Bookkeeping for allocation site pretenuring

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index acd36a938e4489f6f5d91bf0ea88fe6c84e11077..5cc06723c0368f60c0bb40acd7685ed5213d7d24 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -406,8 +406,6 @@ 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());
 
@@ -449,11 +447,6 @@ 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;
 }
 
@@ -1889,6 +1882,14 @@ class MarkCompactWeakObjectRetainer : public WeakObjectRetainer {
   virtual Object* RetainAs(Object* object) {
     if (Marking::MarkBitFrom(HeapObject::cast(object)).Get()) {
       return object;
+    } else if (object->IsAllocationSite() &&
+               !(AllocationSite::cast(object)->IsZombie())) {
+      // "dead" AllocationSites need to live long enough for a traversal of new
+      // space. These sites get a one-time reprieve.
+      AllocationSite* site = AllocationSite::cast(object);
+      site->MarkZombie();
+      site->GetHeap()->mark_compact_collector()->MarkAllocationSite(site);
+      return object;
     } else {
       return NULL;
     }
@@ -2000,12 +2001,7 @@ 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_++;
-        }
-      }
+      Heap::UpdateAllocationSiteFeedback(object);
 
       offset++;
       current_cell >>= 1;
@@ -2098,6 +2094,12 @@ void MarkCompactCollector::MarkStringTable(RootMarkingVisitor* visitor) {
 }
 
 
+void MarkCompactCollector::MarkAllocationSite(AllocationSite* site) {
+  MarkBit mark_bit = Marking::MarkBitFrom(site);
+  SetMark(site, mark_bit);
+}
+
+
 void MarkCompactCollector::MarkRoots(RootMarkingVisitor* visitor) {
   // Mark the heap roots including global variables, stack variables,
   // etc., and all objects reachable from them.