Updates incremental marking pass to collect object statistics.

src/heap/mark-compact.cc

 // Copyright 2012 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/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 1279 matching lines @@
   }
 };
 
 
 void MarkCompactMarkingVisitor::Initialize() {
   StaticMarkingVisitor<MarkCompactMarkingVisitor>::Initialize();
 
   table_.Register(kVisitJSRegExp, &VisitRegExpAndFlushCode);
 
   if (FLAG_track_gc_object_stats) {
-    ObjectStatsVisitor::Initialize(&table_);
+    MarkCompactObjectStatsVisitor::Initialize(&table_);
   }
 }
 
 
 class CodeMarkingVisitor : public ThreadVisitor {
  public:
   explicit CodeMarkingVisitor(MarkCompactCollector* collector)
       : collector_(collector) {}
 
   void VisitThread(Isolate* isolate, ThreadLocalTop* top) {
@@ skipping 890 matching lines @@
   PostponeInterruptsScope postpone(isolate());
 
   {
     TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_MARK_FINISH_INCREMENTAL);
     IncrementalMarking* incremental_marking = heap_->incremental_marking();
     if (was_marked_incrementally_) {
       incremental_marking->Finalize();
     } else {
       // Abort any pending incremental activities e.g. incremental sweeping.
       incremental_marking->Stop();
+      if (FLAG_track_gc_object_stats) {

[Hannes Payer (out of office), 2016/05/11 15:43:56]

I think it is cleaner to clear the object stats right after printing the trace
information.

[mythria, 2016/05/11 15:52:26]

They are already cleared after printing trace information (at the end of this
function). I thought we may have to clear here as well to avoid counting the
objects twice. I thought since we are aborting incremental marking the object
stats collected during incremental marking should be cleared. If it is just
sufficient to clear after printing trace information, I will just remove it.

+        // Clear object stats collected during incremental marking.
+        heap()->object_stats_->ClearObjectStats();
+      }
       if (marking_deque_.in_use()) {
         marking_deque_.Uninitialize(true);
       }
     }
   }
 
 #ifdef DEBUG
   DCHECK(state_ == PREPARE_GC);
   state_ = MARK_LIVE_OBJECTS;
 #endif
@@ skipping 1726 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(host);
     if (Marking::IsBlack(mark_bit)) {
       RelocInfo rinfo(isolate(), pc, RelocInfo::CODE_TARGET, 0, host);
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8