Revert "Added for-loop variable tracking and regular closures/initializers captured variable tracki…

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

-// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2016, 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:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../common/tasks.dart';
 import '../elements/entities.dart';
 import '../kernel/element_map.dart';
 import '../world.dart';
-import 'elements.dart';
-import 'closure_visitors.dart';
 import 'locals.dart';
 
+class KernelClosureDataBuilder extends ir.Visitor {
+  final KernelToLocalsMap _localsMap;
+  final KernelClosureRepresentationInfo info;
+
+  bool _inTry = false;
+
+  KernelClosureDataBuilder(this._localsMap, ThisLocal thisLocal)
+      : info = new KernelClosureRepresentationInfo(thisLocal);
+
+  @override
+  defaultNode(ir.Node node) {
+    node.visitChildren(this);
+  }
+
+  @override
+  visitTryCatch(ir.TryCatch node) {
+    bool oldInTry = _inTry;
+    _inTry = true;
+    node.visitChildren(this);
+    _inTry = oldInTry;
+  }
+
+  @override
+  visitTryFinally(ir.TryFinally node) {
+    bool oldInTry = _inTry;
+    _inTry = true;
+    node.visitChildren(this);
+    _inTry = oldInTry;
+  }
+
+  @override
+  visitVariableGet(ir.VariableGet node) {
+    if (_inTry) {
+      info.registerUsedInTryOrSync(_localsMap.getLocal(node.variable));
+    }
+  }
+
+  @override
+  visitVariableSet(ir.VariableSet node) {
+    if (_inTry) {
+      info.registerUsedInTryOrSync(_localsMap.getLocal(node.variable));
+    }
+    node.visitChildren(this);
+  }
+}
+
 /// Closure conversion code using our new Entity model. Closure conversion is
 /// necessary because the semantics of closures are slightly different in Dart
 /// than JavaScript. Closure conversion is separated out into two phases:
 /// generation of a new (temporary) representation to store where variables need
 /// to be hoisted/captured up at another level to re-write the closure, and then
 /// the code generation phase where we generate elements and/or instructions to
 /// represent this new code path.
 ///
 /// For a general explanation of how closure conversion works at a high level,
 /// check out:
 /// http://siek.blogspot.com/2012/07/essence-of-closure-conversion.html or
 /// http://matt.might.net/articles/closure-conversion/.
-// TODO(efortuna): Change inheritance hierarchy so that the
-// ClosureConversionTask doesn't inherit from ClosureTask because it's just a
-// glorified timer.
 class KernelClosureConversionTask extends ClosureConversionTask<ir.Node> {
   final KernelToElementMapForBuilding _elementMap;
   final GlobalLocalsMap _globalLocalsMap;
-  Map<ir.Node, ClosureScope> _closureScopeMap = <ir.Node, ClosureScope>{};
-
-  Map<Entity, ClosureRepresentationInfo> _closureRepresentationMap =
+  Map<Entity, ClosureRepresentationInfo> _infoMap =
       <Entity, ClosureRepresentationInfo>{};
 
-  /// Should only be used at the very beginning to ensure we are looking at the
-  /// right kind of elements.
-  // TODO(efortuna): Remove this map once we have one kernel backend strategy.
-  final JsToFrontendMap _kToJElementMap;
-
-  KernelClosureConversionTask(Measurer measurer, this._elementMap,
-      this._kToJElementMap, this._globalLocalsMap)
+  KernelClosureConversionTask(
+      Measurer measurer, this._elementMap, this._globalLocalsMap)
       : super(measurer);
 
   /// The combined steps of generating our intermediate representation of
   /// closures that need to be rewritten and generating the element model.
   /// Ultimately these two steps will be split apart with the second step
   /// happening later in compilation just before codegen. These steps are
   /// combined here currently to provide a consistent interface to the rest of
   /// the compiler until we are ready to separate these phases.
   @override
   void convertClosures(Iterable<MemberEntity> processedEntities,
       ClosedWorldRefiner closedWorldRefiner) {
-    var closuresToGenerate = <ir.Node, ScopeInfo>{};
-    processedEntities.forEach((MemberEntity kEntity) {
-      MemberEntity entity = kEntity;
-      if (_kToJElementMap != null) {
-        entity = _kToJElementMap.toBackendMember(kEntity);
-      }
-      if (entity.isAbstract) return;
-      if (entity.isField && !entity.isInstanceMember) {
-        ir.Field field = _elementMap.getMemberNode(entity);
-        // Skip top-level/static fields without an initializer.
-        if (field.initializer == null) return;
-      }
-      _buildClosureModel(entity, closuresToGenerate, closedWorldRefiner);
-    });
-
-    for (ir.Node node in closuresToGenerate.keys) {
-      _produceSyntheticElements(
-          node, closuresToGenerate[node], closedWorldRefiner);
-    }
+    // TODO(efortuna): implement.
   }
 
-  /// Inspect members and mark if those members capture any state that needs to
-  /// be marked as free variables.
-  void _buildClosureModel(
-      MemberEntity entity,
-      Map<ir.Node, ScopeInfo> closuresToGenerate,
-      ClosedWorldRefiner closedWorldRefiner) {
-    ir.Node node = _elementMap.getMemberNode(entity);
-    if (_closureScopeMap.keys.contains(node)) return;
-    ClosureScopeBuilder translator = new ClosureScopeBuilder(_closureScopeMap,
-        closuresToGenerate, _globalLocalsMap.getLocalsMap(entity), _elementMap);
-    if (entity.isField) {
-      if (node is ir.Field && node.initializer != null) {
-        translator.translateLazyInitializer(node);
-      }
-    } else {
-      assert(node is ir.Procedure || node is ir.Constructor);
-      translator.translateConstructorOrProcedure(node);
-    }
-  }
-
-  /// Given what variables are captured at each point, construct closure classes
-  /// with fields containing the captured variables to replicate the Dart
-  /// closure semantics in JS.
-  void _produceSyntheticElements(
-      ir.Node node, ScopeInfo info, ClosedWorldRefiner closedWorldRefiner) {
-    Entity entity;
-    KernelClosureClass closureClass =
-        new KernelClosureClass.fromScopeInfo(info);
-    if (node is ir.FunctionNode) {
-      // We want the original declaration where that function is used to point
-      // to the correct closure class.
-      // TODO(efortuna): entity equivalent of element.declaration?
-      node = (node as ir.FunctionNode).parent;
-      _closureRepresentationMap[closureClass.callMethod] = closureClass;
-    }
-
-    if (node is ir.Member) {
-      entity = _elementMap.getMember(node);
-    } else {
-      entity = _elementMap.getLocalFunction(node);
-    }
-    assert(entity != null);
-
-    _closureRepresentationMap[entity] = closureClass;
+  /// TODO(johnniwinther,efortuna): Implement this.
+  @override
+  ClosureScope getClosureScope(ir.Node node) {
+    return const ClosureScope();
   }
 
   @override
   ScopeInfo getScopeInfo(Entity entity) {
+    // TODO(efortuna): Specialize this function from the one below.
     return getClosureRepresentationInfo(entity);
   }
 
+  /// TODO(johnniwinther,efortuna): Implement this.
   @override
-  // TODO(efortuna): Eventually closureScopeMap[node] should always be non-null,
-  // and we should just test that with an assert.
-  ClosureScope getClosureScope(ir.Node node) =>
-      _closureScopeMap[node] ?? const ClosureScope();
+  LoopClosureScope getLoopClosureScope(ir.Node loopNode) {
+    return const LoopClosureScope();
+  }
 
   @override
-  // TODO(efortuna): Eventually closureScopeMap[node] should always be non-null,
-  // and we should just test that with an assert.
-  LoopClosureScope getLoopClosureScope(ir.Node loopNode) =>
-      _closureScopeMap[node] ?? const LoopClosureScope();
+  ClosureRepresentationInfo getClosureRepresentationInfo(Entity entity) {
+    return _infoMap.putIfAbsent(entity, () {
+      if (entity is MemberEntity) {
+        ir.Member node = _elementMap.getMemberNode(entity);
+        ThisLocal thisLocal;
+        if (entity.isInstanceMember) {
+          thisLocal = new ThisLocal(entity);
+        }
+        KernelClosureDataBuilder builder = new KernelClosureDataBuilder(
+            _globalLocalsMap.getLocalsMap(entity), thisLocal);
+        node.accept(builder);
+        return builder.info;
+      }
 
-  @override
-  // TODO(efortuna): Eventually closureRepresentationMap[node] should always be
-  // non-null, and we should just test that with an assert.
-  ClosureRepresentationInfo getClosureRepresentationInfo(Entity entity) =>
-      _closureRepresentationMap[entity] ?? const ClosureRepresentationInfo();
+      /// TODO(johnniwinther,efortuna): Implement this.
+      return const ClosureRepresentationInfo();
+    });
+  }
 }
 
-class KernelScopeInfo extends ScopeInfo {
-  final Set<Local> localsUsedInTryOrSync;
-  final Local thisLocal;
-  final Set<Local> boxedVariables = new Set<Local>();
+// TODO(johnniwinther): Add unittest for the computed
+// [ClosureRepresentationInfo].
+class KernelClosureRepresentationInfo extends ClosureRepresentationInfo {
+  final ThisLocal thisLocal;
+  final Set<Local> _localsUsedInTryOrSync = new Set<Local>();
 
-  /// The set of variables that were defined in another scope, but are used in
-  /// this scope.
-  Set<ir.VariableDeclaration> freeVariables = new Set<ir.VariableDeclaration>();
+  KernelClosureRepresentationInfo(this.thisLocal);
 
-  KernelScopeInfo(this.thisLocal) : localsUsedInTryOrSync = new Set<Local>();
-
-  KernelScopeInfo.from(this.thisLocal, KernelScopeInfo info)
-      : localsUsedInTryOrSync = info.variablesUsedInTryOrSync,
-        boxedVariables = info.boxedVariables;
-
-  KernelScopeInfo.withBoxedVariables(this.boxedVariables, this.thisLocal);
-
-  void forEachBoxedVariable(f(Local local, FieldEntity field)) {
-    boxedVariables.forEach((Local l) {
-      // TODO(efortuna): add FieldEntities as created.
-      f(l, null);
-    });
+  void registerUsedInTryOrSync(Local local) {
+    _localsUsedInTryOrSync.add(local);
   }
 
-  bool localIsUsedInTryOrSync(Local variable) =>
-      localsUsedInTryOrSync.contains(variable);
+  bool variableIsUsedInTryOrSync(Local variable) =>
+      _localsUsedInTryOrSync.contains(variable);
 
   String toString() {
     StringBuffer sb = new StringBuffer();
     sb.write('this=$thisLocal,');
-    sb.write('localsUsedInTryOrSync={${localsUsedInTryOrSync.join(', ')}}');
+    sb.write('localsUsedInTryOrSync={${_localsUsedInTryOrSync.join(', ')}}');
     return sb.toString();
   }
-
-  bool isBoxed(Local variable) => boxedVariables.contains(variable);
 }
-
-class KernelClosureScope extends KernelScopeInfo implements ClosureScope {
-  final Local context;
-
-  KernelClosureScope(Set<Local> boxedVariables, this.context, Local thisLocal)
-      : super.withBoxedVariables(boxedVariables, thisLocal);
-
-  bool get requiresContextBox => boxedVariables.isNotEmpty;
-}
-
-class KernelLoopClosureScope extends KernelClosureScope
-    implements LoopClosureScope {
-  final List<Local> boxedLoopVariables;
-
-  KernelLoopClosureScope(Set<Local> boxedVariables, this.boxedLoopVariables,
-      Local context, Local thisLocal)
-      : super(boxedVariables, context, thisLocal);
-
-  bool get hasBoxedLoopVariables => boxedLoopVariables.isNotEmpty;
-}
-
-// TODO(johnniwinther): Add unittest for the computed [ClosureClass].
-class KernelClosureClass extends KernelScopeInfo
-    implements ClosureRepresentationInfo {
-  KernelClosureClass.fromScopeInfo(ScopeInfo info)
-      : super.from(info.thisLocal, info);
-
-  // TODO(efortuna): Implement.
-  Local get closureEntity => null;
-
-  // TODO(efortuna): Implement.
-  ClassEntity get closureClassEntity => null;
-
-  // TODO(efortuna): Implement.
-  FunctionEntity get callMethod => null;
-
-  // TODO(efortuna): Implement.
-  List<Local> get createdFieldEntities => const <Local>[];
-
-  // TODO(efortuna): Implement.
-  FieldEntity get thisFieldEntity => null;
-
-  // TODO(efortuna): Implement.
-  void forEachCapturedVariable(f(Local from, FieldEntity to)) {}
-
-  // TODO(efortuna): Implement.
-  @override
-  void forEachBoxedVariable(f(Local local, FieldEntity field)) {}
-
-  // TODO(efortuna): Implement.
-  void forEachFreeVariable(f(Local variable, FieldEntity field)) {}
-
-  // TODO(efortuna): Implement.
-  bool isVariableBoxed(Local variable) => false;
-
-  // TODO(efortuna): Implement.
-  // Why is this closure not actually a closure? Well, to properly call
-  // ourselves a closure, we need to register the new closure class with the
-  // ClosedWorldRefiner, which currently only takes elements. The change to
-  // that (and the subsequent adjustment here) will follow soon.
-  bool get isClosure => false;
-}