[dart2js] initial steps to prepare codegen and ssa/codegen.dart for migration

This removes most unmigrated dependencies, only 4 remain. 3 in the same ssa
folder, and one to js_backend/type_reference.dart

Change-Id: I15596d6f5a915c5043f87861ac1a9fa4327f8c4a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/265680
Reviewed-by: Mayank Patke <fishythefish@google.com>

pkg/compiler/lib/src/common/codegen.dart

@@ -18,7 +18,7 @@ import '../inferrer/abstract_value_domain.dart';
 import '../inferrer/types.dart';
 import '../io/source_information.dart';
 import '../js/js.dart' as js;
-import '../js_backend/backend.dart';
+import '../js_backend/codegen_inputs.dart';
 import '../js_backend/namer.dart';
 import '../js_backend/deferred_holder_expression.dart'
     show DeferredHolderExpression;
@@ -38,6 +38,8 @@ import '../util/enumset.dart';
 import '../util/util.dart';
 import '../world.dart';
 
+import 'codegen_interfaces.dart' as interfaces;
+
 class CodegenImpact extends WorldImpact {
   const CodegenImpact();
 
@@ -322,7 +324,7 @@ class _CodegenImpact extends WorldImpactBuilderImpl implements CodegenImpact {
 
 // TODO(johnniwinther): Split this class into interface and implementation.
 // TODO(johnniwinther): Move this implementation to the JS backend.
-class CodegenRegistry {
+class CodegenRegistry implements interfaces.CodegenRegistry {
   final ElementEnvironment _elementEnvironment;
   final MemberEntity _currentElement;
   final _CodegenImpact _worldImpact;
@@ -336,81 +338,100 @@ class CodegenRegistry {
   String toString() => 'CodegenRegistry for $_currentElement';
 
   @deprecated
+  @override
   void registerInstantiatedClass(ClassEntity element) {
     registerInstantiation(_elementEnvironment.getRawType(element));
   }
 
+  @override
   void registerStaticUse(StaticUse staticUse) {
     _worldImpact.registerStaticUse(staticUse);
   }
 
+  @override
   void registerDynamicUse(DynamicUse dynamicUse) {
     _worldImpact.registerDynamicUse(dynamicUse);
   }
 
+  @override
   void registerTypeUse(TypeUse typeUse) {
     _worldImpact.registerTypeUse(typeUse);
   }
 
+  @override
   void registerConstantUse(ConstantUse constantUse) {
     _worldImpact.registerConstantUse(constantUse);
   }
 
+  @override
   void registerTypeVariableBoundsSubtypeCheck(
       DartType subtype, DartType supertype) {
     _worldImpact.registerTypeVariableBoundsSubtypeCheck(subtype, supertype);
   }
 
+  @override
   void registerInstantiatedClosure(FunctionEntity element) {
     _worldImpact.registerStaticUse(StaticUse.callMethod(element));
   }
 
+  @override
   void registerConstSymbol(String name) {
     _worldImpact.registerConstSymbol(name);
   }
 
+  @override
   void registerSpecializedGetInterceptor(Set<ClassEntity> classes) {
     _worldImpact.registerSpecializedGetInterceptor(classes);
   }
 
+  @override
   void registerOneShotInterceptor(Selector selector) {
     _worldImpact.registerOneShotInterceptor(selector);
   }
 
+  @override
   void registerUseInterceptor() {
     _worldImpact.registerUseInterceptor();
   }
 
+  @override
   void registerInstantiation(InterfaceType type) {
     registerTypeUse(TypeUse.instantiation(type));
   }
 
+  @override
   void registerAsyncMarker(AsyncMarker asyncMarker) {
     _worldImpact.registerAsyncMarker(asyncMarker);
   }
 
+  @override
   void registerGenericInstantiation(GenericInstantiation instantiation) {
     _worldImpact.registerGenericInstantiation(instantiation);
   }
 
+  @override
   void registerNativeBehavior(NativeBehavior nativeBehavior) {
     _worldImpact.registerNativeBehavior(nativeBehavior);
   }
 
+  @override
   void registerNativeMethod(FunctionEntity function) {
     _worldImpact.registerNativeMethod(function);
   }
 
-  void registerModularName(ModularName name) {
+  @override
+  void registerModularName(covariant ModularName name) {
     _names ??= [];
     _names.add(name);
   }
 
-  void registerModularExpression(ModularExpression expression) {
+  @override
+  void registerModularExpression(covariant ModularExpression expression) {
     _expressions ??= [];
     _expressions.add(expression);
   }
 
+  @override
   CodegenResult close(js.Fun code) {
     return CodegenResult(
         code, _worldImpact, _names ?? const [], _expressions ?? const []);
@@ -469,7 +490,7 @@ class DeserializedCodegenResults extends CodegenResults {
 }
 
 /// The code generation result for a single [MemberEntity].
-class CodegenResult {
+class CodegenResult implements interfaces.CodegenResult {
   static const String tag = 'codegen-result';
 
   final js.Fun code;
@@ -614,7 +635,8 @@ enum ModularNameKind {
   asName,
 }
 
-class ModularName extends js.Name implements js.AstContainer {
+class ModularName extends js.Name
+    implements js.AstContainer, interfaces.ModularName {
   static const String tag = 'modular-name';
 
   final ModularNameKind kind;
@@ -864,7 +886,7 @@ enum ModularExpressionKind {
 }
 
 class ModularExpression extends js.DeferredExpression
-    implements js.AstContainer {
+    implements js.AstContainer, interfaces.ModularExpression {
   static const String tag = 'modular-expression';
 
   final ModularExpressionKind kind;

pkg/compiler/lib/src/common/codegen_interfaces.dart

@@ -0,0 +1,59 @@
+// Copyright (c) 2022, 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 '../js/js.dart' as js;
+import '../elements/entities.dart';
+import '../elements/types.dart' show DartType, InterfaceType;
+import '../native/behavior.dart';
+import '../universe/feature.dart';
+import '../universe/selector.dart';
+import '../universe/use.dart' show ConstantUse, DynamicUse, StaticUse, TypeUse;
+
+abstract class CodegenRegistry {
+  @deprecated
+  void registerInstantiatedClass(ClassEntity element);
+
+  void registerStaticUse(StaticUse staticUse);
+
+  void registerDynamicUse(DynamicUse dynamicUse);
+
+  void registerTypeUse(TypeUse typeUse);
+
+  void registerConstantUse(ConstantUse constantUse);
+
+  void registerTypeVariableBoundsSubtypeCheck(
+      DartType subtype, DartType supertype);
+
+  void registerInstantiatedClosure(FunctionEntity element);
+
+  void registerConstSymbol(String name);
+
+  void registerSpecializedGetInterceptor(Set<ClassEntity> classes);
+
+  void registerOneShotInterceptor(Selector selector);
+
+  void registerUseInterceptor();
+
+  void registerInstantiation(InterfaceType type);
+
+  void registerAsyncMarker(AsyncMarker asyncMarker);
+
+  void registerGenericInstantiation(GenericInstantiation instantiation);
+
+  void registerNativeBehavior(NativeBehavior nativeBehavior);
+
+  void registerNativeMethod(FunctionEntity function);
+
+  void registerModularName(ModularName name);
+
+  void registerModularExpression(ModularExpression expression);
+
+  CodegenResult close(js.Fun code);
+}
+
+abstract class ModularExpression {}
+
+abstract class ModularName {}
+
+abstract class CodegenResult {}

pkg/compiler/lib/src/compiler.dart

@@ -52,7 +52,7 @@ import 'inferrer_experimental/typemasks/masks.dart' as experimentalInferrer
     show TypeMaskStrategy;
 import 'inferrer/wrapped.dart' show WrappedAbstractValueStrategy;
 import 'ir/modular.dart';
-import 'js_backend/backend.dart' show CodegenInputs;
+import 'js_backend/codegen_inputs.dart' show CodegenInputs;
 import 'js_backend/enqueuer.dart';
 import 'js_backend/inferred_data.dart';
 import 'js_model/js_strategy.dart';

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

@@ -11,12 +11,8 @@ import '../common/codegen.dart';
 import '../elements/entities.dart';
 import '../inferrer/types.dart';
 import '../js_model/elements.dart';
-import '../tracer.dart';
 import 'annotations.dart';
-import 'checked_mode_helpers.dart';
-import 'namer.dart';
-import 'runtime_types_codegen.dart';
-import 'runtime_types_new.dart';
+import 'codegen_inputs.dart';
 
 abstract class FunctionCompiler {
   void initialize(
@@ -239,15 +235,3 @@ class FunctionInlineCache {
     return _annotationsData.hasTryInline(element);
   }
 }
-
-/// Holds resources only used during code generation.
-class CodegenInputs {
-  final CheckedModeHelpers checkedModeHelpers = CheckedModeHelpers();
-  final RuntimeTypesSubstitutions rtiSubstitutions;
-  final RecipeEncoder rtiRecipeEncoder;
-  final Tracer tracer;
-  final FixedNames fixedNames;
-
-  CodegenInputs(this.rtiSubstitutions, this.rtiRecipeEncoder, this.tracer,
-      this.fixedNames);
-}

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

@@ -0,0 +1,21 @@
+// Copyright (c) 2012, 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 '../tracer_interfaces.dart';
+import 'checked_mode_helpers.dart';
+import 'namer_migrated.dart';
+import 'runtime_types_codegen.dart';
+import 'runtime_types_new_interfaces.dart';
+
+/// Holds resources only used during code generation.
+class CodegenInputs {
+  final CheckedModeHelpers checkedModeHelpers = CheckedModeHelpers();
+  final RuntimeTypesSubstitutions rtiSubstitutions;
+  final RecipeEncoder rtiRecipeEncoder;
+  final Tracer tracer;
+  final FixedNames fixedNames;
+
+  CodegenInputs(this.rtiSubstitutions, this.rtiRecipeEncoder, this.tracer,
+      this.fixedNames);
+}

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

@@ -2071,23 +2071,6 @@ class NamingScope {
   }
 }
 
-/// Fixed names usage by the namer.
-class FixedNames {
-  const FixedNames();
-
-  String get getterPrefix => r'get$';
-  String get setterPrefix => r'set$';
-  String get callPrefix => 'call';
-  String get callCatchAllName => r'call*';
-  String get callNameField => r'$callName';
-  String get defaultValuesField => r'$defaultValues';
-  String get deferredAction => r'$deferredAction';
-  String get operatorIsPrefix => r'$is';
-  String get operatorSignature => r'$signature';
-  String get requiredParameterField => r'$requiredArgCount';
-  String get rtiName => r'$ti';
-}
-
 /// Minified version of the fixed names usage by the namer.
 // TODO(johnniwinther): This should implement [FixedNames] and minify all fixed
 // names.
@@ -2130,6 +2113,7 @@ abstract class ModularNamer implements interfaces.ModularNamer {
   /// Returns a variable use for accessing interceptors.
   ///
   /// This is one of the [reservedGlobalObjectNames]
+  @override
   jsAst.Expression readGlobalObjectForInterceptors() {
     return DeferredHolderExpression.forInterceptors();
   }
@@ -2172,6 +2156,7 @@ abstract class ModularNamer implements interfaces.ModularNamer {
 
   /// Returns the name for the instance field that holds runtime type arguments
   /// on generic classes.
+  @override
   jsAst.Name get rtiFieldJsName;
 
   /// Property name on which [member] can be accessed directly,
@@ -2194,12 +2179,15 @@ abstract class ModularNamer implements interfaces.ModularNamer {
   ///         this.super$A$foo(); // super.foo()
   ///     }
   ///
+  @override
   jsAst.Name aliasedSuperMemberPropertyName(MemberEntity member);
 
   /// Returns the JavaScript property name used to store an instance field.
+  @override
   jsAst.Name instanceFieldPropertyName(FieldEntity element);
 
   /// Annotated name for [method] encoding arity and named parameters.
+  @override
   jsAst.Name instanceMethodName(FunctionEntity method);
 
   /// Translates a [String] into the corresponding [Name] data structure as
@@ -2207,9 +2195,11 @@ abstract class ModularNamer implements interfaces.ModularNamer {
   ///
   /// If [name] is a setter or getter name, the corresponding [GetterName] or
   /// [SetterName] data structure is used.
+  @override
   jsAst.Name asName(String name);
 
   /// Annotated name for the member being invoked by [selector].
+  @override
   jsAst.Name invocationName(Selector selector);
 
   /// Property name used for a specialization of `getInterceptor`.
@@ -2217,6 +2207,7 @@ abstract class ModularNamer implements interfaces.ModularNamer {
   /// js_runtime contains a top-level `getInterceptor` method. The
   /// specializations have the same name, but with a suffix to avoid name
   /// collisions.
+  @override
   jsAst.Name nameForGetInterceptor(Set<ClassEntity> classes);
 
   /// Property name used for the one-shot interceptor method for the given
@@ -2275,12 +2266,14 @@ abstract class ModularNamer implements interfaces.ModularNamer {
   }
 
   /// Returns the label name for [label] used as a break target.
+  @override
   String breakLabelName(LabelDefinition label) {
     return '\$${label.labelName}\$${label.target.nestingLevel}';
   }
 
   /// Returns the label name for the implicit break label needed for the jump
   /// [target].
+  @override
   String implicitBreakLabelName(JumpTarget target) {
     return '\$${target.nestingLevel}';
   }
@@ -2289,12 +2282,14 @@ abstract class ModularNamer implements interfaces.ModularNamer {
   ///
   /// We sometimes handle continue targets differently from break targets,
   /// so we have special continue-only labels.
+  @override
   String continueLabelName(LabelDefinition label) {
     return 'c\$${label.labelName}\$${label.target.nestingLevel}';
   }
 
   /// Returns the label name for the implicit continue label needed for the jump
   /// [target].
+  @override
   String implicitContinueLabelName(JumpTarget target) {
     return 'c\$${target.nestingLevel}';
   }

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

@@ -4,12 +4,25 @@
 
 import '../common.dart';
 import '../elements/entities.dart';
+import '../elements/jumps.dart';
 import '../js/js.dart' as jsAst;
 import '../universe/selector.dart' show Selector;
 import 'package:js_shared/synced/embedded_names.dart' show JsGetName;
 
 abstract class ModularNamer {
+  jsAst.Name get rtiFieldJsName;
+  jsAst.Name aliasedSuperMemberPropertyName(MemberEntity member);
+  jsAst.Name asName(String name);
+  String breakLabelName(LabelDefinition label);
+  String continueLabelName(LabelDefinition label);
+  String implicitBreakLabelName(JumpTarget target);
+  String implicitContinueLabelName(JumpTarget target);
+  jsAst.Name invocationName(Selector selector);
+  jsAst.Name instanceFieldPropertyName(FieldEntity element);
+  jsAst.Name instanceMethodName(FunctionEntity method);
+  jsAst.Name nameForGetInterceptor(Set<ClassEntity> classes);
   jsAst.Name nameForOneShotInterceptor(
       Selector selector, Set<ClassEntity> classes);
   jsAst.Name getNameForJsGetName(Spannable spannable, JsGetName name);
+  jsAst.Expression readGlobalObjectForInterceptors();
 }

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

@@ -37,3 +37,20 @@ String suffixForGetInterceptor(CommonElements commonElements,
   names.sort();
   return names.join();
 }
+
+/// Fixed names usage by the namer.
+class FixedNames {
+  const FixedNames();
+
+  String get getterPrefix => r'get$';
+  String get setterPrefix => r'set$';
+  String get callPrefix => 'call';
+  String get callCatchAllName => r'call*';
+  String get callNameField => r'$callName';
+  String get defaultValuesField => r'$defaultValues';
+  String get deferredAction => r'$deferredAction';
+  String get operatorIsPrefix => r'$is';
+  String get operatorSignature => r'$signature';
+  String get requiredParameterField => r'$requiredArgCount';
+  String get rtiName => r'$ti';
+}

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

@@ -15,24 +15,20 @@ import '../js/js.dart' as jsAst;
 import '../js/js.dart' show js;
 import '../js_model/type_recipe.dart';
 import '../js_emitter/js_emitter.dart' show ModularEmitter;
-import '../universe/class_hierarchy.dart';
 import '../world.dart';
 import 'namer.dart';
 import 'native_data.dart';
 import 'runtime_types_codegen.dart' show RuntimeTypesSubstitutions;
 import 'runtime_types_new_interfaces.dart' as interfaces;
+import 'runtime_types_new_migrated.dart';
 
-class RecipeEncoding {
-  final jsAst.Literal recipe;
-  final Set<TypeVariableType> typeVariables;
-
-  const RecipeEncoding(this.recipe, this.typeVariables);
-}
+export 'runtime_types_new_migrated.dart';
 
 abstract class RecipeEncoder implements interfaces.RecipeEncoder {
   /// Returns a [RecipeEncoding] representing the given [recipe] to be
   /// evaluated against a type environment with shape [structure].
-  RecipeEncoding encodeRecipe(ModularEmitter emitter,
+  @override
+  RecipeEncoding encodeRecipe(covariant ModularEmitter emitter,
       TypeEnvironmentStructure environmentStructure, TypeRecipe recipe);
 
   @override
@@ -416,52 +412,6 @@ class _RecipeGenerator implements DartTypeVisitor<void, void> {
   }
 }
 
-bool mustCheckAllSubtypes(JClosedWorld world, ClassEntity cls) =>
-    world.isUsedAsMixin(cls) ||
-    world.extractTypeArgumentsInterfacesNewRti.contains(cls);
-
-int indexTypeVariable(
-    JClosedWorld world,
-    RuntimeTypesSubstitutions rtiSubstitutions,
-    FullTypeEnvironmentStructure environment,
-    TypeVariableType type,
-    {bool metadata = false}) {
-  int i = environment.bindings.indexOf(type);
-  if (i >= 0) {
-    // Indices are 1-based since '0' encodes using the entire type for the
-    // singleton structure.
-    return i + 1;
-  }
-
-  TypeVariableEntity element = type.element;
-  ClassEntity cls = element.typeDeclaration;
-
-  if (metadata) {
-    if (identical(environment.classType.element, cls)) {
-      // Indexed class type variables come after the bound function type
-      // variables.
-      return 1 + environment.bindings.length + element.index;
-    }
-  }
-
-  // TODO(sra): We might be in a context where the class type variable has an
-  // index, even though in the general case it is not at a specific index.
-
-  ClassHierarchy classHierarchy = world.classHierarchy;
-  var test = mustCheckAllSubtypes(world, cls)
-      ? classHierarchy.anyStrictSubtypeOf
-      : classHierarchy.anyStrictSubclassOf;
-  if (test(cls, (ClassEntity subclass) {
-    return !rtiSubstitutions.isTrivialSubstitution(subclass, cls);
-  })) {
-    return null;
-  }
-
-  // Indexed class type variables come after the bound function type
-  // variables.
-  return 1 + environment.bindings.length + element.index;
-}
-
 class _RulesetEntry {
   final Set<InterfaceType> _supertypes = {};
   final Map<TypeVariableType, DartType> _typeVariables = {};

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

@@ -1,7 +1,10 @@
 import '../js_emitter/code_emitter_task_interfaces.dart';
 import '../js_model/type_recipe.dart';
 import '../js/js.dart' as jsAst;
+import 'runtime_types_new_migrated.dart';
 
 abstract class RecipeEncoder {
   jsAst.Literal encodeGroundRecipe(ModularEmitter emitter, TypeRecipe recipe);
+  RecipeEncoding encodeRecipe(ModularEmitter emitter,
+      TypeEnvironmentStructure environmentStructure, TypeRecipe recipe);
 }

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

@@ -0,0 +1,68 @@
+// 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.
+
+library js_backend.runtime_types_new_migrated;
+
+import '../elements/entities.dart';
+import '../elements/types.dart';
+import '../js/js.dart' as jsAst;
+import '../js_model/type_recipe.dart';
+import '../universe/class_hierarchy.dart';
+import '../world.dart';
+import 'runtime_types_codegen.dart' show RuntimeTypesSubstitutions;
+
+class RecipeEncoding {
+  final jsAst.Literal recipe;
+  final Set<TypeVariableType> typeVariables;
+
+  const RecipeEncoding(this.recipe, this.typeVariables);
+}
+
+int? indexTypeVariable(
+    JClosedWorld world,
+    RuntimeTypesSubstitutions rtiSubstitutions,
+    FullTypeEnvironmentStructure environment,
+    TypeVariableType type,
+    {bool metadata = false}) {
+  int i = environment.bindings.indexOf(type);
+  if (i >= 0) {
+    // Indices are 1-based since '0' encodes using the entire type for the
+    // singleton structure.
+    return i + 1;
+  }
+
+  TypeVariableEntity element = type.element;
+  // TODO(48820): remove `!`. Added to increase coverage of null assertions
+  // while the compiler runs in unsound null safety.
+  ClassEntity cls = element.typeDeclaration! as ClassEntity;
+
+  if (metadata) {
+    if (identical(environment.classType!.element, cls)) {
+      // Indexed class type variables come after the bound function type
+      // variables.
+      return 1 + environment.bindings.length + element.index;
+    }
+  }
+
+  // TODO(sra): We might be in a context where the class type variable has an
+  // index, even though in the general case it is not at a specific index.
+
+  ClassHierarchy classHierarchy = world.classHierarchy;
+  var test = mustCheckAllSubtypes(world, cls)
+      ? classHierarchy.anyStrictSubtypeOf
+      : classHierarchy.anyStrictSubclassOf;
+  if (test(cls, (ClassEntity subclass) {
+    return !rtiSubstitutions.isTrivialSubstitution(subclass, cls);
+  })) {
+    return null;
+  }
+
+  // Indexed class type variables come after the bound function type
+  // variables.
+  return 1 + environment.bindings.length + element.index;
+}
+
+bool mustCheckAllSubtypes(JClosedWorld world, ClassEntity cls) =>
+    world.isUsedAsMixin(cls) ||
+    world.extractTypeArgumentsInterfacesNewRti.contains(cls);

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

@@ -14,7 +14,7 @@ import '../constants/values.dart';
 import '../deferred_load/output_unit.dart' show OutputUnit;
 import '../elements/entities.dart';
 import '../js/js.dart' as jsAst;
-import '../js_backend/backend.dart' show CodegenInputs;
+import '../js_backend/codegen_inputs.dart' show CodegenInputs;
 import '../js_backend/inferred_data.dart';
 import '../js_backend/namer.dart' show Namer;
 import '../js_backend/runtime_types.dart' show RuntimeTypesChecks;
@@ -161,25 +161,31 @@ class CodeEmitterTask extends CompilerTask
 /// the closed world computed by the codegen enqueuer.
 abstract class ModularEmitter implements interfaces.ModularEmitter {
   /// Returns the JS prototype of the given class [e].
+  @override
   jsAst.Expression prototypeAccess(ClassEntity e);
 
   /// Returns the JS function representing the given function.
   ///
   /// The function must be invoked and can not be used as closure.
+  @override
   jsAst.Expression staticFunctionAccess(FunctionEntity element);
 
+  @override
   jsAst.Expression staticFieldAccess(FieldEntity element);
 
   /// Returns the JS function that must be invoked to get the value of the
   /// lazily initialized static.
+  @override
   jsAst.Expression isolateLazyInitializerAccess(covariant FieldEntity element);
 
   /// Returns the closure expression of a static function.
+  @override
   jsAst.Expression staticClosureAccess(covariant FunctionEntity element);
 
   /// Returns the JS constructor of the given element.
   ///
   /// The returned expression must only be used in a JS `new` expression.
+  @override
   jsAst.Expression constructorAccess(ClassEntity e);
 
   /// Returns the JS name representing the type [e].
@@ -192,6 +198,7 @@ abstract class ModularEmitter implements interfaces.ModularEmitter {
   jsAst.Expression generateEmbeddedGlobalAccess(String global);
 
   /// Returns the JS code for accessing the given [constant].
+  @override
   jsAst.Expression constantReference(ConstantValue constant);
 
   /// Returns the JS code for accessing the global property [global].

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

@@ -2,4 +2,16 @@
 // 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.
 
-abstract class ModularEmitter {}
+import '../constants/values.dart';
+import '../elements/entities.dart';
+import '../js/js.dart' as jsAst;
+
+abstract class ModularEmitter {
+  jsAst.Expression constructorAccess(ClassEntity e);
+  jsAst.Expression constantReference(ConstantValue constant);
+  jsAst.Expression isolateLazyInitializerAccess(covariant FieldEntity element);
+  jsAst.Expression prototypeAccess(ClassEntity e);
+  jsAst.Expression staticClosureAccess(covariant FunctionEntity element);
+  jsAst.Expression staticFieldAccess(FieldEntity element);
+  jsAst.Expression staticFunctionAccess(FunctionEntity element);
+}

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

@@ -31,6 +31,7 @@ import '../inferrer_experimental/type_graph_inferrer.dart'
 import '../js/js_source_mapping.dart';
 import '../js_backend/backend.dart';
 import '../js_backend/backend_impact.dart';
+import '../js_backend/codegen_inputs.dart';
 import '../js_backend/codegen_listener.dart';
 import '../js_backend/custom_elements_analysis.dart';
 import '../js_backend/enqueuer.dart';
@@ -38,6 +39,7 @@ import '../js_backend/impact_transformer.dart';
 import '../js_backend/inferred_data.dart';
 import '../js_backend/interceptor_data.dart';
 import '../js_backend/namer.dart';
+import '../js_backend/namer_migrated.dart';
 import '../js_backend/runtime_types.dart';
 import '../js_backend/runtime_types_codegen.dart';
 import '../js_backend/runtime_types_new.dart'

pkg/compiler/lib/src/serialization/task.dart

@@ -19,7 +19,7 @@ import '../environment.dart';
 import '../inferrer/abstract_value_strategy.dart';
 import '../inferrer/types.dart';
 import '../ir/modular.dart';
-import '../js_backend/backend.dart';
+import '../js_backend/codegen_inputs.dart';
 import '../js_backend/inferred_data.dart';
 import '../js_model/js_world.dart';
 import '../js_model/element_map_impl.dart';

pkg/compiler/lib/src/ssa/codegen.dart

@@ -13,7 +13,7 @@ import '../common.dart';
 import '../common/elements.dart' show JCommonElements;
 import '../common/metrics.dart';
 import '../common/names.dart';
-import '../common/codegen.dart' show CodegenRegistry;
+import '../common/codegen_interfaces.dart' show CodegenRegistry;
 import '../common/tasks.dart' show Measurer, CompilerTask;
 import '../constants/constant_system.dart' as constant_system;
 import '../constants/values.dart';
@@ -24,21 +24,22 @@ import '../inferrer/abstract_value_domain.dart';
 import '../io/source_information.dart';
 import '../js/js.dart' as js;
 import '../js_backend/interceptor_data.dart';
-import '../js_backend/backend.dart' show CodegenInputs;
+import '../js_backend/codegen_inputs.dart' show CodegenInputs;
 import '../js_backend/checked_mode_helpers.dart';
 import '../js_backend/native_data.dart';
-import '../js_backend/namer.dart' show ModularNamer;
+import '../js_backend/namer_interfaces.dart' show ModularNamer;
 import '../js_backend/runtime_types_codegen.dart';
-import '../js_backend/runtime_types_new.dart'
-    show RecipeEncoder, RecipeEncoding, indexTypeVariable;
+import '../js_backend/runtime_types_new_interfaces.dart' show RecipeEncoder;
+import '../js_backend/runtime_types_new_migrated.dart'
+    show RecipeEncoding, indexTypeVariable;
 import '../js_backend/specialized_checks.dart' show IsTestSpecialization;
 import '../js_backend/type_reference.dart' show TypeReference;
-import '../js_emitter/code_emitter_task.dart' show ModularEmitter;
+import '../js_emitter/code_emitter_task_interfaces.dart' show ModularEmitter;
 import '../js_model/elements.dart' show JGeneratorBody;
 import '../js_model/type_recipe.dart';
 import '../native/behavior.dart';
 import '../options.dart';
-import '../tracer.dart';
+import '../tracer_interfaces.dart';
 import '../universe/call_structure.dart' show CallStructure;
 import '../universe/selector.dart' show Selector;
 import '../universe/use.dart' show ConstantUse, DynamicUse, StaticUse, TypeUse;

pkg/compiler/lib/src/ssa/optimize.dart

@@ -19,7 +19,7 @@ import '../inferrer/types.dart';
 import '../ir/util.dart';
 import '../js_backend/field_analysis.dart'
     show FieldAnalysisData, JFieldAnalysis;
-import '../js_backend/backend.dart' show CodegenInputs;
+import '../js_backend/codegen_inputs.dart' show CodegenInputs;
 import '../js_backend/native_data.dart' show NativeData;
 import '../js_model/type_recipe.dart'
     show

pkg/compiler/lib/src/ssa/ssa.dart

@@ -19,7 +19,8 @@ import '../inferrer/types.dart';
 import '../io/source_information.dart';
 import '../js/js.dart' as js;
 import '../js/rewrite_async.dart';
-import '../js_backend/backend.dart' show CodegenInputs, FunctionCompiler;
+import '../js_backend/backend.dart' show FunctionCompiler;
+import '../js_backend/codegen_inputs.dart' show CodegenInputs;
 import '../js_backend/namer.dart' show ModularNamer, ModularNamerImpl;
 import '../js_backend/type_reference.dart' show TypeReference;
 import '../js_emitter/code_emitter_task.dart' show ModularEmitter;

pkg/compiler/lib/src/tracer.dart

@@ -13,12 +13,13 @@ import 'options.dart' show CompilerOptions;
 import 'ssa/nodes.dart' as ssa show HGraph;
 import 'ssa/tracer.dart' show HTracer;
 import 'world.dart' show JClosedWorld;
+import 'tracer_interfaces.dart' as interfaces;
 
 String TRACE_FILTER_PATTERN_FOR_TEST;
 
 /// Dumps the intermediate representation after each phase in a format
 /// readable by IR Hydra.
-class Tracer extends TracerUtil {
+class Tracer extends TracerUtil implements interfaces.Tracer {
   final JClosedWorld closedWorld;
   bool traceActive = false;
   @override
@@ -50,6 +51,7 @@ class Tracer extends TracerUtil {
     });
   }
 
+  @override
   void traceGraph(String name, var irObject) {
     if (!traceActive) return;
     if (irObject is ssa.HGraph) {
@@ -57,11 +59,13 @@ class Tracer extends TracerUtil {
     }
   }
 
+  @override
   void traceJavaScriptText(String name, String Function() getText) {
     if (!traceActive) return;
     HTracer(output, closedWorld).traceJavaScriptText(name, getText());
   }
 
+  @override
   void close() {
     if (output != null) {
       output.close();

pkg/compiler/lib/src/tracer_interfaces.dart

@@ -0,0 +1,9 @@
+// Copyright (c) 2022, 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.
+
+abstract class Tracer {
+  void traceGraph(String name, var irObject);
+  void traceJavaScriptText(String name, String Function() getText);
+  void close();
+}