src/main/java/com/android/tools/r8/optimize/interfaces/analysis/BottomCfFrameState.java

// Copyright (c) 2022, 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.optimize.interfaces.analysis;

import com.android.tools.r8.cf.code.CfAssignability;
import com.android.tools.r8.cf.code.CfFrame;
import com.android.tools.r8.cf.code.CfFrame.FrameType;
import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.DexMethod;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.graph.ProgramMethod;
import com.android.tools.r8.ir.code.ValueType;
import java.util.function.BiFunction;

public class BottomCfFrameState extends CfFrameState {

  private static final BottomCfFrameState INSTANCE = new BottomCfFrameState();

  private BottomCfFrameState() {}

  static BottomCfFrameState getInstance() {
    return INSTANCE;
  }

  @Override
  public boolean isBottom() {
    return true;
  }

  @Override
  public CfFrameState check(AppView<?> appView, CfFrame frame) {
    if (CfAssignability.isFrameAssignable(new CfFrame(), frame, appView).isFailed()) {
      return error();
    }
    CfFrame frameCopy = frame.mutableCopy();
    return new ConcreteCfFrameState(frameCopy.getLocals(), frameCopy.getStack());
  }

  @Override
  public CfFrameState clear() {
    return this;
  }

  @Override
  public CfFrameState markInitialized(FrameType uninitializedType, DexType initializedType) {
    return error();
  }

  @Override
  public CfFrameState pop() {
    return error();
  }

  @Override
  public CfFrameState pop(BiFunction<CfFrameState, FrameType, CfFrameState> fn) {
    return error();
  }

  @Override
  public CfFrameState popAndInitialize(
      AppView<?> appView, DexMethod constructor, ProgramMethod context) {
    return error();
  }

  @Override
  public CfFrameState popInitialized(
      AppView<?> appView,
      DexType expectedType,
      BiFunction<CfFrameState, FrameType, CfFrameState> fn) {
    return error();
  }

  @Override
  public CfFrameState popInitialized(AppView<?> appView, DexType... expectedTypes) {
    return error();
  }

  @Override
  public CfFrameState push(DexType type) {
    return new ConcreteCfFrameState().push(type);
  }

  @Override
  public CfFrameState push(FrameType frameType) {
    return new ConcreteCfFrameState().push(frameType);
  }

  @Override
  public CfFrameState readLocal(
      AppView<?> appView,
      int localIndex,
      ValueType expectedType,
      BiFunction<CfFrameState, FrameType, CfFrameState> fn) {
    return error();
  }

  @Override
  public CfFrameState storeLocal(int localIndex, FrameType frameType) {
    return new ConcreteCfFrameState().storeLocal(localIndex, frameType);
  }

  @Override
  public boolean equals(Object other) {
    return this == other;
  }

  @Override
  public int hashCode() {
    return System.identityHashCode(this);
  }
}