Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef ART_SRC_SCOPED_THREAD_STATE_CHANGE_H_ |
| 18 | #define ART_SRC_SCOPED_THREAD_STATE_CHANGE_H_ |
| 19 | |
| 20 | #include "casts.h" |
| 21 | #include "thread.h" |
| 22 | |
| 23 | namespace art { |
| 24 | |
| 25 | // Scoped change into and out of a particular state. Handles Runnable transitions that require |
| 26 | // more complicated suspension checking. The subclasses ScopedObjectAccessUnchecked and |
| 27 | // ScopedObjectAccess are used to handle the change into Runnable to get direct access to objects, |
| 28 | // the unchecked variant doesn't aid annotalysis. |
| 29 | class ScopedThreadStateChange { |
| 30 | public: |
| 31 | ScopedThreadStateChange(Thread* self, ThreadState new_thread_state) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 32 | LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_) |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 33 | : self_(self), thread_state_(new_thread_state), expected_has_no_thread_(false) { |
| 34 | if (self_ == NULL) { |
| 35 | // Value chosen arbitrarily and won't be used in the destructor since thread_ == NULL. |
| 36 | old_thread_state_ = kTerminated; |
| 37 | CHECK(!Runtime::Current()->IsStarted() || Runtime::Current()->IsShuttingDown()); |
| 38 | } else { |
| 39 | bool runnable_transition; |
Ian Rogers | 22f454c | 2012-09-08 11:06:29 -0700 | [diff] [blame^] | 40 | DCHECK_EQ(self, Thread::Current()); |
| 41 | // Read state without locks, ok as state is effectively thread local and we're not interested |
| 42 | // in the suspend count (this will be handled in the runnable transitions). |
| 43 | old_thread_state_ = self->GetStateUnsafe(); |
| 44 | runnable_transition = old_thread_state_ == kRunnable || new_thread_state == kRunnable; |
| 45 | if (!runnable_transition) { |
| 46 | // A suspended transition to another effectively suspended transition, ok to use Unsafe. |
| 47 | self_->SetStateUnsafe(new_thread_state); |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 48 | } |
| 49 | if (runnable_transition && old_thread_state_ != new_thread_state) { |
| 50 | if (new_thread_state == kRunnable) { |
| 51 | self_->TransitionFromSuspendedToRunnable(); |
| 52 | } else { |
| 53 | DCHECK_EQ(old_thread_state_, kRunnable); |
| 54 | self_->TransitionFromRunnableToSuspended(new_thread_state); |
| 55 | } |
| 56 | } |
| 57 | } |
| 58 | } |
| 59 | |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 60 | ~ScopedThreadStateChange() LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_) { |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 61 | if (self_ == NULL) { |
| 62 | if (!expected_has_no_thread_) { |
| 63 | CHECK(Runtime::Current()->IsShuttingDown()); |
| 64 | } |
| 65 | } else { |
| 66 | if (old_thread_state_ != thread_state_) { |
| 67 | if (old_thread_state_ == kRunnable) { |
| 68 | self_->TransitionFromSuspendedToRunnable(); |
| 69 | } else if (thread_state_ == kRunnable) { |
| 70 | self_->TransitionFromRunnableToSuspended(old_thread_state_); |
| 71 | } else { |
Ian Rogers | 22f454c | 2012-09-08 11:06:29 -0700 | [diff] [blame^] | 72 | // A suspended transition to another effectively suspended transition, ok to use Unsafe. |
| 73 | self_->SetStateUnsafe(old_thread_state_); |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 74 | } |
| 75 | } |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | Thread* Self() const { |
| 80 | return self_; |
| 81 | } |
| 82 | |
| 83 | protected: |
| 84 | // Constructor used by ScopedJniThreadState for an unattached thread that has access to the VM*. |
| 85 | ScopedThreadStateChange() |
| 86 | : self_(NULL), thread_state_(kTerminated), old_thread_state_(kTerminated), |
| 87 | expected_has_no_thread_(true) {} |
| 88 | |
| 89 | Thread* const self_; |
| 90 | const ThreadState thread_state_; |
| 91 | |
| 92 | private: |
| 93 | ThreadState old_thread_state_; |
| 94 | const bool expected_has_no_thread_; |
| 95 | |
| 96 | DISALLOW_COPY_AND_ASSIGN(ScopedThreadStateChange); |
| 97 | }; |
| 98 | |
| 99 | // Entry/exit processing for transitions from Native to Runnable (ie within JNI functions). |
| 100 | // |
| 101 | // This class performs the necessary thread state switching to and from Runnable and lets us |
| 102 | // amortize the cost of working out the current thread. Additionally it lets us check (and repair) |
| 103 | // apps that are using a JNIEnv on the wrong thread. The class also decodes and encodes Objects |
| 104 | // into jobjects via methods of this class. Performing this here enforces the Runnable thread state |
| 105 | // for use of Object, thereby inhibiting the Object being modified by GC whilst native or VM code |
| 106 | // is also manipulating the Object. |
| 107 | // |
| 108 | // The destructor transitions back to the previous thread state, typically Native. In this state |
| 109 | // GC and thread suspension may occur. |
| 110 | // |
| 111 | // For annotalysis the subclass ScopedObjectAccess (below) makes it explicit that a shared of |
| 112 | // the mutator_lock_ will be acquired on construction. |
| 113 | class ScopedObjectAccessUnchecked : public ScopedThreadStateChange { |
| 114 | public: |
| 115 | explicit ScopedObjectAccessUnchecked(JNIEnv* env) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 116 | LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_) |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 117 | : ScopedThreadStateChange(ThreadForEnv(env), kRunnable), |
| 118 | env_(reinterpret_cast<JNIEnvExt*>(env)), vm_(env_->vm) { |
| 119 | self_->VerifyStack(); |
| 120 | } |
| 121 | |
| 122 | explicit ScopedObjectAccessUnchecked(Thread* self) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 123 | LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_) |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 124 | : ScopedThreadStateChange(self, kRunnable), |
| 125 | env_(reinterpret_cast<JNIEnvExt*>(self->GetJniEnv())), |
| 126 | vm_(env_ != NULL ? env_->vm : NULL) { |
| 127 | if (Vm() != NULL && !Vm()->work_around_app_jni_bugs && self != Thread::Current()) { |
| 128 | UnexpectedThreads(self, Thread::Current()); |
| 129 | } |
| 130 | self_->VerifyStack(); |
| 131 | } |
| 132 | |
| 133 | // Used when we want a scoped JNI thread state but have no thread/JNIEnv. Consequently doesn't |
| 134 | // change into Runnable or acquire a share on the mutator_lock_. |
| 135 | explicit ScopedObjectAccessUnchecked(JavaVM* vm) |
| 136 | : ScopedThreadStateChange(), env_(NULL), vm_(reinterpret_cast<JavaVMExt*>(vm)) {} |
| 137 | |
| 138 | JNIEnvExt* Env() const { |
| 139 | return env_; |
| 140 | } |
| 141 | |
| 142 | JavaVMExt* Vm() const { |
| 143 | return vm_; |
| 144 | } |
| 145 | |
| 146 | /* |
| 147 | * Add a local reference for an object to the indirect reference table associated with the |
| 148 | * current stack frame. When the native function returns, the reference will be discarded. |
| 149 | * Part of the ScopedJniThreadState as native code shouldn't be working on raw Object* without |
| 150 | * having transitioned its state. |
| 151 | * |
| 152 | * We need to allow the same reference to be added multiple times. |
| 153 | * |
| 154 | * This will be called on otherwise unreferenced objects. We cannot do GC allocations here, and |
| 155 | * it's best if we don't grab a mutex. |
| 156 | * |
| 157 | * Returns the local reference (currently just the same pointer that was |
| 158 | * passed in), or NULL on failure. |
| 159 | */ |
| 160 | template<typename T> |
| 161 | T AddLocalReference(Object* obj) const |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 162 | SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 163 | DCHECK_EQ(thread_state_, kRunnable); // Don't work with raw objects in non-runnable states. |
| 164 | if (obj == NULL) { |
| 165 | return NULL; |
| 166 | } |
| 167 | |
| 168 | DCHECK_NE((reinterpret_cast<uintptr_t>(obj) & 0xffff0000), 0xebad0000); |
| 169 | |
| 170 | IndirectReferenceTable& locals = Env()->locals; |
| 171 | |
| 172 | uint32_t cookie = Env()->local_ref_cookie; |
| 173 | IndirectRef ref = locals.Add(cookie, obj); |
| 174 | |
| 175 | #if 0 // TODO: fix this to understand PushLocalFrame, so we can turn it on. |
| 176 | if (Env()->check_jni) { |
| 177 | size_t entry_count = locals.Capacity(); |
| 178 | if (entry_count > 16) { |
| 179 | LOG(WARNING) << "Warning: more than 16 JNI local references: " |
| 180 | << entry_count << " (most recent was a " << PrettyTypeOf(obj) << ")\n" |
| 181 | << Dumpable<IndirectReferenceTable>(locals); |
| 182 | // TODO: LOG(FATAL) in a later release? |
| 183 | } |
| 184 | } |
| 185 | #endif |
| 186 | |
| 187 | if (Vm()->work_around_app_jni_bugs) { |
| 188 | // Hand out direct pointers to support broken old apps. |
| 189 | return reinterpret_cast<T>(obj); |
| 190 | } |
| 191 | |
| 192 | return reinterpret_cast<T>(ref); |
| 193 | } |
| 194 | |
| 195 | template<typename T> |
| 196 | T Decode(jobject obj) const |
| 197 | LOCKS_EXCLUDED(JavaVMExt::globals_lock, |
| 198 | JavaVMExt::weak_globals_lock) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 199 | SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| 200 | Locks::mutator_lock_->AssertSharedHeld(); |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 201 | DCHECK_EQ(thread_state_, kRunnable); // Don't work with raw objects in non-runnable states. |
| 202 | return down_cast<T>(Self()->DecodeJObject(obj)); |
| 203 | } |
| 204 | |
| 205 | Field* DecodeField(jfieldID fid) const |
| 206 | LOCKS_EXCLUDED(JavaVMExt::globals_lock, |
| 207 | JavaVMExt::weak_globals_lock) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 208 | SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| 209 | Locks::mutator_lock_->AssertSharedHeld(); |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 210 | DCHECK_EQ(thread_state_, kRunnable); // Don't work with raw objects in non-runnable states. |
| 211 | #ifdef MOVING_GARBAGE_COLLECTOR |
| 212 | // TODO: we should make these unique weak globals if Field instances can ever move. |
| 213 | UNIMPLEMENTED(WARNING); |
| 214 | #endif |
| 215 | return reinterpret_cast<Field*>(fid); |
| 216 | } |
| 217 | |
| 218 | jfieldID EncodeField(Field* field) const |
| 219 | LOCKS_EXCLUDED(JavaVMExt::globals_lock, |
| 220 | JavaVMExt::weak_globals_lock) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 221 | SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| 222 | Locks::mutator_lock_->AssertSharedHeld(); |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 223 | DCHECK_EQ(thread_state_, kRunnable); // Don't work with raw objects in non-runnable states. |
| 224 | #ifdef MOVING_GARBAGE_COLLECTOR |
| 225 | UNIMPLEMENTED(WARNING); |
| 226 | #endif |
| 227 | return reinterpret_cast<jfieldID>(field); |
| 228 | } |
| 229 | |
| 230 | Method* DecodeMethod(jmethodID mid) const |
| 231 | LOCKS_EXCLUDED(JavaVMExt::globals_lock, |
| 232 | JavaVMExt::weak_globals_lock) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 233 | SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| 234 | Locks::mutator_lock_->AssertSharedHeld(); |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 235 | DCHECK_EQ(thread_state_, kRunnable); // Don't work with raw objects in non-runnable states. |
| 236 | #ifdef MOVING_GARBAGE_COLLECTOR |
| 237 | // TODO: we should make these unique weak globals if Method instances can ever move. |
| 238 | UNIMPLEMENTED(WARNING); |
| 239 | #endif |
| 240 | return reinterpret_cast<Method*>(mid); |
| 241 | } |
| 242 | |
| 243 | jmethodID EncodeMethod(Method* method) const |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 244 | SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { |
| 245 | Locks::mutator_lock_->AssertSharedHeld(); |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 246 | DCHECK_EQ(thread_state_, kRunnable); // Don't work with raw objects in non-runnable states. |
| 247 | #ifdef MOVING_GARBAGE_COLLECTOR |
| 248 | UNIMPLEMENTED(WARNING); |
| 249 | #endif |
| 250 | return reinterpret_cast<jmethodID>(method); |
| 251 | } |
| 252 | |
| 253 | private: |
| 254 | static Thread* ThreadForEnv(JNIEnv* env) { |
| 255 | JNIEnvExt* full_env(reinterpret_cast<JNIEnvExt*>(env)); |
| 256 | bool work_around_app_jni_bugs = full_env->vm->work_around_app_jni_bugs; |
| 257 | Thread* env_self = full_env->self; |
| 258 | Thread* self = work_around_app_jni_bugs ? Thread::Current() : env_self; |
| 259 | if (!work_around_app_jni_bugs && self != env_self) { |
| 260 | UnexpectedThreads(env_self, self); |
| 261 | } |
| 262 | return self; |
| 263 | } |
| 264 | |
| 265 | static void UnexpectedThreads(Thread* found_self, Thread* expected_self) { |
| 266 | // TODO: pass through function name so we can use it here instead of NULL... |
| 267 | JniAbortF(NULL, "JNIEnv for %s used on %s", |
| 268 | found_self != NULL ? ToStr<Thread>(*found_self).c_str() : "NULL", |
| 269 | expected_self != NULL ? ToStr<Thread>(*expected_self).c_str() : "NULL"); |
| 270 | |
| 271 | } |
| 272 | |
| 273 | // The full JNIEnv. |
| 274 | JNIEnvExt* const env_; |
| 275 | // The full JavaVM. |
| 276 | JavaVMExt* const vm_; |
| 277 | |
| 278 | DISALLOW_COPY_AND_ASSIGN(ScopedObjectAccessUnchecked); |
| 279 | }; |
| 280 | |
| 281 | // Annotalysis helping variant of the above. |
| 282 | class ScopedObjectAccess : public ScopedObjectAccessUnchecked { |
| 283 | public: |
| 284 | explicit ScopedObjectAccess(JNIEnv* env) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 285 | LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_) |
| 286 | SHARED_LOCK_FUNCTION(Locks::mutator_lock_) |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 287 | : ScopedObjectAccessUnchecked(env) { |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 288 | Locks::mutator_lock_->AssertSharedHeld(); |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 289 | } |
| 290 | |
| 291 | explicit ScopedObjectAccess(Thread* self) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 292 | LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_) |
| 293 | SHARED_LOCK_FUNCTION(Locks::mutator_lock_) |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 294 | : ScopedObjectAccessUnchecked(self) { |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 295 | Locks::mutator_lock_->AssertSharedHeld(); |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 296 | } |
| 297 | |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 298 | ~ScopedObjectAccess() UNLOCK_FUNCTION(Locks::mutator_lock_) { |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 299 | // Base class will release share of lock. Invoked after this destructor. |
| 300 | } |
| 301 | |
| 302 | private: |
| 303 | // TODO: remove this constructor. It is used by check JNI's ScopedCheck to make it believe that |
| 304 | // routines operating with just a VM are sound, they are not, but when you have just a VM |
| 305 | // you cannot call the unsound routines. |
| 306 | explicit ScopedObjectAccess(JavaVM* vm) |
Ian Rogers | b726dcb | 2012-09-05 08:57:23 -0700 | [diff] [blame] | 307 | SHARED_LOCK_FUNCTION(Locks::mutator_lock_) |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame] | 308 | : ScopedObjectAccessUnchecked(vm) {} |
| 309 | |
| 310 | friend class ScopedCheck; |
| 311 | DISALLOW_COPY_AND_ASSIGN(ScopedObjectAccess); |
| 312 | }; |
| 313 | |
| 314 | } // namespace art |
| 315 | |
| 316 | #endif // ART_SRC_SCOPED_THREAD_STATE_CHANGE_H_ |