pkg/compiler/lib/src/js_model/js_strategy.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.

library;

import 'package:kernel/ast.dart' as ir;

import '../common.dart';
import '../common/codegen.dart';
import '../common/elements.dart' show CommonElements, ElementEnvironment;
import '../common/tasks.dart';
import '../common/work.dart';
import '../compiler.dart';
import '../deferred_load/output_unit.dart'
    show LateOutputUnitDataBuilder, OutputUnitData;
import '../dump_info.dart';
import '../elements/entities.dart';
import '../enqueue.dart';
import '../inferrer/abstract_value_domain.dart';
import '../io/kernel_source_information.dart'
    show OnlineKernelSourceInformationStrategy;
import '../io/source_information.dart';
import '../inferrer/type_graph_inferrer.dart';
import '../inferrer/types.dart';
import '../js/js_source_mapping.dart';
import '../js_backend/backend.dart';
import '../js_backend/backend_impact.dart';
import '../js_backend/codegen_inputs.dart';
import '../js_backend/codegen_listener.dart';
import '../js_backend/custom_elements_analysis.dart';
import '../js_backend/enqueuer.dart';
import '../js_backend/impact_transformer.dart';
import '../js_backend/inferred_data.dart';
import '../js_backend/interceptor_data.dart';
import '../js_backend/namer.dart'
    show
        FixedNames,
        FrequencyBasedNamer,
        MinifiedFixedNames,
        MinifyNamer,
        ModularNamer,
        Namer;
import '../js_backend/records_codegen.dart';
import '../js_backend/runtime_types.dart';
import '../js_backend/runtime_types_codegen.dart';
import '../js_backend/runtime_types_new.dart' show RecipeEncoder;
import '../js_backend/runtime_types_new.dart' show RecipeEncoderImpl;
import '../js_emitter/code_emitter_task.dart' show ModularEmitter;
import '../js_emitter/js_emitter.dart' show CodeEmitterTask;
import '../js_model/js_world.dart' show JClosedWorld;
import '../js/js.dart' as js;
import '../kernel/kernel_strategy.dart';
import '../kernel/kernel_world.dart';
import '../native/behavior.dart';
import '../native/enqueue.dart';
import '../options.dart';
import '../serialization/serialization.dart';
import '../ssa/builder.dart';
import '../ssa/metrics.dart';
import '../ssa/nodes.dart';
import '../ssa/ssa.dart';
import '../ssa/types.dart';
import '../tracer.dart';
import '../universe/codegen_world_builder.dart';
import '../universe/selector.dart';
import '../universe/world_impact.dart';
import 'closure.dart';
import 'element_map.dart';
import 'element_map_impl.dart';
import 'js_world.dart';
import 'js_world_builder.dart' show JClosedWorldBuilder;
import 'locals.dart';
import 'records.dart' show RecordDataBuilder;

/// JS Strategy pattern that defines the element model used in type inference
/// and code generation.
class JsBackendStrategy {
  final Compiler _compiler;
  late JsKernelToElementMap _elementMap;

  bool _isInitialized = false;

  /// Codegen support for generating table of interceptors and
  /// constructors for custom elements.
  late final CustomElementsCodegenAnalysis _customElementsCodegenAnalysis;

  late final RecordsCodegen _recordsCodegen;

  late final NativeCodegenEnqueuer _nativeCodegenEnqueuer;

  late final Namer _namer;

  late final CodegenImpactTransformer _codegenImpactTransformer;

  late final CodeEmitterTask _emitterTask;

  late final RuntimeTypesChecksBuilder _rtiChecksBuilder;

  late final FunctionCompiler _functionCompiler;

  late SourceInformationStrategy sourceInformationStrategy;

  final SsaMetrics _ssaMetrics = SsaMetrics();

  /// The generated code as a js AST for compiled methods.
  final Map<MemberEntity, js.Expression> generatedCode = {};

  JsBackendStrategy(this._compiler) {
    bool generateSourceMap = _compiler.options.generateSourceMap;
    if (!generateSourceMap) {
      sourceInformationStrategy = const JavaScriptSourceInformationStrategy();
    } else {
      sourceInformationStrategy = OnlineKernelSourceInformationStrategy();
    }
    _emitterTask = CodeEmitterTask(_compiler, generateSourceMap);
    _functionCompiler = SsaFunctionCompiler(
      _compiler.options,
      _compiler.reporter,
      _ssaMetrics,
      this,
      _compiler.measurer,
      sourceInformationStrategy,
    );
  }

  List<CompilerTask> get tasks {
    List<CompilerTask> result = functionCompiler.tasks;
    result.add(emitterTask);
    return result;
  }

  FunctionCompiler get functionCompiler => _functionCompiler;

  CodeEmitterTask get emitterTask => _emitterTask;

  Namer get namerForTesting => _namer;

  NativeCodegenEnqueuer get nativeCodegenEnqueuer => _nativeCodegenEnqueuer;

  RuntimeTypesChecksBuilder get rtiChecksBuilderForTesting => _rtiChecksBuilder;

  Map<MemberEntity, WorldImpact>? codegenImpactsForTesting;

  String? getGeneratedCodeForTesting(MemberEntity element) {
    if (generatedCode[element] == null) return null;
    return js.prettyPrint(
      generatedCode[element]!,
      enableMinification: _compiler.options.enableMinification,
    );
  }

  /// Codegen support for generating table of interceptors and
  /// constructors for custom elements.
  CustomElementsCodegenAnalysis get customElementsCodegenAnalysis =>
      _customElementsCodegenAnalysis;

  RecordsCodegen get recordsCodegen => _recordsCodegen;

  RuntimeTypesChecksBuilder get rtiChecksBuilder {
    assert(
      !_rtiChecksBuilder.rtiChecksBuilderClosed,
      failedAt(
        noLocationSpannable,
        "RuntimeTypesChecks has already been computed.",
      ),
    );
    return _rtiChecksBuilder;
  }

  /// Create the [JClosedWorld] from [closedWorld].
  JClosedWorld createJClosedWorld(
    KClosedWorld closedWorld,
    OutputUnitData outputUnitData,
  ) {
    KernelFrontendStrategy strategy = _compiler.frontendStrategy;
    _elementMap = JsKernelToElementMap(
      _compiler.reporter,
      strategy.elementMap,
      closedWorld.liveMemberUsage,
      closedWorld.liveAbstractInstanceMembers,
      closedWorld.annotationsData,
    );
    ClosureDataBuilder closureDataBuilder = ClosureDataBuilder(
      _compiler.reporter,
      _elementMap,
      closedWorld.annotationsData,
    );
    RecordDataBuilder recordDataBuilder = RecordDataBuilder(
      _compiler.reporter,
      _elementMap,
      closedWorld.annotationsData,
    );
    JClosedWorldBuilder closedWorldBuilder = JClosedWorldBuilder(
      _elementMap,
      closureDataBuilder,
      recordDataBuilder,
      _compiler.options,
      _compiler.reporter,
      _compiler.abstractValueStrategy,
    );
    JClosedWorld jClosedWorld = closedWorldBuilder.convertClosedWorld(
      closedWorld,
      strategy.closureModels,
      outputUnitData,
    );
    _elementMap.lateOutputUnitDataBuilder = LateOutputUnitDataBuilder(
      jClosedWorld.outputUnitData,
    );
    return jClosedWorld;
  }

  /// Registers [closedWorld] as the current closed world used by this backend
  /// strategy.
  ///
  /// This is used to support serialization after type inference.
  void registerJClosedWorld(covariant JClosedWorld closedWorld) {
    _elementMap = closedWorld.elementMap;
    sourceInformationStrategy.onElementMapAvailable(_elementMap);
  }

  /// Called when the compiler starts running the codegen.
  ///
  /// Returns the [CodegenInputs] objects with the needed data.
  CodegenInputs onCodegenStart(
    GlobalTypeInferenceResults globalTypeInferenceResults,
  ) {
    JClosedWorld closedWorld = globalTypeInferenceResults.closedWorld;
    FixedNames fixedNames = _compiler.options.enableMinification
        ? const MinifiedFixedNames()
        : const FixedNames();

    Tracer tracer = Tracer(
      closedWorld,
      _compiler.options,
      _compiler.outputProvider,
    );

    RuntimeTypesSubstitutions rtiSubstitutions;
    if (_compiler.options.disableRtiOptimization) {
      final trivialSubs = rtiSubstitutions = TrivialRuntimeTypesSubstitutions(
        closedWorld,
      );
      _rtiChecksBuilder = TrivialRuntimeTypesChecksBuilder(
        closedWorld,
        trivialSubs,
      );
    } else {
      RuntimeTypesImpl runtimeTypesImpl = RuntimeTypesImpl(closedWorld);
      _rtiChecksBuilder = runtimeTypesImpl;
      rtiSubstitutions = runtimeTypesImpl;
    }

    RecipeEncoder rtiRecipeEncoder = RecipeEncoderImpl(
      closedWorld,
      rtiSubstitutions,
      closedWorld.nativeData,
      closedWorld.commonElements,
    );

    CodegenInputs codegen = CodegenInputs(
      rtiSubstitutions,
      rtiRecipeEncoder,
      tracer,
      fixedNames,
    );

    functionCompiler.initialize(globalTypeInferenceResults, codegen);
    return codegen;
  }

  /// Creates an [Enqueuer] for code generation specific to this backend.
  CodegenEnqueuer createCodegenEnqueuer(
    CompilerTask task,
    JClosedWorld closedWorld,
    InferredData inferredData,
    CodegenInputs codegen,
    CodegenResults codegenResults,
    SourceLookup sourceLookup,
  ) {
    initialize(closedWorld, codegen);
    ElementEnvironment elementEnvironment = closedWorld.elementEnvironment;
    CommonElements commonElements = closedWorld.commonElements;
    BackendImpacts impacts = BackendImpacts(commonElements, _compiler.options);
    _customElementsCodegenAnalysis = CustomElementsCodegenAnalysis(
      commonElements,
      elementEnvironment,
      closedWorld.nativeData,
    );
    _recordsCodegen = RecordsCodegen(commonElements, closedWorld.recordData);
    final worldBuilder = CodegenWorldBuilder(
      closedWorld,
      inferredData,
      _compiler.abstractValueStrategy.createSelectorStrategy(
        closedWorld.abstractValueDomain,
      ),
      _codegenImpactTransformer.oneShotInterceptorData,
    );
    return CodegenEnqueuer(
      task,
      worldBuilder,
      KernelCodegenWorkItemBuilder(
        this,
        closedWorld.abstractValueDomain,
        codegenResults,
        // TODO(johnniwinther): Avoid the need for a [ComponentLookup]. This
        // is caused by some type masks holding a kernel node for using in
        // tracing.
        ComponentLookup(_elementMap.programEnv.mainComponent),
        sourceLookup,
      ),
      CodegenEnqueuerListener(
        _compiler.options,
        elementEnvironment,
        commonElements,
        impacts,
        closedWorld.backendUsage,
        closedWorld.rtiNeed,
        closedWorld.recordData,
        customElementsCodegenAnalysis,
        recordsCodegen,
        closedWorld.nativeData,
        nativeCodegenEnqueuer,
        worldBuilder,
      ),
      closedWorld.annotationsData,
    );
  }

  /// Called before the compiler starts running the codegen enqueuer.
  void initialize(JClosedWorld closedWorld, CodegenInputs codegen) {
    // This can be initialized during the emitter phase and when running dump
    // info. Make sure if both are running together that this is only
    // initialized once.
    if (_isInitialized) return;
    _isInitialized = true;

    OneShotInterceptorData oneShotInterceptorData = OneShotInterceptorData(
      closedWorld.interceptorData,
      closedWorld.commonElements,
      closedWorld.nativeData,
    );
    FixedNames fixedNames = codegen.fixedNames;
    _namer = _compiler.options.enableMinification
        ? _compiler.options.useFrequencyNamer
              ? FrequencyBasedNamer(closedWorld, fixedNames)
              : MinifyNamer(closedWorld, fixedNames)
        : Namer(closedWorld, fixedNames);
    _nativeCodegenEnqueuer = NativeCodegenEnqueuer(
      _compiler.options,
      closedWorld.elementEnvironment,
      closedWorld.commonElements,
      closedWorld.dartTypes,
      emitterTask,
      closedWorld.liveNativeClasses,
      closedWorld.nativeData,
    );
    emitterTask.createEmitter(_namer, codegen, closedWorld);
    // TODO(johnniwinther): Share the impact object created in
    // createCodegenEnqueuer.
    BackendImpacts impacts = BackendImpacts(
      closedWorld.commonElements,
      _compiler.options,
    );

    _codegenImpactTransformer = CodegenImpactTransformer(
      closedWorld,
      closedWorld.elementEnvironment,
      impacts,
      closedWorld.nativeData,
      closedWorld.backendUsage,
      closedWorld.rtiNeed,
      nativeCodegenEnqueuer,
      _namer,
      oneShotInterceptorData,
      rtiChecksBuilder,
      emitterTask.nativeEmitter,
    );
  }

  WorldImpact transformCodegenImpact(CodegenImpact impact) {
    return _codegenImpactTransformer.transformCodegenImpact(impact);
  }

  WorldImpact generateCode(
    WorkItem work,
    AbstractValueDomain abstractValueDomain,
    CodegenResults codegenResults,
    ComponentLookup componentLookup,
    SourceLookup sourceLookup,
  ) {
    MemberEntity member = work.element;
    var (:result, :isGenerated) = codegenResults.getCodegenResults(member);
    if (_compiler.options.testMode) {
      final indices = SerializationIndices(testMode: true);
      bool useDataKinds = true;
      List<Object> data = [];
      DataSinkWriter sink = DataSinkWriter(
        ObjectDataSink(data),
        _compiler.options,
        indices,
        useDataKinds: useDataKinds,
      );
      sink.registerAbstractValueDomain(abstractValueDomain);
      result.writeToDataSink(sink);
      sink.close();
      DataSourceReader source = DataSourceReader(
        ObjectDataSource(data),
        _compiler.options,
        indices,
        useDataKinds: useDataKinds,
      );
      source.registerAbstractValueDomain(abstractValueDomain);
      source.registerComponentLookup(componentLookup);
      source.registerSourceLookup(sourceLookup);
      result = CodegenResult.readFromDataSource(source);
    }
    if (result.code != null) {
      generatedCode[member] = result.code!;
    }
    if (retainDataForTesting) {
      codegenImpactsForTesting ??= {};
      codegenImpactsForTesting![member] = result.impact;
    }

    // Register the untransformed impact here as dump info will transform it
    // again later if needed.
    _compiler.dumpInfoRegistry.registerImpact(
      member,
      result.impact,
      isGenerated: isGenerated,
    );
    WorldImpact worldImpact = _codegenImpactTransformer.transformCodegenImpact(
      result.impact,
    );
    result.applyModularState(_namer, emitterTask.emitter);
    return worldImpact;
  }

  /// Called when code generation has been completed.
  void onCodegenEnd(CodegenInputs codegen) {
    sourceInformationStrategy.onComplete();
    codegen.tracer.close();
  }

  /// Generates the output and returns the total size of the generated code.
  int assembleProgram(
    JClosedWorld closedWorld,
    InferredData inferredData,
    CodegenInputs codegenInputs,
    CodegenWorld codegenWorld,
  ) {
    int programSize = emitterTask.assembleProgram(
      _namer,
      closedWorld,
      inferredData,
      codegenInputs,
      codegenWorld,
    );
    closedWorld.noSuchMethodData.emitDiagnostic(_compiler.reporter);
    return programSize;
  }

  /// Creates the [SsaBuilder] used for the element model.
  SsaBuilder createSsaBuilder(
    CompilerTask task,
    JClosedWorld closedWorld,
    SourceInformationStrategy sourceInformationStrategy,
  ) {
    return KernelSsaBuilder(
      task,
      _compiler.options,
      _compiler.reporter,
      _compiler.dumpInfoTask,
      _ssaMetrics,
      closedWorld,
      _elementMap,
      sourceInformationStrategy,
    );
  }

  /// Creates a [SourceSpan] from [spannable] in context of [currentElement].
  SourceSpan spanFromSpannable(Spannable spannable, Entity? currentElement) {
    return _elementMap.getSourceSpan(spannable, currentElement);
  }

  /// Creates the [TypesInferrer] used by this strategy.
  TypesInferrer createTypesInferrer(
    covariant JClosedWorld closedWorld,
    GlobalLocalsMap globalLocalsMap,
    InferredDataBuilder inferredDataBuilder,
  ) {
    return TypeGraphInferrer(
      _compiler,
      closedWorld,
      globalLocalsMap,
      inferredDataBuilder,
    );
  }

  /// Prepare [source] to deserialize modular code generation data.
  void prepareCodegenReader(DataSourceReader source) {
    source.registerComponentLookup(
      ComponentLookup(_elementMap.programEnv.mainComponent),
    );
  }

  /// Calls [f] for every member that needs to be serialized for modular code
  /// generation and returns an [EntityWriter] for encoding these members in
  /// the serialized data.
  ///
  /// The needed members include members computed on demand during non-modular
  /// code generation, such as constructor bodies and generator bodies.
  List<MemberEntity> forEachCodegenMember(
    void Function(MemberEntity member) f,
  ) {
    final lazyMemberBodies = _elementMap.prepareForCodegenSerialization();
    _elementMap.members.forEach((MemberEntity member, _) {
      if (member.isAbstract) return;
      f(member);
    });
    return lazyMemberBodies;
  }
}

class KernelCodegenWorkItemBuilder implements WorkItemBuilder {
  final JsBackendStrategy _backendStrategy;
  final AbstractValueDomain _abstractValueDomain;
  final CodegenResults _codegenResults;
  final ComponentLookup _componentLookup;
  final SourceLookup _sourceLookup;

  KernelCodegenWorkItemBuilder(
    this._backendStrategy,
    this._abstractValueDomain,
    this._codegenResults,
    this._componentLookup,
    this._sourceLookup,
  );

  @override
  WorkItem? createWorkItem(MemberEntity entity) {
    if (entity.isAbstract) return null;
    return KernelCodegenWorkItem(
      _backendStrategy,
      _abstractValueDomain,
      _codegenResults,
      _componentLookup,
      _sourceLookup,
      entity,
    );
  }
}

class KernelCodegenWorkItem extends WorkItem {
  final JsBackendStrategy _backendStrategy;
  final AbstractValueDomain _abstractValueDomain;
  final CodegenResults _codegenResults;
  final ComponentLookup _componentLookup;
  final SourceLookup _sourceLookup;
  @override
  final MemberEntity element;

  KernelCodegenWorkItem(
    this._backendStrategy,
    this._abstractValueDomain,
    this._codegenResults,
    this._componentLookup,
    this._sourceLookup,
    this.element,
  );

  @override
  WorldImpact run() {
    return _backendStrategy.generateCode(
      this,
      _abstractValueDomain,
      _codegenResults,
      _componentLookup,
      _sourceLookup,
    );
  }
}

/// Task for building SSA from kernel IR loaded from .dill.
class KernelSsaBuilder implements SsaBuilder {
  final CompilerTask _task;
  final CompilerOptions _options;
  final DiagnosticReporter _reporter;
  final DumpInfoTask _dumpInfoTask;
  final SsaMetrics _metrics;
  final JClosedWorld _closedWorld;
  final JsToElementMap _elementMap;
  final SourceInformationStrategy _sourceInformationStrategy;

  final FunctionInlineCache _inlineCache;
  final InlineDataCache _inlineDataCache;

  KernelSsaBuilder(
    this._task,
    this._options,
    this._reporter,
    this._dumpInfoTask,
    this._metrics,
    this._closedWorld,
    this._elementMap,
    this._sourceInformationStrategy,
  ) : _inlineCache = FunctionInlineCache(_closedWorld.annotationsData),
      _inlineDataCache = InlineDataCache(
        enableUserAssertions: _options.enableUserAssertions,
        omitImplicitCasts: _options.omitImplicitChecks,
      );

  @override
  HGraph? build(
    MemberEntity member,
    GlobalTypeInferenceResults results,
    CodegenInputs codegen,
    CodegenRegistry registry,
    ModularNamer namer,
    ModularEmitter emitter,
  ) {
    return _task.measure(() {
      KernelSsaGraphBuilder builder = KernelSsaGraphBuilder(
        _options,
        _reporter,
        member,
        _elementMap.getMemberThisType(member),
        _dumpInfoTask,
        _metrics,
        _elementMap,
        results,
        _closedWorld,
        registry,
        namer,
        emitter,
        codegen.tracer,
        _sourceInformationStrategy,
        _inlineCache,
        _inlineDataCache,
      );
      return builder.build();
    });
  }
}

class KernelToTypeInferenceMapImpl implements KernelToTypeInferenceMap {
  final GlobalTypeInferenceResults _globalInferenceResults;
  late final GlobalTypeInferenceMemberResult _targetResults;

  KernelToTypeInferenceMapImpl(
    MemberEntity target,
    this._globalInferenceResults,
  ) {
    _targetResults = _resultOf(target);
  }

  GlobalTypeInferenceMemberResult _resultOf(MemberEntity e) =>
      _globalInferenceResults.resultOfMember(
        e is ConstructorBodyEntity ? e.constructor : e,
      );

  @override
  AbstractValue getReturnTypeOf(FunctionEntity function) {
    return AbstractValueFactory.inferredReturnTypeForElement(
      function,
      _globalInferenceResults,
    );
  }

  @override
  AbstractValue? receiverTypeOfInvocation(
    ir.Expression node,
    AbstractValueDomain abstractValueDomain,
  ) {
    return _targetResults.typeOfReceiver(node);
  }

  @override
  AbstractValue? receiverTypeOfGet(ir.Expression node) {
    return _targetResults.typeOfReceiver(node);
  }

  @override
  AbstractValue? receiverTypeOfSet(
    ir.Expression node,
    AbstractValueDomain abstractValueDomain,
  ) {
    return _targetResults.typeOfReceiver(node);
  }

  @override
  AbstractValue typeOfListLiteral(
    ir.ListLiteral listLiteral,
    AbstractValueDomain abstractValueDomain,
  ) {
    return _globalInferenceResults.typeOfListLiteral(listLiteral) ??
        abstractValueDomain.dynamicType;
  }

  @override
  AbstractValue? typeOfRecordLiteral(
    ir.RecordLiteral recordLiteral,
    AbstractValueDomain abstractValueDomain,
  ) {
    return _globalInferenceResults.typeOfRecordLiteral(recordLiteral);
  }

  @override
  AbstractValue? typeOfIterator(ir.ForInStatement node) {
    return _targetResults.typeOfIterator(node);
  }

  @override
  AbstractValue? typeOfIteratorCurrent(ir.ForInStatement node) {
    return _targetResults.typeOfIteratorCurrent(node);
  }

  @override
  AbstractValue? typeOfIteratorMoveNext(ir.ForInStatement node) {
    return _targetResults.typeOfIteratorMoveNext(node);
  }

  @override
  bool isJsIndexableIterator(
    ir.ForInStatement node,
    AbstractValueDomain abstractValueDomain,
  ) {
    final mask = typeOfIterator(node);
    // TODO(sra): Investigate why mask is sometimes null.
    if (mask == null) return false;
    return abstractValueDomain.isJsIndexableAndIterable(mask).isDefinitelyTrue;
  }

  @override
  AbstractValue inferredIndexType(ir.ForInStatement node) {
    return AbstractValueFactory.inferredResultTypeForSelector(
      Selector.index(),
      typeOfIterator(node)!,
      _globalInferenceResults,
    );
  }

  @override
  AbstractValue getInferredTypeOf(MemberEntity member) {
    return AbstractValueFactory.inferredTypeForMember(
      member,
      _globalInferenceResults,
    );
  }

  @override
  AbstractValue getInferredTypeOfParameter(
    Local parameter,
    MemberEntity? member,
  ) {
    return AbstractValueFactory.inferredTypeForParameter(
      parameter,
      member,
      _globalInferenceResults,
    );
  }

  @override
  AbstractValue resultTypeOfSelector(Selector selector, AbstractValue mask) {
    return AbstractValueFactory.inferredResultTypeForSelector(
      selector,
      mask,
      _globalInferenceResults,
    );
  }

  @override
  AbstractValue typeFromNativeBehavior(
    NativeBehavior nativeBehavior,
    JClosedWorld closedWorld,
  ) {
    return AbstractValueFactory.fromNativeBehavior(nativeBehavior, closedWorld);
  }
}