[heap] Add timer scopes to process weak cells and clear non-live references.

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/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 2198 matching lines @@
   if (FLAG_track_gc_object_stats) {
     if (FLAG_trace_gc_object_stats) {
       heap()->object_stats_->TraceObjectStats();
     }
     heap()->object_stats_->CheckpointObjectStats();
   }
 }
 
 
 void MarkCompactCollector::ClearNonLiveReferences() {
+  GCTracer::Scope gc_scope(heap()->tracer(),
+                           GCTracer::Scope::MC_NONLIVEREFERENCES);
   // Iterate over the map space, setting map transitions that go from
   // a marked map to an unmarked map to null transitions.  This action
   // is carried out only on maps of JSObjects and related subtypes.
   HeapObjectIterator map_iterator(heap()->map_space());
   for (HeapObject* obj = map_iterator.Next(); obj != NULL;
        obj = map_iterator.Next()) {
     Map* map = Map::cast(obj);
 
     if (!map->CanTransition()) continue;
 
@@ skipping 273 matching lines @@
     JSWeakCollection* weak_collection =
         reinterpret_cast<JSWeakCollection*>(weak_collection_obj);
     weak_collection_obj = weak_collection->next();
     weak_collection->set_next(heap()->undefined_value());
   }
   heap()->set_encountered_weak_collections(Smi::FromInt(0));
 }
 
 
 void MarkCompactCollector::ProcessAndClearWeakCells() {
+  GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_WEAKCELL);
   Object* weak_cell_obj = heap()->encountered_weak_cells();
   while (weak_cell_obj != Smi::FromInt(0)) {
     WeakCell* weak_cell = reinterpret_cast<WeakCell*>(weak_cell_obj);
     // We do not insert cleared weak cells into the list, so the value
     // cannot be a Smi here.
     HeapObject* value = HeapObject::cast(weak_cell->value());
     if (!MarkCompactCollector::IsMarked(value)) {
       // Cells for new-space objects embedded in optimized code are wrapped in
       // WeakCell and put into Heap::weak_object_to_code_table.
       // Such cells do not have any strong references but we want to keep them
@@ skipping 2064 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(host);
     if (Marking::IsBlack(mark_bit)) {
       RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host);
       RecordRelocSlot(&rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8