1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/prims/jvmtiTagMap.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,3380 @@
1.4 +/*
1.5 + * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "classfile/symbolTable.hpp"
1.30 +#include "classfile/systemDictionary.hpp"
1.31 +#include "classfile/vmSymbols.hpp"
1.32 +#include "jvmtifiles/jvmtiEnv.hpp"
1.33 +#include "oops/instanceMirrorKlass.hpp"
1.34 +#include "oops/objArrayKlass.hpp"
1.35 +#include "oops/oop.inline2.hpp"
1.36 +#include "prims/jvmtiEventController.hpp"
1.37 +#include "prims/jvmtiEventController.inline.hpp"
1.38 +#include "prims/jvmtiExport.hpp"
1.39 +#include "prims/jvmtiImpl.hpp"
1.40 +#include "prims/jvmtiTagMap.hpp"
1.41 +#include "runtime/biasedLocking.hpp"
1.42 +#include "runtime/javaCalls.hpp"
1.43 +#include "runtime/jniHandles.hpp"
1.44 +#include "runtime/mutex.hpp"
1.45 +#include "runtime/mutexLocker.hpp"
1.46 +#include "runtime/reflectionUtils.hpp"
1.47 +#include "runtime/vframe.hpp"
1.48 +#include "runtime/vmThread.hpp"
1.49 +#include "runtime/vm_operations.hpp"
1.50 +#include "services/serviceUtil.hpp"
1.51 +#include "utilities/macros.hpp"
1.52 +#if INCLUDE_ALL_GCS
1.53 +#include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
1.54 +#endif // INCLUDE_ALL_GCS
1.55 +
1.56 +// JvmtiTagHashmapEntry
1.57 +//
1.58 +// Each entry encapsulates a reference to the tagged object
1.59 +// and the tag value. In addition an entry includes a next pointer which
1.60 +// is used to chain entries together.
1.61 +
1.62 +class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
1.63 + private:
1.64 + friend class JvmtiTagMap;
1.65 +
1.66 + oop _object; // tagged object
1.67 + jlong _tag; // the tag
1.68 + JvmtiTagHashmapEntry* _next; // next on the list
1.69 +
1.70 + inline void init(oop object, jlong tag) {
1.71 + _object = object;
1.72 + _tag = tag;
1.73 + _next = NULL;
1.74 + }
1.75 +
1.76 + // constructor
1.77 + JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
1.78 +
1.79 + public:
1.80 +
1.81 + // accessor methods
1.82 + inline oop object() const { return _object; }
1.83 + inline oop* object_addr() { return &_object; }
1.84 + inline jlong tag() const { return _tag; }
1.85 +
1.86 + inline void set_tag(jlong tag) {
1.87 + assert(tag != 0, "can't be zero");
1.88 + _tag = tag;
1.89 + }
1.90 +
1.91 + inline JvmtiTagHashmapEntry* next() const { return _next; }
1.92 + inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
1.93 +};
1.94 +
1.95 +
1.96 +// JvmtiTagHashmap
1.97 +//
1.98 +// A hashmap is essentially a table of pointers to entries. Entries
1.99 +// are hashed to a location, or position in the table, and then
1.100 +// chained from that location. The "key" for hashing is address of
1.101 +// the object, or oop. The "value" is the tag value.
1.102 +//
1.103 +// A hashmap maintains a count of the number entries in the hashmap
1.104 +// and resizes if the number of entries exceeds a given threshold.
1.105 +// The threshold is specified as a percentage of the size - for
1.106 +// example a threshold of 0.75 will trigger the hashmap to resize
1.107 +// if the number of entries is >75% of table size.
1.108 +//
1.109 +// A hashmap provides functions for adding, removing, and finding
1.110 +// entries. It also provides a function to iterate over all entries
1.111 +// in the hashmap.
1.112 +
1.113 +class JvmtiTagHashmap : public CHeapObj<mtInternal> {
1.114 + private:
1.115 + friend class JvmtiTagMap;
1.116 +
1.117 + enum {
1.118 + small_trace_threshold = 10000, // threshold for tracing
1.119 + medium_trace_threshold = 100000,
1.120 + large_trace_threshold = 1000000,
1.121 + initial_trace_threshold = small_trace_threshold
1.122 + };
1.123 +
1.124 + static int _sizes[]; // array of possible hashmap sizes
1.125 + int _size; // actual size of the table
1.126 + int _size_index; // index into size table
1.127 +
1.128 + int _entry_count; // number of entries in the hashmap
1.129 +
1.130 + float _load_factor; // load factor as a % of the size
1.131 + int _resize_threshold; // computed threshold to trigger resizing.
1.132 + bool _resizing_enabled; // indicates if hashmap can resize
1.133 +
1.134 + int _trace_threshold; // threshold for trace messages
1.135 +
1.136 + JvmtiTagHashmapEntry** _table; // the table of entries.
1.137 +
1.138 + // private accessors
1.139 + int resize_threshold() const { return _resize_threshold; }
1.140 + int trace_threshold() const { return _trace_threshold; }
1.141 +
1.142 + // initialize the hashmap
1.143 + void init(int size_index=0, float load_factor=4.0f) {
1.144 + int initial_size = _sizes[size_index];
1.145 + _size_index = size_index;
1.146 + _size = initial_size;
1.147 + _entry_count = 0;
1.148 + if (TraceJVMTIObjectTagging) {
1.149 + _trace_threshold = initial_trace_threshold;
1.150 + } else {
1.151 + _trace_threshold = -1;
1.152 + }
1.153 + _load_factor = load_factor;
1.154 + _resize_threshold = (int)(_load_factor * _size);
1.155 + _resizing_enabled = true;
1.156 + size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*);
1.157 + _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
1.158 + if (_table == NULL) {
1.159 + vm_exit_out_of_memory(s, OOM_MALLOC_ERROR,
1.160 + "unable to allocate initial hashtable for jvmti object tags");
1.161 + }
1.162 + for (int i=0; i<initial_size; i++) {
1.163 + _table[i] = NULL;
1.164 + }
1.165 + }
1.166 +
1.167 + // hash a given key (oop) with the specified size
1.168 + static unsigned int hash(oop key, int size) {
1.169 + // shift right to get better distribution (as these bits will be zero
1.170 + // with aligned addresses)
1.171 + unsigned int addr = (unsigned int)(cast_from_oop<intptr_t>(key));
1.172 +#ifdef _LP64
1.173 + return (addr >> 3) % size;
1.174 +#else
1.175 + return (addr >> 2) % size;
1.176 +#endif
1.177 + }
1.178 +
1.179 + // hash a given key (oop)
1.180 + unsigned int hash(oop key) {
1.181 + return hash(key, _size);
1.182 + }
1.183 +
1.184 + // resize the hashmap - allocates a large table and re-hashes
1.185 + // all entries into the new table.
1.186 + void resize() {
1.187 + int new_size_index = _size_index+1;
1.188 + int new_size = _sizes[new_size_index];
1.189 + if (new_size < 0) {
1.190 + // hashmap already at maximum capacity
1.191 + return;
1.192 + }
1.193 +
1.194 + // allocate new table
1.195 + size_t s = new_size * sizeof(JvmtiTagHashmapEntry*);
1.196 + JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
1.197 + if (new_table == NULL) {
1.198 + warning("unable to allocate larger hashtable for jvmti object tags");
1.199 + set_resizing_enabled(false);
1.200 + return;
1.201 + }
1.202 +
1.203 + // initialize new table
1.204 + int i;
1.205 + for (i=0; i<new_size; i++) {
1.206 + new_table[i] = NULL;
1.207 + }
1.208 +
1.209 + // rehash all entries into the new table
1.210 + for (i=0; i<_size; i++) {
1.211 + JvmtiTagHashmapEntry* entry = _table[i];
1.212 + while (entry != NULL) {
1.213 + JvmtiTagHashmapEntry* next = entry->next();
1.214 + oop key = entry->object();
1.215 + assert(key != NULL, "jni weak reference cleared!!");
1.216 + unsigned int h = hash(key, new_size);
1.217 + JvmtiTagHashmapEntry* anchor = new_table[h];
1.218 + if (anchor == NULL) {
1.219 + new_table[h] = entry;
1.220 + entry->set_next(NULL);
1.221 + } else {
1.222 + entry->set_next(anchor);
1.223 + new_table[h] = entry;
1.224 + }
1.225 + entry = next;
1.226 + }
1.227 + }
1.228 +
1.229 + // free old table and update settings.
1.230 + os::free((void*)_table);
1.231 + _table = new_table;
1.232 + _size_index = new_size_index;
1.233 + _size = new_size;
1.234 +
1.235 + // compute new resize threshold
1.236 + _resize_threshold = (int)(_load_factor * _size);
1.237 + }
1.238 +
1.239 +
1.240 + // internal remove function - remove an entry at a given position in the
1.241 + // table.
1.242 + inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) {
1.243 + assert(pos >= 0 && pos < _size, "out of range");
1.244 + if (prev == NULL) {
1.245 + _table[pos] = entry->next();
1.246 + } else {
1.247 + prev->set_next(entry->next());
1.248 + }
1.249 + assert(_entry_count > 0, "checking");
1.250 + _entry_count--;
1.251 + }
1.252 +
1.253 + // resizing switch
1.254 + bool is_resizing_enabled() const { return _resizing_enabled; }
1.255 + void set_resizing_enabled(bool enable) { _resizing_enabled = enable; }
1.256 +
1.257 + // debugging
1.258 + void print_memory_usage();
1.259 + void compute_next_trace_threshold();
1.260 +
1.261 + public:
1.262 +
1.263 + // create a JvmtiTagHashmap of a preferred size and optionally a load factor.
1.264 + // The preferred size is rounded down to an actual size.
1.265 + JvmtiTagHashmap(int size, float load_factor=0.0f) {
1.266 + int i=0;
1.267 + while (_sizes[i] < size) {
1.268 + if (_sizes[i] < 0) {
1.269 + assert(i > 0, "sanity check");
1.270 + i--;
1.271 + break;
1.272 + }
1.273 + i++;
1.274 + }
1.275 +
1.276 + // if a load factor is specified then use it, otherwise use default
1.277 + if (load_factor > 0.01f) {
1.278 + init(i, load_factor);
1.279 + } else {
1.280 + init(i);
1.281 + }
1.282 + }
1.283 +
1.284 + // create a JvmtiTagHashmap with default settings
1.285 + JvmtiTagHashmap() {
1.286 + init();
1.287 + }
1.288 +
1.289 + // release table when JvmtiTagHashmap destroyed
1.290 + ~JvmtiTagHashmap() {
1.291 + if (_table != NULL) {
1.292 + os::free((void*)_table);
1.293 + _table = NULL;
1.294 + }
1.295 + }
1.296 +
1.297 + // accessors
1.298 + int size() const { return _size; }
1.299 + JvmtiTagHashmapEntry** table() const { return _table; }
1.300 + int entry_count() const { return _entry_count; }
1.301 +
1.302 + // find an entry in the hashmap, returns NULL if not found.
1.303 + inline JvmtiTagHashmapEntry* find(oop key) {
1.304 + unsigned int h = hash(key);
1.305 + JvmtiTagHashmapEntry* entry = _table[h];
1.306 + while (entry != NULL) {
1.307 + if (entry->object() == key) {
1.308 + return entry;
1.309 + }
1.310 + entry = entry->next();
1.311 + }
1.312 + return NULL;
1.313 + }
1.314 +
1.315 +
1.316 + // add a new entry to hashmap
1.317 + inline void add(oop key, JvmtiTagHashmapEntry* entry) {
1.318 + assert(key != NULL, "checking");
1.319 + assert(find(key) == NULL, "duplicate detected");
1.320 + unsigned int h = hash(key);
1.321 + JvmtiTagHashmapEntry* anchor = _table[h];
1.322 + if (anchor == NULL) {
1.323 + _table[h] = entry;
1.324 + entry->set_next(NULL);
1.325 + } else {
1.326 + entry->set_next(anchor);
1.327 + _table[h] = entry;
1.328 + }
1.329 +
1.330 + _entry_count++;
1.331 + if (trace_threshold() > 0 && entry_count() >= trace_threshold()) {
1.332 + assert(TraceJVMTIObjectTagging, "should only get here when tracing");
1.333 + print_memory_usage();
1.334 + compute_next_trace_threshold();
1.335 + }
1.336 +
1.337 + // if the number of entries exceed the threshold then resize
1.338 + if (entry_count() > resize_threshold() && is_resizing_enabled()) {
1.339 + resize();
1.340 + }
1.341 + }
1.342 +
1.343 + // remove an entry with the given key.
1.344 + inline JvmtiTagHashmapEntry* remove(oop key) {
1.345 + unsigned int h = hash(key);
1.346 + JvmtiTagHashmapEntry* entry = _table[h];
1.347 + JvmtiTagHashmapEntry* prev = NULL;
1.348 + while (entry != NULL) {
1.349 + if (key == entry->object()) {
1.350 + break;
1.351 + }
1.352 + prev = entry;
1.353 + entry = entry->next();
1.354 + }
1.355 + if (entry != NULL) {
1.356 + remove(prev, h, entry);
1.357 + }
1.358 + return entry;
1.359 + }
1.360 +
1.361 + // iterate over all entries in the hashmap
1.362 + void entry_iterate(JvmtiTagHashmapEntryClosure* closure);
1.363 +};
1.364 +
1.365 +// possible hashmap sizes - odd primes that roughly double in size.
1.366 +// To avoid excessive resizing the odd primes from 4801-76831 and
1.367 +// 76831-307261 have been removed. The list must be terminated by -1.
1.368 +int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891,
1.369 + 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 };
1.370 +
1.371 +
1.372 +// A supporting class for iterating over all entries in Hashmap
1.373 +class JvmtiTagHashmapEntryClosure {
1.374 + public:
1.375 + virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0;
1.376 +};
1.377 +
1.378 +
1.379 +// iterate over all entries in the hashmap
1.380 +void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
1.381 + for (int i=0; i<_size; i++) {
1.382 + JvmtiTagHashmapEntry* entry = _table[i];
1.383 + JvmtiTagHashmapEntry* prev = NULL;
1.384 + while (entry != NULL) {
1.385 + // obtain the next entry before invoking do_entry - this is
1.386 + // necessary because do_entry may remove the entry from the
1.387 + // hashmap.
1.388 + JvmtiTagHashmapEntry* next = entry->next();
1.389 + closure->do_entry(entry);
1.390 + entry = next;
1.391 + }
1.392 + }
1.393 +}
1.394 +
1.395 +// debugging
1.396 +void JvmtiTagHashmap::print_memory_usage() {
1.397 + intptr_t p = (intptr_t)this;
1.398 + tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p);
1.399 +
1.400 + // table + entries in KB
1.401 + int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) +
1.402 + entry_count()*sizeof(JvmtiTagHashmapEntry))/K;
1.403 +
1.404 + int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K);
1.405 + tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]",
1.406 + entry_count(), hashmap_usage, weak_globals_usage);
1.407 +}
1.408 +
1.409 +// compute threshold for the next trace message
1.410 +void JvmtiTagHashmap::compute_next_trace_threshold() {
1.411 + if (trace_threshold() < medium_trace_threshold) {
1.412 + _trace_threshold += small_trace_threshold;
1.413 + } else {
1.414 + if (trace_threshold() < large_trace_threshold) {
1.415 + _trace_threshold += medium_trace_threshold;
1.416 + } else {
1.417 + _trace_threshold += large_trace_threshold;
1.418 + }
1.419 + }
1.420 +}
1.421 +
1.422 +// create a JvmtiTagMap
1.423 +JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
1.424 + _env(env),
1.425 + _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false),
1.426 + _free_entries(NULL),
1.427 + _free_entries_count(0)
1.428 +{
1.429 + assert(JvmtiThreadState_lock->is_locked(), "sanity check");
1.430 + assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
1.431 +
1.432 + _hashmap = new JvmtiTagHashmap();
1.433 +
1.434 + // finally add us to the environment
1.435 + ((JvmtiEnvBase *)env)->set_tag_map(this);
1.436 +}
1.437 +
1.438 +
1.439 +// destroy a JvmtiTagMap
1.440 +JvmtiTagMap::~JvmtiTagMap() {
1.441 +
1.442 + // no lock acquired as we assume the enclosing environment is
1.443 + // also being destroryed.
1.444 + ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
1.445 +
1.446 + JvmtiTagHashmapEntry** table = _hashmap->table();
1.447 + for (int j = 0; j < _hashmap->size(); j++) {
1.448 + JvmtiTagHashmapEntry* entry = table[j];
1.449 + while (entry != NULL) {
1.450 + JvmtiTagHashmapEntry* next = entry->next();
1.451 + delete entry;
1.452 + entry = next;
1.453 + }
1.454 + }
1.455 +
1.456 + // finally destroy the hashmap
1.457 + delete _hashmap;
1.458 + _hashmap = NULL;
1.459 +
1.460 + // remove any entries on the free list
1.461 + JvmtiTagHashmapEntry* entry = _free_entries;
1.462 + while (entry != NULL) {
1.463 + JvmtiTagHashmapEntry* next = entry->next();
1.464 + delete entry;
1.465 + entry = next;
1.466 + }
1.467 + _free_entries = NULL;
1.468 +}
1.469 +
1.470 +// create a hashmap entry
1.471 +// - if there's an entry on the (per-environment) free list then this
1.472 +// is returned. Otherwise an new entry is allocated.
1.473 +JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) {
1.474 + assert(Thread::current()->is_VM_thread() || is_locked(), "checking");
1.475 + JvmtiTagHashmapEntry* entry;
1.476 + if (_free_entries == NULL) {
1.477 + entry = new JvmtiTagHashmapEntry(ref, tag);
1.478 + } else {
1.479 + assert(_free_entries_count > 0, "mismatched _free_entries_count");
1.480 + _free_entries_count--;
1.481 + entry = _free_entries;
1.482 + _free_entries = entry->next();
1.483 + entry->init(ref, tag);
1.484 + }
1.485 + return entry;
1.486 +}
1.487 +
1.488 +// destroy an entry by returning it to the free list
1.489 +void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
1.490 + assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
1.491 + // limit the size of the free list
1.492 + if (_free_entries_count >= max_free_entries) {
1.493 + delete entry;
1.494 + } else {
1.495 + entry->set_next(_free_entries);
1.496 + _free_entries = entry;
1.497 + _free_entries_count++;
1.498 + }
1.499 +}
1.500 +
1.501 +// returns the tag map for the given environments. If the tag map
1.502 +// doesn't exist then it is created.
1.503 +JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
1.504 + JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map();
1.505 + if (tag_map == NULL) {
1.506 + MutexLocker mu(JvmtiThreadState_lock);
1.507 + tag_map = ((JvmtiEnvBase*)env)->tag_map();
1.508 + if (tag_map == NULL) {
1.509 + tag_map = new JvmtiTagMap(env);
1.510 + }
1.511 + } else {
1.512 + CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
1.513 + }
1.514 + return tag_map;
1.515 +}
1.516 +
1.517 +// iterate over all entries in the tag map.
1.518 +void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
1.519 + hashmap()->entry_iterate(closure);
1.520 +}
1.521 +
1.522 +// returns true if the hashmaps are empty
1.523 +bool JvmtiTagMap::is_empty() {
1.524 + assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
1.525 + return hashmap()->entry_count() == 0;
1.526 +}
1.527 +
1.528 +
1.529 +// Return the tag value for an object, or 0 if the object is
1.530 +// not tagged
1.531 +//
1.532 +static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
1.533 + JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o);
1.534 + if (entry == NULL) {
1.535 + return 0;
1.536 + } else {
1.537 + return entry->tag();
1.538 + }
1.539 +}
1.540 +
1.541 +
1.542 +// A CallbackWrapper is a support class for querying and tagging an object
1.543 +// around a callback to a profiler. The constructor does pre-callback
1.544 +// work to get the tag value, klass tag value, ... and the destructor
1.545 +// does the post-callback work of tagging or untagging the object.
1.546 +//
1.547 +// {
1.548 +// CallbackWrapper wrapper(tag_map, o);
1.549 +//
1.550 +// (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
1.551 +//
1.552 +// } // wrapper goes out of scope here which results in the destructor
1.553 +// checking to see if the object has been tagged, untagged, or the
1.554 +// tag value has changed.
1.555 +//
1.556 +class CallbackWrapper : public StackObj {
1.557 + private:
1.558 + JvmtiTagMap* _tag_map;
1.559 + JvmtiTagHashmap* _hashmap;
1.560 + JvmtiTagHashmapEntry* _entry;
1.561 + oop _o;
1.562 + jlong _obj_size;
1.563 + jlong _obj_tag;
1.564 + jlong _klass_tag;
1.565 +
1.566 + protected:
1.567 + JvmtiTagMap* tag_map() const { return _tag_map; }
1.568 +
1.569 + // invoked post-callback to tag, untag, or update the tag of an object
1.570 + void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap,
1.571 + JvmtiTagHashmapEntry* entry, jlong obj_tag);
1.572 + public:
1.573 + CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
1.574 + assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
1.575 + "MT unsafe or must be VM thread");
1.576 +
1.577 + // object to tag
1.578 + _o = o;
1.579 +
1.580 + // object size
1.581 + _obj_size = (jlong)_o->size() * wordSize;
1.582 +
1.583 + // record the context
1.584 + _tag_map = tag_map;
1.585 + _hashmap = tag_map->hashmap();
1.586 + _entry = _hashmap->find(_o);
1.587 +
1.588 + // get object tag
1.589 + _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
1.590 +
1.591 + // get the class and the class's tag value
1.592 + assert(SystemDictionary::Class_klass()->oop_is_instanceMirror(), "Is not?");
1.593 +
1.594 + _klass_tag = tag_for(tag_map, _o->klass()->java_mirror());
1.595 + }
1.596 +
1.597 + ~CallbackWrapper() {
1.598 + post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
1.599 + }
1.600 +
1.601 + inline jlong* obj_tag_p() { return &_obj_tag; }
1.602 + inline jlong obj_size() const { return _obj_size; }
1.603 + inline jlong obj_tag() const { return _obj_tag; }
1.604 + inline jlong klass_tag() const { return _klass_tag; }
1.605 +};
1.606 +
1.607 +
1.608 +
1.609 +// callback post-callback to tag, untag, or update the tag of an object
1.610 +void inline CallbackWrapper::post_callback_tag_update(oop o,
1.611 + JvmtiTagHashmap* hashmap,
1.612 + JvmtiTagHashmapEntry* entry,
1.613 + jlong obj_tag) {
1.614 + if (entry == NULL) {
1.615 + if (obj_tag != 0) {
1.616 + // callback has tagged the object
1.617 + assert(Thread::current()->is_VM_thread(), "must be VMThread");
1.618 + entry = tag_map()->create_entry(o, obj_tag);
1.619 + hashmap->add(o, entry);
1.620 + }
1.621 + } else {
1.622 + // object was previously tagged - the callback may have untagged
1.623 + // the object or changed the tag value
1.624 + if (obj_tag == 0) {
1.625 +
1.626 + JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o);
1.627 + assert(entry_removed == entry, "checking");
1.628 + tag_map()->destroy_entry(entry);
1.629 +
1.630 + } else {
1.631 + if (obj_tag != entry->tag()) {
1.632 + entry->set_tag(obj_tag);
1.633 + }
1.634 + }
1.635 + }
1.636 +}
1.637 +
1.638 +// An extended CallbackWrapper used when reporting an object reference
1.639 +// to the agent.
1.640 +//
1.641 +// {
1.642 +// TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
1.643 +//
1.644 +// (*callback)(wrapper.klass_tag(),
1.645 +// wrapper.obj_size(),
1.646 +// wrapper.obj_tag_p()
1.647 +// wrapper.referrer_tag_p(), ...)
1.648 +//
1.649 +// } // wrapper goes out of scope here which results in the destructor
1.650 +// checking to see if the referrer object has been tagged, untagged,
1.651 +// or the tag value has changed.
1.652 +//
1.653 +class TwoOopCallbackWrapper : public CallbackWrapper {
1.654 + private:
1.655 + bool _is_reference_to_self;
1.656 + JvmtiTagHashmap* _referrer_hashmap;
1.657 + JvmtiTagHashmapEntry* _referrer_entry;
1.658 + oop _referrer;
1.659 + jlong _referrer_obj_tag;
1.660 + jlong _referrer_klass_tag;
1.661 + jlong* _referrer_tag_p;
1.662 +
1.663 + bool is_reference_to_self() const { return _is_reference_to_self; }
1.664 +
1.665 + public:
1.666 + TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
1.667 + CallbackWrapper(tag_map, o)
1.668 + {
1.669 + // self reference needs to be handled in a special way
1.670 + _is_reference_to_self = (referrer == o);
1.671 +
1.672 + if (_is_reference_to_self) {
1.673 + _referrer_klass_tag = klass_tag();
1.674 + _referrer_tag_p = obj_tag_p();
1.675 + } else {
1.676 + _referrer = referrer;
1.677 + // record the context
1.678 + _referrer_hashmap = tag_map->hashmap();
1.679 + _referrer_entry = _referrer_hashmap->find(_referrer);
1.680 +
1.681 + // get object tag
1.682 + _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
1.683 + _referrer_tag_p = &_referrer_obj_tag;
1.684 +
1.685 + // get referrer class tag.
1.686 + _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror());
1.687 + }
1.688 + }
1.689 +
1.690 + ~TwoOopCallbackWrapper() {
1.691 + if (!is_reference_to_self()){
1.692 + post_callback_tag_update(_referrer,
1.693 + _referrer_hashmap,
1.694 + _referrer_entry,
1.695 + _referrer_obj_tag);
1.696 + }
1.697 + }
1.698 +
1.699 + // address of referrer tag
1.700 + // (for a self reference this will return the same thing as obj_tag_p())
1.701 + inline jlong* referrer_tag_p() { return _referrer_tag_p; }
1.702 +
1.703 + // referrer's class tag
1.704 + inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
1.705 +};
1.706 +
1.707 +// tag an object
1.708 +//
1.709 +// This function is performance critical. If many threads attempt to tag objects
1.710 +// around the same time then it's possible that the Mutex associated with the
1.711 +// tag map will be a hot lock.
1.712 +void JvmtiTagMap::set_tag(jobject object, jlong tag) {
1.713 + MutexLocker ml(lock());
1.714 +
1.715 + // resolve the object
1.716 + oop o = JNIHandles::resolve_non_null(object);
1.717 +
1.718 + // see if the object is already tagged
1.719 + JvmtiTagHashmap* hashmap = _hashmap;
1.720 + JvmtiTagHashmapEntry* entry = hashmap->find(o);
1.721 +
1.722 + // if the object is not already tagged then we tag it
1.723 + if (entry == NULL) {
1.724 + if (tag != 0) {
1.725 + entry = create_entry(o, tag);
1.726 + hashmap->add(o, entry);
1.727 + } else {
1.728 + // no-op
1.729 + }
1.730 + } else {
1.731 + // if the object is already tagged then we either update
1.732 + // the tag (if a new tag value has been provided)
1.733 + // or remove the object if the new tag value is 0.
1.734 + if (tag == 0) {
1.735 + hashmap->remove(o);
1.736 + destroy_entry(entry);
1.737 + } else {
1.738 + entry->set_tag(tag);
1.739 + }
1.740 + }
1.741 +}
1.742 +
1.743 +// get the tag for an object
1.744 +jlong JvmtiTagMap::get_tag(jobject object) {
1.745 + MutexLocker ml(lock());
1.746 +
1.747 + // resolve the object
1.748 + oop o = JNIHandles::resolve_non_null(object);
1.749 +
1.750 + return tag_for(this, o);
1.751 +}
1.752 +
1.753 +
1.754 +// Helper class used to describe the static or instance fields of a class.
1.755 +// For each field it holds the field index (as defined by the JVMTI specification),
1.756 +// the field type, and the offset.
1.757 +
1.758 +class ClassFieldDescriptor: public CHeapObj<mtInternal> {
1.759 + private:
1.760 + int _field_index;
1.761 + int _field_offset;
1.762 + char _field_type;
1.763 + public:
1.764 + ClassFieldDescriptor(int index, char type, int offset) :
1.765 + _field_index(index), _field_type(type), _field_offset(offset) {
1.766 + }
1.767 + int field_index() const { return _field_index; }
1.768 + char field_type() const { return _field_type; }
1.769 + int field_offset() const { return _field_offset; }
1.770 +};
1.771 +
1.772 +class ClassFieldMap: public CHeapObj<mtInternal> {
1.773 + private:
1.774 + enum {
1.775 + initial_field_count = 5
1.776 + };
1.777 +
1.778 + // list of field descriptors
1.779 + GrowableArray<ClassFieldDescriptor*>* _fields;
1.780 +
1.781 + // constructor
1.782 + ClassFieldMap();
1.783 +
1.784 + // add a field
1.785 + void add(int index, char type, int offset);
1.786 +
1.787 + // returns the field count for the given class
1.788 + static int compute_field_count(instanceKlassHandle ikh);
1.789 +
1.790 + public:
1.791 + ~ClassFieldMap();
1.792 +
1.793 + // access
1.794 + int field_count() { return _fields->length(); }
1.795 + ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
1.796 +
1.797 + // functions to create maps of static or instance fields
1.798 + static ClassFieldMap* create_map_of_static_fields(Klass* k);
1.799 + static ClassFieldMap* create_map_of_instance_fields(oop obj);
1.800 +};
1.801 +
1.802 +ClassFieldMap::ClassFieldMap() {
1.803 + _fields = new (ResourceObj::C_HEAP, mtInternal)
1.804 + GrowableArray<ClassFieldDescriptor*>(initial_field_count, true);
1.805 +}
1.806 +
1.807 +ClassFieldMap::~ClassFieldMap() {
1.808 + for (int i=0; i<_fields->length(); i++) {
1.809 + delete _fields->at(i);
1.810 + }
1.811 + delete _fields;
1.812 +}
1.813 +
1.814 +void ClassFieldMap::add(int index, char type, int offset) {
1.815 + ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
1.816 + _fields->append(field);
1.817 +}
1.818 +
1.819 +// Returns a heap allocated ClassFieldMap to describe the static fields
1.820 +// of the given class.
1.821 +//
1.822 +ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
1.823 + HandleMark hm;
1.824 + instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);
1.825 +
1.826 + // create the field map
1.827 + ClassFieldMap* field_map = new ClassFieldMap();
1.828 +
1.829 + FilteredFieldStream f(ikh, false, false);
1.830 + int max_field_index = f.field_count()-1;
1.831 +
1.832 + int index = 0;
1.833 + for (FilteredFieldStream fld(ikh, true, true); !fld.eos(); fld.next(), index++) {
1.834 + // ignore instance fields
1.835 + if (!fld.access_flags().is_static()) {
1.836 + continue;
1.837 + }
1.838 + field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
1.839 + }
1.840 + return field_map;
1.841 +}
1.842 +
1.843 +// Returns a heap allocated ClassFieldMap to describe the instance fields
1.844 +// of the given class. All instance fields are included (this means public
1.845 +// and private fields declared in superclasses and superinterfaces too).
1.846 +//
1.847 +ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
1.848 + HandleMark hm;
1.849 + instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), obj->klass());
1.850 +
1.851 + // create the field map
1.852 + ClassFieldMap* field_map = new ClassFieldMap();
1.853 +
1.854 + FilteredFieldStream f(ikh, false, false);
1.855 +
1.856 + int max_field_index = f.field_count()-1;
1.857 +
1.858 + int index = 0;
1.859 + for (FilteredFieldStream fld(ikh, false, false); !fld.eos(); fld.next(), index++) {
1.860 + // ignore static fields
1.861 + if (fld.access_flags().is_static()) {
1.862 + continue;
1.863 + }
1.864 + field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
1.865 + }
1.866 +
1.867 + return field_map;
1.868 +}
1.869 +
1.870 +// Helper class used to cache a ClassFileMap for the instance fields of
1.871 +// a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
1.872 +// heap iteration and avoid creating a field map for each object in the heap
1.873 +// (only need to create the map when the first instance of a class is encountered).
1.874 +//
1.875 +class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
1.876 + private:
1.877 + enum {
1.878 + initial_class_count = 200
1.879 + };
1.880 + ClassFieldMap* _field_map;
1.881 +
1.882 + ClassFieldMap* field_map() const { return _field_map; }
1.883 +
1.884 + JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
1.885 + ~JvmtiCachedClassFieldMap();
1.886 +
1.887 + static GrowableArray<InstanceKlass*>* _class_list;
1.888 + static void add_to_class_list(InstanceKlass* ik);
1.889 +
1.890 + public:
1.891 + // returns the field map for a given object (returning map cached
1.892 + // by InstanceKlass if possible
1.893 + static ClassFieldMap* get_map_of_instance_fields(oop obj);
1.894 +
1.895 + // removes the field map from all instanceKlasses - should be
1.896 + // called before VM operation completes
1.897 + static void clear_cache();
1.898 +
1.899 + // returns the number of ClassFieldMap cached by instanceKlasses
1.900 + static int cached_field_map_count();
1.901 +};
1.902 +
1.903 +GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
1.904 +
1.905 +JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
1.906 + _field_map = field_map;
1.907 +}
1.908 +
1.909 +JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
1.910 + if (_field_map != NULL) {
1.911 + delete _field_map;
1.912 + }
1.913 +}
1.914 +
1.915 +// Marker class to ensure that the class file map cache is only used in a defined
1.916 +// scope.
1.917 +class ClassFieldMapCacheMark : public StackObj {
1.918 + private:
1.919 + static bool _is_active;
1.920 + public:
1.921 + ClassFieldMapCacheMark() {
1.922 + assert(Thread::current()->is_VM_thread(), "must be VMThread");
1.923 + assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
1.924 + assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
1.925 + _is_active = true;
1.926 + }
1.927 + ~ClassFieldMapCacheMark() {
1.928 + JvmtiCachedClassFieldMap::clear_cache();
1.929 + _is_active = false;
1.930 + }
1.931 + static bool is_active() { return _is_active; }
1.932 +};
1.933 +
1.934 +bool ClassFieldMapCacheMark::_is_active;
1.935 +
1.936 +
1.937 +// record that the given InstanceKlass is caching a field map
1.938 +void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
1.939 + if (_class_list == NULL) {
1.940 + _class_list = new (ResourceObj::C_HEAP, mtInternal)
1.941 + GrowableArray<InstanceKlass*>(initial_class_count, true);
1.942 + }
1.943 + _class_list->push(ik);
1.944 +}
1.945 +
1.946 +// returns the instance field map for the given object
1.947 +// (returns field map cached by the InstanceKlass if possible)
1.948 +ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
1.949 + assert(Thread::current()->is_VM_thread(), "must be VMThread");
1.950 + assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
1.951 +
1.952 + Klass* k = obj->klass();
1.953 + InstanceKlass* ik = InstanceKlass::cast(k);
1.954 +
1.955 + // return cached map if possible
1.956 + JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
1.957 + if (cached_map != NULL) {
1.958 + assert(cached_map->field_map() != NULL, "missing field list");
1.959 + return cached_map->field_map();
1.960 + } else {
1.961 + ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
1.962 + cached_map = new JvmtiCachedClassFieldMap(field_map);
1.963 + ik->set_jvmti_cached_class_field_map(cached_map);
1.964 + add_to_class_list(ik);
1.965 + return field_map;
1.966 + }
1.967 +}
1.968 +
1.969 +// remove the fields maps cached from all instanceKlasses
1.970 +void JvmtiCachedClassFieldMap::clear_cache() {
1.971 + assert(Thread::current()->is_VM_thread(), "must be VMThread");
1.972 + if (_class_list != NULL) {
1.973 + for (int i = 0; i < _class_list->length(); i++) {
1.974 + InstanceKlass* ik = _class_list->at(i);
1.975 + JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
1.976 + assert(cached_map != NULL, "should not be NULL");
1.977 + ik->set_jvmti_cached_class_field_map(NULL);
1.978 + delete cached_map; // deletes the encapsulated field map
1.979 + }
1.980 + delete _class_list;
1.981 + _class_list = NULL;
1.982 + }
1.983 +}
1.984 +
1.985 +// returns the number of ClassFieldMap cached by instanceKlasses
1.986 +int JvmtiCachedClassFieldMap::cached_field_map_count() {
1.987 + return (_class_list == NULL) ? 0 : _class_list->length();
1.988 +}
1.989 +
1.990 +// helper function to indicate if an object is filtered by its tag or class tag
1.991 +static inline bool is_filtered_by_heap_filter(jlong obj_tag,
1.992 + jlong klass_tag,
1.993 + int heap_filter) {
1.994 + // apply the heap filter
1.995 + if (obj_tag != 0) {
1.996 + // filter out tagged objects
1.997 + if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
1.998 + } else {
1.999 + // filter out untagged objects
1.1000 + if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
1.1001 + }
1.1002 + if (klass_tag != 0) {
1.1003 + // filter out objects with tagged classes
1.1004 + if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
1.1005 + } else {
1.1006 + // filter out objects with untagged classes.
1.1007 + if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
1.1008 + }
1.1009 + return false;
1.1010 +}
1.1011 +
1.1012 +// helper function to indicate if an object is filtered by a klass filter
1.1013 +static inline bool is_filtered_by_klass_filter(oop obj, KlassHandle klass_filter) {
1.1014 + if (!klass_filter.is_null()) {
1.1015 + if (obj->klass() != klass_filter()) {
1.1016 + return true;
1.1017 + }
1.1018 + }
1.1019 + return false;
1.1020 +}
1.1021 +
1.1022 +// helper function to tell if a field is a primitive field or not
1.1023 +static inline bool is_primitive_field_type(char type) {
1.1024 + return (type != 'L' && type != '[');
1.1025 +}
1.1026 +
1.1027 +// helper function to copy the value from location addr to jvalue.
1.1028 +static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
1.1029 + switch (value_type) {
1.1030 + case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
1.1031 + case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
1.1032 + case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
1.1033 + case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
1.1034 + case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
1.1035 + case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
1.1036 + case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
1.1037 + case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
1.1038 + default: ShouldNotReachHere();
1.1039 + }
1.1040 +}
1.1041 +
1.1042 +// helper function to invoke string primitive value callback
1.1043 +// returns visit control flags
1.1044 +static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
1.1045 + CallbackWrapper* wrapper,
1.1046 + oop str,
1.1047 + void* user_data)
1.1048 +{
1.1049 + assert(str->klass() == SystemDictionary::String_klass(), "not a string");
1.1050 +
1.1051 + // get the string value and length
1.1052 + // (string value may be offset from the base)
1.1053 + int s_len = java_lang_String::length(str);
1.1054 + typeArrayOop s_value = java_lang_String::value(str);
1.1055 + int s_offset = java_lang_String::offset(str);
1.1056 + jchar* value;
1.1057 + if (s_len > 0) {
1.1058 + value = s_value->char_at_addr(s_offset);
1.1059 + } else {
1.1060 + value = (jchar*) s_value->base(T_CHAR);
1.1061 + }
1.1062 +
1.1063 + // invoke the callback
1.1064 + return (*cb)(wrapper->klass_tag(),
1.1065 + wrapper->obj_size(),
1.1066 + wrapper->obj_tag_p(),
1.1067 + value,
1.1068 + (jint)s_len,
1.1069 + user_data);
1.1070 +}
1.1071 +
1.1072 +// helper function to invoke string primitive value callback
1.1073 +// returns visit control flags
1.1074 +static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
1.1075 + CallbackWrapper* wrapper,
1.1076 + oop obj,
1.1077 + void* user_data)
1.1078 +{
1.1079 + assert(obj->is_typeArray(), "not a primitive array");
1.1080 +
1.1081 + // get base address of first element
1.1082 + typeArrayOop array = typeArrayOop(obj);
1.1083 + BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1.1084 + void* elements = array->base(type);
1.1085 +
1.1086 + // jvmtiPrimitiveType is defined so this mapping is always correct
1.1087 + jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
1.1088 +
1.1089 + return (*cb)(wrapper->klass_tag(),
1.1090 + wrapper->obj_size(),
1.1091 + wrapper->obj_tag_p(),
1.1092 + (jint)array->length(),
1.1093 + elem_type,
1.1094 + elements,
1.1095 + user_data);
1.1096 +}
1.1097 +
1.1098 +// helper function to invoke the primitive field callback for all static fields
1.1099 +// of a given class
1.1100 +static jint invoke_primitive_field_callback_for_static_fields
1.1101 + (CallbackWrapper* wrapper,
1.1102 + oop obj,
1.1103 + jvmtiPrimitiveFieldCallback cb,
1.1104 + void* user_data)
1.1105 +{
1.1106 + // for static fields only the index will be set
1.1107 + static jvmtiHeapReferenceInfo reference_info = { 0 };
1.1108 +
1.1109 + assert(obj->klass() == SystemDictionary::Class_klass(), "not a class");
1.1110 + if (java_lang_Class::is_primitive(obj)) {
1.1111 + return 0;
1.1112 + }
1.1113 + Klass* klass = java_lang_Class::as_Klass(obj);
1.1114 +
1.1115 + // ignore classes for object and type arrays
1.1116 + if (!klass->oop_is_instance()) {
1.1117 + return 0;
1.1118 + }
1.1119 +
1.1120 + // ignore classes which aren't linked yet
1.1121 + InstanceKlass* ik = InstanceKlass::cast(klass);
1.1122 + if (!ik->is_linked()) {
1.1123 + return 0;
1.1124 + }
1.1125 +
1.1126 + // get the field map
1.1127 + ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
1.1128 +
1.1129 + // invoke the callback for each static primitive field
1.1130 + for (int i=0; i<field_map->field_count(); i++) {
1.1131 + ClassFieldDescriptor* field = field_map->field_at(i);
1.1132 +
1.1133 + // ignore non-primitive fields
1.1134 + char type = field->field_type();
1.1135 + if (!is_primitive_field_type(type)) {
1.1136 + continue;
1.1137 + }
1.1138 + // one-to-one mapping
1.1139 + jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1.1140 +
1.1141 + // get offset and field value
1.1142 + int offset = field->field_offset();
1.1143 + address addr = (address)klass->java_mirror() + offset;
1.1144 + jvalue value;
1.1145 + copy_to_jvalue(&value, addr, value_type);
1.1146 +
1.1147 + // field index
1.1148 + reference_info.field.index = field->field_index();
1.1149 +
1.1150 + // invoke the callback
1.1151 + jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1.1152 + &reference_info,
1.1153 + wrapper->klass_tag(),
1.1154 + wrapper->obj_tag_p(),
1.1155 + value,
1.1156 + value_type,
1.1157 + user_data);
1.1158 + if (res & JVMTI_VISIT_ABORT) {
1.1159 + delete field_map;
1.1160 + return res;
1.1161 + }
1.1162 + }
1.1163 +
1.1164 + delete field_map;
1.1165 + return 0;
1.1166 +}
1.1167 +
1.1168 +// helper function to invoke the primitive field callback for all instance fields
1.1169 +// of a given object
1.1170 +static jint invoke_primitive_field_callback_for_instance_fields(
1.1171 + CallbackWrapper* wrapper,
1.1172 + oop obj,
1.1173 + jvmtiPrimitiveFieldCallback cb,
1.1174 + void* user_data)
1.1175 +{
1.1176 + // for instance fields only the index will be set
1.1177 + static jvmtiHeapReferenceInfo reference_info = { 0 };
1.1178 +
1.1179 + // get the map of the instance fields
1.1180 + ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
1.1181 +
1.1182 + // invoke the callback for each instance primitive field
1.1183 + for (int i=0; i<fields->field_count(); i++) {
1.1184 + ClassFieldDescriptor* field = fields->field_at(i);
1.1185 +
1.1186 + // ignore non-primitive fields
1.1187 + char type = field->field_type();
1.1188 + if (!is_primitive_field_type(type)) {
1.1189 + continue;
1.1190 + }
1.1191 + // one-to-one mapping
1.1192 + jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1.1193 +
1.1194 + // get offset and field value
1.1195 + int offset = field->field_offset();
1.1196 + address addr = (address)obj + offset;
1.1197 + jvalue value;
1.1198 + copy_to_jvalue(&value, addr, value_type);
1.1199 +
1.1200 + // field index
1.1201 + reference_info.field.index = field->field_index();
1.1202 +
1.1203 + // invoke the callback
1.1204 + jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1.1205 + &reference_info,
1.1206 + wrapper->klass_tag(),
1.1207 + wrapper->obj_tag_p(),
1.1208 + value,
1.1209 + value_type,
1.1210 + user_data);
1.1211 + if (res & JVMTI_VISIT_ABORT) {
1.1212 + return res;
1.1213 + }
1.1214 + }
1.1215 + return 0;
1.1216 +}
1.1217 +
1.1218 +
1.1219 +// VM operation to iterate over all objects in the heap (both reachable
1.1220 +// and unreachable)
1.1221 +class VM_HeapIterateOperation: public VM_Operation {
1.1222 + private:
1.1223 + ObjectClosure* _blk;
1.1224 + public:
1.1225 + VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; }
1.1226 +
1.1227 + VMOp_Type type() const { return VMOp_HeapIterateOperation; }
1.1228 + void doit() {
1.1229 + // allows class files maps to be cached during iteration
1.1230 + ClassFieldMapCacheMark cm;
1.1231 +
1.1232 + // make sure that heap is parsable (fills TLABs with filler objects)
1.1233 + Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1.1234 +
1.1235 + // Verify heap before iteration - if the heap gets corrupted then
1.1236 + // JVMTI's IterateOverHeap will crash.
1.1237 + if (VerifyBeforeIteration) {
1.1238 + Universe::verify();
1.1239 + }
1.1240 +
1.1241 + // do the iteration
1.1242 + // If this operation encounters a bad object when using CMS,
1.1243 + // consider using safe_object_iterate() which avoids perm gen
1.1244 + // objects that may contain bad references.
1.1245 + Universe::heap()->object_iterate(_blk);
1.1246 + }
1.1247 +
1.1248 +};
1.1249 +
1.1250 +
1.1251 +// An ObjectClosure used to support the deprecated IterateOverHeap and
1.1252 +// IterateOverInstancesOfClass functions
1.1253 +class IterateOverHeapObjectClosure: public ObjectClosure {
1.1254 + private:
1.1255 + JvmtiTagMap* _tag_map;
1.1256 + KlassHandle _klass;
1.1257 + jvmtiHeapObjectFilter _object_filter;
1.1258 + jvmtiHeapObjectCallback _heap_object_callback;
1.1259 + const void* _user_data;
1.1260 +
1.1261 + // accessors
1.1262 + JvmtiTagMap* tag_map() const { return _tag_map; }
1.1263 + jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
1.1264 + jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
1.1265 + KlassHandle klass() const { return _klass; }
1.1266 + const void* user_data() const { return _user_data; }
1.1267 +
1.1268 + // indicates if iteration has been aborted
1.1269 + bool _iteration_aborted;
1.1270 + bool is_iteration_aborted() const { return _iteration_aborted; }
1.1271 + void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
1.1272 +
1.1273 + public:
1.1274 + IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
1.1275 + KlassHandle klass,
1.1276 + jvmtiHeapObjectFilter object_filter,
1.1277 + jvmtiHeapObjectCallback heap_object_callback,
1.1278 + const void* user_data) :
1.1279 + _tag_map(tag_map),
1.1280 + _klass(klass),
1.1281 + _object_filter(object_filter),
1.1282 + _heap_object_callback(heap_object_callback),
1.1283 + _user_data(user_data),
1.1284 + _iteration_aborted(false)
1.1285 + {
1.1286 + }
1.1287 +
1.1288 + void do_object(oop o);
1.1289 +};
1.1290 +
1.1291 +// invoked for each object in the heap
1.1292 +void IterateOverHeapObjectClosure::do_object(oop o) {
1.1293 + // check if iteration has been halted
1.1294 + if (is_iteration_aborted()) return;
1.1295 +
1.1296 + // ignore any objects that aren't visible to profiler
1.1297 + if (!ServiceUtil::visible_oop(o)) return;
1.1298 +
1.1299 + // instanceof check when filtering by klass
1.1300 + if (!klass().is_null() && !o->is_a(klass()())) {
1.1301 + return;
1.1302 + }
1.1303 + // prepare for the calllback
1.1304 + CallbackWrapper wrapper(tag_map(), o);
1.1305 +
1.1306 + // if the object is tagged and we're only interested in untagged objects
1.1307 + // then don't invoke the callback. Similiarly, if the object is untagged
1.1308 + // and we're only interested in tagged objects we skip the callback.
1.1309 + if (wrapper.obj_tag() != 0) {
1.1310 + if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
1.1311 + } else {
1.1312 + if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
1.1313 + }
1.1314 +
1.1315 + // invoke the agent's callback
1.1316 + jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
1.1317 + wrapper.obj_size(),
1.1318 + wrapper.obj_tag_p(),
1.1319 + (void*)user_data());
1.1320 + if (control == JVMTI_ITERATION_ABORT) {
1.1321 + set_iteration_aborted(true);
1.1322 + }
1.1323 +}
1.1324 +
1.1325 +// An ObjectClosure used to support the IterateThroughHeap function
1.1326 +class IterateThroughHeapObjectClosure: public ObjectClosure {
1.1327 + private:
1.1328 + JvmtiTagMap* _tag_map;
1.1329 + KlassHandle _klass;
1.1330 + int _heap_filter;
1.1331 + const jvmtiHeapCallbacks* _callbacks;
1.1332 + const void* _user_data;
1.1333 +
1.1334 + // accessor functions
1.1335 + JvmtiTagMap* tag_map() const { return _tag_map; }
1.1336 + int heap_filter() const { return _heap_filter; }
1.1337 + const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1.1338 + KlassHandle klass() const { return _klass; }
1.1339 + const void* user_data() const { return _user_data; }
1.1340 +
1.1341 + // indicates if the iteration has been aborted
1.1342 + bool _iteration_aborted;
1.1343 + bool is_iteration_aborted() const { return _iteration_aborted; }
1.1344 +
1.1345 + // used to check the visit control flags. If the abort flag is set
1.1346 + // then we set the iteration aborted flag so that the iteration completes
1.1347 + // without processing any further objects
1.1348 + bool check_flags_for_abort(jint flags) {
1.1349 + bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1.1350 + if (is_abort) {
1.1351 + _iteration_aborted = true;
1.1352 + }
1.1353 + return is_abort;
1.1354 + }
1.1355 +
1.1356 + public:
1.1357 + IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1.1358 + KlassHandle klass,
1.1359 + int heap_filter,
1.1360 + const jvmtiHeapCallbacks* heap_callbacks,
1.1361 + const void* user_data) :
1.1362 + _tag_map(tag_map),
1.1363 + _klass(klass),
1.1364 + _heap_filter(heap_filter),
1.1365 + _callbacks(heap_callbacks),
1.1366 + _user_data(user_data),
1.1367 + _iteration_aborted(false)
1.1368 + {
1.1369 + }
1.1370 +
1.1371 + void do_object(oop o);
1.1372 +};
1.1373 +
1.1374 +// invoked for each object in the heap
1.1375 +void IterateThroughHeapObjectClosure::do_object(oop obj) {
1.1376 + // check if iteration has been halted
1.1377 + if (is_iteration_aborted()) return;
1.1378 +
1.1379 + // ignore any objects that aren't visible to profiler
1.1380 + if (!ServiceUtil::visible_oop(obj)) return;
1.1381 +
1.1382 + // apply class filter
1.1383 + if (is_filtered_by_klass_filter(obj, klass())) return;
1.1384 +
1.1385 + // prepare for callback
1.1386 + CallbackWrapper wrapper(tag_map(), obj);
1.1387 +
1.1388 + // check if filtered by the heap filter
1.1389 + if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1.1390 + return;
1.1391 + }
1.1392 +
1.1393 + // for arrays we need the length, otherwise -1
1.1394 + bool is_array = obj->is_array();
1.1395 + int len = is_array ? arrayOop(obj)->length() : -1;
1.1396 +
1.1397 + // invoke the object callback (if callback is provided)
1.1398 + if (callbacks()->heap_iteration_callback != NULL) {
1.1399 + jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1.1400 + jint res = (*cb)(wrapper.klass_tag(),
1.1401 + wrapper.obj_size(),
1.1402 + wrapper.obj_tag_p(),
1.1403 + (jint)len,
1.1404 + (void*)user_data());
1.1405 + if (check_flags_for_abort(res)) return;
1.1406 + }
1.1407 +
1.1408 + // for objects and classes we report primitive fields if callback provided
1.1409 + if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
1.1410 + jint res;
1.1411 + jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1.1412 + if (obj->klass() == SystemDictionary::Class_klass()) {
1.1413 + res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1.1414 + obj,
1.1415 + cb,
1.1416 + (void*)user_data());
1.1417 + } else {
1.1418 + res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1.1419 + obj,
1.1420 + cb,
1.1421 + (void*)user_data());
1.1422 + }
1.1423 + if (check_flags_for_abort(res)) return;
1.1424 + }
1.1425 +
1.1426 + // string callback
1.1427 + if (!is_array &&
1.1428 + callbacks()->string_primitive_value_callback != NULL &&
1.1429 + obj->klass() == SystemDictionary::String_klass()) {
1.1430 + jint res = invoke_string_value_callback(
1.1431 + callbacks()->string_primitive_value_callback,
1.1432 + &wrapper,
1.1433 + obj,
1.1434 + (void*)user_data() );
1.1435 + if (check_flags_for_abort(res)) return;
1.1436 + }
1.1437 +
1.1438 + // array callback
1.1439 + if (is_array &&
1.1440 + callbacks()->array_primitive_value_callback != NULL &&
1.1441 + obj->is_typeArray()) {
1.1442 + jint res = invoke_array_primitive_value_callback(
1.1443 + callbacks()->array_primitive_value_callback,
1.1444 + &wrapper,
1.1445 + obj,
1.1446 + (void*)user_data() );
1.1447 + if (check_flags_for_abort(res)) return;
1.1448 + }
1.1449 +};
1.1450 +
1.1451 +
1.1452 +// Deprecated function to iterate over all objects in the heap
1.1453 +void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1.1454 + KlassHandle klass,
1.1455 + jvmtiHeapObjectCallback heap_object_callback,
1.1456 + const void* user_data)
1.1457 +{
1.1458 + MutexLocker ml(Heap_lock);
1.1459 + IterateOverHeapObjectClosure blk(this,
1.1460 + klass,
1.1461 + object_filter,
1.1462 + heap_object_callback,
1.1463 + user_data);
1.1464 + VM_HeapIterateOperation op(&blk);
1.1465 + VMThread::execute(&op);
1.1466 +}
1.1467 +
1.1468 +
1.1469 +// Iterates over all objects in the heap
1.1470 +void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1.1471 + KlassHandle klass,
1.1472 + const jvmtiHeapCallbacks* callbacks,
1.1473 + const void* user_data)
1.1474 +{
1.1475 + MutexLocker ml(Heap_lock);
1.1476 + IterateThroughHeapObjectClosure blk(this,
1.1477 + klass,
1.1478 + heap_filter,
1.1479 + callbacks,
1.1480 + user_data);
1.1481 + VM_HeapIterateOperation op(&blk);
1.1482 + VMThread::execute(&op);
1.1483 +}
1.1484 +
1.1485 +// support class for get_objects_with_tags
1.1486 +
1.1487 +class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
1.1488 + private:
1.1489 + JvmtiEnv* _env;
1.1490 + jlong* _tags;
1.1491 + jint _tag_count;
1.1492 +
1.1493 + GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1.1494 + GrowableArray<uint64_t>* _tag_results; // collected tags
1.1495 +
1.1496 + public:
1.1497 + TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) {
1.1498 + _env = env;
1.1499 + _tags = (jlong*)tags;
1.1500 + _tag_count = tag_count;
1.1501 + _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true);
1.1502 + _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true);
1.1503 + }
1.1504 +
1.1505 + ~TagObjectCollector() {
1.1506 + delete _object_results;
1.1507 + delete _tag_results;
1.1508 + }
1.1509 +
1.1510 + // for each tagged object check if the tag value matches
1.1511 + // - if it matches then we create a JNI local reference to the object
1.1512 + // and record the reference and tag value.
1.1513 + //
1.1514 + void do_entry(JvmtiTagHashmapEntry* entry) {
1.1515 + for (int i=0; i<_tag_count; i++) {
1.1516 + if (_tags[i] == entry->tag()) {
1.1517 + oop o = entry->object();
1.1518 + assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check");
1.1519 + jobject ref = JNIHandles::make_local(JavaThread::current(), o);
1.1520 + _object_results->append(ref);
1.1521 + _tag_results->append((uint64_t)entry->tag());
1.1522 + }
1.1523 + }
1.1524 + }
1.1525 +
1.1526 + // return the results from the collection
1.1527 + //
1.1528 + jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1.1529 + jvmtiError error;
1.1530 + int count = _object_results->length();
1.1531 + assert(count >= 0, "sanity check");
1.1532 +
1.1533 + // if object_result_ptr is not NULL then allocate the result and copy
1.1534 + // in the object references.
1.1535 + if (object_result_ptr != NULL) {
1.1536 + error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1.1537 + if (error != JVMTI_ERROR_NONE) {
1.1538 + return error;
1.1539 + }
1.1540 + for (int i=0; i<count; i++) {
1.1541 + (*object_result_ptr)[i] = _object_results->at(i);
1.1542 + }
1.1543 + }
1.1544 +
1.1545 + // if tag_result_ptr is not NULL then allocate the result and copy
1.1546 + // in the tag values.
1.1547 + if (tag_result_ptr != NULL) {
1.1548 + error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1.1549 + if (error != JVMTI_ERROR_NONE) {
1.1550 + if (object_result_ptr != NULL) {
1.1551 + _env->Deallocate((unsigned char*)object_result_ptr);
1.1552 + }
1.1553 + return error;
1.1554 + }
1.1555 + for (int i=0; i<count; i++) {
1.1556 + (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1.1557 + }
1.1558 + }
1.1559 +
1.1560 + *count_ptr = count;
1.1561 + return JVMTI_ERROR_NONE;
1.1562 + }
1.1563 +};
1.1564 +
1.1565 +// return the list of objects with the specified tags
1.1566 +jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1.1567 + jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1.1568 +
1.1569 + TagObjectCollector collector(env(), tags, count);
1.1570 + {
1.1571 + // iterate over all tagged objects
1.1572 + MutexLocker ml(lock());
1.1573 + entry_iterate(&collector);
1.1574 + }
1.1575 + return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1.1576 +}
1.1577 +
1.1578 +
1.1579 +// ObjectMarker is used to support the marking objects when walking the
1.1580 +// heap.
1.1581 +//
1.1582 +// This implementation uses the existing mark bits in an object for
1.1583 +// marking. Objects that are marked must later have their headers restored.
1.1584 +// As most objects are unlocked and don't have their identity hash computed
1.1585 +// we don't have to save their headers. Instead we save the headers that
1.1586 +// are "interesting". Later when the headers are restored this implementation
1.1587 +// restores all headers to their initial value and then restores the few
1.1588 +// objects that had interesting headers.
1.1589 +//
1.1590 +// Future work: This implementation currently uses growable arrays to save
1.1591 +// the oop and header of interesting objects. As an optimization we could
1.1592 +// use the same technique as the GC and make use of the unused area
1.1593 +// between top() and end().
1.1594 +//
1.1595 +
1.1596 +// An ObjectClosure used to restore the mark bits of an object
1.1597 +class RestoreMarksClosure : public ObjectClosure {
1.1598 + public:
1.1599 + void do_object(oop o) {
1.1600 + if (o != NULL) {
1.1601 + markOop mark = o->mark();
1.1602 + if (mark->is_marked()) {
1.1603 + o->init_mark();
1.1604 + }
1.1605 + }
1.1606 + }
1.1607 +};
1.1608 +
1.1609 +// ObjectMarker provides the mark and visited functions
1.1610 +class ObjectMarker : AllStatic {
1.1611 + private:
1.1612 + // saved headers
1.1613 + static GrowableArray<oop>* _saved_oop_stack;
1.1614 + static GrowableArray<markOop>* _saved_mark_stack;
1.1615 + static bool _needs_reset; // do we need to reset mark bits?
1.1616 +
1.1617 + public:
1.1618 + static void init(); // initialize
1.1619 + static void done(); // clean-up
1.1620 +
1.1621 + static inline void mark(oop o); // mark an object
1.1622 + static inline bool visited(oop o); // check if object has been visited
1.1623 +
1.1624 + static inline bool needs_reset() { return _needs_reset; }
1.1625 + static inline void set_needs_reset(bool v) { _needs_reset = v; }
1.1626 +};
1.1627 +
1.1628 +GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
1.1629 +GrowableArray<markOop>* ObjectMarker::_saved_mark_stack = NULL;
1.1630 +bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
1.1631 +
1.1632 +// initialize ObjectMarker - prepares for object marking
1.1633 +void ObjectMarker::init() {
1.1634 + assert(Thread::current()->is_VM_thread(), "must be VMThread");
1.1635 +
1.1636 + // prepare heap for iteration
1.1637 + Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1.1638 +
1.1639 + // create stacks for interesting headers
1.1640 + _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markOop>(4000, true);
1.1641 + _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
1.1642 +
1.1643 + if (UseBiasedLocking) {
1.1644 + BiasedLocking::preserve_marks();
1.1645 + }
1.1646 +}
1.1647 +
1.1648 +// Object marking is done so restore object headers
1.1649 +void ObjectMarker::done() {
1.1650 + // iterate over all objects and restore the mark bits to
1.1651 + // their initial value
1.1652 + RestoreMarksClosure blk;
1.1653 + if (needs_reset()) {
1.1654 + Universe::heap()->object_iterate(&blk);
1.1655 + } else {
1.1656 + // We don't need to reset mark bits on this call, but reset the
1.1657 + // flag to the default for the next call.
1.1658 + set_needs_reset(true);
1.1659 + }
1.1660 +
1.1661 + // now restore the interesting headers
1.1662 + for (int i = 0; i < _saved_oop_stack->length(); i++) {
1.1663 + oop o = _saved_oop_stack->at(i);
1.1664 + markOop mark = _saved_mark_stack->at(i);
1.1665 + o->set_mark(mark);
1.1666 + }
1.1667 +
1.1668 + if (UseBiasedLocking) {
1.1669 + BiasedLocking::restore_marks();
1.1670 + }
1.1671 +
1.1672 + // free the stacks
1.1673 + delete _saved_oop_stack;
1.1674 + delete _saved_mark_stack;
1.1675 +}
1.1676 +
1.1677 +// mark an object
1.1678 +inline void ObjectMarker::mark(oop o) {
1.1679 + assert(Universe::heap()->is_in(o), "sanity check");
1.1680 + assert(!o->mark()->is_marked(), "should only mark an object once");
1.1681 +
1.1682 + // object's mark word
1.1683 + markOop mark = o->mark();
1.1684 +
1.1685 + if (mark->must_be_preserved(o)) {
1.1686 + _saved_mark_stack->push(mark);
1.1687 + _saved_oop_stack->push(o);
1.1688 + }
1.1689 +
1.1690 + // mark the object
1.1691 + o->set_mark(markOopDesc::prototype()->set_marked());
1.1692 +}
1.1693 +
1.1694 +// return true if object is marked
1.1695 +inline bool ObjectMarker::visited(oop o) {
1.1696 + return o->mark()->is_marked();
1.1697 +}
1.1698 +
1.1699 +// Stack allocated class to help ensure that ObjectMarker is used
1.1700 +// correctly. Constructor initializes ObjectMarker, destructor calls
1.1701 +// ObjectMarker's done() function to restore object headers.
1.1702 +class ObjectMarkerController : public StackObj {
1.1703 + public:
1.1704 + ObjectMarkerController() {
1.1705 + ObjectMarker::init();
1.1706 + }
1.1707 + ~ObjectMarkerController() {
1.1708 + ObjectMarker::done();
1.1709 + }
1.1710 +};
1.1711 +
1.1712 +
1.1713 +// helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1.1714 +// (not performance critical as only used for roots)
1.1715 +static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1.1716 + switch (kind) {
1.1717 + case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1.1718 + case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1.1719 + case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR;
1.1720 + case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1.1721 + case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1.1722 + case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1.1723 + case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1.1724 + default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1.1725 + }
1.1726 +}
1.1727 +
1.1728 +// Base class for all heap walk contexts. The base class maintains a flag
1.1729 +// to indicate if the context is valid or not.
1.1730 +class HeapWalkContext VALUE_OBJ_CLASS_SPEC {
1.1731 + private:
1.1732 + bool _valid;
1.1733 + public:
1.1734 + HeapWalkContext(bool valid) { _valid = valid; }
1.1735 + void invalidate() { _valid = false; }
1.1736 + bool is_valid() const { return _valid; }
1.1737 +};
1.1738 +
1.1739 +// A basic heap walk context for the deprecated heap walking functions.
1.1740 +// The context for a basic heap walk are the callbacks and fields used by
1.1741 +// the referrer caching scheme.
1.1742 +class BasicHeapWalkContext: public HeapWalkContext {
1.1743 + private:
1.1744 + jvmtiHeapRootCallback _heap_root_callback;
1.1745 + jvmtiStackReferenceCallback _stack_ref_callback;
1.1746 + jvmtiObjectReferenceCallback _object_ref_callback;
1.1747 +
1.1748 + // used for caching
1.1749 + oop _last_referrer;
1.1750 + jlong _last_referrer_tag;
1.1751 +
1.1752 + public:
1.1753 + BasicHeapWalkContext() : HeapWalkContext(false) { }
1.1754 +
1.1755 + BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1.1756 + jvmtiStackReferenceCallback stack_ref_callback,
1.1757 + jvmtiObjectReferenceCallback object_ref_callback) :
1.1758 + HeapWalkContext(true),
1.1759 + _heap_root_callback(heap_root_callback),
1.1760 + _stack_ref_callback(stack_ref_callback),
1.1761 + _object_ref_callback(object_ref_callback),
1.1762 + _last_referrer(NULL),
1.1763 + _last_referrer_tag(0) {
1.1764 + }
1.1765 +
1.1766 + // accessors
1.1767 + jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1.1768 + jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1.1769 + jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1.1770 +
1.1771 + oop last_referrer() const { return _last_referrer; }
1.1772 + void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1.1773 + jlong last_referrer_tag() const { return _last_referrer_tag; }
1.1774 + void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1.1775 +};
1.1776 +
1.1777 +// The advanced heap walk context for the FollowReferences functions.
1.1778 +// The context is the callbacks, and the fields used for filtering.
1.1779 +class AdvancedHeapWalkContext: public HeapWalkContext {
1.1780 + private:
1.1781 + jint _heap_filter;
1.1782 + KlassHandle _klass_filter;
1.1783 + const jvmtiHeapCallbacks* _heap_callbacks;
1.1784 +
1.1785 + public:
1.1786 + AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1.1787 +
1.1788 + AdvancedHeapWalkContext(jint heap_filter,
1.1789 + KlassHandle klass_filter,
1.1790 + const jvmtiHeapCallbacks* heap_callbacks) :
1.1791 + HeapWalkContext(true),
1.1792 + _heap_filter(heap_filter),
1.1793 + _klass_filter(klass_filter),
1.1794 + _heap_callbacks(heap_callbacks) {
1.1795 + }
1.1796 +
1.1797 + // accessors
1.1798 + jint heap_filter() const { return _heap_filter; }
1.1799 + KlassHandle klass_filter() const { return _klass_filter; }
1.1800 +
1.1801 + const jvmtiHeapReferenceCallback heap_reference_callback() const {
1.1802 + return _heap_callbacks->heap_reference_callback;
1.1803 + };
1.1804 + const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1.1805 + return _heap_callbacks->primitive_field_callback;
1.1806 + }
1.1807 + const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1.1808 + return _heap_callbacks->array_primitive_value_callback;
1.1809 + }
1.1810 + const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1.1811 + return _heap_callbacks->string_primitive_value_callback;
1.1812 + }
1.1813 +};
1.1814 +
1.1815 +// The CallbackInvoker is a class with static functions that the heap walk can call
1.1816 +// into to invoke callbacks. It works in one of two modes. The "basic" mode is
1.1817 +// used for the deprecated IterateOverReachableObjects functions. The "advanced"
1.1818 +// mode is for the newer FollowReferences function which supports a lot of
1.1819 +// additional callbacks.
1.1820 +class CallbackInvoker : AllStatic {
1.1821 + private:
1.1822 + // heap walk styles
1.1823 + enum { basic, advanced };
1.1824 + static int _heap_walk_type;
1.1825 + static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1.1826 + static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1.1827 +
1.1828 + // context for basic style heap walk
1.1829 + static BasicHeapWalkContext _basic_context;
1.1830 + static BasicHeapWalkContext* basic_context() {
1.1831 + assert(_basic_context.is_valid(), "invalid");
1.1832 + return &_basic_context;
1.1833 + }
1.1834 +
1.1835 + // context for advanced style heap walk
1.1836 + static AdvancedHeapWalkContext _advanced_context;
1.1837 + static AdvancedHeapWalkContext* advanced_context() {
1.1838 + assert(_advanced_context.is_valid(), "invalid");
1.1839 + return &_advanced_context;
1.1840 + }
1.1841 +
1.1842 + // context needed for all heap walks
1.1843 + static JvmtiTagMap* _tag_map;
1.1844 + static const void* _user_data;
1.1845 + static GrowableArray<oop>* _visit_stack;
1.1846 +
1.1847 + // accessors
1.1848 + static JvmtiTagMap* tag_map() { return _tag_map; }
1.1849 + static const void* user_data() { return _user_data; }
1.1850 + static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1.1851 +
1.1852 + // if the object hasn't been visited then push it onto the visit stack
1.1853 + // so that it will be visited later
1.1854 + static inline bool check_for_visit(oop obj) {
1.1855 + if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1.1856 + return true;
1.1857 + }
1.1858 +
1.1859 + // invoke basic style callbacks
1.1860 + static inline bool invoke_basic_heap_root_callback
1.1861 + (jvmtiHeapRootKind root_kind, oop obj);
1.1862 + static inline bool invoke_basic_stack_ref_callback
1.1863 + (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1.1864 + int slot, oop obj);
1.1865 + static inline bool invoke_basic_object_reference_callback
1.1866 + (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1.1867 +
1.1868 + // invoke advanced style callbacks
1.1869 + static inline bool invoke_advanced_heap_root_callback
1.1870 + (jvmtiHeapReferenceKind ref_kind, oop obj);
1.1871 + static inline bool invoke_advanced_stack_ref_callback
1.1872 + (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1.1873 + jmethodID method, jlocation bci, jint slot, oop obj);
1.1874 + static inline bool invoke_advanced_object_reference_callback
1.1875 + (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1.1876 +
1.1877 + // used to report the value of primitive fields
1.1878 + static inline bool report_primitive_field
1.1879 + (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1.1880 +
1.1881 + public:
1.1882 + // initialize for basic mode
1.1883 + static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1.1884 + GrowableArray<oop>* visit_stack,
1.1885 + const void* user_data,
1.1886 + BasicHeapWalkContext context);
1.1887 +
1.1888 + // initialize for advanced mode
1.1889 + static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1.1890 + GrowableArray<oop>* visit_stack,
1.1891 + const void* user_data,
1.1892 + AdvancedHeapWalkContext context);
1.1893 +
1.1894 + // functions to report roots
1.1895 + static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1.1896 + static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1.1897 + jmethodID m, oop o);
1.1898 + static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1.1899 + jmethodID method, jlocation bci, jint slot, oop o);
1.1900 +
1.1901 + // functions to report references
1.1902 + static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1.1903 + static inline bool report_class_reference(oop referrer, oop referree);
1.1904 + static inline bool report_class_loader_reference(oop referrer, oop referree);
1.1905 + static inline bool report_signers_reference(oop referrer, oop referree);
1.1906 + static inline bool report_protection_domain_reference(oop referrer, oop referree);
1.1907 + static inline bool report_superclass_reference(oop referrer, oop referree);
1.1908 + static inline bool report_interface_reference(oop referrer, oop referree);
1.1909 + static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1.1910 + static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1.1911 + static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1.1912 + static inline bool report_primitive_array_values(oop array);
1.1913 + static inline bool report_string_value(oop str);
1.1914 + static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1.1915 + static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1.1916 +};
1.1917 +
1.1918 +// statics
1.1919 +int CallbackInvoker::_heap_walk_type;
1.1920 +BasicHeapWalkContext CallbackInvoker::_basic_context;
1.1921 +AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1.1922 +JvmtiTagMap* CallbackInvoker::_tag_map;
1.1923 +const void* CallbackInvoker::_user_data;
1.1924 +GrowableArray<oop>* CallbackInvoker::_visit_stack;
1.1925 +
1.1926 +// initialize for basic heap walk (IterateOverReachableObjects et al)
1.1927 +void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1.1928 + GrowableArray<oop>* visit_stack,
1.1929 + const void* user_data,
1.1930 + BasicHeapWalkContext context) {
1.1931 + _tag_map = tag_map;
1.1932 + _visit_stack = visit_stack;
1.1933 + _user_data = user_data;
1.1934 + _basic_context = context;
1.1935 + _advanced_context.invalidate(); // will trigger assertion if used
1.1936 + _heap_walk_type = basic;
1.1937 +}
1.1938 +
1.1939 +// initialize for advanced heap walk (FollowReferences)
1.1940 +void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1.1941 + GrowableArray<oop>* visit_stack,
1.1942 + const void* user_data,
1.1943 + AdvancedHeapWalkContext context) {
1.1944 + _tag_map = tag_map;
1.1945 + _visit_stack = visit_stack;
1.1946 + _user_data = user_data;
1.1947 + _advanced_context = context;
1.1948 + _basic_context.invalidate(); // will trigger assertion if used
1.1949 + _heap_walk_type = advanced;
1.1950 +}
1.1951 +
1.1952 +
1.1953 +// invoke basic style heap root callback
1.1954 +inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1.1955 + assert(ServiceUtil::visible_oop(obj), "checking");
1.1956 +
1.1957 + // if we heap roots should be reported
1.1958 + jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1.1959 + if (cb == NULL) {
1.1960 + return check_for_visit(obj);
1.1961 + }
1.1962 +
1.1963 + CallbackWrapper wrapper(tag_map(), obj);
1.1964 + jvmtiIterationControl control = (*cb)(root_kind,
1.1965 + wrapper.klass_tag(),
1.1966 + wrapper.obj_size(),
1.1967 + wrapper.obj_tag_p(),
1.1968 + (void*)user_data());
1.1969 + // push root to visit stack when following references
1.1970 + if (control == JVMTI_ITERATION_CONTINUE &&
1.1971 + basic_context()->object_ref_callback() != NULL) {
1.1972 + visit_stack()->push(obj);
1.1973 + }
1.1974 + return control != JVMTI_ITERATION_ABORT;
1.1975 +}
1.1976 +
1.1977 +// invoke basic style stack ref callback
1.1978 +inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
1.1979 + jlong thread_tag,
1.1980 + jint depth,
1.1981 + jmethodID method,
1.1982 + jint slot,
1.1983 + oop obj) {
1.1984 + assert(ServiceUtil::visible_oop(obj), "checking");
1.1985 +
1.1986 + // if we stack refs should be reported
1.1987 + jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
1.1988 + if (cb == NULL) {
1.1989 + return check_for_visit(obj);
1.1990 + }
1.1991 +
1.1992 + CallbackWrapper wrapper(tag_map(), obj);
1.1993 + jvmtiIterationControl control = (*cb)(root_kind,
1.1994 + wrapper.klass_tag(),
1.1995 + wrapper.obj_size(),
1.1996 + wrapper.obj_tag_p(),
1.1997 + thread_tag,
1.1998 + depth,
1.1999 + method,
1.2000 + slot,
1.2001 + (void*)user_data());
1.2002 + // push root to visit stack when following references
1.2003 + if (control == JVMTI_ITERATION_CONTINUE &&
1.2004 + basic_context()->object_ref_callback() != NULL) {
1.2005 + visit_stack()->push(obj);
1.2006 + }
1.2007 + return control != JVMTI_ITERATION_ABORT;
1.2008 +}
1.2009 +
1.2010 +// invoke basic style object reference callback
1.2011 +inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
1.2012 + oop referrer,
1.2013 + oop referree,
1.2014 + jint index) {
1.2015 +
1.2016 + assert(ServiceUtil::visible_oop(referrer), "checking");
1.2017 + assert(ServiceUtil::visible_oop(referree), "checking");
1.2018 +
1.2019 + BasicHeapWalkContext* context = basic_context();
1.2020 +
1.2021 + // callback requires the referrer's tag. If it's the same referrer
1.2022 + // as the last call then we use the cached value.
1.2023 + jlong referrer_tag;
1.2024 + if (referrer == context->last_referrer()) {
1.2025 + referrer_tag = context->last_referrer_tag();
1.2026 + } else {
1.2027 + referrer_tag = tag_for(tag_map(), referrer);
1.2028 + }
1.2029 +
1.2030 + // do the callback
1.2031 + CallbackWrapper wrapper(tag_map(), referree);
1.2032 + jvmtiObjectReferenceCallback cb = context->object_ref_callback();
1.2033 + jvmtiIterationControl control = (*cb)(ref_kind,
1.2034 + wrapper.klass_tag(),
1.2035 + wrapper.obj_size(),
1.2036 + wrapper.obj_tag_p(),
1.2037 + referrer_tag,
1.2038 + index,
1.2039 + (void*)user_data());
1.2040 +
1.2041 + // record referrer and referrer tag. For self-references record the
1.2042 + // tag value from the callback as this might differ from referrer_tag.
1.2043 + context->set_last_referrer(referrer);
1.2044 + if (referrer == referree) {
1.2045 + context->set_last_referrer_tag(*wrapper.obj_tag_p());
1.2046 + } else {
1.2047 + context->set_last_referrer_tag(referrer_tag);
1.2048 + }
1.2049 +
1.2050 + if (control == JVMTI_ITERATION_CONTINUE) {
1.2051 + return check_for_visit(referree);
1.2052 + } else {
1.2053 + return control != JVMTI_ITERATION_ABORT;
1.2054 + }
1.2055 +}
1.2056 +
1.2057 +// invoke advanced style heap root callback
1.2058 +inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
1.2059 + oop obj) {
1.2060 + assert(ServiceUtil::visible_oop(obj), "checking");
1.2061 +
1.2062 + AdvancedHeapWalkContext* context = advanced_context();
1.2063 +
1.2064 + // check that callback is provided
1.2065 + jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1.2066 + if (cb == NULL) {
1.2067 + return check_for_visit(obj);
1.2068 + }
1.2069 +
1.2070 + // apply class filter
1.2071 + if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1.2072 + return check_for_visit(obj);
1.2073 + }
1.2074 +
1.2075 + // setup the callback wrapper
1.2076 + CallbackWrapper wrapper(tag_map(), obj);
1.2077 +
1.2078 + // apply tag filter
1.2079 + if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1.2080 + wrapper.klass_tag(),
1.2081 + context->heap_filter())) {
1.2082 + return check_for_visit(obj);
1.2083 + }
1.2084 +
1.2085 + // for arrays we need the length, otherwise -1
1.2086 + jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1.2087 +
1.2088 + // invoke the callback
1.2089 + jint res = (*cb)(ref_kind,
1.2090 + NULL, // referrer info
1.2091 + wrapper.klass_tag(),
1.2092 + 0, // referrer_class_tag is 0 for heap root
1.2093 + wrapper.obj_size(),
1.2094 + wrapper.obj_tag_p(),
1.2095 + NULL, // referrer_tag_p
1.2096 + len,
1.2097 + (void*)user_data());
1.2098 + if (res & JVMTI_VISIT_ABORT) {
1.2099 + return false;// referrer class tag
1.2100 + }
1.2101 + if (res & JVMTI_VISIT_OBJECTS) {
1.2102 + check_for_visit(obj);
1.2103 + }
1.2104 + return true;
1.2105 +}
1.2106 +
1.2107 +// report a reference from a thread stack to an object
1.2108 +inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
1.2109 + jlong thread_tag,
1.2110 + jlong tid,
1.2111 + int depth,
1.2112 + jmethodID method,
1.2113 + jlocation bci,
1.2114 + jint slot,
1.2115 + oop obj) {
1.2116 + assert(ServiceUtil::visible_oop(obj), "checking");
1.2117 +
1.2118 + AdvancedHeapWalkContext* context = advanced_context();
1.2119 +
1.2120 + // check that callback is provider
1.2121 + jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1.2122 + if (cb == NULL) {
1.2123 + return check_for_visit(obj);
1.2124 + }
1.2125 +
1.2126 + // apply class filter
1.2127 + if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1.2128 + return check_for_visit(obj);
1.2129 + }
1.2130 +
1.2131 + // setup the callback wrapper
1.2132 + CallbackWrapper wrapper(tag_map(), obj);
1.2133 +
1.2134 + // apply tag filter
1.2135 + if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1.2136 + wrapper.klass_tag(),
1.2137 + context->heap_filter())) {
1.2138 + return check_for_visit(obj);
1.2139 + }
1.2140 +
1.2141 + // setup the referrer info
1.2142 + jvmtiHeapReferenceInfo reference_info;
1.2143 + reference_info.stack_local.thread_tag = thread_tag;
1.2144 + reference_info.stack_local.thread_id = tid;
1.2145 + reference_info.stack_local.depth = depth;
1.2146 + reference_info.stack_local.method = method;
1.2147 + reference_info.stack_local.location = bci;
1.2148 + reference_info.stack_local.slot = slot;
1.2149 +
1.2150 + // for arrays we need the length, otherwise -1
1.2151 + jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1.2152 +
1.2153 + // call into the agent
1.2154 + int res = (*cb)(ref_kind,
1.2155 + &reference_info,
1.2156 + wrapper.klass_tag(),
1.2157 + 0, // referrer_class_tag is 0 for heap root (stack)
1.2158 + wrapper.obj_size(),
1.2159 + wrapper.obj_tag_p(),
1.2160 + NULL, // referrer_tag is 0 for root
1.2161 + len,
1.2162 + (void*)user_data());
1.2163 +
1.2164 + if (res & JVMTI_VISIT_ABORT) {
1.2165 + return false;
1.2166 + }
1.2167 + if (res & JVMTI_VISIT_OBJECTS) {
1.2168 + check_for_visit(obj);
1.2169 + }
1.2170 + return true;
1.2171 +}
1.2172 +
1.2173 +// This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
1.2174 +// only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
1.2175 +#define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
1.2176 + | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
1.2177 + | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
1.2178 + | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
1.2179 + | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
1.2180 + | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
1.2181 +
1.2182 +// invoke the object reference callback to report a reference
1.2183 +inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
1.2184 + oop referrer,
1.2185 + oop obj,
1.2186 + jint index)
1.2187 +{
1.2188 + // field index is only valid field in reference_info
1.2189 + static jvmtiHeapReferenceInfo reference_info = { 0 };
1.2190 +
1.2191 + assert(ServiceUtil::visible_oop(referrer), "checking");
1.2192 + assert(ServiceUtil::visible_oop(obj), "checking");
1.2193 +
1.2194 + AdvancedHeapWalkContext* context = advanced_context();
1.2195 +
1.2196 + // check that callback is provider
1.2197 + jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1.2198 + if (cb == NULL) {
1.2199 + return check_for_visit(obj);
1.2200 + }
1.2201 +
1.2202 + // apply class filter
1.2203 + if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1.2204 + return check_for_visit(obj);
1.2205 + }
1.2206 +
1.2207 + // setup the callback wrapper
1.2208 + TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
1.2209 +
1.2210 + // apply tag filter
1.2211 + if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1.2212 + wrapper.klass_tag(),
1.2213 + context->heap_filter())) {
1.2214 + return check_for_visit(obj);
1.2215 + }
1.2216 +
1.2217 + // field index is only valid field in reference_info
1.2218 + reference_info.field.index = index;
1.2219 +
1.2220 + // for arrays we need the length, otherwise -1
1.2221 + jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1.2222 +
1.2223 + // invoke the callback
1.2224 + int res = (*cb)(ref_kind,
1.2225 + (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
1.2226 + wrapper.klass_tag(),
1.2227 + wrapper.referrer_klass_tag(),
1.2228 + wrapper.obj_size(),
1.2229 + wrapper.obj_tag_p(),
1.2230 + wrapper.referrer_tag_p(),
1.2231 + len,
1.2232 + (void*)user_data());
1.2233 +
1.2234 + if (res & JVMTI_VISIT_ABORT) {
1.2235 + return false;
1.2236 + }
1.2237 + if (res & JVMTI_VISIT_OBJECTS) {
1.2238 + check_for_visit(obj);
1.2239 + }
1.2240 + return true;
1.2241 +}
1.2242 +
1.2243 +// report a "simple root"
1.2244 +inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
1.2245 + assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
1.2246 + kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
1.2247 + assert(ServiceUtil::visible_oop(obj), "checking");
1.2248 +
1.2249 + if (is_basic_heap_walk()) {
1.2250 + // map to old style root kind
1.2251 + jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
1.2252 + return invoke_basic_heap_root_callback(root_kind, obj);
1.2253 + } else {
1.2254 + assert(is_advanced_heap_walk(), "wrong heap walk type");
1.2255 + return invoke_advanced_heap_root_callback(kind, obj);
1.2256 + }
1.2257 +}
1.2258 +
1.2259 +
1.2260 +// invoke the primitive array values
1.2261 +inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
1.2262 + assert(obj->is_typeArray(), "not a primitive array");
1.2263 +
1.2264 + AdvancedHeapWalkContext* context = advanced_context();
1.2265 + assert(context->array_primitive_value_callback() != NULL, "no callback");
1.2266 +
1.2267 + // apply class filter
1.2268 + if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1.2269 + return true;
1.2270 + }
1.2271 +
1.2272 + CallbackWrapper wrapper(tag_map(), obj);
1.2273 +
1.2274 + // apply tag filter
1.2275 + if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1.2276 + wrapper.klass_tag(),
1.2277 + context->heap_filter())) {
1.2278 + return true;
1.2279 + }
1.2280 +
1.2281 + // invoke the callback
1.2282 + int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
1.2283 + &wrapper,
1.2284 + obj,
1.2285 + (void*)user_data());
1.2286 + return (!(res & JVMTI_VISIT_ABORT));
1.2287 +}
1.2288 +
1.2289 +// invoke the string value callback
1.2290 +inline bool CallbackInvoker::report_string_value(oop str) {
1.2291 + assert(str->klass() == SystemDictionary::String_klass(), "not a string");
1.2292 +
1.2293 + AdvancedHeapWalkContext* context = advanced_context();
1.2294 + assert(context->string_primitive_value_callback() != NULL, "no callback");
1.2295 +
1.2296 + // apply class filter
1.2297 + if (is_filtered_by_klass_filter(str, context->klass_filter())) {
1.2298 + return true;
1.2299 + }
1.2300 +
1.2301 + CallbackWrapper wrapper(tag_map(), str);
1.2302 +
1.2303 + // apply tag filter
1.2304 + if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1.2305 + wrapper.klass_tag(),
1.2306 + context->heap_filter())) {
1.2307 + return true;
1.2308 + }
1.2309 +
1.2310 + // invoke the callback
1.2311 + int res = invoke_string_value_callback(context->string_primitive_value_callback(),
1.2312 + &wrapper,
1.2313 + str,
1.2314 + (void*)user_data());
1.2315 + return (!(res & JVMTI_VISIT_ABORT));
1.2316 +}
1.2317 +
1.2318 +// invoke the primitive field callback
1.2319 +inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
1.2320 + oop obj,
1.2321 + jint index,
1.2322 + address addr,
1.2323 + char type)
1.2324 +{
1.2325 + // for primitive fields only the index will be set
1.2326 + static jvmtiHeapReferenceInfo reference_info = { 0 };
1.2327 +
1.2328 + AdvancedHeapWalkContext* context = advanced_context();
1.2329 + assert(context->primitive_field_callback() != NULL, "no callback");
1.2330 +
1.2331 + // apply class filter
1.2332 + if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1.2333 + return true;
1.2334 + }
1.2335 +
1.2336 + CallbackWrapper wrapper(tag_map(), obj);
1.2337 +
1.2338 + // apply tag filter
1.2339 + if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1.2340 + wrapper.klass_tag(),
1.2341 + context->heap_filter())) {
1.2342 + return true;
1.2343 + }
1.2344 +
1.2345 + // the field index in the referrer
1.2346 + reference_info.field.index = index;
1.2347 +
1.2348 + // map the type
1.2349 + jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1.2350 +
1.2351 + // setup the jvalue
1.2352 + jvalue value;
1.2353 + copy_to_jvalue(&value, addr, value_type);
1.2354 +
1.2355 + jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
1.2356 + int res = (*cb)(ref_kind,
1.2357 + &reference_info,
1.2358 + wrapper.klass_tag(),
1.2359 + wrapper.obj_tag_p(),
1.2360 + value,
1.2361 + value_type,
1.2362 + (void*)user_data());
1.2363 + return (!(res & JVMTI_VISIT_ABORT));
1.2364 +}
1.2365 +
1.2366 +
1.2367 +// instance field
1.2368 +inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
1.2369 + jint index,
1.2370 + address value,
1.2371 + char type) {
1.2372 + return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
1.2373 + obj,
1.2374 + index,
1.2375 + value,
1.2376 + type);
1.2377 +}
1.2378 +
1.2379 +// static field
1.2380 +inline bool CallbackInvoker::report_primitive_static_field(oop obj,
1.2381 + jint index,
1.2382 + address value,
1.2383 + char type) {
1.2384 + return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1.2385 + obj,
1.2386 + index,
1.2387 + value,
1.2388 + type);
1.2389 +}
1.2390 +
1.2391 +// report a JNI local (root object) to the profiler
1.2392 +inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
1.2393 + if (is_basic_heap_walk()) {
1.2394 + return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
1.2395 + thread_tag,
1.2396 + depth,
1.2397 + m,
1.2398 + -1,
1.2399 + obj);
1.2400 + } else {
1.2401 + return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
1.2402 + thread_tag, tid,
1.2403 + depth,
1.2404 + m,
1.2405 + (jlocation)-1,
1.2406 + -1,
1.2407 + obj);
1.2408 + }
1.2409 +}
1.2410 +
1.2411 +
1.2412 +// report a local (stack reference, root object)
1.2413 +inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
1.2414 + jlong tid,
1.2415 + jint depth,
1.2416 + jmethodID method,
1.2417 + jlocation bci,
1.2418 + jint slot,
1.2419 + oop obj) {
1.2420 + if (is_basic_heap_walk()) {
1.2421 + return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
1.2422 + thread_tag,
1.2423 + depth,
1.2424 + method,
1.2425 + slot,
1.2426 + obj);
1.2427 + } else {
1.2428 + return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
1.2429 + thread_tag,
1.2430 + tid,
1.2431 + depth,
1.2432 + method,
1.2433 + bci,
1.2434 + slot,
1.2435 + obj);
1.2436 + }
1.2437 +}
1.2438 +
1.2439 +// report an object referencing a class.
1.2440 +inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
1.2441 + if (is_basic_heap_walk()) {
1.2442 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
1.2443 + } else {
1.2444 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
1.2445 + }
1.2446 +}
1.2447 +
1.2448 +// report a class referencing its class loader.
1.2449 +inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
1.2450 + if (is_basic_heap_walk()) {
1.2451 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
1.2452 + } else {
1.2453 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
1.2454 + }
1.2455 +}
1.2456 +
1.2457 +// report a class referencing its signers.
1.2458 +inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
1.2459 + if (is_basic_heap_walk()) {
1.2460 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
1.2461 + } else {
1.2462 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
1.2463 + }
1.2464 +}
1.2465 +
1.2466 +// report a class referencing its protection domain..
1.2467 +inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
1.2468 + if (is_basic_heap_walk()) {
1.2469 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
1.2470 + } else {
1.2471 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
1.2472 + }
1.2473 +}
1.2474 +
1.2475 +// report a class referencing its superclass.
1.2476 +inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
1.2477 + if (is_basic_heap_walk()) {
1.2478 + // Send this to be consistent with past implementation
1.2479 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
1.2480 + } else {
1.2481 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
1.2482 + }
1.2483 +}
1.2484 +
1.2485 +// report a class referencing one of its interfaces.
1.2486 +inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
1.2487 + if (is_basic_heap_walk()) {
1.2488 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
1.2489 + } else {
1.2490 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
1.2491 + }
1.2492 +}
1.2493 +
1.2494 +// report a class referencing one of its static fields.
1.2495 +inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
1.2496 + if (is_basic_heap_walk()) {
1.2497 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
1.2498 + } else {
1.2499 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
1.2500 + }
1.2501 +}
1.2502 +
1.2503 +// report an array referencing an element object
1.2504 +inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
1.2505 + if (is_basic_heap_walk()) {
1.2506 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
1.2507 + } else {
1.2508 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
1.2509 + }
1.2510 +}
1.2511 +
1.2512 +// report an object referencing an instance field object
1.2513 +inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
1.2514 + if (is_basic_heap_walk()) {
1.2515 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
1.2516 + } else {
1.2517 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
1.2518 + }
1.2519 +}
1.2520 +
1.2521 +// report an array referencing an element object
1.2522 +inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
1.2523 + if (is_basic_heap_walk()) {
1.2524 + return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
1.2525 + } else {
1.2526 + return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
1.2527 + }
1.2528 +}
1.2529 +
1.2530 +// A supporting closure used to process simple roots
1.2531 +class SimpleRootsClosure : public OopClosure {
1.2532 + private:
1.2533 + jvmtiHeapReferenceKind _kind;
1.2534 + bool _continue;
1.2535 +
1.2536 + jvmtiHeapReferenceKind root_kind() { return _kind; }
1.2537 +
1.2538 + public:
1.2539 + void set_kind(jvmtiHeapReferenceKind kind) {
1.2540 + _kind = kind;
1.2541 + _continue = true;
1.2542 + }
1.2543 +
1.2544 + inline bool stopped() {
1.2545 + return !_continue;
1.2546 + }
1.2547 +
1.2548 + void do_oop(oop* obj_p) {
1.2549 + // iteration has terminated
1.2550 + if (stopped()) {
1.2551 + return;
1.2552 + }
1.2553 +
1.2554 + // ignore null or deleted handles
1.2555 + oop o = *obj_p;
1.2556 + if (o == NULL || o == JNIHandles::deleted_handle()) {
1.2557 + return;
1.2558 + }
1.2559 +
1.2560 + assert(Universe::heap()->is_in_reserved(o), "should be impossible");
1.2561 +
1.2562 + jvmtiHeapReferenceKind kind = root_kind();
1.2563 + if (kind == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) {
1.2564 + // SystemDictionary::always_strong_oops_do reports the application
1.2565 + // class loader as a root. We want this root to be reported as
1.2566 + // a root kind of "OTHER" rather than "SYSTEM_CLASS".
1.2567 + if (!o->is_instanceMirror()) {
1.2568 + kind = JVMTI_HEAP_REFERENCE_OTHER;
1.2569 + }
1.2570 + }
1.2571 +
1.2572 + // some objects are ignored - in the case of simple
1.2573 + // roots it's mostly Symbol*s that we are skipping
1.2574 + // here.
1.2575 + if (!ServiceUtil::visible_oop(o)) {
1.2576 + return;
1.2577 + }
1.2578 +
1.2579 + // invoke the callback
1.2580 + _continue = CallbackInvoker::report_simple_root(kind, o);
1.2581 +
1.2582 + }
1.2583 + virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1.2584 +};
1.2585 +
1.2586 +// A supporting closure used to process JNI locals
1.2587 +class JNILocalRootsClosure : public OopClosure {
1.2588 + private:
1.2589 + jlong _thread_tag;
1.2590 + jlong _tid;
1.2591 + jint _depth;
1.2592 + jmethodID _method;
1.2593 + bool _continue;
1.2594 + public:
1.2595 + void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
1.2596 + _thread_tag = thread_tag;
1.2597 + _tid = tid;
1.2598 + _depth = depth;
1.2599 + _method = method;
1.2600 + _continue = true;
1.2601 + }
1.2602 +
1.2603 + inline bool stopped() {
1.2604 + return !_continue;
1.2605 + }
1.2606 +
1.2607 + void do_oop(oop* obj_p) {
1.2608 + // iteration has terminated
1.2609 + if (stopped()) {
1.2610 + return;
1.2611 + }
1.2612 +
1.2613 + // ignore null or deleted handles
1.2614 + oop o = *obj_p;
1.2615 + if (o == NULL || o == JNIHandles::deleted_handle()) {
1.2616 + return;
1.2617 + }
1.2618 +
1.2619 + if (!ServiceUtil::visible_oop(o)) {
1.2620 + return;
1.2621 + }
1.2622 +
1.2623 + // invoke the callback
1.2624 + _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
1.2625 + }
1.2626 + virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1.2627 +};
1.2628 +
1.2629 +
1.2630 +// A VM operation to iterate over objects that are reachable from
1.2631 +// a set of roots or an initial object.
1.2632 +//
1.2633 +// For VM_HeapWalkOperation the set of roots used is :-
1.2634 +//
1.2635 +// - All JNI global references
1.2636 +// - All inflated monitors
1.2637 +// - All classes loaded by the boot class loader (or all classes
1.2638 +// in the event that class unloading is disabled)
1.2639 +// - All java threads
1.2640 +// - For each java thread then all locals and JNI local references
1.2641 +// on the thread's execution stack
1.2642 +// - All visible/explainable objects from Universes::oops_do
1.2643 +//
1.2644 +class VM_HeapWalkOperation: public VM_Operation {
1.2645 + private:
1.2646 + enum {
1.2647 + initial_visit_stack_size = 4000
1.2648 + };
1.2649 +
1.2650 + bool _is_advanced_heap_walk; // indicates FollowReferences
1.2651 + JvmtiTagMap* _tag_map;
1.2652 + Handle _initial_object;
1.2653 + GrowableArray<oop>* _visit_stack; // the visit stack
1.2654 +
1.2655 + bool _collecting_heap_roots; // are we collecting roots
1.2656 + bool _following_object_refs; // are we following object references
1.2657 +
1.2658 + bool _reporting_primitive_fields; // optional reporting
1.2659 + bool _reporting_primitive_array_values;
1.2660 + bool _reporting_string_values;
1.2661 +
1.2662 + GrowableArray<oop>* create_visit_stack() {
1.2663 + return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true);
1.2664 + }
1.2665 +
1.2666 + // accessors
1.2667 + bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
1.2668 + JvmtiTagMap* tag_map() const { return _tag_map; }
1.2669 + Handle initial_object() const { return _initial_object; }
1.2670 +
1.2671 + bool is_following_references() const { return _following_object_refs; }
1.2672 +
1.2673 + bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
1.2674 + bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
1.2675 + bool is_reporting_string_values() const { return _reporting_string_values; }
1.2676 +
1.2677 + GrowableArray<oop>* visit_stack() const { return _visit_stack; }
1.2678 +
1.2679 + // iterate over the various object types
1.2680 + inline bool iterate_over_array(oop o);
1.2681 + inline bool iterate_over_type_array(oop o);
1.2682 + inline bool iterate_over_class(oop o);
1.2683 + inline bool iterate_over_object(oop o);
1.2684 +
1.2685 + // root collection
1.2686 + inline bool collect_simple_roots();
1.2687 + inline bool collect_stack_roots();
1.2688 + inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
1.2689 +
1.2690 + // visit an object
1.2691 + inline bool visit(oop o);
1.2692 +
1.2693 + public:
1.2694 + VM_HeapWalkOperation(JvmtiTagMap* tag_map,
1.2695 + Handle initial_object,
1.2696 + BasicHeapWalkContext callbacks,
1.2697 + const void* user_data);
1.2698 +
1.2699 + VM_HeapWalkOperation(JvmtiTagMap* tag_map,
1.2700 + Handle initial_object,
1.2701 + AdvancedHeapWalkContext callbacks,
1.2702 + const void* user_data);
1.2703 +
1.2704 + ~VM_HeapWalkOperation();
1.2705 +
1.2706 + VMOp_Type type() const { return VMOp_HeapWalkOperation; }
1.2707 + void doit();
1.2708 +};
1.2709 +
1.2710 +
1.2711 +VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
1.2712 + Handle initial_object,
1.2713 + BasicHeapWalkContext callbacks,
1.2714 + const void* user_data) {
1.2715 + _is_advanced_heap_walk = false;
1.2716 + _tag_map = tag_map;
1.2717 + _initial_object = initial_object;
1.2718 + _following_object_refs = (callbacks.object_ref_callback() != NULL);
1.2719 + _reporting_primitive_fields = false;
1.2720 + _reporting_primitive_array_values = false;
1.2721 + _reporting_string_values = false;
1.2722 + _visit_stack = create_visit_stack();
1.2723 +
1.2724 +
1.2725 + CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
1.2726 +}
1.2727 +
1.2728 +VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
1.2729 + Handle initial_object,
1.2730 + AdvancedHeapWalkContext callbacks,
1.2731 + const void* user_data) {
1.2732 + _is_advanced_heap_walk = true;
1.2733 + _tag_map = tag_map;
1.2734 + _initial_object = initial_object;
1.2735 + _following_object_refs = true;
1.2736 + _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
1.2737 + _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
1.2738 + _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
1.2739 + _visit_stack = create_visit_stack();
1.2740 +
1.2741 + CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
1.2742 +}
1.2743 +
1.2744 +VM_HeapWalkOperation::~VM_HeapWalkOperation() {
1.2745 + if (_following_object_refs) {
1.2746 + assert(_visit_stack != NULL, "checking");
1.2747 + delete _visit_stack;
1.2748 + _visit_stack = NULL;
1.2749 + }
1.2750 +}
1.2751 +
1.2752 +// an array references its class and has a reference to
1.2753 +// each element in the array
1.2754 +inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
1.2755 + objArrayOop array = objArrayOop(o);
1.2756 +
1.2757 + // array reference to its class
1.2758 + oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
1.2759 + if (!CallbackInvoker::report_class_reference(o, mirror)) {
1.2760 + return false;
1.2761 + }
1.2762 +
1.2763 + // iterate over the array and report each reference to a
1.2764 + // non-null element
1.2765 + for (int index=0; index<array->length(); index++) {
1.2766 + oop elem = array->obj_at(index);
1.2767 + if (elem == NULL) {
1.2768 + continue;
1.2769 + }
1.2770 +
1.2771 + // report the array reference o[index] = elem
1.2772 + if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
1.2773 + return false;
1.2774 + }
1.2775 + }
1.2776 + return true;
1.2777 +}
1.2778 +
1.2779 +// a type array references its class
1.2780 +inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
1.2781 + Klass* k = o->klass();
1.2782 + oop mirror = k->java_mirror();
1.2783 + if (!CallbackInvoker::report_class_reference(o, mirror)) {
1.2784 + return false;
1.2785 + }
1.2786 +
1.2787 + // report the array contents if required
1.2788 + if (is_reporting_primitive_array_values()) {
1.2789 + if (!CallbackInvoker::report_primitive_array_values(o)) {
1.2790 + return false;
1.2791 + }
1.2792 + }
1.2793 + return true;
1.2794 +}
1.2795 +
1.2796 +// verify that a static oop field is in range
1.2797 +static inline bool verify_static_oop(InstanceKlass* ik,
1.2798 + oop mirror, int offset) {
1.2799 + address obj_p = (address)mirror + offset;
1.2800 + address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
1.2801 + address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
1.2802 + assert(end >= start, "sanity check");
1.2803 +
1.2804 + if (obj_p >= start && obj_p < end) {
1.2805 + return true;
1.2806 + } else {
1.2807 + return false;
1.2808 + }
1.2809 +}
1.2810 +
1.2811 +// a class references its super class, interfaces, class loader, ...
1.2812 +// and finally its static fields
1.2813 +inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
1.2814 + int i;
1.2815 + Klass* klass = java_lang_Class::as_Klass(java_class);
1.2816 +
1.2817 + if (klass->oop_is_instance()) {
1.2818 + InstanceKlass* ik = InstanceKlass::cast(klass);
1.2819 +
1.2820 + // ignore the class if it's has been initialized yet
1.2821 + if (!ik->is_linked()) {
1.2822 + return true;
1.2823 + }
1.2824 +
1.2825 + // get the java mirror
1.2826 + oop mirror = klass->java_mirror();
1.2827 +
1.2828 + // super (only if something more interesting than java.lang.Object)
1.2829 + Klass* java_super = ik->java_super();
1.2830 + if (java_super != NULL && java_super != SystemDictionary::Object_klass()) {
1.2831 + oop super = java_super->java_mirror();
1.2832 + if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
1.2833 + return false;
1.2834 + }
1.2835 + }
1.2836 +
1.2837 + // class loader
1.2838 + oop cl = ik->class_loader();
1.2839 + if (cl != NULL) {
1.2840 + if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
1.2841 + return false;
1.2842 + }
1.2843 + }
1.2844 +
1.2845 + // protection domain
1.2846 + oop pd = ik->protection_domain();
1.2847 + if (pd != NULL) {
1.2848 + if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
1.2849 + return false;
1.2850 + }
1.2851 + }
1.2852 +
1.2853 + // signers
1.2854 + oop signers = ik->signers();
1.2855 + if (signers != NULL) {
1.2856 + if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
1.2857 + return false;
1.2858 + }
1.2859 + }
1.2860 +
1.2861 + // references from the constant pool
1.2862 + {
1.2863 + ConstantPool* pool = ik->constants();
1.2864 + for (int i = 1; i < pool->length(); i++) {
1.2865 + constantTag tag = pool->tag_at(i).value();
1.2866 + if (tag.is_string() || tag.is_klass()) {
1.2867 + oop entry;
1.2868 + if (tag.is_string()) {
1.2869 + entry = pool->resolved_string_at(i);
1.2870 + // If the entry is non-null it is resolved.
1.2871 + if (entry == NULL) continue;
1.2872 + } else {
1.2873 + entry = pool->resolved_klass_at(i)->java_mirror();
1.2874 + }
1.2875 + if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
1.2876 + return false;
1.2877 + }
1.2878 + }
1.2879 + }
1.2880 + }
1.2881 +
1.2882 + // interfaces
1.2883 + // (These will already have been reported as references from the constant pool
1.2884 + // but are specified by IterateOverReachableObjects and must be reported).
1.2885 + Array<Klass*>* interfaces = ik->local_interfaces();
1.2886 + for (i = 0; i < interfaces->length(); i++) {
1.2887 + oop interf = ((Klass*)interfaces->at(i))->java_mirror();
1.2888 + if (interf == NULL) {
1.2889 + continue;
1.2890 + }
1.2891 + if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
1.2892 + return false;
1.2893 + }
1.2894 + }
1.2895 +
1.2896 + // iterate over the static fields
1.2897 +
1.2898 + ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
1.2899 + for (i=0; i<field_map->field_count(); i++) {
1.2900 + ClassFieldDescriptor* field = field_map->field_at(i);
1.2901 + char type = field->field_type();
1.2902 + if (!is_primitive_field_type(type)) {
1.2903 + oop fld_o = mirror->obj_field(field->field_offset());
1.2904 + assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
1.2905 + if (fld_o != NULL) {
1.2906 + int slot = field->field_index();
1.2907 + if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
1.2908 + delete field_map;
1.2909 + return false;
1.2910 + }
1.2911 + }
1.2912 + } else {
1.2913 + if (is_reporting_primitive_fields()) {
1.2914 + address addr = (address)mirror + field->field_offset();
1.2915 + int slot = field->field_index();
1.2916 + if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
1.2917 + delete field_map;
1.2918 + return false;
1.2919 + }
1.2920 + }
1.2921 + }
1.2922 + }
1.2923 + delete field_map;
1.2924 +
1.2925 + return true;
1.2926 + }
1.2927 +
1.2928 + return true;
1.2929 +}
1.2930 +
1.2931 +// an object references a class and its instance fields
1.2932 +// (static fields are ignored here as we report these as
1.2933 +// references from the class).
1.2934 +inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
1.2935 + // reference to the class
1.2936 + if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
1.2937 + return false;
1.2938 + }
1.2939 +
1.2940 + // iterate over instance fields
1.2941 + ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
1.2942 + for (int i=0; i<field_map->field_count(); i++) {
1.2943 + ClassFieldDescriptor* field = field_map->field_at(i);
1.2944 + char type = field->field_type();
1.2945 + if (!is_primitive_field_type(type)) {
1.2946 + oop fld_o = o->obj_field(field->field_offset());
1.2947 + // ignore any objects that aren't visible to profiler
1.2948 + if (fld_o != NULL && ServiceUtil::visible_oop(fld_o)) {
1.2949 + assert(Universe::heap()->is_in_reserved(fld_o), "unsafe code should not "
1.2950 + "have references to Klass* anymore");
1.2951 + int slot = field->field_index();
1.2952 + if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
1.2953 + return false;
1.2954 + }
1.2955 + }
1.2956 + } else {
1.2957 + if (is_reporting_primitive_fields()) {
1.2958 + // primitive instance field
1.2959 + address addr = (address)o + field->field_offset();
1.2960 + int slot = field->field_index();
1.2961 + if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
1.2962 + return false;
1.2963 + }
1.2964 + }
1.2965 + }
1.2966 + }
1.2967 +
1.2968 + // if the object is a java.lang.String
1.2969 + if (is_reporting_string_values() &&
1.2970 + o->klass() == SystemDictionary::String_klass()) {
1.2971 + if (!CallbackInvoker::report_string_value(o)) {
1.2972 + return false;
1.2973 + }
1.2974 + }
1.2975 + return true;
1.2976 +}
1.2977 +
1.2978 +
1.2979 +// Collects all simple (non-stack) roots except for threads;
1.2980 +// threads are handled in collect_stack_roots() as an optimization.
1.2981 +// if there's a heap root callback provided then the callback is
1.2982 +// invoked for each simple root.
1.2983 +// if an object reference callback is provided then all simple
1.2984 +// roots are pushed onto the marking stack so that they can be
1.2985 +// processed later
1.2986 +//
1.2987 +inline bool VM_HeapWalkOperation::collect_simple_roots() {
1.2988 + SimpleRootsClosure blk;
1.2989 +
1.2990 + // JNI globals
1.2991 + blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
1.2992 + JNIHandles::oops_do(&blk);
1.2993 + if (blk.stopped()) {
1.2994 + return false;
1.2995 + }
1.2996 +
1.2997 + // Preloaded classes and loader from the system dictionary
1.2998 + blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
1.2999 + SystemDictionary::always_strong_oops_do(&blk);
1.3000 + KlassToOopClosure klass_blk(&blk);
1.3001 + ClassLoaderDataGraph::always_strong_oops_do(&blk, &klass_blk, false);
1.3002 + if (blk.stopped()) {
1.3003 + return false;
1.3004 + }
1.3005 +
1.3006 + // Inflated monitors
1.3007 + blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR);
1.3008 + ObjectSynchronizer::oops_do(&blk);
1.3009 + if (blk.stopped()) {
1.3010 + return false;
1.3011 + }
1.3012 +
1.3013 + // threads are now handled in collect_stack_roots()
1.3014 +
1.3015 + // Other kinds of roots maintained by HotSpot
1.3016 + // Many of these won't be visible but others (such as instances of important
1.3017 + // exceptions) will be visible.
1.3018 + blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
1.3019 + Universe::oops_do(&blk);
1.3020 +
1.3021 + // If there are any non-perm roots in the code cache, visit them.
1.3022 + blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
1.3023 + CodeBlobToOopClosure look_in_blobs(&blk, false);
1.3024 + CodeCache::scavenge_root_nmethods_do(&look_in_blobs);
1.3025 +
1.3026 + return true;
1.3027 +}
1.3028 +
1.3029 +// Walk the stack of a given thread and find all references (locals
1.3030 +// and JNI calls) and report these as stack references
1.3031 +inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
1.3032 + JNILocalRootsClosure* blk)
1.3033 +{
1.3034 + oop threadObj = java_thread->threadObj();
1.3035 + assert(threadObj != NULL, "sanity check");
1.3036 +
1.3037 + // only need to get the thread's tag once per thread
1.3038 + jlong thread_tag = tag_for(_tag_map, threadObj);
1.3039 +
1.3040 + // also need the thread id
1.3041 + jlong tid = java_lang_Thread::thread_id(threadObj);
1.3042 +
1.3043 +
1.3044 + if (java_thread->has_last_Java_frame()) {
1.3045 +
1.3046 + // vframes are resource allocated
1.3047 + Thread* current_thread = Thread::current();
1.3048 + ResourceMark rm(current_thread);
1.3049 + HandleMark hm(current_thread);
1.3050 +
1.3051 + RegisterMap reg_map(java_thread);
1.3052 + frame f = java_thread->last_frame();
1.3053 + vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
1.3054 +
1.3055 + bool is_top_frame = true;
1.3056 + int depth = 0;
1.3057 + frame* last_entry_frame = NULL;
1.3058 +
1.3059 + while (vf != NULL) {
1.3060 + if (vf->is_java_frame()) {
1.3061 +
1.3062 + // java frame (interpreted, compiled, ...)
1.3063 + javaVFrame *jvf = javaVFrame::cast(vf);
1.3064 +
1.3065 + // the jmethodID
1.3066 + jmethodID method = jvf->method()->jmethod_id();
1.3067 +
1.3068 + if (!(jvf->method()->is_native())) {
1.3069 + jlocation bci = (jlocation)jvf->bci();
1.3070 + StackValueCollection* locals = jvf->locals();
1.3071 + for (int slot=0; slot<locals->size(); slot++) {
1.3072 + if (locals->at(slot)->type() == T_OBJECT) {
1.3073 + oop o = locals->obj_at(slot)();
1.3074 + if (o == NULL) {
1.3075 + continue;
1.3076 + }
1.3077 +
1.3078 + // stack reference
1.3079 + if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
1.3080 + bci, slot, o)) {
1.3081 + return false;
1.3082 + }
1.3083 + }
1.3084 + }
1.3085 + } else {
1.3086 + blk->set_context(thread_tag, tid, depth, method);
1.3087 + if (is_top_frame) {
1.3088 + // JNI locals for the top frame.
1.3089 + java_thread->active_handles()->oops_do(blk);
1.3090 + } else {
1.3091 + if (last_entry_frame != NULL) {
1.3092 + // JNI locals for the entry frame
1.3093 + assert(last_entry_frame->is_entry_frame(), "checking");
1.3094 + last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
1.3095 + }
1.3096 + }
1.3097 + }
1.3098 + last_entry_frame = NULL;
1.3099 + depth++;
1.3100 + } else {
1.3101 + // externalVFrame - for an entry frame then we report the JNI locals
1.3102 + // when we find the corresponding javaVFrame
1.3103 + frame* fr = vf->frame_pointer();
1.3104 + assert(fr != NULL, "sanity check");
1.3105 + if (fr->is_entry_frame()) {
1.3106 + last_entry_frame = fr;
1.3107 + }
1.3108 + }
1.3109 +
1.3110 + vf = vf->sender();
1.3111 + is_top_frame = false;
1.3112 + }
1.3113 + } else {
1.3114 + // no last java frame but there may be JNI locals
1.3115 + blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
1.3116 + java_thread->active_handles()->oops_do(blk);
1.3117 + }
1.3118 + return true;
1.3119 +}
1.3120 +
1.3121 +
1.3122 +// Collects the simple roots for all threads and collects all
1.3123 +// stack roots - for each thread it walks the execution
1.3124 +// stack to find all references and local JNI refs.
1.3125 +inline bool VM_HeapWalkOperation::collect_stack_roots() {
1.3126 + JNILocalRootsClosure blk;
1.3127 + for (JavaThread* thread = Threads::first(); thread != NULL ; thread = thread->next()) {
1.3128 + oop threadObj = thread->threadObj();
1.3129 + if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
1.3130 + // Collect the simple root for this thread before we
1.3131 + // collect its stack roots
1.3132 + if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
1.3133 + threadObj)) {
1.3134 + return false;
1.3135 + }
1.3136 + if (!collect_stack_roots(thread, &blk)) {
1.3137 + return false;
1.3138 + }
1.3139 + }
1.3140 + }
1.3141 + return true;
1.3142 +}
1.3143 +
1.3144 +// visit an object
1.3145 +// first mark the object as visited
1.3146 +// second get all the outbound references from this object (in other words, all
1.3147 +// the objects referenced by this object).
1.3148 +//
1.3149 +bool VM_HeapWalkOperation::visit(oop o) {
1.3150 + // mark object as visited
1.3151 + assert(!ObjectMarker::visited(o), "can't visit same object more than once");
1.3152 + ObjectMarker::mark(o);
1.3153 +
1.3154 + // instance
1.3155 + if (o->is_instance()) {
1.3156 + if (o->klass() == SystemDictionary::Class_klass()) {
1.3157 + if (!java_lang_Class::is_primitive(o)) {
1.3158 + // a java.lang.Class
1.3159 + return iterate_over_class(o);
1.3160 + }
1.3161 + } else {
1.3162 + return iterate_over_object(o);
1.3163 + }
1.3164 + }
1.3165 +
1.3166 + // object array
1.3167 + if (o->is_objArray()) {
1.3168 + return iterate_over_array(o);
1.3169 + }
1.3170 +
1.3171 + // type array
1.3172 + if (o->is_typeArray()) {
1.3173 + return iterate_over_type_array(o);
1.3174 + }
1.3175 +
1.3176 + return true;
1.3177 +}
1.3178 +
1.3179 +void VM_HeapWalkOperation::doit() {
1.3180 + ResourceMark rm;
1.3181 + ObjectMarkerController marker;
1.3182 + ClassFieldMapCacheMark cm;
1.3183 +
1.3184 + assert(visit_stack()->is_empty(), "visit stack must be empty");
1.3185 +
1.3186 + // the heap walk starts with an initial object or the heap roots
1.3187 + if (initial_object().is_null()) {
1.3188 + // If either collect_stack_roots() or collect_simple_roots()
1.3189 + // returns false at this point, then there are no mark bits
1.3190 + // to reset.
1.3191 + ObjectMarker::set_needs_reset(false);
1.3192 +
1.3193 + // Calling collect_stack_roots() before collect_simple_roots()
1.3194 + // can result in a big performance boost for an agent that is
1.3195 + // focused on analyzing references in the thread stacks.
1.3196 + if (!collect_stack_roots()) return;
1.3197 +
1.3198 + if (!collect_simple_roots()) return;
1.3199 +
1.3200 + // no early return so enable heap traversal to reset the mark bits
1.3201 + ObjectMarker::set_needs_reset(true);
1.3202 + } else {
1.3203 + visit_stack()->push(initial_object()());
1.3204 + }
1.3205 +
1.3206 + // object references required
1.3207 + if (is_following_references()) {
1.3208 +
1.3209 + // visit each object until all reachable objects have been
1.3210 + // visited or the callback asked to terminate the iteration.
1.3211 + while (!visit_stack()->is_empty()) {
1.3212 + oop o = visit_stack()->pop();
1.3213 + if (!ObjectMarker::visited(o)) {
1.3214 + if (!visit(o)) {
1.3215 + break;
1.3216 + }
1.3217 + }
1.3218 + }
1.3219 + }
1.3220 +}
1.3221 +
1.3222 +// iterate over all objects that are reachable from a set of roots
1.3223 +void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
1.3224 + jvmtiStackReferenceCallback stack_ref_callback,
1.3225 + jvmtiObjectReferenceCallback object_ref_callback,
1.3226 + const void* user_data) {
1.3227 + MutexLocker ml(Heap_lock);
1.3228 + BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
1.3229 + VM_HeapWalkOperation op(this, Handle(), context, user_data);
1.3230 + VMThread::execute(&op);
1.3231 +}
1.3232 +
1.3233 +// iterate over all objects that are reachable from a given object
1.3234 +void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
1.3235 + jvmtiObjectReferenceCallback object_ref_callback,
1.3236 + const void* user_data) {
1.3237 + oop obj = JNIHandles::resolve(object);
1.3238 + Handle initial_object(Thread::current(), obj);
1.3239 +
1.3240 + MutexLocker ml(Heap_lock);
1.3241 + BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
1.3242 + VM_HeapWalkOperation op(this, initial_object, context, user_data);
1.3243 + VMThread::execute(&op);
1.3244 +}
1.3245 +
1.3246 +// follow references from an initial object or the GC roots
1.3247 +void JvmtiTagMap::follow_references(jint heap_filter,
1.3248 + KlassHandle klass,
1.3249 + jobject object,
1.3250 + const jvmtiHeapCallbacks* callbacks,
1.3251 + const void* user_data)
1.3252 +{
1.3253 + oop obj = JNIHandles::resolve(object);
1.3254 + Handle initial_object(Thread::current(), obj);
1.3255 +
1.3256 + MutexLocker ml(Heap_lock);
1.3257 + AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
1.3258 + VM_HeapWalkOperation op(this, initial_object, context, user_data);
1.3259 + VMThread::execute(&op);
1.3260 +}
1.3261 +
1.3262 +
1.3263 +void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
1.3264 + // No locks during VM bring-up (0 threads) and no safepoints after main
1.3265 + // thread creation and before VMThread creation (1 thread); initial GC
1.3266 + // verification can happen in that window which gets to here.
1.3267 + assert(Threads::number_of_threads() <= 1 ||
1.3268 + SafepointSynchronize::is_at_safepoint(),
1.3269 + "must be executed at a safepoint");
1.3270 + if (JvmtiEnv::environments_might_exist()) {
1.3271 + JvmtiEnvIterator it;
1.3272 + for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
1.3273 + JvmtiTagMap* tag_map = env->tag_map();
1.3274 + if (tag_map != NULL && !tag_map->is_empty()) {
1.3275 + tag_map->do_weak_oops(is_alive, f);
1.3276 + }
1.3277 + }
1.3278 + }
1.3279 +}
1.3280 +
1.3281 +void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
1.3282 +
1.3283 + // does this environment have the OBJECT_FREE event enabled
1.3284 + bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE);
1.3285 +
1.3286 + // counters used for trace message
1.3287 + int freed = 0;
1.3288 + int moved = 0;
1.3289 +
1.3290 + JvmtiTagHashmap* hashmap = this->hashmap();
1.3291 +
1.3292 + // reenable sizing (if disabled)
1.3293 + hashmap->set_resizing_enabled(true);
1.3294 +
1.3295 + // if the hashmap is empty then we can skip it
1.3296 + if (hashmap->_entry_count == 0) {
1.3297 + return;
1.3298 + }
1.3299 +
1.3300 + // now iterate through each entry in the table
1.3301 +
1.3302 + JvmtiTagHashmapEntry** table = hashmap->table();
1.3303 + int size = hashmap->size();
1.3304 +
1.3305 + JvmtiTagHashmapEntry* delayed_add = NULL;
1.3306 +
1.3307 + for (int pos = 0; pos < size; ++pos) {
1.3308 + JvmtiTagHashmapEntry* entry = table[pos];
1.3309 + JvmtiTagHashmapEntry* prev = NULL;
1.3310 +
1.3311 + while (entry != NULL) {
1.3312 + JvmtiTagHashmapEntry* next = entry->next();
1.3313 +
1.3314 + oop* obj = entry->object_addr();
1.3315 +
1.3316 + // has object been GC'ed
1.3317 + if (!is_alive->do_object_b(entry->object())) {
1.3318 + // grab the tag
1.3319 + jlong tag = entry->tag();
1.3320 + guarantee(tag != 0, "checking");
1.3321 +
1.3322 + // remove GC'ed entry from hashmap and return the
1.3323 + // entry to the free list
1.3324 + hashmap->remove(prev, pos, entry);
1.3325 + destroy_entry(entry);
1.3326 +
1.3327 + // post the event to the profiler
1.3328 + if (post_object_free) {
1.3329 + JvmtiExport::post_object_free(env(), tag);
1.3330 + }
1.3331 +
1.3332 + ++freed;
1.3333 + } else {
1.3334 + f->do_oop(entry->object_addr());
1.3335 + oop new_oop = entry->object();
1.3336 +
1.3337 + // if the object has moved then re-hash it and move its
1.3338 + // entry to its new location.
1.3339 + unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size);
1.3340 + if (new_pos != (unsigned int)pos) {
1.3341 + if (prev == NULL) {
1.3342 + table[pos] = next;
1.3343 + } else {
1.3344 + prev->set_next(next);
1.3345 + }
1.3346 + if (new_pos < (unsigned int)pos) {
1.3347 + entry->set_next(table[new_pos]);
1.3348 + table[new_pos] = entry;
1.3349 + } else {
1.3350 + // Delay adding this entry to it's new position as we'd end up
1.3351 + // hitting it again during this iteration.
1.3352 + entry->set_next(delayed_add);
1.3353 + delayed_add = entry;
1.3354 + }
1.3355 + moved++;
1.3356 + } else {
1.3357 + // object didn't move
1.3358 + prev = entry;
1.3359 + }
1.3360 + }
1.3361 +
1.3362 + entry = next;
1.3363 + }
1.3364 + }
1.3365 +
1.3366 + // Re-add all the entries which were kept aside
1.3367 + while (delayed_add != NULL) {
1.3368 + JvmtiTagHashmapEntry* next = delayed_add->next();
1.3369 + unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object(), size);
1.3370 + delayed_add->set_next(table[pos]);
1.3371 + table[pos] = delayed_add;
1.3372 + delayed_add = next;
1.3373 + }
1.3374 +
1.3375 + // stats
1.3376 + if (TraceJVMTIObjectTagging) {
1.3377 + int post_total = hashmap->_entry_count;
1.3378 + int pre_total = post_total + freed;
1.3379 +
1.3380 + tty->print_cr("(%d->%d, %d freed, %d total moves)",
1.3381 + pre_total, post_total, freed, moved);
1.3382 + }
1.3383 +}
