src/main/java/com/android/tools/r8/shaking/EnqueuerEnumReflectionAnalysisBase.java

// Copyright (c) 2025, 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 com.android.tools.r8.graph.AppInfoWithClassHierarchy;
import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.DexClass;
import com.android.tools.r8.graph.DexProgramClass;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.graph.ProgramMethod;
import com.android.tools.r8.graph.analysis.EnqueuerAnalysisCollection;
import com.android.tools.r8.graph.analysis.IrBasedEnqueuerAnalysis;
import com.android.tools.r8.graph.analysis.TraceInvokeEnqueuerAnalysis;
import com.android.tools.r8.ir.analysis.type.ClassTypeElement;
import com.android.tools.r8.ir.analysis.type.TypeElement;
import com.android.tools.r8.ir.code.ConstClass;
import com.android.tools.r8.ir.code.InvokeMethod;
import com.android.tools.r8.ir.code.Value;

abstract class EnqueuerEnumReflectionAnalysisBase
    implements TraceInvokeEnqueuerAnalysis, IrBasedEnqueuerAnalysis {
  private final AppView<? extends AppInfoWithClassHierarchy> appView;
  protected final Enqueuer enqueuer;

  public EnqueuerEnumReflectionAnalysisBase(
      AppView<? extends AppInfoWithClassHierarchy> appView, Enqueuer enqueuer) {
    this.appView = appView;
    this.enqueuer = enqueuer;
  }

  public void register(EnqueuerAnalysisCollection.Builder builder) {
    builder.addTraceInvokeAnalysis(this);
    builder.addIrBasedEnqueuerAnalysis(this);
  }

  protected DexProgramClass maybeGetProgramEnumType(DexType type, boolean checkSuper) {
    // Arrays can be used for serialization-related methods.
    if (type.isArrayType()) {
      type = type.getBaseType();
      if (!type.isClassType()) {
        return null;
      }
    }

    DexClass dexClass = appView.definitionFor(type);
    if (dexClass == null || !dexClass.isProgramClass() || !dexClass.hasSuperType()) {
      return null;
    }
    DexType superType = dexClass.getSuperType();
    if (superType.isIdenticalTo(appView.dexItemFactory().enumType)) {
      return dexClass.asProgramClass();
    }
    // Cannot have a sub-sub-type of an Enum.
    return checkSuper ? maybeGetProgramEnumType(superType, false) : null;
  }

  protected void handleReflectiveEnumInvoke(
      ProgramMethod context, InvokeMethod invoke, int classParamIndex) {
    // The use of java.lang.Enum.valueOf(java.lang.Class, java.lang.String) will indirectly
    // access the values() method of the enum class passed as the first argument. The method
    // SomeEnumClass.valueOf(java.lang.String) which is generated by javac for all enums will
    // call this method.
    // Likewise, EnumSet and EnumMap call values() on the passed in Class.
    Value arg = invoke.getArgumentForParameter(classParamIndex);
    DexType type;
    if (invoke
        .getInvokedMethod()
        .getParameter(classParamIndex)
        .isIdenticalTo(appView.dexItemFactory().classType)) {
      // EnumMap.<init>(), EnumSet.noneOf(), EnumSet.allOf(), Enum.valueOf(),
      // Bundle.getSerializable(), Parcel.readSerializable(), Intent.getSerializableExtra().
      // A phi has no single definition, so it cannot be matched to a const-class.
      if (arg.isPhi()) {
        return;
      }
      ConstClass constClass = arg.definition.asConstClass();
      if (constClass == null) {
        return;
      }
      type = constClass.getType();
    } else {
      // EnumSet.of(), EnumSet.range(), Intent.putExtra().
      // Phis are allowed here since their type is the join of their operands' types, so a phi of
      // values of the same enum type (e.g. "cond ? MyEnum.A : MyEnum.B") still has that type.
      TypeElement typeElement = arg.getType();
      if (typeElement.isArrayType()) {
        typeElement = typeElement.asArrayType().getBaseType();
      }
      ClassTypeElement classTypeElement = typeElement.asClassType();
      if (classTypeElement == null) {
        return;
      }
      type = classTypeElement.getClassType();
    }
    DexProgramClass clazz = maybeGetProgramEnumType(type, true);
    if (clazz != null) {
      enqueuer.markEnumValuesAsReachable(clazz, KeepReason.invokedFrom(context));
    }
  }
}