pkg/compiler/lib/src/inferrer/type_graph_dump.dart - sdk.git - Git at Google

 // 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 dart2js.inferrer.type_graph_dump;

 import '../../compiler_new.dart';
 import '../elements/entities.dart';
 import '../elements/entity_utils.dart' as utils;
 import '../types/abstract_value_domain.dart';
 import 'inferrer_engine.dart';
 import 'type_graph_nodes.dart';
 import 'debug.dart';

 /// Dumps the type inference graph in Graphviz Dot format into the `typegraph`
 /// subfolder of the current working directory. Each function body is dumped in
 /// a separate file.
 ///
 /// The resulting .dot files must be processed using the Graphviz `dot` command,
 /// which can be obtained from `http://www.graphviz.org`, or installed using
 /// most package managers (search for `graphviz` or `dot`).
 ///
 /// Example commands:
 ///
 ///     dot -Tpng -O typegraph/main.dot
 ///     open typegraph/main.dot.png
 ///
 ///     dot -Tpng -O typegraph/dart._internal.Sort._dualPivotQuicksort.dot
 ///     open typegraph/dart._internal.Sort._dualPivotQuicksort.dot.png
 ///
 class TypeGraphDump {
   static const String outputDir = 'typegraph';

   final CompilerOutput compilerOutput;
   final InferrerEngine inferrer;
   final Map<TypeInformation, Set<TypeInformation>> assignmentsBeforeAnalysis =
       <TypeInformation, Set<TypeInformation>>{};
   final Map<TypeInformation, Set<TypeInformation>> assignmentsBeforeTracing =
       <TypeInformation, Set<TypeInformation>>{};
   final Set<String> usedFilenames = new Set<String>();

   TypeGraphDump(this.compilerOutput, this.inferrer);

   /// Take a copy of the assignment set for each node, since that may change
   /// during the analysis.
   void beforeAnalysis() {
     for (TypeInformation node in inferrer.types.allTypes) {
       Set<TypeInformation> copy = node.assignments.toSet();
       if (!copy.isEmpty) {
         assignmentsBeforeAnalysis[node] = copy;
       }
     }
   }

   /// Like [beforeAnalysis], takes a copy of the assignment sets.
   void beforeTracing() {
     for (TypeInformation node in inferrer.types.allTypes) {
       Set<TypeInformation> copy = node.assignments.toSet();
       if (!copy.isEmpty) {
         assignmentsBeforeTracing[node] = copy;
       }
     }
   }

   /// Dumps the entire graph.
   void afterAnalysis() {
     // Group all the type nodes by their context member.
     Map<MemberEntity, List<TypeInformation>> nodes =
         <MemberEntity, List<TypeInformation>>{};
     for (TypeInformation node in inferrer.types.allTypes) {
       if (node.contextMember != null) {
         nodes
             .putIfAbsent(node.contextMember, () => <TypeInformation>[])
             .add(node);
       }
     }
     // Print every group separately.
     for (MemberEntity element in nodes.keys) {
       OutputSink output;
       try {
         String name = filenameFromElement(element);
         output = compilerOutput.createOutputSink(
             '$outputDir/$name', 'dot', OutputType.debug);
         _GraphGenerator visitor = new _GraphGenerator(
             this, element, output, inferrer.abstractValueDomain.getCompactText);
         for (TypeInformation node in nodes[element]) {
           visitor.visit(node);
         }
         visitor.addMissingNodes();
         visitor.finish();
       } finally {
         if (output != null) {
           output.close();
         }
       }
     }
   }

   /// Returns the filename (without extension) in which to dump the type
   /// graph for [element].
   ///
   /// Will never return the a given filename more than once, even if called with
   /// the same element.
   String filenameFromElement(MemberEntity element) {
     // The toString method of elements include characters that are unsuitable
     // for URIs and file systems.
     List<String> parts = <String>[];
     parts.add(element.library.canonicalUri.pathSegments.last);
     parts.add(element.enclosingClass?.name);
     if (element.isGetter) {
       parts.add('get-${element.name}');
     } else if (element.isSetter) {
       parts.add('set-${element.name}');
     } else if (element.isConstructor) {
       if (element.name.isEmpty) {
         parts.add('-constructor');
       } else {
         parts.add(element.name);
       }
     } else {
       parts.add(
           utils.operatorNameToIdentifier(element.name).replaceAll(r'$', '-'));
     }
     String filename = parts.where((x) => x != null && x != '').join('.');
     if (usedFilenames.add(filename)) return filename;
     // The filename has already been used by another method. Append a serial
     // number to ensure we don't overwrite it.
     int serialNumber = 2;
     while (!usedFilenames.add('$filename-$serialNumber')) {
       ++serialNumber;
     }
     return '$filename-$serialNumber';
   }
 }

 /// Builds the Graphviz Dot file for one function body.
 class _GraphGenerator extends TypeInformationVisitor {
   final TypeGraphDump global;
   final Set<TypeInformation> seen = new Set<TypeInformation>();
   final List<TypeInformation> worklist = new List<TypeInformation>();
   final Map<TypeInformation, int> nodeId = <TypeInformation, int>{};
   final String Function(AbstractValue) formatType;
   int usedIds = 0;
   final OutputSink output;
   final MemberEntity element;
   TypeInformation returnValue;

   _GraphGenerator(this.global, this.element, this.output, this.formatType) {
     returnValue = global.inferrer.types.getInferredTypeOfMember(element);
     getNode(returnValue); // Ensure return value is part of graph.
     append('digraph {');
   }

   void finish() {
     append('}');
   }

   /// Ensures that all nodes which have been referenced are generated.
   ///
   /// Sometimes an input to a TypeInformation node does not belong to the same
   /// function body, and the graph looks confusing if they are missing.
   void addMissingNodes() {
     while (worklist.isNotEmpty) {
       TypeInformation node = worklist.removeLast();
       assert(nodeId.containsKey(node));
       visit(node);
     }
   }

   void visit(TypeInformation info) {
     if (seen.contains(info)) return;
     info.accept(this);
   }

   void append(String string) {
     output..add(string)..add('\n');
   }

   String shorten(String text) {
     if (text.length > 40) {
       return text.substring(0, 19) + '...' + text.substring(text.length - 18);
     }
     return text;
   }

   int getFreshId() => ++usedIds;

   /// Obtains a unique ID for the node representing [info].
   String getNode(TypeInformation info) {
     int id = nodeId.putIfAbsent(info, () {
       worklist.add(info); // Ensure that the referenced node is generated.
       return getFreshId();
     });
     return '$id';
   }

   final RegExp escapeRegexp = new RegExp('["{}<>|]');

   /// Escapes characters in [text] so it can be used as part of a label.
   String escapeLabel(String text) {
     return text.replaceAllMapped(escapeRegexp, (m) => '\\${m.group(0)}');
   }

   /// Creates an edge from [src] to [dst].
   ///
   /// If [dst] is a record type node, [port] may refer to one of the fields
   /// defined in that record (e.g. `obj`, `arg0`, `arg1`, etc)
   void addEdge(TypeInformation src, TypeInformation dst,
       {String port, String color: 'black'}) {
     if (isExternal(src) && isExternal(dst)) {
       return; // Do not add edges between external nodes.
     }
     String dstText = getNode(dst);
     if (port != null) {
       dstText += ':$port';
     }
     if (src is ConcreteTypeInformation) {
       // Concrete types can have a huge number of uses which will flood the
       // graph with very long hard-to-follow edges. Copy the concrete nodes
       // for every use to enhance readability.
       int id = getFreshId();
       String type = escapeLabel('${formatType(src.type)}');
       String text = 'Concrete';
       String label = '{$text|<returnType> $type}';
       append('$id [shape=record,style=dotted,label="$label"]');
       append('$id -> $dstText [color="$color"]');
     } else {
       append('${getNode(src)}:returnType -> $dstText [color="$color"]');
     }
   }

   // Some graphs are flooded by a huge number of phi and narrow nodes.
   // We color the nodes so the "interesting" nodes stand out more.
   static const String defaultNodeColor = '#eeffee';
   static const String phiColor = '#eeffff';
   static const String narrowColor = phiColor;
   static const String callColor = '#ffffee';

   // Colors for edges based on whether they were added or removed during the
   // analysis.
   static const String unchangedEdge = 'black';
   static const String addedEdge = 'green4';
   static const String removedEdge = 'red3';
   static const String temporaryEdge = 'orange'; // Added and then removed again.

   bool isExternal(TypeInformation node) {
     return node != returnValue && node.contextMember != element;
   }

   String getStyleForNode(TypeInformation node, String color) {
     return isExternal(node)
         ? 'style=dotted'
         : 'style=filled,fillcolor="$color"';
   }

   /// Adds details that are not specific to a subclass of [TypeInformation].
   String appendDetails(TypeInformation node, String text) {
     if (node == returnValue) {
       return '$text\n(return value)';
     }
     if (node.contextMember != null && node.contextMember != element) {
       return '$text\n(from ${node.contextMember})';
     }
     return text;
   }

   /// Creates a node for [node] displaying the given [text] in its box.
   ///
   /// [inputs] specify named inputs to the node. If omitted, edges will be
   /// based on [node.assignments].
   void addNode(TypeInformation node, String text,
       {String color: defaultNodeColor, Map<String, TypeInformation> inputs}) {
     seen.add(node);
     String style = getStyleForNode(node, color);
     text = appendDetails(node, text);
     text = escapeLabel(text);
     String id = getNode(node);
     String returnType = escapeLabel(formatType(node.type));
     if (inputs != null) {
       Iterable<String> keys = inputs.keys.where((key) => inputs[key] != null);
       String header = keys.map((key) => '<a$key> $key').join('|');
       String label = '{{$header}|$text|<returnType> $returnType}';
       append('$id [shape=record,label="$label",$style]');
       for (String key in keys) {
         addEdge(inputs[key], node, port: 'a$key');
       }
     } else {
       String label = '{$text|<returnType> $returnType}';
       append('$id [shape=record,label="$label",$style]');
       // Add assignment edges. Color the edges based on whether they were
       // added, removed, temporary, or unchanged.
       dynamic originalSet = global.assignmentsBeforeAnalysis[node] ?? const [];
       var tracerSet = global.assignmentsBeforeTracing[node] ?? const [];
       var currentSet = node.assignments.toSet();
       for (TypeInformation assignment in currentSet) {
         String color =
             originalSet.contains(assignment) ? unchangedEdge : addedEdge;
         addEdge(assignment, node, color: color);
       }
       for (TypeInformation assignment in originalSet) {
         if (!currentSet.contains(assignment)) {
           addEdge(assignment, node, color: removedEdge);
         }
       }
       for (TypeInformation assignment in tracerSet) {
         if (!currentSet.contains(assignment) &&
             !originalSet.contains(assignment)) {
           addEdge(assignment, node, color: temporaryEdge);
         }
       }
     }
     if (PRINT_GRAPH_ALL_NODES) {
       for (TypeInformation user in node.users) {
         if (!isExternal(user)) {
           visit(user);
         }
       }
     }
   }

   void visitNarrowTypeInformation(NarrowTypeInformation info) {
     // Omit unused Narrows.
     if (!PRINT_GRAPH_ALL_NODES && info.users.isEmpty) return;
     addNode(info, 'Narrow\n${formatType(info.typeAnnotation)}',
         color: narrowColor);
   }

   void visitPhiElementTypeInformation(PhiElementTypeInformation info) {
     // Omit unused Phis.
     if (!PRINT_GRAPH_ALL_NODES && info.users.isEmpty) return;
     addNode(info, 'Phi ${info.variable?.name ?? ''}', color: phiColor);
   }

   void visitElementInContainerTypeInformation(
       ElementInContainerTypeInformation info) {
     addNode(info, 'ElementInContainer');
   }

   void visitKeyInMapTypeInformation(KeyInMapTypeInformation info) {
     addNode(info, 'KeyInMap');
   }

   void visitValueInMapTypeInformation(ValueInMapTypeInformation info) {
     addNode(info, 'ValueInMap');
   }

   void visitListTypeInformation(ListTypeInformation info) {
     addNode(info, 'List');
   }

   void visitMapTypeInformation(MapTypeInformation info) {
     addNode(info, 'Map');
   }

   void visitConcreteTypeInformation(ConcreteTypeInformation info) {
     addNode(info, 'Concrete');
   }

   void visitStringLiteralTypeInformation(StringLiteralTypeInformation info) {
     String text = shorten(info.value).replaceAll('\n', '\\n');
     addNode(info, 'StringLiteral\n"$text"');
   }

   void visitBoolLiteralTypeInformation(BoolLiteralTypeInformation info) {
     addNode(info, 'BoolLiteral\n${info.value}');
   }

   void handleCall(CallSiteTypeInformation info, String text,
       Map<String, TypeInformation> inputs) {
     String sourceCode = shorten('${info.debugName}');
     text = '$text\n$sourceCode';
     if (info.arguments != null) {
       for (int i = 0; i < info.arguments.positional.length; ++i) {
         inputs['arg$i'] = info.arguments.positional[i];
       }
       for (String argName in info.arguments.named.keys) {
         inputs[argName] = info.arguments.named[argName];
       }
     }
     addNode(info, text, color: callColor, inputs: inputs);
   }

   void visitClosureCallSiteTypeInformation(
       ClosureCallSiteTypeInformation info) {
     handleCall(info, 'ClosureCallSite', {});
   }

   void visitStaticCallSiteTypeInformation(StaticCallSiteTypeInformation info) {
     handleCall(info, 'StaticCallSite', {});
   }

   void visitDynamicCallSiteTypeInformation(
       DynamicCallSiteTypeInformation info) {
     handleCall(info, 'DynamicCallSite', {'obj': info.receiver});
   }

   void visitMemberTypeInformation(MemberTypeInformation info) {
     addNode(info, 'Member\n${info.debugName}');
   }

   void visitParameterTypeInformation(ParameterTypeInformation info) {
     addNode(info, 'Parameter ${info.debugName}');
   }

   void visitClosureTypeInformation(ClosureTypeInformation info) {
     String text = shorten('${info.debugName}');
     addNode(info, 'Closure\n$text');
   }

   void visitAwaitTypeInformation(AwaitTypeInformation info) {
     String text = shorten('${info.debugName}');
     addNode(info, 'Await\n$text');
   }

   void visitYieldTypeInformation(YieldTypeInformation info) {
     String text = shorten('${info.debugName}');
     addNode(info, 'Yield\n$text');
   }
 }
	// 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 dart2js.inferrer.type_graph_dump;

	import '../../compiler_new.dart';
	import '../elements/entities.dart';
	import '../elements/entity_utils.dart' as utils;
	import '../types/abstract_value_domain.dart';
	import 'inferrer_engine.dart';
	import 'type_graph_nodes.dart';
	import 'debug.dart';

	/// Dumps the type inference graph in Graphviz Dot format into the `typegraph`
	/// subfolder of the current working directory. Each function body is dumped in
	/// a separate file.
	///
	/// The resulting .dot files must be processed using the Graphviz `dot` command,
	/// which can be obtained from `http://www.graphviz.org`, or installed using
	/// most package managers (search for `graphviz` or `dot`).
	///
	/// Example commands:
	///
	/// dot -Tpng -O typegraph/main.dot
	/// open typegraph/main.dot.png
	///
	/// dot -Tpng -O typegraph/dart._internal.Sort._dualPivotQuicksort.dot
	/// open typegraph/dart._internal.Sort._dualPivotQuicksort.dot.png
	///
	class TypeGraphDump {
	static const String outputDir = 'typegraph';

	final CompilerOutput compilerOutput;
	final InferrerEngine inferrer;
	final Map<TypeInformation, Set<TypeInformation>> assignmentsBeforeAnalysis =
	<TypeInformation, Set<TypeInformation>>{};
	final Map<TypeInformation, Set<TypeInformation>> assignmentsBeforeTracing =
	<TypeInformation, Set<TypeInformation>>{};
	final Set<String> usedFilenames = new Set<String>();

	TypeGraphDump(this.compilerOutput, this.inferrer);

	/// Take a copy of the assignment set for each node, since that may change
	/// during the analysis.
	void beforeAnalysis() {
	for (TypeInformation node in inferrer.types.allTypes) {
	Set<TypeInformation> copy = node.assignments.toSet();
	if (!copy.isEmpty) {
	assignmentsBeforeAnalysis[node] = copy;
	}
	}
	}

	/// Like [beforeAnalysis], takes a copy of the assignment sets.
	void beforeTracing() {
	for (TypeInformation node in inferrer.types.allTypes) {
	Set<TypeInformation> copy = node.assignments.toSet();
	if (!copy.isEmpty) {
	assignmentsBeforeTracing[node] = copy;
	}
	}
	}

	/// Dumps the entire graph.
	void afterAnalysis() {
	// Group all the type nodes by their context member.
	Map<MemberEntity, List<TypeInformation>> nodes =
	<MemberEntity, List<TypeInformation>>{};
	for (TypeInformation node in inferrer.types.allTypes) {
	if (node.contextMember != null) {
	nodes
	.putIfAbsent(node.contextMember, () => <TypeInformation>[])
	.add(node);
	}
	}
	// Print every group separately.
	for (MemberEntity element in nodes.keys) {
	OutputSink output;
	try {
	String name = filenameFromElement(element);
	output = compilerOutput.createOutputSink(
	'$outputDir/$name', 'dot', OutputType.debug);
	_GraphGenerator visitor = new _GraphGenerator(
	this, element, output, inferrer.abstractValueDomain.getCompactText);
	for (TypeInformation node in nodes[element]) {
	visitor.visit(node);
	}
	visitor.addMissingNodes();
	visitor.finish();
	} finally {
	if (output != null) {
	output.close();
	}
	}
	}
	}

	/// Returns the filename (without extension) in which to dump the type
	/// graph for [element].
	///
	/// Will never return the a given filename more than once, even if called with
	/// the same element.
	String filenameFromElement(MemberEntity element) {
	// The toString method of elements include characters that are unsuitable
	// for URIs and file systems.
	List<String> parts = <String>[];
	parts.add(element.library.canonicalUri.pathSegments.last);
	parts.add(element.enclosingClass?.name);
	if (element.isGetter) {
	parts.add('get-${element.name}');
	} else if (element.isSetter) {
	parts.add('set-${element.name}');
	} else if (element.isConstructor) {
	if (element.name.isEmpty) {
	parts.add('-constructor');
	} else {
	parts.add(element.name);
	}
	} else {
	parts.add(
	utils.operatorNameToIdentifier(element.name).replaceAll(r'$', '-'));
	}
	String filename = parts.where((x) => x != null && x != '').join('.');
	if (usedFilenames.add(filename)) return filename;
	// The filename has already been used by another method. Append a serial
	// number to ensure we don't overwrite it.
	int serialNumber = 2;
	while (!usedFilenames.add('$filename-$serialNumber')) {
	++serialNumber;
	}
	return '$filename-$serialNumber';
	}
	}

	/// Builds the Graphviz Dot file for one function body.
	class _GraphGenerator extends TypeInformationVisitor {
	final TypeGraphDump global;
	final Set<TypeInformation> seen = new Set<TypeInformation>();
	final List<TypeInformation> worklist = new List<TypeInformation>();
	final Map<TypeInformation, int> nodeId = <TypeInformation, int>{};
	final String Function(AbstractValue) formatType;
	int usedIds = 0;
	final OutputSink output;
	final MemberEntity element;
	TypeInformation returnValue;

	_GraphGenerator(this.global, this.element, this.output, this.formatType) {
	returnValue = global.inferrer.types.getInferredTypeOfMember(element);
	getNode(returnValue); // Ensure return value is part of graph.
	append('digraph {');
	}

	void finish() {
	append('}');
	}

	/// Ensures that all nodes which have been referenced are generated.
	///
	/// Sometimes an input to a TypeInformation node does not belong to the same
	/// function body, and the graph looks confusing if they are missing.
	void addMissingNodes() {
	while (worklist.isNotEmpty) {
	TypeInformation node = worklist.removeLast();
	assert(nodeId.containsKey(node));
	visit(node);
	}
	}

	void visit(TypeInformation info) {
	if (seen.contains(info)) return;
	info.accept(this);
	}

	void append(String string) {
	output..add(string)..add('\n');
	}

	String shorten(String text) {
	if (text.length > 40) {
	return text.substring(0, 19) + '...' + text.substring(text.length - 18);
	}
	return text;
	}

	int getFreshId() => ++usedIds;

	/// Obtains a unique ID for the node representing [info].
	String getNode(TypeInformation info) {
	int id = nodeId.putIfAbsent(info, () {
	worklist.add(info); // Ensure that the referenced node is generated.
	return getFreshId();
	});
	return '$id';
	}

	final RegExp escapeRegexp = new RegExp('["{}<>\|]');

	/// Escapes characters in [text] so it can be used as part of a label.
	String escapeLabel(String text) {
	return text.replaceAllMapped(escapeRegexp, (m) => '\\${m.group(0)}');
	}

	/// Creates an edge from [src] to [dst].
	///
	/// If [dst] is a record type node, [port] may refer to one of the fields
	/// defined in that record (e.g. `obj`, `arg0`, `arg1`, etc)
	void addEdge(TypeInformation src, TypeInformation dst,
	{String port, String color: 'black'}) {
	if (isExternal(src) && isExternal(dst)) {
	return; // Do not add edges between external nodes.
	}
	String dstText = getNode(dst);
	if (port != null) {
	dstText += ':$port';
	}
	if (src is ConcreteTypeInformation) {
	// Concrete types can have a huge number of uses which will flood the
	// graph with very long hard-to-follow edges. Copy the concrete nodes
	// for every use to enhance readability.
	int id = getFreshId();
	String type = escapeLabel('${formatType(src.type)}');
	String text = 'Concrete';
	String label = '{$text\|<returnType> $type}';
	append('$id [shape=record,style=dotted,label="$label"]');
	append('$id -> $dstText [color="$color"]');
	} else {
	append('${getNode(src)}:returnType -> $dstText [color="$color"]');
	}
	}

	// Some graphs are flooded by a huge number of phi and narrow nodes.
	// We color the nodes so the "interesting" nodes stand out more.
	static const String defaultNodeColor = '#eeffee';
	static const String phiColor = '#eeffff';
	static const String narrowColor = phiColor;
	static const String callColor = '#ffffee';

	// Colors for edges based on whether they were added or removed during the
	// analysis.
	static const String unchangedEdge = 'black';
	static const String addedEdge = 'green4';
	static const String removedEdge = 'red3';
	static const String temporaryEdge = 'orange'; // Added and then removed again.

	bool isExternal(TypeInformation node) {
	return node != returnValue && node.contextMember != element;
	}

	String getStyleForNode(TypeInformation node, String color) {
	return isExternal(node)
	? 'style=dotted'
	: 'style=filled,fillcolor="$color"';
	}

	/// Adds details that are not specific to a subclass of [TypeInformation].
	String appendDetails(TypeInformation node, String text) {
	if (node == returnValue) {
	return '$text\n(return value)';
	}
	if (node.contextMember != null && node.contextMember != element) {
	return '$text\n(from ${node.contextMember})';
	}
	return text;
	}

	/// Creates a node for [node] displaying the given [text] in its box.
	///
	/// [inputs] specify named inputs to the node. If omitted, edges will be
	/// based on [node.assignments].
	void addNode(TypeInformation node, String text,
	{String color: defaultNodeColor, Map<String, TypeInformation> inputs}) {
	seen.add(node);
	String style = getStyleForNode(node, color);
	text = appendDetails(node, text);
	text = escapeLabel(text);
	String id = getNode(node);
	String returnType = escapeLabel(formatType(node.type));
	if (inputs != null) {
	Iterable<String> keys = inputs.keys.where((key) => inputs[key] != null);
	String header = keys.map((key) => '<a$key> $key').join('\|');
	String label = '{{$header}\|$text\|<returnType> $returnType}';
	append('$id [shape=record,label="$label",$style]');
	for (String key in keys) {
	addEdge(inputs[key], node, port: 'a$key');
	}
	} else {
	String label = '{$text\|<returnType> $returnType}';
	append('$id [shape=record,label="$label",$style]');
	// Add assignment edges. Color the edges based on whether they were
	// added, removed, temporary, or unchanged.
	dynamic originalSet = global.assignmentsBeforeAnalysis[node] ?? const [];
	var tracerSet = global.assignmentsBeforeTracing[node] ?? const [];
	var currentSet = node.assignments.toSet();
	for (TypeInformation assignment in currentSet) {
	String color =
	originalSet.contains(assignment) ? unchangedEdge : addedEdge;
	addEdge(assignment, node, color: color);
	}
	for (TypeInformation assignment in originalSet) {
	if (!currentSet.contains(assignment)) {
	addEdge(assignment, node, color: removedEdge);
	}
	}
	for (TypeInformation assignment in tracerSet) {
	if (!currentSet.contains(assignment) &&
	!originalSet.contains(assignment)) {
	addEdge(assignment, node, color: temporaryEdge);
	}
	}
	}
	if (PRINT_GRAPH_ALL_NODES) {
	for (TypeInformation user in node.users) {
	if (!isExternal(user)) {
	visit(user);
	}
	}
	}
	}

	void visitNarrowTypeInformation(NarrowTypeInformation info) {
	// Omit unused Narrows.
	if (!PRINT_GRAPH_ALL_NODES && info.users.isEmpty) return;
	addNode(info, 'Narrow\n${formatType(info.typeAnnotation)}',
	color: narrowColor);
	}

	void visitPhiElementTypeInformation(PhiElementTypeInformation info) {
	// Omit unused Phis.
	if (!PRINT_GRAPH_ALL_NODES && info.users.isEmpty) return;
	addNode(info, 'Phi ${info.variable?.name ?? ''}', color: phiColor);
	}

	void visitElementInContainerTypeInformation(
	ElementInContainerTypeInformation info) {
	addNode(info, 'ElementInContainer');
	}

	void visitKeyInMapTypeInformation(KeyInMapTypeInformation info) {
	addNode(info, 'KeyInMap');
	}

	void visitValueInMapTypeInformation(ValueInMapTypeInformation info) {
	addNode(info, 'ValueInMap');
	}

	void visitListTypeInformation(ListTypeInformation info) {
	addNode(info, 'List');
	}

	void visitMapTypeInformation(MapTypeInformation info) {
	addNode(info, 'Map');
	}

	void visitConcreteTypeInformation(ConcreteTypeInformation info) {
	addNode(info, 'Concrete');
	}

	void visitStringLiteralTypeInformation(StringLiteralTypeInformation info) {
	String text = shorten(info.value).replaceAll('\n', '\\n');
	addNode(info, 'StringLiteral\n"$text"');
	}

	void visitBoolLiteralTypeInformation(BoolLiteralTypeInformation info) {
	addNode(info, 'BoolLiteral\n${info.value}');
	}

	void handleCall(CallSiteTypeInformation info, String text,
	Map<String, TypeInformation> inputs) {
	String sourceCode = shorten('${info.debugName}');
	text = '$text\n$sourceCode';
	if (info.arguments != null) {
	for (int i = 0; i < info.arguments.positional.length; ++i) {
	inputs['arg$i'] = info.arguments.positional[i];
	}
	for (String argName in info.arguments.named.keys) {
	inputs[argName] = info.arguments.named[argName];
	}
	}
	addNode(info, text, color: callColor, inputs: inputs);
	}

	void visitClosureCallSiteTypeInformation(
	ClosureCallSiteTypeInformation info) {
	handleCall(info, 'ClosureCallSite', {});
	}

	void visitStaticCallSiteTypeInformation(StaticCallSiteTypeInformation info) {
	handleCall(info, 'StaticCallSite', {});
	}

	void visitDynamicCallSiteTypeInformation(
	DynamicCallSiteTypeInformation info) {
	handleCall(info, 'DynamicCallSite', {'obj': info.receiver});
	}

	void visitMemberTypeInformation(MemberTypeInformation info) {
	addNode(info, 'Member\n${info.debugName}');
	}

	void visitParameterTypeInformation(ParameterTypeInformation info) {
	addNode(info, 'Parameter ${info.debugName}');
	}

	void visitClosureTypeInformation(ClosureTypeInformation info) {
	String text = shorten('${info.debugName}');
	addNode(info, 'Closure\n$text');
	}

	void visitAwaitTypeInformation(AwaitTypeInformation info) {
	String text = shorten('${info.debugName}');
	addNode(info, 'Await\n$text');
	}

	void visitYieldTypeInformation(YieldTypeInformation info) {
	String text = shorten('${info.debugName}');
	addNode(info, 'Yield\n$text');
	}
	}