dart2js: emit tear-offs in new emitter.

pkg/compiler/lib/src/js_emitter/new_emitter/model_emitter.dart

Index: pkg/compiler/lib/src/js_emitter/new_emitter/model_emitter.dart
diff --git a/pkg/compiler/lib/src/js_emitter/new_emitter/model_emitter.dart b/pkg/compiler/lib/src/js_emitter/new_emitter/model_emitter.dart
index d13108a3a767d5860f8f4e4d3794776291687681..a537e5c12b21b002d2730c13b41e2de07bf95f83 100644
--- a/pkg/compiler/lib/src/js_emitter/new_emitter/model_emitter.dart
+++ b/pkg/compiler/lib/src/js_emitter/new_emitter/model_emitter.dart
@@ -395,19 +395,12 @@ class ModelEmitter {
     } else {
       elements.add(_generateConstructor(cls));
     }
-    Iterable<Method> methods = cls.methods.expand((Method method) {
-      // TODO(floitsch): can there be anything else than a DartMethod?
-      if (method is DartMethod) {
-        return [method]..addAll(method.parameterStubs);
-      } else {
-        return [method];
-      }
-    });
+    Iterable<Method> methods = cls.methods;
     Iterable<Method> isChecks = cls.isChecks;
     Iterable<Method> gettersSetters = _generateGettersSetters(cls);
     Iterable<Method> allMethods =
         [methods, isChecks, gettersSetters].expand((x) => x);
-    elements.addAll(allMethods.expand((e) => [js.string(e.name), e.code]));
+    elements.addAll(allMethods.expand(emitInstanceMethod));
     return unparse(compiler, new js.ArrayInitializer(elements));
   }
 
@@ -416,6 +409,51 @@ class ModelEmitter {
     return unparse(compiler, field.code);
   }
 
+  static final String tearOffBoilerplate = """
+function(prototype, tearOffDescriptor) {
+  prototype[tearOffDescriptor[0]] = tearOffDescriptor[1];
+  for (var i = 3; i < tearOffDescriptor.length; i += 3) {
+    // Copy over the parameter stubs.
+    prototype[tearOffDescriptor[i]] = tearOffDescriptor[i + 2];
+  }
+  // Build the functions map.
+  var funcs = Object.create(null);
+  for (var i = 3; i < tearOffDescriptor.length; i += 3) {
+    // Copy over the parameter stubs.
+    prototype[tearOffDescriptor[i]] = tearOffDescriptor[i + 2];
+  }
+  
+}
+""";
+
+  Iterable<js.Expression> emitInstanceMethod(Method method) {
+
+    List<js.Expression> makeNameCodePair(Method method) {
+      return [js.string(method.name), method.code];
+    }
+
+    List<js.Expression> makeNameCallNameCodeTriplet(ParameterStubMethod stub) {
+      js.Expression callName = stub.callName == null
+          ? new js.LiteralNull()
+          : js.string(stub.callName);
+      return [js.string(stub.name), callName, method.code];
+    }
+
+    if (method is DartMethod) {
+      if (method.needsTearOff) {
+        var data = makeNameCodePair(method);
+        data.add(js.string(method.tearOffName));
+        data.addAll(method.parameterStubs.expand(makeNameCallNameCodeTriplet));
+        return [new js.ArrayInitializer(data)];
+      } else {
+        // TODO(floitsch): not the most efficient way...
+        return ([method]..addAll(method.parameterStubs)).expand(makeNameCodePair);

[zarah, 2015/01/30 14:24:23]

long line.

+      }
+    } else {
+      return makeNameCodePair(method);
+    }
+  }
+
   Iterable<js.Expression> emitStaticMethod(StaticMethod method) {
     js.Expression holderIndex = js.number(method.holder.index);
     List<js.Expression> output = <js.Expression>[];