Make function lookup in classes thread-safe:

runtime/vm/hash_table.h

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_HASH_TABLE_H_
 #define VM_HASH_TABLE_H_
 
 // Temporarily used when sorting the indices in EnumIndexHashTable.
 // TODO(koda): Remove these dependencies before using in production.
 #include <map>
@@ skipping 81 matching lines @@
         key_handle_(Object::Handle(zone_)),
         smi_handle_(Smi::Handle(zone_)),
         data_(&Array::Handle(zone_, data)),
         released_data_(NULL) {}
   // Like above, except uses current zone.
   explicit HashTable(RawArray* data)
       : zone_(Thread::Current()->zone()),
         key_handle_(Object::Handle(zone_)),
         smi_handle_(Smi::Handle(zone_)),
         data_(&Array::Handle(zone_, data)),
-        released_data_(NULL) {}
+        released_data_(NULL) {
+    ASSERT(!data_->IsNull());
+  }
 
   // Returns the final table. The handle is cleared when this HashTable is
   // destroyed.
   Array& Release() {
     ASSERT(data_ != NULL);
     ASSERT(released_data_ == NULL);
     // Ensure that no methods are called after 'Release'.
     released_data_ = data_;
     data_ = NULL;
     return *released_data_;
@@ skipping 176 matching lines @@
 
   RawObject* InternalGetKey(intptr_t entry) const {
     return data_->At(KeyIndex(entry));
   }
 
   void InternalSetKey(intptr_t entry, const Object& key) const {
     data_->SetAt(KeyIndex(entry), key);
   }
 
   intptr_t GetSmiValueAt(intptr_t index) const {
+    ASSERT(!data_->IsNull());
     ASSERT(Object::Handle(zone(), data_->At(index)).IsSmi());
     return Smi::Value(Smi::RawCast(data_->At(index)));
   }
 
   void SetSmiValueAt(intptr_t index, intptr_t value) const {
     smi_handle_ = Smi::New(value);
     data_->SetAt(index, smi_handle_);
   }
 
   void AdjustSmiValueAt(intptr_t index, intptr_t delta) const {
@@ skipping 373 matching lines @@
     // We currently never shrink.
     HashTables::EnsureLoadFactor(0.0, kMaxLoadFactor, *this);
   }
 };
 
 
 template<typename KeyTraits>
 class UnorderedHashSet : public HashSet<UnorderedHashTable<KeyTraits, 0> > {
  public:
   typedef HashSet<UnorderedHashTable<KeyTraits, 0> > BaseSet;
-  explicit UnorderedHashSet(RawArray* data) : BaseSet(data) {}
+  explicit UnorderedHashSet(RawArray* data) : BaseSet(data) {
+    ASSERT(data != Array::null());
+  }
   UnorderedHashSet(Zone* zone, RawArray* data) : BaseSet(zone, data) {}
 };
 
 
 template<typename KeyTraits>
 class EnumIndexHashSet : public HashSet<EnumIndexHashTable<KeyTraits, 0> > {
  public:
   typedef HashSet<EnumIndexHashTable<KeyTraits, 0> > BaseSet;
   explicit EnumIndexHashSet(RawArray* data) : BaseSet(data) {}
   EnumIndexHashSet(Zone* zone, RawArray* data) : BaseSet(zone, data) {}
 };
 
 }  // namespace dart
 
 #endif  // VM_HASH_TABLE_H_