Reuse CompilationUnitElement in BuildCompilationUnitElementTask.

pkg/analyzer/lib/src/task/dart.dart

 // Copyright (c) 2015, 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 analyzer.src.task.dart;
 
 import 'dart:collection';
 import 'dart:math' as math;
 
+import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/constant.dart';
 import 'package:analyzer/src/generated/element.dart';
-import 'package:analyzer/src/generated/engine.dart' hide AnalysisTask;
+import 'package:analyzer/src/generated/engine.dart'
+    hide AnalysisCache, AnalysisTask;
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/error_verifier.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/task/driver.dart';
 import 'package:analyzer/src/task/general.dart';
@@ skipping 637 matching lines @@
 
   @override
   void internalPerform() {
     //
     // Prepare inputs.
     //
     LibrarySpecificUnit librarySpecificUnit = target;
     Source source = getRequiredSource();
     CompilationUnit unit = getRequiredInput(PARSED_UNIT_INPUT_NAME);
     //
-    // Process inputs.
+    // Build or reuse CompilationUnitElement.
     //
     unit = AstCloner.clone(unit);
-    CompilationUnitBuilder builder = new CompilationUnitBuilder();
+    AnalysisCache analysisCache =
+        (context as InternalAnalysisContext).analysisCache;
     CompilationUnitElement element =
-        builder.buildCompilationUnit(source, unit, librarySpecificUnit.library);
+        analysisCache.getValue(target, COMPILATION_UNIT_ELEMENT);
+    if (element == null) {
+      CompilationUnitBuilder builder = new CompilationUnitBuilder();
+      element = builder.buildCompilationUnit(
+          source, unit, librarySpecificUnit.library);
+    } else {
+      new DeclarationResolver().resolve(unit, element);
+    }
+    //
+    // Prepare constants.
+    //
     ConstantFinder constantFinder =
         new ConstantFinder(context, source, librarySpecificUnit.library);
     unit.accept(constantFinder);
     List<ConstantEvaluationTarget> constants =
         new List<ConstantEvaluationTarget>.from(
             constantFinder.constantsToCompute);
     //
     // Record outputs.
     //
     outputs[COMPILATION_UNIT_ELEMENT] = element;
@@ skipping 2659 matching lines @@
   @override
   bool moveNext() {
     if (_newSources.isEmpty) {
       return false;
     }
     currentTarget = _newSources.first;
     _newSources.remove(currentTarget);
     return true;
   }
 }