| // Copyright (c) 2017, 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. |
| |
| /// Transformations based on type flow analysis. |
| |
| import 'dart:core' hide Type; |
| |
| import 'package:kernel/target/targets.dart'; |
| import 'package:kernel/ast.dart' hide Statement, StatementVisitor; |
| import 'package:kernel/ast.dart' as ast show Statement; |
| import 'package:kernel/clone.dart' show CloneVisitorNotMembers; |
| import 'package:kernel/core_types.dart' show CoreTypes; |
| import 'package:kernel/class_hierarchy.dart' |
| show ClassHierarchy, ClosedWorldClassHierarchy; |
| import 'package:kernel/library_index.dart' show LibraryIndex; |
| import 'package:kernel/type_environment.dart'; |
| |
| import 'analysis.dart'; |
| import 'calls.dart'; |
| import 'signature_shaking.dart'; |
| import 'protobuf_handler.dart' show ProtobufHandler; |
| import 'summary.dart'; |
| import 'table_selector_assigner.dart'; |
| import 'types.dart'; |
| import 'unboxing_info.dart'; |
| import 'utils.dart'; |
| import '../pragma.dart'; |
| import '../devirtualization.dart' show Devirtualization; |
| import '../../metadata/direct_call.dart'; |
| import '../../metadata/inferred_type.dart'; |
| import '../../metadata/procedure_attributes.dart'; |
| import '../../metadata/table_selector.dart'; |
| import '../../metadata/unboxing_info.dart'; |
| import '../../metadata/unreachable.dart'; |
| |
| const bool kDumpClassHierarchy = |
| const bool.fromEnvironment('global.type.flow.dump.class.hierarchy'); |
| |
| /// Whole-program type flow analysis and transformation. |
| /// Assumes strong mode and closed world. |
| Component transformComponent( |
| Target target, CoreTypes coreTypes, Component component, |
| {PragmaAnnotationParser? matcher, |
| bool treeShakeSignatures: true, |
| bool treeShakeWriteOnlyFields: true, |
| bool treeShakeProtobufs: false}) { |
| void ignoreAmbiguousSupertypes(Class cls, Supertype a, Supertype b) {} |
| final hierarchy = new ClassHierarchy(component, coreTypes, |
| onAmbiguousSupertypes: ignoreAmbiguousSupertypes) |
| as ClosedWorldClassHierarchy; |
| final types = new TypeEnvironment(coreTypes, hierarchy); |
| final libraryIndex = new LibraryIndex.all(component); |
| final genericInterfacesInfo = |
| new GenericInterfacesInfoImpl(coreTypes, hierarchy); |
| final protobufHandler = treeShakeProtobufs |
| ? ProtobufHandler.forComponent(component, coreTypes) |
| : null; |
| |
| Statistics.reset(); |
| final analysisStopWatch = new Stopwatch()..start(); |
| |
| MoveFieldInitializers().transformComponent(component); |
| |
| final typeFlowAnalysis = new TypeFlowAnalysis( |
| target, |
| component, |
| coreTypes, |
| hierarchy, |
| genericInterfacesInfo, |
| types, |
| libraryIndex, |
| protobufHandler, |
| matcher); |
| |
| Procedure? main = component.mainMethod; |
| |
| // `main` can be null, roots can also come from @pragma("vm:entry-point"). |
| if (main != null) { |
| final Selector mainSelector = new DirectSelector(main); |
| typeFlowAnalysis.addRawCall(mainSelector); |
| } |
| |
| CleanupAnnotations(coreTypes, libraryIndex, protobufHandler) |
| .visitComponent(component); |
| |
| typeFlowAnalysis.process(); |
| |
| analysisStopWatch.stop(); |
| |
| if (kDumpClassHierarchy) { |
| debugPrint(typeFlowAnalysis.hierarchyCache); |
| } |
| |
| final transformsStopWatch = new Stopwatch()..start(); |
| |
| final treeShaker = new TreeShaker(component, typeFlowAnalysis, |
| treeShakeWriteOnlyFields: treeShakeWriteOnlyFields); |
| treeShaker.transformComponent(component); |
| |
| new TFADevirtualization( |
| component, typeFlowAnalysis, hierarchy, treeShaker.fieldMorpher) |
| .visitComponent(component); |
| |
| final tableSelectorAssigner = new TableSelectorAssigner(component); |
| |
| if (treeShakeSignatures) { |
| final signatureShaker = |
| new SignatureShaker(typeFlowAnalysis, tableSelectorAssigner); |
| signatureShaker.transformComponent(component); |
| } |
| |
| final unboxingInfo = new UnboxingInfoManager(typeFlowAnalysis) |
| ..analyzeComponent(component, typeFlowAnalysis, tableSelectorAssigner); |
| |
| new AnnotateKernel(component, typeFlowAnalysis, treeShaker.fieldMorpher, |
| tableSelectorAssigner, unboxingInfo) |
| .visitComponent(component); |
| |
| transformsStopWatch.stop(); |
| |
| statPrint("TF analysis took ${analysisStopWatch.elapsedMilliseconds}ms"); |
| statPrint("TF transforms took ${transformsStopWatch.elapsedMilliseconds}ms"); |
| |
| Statistics.print("TFA statistics"); |
| |
| return component; |
| } |
| |
| // Move instance field initializers with possible side-effects |
| // into constructors. This makes fields self-contained and |
| // simplifies tree-shaking of fields. |
| class MoveFieldInitializers { |
| void transformComponent(Component component) { |
| for (Library library in component.libraries) { |
| for (Class cls in library.classes) { |
| transformClass(cls); |
| } |
| } |
| } |
| |
| void transformClass(Class cls) { |
| if (cls.fields.isEmpty) return; |
| |
| // Collect instance fields with non-trivial initializers. |
| // Those will be moved into constructors. |
| final List<Field> fields = [ |
| for (Field f in cls.fields) |
| if (!f.isStatic && |
| !f.isLate && |
| f.initializer != null && |
| mayHaveSideEffects(f.initializer!)) |
| f |
| ]; |
| if (fields.isEmpty) return; |
| |
| // Collect non-redirecting constructors. |
| final List<Constructor> constructors = [ |
| for (Constructor c in cls.constructors) |
| if (!_isRedirectingConstructor(c)) c |
| ]; |
| |
| assert(constructors.isNotEmpty); |
| |
| // Move field initializers to constructors. |
| // Clone AST for all constructors except the first. |
| bool isFirst = true; |
| for (Constructor c in constructors) { |
| // Avoid duplicate FieldInitializers in the constructor initializer list. |
| final Set<Field> initializedFields = { |
| for (Initializer init in c.initializers) |
| if (init is FieldInitializer) init.field |
| }; |
| final List<Initializer> newInitializers = []; |
| for (Field f in fields) { |
| Expression initExpr = f.initializer!; |
| if (!isFirst) { |
| initExpr = CloneVisitorNotMembers().clone(initExpr); |
| } |
| final Initializer newInit = initializedFields.contains(f) |
| ? LocalInitializer(VariableDeclaration(null, initializer: initExpr)) |
| : FieldInitializer(f, initExpr); |
| newInit.parent = c; |
| newInitializers.add(newInit); |
| } |
| newInitializers.addAll(c.initializers); |
| c.initializers = newInitializers; |
| isFirst = false; |
| } |
| |
| // Cleanup field initializers. |
| for (Field f in fields) { |
| f.initializer = null; |
| } |
| } |
| |
| bool _isRedirectingConstructor(Constructor c) => |
| c.initializers.last is RedirectingInitializer; |
| } |
| |
| // Pass which removes all annotations except @ExternalName and @pragma |
| // on variables, members, classes and libraries. |
| // May also keep @TagNumber which is used by protobuf handler. |
| class CleanupAnnotations extends RecursiveVisitor { |
| final Class externalNameClass; |
| final Class pragmaClass; |
| final ProtobufHandler? protobufHandler; |
| |
| CleanupAnnotations( |
| CoreTypes coreTypes, LibraryIndex index, this.protobufHandler) |
| : externalNameClass = index.getClass('dart:_internal', 'ExternalName'), |
| pragmaClass = coreTypes.pragmaClass; |
| |
| @override |
| defaultNode(Node node) { |
| if (node is Annotatable && node.annotations.isNotEmpty) { |
| _cleanupAnnotations(node, node.annotations); |
| } |
| super.defaultNode(node); |
| } |
| |
| void _cleanupAnnotations(Node node, List<Expression> annotations) { |
| if (node is VariableDeclaration || |
| node is Member || |
| node is Class || |
| node is Library) { |
| annotations.removeWhere((a) => !_keepAnnotation(a)); |
| } else { |
| annotations.clear(); |
| } |
| } |
| |
| bool _keepAnnotation(Expression annotation) { |
| if (annotation is ConstantExpression) { |
| final constant = annotation.constant; |
| if (constant is InstanceConstant) { |
| final cls = constant.classNode; |
| return (cls == externalNameClass) || |
| (cls == pragmaClass) || |
| (protobufHandler != null && |
| protobufHandler!.usesAnnotationClass(cls)); |
| } |
| } |
| return false; |
| } |
| } |
| |
| /// Devirtualization based on results of type flow analysis. |
| class TFADevirtualization extends Devirtualization { |
| final TypeFlowAnalysis _typeFlowAnalysis; |
| final FieldMorpher fieldMorpher; |
| |
| TFADevirtualization(Component component, this._typeFlowAnalysis, |
| ClassHierarchy hierarchy, this.fieldMorpher) |
| : super(_typeFlowAnalysis.environment.coreTypes, component, hierarchy); |
| |
| @override |
| DirectCallMetadata? getDirectCall(TreeNode node, Member? interfaceTarget, |
| {bool setter = false}) { |
| final callSite = _typeFlowAnalysis.callSite(node); |
| if (callSite != null) { |
| final Member? singleTarget = fieldMorpher |
| .getMorphedMember(callSite.monomorphicTarget, isSetter: setter); |
| if (singleTarget != null) { |
| return new DirectCallMetadata( |
| singleTarget, callSite.isNullableReceiver); |
| } |
| } |
| return null; |
| } |
| } |
| |
| /// Annotates kernel AST with metadata using results of type flow analysis. |
| class AnnotateKernel extends RecursiveVisitor { |
| final TypeFlowAnalysis _typeFlowAnalysis; |
| final FieldMorpher fieldMorpher; |
| final DirectCallMetadataRepository _directCallMetadataRepository; |
| final InferredTypeMetadataRepository _inferredTypeMetadata; |
| final UnreachableNodeMetadataRepository _unreachableNodeMetadata; |
| final ProcedureAttributesMetadataRepository _procedureAttributesMetadata; |
| final TableSelectorMetadataRepository _tableSelectorMetadata; |
| final TableSelectorAssigner _tableSelectorAssigner; |
| final UnboxingInfoMetadataRepository _unboxingInfoMetadata; |
| final UnboxingInfoManager _unboxingInfo; |
| final Class _intClass; |
| late final Constant _nullConstant = NullConstant(); |
| |
| AnnotateKernel(Component component, this._typeFlowAnalysis, this.fieldMorpher, |
| this._tableSelectorAssigner, this._unboxingInfo) |
| : _directCallMetadataRepository = |
| component.metadata[DirectCallMetadataRepository.repositoryTag] |
| as DirectCallMetadataRepository, |
| _inferredTypeMetadata = new InferredTypeMetadataRepository(), |
| _unreachableNodeMetadata = new UnreachableNodeMetadataRepository(), |
| _procedureAttributesMetadata = |
| new ProcedureAttributesMetadataRepository(), |
| _tableSelectorMetadata = new TableSelectorMetadataRepository(), |
| _unboxingInfoMetadata = new UnboxingInfoMetadataRepository(), |
| _intClass = _typeFlowAnalysis.environment.coreTypes.intClass { |
| component.addMetadataRepository(_inferredTypeMetadata); |
| component.addMetadataRepository(_unreachableNodeMetadata); |
| component.addMetadataRepository(_procedureAttributesMetadata); |
| component.addMetadataRepository(_tableSelectorMetadata); |
| component.addMetadataRepository(_unboxingInfoMetadata); |
| } |
| |
| // Query whether a call site was marked as a direct call by the analysis. |
| bool _callSiteUsesDirectCall(TreeNode node) { |
| return _directCallMetadataRepository.mapping.containsKey(node); |
| } |
| |
| InferredType? _convertType(Type type, |
| {bool skipCheck: false, bool receiverNotInt: false}) { |
| Class? concreteClass; |
| Constant? constantValue; |
| bool isInt = false; |
| |
| final nullable = type is NullableType; |
| if (nullable) { |
| type = type.baseType; |
| } |
| |
| if (nullable && type == const EmptyType()) { |
| concreteClass = |
| _typeFlowAnalysis.environment.coreTypes.deprecatedNullClass; |
| constantValue = _nullConstant; |
| } else { |
| concreteClass = type.getConcreteClass(_typeFlowAnalysis.hierarchyCache); |
| |
| if (concreteClass == null) { |
| isInt = type.isSubtypeOf(_typeFlowAnalysis.hierarchyCache, _intClass); |
| } |
| |
| if (type is ConcreteType && !nullable) { |
| constantValue = type.constant; |
| } |
| } |
| |
| List<DartType?>? typeArgs; |
| if (type is ConcreteType && type.typeArgs != null) { |
| typeArgs = type.typeArgs! |
| .take(type.numImmediateTypeArgs) |
| .map((t) => |
| t is UnknownType ? null : (t as RuntimeType).representedType) |
| .toList(); |
| } |
| |
| if (concreteClass != null || |
| !nullable || |
| isInt || |
| constantValue != null || |
| skipCheck || |
| receiverNotInt) { |
| return new InferredType(concreteClass, nullable, isInt, constantValue, |
| exactTypeArguments: typeArgs, |
| skipCheck: skipCheck, |
| receiverNotInt: receiverNotInt); |
| } |
| |
| return null; |
| } |
| |
| void _setInferredType(TreeNode node, Type type, |
| {bool skipCheck: false, bool receiverNotInt: false}) { |
| final inferredType = _convertType(type, |
| skipCheck: skipCheck, receiverNotInt: receiverNotInt); |
| if (inferredType != null) { |
| _inferredTypeMetadata.mapping[node] = inferredType; |
| } |
| } |
| |
| void _setUnreachable(TreeNode node) { |
| _unreachableNodeMetadata.mapping[node] = const UnreachableNode(); |
| } |
| |
| void _annotateCallSite(TreeNode node, Member? interfaceTarget) { |
| final callSite = _typeFlowAnalysis.callSite(node); |
| if (callSite == null) return; |
| if (!callSite.isReachable) { |
| _setUnreachable(node); |
| return; |
| } |
| |
| final bool markSkipCheck = !callSite.useCheckedEntry && |
| (node is InstanceInvocation || |
| node is DynamicInvocation || |
| node is EqualsCall || |
| node is InstanceSet || |
| node is DynamicSet); |
| |
| bool markReceiverNotInt = false; |
| |
| if (!callSite.receiverMayBeInt) { |
| // No information is needed for static calls. |
| if (node is! StaticInvocation && |
| node is! StaticSet && |
| node is! StaticGet && |
| node is! StaticTearOff) { |
| // The compiler uses another heuristic in addition to the call-site |
| // annotation: if the call-site is non-dynamic and the interface target does |
| // not exist in the parent chain of _Smi (int is used as an approxmiation |
| // here), then the receiver cannot be _Smi. This heuristic covers most |
| // cases, so we skip these to avoid showering the AST with annotations. |
| if (interfaceTarget == null || |
| _typeFlowAnalysis.hierarchyCache.hierarchy.isSubtypeOf( |
| _typeFlowAnalysis.hierarchyCache.coreTypes.intClass, |
| interfaceTarget.enclosingClass!)) { |
| markReceiverNotInt = true; |
| } |
| } |
| } |
| |
| // If the call is not marked as 'isResultUsed', the 'resultType' will |
| // not be observed (i.e., it will always be EmptyType). This is the |
| // case even if the result actually might be used but is not used by |
| // the summary, e.g. if the result is an argument to a closure call. |
| // Therefore, we need to pass in 'NullableType(AnyType)' as the |
| // inferred result type here (since we don't know what it actually |
| // is). |
| final Type resultType = callSite.isResultUsed |
| ? callSite.resultType |
| : NullableType(const AnyType()); |
| |
| if (markSkipCheck || markReceiverNotInt || callSite.isResultUsed) { |
| _setInferredType(node, resultType, |
| skipCheck: markSkipCheck, receiverNotInt: markReceiverNotInt); |
| } |
| |
| // Tell the table selector assigner about the callsite. |
| final Selector selector = callSite.selector; |
| if (selector is InterfaceSelector && !_callSiteUsesDirectCall(node)) { |
| if (node is InstanceGet || node is InstanceTearOff) { |
| _tableSelectorAssigner.registerGetterCall( |
| selector.member, callSite.isNullableReceiver); |
| } else { |
| assert(node is InstanceInvocation || |
| node is EqualsCall || |
| node is InstanceSet); |
| _tableSelectorAssigner.registerMethodOrSetterCall( |
| selector.member, callSite.isNullableReceiver); |
| } |
| } |
| } |
| |
| void _annotateMember(Member member) { |
| if (_typeFlowAnalysis.isMemberUsed(member)) { |
| if (member is Field) { |
| _setInferredType(member, _typeFlowAnalysis.fieldType(member)!); |
| } else { |
| Args<Type> argTypes = _typeFlowAnalysis.argumentTypes(member)!; |
| final uncheckedParameters = |
| _typeFlowAnalysis.uncheckedParameters(member); |
| |
| final int firstParamIndex = |
| numTypeParams(member) + (hasReceiverArg(member) ? 1 : 0); |
| |
| final positionalParams = member.function!.positionalParameters; |
| assert(argTypes.positionalCount == |
| firstParamIndex + positionalParams.length); |
| |
| for (int i = 0; i < positionalParams.length; i++) { |
| _setInferredType( |
| positionalParams[i], argTypes.values[firstParamIndex + i], |
| skipCheck: uncheckedParameters!.contains(positionalParams[i])); |
| } |
| |
| // TODO(dartbug.com/32292): make sure parameters are sorted in kernel |
| // AST and iterate parameters in parallel, without lookup. |
| final names = argTypes.names; |
| for (int i = 0; i < names.length; i++) { |
| final param = findNamedParameter(member.function!, names[i])!; |
| _setInferredType(param, |
| argTypes.values[firstParamIndex + positionalParams.length + i], |
| skipCheck: uncheckedParameters!.contains(param)); |
| } |
| |
| // TODO(alexmarkov): figure out how to pass receiver type. |
| } |
| |
| final unboxingInfoMetadata = |
| _unboxingInfo.getUnboxingInfoOfMember(member); |
| if (unboxingInfoMetadata != null && !unboxingInfoMetadata.isFullyBoxed) { |
| _unboxingInfoMetadata.mapping[member] = unboxingInfoMetadata; |
| } |
| } else { |
| if (!member.isAbstract && |
| !fieldMorpher.isExtraMemberWithReachableBody(member)) { |
| _setUnreachable(member); |
| } |
| |
| if (member is! Field) { |
| final unboxingInfoMetadata = |
| _unboxingInfo.getUnboxingInfoOfMember(member); |
| if (unboxingInfoMetadata != null) { |
| // Check for partitions that only have abstract methods should be marked as boxed. |
| if (unboxingInfoMetadata.returnInfo == |
| UnboxingInfoMetadata.kUnboxingCandidate) { |
| unboxingInfoMetadata.returnInfo = UnboxingInfoMetadata.kBoxed; |
| } |
| for (int i = 0; |
| i < unboxingInfoMetadata.unboxedArgsInfo.length; |
| i++) { |
| if (unboxingInfoMetadata.unboxedArgsInfo[i] == |
| UnboxingInfoMetadata.kUnboxingCandidate) { |
| unboxingInfoMetadata.unboxedArgsInfo[i] = |
| UnboxingInfoMetadata.kBoxed; |
| } |
| } |
| if (!unboxingInfoMetadata.isFullyBoxed) { |
| _unboxingInfoMetadata.mapping[member] = unboxingInfoMetadata; |
| } |
| } |
| } |
| } |
| |
| // We need to attach ProcedureAttributesMetadata to all members, even |
| // unreachable ones, since an unreachable member could still be used as an |
| // interface target, and table dispatch calls need selector IDs for all |
| // interface targets. |
| if (member.isInstanceMember) { |
| final original = fieldMorpher.getOriginalMember(member)!; |
| final attrs = new ProcedureAttributesMetadata( |
| methodOrSetterCalledDynamically: |
| _typeFlowAnalysis.isCalledDynamically(original), |
| getterCalledDynamically: |
| _typeFlowAnalysis.isGetterCalledDynamically(original), |
| hasThisUses: _typeFlowAnalysis.isCalledViaThis(original), |
| hasNonThisUses: _typeFlowAnalysis.isCalledNotViaThis(original), |
| hasTearOffUses: _typeFlowAnalysis.isTearOffTaken(original), |
| methodOrSetterSelectorId: |
| _tableSelectorAssigner.methodOrSetterSelectorId(member), |
| getterSelectorId: _tableSelectorAssigner.getterSelectorId(member)); |
| _procedureAttributesMetadata.mapping[member] = attrs; |
| } |
| } |
| |
| @override |
| visitConstructor(Constructor node) { |
| _annotateMember(node); |
| super.visitConstructor(node); |
| } |
| |
| @override |
| visitProcedure(Procedure node) { |
| _annotateMember(node); |
| super.visitProcedure(node); |
| } |
| |
| @override |
| visitField(Field node) { |
| _annotateMember(node); |
| super.visitField(node); |
| } |
| |
| @override |
| visitInstanceInvocation(InstanceInvocation node) { |
| _annotateCallSite(node, node.interfaceTarget); |
| super.visitInstanceInvocation(node); |
| } |
| |
| @override |
| visitDynamicInvocation(DynamicInvocation node) { |
| _annotateCallSite(node, null); |
| super.visitDynamicInvocation(node); |
| } |
| |
| @override |
| visitLocalFunctionInvocation(LocalFunctionInvocation node) { |
| _annotateCallSite(node, null); |
| super.visitLocalFunctionInvocation(node); |
| } |
| |
| @override |
| visitFunctionInvocation(FunctionInvocation node) { |
| _annotateCallSite(node, null); |
| super.visitFunctionInvocation(node); |
| } |
| |
| @override |
| visitEqualsCall(EqualsCall node) { |
| _annotateCallSite(node, null); |
| super.visitEqualsCall(node); |
| } |
| |
| @override |
| visitInstanceGet(InstanceGet node) { |
| _annotateCallSite(node, node.interfaceTarget); |
| super.visitInstanceGet(node); |
| } |
| |
| @override |
| visitInstanceTearOff(InstanceTearOff node) { |
| _annotateCallSite(node, node.interfaceTarget); |
| super.visitInstanceTearOff(node); |
| } |
| |
| @override |
| visitFunctionTearOff(FunctionTearOff node) { |
| _annotateCallSite(node, null); |
| super.visitFunctionTearOff(node); |
| } |
| |
| @override |
| visitDynamicGet(DynamicGet node) { |
| _annotateCallSite(node, null); |
| super.visitDynamicGet(node); |
| } |
| |
| @override |
| visitInstanceSet(InstanceSet node) { |
| _annotateCallSite(node, node.interfaceTarget); |
| super.visitInstanceSet(node); |
| } |
| |
| @override |
| visitDynamicSet(DynamicSet node) { |
| _annotateCallSite(node, null); |
| super.visitDynamicSet(node); |
| } |
| |
| @override |
| visitSuperMethodInvocation(SuperMethodInvocation node) { |
| _annotateCallSite(node, node.interfaceTarget); |
| super.visitSuperMethodInvocation(node); |
| } |
| |
| @override |
| visitSuperPropertyGet(SuperPropertyGet node) { |
| _annotateCallSite(node, node.interfaceTarget); |
| super.visitSuperPropertyGet(node); |
| } |
| |
| @override |
| visitSuperPropertySet(SuperPropertySet node) { |
| _annotateCallSite(node, node.interfaceTarget); |
| super.visitSuperPropertySet(node); |
| } |
| |
| @override |
| visitStaticInvocation(StaticInvocation node) { |
| _annotateCallSite(node, node.target); |
| super.visitStaticInvocation(node); |
| } |
| |
| @override |
| visitStaticGet(StaticGet node) { |
| _annotateCallSite(node, node.target); |
| super.visitStaticGet(node); |
| } |
| |
| @override |
| visitStaticSet(StaticSet node) { |
| _annotateCallSite(node, node.target); |
| super.visitStaticSet(node); |
| } |
| |
| @override |
| visitComponent(Component node) { |
| super.visitComponent(node); |
| _tableSelectorMetadata.mapping[node] = _tableSelectorAssigner.metadata; |
| } |
| } |
| |
| /// Tree shaking based on results of type flow analysis (TFA). |
| /// |
| /// TFA provides information about allocated classes and reachable member |
| /// bodies. However, it is not enough to perform tree shaking in one pass: |
| /// we need to figure out which classes, members and typedefs are used |
| /// in types, interface targets and annotations. |
| /// |
| /// So, tree shaking is performed in 2 passes: |
| /// |
| /// * Pass 1 visits declarations of classes and members, and dives deep into |
| /// bodies of reachable members. It collects sets of used classes, members |
| /// and typedefs. Also, while visiting bodies of reachable members, it |
| /// transforms unreachable calls into 'throw' expressions. |
| /// |
| /// * Pass 2 removes unused classes and members, and replaces bodies of |
| /// used but unreachable members. |
| /// |
| class TreeShaker { |
| final TypeFlowAnalysis typeFlowAnalysis; |
| final bool treeShakeWriteOnlyFields; |
| final Set<Class> _usedClasses = new Set<Class>(); |
| final Set<Class> _classesUsedInType = new Set<Class>(); |
| final Set<Member> _usedMembers = new Set<Member>(); |
| final Set<Extension> _usedExtensions = new Set<Extension>(); |
| final Set<Typedef> _usedTypedefs = new Set<Typedef>(); |
| late final FieldMorpher fieldMorpher; |
| late final _TreeShakerTypeVisitor typeVisitor; |
| late final _TreeShakerConstantVisitor constantVisitor; |
| late final _TreeShakerPass1 _pass1; |
| late final _TreeShakerPass2 _pass2; |
| |
| TreeShaker(Component component, this.typeFlowAnalysis, |
| {this.treeShakeWriteOnlyFields: true}) { |
| fieldMorpher = new FieldMorpher(this); |
| typeVisitor = new _TreeShakerTypeVisitor(this); |
| constantVisitor = new _TreeShakerConstantVisitor(this, typeVisitor); |
| _pass1 = new _TreeShakerPass1(this); |
| _pass2 = new _TreeShakerPass2(this); |
| } |
| |
| transformComponent(Component component) { |
| _pass1.transformComponent(component); |
| _pass2.transformComponent(component); |
| } |
| |
| bool isClassReferencedFromNativeCode(Class c) => |
| typeFlowAnalysis.nativeCodeOracle.isClassReferencedFromNativeCode(c); |
| bool isClassUsed(Class c) => _usedClasses.contains(c); |
| bool isClassUsedInType(Class c) => _classesUsedInType.contains(c); |
| bool isClassAllocated(Class c) => typeFlowAnalysis.isClassAllocated(c); |
| bool isMemberUsed(Member m) => _usedMembers.contains(m); |
| bool isExtensionUsed(Extension e) => _usedExtensions.contains(e); |
| bool isMemberBodyReachable(Member m) => |
| typeFlowAnalysis.isMemberUsed(m) || |
| fieldMorpher.isExtraMemberWithReachableBody(m); |
| bool isFieldInitializerReachable(Field f) => |
| typeFlowAnalysis.isFieldInitializerUsed(f); |
| bool isFieldGetterReachable(Field f) => typeFlowAnalysis.isFieldGetterUsed(f); |
| bool isFieldSetterReachable(Field f) => typeFlowAnalysis.isFieldSetterUsed(f); |
| bool isMemberReferencedFromNativeCode(Member m) => |
| typeFlowAnalysis.nativeCodeOracle.isMemberReferencedFromNativeCode(m); |
| bool isTypedefUsed(Typedef t) => _usedTypedefs.contains(t); |
| |
| bool retainField(Field f) => |
| isMemberBodyReachable(f) && |
| (!treeShakeWriteOnlyFields || |
| isFieldGetterReachable(f) || |
| (!f.isStatic && |
| f.initializer != null && |
| isFieldInitializerReachable(f) && |
| mayHaveSideEffects(f.initializer!)) || |
| (f.isLate && f.isFinal)) || |
| isMemberReferencedFromNativeCode(f) || |
| _isInstanceFieldOfAllocatedEnum(f); |
| |
| /// Preserve instance fields of allocated enums as VM relies on their |
| /// existence. Non-allocated enums are converted into ordinary classes during |
| /// the 2nd pass. |
| bool _isInstanceFieldOfAllocatedEnum(Field node) => |
| !node.isStatic && |
| node.enclosingClass != null && |
| node.enclosingClass!.isEnum && |
| isClassAllocated(node.enclosingClass!); |
| |
| void addClassUsedInType(Class c) { |
| if (_classesUsedInType.add(c)) { |
| if (kPrintDebug) { |
| debugPrint('Class ${c.name} used in type'); |
| } |
| _usedClasses.add(c); |
| visitIterable(c.supers, typeVisitor); |
| _pass1.transformTypeParameterList(c.typeParameters, c); |
| _pass1.transformExpressionList(c.annotations, c); |
| // Preserve NSM forwarders. They are overlooked by TFA / tree shaker |
| // as they are abstract and don't have a body. |
| for (Procedure p in c.procedures) { |
| if (p.isAbstract && p.isNoSuchMethodForwarder) { |
| addUsedMember(p); |
| } |
| } |
| } |
| } |
| |
| void addUsedMember(Member m) { |
| if (_usedMembers.add(m)) { |
| final enclosingClass = m.enclosingClass; |
| if (enclosingClass != null) { |
| if (kPrintDebug) { |
| debugPrint('Member $m from class ${enclosingClass.name} is used'); |
| } |
| _usedClasses.add(enclosingClass); |
| } |
| |
| FunctionNode? func = null; |
| if (m is Field) { |
| m.type.accept(typeVisitor); |
| } else if (m is Procedure) { |
| func = m.function; |
| if (m.concreteForwardingStubTarget != null) { |
| m.stubTarget = fieldMorpher.adjustInstanceCallTarget( |
| m.concreteForwardingStubTarget, |
| isSetter: m.isSetter); |
| addUsedMember(m.concreteForwardingStubTarget!); |
| } |
| if (m.abstractForwardingStubTarget != null) { |
| m.stubTarget = fieldMorpher.adjustInstanceCallTarget( |
| m.abstractForwardingStubTarget, |
| isSetter: m.isSetter); |
| addUsedMember(m.abstractForwardingStubTarget!); |
| } |
| if (m.memberSignatureOrigin != null) { |
| m.stubTarget = fieldMorpher.adjustInstanceCallTarget( |
| m.memberSignatureOrigin, |
| isSetter: m.isSetter); |
| addUsedMember(m.memberSignatureOrigin!); |
| } |
| } else if (m is Constructor) { |
| func = m.function; |
| } else { |
| throw 'Unexpected member ${m.runtimeType}: $m'; |
| } |
| |
| if (func != null) { |
| _pass1.transformTypeParameterList(func.typeParameters, func); |
| addUsedParameters(func.positionalParameters); |
| addUsedParameters(func.namedParameters); |
| func.returnType.accept(typeVisitor); |
| } |
| |
| _pass1.transformExpressionList(m.annotations, m); |
| |
| // If the member is kept alive we need to keep the extension alive. |
| if (m.isExtensionMember) { |
| // The AST should have exactly one [Extension] for [m]. |
| final extension = m.enclosingLibrary.extensions.firstWhere((extension) { |
| return extension.members |
| .any((descriptor) => descriptor.member.asMember == m); |
| }); |
| |
| // Ensure we retain the [Extension] itself (though members might be |
| // shaken) |
| addUsedExtension(extension); |
| } |
| } |
| } |
| |
| void addUsedParameters(List<VariableDeclaration> params) { |
| for (var param in params) { |
| // Do not visit initializer (default value) of a parameter as it is |
| // going to be removed during pass 2. |
| _pass1.transformExpressionList(param.annotations, param); |
| param.type.accept(typeVisitor); |
| } |
| } |
| |
| void addUsedExtension(Extension node) { |
| if (_usedExtensions.add(node)) { |
| node.annotations = const <Expression>[]; |
| _pass1.transformTypeParameterList(node.typeParameters, node); |
| node.onType.accept(typeVisitor); |
| } |
| } |
| |
| void addUsedTypedef(Typedef typedef) { |
| if (_usedTypedefs.add(typedef)) { |
| typedef.annotations = const <Expression>[]; |
| _pass1.transformTypeParameterList(typedef.typeParameters, typedef); |
| _pass1.transformTypeParameterList( |
| typedef.typeParametersOfFunctionType, typedef); |
| _pass1.transformVariableDeclarationList( |
| typedef.positionalParameters, typedef); |
| _pass1.transformVariableDeclarationList(typedef.namedParameters, typedef); |
| typedef.type?.accept(typeVisitor); |
| } |
| } |
| } |
| |
| class FieldMorpher { |
| final TreeShaker shaker; |
| final Set<Member> _extraMembersWithReachableBody = <Member>{}; |
| final Map<Field, Member> _gettersForRemovedFields = <Field, Member>{}; |
| final Map<Field, Member> _settersForRemovedFields = <Field, Member>{}; |
| final Map<Member, Field> _removedFields = <Member, Field>{}; |
| |
| FieldMorpher(this.shaker); |
| |
| Member _createAccessorForRemovedField(Field field, bool isSetter) { |
| assert(!field.isStatic); |
| assert(!shaker.retainField(field)); |
| Procedure accessor; |
| if (isSetter) { |
| final isAbstract = !shaker.isFieldSetterReachable(field); |
| final parameter = new VariableDeclaration('value', type: field.type) |
| ..isCovariantByDeclaration = field.isCovariantByDeclaration |
| ..isCovariantByClass = field.isCovariantByClass |
| ..fileOffset = field.fileOffset; |
| accessor = new Procedure( |
| field.name, |
| ProcedureKind.Setter, |
| new FunctionNode(null, |
| positionalParameters: [parameter], returnType: const VoidType()) |
| ..fileOffset = field.fileOffset, |
| isAbstract: isAbstract, |
| fileUri: field.fileUri); |
| if (!isAbstract) { |
| _extraMembersWithReachableBody.add(accessor); |
| } |
| } else { |
| accessor = new Procedure(field.name, ProcedureKind.Getter, |
| new FunctionNode(null, returnType: field.type), |
| isAbstract: true, fileUri: field.fileUri); |
| } |
| accessor.fileOffset = field.fileOffset; |
| field.enclosingClass!.addProcedure(accessor); |
| _removedFields[accessor] = field; |
| shaker.addUsedMember(accessor); |
| return accessor; |
| } |
| |
| /// Return a replacement for an instance call target. |
| /// If necessary, creates a getter or setter as a replacement if target is a |
| /// field which is going to be removed by the tree shaker. |
| /// This method is used during tree shaker pass 1. |
| Member? adjustInstanceCallTarget(Member? target, {bool isSetter = false}) { |
| if (target is Field && !shaker.retainField(target)) { |
| final targets = |
| isSetter ? _settersForRemovedFields : _gettersForRemovedFields; |
| return targets[target] ??= |
| _createAccessorForRemovedField(target, isSetter); |
| } |
| return target; |
| } |
| |
| bool isExtraMemberWithReachableBody(Member member) => |
| _extraMembersWithReachableBody.contains(member); |
| |
| /// Return a member which replaced [target] in instance calls. |
| /// This method can be used after tree shaking to discover replacement. |
| Member? getMorphedMember(Member? target, {bool isSetter = false}) { |
| if (target is! Field) { |
| return target; |
| } |
| final targets = |
| isSetter ? _settersForRemovedFields : _gettersForRemovedFields; |
| return targets[target] ?? target; |
| } |
| |
| /// Return original member which was replaced by [target] in instance calls. |
| /// This method can be used after tree shaking. |
| Member? getOriginalMember(Member? target) { |
| if (target == null) { |
| return null; |
| } |
| return _removedFields[target] ?? target; |
| } |
| } |
| |
| /// Visits Dart types and collects all classes and typedefs used in types. |
| /// This visitor is used during pass 1 of tree shaking. It is a separate |
| /// visitor because [Transformer] does not provide a way to traverse types. |
| class _TreeShakerTypeVisitor extends RecursiveVisitor { |
| final TreeShaker shaker; |
| |
| _TreeShakerTypeVisitor(this.shaker); |
| |
| @override |
| visitInterfaceType(InterfaceType node) { |
| shaker.addClassUsedInType(node.classNode); |
| node.visitChildren(this); |
| } |
| |
| @override |
| visitSupertype(Supertype node) { |
| shaker.addClassUsedInType(node.classNode); |
| node.visitChildren(this); |
| } |
| |
| @override |
| visitTypedefType(TypedefType node) { |
| shaker.addUsedTypedef(node.typedefNode); |
| node.visitChildren(this); |
| } |
| |
| @override |
| visitFunctionType(FunctionType node) { |
| node.visitChildren(this); |
| final typedef = node.typedef; |
| if (typedef != null) { |
| shaker.addUsedTypedef(typedef); |
| } |
| } |
| |
| @override |
| visitTypeParameterType(TypeParameterType node) { |
| final parent = node.parameter.parent; |
| if (parent is Class) { |
| shaker.addClassUsedInType(parent); |
| } |
| } |
| } |
| |
| /// The first pass of [TreeShaker]. |
| /// Visits all classes, members and bodies of reachable members. |
| /// Collects all used classes, members and types, and |
| /// transforms unreachable calls into 'throw' expressions. |
| class _TreeShakerPass1 extends RemovingTransformer { |
| final TreeShaker shaker; |
| final FieldMorpher fieldMorpher; |
| final TypeEnvironment environment; |
| |
| StaticTypeContext? _staticTypeContext; |
| Member? _currentMember; |
| |
| StaticTypeContext get staticTypeContext => |
| _staticTypeContext ??= StaticTypeContext(currentMember, environment); |
| |
| Member get currentMember => _currentMember!; |
| set currentMember(Member? m) { |
| _currentMember = m; |
| _staticTypeContext = null; |
| } |
| |
| _TreeShakerPass1(this.shaker) |
| : fieldMorpher = shaker.fieldMorpher, |
| environment = shaker.typeFlowAnalysis.environment; |
| |
| void transformComponent(Component component) { |
| component.transformOrRemoveChildren(this); |
| } |
| |
| bool _isUnreachable(TreeNode node) { |
| final callSite = shaker.typeFlowAnalysis.callSite(node); |
| return (callSite != null) && !callSite.isReachable; |
| } |
| |
| List<Expression> _flattenArguments(Arguments arguments, |
| {Expression? receiver}) { |
| final args = <Expression>[]; |
| if (receiver != null) { |
| args.add(receiver); |
| } |
| args.addAll(arguments.positional); |
| args.addAll(arguments.named.map((a) => a.value)); |
| return args; |
| } |
| |
| bool _isThrowExpression(Expression expr) { |
| for (;;) { |
| if (expr is Let) { |
| expr = expr.body; |
| } else if (expr is BlockExpression) { |
| expr = expr.value; |
| } else { |
| break; |
| } |
| } |
| return expr is Throw; |
| } |
| |
| Expression _evaluateArguments(List<Expression> args, Expression result) { |
| final List<ast.Statement> statements = <ast.Statement>[]; |
| for (var arg in args) { |
| if (mayHaveSideEffects(arg)) { |
| if (arg is BlockExpression && !mayHaveSideEffects(arg.value)) { |
| statements.add(arg.body); |
| } else { |
| statements.add(ExpressionStatement(arg)); |
| } |
| } |
| } |
| if (statements.isEmpty) { |
| return result; |
| } |
| // Merge nested BlockExpression nodes. |
| Expression value = result; |
| if (result is BlockExpression) { |
| statements.addAll(result.body.statements); |
| value = result.value; |
| } |
| return BlockExpression(Block(statements), value); |
| } |
| |
| Expression _makeUnreachableCall(List<Expression> args) { |
| Expression node; |
| final int last = args.indexWhere(_isThrowExpression); |
| if (last >= 0) { |
| // One of the arguments is a Throw expression. |
| // Ignore the rest of the arguments. |
| node = args[last]; |
| args = args.sublist(0, last); |
| Statistics.throwExpressionsPruned++; |
| } else { |
| node = Throw(StringLiteral( |
| 'Attempt to execute code removed by Dart AOT compiler (TFA)')); |
| } |
| Statistics.callsDropped++; |
| return _evaluateArguments(args, node); |
| } |
| |
| TreeNode _makeUnreachableInitializer(List<Expression> args) { |
| return new LocalInitializer( |
| new VariableDeclaration(null, initializer: _makeUnreachableCall(args))); |
| } |
| |
| NarrowNotNull? _getNullTest(TreeNode node) => |
| shaker.typeFlowAnalysis.nullTest(node); |
| |
| TreeNode _visitAssertNode(TreeNode node, TreeNode? removalSentinel) { |
| if (kRemoveAsserts) { |
| return removalSentinel!; |
| } else { |
| node.transformOrRemoveChildren(this); |
| return node; |
| } |
| } |
| |
| @override |
| DartType visitDartType(DartType node, DartType? removalSentinel) { |
| node.accept(shaker.typeVisitor); |
| return node; |
| } |
| |
| @override |
| Supertype visitSupertype(Supertype node, Supertype? removalSentinel) { |
| node.accept(shaker.typeVisitor); |
| return node; |
| } |
| |
| @override |
| TreeNode visitTypedef(Typedef node, TreeNode? removalSentinel) { |
| return node; // Do not go deeper. |
| } |
| |
| @override |
| TreeNode visitExtension(Extension node, TreeNode? removalSentinel) { |
| // The extension can be considered a weak node, we'll only retain it if |
| // normal code references any of it's members. |
| return node; |
| } |
| |
| @override |
| TreeNode visitClass(Class node, TreeNode? removalSentinel) { |
| if (shaker.isClassAllocated(node) || |
| shaker.isClassReferencedFromNativeCode(node)) { |
| shaker.addClassUsedInType(node); |
| } |
| transformConstructorList(node.constructors, node); |
| transformProcedureList(node.procedures, node); |
| transformFieldList(node.fields, node); |
| transformRedirectingFactoryList(node.redirectingFactories, node); |
| return node; |
| } |
| |
| @override |
| TreeNode defaultMember(Member node, TreeNode? removalSentinel) { |
| currentMember = node; |
| if (shaker.isMemberBodyReachable(node)) { |
| if (kPrintTrace) { |
| tracePrint("Visiting $node"); |
| } |
| shaker.addUsedMember(node); |
| node.transformOrRemoveChildren(this); |
| } else if (shaker.isMemberReferencedFromNativeCode(node)) { |
| // Preserve members referenced from native code to satisfy lookups, even |
| // if they are not reachable. An instance member could be added via |
| // native code entry point but still unreachable if no instances of |
| // its enclosing class are allocated. |
| shaker.addUsedMember(node); |
| } |
| currentMember = null; |
| return node; |
| } |
| |
| @override |
| TreeNode visitField(Field node, TreeNode? removalSentinel) { |
| currentMember = node; |
| if (shaker.retainField(node)) { |
| if (kPrintTrace) { |
| tracePrint("Visiting $node"); |
| } |
| shaker.addUsedMember(node); |
| if (node.initializer != null) { |
| if (shaker.isFieldInitializerReachable(node)) { |
| node.transformOrRemoveChildren(this); |
| } else { |
| node.initializer = _makeUnreachableCall([])..parent = node; |
| } |
| } |
| } else if (shaker.isFieldSetterReachable(node) && !node.isStatic) { |
| // Make sure setter is created to replace the field even if field is not |
| // used as an instance call target. |
| fieldMorpher.adjustInstanceCallTarget(node, isSetter: true); |
| } |
| currentMember = null; |
| return node; |
| } |
| |
| @override |
| TreeNode visitInstanceInvocation( |
| InstanceInvocation node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall( |
| _flattenArguments(node.arguments, receiver: node.receiver)); |
| } |
| node.interfaceTarget = fieldMorpher |
| .adjustInstanceCallTarget(node.interfaceTarget) as Procedure; |
| shaker.addUsedMember(node.interfaceTarget); |
| return node; |
| } |
| |
| @override |
| TreeNode visitDynamicInvocation( |
| DynamicInvocation node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall( |
| _flattenArguments(node.arguments, receiver: node.receiver)); |
| } |
| return node; |
| } |
| |
| @override |
| TreeNode visitLocalFunctionInvocation( |
| LocalFunctionInvocation node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall(_flattenArguments(node.arguments)); |
| } |
| return node; |
| } |
| |
| @override |
| TreeNode visitFunctionInvocation( |
| FunctionInvocation node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall( |
| _flattenArguments(node.arguments, receiver: node.receiver)); |
| } |
| return node; |
| } |
| |
| @override |
| TreeNode visitEqualsCall(EqualsCall node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.left, node.right]); |
| } |
| node.interfaceTarget = fieldMorpher |
| .adjustInstanceCallTarget(node.interfaceTarget) as Procedure; |
| shaker.addUsedMember(node.interfaceTarget); |
| return node; |
| } |
| |
| @override |
| TreeNode visitEqualsNull(EqualsNull node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.expression]); |
| } |
| final nullTest = _getNullTest(node)!; |
| if (nullTest.isAlwaysNull || nullTest.isAlwaysNotNull) { |
| return _evaluateArguments([node.expression], |
| BoolLiteral(nullTest.isAlwaysNull)..fileOffset = node.fileOffset); |
| } |
| return node; |
| } |
| |
| @override |
| TreeNode visitInstanceGet(InstanceGet node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.receiver]); |
| } else { |
| node.interfaceTarget = |
| fieldMorpher.adjustInstanceCallTarget(node.interfaceTarget)!; |
| shaker.addUsedMember(node.interfaceTarget); |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitInstanceTearOff( |
| InstanceTearOff node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.receiver]); |
| } else { |
| node.interfaceTarget = fieldMorpher |
| .adjustInstanceCallTarget(node.interfaceTarget) as Procedure; |
| shaker.addUsedMember(node.interfaceTarget); |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitDynamicGet(DynamicGet node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.receiver]); |
| } else { |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitFunctionTearOff( |
| FunctionTearOff node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.receiver]); |
| } else { |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitInstanceSet(InstanceSet node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.receiver, node.value]); |
| } else { |
| node.interfaceTarget = fieldMorpher |
| .adjustInstanceCallTarget(node.interfaceTarget, isSetter: true)!; |
| shaker.addUsedMember(node.interfaceTarget); |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitDynamicSet(DynamicSet node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.receiver, node.value]); |
| } else { |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitSuperMethodInvocation( |
| SuperMethodInvocation node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall(_flattenArguments(node.arguments)); |
| } else { |
| node.interfaceTarget = fieldMorpher |
| .adjustInstanceCallTarget(node.interfaceTarget) as Procedure?; |
| if (node.interfaceTarget != null) { |
| shaker.addUsedMember(node.interfaceTarget!); |
| } |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitSuperPropertyGet( |
| SuperPropertyGet node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([]); |
| } else { |
| node.interfaceTarget = |
| fieldMorpher.adjustInstanceCallTarget(node.interfaceTarget); |
| if (node.interfaceTarget != null) { |
| shaker.addUsedMember(node.interfaceTarget!); |
| } |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitSuperPropertySet( |
| SuperPropertySet node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.value]); |
| } else { |
| node.interfaceTarget = fieldMorpher |
| .adjustInstanceCallTarget(node.interfaceTarget, isSetter: true); |
| if (node.interfaceTarget != null) { |
| shaker.addUsedMember(node.interfaceTarget!); |
| } |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitStaticInvocation( |
| StaticInvocation node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall(_flattenArguments(node.arguments)); |
| } |
| |
| final target = node.target; |
| assert(shaker.isMemberBodyReachable(target), |
| "Member body is not reachable: $target"); |
| |
| return node; |
| } |
| |
| @override |
| TreeNode visitStaticGet(StaticGet node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([]); |
| } else { |
| if (!shaker.isMemberBodyReachable(node.target)) { |
| throw '${node.runtimeType} "$node" uses unreachable member ' |
| '${node.target} at ${node.location}'; |
| } |
| return node; |
| } |
| } |
| |
| @override |
| Constant visitConstant(Constant node, Constant? removalSentinel) { |
| shaker.constantVisitor.analyzeConstant(node); |
| return node; |
| } |
| |
| @override |
| TreeNode visitStaticSet(StaticSet node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall([node.value]); |
| } else { |
| final target = node.target; |
| assert(shaker.isMemberBodyReachable(target), |
| "Target should be reachable: $node"); |
| if (target is Field && !shaker.retainField(target)) { |
| return node.value; |
| } |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitConstructorInvocation( |
| ConstructorInvocation node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableCall(_flattenArguments(node.arguments)); |
| } else { |
| if (!shaker.isMemberBodyReachable(node.target)) { |
| throw '${node.runtimeType} "$node" uses unreachable member ' |
| '${node.target} at ${node.location}'; |
| } |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitRedirectingInitializer( |
| RedirectingInitializer node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableInitializer(_flattenArguments(node.arguments)); |
| } else { |
| assert(shaker.isMemberBodyReachable(node.target), |
| "Target should be reachable: ${node.target}"); |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitSuperInitializer( |
| SuperInitializer node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableInitializer(_flattenArguments(node.arguments)); |
| } else { |
| // Can't assert that node.target is used due to partial mixin resolution. |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitFieldInitializer( |
| FieldInitializer node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| if (_isUnreachable(node)) { |
| return _makeUnreachableInitializer([node.value]); |
| } else { |
| final field = node.field; |
| assert(shaker.isMemberBodyReachable(field), |
| "Field should be reachable: ${field}"); |
| if (!shaker.retainField(field)) { |
| if (mayHaveSideEffects(node.value)) { |
| return LocalInitializer( |
| VariableDeclaration(null, initializer: node.value)); |
| } else { |
| return removalSentinel!; |
| } |
| } |
| return node; |
| } |
| } |
| |
| @override |
| TreeNode visitAssertStatement( |
| AssertStatement node, TreeNode? removalSentinel) { |
| return _visitAssertNode(node, removalSentinel); |
| } |
| |
| @override |
| TreeNode visitAssertBlock(AssertBlock node, TreeNode? removalSentinel) { |
| return _visitAssertNode(node, removalSentinel); |
| } |
| |
| @override |
| TreeNode visitAssertInitializer( |
| AssertInitializer node, TreeNode? removalSentinel) { |
| return _visitAssertNode(node, removalSentinel); |
| } |
| |
| // Expression is an extended bool literal if it is |
| // - a BoolLiteral |
| // - a BlockExpression with a BoolLiteral value. |
| bool _isExtendedBoolLiteral(Expression expr) => |
| expr is BoolLiteral || |
| (expr is BlockExpression && expr.value is BoolLiteral); |
| |
| // Returns value of an extended bool literal. |
| bool _getExtendedBoolLiteralValue(Expression expr) => (expr is BoolLiteral) |
| ? expr.value |
| : ((expr as BlockExpression).value as BoolLiteral).value; |
| |
| // Returns Block corresponding to the given extended bool literal, |
| // or null if the expression is a simple bool literal. |
| Block? _getExtendedBoolLiteralBlock(Expression expr) => |
| (expr is BoolLiteral) ? null : (expr as BlockExpression).body; |
| |
| @override |
| TreeNode visitIfStatement(IfStatement node, TreeNode? removalSentinel) { |
| final condition = transform(node.condition); |
| if (_isExtendedBoolLiteral(condition)) { |
| final bool conditionValue = _getExtendedBoolLiteralValue(condition); |
| final Block? conditionBlock = _getExtendedBoolLiteralBlock(condition); |
| ast.Statement? body; |
| if (conditionValue) { |
| body = transform(node.then); |
| } else { |
| if (node.otherwise != null) { |
| body = transformOrRemoveStatement(node.otherwise!); |
| } |
| } |
| if (conditionBlock != null) { |
| if (body != null) { |
| conditionBlock.addStatement(body); |
| } |
| return conditionBlock; |
| } else { |
| return body ?? EmptyStatement(); |
| } |
| } |
| node.condition = condition..parent = node; |
| node.then = transform(node.then)..parent = node; |
| if (node.otherwise != null) { |
| node.otherwise = transformOrRemoveStatement(node.otherwise!); |
| node.otherwise?.parent = node; |
| } |
| return node; |
| } |
| |
| @override |
| visitConditionalExpression( |
| ConditionalExpression node, TreeNode? removalSentinel) { |
| final condition = transform(node.condition); |
| if (_isExtendedBoolLiteral(condition)) { |
| final bool value = _getExtendedBoolLiteralValue(condition); |
| final Expression expr = transform(value ? node.then : node.otherwise); |
| if (condition is BlockExpression) { |
| condition.value = expr; |
| expr.parent = condition; |
| return condition; |
| } else { |
| return expr; |
| } |
| } |
| node.condition = condition..parent = node; |
| node.then = transform(node.then)..parent = node; |
| node.otherwise = transform(node.otherwise)..parent = node; |
| node.staticType = visitDartType(node.staticType, cannotRemoveSentinel); |
| return node; |
| } |
| |
| @override |
| TreeNode visitNot(Not node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| final operand = node.operand; |
| if (_isExtendedBoolLiteral(operand)) { |
| final bool value = _getExtendedBoolLiteralValue(operand); |
| if (operand is BlockExpression) { |
| (operand.value as BoolLiteral).value = !value; |
| } else { |
| (operand as BoolLiteral).value = !value; |
| } |
| return operand; |
| } |
| return node; |
| } |
| |
| @override |
| TreeNode visitLogicalExpression( |
| LogicalExpression node, TreeNode? removalSentinel) { |
| final left = transform(node.left); |
| final operatorEnum = node.operatorEnum; |
| if (_isExtendedBoolLiteral(left)) { |
| final leftValue = _getExtendedBoolLiteralValue(left); |
| if (leftValue && operatorEnum == LogicalExpressionOperator.OR) { |
| return left; |
| } else if (!leftValue && operatorEnum == LogicalExpressionOperator.AND) { |
| return left; |
| } |
| } |
| final right = transform(node.right); |
| // Without sound null safety arguments of logical expression |
| // are implicitly checked for null, so transform the node only |
| // if using sound null safety or it evaluates to a bool literal. |
| if (_isExtendedBoolLiteral(left) && |
| (shaker.typeFlowAnalysis.target.flags.enableNullSafety || |
| _isExtendedBoolLiteral(right))) { |
| return _evaluateArguments([left], right); |
| } |
| node.left = left..parent = node; |
| node.right = right..parent = node; |
| return node; |
| } |
| |
| @override |
| TreeNode visitIsExpression(IsExpression node, TreeNode? removalSentinel) { |
| TypeCheck? check = shaker.typeFlowAnalysis.isTest(node); |
| if (check != null && (check.alwaysFail || check.alwaysPass)) { |
| final operand = transform(node.operand); |
| final result = BoolLiteral(!check.alwaysFail) |
| ..fileOffset = node.fileOffset; |
| return _evaluateArguments([operand], result); |
| } |
| node.transformOrRemoveChildren(this); |
| return node; |
| } |
| |
| @override |
| TreeNode visitAsExpression(AsExpression node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| TypeCheck? check = shaker.typeFlowAnalysis.explicitCast(node); |
| if (check != null && check.alwaysPass) { |
| return StaticInvocation( |
| unsafeCast, Arguments([node.operand], types: [node.type])) |
| ..fileOffset = node.fileOffset; |
| } |
| return node; |
| } |
| |
| @override |
| TreeNode visitNullCheck(NullCheck node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| final nullTest = _getNullTest(node)!; |
| if (nullTest.isAlwaysNotNull) { |
| return StaticInvocation( |
| unsafeCast, |
| Arguments([node.operand], |
| types: [node.getStaticType(staticTypeContext)])) |
| ..fileOffset = node.fileOffset; |
| } |
| return node; |
| } |
| |
| late final Procedure unsafeCast = shaker |
| .typeFlowAnalysis.environment.coreTypes.index |
| .getTopLevelProcedure('dart:_internal', 'unsafeCast'); |
| } |
| |
| /// The second pass of [TreeShaker]. It is called after set of used |
| /// classes, members and typedefs is determined during the first pass. |
| /// This pass visits classes and members and removes unused classes and members. |
| /// Bodies of unreachable but used members are replaced with 'throw' |
| /// expressions. This pass does not dive deeper than member level. |
| class _TreeShakerPass2 extends RemovingTransformer { |
| final TreeShaker shaker; |
| |
| _TreeShakerPass2(this.shaker); |
| |
| void transformComponent(Component component) { |
| component.transformOrRemoveChildren(this); |
| for (Source source in component.uriToSource.values) { |
| source.constantCoverageConstructors?.removeWhere((Reference reference) { |
| Member node = reference.asMember; |
| return !shaker.isMemberUsed(node); |
| }); |
| } |
| } |
| |
| @override |
| TreeNode visitLibrary(Library node, TreeNode? removalSentinel) { |
| node.transformOrRemoveChildren(this); |
| // The transformer API does not iterate over `Library.additionalExports`, |
| // so we manually delete the references to shaken nodes. |
| node.additionalExports.removeWhere((Reference reference) { |
| final node = reference.node; |
| if (node is Class) { |
| return !shaker.isClassUsed(node); |
| } else if (node is Typedef) { |
| return !shaker.isTypedefUsed(node); |
| } else if (node is Extension) { |
| return !shaker.isExtensionUsed(node); |
| } else { |
| return !shaker.isMemberUsed(node as Member); |
| } |
| }); |
| return node; |
| } |
| |
| @override |
| TreeNode visitTypedef(Typedef node, TreeNode? removalSentinel) { |
| return shaker.isTypedefUsed(node) ? node : removalSentinel!; |
| } |
| |
| @override |
| TreeNode visitClass(Class node, TreeNode? removalSentinel) { |
| if (!shaker.isClassUsed(node)) { |
| debugPrint('Dropped class ${node.name}'); |
| // Ensure that kernel file writer will not be able to |
| // write a dangling reference to the deleted class. |
| assert( |
| node.reference.node == node, |
| "Trying to remove canonical name from reference on $node which has " |
| "been repurposed for ${node.reference.node}."); |
| node.reference.canonicalName?.unbind(); |
| Statistics.classesDropped++; |
| return removalSentinel!; // Remove the class. |
| } |
| |
| if (!shaker.isClassUsedInType(node)) { |
| debugPrint('Dropped supers from class ${node.name}'); |
| // The class is only a namespace for static members. Remove its |
| // hierarchy information. This is mandatory, since these references |
| // might otherwise become dangling. |
| node.supertype = shaker |
| .typeFlowAnalysis.environment.coreTypes.objectClass.asRawSupertype; |
| node.implementedTypes.clear(); |
| node.typeParameters.clear(); |
| node.isAbstract = true; |
| node.isEnum = false; |
| // Mixin applications cannot have static members. |
| assert(node.mixedInType == null); |
| node.annotations = const <Expression>[]; |
| } |
| |
| if (!shaker.isClassAllocated(node)) { |
| debugPrint('Class ${node.name} converted to abstract'); |
| node.isAbstract = true; |
| node.isEnum = false; |
| } |
| |
| node.transformOrRemoveChildren(this); |
| |
| return node; |
| } |
| |
| @override |
| TreeNode defaultMember(Member node, TreeNode? removalSentinel) { |
| if (!shaker.isMemberUsed(node)) { |
| // Ensure that kernel file writer will not be able to |
| // write a dangling reference to the deleted member. |
| if (node is Field) { |
| assert( |
| node.fieldReference.node == node, |
| "Trying to remove canonical name from field reference on $node " |
| "which has been repurposed for ${node.fieldReference.node}."); |
| node.fieldReference.canonicalName?.unbind(); |
| assert( |
| node.getterReference.node == node, |
| "Trying to remove canonical name from getter reference on $node " |
| "which has been repurposed for ${node.getterReference.node}."); |
| node.getterReference.canonicalName?.unbind(); |
| if (node.hasSetter) { |
| assert( |
| node.setterReference!.node == node, |
| "Trying to remove canonical name from reference on $node which " |
| "has been repurposed for ${node.setterReference!.node}."); |
| node.setterReference!.canonicalName?.unbind(); |
| } |
| } else { |
| assert( |
| node.reference.node == node, |
| "Trying to remove canonical name from reference on $node which has " |
| "been repurposed for ${node.reference.node}."); |
| node.reference.canonicalName?.unbind(); |
| } |
| Statistics.membersDropped++; |
| return removalSentinel!; |
| } |
| |
| if (!shaker.isMemberBodyReachable(node)) { |
| if (node is Procedure) { |
| // Remove body of unused member. |
| if (!node.isStatic && node.enclosingClass!.isAbstract) { |
| node.isAbstract = true; |
| node.function.body = null; |
| } else { |
| // If the enclosing class is not abstract, the method should still |
| // have a body even if it can never be called. |
| _makeUnreachableBody(node.function); |
| } |
| _removeDefaultValuesOfParameters(node.function); |
| node.function.asyncMarker = AsyncMarker.Sync; |
| switch (node.stubKind) { |
| case ProcedureStubKind.Regular: |
| case ProcedureStubKind.NoSuchMethodForwarder: |
| break; |
| case ProcedureStubKind.MemberSignature: |
| case ProcedureStubKind.AbstractForwardingStub: |
| case ProcedureStubKind.ConcreteForwardingStub: |
| case ProcedureStubKind.AbstractMixinStub: |
| case ProcedureStubKind.ConcreteMixinStub: |
| // Make the stub look like a regular procedure so the stub target |
| // isn't expected to be non-null, for instance by the verifier. |
| node.stubKind = ProcedureStubKind.Regular; |
| node.stubTarget = null; |
| break; |
| } |
| Statistics.methodBodiesDropped++; |
| } else if (node is Field) { |
| node.initializer = null; |
| Statistics.fieldInitializersDropped++; |
| } else if (node is Constructor) { |
| _makeUnreachableBody(node.function); |
| _removeDefaultValuesOfParameters(node.function); |
| node.initializers = const <Initializer>[]; |
| Statistics.constructorBodiesDropped++; |
| } else { |
| throw 'Unexpected member ${node.runtimeType}: $node'; |
| } |
| } |
| |
| return node; |
| } |
| |
| @override |
| TreeNode visitExtension(Extension node, TreeNode? removalSentinel) { |
| if (shaker.isExtensionUsed(node)) { |
| int writeIndex = 0; |
| for (int i = 0; i < node.members.length; ++i) { |
| final ExtensionMemberDescriptor descriptor = node.members[i]; |
| |
| // To avoid depending on the order in which members and extensions are |
| // visited during the transformation, we handle both cases: either the |
| // member was already removed or it will be removed later. |
| final Reference memberReference = descriptor.member; |
| final bool isBound = memberReference.node != null; |
| if (isBound && shaker.isMemberUsed(memberReference.asMember)) { |
| node.members[writeIndex++] = descriptor; |
| } |
| } |
| node.members.length = writeIndex; |
| |
| // We only retain the extension if at least one member is retained. |
| assert(node.members.length > 0); |
| return node; |
| } |
| return removalSentinel!; |
| } |
| |
| void _makeUnreachableBody(FunctionNode function) { |
| if (function.body != null) { |
| function.body = new ExpressionStatement(new Throw(new StringLiteral( |
| "Attempt to execute method removed by Dart AOT compiler (TFA)"))) |
| ..parent = function; |
| } |
| } |
| |
| void _removeDefaultValuesOfParameters(FunctionNode function) { |
| for (var p in function.positionalParameters) { |
| p.initializer = null; |
| } |
| for (var p in function.namedParameters) { |
| p.initializer = null; |
| } |
| } |
| |
| @override |
| TreeNode defaultTreeNode(TreeNode node, TreeNode? removalSentinel) { |
| return node; // Do not traverse into other nodes. |
| } |
| } |
| |
| class _TreeShakerConstantVisitor extends ConstantVisitor<Null> { |
| final TreeShaker shaker; |
| final _TreeShakerTypeVisitor typeVisitor; |
| final Set<Constant> constants = new Set<Constant>(); |
| final Set<InstanceConstant> instanceConstants = new Set<InstanceConstant>(); |
| |
| _TreeShakerConstantVisitor(this.shaker, this.typeVisitor); |
| |
| analyzeConstant(Constant constant) { |
| if (constants.add(constant)) { |
| constant.accept(this); |
| } |
| } |
| |
| @override |
| defaultConstant(Constant constant) { |
| throw 'There is no support for constant "$constant" in TFA yet!'; |
| } |
| |
| @override |
| visitNullConstant(NullConstant constant) {} |
| |
| @override |
| visitBoolConstant(BoolConstant constant) {} |
| |
| @override |
| visitIntConstant(IntConstant constant) {} |
| |
| @override |
| visitDoubleConstant(DoubleConstant constant) {} |
| |
| @override |
| visitSetConstant(SetConstant constant) { |
| for (final entry in constant.entries) { |
| analyzeConstant(entry); |
| } |
| } |
| |
| @override |
| visitStringConstant(StringConstant constant) {} |
| |
| @override |
| visitSymbolConstant(SymbolConstant constant) { |
| // The Symbol class and it's _name field are always retained. |
| } |
| |
| @override |
| visitMapConstant(MapConstant constant) { |
| for (final entry in constant.entries) { |
| analyzeConstant(entry.key); |
| analyzeConstant(entry.value); |
| } |
| } |
| |
| @override |
| visitListConstant(ListConstant constant) { |
| for (final Constant entry in constant.entries) { |
| analyzeConstant(entry); |
| } |
| } |
| |
| @override |
| visitInstanceConstant(InstanceConstant constant) { |
| instanceConstants.add(constant); |
| shaker.addClassUsedInType(constant.classNode); |
| visitList(constant.typeArguments, typeVisitor); |
| constant.fieldValues.forEach((Reference fieldRef, Constant value) { |
| if (!shaker.retainField(fieldRef.asField)) { |
| throw 'Constant $constant references field ${fieldRef.asField} ' |
| 'which is not retained'; |
| } |
| analyzeConstant(value); |
| }); |
| } |
| |
| @override |
| visitStaticTearOffConstant(StaticTearOffConstant constant) { |
| shaker.addUsedMember(constant.target); |
| } |
| |
| @override |
| visitConstructorTearOffConstant(ConstructorTearOffConstant constant) { |
| shaker.addUsedMember(constant.target); |
| } |
| |
| @override |
| visitRedirectingFactoryTearOffConstant( |
| RedirectingFactoryTearOffConstant constant) { |
| shaker.addUsedMember(constant.target); |
| } |
| |
| @override |
| visitInstantiationConstant(InstantiationConstant constant) { |
| analyzeConstant(constant.tearOffConstant); |
| } |
| |
| @override |
| visitTypeLiteralConstant(TypeLiteralConstant constant) { |
| constant.type.accept(typeVisitor); |
| } |
| } |
