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
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29 * questions.
30 */
31
32#include <functional>
33
34#include "deopt_manager.h"
35
36#include "art_jvmti.h"
37#include "art_method-inl.h"
38#include "base/enums.h"
39#include "base/mutex-inl.h"
40#include "dex/dex_file_annotations.h"
41#include "dex/modifiers.h"
42#include "events-inl.h"
43#include "jit/jit.h"
44#include "jni_internal.h"
45#include "mirror/class-inl.h"
46#include "mirror/object_array-inl.h"
47#include "nativehelper/scoped_local_ref.h"
48#include "runtime_callbacks.h"
49#include "scoped_thread_state_change-inl.h"
50#include "thread-current-inl.h"
51#include "thread_list.h"
52#include "ti_phase.h"
53
54namespace openjdkjvmti {
55
56// TODO We should make this much more selective in the future so we only return true when we
57// actually care about the method at this time (ie active frames had locals changed). For now we
58// just assume that if anything has changed any frame's locals we care about all methods. If nothing
59// has we only care about methods with active breakpoints on them. In the future we should probably
60// rewrite all of this to instead do this at the ShadowFrame or thread granularity.
61bool JvmtiMethodInspectionCallback::IsMethodBeingInspected(art::ArtMethod* method) {
62  // Non-java-debuggable runtimes we need to assume that any method might not be debuggable and
63  // therefore potentially being inspected (due to inlines). If we are debuggable we rely hard on
64  // inlining not being done since we don't keep track of which methods get inlined where and simply
65  // look to see if the method is breakpointed.
66  return !art::Runtime::Current()->IsJavaDebuggable() ||
67      manager_->HaveLocalsChanged() ||
68      manager_->MethodHasBreakpoints(method);
69}
70
71bool JvmtiMethodInspectionCallback::IsMethodSafeToJit(art::ArtMethod* method) {
72  return !manager_->MethodHasBreakpoints(method);
73}
74
75bool JvmtiMethodInspectionCallback::MethodNeedsDebugVersion(
76    art::ArtMethod* method ATTRIBUTE_UNUSED) {
77  return true;
78}
79
80DeoptManager::DeoptManager()
81  : deoptimization_status_lock_("JVMTI_DeoptimizationStatusLock",
82                                static_cast<art::LockLevel>(
83                                    art::LockLevel::kClassLinkerClassesLock + 1)),
84    deoptimization_condition_("JVMTI_DeoptimizationCondition", deoptimization_status_lock_),
85    performing_deoptimization_(false),
86    global_deopt_count_(0),
87    deopter_count_(0),
88    breakpoint_status_lock_("JVMTI_BreakpointStatusLock",
89                            static_cast<art::LockLevel>(art::LockLevel::kAbortLock + 1)),
90    inspection_callback_(this),
91    set_local_variable_called_(false) { }
92
93void DeoptManager::Setup() {
94  art::ScopedThreadStateChange stsc(art::Thread::Current(),
95                                    art::ThreadState::kWaitingForDebuggerToAttach);
96  art::ScopedSuspendAll ssa("Add method Inspection Callback");
97  art::RuntimeCallbacks* callbacks = art::Runtime::Current()->GetRuntimeCallbacks();
98  callbacks->AddMethodInspectionCallback(&inspection_callback_);
99}
100
101void DeoptManager::Shutdown() {
102  art::ScopedThreadStateChange stsc(art::Thread::Current(),
103                                    art::ThreadState::kWaitingForDebuggerToAttach);
104  art::ScopedSuspendAll ssa("remove method Inspection Callback");
105  art::RuntimeCallbacks* callbacks = art::Runtime::Current()->GetRuntimeCallbacks();
106  callbacks->RemoveMethodInspectionCallback(&inspection_callback_);
107}
108
109void DeoptManager::FinishSetup() {
110  art::Thread* self = art::Thread::Current();
111  art::MutexLock mu(self, deoptimization_status_lock_);
112
113  art::Runtime* runtime = art::Runtime::Current();
114  // See if we need to do anything.
115  if (!runtime->IsJavaDebuggable()) {
116    // See if we can enable all JVMTI functions. If this is false, only kArtTiVersion agents can be
117    // retrieved and they will all be best-effort.
118    if (PhaseUtil::GetPhaseUnchecked() == JVMTI_PHASE_ONLOAD) {
119      // We are still early enough to change the compiler options and get full JVMTI support.
120      LOG(INFO) << "Openjdkjvmti plugin loaded on a non-debuggable runtime. Changing runtime to "
121                << "debuggable state. Please pass '--debuggable' to dex2oat and "
122                << "'-Xcompiler-option --debuggable' to dalvikvm in the future.";
123      DCHECK(runtime->GetJit() == nullptr) << "Jit should not be running yet!";
124      runtime->AddCompilerOption("--debuggable");
125      runtime->SetJavaDebuggable(true);
126    } else {
127      LOG(WARNING) << "Openjdkjvmti plugin was loaded on a non-debuggable Runtime. Plugin was "
128                   << "loaded too late to change runtime state to DEBUGGABLE. Only kArtTiVersion "
129                   << "(0x" << std::hex << kArtTiVersion << ") environments are available. Some "
130                   << "functionality might not work properly.";
131      if (runtime->GetJit() == nullptr &&
132          runtime->GetJITOptions()->UseJitCompilation() &&
133          !runtime->GetInstrumentation()->IsForcedInterpretOnly()) {
134        // If we don't have a jit we should try to start the jit for performance reasons. We only
135        // need to do this for late attach on non-debuggable processes because for debuggable
136        // processes we already rely on jit and we cannot force this jit to start if we are still in
137        // OnLoad since the runtime hasn't started up sufficiently. This is only expected to happen
138        // on userdebug/eng builds.
139        LOG(INFO) << "Attempting to start jit for openjdkjvmti plugin.";
140        runtime->CreateJit();
141        if (runtime->GetJit() == nullptr) {
142          LOG(WARNING) << "Could not start jit for openjdkjvmti plugin. This process might be "
143                       << "quite slow as it is running entirely in the interpreter. Try running "
144                       << "'setenforce 0' and restarting this process.";
145        }
146      }
147    }
148    runtime->DeoptimizeBootImage();
149  }
150}
151
152bool DeoptManager::MethodHasBreakpoints(art::ArtMethod* method) {
153  art::MutexLock lk(art::Thread::Current(), breakpoint_status_lock_);
154  return MethodHasBreakpointsLocked(method);
155}
156
157bool DeoptManager::MethodHasBreakpointsLocked(art::ArtMethod* method) {
158  auto elem = breakpoint_status_.find(method);
159  return elem != breakpoint_status_.end() && elem->second != 0;
160}
161
162void DeoptManager::RemoveDeoptimizeAllMethods() {
163  art::Thread* self = art::Thread::Current();
164  art::ScopedThreadSuspension sts(self, art::kSuspended);
165  deoptimization_status_lock_.ExclusiveLock(self);
166  RemoveDeoptimizeAllMethodsLocked(self);
167}
168
169void DeoptManager::AddDeoptimizeAllMethods() {
170  art::Thread* self = art::Thread::Current();
171  art::ScopedThreadSuspension sts(self, art::kSuspended);
172  deoptimization_status_lock_.ExclusiveLock(self);
173  AddDeoptimizeAllMethodsLocked(self);
174}
175
176void DeoptManager::AddMethodBreakpoint(art::ArtMethod* method) {
177  DCHECK(method->IsInvokable());
178  DCHECK(!method->IsProxyMethod()) << method->PrettyMethod();
179  DCHECK(!method->IsNative()) << method->PrettyMethod();
180
181  art::Thread* self = art::Thread::Current();
182  method = method->GetCanonicalMethod();
183  bool is_default = method->IsDefault();
184
185  art::ScopedThreadSuspension sts(self, art::kSuspended);
186  deoptimization_status_lock_.ExclusiveLock(self);
187  {
188    breakpoint_status_lock_.ExclusiveLock(self);
189
190    DCHECK_GT(deopter_count_, 0u) << "unexpected deotpimization request";
191
192    if (MethodHasBreakpointsLocked(method)) {
193      // Don't need to do anything extra.
194      breakpoint_status_[method]++;
195      // Another thread might be deoptimizing the very method we just added new breakpoints for.
196      // Wait for any deopts to finish before moving on.
197      breakpoint_status_lock_.ExclusiveUnlock(self);
198      WaitForDeoptimizationToFinish(self);
199      return;
200    }
201    breakpoint_status_[method] = 1;
202    breakpoint_status_lock_.ExclusiveUnlock(self);
203  }
204  auto instrumentation = art::Runtime::Current()->GetInstrumentation();
205  if (instrumentation->IsForcedInterpretOnly()) {
206    // We are already interpreting everything so no need to do anything.
207    deoptimization_status_lock_.ExclusiveUnlock(self);
208    return;
209  } else if (is_default) {
210    AddDeoptimizeAllMethodsLocked(self);
211  } else {
212    PerformLimitedDeoptimization(self, method);
213  }
214}
215
216void DeoptManager::RemoveMethodBreakpoint(art::ArtMethod* method) {
217  DCHECK(method->IsInvokable()) << method->PrettyMethod();
218  DCHECK(!method->IsProxyMethod()) << method->PrettyMethod();
219  DCHECK(!method->IsNative()) << method->PrettyMethod();
220
221  art::Thread* self = art::Thread::Current();
222  method = method->GetCanonicalMethod();
223  bool is_default = method->IsDefault();
224
225  art::ScopedThreadSuspension sts(self, art::kSuspended);
226  // Ideally we should do a ScopedSuspendAll right here to get the full mutator_lock_ that we might
227  // need but since that is very heavy we will instead just use a condition variable to make sure we
228  // don't race with ourselves.
229  deoptimization_status_lock_.ExclusiveLock(self);
230  bool is_last_breakpoint;
231  {
232    art::MutexLock mu(self, breakpoint_status_lock_);
233
234    DCHECK_GT(deopter_count_, 0u) << "unexpected deotpimization request";
235    DCHECK(MethodHasBreakpointsLocked(method)) << "Breakpoint on a method was removed without "
236                                              << "breakpoints present!";
237    breakpoint_status_[method] -= 1;
238    is_last_breakpoint = (breakpoint_status_[method] == 0);
239  }
240  auto instrumentation = art::Runtime::Current()->GetInstrumentation();
241  if (UNLIKELY(instrumentation->IsForcedInterpretOnly())) {
242    // We don't need to do anything since we are interpreting everything anyway.
243    deoptimization_status_lock_.ExclusiveUnlock(self);
244    return;
245  } else if (is_last_breakpoint) {
246    if (UNLIKELY(is_default)) {
247      RemoveDeoptimizeAllMethodsLocked(self);
248    } else {
249      PerformLimitedUndeoptimization(self, method);
250    }
251  } else {
252    // Another thread might be deoptimizing the very methods we just removed breakpoints from. Wait
253    // for any deopts to finish before moving on.
254    WaitForDeoptimizationToFinish(self);
255  }
256}
257
258void DeoptManager::WaitForDeoptimizationToFinishLocked(art::Thread* self) {
259  while (performing_deoptimization_) {
260    deoptimization_condition_.Wait(self);
261  }
262}
263
264void DeoptManager::WaitForDeoptimizationToFinish(art::Thread* self) {
265  WaitForDeoptimizationToFinishLocked(self);
266  deoptimization_status_lock_.ExclusiveUnlock(self);
267}
268
269class ScopedDeoptimizationContext : public art::ValueObject {
270 public:
271  ScopedDeoptimizationContext(art::Thread* self, DeoptManager* deopt)
272      RELEASE(deopt->deoptimization_status_lock_)
273      ACQUIRE(art::Locks::mutator_lock_)
274      ACQUIRE(art::Roles::uninterruptible_)
275      : self_(self), deopt_(deopt), uninterruptible_cause_(nullptr) {
276    deopt_->WaitForDeoptimizationToFinishLocked(self_);
277    DCHECK(!deopt->performing_deoptimization_)
278        << "Already performing deoptimization on another thread!";
279    // Use performing_deoptimization_ to keep track of the lock.
280    deopt_->performing_deoptimization_ = true;
281    deopt_->deoptimization_status_lock_.Unlock(self_);
282    art::Runtime::Current()->GetThreadList()->SuspendAll("JMVTI Deoptimizing methods",
283                                                         /*long_suspend*/ false);
284    uninterruptible_cause_ = self_->StartAssertNoThreadSuspension("JVMTI deoptimizing methods");
285  }
286
287  ~ScopedDeoptimizationContext()
288      RELEASE(art::Locks::mutator_lock_)
289      RELEASE(art::Roles::uninterruptible_) {
290    // Can be suspended again.
291    self_->EndAssertNoThreadSuspension(uninterruptible_cause_);
292    // Release the mutator lock.
293    art::Runtime::Current()->GetThreadList()->ResumeAll();
294    // Let other threads know it's fine to proceed.
295    art::MutexLock lk(self_, deopt_->deoptimization_status_lock_);
296    deopt_->performing_deoptimization_ = false;
297    deopt_->deoptimization_condition_.Broadcast(self_);
298  }
299
300 private:
301  art::Thread* self_;
302  DeoptManager* deopt_;
303  const char* uninterruptible_cause_;
304};
305
306void DeoptManager::AddDeoptimizeAllMethodsLocked(art::Thread* self) {
307  global_deopt_count_++;
308  if (global_deopt_count_ == 1) {
309    PerformGlobalDeoptimization(self);
310  } else {
311    WaitForDeoptimizationToFinish(self);
312  }
313}
314
315void DeoptManager::RemoveDeoptimizeAllMethodsLocked(art::Thread* self) {
316  DCHECK_GT(global_deopt_count_, 0u) << "Request to remove non-existent global deoptimization!";
317  global_deopt_count_--;
318  if (global_deopt_count_ == 0) {
319    PerformGlobalUndeoptimization(self);
320  } else {
321    WaitForDeoptimizationToFinish(self);
322  }
323}
324
325void DeoptManager::PerformLimitedDeoptimization(art::Thread* self, art::ArtMethod* method) {
326  ScopedDeoptimizationContext sdc(self, this);
327  art::Runtime::Current()->GetInstrumentation()->Deoptimize(method);
328}
329
330void DeoptManager::PerformLimitedUndeoptimization(art::Thread* self, art::ArtMethod* method) {
331  ScopedDeoptimizationContext sdc(self, this);
332  art::Runtime::Current()->GetInstrumentation()->Undeoptimize(method);
333}
334
335void DeoptManager::PerformGlobalDeoptimization(art::Thread* self) {
336  ScopedDeoptimizationContext sdc(self, this);
337  art::Runtime::Current()->GetInstrumentation()->DeoptimizeEverything(
338      kDeoptManagerInstrumentationKey);
339}
340
341void DeoptManager::PerformGlobalUndeoptimization(art::Thread* self) {
342  ScopedDeoptimizationContext sdc(self, this);
343  art::Runtime::Current()->GetInstrumentation()->UndeoptimizeEverything(
344      kDeoptManagerInstrumentationKey);
345}
346
347
348void DeoptManager::RemoveDeoptimizationRequester() {
349  art::Thread* self = art::Thread::Current();
350  art::ScopedThreadStateChange sts(self, art::kSuspended);
351  deoptimization_status_lock_.ExclusiveLock(self);
352  DCHECK_GT(deopter_count_, 0u) << "Removing deoptimization requester without any being present";
353  deopter_count_--;
354  if (deopter_count_ == 0) {
355    ScopedDeoptimizationContext sdc(self, this);
356    // TODO Give this a real key.
357    art::Runtime::Current()->GetInstrumentation()->DisableDeoptimization("");
358    return;
359  } else {
360    deoptimization_status_lock_.ExclusiveUnlock(self);
361  }
362}
363
364void DeoptManager::AddDeoptimizationRequester() {
365  art::Thread* self = art::Thread::Current();
366  art::ScopedThreadStateChange stsc(self, art::kSuspended);
367  deoptimization_status_lock_.ExclusiveLock(self);
368  deopter_count_++;
369  if (deopter_count_ == 1) {
370    ScopedDeoptimizationContext sdc(self, this);
371    art::Runtime::Current()->GetInstrumentation()->EnableDeoptimization();
372    return;
373  } else {
374    deoptimization_status_lock_.ExclusiveUnlock(self);
375  }
376}
377
378void DeoptManager::DeoptimizeThread(art::Thread* target) {
379  art::Runtime::Current()->GetInstrumentation()->InstrumentThreadStack(target);
380}
381
382extern DeoptManager* gDeoptManager;
383DeoptManager* DeoptManager::Get() {
384  return gDeoptManager;
385}
386
387}  // namespace openjdkjvmti
388