trace.cc revision 81a9087f0df0518c39405b7d18ba5858a6d8b77b 
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 "instrumentation.h"
35#include "mirror/class-inl.h"
36#include "mirror/dex_cache-inl.h"
37#include "mirror/object_array-inl.h"
38#include "mirror/object-inl.h"
39#include "os.h"
40#include "scoped_thread_state_change.h"
41#include "ScopedLocalRef.h"
42#include "thread.h"
43#include "thread_list.h"
44#include "utils.h"
45#include "entrypoints/quick/quick_entrypoints.h"
46
47namespace art {
48
49static constexpr size_t TraceActionBits = MinimumBitsToStore(
50    static_cast<size_t>(kTraceMethodActionMask));
51static constexpr uint8_t kOpNewMethod = 1U;
52static constexpr uint8_t kOpNewThread = 2U;
53
54class BuildStackTraceVisitor : public StackVisitor {
55 public:
56  explicit BuildStackTraceVisitor(Thread* thread)
57      : StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames),
58        method_trace_(Trace::AllocStackTrace()) {}
59
60  bool VisitFrame() SHARED_REQUIRES(Locks::mutator_lock_) {
61    ArtMethod* m = GetMethod();
62    // Ignore runtime frames (in particular callee save).
63    if (!m->IsRuntimeMethod()) {
64      method_trace_->push_back(m);
65    }
66    return true;
67  }
68
69  // Returns a stack trace where the topmost frame corresponds with the first element of the vector.
70  std::vector<ArtMethod*>* GetStackTrace() const {
71    return method_trace_;
72  }
73
74 private:
75  std::vector<ArtMethod*>* const method_trace_;
76};
77
78static const char     kTraceTokenChar             = '*';
79static const uint16_t kTraceHeaderLength          = 32;
80static const uint32_t kTraceMagicValue            = 0x574f4c53;
81static const uint16_t kTraceVersionSingleClock    = 2;
82static const uint16_t kTraceVersionDualClock      = 3;
83static const uint16_t kTraceRecordSizeSingleClock = 10;  // using v2
84static const uint16_t kTraceRecordSizeDualClock   = 14;  // using v3 with two timestamps
85
86TraceClockSource Trace::default_clock_source_ = kDefaultTraceClockSource;
87
88Trace* volatile Trace::the_trace_ = nullptr;
89pthread_t Trace::sampling_pthread_ = 0U;
90std::unique_ptr<std::vector<ArtMethod*>> Trace::temp_stack_trace_;
91
92// The key identifying the tracer to update instrumentation.
93static constexpr const char* kTracerInstrumentationKey = "Tracer";
94
95static TraceAction DecodeTraceAction(uint32_t tmid) {
96  return static_cast<TraceAction>(tmid & kTraceMethodActionMask);
97}
98
99ArtMethod* Trace::DecodeTraceMethod(uint32_t tmid) {
100  MutexLock mu(Thread::Current(), *unique_methods_lock_);
101  return unique_methods_[tmid >> TraceActionBits];
102}
103
104uint32_t Trace::EncodeTraceMethod(ArtMethod* method) {
105  MutexLock mu(Thread::Current(), *unique_methods_lock_);
106  uint32_t idx;
107  auto it = art_method_id_map_.find(method);
108  if (it != art_method_id_map_.end()) {
109    idx = it->second;
110  } else {
111    unique_methods_.push_back(method);
112    idx = unique_methods_.size() - 1;
113    art_method_id_map_.emplace(method, idx);
114  }
115  DCHECK_LT(idx, unique_methods_.size());
116  DCHECK_EQ(unique_methods_[idx], method);
117  return idx;
118}
119
120uint32_t Trace::EncodeTraceMethodAndAction(ArtMethod* method, TraceAction action) {
121  uint32_t tmid = (EncodeTraceMethod(method) << TraceActionBits) | action;
122  DCHECK_EQ(method, DecodeTraceMethod(tmid));
123  return tmid;
124}
125
126std::vector<ArtMethod*>* Trace::AllocStackTrace() {
127  return (temp_stack_trace_.get() != nullptr)  ? temp_stack_trace_.release() :
128      new std::vector<ArtMethod*>();
129}
130
131void Trace::FreeStackTrace(std::vector<ArtMethod*>* stack_trace) {
132  stack_trace->clear();
133  temp_stack_trace_.reset(stack_trace);
134}
135
136void Trace::SetDefaultClockSource(TraceClockSource clock_source) {
137#if defined(__linux__)
138  default_clock_source_ = clock_source;
139#else
140  if (clock_source != TraceClockSource::kWall) {
141    LOG(WARNING) << "Ignoring tracing request to use CPU time.";
142  }
143#endif
144}
145
146static uint16_t GetTraceVersion(TraceClockSource clock_source) {
147  return (clock_source == TraceClockSource::kDual) ? kTraceVersionDualClock
148                                                    : kTraceVersionSingleClock;
149}
150
151static uint16_t GetRecordSize(TraceClockSource clock_source) {
152  return (clock_source == TraceClockSource::kDual) ? kTraceRecordSizeDualClock
153                                                    : kTraceRecordSizeSingleClock;
154}
155
156bool Trace::UseThreadCpuClock() {
157  return (clock_source_ == TraceClockSource::kThreadCpu) ||
158      (clock_source_ == TraceClockSource::kDual);
159}
160
161bool Trace::UseWallClock() {
162  return (clock_source_ == TraceClockSource::kWall) ||
163      (clock_source_ == TraceClockSource::kDual);
164}
165
166void Trace::MeasureClockOverhead() {
167  if (UseThreadCpuClock()) {
168    Thread::Current()->GetCpuMicroTime();
169  }
170  if (UseWallClock()) {
171    MicroTime();
172  }
173}
174
175// Compute an average time taken to measure clocks.
176uint32_t Trace::GetClockOverheadNanoSeconds() {
177  Thread* self = Thread::Current();
178  uint64_t start = self->GetCpuMicroTime();
179
180  for (int i = 4000; i > 0; i--) {
181    MeasureClockOverhead();
182    MeasureClockOverhead();
183    MeasureClockOverhead();
184    MeasureClockOverhead();
185    MeasureClockOverhead();
186    MeasureClockOverhead();
187    MeasureClockOverhead();
188    MeasureClockOverhead();
189  }
190
191  uint64_t elapsed_us = self->GetCpuMicroTime() - start;
192  return static_cast<uint32_t>(elapsed_us / 32);
193}
194
195// TODO: put this somewhere with the big-endian equivalent used by JDWP.
196static void Append2LE(uint8_t* buf, uint16_t val) {
197  *buf++ = static_cast<uint8_t>(val);
198  *buf++ = static_cast<uint8_t>(val >> 8);
199}
200
201// TODO: put this somewhere with the big-endian equivalent used by JDWP.
202static void Append4LE(uint8_t* buf, uint32_t val) {
203  *buf++ = static_cast<uint8_t>(val);
204  *buf++ = static_cast<uint8_t>(val >> 8);
205  *buf++ = static_cast<uint8_t>(val >> 16);
206  *buf++ = static_cast<uint8_t>(val >> 24);
207}
208
209// TODO: put this somewhere with the big-endian equivalent used by JDWP.
210static void Append8LE(uint8_t* buf, uint64_t val) {
211  *buf++ = static_cast<uint8_t>(val);
212  *buf++ = static_cast<uint8_t>(val >> 8);
213  *buf++ = static_cast<uint8_t>(val >> 16);
214  *buf++ = static_cast<uint8_t>(val >> 24);
215  *buf++ = static_cast<uint8_t>(val >> 32);
216  *buf++ = static_cast<uint8_t>(val >> 40);
217  *buf++ = static_cast<uint8_t>(val >> 48);
218  *buf++ = static_cast<uint8_t>(val >> 56);
219}
220
221static void GetSample(Thread* thread, void* arg) SHARED_REQUIRES(Locks::mutator_lock_) {
222  BuildStackTraceVisitor build_trace_visitor(thread);
223  build_trace_visitor.WalkStack();
224  std::vector<ArtMethod*>* stack_trace = build_trace_visitor.GetStackTrace();
225  Trace* the_trace = reinterpret_cast<Trace*>(arg);
226  the_trace->CompareAndUpdateStackTrace(thread, stack_trace);
227}
228
229static void ClearThreadStackTraceAndClockBase(Thread* thread, void* arg ATTRIBUTE_UNUSED) {
230  thread->SetTraceClockBase(0);
231  std::vector<ArtMethod*>* stack_trace = thread->GetStackTraceSample();
232  thread->SetStackTraceSample(nullptr);
233  delete stack_trace;
234}
235
236void Trace::CompareAndUpdateStackTrace(Thread* thread,
237                                       std::vector<ArtMethod*>* stack_trace) {
238  CHECK_EQ(pthread_self(), sampling_pthread_);
239  std::vector<ArtMethod*>* old_stack_trace = thread->GetStackTraceSample();
240  // Update the thread's stack trace sample.
241  thread->SetStackTraceSample(stack_trace);
242  // Read timer clocks to use for all events in this trace.
243  uint32_t thread_clock_diff = 0;
244  uint32_t wall_clock_diff = 0;
245  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
246  if (old_stack_trace == nullptr) {
247    // If there's no previous stack trace sample for this thread, log an entry event for all
248    // methods in the trace.
249    for (auto rit = stack_trace->rbegin(); rit != stack_trace->rend(); ++rit) {
250      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
251                          thread_clock_diff, wall_clock_diff);
252    }
253  } else {
254    // If there's a previous stack trace for this thread, diff the traces and emit entry and exit
255    // events accordingly.
256    auto old_rit = old_stack_trace->rbegin();
257    auto rit = stack_trace->rbegin();
258    // Iterate bottom-up over both traces until there's a difference between them.
259    while (old_rit != old_stack_trace->rend() && rit != stack_trace->rend() && *old_rit == *rit) {
260      old_rit++;
261      rit++;
262    }
263    // Iterate top-down over the old trace until the point where they differ, emitting exit events.
264    for (auto old_it = old_stack_trace->begin(); old_it != old_rit.base(); ++old_it) {
265      LogMethodTraceEvent(thread, *old_it, instrumentation::Instrumentation::kMethodExited,
266                          thread_clock_diff, wall_clock_diff);
267    }
268    // Iterate bottom-up over the new trace from the point where they differ, emitting entry events.
269    for (; rit != stack_trace->rend(); ++rit) {
270      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
271                          thread_clock_diff, wall_clock_diff);
272    }
273    FreeStackTrace(old_stack_trace);
274  }
275}
276
277void* Trace::RunSamplingThread(void* arg) {
278  Runtime* runtime = Runtime::Current();
279  intptr_t interval_us = reinterpret_cast<intptr_t>(arg);
280  CHECK_GE(interval_us, 0);
281  CHECK(runtime->AttachCurrentThread("Sampling Profiler", true, runtime->GetSystemThreadGroup(),
282                                     !runtime->IsAotCompiler()));
283
284  while (true) {
285    usleep(interval_us);
286    ATRACE_BEGIN("Profile sampling");
287    Thread* self = Thread::Current();
288    Trace* the_trace;
289    {
290      MutexLock mu(self, *Locks::trace_lock_);
291      the_trace = the_trace_;
292      if (the_trace == nullptr) {
293        break;
294      }
295    }
296
297    runtime->GetThreadList()->SuspendAll(__FUNCTION__);
298    {
299      MutexLock mu(self, *Locks::thread_list_lock_);
300      runtime->GetThreadList()->ForEach(GetSample, the_trace);
301    }
302    runtime->GetThreadList()->ResumeAll();
303    ATRACE_END();
304  }
305
306  runtime->DetachCurrentThread();
307  return nullptr;
308}
309
310void Trace::Start(const char* trace_filename, int trace_fd, size_t buffer_size, int flags,
311                  TraceOutputMode output_mode, TraceMode trace_mode, int interval_us) {
312  Thread* self = Thread::Current();
313  {
314    MutexLock mu(self, *Locks::trace_lock_);
315    if (the_trace_ != nullptr) {
316      LOG(ERROR) << "Trace already in progress, ignoring this request";
317      return;
318    }
319  }
320
321  // Check interval if sampling is enabled
322  if (trace_mode == TraceMode::kSampling && interval_us <= 0) {
323    LOG(ERROR) << "Invalid sampling interval: " << interval_us;
324    ScopedObjectAccess soa(self);
325    ThrowRuntimeException("Invalid sampling interval: %d", interval_us);
326    return;
327  }
328
329  // Open trace file if not going directly to ddms.
330  std::unique_ptr<File> trace_file;
331  if (output_mode != TraceOutputMode::kDDMS) {
332    if (trace_fd < 0) {
333      trace_file.reset(OS::CreateEmptyFile(trace_filename));
334    } else {
335      trace_file.reset(new File(trace_fd, "tracefile"));
336      trace_file->DisableAutoClose();
337    }
338    if (trace_file.get() == nullptr) {
339      PLOG(ERROR) << "Unable to open trace file '" << trace_filename << "'";
340      ScopedObjectAccess soa(self);
341      ThrowRuntimeException("Unable to open trace file '%s'", trace_filename);
342      return;
343    }
344  }
345
346  Runtime* runtime = Runtime::Current();
347
348  // Enable count of allocs if specified in the flags.
349  bool enable_stats = false;
350
351  runtime->GetThreadList()->SuspendAll(__FUNCTION__);
352
353  // Create Trace object.
354  {
355    MutexLock mu(self, *Locks::trace_lock_);
356    if (the_trace_ != nullptr) {
357      LOG(ERROR) << "Trace already in progress, ignoring this request";
358    } else {
359      enable_stats = (flags && kTraceCountAllocs) != 0;
360      the_trace_ = new Trace(trace_file.release(), trace_filename, buffer_size, flags, output_mode,
361                             trace_mode);
362      if (trace_mode == TraceMode::kSampling) {
363        CHECK_PTHREAD_CALL(pthread_create, (&sampling_pthread_, nullptr, &RunSamplingThread,
364                                            reinterpret_cast<void*>(interval_us)),
365                                            "Sampling profiler thread");
366        the_trace_->interval_us_ = interval_us;
367      } else {
368        runtime->GetInstrumentation()->AddListener(the_trace_,
369                                                   instrumentation::Instrumentation::kMethodEntered |
370                                                   instrumentation::Instrumentation::kMethodExited |
371                                                   instrumentation::Instrumentation::kMethodUnwind);
372        // TODO: In full-PIC mode, we don't need to fully deopt.
373        runtime->GetInstrumentation()->EnableMethodTracing(kTracerInstrumentationKey);
374      }
375    }
376  }
377
378  runtime->GetThreadList()->ResumeAll();
379
380  // Can't call this when holding the mutator lock.
381  if (enable_stats) {
382    runtime->SetStatsEnabled(true);
383  }
384}
385
386void Trace::StopTracing(bool finish_tracing, bool flush_file) {
387  bool stop_alloc_counting = false;
388  Runtime* const runtime = Runtime::Current();
389  Trace* the_trace = nullptr;
390  pthread_t sampling_pthread = 0U;
391  {
392    MutexLock mu(Thread::Current(), *Locks::trace_lock_);
393    if (the_trace_ == nullptr) {
394      LOG(ERROR) << "Trace stop requested, but no trace currently running";
395    } else {
396      the_trace = the_trace_;
397      the_trace_ = nullptr;
398      sampling_pthread = sampling_pthread_;
399    }
400  }
401  // Make sure that we join before we delete the trace since we don't want to have
402  // the sampling thread access a stale pointer. This finishes since the sampling thread exits when
403  // the_trace_ is null.
404  if (sampling_pthread != 0U) {
405    CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, nullptr), "sampling thread shutdown");
406    sampling_pthread_ = 0U;
407  }
408  runtime->GetThreadList()->SuspendAll(__FUNCTION__);
409
410  if (the_trace != nullptr) {
411    stop_alloc_counting = (the_trace->flags_ & Trace::kTraceCountAllocs) != 0;
412    if (finish_tracing) {
413      the_trace->FinishTracing();
414    }
415
416    if (the_trace->trace_mode_ == TraceMode::kSampling) {
417      MutexLock mu(Thread::Current(), *Locks::thread_list_lock_);
418      runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, nullptr);
419    } else {
420      runtime->GetInstrumentation()->DisableMethodTracing(kTracerInstrumentationKey);
421      runtime->GetInstrumentation()->RemoveListener(
422          the_trace, instrumentation::Instrumentation::kMethodEntered |
423          instrumentation::Instrumentation::kMethodExited |
424          instrumentation::Instrumentation::kMethodUnwind);
425    }
426    if (the_trace->trace_file_.get() != nullptr) {
427      // Do not try to erase, so flush and close explicitly.
428      if (flush_file) {
429        if (the_trace->trace_file_->Flush() != 0) {
430          PLOG(WARNING) << "Could not flush trace file.";
431        }
432      } else {
433        the_trace->trace_file_->MarkUnchecked();  // Do not trigger guard.
434      }
435      if (the_trace->trace_file_->Close() != 0) {
436        PLOG(ERROR) << "Could not close trace file.";
437      }
438    }
439    delete the_trace;
440  }
441  runtime->GetThreadList()->ResumeAll();
442  if (stop_alloc_counting) {
443    // Can be racy since SetStatsEnabled is not guarded by any locks.
444    runtime->SetStatsEnabled(false);
445  }
446}
447
448void Trace::Abort() {
449  // Do not write anything anymore.
450  StopTracing(false, false);
451}
452
453void Trace::Stop() {
454  // Finish writing.
455  StopTracing(true, true);
456}
457
458void Trace::Shutdown() {
459  if (GetMethodTracingMode() != kTracingInactive) {
460    Stop();
461  }
462}
463
464void Trace::Pause() {
465  bool stop_alloc_counting = false;
466  Runtime* runtime = Runtime::Current();
467  Trace* the_trace = nullptr;
468
469  pthread_t sampling_pthread = 0U;
470  {
471    MutexLock mu(Thread::Current(), *Locks::trace_lock_);
472    if (the_trace_ == nullptr) {
473      LOG(ERROR) << "Trace pause requested, but no trace currently running";
474      return;
475    } else {
476      the_trace = the_trace_;
477      sampling_pthread = sampling_pthread_;
478    }
479  }
480
481  if (sampling_pthread != 0U) {
482    {
483      MutexLock mu(Thread::Current(), *Locks::trace_lock_);
484      the_trace_ = nullptr;
485    }
486    CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, nullptr), "sampling thread shutdown");
487    sampling_pthread_ = 0U;
488    {
489      MutexLock mu(Thread::Current(), *Locks::trace_lock_);
490      the_trace_ = the_trace;
491    }
492  }
493
494  if (the_trace != nullptr) {
495    runtime->GetThreadList()->SuspendAll(__FUNCTION__);
496    stop_alloc_counting = (the_trace->flags_ & Trace::kTraceCountAllocs) != 0;
497
498    if (the_trace->trace_mode_ == TraceMode::kSampling) {
499      MutexLock mu(Thread::Current(), *Locks::thread_list_lock_);
500      runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, nullptr);
501    } else {
502      runtime->GetInstrumentation()->DisableMethodTracing(kTracerInstrumentationKey);
503      runtime->GetInstrumentation()->RemoveListener(the_trace,
504                                                    instrumentation::Instrumentation::kMethodEntered |
505                                                    instrumentation::Instrumentation::kMethodExited |
506                                                    instrumentation::Instrumentation::kMethodUnwind);
507    }
508    runtime->GetThreadList()->ResumeAll();
509  }
510
511  if (stop_alloc_counting) {
512    // Can be racy since SetStatsEnabled is not guarded by any locks.
513    Runtime::Current()->SetStatsEnabled(false);
514  }
515}
516
517void Trace::Resume() {
518  Thread* self = Thread::Current();
519  Trace* the_trace;
520  {
521    MutexLock mu(self, *Locks::trace_lock_);
522    if (the_trace_ == nullptr) {
523      LOG(ERROR) << "No trace to resume (or sampling mode), ignoring this request";
524      return;
525    }
526    the_trace = the_trace_;
527  }
528
529  Runtime* runtime = Runtime::Current();
530
531  // Enable count of allocs if specified in the flags.
532  bool enable_stats = (the_trace->flags_ && kTraceCountAllocs) != 0;
533
534  runtime->GetThreadList()->SuspendAll(__FUNCTION__);
535
536  // Reenable.
537  if (the_trace->trace_mode_ == TraceMode::kSampling) {
538    CHECK_PTHREAD_CALL(pthread_create, (&sampling_pthread_, nullptr, &RunSamplingThread,
539        reinterpret_cast<void*>(the_trace->interval_us_)), "Sampling profiler thread");
540  } else {
541    runtime->GetInstrumentation()->AddListener(the_trace,
542                                               instrumentation::Instrumentation::kMethodEntered |
543                                               instrumentation::Instrumentation::kMethodExited |
544                                               instrumentation::Instrumentation::kMethodUnwind);
545    // TODO: In full-PIC mode, we don't need to fully deopt.
546    runtime->GetInstrumentation()->EnableMethodTracing(kTracerInstrumentationKey);
547  }
548
549  runtime->GetThreadList()->ResumeAll();
550
551  // Can't call this when holding the mutator lock.
552  if (enable_stats) {
553    runtime->SetStatsEnabled(true);
554  }
555}
556
557TracingMode Trace::GetMethodTracingMode() {
558  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
559  if (the_trace_ == nullptr) {
560    return kTracingInactive;
561  } else {
562    switch (the_trace_->trace_mode_) {
563      case TraceMode::kSampling:
564        return kSampleProfilingActive;
565      case TraceMode::kMethodTracing:
566        return kMethodTracingActive;
567    }
568    LOG(FATAL) << "Unreachable";
569    UNREACHABLE();
570  }
571}
572
573static constexpr size_t kMinBufSize = 18U;  // Trace header is up to 18B.
574
575Trace::Trace(File* trace_file, const char* trace_name, size_t buffer_size, int flags,
576             TraceOutputMode output_mode, TraceMode trace_mode)
577    : trace_file_(trace_file),
578      buf_(new uint8_t[std::max(kMinBufSize, buffer_size)]()),
579      flags_(flags), trace_output_mode_(output_mode), trace_mode_(trace_mode),
580      clock_source_(default_clock_source_),
581      buffer_size_(std::max(kMinBufSize, buffer_size)),
582      start_time_(MicroTime()), clock_overhead_ns_(GetClockOverheadNanoSeconds()), cur_offset_(0),
583      overflow_(false), interval_us_(0), streaming_lock_(nullptr),
584      unique_methods_lock_(new Mutex("unique methods lock", kTracingUniqueMethodsLock)) {
585  uint16_t trace_version = GetTraceVersion(clock_source_);
586  if (output_mode == TraceOutputMode::kStreaming) {
587    trace_version |= 0xF0U;
588  }
589  // Set up the beginning of the trace.
590  memset(buf_.get(), 0, kTraceHeaderLength);
591  Append4LE(buf_.get(), kTraceMagicValue);
592  Append2LE(buf_.get() + 4, trace_version);
593  Append2LE(buf_.get() + 6, kTraceHeaderLength);
594  Append8LE(buf_.get() + 8, start_time_);
595  if (trace_version >= kTraceVersionDualClock) {
596    uint16_t record_size = GetRecordSize(clock_source_);
597    Append2LE(buf_.get() + 16, record_size);
598  }
599  static_assert(18 <= kMinBufSize, "Minimum buffer size not large enough for trace header");
600
601  // Update current offset.
602  cur_offset_.StoreRelaxed(kTraceHeaderLength);
603
604  if (output_mode == TraceOutputMode::kStreaming) {
605    streaming_file_name_ = trace_name;
606    streaming_lock_ = new Mutex("tracing lock", LockLevel::kTracingStreamingLock);
607    seen_threads_.reset(new ThreadIDBitSet());
608  }
609}
610
611Trace::~Trace() {
612  delete streaming_lock_;
613  delete unique_methods_lock_;
614}
615
616static uint64_t ReadBytes(uint8_t* buf, size_t bytes) {
617  uint64_t ret = 0;
618  for (size_t i = 0; i < bytes; ++i) {
619    ret |= static_cast<uint64_t>(buf[i]) << (i * 8);
620  }
621  return ret;
622}
623
624void Trace::DumpBuf(uint8_t* buf, size_t buf_size, TraceClockSource clock_source) {
625  uint8_t* ptr = buf + kTraceHeaderLength;
626  uint8_t* end = buf + buf_size;
627
628  while (ptr < end) {
629    uint32_t tmid = ReadBytes(ptr + 2, sizeof(tmid));
630    ArtMethod* method = DecodeTraceMethod(tmid);
631    TraceAction action = DecodeTraceAction(tmid);
632    LOG(INFO) << PrettyMethod(method) << " " << static_cast<int>(action);
633    ptr += GetRecordSize(clock_source);
634  }
635}
636
637static void GetVisitedMethodsFromBitSets(
638    const std::map<const DexFile*, DexIndexBitSet*>& seen_methods,
639    std::set<ArtMethod*>* visited_methods) SHARED_REQUIRES(Locks::mutator_lock_) {
640  ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
641  for (auto& e : seen_methods) {
642    DexIndexBitSet* bit_set = e.second;
643    mirror::DexCache* dex_cache = class_linker->FindDexCache(*e.first);
644    for (uint32_t i = 0; i < bit_set->size(); ++i) {
645      if ((*bit_set)[i]) {
646        visited_methods->insert(dex_cache->GetResolvedMethod(i, sizeof(void*)));
647      }
648    }
649  }
650}
651
652void Trace::FinishTracing() {
653  size_t final_offset = 0;
654
655  std::set<ArtMethod*> visited_methods;
656  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
657    // Write the secondary file with all the method names.
658    GetVisitedMethodsFromBitSets(seen_methods_, &visited_methods);
659
660    // Clean up.
661    STLDeleteValues(&seen_methods_);
662  } else {
663    final_offset = cur_offset_.LoadRelaxed();
664    GetVisitedMethods(final_offset, &visited_methods);
665  }
666
667  // Compute elapsed time.
668  uint64_t elapsed = MicroTime() - start_time_;
669
670  std::ostringstream os;
671
672  os << StringPrintf("%cversion\n", kTraceTokenChar);
673  os << StringPrintf("%d\n", GetTraceVersion(clock_source_));
674  os << StringPrintf("data-file-overflow=%s\n", overflow_ ? "true" : "false");
675  if (UseThreadCpuClock()) {
676    if (UseWallClock()) {
677      os << StringPrintf("clock=dual\n");
678    } else {
679      os << StringPrintf("clock=thread-cpu\n");
680    }
681  } else {
682    os << StringPrintf("clock=wall\n");
683  }
684  os << StringPrintf("elapsed-time-usec=%" PRIu64 "\n", elapsed);
685  if (trace_output_mode_ != TraceOutputMode::kStreaming) {
686    size_t num_records = (final_offset - kTraceHeaderLength) / GetRecordSize(clock_source_);
687    os << StringPrintf("num-method-calls=%zd\n", num_records);
688  }
689  os << StringPrintf("clock-call-overhead-nsec=%d\n", clock_overhead_ns_);
690  os << StringPrintf("vm=art\n");
691  os << StringPrintf("pid=%d\n", getpid());
692  if ((flags_ & kTraceCountAllocs) != 0) {
693    os << StringPrintf("alloc-count=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_OBJECTS));
694    os << StringPrintf("alloc-size=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_BYTES));
695    os << StringPrintf("gc-count=%d\n", Runtime::Current()->GetStat(KIND_GC_INVOCATIONS));
696  }
697  os << StringPrintf("%cthreads\n", kTraceTokenChar);
698  DumpThreadList(os);
699  os << StringPrintf("%cmethods\n", kTraceTokenChar);
700  DumpMethodList(os, visited_methods);
701  os << StringPrintf("%cend\n", kTraceTokenChar);
702  std::string header(os.str());
703
704  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
705    File file;
706    if (!file.Open(streaming_file_name_ + ".sec", O_CREAT | O_WRONLY)) {
707      LOG(WARNING) << "Could not open secondary trace file!";
708      return;
709    }
710    if (!file.WriteFully(header.c_str(), header.length())) {
711      file.Erase();
712      std::string detail(StringPrintf("Trace data write failed: %s", strerror(errno)));
713      PLOG(ERROR) << detail;
714      ThrowRuntimeException("%s", detail.c_str());
715    }
716    if (file.FlushCloseOrErase() != 0) {
717      PLOG(ERROR) << "Could not write secondary file";
718    }
719  } else {
720    if (trace_file_.get() == nullptr) {
721      iovec iov[2];
722      iov[0].iov_base = reinterpret_cast<void*>(const_cast<char*>(header.c_str()));
723      iov[0].iov_len = header.length();
724      iov[1].iov_base = buf_.get();
725      iov[1].iov_len = final_offset;
726      Dbg::DdmSendChunkV(CHUNK_TYPE("MPSE"), iov, 2);
727      const bool kDumpTraceInfo = false;
728      if (kDumpTraceInfo) {
729        LOG(INFO) << "Trace sent:\n" << header;
730        DumpBuf(buf_.get(), final_offset, clock_source_);
731      }
732    } else {
733      if (!trace_file_->WriteFully(header.c_str(), header.length()) ||
734          !trace_file_->WriteFully(buf_.get(), final_offset)) {
735        std::string detail(StringPrintf("Trace data write failed: %s", strerror(errno)));
736        PLOG(ERROR) << detail;
737        ThrowRuntimeException("%s", detail.c_str());
738      }
739    }
740  }
741}
742
743void Trace::DexPcMoved(Thread* thread, mirror::Object* this_object,
744                       ArtMethod* method, uint32_t new_dex_pc) {
745  UNUSED(thread, this_object, method, new_dex_pc);
746  // We're not recorded to listen to this kind of event, so complain.
747  LOG(ERROR) << "Unexpected dex PC event in tracing " << PrettyMethod(method) << " " << new_dex_pc;
748}
749
750void Trace::FieldRead(Thread* thread, mirror::Object* this_object,
751                       ArtMethod* method, uint32_t dex_pc, ArtField* field)
752    SHARED_REQUIRES(Locks::mutator_lock_) {
753  UNUSED(thread, this_object, method, dex_pc, field);
754  // We're not recorded to listen to this kind of event, so complain.
755  LOG(ERROR) << "Unexpected field read event in tracing " << PrettyMethod(method) << " " << dex_pc;
756}
757
758void Trace::FieldWritten(Thread* thread, mirror::Object* this_object,
759                          ArtMethod* method, uint32_t dex_pc, ArtField* field,
760                          const JValue& field_value)
761    SHARED_REQUIRES(Locks::mutator_lock_) {
762  UNUSED(thread, this_object, method, dex_pc, field, field_value);
763  // We're not recorded to listen to this kind of event, so complain.
764  LOG(ERROR) << "Unexpected field write event in tracing " << PrettyMethod(method) << " " << dex_pc;
765}
766
767void Trace::MethodEntered(Thread* thread, mirror::Object* this_object ATTRIBUTE_UNUSED,
768                          ArtMethod* method, uint32_t dex_pc ATTRIBUTE_UNUSED) {
769  uint32_t thread_clock_diff = 0;
770  uint32_t wall_clock_diff = 0;
771  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
772  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodEntered,
773                      thread_clock_diff, wall_clock_diff);
774}
775
776void Trace::MethodExited(Thread* thread, mirror::Object* this_object ATTRIBUTE_UNUSED,
777                         ArtMethod* method, uint32_t dex_pc ATTRIBUTE_UNUSED,
778                         const JValue& return_value ATTRIBUTE_UNUSED) {
779  uint32_t thread_clock_diff = 0;
780  uint32_t wall_clock_diff = 0;
781  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
782  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodExited,
783                      thread_clock_diff, wall_clock_diff);
784}
785
786void Trace::MethodUnwind(Thread* thread, mirror::Object* this_object ATTRIBUTE_UNUSED,
787                         ArtMethod* method, uint32_t dex_pc ATTRIBUTE_UNUSED) {
788  uint32_t thread_clock_diff = 0;
789  uint32_t wall_clock_diff = 0;
790  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
791  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodUnwind,
792                      thread_clock_diff, wall_clock_diff);
793}
794
795void Trace::ExceptionCaught(Thread* thread, mirror::Throwable* exception_object)
796    SHARED_REQUIRES(Locks::mutator_lock_) {
797  UNUSED(thread, exception_object);
798  LOG(ERROR) << "Unexpected exception caught event in tracing";
799}
800
801void Trace::BackwardBranch(Thread* /*thread*/, ArtMethod* method,
802                           int32_t /*dex_pc_offset*/)
803      SHARED_REQUIRES(Locks::mutator_lock_) {
804  LOG(ERROR) << "Unexpected backward branch event in tracing" << PrettyMethod(method);
805}
806
807void Trace::ReadClocks(Thread* thread, uint32_t* thread_clock_diff, uint32_t* wall_clock_diff) {
808  if (UseThreadCpuClock()) {
809    uint64_t clock_base = thread->GetTraceClockBase();
810    if (UNLIKELY(clock_base == 0)) {
811      // First event, record the base time in the map.
812      uint64_t time = thread->GetCpuMicroTime();
813      thread->SetTraceClockBase(time);
814    } else {
815      *thread_clock_diff = thread->GetCpuMicroTime() - clock_base;
816    }
817  }
818  if (UseWallClock()) {
819    *wall_clock_diff = MicroTime() - start_time_;
820  }
821}
822
823bool Trace::RegisterMethod(ArtMethod* method) {
824  mirror::DexCache* dex_cache = method->GetDexCache();
825  const DexFile* dex_file = dex_cache->GetDexFile();
826  auto* resolved_method = dex_cache->GetResolvedMethod(method->GetDexMethodIndex(), sizeof(void*));
827  if (resolved_method != method) {
828    DCHECK(resolved_method == nullptr);
829    dex_cache->SetResolvedMethod(method->GetDexMethodIndex(), method, sizeof(void*));
830  }
831  if (seen_methods_.find(dex_file) == seen_methods_.end()) {
832    seen_methods_.insert(std::make_pair(dex_file, new DexIndexBitSet()));
833  }
834  DexIndexBitSet* bit_set = seen_methods_.find(dex_file)->second;
835  if (!(*bit_set)[method->GetDexMethodIndex()]) {
836    bit_set->set(method->GetDexMethodIndex());
837    return true;
838  }
839  return false;
840}
841
842bool Trace::RegisterThread(Thread* thread) {
843  pid_t tid = thread->GetTid();
844  CHECK_LT(0U, static_cast<uint32_t>(tid));
845  CHECK_LT(static_cast<uint32_t>(tid), 65536U);
846
847  if (!(*seen_threads_)[tid]) {
848    seen_threads_->set(tid);
849    return true;
850  }
851  return false;
852}
853
854std::string Trace::GetMethodLine(ArtMethod* method) {
855  method = method->GetInterfaceMethodIfProxy(sizeof(void*));
856  return StringPrintf("%p\t%s\t%s\t%s\t%s\n",
857                      reinterpret_cast<void*>((EncodeTraceMethod(method) << TraceActionBits)),
858      PrettyDescriptor(method->GetDeclaringClassDescriptor()).c_str(), method->GetName(),
859      method->GetSignature().ToString().c_str(), method->GetDeclaringClassSourceFile());
860}
861
862void Trace::WriteToBuf(const uint8_t* src, size_t src_size) {
863  int32_t old_offset = cur_offset_.LoadRelaxed();
864  int32_t new_offset = old_offset + static_cast<int32_t>(src_size);
865  if (dchecked_integral_cast<size_t>(new_offset) > buffer_size_) {
866    // Flush buffer.
867    if (!trace_file_->WriteFully(buf_.get(), old_offset)) {
868      PLOG(WARNING) << "Failed streaming a tracing event.";
869    }
870
871    // Check whether the data is too large for the buffer, then write immediately.
872    if (src_size >= buffer_size_) {
873      if (!trace_file_->WriteFully(src, src_size)) {
874        PLOG(WARNING) << "Failed streaming a tracing event.";
875      }
876      cur_offset_.StoreRelease(0);  // Buffer is empty now.
877      return;
878    }
879
880    old_offset = 0;
881    new_offset = static_cast<int32_t>(src_size);
882  }
883  cur_offset_.StoreRelease(new_offset);
884  // Fill in data.
885  memcpy(buf_.get() + old_offset, src, src_size);
886}
887
888void Trace::LogMethodTraceEvent(Thread* thread, ArtMethod* method,
889                                instrumentation::Instrumentation::InstrumentationEvent event,
890                                uint32_t thread_clock_diff, uint32_t wall_clock_diff) {
891  // Advance cur_offset_ atomically.
892  int32_t new_offset;
893  int32_t old_offset = 0;
894
895  // We do a busy loop here trying to acquire the next offset.
896  if (trace_output_mode_ != TraceOutputMode::kStreaming) {
897    do {
898      old_offset = cur_offset_.LoadRelaxed();
899      new_offset = old_offset + GetRecordSize(clock_source_);
900      if (static_cast<size_t>(new_offset) > buffer_size_) {
901        overflow_ = true;
902        return;
903      }
904    } while (!cur_offset_.CompareExchangeWeakSequentiallyConsistent(old_offset, new_offset));
905  }
906
907  TraceAction action = kTraceMethodEnter;
908  switch (event) {
909    case instrumentation::Instrumentation::kMethodEntered:
910      action = kTraceMethodEnter;
911      break;
912    case instrumentation::Instrumentation::kMethodExited:
913      action = kTraceMethodExit;
914      break;
915    case instrumentation::Instrumentation::kMethodUnwind:
916      action = kTraceUnroll;
917      break;
918    default:
919      UNIMPLEMENTED(FATAL) << "Unexpected event: " << event;
920  }
921
922  uint32_t method_value = EncodeTraceMethodAndAction(method, action);
923
924  // Write data
925  uint8_t* ptr;
926  static constexpr size_t kPacketSize = 14U;  // The maximum size of data in a packet.
927  uint8_t stack_buf[kPacketSize];             // Space to store a packet when in streaming mode.
928  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
929    ptr = stack_buf;
930  } else {
931    ptr = buf_.get() + old_offset;
932  }
933
934  Append2LE(ptr, thread->GetTid());
935  Append4LE(ptr + 2, method_value);
936  ptr += 6;
937
938  if (UseThreadCpuClock()) {
939    Append4LE(ptr, thread_clock_diff);
940    ptr += 4;
941  }
942  if (UseWallClock()) {
943    Append4LE(ptr, wall_clock_diff);
944  }
945  static_assert(kPacketSize == 2 + 4 + 4 + 4, "Packet size incorrect.");
946
947  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
948    MutexLock mu(Thread::Current(), *streaming_lock_);  // To serialize writing.
949    if (RegisterMethod(method)) {
950      // Write a special block with the name.
951      std::string method_line(GetMethodLine(method));
952      uint8_t buf2[5];
953      Append2LE(buf2, 0);
954      buf2[2] = kOpNewMethod;
955      Append2LE(buf2 + 3, static_cast<uint16_t>(method_line.length()));
956      WriteToBuf(buf2, sizeof(buf2));
957      WriteToBuf(reinterpret_cast<const uint8_t*>(method_line.c_str()), method_line.length());
958    }
959    if (RegisterThread(thread)) {
960      // It might be better to postpone this. Threads might not have received names...
961      std::string thread_name;
962      thread->GetThreadName(thread_name);
963      uint8_t buf2[7];
964      Append2LE(buf2, 0);
965      buf2[2] = kOpNewThread;
966      Append2LE(buf2 + 3, static_cast<uint16_t>(thread->GetTid()));
967      Append2LE(buf2 + 5, static_cast<uint16_t>(thread_name.length()));
968      WriteToBuf(buf2, sizeof(buf2));
969      WriteToBuf(reinterpret_cast<const uint8_t*>(thread_name.c_str()), thread_name.length());
970    }
971    WriteToBuf(stack_buf, sizeof(stack_buf));
972  }
973}
974
975void Trace::GetVisitedMethods(size_t buf_size,
976                              std::set<ArtMethod*>* visited_methods) {
977  uint8_t* ptr = buf_.get() + kTraceHeaderLength;
978  uint8_t* end = buf_.get() + buf_size;
979
980  while (ptr < end) {
981    uint32_t tmid = ReadBytes(ptr + 2, sizeof(tmid));
982    ArtMethod* method = DecodeTraceMethod(tmid);
983    visited_methods->insert(method);
984    ptr += GetRecordSize(clock_source_);
985  }
986}
987
988void Trace::DumpMethodList(std::ostream& os, const std::set<ArtMethod*>& visited_methods) {
989  for (const auto& method : visited_methods) {
990    os << GetMethodLine(method);
991  }
992}
993
994static void DumpThread(Thread* t, void* arg) {
995  std::ostream& os = *reinterpret_cast<std::ostream*>(arg);
996  std::string name;
997  t->GetThreadName(name);
998  os << t->GetTid() << "\t" << name << "\n";
999}
1000
1001void Trace::DumpThreadList(std::ostream& os) {
1002  Thread* self = Thread::Current();
1003  for (auto it : exited_threads_) {
1004    os << it.first << "\t" << it.second << "\n";
1005  }
1006  Locks::thread_list_lock_->AssertNotHeld(self);
1007  MutexLock mu(self, *Locks::thread_list_lock_);
1008  Runtime::Current()->GetThreadList()->ForEach(DumpThread, &os);
1009}
1010
1011void Trace::StoreExitingThreadInfo(Thread* thread) {
1012  MutexLock mu(thread, *Locks::trace_lock_);
1013  if (the_trace_ != nullptr) {
1014    std::string name;
1015    thread->GetThreadName(name);
1016    // The same thread/tid may be used multiple times. As SafeMap::Put does not allow to override
1017    // a previous mapping, use SafeMap::Overwrite.
1018    the_trace_->exited_threads_.Overwrite(thread->GetTid(), name);
1019  }
1020}
1021
1022Trace::TraceOutputMode Trace::GetOutputMode() {
1023  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1024  CHECK(the_trace_ != nullptr) << "Trace output mode requested, but no trace currently running";
1025  return the_trace_->trace_output_mode_;
1026}
1027
1028Trace::TraceMode Trace::GetMode() {
1029  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1030  CHECK(the_trace_ != nullptr) << "Trace mode requested, but no trace currently running";
1031  return the_trace_->trace_mode_;
1032}
1033
1034size_t Trace::GetBufferSize() {
1035  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1036  CHECK(the_trace_ != nullptr) << "Trace mode requested, but no trace currently running";
1037  return the_trace_->buffer_size_;
1038}
1039
1040}  // namespace art
1041