Build new IR for functions returning a constant

sdk/lib/_internal/compiler/implementation/ir/inodes.dart

+part of ir;
+
+class Position {
+  SourceFile sourceFile;

[ngeoffray, 2013/11/05 12:58:35]

Probably not something we want to put on each instruction.

[lukas, 2013/11/05 17:10:50]

True!

+  int offset;
+  Position(this.sourceFile, this.offset);
+}
+
+abstract class INode {
+  Position pos;
+  INode(this.pos);
+}
+
+class NoValue extends INode {
+  static NoValue _instance;

[ngeoffray, 2013/11/05 12:58:35]

How about a const constructor?

[lukas, 2013/11/05 17:10:50]

Yes, much better.

+  factory NoValue() {
+    if (_instance == null) _instance = new NoValue.internal();
+    return _instance;
+  }
+  NoValue.internal() : super(new Position(null, 0));
+}
+
+class IFunction extends INode {
+  List<INode> statements;
+  IFunction(Position pos, this.statements) : super(pos);
+
+  bool hasBody() => statements.isNotEmpty;
+}
+
+class IReturn extends INode {
+  IFunction function;
+  INode value;
+  IReturn(Position pos, this.function, this.value) : super(pos);
+}
+
+class IConstant extends INode {
+  Constant value;

[ngeoffray, 2013/11/05 12:58:35]

final?

[lukas, 2013/11/05 17:10:50]

Done.

+  IConstant(Position pos, this.value) : super(pos);
+}