Added check to debug object migration crashes.

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 815cae5b5e397a6b874e23996db9db804cfe2b37..e646ba7ce07d33b5cea9546c2021e59bfddc1886 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -2734,11 +2734,15 @@ void MarkCompactCollector::MigrateObject(Address dst,
 
       if (heap_->InNewSpace(value)) {
         heap_->store_buffer()->Mark(dst_slot);
-      } else if (value->IsHeapObject() && IsOnEvacuationCandidate(value)) {
-        SlotsBuffer::AddTo(&slots_buffer_allocator_,
-                           &migration_slots_buffer_,
-                           reinterpret_cast<Object**>(dst_slot),
-                           SlotsBuffer::IGNORE_OVERFLOW);
+      } else if (value->IsHeapObject()) {
+        CHECK(heap_->TargetSpace(HeapObject::FromAddress(src)) ==

[Michael Starzinger, 2013/07/23 21:10:47]

Please add a TODO here that this should be turned into an ASSERT soon. We only
want this for one or two Canary builds.

Also this ASSERT has nothing to do with this particular location. It has to hold
at method entry after the destination space has been checked (e.g. at line
2728). Please move it up, out of the loop.

[Hannes Payer (out of office), 2013/07/24 09:04:12]

Done.

+              heap_->old_pointer_space());
+        if (IsOnEvacuationCandidate(value)) {
+          SlotsBuffer::AddTo(&slots_buffer_allocator_,
+                             &migration_slots_buffer_,
+                             reinterpret_cast<Object**>(dst_slot),
+                             SlotsBuffer::IGNORE_OVERFLOW);
+        }
       }
 
       src_slot += kPointerSize;