deps: backport e093a04, 09db540 from upstream V8

Original commit messages: v8/v8@e093a04 Rehash and clear deleted entries in weak collections during GC Otherwise, they'll just keep growing until we run out of memory or hit the FixedArray's maximum capacity. BUG=v8:4909 [email protected] LOG=n Review URL: https://codereview.chromium.org/1877233005 Cr-Commit-Position: refs/heads/master@{nodejs#35514} v8/v8@09db540 Reland of Rehash and clear deleted entries in weak collections during GC BUG=v8:4909 [email protected],[email protected] LOG=n Review URL: https://codereview.chromium.org/1890123002 Cr-Commit-Position: refs/heads/master@{nodejs#35538} V8-Bug: https://crbug.com/v8/4909 Fixes: nodejs#6180
ofrobots · Apr 15, 2016 · 244cc9e · 244cc9e
1 parent 61167c3
commit 244cc9e
Show file tree

Hide file tree

Showing 5 changed files with 40 additions and 3 deletions.
diff --git a/deps/v8/src/heap/mark-compact.cc b/deps/v8/src/heap/mark-compact.cc
@@ -2587,6 +2587,13 @@ void MarkCompactCollector::ClearWeakCollections() {
           table->RemoveEntry(i);
         }
       }
+      // Rehash if more than 25% of the entries are deleted entries.
+      // TODO(jochen): Consider to shrink the fixed array in place.
+      if ((table->NumberOfDeletedElements() << kJSWeakCollectionLoadFactorExp) >
+          table->NumberOfElements()) {
+        HandleScope scope(heap()->isolate());
+        table->Rehash(heap()->isolate()->factory()->undefined_value());
+      }
     }
     weak_collection_obj = weak_collection->next();
     weak_collection->set_next(heap()->undefined_value());

diff --git a/deps/v8/src/heap/mark-compact.h b/deps/v8/src/heap/mark-compact.h
@@ -541,6 +541,10 @@ class MarkCompactCollector {
   static const uint32_t kSingleFreeEncoding = 0;
   static const uint32_t kMultiFreeEncoding = 1;
 
+  // If the number of deleted slots in a JSWeakCollection exceeds the number
+  // of entries / 2^(factor), we rehash the table.
+  static const int kJSWeakCollectionLoadFactorExp = 1;
+
   static inline bool IsMarked(Object* obj);
   static bool IsUnmarkedHeapObjectWithHeap(Heap* heap, Object** p);
 

diff --git a/deps/v8/src/objects.cc b/deps/v8/src/objects.cc
@@ -13483,6 +13483,16 @@ void HashTable<Derived, Shape, Key>::Rehash(Key key) {
       }
     }
   }
+  // Wipe deleted entries.
+  Heap* heap = GetHeap();
+  Object* the_hole = heap->the_hole_value();
+  Object* undefined = heap->undefined_value();
+  for (uint32_t current = 0; current < capacity; current++) {
+    if (get(EntryToIndex(current)) == the_hole) {
+      set(EntryToIndex(current), undefined);
+    }
+  }
+  SetNumberOfDeletedElements(0);
 }
 
 
@@ -14292,6 +14302,16 @@ void CompilationCacheTable::Age() {
       }
     }
   }
+  // Wipe deleted entries.
+  Heap* heap = GetHeap();
+  Object* the_hole = heap->the_hole_value();
+  Object* undefined = heap->undefined_value();
+  for (uint32_t current = 0; current < capacity; current++) {
+    if (get(EntryToIndex(current)) == the_hole) {
+      set(EntryToIndex(current), undefined);
+    }
+  }
+  SetNumberOfDeletedElements(0);
 }
 
 
@@ -14779,6 +14799,12 @@ Handle<ObjectHashTable> ObjectHashTable::Put(Handle<ObjectHashTable> table,
     return table;
   }
 
+  // Rehash if more than 25% of the entries are deleted entries.
+  // TODO(jochen): Consider to shrink the fixed array in place.
+  if ((table->NumberOfDeletedElements() << 1) > table->NumberOfElements()) {
+    table->Rehash(isolate->factory()->undefined_value());
+  }
+
   // Check whether the hash table should be extended.
   table = EnsureCapacity(table, 1, key);
   table->AddEntry(table->FindInsertionEntry(hash), *key, *value);

diff --git a/deps/v8/test/cctest/test-weakmaps.cc b/deps/v8/test/cctest/test-weakmaps.cc
@@ -123,7 +123,7 @@ TEST(Weakness) {
   heap->CollectAllGarbage(false);
   CHECK_EQ(1, NumberOfWeakCalls);
   CHECK_EQ(0, ObjectHashTable::cast(weakmap->table())->NumberOfElements());
-  CHECK_EQ(2,
+  CHECK_EQ(0,
            ObjectHashTable::cast(weakmap->table())->NumberOfDeletedElements());
 }
 

diff --git a/deps/v8/test/cctest/test-weaksets.cc b/deps/v8/test/cctest/test-weaksets.cc
@@ -122,8 +122,8 @@ TEST(WeakSet_Weakness) {
   heap->CollectAllGarbage(false);
   CHECK_EQ(1, NumberOfWeakCalls);
   CHECK_EQ(0, ObjectHashTable::cast(weakset->table())->NumberOfElements());
-  CHECK_EQ(
-      1, ObjectHashTable::cast(weakset->table())->NumberOfDeletedElements());
+  CHECK_EQ(0,
+           ObjectHashTable::cast(weakset->table())->NumberOfDeletedElements());
 }