Revert "Move dart2js from sdk/lib/_internal/compiler to pkg/compiler"

pkg/compiler/lib/src/types/union_type_mask.dart

Index: pkg/compiler/lib/src/types/union_type_mask.dart
diff --git a/pkg/compiler/lib/src/types/union_type_mask.dart b/pkg/compiler/lib/src/types/union_type_mask.dart
deleted file mode 100644
index 0ad1cc67095241a9ac67ed5849be6389ab535ed6..0000000000000000000000000000000000000000
--- a/pkg/compiler/lib/src/types/union_type_mask.dart
+++ /dev/null
@@ -1,347 +0,0 @@
-// Copyright (c) 2013, 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.
-
-part of types;
-
-class UnionTypeMask implements TypeMask {
-  final Iterable<FlatTypeMask> disjointMasks;
-
-  static const int MAX_UNION_LENGTH = 4;
-
-  UnionTypeMask._internal(this.disjointMasks) {
-    assert(disjointMasks.length > 1);
-    assert(disjointMasks.every((TypeMask mask) => !mask.isUnion));
-  }
-
-  static TypeMask unionOf(Iterable<TypeMask> masks, ClassWorld classWorld) {
-    assert(masks.every((mask) => TypeMask.assertIsNormalized(mask, classWorld)));
-    List<FlatTypeMask> disjoint = <FlatTypeMask>[];
-    unionOfHelper(masks, disjoint, classWorld);
-    if (disjoint.isEmpty) return new TypeMask.nonNullEmpty();
-    if (disjoint.length > MAX_UNION_LENGTH) {
-      return flatten(disjoint, classWorld);
-    }
-    if (disjoint.length == 1) return disjoint[0];
-    UnionTypeMask union = new UnionTypeMask._internal(disjoint);
-    assert(TypeMask.assertIsNormalized(union, classWorld));
-    return union;
-  }
-
-  static void unionOfHelper(Iterable<TypeMask> masks,
-                            List<FlatTypeMask> disjoint,
-                            ClassWorld classWorld) {
-    // TODO(johnniwinther): Impose an order on the mask to ensure subclass masks
-    // are preferred to subtype masks.
-    for (TypeMask mask in masks) {
-      mask = TypeMask.nonForwardingMask(mask);
-      if (mask.isUnion) {
-        UnionTypeMask union = mask;
-        unionOfHelper(union.disjointMasks, disjoint, classWorld);
-      } else if (mask.isEmpty && !mask.isNullable) {
-        continue;
-      } else {
-        FlatTypeMask flatMask = mask;
-        int inListIndex = -1;
-        bool covered = false;
-
-        // Iterate over [disjoint] to find out if one of the mask
-        // already covers [mask].
-        for (int i = 0; i < disjoint.length; i++) {
-          FlatTypeMask current = disjoint[i];
-          if (current == null) continue;
-          TypeMask newMask = flatMask.union(current, classWorld);
-          // If we have found a disjoint union, continue iterating.
-          if (newMask.isUnion) continue;
-          covered = true;
-          // We found a mask that is either equal to [mask] or is a
-          // supertype of [mask].
-          if (current == newMask) break;
-
-          // [mask] is a supertype of [current], replace the [disjoint]
-          // list with [newMask] instead of [current]. Note that
-          // [newMask] may contain different information than [mask],
-          // like nullability.
-          disjoint[i] = newMask;
-          flatMask = newMask;
-
-          if (inListIndex != -1) {
-            // If the mask was already covered, we remove the previous
-            // place where it was inserted. This new mask subsumes the
-            // previously covered one.
-            disjoint.removeAt(inListIndex);
-            i--;
-          }
-          // Record where the mask was inserted.
-          inListIndex = i;
-        }
-        // If none of the masks in [disjoint] covers [mask], we just
-        // add [mask] to the list.
-        if (!covered) disjoint.add(flatMask);
-      }
-    }
-  }
-
-  static TypeMask flatten(List<FlatTypeMask> masks, ClassWorld classWorld) {
-    assert(masks.length > 1);
-    // If either type mask is a subtype type mask, we cannot use a
-    // subclass type mask to represent their union.
-    bool useSubclass = masks.every((e) => !e.isSubtype);
-    bool isNullable = masks.any((e) => e.isNullable);
-
-    Iterable<ClassElement> candidates =
-        classWorld.commonSupertypesOf(masks.map((mask) => mask.base));
-
-    // Compute the best candidate and its kind.
-    ClassElement bestElement;
-    int bestKind;
-    int bestSize;
-    for (ClassElement candidate in candidates) {
-      Iterable<ClassElement> subclasses = useSubclass
-          ? classWorld.subclassesOf(candidate)
-          : const <ClassElement>[];
-      int size;
-      int kind;
-      if (masks.every((t) => subclasses.contains(t.base))) {
-        // If both [this] and [other] are subclasses of the supertype,
-        // then we prefer to construct a subclass type mask because it
-        // will always be at least as small as the corresponding
-        // subtype type mask.
-        kind = FlatTypeMask.SUBCLASS;
-        size = subclasses.length;
-        assert(size <= classWorld.subtypesOf(candidate).length);
-      } else {
-        kind = FlatTypeMask.SUBTYPE;
-        size = classWorld.subtypesOf(candidate).length;
-      }
-      // Update the best candidate if the new one is better.
-      if (bestElement == null || size < bestSize) {
-        bestElement = candidate;
-        bestSize = size;
-        bestKind = kind;
-      }
-    }
-    return new TypeMask(bestElement, bestKind, isNullable, classWorld);
-  }
-
-  TypeMask union(var other, ClassWorld classWorld) {
-    other = TypeMask.nonForwardingMask(other);
-    if (!other.isUnion && disjointMasks.contains(other)) return this;
-
-    List<FlatTypeMask> newList =
-        new List<FlatTypeMask>.from(disjointMasks);
-    if (!other.isUnion) {
-      newList.add(other);
-    } else {
-      assert(other is UnionTypeMask);
-      newList.addAll(other.disjointMasks);
-    }
-    return new TypeMask.unionOf(newList, classWorld);
-  }
-
-  TypeMask intersection(var other, ClassWorld classWorld) {
-    other = TypeMask.nonForwardingMask(other);
-    if (!other.isUnion && disjointMasks.contains(other)) return other;
-
-    List<TypeMask> intersections = <TypeMask>[];
-    for (TypeMask current in disjointMasks) {
-      if (other.isUnion) {
-        for (FlatTypeMask flatOther in other.disjointMasks) {
-          intersections.add(current.intersection(flatOther, classWorld));
-        }
-      } else {
-        intersections.add(current.intersection(other, classWorld));
-      }
-    }
-    return new TypeMask.unionOf(intersections, classWorld);
-  }
-
-  TypeMask nullable() {
-    if (isNullable) return this;
-    List<FlatTypeMask> newList = new List<FlatTypeMask>.from(disjointMasks);
-    newList[0] = newList[0].nullable();
-    return new UnionTypeMask._internal(newList);
-  }
-
-  TypeMask nonNullable() {
-    if (!isNullable) return this;
-    Iterable<FlatTypeMask> newIterable =
-        disjointMasks.map((e) => e.nonNullable());
-    return new UnionTypeMask._internal(newIterable);
-  }
-
-  bool get isEmpty => false;
-  bool get isNullable => disjointMasks.any((e) => e.isNullable);
-  bool get isExact => false;
-  bool get isUnion => true;
-  bool get isContainer => false;
-  bool get isMap => false;
-  bool get isDictionary => false;
-  bool get isForwarding => false;
-  bool get isValue => false;
-
-  /**
-   * Checks whether [other] is contained in this union.
-   *
-   * Invariants:
-   * - [other] may not be a [UnionTypeMask] itself
-   * - the cheap test matching against individual members of [disjointMasks]
-   *   must have failed.
-   */
-  bool slowContainsCheck(TypeMask other, ClassWorld classWorld) {
-    // Unions should never make it here.
-    assert(!other.isUnion);
-    // Ensure the cheap test fails.
-    assert(!disjointMasks.any((mask) => mask.containsMask(other, classWorld)));
-    // If we cover object, we should never get here.
-    assert(!contains(classWorld.objectClass, classWorld));
-    // Likewise, nullness should be covered.
-    assert(isNullable || !other.isNullable);
-    // The fast test is precise for exact types.
-    if (other.isExact) return false;
-    // We cannot contain object.
-    if (other.contains(classWorld.objectClass, classWorld)) return false;
-    FlatTypeMask flat = TypeMask.nonForwardingMask(other);
-    // Check we cover the base class.
-    if (!contains(flat.base, classWorld)) return false;
-    // Check for other members.
-    Iterable<ClassElement> members;
-    if (flat.isSubclass) {
-      members = classWorld.subclassesOf(flat.base);
-    } else {
-      assert(flat.isSubtype);
-      members = classWorld.subtypesOf(flat.base);
-    }
-    return members.every((ClassElement cls) => this.contains(cls, classWorld));
-  }
-
-  bool isInMask(TypeMask other, ClassWorld classWorld) {
-    other = TypeMask.nonForwardingMask(other);
-    if (isNullable && !other.isNullable) return false;
-    if (other.isUnion) {
-      UnionTypeMask union = other;
-      bool containedInAnyOf(FlatTypeMask mask, Iterable<FlatTypeMask> masks) {
-        // null is not canonicalized for the union but stored only on some
-        // masks in [disjointMask]. It has been checked in the surrounding
-        // context, so we can safely ignore it here.
-        FlatTypeMask maskDisregardNull = mask.nonNullable();
-        return masks.any((FlatTypeMask other) {
-          return other.containsMask(maskDisregardNull, classWorld);
-        });
-      }
-      return disjointMasks.every((FlatTypeMask disjointMask) {
-        bool contained = containedInAnyOf(disjointMask, union.disjointMasks);
-        assert(contained || !union.slowContainsCheck(disjointMask, classWorld));
-        return contained;
-      });
-    }
-    return disjointMasks.every((mask) => mask.isInMask(other, classWorld));
-  }
-
-  bool containsMask(TypeMask other, ClassWorld classWorld) {
-    other = TypeMask.nonForwardingMask(other);
-    if (other.isNullable && !isNullable) return false;
-    if (other.isUnion) return other.isInMask(this, classWorld);
-    other = other.nonNullable(); // nullable is not canonicalized, so drop it.
-    bool contained =
-        disjointMasks.any((mask) => mask.containsMask(other, classWorld));
-    assert(contained || !slowContainsCheck(other, classWorld));
-    return contained;
-  }
-
-  bool containsOnlyInt(ClassWorld classWorld) {
-    return disjointMasks.every((mask) => mask.containsOnlyInt(classWorld));
-  }
-
-  bool containsOnlyDouble(ClassWorld classWorld) {
-    return disjointMasks.every((mask) => mask.containsOnlyDouble(classWorld));
-  }
-
-  bool containsOnlyNum(ClassWorld classWorld) {
-    return disjointMasks.every((mask) {
-      return mask.containsOnlyNum(classWorld);
-    });
-  }
-
-  bool containsOnlyBool(ClassWorld classWorld) {
-    return disjointMasks.every((mask) => mask.containsOnlyBool(classWorld));
-  }
-
-  bool containsOnlyString(ClassWorld classWorld) {
-    return disjointMasks.every((mask) => mask.containsOnlyString(classWorld));
-  }
-
-  bool containsOnly(ClassElement element) {
-    return disjointMasks.every((mask) => mask.containsOnly(element));
-  }
-
-  bool satisfies(ClassElement cls, ClassWorld classWorld) {
-    return disjointMasks.every((mask) => mask.satisfies(cls, classWorld));
-  }
-
-  bool contains(ClassElement type, ClassWorld classWorld) {
-    return disjointMasks.any((e) => e.contains(type, classWorld));
-  }
-
-  bool containsAll(ClassWorld classWorld) {
-    return disjointMasks.any((mask) => mask.containsAll(classWorld));
-  }
-
-  ClassElement singleClass(ClassWorld classWorld) => null;
-
-  bool needsNoSuchMethodHandling(Selector selector, ClassWorld classWorld) {
-    return disjointMasks.any(
-        (e) => e.needsNoSuchMethodHandling(selector, classWorld));
-  }
-
-  bool canHit(Element element, Selector selector, ClassWorld classWorld) {
-    return disjointMasks.any((e) => e.canHit(element, selector, classWorld));
-  }
-
-  Element locateSingleElement(Selector selector, Compiler compiler) {
-    Element candidate;
-    for (FlatTypeMask mask in disjointMasks) {
-      Element current = mask.locateSingleElement(selector, compiler);
-      if (current == null) {
-        return null;
-      } else if (candidate == null) {
-        candidate = current;
-      } else if (candidate != current) {
-        return null;
-      }
-    }
-    return candidate;
-  }
-
-  String toString() {
-    String masksString = (disjointMasks.map((TypeMask mask) => mask.toString())
-        .toList()..sort()).join(", ");
-    return 'Union of [$masksString]';
-  }
-
-  bool operator==(other) {
-    if (identical(this, other)) return true;
-
-    bool containsAll() {
-      return other.disjointMasks.every((e) {
-        var map = disjointMasks.map((e) => e.nonNullable());
-        return map.contains(e.nonNullable());
-      });
-    }
-
-    return other is UnionTypeMask
-        && other.isNullable == isNullable
-        && other.disjointMasks.length == disjointMasks.length
-        && containsAll();
-  }
-
-  int get hashCode {
-    int hashCode = isNullable ? 86 : 43;
-    // The order of the masks in [disjointMasks] must not affect the
-    // hashCode.
-    for (var mask in disjointMasks) {
-      hashCode = (hashCode ^ mask.nonNullable().hashCode) & 0x3fffffff;
-    }
-    return hashCode;
-  }
-}