RFC: Resolution based tree-shaking.

dart/lib/compiler/implementation/resolver.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.
 
 interface TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
   Type getType(TypeAnnotation annotation);
 }
 
@@ skipping 105 matching lines @@
     return compiler.withCurrentElement(element, () {
       bool isConstructor = element.kind === ElementKind.GENERATIVE_CONSTRUCTOR;
       if (constructorElements.containsKey(element)) {
         assert(isConstructor);
         TreeElements elements = constructorElements[element];
         if (elements !== null) return elements;
       }
       FunctionExpression tree = element.parseNode(compiler);
       if (isConstructor) {
         resolveConstructorImplementation(element, tree);
+        compiler.enqueuer.resolution.registerStaticUse(
+            element.defaultImplementation);
       }
       ResolverVisitor visitor = new ResolverVisitor(compiler, element);
       visitor.useElement(tree, element);
       visitor.setupFunction(tree, element);
 
       if (isConstructor) {
         // Even if there is no initializer list we still have to do the
         // resolution in case there is an implicit super constructor call.
         InitializerResolver resolver = new InitializerResolver(visitor);
         FunctionElement redirection =
@@ skipping 660 matching lines @@
       Element existing = context.add(element);
       if (existing != element) {
         error(node, MessageKind.DUPLICATE_DEFINITION, [node]);
       }
     }
     return element;
   }
 
   Element useElement(Node node, Element element) {
     if (element === null) return null;
+    ElementKind kind = element.kind;
+    if (element.isTopLevel() || element.isMember()) {
+      int allowed = ElementCategory.VARIABLE | ElementCategory.FUNCTION
+        | ElementCategory.FACTORY;
+      if ((element.kind.category & allowed) != 0 || element.isAccessor()) {
+        if (element.isInstanceMember()) {
+          compiler.enqueuer.resolution.registerDynamicInvocationOf(element);
+        } else {
+          compiler.enqueuer.resolution.registerStaticUse(element);
+        }
+      }
+    }
     return mapping[node] = element;
   }
 
   Type useType(TypeAnnotation annotation, Type type) {
     if (type !== null) {
       mapping.setType(annotation, type);
       useElement(annotation, type.element);
     }
     return type;
   }
@@ skipping 241 matching lines @@
     if (target === compiler.assertMethod && !node.isCall) {
       // We can only use assert by calling it.
       if (!inInstanceContext) {
         error(node, MessageKind.MISSING_ARGUMENTS_TO_ASSERT, [node]);
       }
       target = null;
     }
     // TODO(ngeoffray): Warn if target is null and the send is
     // unqualified.
     useElement(node, target);
+    if (target === null || target.isMember()) {
+      Identifier id = node.selector.asIdentifier();
+      if (id !== null) {
+        compiler.enqueuer.resolution.registerDynamicInvocation(
+            id.source,
+            mapping.getSelector(node));
+      }
+      // target = new Interceptors(compiler).getStaticInterceptor(
+      //     node.selector.asIdentifier().source,
+      //     node.argumentCount());
+    }
+    if (target !== null &&
+        target.kind !== ElementKind.VARIABLE &&
+        target.kind !== ElementKind.CLASS) {
+      if (target.isInstanceMember()) {
+        compiler.enqueuer.resolution.registerDynamicInvocationOf(target);
+      } else {
+        compiler.enqueuer.resolution.registerStaticUse(target);
+      }
+    }
     if (node.isPropertyAccess) return target;
   }
 
   visitSendSet(SendSet node) {
     Element target = resolveSend(node);
     Element setter = null;
     Element getter = null;
     if (target != null && target.kind == ElementKind.ABSTRACT_FIELD) {
       AbstractFieldElement field = target;
       setter = field.setter;
@@ skipping 84 matching lines @@
 
     FunctionElement constructor = resolveConstructor(node);
     handleArguments(node.send);
     if (constructor === null) return null;
     // TODO(karlklose): handle optional arguments.
     if (node.send.argumentCount() != constructor.parameterCount(compiler)) {
       // TODO(ngeoffray): resolution error with wrong number of
       // parameters. We cannot do this rigth now because of the
       // List constructor.
     }
+    compiler.enqueuer.resolution.registerStaticUse(constructor);
     useElement(node.send, constructor);
     return null;
   }
 
   TypeAnnotation getTypeAnnotationFromSend(Send send) {
     if (send.selector.asTypeAnnotation() !== null) {
       return send.selector;
     } else if (send.selector.asSend() !== null) {
       Send selector = send.selector;
       if (selector.receiver.asTypeAnnotation() !== null) {
@@ skipping 44 matching lines @@
 
   visitLiteralList(LiteralList node) {
     visit(node.elements);
   }
 
   visitConditional(Conditional node) {
     node.visitChildren(this);
   }
 
   visitStringInterpolation(StringInterpolation node) {
+    compiler.enqueuer.resolution.registerStaticUse(compiler.findHelper(
+        const SourceString("S")));
     node.visitChildren(this);
   }
 
   visitStringInterpolationPart(StringInterpolationPart node) {
     node.visitChildren(this);
   }
 
   visitBreakStatement(BreakStatement node) {
     TargetElement target;
     if (node.target === null) {
@@ skipping 768 matching lines @@
 
   TopScope(LibraryElement library) : super(null, library);
   Element lookup(SourceString name) {
     return library.find(name);
   }
 
   Element add(Element newElement) {
     throw "Cannot add an element in the top scope";
   }
 }