Add dart2js noInline and tryInline annotations to package:meta

There will be a follow-up change to remove NoInline from package:expect.

Change-Id: I6dc33241ea6d8b6a8994da6a8ec5295dab30f4da
Reviewed-on: https://dart-review.googlesource.com/17043
Reviewed-by: Sigmund Cherem <sigmund@google.com>

pkg/compiler/lib/src/common_elements.dart

@@ -1172,6 +1172,39 @@ class CommonElements {
     return _expectAssumeDynamicClass;
   }
 
+  static final Uri PACKAGE_META_DART2JS =
+      new Uri(scheme: 'package', path: 'meta/dart2js.dart');
+
+  bool _metaAnnotationChecked = false;
+  ClassEntity _metaNoInlineClass;
+  ClassEntity _metaTryInlineClass;
+
+  void _ensureMetaAnnotations() {
+    if (!_metaAnnotationChecked) {
+      _metaAnnotationChecked = true;
+      LibraryEntity library = _env.lookupLibrary(PACKAGE_META_DART2JS);
+      if (library != null) {
+        _metaNoInlineClass = _env.lookupClass(library, '_NoInline');
+        _metaTryInlineClass = _env.lookupClass(library, '_TryInline');
+        if (_metaNoInlineClass == null || _metaTryInlineClass == null) {
+          // This is not the package you're looking for.
+          _metaNoInlineClass = null;
+          _metaTryInlineClass = null;
+        }
+      }
+    }
+  }
+
+  ClassEntity get metaNoInlineClass {
+    _ensureMetaAnnotations();
+    return _metaNoInlineClass;
+  }
+
+  ClassEntity get metaTryInlineClass {
+    _ensureMetaAnnotations();
+    return _metaTryInlineClass;
+  }
+
   bool isForeign(MemberEntity element) => element.library == foreignLibrary;
 
   /// Returns `true` if the implementation of the 'operator ==' [function] is

pkg/compiler/lib/src/js_backend/annotations.dart

@@ -11,6 +11,10 @@ import '../elements/entities.dart';
 /// Returns `true` if inlining is disabled for [element].
 bool noInline(ElementEnvironment elementEnvironment,
     CommonElements commonElements, MemberEntity element) {
+  if (_hasAnnotation(
+      elementEnvironment, element, commonElements.metaNoInlineClass)) {
+    return true;
+  }
   if (_hasAnnotation(
       elementEnvironment, element, commonElements.expectNoInlineClass)) {
     // TODO(floitsch): restrict to elements from the test directory.
@@ -20,6 +24,16 @@ bool noInline(ElementEnvironment elementEnvironment,
       elementEnvironment, element, commonElements.noInlineClass);
 }
 
+/// Returns `true` if inlining is requested for [element].
+bool tryInline(ElementEnvironment elementEnvironment,
+    CommonElements commonElements, MemberEntity element) {
+  if (_hasAnnotation(
+      elementEnvironment, element, commonElements.metaTryInlineClass)) {
+    return true;
+  }
+  return false;
+}
+
 /// Returns `true` if parameter and returns types should be trusted for
 /// [element].
 bool trustTypeAnnotations(ElementEnvironment elementEnvironment,

pkg/compiler/lib/src/js_backend/backend.dart

@@ -1019,12 +1019,27 @@ class JavaScriptBackend {
       return;
     }
 
+    bool hasNoInline = false;
+    bool hasForceInline = false;
+
     if (element.isFunction || element.isConstructor) {
       if (optimizerHints.noInline(
           elementEnvironment, commonElements, element)) {
+        hasNoInline = true;
         inlineCache.markAsNonInlinable(element);
       }
+      if (optimizerHints.tryInline(
+          elementEnvironment, commonElements, element)) {
+        hasForceInline = true;
+        if (hasNoInline) {
+          reporter.reportErrorMessage(element, MessageKind.GENERIC,
+              {'text': '@tryInline must not be used with @noInline.'});
+        } else {
+          inlineCache.markAsMustInline(element);
         }
+      }
+    }
+
     if (element.isField) return;
     FunctionEntity method = element;
 
@@ -1033,8 +1048,7 @@ class JavaScriptBackend {
         !canLibraryUseNative(library)) {
       return;
     }
-    bool hasNoInline = false;
-    bool hasForceInline = false;
+
     bool hasNoThrows = false;
     bool hasNoSideEffects = false;
     for (ConstantValue constantValue

pkg/meta/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.1.4
+
+* Add `@dart2js.noInline` and `@dart2js.tryInline` annotations.
+
 ## 1.1.2
 
 * Rollback SDK constraint update for 2.0.0. No longer needed.

pkg/meta/lib/dart2js.dart

@@ -0,0 +1,42 @@
+// 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.
+
+/// Constants for use in metadata annotations to provide hints to dart2js.
+
+library meta_dart2js;
+
+/// An annotation for methods to request that dart2js does not inline the
+/// method.
+///
+///     import 'package:meta/dart2js.dart' as dart2js;
+///
+///     @dart2js.noInline
+///     String text() => 'A String of unusual size';
+///
+const _NoInline noInline = const _NoInline();
+
+/// An annotation for methods method to request that dart2js always inlines the
+/// method.
+///
+/// dart2js will attempt to inline the method regardless of its size. Even with
+/// this annotation, there are conditions that can prevent dart2js from inlining
+/// a method, including complex control flow.
+///
+///     import 'package:meta/dart2js.dart' as dart2js;
+///
+///     @dart2js.tryInline
+///     String bigMethod() {
+///       for (int i in "Hello".runes) print(i);
+///     }
+///
+/// It is an error to use both `@noInline` and `@tryInline`.
+const _TryInline tryInline = const _TryInline();
+
+class _NoInline {
+  const _NoInline();
+}
+
+class _TryInline {
+  const _TryInline();
+}

pkg/meta/pubspec.yaml

@@ -1,5 +1,5 @@
 name: meta
-version: 1.1.3
+version: 1.1.4
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/sdk/tree/master/pkg/meta
 description: >

tests/compiler/dart2js/meta_annotations2_test.dart

@@ -0,0 +1,66 @@
+// 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.
+
+// Functional test of 'noInline' annotation from package:meta/dart2js.dart.
+
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+import 'package:compiler/compiler_new.dart';
+import 'memory_compiler.dart';
+
+const MEMORY_SOURCE_FILES = const {
+  'main.dart': r'''
+        import 'package:meta/dart2js.dart';
+
+        @noInline
+        foo(y) => 49912344 + y;
+
+        class A {
+          var field;
+
+          @noInline
+          A([this.field = 4711]);
+
+          @noInline
+          static bar(x) => x + 123455;
+
+          @noInline
+          gee(x, y) => x + y + 81234512;
+        }
+
+        main() {
+          print(foo(23412));
+          print(A.bar(87654));
+          print(new A().gee(1337, 919182));
+          print(new A().field + 1);
+        }'''
+};
+
+void main() {
+  asyncTest(() async {
+    OutputCollector collector = new OutputCollector();
+    await runCompiler(
+        memorySourceFiles: MEMORY_SOURCE_FILES, outputProvider: collector);
+    // Simply check that the constants of the small functions are still in the
+    // output, and that we don't see the result of constant folding.
+    String jsOutput = collector.getOutput('', OutputType.js);
+
+    void has(String text) {
+      Expect.isTrue(jsOutput.contains(text), "output should contain '$text'");
+    }
+
+    void hasNot(String text) {
+      Expect.isFalse(
+          jsOutput.contains(text), "output must not contain '$text'");
+    }
+
+    has('49912344');
+    has('123455');
+    has('81234512');
+    hasNot('49935756');
+    hasNot('211109');
+    hasNot('82155031');
+    hasNot('4712');
+  });
+}

tests/compiler/dart2js/meta_annotations3_test.dart

@@ -0,0 +1,81 @@
+// 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.
+
+// Functional test of 'tryInline' annotation from package:meta/dart2js.dart.
+
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+import 'package:compiler/compiler_new.dart';
+import 'memory_compiler.dart';
+
+const MEMORY_SOURCE_FILES = const {
+  'main.dart': r'''
+        import 'package:meta/dart2js.dart';
+
+        monster1(u) {
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+        }
+
+        @tryInline
+        monster2(u) {
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+          print(u + 1000);
+        }
+
+        main() {
+          // large function used twice should not normally be inlined.
+          monster1(38000992);
+          monster1(38000993);
+          monster2(48000992);
+          monster2(48000993);
+        }'''
+};
+
+void main() {
+  asyncTest(() async {
+    OutputCollector collector = new OutputCollector();
+    await runCompiler(
+        memorySourceFiles: MEMORY_SOURCE_FILES, outputProvider: collector);
+    String jsOutput = collector.getOutput('', OutputType.js);
+
+    void has(String text) {
+      Expect.isTrue(jsOutput.contains(text), "output should contain '$text'");
+    }
+
+    void hasNot(String text) {
+      print(jsOutput);
+      Expect.isFalse(
+          jsOutput.contains(text), "output must not contain '$text'");
+    }
+
+    // Check that (u + 1000) from monster1 is not inlined and constant folded.
+    has('38000992');
+    has('38000993');
+    hasNot('38001992');
+    hasNot('38001993');
+
+    // Check that (u + 1000) from monster2 is inlined and constant folded.
+    hasNot('48000992');
+    hasNot('48000993');
+    has('48001992');
+    has('48001993');
+  });
+}

tests/compiler/dart2js/meta_annotations_test.dart

@@ -0,0 +1,69 @@
+// 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 'package:expect/expect.dart';
+import 'package:async_helper/async_helper.dart';
+import 'package:compiler/src/compiler.dart';
+import 'package:compiler/src/elements/elements.dart';
+import 'package:compiler/src/js_backend/annotations.dart' as optimizerHints;
+import 'package:compiler/src/world.dart' show ClosedWorld;
+import 'memory_compiler.dart';
+
+const Map MEMORY_SOURCE_FILES = const {
+  'main.dart': r"""
+import 'package:meta/dart2js.dart';
+
+int method(String arg) => arg.length;
+
+@noInline
+int methodNoInline(String arg) => arg.length;
+
+@tryInline
+int methodTryInline(String arg) => arg.length;
+
+
+void main(List<String> args) {
+  print(method(args[0]));
+  print(methodNoInline('bar'));
+  print(methodTryInline('bar'));
+}
+"""
+};
+
+main() {
+  asyncTest(() async {
+    CompilationResult result =
+        await runCompiler(memorySourceFiles: MEMORY_SOURCE_FILES);
+    Compiler compiler = result.compiler;
+    ClosedWorld closedWorld =
+        compiler.resolutionWorldBuilder.closedWorldForTesting;
+    Expect.isFalse(compiler.compilationFailed, 'Unsuccessful compilation');
+    Expect.isNotNull(closedWorld.commonElements.metaNoInlineClass,
+        'NoInlineClass is unresolved.');
+    Expect.isNotNull(closedWorld.commonElements.metaTryInlineClass,
+        'TryInlineClass is unresolved.');
+
+    void test(String name,
+        {bool expectNoInline: false, bool expectTryInline: false}) {
+      LibraryElement mainApp =
+          compiler.frontendStrategy.elementEnvironment.mainLibrary;
+      MethodElement method = mainApp.find(name);
+      Expect.isNotNull(method);
+      Expect.equals(
+          expectNoInline,
+          optimizerHints.noInline(closedWorld.elementEnvironment,
+              closedWorld.commonElements, method),
+          "Unexpected annotation of @noInline on '$method'.");
+      Expect.equals(
+          expectTryInline,
+          optimizerHints.tryInline(closedWorld.elementEnvironment,
+              closedWorld.commonElements, method),
+          "Unexpected annotation of @tryInline on '$method'.");
+    }
+
+    test('method');
+    test('methodNoInline', expectNoInline: true);
+    test('methodTryInline', expectTryInline: true);
+  });
+}