[heap] Parallel newspace evacuation, semispace copy, and compaction \o/

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index b49393d6655281272247d7470f8dbbe875cc64b9..eb4fe3fe8bdfeb7a490bd1354741835899aaa0ed 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -519,17 +519,19 @@ void Heap::MergeAllocationSitePretenuringFeedback(
     if (map_word.IsForwardingAddress()) {
       site = AllocationSite::cast(map_word.ToForwardingAddress());
     }
-    DCHECK(site->IsAllocationSite());
+
+    // We have not validated the allocation site yet, since we have not
+    // dereferenced the site during collecting information.
+    // This is an inlined check of AllocationMemento::IsValid.
+    if (!site->IsAllocationSite() || site->IsZombie()) continue;
+
     int value =
         static_cast<int>(reinterpret_cast<intptr_t>(local_entry->value));
     DCHECK_GT(value, 0);
 
-    {
-      // TODO(mlippautz): For parallel processing we need synchronization here.
-      if (site->IncrementMementoFoundCount(value)) {
-        global_pretenuring_feedback_->LookupOrInsert(
-            site, static_cast<uint32_t>(bit_cast<uintptr_t>(site)));
-      }
+    if (site->IncrementMementoFoundCount(value)) {
+      global_pretenuring_feedback_->LookupOrInsert(
+          site, static_cast<uint32_t>(bit_cast<uintptr_t>(site) >> 3));
     }
   }
 }