Towards compiling Hello World!

pkg/compiler/lib/src/universe/codegen_world_builder.dart

Index: pkg/compiler/lib/src/universe/codegen_world_builder.dart
diff --git a/pkg/compiler/lib/src/universe/codegen_world_builder.dart b/pkg/compiler/lib/src/universe/codegen_world_builder.dart
index 409624961d863a400324b2f93936a657a3a90bd9..7df0e20de6ec1083905453b37d35fb6e1673f625 100644
--- a/pkg/compiler/lib/src/universe/codegen_world_builder.dart
+++ b/pkg/compiler/lib/src/universe/codegen_world_builder.dart
@@ -14,9 +14,9 @@ abstract class CodegenWorldBuilder implements WorldBuilder {
       ClassEntity cls, void f(ClassEntity declarer, FieldEntity field));
 
   /// Calls [f] for each parameter of [function] providing the type and name of
-  /// the parameter.
-  void forEachParameter(
-      FunctionEntity function, void f(DartType type, String name));
+  /// the parameter and the [defaultValue] if the parameter is optional.
+  void forEachParameter(FunctionEntity function,
+      void f(DartType type, String name, ConstantValue defaultValue));
 
   void forEachInvokedName(
       f(String name, Map<Selector, SelectorConstraints> selectors));
@@ -27,6 +27,9 @@ abstract class CodegenWorldBuilder implements WorldBuilder {
   void forEachInvokedSetter(
       f(String name, Map<Selector, SelectorConstraints> selectors));
 
+  /// Returns `true` if [field] constant or final with a constant initializer.
+  bool hasConstantFieldInitializer(FieldEntity field);
+
   /// Returns `true` if [member] is invoked as a setter.
   bool hasInvokedSetter(MemberEntity member, ClosedWorld world);
 
@@ -542,7 +545,10 @@ abstract class CodegenWorldBuilderImpl implements CodegenWorldBuilder {
 }
 
 class ElementCodegenWorldBuilderImpl extends CodegenWorldBuilderImpl {
+  final JavaScriptConstantCompiler _constants;
+
   ElementCodegenWorldBuilderImpl(
+      this._constants,
       ElementEnvironment elementEnvironment,
       NativeBasicData nativeBasicData,
       ClosedWorld world,
@@ -550,6 +556,11 @@ class ElementCodegenWorldBuilderImpl extends CodegenWorldBuilderImpl {
       : super(elementEnvironment, nativeBasicData, world,
             selectorConstraintsStrategy);
 
+  @override
+  bool hasConstantFieldInitializer(FieldElement field) {
+    return field.constant != null;
+  }
+
   /// Calls [f] with every instance field, together with its declarer, in an
   /// instance of [cls].
   void forEachInstanceField(
@@ -559,12 +570,18 @@ class ElementCodegenWorldBuilderImpl extends CodegenWorldBuilderImpl {
   }
 
   @override
-  void forEachParameter(
-      MethodElement function, void f(DartType type, String name)) {
+  void forEachParameter(MethodElement function,
+      void f(DartType type, String name, ConstantValue defaultValue)) {
     FunctionSignature parameters = function.functionSignature;
-    parameters.forEachParameter((_parameter) {
+    parameters.orderedForEachParameter((_parameter) {
       ParameterElement parameter = _parameter;
-      f(parameter.type, parameter.name);
+      ConstantValue value;
+      if (parameter.constant != null) {
+        value = _constants.getConstantValue(parameter.constant);
+      } else {
+        value = new NullConstantValue();
+      }
+      f(parameter.type, parameter.name, value);
     });
   }
 
@@ -600,7 +617,10 @@ class ElementCodegenWorldBuilderImpl extends CodegenWorldBuilderImpl {
 }
 
 class KernelCodegenWorldBuilder extends CodegenWorldBuilderImpl {
+  KernelToElementMapImpl _elementMap;
+
   KernelCodegenWorldBuilder(
+      this._elementMap,
       ElementEnvironment elementEnvironment,
       NativeBasicData nativeBasicData,
       ClosedWorld world,
@@ -609,9 +629,14 @@ class KernelCodegenWorldBuilder extends CodegenWorldBuilderImpl {
             selectorConstraintsStrategy);
 
   @override
-  void forEachParameter(
-      FunctionEntity function, void f(DartType type, String name)) {
-    throw new UnimplementedError('KernelCodegenWorldBuilder.forEachParameter');
+  bool hasConstantFieldInitializer(FieldEntity field) {
+    return _elementMap.hasConstantFieldInitializer(field);
+  }
+
+  @override
+  void forEachParameter(FunctionEntity function,
+      void f(DartType type, String name, ConstantValue defaultValue)) {
+    _elementMap.forEachParameter(function, f);
   }
 
   @override