Add LimitedBinaryPrinter, tests and switch incremental generator to it.

pkg/front_end/test/incremental_kernel_generator_test.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:async';
 
 import 'package:front_end/compiler_options.dart';
 import 'package:front_end/incremental_kernel_generator.dart';
 import 'package:front_end/memory_file_system.dart';
 import 'package:front_end/src/incremental/byte_store.dart';
+import 'package:front_end/src/incremental/limited_ast_to_binary.dart';
+import 'package:front_end/src/incremental_kernel_generator_impl.dart';
 import 'package:kernel/ast.dart';
+import 'package:kernel/binary/ast_from_binary.dart';
 import 'package:kernel/text/ast_to_text.dart';
+import 'package:kernel/verifier.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'src/incremental/mock_sdk.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(IncrementalKernelGeneratorTest);
   });
 }
@@ skipping 233 matching lines @@
         _getLibraryText(library),
         r'''
 library;
 import self as self;
 import "dart:core" as core;
 
 static field (core::String) → core::int f;
 ''');
   }
 
+  test_limited_ast_to_binary() async {
+    writeFile('/test/.packages', 'test:lib/');
+    String aPath = '/test/lib/a.dart';
+    String bPath = '/test/lib/b.dart';
+    writeFile(
+        aPath,
+        r'''
+int topField = 0;
+int get topGetter => 0;
+int topFunction({p}) => 0;
+        
+class A {
+  static int staticField;
+  static int get staticGetter => 0;
+  static int staticMethod() => 0;
+
+  int instanceField;
+  int get instanceGetter => 0;
+  int instanceMethod() => 0;
+  
+  A();
+  A.named();
+}
+''');
+    Uri bUri = writeFile(
+        bPath,
+        r'''
+import 'a.dart';
+
+class B extends A {
+  B() : super();
+  B.named() : super.named();
+  
+  void foo() {
+    super.instanceMethod();
+    instanceMethod();
+  }
+  
+  int instanceMethod() => 0;
+}
+
+main() {
+  topField;
+  topField = 0;
+  var v1 = topGetter;
+  var v2 = topFunction(p: 0);
+
+  A.staticField;
+  A.staticField = 0;
+  var v3 = A.staticGetter;
+  var v4 = A.staticMethod();
+
+  var a = new A();
+  a.instanceField;
+  a.instanceField = 0;
+  var v5 = a.instanceGetter;
+  var v6 = a.instanceMethod();
+}
+''');
+
+    Program initialProgram = await getInitialState(bUri);
+
+    String initialKernelText;
+    List<int> bytes;
+    {
+      Library initialLibrary = _getLibrary(initialProgram, bUri);
+      initialKernelText = _getLibraryText(initialLibrary);
+
+      var byteSink = new ByteSink();
+      var printer = new LimitedBinaryPrinter(
+          byteSink, (library) => library.importUri == bUri);
+      printer.writeProgramFile(initialProgram);
+      bytes = byteSink.builder.takeBytes();
+
+      // Remove b.dart from the initial program.
+      // So, the program is now ready for re-adding the library.
+      initialProgram.libraries.remove(initialLibrary);
+      initialProgram.root.removeChild(initialLibrary.importUri.toString());
+    }
+
+    // Load b.dart from bytes using the initial name root, so that
+    // serialized canonical names can be linked to corresponding nodes.
+    Library loadedLibrary;
+    {
+      var programForLoading = new Program(nameRoot: initialProgram.root);
+      var reader = new BinaryBuilder(bytes);
+      reader.readProgram(programForLoading);
+      loadedLibrary = _getLibrary(programForLoading, bUri);
+    }
+
+    // Add the library into the initial program.
+    initialProgram.libraries.add(loadedLibrary);

[Siggi Cherem (dart-lang), 2017/05/23 20:54:51]

nit: either rename initialProgram or add a second variable for the program after
you start modifying it.

[scheglov, 2017/05/23 21:54:43]

I renamed it to just "program".

+    loadedLibrary.parent = initialProgram;
+
+    // The loaded library has the same text.
+    expect(_getLibraryText(loadedLibrary), initialKernelText);
+
+    // The program with re-added library passes verification.

[Siggi Cherem (dart-lang), 2017/05/23 20:54:51]

I'd delete this and the comment above, I think the code reads similar to this
sentence, especially if we rename `initialProgram` or add a second varaible name
for it (e.g. `modifiedProgram`)

[scheglov, 2017/05/23 21:54:43]

OK, I removed both comments.

A second variable name does not work, we have one instance, it does not seem
useful to have aliases for it.

+    verifyProgram(initialProgram);
+  }
+
   test_updateEntryPoint() async {
     writeFile('/test/.packages', 'test:lib/');
     String path = '/test/lib/test.dart';
     Uri uri = writeFile(
         path,
         r'''
 main() {
   var v = 1;
 }
 ''');
@@ skipping 178 matching lines @@
     throw fail('No library found with URI "$uri"');
   }
 
   String _getLibraryText(Library library) {
     StringBuffer buffer = new StringBuffer();
     new Printer(buffer, syntheticNames: new NameSystem())
         .writeLibraryFile(library);
     return buffer.toString();
   }
 }