Lazy implementation of final variables.

lib/compiler/implementation/compiler.dart

Index: lib/compiler/implementation/compiler.dart
diff --git a/lib/compiler/implementation/compiler.dart b/lib/compiler/implementation/compiler.dart
index 69234fe7f8c32557ec96fb69ee1ee7501d6430ed..21d14664e60e6fffe47cbeb2818e17f975f95892 100644
--- a/lib/compiler/implementation/compiler.dart
+++ b/lib/compiler/implementation/compiler.dart
@@ -749,13 +749,13 @@ class Compiler implements DiagnosticListener {
       progress.reset();
     }
     if (work.element.kind.category == ElementCategory.VARIABLE) {
-      constantHandler.compileWorkItem(work);
-      return null;
-    } else {
-      CodeBuffer codeBuffer = backend.codegen(work);
-      codegenWorld.addGeneratedCode(work, codeBuffer);
-      return codeBuffer.toString();
+      Constant initialValue = constantHandler.compileWorkItem(work);
+      if (initialValue != null) return null;
+      // Otherwise we need to go through the builder.

[kasperl, 2012/08/16 14:41:37]

Maybe change the comment to explain why we have to go through the builder for
this.

[floitsch, 2012/08/16 22:52:33]

Done.

     }
+    CodeBuffer codeBuffer = backend.codegen(work);
+    codegenWorld.addGeneratedCode(work, codeBuffer);
+    return codeBuffer.toString();
   }
 
   void registerInstantiatedClass(ClassElement cls) {
@@ -793,6 +793,18 @@ class Compiler implements DiagnosticListener {
         () => resolver.computeFunctionType(element, signature));
   }
 
+  bool isLazilyInitialized(VariableElement element) {
+    Constant initialValue = compileVariable(element);
+    return initialValue == null;

[kasperl, 2012/08/16 14:41:37]

===?

[floitsch, 2012/08/16 22:52:33]

Done.

+  }
+
+  /** Compiles compile-time constants. Must not return `null`. */
+  Constant compileConstant(VariableElement element) {
+    return withCurrentElement(element, () {
+      return constantHandler.compileConstant(element);
+    });
+  }
+
   Constant compileVariable(VariableElement element) {
     return withCurrentElement(element, () {
       return constantHandler.compileVariable(element);