Keep track of array buffers in new space separately

src/heap/mark-compact.cc

Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index 7e02afa3c9ebe65c982d8dffed41b3819e5574f5..ce996e958042201d726197fdaf31b574f6d30eaa 100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -3106,6 +3106,9 @@ bool MarkCompactCollector::TryPromoteObject(HeapObject* object,
 #endif
   if (allocation.To(&target)) {
     MigrateObject(target, object, object_size, old_space->identity());
+    if (target->IsJSArrayBuffer()) {
+      heap()->PromoteArrayBuffer(JSArrayBuffer::cast(target));

[Hannes Payer (out of office), 2015/05/12 06:33:28]

I think we should clean that up together with the specialized code in migrate
object. I like the idea of having a MigrationEpilog. Let's try that and see how
it looks.

+    }
     heap()->IncrementPromotedObjectsSize(object_size);
     return true;
   }
@@ -4412,7 +4415,6 @@ void MarkCompactCollector::SweepSpaces() {
 #ifdef DEBUG
   state_ = SWEEP_SPACES;
 #endif
-  heap()->FreeDeadArrayBuffers();
 
   MoveEvacuationCandidatesToEndOfPagesList();
 
@@ -4440,6 +4442,8 @@ void MarkCompactCollector::SweepSpaces() {
 
   EvacuateNewSpaceAndCandidates();
 
+  heap()->FreeDeadArrayBuffers(false);
+
   // ClearNonLiveReferences depends on precise sweeping of map space to
   // detect whether unmarked map became dead in this collection or in one
   // of the previous ones.