Add NativeEnqueuer to work with the Enqueuer.

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

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart2js;
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
@@ skipping 56 matching lines @@
       : this.constantSystem = constantSystem;
 
   void enqueueAllTopLevelFunctions(LibraryElement lib, Enqueuer world) {
     lib.forEachExport((Element e) {
       if (e.isFunction()) world.addToWorkList(e);
     });
   }
 
   void enqueueHelpers(Enqueuer world);
   void codegen(WorkItem work);
-  void processNativeClasses(Enqueuer world,
-                            Collection<LibraryElement> libraries);
+
+  // The backend determines the native resolution enqueuer so tools like
+  // dart2dart can ignore the native classes.
+  NativeEnqueuer nativeResolutionEnqueuer(world);
+  NativeEnqueuer nativeCodegenEnqueuer(world);
+
   void assembleProgram();
   List<CompilerTask> get tasks;
 
   // TODO(ahe,karlklose): rename this?
   void dumpInferredTypes() {}
 
   ItemCompilationContext createItemCompilationContext() {
     return new ItemCompilationContext();
   }
 
@@ skipping 425 matching lines @@
       reportFatalError('Could not find $MAIN', mainApp);
     } else {
       if (!main.isFunction()) reportFatalError('main is not a function', main);
       FunctionElement mainMethod = main;
       FunctionSignature parameters = mainMethod.computeSignature(this);
       parameters.forEachParameter((Element parameter) {
         reportFatalError('main cannot have parameters', parameter);
       });
     }
 
+    enqueuer.resolution.nativeEnqueuer =
+        backend.nativeResolutionEnqueuer(enqueuer.resolution);
+    enqueuer.codegen.nativeEnqueuer =
+        backend.nativeCodegenEnqueuer(enqueuer.codegen);
+
     log('Resolving...');
     phase = PHASE_RESOLVING;
     backend.enqueueHelpers(enqueuer.resolution);
     processQueue(enqueuer.resolution, main);
     log('Resolved ${enqueuer.resolution.resolvedElements.length} elements.');
+    log('Resolved ${enqueuer.resolution.nativeEnqueuer.registeredClasses.length} native elements used, '
+        '${enqueuer.resolution.nativeEnqueuer.unusedClasses.length} native elements dead.');
 
     if (compilationFailed) return;
 
     log('Inferring types...');
     typesTask.onResolutionComplete(main);
 
     // TODO(ahe): Remove this line. Eventually, enqueuer.resolution
     // should know this.
     world.populate();
 
     log('Compiling...');
     phase = PHASE_COMPILING;
     processQueue(enqueuer.codegen, main);
     log('Compiled ${codegenWorld.generatedCode.length} methods.');
+    log('Compiled ${enqueuer.codegen.nativeEnqueuer.registeredClasses.length} native classes, '
+        '${enqueuer.codegen.nativeEnqueuer.unusedClasses.length} native classes omitted.');
 
     if (compilationFailed) return;
 
     backend.assembleProgram();
 
     checkQueues();
   }
 
   void processQueue(Enqueuer world, Element main) {
-    backend.processNativeClasses(world, libraries.values);
+    world.nativeEnqueuer.processNativeClasses(libraries.values);
     world.addToWorkList(main);
     progress.reset();
     world.forEach((WorkItem work) {
       withCurrentElement(work.element, () => work.run(this, world));
     });
     world.queueIsClosed = true;
     if (compilationFailed) return;
     assert(world.checkNoEnqueuedInvokedInstanceMethods());
     if (DUMP_INFERRED_TYPES && phase == PHASE_COMPILING) {
       backend.dumpInferredTypes();
@@ skipping 82 matching lines @@
       if (phase == PHASE_RESOLVING) {
         log('Resolved ${enqueuer.resolution.resolvedElements.length} '
             'elements.');
         progress.reset();
       }
     }
     Element element = work.element;
     TreeElements result = world.getCachedElements(element);
     if (result != null) return result;
     if (!identical(world, enqueuer.resolution)) {
+      throw 'Internal error: unresolved element: $element.';
       internalErrorOnElement(element,
                              'Internal error: unresolved element: $element.');
     }
     result = analyzeElement(element);
     assert(invariant(element, element.isDeclaration));
     enqueuer.resolution.resolvedElements[element] = result;
     return result;
   }
 
   void codegen(WorkItem work, Enqueuer world) {
@@ skipping 244 matching lines @@
   // TODO(johnniwinther): Use [spannable] and [message] to provide better
   // information on assertion errors.
   if (condition is Function){
     condition = condition();
   }
   if (spannable == null || !condition) {
     throw new SpannableAssertionFailure(spannable, message);
   }
   return true;
 }