Implement class hierarchy analysis in the VM.

runtime/vm/object.cc

 // Copyright (c) 2012, 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/bigint_operations.h"
@@ skipping 1839 matching lines @@
 }
 
 
 void Class::set_interfaces(const Array& value) const {
   // Verification and resolving of interfaces occurs in finalizer.
   ASSERT(!value.IsNull());
   StorePointer(&raw_ptr()->interfaces_, value.raw());
 }
 
 
+void Class::AddDirectSubclass(const Class& subclass) const {
+  ASSERT(!subclass.IsNull());
+  ASSERT(subclass.SuperClass() == raw());
+  // Do not keep track of the direct subclasses of class Object.
+  // TODO(regis): Replace assert below with ASSERT(id() != kDartObjectCid).
+  ASSERT(!IsObjectClass());
+  GrowableObjectArray& direct_subclasses =
+      GrowableObjectArray::Handle(raw_ptr()->direct_subclasses_);
+  if (direct_subclasses.IsNull()) {
+    direct_subclasses = GrowableObjectArray::New(4, Heap::kOld);
+    StorePointer(&raw_ptr()->direct_subclasses_, direct_subclasses.raw());
+  }
+#if defined(DEBUG)
+  // Verify that the same class is not added twice.
+  for (intptr_t i = 0; i < direct_subclasses.Length(); i++) {
+    ASSERT(direct_subclasses.At(i) != subclass.raw());
+  }
+#endif
+  direct_subclasses.Add(subclass);
+}
+
+
 RawArray* Class::constants() const {
   return raw_ptr()->constants_;
 }
 
 void Class::set_constants(const Array& value) const {
   ASSERT(!value.IsNull());
   StorePointer(&raw_ptr()->constants_, value.raw());
 }
 
 
@@ skipping 9257 matching lines @@
   }
   return result.raw();
 }
 
 
 const char* WeakProperty::ToCString() const {
   return "WeakProperty";
 }
 
 }  // namespace dart