Implement canonical name scheme in kernel.

runtime/vm/kernel.cc

Index: runtime/vm/kernel.cc
diff --git a/runtime/vm/kernel.cc b/runtime/vm/kernel.cc
index 48dcbdeeb7b13cbe35a67e1a0ae8b3ec0d6494ec..cd5af0f0c2bd42475214a440f9a6bec24464439a 100644
--- a/runtime/vm/kernel.cc
+++ b/runtime/vm/kernel.cc
@@ -18,6 +18,70 @@ void VisitList(List<T>* list, Visitor* visitor) {
 }
 
 
+CanonicalName::CanonicalName() : is_referenced_(false) {}
+
+
+CanonicalName* CanonicalName::NewRoot() {
+  return new CanonicalName();
+}
+
+
+void CanonicalName::LinkTo(LinkedNode* new_target) {
+  ASSERT(new_target != NULL);
+  if (definition_ == new_target) return;
+  ASSERT(definition_ == NULL);
+  ASSERT(new_target->canonical_name_ == NULL);
+  definition_ = new_target;
+  new_target->canonical_name_ = this;
+}
+
+
+void CanonicalName::Unlink() {
+  if (definition_ == NULL) return;
+  ASSERT(definition_->canonical_name_ == this);
+  definition_->canonical_name_ = NULL;
+  definition_ = NULL;
+}
+
+
+CanonicalName* CanonicalName::AddChild(String* name) {
+  CanonicalName* child = new CanonicalName();
+  child->parent_ = this;
+  child->name_ = name;
+  return child;
+}
+
+
+Library* CanonicalName::AsLibrary() {
+  return Library::Cast(definition());
+}
+
+
+Class* CanonicalName::AsClass() {
+  return Class::Cast(definition());
+}
+
+
+Member* CanonicalName::AsMember() {
+  return Member::Cast(definition());
+}
+
+
+Field* CanonicalName::AsField() {
+  return Field::Cast(definition());
+}
+
+
+Constructor* CanonicalName::AsConstructor() {
+  return Constructor::Cast(definition());
+}
+
+
+Procedure* CanonicalName::AsProcedure() {
+  return Procedure::Cast(definition());
+}
+
+
 Node::~Node() {}
 
 
@@ -29,6 +93,9 @@ void TreeNode::AcceptVisitor(Visitor* visitor) {
 }
 
 
+LinkedNode::~LinkedNode() {}
+
+
 Library::~Library() {}