C++ ThreadProfile::addTag方法代码示例

static
void addProfileEntry(ProfileStack *aStack, ThreadProfile &aProfile, int i)
{
  // First entry has tagName 's' (start)
  // Check for magic pointer bit 1 to indicate copy
  const char* sampleLabel = aStack->mStack[i].mLabel;
  if (aStack->mStack[i].isCopyLabel()) {
    // Store the string using 1 or more 'd' (dynamic) tags
    // that will happen to the preceding tag

    aProfile.addTag(ProfileEntry('c', ""));
    // Add one to store the null termination
    size_t strLen = strlen(sampleLabel) + 1;
    for (size_t j = 0; j < strLen;) {
      // Store as many characters in the void* as the platform allows
      char text[sizeof(void*)];
      for (size_t pos = 0; pos < sizeof(void*) && j+pos < strLen; pos++) {
        text[pos] = sampleLabel[j+pos];
      }
      j += sizeof(void*)/sizeof(char);
      // Cast to *((void**) to pass the text data to a void*
      aProfile.addTag(ProfileEntry('d', *((void**)(&text[0]))));
    }
  } else {
    aProfile.addTag(ProfileEntry('c', sampleLabel));
  }
}

void TableTicker::doBacktrace(ThreadProfile &aProfile, TickSample* aSample)
{
#ifndef XP_MACOSX
  uintptr_t thread = GetThreadHandle(platform_data());
  MOZ_ASSERT(thread);
#endif
  void* pc_array[1000];
  PCArray array = {
    pc_array,
    mozilla::ArrayLength(pc_array),
    0
  };

  // Start with the current function.
  StackWalkCallback(aSample->pc, &array);

#ifdef XP_MACOSX
  pthread_t pt = GetProfiledThread(platform_data());
  void *stackEnd = reinterpret_cast<void*>(-1);
  if (pt)
    stackEnd = static_cast<char*>(pthread_get_stackaddr_np(pt));
  nsresult rv = FramePointerStackWalk(StackWalkCallback, 0, &array, reinterpret_cast<void**>(aSample->fp), stackEnd);
#else
  nsresult rv = NS_StackWalk(StackWalkCallback, 0, &array, thread);
#endif
  if (NS_SUCCEEDED(rv)) {
    aProfile.addTag(ProfileEntry('s', "(root)"));

    for (size_t i = array.count; i > 0; --i) {
      aProfile.addTag(ProfileEntry('l', (void*)array.array[i - 1]));
    }
  }
}

void TableTicker::Tick(TickSample* sample)
{
  // Marker(s) come before the sample
  ProfileStack* stack = mPrimaryThreadProfile.GetStack();
  for (int i = 0; stack->getMarker(i) != NULL; i++) {
    mPrimaryThreadProfile.addTag(ProfileEntry('m', stack->getMarker(i)));
  }
  stack->mQueueClearMarker = true;

  bool recordSample = true;
  if (mJankOnly) {
    // if we are on a different event we can discard any temporary samples
    // we've kept around
    if (sLastSampledEventGeneration != sCurrentEventGeneration) {
      // XXX: we also probably want to add an entry to the profile to help
      // distinguish which samples are part of the same event. That, or record
      // the event generation in each sample
      mPrimaryThreadProfile.erase();
    }
    sLastSampledEventGeneration = sCurrentEventGeneration;

    recordSample = false;
    // only record the events when we have a we haven't seen a tracer event for 100ms
    if (!sLastTracerEvent.IsNull()) {
      TimeDuration delta = sample->timestamp - sLastTracerEvent;
      if (delta.ToMilliseconds() > 100.0) {
          recordSample = true;
      }
    }
  }

#if defined(USE_BACKTRACE) || defined(USE_NS_STACKWALK) || defined(USE_LIBUNWIND)
  if (mUseStackWalk) {
    doBacktrace(mPrimaryThreadProfile, sample);
  } else {
    doSampleStackTrace(stack, mPrimaryThreadProfile, sample);
  }
#else
  doSampleStackTrace(stack, mPrimaryThreadProfile, sample);
#endif

  if (recordSample)
    mPrimaryThreadProfile.flush();

  if (!sLastTracerEvent.IsNull() && sample) {
    TimeDuration delta = sample->timestamp - sLastTracerEvent;
    mPrimaryThreadProfile.addTag(ProfileEntry('r', delta.ToMilliseconds()));
  }

  if (sample) {
    TimeDuration delta = sample->timestamp - mStartTime;
    mPrimaryThreadProfile.addTag(ProfileEntry('t', delta.ToMilliseconds()));
  }

  if (sLastFrameNumber != sFrameNumber) {
    mPrimaryThreadProfile.addTag(ProfileEntry('f', sFrameNumber));
    sLastFrameNumber = sFrameNumber;
  }
}

void TableTicker::doBacktrace(ThreadProfile &aProfile, TickSample* aSample)
{
  void *array[100];
  int count = backtrace (array, 100);

  aProfile.addTag(ProfileEntry('s', "(root)"));

  for (int i = 0; i < count; i++) {
    if( (intptr_t)array[i] == -1 ) break;
    aProfile.addTag(ProfileEntry('l', (void*)array[i]));
  }
}

static
void addProfileEntry(volatile StackEntry &entry, ThreadProfile &aProfile,
                     ProfileStack *stack, void *lastpc)
{
  int lineno = -1;

  // First entry has tagName 's' (start)
  // Check for magic pointer bit 1 to indicate copy
  const char* sampleLabel = entry.label();
  if (entry.isCopyLabel()) {
    // Store the string using 1 or more 'd' (dynamic) tags
    // that will happen to the preceding tag

    aProfile.addTag(ProfileEntry('c', ""));
    // Add one to store the null termination
    size_t strLen = strlen(sampleLabel) + 1;
    for (size_t j = 0; j < strLen;) {
      // Store as many characters in the void* as the platform allows
      char text[sizeof(void*)];
      for (size_t pos = 0; pos < sizeof(void*) && j+pos < strLen; pos++) {
        text[pos] = sampleLabel[j+pos];
      }
      j += sizeof(void*)/sizeof(char);
      // Cast to *((void**) to pass the text data to a void*
      aProfile.addTag(ProfileEntry('d', *((void**)(&text[0]))));
    }
    if (entry.js()) {
      if (!entry.pc()) {
        // The JIT only allows the top-most entry to have a NULL pc
        MOZ_ASSERT(&entry == &stack->mStack[stack->stackSize() - 1]);
        // If stack-walking was disabled, then that's just unfortunate
        if (lastpc) {
          jsbytecode *jspc = js::ProfilingGetPC(stack->mRuntime, entry.script(),
                                                lastpc);
          if (jspc) {
            lineno = JS_PCToLineNumber(NULL, entry.script(), jspc);
          }
        }
      } else {
        lineno = JS_PCToLineNumber(NULL, entry.script(), entry.pc());
      }
    } else {
      lineno = entry.line();
    }
  } else {
    aProfile.addTag(ProfileEntry('c', sampleLabel));
    lineno = entry.line();
  }
  if (lineno != -1) {
    aProfile.addTag(ProfileEntry('n', lineno));
  }
}

static
void doSampleStackTrace(ThreadProfile &aProfile, TickSample *aSample, bool aAddLeafAddresses)
{
  NativeStack nativeStack = { nullptr, nullptr, 0, 0 };
  mergeStacksIntoProfile(aProfile, aSample, nativeStack);

#ifdef ENABLE_SPS_LEAF_DATA
  if (aSample && aAddLeafAddresses) {
    aProfile.addTag(ProfileEntry('l', (void*)aSample->pc));
#ifdef ENABLE_ARM_LR_SAVING
    aProfile.addTag(ProfileEntry('L', (void*)aSample->lr));
#endif
  }
#endif
}

static
void doSampleStackTrace(ProfileStack *aStack, ThreadProfile &aProfile, TickSample *sample)
{
  // Sample
  // 's' tag denotes the start of a sample block
  // followed by 0 or more 'c' tags.
  aProfile.addTag(ProfileEntry('s', "(root)"));
  for (mozilla::sig_safe_t i = 0;
       i < aStack->mStackPointer && i < mozilla::ArrayLength(aStack->mStack);
       i++) {
    addProfileEntry(aStack, aProfile, i);
  }
#ifdef ENABLE_SPS_LEAF_DATA
  if (sample) {
    aProfile.addTag(ProfileEntry('l', (void*)sample->pc));
#ifdef ENABLE_ARM_LR_SAVING
    aProfile.addTag(ProfileEntry('L', (void*)sample->lr));
#endif
  }
#endif
}

static
void doSampleStackTrace(ProfileStack *aStack, ThreadProfile &aProfile, TickSample *sample)
{
  // Sample
  // 's' tag denotes the start of a sample block
  // followed by 0 or more 'c' tags.
  aProfile.addTag(ProfileEntry('s', "(root)"));
  for (mozilla::sig_safe_t i = 0; i < aStack->mStackPointer; i++) {
    // First entry has tagName 's' (start)
    // Check for magic pointer bit 1 to indicate copy
    const char* sampleLabel = aStack->mStack[i].mLabel;
    if (aStack->mStack[i].isCopyLabel()) {
      // Store the string using 1 or more 'd' (dynamic) tags
      // that will happen to the preceding tag

      aProfile.addTag(ProfileEntry('c', ""));
      // Add one to store the null termination
      size_t strLen = strlen(sampleLabel) + 1;
      for (size_t j = 0; j < strLen;) {
        // Store as many characters in the void* as the platform allows
        char text[sizeof(void*)];
        for (size_t pos = 0; pos < sizeof(void*) && j+pos < strLen; pos++) {
          text[pos] = sampleLabel[j+pos];
        }
        j += sizeof(void*);
        // Take '*((void**)(&text[0]))' to pass the char[] as a single void*
        aProfile.addTag(ProfileEntry('d', *((void**)(&text[0]))));
      }
    } else {
      aProfile.addTag(ProfileEntry('c', sampleLabel));
    }
  }
#ifdef ENABLE_SPS_LEAF_DATA
  if (sample) {
    aProfile.addTag(ProfileEntry('l', (void*)sample->pc));
  }
#endif
}

static
void mergeStacksIntoProfile(ThreadProfile& aProfile, TickSample* aSample, NativeStack& aNativeStack)
{
  PseudoStack* pseudoStack = aProfile.GetPseudoStack();
  volatile StackEntry *pseudoFrames = pseudoStack->mStack;
  uint32_t pseudoCount = pseudoStack->stackSize();

  // Make a copy of the JS stack into a JSFrame array. This is necessary since,
  // like the native stack, the JS stack is iterated youngest-to-oldest and we
  // need to iterate oldest-to-youngest when adding entries to aProfile.

  // Synchronous sampling reports an invalid buffer generation to
  // ProfilingFrameIterator to avoid incorrectly resetting the generation of
  // sampled JIT entries inside the JS engine. See note below concerning 'J'
  // entries.
  uint32_t startBufferGen;
  if (aSample->isSamplingCurrentThread) {
    startBufferGen = UINT32_MAX;
  } else {
    startBufferGen = aProfile.bufferGeneration();
  }
  uint32_t jsCount = 0;
#ifndef SPS_STANDALONE
  JS::ProfilingFrameIterator::Frame jsFrames[1000];
  // Only walk jit stack if profiling frame iterator is turned on.
  if (pseudoStack->mRuntime && JS::IsProfilingEnabledForRuntime(pseudoStack->mRuntime)) {
    AutoWalkJSStack autoWalkJSStack;
    const uint32_t maxFrames = mozilla::ArrayLength(jsFrames);

    if (aSample && autoWalkJSStack.walkAllowed) {
      JS::ProfilingFrameIterator::RegisterState registerState;
      registerState.pc = aSample->pc;
      registerState.sp = aSample->sp;
#ifdef ENABLE_ARM_LR_SAVING
      registerState.lr = aSample->lr;
#endif

      JS::ProfilingFrameIterator jsIter(pseudoStack->mRuntime,
                                        registerState,
                                        startBufferGen);
      for (; jsCount < maxFrames && !jsIter.done(); ++jsIter) {
        // See note below regarding 'J' entries.
        if (aSample->isSamplingCurrentThread || jsIter.isAsmJS()) {
          uint32_t extracted = jsIter.extractStack(jsFrames, jsCount, maxFrames);
          jsCount += extracted;
          if (jsCount == maxFrames)
            break;
        } else {
          mozilla::Maybe<JS::ProfilingFrameIterator::Frame> frame =
            jsIter.getPhysicalFrameWithoutLabel();
          if (frame.isSome())
            jsFrames[jsCount++] = frame.value();
        }
      }
    }
  }
#endif

  // Start the sample with a root entry.
  aProfile.addTag(ProfileEntry('s', "(root)"));

  // While the pseudo-stack array is ordered oldest-to-youngest, the JS and
  // native arrays are ordered youngest-to-oldest. We must add frames to
  // aProfile oldest-to-youngest. Thus, iterate over the pseudo-stack forwards
  // and JS and native arrays backwards. Note: this means the terminating
  // condition jsIndex and nativeIndex is being < 0.
  uint32_t pseudoIndex = 0;
  int32_t jsIndex = jsCount - 1;
  int32_t nativeIndex = aNativeStack.count - 1;

  uint8_t *lastPseudoCppStackAddr = nullptr;

  // Iterate as long as there is at least one frame remaining.
  while (pseudoIndex != pseudoCount || jsIndex >= 0 || nativeIndex >= 0) {
    // There are 1 to 3 frames available. Find and add the oldest.

    uint8_t *pseudoStackAddr = nullptr;
    uint8_t *jsStackAddr = nullptr;
    uint8_t *nativeStackAddr = nullptr;

    if (pseudoIndex != pseudoCount) {
      volatile StackEntry &pseudoFrame = pseudoFrames[pseudoIndex];

      if (pseudoFrame.isCpp())
        lastPseudoCppStackAddr = (uint8_t *) pseudoFrame.stackAddress();

#ifndef SPS_STANDALONE
      // Skip any pseudo-stack JS frames which are marked isOSR
      // Pseudostack frames are marked isOSR when the JS interpreter
      // enters a jit frame on a loop edge (via on-stack-replacement,
      // or OSR).  To avoid both the pseudoframe and jit frame being
      // recorded (and showing up twice), the interpreter marks the
      // interpreter pseudostack entry with the OSR flag to ensure that
      // it doesn't get counted.
      if (pseudoFrame.isJs() && pseudoFrame.isOSR()) {
          pseudoIndex++;
          continue;
      }
#endif

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