Refactor enqueuers

pkg/compiler/lib/src/js_backend/mirrors_analysis.dart

+// 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.
+
+library dart2js.mirrors_handler;
+
+import '../common/resolution.dart';
+import '../diagnostics/diagnostic_listener.dart';
+import '../elements/elements.dart';
+import '../enqueue.dart';
+import '../universe/selector.dart';
+import '../universe/use.dart';
+import 'backend.dart';
+
+class MirrorsAnalysis {
+  final MirrorsHandler resolutionHandler;
+  final MirrorsHandler codegenHandler;
+
+  MirrorsAnalysis(JavaScriptBackend backend, Resolution resolution)
+      : resolutionHandler = new MirrorsHandler(backend, resolution),
+        codegenHandler = new MirrorsHandler(backend, resolution);
+
+  /// Enqueue all elements that are matched by the mirrors used
+  /// annotation or, in lack thereof, all elements.
+  // TODO(johnniwinther): Compute [WorldImpact] instead of enqueuing directly.
+  void enqueueReflectiveElements(
+      Enqueuer enqueuer,
+      Iterable<ClassElement> recents,
+      Iterable<LibraryElement> loadedLibraries) {
+    MirrorsHandler handler =
+        enqueuer.isResolutionQueue ? resolutionHandler : codegenHandler;
+    handler.enqueueReflectiveElements(enqueuer, recents, loadedLibraries);
+  }
+
+  /// Enqueue the static fields that have been marked as used by reflective
+  /// usage through `MirrorsUsed`.
+  // TODO(johnniwinther): Compute [WorldImpact] instead of enqueuing directly.
+  void enqueueReflectiveStaticFields(
+      Enqueuer enqueuer, Iterable<Element> elements) {
+    MirrorsHandler handler =
+        enqueuer.isResolutionQueue ? resolutionHandler : codegenHandler;
+    handler.enqueueReflectiveStaticFields(enqueuer, elements);
+  }
+}
+
+class MirrorsHandler {
+  static final TRACE_MIRROR_ENQUEUING =
+      const bool.fromEnvironment("TRACE_MIRROR_ENQUEUING");
+
+  final JavaScriptBackend _backend;
+  final Resolution _resolution;
+
+  bool hasEnqueuedReflectiveElements = false;
+  bool hasEnqueuedReflectiveStaticFields = false;
+
+  MirrorsHandler(this._backend, this._resolution);
+
+  DiagnosticReporter get _reporter => _resolution.reporter;
+
+  void _logEnqueueReflectiveAction(action, [msg = ""]) {
+    if (TRACE_MIRROR_ENQUEUING) {
+      print("MIRROR_ENQUEUE (R): $action $msg");
+    }
+  }
+
+  /**
+   * Decides whether an element should be included to satisfy requirements
+   * of the mirror system.
+   *
+   * During resolution, we have to resort to matching elements against the
+   * [MirrorsUsed] pattern, as we do not have a complete picture of the world,
+   * yet.
+   */
+  bool _shouldIncludeElementDueToMirrors(Element element,
+      {bool includedEnclosing}) {
+    return includedEnclosing || _backend.requiredByMirrorSystem(element);
+  }
+
+  /// Enqeue the constructor [ctor] if it is required for reflection.
+  ///
+  /// [enclosingWasIncluded] provides a hint whether the enclosing element was
+  /// needed for reflection.
+  void _enqueueReflectiveConstructor(
+      Enqueuer enqueuer, ConstructorElement constructor,
+      {bool enclosingWasIncluded}) {
+    if (_shouldIncludeElementDueToMirrors(constructor,
+        includedEnclosing: enclosingWasIncluded)) {
+      _logEnqueueReflectiveAction(constructor);
+      ClassElement cls = constructor.declaration.enclosingClass;
+      enqueuer.registerTypeUse(new TypeUse.mirrorInstantiation(cls.rawType));
+      enqueuer
+          .registerStaticUse(new StaticUse.foreignUse(constructor.declaration));
+    }
+  }
+
+  /// Enqeue the member [element] if it is required for reflection.
+  ///
+  /// [enclosingWasIncluded] provides a hint whether the enclosing element was
+  /// needed for reflection.
+  void _enqueueReflectiveMember(
+      Enqueuer enqueuer, Element element, bool enclosingWasIncluded) {
+    if (_shouldIncludeElementDueToMirrors(element,
+        includedEnclosing: enclosingWasIncluded)) {
+      _logEnqueueReflectiveAction(element);
+      if (element.isTypedef) {
+        TypedefElement typedef = element;
+        typedef.ensureResolved(_resolution);
+      } else if (Elements.isStaticOrTopLevel(element)) {
+        enqueuer
+            .registerStaticUse(new StaticUse.foreignUse(element.declaration));
+      } else if (element.isInstanceMember) {
+        // We need to enqueue all members matching this one in subclasses, as
+        // well.
+        // TODO(herhut): Use TypedSelector.subtype for enqueueing
+        DynamicUse dynamicUse =
+            new DynamicUse(new Selector.fromElement(element), null);
+        enqueuer.registerDynamicUse(dynamicUse);
+        if (element.isField) {
+          DynamicUse dynamicUse = new DynamicUse(
+              new Selector.setter(
+                  new Name(element.name, element.library, isSetter: true)),
+              null);
+          enqueuer.registerDynamicUse(dynamicUse);
+        }
+      }
+    }
+  }
+
+  /// Enqeue the member [element] if it is required for reflection.
+  ///
+  /// [enclosingWasIncluded] provides a hint whether the enclosing element was
+  /// needed for reflection.
+  void _enqueueReflectiveElementsInClass(
+      Enqueuer enqueuer, ClassElement cls, Iterable<ClassElement> recents,
+      {bool enclosingWasIncluded}) {
+    if (cls.library.isInternalLibrary || cls.isInjected) return;
+    bool includeClass = _shouldIncludeElementDueToMirrors(cls,
+        includedEnclosing: enclosingWasIncluded);
+    if (includeClass) {
+      _logEnqueueReflectiveAction(cls, "register");
+      ClassElement declaration = cls.declaration;
+      declaration.ensureResolved(_resolution);
+      enqueuer.registerTypeUse(
+          new TypeUse.mirrorInstantiation(declaration.rawType));
+    }
+    // If the class is never instantiated, we know nothing of it can possibly
+    // be reflected upon.
+    // TODO(herhut): Add a warning if a mirrors annotation cannot hit.
+    if (recents.contains(cls.declaration)) {
+      _logEnqueueReflectiveAction(cls, "members");
+      cls.constructors.forEach((Element element) {
+        _enqueueReflectiveConstructor(enqueuer, element,
+            enclosingWasIncluded: includeClass);
+      });
+      cls.forEachClassMember((Member member) {
+        _enqueueReflectiveMember(enqueuer, member.element, includeClass);
+      });
+    }
+  }
+
+  /// Enqeue special classes that might not be visible by normal means or that
+  /// would not normally be enqueued:
+  ///
+  /// [Closure] is treated specially as it is the superclass of all closures.
+  /// Although it is in an internal library, we mark it as reflectable. Note
+  /// that none of its methods are reflectable, unless reflectable by
+  /// inheritance.
+  void _enqueueReflectiveSpecialClasses(Enqueuer enqueuer) {
+    Iterable<ClassElement> classes = _backend.classesRequiredForReflection;
+    for (ClassElement cls in classes) {
+      if (_backend.referencedFromMirrorSystem(cls)) {
+        _logEnqueueReflectiveAction(cls);
+        cls.ensureResolved(_resolution);
+        enqueuer.registerTypeUse(new TypeUse.mirrorInstantiation(cls.rawType));
+      }
+    }
+  }
+
+  /// Enqeue all local members of the library [lib] if they are required for
+  /// reflection.
+  void _enqueueReflectiveElementsInLibrary(
+      Enqueuer enqueuer, LibraryElement lib, Iterable<ClassElement> recents) {
+    bool includeLibrary =
+        _shouldIncludeElementDueToMirrors(lib, includedEnclosing: false);
+    lib.forEachLocalMember((Element member) {
+      if (member.isInjected) return;
+      if (member.isClass) {
+        _enqueueReflectiveElementsInClass(enqueuer, member, recents,
+            enclosingWasIncluded: includeLibrary);
+      } else {
+        _enqueueReflectiveMember(enqueuer, member, includeLibrary);
+      }
+    });
+  }
+
+  /// Enqueue all elements that are matched by the mirrors used
+  /// annotation or, in lack thereof, all elements.
+  // TODO(johnniwinther): Compute [WorldImpact] instead of enqueuing directly.
+  void enqueueReflectiveElements(
+      Enqueuer enqueuer,
+      Iterable<ClassElement> recents,
+      Iterable<LibraryElement> loadedLibraries) {
+    if (!hasEnqueuedReflectiveElements) {
+      _logEnqueueReflectiveAction("!START enqueueAll");
+      // First round of enqueuing, visit everything that is visible to
+      // also pick up static top levels, etc.
+      // Also, during the first round, consider all classes that have been seen
+      // as recently seen, as we do not know how many rounds of resolution might
+      // have run before tree shaking is disabled and thus everything is
+      // enqueued.
+      recents = enqueuer.processedClasses.toSet();
+      _reporter.log('Enqueuing everything');
+      for (LibraryElement lib in loadedLibraries) {
+        _enqueueReflectiveElementsInLibrary(enqueuer, lib, recents);
+      }
+      _enqueueReflectiveSpecialClasses(enqueuer);
+      hasEnqueuedReflectiveElements = true;
+      hasEnqueuedReflectiveStaticFields = true;
+      _logEnqueueReflectiveAction("!DONE enqueueAll");
+    } else if (recents.isNotEmpty) {
+      // Keep looking at new classes until fixpoint is reached.
+      _logEnqueueReflectiveAction("!START enqueueRecents");
+      recents.forEach((ClassElement cls) {
+        _enqueueReflectiveElementsInClass(enqueuer, cls, recents,
+            enclosingWasIncluded: _shouldIncludeElementDueToMirrors(cls.library,
+                includedEnclosing: false));
+      });
+      _logEnqueueReflectiveAction("!DONE enqueueRecents");
+    }
+  }
+
+  /// Enqueue the static fields that have been marked as used by reflective
+  /// usage through `MirrorsUsed`.
+  // TODO(johnniwinther): Compute [WorldImpact] instead of enqueuing directly.
+  void enqueueReflectiveStaticFields(
+      Enqueuer enqueuer, Iterable<Element> elements) {
+    if (hasEnqueuedReflectiveStaticFields) return;
+    hasEnqueuedReflectiveStaticFields = true;
+    for (Element element in elements) {
+      _enqueueReflectiveMember(enqueuer, element, true);
+    }
+  }
+}