Implement aging of maps embedded in optimized code.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index ab13412f52989ecc7eb9e6510ab6d46afe0a9e73..4754c8afae2b5ff492ed1349f2054982c4dc6159 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -14211,7 +14211,10 @@ template class HashTable<ObjectHashTable,
                          ObjectHashTableShape,
                          Handle<Object> >;
 
-template class HashTable<WeakHashTable, WeakHashTableShape<2>, Handle<Object> >;
+template class HashTable<WeakHashTable, HeapPointerShape<2>, Handle<Object> >;
+
+template class HashTable<EmbeddedMapCache, HeapPointerShape<2>,
+                         Handle<Object> >;
 
 template class Dictionary<NameDictionary, NameDictionaryShape, Handle<Name> >;
 
@@ -15690,6 +15693,45 @@ void WeakHashTable::AddEntry(int entry,
 }
 
 
+Handle<EmbeddedMapCache> EmbeddedMapCache::Put(Handle<EmbeddedMapCache> table,
+                                               Handle<Map> key) {
+  DCHECK(table->IsKey(*key));
+  int entry = table->FindEntry(key);
+  // Key is already in table, just overwrite value.
+  if (entry != kNotFound) {
+    table->set(EntryToValueIndex(entry), Smi::FromInt(0), SKIP_WRITE_BARRIER);
+    return table;
+  }
+
+  // Check whether the hash table should be extended.
+  table = EnsureCapacity(table, 1, key, TENURED);
+  DisallowHeapAllocation no_allocation;
+  entry = table->FindInsertionEntry(table->Hash(key));
+  table->set(EntryToIndex(entry), *key);
+  table->set(EntryToValueIndex(entry), Smi::FromInt(0), SKIP_WRITE_BARRIER);
+  table->ElementAdded();
+  return table;
+}
+
+
+void EmbeddedMapCache::Age() {
+  int capacity = Capacity();
+  for (int i = 0; i < capacity; i++) {
+    Object* value = get(EntryToValueIndex(i));
+    if (value->IsSmi()) {
+      int age = Smi::cast(value)->value();
+      if (age > kMaxAge) {
+        set_the_hole(EntryToIndex(i));
+        set_the_hole(EntryToIndex(i) + 1);
+        ElementRemoved();
+      } else {
+        set(EntryToValueIndex(i), Smi::FromInt(age + 1), SKIP_WRITE_BARRIER);
+      }
+    }
+  }
+}
+
+
 template<class Derived, class Iterator, int entrysize>
 Handle<Derived> OrderedHashTable<Derived, Iterator, entrysize>::Allocate(
     Isolate* isolate, int capacity, PretenureFlag pretenure) {