trace.cc revision 9433ec60b325b708b9fa87e699ab4a6565741494 
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 "os.h"
34#include "scoped_thread_state_change.h"
35#include "ScopedLocalRef.h"
36#include "thread.h"
37#include "thread_list.h"
38#if !defined(ART_USE_PORTABLE_COMPILER)
39#include "entrypoints/quick/quick_entrypoints.h"
40#endif
41
42namespace art {
43
44// File format:
45//     header
46//     record 0
47//     record 1
48//     ...
49//
50// Header format:
51//     u4  magic ('SLOW')
52//     u2  version
53//     u2  offset to data
54//     u8  start date/time in usec
55//     u2  record size in bytes (version >= 2 only)
56//     ... padding to 32 bytes
57//
58// Record format v1:
59//     u1  thread ID
60//     u4  method ID | method action
61//     u4  time delta since start, in usec
62//
63// Record format v2:
64//     u2  thread ID
65//     u4  method ID | method action
66//     u4  time delta since start, in usec
67//
68// Record format v3:
69//     u2  thread ID
70//     u4  method ID | method action
71//     u4  time delta since start, in usec
72//     u4  wall time since start, in usec (when clock == "dual" only)
73//
74// 32 bits of microseconds is 70 minutes.
75//
76// All values are stored in little-endian order.
77
78enum TraceAction {
79    kTraceMethodEnter = 0x00,       // method entry
80    kTraceMethodExit = 0x01,        // method exit
81    kTraceUnroll = 0x02,            // method exited by exception unrolling
82    // 0x03 currently unused
83    kTraceMethodActionMask = 0x03,  // two bits
84};
85
86class BuildStackTraceVisitor : public StackVisitor {
87 public:
88  explicit BuildStackTraceVisitor(Thread* thread) : StackVisitor(thread, NULL),
89      method_trace_(Trace::AllocStackTrace()) {}
90
91  bool VisitFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
92    mirror::ArtMethod* m = GetMethod();
93    // Ignore runtime frames (in particular callee save).
94    if (!m->IsRuntimeMethod()) {
95      method_trace_->push_back(m);
96    }
97    return true;
98  }
99
100  // Returns a stack trace where the topmost frame corresponds with the first element of the vector.
101  std::vector<mirror::ArtMethod*>* GetStackTrace() const {
102    return method_trace_;
103  }
104
105 private:
106  std::vector<mirror::ArtMethod*>* const method_trace_;
107};
108
109static const char     kTraceTokenChar             = '*';
110static const uint16_t kTraceHeaderLength          = 32;
111static const uint32_t kTraceMagicValue            = 0x574f4c53;
112static const uint16_t kTraceVersionSingleClock    = 2;
113static const uint16_t kTraceVersionDualClock      = 3;
114static const uint16_t kTraceRecordSizeSingleClock = 10;  // using v2
115static const uint16_t kTraceRecordSizeDualClock   = 14;  // using v3 with two timestamps
116
117TraceClockSource Trace::default_clock_source_ = kDefaultTraceClockSource;
118
119Trace* volatile Trace::the_trace_ = NULL;
120pthread_t Trace::sampling_pthread_ = 0U;
121std::unique_ptr<std::vector<mirror::ArtMethod*>> Trace::temp_stack_trace_;
122
123static mirror::ArtMethod* DecodeTraceMethodId(uint32_t tmid) {
124  return reinterpret_cast<mirror::ArtMethod*>(tmid & ~kTraceMethodActionMask);
125}
126
127static TraceAction DecodeTraceAction(uint32_t tmid) {
128  return static_cast<TraceAction>(tmid & kTraceMethodActionMask);
129}
130
131static uint32_t EncodeTraceMethodAndAction(mirror::ArtMethod* method,
132                                           TraceAction action) {
133  uint32_t tmid = PointerToLowMemUInt32(method) | action;
134  DCHECK_EQ(method, DecodeTraceMethodId(tmid));
135  return tmid;
136}
137
138std::vector<mirror::ArtMethod*>* Trace::AllocStackTrace() {
139  if (temp_stack_trace_.get() != NULL) {
140    return temp_stack_trace_.release();
141  } else {
142    return new std::vector<mirror::ArtMethod*>();
143  }
144}
145
146void Trace::FreeStackTrace(std::vector<mirror::ArtMethod*>* stack_trace) {
147  stack_trace->clear();
148  temp_stack_trace_.reset(stack_trace);
149}
150
151void Trace::SetDefaultClockSource(TraceClockSource clock_source) {
152#if defined(HAVE_POSIX_CLOCKS)
153  default_clock_source_ = clock_source;
154#else
155  if (clock_source != kTraceClockSourceWall) {
156    LOG(WARNING) << "Ignoring tracing request to use CPU time.";
157  }
158#endif
159}
160
161static uint16_t GetTraceVersion(TraceClockSource clock_source) {
162  return (clock_source == kTraceClockSourceDual) ? kTraceVersionDualClock
163                                                    : kTraceVersionSingleClock;
164}
165
166static uint16_t GetRecordSize(TraceClockSource clock_source) {
167  return (clock_source == kTraceClockSourceDual) ? kTraceRecordSizeDualClock
168                                                    : kTraceRecordSizeSingleClock;
169}
170
171bool Trace::UseThreadCpuClock() {
172  return (clock_source_ == kTraceClockSourceThreadCpu) ||
173      (clock_source_ == kTraceClockSourceDual);
174}
175
176bool Trace::UseWallClock() {
177  return (clock_source_ == kTraceClockSourceWall) ||
178      (clock_source_ == kTraceClockSourceDual);
179}
180
181void Trace::MeasureClockOverhead() {
182  if (UseThreadCpuClock()) {
183    Thread::Current()->GetCpuMicroTime();
184  }
185  if (UseWallClock()) {
186    MicroTime();
187  }
188}
189
190// Compute an average time taken to measure clocks.
191uint32_t Trace::GetClockOverheadNanoSeconds() {
192  Thread* self = Thread::Current();
193  uint64_t start = self->GetCpuMicroTime();
194
195  for (int i = 4000; i > 0; i--) {
196    MeasureClockOverhead();
197    MeasureClockOverhead();
198    MeasureClockOverhead();
199    MeasureClockOverhead();
200    MeasureClockOverhead();
201    MeasureClockOverhead();
202    MeasureClockOverhead();
203    MeasureClockOverhead();
204  }
205
206  uint64_t elapsed_us = self->GetCpuMicroTime() - start;
207  return static_cast<uint32_t>(elapsed_us / 32);
208}
209
210// TODO: put this somewhere with the big-endian equivalent used by JDWP.
211static void Append2LE(uint8_t* buf, uint16_t val) {
212  *buf++ = static_cast<uint8_t>(val);
213  *buf++ = static_cast<uint8_t>(val >> 8);
214}
215
216// TODO: put this somewhere with the big-endian equivalent used by JDWP.
217static void Append4LE(uint8_t* buf, uint32_t val) {
218  *buf++ = static_cast<uint8_t>(val);
219  *buf++ = static_cast<uint8_t>(val >> 8);
220  *buf++ = static_cast<uint8_t>(val >> 16);
221  *buf++ = static_cast<uint8_t>(val >> 24);
222}
223
224// TODO: put this somewhere with the big-endian equivalent used by JDWP.
225static void Append8LE(uint8_t* buf, uint64_t val) {
226  *buf++ = static_cast<uint8_t>(val);
227  *buf++ = static_cast<uint8_t>(val >> 8);
228  *buf++ = static_cast<uint8_t>(val >> 16);
229  *buf++ = static_cast<uint8_t>(val >> 24);
230  *buf++ = static_cast<uint8_t>(val >> 32);
231  *buf++ = static_cast<uint8_t>(val >> 40);
232  *buf++ = static_cast<uint8_t>(val >> 48);
233  *buf++ = static_cast<uint8_t>(val >> 56);
234}
235
236static void GetSample(Thread* thread, void* arg) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
237  BuildStackTraceVisitor build_trace_visitor(thread);
238  build_trace_visitor.WalkStack();
239  std::vector<mirror::ArtMethod*>* stack_trace = build_trace_visitor.GetStackTrace();
240  Trace* the_trace = reinterpret_cast<Trace*>(arg);
241  the_trace->CompareAndUpdateStackTrace(thread, stack_trace);
242}
243
244static void ClearThreadStackTraceAndClockBase(Thread* thread, void* arg) {
245  thread->SetTraceClockBase(0);
246  std::vector<mirror::ArtMethod*>* stack_trace = thread->GetStackTraceSample();
247  thread->SetStackTraceSample(NULL);
248  delete stack_trace;
249}
250
251void Trace::CompareAndUpdateStackTrace(Thread* thread,
252                                       std::vector<mirror::ArtMethod*>* stack_trace) {
253  CHECK_EQ(pthread_self(), sampling_pthread_);
254  std::vector<mirror::ArtMethod*>* old_stack_trace = thread->GetStackTraceSample();
255  // Update the thread's stack trace sample.
256  thread->SetStackTraceSample(stack_trace);
257  // Read timer clocks to use for all events in this trace.
258  uint32_t thread_clock_diff = 0;
259  uint32_t wall_clock_diff = 0;
260  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
261  if (old_stack_trace == NULL) {
262    // If there's no previous stack trace sample for this thread, log an entry event for all
263    // methods in the trace.
264    for (std::vector<mirror::ArtMethod*>::reverse_iterator rit = stack_trace->rbegin();
265         rit != stack_trace->rend(); ++rit) {
266      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
267                          thread_clock_diff, wall_clock_diff);
268    }
269  } else {
270    // If there's a previous stack trace for this thread, diff the traces and emit entry and exit
271    // events accordingly.
272    std::vector<mirror::ArtMethod*>::reverse_iterator old_rit = old_stack_trace->rbegin();
273    std::vector<mirror::ArtMethod*>::reverse_iterator rit = stack_trace->rbegin();
274    // Iterate bottom-up over both traces until there's a difference between them.
275    while (old_rit != old_stack_trace->rend() && rit != stack_trace->rend() && *old_rit == *rit) {
276      old_rit++;
277      rit++;
278    }
279    // Iterate top-down over the old trace until the point where they differ, emitting exit events.
280    for (std::vector<mirror::ArtMethod*>::iterator old_it = old_stack_trace->begin();
281         old_it != old_rit.base(); ++old_it) {
282      LogMethodTraceEvent(thread, *old_it, instrumentation::Instrumentation::kMethodExited,
283                          thread_clock_diff, wall_clock_diff);
284    }
285    // Iterate bottom-up over the new trace from the point where they differ, emitting entry events.
286    for (; rit != stack_trace->rend(); ++rit) {
287      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
288                          thread_clock_diff, wall_clock_diff);
289    }
290    FreeStackTrace(old_stack_trace);
291  }
292}
293
294void* Trace::RunSamplingThread(void* arg) {
295  Runtime* runtime = Runtime::Current();
296  intptr_t interval_us = reinterpret_cast<intptr_t>(arg);
297  CHECK_GE(interval_us, 0);
298  CHECK(runtime->AttachCurrentThread("Sampling Profiler", true, runtime->GetSystemThreadGroup(),
299                                     !runtime->IsCompiler()));
300
301  while (true) {
302    usleep(interval_us);
303    ATRACE_BEGIN("Profile sampling");
304    Thread* self = Thread::Current();
305    Trace* the_trace;
306    {
307      MutexLock mu(self, *Locks::trace_lock_);
308      the_trace = the_trace_;
309      if (the_trace == NULL) {
310        break;
311      }
312    }
313
314    runtime->GetThreadList()->SuspendAll();
315    {
316      MutexLock mu(self, *Locks::thread_list_lock_);
317      runtime->GetThreadList()->ForEach(GetSample, the_trace);
318    }
319    runtime->GetThreadList()->ResumeAll();
320    ATRACE_END();
321  }
322
323  runtime->DetachCurrentThread();
324  return NULL;
325}
326
327void Trace::Start(const char* trace_filename, int trace_fd, int buffer_size, int flags,
328                  bool direct_to_ddms, bool sampling_enabled, int interval_us) {
329  Thread* self = Thread::Current();
330  {
331    MutexLock mu(self, *Locks::trace_lock_);
332    if (the_trace_ != NULL) {
333      LOG(ERROR) << "Trace already in progress, ignoring this request";
334      return;
335    }
336  }
337
338  // Check interval if sampling is enabled
339  if (sampling_enabled && interval_us <= 0) {
340    LOG(ERROR) << "Invalid sampling interval: " << interval_us;
341    ScopedObjectAccess soa(self);
342    ThrowRuntimeException("Invalid sampling interval: %d", interval_us);
343    return;
344  }
345
346  // Open trace file if not going directly to ddms.
347  std::unique_ptr<File> trace_file;
348  if (!direct_to_ddms) {
349    if (trace_fd < 0) {
350      trace_file.reset(OS::CreateEmptyFile(trace_filename));
351    } else {
352      trace_file.reset(new File(trace_fd, "tracefile"));
353      trace_file->DisableAutoClose();
354    }
355    if (trace_file.get() == NULL) {
356      PLOG(ERROR) << "Unable to open trace file '" << trace_filename << "'";
357      ScopedObjectAccess soa(self);
358      ThrowRuntimeException("Unable to open trace file '%s'", trace_filename);
359      return;
360    }
361  }
362
363  Runtime* runtime = Runtime::Current();
364
365  // Enable count of allocs if specified in the flags.
366  bool enable_stats = false;
367
368  runtime->GetThreadList()->SuspendAll();
369
370  // Create Trace object.
371  {
372    MutexLock mu(self, *Locks::trace_lock_);
373    if (the_trace_ != NULL) {
374      LOG(ERROR) << "Trace already in progress, ignoring this request";
375    } else {
376      enable_stats = (flags && kTraceCountAllocs) != 0;
377      the_trace_ = new Trace(trace_file.release(), buffer_size, flags, sampling_enabled);
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
392  runtime->GetThreadList()->ResumeAll();
393
394  // Can't call this when holding the mutator lock.
395  if (enable_stats) {
396    runtime->SetStatsEnabled(true);
397  }
398}
399
400void Trace::Stop() {
401  bool stop_alloc_counting = false;
402  Runtime* runtime = Runtime::Current();
403  runtime->GetThreadList()->SuspendAll();
404  Trace* the_trace = NULL;
405  pthread_t sampling_pthread = 0U;
406  {
407    MutexLock mu(Thread::Current(), *Locks::trace_lock_);
408    if (the_trace_ == NULL) {
409      LOG(ERROR) << "Trace stop requested, but no trace currently running";
410    } else {
411      the_trace = the_trace_;
412      the_trace_ = NULL;
413      sampling_pthread = sampling_pthread_;
414    }
415  }
416  if (the_trace != NULL) {
417    stop_alloc_counting = (the_trace->flags_ & kTraceCountAllocs) != 0;
418    the_trace->FinishTracing();
419
420    if (the_trace->sampling_enabled_) {
421      MutexLock mu(Thread::Current(), *Locks::thread_list_lock_);
422      runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, NULL);
423    } else {
424      runtime->GetInstrumentation()->DisableMethodTracing();
425      runtime->GetInstrumentation()->RemoveListener(the_trace,
426                                                    instrumentation::Instrumentation::kMethodEntered |
427                                                    instrumentation::Instrumentation::kMethodExited |
428                                                    instrumentation::Instrumentation::kMethodUnwind);
429    }
430    if (the_trace->trace_file_.get() != nullptr) {
431      // Do not try to erase, so flush and close explicitly.
432      if (the_trace->trace_file_->Flush() != 0) {
433        PLOG(ERROR) << "Could not flush trace file.";
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
443  if (stop_alloc_counting) {
444    // Can be racy since SetStatsEnabled is not guarded by any locks.
445    Runtime::Current()->SetStatsEnabled(false);
446  }
447
448  if (sampling_pthread != 0U) {
449    CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, NULL), "sampling thread shutdown");
450    sampling_pthread_ = 0U;
451  }
452}
453
454void Trace::Shutdown() {
455  if (GetMethodTracingMode() != kTracingInactive) {
456    Stop();
457  }
458}
459
460TracingMode Trace::GetMethodTracingMode() {
461  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
462  if (the_trace_ == NULL) {
463    return kTracingInactive;
464  } else if (the_trace_->sampling_enabled_) {
465    return kSampleProfilingActive;
466  } else {
467    return kMethodTracingActive;
468  }
469}
470
471Trace::Trace(File* trace_file, int buffer_size, int flags, bool sampling_enabled)
472    : trace_file_(trace_file), buf_(new uint8_t[buffer_size]()), flags_(flags),
473      sampling_enabled_(sampling_enabled), clock_source_(default_clock_source_),
474      buffer_size_(buffer_size), start_time_(MicroTime()),
475      clock_overhead_ns_(GetClockOverheadNanoSeconds()), cur_offset_(0), overflow_(false) {
476  // Set up the beginning of the trace.
477  uint16_t trace_version = GetTraceVersion(clock_source_);
478  memset(buf_.get(), 0, kTraceHeaderLength);
479  Append4LE(buf_.get(), kTraceMagicValue);
480  Append2LE(buf_.get() + 4, trace_version);
481  Append2LE(buf_.get() + 6, kTraceHeaderLength);
482  Append8LE(buf_.get() + 8, start_time_);
483  if (trace_version >= kTraceVersionDualClock) {
484    uint16_t record_size = GetRecordSize(clock_source_);
485    Append2LE(buf_.get() + 16, record_size);
486  }
487
488  // Update current offset.
489  cur_offset_.StoreRelaxed(kTraceHeaderLength);
490}
491
492static void DumpBuf(uint8_t* buf, size_t buf_size, TraceClockSource clock_source)
493    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
494  uint8_t* ptr = buf + kTraceHeaderLength;
495  uint8_t* end = buf + buf_size;
496
497  while (ptr < end) {
498    uint32_t tmid = ptr[2] | (ptr[3] << 8) | (ptr[4] << 16) | (ptr[5] << 24);
499    mirror::ArtMethod* method = DecodeTraceMethodId(tmid);
500    TraceAction action = DecodeTraceAction(tmid);
501    LOG(INFO) << PrettyMethod(method) << " " << static_cast<int>(action);
502    ptr += GetRecordSize(clock_source);
503  }
504}
505
506void Trace::FinishTracing() {
507  // Compute elapsed time.
508  uint64_t elapsed = MicroTime() - start_time_;
509
510  size_t final_offset = cur_offset_.LoadRelaxed();
511
512  std::set<mirror::ArtMethod*> visited_methods;
513  GetVisitedMethods(final_offset, &visited_methods);
514
515  std::ostringstream os;
516
517  os << StringPrintf("%cversion\n", kTraceTokenChar);
518  os << StringPrintf("%d\n", GetTraceVersion(clock_source_));
519  os << StringPrintf("data-file-overflow=%s\n", overflow_ ? "true" : "false");
520  if (UseThreadCpuClock()) {
521    if (UseWallClock()) {
522      os << StringPrintf("clock=dual\n");
523    } else {
524      os << StringPrintf("clock=thread-cpu\n");
525    }
526  } else {
527    os << StringPrintf("clock=wall\n");
528  }
529  os << StringPrintf("elapsed-time-usec=%" PRIu64 "\n", elapsed);
530  size_t num_records = (final_offset - kTraceHeaderLength) / GetRecordSize(clock_source_);
531  os << StringPrintf("num-method-calls=%zd\n", num_records);
532  os << StringPrintf("clock-call-overhead-nsec=%d\n", clock_overhead_ns_);
533  os << StringPrintf("vm=art\n");
534  if ((flags_ & kTraceCountAllocs) != 0) {
535    os << StringPrintf("alloc-count=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_OBJECTS));
536    os << StringPrintf("alloc-size=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_BYTES));
537    os << StringPrintf("gc-count=%d\n", Runtime::Current()->GetStat(KIND_GC_INVOCATIONS));
538  }
539  os << StringPrintf("%cthreads\n", kTraceTokenChar);
540  DumpThreadList(os);
541  os << StringPrintf("%cmethods\n", kTraceTokenChar);
542  DumpMethodList(os, visited_methods);
543  os << StringPrintf("%cend\n", kTraceTokenChar);
544
545  std::string header(os.str());
546  if (trace_file_.get() == NULL) {
547    iovec iov[2];
548    iov[0].iov_base = reinterpret_cast<void*>(const_cast<char*>(header.c_str()));
549    iov[0].iov_len = header.length();
550    iov[1].iov_base = buf_.get();
551    iov[1].iov_len = final_offset;
552    Dbg::DdmSendChunkV(CHUNK_TYPE("MPSE"), iov, 2);
553    const bool kDumpTraceInfo = false;
554    if (kDumpTraceInfo) {
555      LOG(INFO) << "Trace sent:\n" << header;
556      DumpBuf(buf_.get(), final_offset, clock_source_);
557    }
558  } else {
559    if (!trace_file_->WriteFully(header.c_str(), header.length()) ||
560        !trace_file_->WriteFully(buf_.get(), final_offset)) {
561      std::string detail(StringPrintf("Trace data write failed: %s", strerror(errno)));
562      PLOG(ERROR) << detail;
563      ThrowRuntimeException("%s", detail.c_str());
564    }
565  }
566}
567
568void Trace::DexPcMoved(Thread* thread, mirror::Object* this_object,
569                       mirror::ArtMethod* method, uint32_t new_dex_pc) {
570  // We're not recorded to listen to this kind of event, so complain.
571  LOG(ERROR) << "Unexpected dex PC event in tracing " << PrettyMethod(method) << " " << new_dex_pc;
572};
573
574void Trace::FieldRead(Thread* /*thread*/, mirror::Object* this_object,
575                       mirror::ArtMethod* method, uint32_t dex_pc, mirror::ArtField* field)
576    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
577  // We're not recorded to listen to this kind of event, so complain.
578  LOG(ERROR) << "Unexpected field read event in tracing " << PrettyMethod(method) << " " << dex_pc;
579}
580
581void Trace::FieldWritten(Thread* /*thread*/, mirror::Object* this_object,
582                          mirror::ArtMethod* method, uint32_t dex_pc, mirror::ArtField* field,
583                          const JValue& field_value)
584    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
585  // We're not recorded to listen to this kind of event, so complain.
586  LOG(ERROR) << "Unexpected field write event in tracing " << PrettyMethod(method) << " " << dex_pc;
587}
588
589void Trace::MethodEntered(Thread* thread, mirror::Object* this_object,
590                          mirror::ArtMethod* method, uint32_t dex_pc) {
591  uint32_t thread_clock_diff = 0;
592  uint32_t wall_clock_diff = 0;
593  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
594  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodEntered,
595                      thread_clock_diff, wall_clock_diff);
596}
597
598void Trace::MethodExited(Thread* thread, mirror::Object* this_object,
599                         mirror::ArtMethod* method, uint32_t dex_pc,
600                         const JValue& return_value) {
601  UNUSED(return_value);
602  uint32_t thread_clock_diff = 0;
603  uint32_t wall_clock_diff = 0;
604  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
605  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodExited,
606                      thread_clock_diff, wall_clock_diff);
607}
608
609void Trace::MethodUnwind(Thread* thread, mirror::Object* this_object,
610                         mirror::ArtMethod* method, uint32_t dex_pc) {
611  uint32_t thread_clock_diff = 0;
612  uint32_t wall_clock_diff = 0;
613  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
614  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodUnwind,
615                      thread_clock_diff, wall_clock_diff);
616}
617
618void Trace::ExceptionCaught(Thread* thread, const ThrowLocation& throw_location,
619                            mirror::ArtMethod* catch_method, uint32_t catch_dex_pc,
620                            mirror::Throwable* exception_object)
621    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
622  LOG(ERROR) << "Unexpected exception caught event in tracing";
623}
624
625void Trace::ReadClocks(Thread* thread, uint32_t* thread_clock_diff, uint32_t* wall_clock_diff) {
626  if (UseThreadCpuClock()) {
627    uint64_t clock_base = thread->GetTraceClockBase();
628    if (UNLIKELY(clock_base == 0)) {
629      // First event, record the base time in the map.
630      uint64_t time = thread->GetCpuMicroTime();
631      thread->SetTraceClockBase(time);
632    } else {
633      *thread_clock_diff = thread->GetCpuMicroTime() - clock_base;
634    }
635  }
636  if (UseWallClock()) {
637    *wall_clock_diff = MicroTime() - start_time_;
638  }
639}
640
641void Trace::LogMethodTraceEvent(Thread* thread, mirror::ArtMethod* method,
642                                instrumentation::Instrumentation::InstrumentationEvent event,
643                                uint32_t thread_clock_diff, uint32_t wall_clock_diff) {
644  // Advance cur_offset_ atomically.
645  int32_t new_offset;
646  int32_t old_offset;
647  do {
648    old_offset = cur_offset_.LoadRelaxed();
649    new_offset = old_offset + GetRecordSize(clock_source_);
650    if (new_offset > buffer_size_) {
651      overflow_ = true;
652      return;
653    }
654  } while (!cur_offset_.CompareExchangeWeakSequentiallyConsistent(old_offset, new_offset));
655
656  TraceAction action = kTraceMethodEnter;
657  switch (event) {
658    case instrumentation::Instrumentation::kMethodEntered:
659      action = kTraceMethodEnter;
660      break;
661    case instrumentation::Instrumentation::kMethodExited:
662      action = kTraceMethodExit;
663      break;
664    case instrumentation::Instrumentation::kMethodUnwind:
665      action = kTraceUnroll;
666      break;
667    default:
668      UNIMPLEMENTED(FATAL) << "Unexpected event: " << event;
669  }
670
671  uint32_t method_value = EncodeTraceMethodAndAction(method, action);
672
673  // Write data
674  uint8_t* ptr = buf_.get() + old_offset;
675  Append2LE(ptr, thread->GetTid());
676  Append4LE(ptr + 2, method_value);
677  ptr += 6;
678
679  if (UseThreadCpuClock()) {
680    Append4LE(ptr, thread_clock_diff);
681    ptr += 4;
682  }
683  if (UseWallClock()) {
684    Append4LE(ptr, wall_clock_diff);
685  }
686}
687
688void Trace::GetVisitedMethods(size_t buf_size,
689                              std::set<mirror::ArtMethod*>* visited_methods) {
690  uint8_t* ptr = buf_.get() + kTraceHeaderLength;
691  uint8_t* end = buf_.get() + buf_size;
692
693  while (ptr < end) {
694    uint32_t tmid = ptr[2] | (ptr[3] << 8) | (ptr[4] << 16) | (ptr[5] << 24);
695    mirror::ArtMethod* method = DecodeTraceMethodId(tmid);
696    visited_methods->insert(method);
697    ptr += GetRecordSize(clock_source_);
698  }
699}
700
701void Trace::DumpMethodList(std::ostream& os, const std::set<mirror::ArtMethod*>& visited_methods) {
702  for (const auto& method : visited_methods) {
703    os << StringPrintf("%p\t%s\t%s\t%s\t%s\n", method,
704        PrettyDescriptor(method->GetDeclaringClassDescriptor()).c_str(), method->GetName(),
705        method->GetSignature().ToString().c_str(), method->GetDeclaringClassSourceFile());
706  }
707}
708
709static void DumpThread(Thread* t, void* arg) {
710  std::ostream& os = *reinterpret_cast<std::ostream*>(arg);
711  std::string name;
712  t->GetThreadName(name);
713  os << t->GetTid() << "\t" << name << "\n";
714}
715
716void Trace::DumpThreadList(std::ostream& os) {
717  Thread* self = Thread::Current();
718  for (auto it : exited_threads_) {
719    os << it.first << "\t" << it.second << "\n";
720  }
721  Locks::thread_list_lock_->AssertNotHeld(self);
722  MutexLock mu(self, *Locks::thread_list_lock_);
723  Runtime::Current()->GetThreadList()->ForEach(DumpThread, &os);
724}
725
726void Trace::StoreExitingThreadInfo(Thread* thread) {
727  MutexLock mu(thread, *Locks::trace_lock_);
728  if (the_trace_ != nullptr) {
729    std::string name;
730    thread->GetThreadName(name);
731    the_trace_->exited_threads_.Put(thread->GetTid(), name);
732  }
733}
734
735}  // namespace art
736