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

 // Copyright (c) 2013, 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.

 part of type_graph_inferrer;

 // A set of selectors we know do not escape the elements inside the
 // list.
 Set<String> doesNotEscapeListSet = new Set<String>.from(
   const <String>[
     // From Object.
     '==',
     'hashCode',
     'toString',
     'noSuchMethod',
     'runtimeType',

     // From Iterable.
     'isEmpty',
     'isNotEmpty',
     'length',
     'any',
     'contains',
     'every',
     'join',

     // From List.
     'add',
     'addAll',
     'clear',
     'fillRange',
     'indexOf',
     'insert',
     'insertAll',
     'lastIndexOf',
     'remove',
     'removeRange',
     'replaceRange',
     'setAll',
     'setRange',
     'shuffle',
     '[]=',

     // From JSArray.
     'checkMutable',
     'checkGrowable',
   ]);

 Set<String> doesNotEscapeMapSet = new Set<String>.from(
   const <String>[
     // From Object.
     '==',
     'hashCode',
     'toString',
     'noSuchMethod',
     'runtimeType',
     // from Map.
     'isEmpty',
     'isNotEmpty',
     'length',
     'clear',
     'containsKey',
     'containsValue',
     '[]=',
     // [keys] only allows key values to escape, which we do not track.
     'keys'
   ]);

 abstract class TracerVisitor<T extends TypeInformation>
     implements TypeInformationVisitor {
   final T tracedType;
   final TypeGraphInferrerEngine inferrer;
   final Compiler compiler;

   static const int MAX_ANALYSIS_COUNT = 16;
   final Setlet<Element> analyzedElements = new Setlet<Element>();

   TracerVisitor(this.tracedType, TypeGraphInferrerEngine inferrer)
       : this.inferrer = inferrer, this.compiler = inferrer.compiler;

   // Work list that gets populated with [TypeInformation] that could
   // contain the container.
   final List<TypeInformation> workList = <TypeInformation>[];

   // Work list of lists to analyze after analyzing the users of a
   // [TypeInformation]. We know the [tracedType] has been stored in these
   // lists and we must check how it escapes from these lists.
   final List<ListTypeInformation> listsToAnalyze =
       <ListTypeInformation>[];
   // Work list of maps to analyze after analyzing the users of a
   // [TypeInformation]. We know the [tracedType] has been stored in these
   // maps and we must check how it escapes from these maps.
   final List<MapTypeInformation> mapsToAnalyze = <MapTypeInformation>[];

   final Setlet<TypeInformation> flowsInto = new Setlet<TypeInformation>();

   // The current [TypeInformation] in the analysis.
   TypeInformation currentUser;
   bool continueAnalyzing = true;

   void addNewEscapeInformation(TypeInformation info) {
     if (flowsInto.contains(info)) return;
     flowsInto.add(info);
     workList.add(info);
   }

   bool _wouldBeTooManyUsers(Set users) {
     int seenSoFar = analyzedElements.length;
     if (seenSoFar + users.length <= MAX_ANALYSIS_COUNT) return false;
     int actualWork = users
         .where((TypeInformation user) => !analyzedElements.contains(user.owner))
         .length;
     return seenSoFar + actualWork > MAX_ANALYSIS_COUNT;
   }

   void analyze() {
     // Collect the [TypeInformation] where the list can flow in,
     // as well as the operations done on all these [TypeInformation]s.
     addNewEscapeInformation(tracedType);
     while (!workList.isEmpty) {
       currentUser = workList.removeLast();
       if (_wouldBeTooManyUsers(currentUser.users)) {
         bailout('Too many users');
         break;
       }
       for (TypeInformation info in currentUser.users) {
         analyzedElements.add(info.owner);
         info.accept(this);
       }
       while (!listsToAnalyze.isEmpty) {
         analyzeStoredIntoList(listsToAnalyze.removeLast());
       }
       while (!mapsToAnalyze.isEmpty) {
         analyzeStoredIntoMap(mapsToAnalyze.removeLast());
       }
       if (!continueAnalyzing) break;
     }
   }

   void bailout(String reason) {
     if (_VERBOSE) {
       print('Bailing out on $tracedType because: $reason');
     }
     continueAnalyzing = false;
   }

   void visitAwaitTypeInformation(AwaitTypeInformation info) {
     bailout("Passed through await");
   }

   void visitNarrowTypeInformation(NarrowTypeInformation info) {
     addNewEscapeInformation(info);
   }

   void visitPhiElementTypeInformation(PhiElementTypeInformation info) {
     addNewEscapeInformation(info);
   }

   void visitElementInContainerTypeInformation(
       ElementInContainerTypeInformation info) {
     addNewEscapeInformation(info);
   }

   void visitKeyInMapTypeInformation(KeyInMapTypeInformation info) {
     // We do not track the use of keys from a map, so we have to bail.
     bailout('Used as key in Map');
   }

   void visitValueInMapTypeInformation(ValueInMapTypeInformation info) {
     addNewEscapeInformation(info);
   }

   void visitListTypeInformation(ListTypeInformation info) {
     listsToAnalyze.add(info);
   }

   void visitMapTypeInformation(MapTypeInformation info) {
     mapsToAnalyze.add(info);
   }
   void visitConcreteTypeInformation(ConcreteTypeInformation info) {}

   void visitStringLiteralTypeInformation(StringLiteralTypeInformation info) {}

   void visitClosureTypeInformation(ClosureTypeInformation info) {}

   void visitClosureCallSiteTypeInformation(
       ClosureCallSiteTypeInformation info) {}

   visitStaticCallSiteTypeInformation(StaticCallSiteTypeInformation info) {
     Element called = info.calledElement;
     if (inferrer.types.getInferredTypeOf(called) == currentUser) {
       addNewEscapeInformation(info);
     }
   }

   void analyzeStoredIntoList(ListTypeInformation list) {
     inferrer.analyzeListAndEnqueue(list);
     if (list.bailedOut) {
       bailout('Stored in a list that bailed out');
     } else {
       list.flowsInto.forEach((flow) {
         flow.users.forEach((user) {
           if (user is !DynamicCallSiteTypeInformation) return;
           if (user.receiver != flow) return;
           if (inferrer._returnsListElementTypeSet.contains(user.selector)) {
             addNewEscapeInformation(user);
           } else if (!doesNotEscapeListSet.contains(user.selector.name)) {
             bailout('Escape from a list via [${user.selector.name}]');
           }
         });
       });
     }
   }

   void analyzeStoredIntoMap(MapTypeInformation map) {
     inferrer.analyzeMapAndEnqueue(map);
     if (map.bailedOut) {
       bailout('Stored in a map that bailed out');
     } else {
       map.flowsInto.forEach((flow) {
         flow.users.forEach((user) {
           if (user is !DynamicCallSiteTypeInformation) return;
           if (user.receiver != flow) return;
           if (user.selector.isIndex) {
             addNewEscapeInformation(user);
           } else if (!doesNotEscapeMapSet.contains(user.selector.name)) {
             bailout('Escape from a map via [${user.selector.name}]');
           }
         });
       });
     }
   }

   /**
    * Checks whether this is a call to a list adding method. The definition
    * of what list adding means has to stay in sync with
    * [isParameterOfListAddingMethod].
    */
   bool isAddedToContainer(DynamicCallSiteTypeInformation info) {
     if (info.arguments == null) return false;
     var receiverType = info.receiver.type;
     if (!receiverType.isContainer) return false;
     String selectorName = info.selector.name;
     List<TypeInformation> arguments = info.arguments.positional;
     return (selectorName == '[]=' && currentUser == arguments[1])
         || (selectorName == 'insert' && currentUser == arguments[1])
         || (selectorName == 'add' && currentUser == arguments[0]);
   }

   bool isIndexSetOnMap(DynamicCallSiteTypeInformation info) {
     if (info.arguments == null) return false;
     var receiverType = info.receiver.type;
     if (!receiverType.isMap) return false;
     return info.selector.name == '[]=';
   }

   /**
    * Checks whether this is a call to a map adding method for values. The
    * definition of map adding method has to stay in sync with
    * [isParameterOfMapAddingMethod].
    */
   bool isValueAddedToMap(DynamicCallSiteTypeInformation info) {
      return isIndexSetOnMap(info) &&
          currentUser == info.arguments.positional[1];
   }

   /**
    * Checks whether this is a call to a map adding method for keys. The
    * definition of map adding method has to stay in sync with
    * [isParameterOfMapAddingMethod].
    */
   bool isKeyAddedToMap(DynamicCallSiteTypeInformation info) {
     return isIndexSetOnMap(info) &&
         currentUser == info.arguments.positional[0];
   }

   void visitDynamicCallSiteTypeInformation(
       DynamicCallSiteTypeInformation info) {
     if (isAddedToContainer(info)) {
       ContainerTypeMask mask = info.receiver.type;

       if (mask.allocationNode != null) {
         ListTypeInformation list =
             inferrer.types.allocatedLists[mask.allocationNode];
         listsToAnalyze.add(list);
       } else {
         // The [ContainerTypeMask] is a union of two containers, and
         // we lose track of where these containers have been allocated
         // at this point.
         bailout('Stored in too many containers');
       }
     } else if (isValueAddedToMap(info)) {
       MapTypeMask mask = info.receiver.type;
       if (mask.allocationNode != null) {
         MapTypeInformation map =
             inferrer.types.allocatedMaps[mask.allocationNode];
         mapsToAnalyze.add(map);
       } else {
         // The [MapTypeMask] is a union. See comment for
         // [ContainerTypeMask] above.
         bailout('Stored in too many maps');
       }
     } else if (isKeyAddedToMap(info)) {
       // We do not track the use of keys from a map, so we have to bail.
       bailout('Used as key in Map');
     }

     if (info.targetsIncludeNoSuchMethod &&
         info.arguments != null &&
         info.arguments.contains(currentUser)) {
       bailout('Passed to noSuchMethod');
     }

     Iterable<Element> inferredTargetTypes = info.targets.map((element) {
       return inferrer.types.getInferredTypeOf(element);
     });
     if (inferredTargetTypes.any((user) => user == currentUser)) {
       addNewEscapeInformation(info);
     }
   }

   /**
    * Check whether element is the parameter of a list adding method.
    * The definition of what a list adding method is has to stay in sync with
    * [isAddedToContainer].
    */
   bool isParameterOfListAddingMethod(Element element) {
     if (!element.isParameter) return false;
     if (element.enclosingClass != compiler.backend.listImplementation) {
       return false;
     }
     Element method = element.enclosingElement;
     return (method.name == '[]=')
         || (method.name == 'add')
         || (method.name == 'insert');
   }

   /**
    * Check whether element is the parameter of a list adding method.
    * The definition of what a list adding method is has to stay in sync with
    * [isValueAddedToMap] and [isKeyAddedToMap].
    */
   bool isParameterOfMapAddingMethod(Element element) {
     if (!element.isParameter) return false;
     if (element.enclosingClass != compiler.backend.mapImplementation) {
       return false;
     }
     Element method = element.enclosingElement;
     return (method.name == '[]=');
   }

   bool isClosure(Element element) {
     if (!element.isFunction) return false;
     /// Creating an instance of a class that implements [Function] also
     /// closurizes the corresponding [call] member. We do not currently
     /// track these, thus the check for [isClosurized] on such a method will
     /// return false. Instead we catch that case here for now.
     // TODO(herhut): Handle creation of closures from instances of Function.
     if (element.isInstanceMember &&
         element.name == Compiler.CALL_OPERATOR_NAME) {
       return true;
     }
     Element outermost = element.outermostEnclosingMemberOrTopLevel;
     return outermost.declaration != element.declaration;
   }

   void visitMemberTypeInformation(MemberTypeInformation info) {
     Element element = info.element;
     if (info.isClosurized) {
       bailout('Returned from a closurized method');
     }
     if (isClosure(info.element)) {
       bailout('Returned from a closure');
     }
     if (!inferrer.compiler.backend
         .canBeUsedForGlobalOptimizations(info.element)) {
       bailout('Escape to code that has special backend treatment');
     }
     addNewEscapeInformation(info);
   }

   void visitParameterTypeInformation(ParameterTypeInformation info) {
     ParameterElement element = info.element;
     if (inferrer.isNativeElement(element.functionDeclaration)) {
       bailout('Passed to a native method');
     }
     if (!inferrer.compiler.backend
         .canBeUsedForGlobalOptimizations(info.element)) {
       bailout('Escape to code that has special backend treatment');
     }
     if (isParameterOfListAddingMethod(info.element) ||
         isParameterOfMapAddingMethod(info.element)) {
       // These elements are being handled in
       // [visitDynamicCallSiteTypeInformation].
       return;
     }
     addNewEscapeInformation(info);
   }
 }
	// Copyright (c) 2013, 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.

	part of type_graph_inferrer;

	// A set of selectors we know do not escape the elements inside the
	// list.
	Set<String> doesNotEscapeListSet = new Set<String>.from(
	const <String>[
	// From Object.
	'==',
	'hashCode',
	'toString',
	'noSuchMethod',
	'runtimeType',

	// From Iterable.
	'isEmpty',
	'isNotEmpty',
	'length',
	'any',
	'contains',
	'every',
	'join',

	// From List.
	'add',
	'addAll',
	'clear',
	'fillRange',
	'indexOf',
	'insert',
	'insertAll',
	'lastIndexOf',
	'remove',
	'removeRange',
	'replaceRange',
	'setAll',
	'setRange',
	'shuffle',
	'[]=',

	// From JSArray.
	'checkMutable',
	'checkGrowable',
	]);

	Set<String> doesNotEscapeMapSet = new Set<String>.from(
	const <String>[
	// From Object.
	'==',
	'hashCode',
	'toString',
	'noSuchMethod',
	'runtimeType',
	// from Map.
	'isEmpty',
	'isNotEmpty',
	'length',
	'clear',
	'containsKey',
	'containsValue',
	'[]=',
	// [keys] only allows key values to escape, which we do not track.
	'keys'
	]);

	abstract class TracerVisitor<T extends TypeInformation>
	implements TypeInformationVisitor {
	final T tracedType;
	final TypeGraphInferrerEngine inferrer;
	final Compiler compiler;

	static const int MAX_ANALYSIS_COUNT = 16;
	final Setlet<Element> analyzedElements = new Setlet<Element>();

	TracerVisitor(this.tracedType, TypeGraphInferrerEngine inferrer)
	: this.inferrer = inferrer, this.compiler = inferrer.compiler;

	// Work list that gets populated with [TypeInformation] that could
	// contain the container.
	final List<TypeInformation> workList = <TypeInformation>[];

	// Work list of lists to analyze after analyzing the users of a
	// [TypeInformation]. We know the [tracedType] has been stored in these
	// lists and we must check how it escapes from these lists.
	final List<ListTypeInformation> listsToAnalyze =
	<ListTypeInformation>[];
	// Work list of maps to analyze after analyzing the users of a
	// [TypeInformation]. We know the [tracedType] has been stored in these
	// maps and we must check how it escapes from these maps.
	final List<MapTypeInformation> mapsToAnalyze = <MapTypeInformation>[];

	final Setlet<TypeInformation> flowsInto = new Setlet<TypeInformation>();

	// The current [TypeInformation] in the analysis.
	TypeInformation currentUser;
	bool continueAnalyzing = true;

	void addNewEscapeInformation(TypeInformation info) {
	if (flowsInto.contains(info)) return;
	flowsInto.add(info);
	workList.add(info);
	}

	bool _wouldBeTooManyUsers(Set users) {
	int seenSoFar = analyzedElements.length;
	if (seenSoFar + users.length <= MAX_ANALYSIS_COUNT) return false;
	int actualWork = users
	.where((TypeInformation user) => !analyzedElements.contains(user.owner))
	.length;
	return seenSoFar + actualWork > MAX_ANALYSIS_COUNT;
	}

	void analyze() {
	// Collect the [TypeInformation] where the list can flow in,
	// as well as the operations done on all these [TypeInformation]s.
	addNewEscapeInformation(tracedType);
	while (!workList.isEmpty) {
	currentUser = workList.removeLast();
	if (_wouldBeTooManyUsers(currentUser.users)) {
	bailout('Too many users');
	break;
	}
	for (TypeInformation info in currentUser.users) {
	analyzedElements.add(info.owner);
	info.accept(this);
	}
	while (!listsToAnalyze.isEmpty) {
	analyzeStoredIntoList(listsToAnalyze.removeLast());
	}
	while (!mapsToAnalyze.isEmpty) {
	analyzeStoredIntoMap(mapsToAnalyze.removeLast());
	}
	if (!continueAnalyzing) break;
	}
	}

	void bailout(String reason) {
	if (_VERBOSE) {
	print('Bailing out on $tracedType because: $reason');
	}
	continueAnalyzing = false;
	}

	void visitAwaitTypeInformation(AwaitTypeInformation info) {
	bailout("Passed through await");
	}

	void visitNarrowTypeInformation(NarrowTypeInformation info) {
	addNewEscapeInformation(info);
	}

	void visitPhiElementTypeInformation(PhiElementTypeInformation info) {
	addNewEscapeInformation(info);
	}

	void visitElementInContainerTypeInformation(
	ElementInContainerTypeInformation info) {
	addNewEscapeInformation(info);
	}

	void visitKeyInMapTypeInformation(KeyInMapTypeInformation info) {
	// We do not track the use of keys from a map, so we have to bail.
	bailout('Used as key in Map');
	}

	void visitValueInMapTypeInformation(ValueInMapTypeInformation info) {
	addNewEscapeInformation(info);
	}

	void visitListTypeInformation(ListTypeInformation info) {
	listsToAnalyze.add(info);
	}

	void visitMapTypeInformation(MapTypeInformation info) {
	mapsToAnalyze.add(info);
	}
	void visitConcreteTypeInformation(ConcreteTypeInformation info) {}

	void visitStringLiteralTypeInformation(StringLiteralTypeInformation info) {}

	void visitClosureTypeInformation(ClosureTypeInformation info) {}

	void visitClosureCallSiteTypeInformation(
	ClosureCallSiteTypeInformation info) {}

	visitStaticCallSiteTypeInformation(StaticCallSiteTypeInformation info) {
	Element called = info.calledElement;
	if (inferrer.types.getInferredTypeOf(called) == currentUser) {
	addNewEscapeInformation(info);
	}
	}

	void analyzeStoredIntoList(ListTypeInformation list) {
	inferrer.analyzeListAndEnqueue(list);
	if (list.bailedOut) {
	bailout('Stored in a list that bailed out');
	} else {
	list.flowsInto.forEach((flow) {
	flow.users.forEach((user) {
	if (user is !DynamicCallSiteTypeInformation) return;
	if (user.receiver != flow) return;
	if (inferrer._returnsListElementTypeSet.contains(user.selector)) {
	addNewEscapeInformation(user);
	} else if (!doesNotEscapeListSet.contains(user.selector.name)) {
	bailout('Escape from a list via [${user.selector.name}]');
	}
	});
	});
	}
	}

	void analyzeStoredIntoMap(MapTypeInformation map) {
	inferrer.analyzeMapAndEnqueue(map);
	if (map.bailedOut) {
	bailout('Stored in a map that bailed out');
	} else {
	map.flowsInto.forEach((flow) {
	flow.users.forEach((user) {
	if (user is !DynamicCallSiteTypeInformation) return;
	if (user.receiver != flow) return;
	if (user.selector.isIndex) {
	addNewEscapeInformation(user);
	} else if (!doesNotEscapeMapSet.contains(user.selector.name)) {
	bailout('Escape from a map via [${user.selector.name}]');
	}
	});
	});
	}
	}

	/**
	* Checks whether this is a call to a list adding method. The definition
	* of what list adding means has to stay in sync with
	* [isParameterOfListAddingMethod].
	*/
	bool isAddedToContainer(DynamicCallSiteTypeInformation info) {
	if (info.arguments == null) return false;
	var receiverType = info.receiver.type;
	if (!receiverType.isContainer) return false;
	String selectorName = info.selector.name;
	List<TypeInformation> arguments = info.arguments.positional;
	return (selectorName == '[]=' && currentUser == arguments[1])
	\|\| (selectorName == 'insert' && currentUser == arguments[1])
	\|\| (selectorName == 'add' && currentUser == arguments[0]);
	}

	bool isIndexSetOnMap(DynamicCallSiteTypeInformation info) {
	if (info.arguments == null) return false;
	var receiverType = info.receiver.type;
	if (!receiverType.isMap) return false;
	return info.selector.name == '[]=';
	}

	/**
	* Checks whether this is a call to a map adding method for values. The
	* definition of map adding method has to stay in sync with
	* [isParameterOfMapAddingMethod].
	*/
	bool isValueAddedToMap(DynamicCallSiteTypeInformation info) {
	return isIndexSetOnMap(info) &&
	currentUser == info.arguments.positional[1];
	}

	/**
	* Checks whether this is a call to a map adding method for keys. The
	* definition of map adding method has to stay in sync with
	* [isParameterOfMapAddingMethod].
	*/
	bool isKeyAddedToMap(DynamicCallSiteTypeInformation info) {
	return isIndexSetOnMap(info) &&
	currentUser == info.arguments.positional[0];
	}

	void visitDynamicCallSiteTypeInformation(
	DynamicCallSiteTypeInformation info) {
	if (isAddedToContainer(info)) {
	ContainerTypeMask mask = info.receiver.type;

	if (mask.allocationNode != null) {
	ListTypeInformation list =
	inferrer.types.allocatedLists[mask.allocationNode];
	listsToAnalyze.add(list);
	} else {
	// The [ContainerTypeMask] is a union of two containers, and
	// we lose track of where these containers have been allocated
	// at this point.
	bailout('Stored in too many containers');
	}
	} else if (isValueAddedToMap(info)) {
	MapTypeMask mask = info.receiver.type;
	if (mask.allocationNode != null) {
	MapTypeInformation map =
	inferrer.types.allocatedMaps[mask.allocationNode];
	mapsToAnalyze.add(map);
	} else {
	// The [MapTypeMask] is a union. See comment for
	// [ContainerTypeMask] above.
	bailout('Stored in too many maps');
	}
	} else if (isKeyAddedToMap(info)) {
	// We do not track the use of keys from a map, so we have to bail.
	bailout('Used as key in Map');
	}

	if (info.targetsIncludeNoSuchMethod &&
	info.arguments != null &&
	info.arguments.contains(currentUser)) {
	bailout('Passed to noSuchMethod');
	}

	Iterable<Element> inferredTargetTypes = info.targets.map((element) {
	return inferrer.types.getInferredTypeOf(element);
	});
	if (inferredTargetTypes.any((user) => user == currentUser)) {
	addNewEscapeInformation(info);
	}
	}

	/**
	* Check whether element is the parameter of a list adding method.
	* The definition of what a list adding method is has to stay in sync with
	* [isAddedToContainer].
	*/
	bool isParameterOfListAddingMethod(Element element) {
	if (!element.isParameter) return false;
	if (element.enclosingClass != compiler.backend.listImplementation) {
	return false;
	}
	Element method = element.enclosingElement;
	return (method.name == '[]=')
	\|\| (method.name == 'add')
	\|\| (method.name == 'insert');
	}

	/**
	* Check whether element is the parameter of a list adding method.
	* The definition of what a list adding method is has to stay in sync with
	* [isValueAddedToMap] and [isKeyAddedToMap].
	*/
	bool isParameterOfMapAddingMethod(Element element) {
	if (!element.isParameter) return false;
	if (element.enclosingClass != compiler.backend.mapImplementation) {
	return false;
	}
	Element method = element.enclosingElement;
	return (method.name == '[]=');
	}

	bool isClosure(Element element) {
	if (!element.isFunction) return false;
	/// Creating an instance of a class that implements [Function] also
	/// closurizes the corresponding [call] member. We do not currently
	/// track these, thus the check for [isClosurized] on such a method will
	/// return false. Instead we catch that case here for now.
	// TODO(herhut): Handle creation of closures from instances of Function.
	if (element.isInstanceMember &&
	element.name == Compiler.CALL_OPERATOR_NAME) {
	return true;
	}
	Element outermost = element.outermostEnclosingMemberOrTopLevel;
	return outermost.declaration != element.declaration;
	}

	void visitMemberTypeInformation(MemberTypeInformation info) {
	Element element = info.element;
	if (info.isClosurized) {
	bailout('Returned from a closurized method');
	}
	if (isClosure(info.element)) {
	bailout('Returned from a closure');
	}
	if (!inferrer.compiler.backend
	.canBeUsedForGlobalOptimizations(info.element)) {
	bailout('Escape to code that has special backend treatment');
	}
	addNewEscapeInformation(info);
	}

	void visitParameterTypeInformation(ParameterTypeInformation info) {
	ParameterElement element = info.element;
	if (inferrer.isNativeElement(element.functionDeclaration)) {
	bailout('Passed to a native method');
	}
	if (!inferrer.compiler.backend
	.canBeUsedForGlobalOptimizations(info.element)) {
	bailout('Escape to code that has special backend treatment');
	}
	if (isParameterOfListAddingMethod(info.element) \|\|
	isParameterOfMapAddingMethod(info.element)) {
	// These elements are being handled in
	// [visitDynamicCallSiteTypeInformation].
	return;
	}
	addNewEscapeInformation(info);
	}
	}