dart2js: Move TypeTestRegistry into its own file.

pkg/compiler/lib/src/js_emitter/type_test_registry.dart

Index: pkg/compiler/lib/src/js_emitter/type_test_registry.dart
diff --git a/pkg/compiler/lib/src/js_emitter/type_test_registry.dart b/pkg/compiler/lib/src/js_emitter/type_test_registry.dart
new file mode 100644
index 0000000000000000000000000000000000000000..ead7fd3905faa5d950bad3a230dfbe9bf3b68180
--- /dev/null
+++ b/pkg/compiler/lib/src/js_emitter/type_test_registry.dart
@@ -0,0 +1,163 @@
+// Copyright (c) 2014, 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 dart2js.js_emitter;
+
+class TypeTestRegistry {
+  /**
+   * Raw ClassElement symbols occuring in is-checks and type assertions.  If the
+   * program contains parameterized checks `x is Set<int>` and
+   * `x is Set<String>` then the ClassElement `Set` will occur once in
+   * [checkedClasses].
+   */
+  Set<ClassElement> checkedClasses;
+
+  /**
+   * The set of function types that checked, both explicity through tests of
+   * typedefs and implicitly through type annotations in checked mode.
+   */
+  Set<FunctionType> checkedFunctionTypes;
+
+  /// Initially contains all classes that need RTI. After
+  /// [computeNeededClasses]
+  /// this set only contains classes that are only used for RTI.
+  final Set<ClassElement> rtiNeededClasses = new Set<ClassElement>();
+
+  Iterable<ClassElement> cachedClassesUsingTypeVariableTests;
+
+  Iterable<ClassElement> get classesUsingTypeVariableTests {
+    if (cachedClassesUsingTypeVariableTests == null) {
+      cachedClassesUsingTypeVariableTests = compiler.codegenWorld.isChecks
+          .where((DartType t) => t is TypeVariableType)
+          .map((TypeVariableType v) => v.element.enclosingClass)
+          .toList();
+    }
+    return cachedClassesUsingTypeVariableTests;
+  }
+
+  final Compiler compiler;
+
+  TypeTestRegistry(this.compiler);
+
+  JavaScriptBackend get backend => compiler.backend;
+
+  /**
+   * Returns the classes with constructors used as a 'holder' in
+   * [emitRuntimeTypeSupport].
+   * TODO(9556): Some cases will go away when the class objects are created as
+   * complete.  Not all classes will go away while constructors are referenced
+   * from type substitutions.
+   */
+  Set<ClassElement> classesModifiedByEmitRuntimeTypeSupport() {
+    TypeChecks typeChecks = backend.rti.requiredChecks;
+    Set<ClassElement> result = new Set<ClassElement>();
+    for (ClassElement cls in typeChecks) {
+      for (TypeCheck check in typeChecks[cls]) {
+        result.add(cls);
+        break;
+      }
+    }
+    return result;
+  }
+
+  Set<ClassElement> computeRtiNeededClasses() {
+    void addClassWithSuperclasses(ClassElement cls) {
+      rtiNeededClasses.add(cls);
+      for (ClassElement superclass = cls.superclass;
+          superclass != null;
+          superclass = superclass.superclass) {
+        rtiNeededClasses.add(superclass);
+      }
+    }
+
+    void addClassesWithSuperclasses(Iterable<ClassElement> classes) {
+      for (ClassElement cls in classes) {
+        addClassWithSuperclasses(cls);
+      }
+    }
+
+    // 1.  Add classes that are referenced by type arguments or substitutions in
+    //     argument checks.
+    // TODO(karlklose): merge this case with 2 when unifying argument and
+    // object checks.
+    RuntimeTypes rti = backend.rti;
+    rti.getRequiredArgumentClasses(backend)
+       .forEach(addClassWithSuperclasses);
+
+    // 2.  Add classes that are referenced by substitutions in object checks and
+    //     their superclasses.
+    TypeChecks requiredChecks =
+        rti.computeChecks(rtiNeededClasses, checkedClasses);
+    Set<ClassElement> classesUsedInSubstitutions =
+        rti.getClassesUsedInSubstitutions(backend, requiredChecks);
+    addClassesWithSuperclasses(classesUsedInSubstitutions);
+
+    // 3.  Add classes that contain checked generic function types. These are
+    //     needed to store the signature encoding.
+    for (FunctionType type in checkedFunctionTypes) {
+      ClassElement contextClass = Types.getClassContext(type);
+      if (contextClass != null) {
+        rtiNeededClasses.add(contextClass);
+      }
+    }
+
+    bool canTearOff(Element function) {
+      if (!function.isFunction ||
+          function.isConstructor ||
+          function.isAccessor) {
+        return false;
+      } else if (function.isInstanceMember) {
+        if (!function.enclosingClass.isClosure) {
+          return compiler.codegenWorld.hasInvokedGetter(
+              function, compiler.world);
+        }
+      }
+      return false;
+    }
+
+    bool canBeReflectedAsFunction(Element element) {
+      return element.kind == ElementKind.FUNCTION ||
+          element.kind == ElementKind.GETTER ||
+          element.kind == ElementKind.SETTER ||
+          element.kind == ElementKind.GENERATIVE_CONSTRUCTOR;
+    }
+
+    bool canBeReified(Element element) {
+      return (canTearOff(element) || backend.isAccessibleByReflection(element));
+    }
+
+    // Find all types referenced from the types of elements that can be
+    // reflected on 'as functions'.
+    backend.generatedCode.keys.where((element) {
+      return canBeReflectedAsFunction(element) && canBeReified(element);
+    }).forEach((FunctionElement function) {
+      DartType type = function.computeType(compiler);
+      for (ClassElement cls in backend.rti.getReferencedClasses(type)) {
+        while (cls != null) {
+          rtiNeededClasses.add(cls);
+          cls = cls.superclass;
+        }
+      }
+    });
+
+    return rtiNeededClasses;
+  }
+
+  void computeRequiredTypeChecks() {
+    assert(checkedClasses == null && checkedFunctionTypes == null);
+
+    backend.rti.addImplicitChecks(compiler.codegenWorld,
+                                  classesUsingTypeVariableTests);
+
+    checkedClasses = new Set<ClassElement>();
+    checkedFunctionTypes = new Set<FunctionType>();
+    compiler.codegenWorld.isChecks.forEach((DartType t) {
+      if (t is InterfaceType) {
+        checkedClasses.add(t.element);
+      } else if (t is FunctionType) {
+        checkedFunctionTypes.add(t);
+      }
+    });
+  }
+}