trace.cc revision f83e733618066e3c672c9a7ee872a3bba8202e7f 
1/*
2 * Copyright (C) 2011 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#include "trace.h"
18
19#include <sys/uio.h>
20#include <unistd.h>
21
22#define ATRACE_TAG ATRACE_TAG_DALVIK
23#include "cutils/trace.h"
24
25#include "art_method-inl.h"
26#include "base/casts.h"
27#include "base/stl_util.h"
28#include "base/time_utils.h"
29#include "base/unix_file/fd_file.h"
30#include "class_linker.h"
31#include "common_throws.h"
32#include "debugger.h"
33#include "dex_file-inl.h"
34#include "gc/scoped_gc_critical_section.h"
35#include "instrumentation.h"
36#include "mirror/class-inl.h"
37#include "mirror/dex_cache-inl.h"
38#include "mirror/object_array-inl.h"
39#include "mirror/object-inl.h"
40#include "os.h"
41#include "scoped_thread_state_change.h"
42#include "ScopedLocalRef.h"
43#include "thread.h"
44#include "thread_list.h"
45#include "utils.h"
46#include "entrypoints/quick/quick_entrypoints.h"
47
48namespace art {
49
50static constexpr size_t TraceActionBits = MinimumBitsToStore(
51    static_cast<size_t>(kTraceMethodActionMask));
52static constexpr uint8_t kOpNewMethod = 1U;
53static constexpr uint8_t kOpNewThread = 2U;
54
55class BuildStackTraceVisitor : public StackVisitor {
56 public:
57  explicit BuildStackTraceVisitor(Thread* thread)
58      : StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames),
59        method_trace_(Trace::AllocStackTrace()) {}
60
61  bool VisitFrame() SHARED_REQUIRES(Locks::mutator_lock_) {
62    ArtMethod* m = GetMethod();
63    // Ignore runtime frames (in particular callee save).
64    if (!m->IsRuntimeMethod()) {
65      method_trace_->push_back(m);
66    }
67    return true;
68  }
69
70  // Returns a stack trace where the topmost frame corresponds with the first element of the vector.
71  std::vector<ArtMethod*>* GetStackTrace() const {
72    return method_trace_;
73  }
74
75 private:
76  std::vector<ArtMethod*>* const method_trace_;
77
78  DISALLOW_COPY_AND_ASSIGN(BuildStackTraceVisitor);
79};
80
81static const char     kTraceTokenChar             = '*';
82static const uint16_t kTraceHeaderLength          = 32;
83static const uint32_t kTraceMagicValue            = 0x574f4c53;
84static const uint16_t kTraceVersionSingleClock    = 2;
85static const uint16_t kTraceVersionDualClock      = 3;
86static const uint16_t kTraceRecordSizeSingleClock = 10;  // using v2
87static const uint16_t kTraceRecordSizeDualClock   = 14;  // using v3 with two timestamps
88
89TraceClockSource Trace::default_clock_source_ = kDefaultTraceClockSource;
90
91Trace* volatile Trace::the_trace_ = nullptr;
92pthread_t Trace::sampling_pthread_ = 0U;
93std::unique_ptr<std::vector<ArtMethod*>> Trace::temp_stack_trace_;
94
95// The key identifying the tracer to update instrumentation.
96static constexpr const char* kTracerInstrumentationKey = "Tracer";
97
98static TraceAction DecodeTraceAction(uint32_t tmid) {
99  return static_cast<TraceAction>(tmid & kTraceMethodActionMask);
100}
101
102ArtMethod* Trace::DecodeTraceMethod(uint32_t tmid) {
103  MutexLock mu(Thread::Current(), *unique_methods_lock_);
104  return unique_methods_[tmid >> TraceActionBits];
105}
106
107uint32_t Trace::EncodeTraceMethod(ArtMethod* method) {
108  MutexLock mu(Thread::Current(), *unique_methods_lock_);
109  uint32_t idx;
110  auto it = art_method_id_map_.find(method);
111  if (it != art_method_id_map_.end()) {
112    idx = it->second;
113  } else {
114    unique_methods_.push_back(method);
115    idx = unique_methods_.size() - 1;
116    art_method_id_map_.emplace(method, idx);
117  }
118  DCHECK_LT(idx, unique_methods_.size());
119  DCHECK_EQ(unique_methods_[idx], method);
120  return idx;
121}
122
123uint32_t Trace::EncodeTraceMethodAndAction(ArtMethod* method, TraceAction action) {
124  uint32_t tmid = (EncodeTraceMethod(method) << TraceActionBits) | action;
125  DCHECK_EQ(method, DecodeTraceMethod(tmid));
126  return tmid;
127}
128
129std::vector<ArtMethod*>* Trace::AllocStackTrace() {
130  return (temp_stack_trace_.get() != nullptr)  ? temp_stack_trace_.release() :
131      new std::vector<ArtMethod*>();
132}
133
134void Trace::FreeStackTrace(std::vector<ArtMethod*>* stack_trace) {
135  stack_trace->clear();
136  temp_stack_trace_.reset(stack_trace);
137}
138
139void Trace::SetDefaultClockSource(TraceClockSource clock_source) {
140#if defined(__linux__)
141  default_clock_source_ = clock_source;
142#else
143  if (clock_source != TraceClockSource::kWall) {
144    LOG(WARNING) << "Ignoring tracing request to use CPU time.";
145  }
146#endif
147}
148
149static uint16_t GetTraceVersion(TraceClockSource clock_source) {
150  return (clock_source == TraceClockSource::kDual) ? kTraceVersionDualClock
151                                                    : kTraceVersionSingleClock;
152}
153
154static uint16_t GetRecordSize(TraceClockSource clock_source) {
155  return (clock_source == TraceClockSource::kDual) ? kTraceRecordSizeDualClock
156                                                    : kTraceRecordSizeSingleClock;
157}
158
159bool Trace::UseThreadCpuClock() {
160  return (clock_source_ == TraceClockSource::kThreadCpu) ||
161      (clock_source_ == TraceClockSource::kDual);
162}
163
164bool Trace::UseWallClock() {
165  return (clock_source_ == TraceClockSource::kWall) ||
166      (clock_source_ == TraceClockSource::kDual);
167}
168
169void Trace::MeasureClockOverhead() {
170  if (UseThreadCpuClock()) {
171    Thread::Current()->GetCpuMicroTime();
172  }
173  if (UseWallClock()) {
174    MicroTime();
175  }
176}
177
178// Compute an average time taken to measure clocks.
179uint32_t Trace::GetClockOverheadNanoSeconds() {
180  Thread* self = Thread::Current();
181  uint64_t start = self->GetCpuMicroTime();
182
183  for (int i = 4000; i > 0; i--) {
184    MeasureClockOverhead();
185    MeasureClockOverhead();
186    MeasureClockOverhead();
187    MeasureClockOverhead();
188    MeasureClockOverhead();
189    MeasureClockOverhead();
190    MeasureClockOverhead();
191    MeasureClockOverhead();
192  }
193
194  uint64_t elapsed_us = self->GetCpuMicroTime() - start;
195  return static_cast<uint32_t>(elapsed_us / 32);
196}
197
198// TODO: put this somewhere with the big-endian equivalent used by JDWP.
199static void Append2LE(uint8_t* buf, uint16_t val) {
200  *buf++ = static_cast<uint8_t>(val);
201  *buf++ = static_cast<uint8_t>(val >> 8);
202}
203
204// TODO: put this somewhere with the big-endian equivalent used by JDWP.
205static void Append4LE(uint8_t* buf, uint32_t val) {
206  *buf++ = static_cast<uint8_t>(val);
207  *buf++ = static_cast<uint8_t>(val >> 8);
208  *buf++ = static_cast<uint8_t>(val >> 16);
209  *buf++ = static_cast<uint8_t>(val >> 24);
210}
211
212// TODO: put this somewhere with the big-endian equivalent used by JDWP.
213static void Append8LE(uint8_t* buf, uint64_t val) {
214  *buf++ = static_cast<uint8_t>(val);
215  *buf++ = static_cast<uint8_t>(val >> 8);
216  *buf++ = static_cast<uint8_t>(val >> 16);
217  *buf++ = static_cast<uint8_t>(val >> 24);
218  *buf++ = static_cast<uint8_t>(val >> 32);
219  *buf++ = static_cast<uint8_t>(val >> 40);
220  *buf++ = static_cast<uint8_t>(val >> 48);
221  *buf++ = static_cast<uint8_t>(val >> 56);
222}
223
224static void GetSample(Thread* thread, void* arg) SHARED_REQUIRES(Locks::mutator_lock_) {
225  BuildStackTraceVisitor build_trace_visitor(thread);
226  build_trace_visitor.WalkStack();
227  std::vector<ArtMethod*>* stack_trace = build_trace_visitor.GetStackTrace();
228  Trace* the_trace = reinterpret_cast<Trace*>(arg);
229  the_trace->CompareAndUpdateStackTrace(thread, stack_trace);
230}
231
232static void ClearThreadStackTraceAndClockBase(Thread* thread, void* arg ATTRIBUTE_UNUSED) {
233  thread->SetTraceClockBase(0);
234  std::vector<ArtMethod*>* stack_trace = thread->GetStackTraceSample();
235  thread->SetStackTraceSample(nullptr);
236  delete stack_trace;
237}
238
239void Trace::CompareAndUpdateStackTrace(Thread* thread,
240                                       std::vector<ArtMethod*>* stack_trace) {
241  CHECK_EQ(pthread_self(), sampling_pthread_);
242  std::vector<ArtMethod*>* old_stack_trace = thread->GetStackTraceSample();
243  // Update the thread's stack trace sample.
244  thread->SetStackTraceSample(stack_trace);
245  // Read timer clocks to use for all events in this trace.
246  uint32_t thread_clock_diff = 0;
247  uint32_t wall_clock_diff = 0;
248  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
249  if (old_stack_trace == nullptr) {
250    // If there's no previous stack trace sample for this thread, log an entry event for all
251    // methods in the trace.
252    for (auto rit = stack_trace->rbegin(); rit != stack_trace->rend(); ++rit) {
253      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
254                          thread_clock_diff, wall_clock_diff);
255    }
256  } else {
257    // If there's a previous stack trace for this thread, diff the traces and emit entry and exit
258    // events accordingly.
259    auto old_rit = old_stack_trace->rbegin();
260    auto rit = stack_trace->rbegin();
261    // Iterate bottom-up over both traces until there's a difference between them.
262    while (old_rit != old_stack_trace->rend() && rit != stack_trace->rend() && *old_rit == *rit) {
263      old_rit++;
264      rit++;
265    }
266    // Iterate top-down over the old trace until the point where they differ, emitting exit events.
267    for (auto old_it = old_stack_trace->begin(); old_it != old_rit.base(); ++old_it) {
268      LogMethodTraceEvent(thread, *old_it, instrumentation::Instrumentation::kMethodExited,
269                          thread_clock_diff, wall_clock_diff);
270    }
271    // Iterate bottom-up over the new trace from the point where they differ, emitting entry events.
272    for (; rit != stack_trace->rend(); ++rit) {
273      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
274                          thread_clock_diff, wall_clock_diff);
275    }
276    FreeStackTrace(old_stack_trace);
277  }
278}
279
280void* Trace::RunSamplingThread(void* arg) {
281  Runtime* runtime = Runtime::Current();
282  intptr_t interval_us = reinterpret_cast<intptr_t>(arg);
283  CHECK_GE(interval_us, 0);
284  CHECK(runtime->AttachCurrentThread("Sampling Profiler", true, runtime->GetSystemThreadGroup(),
285                                     !runtime->IsAotCompiler()));
286
287  while (true) {
288    usleep(interval_us);
289    ATRACE_BEGIN("Profile sampling");
290    Thread* self = Thread::Current();
291    Trace* the_trace;
292    {
293      MutexLock mu(self, *Locks::trace_lock_);
294      the_trace = the_trace_;
295      if (the_trace == nullptr) {
296        break;
297      }
298    }
299    {
300      ScopedSuspendAll ssa(__FUNCTION__);
301      MutexLock mu(self, *Locks::thread_list_lock_);
302      runtime->GetThreadList()->ForEach(GetSample, the_trace);
303    }
304    ATRACE_END();
305  }
306
307  runtime->DetachCurrentThread();
308  return nullptr;
309}
310
311void Trace::Start(const char* trace_filename, int trace_fd, size_t buffer_size, int flags,
312                  TraceOutputMode output_mode, TraceMode trace_mode, int interval_us) {
313  Thread* self = Thread::Current();
314  {
315    MutexLock mu(self, *Locks::trace_lock_);
316    if (the_trace_ != nullptr) {
317      LOG(ERROR) << "Trace already in progress, ignoring this request";
318      return;
319    }
320  }
321
322  // Check interval if sampling is enabled
323  if (trace_mode == TraceMode::kSampling && interval_us <= 0) {
324    LOG(ERROR) << "Invalid sampling interval: " << interval_us;
325    ScopedObjectAccess soa(self);
326    ThrowRuntimeException("Invalid sampling interval: %d", interval_us);
327    return;
328  }
329
330  // Open trace file if not going directly to ddms.
331  std::unique_ptr<File> trace_file;
332  if (output_mode != TraceOutputMode::kDDMS) {
333    if (trace_fd < 0) {
334      trace_file.reset(OS::CreateEmptyFileWriteOnly(trace_filename));
335    } else {
336      trace_file.reset(new File(trace_fd, "tracefile"));
337      trace_file->DisableAutoClose();
338    }
339    if (trace_file.get() == nullptr) {
340      PLOG(ERROR) << "Unable to open trace file '" << trace_filename << "'";
341      ScopedObjectAccess soa(self);
342      ThrowRuntimeException("Unable to open trace file '%s'", trace_filename);
343      return;
344    }
345  }
346
347  Runtime* runtime = Runtime::Current();
348
349  // Enable count of allocs if specified in the flags.
350  bool enable_stats = false;
351
352  // Create Trace object.
353  {
354    // Required since EnableMethodTracing calls ConfigureStubs which visits class linker classes.
355    gc::ScopedGCCriticalSection gcs(self,
356                                    gc::kGcCauseInstrumentation,
357                                    gc::kCollectorTypeInstrumentation);
358    ScopedSuspendAll ssa(__FUNCTION__);
359    MutexLock mu(self, *Locks::trace_lock_);
360    if (the_trace_ != nullptr) {
361      LOG(ERROR) << "Trace already in progress, ignoring this request";
362    } else {
363      enable_stats = (flags && kTraceCountAllocs) != 0;
364      the_trace_ = new Trace(trace_file.release(), trace_filename, buffer_size, flags, output_mode,
365                             trace_mode);
366      if (trace_mode == TraceMode::kSampling) {
367        CHECK_PTHREAD_CALL(pthread_create, (&sampling_pthread_, nullptr, &RunSamplingThread,
368                                            reinterpret_cast<void*>(interval_us)),
369                                            "Sampling profiler thread");
370        the_trace_->interval_us_ = interval_us;
371      } else {
372        runtime->GetInstrumentation()->AddListener(the_trace_,
373                                                   instrumentation::Instrumentation::kMethodEntered |
374                                                   instrumentation::Instrumentation::kMethodExited |
375                                                   instrumentation::Instrumentation::kMethodUnwind);
376        // TODO: In full-PIC mode, we don't need to fully deopt.
377        runtime->GetInstrumentation()->EnableMethodTracing(kTracerInstrumentationKey);
378      }
379    }
380  }
381
382  // Can't call this when holding the mutator lock.
383  if (enable_stats) {
384    runtime->SetStatsEnabled(true);
385  }
386}
387
388void Trace::StopTracing(bool finish_tracing, bool flush_file) {
389  bool stop_alloc_counting = false;
390  Runtime* const runtime = Runtime::Current();
391  Trace* the_trace = nullptr;
392  pthread_t sampling_pthread = 0U;
393  {
394    MutexLock mu(Thread::Current(), *Locks::trace_lock_);
395    if (the_trace_ == nullptr) {
396      LOG(ERROR) << "Trace stop requested, but no trace currently running";
397    } else {
398      the_trace = the_trace_;
399      the_trace_ = nullptr;
400      sampling_pthread = sampling_pthread_;
401    }
402  }
403  // Make sure that we join before we delete the trace since we don't want to have
404  // the sampling thread access a stale pointer. This finishes since the sampling thread exits when
405  // the_trace_ is null.
406  if (sampling_pthread != 0U) {
407    CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, nullptr), "sampling thread shutdown");
408    sampling_pthread_ = 0U;
409  }
410
411  {
412    ScopedSuspendAll ssa(__FUNCTION__);
413    if (the_trace != nullptr) {
414      stop_alloc_counting = (the_trace->flags_ & Trace::kTraceCountAllocs) != 0;
415      if (finish_tracing) {
416        the_trace->FinishTracing();
417      }
418
419      if (the_trace->trace_mode_ == TraceMode::kSampling) {
420        MutexLock mu(Thread::Current(), *Locks::thread_list_lock_);
421        runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, nullptr);
422      } else {
423        runtime->GetInstrumentation()->DisableMethodTracing(kTracerInstrumentationKey);
424        runtime->GetInstrumentation()->RemoveListener(
425            the_trace, instrumentation::Instrumentation::kMethodEntered |
426            instrumentation::Instrumentation::kMethodExited |
427            instrumentation::Instrumentation::kMethodUnwind);
428      }
429      if (the_trace->trace_file_.get() != nullptr) {
430        // Do not try to erase, so flush and close explicitly.
431        if (flush_file) {
432          if (the_trace->trace_file_->Flush() != 0) {
433            PLOG(WARNING) << "Could not flush trace file.";
434          }
435        } else {
436          the_trace->trace_file_->MarkUnchecked();  // Do not trigger guard.
437        }
438        if (the_trace->trace_file_->Close() != 0) {
439          PLOG(ERROR) << "Could not close trace file.";
440        }
441      }
442      delete the_trace;
443    }
444  }
445  if (stop_alloc_counting) {
446    // Can be racy since SetStatsEnabled is not guarded by any locks.
447    runtime->SetStatsEnabled(false);
448  }
449}
450
451void Trace::Abort() {
452  // Do not write anything anymore.
453  StopTracing(false, false);
454}
455
456void Trace::Stop() {
457  // Finish writing.
458  StopTracing(true, true);
459}
460
461void Trace::Shutdown() {
462  if (GetMethodTracingMode() != kTracingInactive) {
463    Stop();
464  }
465}
466
467void Trace::Pause() {
468  bool stop_alloc_counting = false;
469  Runtime* runtime = Runtime::Current();
470  Trace* the_trace = nullptr;
471
472  Thread* const self = Thread::Current();
473  pthread_t sampling_pthread = 0U;
474  {
475    MutexLock mu(self, *Locks::trace_lock_);
476    if (the_trace_ == nullptr) {
477      LOG(ERROR) << "Trace pause requested, but no trace currently running";
478      return;
479    } else {
480      the_trace = the_trace_;
481      sampling_pthread = sampling_pthread_;
482    }
483  }
484
485  if (sampling_pthread != 0U) {
486    {
487      MutexLock mu(self, *Locks::trace_lock_);
488      the_trace_ = nullptr;
489    }
490    CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, nullptr), "sampling thread shutdown");
491    sampling_pthread_ = 0U;
492    {
493      MutexLock mu(self, *Locks::trace_lock_);
494      the_trace_ = the_trace;
495    }
496  }
497
498  if (the_trace != nullptr) {
499    gc::ScopedGCCriticalSection gcs(self,
500                                    gc::kGcCauseInstrumentation,
501                                    gc::kCollectorTypeInstrumentation);
502    ScopedSuspendAll ssa(__FUNCTION__);
503    stop_alloc_counting = (the_trace->flags_ & Trace::kTraceCountAllocs) != 0;
504
505    if (the_trace->trace_mode_ == TraceMode::kSampling) {
506      MutexLock mu(self, *Locks::thread_list_lock_);
507      runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, nullptr);
508    } else {
509      runtime->GetInstrumentation()->DisableMethodTracing(kTracerInstrumentationKey);
510      runtime->GetInstrumentation()->RemoveListener(
511          the_trace,
512          instrumentation::Instrumentation::kMethodEntered |
513          instrumentation::Instrumentation::kMethodExited |
514          instrumentation::Instrumentation::kMethodUnwind);
515    }
516  }
517
518  if (stop_alloc_counting) {
519    // Can be racy since SetStatsEnabled is not guarded by any locks.
520    Runtime::Current()->SetStatsEnabled(false);
521  }
522}
523
524void Trace::Resume() {
525  Thread* self = Thread::Current();
526  Trace* the_trace;
527  {
528    MutexLock mu(self, *Locks::trace_lock_);
529    if (the_trace_ == nullptr) {
530      LOG(ERROR) << "No trace to resume (or sampling mode), ignoring this request";
531      return;
532    }
533    the_trace = the_trace_;
534  }
535
536  Runtime* runtime = Runtime::Current();
537
538  // Enable count of allocs if specified in the flags.
539  bool enable_stats = (the_trace->flags_ && kTraceCountAllocs) != 0;
540
541  {
542    gc::ScopedGCCriticalSection gcs(self,
543                                    gc::kGcCauseInstrumentation,
544                                    gc::kCollectorTypeInstrumentation);
545    ScopedSuspendAll ssa(__FUNCTION__);
546
547    // Reenable.
548    if (the_trace->trace_mode_ == TraceMode::kSampling) {
549      CHECK_PTHREAD_CALL(pthread_create, (&sampling_pthread_, nullptr, &RunSamplingThread,
550          reinterpret_cast<void*>(the_trace->interval_us_)), "Sampling profiler thread");
551    } else {
552      runtime->GetInstrumentation()->AddListener(the_trace,
553                                                 instrumentation::Instrumentation::kMethodEntered |
554                                                 instrumentation::Instrumentation::kMethodExited |
555                                                 instrumentation::Instrumentation::kMethodUnwind);
556      // TODO: In full-PIC mode, we don't need to fully deopt.
557      runtime->GetInstrumentation()->EnableMethodTracing(kTracerInstrumentationKey);
558    }
559  }
560
561  // Can't call this when holding the mutator lock.
562  if (enable_stats) {
563    runtime->SetStatsEnabled(true);
564  }
565}
566
567TracingMode Trace::GetMethodTracingMode() {
568  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
569  if (the_trace_ == nullptr) {
570    return kTracingInactive;
571  } else {
572    switch (the_trace_->trace_mode_) {
573      case TraceMode::kSampling:
574        return kSampleProfilingActive;
575      case TraceMode::kMethodTracing:
576        return kMethodTracingActive;
577    }
578    LOG(FATAL) << "Unreachable";
579    UNREACHABLE();
580  }
581}
582
583static constexpr size_t kMinBufSize = 18U;  // Trace header is up to 18B.
584
585Trace::Trace(File* trace_file, const char* trace_name, size_t buffer_size, int flags,
586             TraceOutputMode output_mode, TraceMode trace_mode)
587    : trace_file_(trace_file),
588      buf_(new uint8_t[std::max(kMinBufSize, buffer_size)]()),
589      flags_(flags), trace_output_mode_(output_mode), trace_mode_(trace_mode),
590      clock_source_(default_clock_source_),
591      buffer_size_(std::max(kMinBufSize, buffer_size)),
592      start_time_(MicroTime()), clock_overhead_ns_(GetClockOverheadNanoSeconds()), cur_offset_(0),
593      overflow_(false), interval_us_(0), streaming_lock_(nullptr),
594      unique_methods_lock_(new Mutex("unique methods lock", kTracingUniqueMethodsLock)) {
595  uint16_t trace_version = GetTraceVersion(clock_source_);
596  if (output_mode == TraceOutputMode::kStreaming) {
597    trace_version |= 0xF0U;
598  }
599  // Set up the beginning of the trace.
600  memset(buf_.get(), 0, kTraceHeaderLength);
601  Append4LE(buf_.get(), kTraceMagicValue);
602  Append2LE(buf_.get() + 4, trace_version);
603  Append2LE(buf_.get() + 6, kTraceHeaderLength);
604  Append8LE(buf_.get() + 8, start_time_);
605  if (trace_version >= kTraceVersionDualClock) {
606    uint16_t record_size = GetRecordSize(clock_source_);
607    Append2LE(buf_.get() + 16, record_size);
608  }
609  static_assert(18 <= kMinBufSize, "Minimum buffer size not large enough for trace header");
610
611  // Update current offset.
612  cur_offset_.StoreRelaxed(kTraceHeaderLength);
613
614  if (output_mode == TraceOutputMode::kStreaming) {
615    streaming_file_name_ = trace_name;
616    streaming_lock_ = new Mutex("tracing lock", LockLevel::kTracingStreamingLock);
617    seen_threads_.reset(new ThreadIDBitSet());
618  }
619}
620
621Trace::~Trace() {
622  delete streaming_lock_;
623  delete unique_methods_lock_;
624}
625
626static uint64_t ReadBytes(uint8_t* buf, size_t bytes) {
627  uint64_t ret = 0;
628  for (size_t i = 0; i < bytes; ++i) {
629    ret |= static_cast<uint64_t>(buf[i]) << (i * 8);
630  }
631  return ret;
632}
633
634void Trace::DumpBuf(uint8_t* buf, size_t buf_size, TraceClockSource clock_source) {
635  uint8_t* ptr = buf + kTraceHeaderLength;
636  uint8_t* end = buf + buf_size;
637
638  while (ptr < end) {
639    uint32_t tmid = ReadBytes(ptr + 2, sizeof(tmid));
640    ArtMethod* method = DecodeTraceMethod(tmid);
641    TraceAction action = DecodeTraceAction(tmid);
642    LOG(INFO) << PrettyMethod(method) << " " << static_cast<int>(action);
643    ptr += GetRecordSize(clock_source);
644  }
645}
646
647static void GetVisitedMethodsFromBitSets(
648    const std::map<const DexFile*, DexIndexBitSet*>& seen_methods,
649    std::set<ArtMethod*>* visited_methods) SHARED_REQUIRES(Locks::mutator_lock_) {
650  ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
651  Thread* const self = Thread::Current();
652  for (auto& e : seen_methods) {
653    DexIndexBitSet* bit_set = e.second;
654    // TODO: Visit trace methods as roots.
655    mirror::DexCache* dex_cache = class_linker->FindDexCache(self, *e.first, false);
656    for (uint32_t i = 0; i < bit_set->size(); ++i) {
657      if ((*bit_set)[i]) {
658        visited_methods->insert(dex_cache->GetResolvedMethod(i, sizeof(void*)));
659      }
660    }
661  }
662}
663
664void Trace::FinishTracing() {
665  size_t final_offset = 0;
666
667  std::set<ArtMethod*> visited_methods;
668  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
669    // Write the secondary file with all the method names.
670    GetVisitedMethodsFromBitSets(seen_methods_, &visited_methods);
671
672    // Clean up.
673    STLDeleteValues(&seen_methods_);
674  } else {
675    final_offset = cur_offset_.LoadRelaxed();
676    GetVisitedMethods(final_offset, &visited_methods);
677  }
678
679  // Compute elapsed time.
680  uint64_t elapsed = MicroTime() - start_time_;
681
682  std::ostringstream os;
683
684  os << StringPrintf("%cversion\n", kTraceTokenChar);
685  os << StringPrintf("%d\n", GetTraceVersion(clock_source_));
686  os << StringPrintf("data-file-overflow=%s\n", overflow_ ? "true" : "false");
687  if (UseThreadCpuClock()) {
688    if (UseWallClock()) {
689      os << StringPrintf("clock=dual\n");
690    } else {
691      os << StringPrintf("clock=thread-cpu\n");
692    }
693  } else {
694    os << StringPrintf("clock=wall\n");
695  }
696  os << StringPrintf("elapsed-time-usec=%" PRIu64 "\n", elapsed);
697  if (trace_output_mode_ != TraceOutputMode::kStreaming) {
698    size_t num_records = (final_offset - kTraceHeaderLength) / GetRecordSize(clock_source_);
699    os << StringPrintf("num-method-calls=%zd\n", num_records);
700  }
701  os << StringPrintf("clock-call-overhead-nsec=%d\n", clock_overhead_ns_);
702  os << StringPrintf("vm=art\n");
703  os << StringPrintf("pid=%d\n", getpid());
704  if ((flags_ & kTraceCountAllocs) != 0) {
705    os << StringPrintf("alloc-count=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_OBJECTS));
706    os << StringPrintf("alloc-size=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_BYTES));
707    os << StringPrintf("gc-count=%d\n", Runtime::Current()->GetStat(KIND_GC_INVOCATIONS));
708  }
709  os << StringPrintf("%cthreads\n", kTraceTokenChar);
710  DumpThreadList(os);
711  os << StringPrintf("%cmethods\n", kTraceTokenChar);
712  DumpMethodList(os, visited_methods);
713  os << StringPrintf("%cend\n", kTraceTokenChar);
714  std::string header(os.str());
715
716  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
717    File file;
718    if (!file.Open(streaming_file_name_ + ".sec", O_CREAT | O_WRONLY)) {
719      LOG(WARNING) << "Could not open secondary trace file!";
720      return;
721    }
722    if (!file.WriteFully(header.c_str(), header.length())) {
723      file.Erase();
724      std::string detail(StringPrintf("Trace data write failed: %s", strerror(errno)));
725      PLOG(ERROR) << detail;
726      ThrowRuntimeException("%s", detail.c_str());
727    }
728    if (file.FlushCloseOrErase() != 0) {
729      PLOG(ERROR) << "Could not write secondary file";
730    }
731  } else {
732    if (trace_file_.get() == nullptr) {
733      iovec iov[2];
734      iov[0].iov_base = reinterpret_cast<void*>(const_cast<char*>(header.c_str()));
735      iov[0].iov_len = header.length();
736      iov[1].iov_base = buf_.get();
737      iov[1].iov_len = final_offset;
738      Dbg::DdmSendChunkV(CHUNK_TYPE("MPSE"), iov, 2);
739      const bool kDumpTraceInfo = false;
740      if (kDumpTraceInfo) {
741        LOG(INFO) << "Trace sent:\n" << header;
742        DumpBuf(buf_.get(), final_offset, clock_source_);
743      }
744    } else {
745      if (!trace_file_->WriteFully(header.c_str(), header.length()) ||
746          !trace_file_->WriteFully(buf_.get(), final_offset)) {
747        std::string detail(StringPrintf("Trace data write failed: %s", strerror(errno)));
748        PLOG(ERROR) << detail;
749        ThrowRuntimeException("%s", detail.c_str());
750      }
751    }
752  }
753}
754
755void Trace::DexPcMoved(Thread* thread ATTRIBUTE_UNUSED,
756                       mirror::Object* this_object ATTRIBUTE_UNUSED,
757                       ArtMethod* method,
758                       uint32_t new_dex_pc) {
759  // We're not recorded to listen to this kind of event, so complain.
760  LOG(ERROR) << "Unexpected dex PC event in tracing " << PrettyMethod(method) << " " << new_dex_pc;
761}
762
763void Trace::FieldRead(Thread* thread ATTRIBUTE_UNUSED,
764                      mirror::Object* this_object ATTRIBUTE_UNUSED,
765                      ArtMethod* method,
766                      uint32_t dex_pc,
767                      ArtField* field ATTRIBUTE_UNUSED)
768    SHARED_REQUIRES(Locks::mutator_lock_) {
769  // We're not recorded to listen to this kind of event, so complain.
770  LOG(ERROR) << "Unexpected field read event in tracing " << PrettyMethod(method) << " " << dex_pc;
771}
772
773void Trace::FieldWritten(Thread* thread ATTRIBUTE_UNUSED,
774                         mirror::Object* this_object ATTRIBUTE_UNUSED,
775                         ArtMethod* method,
776                         uint32_t dex_pc,
777                         ArtField* field ATTRIBUTE_UNUSED,
778                         const JValue& field_value ATTRIBUTE_UNUSED)
779    SHARED_REQUIRES(Locks::mutator_lock_) {
780  // We're not recorded to listen to this kind of event, so complain.
781  LOG(ERROR) << "Unexpected field write event in tracing " << PrettyMethod(method) << " " << dex_pc;
782}
783
784void Trace::MethodEntered(Thread* thread, mirror::Object* this_object ATTRIBUTE_UNUSED,
785                          ArtMethod* method, uint32_t dex_pc ATTRIBUTE_UNUSED) {
786  uint32_t thread_clock_diff = 0;
787  uint32_t wall_clock_diff = 0;
788  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
789  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodEntered,
790                      thread_clock_diff, wall_clock_diff);
791}
792
793void Trace::MethodExited(Thread* thread, mirror::Object* this_object ATTRIBUTE_UNUSED,
794                         ArtMethod* method, uint32_t dex_pc ATTRIBUTE_UNUSED,
795                         const JValue& return_value ATTRIBUTE_UNUSED) {
796  uint32_t thread_clock_diff = 0;
797  uint32_t wall_clock_diff = 0;
798  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
799  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodExited,
800                      thread_clock_diff, wall_clock_diff);
801}
802
803void Trace::MethodUnwind(Thread* thread, mirror::Object* this_object ATTRIBUTE_UNUSED,
804                         ArtMethod* method, uint32_t dex_pc ATTRIBUTE_UNUSED) {
805  uint32_t thread_clock_diff = 0;
806  uint32_t wall_clock_diff = 0;
807  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
808  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodUnwind,
809                      thread_clock_diff, wall_clock_diff);
810}
811
812void Trace::ExceptionCaught(Thread* thread ATTRIBUTE_UNUSED,
813                            mirror::Throwable* exception_object ATTRIBUTE_UNUSED)
814    SHARED_REQUIRES(Locks::mutator_lock_) {
815  LOG(ERROR) << "Unexpected exception caught event in tracing";
816}
817
818void Trace::BackwardBranch(Thread* /*thread*/, ArtMethod* method,
819                           int32_t /*dex_pc_offset*/)
820      SHARED_REQUIRES(Locks::mutator_lock_) {
821  LOG(ERROR) << "Unexpected backward branch event in tracing" << PrettyMethod(method);
822}
823
824void Trace::InvokeVirtualOrInterface(Thread*,
825                                     mirror::Object*,
826                                     ArtMethod* method,
827                                     uint32_t dex_pc,
828                                     ArtMethod*) {
829  LOG(ERROR) << "Unexpected invoke event in tracing" << PrettyMethod(method)
830             << " " << dex_pc;
831}
832
833void Trace::ReadClocks(Thread* thread, uint32_t* thread_clock_diff, uint32_t* wall_clock_diff) {
834  if (UseThreadCpuClock()) {
835    uint64_t clock_base = thread->GetTraceClockBase();
836    if (UNLIKELY(clock_base == 0)) {
837      // First event, record the base time in the map.
838      uint64_t time = thread->GetCpuMicroTime();
839      thread->SetTraceClockBase(time);
840    } else {
841      *thread_clock_diff = thread->GetCpuMicroTime() - clock_base;
842    }
843  }
844  if (UseWallClock()) {
845    *wall_clock_diff = MicroTime() - start_time_;
846  }
847}
848
849bool Trace::RegisterMethod(ArtMethod* method) {
850  mirror::DexCache* dex_cache = method->GetDexCache();
851  const DexFile* dex_file = dex_cache->GetDexFile();
852  auto* resolved_method = dex_cache->GetResolvedMethod(method->GetDexMethodIndex(), sizeof(void*));
853  if (resolved_method != method) {
854    DCHECK(resolved_method == nullptr);
855    dex_cache->SetResolvedMethod(method->GetDexMethodIndex(), method, sizeof(void*));
856  }
857  if (seen_methods_.find(dex_file) == seen_methods_.end()) {
858    seen_methods_.insert(std::make_pair(dex_file, new DexIndexBitSet()));
859  }
860  DexIndexBitSet* bit_set = seen_methods_.find(dex_file)->second;
861  if (!(*bit_set)[method->GetDexMethodIndex()]) {
862    bit_set->set(method->GetDexMethodIndex());
863    return true;
864  }
865  return false;
866}
867
868bool Trace::RegisterThread(Thread* thread) {
869  pid_t tid = thread->GetTid();
870  CHECK_LT(0U, static_cast<uint32_t>(tid));
871  CHECK_LT(static_cast<uint32_t>(tid), 65536U);
872
873  if (!(*seen_threads_)[tid]) {
874    seen_threads_->set(tid);
875    return true;
876  }
877  return false;
878}
879
880std::string Trace::GetMethodLine(ArtMethod* method) {
881  method = method->GetInterfaceMethodIfProxy(sizeof(void*));
882  return StringPrintf("%p\t%s\t%s\t%s\t%s\n",
883                      reinterpret_cast<void*>((EncodeTraceMethod(method) << TraceActionBits)),
884      PrettyDescriptor(method->GetDeclaringClassDescriptor()).c_str(), method->GetName(),
885      method->GetSignature().ToString().c_str(), method->GetDeclaringClassSourceFile());
886}
887
888void Trace::WriteToBuf(const uint8_t* src, size_t src_size) {
889  int32_t old_offset = cur_offset_.LoadRelaxed();
890  int32_t new_offset = old_offset + static_cast<int32_t>(src_size);
891  if (dchecked_integral_cast<size_t>(new_offset) > buffer_size_) {
892    // Flush buffer.
893    if (!trace_file_->WriteFully(buf_.get(), old_offset)) {
894      PLOG(WARNING) << "Failed streaming a tracing event.";
895    }
896
897    // Check whether the data is too large for the buffer, then write immediately.
898    if (src_size >= buffer_size_) {
899      if (!trace_file_->WriteFully(src, src_size)) {
900        PLOG(WARNING) << "Failed streaming a tracing event.";
901      }
902      cur_offset_.StoreRelease(0);  // Buffer is empty now.
903      return;
904    }
905
906    old_offset = 0;
907    new_offset = static_cast<int32_t>(src_size);
908  }
909  cur_offset_.StoreRelease(new_offset);
910  // Fill in data.
911  memcpy(buf_.get() + old_offset, src, src_size);
912}
913
914void Trace::LogMethodTraceEvent(Thread* thread, ArtMethod* method,
915                                instrumentation::Instrumentation::InstrumentationEvent event,
916                                uint32_t thread_clock_diff, uint32_t wall_clock_diff) {
917  // Advance cur_offset_ atomically.
918  int32_t new_offset;
919  int32_t old_offset = 0;
920
921  // We do a busy loop here trying to acquire the next offset.
922  if (trace_output_mode_ != TraceOutputMode::kStreaming) {
923    do {
924      old_offset = cur_offset_.LoadRelaxed();
925      new_offset = old_offset + GetRecordSize(clock_source_);
926      if (static_cast<size_t>(new_offset) > buffer_size_) {
927        overflow_ = true;
928        return;
929      }
930    } while (!cur_offset_.CompareExchangeWeakSequentiallyConsistent(old_offset, new_offset));
931  }
932
933  TraceAction action = kTraceMethodEnter;
934  switch (event) {
935    case instrumentation::Instrumentation::kMethodEntered:
936      action = kTraceMethodEnter;
937      break;
938    case instrumentation::Instrumentation::kMethodExited:
939      action = kTraceMethodExit;
940      break;
941    case instrumentation::Instrumentation::kMethodUnwind:
942      action = kTraceUnroll;
943      break;
944    default:
945      UNIMPLEMENTED(FATAL) << "Unexpected event: " << event;
946  }
947
948  uint32_t method_value = EncodeTraceMethodAndAction(method, action);
949
950  // Write data
951  uint8_t* ptr;
952  static constexpr size_t kPacketSize = 14U;  // The maximum size of data in a packet.
953  uint8_t stack_buf[kPacketSize];             // Space to store a packet when in streaming mode.
954  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
955    ptr = stack_buf;
956  } else {
957    ptr = buf_.get() + old_offset;
958  }
959
960  Append2LE(ptr, thread->GetTid());
961  Append4LE(ptr + 2, method_value);
962  ptr += 6;
963
964  if (UseThreadCpuClock()) {
965    Append4LE(ptr, thread_clock_diff);
966    ptr += 4;
967  }
968  if (UseWallClock()) {
969    Append4LE(ptr, wall_clock_diff);
970  }
971  static_assert(kPacketSize == 2 + 4 + 4 + 4, "Packet size incorrect.");
972
973  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
974    MutexLock mu(Thread::Current(), *streaming_lock_);  // To serialize writing.
975    if (RegisterMethod(method)) {
976      // Write a special block with the name.
977      std::string method_line(GetMethodLine(method));
978      uint8_t buf2[5];
979      Append2LE(buf2, 0);
980      buf2[2] = kOpNewMethod;
981      Append2LE(buf2 + 3, static_cast<uint16_t>(method_line.length()));
982      WriteToBuf(buf2, sizeof(buf2));
983      WriteToBuf(reinterpret_cast<const uint8_t*>(method_line.c_str()), method_line.length());
984    }
985    if (RegisterThread(thread)) {
986      // It might be better to postpone this. Threads might not have received names...
987      std::string thread_name;
988      thread->GetThreadName(thread_name);
989      uint8_t buf2[7];
990      Append2LE(buf2, 0);
991      buf2[2] = kOpNewThread;
992      Append2LE(buf2 + 3, static_cast<uint16_t>(thread->GetTid()));
993      Append2LE(buf2 + 5, static_cast<uint16_t>(thread_name.length()));
994      WriteToBuf(buf2, sizeof(buf2));
995      WriteToBuf(reinterpret_cast<const uint8_t*>(thread_name.c_str()), thread_name.length());
996    }
997    WriteToBuf(stack_buf, sizeof(stack_buf));
998  }
999}
1000
1001void Trace::GetVisitedMethods(size_t buf_size,
1002                              std::set<ArtMethod*>* visited_methods) {
1003  uint8_t* ptr = buf_.get() + kTraceHeaderLength;
1004  uint8_t* end = buf_.get() + buf_size;
1005
1006  while (ptr < end) {
1007    uint32_t tmid = ReadBytes(ptr + 2, sizeof(tmid));
1008    ArtMethod* method = DecodeTraceMethod(tmid);
1009    visited_methods->insert(method);
1010    ptr += GetRecordSize(clock_source_);
1011  }
1012}
1013
1014void Trace::DumpMethodList(std::ostream& os, const std::set<ArtMethod*>& visited_methods) {
1015  for (const auto& method : visited_methods) {
1016    os << GetMethodLine(method);
1017  }
1018}
1019
1020static void DumpThread(Thread* t, void* arg) {
1021  std::ostream& os = *reinterpret_cast<std::ostream*>(arg);
1022  std::string name;
1023  t->GetThreadName(name);
1024  os << t->GetTid() << "\t" << name << "\n";
1025}
1026
1027void Trace::DumpThreadList(std::ostream& os) {
1028  Thread* self = Thread::Current();
1029  for (auto it : exited_threads_) {
1030    os << it.first << "\t" << it.second << "\n";
1031  }
1032  Locks::thread_list_lock_->AssertNotHeld(self);
1033  MutexLock mu(self, *Locks::thread_list_lock_);
1034  Runtime::Current()->GetThreadList()->ForEach(DumpThread, &os);
1035}
1036
1037void Trace::StoreExitingThreadInfo(Thread* thread) {
1038  MutexLock mu(thread, *Locks::trace_lock_);
1039  if (the_trace_ != nullptr) {
1040    std::string name;
1041    thread->GetThreadName(name);
1042    // The same thread/tid may be used multiple times. As SafeMap::Put does not allow to override
1043    // a previous mapping, use SafeMap::Overwrite.
1044    the_trace_->exited_threads_.Overwrite(thread->GetTid(), name);
1045  }
1046}
1047
1048Trace::TraceOutputMode Trace::GetOutputMode() {
1049  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1050  CHECK(the_trace_ != nullptr) << "Trace output mode requested, but no trace currently running";
1051  return the_trace_->trace_output_mode_;
1052}
1053
1054Trace::TraceMode Trace::GetMode() {
1055  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1056  CHECK(the_trace_ != nullptr) << "Trace mode requested, but no trace currently running";
1057  return the_trace_->trace_mode_;
1058}
1059
1060size_t Trace::GetBufferSize() {
1061  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1062  CHECK(the_trace_ != nullptr) << "Trace mode requested, but no trace currently running";
1063  return the_trace_->buffer_size_;
1064}
1065
1066bool Trace::IsTracingEnabled() {
1067  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1068  return the_trace_ != nullptr;
1069}
1070
1071}  // namespace art
1072