dart2js: Inline across deferred output units if that leads to reduced size.

tests/compiler/dart2js/deferred_inline_restrictions_test.dart

 // Copyright (c) 2014, 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.
 
-// Test that the additional runtime type support is output to the right
-// Files when using deferred loading.
+// Test that we do not accidentially leak code from deferred libraries but do
+// allow inlining of empty functions and from main.
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 import 'memory_source_file_helper.dart';
 import "dart:async";
 
 import 'package:compiler/src/dart2jslib.dart'
        as dart2js;
 
 class MemoryOutputSink extends EventSink<String> {
@@ skipping 31 matching lines @@
                                    handler.diagnosticHandler,
                                    libraryRoot,
                                    packageRoot,
                                    [],
                                    {});
   asyncTest(() => compiler.run(Uri.parse('memory:main.dart')).then((_) {
     lookupLibrary(name) {
       return compiler.libraryLoader.lookupLibrary(Uri.parse(name));
     }
 
-    var main = compiler.mainApp.find(dart2js.Compiler.MAIN);
-    Expect.isNotNull(main, "Could not find 'main'");
-    compiler.deferredLoadTask.onResolutionComplete(main);
-
     var outputUnitForElement = compiler.deferredLoadTask.outputUnitForElement;
 
     var lib1 = lookupLibrary("memory:lib1.dart");
-    var foo1 = lib1.find("finalVar");
-    var ou_lib1 = outputUnitForElement(foo1);
+    var inlineMeAway = lib1.find("inlineMeAway");
+    var ou_lib1 = outputUnitForElement(inlineMeAway);
+
+    var lib3 = lookupLibrary("memory:lib3.dart");
+    var sameContextInline = lib3.find("sameContextInline");
+    var ou_lib3 = outputUnitForElement(sameContextInline);
+
+    // Test that we actually got differnt output units.
+    Expect.notEquals(ou_lib1.name, ou_lib3.name);
 
     String mainOutput = outputs["main.js"].mem.toString();
     String lib1Output = outputs["out_${ou_lib1.name}.part.js"].mem.toString();
-    // Test that the deferred globals are not inlined into the main file.
-    RegExp re1 = new RegExp(r"= .string1");
-    RegExp re2 = new RegExp(r"= .string2");
-    Expect.isTrue(re1.hasMatch(lib1Output));
+    String lib3Output = outputs["out_${ou_lib3.name}.part.js"].mem.toString();
+
+    RegExp re1 = new RegExp(r"inlined as empty");
+    RegExp re2 = new RegExp(r"inlined from main");
+    RegExp re3 = new RegExp(r"inlined from lib1");
+    RegExp re4 = new RegExp(r"inline same context");
+
+    // Test that inlineMeAway was inlined and its argument thus dropped.
+    Expect.isFalse(re1.hasMatch(mainOutput));
+
+    // Test that inlineFromMain was inlined and thus the string moved to lib1.
+    Expect.isFalse(re2.hasMatch(mainOutput));
     Expect.isTrue(re2.hasMatch(lib1Output));
-    Expect.isFalse(re1.hasMatch(mainOutput));
-    Expect.isFalse(re2.hasMatch(mainOutput));
+
+    // Test that inlineFromLib1 was not inlined into main.
+    Expect.isFalse(re3.hasMatch(mainOutput));
+    Expect.isTrue(re3.hasMatch(lib1Output));
+
+    // Test that inlineSameContext was inlined into lib1.
+    Expect.isFalse(re4.hasMatch(lib3Output));
+    Expect.isTrue(re4.hasMatch(lib1Output));
   }));
 }
 
-// Make sure that deferred constants are not inlined into the main hunk.
+// Make sure that empty functions are inlined and that functions from
+// main also are inlined (assuming normal heuristics).
 const Map MEMORY_SOURCE_FILES = const {"main.dart": """
 import "dart:async";
 
 import 'lib1.dart' deferred as lib1;
+import 'lib2.dart' deferred as lib2;
+
+inlineFromMain(x) => "inlined from main" + x;
 
 void main() {
   lib1.loadLibrary().then((_) {
-    print(lib1.finalVar);
-    print(lib1.globalVar);
-    lib1.globalVar = "foobar";
-    print(lib1.globalVar);
+    lib2.loadLibrary().then((_) {
+      lib1.test();
+      lib2.test();
+      print(lib1.inlineMeAway("inlined as empty"));
+      print(lib1.inlineFromLib1("should stay"));
+    });
   });
 }
 """, "lib1.dart": """
 import "main.dart" as main;
-final finalVar = "string1";
-var globalVar = "string2";
+import "lib3.dart" as lib3;
+
+inlineMeAway(x) {}
+
+inlineFromLib1(x) => "inlined from lib1" + x;
+
+test() {
+  print(main.inlineFromMain("should be inlined"));
+  print(lib3.sameContextInline("should be inlined"));
+}
+""", "lib2.dart": """
+import "lib3.dart" as lib3;
+
+test() {
+  print(lib3.sameContextInline("should be inlined"));
+}
+""", "lib3.dart": """
+sameContextInline(x) => "inline same context" + x;
 """};