[dart2js] Delete ImpactStrategy.

This strategy is no longer necessary with the single frontend, and
inlining all the logic makes the code much easier to follow.

Change-Id: I73995aa6249b52a932dbfb2d459c2d6633a620d2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/232029
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Joshua Litt <joshualitt@google.com>

pkg/compiler/lib/src/compiler.dart

@@ -40,7 +40,7 @@ import 'inferrer/types.dart'
     show GlobalTypeInferenceResults, GlobalTypeInferenceTask;
 import 'io/source_information.dart' show SourceInformation;
 import 'ir/modular.dart';
-import 'js_backend/backend.dart' show CodegenInputs, JavaScriptImpactStrategy;
+import 'js_backend/backend.dart' show CodegenInputs;
 import 'js_backend/inferred_data.dart';
 import 'js_model/js_strategy.dart';
 import 'js_model/js_world.dart';
@@ -57,8 +57,7 @@ import 'ssa/nodes.dart' show HInstruction;
 import 'universe/selector.dart' show Selector;
 import 'universe/codegen_world_builder.dart';
 import 'universe/resolution_world_builder.dart';
-import 'universe/world_impact.dart'
-    show ImpactStrategy, WorldImpact, WorldImpactBuilderImpl;
+import 'universe/world_impact.dart' show WorldImpact, WorldImpactBuilderImpl;
 import 'world.dart' show JClosedWorld, KClosedWorld;
 
 typedef MakeReporterFunction = CompilerDiagnosticReporter Function(
@@ -74,8 +73,6 @@ abstract class Compiler {
   CompilerDiagnosticReporter _reporter;
   Map<Entity, WorldImpact> _impactCache;
 
-  ImpactStrategy impactStrategy = const ImpactStrategy();
-
   /// Options provided from command-line arguments.
   final CompilerOptions options;
 
@@ -434,10 +431,6 @@ abstract class Compiler {
     // this until after the resolution queue is processed.
     deferredLoadTask.beforeResolution(rootLibraryUri, libraries);
 
-    impactStrategy = JavaScriptImpactStrategy(dumpInfoTask,
-        supportDeferredLoad: deferredLoadTask.isProgramSplit,
-        supportDumpInfo: options.dumpInfo);
-
     phase = PHASE_RESOLVING;
     resolutionEnqueuer.applyImpact(mainImpact);
     if (options.showInternalProgress) reporter.log('Computing closed world');
@@ -466,8 +459,6 @@ abstract class Compiler {
     _userCodeLocations
         .addAll(result.moduleLibraries.map((module) => CodeLocation(module)));
     selfTask.measureSubtask('runModularAnalysis', () {
-      impactStrategy = JavaScriptImpactStrategy(dumpInfoTask,
-          supportDeferredLoad: true, supportDumpInfo: true);
       var included = result.moduleLibraries.toSet();
       var elementMap = (frontendStrategy as KernelFrontendStrategy).elementMap;
       var moduleData = computeModuleData(result.component, included, options,
@@ -607,8 +598,7 @@ abstract class Compiler {
             work.element,
             () => selfTask.measureSubtask("applyImpact", () {
                   enqueuer.applyImpact(
-                      selfTask.measureSubtask("work.run", () => work.run()),
-                      impactSource: work.element);
+                      selfTask.measureSubtask("work.run", () => work.run()));
                 }));
       });
     });
@@ -619,7 +609,6 @@ abstract class Compiler {
       {void onProgress(Enqueuer enqueuer)}) {
     selfTask.measureSubtask("processQueue", () {
       enqueuer.open(
-          impactStrategy,
           mainMethod,
           elementEnvironment.libraries
               .map((LibraryEntity library) => library.canonicalUri));

pkg/compiler/lib/src/deferred_load/deferred_load.dart

@@ -286,7 +286,6 @@ import '../constants/values.dart' show ConstantValue;
 import '../elements/types.dart';
 import '../elements/entities.dart';
 import '../kernel/element_map.dart';
-import '../universe/world_impact.dart' show ImpactUseCase;
 import '../util/util.dart' show makeUnique;
 import '../world.dart' show KClosedWorld;
 
@@ -325,8 +324,6 @@ class DeferredLoadTask extends CompilerTask {
   /// Will be `true` if the program contains deferred libraries.
   bool isProgramSplit = false;
 
-  static const ImpactUseCase IMPACT_USE = ImpactUseCase('Deferred load');
-
   /// A cache of the result of calling `computeImportDeferName` on the keys of
   /// this map.
   final Map<ImportEntity, String> importDeferName = {};

pkg/compiler/lib/src/deferred_load/entity_data_info.dart

@@ -5,7 +5,6 @@
 import 'package:kernel/ast.dart' as ir;
 import 'package:kernel/type_environment.dart' as ir;
 
-import 'deferred_load.dart';
 import 'entity_data.dart';
 
 import '../common.dart';
@@ -19,8 +18,7 @@ import '../ir/util.dart';
 import '../kernel/kelements.dart' show KLocalFunction;
 import '../kernel/element_map.dart';
 import '../universe/use.dart';
-import '../universe/world_impact.dart'
-    show ImpactStrategy, WorldImpact, WorldImpactVisitorImpl;
+import '../universe/world_impact.dart' show WorldImpact, WorldImpactVisitorImpl;
 import '../world.dart' show KClosedWorld;
 
 /// [EntityDataInfo] is meta data about [EntityData] for a given compilation
@@ -63,7 +61,6 @@ class EntityDataInfoBuilder {
       this.closedWorld, this.elementMap, this.compiler, this.registry);
 
   Map<Entity, WorldImpact> get impactCache => compiler.impactCache;
-  ImpactStrategy get impactStrategy => compiler.impactStrategy;
   KElementEnvironment get elementEnvironment =>
       compiler.frontendStrategy.elementEnvironment;
   CommonElements get commonElements => compiler.frontendStrategy.commonElements;
@@ -242,20 +239,16 @@ class EntityDataInfoBuilder {
   /// Extract any dependencies that are known from the impact of [element].
   void _addDependenciesFromImpact(MemberEntity element) {
     WorldImpact worldImpact = impactCache[element];
-    impactStrategy.visitImpact(
-        element,
-        worldImpact,
-        WorldImpactVisitorImpl(
-            visitStaticUse: (MemberEntity member, StaticUse staticUse) {
-          _addFromStaticUse(element, staticUse);
-        }, visitTypeUse: (MemberEntity member, TypeUse typeUse) {
-          _addFromTypeUse(element, typeUse);
-        }, visitDynamicUse: (MemberEntity member, DynamicUse dynamicUse) {
-          // TODO(johnniwinther): Use rti need data to skip unneeded type
-          // arguments.
-          addTypeListDependencies(dynamicUse.typeArguments);
-        }),
-        DeferredLoadTask.IMPACT_USE);
+    worldImpact.apply(WorldImpactVisitorImpl(
+        visitStaticUse: (MemberEntity member, StaticUse staticUse) {
+      _addFromStaticUse(element, staticUse);
+    }, visitTypeUse: (MemberEntity member, TypeUse typeUse) {
+      _addFromTypeUse(element, typeUse);
+    }, visitDynamicUse: (MemberEntity member, DynamicUse dynamicUse) {
+      // TODO(johnniwinther): Use rti need data to skip unneeded type
+      // arguments.
+      addTypeListDependencies(dynamicUse.typeArguments);
+    }));
   }
 }
 

pkg/compiler/lib/src/dump_info.dart

@@ -27,8 +27,7 @@ import 'inferrer/types.dart'
 import 'js/js.dart' as jsAst;
 import 'js_backend/field_analysis.dart';
 import 'universe/codegen_world_builder.dart';
-import 'universe/world_impact.dart'
-    show ImpactUseCase, WorldImpact, WorldImpactVisitorImpl;
+import 'universe/world_impact.dart' show WorldImpact, WorldImpactVisitorImpl;
 import 'util/sink_adapter.dart';
 import 'world.dart' show JClosedWorld;
 
@@ -427,7 +426,6 @@ abstract class InfoReporter {
 }
 
 class DumpInfoTask extends CompilerTask implements InfoReporter {
-  static const ImpactUseCase IMPACT_USE = ImpactUseCase('Dump info');
   final Compiler compiler;
   final bool useBinaryFormat;
 
@@ -493,20 +491,17 @@ class DumpInfoTask extends CompilerTask implements InfoReporter {
     if (impact == null) return const <Selection>[];
 
     var selections = <Selection>[];
-    compiler.impactStrategy.visitImpact(
-        entity,
-        impact,
-        WorldImpactVisitorImpl(visitDynamicUse: (member, dynamicUse) {
-          AbstractValue mask = dynamicUse.receiverConstraint;
-          selections.addAll(closedWorld
-              // TODO(het): Handle `call` on `Closure` through
-              // `world.includesClosureCall`.
-              .locateMembers(dynamicUse.selector, mask)
-              .map((MemberEntity e) => Selection(e, mask)));
-        }, visitStaticUse: (member, staticUse) {
-          selections.add(Selection(staticUse.element, null));
-        }),
-        IMPACT_USE);
+    impact.apply(WorldImpactVisitorImpl(visitDynamicUse: (member, dynamicUse) {
+      AbstractValue mask = dynamicUse.receiverConstraint;
+      selections.addAll(closedWorld
+          // TODO(het): Handle `call` on `Closure` through
+          // `world.includesClosureCall`.
+          .locateMembers(dynamicUse.selector, mask)
+          .map((MemberEntity e) => Selection(e, mask)));
+    }, visitStaticUse: (member, staticUse) {
+      selections.add(Selection(staticUse.element, null));
+    }));
+    unregisterImpact(entity);
     return selections;
   }
 

pkg/compiler/lib/src/enqueue.dart

@@ -30,8 +30,7 @@ import 'universe/use.dart'
         StaticUseKind,
         TypeUse,
         TypeUseKind;
-import 'universe/world_impact.dart'
-    show ImpactStrategy, ImpactUseCase, WorldImpact, WorldImpactVisitor;
+import 'universe/world_impact.dart' show WorldImpact, WorldImpactVisitor;
 import 'util/enumset.dart';
 import 'util/util.dart' show Setlet;
 import 'world.dart' show JClosedWorld;
@@ -144,6 +143,7 @@ abstract class Enqueuer {
   static bool skipEnqueuerCheckForTesting = false;
 
   WorldBuilder get worldBuilder;
+  WorldImpactVisitor get impactVisitor;
 
   /// Returns [:true:] if this enqueuer is the resolution enqueuer.
   bool get isResolutionQueue;
@@ -152,14 +152,14 @@ abstract class Enqueuer {
 
   bool get queueIsEmpty;
 
-  ImpactUseCase get impactUse;
-
   void forEach(void f(WorkItem work));
 
-  /// Apply the [worldImpact] to this enqueuer. If the [impactSource] is
-  /// provided the impact strategy will remove it from the element impact cache,
-  /// if it is no longer needed.
-  void applyImpact(WorldImpact worldImpact, {var impactSource});
+  /// Apply the [worldImpact] to this enqueuer.
+  void applyImpact(WorldImpact worldImpact) {
+    if (worldImpact.isEmpty) return;
+    worldImpact.apply(impactVisitor);
+  }
+
   bool checkNoEnqueuedInvokedInstanceMethods(
       ElementEnvironment elementEnvironment);
 
@@ -179,21 +179,11 @@ abstract class Enqueuer {
   void processConstantUse(ConstantUse constantUse);
   EnqueuerListener get listener;
 
-  // TODO(johnniwinther): Initialize [_impactStrategy] to `null`.
-  ImpactStrategy _impactStrategy = const ImpactStrategy();
-
-  ImpactStrategy get impactStrategy => _impactStrategy;
-
-  void open(ImpactStrategy impactStrategy, FunctionEntity mainMethod,
-      Iterable<Uri> libraries) {
-    _impactStrategy = impactStrategy;
+  void open(FunctionEntity mainMethod, Iterable<Uri> libraries) {
     listener.onQueueOpen(this, mainMethod, libraries);
   }
 
   void close() {
-    // TODO(johnniwinther): Set [_impactStrategy] to `null` and [queueIsClosed]
-    // to `true` here.
-    _impactStrategy = const ImpactStrategy();
     listener.onQueueClosed();
   }
 
@@ -216,8 +206,6 @@ abstract class Enqueuer {
 
 /// [Enqueuer] which is specific to resolution.
 class ResolutionEnqueuer extends Enqueuer {
-  static const ImpactUseCase IMPACT_USE = ImpactUseCase('ResolutionEnqueuer');
-
   @override
   final CompilerTask task;
   final String name;
@@ -234,7 +222,8 @@ class ResolutionEnqueuer extends Enqueuer {
   @override
   bool queueIsClosed = false;
 
-  WorldImpactVisitor _impactVisitor;
+  @override
+  WorldImpactVisitor impactVisitor;
 
   final Queue<WorkItem> _queue = Queue<WorkItem>();
 
@@ -245,7 +234,7 @@ class ResolutionEnqueuer extends Enqueuer {
   ResolutionEnqueuer(this.task, this._reporter, this.listener,
       this._worldBuilder, this._workItemBuilder, this._annotationsData,
       [this.name = 'resolution enqueuer']) {
-    _impactVisitor = EnqueuerImpactVisitor(this);
+    impactVisitor = EnqueuerImpactVisitor(this);
   }
 
   @override
@@ -264,13 +253,6 @@ class ResolutionEnqueuer extends Enqueuer {
   @override
   Iterable<ClassEntity> get processedClasses => _worldBuilder.processedClasses;
 
-  @override
-  void applyImpact(WorldImpact worldImpact, {var impactSource}) {
-    if (worldImpact.isEmpty) return;
-    impactStrategy.visitImpact(
-        impactSource, worldImpact, _impactVisitor, impactUse);
-  }
-
   void _registerInstantiatedType(InterfaceType type,
       {ConstructorEntity constructor,
       bool nativeUsage = false,
@@ -310,8 +292,7 @@ class ResolutionEnqueuer extends Enqueuer {
       _registerClosurizedMember(member);
     }
     if (useSet.contains(MemberUse.CLOSURIZE_STATIC)) {
-      applyImpact(listener.registerGetOfStaticFunction(),
-          impactSource: 'get of static function');
+      applyImpact(listener.registerGetOfStaticFunction());
     }
   }
 
@@ -323,12 +304,10 @@ class ResolutionEnqueuer extends Enqueuer {
       // We only tell the backend once that [cls] was instantiated, so
       // any additional dependencies must be treated as global
       // dependencies.
-      applyImpact(listener.registerInstantiatedClass(cls),
-          impactSource: 'instantiated class');
+      applyImpact(listener.registerInstantiatedClass(cls));
     }
     if (useSet.contains(ClassUse.IMPLEMENTED)) {
-      applyImpact(listener.registerImplementedClass(cls),
-          impactSource: 'implemented class');
+      applyImpact(listener.registerImplementedClass(cls));
     }
   }
 
@@ -343,8 +322,7 @@ class ResolutionEnqueuer extends Enqueuer {
   void processConstantUse(ConstantUse constantUse) {
     task.measureSubtask('resolution.constantUse', () {
       if (_worldBuilder.registerConstantUse(constantUse)) {
-        applyImpact(listener.registerUsedConstant(constantUse.value),
-            impactSource: 'constant use');
+        applyImpact(listener.registerUsedConstant(constantUse.value));
         _recentConstants = true;
       }
     });
@@ -427,8 +405,7 @@ class ResolutionEnqueuer extends Enqueuer {
 
   void _registerClosurizedMember(MemberEntity element) {
     assert(element.isInstanceMember);
-    applyImpact(listener.registerClosurizedMember(element),
-        impactSource: 'closurized member');
+    applyImpact(listener.registerClosurizedMember(element));
     _worldBuilder.registerClosurizedMember(element);
   }
 
@@ -474,9 +451,6 @@ class ResolutionEnqueuer extends Enqueuer {
   Iterable<MemberEntity> get processedEntities =>
       _worldBuilder.processedMembers;
 
-  @override
-  ImpactUseCase get impactUse => IMPACT_USE;
-
   @override
   bool get isResolutionQueue => true;
 
@@ -506,8 +480,7 @@ class ResolutionEnqueuer extends Enqueuer {
           entity, "Resolution work list is closed. Trying to add $entity.");
     }
 
-    applyImpact(listener.registerUsedElement(entity),
-        impactSource: 'used element');
+    applyImpact(listener.registerUsedElement(entity));
     _worldBuilder.registerUsedElement(entity);
     _queue.add(workItem);
   }

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

@@ -6,15 +6,10 @@ library js_backend.backend;
 
 import '../common.dart';
 import '../common/codegen.dart';
-import '../deferred_load/deferred_load.dart' show DeferredLoadTask;
-import '../dump_info.dart' show DumpInfoTask;
 import '../elements/entities.dart';
-import '../enqueue.dart' show ResolutionEnqueuer;
 import '../inferrer/types.dart';
 import '../js_model/elements.dart';
 import '../tracer.dart';
-import '../universe/world_impact.dart'
-    show ImpactStrategy, ImpactUseCase, WorldImpact, WorldImpactVisitor;
 import 'annotations.dart';
 import 'checked_mode_helpers.dart';
 import 'namer.dart';
@@ -261,36 +256,6 @@ class FunctionInlineCache {
   }
 }
 
-class JavaScriptImpactStrategy extends ImpactStrategy {
-  final DumpInfoTask dumpInfoTask;
-  final bool supportDeferredLoad;
-  final bool supportDumpInfo;
-
-  JavaScriptImpactStrategy(this.dumpInfoTask,
-      {this.supportDeferredLoad, this.supportDumpInfo});
-
-  @override
-  void visitImpact(var impactSource, WorldImpact impact,
-      WorldImpactVisitor visitor, ImpactUseCase impactUse) {
-    // TODO(johnniwinther): Compute the application strategy once for each use.
-    if (impactUse == ResolutionEnqueuer.IMPACT_USE) {
-      if (supportDeferredLoad) {
-        impact.apply(visitor);
-      } else {
-        impact.apply(visitor);
-      }
-    } else if (impactUse == DeferredLoadTask.IMPACT_USE) {
-      impact.apply(visitor);
-      // Impacts are uncached globally in [onImpactUsed].
-    } else if (impactUse == DumpInfoTask.IMPACT_USE) {
-      impact.apply(visitor);
-      dumpInfoTask.unregisterImpact(impactSource);
-    } else {
-      impact.apply(visitor);
-    }
-  }
-}
-
 /// Interface for resources only used during code generation.
 abstract class CodegenInputs {
   CheckedModeHelpers get checkedModeHelpers;

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

@@ -24,8 +24,7 @@ import '../universe/use.dart'
         StaticUseKind,
         TypeUse,
         TypeUseKind;
-import '../universe/world_impact.dart'
-    show ImpactUseCase, WorldImpact, WorldImpactVisitor;
+import '../universe/world_impact.dart' show WorldImpactVisitor;
 import '../util/enumset.dart';
 import '../util/util.dart' show Setlet;
 
@@ -45,7 +44,8 @@ class CodegenEnqueuer extends Enqueuer {
   final EnqueuerListener listener;
   final AnnotationsData _annotationsData;
 
-  WorldImpactVisitor _impactVisitor;
+  @override
+  WorldImpactVisitor impactVisitor;
 
   final Queue<WorkItem> _queue = Queue<WorkItem>();
 
@@ -56,12 +56,10 @@ class CodegenEnqueuer extends Enqueuer {
   // applying additional impacts before re-emptying the queue.
   void Function() onEmptyForTesting;
 
-  static const ImpactUseCase IMPACT_USE = ImpactUseCase('CodegenEnqueuer');
-
   CodegenEnqueuer(this.task, this._worldBuilder, this._workItemBuilder,
       this.listener, this._annotationsData)
       : this.name = 'codegen enqueuer' {
-    _impactVisitor = EnqueuerImpactVisitor(this);
+    impactVisitor = EnqueuerImpactVisitor(this);
   }
 
   @override
@@ -97,13 +95,6 @@ class CodegenEnqueuer extends Enqueuer {
     _queue.add(workItem);
   }
 
-  @override
-  void applyImpact(WorldImpact worldImpact, {var impactSource}) {
-    if (worldImpact.isEmpty) return;
-    impactStrategy.visitImpact(
-        impactSource, worldImpact, _impactVisitor, impactUse);
-  }
-
   void _registerInstantiatedType(InterfaceType type,
       {bool nativeUsage = false}) {
     task.measureSubtask('codegen.typeUse', () {
@@ -307,9 +298,6 @@ class CodegenEnqueuer extends Enqueuer {
   @override
   String toString() => 'Enqueuer($name)';
 
-  @override
-  ImpactUseCase get impactUse => IMPACT_USE;
-
   @override
   Iterable<MemberEntity> get processedEntities => _processedEntities;
 

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

@@ -137,18 +137,15 @@ class ResolutionEnqueuerListener extends EnqueuerListener {
   void onQueueOpen(
       Enqueuer enqueuer, FunctionEntity mainMethod, Iterable<Uri> libraries) {
     if (_deferredLoadTask.isProgramSplit) {
-      enqueuer.applyImpact(_computeDeferredLoadingImpact(),
-          impactSource: 'deferred load');
+      enqueuer.applyImpact(_computeDeferredLoadingImpact());
     }
-    enqueuer.applyImpact(_nativeEnqueuer.processNativeClasses(libraries),
-        impactSource: 'native classes');
+    enqueuer.applyImpact(_nativeEnqueuer.processNativeClasses(libraries));
     if (mainMethod != null) {
-      enqueuer.applyImpact(_computeMainImpact(mainMethod),
-          impactSource: 'main impact');
+      enqueuer.applyImpact(_computeMainImpact(mainMethod));
     }
     // Elements required by enqueueHelpers are global dependencies
     // that are not pulled in by a particular element.
-    enqueuer.applyImpact(computeHelpersImpact(), impactSource: 'helpers');
+    enqueuer.applyImpact(computeHelpersImpact());
   }
 
   @override
@@ -158,8 +155,7 @@ class ResolutionEnqueuerListener extends EnqueuerListener {
     //
     // Return early if any elements are added to avoid counting the elements as
     // due to mirrors.
-    enqueuer.applyImpact(_customElementsAnalysis.flush(),
-        impactSource: _customElementsAnalysis);
+    enqueuer.applyImpact(_customElementsAnalysis.flush());
 
     for (ClassEntity cls in recentClasses) {
       MemberEntity element = _elementEnvironment.lookupLocalClassMember(

pkg/compiler/lib/src/universe/world_impact.dart

@@ -303,28 +303,6 @@ class TransformedWorldImpact implements WorldImpact, WorldImpactBuilder {
   }
 }
 
-/// Constant used to denote a specific use of a [WorldImpact].
-class ImpactUseCase {
-  final String name;
-
-  const ImpactUseCase(this.name);
-
-  @override
-  String toString() => 'ImpactUseCase($name)';
-}
-
-/// Strategy used for processing [WorldImpact] object in various use cases.
-class ImpactStrategy {
-  const ImpactStrategy();
-
-  /// Applies [impact] to [visitor] for the [impactUseCase] of [impactSource].
-  void visitImpact(var impactSource, WorldImpact impact,
-      WorldImpactVisitor visitor, ImpactUseCase impactUseCase) {
-    // Apply unconditionally.
-    impact.apply(visitor);
-  }
-}
-
 /// Visitor used to process the uses of a [WorldImpact].
 abstract class WorldImpactVisitor {
   void visitStaticUse(MemberEntity member, StaticUse staticUse);