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..7646fcaf121389cc57ffb13a3bd35febe94eedee 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -1889,6 +1889,14 @@ 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 +2008,7 @@ 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::AddressMemento(object);
 
       offset++;
       current_cell >>= 1;
@@ -2098,6 +2101,12 @@ 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.