Version 3.7.9.

src/spaces.cc

Index: src/spaces.cc
===================================================================
--- src/spaces.cc	(revision 10035)
+++ src/spaces.cc	(working copy)
@@ -1658,14 +1658,14 @@
   // field and a next pointer, we give it a filler map that gives it the
   // correct size.
   if (size_in_bytes > FreeSpace::kHeaderSize) {
-    set_map(heap->raw_unchecked_free_space_map());
+    set_map_unsafe(heap->raw_unchecked_free_space_map());
     // Can't use FreeSpace::cast because it fails during deserialization.
     FreeSpace* this_as_free_space = reinterpret_cast<FreeSpace*>(this);
     this_as_free_space->set_size(size_in_bytes);
   } else if (size_in_bytes == kPointerSize) {
-    set_map(heap->raw_unchecked_one_pointer_filler_map());
+    set_map_unsafe(heap->raw_unchecked_one_pointer_filler_map());
   } else if (size_in_bytes == 2 * kPointerSize) {
-    set_map(heap->raw_unchecked_two_pointer_filler_map());
+    set_map_unsafe(heap->raw_unchecked_two_pointer_filler_map());
   } else {
     UNREACHABLE();
   }