Refactor handling of source map information.

pkg/compiler/lib/src/js_backend/codegen/task.dart

 // 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.
 
 /// Generate code using the cps-based IR pipeline.
 library code_generator_task;
 
 import 'glue.dart';
 import 'codegen.dart';
 import 'unsugar.dart';
 
 import '../js_backend.dart';
 import '../../dart2jslib.dart';
-import '../../io/source_file.dart';
 import '../../cps_ir/cps_ir_nodes.dart' as cps;
 import '../../cps_ir/cps_ir_builder.dart';
 import '../../tree_ir/tree_ir_nodes.dart' as tree_ir;
-import '../../tree/tree.dart' as ast;
 import '../../types/types.dart' show TypeMask, UnionTypeMask, FlatTypeMask,
     ForwardingTypeMask;
-import '../../scanner/scannerlib.dart' as scanner;
 import '../../elements/elements.dart';
 import '../../js/js.dart' as js;
-import '../../io/source_map_builder.dart';
+import '../../io/source_information.dart' show StartEndSourceInformation;
 import '../../tree_ir/tree_ir_builder.dart' as tree_builder;
 import '../../dart_backend/backend_ast_emitter.dart' as backend_ast_emitter;
 import '../../cps_ir/optimizers.dart';
 import '../../tracer.dart';
 import '../../js_backend/codegen/codegen.dart';
 import '../../ssa/ssa.dart' as ssa;
 import '../../tree_ir/optimization/optimization.dart';
 import '../../cps_ir/cps_ir_nodes_sexpr.dart';
 import 'js_tree_builder.dart';
 
@@ skipping 165 matching lines @@
 
     return attachPosition(codeGen.buildFunction(definition), work.element);
   }
 
   Iterable<CompilerTask> get tasks {
     // TODO(sigurdm): Make a better list of tasks.
     return <CompilerTask>[irBuilderTask]..addAll(fallbackCompiler.tasks);
   }
 
   js.Node attachPosition(js.Node node, AstElement element) {
-    // TODO(sra): Attaching positions might be cleaner if the source position
-    // was on a wrapping node.
-    SourceFile sourceFile = sourceFileOfElement(element);
-    String name = element.name;
-    AstElement implementation = element.implementation;
-    ast.Node expression = implementation.node;
-    scanner.Token beginToken;
-    scanner.Token endToken;
-    if (expression == null) {
-      // Synthesized node. Use the enclosing element for the location.
-      beginToken = endToken = element.position;
-    } else {
-      beginToken = expression.getBeginToken();
-      endToken = expression.getEndToken();
-    }
-    // TODO(podivilov): find the right sourceFile here and remove offset
-    // checks below.
-    var sourcePosition, endSourcePosition;
-    if (beginToken.charOffset < sourceFile.length) {
-      sourcePosition =
-          new TokenSourceFileLocation(sourceFile, beginToken, name);
-    }
-    if (endToken.charOffset < sourceFile.length) {
-      endSourcePosition =
-          new TokenSourceFileLocation(sourceFile, endToken, name);
-    }
-    return node.withPosition(sourcePosition, endSourcePosition);
-  }
-
-  SourceFile sourceFileOfElement(Element element) {
-    return element.implementation.compilationUnit.script.file;
+    return node.withSourceInformation(
+        StartEndSourceInformation.computeSourceInformation(element));
   }
 }