObj {
+ private:
+ static bool _is_active;
+ public:
+ ClassFieldMapCacheMark() {
+ assert(Thread::current()->is_VM_thread(), "must be VMThread");
+ assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
+ assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
+ _is_active = true;
+ }
+ ~ClassFieldMapCacheMark() {
+ JvmtiCachedClassFieldMap::clear_cache();
+ _is_active = false;
+ }
+ static bool is_active() { return _is_active; }
+};
+
+bool ClassFieldMapCacheMark::_is_active;
+
+
+// record that the given InstanceKlass is caching a field map
+void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
+ if (_class_list == NULL) {
+ _class_list = new (ResourceObj::C_HEAP, mtInternal)
+ GrowableArray<InstanceKlass*>(initial_class_count, true);
+ }
+ _class_list->push(ik);
+}
+
+// returns the instance field map for the given object
+// (returns field map cached by the InstanceKlass if possible)
+ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
+ assert(Thread::current()->is_VM_thread(), "must be VMThread");
+ assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
+
+ Klass* k = obj->klass();
+ InstanceKlass* ik = InstanceKlass::cast(k);
+
+ // return cached map if possible
+ JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
+ if (cached_map != NULL) {
+ assert(cached_map->field_map() != NULL, "missing field list");
+ return cached_map->field_map();
+ } else {
+ ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
+ cached_map = new JvmtiCachedClassFieldMap(field_map);
+ ik->set_jvmti_cached_class_field_map(cached_map);
+ add_to_class_list(ik);
+ return field_map;
+ }
+}
+
+// remove the fields maps cached from all instanceKlasses
+void JvmtiCachedClassFieldMap::clear_cache() {
+ assert(Thread::current()->is_VM_thread(), "must be VMThread");
+ if (_class_list != NULL) {
+ for (int i = 0; i < _class_list->length(); i++) {
+ InstanceKlass* ik = _class_list->at(i);
+ JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
+ assert(cached_map != NULL, "should not be NULL");
+ ik->set_jvmti_cached_class_field_map(NULL);
+ delete cached_map; // deletes the encapsulated field map
+ }
+ delete _class_list;
+ _class_list = NULL;
+ }
+}
+
+// returns the number of ClassFieldMap cached by instanceKlasses
+int JvmtiCachedClassFieldMap::cached_field_map_count() {
+ return (_class_list == NULL) ? 0 : _class_list->length();
+}
+
+// helper function to indicate if an object is filtered by its tag or class tag
+static inline bool is_filtered_by_heap_filter(jlong obj_tag,
+ jlong klass_tag,
+ int heap_filter) {
+ // apply the heap filter
+ if (obj_tag != 0) {
+ // filter out tagged objects
+ if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
+ } else {
+ // filter out untagged objects
+ if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
+ }
+ if (klass_tag != 0) {
+ // filter out objects with tagged classes
+ if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
+ } else {
+ // filter out objects with untagged classes.
+ if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
+ }
+ return false;
+}
+
+// helper function to indicate if an object is filtered by a klass filter
+static inline bool is_filtered_by_klass_filter(oop obj, Klass* klass_filter) {
+ if (klass_filter != NULL) {
+ if (obj->klass() != klass_filter) {
+ return true;
+ }
+ }
+ return false;
+}
+
+// helper function to tell if a field is a primitive field or not
+static inline bool is_primitive_field_type(char type) {
+ return (type != 'L' && type != '[');
+}
+
+// helper function to copy the value from location addr to jvalue.
+static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
+ switch (value_type) {
+ case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
+ case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
+ case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
+ case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
+ case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
+ case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
+ case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
+ case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
+ default: ShouldNotReachHere();
+ }
+}
+
+// helper function to invoke string primitive value callback
+// returns visit control flags
+static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
+ CallbackWrapper* wrapper,
+ oop str,
+ void* user_data)
+{
+ assert(str->klass() == SystemDictionary::String_klass(), "not a string");
+
+ typeArrayOop s_value = java_lang_String::value(str);
+
+ // JDK-6584008: the value field may be null if a String instance is
+ // partially constructed.
+ if (s_value == NULL) {
+ return 0;
+ }
+ // get the string value and length
+ // (string value may be offset from the base)
+ int s_len = java_lang_String::length(str);
+ bool is_latin1 = java_lang_String::is_latin1(str);
+ jchar* value;
+ if (s_len > 0) {
+ if (!is_latin1) {
+ value = s_value->char_at_addr(0);
+ } else {
+ // Inflate latin1 encoded string to UTF16
+ jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
+ for (int i = 0; i < s_len; i++) {
+ buf[i] = ((jchar) s_value->byte_at(i)) & 0xff;
+ }
+ value = &buf[0];
+ }
+ } else {
+ // Don't use char_at_addr(0) if length is 0
+ value = (jchar*) s_value->base(T_CHAR);
+ }
+
+ // invoke the callback
+ jint res = (*cb)(wrapper->klass_tag(),
+ wrapper->obj_size(),
+ wrapper->obj_tag_p(),
+ value,
+ (jint)s_len,
+ user_data);
+
+ if (is_latin1 && s_len > 0) {
+ FREE_C_HEAP_ARRAY(jchar, value);
+ }
+ return res;
+}
+
+// helper function to invoke string primitive value callback
+// returns visit control flags
+static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
+ CallbackWrapper* wrapper,
+ oop obj,
+ void* user_data)
+{
+ assert(obj->is_typeArray(), "not a primitive array");
+
+ // get base address of first element
+ typeArrayOop array = typeArrayOop(obj);
+ BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
+ void* elements = array->base(type);
+
+ // jvmtiPrimitiveType is defined so this mapping is always correct
+ jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
+
+ return (*cb)(wrapper->klass_tag(),
+ wrapper->obj_size(),
+ wrapper->obj_tag_p(),
+ (jint)array->length(),
+ elem_type,
+ elements,
+ user_data);
+}
+
+// helper function to invoke the primitive field callback for all static fields
+// of a given class
+static jint invoke_primitive_field_callback_for_static_fields
+ (CallbackWrapper* wrapper,
+ oop obj,
+ jvmtiPrimitiveFieldCallback cb,
+ void* user_data)
+{
+ // for static fields only the index will be set
+ static jvmtiHeapReferenceInfo reference_info = { 0 };
+
+ assert(obj->klass() == SystemDictionary::Class_klass(), "not a class");
+ if (java_lang_Class::is_primitive(obj)) {
+ return 0;
+ }
+ Klass* klass = java_lang_Class::as_Klass(obj);
+
+ // ignore classes for object and type arrays
+ if (!klass->is_instance_klass()) {
+ return 0;
+ }
+
+ // ignore classes which aren't linked yet
+ InstanceKlass* ik = InstanceKlass::cast(klass);
+ if (!ik->is_linked()) {
+ return 0;
+ }
+
+ // get the field map
+ ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
+
+ // invoke the callback for each static primitive field
+ for (int i=0; i<field_map->field_count(); i++) {
+ ClassFieldDescriptor* field = field_map->field_at(i);
+
+ // ignore non-primitive fields
+ char type = field->field_type();
+ if (!is_primitive_field_type(type)) {
+ continue;
+ }
+ // one-to-one mapping
+ jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
+
+ // get offset and field value
+ int offset = field->field_offset();
+ address addr = (address)klass->java_mirror() + offset;
+ jvalue value;
+ copy_to_jvalue(&value, addr, value_type);
+
+ // field index
+ reference_info.field.index = field->field_index();
+
+ // invoke the callback
+ jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
+ &reference_info,
+ wrapper->klass_tag(),
+ wrapper->obj_tag_p(),
+ value,
+ value_type,
+ user_data);
+ if (res & JVMTI_VISIT_ABORT) {
+ delete field_map;
+ return res;
+ }
+ }
+
+ delete field_map;
+ return 0;
+}
+
+// helper function to invoke the primitive field callback for all instance fields
+// of a given object
+static jint invoke_primitive_field_callback_for_instance_fields(
+ CallbackWrapper* wrapper,
+ oop obj,
+ jvmtiPrimitiveFieldCallback cb,
+ void* user_data)
+{
+ // for instance fields only the index will be set
+ static jvmtiHeapReferenceInfo reference_info = { 0 };
+
+ // get the map of the instance fields
+ ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
+
+ // invoke the callback for each instance primitive field
+ for (int i=0; i<fields->field_count(); i++) {
+ ClassFieldDescriptor* field = fields->field_at(i);
+
+ // ignore non-primitive fields
+ char type = field->field_type();
+ if (!is_primitive_field_type(type)) {
+ continue;
+ }
+ // one-to-one mapping
+ jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
+
+ // get offset and field value
+ int offset = field->field_offset();
+ address addr = (address)obj + offset;
+ jvalue value;
+ copy_to_jvalue(&value, addr, value_type);
+
+ // field index
+ reference_info.field.index = field->field_index();
+
+ // invoke the callback
+ jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
+ &reference_info,
+ wrapper->klass_tag(),
+ wrapper->obj_tag_p(),
+ value,
+ value_type,
+ user_data);
+ if (res & JVMTI_VISIT_ABORT) {
+ return res;
+ }
+ }
+ return 0;
+}
+
+
+// VM operation to iterate over all objects in the heap (both reachable
+// and unreachable)
+class VM_HeapIterateOperation: public VM_Operation {
+ private:
+ ObjectClosure* _blk;
+ public:
+ VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; }
+
+ VMOp_Type type() const { return VMOp_HeapIterateOperation; }
+ void doit() {
+ // allows class files maps to be cached during iteration
+ ClassFieldMapCacheMark cm;
+
+ // make sure that heap is parsable (fills TLABs with filler objects)
+ Universe::heap()->ensure_parsability(false); // no need to retire TLABs
+
+ // Verify heap before iteration - if the heap gets corrupted then
+ // JVMTI's IterateOverHeap will crash.
+ if (VerifyBeforeIteration) {
+ Universe::verify();
+ }
+
+ // do the iteration
+ // If this operation encounters a bad object when using CMS,
+ // consider using safe_object_iterate() which avoids perm gen
+ // objects that may contain bad references.
+ Universe::heap()->object_iterate(_blk);
+ }
+
+};
+
+
+// An ObjectClosure used to support the deprecated IterateOverHeap and
+// IterateOverInstancesOfClass functions
+class IterateOverHeapObjectClosure: public ObjectClosure {
+ private:
+ JvmtiTagMap* _tag_map;
+ Klass* _klass;
+ jvmtiHeapObjectFilter _object_filter;
+ jvmtiHeapObjectCallback _heap_object_callback;
+ const void* _user_data;
+
+ // accessors
+ JvmtiTagMap* tag_map() const { return _tag_map; }
+ jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
+ jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
+ Klass* klass() const { return _klass; }
+ const void* user_data() const { return _user_data; }
+
+ // indicates if iteration has been aborted
+ bool _iteration_aborted;
+ bool is_iteration_aborted() const { return _iteration_aborted; }
+ void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
+
+ public:
+ IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
+ Klass* klass,
+ jvmtiHeapObjectFilter object_filter,
+ jvmtiHeapObjectCallback heap_object_callback,
+ const void* user_data) :
+ _tag_map(tag_map),
+ _klass(klass),
+ _object_filter(object_filter),
+ _heap_object_callback(heap_object_callback),
+ _user_data(user_data),
+ _iteration_aborted(false)
+ {
+ }
+
+ void do_object(oop o);
+};
+
+// invoked for each object in the heap
+void IterateOverHeapObjectClosure::do_object(oop o) {
+ // check if iteration has been halted
+ if (is_iteration_aborted()) return;
+
+ // ignore any objects that aren't visible to profiler
+ if (!ServiceUtil::visible_oop(o)) return;
+
+ // instanceof check when filtering by klass
+ if (klass() != NULL && !o->is_a(klass())) {
+ return;
+ }
+ // prepare for the calllback
+ CallbackWrapper wrapper(tag_map(), o);
+
+ // if the object is tagged and we're only interested in untagged objects
+ // then don't invoke the callback. Similiarly, if the object is untagged
+ // and we're only interested in tagged objects we skip the callback.
+ if (wrapper.obj_tag() != 0) {
+ if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
+ } else {
+ if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
+ }
+
+ // invoke the agent's callback
+ jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
+ wrapper.obj_size(),
+ wrapper.obj_tag_p(),
+ (void*)user_data());
+ if (control == JVMTI_ITERATION_ABORT) {
+ set_iteration_aborted(true);
+ }
+}
+
+// An ObjectClosure used to support the IterateThroughHeap function
+class IterateThroughHeapObjectClosure: public ObjectClosure {
+ private:
+ JvmtiTagMap* _tag_map;
+ Klass* _klass;
+ int _heap_filter;
+ const jvmtiHeapCallbacks* _callbacks;
+ const void* _user_data;
+
+ // accessor functions
+ JvmtiTagMap* tag_map() const { return _tag_map; }
+ int heap_filter() const { return _heap_filter; }
+ const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
+ Klass* klass() const { return _klass; }
+ const void* user_data() const { return _user_data; }
+
+ // indicates if the iteration has been aborted
+ bool _iteration_aborted;
+ bool is_iteration_aborted() const { return _iteration_aborted; }
+
+ // used to check the visit control flags. If the abort flag is set
+ // then we set the iteration aborted flag so that the iteration completes
+ // without processing any further objects
+ bool check_flags_for_abort(jint flags) {
+ bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
+ if (is_abort) {
+ _iteration_aborted = true;
+ }
+ return is_abort;
+ }
+
+ public:
+ IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
+ Klass* klass,
+ int heap_filter,
+ const jvmtiHeapCallbacks* heap_callbacks,
+ const void* user_data) :
+ _tag_map(tag_map),
+ _klass(klass),
+ _heap_filter(heap_filter),
+ _callbacks(heap_callbacks),
+ _user_data(user_data),
+ _iteration_aborted(false)
+ {
+ }
+
+ void do_object(oop o);
+};
+
+// invoked for each object in the heap
+void IterateThroughHeapObjectClosure::do_object(oop obj) {
+ // check if iteration has been halted
+ if (is_iteration_aborted()) return;
+
+ // ignore any objects that aren't visible to profiler
+ if (!ServiceUtil::visible_oop(obj)) return;
+
+ // apply class filter
+ if (is_filtered_by_klass_filter(obj, klass())) return;
+
+ // prepare for callback
+ CallbackWrapper wrapper(tag_map(), obj);
+
+ // check if filtered by the heap filter
+ if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
+ return;
+ }
+
+ // for arrays we need the length, otherwise -1
+ bool is_array = obj->is_array();
+ int len = is_array ? arrayOop(obj)->length() : -1;
+
+ // invoke the object callback (if callback is provided)
+ if (callbacks()->heap_iteration_callback != NULL) {
+ jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
+ jint res = (*cb)(wrapper.klass_tag(),
+ wrapper.obj_size(),
+ wrapper.obj_tag_p(),
+ (jint)len,
+ (void*)user_data());
+ if (check_flags_for_abort(res)) return;
+ }
+
+ // for objects and classes we report primitive fields if callback provided
+ if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
+ jint res;
+ jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
+ if (obj->klass() == SystemDictionary::Class_klass()) {
+ res = invoke_primitive_field_callback_for_static_fields(&wrapper,
+ obj,
+ cb,
+ (void*)user_data());
+ } else {
+ res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
+ obj,
+ cb,
+ (void*)user_data());
+ }
+ if (check_flags_for_abort(res)) return;
+ }
+
+ // string callback
+ if (!is_array &&
+ callbacks()->string_primitive_value_callback != NULL &&
+ obj->klass() == SystemDictionary::String_klass()) {
+ jint res = invoke_string_value_callback(
+ callbacks()->string_primitive_value_callback,
+ &wrapper,
+ obj,
+ (void*)user_data() );
+ if (check_flags_for_abort(res)) return;
+ }
+
+ // array callback
+ if (is_array &&
+ callbacks()->array_primitive_value_callback != NULL &&
+ obj->is_typeArray()) {
+ jint res = invoke_array_primitive_value_callback(
+ callbacks()->array_primitive_value_callback,
+ &wrapper,
+ obj,
+ (void*)user_data() );
+ if (check_flags_for_abort(res)) return;
+ }
+};
+
+
+// Deprecated function to iterate over all objects in the heap
+void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
+ Klass* klass,
+ jvmtiHeapObjectCallback heap_object_callback,
+ const void* user_data)
+{
+ MutexLocker ml(Heap_lock);
+ IterateOverHeapObjectClosure blk(this,
+ klass,
+ object_filter,
+ heap_object_callback,
+ user_data);
+ VM_HeapIterateOperation op(&blk);
+ VMThread::execute(&op);
+}
+
+
+// Iterates over all objects in the heap
+void JvmtiTagMap::iterate_through_heap(jint heap_filter,
+ Klass* klass,
+ const jvmtiHeapCallbacks* callbacks,
+ const void* user_data)
+{
+ MutexLocker ml(Heap_lock);
+ IterateThroughHeapObjectClosure blk(this,
+ klass,
+ heap_filter,
+ callbacks,
+ user_data);
+ VM_HeapIterateOperation op(&blk);
+ VMThread::execute(&op);
+}
+
+// support class for get_objects_with_tags
+
+class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
+ private:
+ JvmtiEnv* _env;
+ jlong* _tags;
+ jint _tag_count;
+
+ GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
+ GrowableArray<uint64_t>* _tag_results; // collected tags
+
+ public:
+ TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) {
+ _env = env;
+ _tags = (jlong*)tags;
+ _tag_count = tag_count;
+ _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true);
+ _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true);
+ }
+
+ ~TagObjectCollector() {
+ delete _object_results;
+ delete _tag_results;
+ }
+
+ // for each tagged object check if the tag value matches
+ // - if it matches then we create a JNI local reference to the object
+ // and record the reference and tag value.
+ //
+ void do_entry(JvmtiTagHashmapEntry* entry) {
+ for (int i=0; i<_tag_count; i++) {
+ if (_tags[i] == entry->tag()) {
+ oop o = entry->object();
+ assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check");
+#if INCLUDE_ALL_GCS
+ if (UseG1GC) {
+ // The reference in this tag map could be the only (implicitly weak)
+ // reference to that object. If we hand it out, we need to keep it live wrt
+ // SATB marking similar to other j.l.ref.Reference referents.
+ G1SATBCardTableModRefBS::enqueue(o);
+ }
+#endif
+ jobject ref = JNIHandles::make_local(JavaThread::current(), o);
+ _object_results->append(ref);
+ _tag_results->append((uint64_t)entry->tag());
+ }
+ }
+ }
+
+ // return the results from the collection
+ //
+ jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
+ jvmtiError error;
+ int count = _object_results->length();
+ assert(count >= 0, "sanity check");
+
+ // if object_result_ptr is not NULL then allocate the result and copy
+ // in the object references.
+ if (object_result_ptr != NULL) {
+ error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
+ if (error != JVMTI_ERROR_NONE) {
+ return error;
+ }
+ for (int i=0; i<count; i++) {
+ (*object_result_ptr)[i] = _object_results->at(i);
+ }
+ }
+
+ // if tag_result_ptr is not NULL then allocate the result and copy
+ // in the tag values.
+ if (tag_result_ptr != NULL) {
+ error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
+ if (error != JVMTI_ERROR_NONE) {
+ if (object_result_ptr != NULL) {
+ _env->Deallocate((unsigned char*)object_result_ptr);
+ }
+ return error;
+ }
+ for (int i=0; i<count; i++) {
+ (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
+ }
+ }
+
+ *count_ptr = count;
+ return JVMTI_ERROR_NONE;
+ }
+};
+
+// return the list of objects with the specified tags
+jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
+ jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
+
+ TagObjectCollector collector(env(), tags, count);
+ {
+ // iterate over all tagged objects
+ MutexLocker ml(lock());
+ entry_iterate(&collector);
+ }
+ return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
+}
+
+
+// ObjectMarker is used to support the marking objects when walking the
+// heap.
+//
+// This implementation uses the existing mark bits in an object for
+// marking. Objects that are marked must later have their headers restored.
+// As most objects are unlocked and don't have their identity hash computed
+// we don't have to save their headers. Instead we save the headers that
+// are "interesting". Later when the headers are restored this implementation
+// restores all headers to their initial value and then restores the few
+// objects that had interesting headers.
+//
+// Future work: This implementation currently uses growable arrays to save
+// the oop and header of interesting objects. As an optimization we could
+// use the same technique as the GC and make use of the unused area
+// between top() and end().
+//
+
+// An ObjectClosure used to restore the mark bits of an object
+class RestoreMarksClosure : public ObjectClosure {
+ public:
+ void do_object(oop o) {
+ if (o != NULL) {
+ markOop mark = o->mark();
+ if (mark->is_marked()) {
+ o->init_mark();
+ }
+ }
+ }
+};
+
+// ObjectMarker provides the mark and visited functions
+class ObjectMarker : AllStatic {
+ private:
+ // saved headers
+ static GrowableArray<oop>* _saved_oop_stack;
+ static GrowableArray<markOop>* _saved_mark_stack;
+ static bool _needs_reset; // do we need to reset mark bits?
+
+ public:
+ static void init(); // initialize
+ static void done(); // clean-up
+
+ static inline void mark(oop o); // mark an object
+ static inline bool visited(oop o); // check if object has been visited
+
+ static inline bool needs_reset() { return _needs_reset; }
+ static inline void set_needs_reset(bool v) { _needs_reset = v; }
+};
+
+GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
+GrowableArray<markOop>* ObjectMarker::_saved_mark_stack = NULL;
+bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
+
+// initialize ObjectMarker - prepares for object marking
+void ObjectMarker::init() {
+ assert(Thread::current()->is_VM_thread(), "must be VMThread");
+
+ // prepare heap for iteration
+ Universe::heap()->ensure_parsability(false); // no need to retire TLABs
+
+ // create stacks for interesting headers
+ _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markOop>(4000, true);
+ _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
+
+ if (UseBiasedLocking) {
+ BiasedLocking::preserve_marks();
+ }
+}
+
+// Object marking is done so restore object headers
+void ObjectMarker::done() {
+ // iterate over all objects and restore the mark bits to
+ // their initial value
+ RestoreMarksClosure blk;
+ if (needs_reset()) {
+ Universe::heap()->object_iterate(&blk);
+ } else {
+ // We don't need to reset mark bits on this call, but reset the
+ // flag to the default for the next call.
+ set_needs_reset(true);
+ }
+
+ // now restore the interesting headers
+ for (int i = 0; i < _saved_oop_stack->length(); i++) {
+ oop o = _saved_oop_stack->at(i);
+ markOop mark = _saved_mark_stack->at(i);
+ o->set_mark(mark);
+ }
+
+ if (UseBiasedLocking) {
+ BiasedLocking::restore_marks();
+ }
+
+ // free the stacks
+ delete _saved_oop_stack;
+ delete _saved_mark_stack;
+}
+
+// mark an object
+inline void ObjectMarker::mark(oop o) {
+ assert(Universe::heap()->is_in(o), "sanity check");
+ assert(!o->mark()->is_marked(), "should only mark an object once");
+
+ // object's mark word
+ markOop mark = o->mark();
+
+ if (mark->must_be_preserved(o)) {
+ _saved_mark_stack->push(mark);
+ _saved_oop_stack->push(o);
+ }
+
+ // mark the object
+ o->set_mark(markOopDesc::prototype()->set_marked());
+}
+
+// return true if object is marked
+inline bool ObjectMarker::visited(oop o) {
+ return o->mark()->is_marked();
+}
+
+// Stack allocated class to help ensure that ObjectMarker is used
+// correctly. Constructor initializes ObjectMarker, destructor calls
+// ObjectMarker's done() function to restore object headers.
+class ObjectMarkerController : public StackObj {
+ public:
+ ObjectMarkerController() {
+ ObjectMarker::init();
+ }
+ ~ObjectMarkerController() {
+ ObjectMarker::done();
+ }
+};
+
+
+// helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
+// (not performance critical as only used for roots)
+static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
+ switch (kind) {
+ case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
+ case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
+ case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR;
+ case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
+ case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
+ case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
+ case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
+ default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
+ }
+}
+
+// Base class for all heap walk contexts. The base class maintains a flag
+// to indicate if the context is valid or not.
+class HeapWalkContext VALUE_OBJ_CLASS_SPEC {
+ private:
+ bool _valid;
+ public:
+ HeapWalkContext(bool valid) { _valid = valid; }
+ void invalidate() { _valid = false; }
+ bool is_valid() const { return _valid; }
+};
+
+// A basic heap walk context for the deprecated heap walking functions.
+// The context for a basic heap walk are the callbacks and fields used by
+// the referrer caching scheme.
+class BasicHeapWalkContext: public HeapWalkContext {
+ private:
+ jvmtiHeapRootCallback _heap_root_callback;
+ jvmtiStackReferenceCallback _stack_ref_callback;
+ jvmtiObjectReferenceCallback _object_ref_callback;
+
+ // used for caching
+ oop _last_referrer;
+ jlong _last_referrer_tag;
+
+ public:
+ BasicHeapWalkContext() : HeapWalkContext(false) { }
+
+ BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
+ jvmtiStackReferenceCallback stack_ref_callback,
+ jvmtiObjectReferenceCallback object_ref_callback) :
+ HeapWalkContext(true),
+ _heap_root_callback(heap_root_callback),
+ _stack_ref_callback(stack_ref_callback),
+ _object_ref_callback(object_ref_callback),
+ _last_referrer(NULL),
+ _last_referrer_tag(0) {
+ }
+
+ // accessors
+ jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
+ jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
+ jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
+
+ oop last_referrer() const { return _last_referrer; }
+ void set_last_referrer(oop referrer) { _last_referrer = referrer; }
+ jlong last_referrer_tag() const { return _last_referrer_tag; }
+ void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
+};
+
+// The advanced heap walk context for the FollowReferences functions.
+// The context is the callbacks, and the fields used for filtering.
+class AdvancedHeapWalkContext: public HeapWalkContext {
+ private:
+ jint _heap_filter;
+ Klass* _klass_filter;
+ const jvmtiHeapCallbacks* _heap_callbacks;
+
+ public:
+ AdvancedHeapWalkContext() : HeapWalkContext(false) { }
+
+ AdvancedHeapWalkContext(jint heap_filter,
+ Klass* klass_filter,
+ const jvmtiHeapCallbacks* heap_callbacks) :
+ HeapWalkContext(true),
+ _heap_filter(heap_filter),
+ _klass_filter(klass_filter),
+ _heap_callbacks(heap_callbacks) {
+ }
+
+ // accessors
+ jint heap_filter() const { return _heap_filter; }
+ Klass* klass_filter() const { return _klass_filter; }
+
+ const jvmtiHeapReferenceCallback heap_reference_callback() const {
+ return _heap_callbacks->heap_reference_callback;
+ };
+ const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
+ return _heap_callbacks->primitive_field_callback;
+ }
+ const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
+ return _heap_callbacks->array_primitive_value_callback;
+ }
+ const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
+ return _heap_callbacks->string_primitive_value_callback;
+ }
+};
+
+// The CallbackInvoker is a class with static functions that the heap walk can call
+// into to invoke callbacks. It works in one of two modes. The "basic" mode is
+// used for the deprecated IterateOverReachableObjects functions. The "advanced"
+// mode is for the newer FollowReferences function which supports a lot of
+// additional callbacks.
+class CallbackInvoker : AllStatic {
+ private:
+ // heap walk styles
+ enum { basic, advanced };
+ static int _heap_walk_type;
+ static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
+ static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
+
+ // context for basic style heap walk
+ static BasicHeapWalkContext _basic_context;
+ static BasicHeapWalkContext* basic_context() {
+ assert(_basic_context.is_valid(), "invalid");
+ return &_basic_context;
+ }
+
+ // context for advanced style heap walk
+ static AdvancedHeapWalkContext _advanced_context;
+ static AdvancedHeapWalkContext* advanced_context() {
+ assert(_advanced_context.is_valid(), "invalid");
+ return &_advanced_context;
+ }
+
+ // context needed for all heap walks
+ static JvmtiTagMap* _tag_map;
+ static const void* _user_data;
+ static GrowableArray<oop>* _visit_stack;
+
+ // accessors
+ static JvmtiTagMap* tag_map() { return _tag_map; }
+ static const void* user_data() { return _user_data; }
+ static GrowableArray<oop>* visit_stack() { return _visit_stack; }
+
+ // if the object hasn't been visited then push it onto the visit stack
+ // so that it will be visited later
+ static inline bool check_for_visit(oop obj) {
+ if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
+ return true;
+ }
+
+ // invoke basic style callbacks
+ static inline bool invoke_basic_heap_root_callback
+ (jvmtiHeapRootKind root_kind, oop obj);
+ static inline bool invoke_basic_stack_ref_callback
+ (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
+ int slot, oop obj);
+ static inline bool invoke_basic_object_reference_callback
+ (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
+
+ // invoke advanced style callbacks
+ static inline bool invoke_advanced_heap_root_callback
+ (jvmtiHeapReferenceKind ref_kind, oop obj);
+ static inline bool invoke_advanced_stack_ref_callback
+ (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
+ jmethodID method, jlocation bci, jint slot, oop obj);
+ static inline bool invoke_advanced_object_reference_callback
+ (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
+
+ // used to report the value of primitive fields
+ static inline bool report_primitive_field
+ (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
+
+ public:
+ // initialize for basic mode
+ static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
+ GrowableArray<oop>* visit_stack,
+ const void* user_data,
+ BasicHeapWalkContext context);
+
+ // initialize for advanced mode
+ static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
+ GrowableArray<oop>* visit_stack,
+ const void* user_data,
+ AdvancedHeapWalkContext context);
+
+ // functions to report roots
+ static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
+ static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
+ jmethodID m, oop o);
+ static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
+ jmethodID method, jlocation bci, jint slot, oop o);
+
+ // functions to report references
+ static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
+ static inline bool report_class_reference(oop referrer, oop referree);
+ static inline bool report_class_loader_reference(oop referrer, oop referree);
+ static inline bool report_signers_reference(oop referrer, oop referree);
+ static inline bool report_protection_domain_reference(oop referrer, oop referree);
+ static inline bool report_superclass_reference(oop referrer, oop referree);
+ static inline bool report_interface_reference(oop referrer, oop referree);
+ static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
+ static inline bool report_field_reference(oop referrer, oop referree, jint slot);
+ static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
+ static inline bool report_primitive_array_values(oop array);
+ static inline bool report_string_value(oop str);
+ static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
+ static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
+};
+
+// statics
+int CallbackInvoker::_heap_walk_type;
+BasicHeapWalkContext CallbackInvoker::_basic_context;
+AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
+JvmtiTagMap* CallbackInvoker::_tag_map;
+const void* CallbackInvoker::_user_data;
+GrowableArray<oop>* CallbackInvoker::_visit_stack;
+
+// initialize for basic heap walk (IterateOverReachableObjects et al)
+void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
+ GrowableArray<oop>* visit_stack,
+ const void* user_data,
+ BasicHeapWalkContext context) {
+ _tag_map = tag_map;
+ _visit_stack = visit_stack;
+ _user_data = user_data;
+ _basic_context = context;
+ _advanced_context.invalidate(); // will trigger assertion if used
+ _heap_walk_type = basic;
+}
+
+// initialize for advanced heap walk (FollowReferences)
+void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
+ GrowableArray<oop>* visit_stack,
+ const void* user_data,
+ AdvancedHeapWalkContext context) {
+ _tag_map = tag_map;
+ _visit_stack = visit_stack;
+ _user_data = user_data;
+ _advanced_context = context;
+ _basic_context.invalidate(); // will trigger assertion if used
+ _heap_walk_type = advanced;
+}
+
+
+// invoke basic style heap root callback
+inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
+ assert(ServiceUtil::visible_oop(obj), "checking");
+
+ // if we heap roots should be reported
+ jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
+ if (cb == NULL) {
+ return check_for_visit(obj);
+ }
+
+ CallbackWrapper wrapper(tag_map(), obj);
+ jvmtiIterationControl control = (*cb)(root_kind,
+ wrapper.klass_tag(),
+ wrapper.obj_size(),
+ wrapper.obj_tag_p(),
+ (void*)user_data());
+ // push root to visit stack when following references
+ if (control == JVMTI_ITERATION_CONTINUE &&
+ basic_context()->object_ref_callback() != NULL) {
+ visit_stack()->push(obj);
+ }
+ return control != JVMTI_ITERATION_ABORT;
+}
+
+// invoke basic style stack ref callback
+inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
+ jlong thread_tag,
+ jint depth,
+ jmethodID method,
+ jint slot,
+ oop obj) {
+ assert(ServiceUtil::visible_oop(obj), "checking");
+
+ // if we stack refs should be reported
+ jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
+ if (cb == NULL) {
+ return check_for_visit(obj);
+ }
+
+ CallbackWrapper wrapper(tag_map(), obj);
+ jvmtiIterationControl control = (*cb)(root_kind,
+ wrapper.klass_tag(),
+ wrapper.obj_size(),
+ wrapper.obj_tag_p(),
+ thread_tag,
+ depth,
+ method,
+ slot,
+ (void*)user_data());
+ // push root to visit stack when following references
+ if (control == JVMTI_ITERATION_CONTINUE &&
+ basic_context()->object_ref_callback() != NULL) {
+ visit_stack()->push(obj);
+ }
+ return control != JVMTI_ITERATION_ABORT;
+}
+
+// invoke basic style object reference callback
+inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
+ oop referrer,
+ oop referree,
+ jint index) {
+
+ assert(ServiceUtil::visible_oop(referrer), "checking");
+ assert(ServiceUtil::visible_oop(referree), "checking");
+
+ BasicHeapWalkContext* context = basic_context();
+
+ // callback requires the referrer's tag. If it's the same referrer
+ // as the last call then we use the cached value.
+ jlong referrer_tag;
+ if (referrer == context->last_referrer()) {
+ referrer_tag = context->last_referrer_tag();
+ } else {
+ referrer_tag = tag_for(tag_map(), referrer);
+ }
+
+ // do the callback
+ CallbackWrapper wrapper(tag_map(), referree);
+ jvmtiObjectReferenceCallback cb = context->object_ref_callback();
+ jvmtiIterationControl control = (*cb)(ref_kind,
+ wrapper.klass_tag(),
+ wrapper.obj_size(),
+ wrapper.obj_tag_p(),
+ referrer_tag,
+ index,
+ (void*)user_data());
+
+ // record referrer and referrer tag. For self-references record the
+ // tag value from the callback as this might differ from referrer_tag.
+ context->set_last_referrer(referrer);
+ if (referrer == referree) {
+ context->set_last_referrer_tag(*wrapper.obj_tag_p());
+ } else {
+ context->set_last_referrer_tag(referrer_tag);
+ }
+
+ if (control == JVMTI_ITERATION_CONTINUE) {
+ return check_for_visit(referree);
+ } else {
+ return control != JVMTI_ITERATION_ABORT;
+ }
+}
+
+// invoke advanced style heap root callback
+inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
+ oop obj) {
+ assert(ServiceUtil::visible_oop(obj), "checking");
+
+ AdvancedHeapWalkContext* context = advanced_context();
+
+ // check that callback is provided
+ jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
+ if (cb == NULL) {
+ return check_for_visit(obj);
+ }
+
+ // apply class filter
+ if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
+ return check_for_visit(obj);
+ }
+
+ // setup the callback wrapper
+ CallbackWrapper wrapper(tag_map(), obj);
+
+ // apply tag filter
+ if (is_filtered_by_heap_filter(wrapper.obj_tag(),
+ wrapper.klass_tag(),
+ context->heap_filter())) {
+ return check_for_visit(obj);
+ }
+
+ // for arrays we need the length, otherwise -1
+ jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
+
+ // invoke the callback
+ jint res = (*cb)(ref_kind,
+ NULL, // referrer info
+ wrapper.klass_tag(),
+ 0, // referrer_class_tag is 0 for heap root
+ wrapper.obj_size(),
+ wrapper.obj_tag_p(),
+ NULL, // referrer_tag_p
+ len,
+ (void*)user_data());
+ if (res & JVMTI_VISIT_ABORT) {
+ return false;// referrer class tag
+ }
+ if (res & JVMTI_VISIT_OBJECTS) {
+ check_for_visit(obj);
+ }
+ return true;
+}
+
+// report a reference from a thread stack to an object
+inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
+ jlong thread_tag,
+ jlong tid,
+ int depth,
+ jmethodID method,
+ jlocation bci,
+ jint slot,
+ oop obj) {
+ assert(ServiceUtil::visible_oop(obj), "checking");
+
+ AdvancedHeapWalkContext* context = advanced_context();
+
+ // check that callback is provider
+ jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
+ if (cb == NULL) {
+ return check_for_visit(obj);
+ }
+
+ // apply class filter
+ if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
+ return check_for_visit(obj);
+ }
+
+ // setup the callback wrapper
+ CallbackWrapper wrapper(tag_map(), obj);
+
+ // apply tag filter
+ if (is_filtered_by_heap_filter(wrapper.obj_tag(),
+ wrapper.klass_tag(),
+ context->heap_filter())) {
+ return check_for_visit(obj);
+ }
+
+ // setup the referrer info
+ jvmtiHeapReferenceInfo reference_info;
+ reference_info.stack_local.thread_tag = thread_tag;
+ reference_info.stack_local.thread_id = tid;
+ reference_info.stack_local.depth = depth;
+ reference_info.stack_local.method = method;
+ reference_info.stack_local.location = bci;
+ reference_info.stack_local.slot = slot;
+
+ // for arrays we need the length, otherwise -1
+ jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
+
+ // call into the agent
+ int res = (*cb)(ref_kind,
+ &reference_info,
+ wrapper.klass_tag(),
+ 0, // referrer_class_tag is 0 for heap root (stack)
+ wrapper.obj_size(),
+ wrapper.obj_tag_p(),
+ NULL, // referrer_tag is 0 for root
+ len,
+ (void*)user_data());
+
+ if (res & JVMTI_VISIT_ABORT) {
+ return false;
+ }
+ if (res & JVMTI_VISIT_OBJECTS) {
+ check_for_visit(obj);
+ }
+ return true;
+}
+
+// This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
+// only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
+#define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
+ | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
+ | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
+ | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
+ | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
+ | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
+
+// invoke the object reference callback to report a reference
+inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
+ oop referrer,
+ oop obj,
+ jint index)
+{
+ // field index is only valid field in reference_info
+ static jvmtiHeapReferenceInfo reference_info = { 0 };
+
+ assert(ServiceUtil::visible_oop(referrer), "checking");
+ assert(ServiceUtil::visible_oop(obj), "checking");
+
+ AdvancedHeapWalkContext* context = advanced_context();
+
+ // check that callback is provider
+ jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
+ if (cb == NULL) {
+ return check_for_visit(obj);
+ }
+
+ // apply class filter
+ if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
+ return check_for_visit(obj);
+ }
+
+ // setup the callback wrapper
+ TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
+
+ // apply tag filter
+ if (is_filtered_by_heap_filter(wrapper.obj_tag(),
+ wrapper.klass_tag(),
+ context->heap_filter())) {
+ return check_for_visit(obj);
+ }
+
+ // field index is only valid field in reference_info
+ reference_info.field.index = index;
+
+ // for arrays we need the length, otherwise -1
+ jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
+
+ // invoke the callback
+ int res = (*cb)(ref_kind,
+ (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
+ wrapper.klass_tag(),
+ wrapper.referrer_klass_tag(),
+ wrapper.obj_size(),
+ wrapper.obj_tag_p(),
+ wrapper.referrer_tag_p(),
+ len,
+ (void*)user_data());
+
+ if (res & JVMTI_VISIT_ABORT) {
+ return false;
+ }
+ if (res & JVMTI_VISIT_OBJECTS) {
+ check_for_visit(obj);
+ }
+ return true;
+}
+
+// report a "simple root"
+inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
+ assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
+ kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
+ assert(ServiceUtil::visible_oop(obj), "checking");
+
+ if (is_basic_heap_walk()) {
+ // map to old style root kind
+ jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
+ return invoke_basic_heap_root_callback(root_kind, obj);
+ } else {
+ assert(is_advanced_heap_walk(), "wrong heap walk type");
+ return invoke_advanced_heap_root_callback(kind, obj);
+ }
+}
+
+
+// invoke the primitive array values
+inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
+ assert(obj->is_typeArray(), "not a primitive array");
+
+ AdvancedHeapWalkContext* context = advanced_context();
+ assert(context->array_primitive_value_callback() != NULL, "no callback");
+
+ // apply class filter
+ if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
+ return true;
+ }
+
+ CallbackWrapper wrapper(tag_map(), obj);
+
+ // apply tag filter
+ if (is_filtered_by_heap_filter(wrapper.obj_tag(),
+ wrapper.klass_tag(),
+ context->heap_filter())) {
+ return true;
+ }
+
+ // invoke the callback
+ int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
+ &wrapper,
+ obj,
+ (void*)user_data());
+ return (!(res & JVMTI_VISIT_ABORT));
+}
+
+// invoke the string value callback
+inline bool CallbackInvoker::report_string_value(oop str) {
+ assert(str->klass() == SystemDictionary::String_klass(), "not a string");
+
+ AdvancedHeapWalkContext* context = advanced_context();
+ assert(context->string_primitive_value_callback() != NULL, "no callback");
+
+ // apply class filter
+ if (is_filtered_by_klass_filter(str, context->klass_filter())) {
+ return true;
+ }
+
+ CallbackWrapper wrapper(tag_map(), str);
+
+ // apply tag filter
+ if (is_filtered_by_heap_filter(wrapper.obj_tag(),
+ wrapper.klass_tag(),
+ context->heap_filter())) {
+ return true;
+ }
+
+ // invoke the callback
+ int res = invoke_string_value_callback(context->string_primitive_value_callback(),
+ &wrapper,
+ str,
+ (void*)user_data());
+ return (!(res & JVMTI_VISIT_ABORT));
+}
+
+// invoke the primitive field callback
+inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
+ oop obj,
+ jint index,
+ address addr,
+ char type)
+{
+ // for primitive fields only the index will be set
+ static jvmtiHeapReferenceInfo reference_info = { 0 };
+
+ AdvancedHeapWalkContext* context = advanced_context();
+ assert(context->primitive_field_callback() != NULL, "no callback");
+
+ // apply class filter
+ if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
+ return true;
+ }
+
+ CallbackWrapper wrapper(tag_map(), obj);
+
+ // apply tag filter
+ if (is_filtered_by_heap_filter(wrapper.obj_tag(),
+ wrapper.klass_tag(),
+ context->heap_filter())) {
+ return true;
+ }
+
+ // the field index in the referrer
+ reference_info.field.index = index;
+
+ // map the type
+ jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
+
+ // setup the jvalue
+ jvalue value;
+ copy_to_jvalue(&value, addr, value_type);
+
+ jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
+ int res = (*cb)(ref_kind,
+ &reference_info,
+ wrapper.klass_tag(),
+ wrapper.obj_tag_p(),
+ value,
+ value_type,
+ (void*)user_data());
+ return (!(res & JVMTI_VISIT_ABORT));
+}
+
+
+// instance field
+inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
+ jint index,
+ address value,
+ char type) {
+ return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
+ obj,
+ index,
+ value,
+ type);
+}
+
+// static field
+inline bool CallbackInvoker::report_primitive_static_field(oop obj,
+ jint index,
+ address value,
+ char type) {
+ return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
+ obj,
+ index,
+ value,
+ type);
+}
+
+// report a JNI local (root object) to the profiler
+inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
+ thread_tag,
+ depth,
+ m,
+ -1,
+ obj);
+ } else {
+ return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
+ thread_tag, tid,
+ depth,
+ m,
+ (jlocation)-1,
+ -1,
+ obj);
+ }
+}
+
+
+// report a local (stack reference, root object)
+inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
+ jlong tid,
+ jint depth,
+ jmethodID method,
+ jlocation bci,
+ jint slot,
+ oop obj) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
+ thread_tag,
+ depth,
+ method,
+ slot,
+ obj);
+ } else {
+ return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
+ thread_tag,
+ tid,
+ depth,
+ method,
+ bci,
+ slot,
+ obj);
+ }
+}
+
+// report an object referencing a class.
+inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
+ }
+}
+
+// report a class referencing its class loader.
+inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
+ }
+}
+
+// report a class referencing its signers.
+inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
+ }
+}
+
+// report a class referencing its protection domain..
+inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
+ }
+}
+
+// report a class referencing its superclass.
+inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
+ if (is_basic_heap_walk()) {
+ // Send this to be consistent with past implementation
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
+ }
+}
+
+// report a class referencing one of its interfaces.
+inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
+ }
+}
+
+// report a class referencing one of its static fields.
+inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
+ }
+}
+
+// report an array referencing an element object
+inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
+ }
+}
+
+// report an object referencing an instance field object
+inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
+ }
+}
+
+// report an array referencing an element object
+inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
+ if (is_basic_heap_walk()) {
+ return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
+ } else {
+ return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
+ }
+}
+
+// A supporting closure used to process simple roots
+class SimpleRootsClosure : public OopClosure {
+ private:
+ jvmtiHeapReferenceKind _kind;
+ bool _continue;
+
+ jvmtiHeapReferenceKind root_kind() { return _kind; }
+
+ public:
+ void set_kind(jvmtiHeapReferenceKind kind) {
+ _kind = kind;
+ _continue = true;
+ }
+
+ inline bool stopped() {
+ return !_continue;
+ }
+
+ void do_oop(oop* obj_p) {
+ // iteration has terminated
+ if (stopped()) {
+ return;
+ }
+
+ // ignore null or deleted handles
+ oop o = *obj_p;
+ if (o == NULL || o == JNIHandles::deleted_handle()) {
+ return;
+ }
+
+ assert(Universe::heap()->is_in_reserved(o), "should be impossible");
+
+ jvmtiHeapReferenceKind kind = root_kind();
+ if (kind == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) {
+ // SystemDictionary::always_strong_oops_do reports the application
+ // class loader as a root. We want this root to be reported as
+ // a root kind of "OTHER" rather than "SYSTEM_CLASS".
+ if (!o->is_instance() || !InstanceKlass::cast(o->klass())->is_mirror_instance_klass()) {
+ kind = JVMTI_HEAP_REFERENCE_OTHER;
+ }
+ }
+
+ // some objects are ignored - in the case of simple
+ // roots it's mostly Symbol*s that we are skipping
+ // here.
+ if (!ServiceUtil::visible_oop(o)) {
+ return;
+ }
+
+ // invoke the callback
+ _continue = CallbackInvoker::report_simple_root(kind, o);
+
+ }
+ virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
+};
+
+// A supporting closure used to process JNI locals
+class JNILocalRootsClosure : public OopClosure {
+ private:
+ jlong _thread_tag;
+ jlong _tid;
+ jint _depth;
+ jmethodID _method;
+ bool _continue;
+ public:
+ void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
+ _thread_tag = thread_tag;
+ _tid = tid;
+ _depth = depth;
+ _method = method;
+ _continue = true;
+ }
+
+ inline bool stopped() {
+ return !_continue;
+ }
+
+ void do_oop(oop* obj_p) {
+ // iteration has terminated
+ if (stopped()) {
+ return;
+ }
+
+ // ignore null or deleted handles
+ oop o = *obj_p;
+ if (o == NULL || o == JNIHandles::deleted_handle()) {
+ return;
+ }
+
+ if (!ServiceUtil::visible_oop(o)) {
+ return;
+ }
+
+ // invoke the callback
+ _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
+ }
+ virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
+};
+
+
+// A VM operation to iterate over objects that are reachable from
+// a set of roots or an initial object.
+//
+// For VM_HeapWalkOperation the set of roots used is :-
+//
+// - All JNI global references
+// - All inflated monitors
+// - All classes loaded by the boot class loader (or all classes
+// in the event that class unloading is disabled)
+// - All java threads
+// - For each java thread then all locals and JNI local references
+// on the thread's execution stack
+// - All visible/explainable objects from Universes::oops_do
+//
+class VM_HeapWalkOperation: public VM_Operation {
+ private:
+ enum {
+ initial_visit_stack_size = 4000
+ };
+
+ bool _is_advanced_heap_walk; // indicates FollowReferences
+ JvmtiTagMap* _tag_map;
+ Handle _initial_object;
+ GrowableArray<oop>* _visit_stack; // the visit stack
+
+ bool _collecting_heap_roots; // are we collecting roots
+ bool _following_object_refs; // are we following object references
+
+ bool _reporting_primitive_fields; // optional reporting
+ bool _reporting_primitive_array_values;
+ bool _reporting_string_values;
+
+ GrowableArray<oop>* create_visit_stack() {
+ return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true);
+ }
+
+ // accessors
+ bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
+ JvmtiTagMap* tag_map() const { return _tag_map; }
+ Handle initial_object() const { return _initial_object; }
+
+ bool is_following_references() const { return _following_object_refs; }
+
+ bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
+ bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
+ bool is_reporting_string_values() const { return _reporting_string_values; }
+
+ GrowableArray<oop>* visit_stack() const { return _visit_stack; }
+
+ // iterate over the various object types
+ inline bool iterate_over_array(oop o);
+ inline bool iterate_over_type_array(oop o);
+ inline bool iterate_over_class(oop o);
+ inline bool iterate_over_object(oop o);
+
+ // root collection
+ inline bool collect_simple_roots();
+ inline bool collect_stack_roots();
+ inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
+
+ // visit an object
+ inline bool visit(oop o);
+
+ public:
+ VM_HeapWalkOperation(JvmtiTagMap* tag_map,
+ Handle initial_object,
+ BasicHeapWalkContext callbacks,
+ const void* user_data);
+
+ VM_HeapWalkOperation(JvmtiTagMap* tag_map,
+ Handle initial_object,
+ AdvancedHeapWalkContext callbacks,
+ const void* user_data);
+
+ ~VM_HeapWalkOperation();
+
+ VMOp_Type type() const { return VMOp_HeapWalkOperation; }
+ void doit();
+};
+
+
+VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
+ Handle initial_object,
+ BasicHeapWalkContext callbacks,
+ const void* user_data) {
+ _is_advanced_heap_walk = false;
+ _tag_map = tag_map;
+ _initial_object = initial_object;
+ _following_object_refs = (callbacks.object_ref_callback() != NULL);
+ _reporting_primitive_fields = false;
+ _reporting_primitive_array_values = false;
+ _reporting_string_values = false;
+ _visit_stack = create_visit_stack();
+
+
+ CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
+}
+
+VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
+ Handle initial_object,
+ AdvancedHeapWalkContext callbacks,
+ const void* user_data) {
+ _is_advanced_heap_walk = true;
+ _tag_map = tag_map;
+ _initial_object = initial_object;
+ _following_object_refs = true;
+ _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
+ _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
+ _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
+ _visit_stack = create_visit_stack();
+
+ CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
+}
+
+VM_HeapWalkOperation::~VM_HeapWalkOperation() {
+ if (_following_object_refs) {
+ assert(_visit_stack != NULL, "checking");
+ delete _visit_stack;
+ _visit_stack = NULL;
+ }
+}
+
+// an array references its class and has a reference to
+// each element in the array
+inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
+ objArrayOop array = objArrayOop(o);
+
+ // array reference to its class
+ oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
+ if (!CallbackInvoker::report_class_reference(o, mirror)) {
+ return false;
+ }
+
+ // iterate over the array and report each reference to a
+ // non-null element
+ for (int index=0; index<array->length(); index++) {
+ oop elem = array->obj_at(index);
+ if (elem == NULL) {
+ continue;
+ }
+
+ // report the array reference o[index] = elem
+ if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
+ return false;
+ }
+ }
+ return true;
+}
+
+// a type array references its class
+inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
+ Klass* k = o->klass();
+ oop mirror = k->java_mirror();
+ if (!CallbackInvoker::report_class_reference(o, mirror)) {
+ return false;
+ }
+
+ // report the array contents if required
+ if (is_reporting_primitive_array_values()) {
+ if (!CallbackInvoker::report_primitive_array_values(o)) {
+ return false;
+ }
+ }
+ return true;
+}
+
+#ifdef ASSERT
+// verify that a static oop field is in range
+static inline bool verify_static_oop(InstanceKlass* ik,
+ oop mirror, int offset) {
+ address obj_p = (address)mirror + offset;
+ address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
+ address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
+ assert(end >= start, "sanity check");
+
+ if (obj_p >= start && obj_p < end) {
+ return true;
+ } else {
+ return false;
+ }
+}
+#endif // #ifdef ASSERT
+
+// a class references its super class, interfaces, class loader, ...
+// and finally its static fields
+inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
+ int i;
+ Klass* klass = java_lang_Class::as_Klass(java_class);
+
+ if (klass->is_instance_klass()) {
+ InstanceKlass* ik = InstanceKlass::cast(klass);
+
+ // Ignore the class if it hasn't been initialized yet
+ if (!ik->is_linked()) {
+ return true;
+ }
+
+ // get the java mirror
+ oop mirror = klass->java_mirror();
+
+ // super (only if something more interesting than java.lang.Object)
+ Klass* java_super = ik->java_super();
+ if (java_super != NULL && java_super != SystemDictionary::Object_klass()) {
+ oop super = java_super->java_mirror();
+ if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
+ return false;
+ }
+ }
+
+ // class loader
+ oop cl = ik->class_loader();
+ if (cl != NULL) {
+ if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
+ return false;
+ }
+ }
+
+ // protection domain
+ oop pd = ik->protection_domain();
+ if (pd != NULL) {
+ if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
+ return false;
+ }
+ }
+
+ // signers
+ oop signers = ik->signers();
+ if (signers != NULL) {
+ if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
+ return false;
+ }
+ }
+
+ // references from the constant pool
+ {
+ ConstantPool* pool = ik->constants();
+ for (int i = 1; i < pool->length(); i++) {
+ constantTag tag = pool->tag_at(i).value();
+ if (tag.is_string() || tag.is_klass()) {
+ oop entry;
+ if (tag.is_string()) {
+ entry = pool->resolved_string_at(i);
+ // If the entry is non-null it is resolved.
+ if (entry == NULL) continue;
+ } else {
+ entry = pool->resolved_klass_at(i)->java_mirror();
+ }
+ if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
+ return false;
+ }
+ }
+ }
+ }
+
+ // interfaces
+ // (These will already have been reported as references from the constant pool
+ // but are specified by IterateOverReachableObjects and must be reported).
+ Array<Klass*>* interfaces = ik->local_interfaces();
+ for (i = 0; i < interfaces->length(); i++) {
+ oop interf = ((Klass*)interfaces->at(i))->java_mirror();
+ if (interf == NULL) {
+ continue;
+ }
+ if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
+ return false;
+ }
+ }
+
+ // iterate over the static fields
+
+ ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
+ for (i=0; i<field_map->field_count(); i++) {
+ ClassFieldDescriptor* field = field_map->field_at(i);
+ char type = field->field_type();
+ if (!is_primitive_field_type(type)) {
+ oop fld_o = mirror->obj_field(field->field_offset());
+ assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
+ if (fld_o != NULL) {
+ int slot = field->field_index();
+ if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
+ delete field_map;
+ return false;
+ }
+ }
+ } else {
+ if (is_reporting_primitive_fields()) {
+ address addr = (address)mirror + field->field_offset();
+ int slot = field->field_index();
+ if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
+ delete field_map;
+ return false;
+ }
+ }
+ }
+ }
+ delete field_map;
+
+ return true;
+ }
+
+ return true;
+}
+
+// an object references a class and its instance fields
+// (static fields are ignored here as we report these as
+// references from the class).
+inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
+ // reference to the class
+ if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
+ return false;
+ }
+
+ // iterate over instance fields
+ ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
+ for (int i=0; i<field_map->field_count(); i++) {
+ ClassFieldDescriptor* field = field_map->field_at(i);
+ char type = field->field_type();
+ if (!is_primitive_field_type(type)) {
+ oop fld_o = o->obj_field(field->field_offset());
+ // ignore any objects that aren't visible to profiler
+ if (fld_o != NULL && ServiceUtil::visible_oop(fld_o)) {
+ assert(Universe::heap()->is_in_reserved(fld_o), "unsafe code should not "
+ "have references to Klass* anymore");
+ int slot = field->field_index();
+ if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
+ return false;
+ }
+ }
+ } else {
+ if (is_reporting_primitive_fields()) {
+ // primitive instance field
+ address addr = (address)o + field->field_offset();
+ int slot = field->field_index();
+ if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
+ return false;
+ }
+ }
+ }
+ }
+
+ // if the object is a java.lang.String
+ if (is_reporting_string_values() &&
+ o->klass() == SystemDictionary::String_klass()) {
+ if (!CallbackInvoker::report_string_value(o)) {
+ return false;
+ }
+ }
+ return true;
+}
+
+
+// Collects all simple (non-stack) roots except for threads;
+// threads are handled in collect_stack_roots() as an optimization.
+// if there's a heap root callback provided then the callback is
+// invoked for each simple root.
+// if an object reference callback is provided then all simple
+// roots are pushed onto the marking stack so that they can be
+// processed later
+//
+inline bool VM_HeapWalkOperation::collect_simple_roots() {
+ SimpleRootsClosure blk;
+
+ // JNI globals
+ blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
+ JNIHandles::oops_do(&blk);
+ if (blk.stopped()) {
+ return false;
+ }
+
+ // Preloaded classes and loader from the system dictionary
+ blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
+ SystemDictionary::always_strong_oops_do(&blk);
+ KlassToOopClosure klass_blk(&blk);
+ ClassLoaderDataGraph::always_strong_oops_do(&blk, &klass_blk, false);
+ if (blk.stopped()) {
+ return false;
+ }
+
+ // Inflated monitors
+ blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR);
+ ObjectSynchronizer::oops_do(&blk);
+ if (blk.stopped()) {
+ return false;
+ }
+
+ // threads are now handled in collect_stack_roots()
+
+ // Other kinds of roots maintained by HotSpot
+ // Many of these won't be visible but others (such as instances of important
+ // exceptions) will be visible.
+ blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
+ Universe::oops_do(&blk);
+
+ // If there are any non-perm roots in the code cache, visit them.
+ blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
+ CodeBlobToOopClosure look_in_blobs(&blk, !CodeBlobToOopClosure::FixRelocations);
+ CodeCache::scavenge_root_nmethods_do(&look_in_blobs);
+
+ return true;
+}
+
+// Walk the stack of a given thread and find all references (locals
+// and JNI calls) and report these as stack references
+inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
+ JNILocalRootsClosure* blk)
+{
+ oop threadObj = java_thread->threadObj();
+ assert(threadObj != NULL, "sanity check");
+
+ // only need to get the thread's tag once per thread
+ jlong thread_tag = tag_for(_tag_map, threadObj);
+
+ // also need the thread id
+ jlong tid = java_lang_Thread::thread_id(threadObj);
+
+
+ if (java_thread->has_last_Java_frame()) {
+
+ // vframes are resource allocated
+ Thread* current_thread = Thread::current();
+ ResourceMark rm(current_thread);
+ HandleMark hm(current_thread);
+
+ RegisterMap reg_map(java_thread);
+ frame f = java_thread->last_frame();
+ vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
+
+ bool is_top_frame = true;
+ int depth = 0;
+ frame* last_entry_frame = NULL;
+
+ while (vf != NULL) {
+ if (vf->is_java_frame()) {
+
+ // java frame (interpreted, compiled, ...)
+ javaVFrame *jvf = javaVFrame::cast(vf);
+
+ // the jmethodID
+ jmethodID method = jvf->method()->jmethod_id();
+
+ if (!(jvf->method()->is_native())) {
+ jlocation bci = (jlocation)jvf->bci();
+ StackValueCollection* locals = jvf->locals();
+ for (int slot=0; slot<locals->size(); slot++) {
+ if (locals->at(slot)->type() == T_OBJECT) {
+ oop o = locals->obj_at(slot)();
+ if (o == NULL) {
+ continue;
+ }
+
+ // stack reference
+ if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
+ bci, slot, o)) {
+ return false;
+ }
+ }
+ }
+
+ StackValueCollection* exprs = jvf->expressions();
+ for (int index=0; index < exprs->size(); index++) {
+ if (exprs->at(index)->type() == T_OBJECT) {
+ oop o = exprs->obj_at(index)();
+ if (o == NULL) {
+ continue;
+ }
+
+ // stack reference
+ if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
+ bci, locals->size() + index, o)) {
+ return false;
+ }
+ }
+ }
+
+ // Follow oops from compiled nmethod
+ if (jvf->cb() != NULL && jvf->cb()->is_nmethod()) {
+ blk->set_context(thread_tag, tid, depth, method);
+ jvf->cb()->as_nmethod()->oops_do(blk);
+ }
+ } else {
+ blk->set_context(thread_tag, tid, depth, method);
+ if (is_top_frame) {
+ // JNI locals for the top frame.
+ java_thread->active_handles()->oops_do(blk);
+ } else {
+ if (last_entry_frame != NULL) {
+ // JNI locals for the entry frame
+ assert(last_entry_frame->is_entry_frame(), "checking");
+ last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
+ }
+ }
+ }
+ last_entry_frame = NULL;
+ depth++;
+ } else {
+ // externalVFrame - for an entry frame then we report the JNI locals
+ // when we find the corresponding javaVFrame
+ frame* fr = vf->frame_pointer();
+ assert(fr != NULL, "sanity check");
+ if (fr->is_entry_frame()) {
+ last_entry_frame = fr;
+ }
+ }
+
+ vf = vf->sender();
+ is_top_frame = false;
+ }
+ } else {
+ // no last java frame but there may be JNI locals
+ blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
+ java_thread->active_handles()->oops_do(blk);
+ }
+ return true;
+}
+
+
+// Collects the simple roots for all threads and collects all
+// stack roots - for each thread it walks the execution
+// stack to find all references and local JNI refs.
+inline bool VM_HeapWalkOperation::collect_stack_roots() {
+ JNILocalRootsClosure blk;
+ for (JavaThread* thread = Threads::first(); thread != NULL ; thread = thread->next()) {
+ oop threadObj = thread->threadObj();
+ if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
+ // Collect the simple root for this thread before we
+ // collect its stack roots
+ if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
+ threadObj)) {
+ return false;
+ }
+ if (!collect_stack_roots(thread, &blk)) {
+ return false;
+ }
+ }
+ }
+ return true;
+}
+
+// visit an object
+// first mark the object as visited
+// second get all the outbound references from this object (in other words, all
+// the objects referenced by this object).
+//
+bool VM_HeapWalkOperation::visit(oop o) {
+ // mark object as visited
+ assert(!ObjectMarker::visited(o), "can't visit same object more than once");
+ ObjectMarker::mark(o);
+
+ // instance
+ if (o->is_instance()) {
+ if (o->klass() == SystemDictionary::Class_klass()) {
+ if (!java_lang_Class::is_primitive(o)) {
+ // a java.lang.Class
+ return iterate_over_class(o);
+ }
+ } else {
+ return iterate_over_object(o);
+ }
+ }
+
+ // object array
+ if (o->is_objArray()) {
+ return iterate_over_array(o);
+ }
+
+ // type array
+ if (o->is_typeArray()) {
+ return iterate_over_type_array(o);
+ }
+
+ return true;
+}
+
+void VM_HeapWalkOperation::doit() {
+ ResourceMark rm;
+ ObjectMarkerController marker;
+ ClassFieldMapCacheMark cm;
+
+ assert(visit_stack()->is_empty(), "visit stack must be empty");
+
+ // the heap walk starts with an initial object or the heap roots
+ if (initial_object().is_null()) {
+ // If either collect_stack_roots() or collect_simple_roots()
+ // returns false at this point, then there are no mark bits
+ // to reset.
+ ObjectMarker::set_needs_reset(false);
+
+ // Calling collect_stack_roots() before collect_simple_roots()
+ // can result in a big performance boost for an agent that is
+ // focused on analyzing references in the thread stacks.
+ if (!collect_stack_roots()) return;
+
+ if (!collect_simple_roots()) return;
+
+ // no early return so enable heap traversal to reset the mark bits
+ ObjectMarker::set_needs_reset(true);
+ } else {
+ visit_stack()->push(initial_object()());
+ }
+
+ // object references required
+ if (is_following_references()) {
+
+ // visit each object until all reachable objects have been
+ // visited or the callback asked to terminate the iteration.
+ while (!visit_stack()->is_empty()) {
+ oop o = visit_stack()->pop();
+ if (!ObjectMarker::visited(o)) {
+ if (!visit(o)) {
+ break;
+ }
+ }
+ }
+ }
+}
+
+// iterate over all objects that are reachable from a set of roots
+void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
+ jvmtiStackReferenceCallback stack_ref_callback,
+ jvmtiObjectReferenceCallback object_ref_callback,
+ const void* user_data) {
+ MutexLocker ml(Heap_lock);
+ BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
+ VM_HeapWalkOperation op(this, Handle(), context, user_data);
+ VMThread::execute(&op);
+}
+
+// iterate over all objects that are reachable from a given object
+void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
+ jvmtiObjectReferenceCallback object_ref_callback,
+ const void* user_data) {
+ oop obj = JNIHandles::resolve(object);
+ Handle initial_object(Thread::current(), obj);
+
+ MutexLocker ml(Heap_lock);
+ BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
+ VM_HeapWalkOperation op(this, initial_object, context, user_data);
+ VMThread::execute(&op);
+}
+
+// follow references from an initial object or the GC roots
+void JvmtiTagMap::follow_references(jint heap_filter,
+ Klass* klass,
+ jobject object,
+ const jvmtiHeapCallbacks* callbacks,
+ const void* user_data)
+{
+ oop obj = JNIHandles::resolve(object);
+ Handle initial_object(Thread::current(), obj);
+
+ MutexLocker ml(Heap_lock);
+ AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
+ VM_HeapWalkOperation op(this, initial_object, context, user_data);
+ VMThread::execute(&op);
+}
+
+
+void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
+ // No locks during VM bring-up (0 threads) and no safepoints after main
+ // thread creation and before VMThread creation (1 thread); initial GC
+ // verification can happen in that window which gets to here.
+ assert(Threads::number_of_threads() <= 1 ||
+ SafepointSynchronize::is_at_safepoint(),
+ "must be executed at a safepoint");
+ if (JvmtiEnv::environments_might_exist()) {
+ JvmtiEnvIterator it;
+ for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
+ JvmtiTagMap* tag_map = env->tag_map();
+ if (tag_map != NULL && !tag_map->is_empty()) {
+ tag_map->do_weak_oops(is_alive, f);
+ }
+ }
+ }
+}
+
+void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
+
+ // does this environment have the OBJECT_FREE event enabled
+ bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE);
+
+ // counters used for trace message
+ int freed = 0;
+ int moved = 0;
+
+ JvmtiTagHashmap* hashmap = this->hashmap();
+
+ // reenable sizing (if disabled)
+ hashmap->set_resizing_enabled(true);
+
+ // if the hashmap is empty then we can skip it
+ if (hashmap->_entry_count == 0) {
+ return;
+ }
+
+ // now iterate through each entry in the table
+
+ JvmtiTagHashmapEntry** table = hashmap->table();
+ int size = hashmap->size();
+
+ JvmtiTagHashmapEntry* delayed_add = NULL;
+
+ for (int pos = 0; pos < size; ++pos) {
+ JvmtiTagHashmapEntry* entry = table[pos];
+ JvmtiTagHashmapEntry* prev = NULL;
+
+ while (entry != NULL) {
+ JvmtiTagHashmapEntry* next = entry->next();
+
+ oop* obj = entry->object_addr();
+
+ // has object been GC'ed
+ if (!is_alive->do_object_b(entry->object())) {
+ // grab the tag
+ jlong tag = entry->tag();
+ guarantee(tag != 0, "checking");
+
+ // remove GC'ed entry from hashmap and return the
+ // entry to the free list
+ hashmap->remove(prev, pos, entry);
+ destroy_entry(entry);
+
+ // post the event to the profiler
+ if (post_object_free) {
+ JvmtiExport::post_object_free(env(), tag);
+ }
+
+ ++freed;
+ } else {
+ f->do_oop(entry->object_addr());
+ oop new_oop = entry->object();
+
+ // if the object has moved then re-hash it and move its
+ // entry to its new location.
+ unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size);
+ if (new_pos != (unsigned int)pos) {
+ if (prev == NULL) {
+ table[pos] = next;
+ } else {
+ prev->set_next(next);
+ }
+ if (new_pos < (unsigned int)pos) {
+ entry->set_next(table[new_pos]);
+ table[new_pos] = entry;
+ } else {
+ // Delay adding this entry to it's new position as we'd end up
+ // hitting it again during this iteration.
+ entry->set_next(delayed_add);
+ delayed_add = entry;
+ }
+ moved++;
+ } else {
+ // object didn't move
+ prev = entry;
+ }
+ }
+
+ entry = next;
+ }
+ }
+
+ // Re-add all the entries which were kept aside
+ while (delayed_add != NULL) {
+ JvmtiTagHashmapEntry* next = delayed_add->next();
+ unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object(), size);
+ delayed_add->set_next(table[pos]);
+ table[pos] = delayed_add;
+ delayed_add = next;
+ }
+
+ log_debug(jvmti, objecttagging)("(%d->%d, %d freed, %d total moves)",
+ hashmap->_entry_count + freed, hashmap->_entry_count, freed, moved);
+}