[dart2js] new-rti: Implement type literals

Emit type literals in the constant pool using recipes.

Change-Id: Ia5ea024b444596844e94afbe2a34ce33e8557604
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/107454
Commit-Queue: Stephen Adams <sra@google.com>
Reviewed-by: Mayank Patke <fishythefish@google.com>

pkg/compiler/lib/src/common_elements.dart

@@ -16,6 +16,7 @@ import 'inferrer/abstract_value_domain.dart';
 import 'js_backend/native_data.dart' show NativeBasicData;
 import 'js_model/locals.dart';
 import 'kernel/dart2js_target.dart';
+import 'options.dart';
 import 'universe/selector.dart' show Selector;
 
 /// The common elements and types in Dart.
@@ -482,6 +483,7 @@ abstract class CommonElements {
 
   FunctionEntity get findType;
   FunctionEntity get instanceType;
+  FunctionEntity get typeLiteralMaker;
   FieldEntity get rtiAsField;
   FieldEntity get rtiCheckField;
   FieldEntity get rtiIsField;
@@ -614,8 +616,9 @@ abstract class JCommonElements implements CommonElements {
 class CommonElementsImpl
     implements CommonElements, KCommonElements, JCommonElements {
   final ElementEnvironment _env;
+  final CompilerOptions _options;
 
-  CommonElementsImpl(this._env);
+  CommonElementsImpl(this._env, this._options);
 
   ClassEntity _objectClass;
   @override
@@ -1443,7 +1446,9 @@ class CommonElementsImpl
   ClassEntity _typeLiteralClass;
   @override
   ClassEntity get typeLiteralClass =>
-      _typeLiteralClass ??= _findHelperClass('TypeImpl');
+      _typeLiteralClass ??= _options.experimentNewRti
+          ? _findRtiClass('_Type')
+          : _findHelperClass('TypeImpl');
 
   ClassEntity _constMapLiteralClass;
   @override
@@ -1730,8 +1735,9 @@ class CommonElementsImpl
       _findHelperFunction('throwNoSuchMethod');
 
   @override
-  FunctionEntity get createRuntimeType =>
-      _findHelperFunction('createRuntimeType');
+  FunctionEntity get createRuntimeType => _options.experimentNewRti
+      ? _findRtiFunction('_createRuntimeType')
+      : _findHelperFunction('createRuntimeType');
 
   @override
   FunctionEntity get fallThroughError =>
@@ -1805,6 +1811,8 @@ class CommonElementsImpl
 
   // From dart:_rti
 
+  ClassEntity _findRtiClass(String name) => _findClass(rtiLibrary, name);
+
   FunctionEntity _findRtiFunction(String name) =>
       _findLibraryMember(rtiLibrary, name);
 
@@ -1817,6 +1825,11 @@ class CommonElementsImpl
   FunctionEntity get instanceType =>
       _instanceType ??= _findRtiFunction('instanceType');
 
+  FunctionEntity _typeLiteralMaker;
+  @override
+  FunctionEntity get typeLiteralMaker =>
+      _typeLiteralMaker ??= _findRtiFunction('typeLiteral');
+
   ClassEntity get _rtiImplClass => _findClass(rtiLibrary, 'Rti');
   FieldEntity _findRtiClassField(String name) =>
       _findClassMember(_rtiImplClass, name);

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

@@ -423,9 +423,12 @@ class BackendImpacts {
   BackendImpact _typeLiteral;
 
   BackendImpact get typeLiteral {
-    return _typeLiteral ??= new BackendImpact(
-        instantiatedClasses: [_commonElements.typeLiteralClass],
-        staticUses: [_commonElements.createRuntimeType]);
+    return _typeLiteral ??= new BackendImpact(instantiatedClasses: [
+      _commonElements.typeLiteralClass
+    ], staticUses: [
+      _commonElements.createRuntimeType,
+      if (_newRti) _commonElements.typeLiteralMaker,
+    ]);
   }
 
   BackendImpact _stackTraceInCatch;

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

@@ -182,12 +182,10 @@ class CodegenEnqueuerListener extends EnqueuerListener {
             helper, helper.parameterStructure.callStructure));
       }
       if (type.element == _commonElements.typeLiteralClass) {
-        // If we use a type literal in a constant, the compile time
-        // constant emitter will generate a call to the createRuntimeType
-        // helper so we register a use of that.
-        FunctionEntity helper = _commonElements.createRuntimeType;
-        impactBuilder.registerStaticUse(new StaticUse.staticInvoke(
-            helper, helper.parameterStructure.callStructure));
+        // If we use a type literal in a constant, the compile time constant
+        // emitter will generate a call to a helper so we register the impact
+        // that contains that call.
+        _impacts.typeLiteral.registerImpact(impactBuilder, _elementEnvironment);
       }
     }
   }

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

@@ -13,9 +13,11 @@ import '../js/js.dart' as jsAst;
 import '../js/js.dart' show js;
 import '../js_backend/field_analysis.dart';
 import '../js_emitter/code_emitter_task.dart';
+import '../js_model/type_recipe.dart' show TypeExpressionRecipe;
 import '../options.dart';
 import 'field_analysis.dart' show JFieldAnalysis;
 import 'runtime_types.dart';
+import 'runtime_types_new.dart' show RecipeEncoder;
 
 typedef jsAst.Expression _ConstantReferenceGenerator(ConstantValue constant);
 
@@ -205,6 +207,7 @@ class ConstantEmitter extends ModularConstantEmitter {
   final JElementEnvironment _elementEnvironment;
   final RuntimeTypesNeed _rtiNeed;
   final RuntimeTypesEncoder _rtiEncoder;
+  final RecipeEncoder _rtiRecipeEncoder;
   final JFieldAnalysis _fieldAnalysis;
   final Emitter _emitter;
   final _ConstantReferenceGenerator _constantReferenceGenerator;
@@ -219,6 +222,7 @@ class ConstantEmitter extends ModularConstantEmitter {
       this._elementEnvironment,
       this._rtiNeed,
       this._rtiEncoder,
+      this._rtiRecipeEncoder,
       this._fieldAnalysis,
       this._emitter,
       this._constantReferenceGenerator,
@@ -354,19 +358,34 @@ class ConstantEmitter extends ModularConstantEmitter {
   jsAst.Expression visitType(TypeConstantValue constant, [_]) {
     DartType type = constant.representedType.unaliased;
 
-    jsAst.Expression unexpected(TypeVariableType _variable) {
-      TypeVariableType variable = _variable;
-      throw failedAt(
-          NO_LOCATION_SPANNABLE,
-          "Unexpected type variable '${variable}'"
-          " in constant '${constant.toDartText()}'");
+    if (_options.experimentNewRti) {
+      assert(!type.containsTypeVariables);
+
+      jsAst.Expression recipe = _rtiRecipeEncoder.encodeGroundRecipe(
+          _emitter, TypeExpressionRecipe(type));
+
+      // Generate  `typeLiteral(recipe)`.
+
+      // TODO(sra): `typeLiteral(r)` calls `createRuntimeType(findType(r))`.
+      // Find a way to share the `findType` call with methods that also use the
+      // type.
+      return js('#(#)',
+          [getHelperProperty(_commonElements.typeLiteralMaker), recipe]);
+    } else {
+      jsAst.Expression unexpected(TypeVariableType _variable) {
+        TypeVariableType variable = _variable;
+        throw failedAt(
+            NO_LOCATION_SPANNABLE,
+            "Unexpected type variable '${variable}'"
+            " in constant '${constant.toDartText()}'");
+      }
+
+      jsAst.Expression rti =
+          _rtiEncoder.getTypeRepresentation(_emitter, type, unexpected);
+
+      return new jsAst.Call(
+          getHelperProperty(_commonElements.createRuntimeType), [rti]);
     }
-
-    jsAst.Expression rti =
-        _rtiEncoder.getTypeRepresentation(_emitter, type, unexpected);
-
-    return new jsAst.Call(
-        getHelperProperty(_commonElements.createRuntimeType), [rti]);
   }
 
   @override

pkg/compiler/lib/src/js_emitter/code_emitter_task.dart

@@ -90,6 +90,7 @@ class CodeEmitterTask extends CompilerTask {
           namer,
           closedWorld,
           codegen.rtiEncoder,
+          codegen.rtiRecipeEncoder,
           _backendStrategy.sourceInformationStrategy,
           this,
           _generateSourceMap);

pkg/compiler/lib/src/js_emitter/startup_emitter/emitter.dart

@@ -17,6 +17,7 @@ import '../../js/js.dart' as js;
 import '../../js_backend/constant_emitter.dart';
 import '../../js_backend/namer.dart';
 import '../../js_backend/runtime_types.dart';
+import '../../js_backend/runtime_types_new.dart' show RecipeEncoder;
 import '../../options.dart';
 import '../../universe/codegen_world_builder.dart' show CodegenWorld;
 import '../../world.dart' show JClosedWorld;
@@ -143,6 +144,7 @@ class EmitterImpl extends ModularEmitterBase implements Emitter {
   final DiagnosticReporter _reporter;
   final JClosedWorld _closedWorld;
   final RuntimeTypesEncoder _rtiEncoder;
+  final RecipeEncoder _rtiRecipeEncoder;
   final CompilerTask _task;
   ModelEmitter _emitter;
 
@@ -157,6 +159,7 @@ class EmitterImpl extends ModularEmitterBase implements Emitter {
       Namer namer,
       this._closedWorld,
       this._rtiEncoder,
+      this._rtiRecipeEncoder,
       SourceInformationStrategy sourceInformationStrategy,
       this._task,
       bool shouldGenerateSourceMap)
@@ -172,6 +175,7 @@ class EmitterImpl extends ModularEmitterBase implements Emitter {
         this,
         sourceInformationStrategy,
         _rtiEncoder,
+        _rtiRecipeEncoder,
         shouldGenerateSourceMap);
   }
 

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

@@ -49,6 +49,7 @@ import '../../js_backend/js_backend.dart'
     show Namer, ConstantEmitter, StringBackedName;
 import '../../js_backend/js_interop_analysis.dart' as jsInteropAnalysis;
 import '../../js_backend/runtime_types.dart';
+import '../../js_backend/runtime_types_new.dart' show RecipeEncoder;
 import '../../options.dart';
 import '../../universe/codegen_world_builder.dart' show CodegenWorld;
 import '../../world.dart';
@@ -99,6 +100,7 @@ class ModelEmitter {
       this._emitter,
       this._sourceInformationStrategy,
       RuntimeTypesEncoder rtiEncoder,
+      RecipeEncoder rtiRecipeEncoder,
       this._shouldGenerateSourceMap)
       : _constantOrdering = new ConstantOrdering(_closedWorld.sorter) {
     this._constantEmitter = new ConstantEmitter(
@@ -107,6 +109,7 @@ class ModelEmitter {
         _closedWorld.elementEnvironment,
         _closedWorld.rtiNeed,
         rtiEncoder,
+        rtiRecipeEncoder,
         _closedWorld.fieldAnalysis,
         _emitter,
         this.generateConstantReference,

pkg/compiler/lib/src/js_model/element_map_impl.dart

@@ -138,7 +138,8 @@ class JsKernelToElementMap implements JsToElementMap, IrToElementMap {
       AnnotationsData annotations)
       : this.options = _elementMap.options {
     _elementEnvironment = new JsElementEnvironment(this);
-    _commonElements = new CommonElementsImpl(_elementEnvironment);
+    _commonElements =
+        new CommonElementsImpl(_elementEnvironment, _elementMap.options);
     _constantEnvironment = new JsConstantEnvironment(this, environment);
     _typeConverter = new DartTypeConverter(this);
     _types = new KernelDartTypes(this);
@@ -317,7 +318,7 @@ class JsKernelToElementMap implements JsToElementMap, IrToElementMap {
   JsKernelToElementMap.readFromDataSource(this.options, this.reporter,
       Environment environment, ir.Component component, DataSource source) {
     _elementEnvironment = new JsElementEnvironment(this);
-    _commonElements = new CommonElementsImpl(_elementEnvironment);
+    _commonElements = new CommonElementsImpl(_elementEnvironment, options);
     _constantEnvironment = new JsConstantEnvironment(this, environment);
     _typeConverter = new DartTypeConverter(this);
     _types = new KernelDartTypes(this);

pkg/compiler/lib/src/kernel/element_map_impl.dart

@@ -122,7 +122,7 @@ class KernelToElementMapImpl implements KernelToElementMap, IrToElementMap {
   KernelToElementMapImpl(
       this.reporter, this._environment, this._frontendStrategy, this.options) {
     _elementEnvironment = new KernelElementEnvironment(this);
-    _commonElements = new CommonElementsImpl(_elementEnvironment);
+    _commonElements = new CommonElementsImpl(_elementEnvironment, options);
     _constantEnvironment = new KernelConstantEnvironment(this, _environment);
     _typeConverter = new DartTypeConverter(this);
     _types = new KernelDartTypes(this);

sdk/lib/_internal/js_runtime/lib/js_helper.dart

@@ -59,7 +59,7 @@ import 'dart:_js_names'
         unmangleGlobalNameIfPreservedAnyways,
         unmangleAllIdentifiersIfPreservedAnyways;
 
-import 'dart:_rti' as newRti show getRuntimeType;
+import 'dart:_rti' as newRti show createRuntimeType, getRuntimeType;
 
 part 'annotations.dart';
 part 'constant_map.dart';

sdk/lib/_internal/js_runtime/lib/rti.dart

@@ -87,7 +87,12 @@ class Rti {
   dynamic _precomputed4;
 
   // The Type object corresponding to this Rti.
-  Type _typeCache;
+  Object _cachedRuntimeType;
+  static _Type _getCachedRuntimeType(Rti rti) =>
+      JS('_Type|Null', '#', rti._cachedRuntimeType);
+  static void _setCachedRuntimeType(Rti rti, _Type type) {
+    rti._cachedRuntimeType = type;
+  }
 
   /// The kind of Rti `this` is, one of the kindXXX constants below.
   ///
@@ -280,7 +285,43 @@ Rti _instanceTypeFromConstructor(constructor) {
 }
 
 Type getRuntimeType(object) {
-  throw UnimplementedError('getRuntimeType');
+  Rti rti = instanceType(object);
+  return _createRuntimeType(rti);
+}
+
+/// Called from generated code.
+Type _createRuntimeType(Rti rti) {
+  _Type type = Rti._getCachedRuntimeType(rti);
+  if (type != null) return type;
+  // TODO(https://github.com/dart-lang/language/issues/428) For NNBD transition,
+  // canonicalization may be needed. It might be possible to generate a
+  // star-free recipe from the canonical recipe and evaluate that.
+  type = _Type(rti);
+  Rti._setCachedRuntimeType(rti, type);
+  return type;
+}
+
+/// Called from generated code in the constant pool.
+Type typeLiteral(String recipe) {
+  return _createRuntimeType(findType(recipe));
+}
+
+/// Implementation of [Type] based on Rti.
+class _Type implements Type {
+  final Rti _rti;
+  int _hashCode;
+
+  _Type(this._rti);
+
+  int get hashCode => _hashCode ??= Rti._getCanonicalRecipe(_rti).hashCode;
+
+  @pragma('dart2js:noInline')
+  bool operator ==(other) {
+    return (other is _Type) && identical(_rti, other._rti);
+  }
+
+  @override
+  String toString() => _rtiToString(_rti, null);
 }
 
 /// Called from generated code.

tests/compiler/dart2js_extra/rti/runtime_type_2_test.dart

@@ -0,0 +1,22 @@
+// Copyright (c) 2019, 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.
+//
+// dart2jsOptions=--experiment-new-rti --no-minify
+
+import "package:expect/expect.dart";
+
+@pragma('dart2js:noInline')
+Type grab<T>() => T;
+
+@pragma('dart2js:noInline')
+Type grabList<T>() => grab<List<T>>();
+
+main() {
+  Expect.equals('int', grab<int>().toString());
+  Expect.identical(int, grab<int>());
+
+  Expect.equals('List<int>', grabList<int>().toString());
+
+  Expect.equals('List<dynamic>', (List).toString());
+}