dart::ProfilerNativeStackWalker Class Reference

Inheritance diagram for dart::ProfilerNativeStackWalker:

Public Member Functions
	ProfilerNativeStackWalker (ProfilerCounters *counters, Dart_Port port_id, Sample *sample, SampleBuffer *sample_buffer, uword stack_lower, uword stack_upper, uword pc, uword fp, uword sp, intptr_t skip_count=0)
void	walk ()
Public Member Functions inherited from dart::ProfilerStackWalker
	ProfilerStackWalker (Dart_Port port_id, Sample *head_sample, SampleBuffer *sample_buffer, intptr_t skip_count=0)
bool	Append (uword pc, uword fp)
Public Member Functions inherited from dart::ValueObject
	ValueObject ()
	~ValueObject ()

Additional Inherited Members
Protected Attributes inherited from dart::ProfilerStackWalker
Dart_Port	port_id_
Sample *	sample_
SampleBuffer *	sample_buffer_
intptr_t	skip_count_
intptr_t	frames_skipped_
intptr_t	frame_index_
intptr_t	total_frames_

Detailed Description

Definition at line 217 of file profiler.cc.

Constructor & Destructor Documentation

ProfilerNativeStackWalker()

dart::ProfilerNativeStackWalker::ProfilerNativeStackWalker ( ProfilerCounters *  counters, Dart_Port  port_id, Sample *  sample, SampleBuffer *  sample_buffer, uword  stack_lower, uword  stack_upper, uword  pc, uword  fp, uword  sp, intptr_t  skip_count = 0  )

inline

Definition at line 219 of file profiler.cc.

      : ProfilerStackWalker(port_id, sample, sample_buffer, skip_count),
        counters_(counters),
        stack_upper_(stack_upper),
        original_pc_(pc),
        original_fp_(fp),
        original_sp_(sp),
        lower_bound_(stack_lower) {}

Member Function Documentation

walk()

void dart::ProfilerNativeStackWalker::walk ( )

inline

Definition at line 237 of file profiler.cc.

              {
    const uword kMaxStep = VirtualMemory::PageSize();
 
    Append(original_pc_, original_fp_);
 
    uword* pc = reinterpret_cast<uword*>(original_pc_);
    uword* fp = reinterpret_cast<uword*>(original_fp_);
    uword* previous_fp = fp;
 
    uword gap = original_fp_ - original_sp_;
    if (gap >= kMaxStep) {
      // Gap between frame pointer and stack pointer is
      // too large.
      counters_->incomplete_sample_fp_step.fetch_add(1);
      return;
    }
 
    if (!ValidFramePointer(fp)) {
      counters_->incomplete_sample_fp_bounds.fetch_add(1);
      return;
    }
 
    while (true) {
      pc = CallerPC(fp);
      previous_fp = fp;
      fp = CallerFP(fp);
 
      if (fp == nullptr) {
        return;
      }
 
      if (fp <= previous_fp) {
        // Frame pointer did not move to a higher address.
        counters_->incomplete_sample_fp_step.fetch_add(1);
        return;
      }
 
      gap = fp - previous_fp;
      if (gap >= kMaxStep) {
        // Frame pointer step is too large.
        counters_->incomplete_sample_fp_step.fetch_add(1);
        return;
      }
 
      if (!ValidFramePointer(fp)) {
        // Frame pointer is outside of isolate stack boundary.
        counters_->incomplete_sample_fp_bounds.fetch_add(1);
        return;
      }
 
      const uword pc_value = reinterpret_cast<uword>(pc);
      if ((pc_value + 1) < pc_value) {
        // It is not uncommon to encounter an invalid pc as we
        // traverse a stack frame.  Most of these we can tolerate.  If
        // the pc is so large that adding one to it will cause an
        // overflow it is invalid and it will cause headaches later
        // while we are building the profile.  Discard it.
        counters_->incomplete_sample_bad_pc.fetch_add(1);
        return;
      }
 
      // Move the lower bound up.
      lower_bound_ = reinterpret_cast<uword>(fp);
 
      if (!Append(pc_value, reinterpret_cast<uword>(fp))) {
        return;
      }
    }
  }

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The documentation for this class was generated from the following file:

• third_party/dart-lang/sdk/runtime/vm/profiler.cc