Andreas Gampe | f014021 | 2017-03-03 13:28:58 -0800 | [diff] [blame^] | 1 | /* Copyright (C) 2017 The Android Open Source Project |
| 2 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 3 | * |
| 4 | * This file implements interfaces from the file jvmti.h. This implementation |
| 5 | * is licensed under the same terms as the file jvmti.h. The |
| 6 | * copyright and license information for the file jvmti.h follows. |
| 7 | * |
| 8 | * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved. |
| 9 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 10 | * |
| 11 | * This code is free software; you can redistribute it and/or modify it |
| 12 | * under the terms of the GNU General Public License version 2 only, as |
| 13 | * published by the Free Software Foundation. Oracle designates this |
| 14 | * particular file as subject to the "Classpath" exception as provided |
| 15 | * by Oracle in the LICENSE file that accompanied this code. |
| 16 | * |
| 17 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 18 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 19 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 20 | * version 2 for more details (a copy is included in the LICENSE file that |
| 21 | * accompanied this code). |
| 22 | * |
| 23 | * You should have received a copy of the GNU General Public License version |
| 24 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 25 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 26 | * |
| 27 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| 28 | * or visit www.oracle.com if you need additional information or have any |
| 29 | * questions. |
| 30 | */ |
| 31 | |
| 32 | #ifndef ART_RUNTIME_OPENJDKJVMTI_JVMTI_WEAK_TABLE_INL_H_ |
| 33 | #define ART_RUNTIME_OPENJDKJVMTI_JVMTI_WEAK_TABLE_INL_H_ |
| 34 | |
| 35 | #include "jvmti_weak_table.h" |
| 36 | |
| 37 | #include <limits> |
| 38 | |
| 39 | #include "art_jvmti.h" |
| 40 | #include "base/logging.h" |
| 41 | #include "gc/allocation_listener.h" |
| 42 | #include "instrumentation.h" |
| 43 | #include "jni_env_ext-inl.h" |
| 44 | #include "jvmti_allocator.h" |
| 45 | #include "mirror/class.h" |
| 46 | #include "mirror/object.h" |
| 47 | #include "runtime.h" |
| 48 | #include "ScopedLocalRef.h" |
| 49 | |
| 50 | namespace openjdkjvmti { |
| 51 | |
| 52 | template <typename T> |
| 53 | void JvmtiWeakTable<T>::Lock() { |
| 54 | allow_disallow_lock_.ExclusiveLock(art::Thread::Current()); |
| 55 | } |
| 56 | template <typename T> |
| 57 | void JvmtiWeakTable<T>::Unlock() { |
| 58 | allow_disallow_lock_.ExclusiveUnlock(art::Thread::Current()); |
| 59 | } |
| 60 | template <typename T> |
| 61 | void JvmtiWeakTable<T>::AssertLocked() { |
| 62 | allow_disallow_lock_.AssertHeld(art::Thread::Current()); |
| 63 | } |
| 64 | |
| 65 | template <typename T> |
| 66 | void JvmtiWeakTable<T>::UpdateTableWithReadBarrier() { |
| 67 | update_since_last_sweep_ = true; |
| 68 | |
| 69 | auto WithReadBarrierUpdater = [&](const art::GcRoot<art::mirror::Object>& original_root, |
| 70 | art::mirror::Object* original_obj ATTRIBUTE_UNUSED) |
| 71 | REQUIRES_SHARED(art::Locks::mutator_lock_) { |
| 72 | return original_root.Read<art::kWithReadBarrier>(); |
| 73 | }; |
| 74 | |
| 75 | UpdateTableWith<decltype(WithReadBarrierUpdater), kIgnoreNull>(WithReadBarrierUpdater); |
| 76 | } |
| 77 | |
| 78 | template <typename T> |
| 79 | bool JvmtiWeakTable<T>::GetTagSlowPath(art::Thread* self, art::mirror::Object* obj, T* result) { |
| 80 | // Under concurrent GC, there is a window between moving objects and sweeping of system |
| 81 | // weaks in which mutators are active. We may receive a to-space object pointer in obj, |
| 82 | // but still have from-space pointers in the table. Explicitly update the table once. |
| 83 | // Note: this will keep *all* objects in the table live, but should be a rare occurrence. |
| 84 | UpdateTableWithReadBarrier(); |
| 85 | return GetTagLocked(self, obj, result); |
| 86 | } |
| 87 | |
| 88 | template <typename T> |
| 89 | bool JvmtiWeakTable<T>::Remove(art::mirror::Object* obj, /* out */ T* tag) { |
| 90 | art::Thread* self = art::Thread::Current(); |
| 91 | art::MutexLock mu(self, allow_disallow_lock_); |
| 92 | Wait(self); |
| 93 | |
| 94 | return RemoveLocked(self, obj, tag); |
| 95 | } |
| 96 | template <typename T> |
| 97 | bool JvmtiWeakTable<T>::RemoveLocked(art::mirror::Object* obj, T* tag) { |
| 98 | art::Thread* self = art::Thread::Current(); |
| 99 | allow_disallow_lock_.AssertHeld(self); |
| 100 | Wait(self); |
| 101 | |
| 102 | return RemoveLocked(self, obj, tag); |
| 103 | } |
| 104 | |
| 105 | template <typename T> |
| 106 | bool JvmtiWeakTable<T>::RemoveLocked(art::Thread* self, art::mirror::Object* obj, T* tag) { |
| 107 | auto it = tagged_objects_.find(art::GcRoot<art::mirror::Object>(obj)); |
| 108 | if (it != tagged_objects_.end()) { |
| 109 | if (tag != nullptr) { |
| 110 | *tag = it->second; |
| 111 | } |
| 112 | tagged_objects_.erase(it); |
| 113 | return true; |
| 114 | } |
| 115 | |
| 116 | if (art::kUseReadBarrier && self->GetIsGcMarking() && !update_since_last_sweep_) { |
| 117 | // Under concurrent GC, there is a window between moving objects and sweeping of system |
| 118 | // weaks in which mutators are active. We may receive a to-space object pointer in obj, |
| 119 | // but still have from-space pointers in the table. Explicitly update the table once. |
| 120 | // Note: this will keep *all* objects in the table live, but should be a rare occurrence. |
| 121 | |
| 122 | // Update the table. |
| 123 | UpdateTableWithReadBarrier(); |
| 124 | |
| 125 | // And try again. |
| 126 | return RemoveLocked(self, obj, tag); |
| 127 | } |
| 128 | |
| 129 | // Not in here. |
| 130 | return false; |
| 131 | } |
| 132 | |
| 133 | template <typename T> |
| 134 | bool JvmtiWeakTable<T>::Set(art::mirror::Object* obj, T new_tag) { |
| 135 | art::Thread* self = art::Thread::Current(); |
| 136 | art::MutexLock mu(self, allow_disallow_lock_); |
| 137 | Wait(self); |
| 138 | |
| 139 | return SetLocked(self, obj, new_tag); |
| 140 | } |
| 141 | template <typename T> |
| 142 | bool JvmtiWeakTable<T>::SetLocked(art::mirror::Object* obj, T new_tag) { |
| 143 | art::Thread* self = art::Thread::Current(); |
| 144 | allow_disallow_lock_.AssertHeld(self); |
| 145 | Wait(self); |
| 146 | |
| 147 | return SetLocked(self, obj, new_tag); |
| 148 | } |
| 149 | |
| 150 | template <typename T> |
| 151 | bool JvmtiWeakTable<T>::SetLocked(art::Thread* self, art::mirror::Object* obj, T new_tag) { |
| 152 | auto it = tagged_objects_.find(art::GcRoot<art::mirror::Object>(obj)); |
| 153 | if (it != tagged_objects_.end()) { |
| 154 | it->second = new_tag; |
| 155 | return true; |
| 156 | } |
| 157 | |
| 158 | if (art::kUseReadBarrier && self->GetIsGcMarking() && !update_since_last_sweep_) { |
| 159 | // Under concurrent GC, there is a window between moving objects and sweeping of system |
| 160 | // weaks in which mutators are active. We may receive a to-space object pointer in obj, |
| 161 | // but still have from-space pointers in the table. Explicitly update the table once. |
| 162 | // Note: this will keep *all* objects in the table live, but should be a rare occurrence. |
| 163 | |
| 164 | // Update the table. |
| 165 | UpdateTableWithReadBarrier(); |
| 166 | |
| 167 | // And try again. |
| 168 | return SetLocked(self, obj, new_tag); |
| 169 | } |
| 170 | |
| 171 | // New element. |
| 172 | auto insert_it = tagged_objects_.emplace(art::GcRoot<art::mirror::Object>(obj), new_tag); |
| 173 | DCHECK(insert_it.second); |
| 174 | return false; |
| 175 | } |
| 176 | |
| 177 | template <typename T> |
| 178 | void JvmtiWeakTable<T>::Sweep(art::IsMarkedVisitor* visitor) { |
| 179 | if (DoesHandleNullOnSweep()) { |
| 180 | SweepImpl<true>(visitor); |
| 181 | } else { |
| 182 | SweepImpl<false>(visitor); |
| 183 | } |
| 184 | |
| 185 | // Under concurrent GC, there is a window between moving objects and sweeping of system |
| 186 | // weaks in which mutators are active. We may receive a to-space object pointer in obj, |
| 187 | // but still have from-space pointers in the table. We explicitly update the table then |
| 188 | // to ensure we compare against to-space pointers. But we want to do this only once. Once |
| 189 | // sweeping is done, we know all objects are to-space pointers until the next GC cycle, |
| 190 | // so we re-enable the explicit update for the next marking. |
| 191 | update_since_last_sweep_ = false; |
| 192 | } |
| 193 | |
| 194 | template <typename T> |
| 195 | template <bool kHandleNull> |
| 196 | void JvmtiWeakTable<T>::SweepImpl(art::IsMarkedVisitor* visitor) { |
| 197 | art::Thread* self = art::Thread::Current(); |
| 198 | art::MutexLock mu(self, allow_disallow_lock_); |
| 199 | |
| 200 | auto IsMarkedUpdater = [&](const art::GcRoot<art::mirror::Object>& original_root ATTRIBUTE_UNUSED, |
| 201 | art::mirror::Object* original_obj) { |
| 202 | return visitor->IsMarked(original_obj); |
| 203 | }; |
| 204 | |
| 205 | UpdateTableWith<decltype(IsMarkedUpdater), |
| 206 | kHandleNull ? kCallHandleNull : kRemoveNull>(IsMarkedUpdater); |
| 207 | } |
| 208 | |
| 209 | template <typename T> |
| 210 | template <typename Updater, typename JvmtiWeakTable<T>::TableUpdateNullTarget kTargetNull> |
| 211 | ALWAYS_INLINE inline void JvmtiWeakTable<T>::UpdateTableWith(Updater& updater) { |
| 212 | // We optimistically hope that elements will still be well-distributed when re-inserting them. |
| 213 | // So play with the map mechanics, and postpone rehashing. This avoids the need of a side |
| 214 | // vector and two passes. |
| 215 | float original_max_load_factor = tagged_objects_.max_load_factor(); |
| 216 | tagged_objects_.max_load_factor(std::numeric_limits<float>::max()); |
| 217 | // For checking that a max load-factor actually does what we expect. |
| 218 | size_t original_bucket_count = tagged_objects_.bucket_count(); |
| 219 | |
| 220 | for (auto it = tagged_objects_.begin(); it != tagged_objects_.end();) { |
| 221 | DCHECK(!it->first.IsNull()); |
| 222 | art::mirror::Object* original_obj = it->first.template Read<art::kWithoutReadBarrier>(); |
| 223 | art::mirror::Object* target_obj = updater(it->first, original_obj); |
| 224 | if (original_obj != target_obj) { |
| 225 | if (kTargetNull == kIgnoreNull && target_obj == nullptr) { |
| 226 | // Ignore null target, don't do anything. |
| 227 | } else { |
| 228 | T tag = it->second; |
| 229 | it = tagged_objects_.erase(it); |
| 230 | if (target_obj != nullptr) { |
| 231 | tagged_objects_.emplace(art::GcRoot<art::mirror::Object>(target_obj), tag); |
| 232 | DCHECK_EQ(original_bucket_count, tagged_objects_.bucket_count()); |
| 233 | } else if (kTargetNull == kCallHandleNull) { |
| 234 | HandleNullSweep(tag); |
| 235 | } |
| 236 | continue; // Iterator was implicitly updated by erase. |
| 237 | } |
| 238 | } |
| 239 | it++; |
| 240 | } |
| 241 | |
| 242 | tagged_objects_.max_load_factor(original_max_load_factor); |
| 243 | // TODO: consider rehash here. |
| 244 | } |
| 245 | |
| 246 | template <typename T> |
| 247 | template <typename Storage, class Allocator> |
| 248 | struct JvmtiWeakTable<T>::ReleasableContainer { |
| 249 | using allocator_type = Allocator; |
| 250 | |
| 251 | explicit ReleasableContainer(const allocator_type& alloc, size_t reserve = 10) |
| 252 | : allocator(alloc), |
| 253 | data(reserve > 0 ? allocator.allocate(reserve) : nullptr), |
| 254 | size(0), |
| 255 | capacity(reserve) { |
| 256 | } |
| 257 | |
| 258 | ~ReleasableContainer() { |
| 259 | if (data != nullptr) { |
| 260 | allocator.deallocate(data, capacity); |
| 261 | capacity = 0; |
| 262 | size = 0; |
| 263 | } |
| 264 | } |
| 265 | |
| 266 | Storage* Release() { |
| 267 | Storage* tmp = data; |
| 268 | |
| 269 | data = nullptr; |
| 270 | size = 0; |
| 271 | capacity = 0; |
| 272 | |
| 273 | return tmp; |
| 274 | } |
| 275 | |
| 276 | void Resize(size_t new_capacity) { |
| 277 | CHECK_GT(new_capacity, capacity); |
| 278 | |
| 279 | Storage* tmp = allocator.allocate(new_capacity); |
| 280 | DCHECK(tmp != nullptr); |
| 281 | if (data != nullptr) { |
| 282 | memcpy(tmp, data, sizeof(Storage) * size); |
| 283 | } |
| 284 | Storage* old = data; |
| 285 | data = tmp; |
| 286 | allocator.deallocate(old, capacity); |
| 287 | capacity = new_capacity; |
| 288 | } |
| 289 | |
| 290 | void Pushback(const Storage& elem) { |
| 291 | if (size == capacity) { |
| 292 | size_t new_capacity = 2 * capacity + 1; |
| 293 | Resize(new_capacity); |
| 294 | } |
| 295 | data[size++] = elem; |
| 296 | } |
| 297 | |
| 298 | Allocator allocator; |
| 299 | Storage* data; |
| 300 | size_t size; |
| 301 | size_t capacity; |
| 302 | }; |
| 303 | |
| 304 | template <typename T> |
| 305 | jvmtiError JvmtiWeakTable<T>::GetTaggedObjects(jvmtiEnv* jvmti_env, |
| 306 | jint tag_count, |
| 307 | const T* tags, |
| 308 | jint* count_ptr, |
| 309 | jobject** object_result_ptr, |
| 310 | T** tag_result_ptr) { |
| 311 | if (tag_count < 0) { |
| 312 | return ERR(ILLEGAL_ARGUMENT); |
| 313 | } |
| 314 | if (tag_count > 0) { |
| 315 | for (size_t i = 0; i != static_cast<size_t>(tag_count); ++i) { |
| 316 | if (tags[i] == 0) { |
| 317 | return ERR(ILLEGAL_ARGUMENT); |
| 318 | } |
| 319 | } |
| 320 | } |
| 321 | if (tags == nullptr) { |
| 322 | return ERR(NULL_POINTER); |
| 323 | } |
| 324 | if (count_ptr == nullptr) { |
| 325 | return ERR(NULL_POINTER); |
| 326 | } |
| 327 | |
| 328 | art::Thread* self = art::Thread::Current(); |
| 329 | art::MutexLock mu(self, allow_disallow_lock_); |
| 330 | Wait(self); |
| 331 | |
| 332 | art::JNIEnvExt* jni_env = self->GetJniEnv(); |
| 333 | |
| 334 | constexpr size_t kDefaultSize = 10; |
| 335 | size_t initial_object_size; |
| 336 | size_t initial_tag_size; |
| 337 | if (tag_count == 0) { |
| 338 | initial_object_size = (object_result_ptr != nullptr) ? tagged_objects_.size() : 0; |
| 339 | initial_tag_size = (tag_result_ptr != nullptr) ? tagged_objects_.size() : 0; |
| 340 | } else { |
| 341 | initial_object_size = initial_tag_size = kDefaultSize; |
| 342 | } |
| 343 | JvmtiAllocator<void> allocator(jvmti_env); |
| 344 | ReleasableContainer<jobject, JvmtiAllocator<jobject>> selected_objects(allocator, |
| 345 | initial_object_size); |
| 346 | ReleasableContainer<T, JvmtiAllocator<T>> selected_tags(allocator, initial_tag_size); |
| 347 | |
| 348 | size_t count = 0; |
| 349 | for (auto& pair : tagged_objects_) { |
| 350 | bool select; |
| 351 | if (tag_count > 0) { |
| 352 | select = false; |
| 353 | for (size_t i = 0; i != static_cast<size_t>(tag_count); ++i) { |
| 354 | if (tags[i] == pair.second) { |
| 355 | select = true; |
| 356 | break; |
| 357 | } |
| 358 | } |
| 359 | } else { |
| 360 | select = true; |
| 361 | } |
| 362 | |
| 363 | if (select) { |
| 364 | art::mirror::Object* obj = pair.first.template Read<art::kWithReadBarrier>(); |
| 365 | if (obj != nullptr) { |
| 366 | count++; |
| 367 | if (object_result_ptr != nullptr) { |
| 368 | selected_objects.Pushback(jni_env->AddLocalReference<jobject>(obj)); |
| 369 | } |
| 370 | if (tag_result_ptr != nullptr) { |
| 371 | selected_tags.Pushback(pair.second); |
| 372 | } |
| 373 | } |
| 374 | } |
| 375 | } |
| 376 | |
| 377 | if (object_result_ptr != nullptr) { |
| 378 | *object_result_ptr = selected_objects.Release(); |
| 379 | } |
| 380 | if (tag_result_ptr != nullptr) { |
| 381 | *tag_result_ptr = selected_tags.Release(); |
| 382 | } |
| 383 | *count_ptr = static_cast<jint>(count); |
| 384 | return ERR(NONE); |
| 385 | } |
| 386 | |
| 387 | } // namespace openjdkjvmti |
| 388 | |
| 389 | #endif // ART_RUNTIME_OPENJDKJVMTI_JVMTI_WEAK_TABLE_INL_H_ |