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..e554b3535455c2239d443523d169c578c702fa37 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), 2015/05/08 13:39:29]

Please don't add any JS type specific functionality to this function.

You could iterate over the map after evacuation and see what got promoted.

+    }
     heap()->IncrementPromotedObjectsSize(object_size);
     return true;
   }
@@ -4412,7 +4415,9 @@ void MarkCompactCollector::SweepSpaces() {
 #ifdef DEBUG
   state_ = SWEEP_SPACES;
 #endif
-  heap()->FreeDeadArrayBuffers();
+  // MarkCompact will always also evacuate the new space.
+  heap()->FreeDeadArrayBuffers(true);
+  heap()->FreeDeadArrayBuffers(false);
 
   MoveEvacuationCandidatesToEndOfPagesList();