Make TypeMask an interface and start hiding implementation details of FlatTypeMask.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.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 js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 2236 matching lines @@
     // Keep track of the JavaScript names we've already added so we
     // do not introduce duplicates (bad for code size).
     Map<String, Selector> addedJsNames = new Map<String, Selector>();
 
     void addNoSuchMethodHandlers(SourceString ignore, Set<Selector> selectors) {
       // Cache the object class and type.
       ClassElement objectClass = compiler.objectClass;
       DartType objectType = objectClass.computeType(compiler);
 
       for (Selector selector in selectors) {
-        // Introduce a helper function that determines if the given
-        // class has a member that matches the current name and
-        // selector (grabbed from the scope).
-        bool hasMatchingMember(ClassElement holder) {
-          Element element = holder.lookupSelector(selector);
-          return (element != null)
-              ? selector.applies(element, compiler)
-              : false;
-        }
-
         // If the selector is typed, we check to see if that type may
         // have a user-defined noSuchMethod implementation. If not, we
         // skip the selector altogether.
 
-        // TODO(kasperl): This shouldn't depend on the internals of
-        // the type mask. Move more of this code to the type mask.
-        ClassElement receiverClass = objectClass;
         TypeMask mask = selector.mask;
-        if (mask != null) {
-          // If the mask is empty it doesn't contain a noSuchMethod
-          // handler -- not even if it is nullable.
-          if (mask.isEmpty) continue;
-          receiverClass = mask.base.element;
+        if (mask == null) {
+          mask = new TypeMask.subclass(compiler.objectClass.rawType);
         }
 
-        // If the receiver class is guaranteed to have a member that
+        // If the receiver is guaranteed to have a member that
         // matches what we're looking for, there's no need to
         // introduce a noSuchMethod handler. It will never be called.
         //
         // As an example, consider this class hierarchy:
         //
         //                   A    <-- noSuchMethod
         //                  / \
         //                 C   B  <-- foo
         //
         // If we know we're calling foo on an object of type B we
         // don't have to worry about the noSuchMethod method in A
         // because objects of type B implement foo. On the other hand,
         // if we end up calling foo on something of type C we have to
         // add a handler for it.
-        if (hasMatchingMember(receiverClass)) continue;
 
         // If the holders of all user-defined noSuchMethod
         // implementations that might be applicable to the receiver
         // type have a matching member for the current name and
         // selector, we avoid introducing a noSuchMethod handler.
         //
         // As an example, consider this class hierarchy:
         //
         //                       A    <-- foo
         //                      / \
         //   noSuchMethod -->  B   C  <-- bar
         //                     |   |
         //                     C   D  <-- noSuchMethod
         //
         // When calling foo on an object of type A, we know that the
         // implementations of noSuchMethod are in the classes B and D
         // that also (indirectly) implement foo, so we do not need a
         // handler for it.
         //
         // If we're calling bar on an object of type D, we don't need
         // the handler either because all objects of type D implement
         // bar through inheritance.
         //
         // If we're calling bar on an object of type A we do need the
         // handler because we may have to call B.noSuchMethod since B
         // does not implement bar.
-        Iterable<ClassElement> holders =
-            compiler.world.locateNoSuchMethodHolders(selector);
-        if (holders.every(hasMatchingMember)) continue;
+        if (mask.willHit(selector, compiler)) continue;
         String jsName = namer.invocationMirrorInternalName(selector);
         addedJsNames[jsName] = selector;
       }
     }
 
     compiler.codegenWorld.invokedNames.forEach(addNoSuchMethodHandlers);
     compiler.codegenWorld.invokedGetters.forEach(addNoSuchMethodHandlers);
     compiler.codegenWorld.invokedSetters.forEach(addNoSuchMethodHandlers);
 
     // Set flag used by generateMethod helper below.  If we have very few
@@ skipping 737 matching lines @@
 """;
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;