Print out how many AllocationMementos were found during mark-sweep.

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 31ad1bacfb0f6eb72b8688de5b488bef3f9bea03..d9cb8dcda9d863631307a4f3a78d5fc2719d4927 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -407,6 +407,8 @@ void MarkCompactCollector::CollectGarbage() {
   ASSERT(state_ == PREPARE_GC);
   ASSERT(encountered_weak_collections_ == Smi::FromInt(0));
 
+  heap()->allocation_mementos_found_ = 0;
+
   MarkLiveObjects();
   ASSERT(heap_->incremental_marking()->IsStopped());
 
@@ -449,6 +451,11 @@ void MarkCompactCollector::CollectGarbage() {
     marking_parity_ = EVEN_MARKING_PARITY;
   }
 
+  if (FLAG_trace_track_allocation_sites &&
+      heap()->allocation_mementos_found_ > 0) {
+    PrintF("AllocationMementos found during mark-sweep = %d\n",
+           heap()->allocation_mementos_found_);
+  }
   tracer_ = NULL;
 }
 
@@ -2002,6 +2009,13 @@ int MarkCompactCollector::DiscoverAndPromoteBlackObjectsOnPage(
       int size = object->Size();
       survivors_size += size;
 
+      if (FLAG_trace_track_allocation_sites && object->IsJSObject()) {
+        if (AllocationMemento::FindForJSObject(JSObject::cast(object), true)
+            != NULL) {
+          heap()->allocation_mementos_found_++;
+        }
+      }
+
       offset++;
       current_cell >>= 1;
       // Aggressively promote young survivors to the old space.