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

src/heap/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/scopeinfo.h"
 #include "src/base/bits.h"
@@ skipping 501 matching lines @@
     const HashMap& local_pretenuring_feedback) {
   AllocationSite* site = nullptr;
   for (HashMap::Entry* local_entry = local_pretenuring_feedback.Start();
        local_entry != nullptr;
        local_entry = local_pretenuring_feedback.Next(local_entry)) {
     site = reinterpret_cast<AllocationSite*>(local_entry->key);
     MapWord map_word = site->map_word();
     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));
     }
   }
 }
 
 
 class Heap::PretenuringScope {
  public:
   explicit PretenuringScope(Heap* heap) : heap_(heap) {
     heap_->global_pretenuring_feedback_ =
         new HashMap(HashMap::PointersMatch, kInitialFeedbackCapacity);
@@ skipping 5699 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8