Add typeinfo for sets and their elements and start tracing them in the inferrer.

Change-Id: Ib9a4e46b77a15ab17396d519166969a221b63da4
Reviewed-on: https://dart-review.googlesource.com/c/92168
Reviewed-by: Sigmund Cherem <sigmund@google.com>

pkg/compiler/lib/src/inferrer/node_tracer.dart

@@ -81,17 +81,23 @@ abstract class TracerVisitor implements TypeInformationVisitor {
 
   TracerVisitor(this.tracedType, this.inferrer);
 
-  // Work list that gets populated with [TypeInformation] that could
-  // contain the container.
+  /// Work list that gets populated with [TypeInformation] that could
+  /// contain the container.
   final List<TypeInformation> workList = <TypeInformation>[];
 
-  // Work list of lists to analyze after analyzing the users of a
-  // [TypeInformation]. We know the [tracedType] has been stored in these
-  // lists and we must check how it escapes from these lists.
+  /// Work list of lists to analyze after analyzing the users of a
+  /// [TypeInformation]. We know the [tracedType] has been stored in these
+  /// lists and we must check how it escapes from these lists.
   final List<ListTypeInformation> listsToAnalyze = <ListTypeInformation>[];
-  // Work list of maps to analyze after analyzing the users of a
-  // [TypeInformation]. We know the [tracedType] has been stored in these
-  // maps and we must check how it escapes from these maps.
+
+  /// Work list of sets to analyze after analyzing the users of a
+  /// [TypeInformation]. We know the [tracedType] has been stored in these sets
+  /// and we must check how it escapes from these sets.
+  final List<SetTypeInformation> setsToAnalyze = <SetTypeInformation>[];
+
+  /// Work list of maps to analyze after analyzing the users of a
+  /// [TypeInformation]. We know the [tracedType] has been stored in these
+  /// maps and we must check how it escapes from these maps.
   final List<MapTypeInformation> mapsToAnalyze = <MapTypeInformation>[];
 
   final Setlet<TypeInformation> flowsInto = new Setlet<TypeInformation>();
@@ -175,6 +181,10 @@ abstract class TracerVisitor implements TypeInformationVisitor {
     addNewEscapeInformation(info);
   }
 
+  void visitElementInSetTypeInformation(ElementInSetTypeInformation info) {
+    addNewEscapeInformation(info);
+  }
+
   void visitKeyInMapTypeInformation(KeyInMapTypeInformation info) {
     // We do not track the use of keys from a map, so we have to bail.
     bailout('Used as key in Map');
@@ -188,6 +198,10 @@ abstract class TracerVisitor implements TypeInformationVisitor {
     listsToAnalyze.add(info);
   }
 
+  void visitSetTypeInformation(SetTypeInformation info) {
+    setsToAnalyze.add(info);
+  }
+
   void visitMapTypeInformation(MapTypeInformation info) {
     mapsToAnalyze.add(info);
   }

pkg/compiler/lib/src/inferrer/type_graph_dump.dart

@@ -335,6 +335,10 @@ class _GraphGenerator extends TypeInformationVisitor {
     addNode(info, 'ElementInContainer');
   }
 
+  void visitElementInSetTypeInformation(ElementInSetTypeInformation info) {
+    addNode(info, 'ElementInSet');
+  }
+
   void visitKeyInMapTypeInformation(KeyInMapTypeInformation info) {
     addNode(info, 'KeyInMap');
   }
@@ -347,6 +351,10 @@ class _GraphGenerator extends TypeInformationVisitor {
     addNode(info, 'List');
   }
 
+  void visitSetTypeInformation(SetTypeInformation info) {
+    addNode(info, 'Set');
+  }
+
   void visitMapTypeInformation(MapTypeInformation info) {
     addNode(info, 'Map');
   }

pkg/compiler/lib/src/inferrer/type_graph_nodes.dart

@@ -1580,6 +1580,65 @@ class ElementInContainerTypeInformation extends InferredTypeInformation {
   }
 }
 
+/// A [SetTypeInformation] is a [TypeInformation] created for sets.
+class SetTypeInformation extends TypeInformation with TracedTypeInformation {
+  final ElementInSetTypeInformation elementType;
+
+  final AbstractValue originalType;
+
+  SetTypeInformation(
+      MemberTypeInformation context, this.originalType, this.elementType)
+      : super(originalType, context) {
+    elementType.addUser(this);
+  }
+
+  String toString() => 'Set type $type';
+
+  accept(TypeInformationVisitor visitor) {
+    return visitor.visitSetTypeInformation(this);
+  }
+
+  AbstractValue computeType(InferrerEngine inferrer) {
+    AbstractValueDomain abstractValueDomain = inferrer.abstractValueDomain;
+    AbstractValue mask = type;
+    if (!abstractValueDomain.isSet(type) ||
+        abstractValueDomain.getSetElementType(type) != elementType.type) {
+      return abstractValueDomain.createSetValue(
+          abstractValueDomain.getGeneralization(originalType),
+          abstractValueDomain.getAllocationNode(originalType),
+          abstractValueDomain.getAllocationElement(originalType),
+          elementType.type);
+    }
+    return mask;
+  }
+
+  AbstractValue safeType(InferrerEngine inferrer) => originalType;
+
+  bool hasStableType(InferrerEngine inferrer) {
+    return elementType.isStable && super.hasStableType(inferrer);
+  }
+
+  void cleanup() {
+    super.cleanup();
+    elementType.cleanup();
+    _flowsInto = null;
+  }
+}
+
+/// An [ElementInSetTypeInformation] holds the common type of the elements in a
+/// [SetTypeInformation].
+class ElementInSetTypeInformation extends InferredTypeInformation {
+  ElementInSetTypeInformation(AbstractValueDomain abstractValueDomain,
+      MemberTypeInformation context, elementType)
+      : super(abstractValueDomain, context, elementType);
+
+  String toString() => 'Element in set $type';
+
+  accept(TypeInformationVisitor visitor) {
+    return visitor.visitElementInSetTypeInformation(this);
+  }
+}
+
 /// A [MapTypeInformation] is a [TypeInformation] created
 /// for maps.
 class MapTypeInformation extends TypeInformation with TracedTypeInformation {
@@ -1920,9 +1979,11 @@ abstract class TypeInformationVisitor<T> {
   T visitPhiElementTypeInformation(PhiElementTypeInformation info);
   T visitElementInContainerTypeInformation(
       ElementInContainerTypeInformation info);
+  T visitElementInSetTypeInformation(ElementInSetTypeInformation info);
   T visitKeyInMapTypeInformation(KeyInMapTypeInformation info);
   T visitValueInMapTypeInformation(ValueInMapTypeInformation info);
   T visitListTypeInformation(ListTypeInformation info);
+  T visitSetTypeInformation(SetTypeInformation info);
   T visitMapTypeInformation(MapTypeInformation info);
   T visitConcreteTypeInformation(ConcreteTypeInformation info);
   T visitStringLiteralTypeInformation(StringLiteralTypeInformation info);