dart2js: restructure emitter.

sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.dart

 // Copyright (c) 2012, 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;
 
 const USE_NEW_EMITTER = const bool.fromEnvironment("dart2js.use.new.emitter");
 
 /**
  * Generates the code for all used classes in the program. Static fields (even
  * in classes) are ignored, since they can be treated as non-class elements.
  *
  * The code for the containing (used) methods must exist in the [:universe:].
  */
 class CodeEmitterTask extends CompilerTask {
   // TODO(floitsch): the code-emitter task should not need a namer.
   final Namer namer;
   final TypeTestEmitter typeTestEmitter = new TypeTestEmitter();
   NativeEmitter nativeEmitter;
   OldEmitter oldEmitter;
   Emitter emitter;
 
   final Set<ClassElement> neededClasses = new Set<ClassElement>();
   final Map<OutputUnit, List<ClassElement>> outputClassLists =
       new Map<OutputUnit, List<ClassElement>>();
   final Map<OutputUnit, List<ConstantValue>> outputConstantLists =
       new Map<OutputUnit, List<ConstantValue>>();
+  final Map<OutputUnit, List<Element>> outputStaticLists =
+      new Map<OutputUnit, List<Element>>();
+  final Map<OutputUnit, Set<LibraryElement>> outputLibraryLists =
+      new Map<OutputUnit, Set<LibraryElement>>();
+
+  /// True, if the output contains a constant list.
+  ///
+  /// This flag is updated in [computeNeededConstants].
+  bool outputContainsConstantList = false;
+
   final List<ClassElement> nativeClasses = <ClassElement>[];
 
   /// Records if a type variable is read dynamically for type tests.
   final Set<TypeVariableElement> readTypeVariables =
       new Set<TypeVariableElement>();
 
   List<TypedefElement> typedefsNeededForReflection;
 
   JavaScriptBackend get backend => compiler.backend;
 
@@ skipping 118 matching lines @@
         }
       }
       typedefsNeededForReflection.forEach(backend.retainMetadataOf);
     }
 
     JavaScriptConstantCompiler handler = backend.constants;
     List<ConstantValue> constants = handler.getConstantsForEmission(
         compiler.hasIncrementalSupport ? null : emitter.compareConstants);
     for (ConstantValue constant in constants) {
       if (emitter.isConstantInlinedOrAlreadyEmitted(constant)) continue;
+
+      if (constant.isList) outputContainsConstantList = true;
+
       OutputUnit constantUnit =
           compiler.deferredLoadTask.outputUnitForConstant(constant);
       if (constantUnit == null) {
         // The back-end introduces some constants, like "InterceptorConstant" or
         // some list constants. They are emitted in the main output-unit.
         // TODO(sigurdm): We should track those constants.
         constantUnit = compiler.deferredLoadTask.mainOutputUnit;
       }
       outputConstantLists.putIfAbsent(
           constantUnit, () => new List<ConstantValue>()).add(constant);
@@ skipping 103 matching lines @@
         }
       } else {
         outputClassLists.putIfAbsent(
             compiler.deferredLoadTask.outputUnitForElement(element),
             () => new List<ClassElement>())
             .add(element);
       }
     }
   }
 
+  void computeNeededStatics() {
+    bool isStaticFunction(Element element) =>
+        !element.isInstanceMember && !element.isField;
+
+    Iterable<Element> elements =
+        backend.generatedCode.keys.where(isStaticFunction);
+
+    for (Element element in Elements.sortedByPosition(elements)) {
+      outputStaticLists.putIfAbsent(
+          compiler.deferredLoadTask.outputUnitForElement(element),
+          () => new List<Element>())
+          .add(element);
+    }
+  }
+
+  void computeNeededLibraries() {
+    void addSurroundingLibraryToSet(Element element) {
+      OutputUnit unit = compiler.deferredLoadTask.outputUnitForElement(element);
+      LibraryElement library = element.library;
+      outputLibraryLists.putIfAbsent(unit, () => new Set<LibraryElement>())
+          .add(library);
+    }
+
+    backend.generatedCode.keys.forEach(addSurroundingLibraryToSet);
+    neededClasses.forEach(addSurroundingLibraryToSet);
+}
+
   void assembleProgram() {
     measure(() {
       emitter.invalidateCaches();
 
       // Compute the required type checks to know which classes need a
       // 'is$' method.
       typeTestEmitter.computeRequiredTypeChecks();
 
       computeNeededDeclarations();
       computeNeededConstants();
+      computeNeededStatics();
+      computeNeededLibraries();
+
 
       Program program;
       if (USE_NEW_EMITTER) {
         program = new ProgramBuilder(compiler, namer, this).buildProgram();
       }
       emitter.emitProgram(program);
     });
   }
 }
 
 abstract class Emitter {
   void emitProgram(Program program);
 
   jsAst.Expression generateEmbeddedGlobalAccess(String global);
   jsAst.Expression constantReference(ConstantValue value);
 
   int compareConstants(ConstantValue a, ConstantValue b);
   bool isConstantInlinedOrAlreadyEmitted(ConstantValue constant);
 
   void invalidateCaches();
 }