Add InstanceType for EphemeronHashTable

This will allow the GC to differentiate between regular HashTables and EphemeronHashTables.

Bug: chromium:844008
Change-Id: I2f9009ac25eb117de03786b110dd362b829c5e9e
Reviewed-on: https://chromium-review.googlesource.com/1089066Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@google.com>
Cr-Commit-Position: refs/heads/master@{#53577}

src/compiler/types.cc

@@ -254,6 +254,7 @@ Type::bitset BitsetType::Lub(HeapReferenceType const& type) {
     case ACCESSOR_PAIR_TYPE:
     case FIXED_ARRAY_TYPE:
     case HASH_TABLE_TYPE:
+    case EPHEMERON_HASH_TABLE_TYPE:
     case WEAK_FIXED_ARRAY_TYPE:
     case WEAK_ARRAY_LIST_TYPE:
     case FIXED_DOUBLE_ARRAY_TYPE:

src/heap/heap.h

@@ -140,6 +140,7 @@ using v8::MemoryPressureLevel;
   V(Map, string_table_map, StringTableMap)                                     \
   V(Map, weak_fixed_array_map, WeakFixedArrayMap)                              \
   V(Map, weak_array_list_map, WeakArrayListMap)                                \
+  V(Map, ephemeron_hash_table_map, EphemeronHashTableMap)                      \
   /* String maps */                                                            \
   V(Map, native_source_string_map, NativeSourceStringMap)                      \
   V(Map, string_map, StringMap)                                                \
@@ -326,6 +327,7 @@ using v8::MemoryPressureLevel;
   V(CodeMap)                            \
   V(DebugEvaluateContextMap)            \
   V(DescriptorArrayMap)                 \
+  V(EphemeronHashTableMap)              \
   V(EmptyByteArray)                     \
   V(EmptyDescriptorArray)               \
   V(EmptyFixedArray)                    \

src/heap/mark-compact-inl.h

@@ -103,7 +103,7 @@ int MarkingVisitor<fixed_array_mode, retaining_path_mode, MarkingState>::
                                                     this);
 
   // Partially initialized weak collection is enqueued, but table is ignored.
-  if (!weak_collection->table()->IsHashTable()) return size;
+  if (!weak_collection->table()->IsEphemeronHashTable()) return size;
 
   // Mark the backing hash table without pushing it on the marking stack.
   Object** slot =

src/heap/mark-compact.cc

@@ -1878,6 +1878,8 @@ void MarkCompactCollector::ProcessWeakCollections() {
           visitor.VisitPointer(table, value_slot);
         }
       }
+    } else {
+      DCHECK(weak_collection->table()->IsUndefined(isolate()));
     }
     weak_collection_obj = weak_collection->next();
   }
@@ -1899,6 +1901,8 @@ void MarkCompactCollector::ClearWeakCollections() {
           table->RemoveEntry(i);
         }
       }
+    } else {
+      DCHECK(weak_collection->table()->IsUndefined(isolate()));
     }
     weak_collection_obj = weak_collection->next();
     weak_collection->set_next(heap()->undefined_value());

src/heap/setup-heap-internal.cc

@@ -458,6 +458,8 @@ bool Heap::CreateInitialMaps() {
     ALLOCATE_VARSIZE_MAP(HASH_TABLE_TYPE, simple_number_dictionary)
     ALLOCATE_VARSIZE_MAP(HASH_TABLE_TYPE, string_table)
 
+    ALLOCATE_VARSIZE_MAP(EPHEMERON_HASH_TABLE_TYPE, ephemeron_hash_table)
+
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, array_list)
 
     ALLOCATE_VARSIZE_MAP(FUNCTION_CONTEXT_TYPE, function_context)

src/objects-body-descriptors-inl.h

@@ -602,6 +602,7 @@ ReturnType BodyDescriptorApply(InstanceType type, T1 p1, T2 p2, T3 p3, T4 p4) {
     case FIXED_ARRAY_TYPE:
     case BOILERPLATE_DESCRIPTION_TYPE:
     case HASH_TABLE_TYPE:
+    case EPHEMERON_HASH_TABLE_TYPE:
     case SCOPE_INFO_TYPE:
     case BLOCK_CONTEXT_TYPE:
     case CATCH_CONTEXT_TYPE:

src/objects-debug.cc

@@ -132,6 +132,7 @@ void HeapObject::HeapObjectVerify() {
       CallHandlerInfo::cast(this)->CallHandlerInfoVerify();
       break;
     case HASH_TABLE_TYPE:
+    case EPHEMERON_HASH_TABLE_TYPE:
     case BOILERPLATE_DESCRIPTION_TYPE:
     case FIXED_ARRAY_TYPE:
     case SCOPE_INFO_TYPE:
@@ -1186,7 +1187,7 @@ void JSWeakMap::JSWeakMapVerify() {
   CHECK(IsJSWeakMap());
   JSObjectVerify();
   VerifyHeapPointer(table());
-  CHECK(table()->IsHashTable() || table()->IsUndefined(GetIsolate()));
+  CHECK(table()->IsEphemeronHashTable() || table()->IsUndefined(GetIsolate()));
 }
 
 void JSArrayIterator::JSArrayIteratorVerify() {
@@ -1227,7 +1228,7 @@ void JSWeakSet::JSWeakSetVerify() {
   CHECK(IsJSWeakSet());
   JSObjectVerify();
   VerifyHeapPointer(table());
-  CHECK(table()->IsHashTable() || table()->IsUndefined(GetIsolate()));
+  CHECK(table()->IsEphemeronHashTable() || table()->IsUndefined(GetIsolate()));
 }
 
 void Microtask::MicrotaskVerify() { CHECK(IsMicrotask()); }

src/objects-inl.h

@@ -83,6 +83,7 @@ TYPE_CHECKER(CodeDataContainer, CODE_DATA_CONTAINER_TYPE)
 TYPE_CHECKER(ConstantElementsPair, TUPLE2_TYPE)
 TYPE_CHECKER(CoverageInfo, FIXED_ARRAY_TYPE)
 TYPE_CHECKER(DescriptorArray, DESCRIPTOR_ARRAY_TYPE)
+TYPE_CHECKER(EphemeronHashTable, EPHEMERON_HASH_TABLE_TYPE)
 TYPE_CHECKER(FeedbackCell, FEEDBACK_CELL_TYPE)
 TYPE_CHECKER(FeedbackMetadata, FEEDBACK_METADATA_TYPE)
 TYPE_CHECKER(FeedbackVector, FEEDBACK_VECTOR_TYPE)
@@ -505,8 +506,6 @@ bool HeapObject::IsMapCache() const { return IsHashTable(); }
 
 bool HeapObject::IsObjectHashTable() const { return IsHashTable(); }
 
-bool HeapObject::IsEphemeronHashTable() const { return IsHashTable(); }
-
 bool HeapObject::IsOrderedHashSet() const {
   return map() == GetHeap()->ordered_hash_set_map();
 }

src/objects-printer.cc

@@ -98,6 +98,7 @@ void HeapObject::HeapObjectPrint(std::ostream& os) {  // NOLINT
       FixedDoubleArray::cast(this)->FixedDoubleArrayPrint(os);
       break;
     case HASH_TABLE_TYPE:
+    case EPHEMERON_HASH_TABLE_TYPE:
     case FIXED_ARRAY_TYPE:
     case BLOCK_CONTEXT_TYPE:
     case CATCH_CONTEXT_TYPE:
@@ -863,8 +864,15 @@ void PrintWeakArrayListWithHeader(std::ostream& os, WeakArrayList* array) {
 }  // namespace
 
 void FixedArray::FixedArrayPrint(std::ostream& os) {  // NOLINT
-  PrintFixedArrayWithHeader(os, this,
-                            IsHashTable() ? "HashTable" : "FixedArray");
+  const char* name = "FixedArray";
+
+  if (IsHashTable()) {
+    name = "HashTable";
+  } else if (IsEphemeronHashTable()) {
+    name = "EphemeronHashTable";
+  }
+
+  PrintFixedArrayWithHeader(os, this, name);
 }
 
 void BoilerplateDescription::BoilerplateDescriptionPrint(std::ostream& os) {

src/objects.cc

@@ -2979,6 +2979,7 @@ VisitorId Map::GetVisitorId(Map* map) {
     case FIXED_ARRAY_TYPE:
     case BOILERPLATE_DESCRIPTION_TYPE:
     case HASH_TABLE_TYPE:
+    case EPHEMERON_HASH_TABLE_TYPE:
     case SCOPE_INFO_TYPE:
     case BLOCK_CONTEXT_TYPE:
     case CATCH_CONTEXT_TYPE:

src/objects.h

@@ -416,6 +416,7 @@ const int kStubMinorKeyBits = kSmiValueSize - kStubMajorKeyBits - 1;
   V(FIXED_ARRAY_TYPE)                                           \
   V(BOILERPLATE_DESCRIPTION_TYPE)                               \
   V(HASH_TABLE_TYPE)                                            \
+  V(EPHEMERON_HASH_TABLE_TYPE)                                  \
   V(SCOPE_INFO_TYPE)                                            \
                                                                 \
   V(BLOCK_CONTEXT_TYPE)                                         \
@@ -799,6 +800,7 @@ enum InstanceType : uint16_t {
   FIXED_ARRAY_TYPE,  // FIRST_FIXED_ARRAY_TYPE
   BOILERPLATE_DESCRIPTION_TYPE,
   HASH_TABLE_TYPE,
+  EPHEMERON_HASH_TABLE_TYPE,
   SCOPE_INFO_TYPE,
   BLOCK_CONTEXT_TYPE,  // FIRST_CONTEXT_TYPE
   CATCH_CONTEXT_TYPE,

src/objects/hash-table-inl.h

@@ -58,6 +58,10 @@ int BaseShape<Key>::GetMapRootIndex() {
   return Heap::kHashTableMapRootIndex;
 }
 
+int EphemeronHashTableShape::GetMapRootIndex() {
+  return Heap::kEphemeronHashTableMapRootIndex;
+}
+
 template <typename Derived, typename Shape>
 int HashTable<Derived, Shape>::FindEntry(Key key) {
   return FindEntry(GetIsolate(), key);

src/objects/hash-table.h

@@ -312,7 +312,10 @@ class ObjectHashTable
   DECL_CAST(ObjectHashTable)
 };
 
-typedef ObjectHashTableShape EphemeronHashTableShape;
+class EphemeronHashTableShape : public ObjectHashTableShape {
+ public:
+  static inline int GetMapRootIndex();
+};
 
 // EphemeronHashTable is similar to ObjectHashTable but gets special treatment
 // by the GC. The GC treats its entries as ephemerons: both key and value are

src/profiler/heap-snapshot-generator.cc

@@ -1037,7 +1037,7 @@ void V8HeapExplorer::ExtractJSCollectionReferences(int entry,
 
 void V8HeapExplorer::ExtractJSWeakCollectionReferences(int entry,
                                                        JSWeakCollection* obj) {
-  if (obj->table()->IsHashTable()) {
+  if (obj->table()->IsEphemeronHashTable()) {
     EphemeronHashTable* table = EphemeronHashTable::cast(obj->table());
     TagFixedArraySubType(table, JS_WEAK_COLLECTION_SUB_TYPE);
   }