// Copyright (c) 2019, the R8 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.
package com.android.tools.r8.shaking;

import static com.android.tools.r8.graph.DexEncodedMethod.asProgramMethodOrNull;
import static com.android.tools.r8.graph.DexProgramClass.asProgramClassOrNull;
import static com.android.tools.r8.graph.ResolutionResult.SingleResolutionResult.isOverriding;

import com.android.tools.r8.cf.CfVersion;
import com.android.tools.r8.features.ClassToFeatureSplitMap;
import com.android.tools.r8.graph.AppInfoWithClassHierarchy;
import com.android.tools.r8.graph.DexCallSite;
import com.android.tools.r8.graph.DexClass;
import com.android.tools.r8.graph.DexClassAndMethod;
import com.android.tools.r8.graph.DexClasspathClass;
import com.android.tools.r8.graph.DexDefinition;
import com.android.tools.r8.graph.DexDefinitionSupplier;
import com.android.tools.r8.graph.DexEncodedField;
import com.android.tools.r8.graph.DexEncodedMethod;
import com.android.tools.r8.graph.DexField;
import com.android.tools.r8.graph.DexMember;
import com.android.tools.r8.graph.DexMethod;
import com.android.tools.r8.graph.DexProgramClass;
import com.android.tools.r8.graph.DexReference;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.graph.DirectMappedDexApplication;
import com.android.tools.r8.graph.FieldAccessInfo;
import com.android.tools.r8.graph.FieldAccessInfoCollection;
import com.android.tools.r8.graph.FieldAccessInfoCollectionImpl;
import com.android.tools.r8.graph.FieldResolutionResult;
import com.android.tools.r8.graph.GraphLens.NonIdentityGraphLens;
import com.android.tools.r8.graph.InstantiatedSubTypeInfo;
import com.android.tools.r8.graph.LookupResult.LookupResultSuccess;
import com.android.tools.r8.graph.LookupTarget;
import com.android.tools.r8.graph.MethodAccessInfoCollection;
import com.android.tools.r8.graph.ObjectAllocationInfoCollection;
import com.android.tools.r8.graph.ObjectAllocationInfoCollectionImpl;
import com.android.tools.r8.graph.ProgramField;
import com.android.tools.r8.graph.ProgramMethod;
import com.android.tools.r8.graph.PrunedItems;
import com.android.tools.r8.graph.ResolutionResult.SingleResolutionResult;
import com.android.tools.r8.graph.SubtypingInfo;
import com.android.tools.r8.ir.analysis.type.ClassTypeElement;
import com.android.tools.r8.ir.code.Invoke.Type;
import com.android.tools.r8.ir.desugar.DesugaredLibraryAPIConverter;
import com.android.tools.r8.ir.desugar.InterfaceMethodRewriter;
import com.android.tools.r8.ir.desugar.LambdaDescriptor;
import com.android.tools.r8.ir.desugar.TwrCloseResourceRewriter;
import com.android.tools.r8.synthesis.CommittedItems;
import com.android.tools.r8.utils.CollectionUtils;
import com.android.tools.r8.utils.InternalOptions;
import com.android.tools.r8.utils.ListUtils;
import com.android.tools.r8.utils.PredicateSet;
import com.android.tools.r8.utils.TraversalContinuation;
import com.android.tools.r8.utils.Visibility;
import com.android.tools.r8.utils.WorkList;
import com.android.tools.r8.utils.collections.ProgramMethodSet;
import com.android.tools.r8.utils.structural.Ordered;
import com.google.common.collect.Sets;
import it.unimi.dsi.fastutil.ints.Int2ReferenceMap;
import it.unimi.dsi.fastutil.objects.Object2BooleanMap;
import java.util.ArrayDeque;
import java.util.Collection;
import java.util.Collections;
import java.util.Deque;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Consumer;
import java.util.stream.Collectors;

/** Encapsulates liveness and reachability information for an application. */
public class AppInfoWithLiveness extends AppInfoWithClassHierarchy
    implements InstantiatedSubTypeInfo {
  /** Set of reachable proto types that will be dead code eliminated. */
  private final Set<DexType> deadProtoTypes;
  /** Set of types that are mentioned in the program, but for which no definition exists. */
  private final Set<DexType> missingTypes;
  /**
   * Set of types that are mentioned in the program. We at least need an empty abstract classitem
   * for these.
   */
  private final Set<DexType> liveTypes;
  /**
   * Set of methods that are the immediate target of an invoke. They might not actually be live but
   * are required so that invokes can find the method. If such a method is not live (i.e. not
   * contained in {@link #liveMethods}, it may be marked as abstract and its implementation may be
   * removed.
   */
  private final Set<DexMethod> targetedMethods;

  /** Set of targets that lead to resolution errors, such as non-existing or invalid targets. */
  private final Set<DexMethod> failedResolutionTargets;

  /**
   * Set of program methods that are used as the bootstrap method for an invoke-dynamic instruction.
   */
  private final Set<DexMethod> bootstrapMethods;

  /** Set of methods that are the immediate target of an invoke-dynamic. */
  private final Set<DexMethod> methodsTargetedByInvokeDynamic;
  /** Set of virtual methods that are the immediate target of an invoke-direct. */
  private final Set<DexMethod> virtualMethodsTargetedByInvokeDirect;
  /**
   * Set of methods that belong to live classes and can be reached by invokes. These need to be
   * kept.
   */
  private final Set<DexMethod> liveMethods;
  /**
   * Information about all fields that are accessed by the program. The information includes whether
   * a given field is read/written by the program, and it also includes all indirect accesses to
   * each field. The latter is used, for example, during member rebinding.
   */
  private FieldAccessInfoCollectionImpl fieldAccessInfoCollection;
  /** Set of all methods referenced in invokes along with their calling contexts. */
  private final MethodAccessInfoCollection methodAccessInfoCollection;
  /** Information about instantiated classes and their allocation sites. */
  private final ObjectAllocationInfoCollectionImpl objectAllocationInfoCollection;
  /**
   * Set of live call sites in the code. Note that if desugaring has taken place call site objects
   * will have been removed from the code.
   */
  public final Map<DexCallSite, ProgramMethodSet> callSites;
  /** Collection of keep requirements for the program. */
  private final KeepInfoCollection keepInfo;
  /** All items with assumemayhavesideeffects rule. */
  public final Map<DexReference, ProguardMemberRule> mayHaveSideEffects;
  /** All items with assumenosideeffects rule. */
  public final Map<DexMember<?, ?>, ProguardMemberRule> noSideEffects;
  /** All items with assumevalues rule. */
  public final Map<DexMember<?, ?>, ProguardMemberRule> assumedValues;
  /** All methods that should be inlined if possible due to a configuration directive. */
  private final Set<DexMethod> alwaysInline;
  /** All methods that *must* be inlined due to a configuration directive (testing only). */
  private final Set<DexMethod> forceInline;
  /** All methods that *must* never be inlined due to a configuration directive (testing only). */
  private final Set<DexMethod> neverInline;
  /** Items for which to print inlining decisions for (testing only). */
  private final Set<DexMethod> whyAreYouNotInlining;
  /** All methods that may not have any parameters with a constant value removed. */
  private final Set<DexMethod> keepConstantArguments;
  /** All methods that may not have any unused arguments removed. */
  private final Set<DexMethod> keepUnusedArguments;
  /** All methods that must be reprocessed (testing only). */
  private final Set<DexMethod> reprocess;
  /** All methods that must not be reprocessed (testing only). */
  private final Set<DexMethod> neverReprocess;
  /** All types that should be inlined if possible due to a configuration directive. */
  public final PredicateSet<DexType> alwaysClassInline;
  /** All types that *must* never be inlined due to a configuration directive (testing only). */
  private final Set<DexType> neverClassInline;

  private final Set<DexType> noClassMerging;
  private final Set<DexType> noHorizontalClassMerging;
  private final Set<DexType> noVerticalClassMerging;
  private final Set<DexType> noStaticClassMerging;

  /**
   * Set of lock candidates (i.e., types whose class reference may flow to a monitor instruction).
   */
  private final Set<DexType> lockCandidates;
  /**
   * A map from seen init-class references to the minimum required visibility of the corresponding
   * static field.
   */
  public final Map<DexType, Visibility> initClassReferences;
  /**
   * All methods and fields whose value *must* never be propagated due to a configuration directive.
   * (testing only).
   */
  private final Set<DexReference> neverPropagateValue;
  /**
   * All items with -identifiernamestring rule. Bound boolean value indicates the rule is explicitly
   * specified by users (<code>true</code>) or not, i.e., implicitly added by R8 (<code>false</code>
   * ).
   */
  public final Object2BooleanMap<DexReference> identifierNameStrings;
  /** A set of types that have been removed by the {@link TreePruner}. */
  final Set<DexType> prunedTypes;
  /** A map from switchmap class types to their corresponding switchmaps. */
  final Map<DexField, Int2ReferenceMap<DexField>> switchMaps;

  /* A cache to improve the lookup performance of lookupSingleVirtualTarget */
  private final SingleTargetLookupCache singleTargetLookupCache = new SingleTargetLookupCache();

  // TODO(zerny): Clean up the constructors so we have just one.
  AppInfoWithLiveness(
      CommittedItems syntheticItems,
      ClassToFeatureSplitMap classToFeatureSplitMap,
      MainDexClasses mainDexClasses,
      Set<DexType> deadProtoTypes,
      Set<DexType> missingTypes,
      Set<DexType> liveTypes,
      Set<DexMethod> targetedMethods,
      Set<DexMethod> failedResolutionTargets,
      Set<DexMethod> bootstrapMethods,
      Set<DexMethod> methodsTargetedByInvokeDynamic,
      Set<DexMethod> virtualMethodsTargetedByInvokeDirect,
      Set<DexMethod> liveMethods,
      FieldAccessInfoCollectionImpl fieldAccessInfoCollection,
      MethodAccessInfoCollection methodAccessInfoCollection,
      ObjectAllocationInfoCollectionImpl objectAllocationInfoCollection,
      Map<DexCallSite, ProgramMethodSet> callSites,
      KeepInfoCollection keepInfo,
      Map<DexReference, ProguardMemberRule> mayHaveSideEffects,
      Map<DexMember<?, ?>, ProguardMemberRule> noSideEffects,
      Map<DexMember<?, ?>, ProguardMemberRule> assumedValues,
      Set<DexMethod> alwaysInline,
      Set<DexMethod> forceInline,
      Set<DexMethod> neverInline,
      Set<DexMethod> whyAreYouNotInlining,
      Set<DexMethod> keepConstantArguments,
      Set<DexMethod> keepUnusedArguments,
      Set<DexMethod> reprocess,
      Set<DexMethod> neverReprocess,
      PredicateSet<DexType> alwaysClassInline,
      Set<DexType> neverClassInline,
      Set<DexType> noClassMerging,
      Set<DexType> noVerticalClassMerging,
      Set<DexType> noHorizontalClassMerging,
      Set<DexType> noStaticClassMerging,
      Set<DexReference> neverPropagateValue,
      Object2BooleanMap<DexReference> identifierNameStrings,
      Set<DexType> prunedTypes,
      Map<DexField, Int2ReferenceMap<DexField>> switchMaps,
      Set<DexType> lockCandidates,
      Map<DexType, Visibility> initClassReferences) {
    super(syntheticItems, classToFeatureSplitMap, mainDexClasses);
    this.deadProtoTypes = deadProtoTypes;
    this.missingTypes = missingTypes;
    this.liveTypes = liveTypes;
    this.targetedMethods = targetedMethods;
    this.failedResolutionTargets = failedResolutionTargets;
    this.bootstrapMethods = bootstrapMethods;
    this.methodsTargetedByInvokeDynamic = methodsTargetedByInvokeDynamic;
    this.virtualMethodsTargetedByInvokeDirect = virtualMethodsTargetedByInvokeDirect;
    this.liveMethods = liveMethods;
    this.fieldAccessInfoCollection = fieldAccessInfoCollection;
    this.methodAccessInfoCollection = methodAccessInfoCollection;
    this.objectAllocationInfoCollection = objectAllocationInfoCollection;
    this.keepInfo = keepInfo;
    this.mayHaveSideEffects = mayHaveSideEffects;
    this.noSideEffects = noSideEffects;
    this.assumedValues = assumedValues;
    this.callSites = callSites;
    this.alwaysInline = alwaysInline;
    this.forceInline = forceInline;
    this.neverInline = neverInline;
    this.whyAreYouNotInlining = whyAreYouNotInlining;
    this.keepConstantArguments = keepConstantArguments;
    this.keepUnusedArguments = keepUnusedArguments;
    this.reprocess = reprocess;
    this.neverReprocess = neverReprocess;
    this.alwaysClassInline = alwaysClassInline;
    this.neverClassInline = neverClassInline;
    this.noClassMerging = noClassMerging;
    this.noVerticalClassMerging = noVerticalClassMerging;
    this.noHorizontalClassMerging = noHorizontalClassMerging;
    this.noStaticClassMerging = noStaticClassMerging;
    this.neverPropagateValue = neverPropagateValue;
    this.identifierNameStrings = identifierNameStrings;
    this.prunedTypes = prunedTypes;
    this.switchMaps = switchMaps;
    this.lockCandidates = lockCandidates;
    this.initClassReferences = initClassReferences;
    verify();
  }

  private AppInfoWithLiveness(
      AppInfoWithLiveness previous, CommittedItems committedItems, Set<DexType> removedTypes) {
    this(
        committedItems,
        previous.getClassToFeatureSplitMap(),
        previous.getMainDexClasses(),
        previous.deadProtoTypes,
        previous.missingTypes,
        CollectionUtils.mergeSets(
            Sets.difference(previous.liveTypes, removedTypes), committedItems.getCommittedTypes()),
        previous.targetedMethods,
        previous.failedResolutionTargets,
        previous.bootstrapMethods,
        previous.methodsTargetedByInvokeDynamic,
        previous.virtualMethodsTargetedByInvokeDirect,
        previous.liveMethods,
        previous.fieldAccessInfoCollection,
        previous.methodAccessInfoCollection,
        previous.objectAllocationInfoCollection,
        previous.callSites,
        previous.keepInfo,
        previous.mayHaveSideEffects,
        previous.noSideEffects,
        previous.assumedValues,
        previous.alwaysInline,
        previous.forceInline,
        previous.neverInline,
        previous.whyAreYouNotInlining,
        previous.keepConstantArguments,
        previous.keepUnusedArguments,
        previous.reprocess,
        previous.neverReprocess,
        previous.alwaysClassInline,
        previous.neverClassInline,
        previous.noClassMerging,
        previous.noVerticalClassMerging,
        previous.noHorizontalClassMerging,
        previous.noStaticClassMerging,
        previous.neverPropagateValue,
        previous.identifierNameStrings,
        previous.prunedTypes,
        previous.switchMaps,
        previous.lockCandidates,
        previous.initClassReferences);
  }

  private AppInfoWithLiveness(AppInfoWithLiveness previous, PrunedItems prunedItems) {
    this(
        previous.getSyntheticItems().commitPrunedItems(prunedItems),
        previous.getClassToFeatureSplitMap().withoutPrunedItems(prunedItems),
        previous.getMainDexClasses().withoutPrunedItems(prunedItems),
        previous.deadProtoTypes,
        previous.missingTypes,
        prunedItems.hasRemovedClasses()
            ? Sets.difference(previous.liveTypes, prunedItems.getRemovedClasses())
            : previous.liveTypes,
        previous.targetedMethods,
        previous.failedResolutionTargets,
        previous.bootstrapMethods,
        previous.methodsTargetedByInvokeDynamic,
        previous.virtualMethodsTargetedByInvokeDirect,
        previous.liveMethods,
        previous.fieldAccessInfoCollection,
        previous.methodAccessInfoCollection,
        previous.objectAllocationInfoCollection,
        previous.callSites,
        extendPinnedItems(previous, prunedItems.getAdditionalPinnedItems()),
        previous.mayHaveSideEffects,
        previous.noSideEffects,
        previous.assumedValues,
        previous.alwaysInline,
        previous.forceInline,
        previous.neverInline,
        previous.whyAreYouNotInlining,
        previous.keepConstantArguments,
        previous.keepUnusedArguments,
        previous.reprocess,
        previous.neverReprocess,
        previous.alwaysClassInline,
        previous.neverClassInline,
        previous.noClassMerging,
        previous.noVerticalClassMerging,
        previous.noHorizontalClassMerging,
        previous.noStaticClassMerging,
        previous.neverPropagateValue,
        previous.identifierNameStrings,
        prunedItems.hasRemovedClasses()
            ? CollectionUtils.mergeSets(previous.prunedTypes, prunedItems.getRemovedClasses())
            : previous.prunedTypes,
        previous.switchMaps,
        previous.lockCandidates,
        previous.initClassReferences);
  }

  private void verify() {
    assert keepInfo.verifyPinnedTypesAreLive(liveTypes);
    assert objectAllocationInfoCollection.verifyAllocatedTypesAreLive(liveTypes, this);
  }

  private static KeepInfoCollection extendPinnedItems(
      AppInfoWithLiveness previous, Collection<? extends DexReference> additionalPinnedItems) {
    if (additionalPinnedItems == null || additionalPinnedItems.isEmpty()) {
      return previous.keepInfo;
    }
    return previous.keepInfo.mutate(
        collection -> {
          for (DexReference reference : additionalPinnedItems) {
            if (reference.isDexType()) {
              DexProgramClass clazz =
                  asProgramClassOrNull(previous.definitionFor(reference.asDexType()));
              if (clazz != null) {
                collection.pinClass(clazz);
              }
            } else if (reference.isDexMethod()) {
              DexMethod method = reference.asDexMethod();
              DexProgramClass clazz = asProgramClassOrNull(previous.definitionFor(method.holder));
              if (clazz != null) {
                ProgramMethod definition = clazz.lookupProgramMethod(method);
                if (definition != null) {
                  collection.pinMethod(definition);
                }
              }
            } else {
              DexField field = reference.asDexField();
              DexProgramClass clazz = asProgramClassOrNull(previous.definitionFor(field.holder));
              if (clazz != null) {
                ProgramField definition = clazz.lookupProgramField(field);
                if (definition != null) {
                  collection.pinField(definition);
                }
              }
            }
          }
        });
  }

  public AppInfoWithLiveness(
      AppInfoWithLiveness previous, Map<DexField, Int2ReferenceMap<DexField>> switchMaps) {
    super(
        previous.getSyntheticItems().commit(previous.app()),
        previous.getClassToFeatureSplitMap(),
        previous.getMainDexClasses());
    this.deadProtoTypes = previous.deadProtoTypes;
    this.missingTypes = previous.missingTypes;
    this.liveTypes = previous.liveTypes;
    this.targetedMethods = previous.targetedMethods;
    this.failedResolutionTargets = previous.failedResolutionTargets;
    this.bootstrapMethods = previous.bootstrapMethods;
    this.methodsTargetedByInvokeDynamic = previous.methodsTargetedByInvokeDynamic;
    this.virtualMethodsTargetedByInvokeDirect = previous.virtualMethodsTargetedByInvokeDirect;
    this.liveMethods = previous.liveMethods;
    this.fieldAccessInfoCollection = previous.fieldAccessInfoCollection;
    this.methodAccessInfoCollection = previous.methodAccessInfoCollection;
    this.objectAllocationInfoCollection = previous.objectAllocationInfoCollection;
    this.keepInfo = previous.keepInfo;
    this.mayHaveSideEffects = previous.mayHaveSideEffects;
    this.noSideEffects = previous.noSideEffects;
    this.assumedValues = previous.assumedValues;
    this.callSites = previous.callSites;
    this.alwaysInline = previous.alwaysInline;
    this.forceInline = previous.forceInline;
    this.neverInline = previous.neverInline;
    this.whyAreYouNotInlining = previous.whyAreYouNotInlining;
    this.keepConstantArguments = previous.keepConstantArguments;
    this.keepUnusedArguments = previous.keepUnusedArguments;
    this.reprocess = previous.reprocess;
    this.neverReprocess = previous.neverReprocess;
    this.alwaysClassInline = previous.alwaysClassInline;
    this.neverClassInline = previous.neverClassInline;
    this.noClassMerging = previous.noClassMerging;
    this.noVerticalClassMerging = previous.noVerticalClassMerging;
    this.noHorizontalClassMerging = previous.noHorizontalClassMerging;
    this.noStaticClassMerging = previous.noStaticClassMerging;
    this.neverPropagateValue = previous.neverPropagateValue;
    this.identifierNameStrings = previous.identifierNameStrings;
    this.prunedTypes = previous.prunedTypes;
    this.switchMaps = switchMaps;
    this.lockCandidates = previous.lockCandidates;
    this.initClassReferences = previous.initClassReferences;
    previous.markObsolete();
    verify();
  }

  public static AppInfoWithLivenessModifier modifier() {
    return new AppInfoWithLivenessModifier();
  }

  @Override
  public DexClass definitionFor(DexType type) {
    DexClass definition = super.definitionFor(type);
    assert definition != null
            || deadProtoTypes.contains(type)
            || missingTypes.contains(type)
            // TODO(b/150693139): Remove these exceptions once fixed.
            || InterfaceMethodRewriter.isCompanionClassType(type)
            || InterfaceMethodRewriter.hasDispatchClassSuffix(type)
            || InterfaceMethodRewriter.isEmulatedLibraryClassType(type)
            || type.toDescriptorString().startsWith("Lj$/$r8$retargetLibraryMember$")
            || TwrCloseResourceRewriter.isUtilityClassDescriptor(type)
            // TODO(b/150736225): Not sure how to remove these.
            || DesugaredLibraryAPIConverter.isVivifiedType(type)
        : "Failed lookup of non-missing type: " + type;
    return definition;
  }

  private CfVersion largestInputCfVersion = null;

  public boolean canUseConstClassInstructions(InternalOptions options) {
    if (!options.isGeneratingClassFiles()) {
      return true;
    }
    if (largestInputCfVersion == null) {
      computeLargestCfVersion();
    }
    return options.canUseConstClassInstructions(largestInputCfVersion);
  }

  private synchronized void computeLargestCfVersion() {
    if (largestInputCfVersion != null) {
      return;
    }
    for (DexProgramClass clazz : classes()) {
      // Skip synthetic classes which may not have a specified version.
      if (clazz.hasClassFileVersion()) {
        largestInputCfVersion =
            Ordered.maxIgnoreNull(largestInputCfVersion, clazz.getInitialClassFileVersion());
      }
    }
    assert largestInputCfVersion != null;
  }

  public boolean isLiveProgramClass(DexProgramClass clazz) {
    return liveTypes.contains(clazz.type);
  }

  public boolean isLiveProgramType(DexType type) {
    DexClass clazz = definitionFor(type);
    return clazz != null && clazz.isProgramClass() && isLiveProgramClass(clazz.asProgramClass());
  }

  public boolean isNonProgramTypeOrLiveProgramType(DexType type) {
    if (liveTypes.contains(type)) {
      return true;
    }
    if (prunedTypes.contains(type)) {
      return false;
    }
    DexClass clazz = definitionFor(type);
    return clazz == null || !clazz.isProgramClass();
  }

  public boolean isLiveMethod(DexMethod method) {
    return liveMethods.contains(method);
  }

  public boolean isTargetedMethod(DexMethod method) {
    return targetedMethods.contains(method);
  }

  public boolean isFailedResolutionTarget(DexMethod method) {
    return failedResolutionTargets.contains(method);
  }

  public Set<DexMethod> getFailedResolutionTargets() {
    return failedResolutionTargets;
  }

  public boolean isBootstrapMethod(DexMethod method) {
    return bootstrapMethods.contains(method);
  }

  public boolean isMethodTargetedByInvokeDynamic(DexMethod method) {
    return methodsTargetedByInvokeDynamic.contains(method);
  }

  public Set<DexMethod> getVirtualMethodsTargetedByInvokeDirect() {
    return virtualMethodsTargetedByInvokeDirect;
  }

  public boolean isAlwaysInlineMethod(DexMethod method) {
    return alwaysInline.contains(method);
  }

  public boolean hasNoAlwaysInlineMethods() {
    return alwaysInline.isEmpty();
  }

  public boolean isForceInlineMethod(DexMethod method) {
    return forceInline.contains(method);
  }

  public boolean hasNoForceInlineMethods() {
    return forceInline.isEmpty();
  }

  public boolean isNeverInlineMethod(DexMethod method) {
    return neverInline.contains(method);
  }

  public boolean isWhyAreYouNotInliningMethod(DexMethod method) {
    return whyAreYouNotInlining.contains(method);
  }

  public boolean hasNoWhyAreYouNotInliningMethods() {
    return whyAreYouNotInlining.isEmpty();
  }

  public boolean isKeepConstantArgumentsMethod(DexMethod method) {
    return keepConstantArguments.contains(method);
  }

  public boolean isKeepUnusedArgumentsMethod(DexMethod method) {
    return keepUnusedArguments.contains(method);
  }

  public boolean isNeverReprocessMethod(DexMethod method) {
    return neverReprocess.contains(method);
  }

  public Set<DexMethod> getReprocessMethods() {
    return reprocess;
  }

  public Collection<DexClass> computeReachableInterfaces() {
    Set<DexClass> interfaces = Sets.newIdentityHashSet();
    WorkList<DexType> worklist = WorkList.newIdentityWorkList();
    worklist.addIfNotSeen(objectAllocationInfoCollection.getInstantiatedLambdaInterfaces());
    for (DexProgramClass clazz : classes()) {
      worklist.addIfNotSeen(clazz.type);
    }
    while (worklist.hasNext()) {
      DexType type = worklist.next();
      DexClass definition = definitionFor(type);
      if (definition == null) {
        continue;
      }
      if (definition.isInterface()) {
        interfaces.add(definition);
      }
      if (definition.superType != null) {
        worklist.addIfNotSeen(definition.superType);
      }
      worklist.addIfNotSeen(definition.interfaces.values);
    }
    return interfaces;
  }

  /**
   * Resolve the methods implemented by the lambda expression that created the {@code callSite}.
   *
   * <p>If {@code callSite} was not created as a result of a lambda expression (i.e. the metafactory
   * is not {@code LambdaMetafactory}), the empty set is returned.
   *
   * <p>If the metafactory is neither {@code LambdaMetafactory} nor {@code StringConcatFactory}, a
   * warning is issued.
   *
   * <p>The returned set of methods all have {@code callSite.methodName} as the method name.
   *
   * @param callSite Call site to resolve.
   * @return Methods implemented by the lambda expression that created the {@code callSite}.
   */
  public Set<DexEncodedMethod> lookupLambdaImplementedMethods(DexCallSite callSite) {
    assert checkIfObsolete();
    List<DexType> callSiteInterfaces = LambdaDescriptor.getInterfaces(callSite, this);
    if (callSiteInterfaces == null || callSiteInterfaces.isEmpty()) {
      return Collections.emptySet();
    }
    Set<DexEncodedMethod> result = Sets.newIdentityHashSet();
    Deque<DexType> worklist = new ArrayDeque<>(callSiteInterfaces);
    Set<DexType> visited = Sets.newIdentityHashSet();
    while (!worklist.isEmpty()) {
      DexType iface = worklist.removeFirst();
      if (!visited.add(iface)) {
        // Already visited previously. May happen due to "diamond shapes" in the interface
        // hierarchy.
        continue;
      }
      DexClass clazz = definitionFor(iface);
      if (clazz == null) {
        // Skip this interface. If the lambda only implements missing library interfaces and not any
        // program interfaces, then minification and tree shaking are not interested in this
        // DexCallSite anyway, so skipping this interface is harmless. On the other hand, if
        // minification is run on a program with a lambda interface that implements both a missing
        // library interface and a present program interface, then we might minify the method name
        // on the program interface even though it should be kept the same as the (missing) library
        // interface method. That is a shame, but minification is not suited for incomplete programs
        // anyway.
        continue;
      }
      assert clazz.isInterface();
      for (DexEncodedMethod method : clazz.virtualMethods()) {
        if (method.method.name == callSite.methodName && method.accessFlags.isAbstract()) {
          result.add(method);
        }
      }
      Collections.addAll(worklist, clazz.interfaces.values);
    }
    return result;
  }

  /**
   * Const-classes is a conservative set of types that may be lock-candidates and cannot be merged.
   * When using synchronized blocks, we cannot ensure that const-class locks will not flow in. This
   * can potentially cause incorrect behavior when merging classes. A conservative choice is to not
   * merge any const-class classes. More info at b/142438687.
   */
  public boolean isLockCandidate(DexType type) {
    return lockCandidates.contains(type);
  }

  public Set<DexType> getDeadProtoTypes() {
    return deadProtoTypes;
  }

  public Set<DexType> getMissingTypes() {
    return missingTypes;
  }

  public Int2ReferenceMap<DexField> getSwitchMap(DexField field) {
    assert checkIfObsolete();
    return switchMaps.get(field);
  }

  /** This method provides immutable access to `fieldAccessInfoCollection`. */
  public FieldAccessInfoCollection<? extends FieldAccessInfo> getFieldAccessInfoCollection() {
    return fieldAccessInfoCollection;
  }

  FieldAccessInfoCollectionImpl getMutableFieldAccessInfoCollection() {
    return fieldAccessInfoCollection;
  }

  /** This method provides immutable access to `methodAccessInfoCollection`. */
  public MethodAccessInfoCollection getMethodAccessInfoCollection() {
    return methodAccessInfoCollection;
  }

  /** This method provides immutable access to `objectAllocationInfoCollection`. */
  public ObjectAllocationInfoCollection getObjectAllocationInfoCollection() {
    return objectAllocationInfoCollection;
  }

  void mutateObjectAllocationInfoCollection(
      Consumer<ObjectAllocationInfoCollectionImpl.Builder> mutator) {
    objectAllocationInfoCollection.mutate(mutator, this);
  }

  void removeFromSingleTargetLookupCache(DexClass clazz) {
    singleTargetLookupCache.removeInstantiatedType(clazz.type, this);
  }

  private boolean isInstantiatedDirectly(DexProgramClass clazz) {
    assert checkIfObsolete();
    DexType type = clazz.type;
    return
    // TODO(b/165224388): Synthetic classes should be represented in the allocation info.
    getSyntheticItems().isSyntheticClass(clazz)
        || (!clazz.isInterface() && objectAllocationInfoCollection.isInstantiatedDirectly(clazz))
        // TODO(b/145344105): Model annotations in the object allocation info.
        || (clazz.isAnnotation() && liveTypes.contains(type));
  }

  public boolean isInstantiatedIndirectly(DexProgramClass clazz) {
    assert checkIfObsolete();
    return objectAllocationInfoCollection.hasInstantiatedStrictSubtype(clazz);
  }

  public boolean isInstantiatedDirectlyOrIndirectly(DexProgramClass clazz) {
    assert checkIfObsolete();
    return isInstantiatedDirectly(clazz) || isInstantiatedIndirectly(clazz);
  }

  public boolean isFieldRead(DexEncodedField encodedField) {
    assert checkIfObsolete();
    DexField field = encodedField.field;
    FieldAccessInfo info = getFieldAccessInfoCollection().get(field);
    if (info != null && info.isRead()) {
      return true;
    }
    if (keepInfo.isPinned(field, this)) {
      return true;
    }
    // Fields in the class that is synthesized by D8/R8 would be used soon.
    // TODO(b/165229577): Do we need this special handling of synthetics?
    if (getSyntheticItems().isSyntheticClass(field.holder)) {
      return true;
    }
    // For library classes we don't know whether a field is read.
    return isLibraryOrClasspathField(encodedField);
  }

  public boolean isFieldWritten(DexEncodedField encodedField) {
    assert checkIfObsolete();
    return isFieldWrittenByFieldPutInstruction(encodedField) || isPinned(encodedField.field);
  }

  public boolean isFieldWrittenByFieldPutInstruction(DexEncodedField encodedField) {
    assert checkIfObsolete();
    DexField field = encodedField.field;
    FieldAccessInfo info = getFieldAccessInfoCollection().get(field);
    if (info != null && info.isWritten()) {
      // The field is written directly by the program itself.
      return true;
    }
    // TODO(b/165229577): Do we need this special handling of synthetics?
    if (getSyntheticItems().isSyntheticClass(field.holder)) {
      return true;
    }
    // For library classes we don't know whether a field is rewritten.
    return isLibraryOrClasspathField(encodedField);
  }

  public boolean isFieldOnlyWrittenInMethod(DexEncodedField field, DexEncodedMethod method) {
    assert checkIfObsolete();
    assert isFieldWritten(field) : "Expected field `" + field.toSourceString() + "` to be written";
    if (isPinned(field.field)) {
      return false;
    }
    return isFieldOnlyWrittenInMethodIgnoringPinning(field, method);
  }

  public boolean isFieldOnlyWrittenInMethodIgnoringPinning(
      DexEncodedField field, DexEncodedMethod method) {
    assert checkIfObsolete();
    assert isFieldWritten(field) : "Expected field `" + field.toSourceString() + "` to be written";
    FieldAccessInfo fieldAccessInfo = getFieldAccessInfoCollection().get(field.field);
    return fieldAccessInfo != null
        && fieldAccessInfo.isWritten()
        && !fieldAccessInfo.isWrittenOutside(method);
  }

  public boolean isInstanceFieldWrittenOnlyInInstanceInitializers(DexEncodedField field) {
    assert checkIfObsolete();
    assert isFieldWritten(field) : "Expected field `" + field.toSourceString() + "` to be written";
    if (isPinned(field.field)) {
      return false;
    }
    FieldAccessInfo fieldAccessInfo = getFieldAccessInfoCollection().get(field.field);
    if (fieldAccessInfo == null || !fieldAccessInfo.isWritten()) {
      return false;
    }
    DexType holder = field.getHolderType();
    return fieldAccessInfo.isWrittenOnlyInMethodSatisfying(
        method ->
            method.getHolderType() == holder
                && method
                    .getDefinition()
                    .isOrWillBeInlinedIntoInstanceInitializer(dexItemFactory()));
  }

  public boolean isStaticFieldWrittenOnlyInEnclosingStaticInitializer(DexEncodedField field) {
    assert checkIfObsolete();
    assert isFieldWritten(field) : "Expected field `" + field.toSourceString() + "` to be written";
    DexEncodedMethod staticInitializer =
        definitionFor(field.getHolderType()).asProgramClass().getClassInitializer();
    return staticInitializer != null && isFieldOnlyWrittenInMethod(field, staticInitializer);
  }

  public boolean mayPropagateArgumentsTo(ProgramMethod method) {
    DexMethod reference = method.getReference();
    return method.getDefinition().hasCode()
        && !method.getDefinition().isLibraryMethodOverride().isPossiblyTrue()
        && !neverReprocess.contains(reference)
        && !keepInfo.getMethodInfo(method).isPinned();
  }

  public boolean mayPropagateValueFor(DexReference reference) {
    assert checkIfObsolete();
    return options().enableValuePropagation
        && !isPinned(reference)
        && !neverPropagateValue.contains(reference);
  }

  private boolean isLibraryOrClasspathField(DexEncodedField field) {
    DexClass holder = definitionFor(field.getHolderType());
    return holder == null || holder.isLibraryClass() || holder.isClasspathClass();
  }

  public boolean isInstantiatedInterface(DexProgramClass clazz) {
    assert checkIfObsolete();
    return objectAllocationInfoCollection.isInterfaceWithUnknownSubtypeHierarchy(clazz);
  }

  @Override
  public boolean hasLiveness() {
    assert checkIfObsolete();
    return true;
  }

  @Override
  public AppInfoWithLiveness withLiveness() {
    assert checkIfObsolete();
    return this;
  }

  public boolean isClassInliningAllowed(DexProgramClass clazz) {
    return !isPinned(clazz) && !neverClassInline.contains(clazz.getType());
  }

  public boolean isMinificationAllowed(DexReference reference) {
    return options().isMinificationEnabled()
        && keepInfo.getInfo(reference, this).isMinificationAllowed(options());
  }

  public boolean isAccessModificationAllowed(DexReference reference) {
    assert options().getProguardConfiguration().isAccessModificationAllowed();
    return keepInfo.getInfo(reference, this).isAccessModificationAllowed(options());
  }

  public boolean isRepackagingAllowed(DexProgramClass clazz) {
    if (!options().isRepackagingEnabled()) {
      return false;
    }
    if (!keepInfo.getInfo(clazz).isRepackagingAllowed(options())) {
      return false;
    }
    return clazz
        .traverseProgramMembers(
            member -> {
              if (keepInfo.getInfo(member).isRepackagingAllowed(options())) {
                return TraversalContinuation.CONTINUE;
              }
              return TraversalContinuation.BREAK;
            })
        .shouldContinue();
  }

  public boolean isPinned(DexReference reference) {
    assert checkIfObsolete();
    return keepInfo.isPinned(reference, this);
  }

  public boolean isPinned(DexDefinition definition) {
    assert definition != null;
    return isPinned(definition.getReference());
  }

  public boolean hasPinnedInstanceInitializer(DexType type) {
    assert type.isClassType();
    DexProgramClass clazz = asProgramClassOrNull(definitionFor(type));
    if (clazz != null) {
      for (DexEncodedMethod method : clazz.directMethods()) {
        if (method.isInstanceInitializer() && isPinned(method.method)) {
          return true;
        }
      }
    }
    return false;
  }

  public KeepInfoCollection getKeepInfo() {
    return keepInfo;
  }

  /**
   * Returns a copy of this AppInfoWithLiveness where the set of classes is pruned using the given
   * DexApplication object.
   */
  public AppInfoWithLiveness prunedCopyFrom(PrunedItems prunedItems) {
    assert checkIfObsolete();
    if (prunedItems.hasRemovedClasses()) {
      // Rebuild the hierarchy.
      objectAllocationInfoCollection.mutate(
          mutator -> mutator.removeAllocationsForPrunedItems(prunedItems), this);
      keepInfo.mutate(
          keepInfo -> keepInfo.removeKeepInfoForPrunedItems(prunedItems.getRemovedClasses()));
    }
    return new AppInfoWithLiveness(this, prunedItems);
  }

  public AppInfoWithLiveness rebuildWithLiveness(
      CommittedItems committedItems, Set<DexType> removedTypes) {
    return new AppInfoWithLiveness(this, committedItems, removedTypes);
  }

  public AppInfoWithLiveness rewrittenWithLens(
      DirectMappedDexApplication application, NonIdentityGraphLens lens) {
    assert checkIfObsolete();

    // Switchmap classes should never be affected by renaming.
    assert lens.assertDefinitionsNotModified(
        switchMaps.keySet().stream()
            .map(this::resolveField)
            .filter(FieldResolutionResult::isSuccessfulResolution)
            .map(FieldResolutionResult::getResolvedField)
            .collect(Collectors.toList()));

    CommittedItems committedItems = getSyntheticItems().commitRewrittenWithLens(application, lens);
    DexDefinitionSupplier definitionSupplier = application.getDefinitionsSupplier(committedItems);
    return new AppInfoWithLiveness(
        committedItems,
        getClassToFeatureSplitMap().rewrittenWithLens(lens),
        getMainDexClasses().rewrittenWithLens(lens),
        deadProtoTypes,
        missingTypes,
        lens.rewriteTypes(liveTypes),
        lens.rewriteMethods(targetedMethods),
        lens.rewriteMethods(failedResolutionTargets),
        lens.rewriteMethods(bootstrapMethods),
        lens.rewriteMethods(methodsTargetedByInvokeDynamic),
        lens.rewriteMethods(virtualMethodsTargetedByInvokeDirect),
        lens.rewriteMethods(liveMethods),
        fieldAccessInfoCollection.rewrittenWithLens(definitionSupplier, lens),
        methodAccessInfoCollection.rewrittenWithLens(definitionSupplier, lens),
        objectAllocationInfoCollection.rewrittenWithLens(definitionSupplier, lens),
        lens.rewriteCallSites(callSites, definitionSupplier),
        keepInfo.rewrite(lens, application.options),
        lens.rewriteReferenceKeys(mayHaveSideEffects),
        lens.rewriteReferenceKeys(noSideEffects),
        lens.rewriteReferenceKeys(assumedValues),
        lens.rewriteMethods(alwaysInline),
        lens.rewriteMethods(forceInline),
        lens.rewriteMethods(neverInline),
        lens.rewriteMethods(whyAreYouNotInlining),
        lens.rewriteMethods(keepConstantArguments),
        lens.rewriteMethods(keepUnusedArguments),
        lens.rewriteMethods(reprocess),
        lens.rewriteMethods(neverReprocess),
        alwaysClassInline.rewriteItems(lens::lookupType),
        lens.rewriteTypes(neverClassInline),
        lens.rewriteTypes(noClassMerging),
        lens.rewriteTypes(noVerticalClassMerging),
        lens.rewriteTypes(noHorizontalClassMerging),
        lens.rewriteTypes(noStaticClassMerging),
        lens.rewriteReferences(neverPropagateValue),
        lens.rewriteReferenceKeys(identifierNameStrings),
        // Don't rewrite pruned types - the removed types are identified by their original name.
        prunedTypes,
        lens.rewriteFieldKeys(switchMaps),
        lens.rewriteTypes(lockCandidates),
        lens.rewriteTypeKeys(initClassReferences));
  }

  /**
   * Returns true if the given type was part of the original program but has been removed during
   * tree shaking.
   */
  public boolean wasPruned(DexType type) {
    assert checkIfObsolete();
    return prunedTypes.contains(type);
  }

  public Set<DexType> getPrunedTypes() {
    assert checkIfObsolete();
    return prunedTypes;
  }

  public DexEncodedMethod lookupSingleTarget(
      Type type,
      DexMethod target,
      ProgramMethod context,
      LibraryModeledPredicate modeledPredicate) {
    assert checkIfObsolete();
    DexType holder = target.holder;
    if (!holder.isClassType()) {
      return null;
    }
    switch (type) {
      case VIRTUAL:
        return lookupSingleVirtualTarget(target, context, false, modeledPredicate);
      case INTERFACE:
        return lookupSingleVirtualTarget(target, context, true, modeledPredicate);
      case DIRECT:
        return lookupDirectTarget(target, context);
      case STATIC:
        return lookupStaticTarget(target, context);
      case SUPER:
        return lookupSuperTarget(target, context);
      default:
        return null;
    }
  }

  public ProgramMethod lookupSingleProgramTarget(
      Type type,
      DexMethod target,
      ProgramMethod context,
      LibraryModeledPredicate modeledPredicate) {
    return asProgramMethodOrNull(lookupSingleTarget(type, target, context, modeledPredicate), this);
  }

  /** For mapping invoke virtual instruction to single target method. */
  public DexEncodedMethod lookupSingleVirtualTarget(
      DexMethod method, ProgramMethod context, boolean isInterface) {
    assert checkIfObsolete();
    return lookupSingleVirtualTarget(
        method, context, isInterface, type -> false, method.holder, null);
  }

  /** For mapping invoke virtual instruction to single target method. */
  public DexEncodedMethod lookupSingleVirtualTarget(
      DexMethod method,
      ProgramMethod context,
      boolean isInterface,
      LibraryModeledPredicate modeledPredicate) {
    assert checkIfObsolete();
    return lookupSingleVirtualTarget(
        method, context, isInterface, modeledPredicate, method.holder, null);
  }

  public DexEncodedMethod lookupSingleVirtualTarget(
      DexMethod method,
      ProgramMethod context,
      boolean isInterface,
      LibraryModeledPredicate modeledPredicate,
      DexType refinedReceiverType,
      ClassTypeElement receiverLowerBoundType) {
    assert checkIfObsolete();
    assert refinedReceiverType != null;
    if (!refinedReceiverType.isClassType()) {
      // The refined receiver is not of class type and we will not be able to find a single target
      // (it is either primitive or array).
      return null;
    }
    DexClass initialResolutionHolder = definitionFor(method.holder);
    if (initialResolutionHolder == null || initialResolutionHolder.isInterface() != isInterface) {
      return null;
    }
    DexClass refinedReceiverClass = definitionFor(refinedReceiverType);
    if (refinedReceiverClass == null) {
      // The refined receiver is not defined in the program and we cannot determine the target.
      return null;
    }
    if (receiverLowerBoundType == null
        && singleTargetLookupCache.hasCachedItem(refinedReceiverType, method)) {
      DexEncodedMethod cachedItem =
          singleTargetLookupCache.getCachedItem(refinedReceiverType, method);
      return cachedItem;
    }
    SingleResolutionResult resolution =
        resolveMethodOn(initialResolutionHolder, method).asSingleResolution();
    if (resolution == null
        || resolution.isAccessibleForVirtualDispatchFrom(context.getHolder(), this).isFalse()) {
      return null;
    }
    // If the method is modeled, return the resolution.
    DexEncodedMethod resolvedMethod = resolution.getResolvedMethod();
    if (modeledPredicate.isModeled(resolution.getResolvedHolder().type)) {
      if (resolution.getResolvedHolder().isFinal()
          || (resolvedMethod.isFinal() && resolvedMethod.accessFlags.isPublic())) {
        singleTargetLookupCache.addToCache(refinedReceiverType, method, resolvedMethod);
        return resolvedMethod;
      }
    }
    DexEncodedMethod exactTarget =
        getMethodTargetFromExactRuntimeInformation(
            refinedReceiverType, receiverLowerBoundType, resolution, refinedReceiverClass);
    if (exactTarget != null) {
      // We are not caching single targets here because the cache does not include the
      // lower bound dimension.
      return exactTarget == DexEncodedMethod.SENTINEL ? null : exactTarget;
    }
    if (refinedReceiverClass.isNotProgramClass()) {
      // The refined receiver is not defined in the program and we cannot determine the target.
      singleTargetLookupCache.addToCache(refinedReceiverType, method, null);
      return null;
    }
    DexClass resolvedHolder = resolution.getResolvedHolder();
    // TODO(b/148769279): Disable lookup single target on lambda's for now.
    if (resolvedHolder.isInterface()
        && resolvedHolder.isProgramClass()
        && objectAllocationInfoCollection.isImmediateInterfaceOfInstantiatedLambda(
            resolvedHolder.asProgramClass())) {
      singleTargetLookupCache.addToCache(refinedReceiverType, method, null);
      return null;
    }
    DexEncodedMethod singleMethodTarget = null;
    DexProgramClass refinedLowerBound = null;
    if (receiverLowerBoundType != null) {
      DexClass refinedLowerBoundClass = definitionFor(receiverLowerBoundType.getClassType());
      if (refinedLowerBoundClass != null) {
        refinedLowerBound = refinedLowerBoundClass.asProgramClass();
        // TODO(b/154822960): Check if the lower bound is a subtype of the upper bound.
        if (refinedLowerBound != null && !isSubtype(refinedLowerBound.type, refinedReceiverType)) {
          refinedLowerBound = null;
        }
      }
    }
    LookupResultSuccess lookupResult =
        resolution
            .lookupVirtualDispatchTargets(
                context.getHolder(), this, refinedReceiverClass.asProgramClass(), refinedLowerBound)
            .asLookupResultSuccess();
    if (lookupResult != null && !lookupResult.isIncomplete()) {
      LookupTarget singleTarget = lookupResult.getSingleLookupTarget();
      if (singleTarget != null && singleTarget.isMethodTarget()) {
        singleMethodTarget = singleTarget.asMethodTarget().getDefinition();
      }
    }
    if (receiverLowerBoundType == null) {
      singleTargetLookupCache.addToCache(refinedReceiverType, method, singleMethodTarget);
    }
    return singleMethodTarget;
  }

  private DexEncodedMethod getMethodTargetFromExactRuntimeInformation(
      DexType refinedReceiverType,
      ClassTypeElement receiverLowerBoundType,
      SingleResolutionResult resolution,
      DexClass refinedReceiverClass) {
    // If the lower-bound on the receiver type is the same as the upper-bound, then we have exact
    // runtime type information. In this case, the invoke will dispatch to the resolution result
    // from the runtime type of the receiver.
    if (receiverLowerBoundType != null
        && receiverLowerBoundType.getClassType() == refinedReceiverType) {
      if (refinedReceiverClass.isProgramClass()) {
        DexClassAndMethod clazzAndMethod =
            resolution.lookupVirtualDispatchTarget(refinedReceiverClass.asProgramClass(), this);
        if (clazzAndMethod == null || isPinned(clazzAndMethod.getDefinition().method)) {
          // TODO(b/150640456): We should maybe only consider program methods.
          return DexEncodedMethod.SENTINEL;
        }
        return clazzAndMethod.getDefinition();
      } else {
        // TODO(b/150640456): We should maybe only consider program methods.
        // If we resolved to a method on the refined receiver in the library, then we report the
        // method as a single target as well. This is a bit iffy since the library could change
        // implementation, but we use this for library modelling.
        DexEncodedMethod resolvedMethod = resolution.getResolvedMethod();
        DexEncodedMethod targetOnReceiver =
            refinedReceiverClass.lookupVirtualMethod(resolvedMethod.method);
        if (targetOnReceiver != null && isOverriding(resolvedMethod, targetOnReceiver)) {
          return targetOnReceiver;
        }
        return DexEncodedMethod.SENTINEL;
      }
    }
    return null;
  }

  public AppInfoWithLiveness withSwitchMaps(Map<DexField, Int2ReferenceMap<DexField>> switchMaps) {
    assert checkIfObsolete();
    assert this.switchMaps.isEmpty();
    return new AppInfoWithLiveness(this, switchMaps);
  }

  /**
   * Visit all class definitions of classpath classes that are referenced in the compilation unit.
   *
   * <p>TODO(b/139464956): Only traverse the classpath types referenced from the live program.
   * Conservatively traces all classpath classes for now.
   */
  public void forEachReferencedClasspathClass(Consumer<DexClasspathClass> fn) {
    app().asDirect().classpathClasses().forEach(fn);
  }

  /**
   * Visits all class definitions that are a live program type or a type above it in the hierarchy.
   *
   * <p>Any given definition will be visited at most once. No guarantees are places on the order.
   */
  public void forEachTypeInHierarchyOfLiveProgramClasses(Consumer<DexClass> fn) {
    forEachTypeInHierarchyOfLiveProgramClasses(
        fn,
        ListUtils.map(liveTypes, t -> definitionFor(t).asProgramClass()),
        objectAllocationInfoCollection.getInstantiatedLambdaInterfaces(),
        this);
  }

  // Split in a static method so it can be used during construction.
  static void forEachTypeInHierarchyOfLiveProgramClasses(
      Consumer<DexClass> fn,
      Collection<DexProgramClass> liveProgramClasses,
      Set<DexType> lambdaInterfaces,
      AppInfoWithClassHierarchy appInfo) {
    Set<DexType> seen = Sets.newIdentityHashSet();
    liveProgramClasses.forEach(c -> seen.add(c.type));
    Deque<DexType> worklist = new ArrayDeque<>(lambdaInterfaces);
    for (DexProgramClass liveProgramClass : liveProgramClasses) {
      fn.accept(liveProgramClass);
      DexType superType = liveProgramClass.superType;
      if (superType != null && seen.add(superType)) {
        worklist.add(superType);
      }
      for (DexType iface : liveProgramClass.interfaces.values) {
        if (seen.add(iface)) {
          worklist.add(iface);
        }
      }
    }
    while (!worklist.isEmpty()) {
      DexType type = worklist.pop();
      DexClass clazz = appInfo.definitionFor(type);
      if (clazz != null) {
        fn.accept(clazz);
        if (clazz.superType != null && seen.add(clazz.superType)) {
          worklist.add(clazz.superType);
        }
        for (DexType iface : clazz.interfaces.values) {
          if (seen.add(iface)) {
            worklist.add(iface);
          }
        }
      }
    }
  }

  @Override
  public void forEachInstantiatedSubType(
      DexType type,
      Consumer<DexProgramClass> subTypeConsumer,
      Consumer<LambdaDescriptor> callSiteConsumer) {
    objectAllocationInfoCollection.forEachInstantiatedSubType(
        type, subTypeConsumer, callSiteConsumer, this);
  }

  public void forEachInstantiatedSubTypeInChain(
      DexProgramClass refinedReceiverUpperBound,
      DexProgramClass refinedReceiverLowerBound,
      Consumer<DexProgramClass> subTypeConsumer,
      Consumer<LambdaDescriptor> callSiteConsumer) {
    List<DexProgramClass> subTypes =
        computeProgramClassRelationChain(refinedReceiverLowerBound, refinedReceiverUpperBound);
    for (DexProgramClass subType : subTypes) {
      if (isInstantiatedOrPinned(subType)) {
        subTypeConsumer.accept(subType);
      }
    }
  }

  private boolean isInstantiatedOrPinned(DexProgramClass clazz) {
    return isInstantiatedDirectly(clazz) || isPinned(clazz.type) || isInstantiatedInterface(clazz);
  }

  public boolean isPinnedNotProgramOrLibraryOverride(DexDefinition definition) {
    if (isPinned(definition.getReference())) {
      return true;
    }
    if (definition.isDexEncodedMethod()) {
      DexEncodedMethod method = definition.asDexEncodedMethod();
      return !method.isProgramMethod(this) || method.isLibraryMethodOverride().isPossiblyTrue();
    }
    assert definition.isDexClass();
    DexClass clazz = definition.asDexClass();
    return clazz.isNotProgramClass() || isInstantiatedInterface(clazz.asProgramClass());
  }

  public SubtypingInfo computeSubtypingInfo() {
    return new SubtypingInfo(this);
  }

  public boolean mayHaveFinalizeMethodDirectlyOrIndirectly(ClassTypeElement type) {
    // Special case for java.lang.Object.
    if (type.getClassType() == dexItemFactory().objectType) {
      if (type.getInterfaces().isEmpty()) {
        // The type java.lang.Object could be any instantiated type. Assume a finalizer exists.
        return true;
      }
      for (DexType iface : type.getInterfaces()) {
        if (mayHaveFinalizer(iface)) {
          return true;
        }
      }
      return false;
    }
    return mayHaveFinalizer(type.getClassType());
  }

  private boolean mayHaveFinalizer(DexType type) {
    // A type may have an active finalizer if any derived instance has a finalizer.
    return objectAllocationInfoCollection
        .traverseInstantiatedSubtypes(
            type,
            clazz -> {
              if (objectAllocationInfoCollection.isInterfaceWithUnknownSubtypeHierarchy(clazz)) {
                return TraversalContinuation.BREAK;
              } else {
                SingleResolutionResult resolution =
                    resolveMethodOn(clazz, dexItemFactory().objectMembers.finalize)
                        .asSingleResolution();
                if (resolution != null && resolution.getResolvedHolder().isProgramClass()) {
                  return TraversalContinuation.BREAK;
                }
              }
              return TraversalContinuation.CONTINUE;
            },
            lambda -> {
              // Lambda classes do not have finalizers.
              return TraversalContinuation.CONTINUE;
            },
            this)
        .shouldBreak();
  }

  /** Predicate on types that *must* never be merged horizontally. */
  public boolean isNoHorizontalClassMergingOfType(DexType type) {
    return noClassMerging.contains(type) || noHorizontalClassMerging.contains(type);
  }

  /** Predicate on types that *must* never be merged vertically. */
  public boolean isNoVerticalClassMergingOfType(DexType type) {
    return noClassMerging.contains(type) || noVerticalClassMerging.contains(type);
  }

  /**
   * All types that *must* never be merged by the static class merger due to a configuration
   * directive (testing only).
   */
  public Set<DexType> getNoStaticClassMergingSet() {
    return noStaticClassMerging;
  }
}