Base JavaScript code position computation on JavaScript tracer.

tests/compiler/dart2js/sourcemaps/sourcemap_helper.dart

Index: tests/compiler/dart2js/sourcemaps/sourcemap_helper.dart
diff --git a/tests/compiler/dart2js/sourcemaps/sourcemap_helper.dart b/tests/compiler/dart2js/sourcemaps/sourcemap_helper.dart
index 9cb53e566d977cf1e567ef943f6dc7ee9507ba74..123cbe2a918ac1e427c2b116d9d8a5ad7422ab7a 100644
--- a/tests/compiler/dart2js/sourcemaps/sourcemap_helper.dart
+++ b/tests/compiler/dart2js/sourcemaps/sourcemap_helper.dart
@@ -11,8 +11,10 @@ import 'package:compiler/src/null_compiler_output.dart' show NullSink;
 import 'package:compiler/src/elements/elements.dart';
 import 'package:compiler/src/helpers/helpers.dart';
 import 'package:compiler/src/filenames.dart';
+import 'package:compiler/src/io/code_output.dart';
 import 'package:compiler/src/io/source_file.dart';
 import 'package:compiler/src/io/source_information.dart';
+import 'package:compiler/src/io/position_information.dart';
 import 'package:compiler/src/js/js.dart' as js;
 import 'package:compiler/src/js/js_debug.dart';
 import 'package:compiler/src/js/js_source_mapping.dart';
@@ -21,15 +23,51 @@ import 'package:compiler/src/source_file_provider.dart';
 import '../memory_compiler.dart';
 import '../output_collector.dart';
 
+class SourceFileSink implements EventSink<String> {
+  final String filename;
+  StringBuffer sb = new StringBuffer();
+  SourceFile sourceFile;
+
+  SourceFileSink(this.filename);
+
+  @override
+  void add(String event) {
+    sb.write(event);
+  }
+
+  @override
+  void addError(errorEvent, [StackTrace stackTrace]) {
+    // Ignore.
+  }
+
+  @override
+  void close() {
+    sourceFile = new StringSourceFile.fromName(filename, sb.toString());
+  }
+}
+
 class OutputProvider implements CompilerOutput {
-  BufferedEventSink jsMapOutput;
+  Map<Uri, SourceFileSink> outputMap = <Uri, SourceFileSink>{};
+
+  SourceFile getSourceFile(Uri uri) {
+    SourceFileSink sink = outputMap[uri];
+    if (sink != null) {
+      return sink.sourceFile;
+    }
+    return null;
+  }
+
+  SourceFileSink createSourceFileSink(String name, String extension) {
+    String filename = '$name.$extension';
+    SourceFileSink sink = new SourceFileSink(filename);
+    Uri uri = Uri.parse(filename);
+    outputMap[uri] = sink;
+    return sink;
+  }
 
   @override
   EventSink<String> createEventSink(String name, String extension) {
-    if (extension == 'js.map') {
-      return jsMapOutput = new BufferedEventSink();
-    }
-    return new NullSink('$name.$extension');
+    return createSourceFileSink(name, extension);
   }
 }
 
@@ -42,11 +80,8 @@ class CloningOutputProvider extends OutputProvider {
   @override
   EventSink<String> createEventSink(String name, String extension) {
     EventSink<String> output = outputProvider(name, extension);
-    if (extension == 'js.map') {
-      output = new CloningEventSink(
-          [output, jsMapOutput = new BufferedEventSink()]);
-    }
-    return output;
+    return new CloningEventSink(
+        [output, createSourceFileSink(name, extension)]);
   }
 }
 
@@ -56,17 +91,23 @@ abstract class SourceFileManager {
 
 class ProviderSourceFileManager implements SourceFileManager {
   final SourceFileProvider sourceFileProvider;
+  final OutputProvider outputProvider;
 
-  ProviderSourceFileManager(this.sourceFileProvider);
+  ProviderSourceFileManager(this.sourceFileProvider, this.outputProvider);
 
   @override
   SourceFile getSourceFile(uri) {
-    return sourceFileProvider.getSourceFile(uri);
+    SourceFile sourceFile = sourceFileProvider.getSourceFile(uri);
+    if (sourceFile == null) {
+      sourceFile = outputProvider.getSourceFile(uri);
+    }
+    return sourceFile;
   }
 }
 
 class RecordingPrintingContext extends LenientPrintingContext {
   CodePositionListener listener;
+  Map<js.Node, CodePosition> codePositions = <js.Node, CodePosition>{};
 
   RecordingPrintingContext(this.listener);
 
@@ -75,11 +116,163 @@ class RecordingPrintingContext extends LenientPrintingContext {
                 int startPosition,
                 int endPosition,
                 int closingPosition) {
+    codePositions[node] =
+        new CodePosition(startPosition, endPosition, closingPosition);
     listener.onPositions(
         node, startPosition, endPosition, closingPosition);
   }
 }
 
+/// A [SourceMapper] that records the source locations on each node.
+class RecordingSourceMapper implements SourceMapper {
+  final SourceMapper sourceMapper;
+  final _LocationRecorder nodeToSourceLocationsMap;
+
+  RecordingSourceMapper(this.sourceMapper, this.nodeToSourceLocationsMap);
+
+  @override
+  void register(js.Node node, int codeOffset, SourceLocation sourceLocation) {
+    nodeToSourceLocationsMap.register(node, codeOffset, sourceLocation);
+    sourceMapper.register(node, codeOffset, sourceLocation);
+  }
+}
+
+/// A wrapper of [SourceInformationProcessor] that records source locations and
+/// code positions.
+class RecordingSourceInformationProcessor
+    implements SourceInformationProcessor {
+  final RecordingSourceInformationStrategy wrapper;
+  final SourceInformationProcessor processor;
+  final CodePositionRecorder codePositions;
+  final LocationMap nodeToSourceLocationsMap;
+
+  RecordingSourceInformationProcessor(
+      this.wrapper,
+      this.processor,
+      this.codePositions,
+      this.nodeToSourceLocationsMap);
+
+  @override
+  void onPositions(js.Node node,
+                   int startPosition,
+                   int endPosition,
+                   int closingPosition) {
+    codePositions.registerPositions(
+        node, startPosition, endPosition, closingPosition);
+    processor.onPositions(node, startPosition, endPosition, closingPosition);
+  }
+
+  @override
+  void process(js.Node node, BufferedCodeOutput code) {
+    processor.process(node, code);
+    wrapper.registerProcess(
+        node, code, codePositions, nodeToSourceLocationsMap);
+  }
+}
+
+/// Information recording for a use of [SourceInformationProcessor].
+class RecordedSourceInformationProcess {
+  final js.Node root;
+  final String code;
+  final CodePositionRecorder codePositions;
+  final LocationMap nodeToSourceLocationsMap;
+
+  RecordedSourceInformationProcess(
+      this.root,
+      this.code,
+      this.codePositions,
+      this.nodeToSourceLocationsMap);
+}
+
+
+/// A wrapper of [JavaScriptSourceInformationStrategy] that records
+/// [RecordedSourceInformationProcess].
+class RecordingSourceInformationStrategy
+    extends JavaScriptSourceInformationStrategy {
+  final JavaScriptSourceInformationStrategy strategy;
+  final Map<RecordedSourceInformationProcess, js.Node> processMap =
+      <RecordedSourceInformationProcess, js.Node>{};
+  final Map<js.Node, RecordedSourceInformationProcess> nodeMap =
+      <js.Node, RecordedSourceInformationProcess>{};
+
+  RecordingSourceInformationStrategy(this.strategy);
+
+  @override
+  SourceInformationBuilder createBuilderForContext(AstElement element) {
+    return strategy.createBuilderForContext(element);
+  }
+
+  @override
+  SourceInformationProcessor createProcessor(SourceMapper sourceMapper) {
+    LocationMap nodeToSourceLocationsMap =
+        new _LocationRecorder();
+    CodePositionRecorder codePositions = new CodePositionRecorder();
+    return new RecordingSourceInformationProcessor(
+        this,
+        strategy.createProcessor(new RecordingSourceMapper(
+            sourceMapper, nodeToSourceLocationsMap)),
+            codePositions, nodeToSourceLocationsMap);
+  }
+
+  void registerProcess(js.Node root,
+                       BufferedCodeOutput code,
+                       CodePositionRecorder codePositions,
+                       LocationMap nodeToSourceLocationsMap) {
+    RecordedSourceInformationProcess subProcess =
+        new RecordedSourceInformationProcess(
+            root, code.getText(), codePositions, nodeToSourceLocationsMap);
+    processMap[subProcess] = root;
+  }
+
+  RecordedSourceInformationProcess subProcessForNode(js.Node node) {
+    return nodeMap.putIfAbsent(node, () {
+      for (RecordedSourceInformationProcess subProcess in processMap.keys) {
+        js.Node root = processMap[subProcess];
+        FindVisitor visitor = new FindVisitor(node);
+        root.accept(visitor);
+        if (visitor.found) {
+          return new RecordedSourceInformationProcess(
+              node,
+              subProcess.code,
+              subProcess.codePositions,
+              new _FilteredLocationMap(
+                  visitor.nodes, subProcess.nodeToSourceLocationsMap));
+        }
+        return null;
+      }
+    });
+  }
+}
+
+/// Visitor that collects all nodes that are within a function. Used by the
+/// [RecordingSourceInformationStrategy] to filter what is recorded in a
+/// [RecordedSourceInformationProcess].
+class FindVisitor extends js.BaseVisitor {
+  final js.Node soughtNode;
+  bool found = false;
+  bool add = false;
+  final Set<js.Node> nodes = new Set<js.Node>();
+
+  FindVisitor(this.soughtNode);
+
+  visitNode(js.Node node) {
+    if (node == soughtNode) {
+      found = true;
+      add = true;
+    }
+    if (add) {
+      nodes.add(node);
+    }
+    node.visitChildren(this);
+    if (node == soughtNode) {
+      add = false;
+    }
+  }
+}
+
+const String USE_NEW_SOURCE_INFO =  '--use-new-source-info';
+const String DISABLE_INLINING = '--disable-inlining';
+
 /// Processor that computes [SourceMapInfo] for the JavaScript compiled for a
 /// given Dart file.
 class SourceMapProcessor {
@@ -112,11 +305,12 @@ class SourceMapProcessor {
   /// Computes the [SourceMapInfo] for the compiled elements.
   Future<List<SourceMapInfo>> process(
       List<String> options,
-      {bool verbose: true}) async {
+      {bool verbose: true,
+       bool perElement: true}) async {
     OutputProvider outputProvider = outputToFile
-        ? new OutputProvider()
-        : new CloningOutputProvider(targetUri, sourceMapFileUri);
-    if (options.contains('--use-new-source-info')) {
+        ? new CloningOutputProvider(targetUri, sourceMapFileUri)
+        : new OutputProvider();
+    if (options.contains(USE_NEW_SOURCE_INFO)) {
       if (verbose) print('Using the new source information system.');
       useNewSourceInfo = true;
     }
@@ -125,7 +319,7 @@ class SourceMapProcessor {
         // TODO(johnniwinther): Use [verbose] to avoid showing diagnostics.
         options: ['--out=$targetUri', '--source-map=$sourceMapFileUri']
             ..addAll(options));
-    if (options.contains('--disable-inlining')) {
+    if (options.contains(DISABLE_INLINING)) {
       if (verbose) print('Inlining disabled');
       compiler.disableInlining = true;
     }
@@ -133,30 +327,58 @@ class SourceMapProcessor {
     JavaScriptBackend backend = compiler.backend;
     var handler = compiler.handler;
     SourceFileProvider sourceFileProvider = handler.provider;
-    sourceFileManager = new ProviderSourceFileManager(sourceFileProvider);
+    sourceFileManager = new ProviderSourceFileManager(
+        sourceFileProvider,
+        outputProvider);
+    RecordingSourceInformationStrategy strategy =
+        new RecordingSourceInformationStrategy(backend.sourceInformationStrategy);
+    backend.sourceInformationStrategy = strategy;
     await compiler.run(inputUri);
 
     List<SourceMapInfo> infoList = <SourceMapInfo>[];
-    backend.generatedCode.forEach((Element element, js.Expression node) {
-      js.JavaScriptPrintingOptions options =
-          new js.JavaScriptPrintingOptions();
-      JavaScriptSourceInformationStrategy sourceInformationStrategy =
-          compiler.backend.sourceInformationStrategy;
-      NodeToSourceLocationsMap nodeMap = new NodeToSourceLocationsMap();
-      SourceInformationProcessor sourceInformationProcessor =
-          sourceInformationStrategy.createProcessor(nodeMap);
-      RecordingPrintingContext printingContext =
-          new RecordingPrintingContext(sourceInformationProcessor);
-      new js.Printer(options, printingContext).visit(node);
-      sourceInformationProcessor.process(node);
-
-      String code = printingContext.getText();
+    if (perElement) {
+      backend.generatedCode.forEach((Element element, js.Expression node) {
+        RecordedSourceInformationProcess subProcess =
+            strategy.subProcessForNode(node);
+        if (subProcess == null) {
+          // TODO(johnniwinther): Find out when this is happening and if it
+          // is benign. (Known to happen for `bool#fromString`)
+          print('No subProcess found for $element');
+          return;
+        }
+        LocationMap nodeMap = subProcess.nodeToSourceLocationsMap;
+        String code = subProcess.code;
+        CodePositionRecorder codePositions = subProcess.codePositions;
+        CodePointComputer visitor =
+            new CodePointComputer(sourceFileManager, code, nodeMap);
+        visitor.apply(node);
+        List<CodePoint> codePoints = visitor.codePoints;
+        infoList.add(new SourceMapInfo(
+            element, code, node,
+            codePoints,
+            codePositions/*strategy.codePositions*/,
+            nodeMap));
+      });
+    } else {
+      // TODO(johnniwinther): Supported multiple output units.
+      RecordedSourceInformationProcess process = strategy.processMap.keys.first;
+      js.Node node = strategy.processMap[process];
+      String code;
+      LocationMap nodeMap;
+      CodePositionRecorder codePositions;
+      nodeMap = process.nodeToSourceLocationsMap;
+      code = process.code;
+      codePositions = process.codePositions;
       CodePointComputer visitor =
           new CodePointComputer(sourceFileManager, code, nodeMap);
       visitor.apply(node);
       List<CodePoint> codePoints = visitor.codePoints;
-      infoList.add(new SourceMapInfo(element, code, node, codePoints, nodeMap));
-    });
+      infoList.add(new SourceMapInfo(
+          null, code, node,
+          codePoints,
+          codePositions,
+          nodeMap));
+    }
 
     return infoList;
   }
@@ -167,19 +389,43 @@ class SourceMapInfo {
   final String name;
   final Element element;
   final String code;
-  final js.Expression node;
+  final js.Node node;
   final List<CodePoint> codePoints;
-  final NodeToSourceLocationsMap nodeMap;
+  final CodePositionMap jsCodePositions;
+  final LocationMap nodeMap;
 
   SourceMapInfo(
-      Element element, this.code, this.node, this.codePoints, this.nodeMap)
-      : this.name = computeElementNameForSourceMaps(element),
+      Element element,
+      this.code,
+      this.node,
+      this.codePoints,
+      this.jsCodePositions,
+      this.nodeMap)
+      : this.name =
+          element != null ? computeElementNameForSourceMaps(element) : '',
         this.element = element;
+
+  String toString() {
+    return '$name:$element';
+  }
 }
 
 /// Collection of JavaScript nodes with their source mapped target offsets
 /// and source locations.
-class NodeToSourceLocationsMap implements SourceMapper {
+abstract class LocationMap {
+  Iterable<js.Node> get nodes;
+
+  Map<int, List<SourceLocation>> operator[] (js.Node node);
+
+  factory LocationMap.recorder() = _LocationRecorder;
+
+  factory LocationMap.filter(Set<js.Node> nodes, LocationMap map) =
+      _FilteredLocationMap;
+
+}
+
+class _LocationRecorder
+    implements SourceMapper, LocationMap {
   final Map<js.Node, Map<int, List<SourceLocation>>> _nodeMap = {};
 
   @override
@@ -196,11 +442,25 @@ class NodeToSourceLocationsMap implements SourceMapper {
   }
 }
 
+class _FilteredLocationMap implements LocationMap {
+  final Set<js.Node> _nodes;
+  final LocationMap map;
+
+  _FilteredLocationMap(this._nodes, this.map);
+
+  Iterable<js.Node> get nodes => map.nodes.where((n) => _nodes.contains(n));
+
+  Map<int, List<SourceLocation>> operator[] (js.Node node) {
+    return map[node];
+  }
+}
+
+
 /// Visitor that computes the [CodePoint]s for source mapping locations.
 class CodePointComputer extends js.BaseVisitor {
   final SourceFileManager sourceFileManager;
   final String code;
-  final NodeToSourceLocationsMap nodeMap;
+  final LocationMap nodeMap;
   List<CodePoint> codePoints = [];
 
   CodePointComputer(this.sourceFileManager, this.code, this.nodeMap);