pkg/compiler/lib/src/universe/codegen_world_builder.dart

// 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.

import 'dart:collection';

import '../common.dart';
import '../common/elements.dart';
import '../common/names.dart' show Identifiers;
import '../constants/values.dart';
import '../elements/entities.dart';
import '../elements/types.dart';
import '../js_backend/annotations.dart' show AnnotationsData;
import '../js_backend/inferred_data.dart';
import '../js_backend/interceptor_data.dart' show OneShotInterceptorData;
import '../js_backend/native_data.dart' show NativeBasicData;
import '../js_model/elements.dart';
import '../js_model/js_world.dart' show JClosedWorld;
import '../universe/class_hierarchy.dart';
import '../util/enumset.dart';
import '../util/util.dart';
import '../world.dart';
import 'call_structure.dart';
import 'member_usage.dart';
import 'selector.dart' show Selector;
import 'use.dart'
    show ConstantUse, DynamicUse, DynamicUseKind, StaticUse, StaticUseKind;
import 'world_builder.dart';

// The immutable result of the [CodegenWorldBuilder].
abstract class CodegenWorld extends BuiltWorld {
  /// Returns `true` if [member] is a late member visited by the codegen
  /// enqueuer and is therefore reachable within the program. After
  /// serialization all late members are registered in the closed world. This
  /// predicate is used to determine which of these members are actually used.
  bool isLateMemberReachable(MemberEntity member);

  /// Calls [f] for each generic call method on a live closure class.
  void forEachGenericClosureCallMethod(void Function(FunctionEntity) f);

  bool hasInvokedGetter(MemberEntity member);

  /// Returns `true` if [member] is invoked as a setter.
  bool hasInvokedSetter(MemberEntity member);

  Map<Selector, SelectorConstraints>? invocationsByName(String name);

  Iterable<Selector>? getterInvocationsByName(String name);

  Iterable<Selector>? setterInvocationsByName(String name);

  void forEachInvokedName(
    void Function(String name, Map<Selector, SelectorConstraints> selectors) f,
  );

  void forEachInvokedGetter(
    void Function(String name, Map<Selector, SelectorConstraints> selectors) f,
  );

  void forEachInvokedSetter(
    void Function(String name, Map<Selector, SelectorConstraints> selectors) f,
  );

  /// All directly instantiated classes, that is, classes with a generative
  /// constructor that has been called directly and not only through a
  /// super-call.
  // TODO(johnniwinther): Improve semantic precision.
  Iterable<ClassEntity> get directlyInstantiatedClasses;

  Iterable<ClassEntity> get constructorReferences;

  /// All directly or indirectly instantiated classes.
  Iterable<ClassEntity> get instantiatedClasses;

  bool methodsNeedsSuperGetter(FunctionEntity function);

  /// The calls [f] for all static fields.
  void forEachStaticField(void Function(FieldEntity) f);

  /// Returns the types that are live as constant type literals.
  Iterable<DartType> get constTypeLiterals;

  /// Returns the types that are live as constant type arguments.
  Iterable<DartType> get liveTypeArguments;

  /// Returns a list of constants topologically sorted so that dependencies
  /// appear before the dependent constant.
  ///
  /// [preSortCompare] is a comparator function that gives the constants a
  /// consistent order prior to the topological sort which gives the constants
  /// an ordering that is less sensitive to perturbations in the source code.
  Iterable<ConstantValue> getConstantsForEmission([
    Comparator<ConstantValue>? preSortCompare,
  ]);

  /// Returns `true` if [member] is called from a subclass via `super`.
  bool isAliasedSuperMember(MemberEntity member);

  OneShotInterceptorData get oneShotInterceptorData;

  Iterable<JParameterStub> getParameterStubs(FunctionEntity function);
}

class CodegenWorldBuilder extends WorldBuilder {
  final JClosedWorld _closedWorld;
  final InferredData _inferredData;
  final OneShotInterceptorData _oneShotInterceptorData;

  /// All declaration elements that have been processed by codegen.
  final Set<MemberEntity> processedEntities = {};

  /// The set of all directly instantiated classes, that is, classes with a
  /// generative constructor that has been called directly and not only through
  /// a super-call.
  ///
  /// Invariant: Elements are declaration elements.
  // TODO(johnniwinther): [_directlyInstantiatedClasses] and
  // [_instantiatedTypes] sets should be merged.
  final Set<ClassEntity> _directlyInstantiatedClasses = {};

  /// The set of all directly instantiated types, that is, the types of the
  /// directly instantiated classes.
  ///
  /// See [_directlyInstantiatedClasses].
  final Set<InterfaceType> _instantiatedTypes = {};

  /// Classes implemented by directly instantiated classes.
  final Set<ClassEntity> _implementedClasses = {};

  final Map<String, Map<Selector, SelectorConstraints>> _invokedNames = {};
  final Map<String, Map<Selector, SelectorConstraints>> _invokedGetters = {};
  final Map<String, Map<Selector, SelectorConstraints>> _invokedSetters = {};

  final Map<ClassEntity, ClassUsage> _processedClasses = {};

  Map<ClassEntity, ClassUsage> get classUsageForTesting => _processedClasses;

  /// Map of registered usage of static and instance members.
  final Map<MemberEntity, MemberUsage> _memberUsage = {};

  /// Map containing instance members of live classes that have not yet been
  /// fully invoked dynamically.
  ///
  /// A method is fully invoked if all is optional parameter have been passed
  /// in some invocation.
  final Map<String, Set<MemberUsage>> _invokableInstanceMembersByName = {};

  /// Map containing instance members of live classes that have not yet been
  /// read from dynamically.
  final Map<String, Set<MemberUsage>> _readableInstanceMembersByName = {};

  /// Map containing instance members of live classes that have not yet been
  /// written to dynamically.
  final Map<String, Set<MemberUsage>> _writableInstanceMembersByName = {};

  final Set<DartType> _isChecks = {};

  final SelectorConstraintsStrategy _selectorConstraintsStrategy;

  final Set<ConstantValue> _constantValues = {};

  final Set<DartType> _constTypeLiterals = {};
  final Set<DartType> _liveTypeArguments = {};
  final Set<TypeVariableType> _namedTypeVariables = {};
  final Set<ClassEntity> _constructorReferences = {};

  final Map<FunctionEntity, List<JParameterStub>> _parameterStubs = {};

  CodegenWorldBuilder(
    this._closedWorld,
    this._inferredData,
    this._selectorConstraintsStrategy,
    this._oneShotInterceptorData,
  );

  ElementEnvironment get _elementEnvironment => _closedWorld.elementEnvironment;

  NativeBasicData get _nativeBasicData => _closedWorld.nativeData;

  Iterable<ClassEntity> get instantiatedClasses => _processedClasses.keys.where(
    (cls) => _processedClasses[cls]!.isInstantiated,
  );

  // TODO(johnniwinther): Improve semantic precision.
  Iterable<ClassEntity> get directlyInstantiatedClasses {
    return _directlyInstantiatedClasses;
  }

  /// Register [type] as (directly) instantiated.
  // TODO(johnniwinther): Fully enforce the separation between exact, through
  // subclass and through subtype instantiated types/classes.
  // TODO(johnniwinther): Support unknown type arguments for generic types.
  void registerTypeInstantiation(
    InterfaceType type,
    ClassUsedCallback classUsed,
  ) {
    ClassEntity cls = type.element;
    bool isNative = _nativeBasicData.isNativeClass(cls);
    _instantiatedTypes.add(type);
    // We can't use the closed-world assumption with native abstract
    // classes; a native abstract class may have non-abstract subclasses
    // not declared to the program.  Instances of these classes are
    // indistinguishable from the abstract class.
    if (!cls.isAbstract || isNative) {
      _directlyInstantiatedClasses.add(cls);
      _processInstantiatedClass(cls, classUsed);
    }

    // TODO(johnniwinther): Replace this by separate more specific mappings that
    // include the type arguments.
    if (_implementedClasses.add(cls)) {
      classUsed(cls, _getClassUsage(cls).implement());
      _elementEnvironment.forEachSupertype(cls, (InterfaceType supertype) {
        if (_implementedClasses.add(supertype.element)) {
          classUsed(
            supertype.element,
            _getClassUsage(supertype.element).implement(),
          );
        }
      });
    }
  }

  bool _hasMatchingSelector(
    Map<Selector, SelectorConstraints>? selectors,
    MemberEntity member,
    JClosedWorld world,
  ) {
    if (selectors == null) return false;
    for (Selector selector in selectors.keys) {
      if (selector.appliesUnnamed(member)) {
        SelectorConstraints masks = selectors[selector]!;
        if (masks.canHit(member, selector.memberName, world)) {
          return true;
        }
      }
    }
    return false;
  }

  Iterable<CallStructure> _getMatchingCallStructures(
    Map<Selector, SelectorConstraints>? selectors,
    MemberEntity member,
  ) {
    if (selectors == null) return const [];
    Set<CallStructure>? callStructures;
    for (Selector selector in selectors.keys) {
      if (selector.appliesUnnamed(member)) {
        SelectorConstraints masks = selectors[selector]!;
        if (masks.canHit(member, selector.memberName, _closedWorld)) {
          callStructures ??= {};
          callStructures.add(selector.callStructure);
        }
      }
    }
    return callStructures ?? const [];
  }

  Iterable<CallStructure> _getInvocationCallStructures(MemberEntity member) {
    return _getMatchingCallStructures(_invokedNames[member.name], member);
  }

  bool _hasInvokedGetter(MemberEntity member) {
    return _hasMatchingSelector(
      _invokedGetters[member.name],
      member,
      _closedWorld,
    );
  }

  bool _hasInvokedSetter(MemberEntity member) {
    return _hasMatchingSelector(
      _invokedSetters[member.name],
      member,
      _closedWorld,
    );
  }

  void registerDynamicUse(
    DynamicUse dynamicUse,
    MemberUsedCallback memberUsed,
  ) {
    Selector selector = dynamicUse.selector;
    String methodName = selector.name;

    void process(
      Map<String, Set<MemberUsage>> memberMap,
      EnumSet<MemberUse> Function(MemberUsage usage) action,
      bool Function(MemberUsage usage) shouldBeRemoved,
    ) {
      _processSet(memberMap, methodName, (MemberUsage usage) {
        // Strategy will check both that selector applies and constraint is met.
        if (_selectorConstraintsStrategy.appliedUnnamed(
          dynamicUse,
          usage.entity,
          _closedWorld,
        )) {
          memberUsed(usage.entity, action(usage));
          return shouldBeRemoved(usage);
        }
        return false;
      });
    }

    switch (dynamicUse.kind) {
      case DynamicUseKind.invoke:
        registerDynamicInvocation(
          dynamicUse.selector,
          dynamicUse.typeArguments,
        );
        if (_registerNewSelector(dynamicUse, _invokedNames)) {
          process(
            _invokableInstanceMembersByName,
            (m) => m.invoke(Accesses.dynamicAccess, selector.callStructure),
            // If not all optional parameters have been passed in invocations
            // we must keep the member in [_invokableInstanceMembersByName].
            (u) => !u.hasPendingDynamicInvoke,
          );
        }
        break;
      case DynamicUseKind.get:
        if (_registerNewSelector(dynamicUse, _invokedGetters)) {
          process(
            _readableInstanceMembersByName,
            (m) => m.read(Accesses.dynamicAccess),
            (u) => !u.hasPendingDynamicRead,
          );
        }
        break;
      case DynamicUseKind.set:
        if (_registerNewSelector(dynamicUse, _invokedSetters)) {
          process(
            _writableInstanceMembersByName,
            (m) => m.write(Accesses.dynamicAccess),
            (u) => !u.hasPendingDynamicWrite,
          );
        }
        break;
    }
  }

  bool _registerNewSelector(
    DynamicUse dynamicUse,
    Map<String, Map<Selector, SelectorConstraints>> selectorMap,
  ) {
    Selector selector = dynamicUse.selector;
    String name = selector.name;
    Object? constraint = dynamicUse.receiverConstraint;
    Map<Selector, SelectorConstraints> selectors = selectorMap[name] ??=
        Maplet<Selector, SelectorConstraints>();
    UniverseSelectorConstraints? constraints =
        selectors[selector] as UniverseSelectorConstraints?;
    if (constraints == null) {
      selectors[selector] = _selectorConstraintsStrategy
          .createSelectorConstraints(selector, constraint);
      return true;
    }
    return constraints.addReceiverConstraint(constraint);
  }

  void registerIsCheck(covariant DartType type) {
    _isChecks.add(type);
  }

  void registerNamedTypeVariable(TypeVariableType type) {
    _namedTypeVariables.add(type);
  }

  void registerStaticUse(StaticUse staticUse, MemberUsedCallback memberUsed) {
    MemberEntity element = staticUse.element as MemberEntity;
    var (usage, useSet) = _getMemberUsage(element);
    switch (staticUse.kind) {
      case StaticUseKind.staticTearOff:
        useSet = useSet.union(usage.read(Accesses.staticAccess));
        break;
      case StaticUseKind.instanceFieldGet:
      case StaticUseKind.instanceFieldSet:
      case StaticUseKind.callMethod:
        // TODO(johnniwinther): Avoid this. Currently [FIELD_GET] and
        // [FIELD_SET] contains [BoxFieldElement]s which we cannot enqueue.
        // Also [CLOSURE] contains [LocalFunctionElement] which we cannot
        // enqueue.
        break;
      case StaticUseKind.superInvoke:
        registerStaticInvocation(staticUse);
        useSet = useSet.union(
          usage.invoke(Accesses.superAccess, staticUse.callStructure!),
        );
        break;
      case StaticUseKind.staticInvoke:
        registerStaticInvocation(staticUse);
        useSet = useSet.union(
          usage.invoke(Accesses.staticAccess, staticUse.callStructure!),
        );
        break;
      case StaticUseKind.superFieldSet:
        useSet = useSet.union(usage.write(Accesses.superAccess));
        break;
      case StaticUseKind.superSetterSet:
        useSet = useSet.union(usage.write(Accesses.superAccess));
        break;
      case StaticUseKind.staticSet:
        useSet = useSet.union(usage.write(Accesses.staticAccess));
        break;
      case StaticUseKind.superTearOff:
        useSet = useSet.union(usage.read(Accesses.superAccess));
        break;
      case StaticUseKind.superGet:
        useSet = useSet.union(usage.read(Accesses.superAccess));
        break;
      case StaticUseKind.staticGet:
        useSet = useSet.union(usage.read(Accesses.staticAccess));
        break;
      case StaticUseKind.fieldInit:
        useSet = useSet.union(usage.init());
        break;
      case StaticUseKind.fieldConstantInit:
        useSet = useSet.union(usage.constantInit(staticUse.constant!));
        break;
      case StaticUseKind.constructorInvoke:
      case StaticUseKind.constConstructorInvoke:
        // We don't track parameters in the codegen world builder, so we
        // pass `null` instead of the concrete call structure.
        useSet = useSet.union(
          usage.invoke(Accesses.staticAccess, staticUse.callStructure!),
        );
        break;
      case StaticUseKind.directInvoke:
        // We don't track parameters in the codegen world builder, so we
        // pass `null` instead of the concrete call structure.
        useSet = useSet.union(
          usage.invoke(Accesses.staticAccess, staticUse.callStructure!),
        );
        if (staticUse.typeArguments?.isNotEmpty ?? false) {
          registerDynamicInvocation(
            Selector.call(element.memberName, staticUse.callStructure!),
            staticUse.typeArguments!,
          );
        }
        break;
      case StaticUseKind.inlining:
        registerStaticInvocation(staticUse);
        break;
      case StaticUseKind.closure:
      case StaticUseKind.closureCall:
      case StaticUseKind.weakStaticTearOff:
        failedAt(
          currentElementSpannable,
          "Static use ${staticUse.kind} is not supported during codegen.",
        );
    }
    if (useSet.isNotEmpty) {
      memberUsed(usage.entity, useSet);
    }
  }

  void processClassMembers(
    ClassEntity cls,
    MemberUsedCallback memberUsed, {
    bool checkEnqueuerConsistency = false,
  }) {
    _elementEnvironment.forEachClassMember(cls, (
      ClassEntity cls,
      MemberEntity member,
    ) {
      _processInstantiatedClassMember(
        cls,
        member,
        memberUsed,
        checkEnqueuerConsistency: checkEnqueuerConsistency,
      );
    });
  }

  void _processInstantiatedClassMember(
    ClassEntity cls,
    MemberEntity member,
    MemberUsedCallback memberUsed, {
    bool checkEnqueuerConsistency = false,
  }) {
    if (!member.isInstanceMember) return;
    var (usage, useSet) = _getMemberUsage(member);
    if (useSet.isNotEmpty) {
      if (checkEnqueuerConsistency) {
        throw SpannableAssertionFailure(
          member,
          'Unenqueued usage of $member: \nbefore: <none>\nafter : $usage',
        );
      } else {
        memberUsed(member, useSet);
      }
    }
  }

  (MemberUsage, EnumSet<MemberUse>) _getMemberUsage(
    MemberEntity member, {
    bool checkEnqueuerConsistency = false,
  }) {
    EnumSet<MemberUse> useSet = EnumSet.empty();
    // TODO(johnniwinther): Change [TypeMask] to not apply to a superclass
    // member unless the class has been instantiated. Similar to
    // [StrongModeConstraint].
    MemberUsage? usage = _memberUsage[member];
    if (usage == null) {
      MemberAccess? potentialAccess = _closedWorld.getMemberAccess(member);
      if (member.isInstanceMember) {
        String memberName = member.name!;
        ClassEntity cls = member.enclosingClass!;
        bool isNative = _nativeBasicData.isNativeClass(cls);
        usage = MemberUsage(member, potentialAccess: potentialAccess);
        if (member is FieldEntity && !isNative) {
          useSet = useSet.union(usage.init());
        }
        if (member is JSignatureMethod) {
          // We mark signature methods as "always used" to prevent them from
          // being optimized away.
          // TODO(johnniwinther): Make this a part of the regular enqueueing.
          useSet = useSet.union(
            usage.invoke(Accesses.dynamicAccess, CallStructure.noArgs),
          );
        }

        if (usage.hasPendingDynamicRead && _hasInvokedGetter(member)) {
          useSet = useSet.union(usage.read(Accesses.dynamicAccess));
        }
        if (usage.hasPendingDynamicWrite && _hasInvokedSetter(member)) {
          useSet = useSet.union(usage.write(Accesses.dynamicAccess));
        }
        if (usage.hasPendingDynamicInvoke) {
          Iterable<CallStructure> callStructures = _getInvocationCallStructures(
            member,
          );
          for (CallStructure callStructure in callStructures) {
            useSet = useSet.union(
              usage.invoke(Accesses.dynamicAccess, callStructure),
            );
            if (!usage.hasPendingDynamicInvoke) {
              break;
            }
          }
        }

        if (!checkEnqueuerConsistency) {
          if (usage.hasPendingDynamicInvoke) {
            _invokableInstanceMembersByName
                .putIfAbsent(memberName, () => {})
                .add(usage);
          }
          if (usage.hasPendingDynamicRead) {
            _readableInstanceMembersByName
                .putIfAbsent(memberName, () => {})
                .add(usage);
          }
          if (usage.hasPendingDynamicWrite) {
            _writableInstanceMembersByName
                .putIfAbsent(memberName, () => {})
                .add(usage);
          }
        }
      } else {
        usage = MemberUsage(member, potentialAccess: potentialAccess);
        if (member is FieldEntity) {
          useSet = useSet.union(usage.init());
        }
      }
      if (!checkEnqueuerConsistency) {
        _memberUsage[member] = usage;
      }
    } else {
      if (checkEnqueuerConsistency) {
        usage = usage.clone();
      }
    }
    return (usage, useSet);
  }

  void _processSet(
    Map<String, Set<MemberUsage>> map,
    String memberName,
    bool Function(MemberUsage e) f,
  ) {
    Set<MemberUsage>? members = map[memberName];
    if (members == null) return;
    // [f] might add elements to [: map[memberName] :] during the loop below
    // so we create a new list for [: map[memberName] :] and prepend the
    // [remaining] members after the loop.
    map[memberName] = {};
    Set<MemberUsage> remaining = {};
    for (MemberUsage member in members) {
      if (!f(member)) remaining.add(member);
    }
    map[memberName]!.addAll(remaining);
  }

  /// Return the canonical [ClassUsage] for [cls].
  ClassUsage _getClassUsage(ClassEntity cls) {
    return _processedClasses.putIfAbsent(cls, () => ClassUsage(cls));
  }

  void _processInstantiatedClass(ClassEntity cls, ClassUsedCallback classUsed) {
    // Registers [superclass] as instantiated. Returns `true` if it wasn't
    // already instantiated and we therefore have to process its superclass as
    // well.
    bool processClass(ClassEntity superclass) {
      ClassUsage usage = _getClassUsage(superclass);
      if (!usage.isInstantiated) {
        classUsed(usage.cls, usage.instantiate());
        return true;
      }
      return false;
    }

    ClassEntity? current = cls;
    while (current != null && processClass(current)) {
      current = _elementEnvironment.getSuperClass(current);
    }
  }

  /// Set of all registered compiled constants.
  final Set<ConstantValue> _compiledConstants = {};

  Iterable<ConstantValue> get compiledConstantsForTesting => _compiledConstants;

  void addCompileTimeConstantForEmission(ConstantValue constant) {
    _compiledConstants.add(constant);
  }

  /// Register the constant [use] with this world builder. Returns `true` if
  /// the constant use was new to the world.
  bool registerConstantUse(ConstantUse use) {
    addCompileTimeConstantForEmission(use.value);
    return _constantValues.add(use.value);
  }

  void registerConstTypeLiteral(DartType type) {
    _constTypeLiterals.add(type);
  }

  void registerTypeArgument(DartType type) {
    _liveTypeArguments.add(type);
  }

  void registerConstructorReference(InterfaceType type) {
    _constructorReferences.add(type.element);
  }

  bool _canTearOffFunction(FunctionEntity member, MemberUsage usage) {
    if (!member.isFunction) return false;
    if (member.isInstanceMember) {
      if (member.enclosingClass!.isClosure) return false;
      if (usage.reads.contains(Access.superAccess)) return true;
      if (_hasInvokedGetter(member)) return true;
      return false;
    } else {
      if (member is ConstructorEntity) return false;
      assert(member.isStatic || member.isTopLevel);
      return usage.hasRead;
    }
  }

  bool _methodCanBeApplied(FunctionEntity method) {
    return _closedWorld.backendUsage.isFunctionApplyUsed &&
        _inferredData.getMightBePassedToApply(method);
  }

  bool _functionNeedsStubs(FunctionEntity member) {
    if (member.isAbstract) return false;
    if (member is JGeneratorBody) return false;
    if (member is ConstructorBodyEntity) return false;
    return member.parameterStructure.optionalParameters != 0 ||
        member.parameterStructure.typeParameters != 0;
  }

  List<JParameterStub> generateParameterStubs() {
    List<JParameterStub> newStubs = [];
    _memberUsage.forEach((member, usage) {
      if (member is! FunctionEntity) return;
      if (member is JParameterStub) return;
      if (!usage.hasUse) return;
      if (!_functionNeedsStubs(member)) return;

      final Map<Selector, SelectorConstraints> liveSelectors =
          // Only instance members (not static methods) need stubs.
          (member.isInstanceMember ? _invokedNames[member.name!] : const {}) ??
          const {};
      final Map<Selector, SelectorConstraints> callSelectors =
          (_canTearOffFunction(member, usage)
              ? _invokedNames[Identifiers.call]
              : const {}) ??
          const {};

      bool canBeApplied = _methodCanBeApplied(member);
      int memberTypeParameters = member.parameterStructure.typeParameters;

      if (liveSelectors.isEmpty &&
          callSelectors.isEmpty &&
          // Function.apply might need a stub to default the type parameter.
          !(canBeApplied && memberTypeParameters > 0)) {
        return;
      }

      // For every call-selector the corresponding selector with the name of the
      // member.
      //
      // For example, for the call-selector `call(x, y)` the renamed selector
      // for member `foo` would be `foo(x, y)`.
      Set<Selector> renamedCallSelectors = {};

      Set<Selector> stubSelectors = {};

      void createStub(
        FunctionEntity member,
        Selector selector, {
        Selector? callSelector,
        required bool needsSuper,
      }) {
        if (_parameterStubs[member]?.any(
              (e) =>
                  e.parameterStructure.callStructure == selector.callStructure,
            ) ??
            false) {
          return;
        }
        final stub = _generateParameterStub(
          member,
          selector,
          callSelector: callSelector,
          needsSuper: needsSuper,
        );
        if (stub == null) return;

        newStubs.add(stub);
        (_parameterStubs[member] ??= []).add(stub);
        if (needsSuper) {
          // We need to force the accesses here since the target member may not
          // have a pending super invoke. This ensures that the emitter uses the
          // aliased name for this super invocation.
          usage.invoke(
            Accesses.superAccess,
            member.parameterStructure.callStructure,
            forceAccesses: true,
          );
        }
      }

      bool needsSuper = usage.reads.contains(Access.superAccess);

      // Start with closure-call selectors, since they imply the generation
      // of the non-call version.
      if (canBeApplied && memberTypeParameters > 0) {
        // Function.apply calls the function with no type arguments, so generic
        // methods need the stub to default the type arguments.
        // This has to be the first stub.
        Selector namedSelector = Selector.fromElement(member).toNonGeneric();
        Selector closureSelector = namedSelector.toCallSelector();

        renamedCallSelectors.add(namedSelector);
        stubSelectors.add(namedSelector);
        createStub(
          member,
          namedSelector,
          callSelector: closureSelector,
          needsSuper: needsSuper,
        );
      }

      for (Selector selector in callSelectors.keys) {
        Selector renamedSelector = Selector.call(
          member.memberName,
          selector.callStructure,
        );
        renamedCallSelectors.add(renamedSelector);

        if (!renamedSelector.appliesUnnamed(member)) {
          continue;
        }

        if (stubSelectors.add(renamedSelector)) {
          createStub(
            member,
            renamedSelector,
            callSelector: selector,
            needsSuper: needsSuper,
          );
        }

        // A generic method might need to support `call<T>(x)` for a generic
        // instantiation stub without `call<T>(x)` being in [callSelectors].
        // [selector] will be `call(x)` (that already passes the appliesUnnamed
        // check by defaulting type arguments), and the method will be generic.
        //
        // This is basically the same logic as above, but with type arguments.
        if (selector.callStructure.typeArgumentCount == 0) {
          if (memberTypeParameters > 0) {
            Selector renamedSelectorWithTypeArguments = Selector.call(
              member.memberName,
              selector.callStructure.withTypeArgumentCount(
                memberTypeParameters,
              ),
            );
            renamedCallSelectors.add(renamedSelectorWithTypeArguments);

            if (stubSelectors.add(renamedSelectorWithTypeArguments)) {
              Selector closureSelector = Selector.callClosureFrom(
                renamedSelectorWithTypeArguments,
              );
              createStub(
                member,
                renamedSelectorWithTypeArguments,
                callSelector: closureSelector,
                needsSuper: needsSuper,
              );
            }
          }
        }
      }

      // Now run through the actual member selectors (eg. `foo$2(x, y)` and not
      // `call$2(x, y)`). Some of them have already been generated because of the
      // call-selectors and they are in the renamedCallSelectors set.
      for (Selector selector in liveSelectors.keys) {
        if (renamedCallSelectors.contains(selector)) continue;
        if (!selector.appliesUnnamed(member)) continue;
        if (!liveSelectors[selector]!.canHit(
          member,
          selector.memberName,
          _closedWorld,
        )) {
          continue;
        }

        if (stubSelectors.add(selector)) {
          createStub(member, selector, needsSuper: needsSuper);
        }
      }
    });
    return newStubs;
  }

  JParameterStub? _generateParameterStub(
    FunctionEntity member,
    Selector selector, {
    Selector? callSelector,
    required bool needsSuper,
  }) {
    ParameterStructure parameterStructure = member.parameterStructure;
    final callStructure = selector.callStructure;
    int positionalArgumentCount = callStructure.positionalArgumentCount;
    if (callStructure.typeArgumentCount == parameterStructure.typeParameters) {
      if (positionalArgumentCount == parameterStructure.totalParameters) {
        // Positional optional arguments are all provided.
        assert(callStructure.isUnnamed);
        return null;
      }
      if (parameterStructure.namedParameters.isNotEmpty &&
          callStructure.namedArgumentCount ==
              parameterStructure.namedParameters.length) {
        // Named optional arguments are all provided.
        return null;
      }
    }
    return _closedWorld.elementMap.createParameterStub(
      member as JFunction,
      selector,
      callSelector: callSelector,
      needsSuper: needsSuper,
    );
  }

  CodegenWorld close() {
    Map<MemberEntity, MemberUsage> liveMemberUsage = {};
    _memberUsage.forEach((MemberEntity member, MemberUsage usage) {
      if (usage.hasUse) {
        liveMemberUsage[member] = usage;
      }
    });
    return CodegenWorldImpl(
      _closedWorld,
      liveMemberUsage,
      processedEntities,
      constTypeLiterals: _constTypeLiterals,
      constructorReferences: _constructorReferences,
      directlyInstantiatedClasses: directlyInstantiatedClasses,
      typeVariableTypeLiterals: typeVariableTypeLiterals,
      instantiatedClasses: instantiatedClasses,
      isChecks: _isChecks,
      namedTypeVariables: _namedTypeVariables,
      instantiatedTypes: _instantiatedTypes,
      liveTypeArguments: _liveTypeArguments,
      compiledConstants: _compiledConstants,
      invokedNames: _invokedNames,
      invokedGetters: _invokedGetters,
      invokedSetters: _invokedSetters,
      staticTypeArgumentDependencies: staticTypeArgumentDependencies,
      dynamicTypeArgumentDependencies: dynamicTypeArgumentDependencies,
      oneShotInterceptorData: _oneShotInterceptorData,
      parameterStubs: _parameterStubs,
    );
  }
}

class CodegenWorldImpl implements CodegenWorld {
  final JClosedWorld _closedWorld;

  final Map<MemberEntity, MemberUsage> _liveMemberUsage;
  final Set<MemberEntity> _reachableLazyMemberBodies;

  @override
  final Iterable<DartType> constTypeLiterals;

  @override
  final Iterable<ClassEntity> constructorReferences;

  @override
  final Iterable<ClassEntity> directlyInstantiatedClasses;

  @override
  final Iterable<TypeVariableType> typeVariableTypeLiterals;

  @override
  final Iterable<ClassEntity> instantiatedClasses;

  @override
  final Iterable<DartType> isChecks;

  @override
  final Set<TypeVariableType> namedTypeVariables;

  @override
  final Iterable<InterfaceType> instantiatedTypes;

  @override
  final Iterable<DartType> liveTypeArguments;

  final Iterable<ConstantValue> _compiledConstants;

  final Map<String, Map<Selector, SelectorConstraints>> _invokedNames;

  final Map<String, Map<Selector, SelectorConstraints>> _invokedGetters;

  final Map<String, Map<Selector, SelectorConstraints>> _invokedSetters;

  final Map<Entity, Set<DartType>> _staticTypeArgumentDependencies;

  final Map<Selector, Set<DartType>> _dynamicTypeArgumentDependencies;

  final Map<FunctionEntity, List<JParameterStub>> _parameterStubs;

  @override
  final OneShotInterceptorData oneShotInterceptorData;

  CodegenWorldImpl(
    this._closedWorld,
    this._liveMemberUsage,
    Iterable<MemberEntity> processedEntities, {
    required this.constTypeLiterals,
    required this.constructorReferences,
    required this.directlyInstantiatedClasses,
    required this.typeVariableTypeLiterals,
    required this.instantiatedClasses,
    required this.isChecks,
    required this.namedTypeVariables,
    required this.instantiatedTypes,
    required this.liveTypeArguments,
    required Map<FunctionEntity, List<JParameterStub>> parameterStubs,
    required Iterable<ConstantValue> compiledConstants,
    required Map<String, Map<Selector, SelectorConstraints>> invokedNames,
    required Map<String, Map<Selector, SelectorConstraints>> invokedGetters,
    required Map<String, Map<Selector, SelectorConstraints>> invokedSetters,
    required Map<Entity, Set<DartType>> staticTypeArgumentDependencies,
    required Map<Selector, Set<DartType>> dynamicTypeArgumentDependencies,
    required this.oneShotInterceptorData,
  }) : _parameterStubs = parameterStubs,
       _reachableLazyMemberBodies = processedEntities
           .where((e) => e is JGeneratorBody || e is JConstructorBody)
           .toSet(),
       _compiledConstants = compiledConstants,
       _invokedNames = invokedNames,
       _invokedGetters = invokedGetters,
       _invokedSetters = invokedSetters,
       _staticTypeArgumentDependencies = staticTypeArgumentDependencies,
       _dynamicTypeArgumentDependencies = dynamicTypeArgumentDependencies;

  @override
  AnnotationsData get annotationsData => _closedWorld.annotationsData;

  @override
  ClassHierarchy get classHierarchy => _closedWorld.classHierarchy;

  @override
  void forEachStaticField(void Function(FieldEntity) f) {
    _liveMemberUsage.forEach((MemberEntity member, MemberUsage usage) {
      if (member is FieldEntity && (member.isStatic || member.isTopLevel)) {
        f(member);
      }
    });
  }

  @override
  void forEachGenericMethod(void Function(FunctionEntity e) f) {
    _liveMemberUsage.forEach((MemberEntity member, MemberUsage usage) {
      if (member is FunctionEntity &&
          _closedWorld.elementEnvironment
              .getFunctionTypeVariables(member)
              .isNotEmpty) {
        f(member);
      }
    });
  }

  @override
  void forEachGenericInstanceMethod(void Function(FunctionEntity e) f) {
    _liveMemberUsage.forEach((MemberEntity member, MemberUsage usage) {
      if (member is FunctionEntity &&
          member.isInstanceMember &&
          _closedWorld.elementEnvironment
              .getFunctionTypeVariables(member)
              .isNotEmpty) {
        f(member);
      }
    });
  }

  @override
  void forEachGenericClosureCallMethod(void Function(FunctionEntity e) f) {
    _liveMemberUsage.forEach((MemberEntity member, MemberUsage usage) {
      if (member.name == Identifiers.call &&
          member.isInstanceMember &&
          member.enclosingClass!.isClosure &&
          member is FunctionEntity &&
          _closedWorld.elementEnvironment
              .getFunctionTypeVariables(member)
              .isNotEmpty) {
        f(member);
      }
    });
  }

  @override
  late final Iterable<FunctionEntity> userNoSuchMethods = [
    for (MemberEntity member in _liveMemberUsage.keys)
      if (member is FunctionEntity &&
          member.isInstanceMember &&
          member.name == Identifiers.noSuchMethod_ &&
          !_closedWorld.commonElements.isDefaultNoSuchMethodImplementation(
            member,
          ))
        member,
  ];

  @override
  Iterable<Local> get genericLocalFunctions => const [];

  @override
  late final Iterable<FunctionEntity> closurizedMembers = (() {
    final result = <FunctionEntity>{};
    _liveMemberUsage.forEach((MemberEntity member, MemberUsage usage) {
      if ((member.isFunction || member is JGeneratorBody) &&
          member.isInstanceMember &&
          usage.hasRead) {
        result.add(member as FunctionEntity);
      }
    });
    return result;
  })();

  @override
  late final Iterable<FunctionEntity> closurizedStatics = (() {
    final result = <FunctionEntity>{};
    _liveMemberUsage.forEach((MemberEntity member, MemberUsage usage) {
      if (member.isFunction &&
          (member.isStatic || member.isTopLevel) &&
          usage.hasRead) {
        result.add(member as FunctionEntity);
      }
    });
    return result;
  })();

  @override
  late final Map<MemberEntity, DartType> genericCallableProperties = (() {
    final result = <MemberEntity, DartType>{};
    _liveMemberUsage.forEach((MemberEntity member, MemberUsage usage) {
      if (usage.hasRead) {
        DartType? type;
        if (member is FieldEntity) {
          type = _closedWorld.elementEnvironment.getFieldType(member);
        } else if (member.isGetter) {
          type = _closedWorld.elementEnvironment
              .getFunctionType(member as FunctionEntity)
              .returnType;
        }
        if (type == null) return;
        if (_closedWorld.dartTypes.canAssignGenericFunctionTo(type)) {
          result[member] = type;
        } else {
          type = type.withoutNullability;
          if (type is InterfaceType) {
            FunctionType? callType = _closedWorld.dartTypes.getCallType(type);
            if (callType != null &&
                _closedWorld.dartTypes.canAssignGenericFunctionTo(callType)) {
              result[member] = callType;
            }
          }
        }
      }
    });
    return result;
  })();

  @override
  void forEachStaticTypeArgument(
    void Function(Entity function, Set<DartType> typeArguments) f,
  ) {
    _staticTypeArgumentDependencies.forEach(f);
  }

  @override
  void forEachDynamicTypeArgument(
    void Function(Selector selector, Set<DartType> typeArguments) f,
  ) {
    _dynamicTypeArgumentDependencies.forEach(f);
  }

  @override
  void forEachInvokedName(
    void Function(String name, Map<Selector, SelectorConstraints> selectors) f,
  ) {
    _invokedNames.forEach(f);
  }

  @override
  void forEachInvokedGetter(
    void Function(String name, Map<Selector, SelectorConstraints> selectors) f,
  ) {
    _invokedGetters.forEach(f);
  }

  @override
  void forEachInvokedSetter(
    void Function(String name, Map<Selector, SelectorConstraints> selectors) f,
  ) {
    _invokedSetters.forEach(f);
  }

  @override
  bool hasInvokedGetter(MemberEntity member) {
    MemberUsage? memberUsage = _liveMemberUsage[member];
    if (memberUsage == null) return false;
    return memberUsage.reads.contains(Access.dynamicAccess);
  }

  @override
  bool methodsNeedsSuperGetter(FunctionEntity function) {
    MemberUsage? memberUsage = _liveMemberUsage[function];
    if (memberUsage == null) return false;
    return memberUsage.reads.contains(Access.superAccess);
  }

  @override
  bool hasInvokedSetter(MemberEntity member) {
    MemberUsage? memberUsage = _liveMemberUsage[member];
    if (memberUsage == null) return false;
    return memberUsage.writes.contains(Access.dynamicAccess);
  }

  Map<Selector, SelectorConstraints>? _asUnmodifiable(
    Map<Selector, SelectorConstraints>? map,
  ) {
    if (map == null) return null;
    return UnmodifiableMapView(map);
  }

  @override
  Map<Selector, SelectorConstraints>? invocationsByName(String name) {
    return _asUnmodifiable(_invokedNames[name]);
  }

  @override
  Iterable<Selector>? getterInvocationsByName(String name) {
    return _invokedGetters[name]?.keys;
  }

  @override
  Iterable<Selector>? setterInvocationsByName(String name) {
    return _invokedSetters[name]?.keys;
  }

  @override
  Iterable<ConstantValue> getConstantsForEmission([
    Comparator<ConstantValue>? preSortCompare,
  ]) {
    // We must emit dependencies before their uses.
    Set<ConstantValue> seenConstants = {};
    List<ConstantValue> result = [];

    void addConstant(ConstantValue constant) {
      if (!seenConstants.contains(constant)) {
        constant.getDependencies().forEach(addConstant);
        assert(!seenConstants.contains(constant));
        result.add(constant);
        seenConstants.add(constant);
      }
    }

    if (preSortCompare != null) {
      List<ConstantValue> sorted = _compiledConstants.toList();
      sorted.sort(preSortCompare);
      sorted.forEach(addConstant);
    } else {
      _compiledConstants.forEach(addConstant);
    }
    return result;
  }

  @override
  bool isAliasedSuperMember(MemberEntity member) {
    MemberUsage? usage = _liveMemberUsage[member];
    if (usage == null) return false;
    return usage.invokes.contains(Access.superAccess) ||
        usage.writes.contains(Access.superAccess);
  }

  @override
  bool isLateMemberReachable(MemberEntity member) {
    return _reachableLazyMemberBodies.contains(member);
  }

  @override
  Iterable<JParameterStub> getParameterStubs(FunctionEntity member) {
    return _parameterStubs[member] ?? const [];
  }
}