Build new IR for functions returning a constant

sdk/lib/_internal/compiler/implementation/elements/modelx.dart

Index: sdk/lib/_internal/compiler/implementation/elements/modelx.dart
diff --git a/sdk/lib/_internal/compiler/implementation/elements/modelx.dart b/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
index 8859321f1df3f619887a60f58a4f384312b63fa3..4daa412839154afdf6f16fe32942400d7231ae2d 100644
--- a/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
+++ b/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
@@ -29,6 +29,7 @@ import '../dart_types.dart';
 
 import '../scanner/scannerlib.dart' show Token, EOF_TOKEN;
 
+import '../ir/ir_nodes.dart' show IrNode, IrFunction;
 
 class ElementX implements Element {
   static int elementHashCode = 0;
@@ -53,6 +54,12 @@ class ElementX implements Element {
     compiler.internalError("$this.computeType.", token: position());
   }
 
+  bool hasIrNode(Compiler compiler) => false;
+
+  IrNode irNode(Compiler compiler) {
+    compiler.internalError("$this.irNode.", token: position());
+  }
+
   void addMetadata(MetadataAnnotation annotation) {
     assert(annotation.annotatedElement == null);
     annotation.annotatedElement = this;
@@ -1448,6 +1455,12 @@ class FunctionElementX extends ElementX implements FunctionElement {
 
   bool get isRedirectingFactory => defaultImplementation != this;
 
+  bool hasIrNode(Compiler compiler) {
+    return compiler.irBuilder.nodes.containsKey(this);
+  }
+
+  IrNode irNode(Compiler compiler) => compiler.irBuilder.nodes[this];
+
   /// This field is set by the post process queue when checking for cycles.
   FunctionElement internalRedirectionTarget;
   DartType redirectionTargetType;