trace.cc revision ef7d42fca18c16fbaf103822ad16f23246e2905d 
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
21#include "base/stl_util.h"
22#include "base/unix_file/fd_file.h"
23#include "class_linker.h"
24#include "common_throws.h"
25#include "debugger.h"
26#include "dex_file-inl.h"
27#include "instrumentation.h"
28#include "mirror/art_method-inl.h"
29#include "mirror/class-inl.h"
30#include "mirror/dex_cache.h"
31#include "mirror/object_array-inl.h"
32#include "mirror/object-inl.h"
33#include "object_utils.h"
34#include "os.h"
35#include "scoped_thread_state_change.h"
36#include "ScopedLocalRef.h"
37#include "thread.h"
38#include "thread_list.h"
39#if !defined(ART_USE_PORTABLE_COMPILER)
40#include "entrypoints/quick/quick_entrypoints.h"
41#endif
42
43namespace art {
44
45// File format:
46//     header
47//     record 0
48//     record 1
49//     ...
50//
51// Header format:
52//     u4  magic ('SLOW')
53//     u2  version
54//     u2  offset to data
55//     u8  start date/time in usec
56//     u2  record size in bytes (version >= 2 only)
57//     ... padding to 32 bytes
58//
59// Record format v1:
60//     u1  thread ID
61//     u4  method ID | method action
62//     u4  time delta since start, in usec
63//
64// Record format v2:
65//     u2  thread ID
66//     u4  method ID | method action
67//     u4  time delta since start, in usec
68//
69// Record format v3:
70//     u2  thread ID
71//     u4  method ID | method action
72//     u4  time delta since start, in usec
73//     u4  wall time since start, in usec (when clock == "dual" only)
74//
75// 32 bits of microseconds is 70 minutes.
76//
77// All values are stored in little-endian order.
78
79enum TraceAction {
80    kTraceMethodEnter = 0x00,       // method entry
81    kTraceMethodExit = 0x01,        // method exit
82    kTraceUnroll = 0x02,            // method exited by exception unrolling
83    // 0x03 currently unused
84    kTraceMethodActionMask = 0x03,  // two bits
85};
86
87class BuildStackTraceVisitor : public StackVisitor {
88 public:
89  explicit BuildStackTraceVisitor(Thread* thread) : StackVisitor(thread, NULL),
90      method_trace_(Trace::AllocStackTrace()) {}
91
92  bool VisitFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
93    mirror::ArtMethod* m = GetMethod();
94    // Ignore runtime frames (in particular callee save).
95    if (!m->IsRuntimeMethod()) {
96      method_trace_->push_back(m);
97    }
98    return true;
99  }
100
101  // Returns a stack trace where the topmost frame corresponds with the first element of the vector.
102  std::vector<mirror::ArtMethod*>* GetStackTrace() const {
103    return method_trace_;
104  }
105
106 private:
107  std::vector<mirror::ArtMethod*>* const method_trace_;
108};
109
110static const char     kTraceTokenChar             = '*';
111static const uint16_t kTraceHeaderLength          = 32;
112static const uint32_t kTraceMagicValue            = 0x574f4c53;
113static const uint16_t kTraceVersionSingleClock    = 2;
114static const uint16_t kTraceVersionDualClock      = 3;
115static const uint16_t kTraceRecordSizeSingleClock = 10;  // using v2
116static const uint16_t kTraceRecordSizeDualClock   = 14;  // using v3 with two timestamps
117
118#if defined(HAVE_POSIX_CLOCKS)
119ProfilerClockSource Trace::default_clock_source_ = kProfilerClockSourceDual;
120#else
121ProfilerClockSource Trace::default_clock_source_ = kProfilerClockSourceWall;
122#endif
123
124Trace* volatile Trace::the_trace_ = NULL;
125pthread_t Trace::sampling_pthread_ = 0U;
126UniquePtr<std::vector<mirror::ArtMethod*> > Trace::temp_stack_trace_;
127
128static mirror::ArtMethod* DecodeTraceMethodId(uint32_t tmid) {
129  return reinterpret_cast<mirror::ArtMethod*>(tmid & ~kTraceMethodActionMask);
130}
131
132static TraceAction DecodeTraceAction(uint32_t tmid) {
133  return static_cast<TraceAction>(tmid & kTraceMethodActionMask);
134}
135
136static uint32_t EncodeTraceMethodAndAction(mirror::ArtMethod* method,
137                                           TraceAction action) {
138  uint32_t tmid = PointerToLowMemUInt32(method) | action;
139  DCHECK_EQ(method, DecodeTraceMethodId(tmid));
140  return tmid;
141}
142
143std::vector<mirror::ArtMethod*>* Trace::AllocStackTrace() {
144  if (temp_stack_trace_.get() != NULL) {
145    return temp_stack_trace_.release();
146  } else {
147    return new std::vector<mirror::ArtMethod*>();
148  }
149}
150
151void Trace::FreeStackTrace(std::vector<mirror::ArtMethod*>* stack_trace) {
152  stack_trace->clear();
153  temp_stack_trace_.reset(stack_trace);
154}
155
156void Trace::SetDefaultClockSource(ProfilerClockSource clock_source) {
157#if defined(HAVE_POSIX_CLOCKS)
158  default_clock_source_ = clock_source;
159#else
160  if (clock_source != kProfilerClockSourceWall) {
161    LOG(WARNING) << "Ignoring tracing request to use CPU time.";
162  }
163#endif
164}
165
166static uint16_t GetTraceVersion(ProfilerClockSource clock_source) {
167  return (clock_source == kProfilerClockSourceDual) ? kTraceVersionDualClock
168                                                    : kTraceVersionSingleClock;
169}
170
171static uint16_t GetRecordSize(ProfilerClockSource clock_source) {
172  return (clock_source == kProfilerClockSourceDual) ? kTraceRecordSizeDualClock
173                                                    : kTraceRecordSizeSingleClock;
174}
175
176bool Trace::UseThreadCpuClock() {
177  return (clock_source_ == kProfilerClockSourceThreadCpu) ||
178      (clock_source_ == kProfilerClockSourceDual);
179}
180
181bool Trace::UseWallClock() {
182  return (clock_source_ == kProfilerClockSourceWall) ||
183      (clock_source_ == kProfilerClockSourceDual);
184}
185
186static void MeasureClockOverhead(Trace* trace) {
187  if (trace->UseThreadCpuClock()) {
188    Thread::Current()->GetCpuMicroTime();
189  }
190  if (trace->UseWallClock()) {
191    MicroTime();
192  }
193}
194
195// Compute an average time taken to measure clocks.
196static uint32_t GetClockOverheadNanoSeconds(Trace* trace) {
197  Thread* self = Thread::Current();
198  uint64_t start = self->GetCpuMicroTime();
199
200  for (int i = 4000; i > 0; i--) {
201    MeasureClockOverhead(trace);
202    MeasureClockOverhead(trace);
203    MeasureClockOverhead(trace);
204    MeasureClockOverhead(trace);
205    MeasureClockOverhead(trace);
206    MeasureClockOverhead(trace);
207    MeasureClockOverhead(trace);
208    MeasureClockOverhead(trace);
209  }
210
211  uint64_t elapsed_us = self->GetCpuMicroTime() - start;
212  return static_cast<uint32_t>(elapsed_us / 32);
213}
214
215// TODO: put this somewhere with the big-endian equivalent used by JDWP.
216static void Append2LE(uint8_t* buf, uint16_t val) {
217  *buf++ = static_cast<uint8_t>(val);
218  *buf++ = static_cast<uint8_t>(val >> 8);
219}
220
221// TODO: put this somewhere with the big-endian equivalent used by JDWP.
222static void Append4LE(uint8_t* buf, uint32_t val) {
223  *buf++ = static_cast<uint8_t>(val);
224  *buf++ = static_cast<uint8_t>(val >> 8);
225  *buf++ = static_cast<uint8_t>(val >> 16);
226  *buf++ = static_cast<uint8_t>(val >> 24);
227}
228
229// TODO: put this somewhere with the big-endian equivalent used by JDWP.
230static void Append8LE(uint8_t* buf, uint64_t val) {
231  *buf++ = static_cast<uint8_t>(val);
232  *buf++ = static_cast<uint8_t>(val >> 8);
233  *buf++ = static_cast<uint8_t>(val >> 16);
234  *buf++ = static_cast<uint8_t>(val >> 24);
235  *buf++ = static_cast<uint8_t>(val >> 32);
236  *buf++ = static_cast<uint8_t>(val >> 40);
237  *buf++ = static_cast<uint8_t>(val >> 48);
238  *buf++ = static_cast<uint8_t>(val >> 56);
239}
240
241static void GetSample(Thread* thread, void* arg) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
242  BuildStackTraceVisitor build_trace_visitor(thread);
243  build_trace_visitor.WalkStack();
244  std::vector<mirror::ArtMethod*>* stack_trace = build_trace_visitor.GetStackTrace();
245  Trace* the_trace = reinterpret_cast<Trace*>(arg);
246  the_trace->CompareAndUpdateStackTrace(thread, stack_trace);
247}
248
249static void ClearThreadStackTraceAndClockBase(Thread* thread, void* arg) {
250  thread->SetTraceClockBase(0);
251  std::vector<mirror::ArtMethod*>* stack_trace = thread->GetStackTraceSample();
252  thread->SetStackTraceSample(NULL);
253  delete stack_trace;
254}
255
256void Trace::CompareAndUpdateStackTrace(Thread* thread,
257                                       std::vector<mirror::ArtMethod*>* stack_trace) {
258  CHECK_EQ(pthread_self(), sampling_pthread_);
259  std::vector<mirror::ArtMethod*>* old_stack_trace = thread->GetStackTraceSample();
260  // Update the thread's stack trace sample.
261  thread->SetStackTraceSample(stack_trace);
262  // Read timer clocks to use for all events in this trace.
263  uint32_t thread_clock_diff = 0;
264  uint32_t wall_clock_diff = 0;
265  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
266  if (old_stack_trace == NULL) {
267    // If there's no previous stack trace sample for this thread, log an entry event for all
268    // methods in the trace.
269    for (std::vector<mirror::ArtMethod*>::reverse_iterator rit = stack_trace->rbegin();
270         rit != stack_trace->rend(); ++rit) {
271      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
272                          thread_clock_diff, wall_clock_diff);
273    }
274  } else {
275    // If there's a previous stack trace for this thread, diff the traces and emit entry and exit
276    // events accordingly.
277    std::vector<mirror::ArtMethod*>::reverse_iterator old_rit = old_stack_trace->rbegin();
278    std::vector<mirror::ArtMethod*>::reverse_iterator rit = stack_trace->rbegin();
279    // Iterate bottom-up over both traces until there's a difference between them.
280    while (old_rit != old_stack_trace->rend() && rit != stack_trace->rend() && *old_rit == *rit) {
281      old_rit++;
282      rit++;
283    }
284    // Iterate top-down over the old trace until the point where they differ, emitting exit events.
285    for (std::vector<mirror::ArtMethod*>::iterator old_it = old_stack_trace->begin();
286         old_it != old_rit.base(); ++old_it) {
287      LogMethodTraceEvent(thread, *old_it, instrumentation::Instrumentation::kMethodExited,
288                          thread_clock_diff, wall_clock_diff);
289    }
290    // Iterate bottom-up over the new trace from the point where they differ, emitting entry events.
291    for (; rit != stack_trace->rend(); ++rit) {
292      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
293                          thread_clock_diff, wall_clock_diff);
294    }
295    FreeStackTrace(old_stack_trace);
296  }
297}
298
299void* Trace::RunSamplingThread(void* arg) {
300  Runtime* runtime = Runtime::Current();
301  intptr_t interval_us = reinterpret_cast<intptr_t>(arg);
302  CHECK_GE(interval_us, 0);
303  CHECK(runtime->AttachCurrentThread("Sampling Profiler", true, runtime->GetSystemThreadGroup(),
304                                     !runtime->IsCompiler()));
305
306  while (true) {
307    usleep(interval_us);
308    ATRACE_BEGIN("Profile sampling");
309    Thread* self = Thread::Current();
310    Trace* the_trace;
311    {
312      MutexLock mu(self, *Locks::trace_lock_);
313      the_trace = the_trace_;
314      if (the_trace == NULL) {
315        break;
316      }
317    }
318
319    runtime->GetThreadList()->SuspendAll();
320    {
321      MutexLock mu(self, *Locks::thread_list_lock_);
322      runtime->GetThreadList()->ForEach(GetSample, the_trace);
323    }
324    runtime->GetThreadList()->ResumeAll();
325    ATRACE_END();
326  }
327
328  runtime->DetachCurrentThread();
329  return NULL;
330}
331
332void Trace::Start(const char* trace_filename, int trace_fd, int buffer_size, int flags,
333                  bool direct_to_ddms, bool sampling_enabled, int interval_us) {
334  Thread* self = Thread::Current();
335  {
336    MutexLock mu(self, *Locks::trace_lock_);
337    if (the_trace_ != NULL) {
338      LOG(ERROR) << "Trace already in progress, ignoring this request";
339      return;
340    }
341  }
342  Runtime* runtime = Runtime::Current();
343  runtime->GetThreadList()->SuspendAll();
344
345  // Open trace file if not going directly to ddms.
346  UniquePtr<File> trace_file;
347  if (!direct_to_ddms) {
348    if (trace_fd < 0) {
349      trace_file.reset(OS::CreateEmptyFile(trace_filename));
350    } else {
351      trace_file.reset(new File(trace_fd, "tracefile"));
352      trace_file->DisableAutoClose();
353    }
354    if (trace_file.get() == NULL) {
355      PLOG(ERROR) << "Unable to open trace file '" << trace_filename << "'";
356      runtime->GetThreadList()->ResumeAll();
357      ScopedObjectAccess soa(self);
358      ThrowRuntimeException("Unable to open trace file '%s'", trace_filename);
359      return;
360    }
361  }
362
363  // Create Trace object.
364  {
365    MutexLock mu(self, *Locks::trace_lock_);
366    if (the_trace_ != NULL) {
367      LOG(ERROR) << "Trace already in progress, ignoring this request";
368    } else {
369      the_trace_ = new Trace(trace_file.release(), buffer_size, flags, sampling_enabled);
370
371      // Enable count of allocs if specified in the flags.
372      if ((flags && kTraceCountAllocs) != 0) {
373        runtime->SetStatsEnabled(true);
374      }
375
376
377
378      if (sampling_enabled) {
379        CHECK_PTHREAD_CALL(pthread_create, (&sampling_pthread_, NULL, &RunSamplingThread,
380                                            reinterpret_cast<void*>(interval_us)),
381                                            "Sampling profiler thread");
382      } else {
383        runtime->GetInstrumentation()->AddListener(the_trace_,
384                                                   instrumentation::Instrumentation::kMethodEntered |
385                                                   instrumentation::Instrumentation::kMethodExited |
386                                                   instrumentation::Instrumentation::kMethodUnwind);
387        runtime->GetInstrumentation()->EnableMethodTracing();
388      }
389    }
390  }
391  runtime->GetThreadList()->ResumeAll();
392}
393
394void Trace::Stop() {
395  Runtime* runtime = Runtime::Current();
396  runtime->GetThreadList()->SuspendAll();
397  Trace* the_trace = NULL;
398  pthread_t sampling_pthread = 0U;
399  {
400    MutexLock mu(Thread::Current(), *Locks::trace_lock_);
401    if (the_trace_ == NULL) {
402      LOG(ERROR) << "Trace stop requested, but no trace currently running";
403    } else {
404      the_trace = the_trace_;
405      the_trace_ = NULL;
406      sampling_pthread = sampling_pthread_;
407      sampling_pthread_ = 0U;
408    }
409  }
410  if (the_trace != NULL) {
411    the_trace->FinishTracing();
412
413    if (the_trace->sampling_enabled_) {
414      MutexLock mu(Thread::Current(), *Locks::thread_list_lock_);
415      runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, NULL);
416    } else {
417      runtime->GetInstrumentation()->DisableMethodTracing();
418      runtime->GetInstrumentation()->RemoveListener(the_trace,
419                                                    instrumentation::Instrumentation::kMethodEntered |
420                                                    instrumentation::Instrumentation::kMethodExited |
421                                                    instrumentation::Instrumentation::kMethodUnwind);
422    }
423    delete the_trace;
424  }
425  runtime->GetThreadList()->ResumeAll();
426
427  if (sampling_pthread != 0U) {
428    CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, NULL), "sampling thread shutdown");
429  }
430}
431
432void Trace::Shutdown() {
433  if (GetMethodTracingMode() != kTracingInactive) {
434    Stop();
435  }
436}
437
438TracingMode Trace::GetMethodTracingMode() {
439  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
440  if (the_trace_ == NULL) {
441    return kTracingInactive;
442  } else if (the_trace_->sampling_enabled_) {
443    return kSampleProfilingActive;
444  } else {
445    return kMethodTracingActive;
446  }
447}
448
449Trace::Trace(File* trace_file, int buffer_size, int flags, bool sampling_enabled)
450    : trace_file_(trace_file), buf_(new uint8_t[buffer_size]()), flags_(flags),
451      sampling_enabled_(sampling_enabled), clock_source_(default_clock_source_),
452      buffer_size_(buffer_size), start_time_(MicroTime()), cur_offset_(0),  overflow_(false) {
453  // Set up the beginning of the trace.
454  uint16_t trace_version = GetTraceVersion(clock_source_);
455  memset(buf_.get(), 0, kTraceHeaderLength);
456  Append4LE(buf_.get(), kTraceMagicValue);
457  Append2LE(buf_.get() + 4, trace_version);
458  Append2LE(buf_.get() + 6, kTraceHeaderLength);
459  Append8LE(buf_.get() + 8, start_time_);
460  if (trace_version >= kTraceVersionDualClock) {
461    uint16_t record_size = GetRecordSize(clock_source_);
462    Append2LE(buf_.get() + 16, record_size);
463  }
464
465  // Update current offset.
466  cur_offset_ = kTraceHeaderLength;
467}
468
469static void DumpBuf(uint8_t* buf, size_t buf_size, ProfilerClockSource clock_source)
470    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
471  uint8_t* ptr = buf + kTraceHeaderLength;
472  uint8_t* end = buf + buf_size;
473
474  while (ptr < end) {
475    uint32_t tmid = ptr[2] | (ptr[3] << 8) | (ptr[4] << 16) | (ptr[5] << 24);
476    mirror::ArtMethod* method = DecodeTraceMethodId(tmid);
477    TraceAction action = DecodeTraceAction(tmid);
478    LOG(INFO) << PrettyMethod(method) << " " << static_cast<int>(action);
479    ptr += GetRecordSize(clock_source);
480  }
481}
482
483void Trace::FinishTracing() {
484  // Compute elapsed time.
485  uint64_t elapsed = MicroTime() - start_time_;
486
487  size_t final_offset = cur_offset_;
488  uint32_t clock_overhead_ns = GetClockOverheadNanoSeconds(this);
489
490  if ((flags_ & kTraceCountAllocs) != 0) {
491    Runtime::Current()->SetStatsEnabled(false);
492  }
493
494  std::set<mirror::ArtMethod*> visited_methods;
495  GetVisitedMethods(final_offset, &visited_methods);
496
497  std::ostringstream os;
498
499  os << StringPrintf("%cversion\n", kTraceTokenChar);
500  os << StringPrintf("%d\n", GetTraceVersion(clock_source_));
501  os << StringPrintf("data-file-overflow=%s\n", overflow_ ? "true" : "false");
502  if (UseThreadCpuClock()) {
503    if (UseWallClock()) {
504      os << StringPrintf("clock=dual\n");
505    } else {
506      os << StringPrintf("clock=thread-cpu\n");
507    }
508  } else {
509    os << StringPrintf("clock=wall\n");
510  }
511  os << StringPrintf("elapsed-time-usec=%" PRIu64 "\n", elapsed);
512  size_t num_records = (final_offset - kTraceHeaderLength) / GetRecordSize(clock_source_);
513  os << StringPrintf("num-method-calls=%zd\n", num_records);
514  os << StringPrintf("clock-call-overhead-nsec=%d\n", clock_overhead_ns);
515  os << StringPrintf("vm=art\n");
516  if ((flags_ & kTraceCountAllocs) != 0) {
517    os << StringPrintf("alloc-count=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_OBJECTS));
518    os << StringPrintf("alloc-size=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_BYTES));
519    os << StringPrintf("gc-count=%d\n", Runtime::Current()->GetStat(KIND_GC_INVOCATIONS));
520  }
521  os << StringPrintf("%cthreads\n", kTraceTokenChar);
522  DumpThreadList(os);
523  os << StringPrintf("%cmethods\n", kTraceTokenChar);
524  DumpMethodList(os, visited_methods);
525  os << StringPrintf("%cend\n", kTraceTokenChar);
526
527  std::string header(os.str());
528  if (trace_file_.get() == NULL) {
529    iovec iov[2];
530    iov[0].iov_base = reinterpret_cast<void*>(const_cast<char*>(header.c_str()));
531    iov[0].iov_len = header.length();
532    iov[1].iov_base = buf_.get();
533    iov[1].iov_len = final_offset;
534    Dbg::DdmSendChunkV(CHUNK_TYPE("MPSE"), iov, 2);
535    const bool kDumpTraceInfo = false;
536    if (kDumpTraceInfo) {
537      LOG(INFO) << "Trace sent:\n" << header;
538      DumpBuf(buf_.get(), final_offset, clock_source_);
539    }
540  } else {
541    if (!trace_file_->WriteFully(header.c_str(), header.length()) ||
542        !trace_file_->WriteFully(buf_.get(), final_offset)) {
543      std::string detail(StringPrintf("Trace data write failed: %s", strerror(errno)));
544      PLOG(ERROR) << detail;
545      ThrowRuntimeException("%s", detail.c_str());
546    }
547  }
548}
549
550void Trace::DexPcMoved(Thread* thread, mirror::Object* this_object,
551                       mirror::ArtMethod* method, uint32_t new_dex_pc) {
552  // We're not recorded to listen to this kind of event, so complain.
553  LOG(ERROR) << "Unexpected dex PC event in tracing " << PrettyMethod(method) << " " << new_dex_pc;
554};
555
556void Trace::MethodEntered(Thread* thread, mirror::Object* this_object,
557                          mirror::ArtMethod* method, uint32_t dex_pc) {
558  uint32_t thread_clock_diff = 0;
559  uint32_t wall_clock_diff = 0;
560  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
561  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodEntered,
562                      thread_clock_diff, wall_clock_diff);
563}
564
565void Trace::MethodExited(Thread* thread, mirror::Object* this_object,
566                         mirror::ArtMethod* method, uint32_t dex_pc,
567                         const JValue& return_value) {
568  UNUSED(return_value);
569  uint32_t thread_clock_diff = 0;
570  uint32_t wall_clock_diff = 0;
571  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
572  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodExited,
573                      thread_clock_diff, wall_clock_diff);
574}
575
576void Trace::MethodUnwind(Thread* thread, mirror::Object* this_object,
577                         mirror::ArtMethod* method, uint32_t dex_pc) {
578  uint32_t thread_clock_diff = 0;
579  uint32_t wall_clock_diff = 0;
580  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
581  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodUnwind,
582                      thread_clock_diff, wall_clock_diff);
583}
584
585void Trace::ExceptionCaught(Thread* thread, const ThrowLocation& throw_location,
586                            mirror::ArtMethod* catch_method, uint32_t catch_dex_pc,
587                            mirror::Throwable* exception_object)
588    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
589  LOG(ERROR) << "Unexpected exception caught event in tracing";
590}
591
592void Trace::ReadClocks(Thread* thread, uint32_t* thread_clock_diff, uint32_t* wall_clock_diff) {
593  if (UseThreadCpuClock()) {
594    uint64_t clock_base = thread->GetTraceClockBase();
595    if (UNLIKELY(clock_base == 0)) {
596      // First event, record the base time in the map.
597      uint64_t time = thread->GetCpuMicroTime();
598      thread->SetTraceClockBase(time);
599    } else {
600      *thread_clock_diff = thread->GetCpuMicroTime() - clock_base;
601    }
602  }
603  if (UseWallClock()) {
604    *wall_clock_diff = MicroTime() - start_time_;
605  }
606}
607
608void Trace::LogMethodTraceEvent(Thread* thread, mirror::ArtMethod* method,
609                                instrumentation::Instrumentation::InstrumentationEvent event,
610                                uint32_t thread_clock_diff, uint32_t wall_clock_diff) {
611  // Advance cur_offset_ atomically.
612  int32_t new_offset;
613  int32_t old_offset;
614  do {
615    old_offset = cur_offset_;
616    new_offset = old_offset + GetRecordSize(clock_source_);
617    if (new_offset > buffer_size_) {
618      overflow_ = true;
619      return;
620    }
621  } while (android_atomic_release_cas(old_offset, new_offset, &cur_offset_) != 0);
622
623  TraceAction action = kTraceMethodEnter;
624  switch (event) {
625    case instrumentation::Instrumentation::kMethodEntered:
626      action = kTraceMethodEnter;
627      break;
628    case instrumentation::Instrumentation::kMethodExited:
629      action = kTraceMethodExit;
630      break;
631    case instrumentation::Instrumentation::kMethodUnwind:
632      action = kTraceUnroll;
633      break;
634    default:
635      UNIMPLEMENTED(FATAL) << "Unexpected event: " << event;
636  }
637
638  uint32_t method_value = EncodeTraceMethodAndAction(method, action);
639
640  // Write data
641  uint8_t* ptr = buf_.get() + old_offset;
642  Append2LE(ptr, thread->GetTid());
643  Append4LE(ptr + 2, method_value);
644  ptr += 6;
645
646  if (UseThreadCpuClock()) {
647    Append4LE(ptr, thread_clock_diff);
648    ptr += 4;
649  }
650  if (UseWallClock()) {
651    Append4LE(ptr, wall_clock_diff);
652  }
653}
654
655void Trace::GetVisitedMethods(size_t buf_size,
656                              std::set<mirror::ArtMethod*>* visited_methods) {
657  uint8_t* ptr = buf_.get() + kTraceHeaderLength;
658  uint8_t* end = buf_.get() + buf_size;
659
660  while (ptr < end) {
661    uint32_t tmid = ptr[2] | (ptr[3] << 8) | (ptr[4] << 16) | (ptr[5] << 24);
662    mirror::ArtMethod* method = DecodeTraceMethodId(tmid);
663    visited_methods->insert(method);
664    ptr += GetRecordSize(clock_source_);
665  }
666}
667
668void Trace::DumpMethodList(std::ostream& os, const std::set<mirror::ArtMethod*>& visited_methods) {
669  MethodHelper mh;
670  for (const auto& method : visited_methods) {
671    mh.ChangeMethod(method);
672    os << StringPrintf("%p\t%s\t%s\t%s\t%s\n", method,
673        PrettyDescriptor(mh.GetDeclaringClassDescriptor()).c_str(), mh.GetName(),
674        mh.GetSignature().ToString().c_str(), mh.GetDeclaringClassSourceFile());
675  }
676}
677
678static void DumpThread(Thread* t, void* arg) {
679  std::ostream& os = *reinterpret_cast<std::ostream*>(arg);
680  std::string name;
681  t->GetThreadName(name);
682  os << t->GetTid() << "\t" << name << "\n";
683}
684
685void Trace::DumpThreadList(std::ostream& os) {
686  Thread* self = Thread::Current();
687  Locks::thread_list_lock_->AssertNotHeld(self);
688  MutexLock mu(self, *Locks::thread_list_lock_);
689  Runtime::Current()->GetThreadList()->ForEach(DumpThread, &os);
690}
691
692}  // namespace art
693