Ensure that promotion queue does not overlap with objects relocated to ToSpace.

src/heap-inl.h

Index: src/heap-inl.h
diff --git a/src/heap-inl.h b/src/heap-inl.h
index c065b73daa70354c5652b7775d1f46b671b2d6d4..33bc2c7cb5649d60a1c9bfe6e89146a9a0e8c945 100644
--- a/src/heap-inl.h
+++ b/src/heap-inl.h
@@ -40,12 +40,26 @@ namespace v8 {
 namespace internal {
 
 void PromotionQueue::insert(HeapObject* target, int size) {
+  if (emergency_stack_ != NULL) {
+    emergency_stack_->Add(Entry(target, size));
+    return;
+  }
+
   if (NewSpacePage::IsAtStart(reinterpret_cast<Address>(rear_))) {
     NewSpacePage* rear_page =
         NewSpacePage::FromAddress(reinterpret_cast<Address>(rear_));
     ASSERT(!rear_page->prev_page()->is_anchor());
     rear_ = reinterpret_cast<intptr_t*>(rear_page->prev_page()->body_limit());
   }
+
+  Page* rear_page = Page::FromAddress(reinterpret_cast<Address>(rear_ - 2));
+  Page* limit_page = Page::FromAllocationTop(reinterpret_cast<Address>(limit_));
+  if (rear_page == limit_page && (rear_ - 2) < limit_) {
+    RelocateQueueHead();

[Erik Corry, 2011/11/07 16:35:25]

This one asserts that there is something to relocate.

+    emergency_stack_->Add(Entry(target, size));
+    return;
+  }
+
   *(--rear_) = reinterpret_cast<intptr_t>(target);
   *(--rear_) = size;
   // Assert no overflow into live objects.