[profiler] Implement POC Sampling Heap Profiler

src/profiler/heap-profiler.cc

 // Copyright 2009-2010 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/profiler/heap-profiler.h"
 
 #include "src/api.h"
+#include "src/base/utils/random-number-generator.h"
 #include "src/debug/debug.h"
+#include "src/frames-inl.h"
 #include "src/profiler/allocation-tracker.h"
 #include "src/profiler/heap-snapshot-generator-inl.h"
+#include "src/profiler/sampling-heap-profiler.h"
 
 namespace v8 {
 namespace internal {
 
 HeapProfiler::HeapProfiler(Heap* heap)
     : ids_(new HeapObjectsMap(heap)),
       names_(new StringsStorage(heap)),
       is_tracking_object_moves_(false) {
 }
 
@@ skipping 56 matching lines @@
   ids_->RemoveDeadEntries();
   is_tracking_object_moves_ = true;
 
   heap()->isolate()->debug()->feature_tracker()->Track(
       DebugFeatureTracker::kHeapSnapshot);
 
   return result;
 }
 
 
+bool HeapProfiler::StartSamplingHeapProfiler(uint64_t sample_interval,
+                                             int stack_depth) {
+  if (sampling_heap_profiler_.get()) {
+    return false;
+  }
+  sampling_heap_profiler_.Reset(new SamplingHeapProfiler(
+      heap(), names_.get(), sample_interval, stack_depth));
+  return true;
+}
+
+
+void HeapProfiler::StopSamplingHeapProfiler() {
+  sampling_heap_profiler_.Reset(nullptr);
+}
+
+
+void HeapProfiler::GetHeapSample(OutputStream* stream) {
+  if (sampling_heap_profiler_.get()) {
+    sampling_heap_profiler_->GetHeapSample(stream);
+  } else {
+    stream->EndOfStream();
+  }
+}
+
+
 void HeapProfiler::StartHeapObjectsTracking(bool track_allocations) {
   ids_->UpdateHeapObjectsMap();
   is_tracking_object_moves_ = true;
   DCHECK(!is_tracking_allocations());
   if (track_allocations) {
     allocation_tracker_.Reset(new AllocationTracker(ids_.get(), names_.get()));
     heap()->DisableInlineAllocation();
     heap()->isolate()->debug()->feature_tracker()->Track(
         DebugFeatureTracker::kAllocationTracking);
   }
@@ skipping 94 matching lines @@
   ids_.Reset(new HeapObjectsMap(heap()));
   if (!is_tracking_allocations()) is_tracking_object_moves_ = false;
 }
 
 
 Heap* HeapProfiler::heap() const { return ids_->heap(); }
 
 
 }  // namespace internal
 }  // namespace v8