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
  R=hpayer@chromium.org
  LOG=n

  Review URL: https://codereview.chromium.org/1877233005

  Cr-Commit-Position: refs/heads/master@{#35514}

v8/v8@09db540
  Reland of Rehash and clear deleted entries in weak collections during GC
  BUG=v8:4909
  R=hpayer@chromium.org,ulan@chromium.org
  LOG=n

  Review URL: https://codereview.chromium.org/1890123002

  Cr-Commit-Position: refs/heads/master@{#35538}

Ref: https://crbug.com/v8/4909
Ref: #7883
Fixes: #6180
PR-URL: #7689
Reviewed-By: Matt Loring <mattloring@google.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

deps/v8/src/heap/mark-compact.cc

@@ -2614,6 +2614,13 @@ 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());

deps/v8/src/heap/mark-compact.h

@@ -612,6 +612,10 @@ 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);
 

deps/v8/src/objects.cc

@@ -13744,6 +13744,16 @@ 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);
 }
 
 
@@ -14656,6 +14666,7 @@ Handle<CompilationCacheTable> CompilationCacheTable::PutRegExp(
 void CompilationCacheTable::Age() {
   DisallowHeapAllocation no_allocation;
   Object* the_hole_value = GetHeap()->the_hole_value();
+  uint32_t capacity = Capacity();
   for (int entry = 0, size = Capacity(); entry < size; entry++) {
     int entry_index = EntryToIndex(entry);
     int value_index = entry_index + 1;
@@ -14679,6 +14690,16 @@ 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);
 }
 
 
@@ -15187,6 +15208,12 @@ 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);

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());
 }
 

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());
 }