Implement a list tracer phase, that tries to find element types in individual lists.

tests/compiler/dart2js/list_tracer_test.dart

+// 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.
+
+import 'package:expect/expect.dart';
+import
+    '../../../sdk/lib/_internal/compiler/implementation/types/types.dart'
+    show ContainerTypeMask, TypeMask;
+
+import 'compiler_helper.dart';
+import 'parser_helper.dart';
+
+
+String generateTest(String listAllocation) {
+  return """
+int anInt = 42;
+double aDouble = 42.5;
+
+class A {
+  final field;
+  var nonFinalField;
+
+  A(this.field);
+
+  A.bar(list) {
+    nonFinalField = list;
+  }
+
+  receiveIt(list) {
+    list[0] = aDouble;
+  }
+
+  returnIt() {
+    return listReturnedFromSelector;
+  }
+
+  useField() {
+    field[0] = aDouble;
+  }
+
+  set callSetter(list) {
+    list[0] = aDouble;
+  }
+
+  operator[](index) {
+    index[0] = aDouble;
+  }
+
+  operator[]=(index, value) {
+    index[0] = anInt;
+    if (value == listEscapingTwiceInIndexSet) {
+      value[0] = aDouble;
+    }
+  }
+}
+
+class B extends A {
+  B(list) : super.bar(list);
+
+  set nonFinalField(value) {
+    value[0] = aDouble;
+  }
+}
+
+var listInField = $listAllocation;
+var listPassedToClosure = $listAllocation;
+var listReturnedFromClosure = $listAllocation;
+var listPassedToMethod = $listAllocation;
+var listReturnedFromMethod = $listAllocation;
+var listUsedWithCascade = $listAllocation;
+var listUsedInClosure = $listAllocation;
+var listPassedToSelector = $listAllocation;
+var listReturnedFromSelector = $listAllocation;
+var listUsedWithAddAndInsert = $listAllocation;
+var listUsedWithNonOkSelector = $listAllocation;
+var listUsedWithConstraint = $listAllocation;
+var listEscapingFromSetter = $listAllocation;
+var listUsedInLocal = $listAllocation;
+var listUnset = $listAllocation;
+var listOnlySetWithConstraint = $listAllocation;
+var listEscapingInSetterValue = $listAllocation;
+var listEscapingInIndex = $listAllocation;
+var listEscapingInIndexSet = $listAllocation;
+var listEscapingTwiceInIndexSet = $listAllocation;
+var listPassedAsOptionalParameter = $listAllocation;
+var listPassedAsNamedParameter = $listAllocation;
+var listSetInNonFinalField = $listAllocation;
+
+foo(list) {
+  list[0] = aDouble;
+}
+
+bar() {
+  return listReturnedFromMethod;
+}
+
+takeOptional([list]) {
+  list[0] = aDouble;
+}
+
+takeNamed({list}) {
+  list[0] = aDouble;
+}
+
+main() {
+  listReturnedFromMethod[0] = anInt;
+  bar()[0] = aDouble;
+
+  listPassedToMethod[0] = anInt;
+  foo(listPassedToMethod);
+
+  listPassedToClosure[0] = anInt;
+  ((a) => a[0] = aDouble)(listPassedToClosure);
+
+  listReturnedFromClosure[0] = anInt;
+  (() => listReturnedFromClosure)[0] = aDouble;
+
+  listInField[0] = anInt;
+  new A(listInField).useField();
+
+  listUsedWithCascade[0] = anInt;
+  listUsedWithCascade..[0] = aDouble;
+
+  listUsedInClosure[0] = anInt;
+  (() => listUsedInClosure[0] = aDouble)();
+
+  listPassedToSelector[0] = anInt;
+  new A(null).receiveIt(listPassedToSelector);
+
+  listReturnedFromSelector[0] = anInt;
+  new A(null).returnIt()[0] = aDouble;
+
+  listUsedWithAddAndInsert.add(anInt);
+  listUsedWithAddAndInsert.insert(0, aDouble);
+
+  listUsedWithNonOkSelector[0] = anInt;
+  listUsedWithNonOkSelector.addAll(listPassedToClosure);
+
+  listUsedWithConstraint[0] = anInt;
+  listUsedWithConstraint[0]++;
+  listUsedWithConstraint[0] += anInt;
+
+  listEscapingFromSetter[0] = anInt;
+  foo(new A(null).field = listEscapingFromSetter);
+
+  listUsedInLocal[0] = anInt;
+  var a = listUsedInLocal;
+  listUsedInLocal[1] = aDouble;
+
+  // At least use [listUnused] in a local to pretend it's used.
+  var b = listUnset;
+
+  listOnlySetWithConstraint[0]++;
+
+  listEscapingInSetterValue[0] = anInt;
+  new A().callSetter = listEscapingInSetterValue;
+
+  listEscapingInIndex[0] = anInt;
+  new A()[listEscapingInIndex];
+
+  new A()[listEscapingInIndexSet] = 42;
+
+  new A()[listEscapingTwiceInIndexSet] = listEscapingTwiceInIndexSet;
+
+  listPassedAsOptionalParameter[0] = anInt;
+  takeOptional(listPassedAsOptionalParameter);
+
+  listPassedAsNamedParameter[0] = anInt;
+  takeNamed(list: listPassedAsNamedParameter);
+
+  listSetInNonFinalField[0] = anInt;
+  new B(listSetInNonFinalField);
+}
+""";
+}
+
+void main() {
+  doTest('[]'); // Test literal list.
+  doTest('new List()'); // Test growable list.
+  doTest('new List(1)'); // Test fixed list.
+}
+
+void doTest(String allocation) {
+  Uri uri = new Uri(scheme: 'source');
+  var compiler = compilerFor(generateTest(allocation), uri);
+  compiler.runCompiler(uri);
+  var typesInferrer = compiler.typesTask.typesInferrer;
+
+  checkType(String name, type) {
+    var element = findElement(compiler, name);
+    ContainerTypeMask mask = typesInferrer.internal.typeOf[element];
+    Expect.equals(type, mask.elementType.simplify(compiler), name);
+  }
+
+  checkType('listInField', typesInferrer.numType.nullable());
+  checkType('listPassedToMethod', typesInferrer.numType.nullable());
+  checkType('listReturnedFromMethod', typesInferrer.numType.nullable());
+  checkType('listUsedWithCascade', typesInferrer.numType.nullable());
+  checkType('listUsedInClosure', typesInferrer.numType.nullable());
+  checkType('listPassedToSelector', typesInferrer.numType.nullable());
+  checkType('listReturnedFromSelector', typesInferrer.numType.nullable());
+  checkType('listUsedWithAddAndInsert', typesInferrer.numType.nullable());
+  checkType('listUsedWithConstraint', typesInferrer.numType.nullable());
+  checkType('listEscapingFromSetter', typesInferrer.numType.nullable());
+  checkType('listUsedInLocal', typesInferrer.numType.nullable());
+  checkType('listEscapingInSetterValue', typesInferrer.numType.nullable());
+  checkType('listEscapingInIndex', typesInferrer.numType.nullable());
+  checkType('listEscapingInIndexSet', typesInferrer.intType.nullable());
+  checkType('listEscapingTwiceInIndexSet', typesInferrer.numType.nullable());
+  checkType('listSetInNonFinalField', typesInferrer.numType.nullable());
+
+  checkType('listPassedToClosure', typesInferrer.dynamicType);
+  checkType('listReturnedFromClosure', typesInferrer.dynamicType);
+  checkType('listUsedWithNonOkSelector', typesInferrer.dynamicType);
+  checkType('listPassedAsOptionalParameter', typesInferrer.dynamicType);
+  checkType('listPassedAsNamedParameter', typesInferrer.dynamicType);
+
+  checkType('listUnset', new TypeMask.empty());
+  checkType('listOnlySetWithConstraint', new TypeMask.empty());
+}