Add Dart code to diff_view

tests/compiler/dart2js/sourcemaps/diff_view.dart

-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// 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 sourcemap.diff_view;
 
 import 'dart:async';
+import 'dart:convert';
 import 'dart:io';
+
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/diagnostics/invariant.dart';
+import 'package:compiler/src/elements/elements.dart';
 import 'package:compiler/src/io/position_information.dart';
+import 'package:compiler/src/io/source_information.dart';
+import 'package:compiler/src/io/source_file.dart';
 import 'package:compiler/src/js/js.dart' as js;
+import 'package:compiler/src/js/js_debug.dart';
+
+import 'diff.dart';
+import 'html_parts.dart';
+import 'js_tracer.dart';
+import 'output_structure.dart';
 import 'sourcemap_helper.dart';
 import 'sourcemap_html_helper.dart';
 import 'trace_graph.dart';
-import 'js_tracer.dart';
 
-const String WITH_SOURCE_INFO_STYLE = 'background-color:#FF8080;';
-const String WITHOUT_SOURCE_INFO_STYLE = 'border: solid 1px #FF8080;';
-const String ADDITIONAL_SOURCE_INFO_STYLE = 'border: solid 1px #8080FF;';
+const String WITH_SOURCE_INFO_STYLE = 'border: solid 1px #FF8080;';
+const String WITHOUT_SOURCE_INFO_STYLE = 'background-color: #8080FF;';
+const String ADDITIONAL_SOURCE_INFO_STYLE = 'border: solid 1px #80FF80;';
+const String UNUSED_SOURCE_INFO_STYLE = 'border: solid 1px #8080FF;';
 
 main(List<String> args) async {
   DEBUG_MODE = true;
   String out = 'out.js.diff_view.html';
   String filename;
   List<String> currentOptions = [];
-  List<List<String>> options = [currentOptions];
+  List<List<String>> optionSegments = [currentOptions];
+  Map<int, String> loadFrom = {};
+  Map<int, String> saveTo = {};
   int argGroup = 0;
   bool addAnnotations = true;
   for (String arg in args) {
     if (arg == '--') {
       currentOptions = [];
-      options.add(currentOptions);
+      optionSegments.add(currentOptions);
       argGroup++;
     } else if (arg == '-h') {
       addAnnotations = false;
       print('Hiding annotations');
+    } else if (arg == '-l') {
+      loadFrom[argGroup] = 'out.js.diff$argGroup.json';
+    } else if (arg.startsWith('--load=')) {
+      loadFrom[argGroup] = arg.substring('--load='.length);
+    } else if (arg == '-s') {
+      saveTo[argGroup] = 'out.js.diff$argGroup.json';
+    } else if (arg.startsWith('--save=')) {
+      saveTo[argGroup] = arg.substring('--save='.length);
     } else if (arg.startsWith('-o')) {
       out = arg.substring('-o'.length);
     } else if (arg.startsWith('--out=')) {
       out = arg.substring('--out='.length);
     } else if (arg.startsWith('-')) {
       currentOptions.add(arg);
     } else {
       filename = arg;
     }
   }
-  List<String> commonArguments = options[0];
-  List<String> options1;
-  List<String> options2;
-  if (options.length == 1) {
+  List<String> commonArguments = optionSegments[0];
+  List<List<String>> options = <List<String>>[];
+  if (optionSegments.length == 1) {
     // Use default options; comparing SSA and CPS output using the new
     // source information strategy.
-    options1 = [USE_NEW_SOURCE_INFO]..addAll(commonArguments);
-    options2 = [USE_NEW_SOURCE_INFO, Flags.useCpsIr]..addAll(commonArguments);
-  } else if (options.length == 2) {
+    options.add([USE_NEW_SOURCE_INFO]..addAll(commonArguments));
+    options.add([USE_NEW_SOURCE_INFO, Flags.useCpsIr]..addAll(commonArguments));
+  } else if (optionSegments.length == 2) {
     // Use alternative options for the second output column.
-    options1 = commonArguments;
-    options2 = options[1]..addAll(commonArguments);
+    options.add(commonArguments);
+    options.add(optionSegments[1]..addAll(commonArguments));
   } else {
     // Use specific options for both output columns.
-    options1 = options[1]..addAll(commonArguments);
-    options2 = options[2]..addAll(commonArguments);
+    options.add(optionSegments[1]..addAll(commonArguments));
+    options.add(optionSegments[2]..addAll(commonArguments));
   }
 
-  print('Compiling ${options1.join(' ')} $filename');
-  CodeLinesResult result1 = await computeCodeLines(
-      options1, filename, addAnnotations: addAnnotations);
-  print('Compiling ${options2.join(' ')} $filename');
-  CodeLinesResult result2 = await computeCodeLines(
-      options2, filename, addAnnotations: addAnnotations);
+  SourceFileManager sourceFileManager = new IOSourceFileManager(Uri.base);
+  List<AnnotatedOutput> outputs = <AnnotatedOutput>[];
+  for (int i = 0; i < 2; i++) {
+    AnnotatedOutput output;
+    if (loadFrom.containsKey(i)) {
+      output = AnnotatedOutput.loadOutput(loadFrom[i]);
+    } else {
+      print('Compiling ${options[i].join(' ')} $filename');
+      CodeLinesResult result = await computeCodeLines(
+          options[i], filename, addAnnotations: addAnnotations);
+      OutputStructure structure = OutputStructure.parse(result.codeLines);
+      computeEntityCodeSources(result, structure);
+      output = new AnnotatedOutput(
+          filename,
+          options[i],
+          structure,
+          result.coverage.getCoverageReport());
+    }
+    if (saveTo.containsKey(i)) {
+      AnnotatedOutput.saveOutput(output, saveTo[i]);
+    }
+    outputs.add(output);
+  }
+
+  List<DiffBlock> blocks = createDiffBlocks(
+      outputs.map((o) => o.structure).toList(),
+      sourceFileManager);
+
+  outputDiffView(
+      out, outputs, blocks, addAnnotations: addAnnotations);
+}
+
+/// Attaches [CodeSource]s to the entities in [structure] using the
+/// element-to-offset in [result].
+void computeEntityCodeSources(
+    CodeLinesResult result, OutputStructure structure) {
+  result.elementMap.forEach((int line, Element element) {
+    OutputEntity entity = structure.getEntityForLine(line);
+    if (entity != null) {
+      entity.codeSource = codeSourceFromElement(element);
+    }
+  });
+}
+
+/// The structured output of a compilation.
+class AnnotatedOutput {
+  final String filename;
+  final List<String> options;
+  final OutputStructure structure;
+  final String coverage;
+
+  AnnotatedOutput(this.filename, this.options, this.structure, this.coverage);
+
+  List<CodeLine> get codeLines => structure.lines;
+
+  Map toJson() {
+    return {
+      'filename': filename,
+      'options': options,
+      'structure': structure.toJson(),
+      'coverage': coverage,
+    };
+  }
+
+  static AnnotatedOutput fromJson(Map json) {
+    String filename = json['filename'];
+    List<String> options = json['options'];
+    OutputStructure structure = OutputStructure.fromJson(json['structure']);
+    String coverage = json['coverage'];
+    return new AnnotatedOutput(filename, options, structure, coverage);
+  }
+
+  static AnnotatedOutput loadOutput(filename) {
+    AnnotatedOutput output = AnnotatedOutput.fromJson(
+        JSON.decode(new File(filename).readAsStringSync()));
+    print('Output loaded from $filename');
+    return output;
+  }
+
+  static void saveOutput(AnnotatedOutput output, String filename) {
+    if (filename != null) {
+      new File(filename).writeAsStringSync(
+          const JsonEncoder.withIndent('  ').convert(output.toJson()));
+      print('Output saved in $filename');
+    }
+  }
+}
+
+void outputDiffView(
+    String out,
+    List<AnnotatedOutput> outputs,
+    List<DiffBlock> blocks,
+    {bool addAnnotations: true}) {
+  assert(outputs[0].filename == outputs[1].filename);
+  bool usePre = true;
 
   StringBuffer sb = new StringBuffer();
   sb.write('''
 <html>
 <head>
-<title>Diff for $filename</title>
+<title>Diff for ${outputs[0].filename}</title>
 <style>
 .lineNumber {
   font-size: smaller;
   color: #888;
 }
+.comment {
+  font-size: smaller;
+  color: #888;
+  font-family: initial;
+}
 .header {
   position: fixed;
-  width: 50%;
+  width: 100%;
+  background-color: #FFFFFF;
+  left: 0px;
+  top: 0px;
+  height: 42px;
+  z-index: 1000;
+}
+.header-table {
+  width: 100%;
   background-color: #400000;
   color: #FFFFFF;
-  height: 20px;
-  top: 0px;
-  z-index: 1000;
+  border-spacing: 0px;
+}
+.header-column {
+  width: 34%;
+}
+.legend {
+  padding: 2px;
+}
+.table {
+  position: absolute;
+  left: 0px;
+  top: 42px;
+  width: 100%;
+  border-spacing: 0px;
 }
 .cell {
-  max-width:500px;
-  overflow-x:auto;
-  vertical-align:top;
+  max-width: 500px;
+  overflow-y: hidden;
+  vertical-align: top;
+  border-top: 1px solid #F0F0F0;
+  border-left: 1px solid #F0F0F0;
+''');
+  if (usePre) {
+    sb.write('''
+  overflow-x: hidden;
+  white-space: pre-wrap;
+''');
+  } else {
+    sb.write('''
+  overflow-x: hidden;
+  padding-left: 100px;
+  text-indent: -100px;
+''');
+  }
+  sb.write('''
+  font-family: monospace;
+  padding: 0px;
 }
 .corresponding1 {
   background-color: #FFFFE0;
 }
 .corresponding2 {
   background-color: #EFEFD0;
 }
 .identical1 {
   background-color: #E0F0E0;
 }
 .identical2 {
   background-color: #C0E0C0;
 }
+.line {
+  padding-left: 7em;
+  text-indent: -7em;
+  margin: 0px;
+}
+.column0 {
+}
+.column1 {
+}
+.column2 {
+}
 </style>
 </head>
 <body>''');
 
   sb.write('''
-<div class="header" style="left: 0px;">[${options1.join(',')}]</div>
-<div class="header" style="right: 0px;">[${options2.join(',')}]</div>
-<div style="position:absolute;left:0px;top:22px;width:100%;height:18px;">
+<div class="header">
+<table class="header-table"><tr>
+<td class="header-column">[${outputs[0].options.join(',')}]</td>
+<td class="header-column">[${outputs[1].options.join(',')}]</td>
+<td class="header-column">Dart code</td>
+</tr></table>
+<div class="legend">
   <span class="identical1">&nbsp;&nbsp;&nbsp;</span> 
   <span class="identical2">&nbsp;&nbsp;&nbsp;</span>
   identical blocks
   <span class="corresponding1">&nbsp;&nbsp;&nbsp;</span>
   <span class="corresponding2">&nbsp;&nbsp;&nbsp;</span> 
   corresponding blocks
 ''');
+
   if (addAnnotations) {
     sb.write('''
   <span style="$WITH_SOURCE_INFO_STYLE">&nbsp;&nbsp;&nbsp;</span>
-  offset with source information
+  <span title="'offset with source information' means that source information 
+is available for an offset which is expected to have a source location 
+attached. This offset has source information as intended.">
+  offset with source information</span>
   <span style="$WITHOUT_SOURCE_INFO_STYLE">&nbsp;&nbsp;&nbsp;</span>
-  offset without source information
+  <span title="'offset without source information' means that _no_ source 
+information is available for an offset which was expected to have a source 
+location attached. Source information must be found for this offset.">
+  offset without source information</span>
   <span style="$ADDITIONAL_SOURCE_INFO_STYLE">&nbsp;&nbsp;&nbsp;</span>
-  offset with unneeded source information
+  <span title="'offset with unneeded source information' means that a source 
+location was attached to an offset which was _not_ expected to have a source
+location attached. The source location should be removed from this offset.">
+  offset with unneeded source information</span>
+  <span style="$UNUSED_SOURCE_INFO_STYLE">&nbsp;&nbsp;&nbsp;</span>
+  <span title="'offset with unused source information' means that source 
+information is available for an offset which is _not_ expected to have a source
+location attached. This source information _could_ be used by a parent AST node
+offset that is an 'offset without source information'."> 
+  offset with unused source information</span>
 ''');
   }
+
   sb.write('''
-</div>
-<table style="position:absolute;left:0px;top:40px;width:100%;"><tr>
+</div></div>
+<table class="table">
 ''');
 
   void addCell(String content) {
     sb.write('''
 <td class="cell"><pre>
 ''');
     sb.write(content);
     sb.write('''
 </pre></td>
 ''');
   }
 
-  List<OutputStructure> structures = [
-      OutputStructure.parse(result1.codeLines),
-      OutputStructure.parse(result2.codeLines)];
-  List<List<CodeLine>> inputLines = [result1.codeLines, result2.codeLines];
-  List<List<HtmlPart>> outputLines = [<HtmlPart>[], <HtmlPart>[]];
-
   /// Marker to alternate output colors.
   bool alternating = false;
 
-  /// Enable 'corresponding' background colors for [f].
-  void withMatching(f()) {
-    HtmlPart start = new ConstHtmlPart(
-        '<div class="corresponding${alternating ? '1' : '2'}">');
-    HtmlPart end = new ConstHtmlPart('</div>');
-    alternating = !alternating;
-    outputLines[0].add(start);
-    outputLines[1].add(start);
-    f();
-    outputLines[0].add(end);
-    outputLines[1].add(end);
+  List<HtmlPrintContext> printContexts = <HtmlPrintContext>[];
+  for (int i = 0; i < 2; i++) {
+    int lineNoWidth;
+    if (outputs[i].codeLines.isNotEmpty) {
+      lineNoWidth = '${outputs[i].codeLines.last.lineNo + 1}'.length;
+    }
+    printContexts.add(new HtmlPrintContext(lineNoWidth: lineNoWidth));
   }
 
-  /// Enable 'identical' background colors for [f].
-  void withIdentical(f()) {
-    HtmlPart start = new ConstHtmlPart(
-        '<div class="identical${alternating ? '1' : '2'}">');
-    HtmlPart end = new ConstHtmlPart('</div>');
-    alternating = !alternating;
-    outputLines[0].add(start);
-    outputLines[1].add(start);
-    f();
-    outputLines[0].add(end);
-    outputLines[1].add(end);
+  for (DiffBlock block in blocks) {
+    String className;
+    switch (block.kind) {
+      case DiffKind.UNMATCHED:
+        className = 'cell';
+        break;
+      case DiffKind.MATCHING:
+        className = 'cell corresponding${alternating ? '1' : '2'}';
+        alternating = !alternating;
+        break;
+      case DiffKind.IDENTICAL:
+        className = 'cell identical${alternating ? '1' : '2'}';
+        alternating = !alternating;
+        break;
+    }
+    sb.write('<tr>');
+    for (int index = 0; index < 3; index++) {
+      sb.write('''<td class="$className column$index">''');
+      List<HtmlPart> lines = block.getColumn(index);
+      if (lines.isNotEmpty) {
+        for (HtmlPart line in lines) {
+          sb.write('<p class="line">');
+          if (index < printContexts.length) {
+            line.printHtmlOn(sb, printContexts[index]);
+          } else {
+            line.printHtmlOn(sb, new HtmlPrintContext());
+          }
+          sb.write('</p>');
+        }
+      }
+      sb.write('''</td>''');
+    }
+    sb.write('</tr>');
   }
 
-  /// Output code lines in [range] from input number [index], padding the other
-  /// column with empty lines.
-  void handleSkew(int index, Interval range) {
-    int from = range.from;
-    while (from < range.to) {
-      outputLines[1 - index].add(const ConstHtmlPart('\n'));
-      outputLines[index].add(
-          new CodeLineHtmlPart(inputLines[index][from++]));
-    }
-  }
+  sb.write('''</tr><tr>''');
 
-  /// Output code lines of the [indices] from the corresponding inputs.
-  void addBoth(List<int> indices) {
-    outputLines[0].add(new CodeLineHtmlPart(inputLines[0][indices[0]]));
-    outputLines[1].add(new CodeLineHtmlPart(inputLines[1][indices[1]]));
-  }
-
-  /// Output code lines of the [ranges] from the corresponding inputs.
-  void addBothLines(List<Interval> ranges) {
-    Interval range1 = ranges[0];
-    Interval range2 = ranges[1];
-    int offset = 0;
-    while (range1.from + offset < range1.to &&
-           range2.from + offset < range2.to) {
-      addBoth([range1.from + offset, range2.from + offset]);
-      offset++;
-    }
-    if (range1.from + offset < range1.to) {
-      handleSkew(0, new Interval(range1.from + offset, range1.to));
-    }
-    if (range2.from + offset < range2.to) {
-      handleSkew(1, new Interval(range2.from + offset, range2.to));
-    }
-  }
-
-  /// Merge the code lines in [range1] and [range2] of the corresponding input.
-  void addRaw(Interval range1, Interval range2) {
-    match(a, b) => a.code == b.code;
-
-    List<Interval> currentMatchedIntervals;
-
-    void flushMatching() {
-      if (currentMatchedIntervals != null) {
-        withIdentical(() {
-          addBothLines(currentMatchedIntervals);
-        });
-      }
-      currentMatchedIntervals = null;
-    }
-
-    align(
-        inputLines[0],
-        inputLines[1],
-        range1: range1,
-        range2: range2,
-        match: match,
-        handleSkew: (int listIndex, Interval range) {
-          flushMatching();
-          handleSkew(listIndex, range);
-        },
-        handleMatched: (List<int> indices) {
-          if (currentMatchedIntervals == null) {
-            currentMatchedIntervals = [
-              new Interval(indices[0], indices[0] + 1),
-              new Interval(indices[1], indices[1] + 1)];
-          } else {
-            currentMatchedIntervals[0] =
-                new Interval(currentMatchedIntervals[0].from, indices[0] + 1);
-            currentMatchedIntervals[1] =
-                new Interval(currentMatchedIntervals[1].from, indices[1] + 1);
-          }
-        },
-        handleUnmatched: (List<int> indices) {
-          flushMatching();
-          addBoth(indices);
-        });
-
-    flushMatching();
-  }
-
-  /// Output the lines of the library blocks in [childRange] in
-  /// `structures[index]`, padding the other column with empty lines.
-  void addBlock(int index, Interval childRange) {
-    handleSkew(index, structures[index].getChildInterval(childRange));
-  }
-
-  /// Output the members of the [classes] aligned.
-  void addMatchingClasses(List<LibraryClass> classes) {
-    withMatching(() {
-      addBothLines(classes.map((c) => c.header).toList());
-    });
-    align(classes[0].children, classes[1].children,
-        match: (a, b) => a.name == b.name,
-        handleSkew: (int listIndex, Interval childRange) {
-          handleSkew(listIndex,
-              classes[listIndex].getChildInterval(childRange));
-        },
-        handleMatched: (List<int> indices) {
-          List<Interval> intervals =  [
-              classes[0].getChild(indices[0]).interval,
-              classes[1].getChild(indices[1]).interval];
-          withMatching(() {
-            addBothLines(intervals);
-          });
-        },
-        handleUnmatched: (List<int> indices) {
-          List<Interval> intervals =  [
-              classes[0].getChild(indices[0]).interval,
-              classes[1].getChild(indices[1]).interval];
-          addBothLines(intervals);
-        });
-    withMatching(() {
-      addBothLines(classes.map((c) => c.footer).toList());
-    });
-  }
-
-  /// Output the library blocks in [indices] from the corresponding
-  /// [OutputStructure]s, aligning their content.
-  void addMatchingBlocks(List<int> indices) {
-    List<LibraryBlock> blocks = [
-      structures[0].getChild(indices[0]),
-      structures[1].getChild(indices[1])];
-
-    withMatching(() {
-      addBothLines(blocks.map((b) => b.header).toList());
-    });
-    align(blocks[0].children, blocks[1].children,
-        match: (a, b) => a.name == b.name,
-        handleSkew: (int listIndex, Interval childRange) {
-          handleSkew(listIndex, blocks[listIndex].getChildInterval(childRange));
-        },
-        handleMatched: (List<int> indices) {
-          List<BasicEntity> entities =  [
-              blocks[0].getChild(indices[0]),
-              blocks[1].getChild(indices[1])];
-          if (entities.every((e) => e is LibraryClass)) {
-            addMatchingClasses(entities);
-          } else {
-            withMatching(() {
-              addBothLines(entities.map((e) => e.interval).toList());
-            });
-          }
-        },
-        handleUnmatched: (List<int> indices) {
-          List<Interval> intervals =  [
-              blocks[0].getChild(indices[0]).interval,
-              blocks[1].getChild(indices[1]).interval];
-          addBothLines(intervals);
-        });
-    withMatching(() {
-      addBothLines(blocks.map((b) => b.footer).toList());
-    });
-  }
-
-  /// Output the lines of the blocks in [indices] from the corresponding
-  /// [OutputStructure]s.
-  void addUnmatchedBlocks(List<int> indices) {
-    List<LibraryBlock> blocks = [
-       structures[0].getChild(indices[0]),
-       structures[1].getChild(indices[1])];
-    addBothLines([blocks[0].interval, blocks[1].interval]);
-  }
-
-
-  addRaw(structures[0].header, structures[1].header);
-
-  align(structures[0].children,
-        structures[1].children,
-        match: (a, b) => a.name == b.name,
-        handleSkew: addBlock,
-        handleMatched: addMatchingBlocks,
-        handleUnmatched: addUnmatchedBlocks);
-
-  addRaw(structures[0].footer, structures[1].footer);
-
-  addCell(htmlPartsToString(outputLines[0], inputLines[0]));
-  addCell(htmlPartsToString(outputLines[1], inputLines[1]));
-
-  sb.write('''</tr><tr>''');
-  addCell(result1.coverage.getCoverageReport());
-  addCell(result2.coverage.getCoverageReport());
+  addCell(outputs[0].coverage);
+  addCell(outputs[1].coverage);
 
   sb.write('''
-</tr></table>
+</table>
 </body>
 </html>
 ''');
 
   new File(out).writeAsStringSync(sb.toString());
   print('Diff generated in $out');
 }
 
-/// Align the content of [list1] and [list2].
-///
-/// If provided, [range1] and [range2] aligned the subranges of [list1] and
-/// [list2], otherwise the whole lists are aligned.
-///
-/// If provided, [match] determines the equality between members of [list1] and
-/// [list2], otherwise `==` is used.
-///
-/// [handleSkew] is called when a subrange of one list is not found in the
-/// other.
-///
-/// [handleMatched] is called when two indices match up.
-///
-/// [handleUnmatched] is called when two indices don't match up (none are found
-/// in the other list).
-void align(List list1,
-           List list2,
-           {Interval range1,
-            Interval range2,
-            bool match(a, b),
-            void handleSkew(int listIndex, Interval range),
-            void handleMatched(List<int> indices),
-            void handleUnmatched(List<int> indices)}) {
-  if (match == null) {
-    match = (a, b) => a == b;
-  }
-
-  if (range1 == null) {
-    range1 = new Interval(0, list1.length);
-  }
-  if (range2 == null) {
-    range2 = new Interval(0, list2.length);
-  }
-
-  Interval findInOther(
-      List thisLines, Interval thisRange,
-      List otherLines, Interval otherRange) {
-    for (int index = otherRange.from; index < otherRange.to; index++) {
-      if (match(thisLines[thisRange.from], otherLines[index])) {
-        int offset = 1;
-        while (thisRange.from + offset < thisRange.to &&
-               otherRange.from + offset < otherRange.to &&
-               match(thisLines[thisRange.from + offset],
-                     otherLines[otherRange.from + offset])) {
-          offset++;
-        }
-        return new Interval(index, index + offset);
-      }
-    }
-    return null;
-  }
-
-  int start1 = range1.from;
-  int end1 = range1.to;
-  int start2 = range2.from;
-  int end2 = range2.to;
-
-  const int ALIGN1 = -1;
-  const int UNMATCHED = 0;
-  const int ALIGN2 = 1;
-
-  while (start1 < end1 && start2 < end2) {
-    if (match(list1[start1], list2[start2])) {
-      handleMatched([start1++, start2++]);
-    } else {
-      Interval subrange1 = new Interval(start1, end1);
-      Interval subrange2 = new Interval(start2, end2);
-      Interval element2inList1 =
-          findInOther(list1, subrange1, list2, subrange2);
-      Interval element1inList2 =
-          findInOther(list2, subrange2, list1, subrange1);
-      int choice = 0;
-      if (element2inList1 != null) {
-        if (element1inList2 != null) {
-          if (element1inList2.length > 1 && element2inList1.length > 1) {
-            choice =
-                element2inList1.from < element1inList2.from ? ALIGN2 : ALIGN1;
-          } else if (element2inList1.length > 1) {
-            choice = ALIGN2;
-          } else if (element1inList2.length > 1) {
-            choice = ALIGN1;
-          } else {
-            choice =
-                element2inList1.from < element1inList2.from ? ALIGN2 : ALIGN1;
-          }
-        } else {
-          choice = ALIGN2;
-        }
-      } else if (element1inList2 != null) {
-        choice = ALIGN1;
-      }
-      switch (choice) {
-        case ALIGN1:
-          handleSkew(0, new Interval(start1, element1inList2.from));
-          start1 = element1inList2.from;
-          break;
-        case ALIGN2:
-          handleSkew(1, new Interval(start2, element2inList1.from));
-          start2 = element2inList1.from;
-          break;
-        case UNMATCHED:
-          handleUnmatched([start1++, start2++]);
-          break;
-      }
-    }
-  }
-  if (start1 < end1) {
-    handleSkew(0, new Interval(start1, end1));
-  }
-  if (start2 < end2) {
-    handleSkew(1, new Interval(start2, end2));
-  }
-}
-
-// Constants used to identify the subsection of the JavaScript output. These
-// are specifically for the unminified full_emitter output.
-const String HEAD = '  var dart = [';
-const String TAIL = '  }], ';
-const String END = '  setupProgram(dart';
-
-final RegExp TOP_LEVEL_VALUE = new RegExp(r'^    (".+?"):');
-final RegExp TOP_LEVEL_FUNCTION =
-    new RegExp(r'^    ([a-zA-Z0-9_$]+): \[?function');
-final RegExp TOP_LEVEL_CLASS = new RegExp(r'^    ([a-zA-Z0-9_$]+): \[?\{');
-
-final RegExp MEMBER_VALUE = new RegExp(r'^      (".+?"):');
-final RegExp MEMBER_FUNCTION =
-    new RegExp(r'^      ([a-zA-Z0-9_$]+): \[?function');
-final RegExp MEMBER_OBJECT = new RegExp(r'^      ([a-zA-Z0-9_$]+): \[?\{');
-
-/// Subrange of the JavaScript output.
-abstract class OutputEntity {
-  Interval get interval;
-  Interval get header;
-  Interval get footer;
-
-  List<OutputEntity> get children;
-
-  Interval getChildInterval(Interval childIndex) {
-    return new Interval(
-        children[childIndex.from].interval.from,
-        children[childIndex.to - 1].interval.to);
-
-  }
-
-  OutputEntity getChild(int index) {
-    return children[index];
-  }
-}
-
-/// The whole JavaScript output.
-class OutputStructure extends OutputEntity {
-  final List<CodeLine> lines;
-  final int headerEnd;
-  final int footerStart;
-  final List<LibraryBlock> children;
-
-  OutputStructure(
-      this.lines,
-      this.headerEnd,
-      this.footerStart,
-      this.children);
-
-  Interval get interval => new Interval(0, lines.length);
-
-  Interval get header => new Interval(0, headerEnd);
-
-  Interval get footer => new Interval(footerStart, lines.length);
-
-  /// Compute the structure of the JavaScript [lines].
-  static OutputStructure parse(List<CodeLine> lines) {
-
-    int findHeaderStart(List<CodeLine> lines) {
-      int index = 0;
-      for (CodeLine line in lines) {
-        if (line.code.startsWith(HEAD)) {
-          return index;
-        }
-        index++;
-      }
-      return lines.length;
-    }
-
-    int findHeaderEnd(int start, List<CodeLine> lines) {
-      int index = start;
-      for (CodeLine line in lines.skip(start)) {
-        if (line.code.startsWith(END)) {
-          return index;
-        }
-        index++;
-      }
-      return lines.length;
-    }
-
-    String readHeader(CodeLine line) {
-      String code = line.code;
-      String ssaLineHeader;
-      if (code.startsWith(HEAD)) {
-        return code.substring(HEAD.length);
-      } else if (code.startsWith(TAIL)) {
-        return code.substring(TAIL.length);
-      }
-      return null;
-    }
-
-    List<LibraryBlock> computeHeaderMap(
-        List<CodeLine> lines, int start, int end) {
-      List<LibraryBlock> libraryBlocks = <LibraryBlock>[];
-      LibraryBlock current;
-      for (int index = start; index < end; index++) {
-        String header = readHeader(lines[index]);
-        if (header != null) {
-          if (current != null) {
-            current.to = index;
-          }
-          libraryBlocks.add(current = new LibraryBlock(header, index));
-        }
-      }
-      if (current != null) {
-        current.to = end;
-      }
-      return libraryBlocks;
-    }
-
-    int headerEnd = findHeaderStart(lines);
-    int footerStart = findHeaderEnd(headerEnd, lines);
-    List<LibraryBlock> libraryBlocks =
-        computeHeaderMap(lines, headerEnd, footerStart);
-    for (LibraryBlock block in libraryBlocks) {
-      block.preprocess(lines);
-    }
-
-    return new OutputStructure(
-        lines, headerEnd, footerStart, libraryBlocks);
-  }
-}
-
-abstract class AbstractEntity extends OutputEntity {
-  final String name;
-  final int from;
-  int to;
-
-  AbstractEntity(this.name, this.from);
-
-  Interval get interval => new Interval(from, to);
-}
-
-/// A block defining the content of a Dart library.
-class LibraryBlock extends AbstractEntity {
-  List<BasicEntity> children = <BasicEntity>[];
-  int get headerEnd => from + 2;
-  int get footerStart => to - 1;
-
-  LibraryBlock(String name, int from) : super(name, from);
-
-  Interval get header => new Interval(from, headerEnd);
-
-  Interval get footer => new Interval(footerStart, to);
-
-  void preprocess(List<CodeLine> lines) {
-    int index = headerEnd;
-    BasicEntity current;
-    while (index < footerStart) {
-      String line = lines[index].code;
-      BasicEntity next;
-      Match matchFunction = TOP_LEVEL_FUNCTION.firstMatch(line);
-      if (matchFunction != null) {
-        next = new BasicEntity(matchFunction.group(1), index);
-      } else {
-        Match matchClass = TOP_LEVEL_CLASS.firstMatch(line);
-        if (matchClass != null) {
-          next = new LibraryClass(matchClass.group(1), index);
-        } else {
-          Match matchValue = TOP_LEVEL_VALUE.firstMatch(line);
-          if (matchValue != null) {
-            next = new BasicEntity(matchValue.group(1), index);
-          }
-        }
-      }
-      if (next != null) {
-        if (current != null) {
-          current.to = index;
-        }
-        children.add(current = next);
-      } else if (index == headerEnd) {
-        throw 'Failed to match first library block line:\n$line';
-      }
-
-      index++;
-    }
-    if (current != null) {
-      current.to = footerStart;
-    }
-
-    for (BasicEntity entity in children) {
-      entity.preprocess(lines);
-    }
-  }
-}
-
-/// A simple member of a library or class.
-class BasicEntity extends AbstractEntity {
-  BasicEntity(String name, int from) : super(name, from);
-
-  Interval get header => new Interval(from, to);
-
-  Interval get footer => new Interval(to, to);
-
-  List<OutputEntity> get children => const <OutputEntity>[];
-
-  void preprocess(List<CodeLine> lines) {}
-}
-
-/// A block defining a Dart class.
-class LibraryClass extends BasicEntity {
-  List<BasicEntity> children = <BasicEntity>[];
-  int get headerEnd => from + 1;
-  int get footerStart => to - 1;
-
-  LibraryClass(String name, int from) : super(name, from);
-
-  Interval get header => new Interval(from, headerEnd);
-
-  Interval get footer => new Interval(footerStart, to);
-
-  void preprocess(List<CodeLine> lines) {
-    int index = headerEnd;
-    BasicEntity current;
-    while (index < footerStart) {
-      String line = lines[index].code;
-      BasicEntity next;
-      Match matchFunction = MEMBER_FUNCTION.firstMatch(line);
-      if (matchFunction != null) {
-        next = new BasicEntity(matchFunction.group(1), index);
-      } else {
-        Match matchClass = MEMBER_OBJECT.firstMatch(line);
-        if (matchClass != null) {
-          next = new BasicEntity(matchClass.group(1), index);
-        } else {
-          Match matchValue = MEMBER_VALUE.firstMatch(line);
-          if (matchValue != null) {
-            next = new BasicEntity(matchValue.group(1), index);
-          }
-        }
-      }
-      if (next != null) {
-        if (current != null) {
-          current.to = index;
-        }
-        children.add(current = next);
-      } else if (index == headerEnd) {
-        throw 'Failed to match first library block line:\n$line';
-      }
-
-      index++;
-    }
-    if (current != null) {
-      current.to = footerStart;
-    }
-  }
-}
-
-class Interval {
-  final int from;
-  final int to;
-
-  const Interval(this.from, this.to);
-
-  int get length => to - from;
-}
-
-class HtmlPart {
-  void printHtmlOn(StringBuffer buffer) {}
-}
-
-class ConstHtmlPart implements HtmlPart {
-  final String html;
-
-  const ConstHtmlPart(this.html);
-
-  @override
-  void printHtmlOn(StringBuffer buffer) {
-    buffer.write(html);
-  }
-}
-
-class CodeLineHtmlPart implements HtmlPart {
-  final CodeLine line;
-
-  CodeLineHtmlPart(this.line);
-
-  @override
-  void printHtmlOn(StringBuffer buffer, [int lineNoWidth]) {
-    line.printHtmlOn(buffer, lineNoWidth);
-  }
-}
-
-/// Convert [parts] to an HTML string while checking invariants for [lines].
-String htmlPartsToString(List<HtmlPart> parts, List<CodeLine> lines) {
-  int lineNoWidth;
-  if (lines.isNotEmpty) {
-    lineNoWidth = '${lines.last.lineNo + 1}'.length;
-  }
-  StringBuffer buffer = new StringBuffer();
-  int expectedLineNo = 0;
-  for (HtmlPart part in parts) {
-    if (part is CodeLineHtmlPart) {
-      if (part.line.lineNo != expectedLineNo) {
-        print('Expected line no $expectedLineNo, found ${part.line.lineNo}');
-        if (part.line.lineNo < expectedLineNo) {
-          print('Duplicate lines:');
-          int index = part.line.lineNo;
-          while (index <= expectedLineNo) {
-            print(lines[index++].code);
-          }
-        } else {
-          print('Missing lines:');
-          int index = expectedLineNo;
-          while (index <= part.line.lineNo) {
-            print(lines[index++].code);
-          }
-        }
-        expectedLineNo = part.line.lineNo;
-      }
-      expectedLineNo++;
-      part.printHtmlOn(buffer, lineNoWidth);
-    } else {
-      part.printHtmlOn(buffer);
-    }
-  }
-  return buffer.toString();
-}
-
 class CodeLinesResult {
   final List<CodeLine> codeLines;
   final Coverage coverage;
+  final Map<int, Element> elementMap;
+  final SourceFileManager sourceFileManager;
 
-  CodeLinesResult(this.codeLines, this.coverage);
+  CodeLinesResult(this.codeLines, this.coverage,
+      this.elementMap, this.sourceFileManager);
 }
 
 /// Compute [CodeLine]s and [Coverage] for [filename] using the given [options].
 Future<CodeLinesResult> computeCodeLines(
     List<String> options,
     String filename,
     {bool addAnnotations: true}) async {
   SourceMapProcessor processor = new SourceMapProcessor(filename);
-  List<SourceMapInfo> sourceMapInfoList =
-      await processor.process(options, perElement: false);
+  SourceMaps sourceMaps =
+      await processor.process(options, perElement: true, forMain: true);
 
   const int WITH_SOURCE_INFO = 0;
   const int WITHOUT_SOURCE_INFO = 1;
   const int ADDITIONAL_SOURCE_INFO = 2;
+  const int UNUSED_SOURCE_INFO = 3;
 
-  for (SourceMapInfo info in sourceMapInfoList) {
-    if (info.element != null) continue;
+  SourceMapInfo info = sourceMaps.mainSourceMapInfo;
 
-    List<CodeLine> codeLines;
-    Coverage coverage = new Coverage();
-    List<Annotation> annotations = <Annotation>[];
+  List<CodeLine> codeLines;
+  Coverage coverage = new Coverage();
+  List<Annotation> annotations = <Annotation>[];
 
-    String code = info.code;
-    TraceGraph graph = createTraceGraph(info, coverage);
-    if (addAnnotations) {
-      Set<js.Node> mappedNodes = new Set<js.Node>();
-      for (TraceStep step in graph.steps) {
+  void addAnnotation(int id, int offset, String title) {
+    annotations.add(new Annotation(id, offset, title));
+  }
+
+  String code = info.code;
+  TraceGraph graph = createTraceGraph(info, coverage);
+  if (addAnnotations) {
+    Set<js.Node> mappedNodes = new Set<js.Node>();
+
+    void addSourceLocations(
+        int kind, int offset, List<SourceLocation> locations, String prefix) {
+
+      addAnnotation(kind, offset,
+          '${prefix}${locations
+              .where((l) => l != null)
+              .map((l) => l.shortText)
+              .join('\n')}');
+    }
+
+    bool addSourceLocationsForNode(int kind, js.Node node, String prefix) {
+      Map<int, List<SourceLocation>> locations = info.nodeMap[node];
+      if (locations == null || locations.isEmpty) {
+        return false;
+      }
+      locations.forEach(
+          (int offset, List<SourceLocation> locations) {
+        addSourceLocations(kind, offset, locations,
+            '${prefix}\n${truncate(nodeToString(node), 80)}\n');
+      });
+      mappedNodes.add(node);
+      return true;
+    }
+
+
+    for (TraceStep step in graph.steps) {
+      String title = '${step.id}:${step.kind}:${step.offset}';
+      if (!addSourceLocationsForNode(WITH_SOURCE_INFO, step.node, title)) {
         int offset;
         if (options.contains(USE_NEW_SOURCE_INFO)) {
           offset = step.offset.subexpressionOffset;
         } else {
           offset = info.jsCodePositions[step.node].startPosition;
         }
         if (offset != null) {
-          int id = step.sourceLocation != null
-              ? WITH_SOURCE_INFO : WITHOUT_SOURCE_INFO;
-          annotations.add(
-              new Annotation(id, offset, null));
-        }
-      }
-      if (!options.contains(USE_NEW_SOURCE_INFO)) {
-        for (js.Node node in info.nodeMap.nodes) {
-          if (!mappedNodes.contains(node)) {
-            int offset = info.jsCodePositions[node].startPosition;
-            annotations.add(
-                        new Annotation(ADDITIONAL_SOURCE_INFO, offset, null));
-          }
+          addAnnotation(WITHOUT_SOURCE_INFO, offset, title);
         }
       }
     }
-    codeLines = convertAnnotatedCodeToCodeLines(
-        code,
-        annotations,
-        colorScheme: new CustomColorScheme(
-          single: (int id) {
-            if (id == WITH_SOURCE_INFO) {
-              return WITH_SOURCE_INFO_STYLE;
-            } else if (id == ADDITIONAL_SOURCE_INFO) {
-              return ADDITIONAL_SOURCE_INFO_STYLE;
-            }
-            return WITHOUT_SOURCE_INFO_STYLE;
-          },
-          multi: (List ids) {
-            if (ids.contains(WITH_SOURCE_INFO)) {
-              return WITH_SOURCE_INFO_STYLE;
-            } else if (ids.contains(ADDITIONAL_SOURCE_INFO)) {
-              return ADDITIONAL_SOURCE_INFO_STYLE;
-            }
-            return WITHOUT_SOURCE_INFO_STYLE;
+    for (js.Node node in info.nodeMap.nodes) {
+      if (!mappedNodes.contains(node)) {
+        addSourceLocationsForNode(ADDITIONAL_SOURCE_INFO, node, '');
+      }
+    }
+    SourceLocationCollector collector = new SourceLocationCollector();
+    info.node.accept(collector);
+    collector.sourceLocations.forEach(
+        (js.Node node, List<SourceLocation> locations) {
+      if (!mappedNodes.contains(node)) {
+        int offset = info.jsCodePositions[node].startPosition;
+        addSourceLocations(UNUSED_SOURCE_INFO, offset, locations, '');
+      }
+    });
+  }
+
+  StringSourceFile sourceFile = new StringSourceFile.fromName(filename, code);
+  Map<int, Element> elementMap = <int, Element>{};
+  sourceMaps.elementSourceMapInfos.forEach(
+      (Element element, SourceMapInfo info) {
+    CodePosition position = info.jsCodePositions[info.node];
+    elementMap[sourceFile.getLine(position.startPosition)] = element;
+  });
+
+  codeLines = convertAnnotatedCodeToCodeLines(
+      code,
+      annotations,
+      colorScheme: new CustomColorScheme(
+        single: (int id) {
+          if (id == WITH_SOURCE_INFO) {
+            return WITH_SOURCE_INFO_STYLE;
+          } else if (id == ADDITIONAL_SOURCE_INFO) {
+            return ADDITIONAL_SOURCE_INFO_STYLE;
+          } else if (id == UNUSED_SOURCE_INFO) {
+            return UNUSED_SOURCE_INFO_STYLE;
           }
-        ));
-    return new CodeLinesResult(codeLines, coverage);
+          return WITHOUT_SOURCE_INFO_STYLE;
+        },
+        multi: (List ids) {
+          if (ids.contains(WITH_SOURCE_INFO)) {
+            return WITH_SOURCE_INFO_STYLE;
+          } else if (ids.contains(ADDITIONAL_SOURCE_INFO)) {
+            return ADDITIONAL_SOURCE_INFO_STYLE;
+          } else if (ids.contains(UNUSED_SOURCE_INFO)) {
+            return UNUSED_SOURCE_INFO_STYLE;
+          }
+          return WITHOUT_SOURCE_INFO_STYLE;
+        }
+      ));
+  return new CodeLinesResult(codeLines, coverage, elementMap,
+      sourceMaps.sourceFileManager);
+}
+
+/// Visitor that computes a map from [js.Node]s to all attached source
+/// locations.
+class SourceLocationCollector extends js.BaseVisitor {
+  Map<js.Node, List<SourceLocation>> sourceLocations =
+      <js.Node, List<SourceLocation>>{};
+
+  @override
+  visitNode(js.Node node) {
+    SourceInformation sourceInformation = node.sourceInformation;
+    if (sourceInformation != null) {
+      sourceLocations[node] = sourceInformation.sourceLocations;
+    }
+    node.visitChildren(this);
   }
 }
+
+/// Compute a [CodeSource] for source span of [element].
+CodeSource codeSourceFromElement(Element element) {
+  CodeKind kind;
+  Uri uri;
+  String name;
+  int begin;
+  int end;
+  if (element.isLibrary) {
+    LibraryElement library = element;
+    kind = CodeKind.LIBRARY;
+    name = library.libraryOrScriptName;
+    uri = library.entryCompilationUnit.script.resourceUri;
+  } else if (element.isClass) {
+    kind = CodeKind.CLASS;
+    name = element.name;
+    uri = element.compilationUnit.script.resourceUri;
+  } else {
+    AstElement astElement = element.implementation;
+    kind = CodeKind.MEMBER;
+    uri = astElement.compilationUnit.script.resourceUri;
+    name = computeElementNameForSourceMaps(astElement);
+    if (astElement.hasNode) {
+      begin = astElement.node.getBeginToken().charOffset;
+      end = astElement.node.getEndToken().charEnd;
+    }
+  }
+  return new CodeSource(kind, uri, name, begin, end);
+}