// Copyright (c) 2017, 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.ir.code;

import com.android.tools.r8.cf.LoadStoreHelper;
import com.android.tools.r8.cf.TypeVerificationHelper;
import com.android.tools.r8.errors.Unreachable;
import com.android.tools.r8.graph.AppInfoWithSubtyping;
import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.DexEncodedMethod;
import com.android.tools.r8.graph.DexMethod;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.graph.LookupResult.LookupResultSuccess;
import com.android.tools.r8.graph.ResolutionResult;
import com.android.tools.r8.ir.analysis.ClassInitializationAnalysis;
import com.android.tools.r8.ir.analysis.fieldvalueanalysis.AbstractFieldSet;
import com.android.tools.r8.ir.analysis.modeling.LibraryMethodReadSetModeling;
import com.android.tools.r8.ir.analysis.type.TypeAnalysis;
import com.android.tools.r8.ir.analysis.value.AbstractValue;
import com.android.tools.r8.ir.analysis.value.UnknownValue;
import com.android.tools.r8.ir.optimize.DefaultInliningOracle;
import com.android.tools.r8.ir.optimize.Inliner.InlineAction;
import com.android.tools.r8.ir.optimize.Inliner.Reason;
import com.android.tools.r8.ir.optimize.inliner.WhyAreYouNotInliningReporter;
import com.android.tools.r8.ir.regalloc.RegisterAllocator;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Sets;
import java.util.BitSet;
import java.util.Collection;
import java.util.List;
import java.util.Set;

public abstract class InvokeMethod extends Invoke {

  private final DexMethod method;

  public InvokeMethod(DexMethod target, Value result, List<Value> arguments) {
    super(result, arguments);
    this.method = target;
  }

  @Override
  public DexType getReturnType() {
    return method.proto.returnType;
  }

  public DexMethod getInvokedMethod() {
    return method;
  }

  @Override
  public boolean identicalNonValueNonPositionParts(Instruction other) {
    return other.isInvokeMethod() && method == other.asInvokeMethod().getInvokedMethod();
  }

  @Override
  public String toString() {
    return super.toString() + "; method: " + method.toSourceString();
  }

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

  @Override
  public InvokeMethod asInvokeMethod() {
    return this;
  }

  // In subclasses, e.g., invoke-virtual or invoke-super, use a narrower receiver type by using
  // receiver type and calling context---the holder of the method where the current invocation is.
  // TODO(b/140204899): Refactor lookup methods to be defined in a single place.
  public abstract DexEncodedMethod lookupSingleTarget(
      AppView<?> appView, DexType invocationContext);

  // TODO(b/140204899): Refactor lookup methods to be defined in a single place.
  public Collection<DexEncodedMethod> lookupTargets(
      AppView<? extends AppInfoWithSubtyping> appView, DexType invocationContext) {
    // Leverage exact receiver type if available.
    DexEncodedMethod singleTarget = lookupSingleTarget(appView, invocationContext);
    if (singleTarget != null) {
      return ImmutableList.of(singleTarget);
    }
    if (!isInvokeMethodWithDynamicDispatch() || !appView.appInfo().hasLiveness()) {
      return null;
    }
    LookupResultSuccess lookupResult =
        appView
            .appInfo()
            .resolveMethod(method.holder, method)
            .lookupVirtualDispatchTargets(
                appView.definitionForProgramType(invocationContext),
                appView.withLiveness().appInfo())
            .asLookupResultSuccess();
    if (lookupResult == null || lookupResult.isEmpty()) {
      return null;
    }
    assert lookupResult.hasMethodTargets();
    if (lookupResult.hasLambdaTargets()) {
      // TODO(b/150277553): Support lambda targets.
      return null;
    }
    DexType staticReceiverType = getInvokedMethod().holder;
    DexType refinedReceiverType =
        TypeAnalysis.getRefinedReceiverType(
            appView.withLiveness(), this.asInvokeMethodWithReceiver());
    // TODO(b/140204899): Instead of reprocessing here, pass refined receiver to lookup.
    // Leverage refined receiver type if available.
    if (refinedReceiverType != staticReceiverType) {
      ResolutionResult refinedResolution =
          appView.appInfo().resolveMethod(refinedReceiverType, method);
      if (refinedResolution.isSingleResolution()) {
        DexEncodedMethod refinedTarget = refinedResolution.getSingleTarget();
        Set<DexEncodedMethod> result = Sets.newIdentityHashSet();
        lookupResult.forEach(
            methodTarget -> {
              DexEncodedMethod target = methodTarget.getMethod();
              if (target == refinedTarget
                  || appView.isSubtype(target.holder(), refinedReceiverType).isPossiblyTrue()) {
                result.add(target);
              }
            },
            lambdaTarget -> {
              throw new Unreachable();
            });
        return result;
      }
      // If resolution at the refined type fails, conservatively return the full set of targets.
    }
    Set<DexEncodedMethod> result = Sets.newIdentityHashSet();
    lookupResult.forEach(
        methodTarget -> result.add(methodTarget.getMethod()),
        lambda -> {
          assert false;
        });
    return result;
  }

  public abstract InlineAction computeInlining(
      DexEncodedMethod singleTarget,
      Reason reason,
      DefaultInliningOracle decider,
      ClassInitializationAnalysis classInitializationAnalysis,
      WhyAreYouNotInliningReporter whyAreYouNotInliningReporter);

  @Override
  public boolean identicalAfterRegisterAllocation(Instruction other, RegisterAllocator allocator) {
    if (!super.identicalAfterRegisterAllocation(other, allocator)) {
      return false;
    }

    if (allocator.options().canHaveIncorrectJoinForArrayOfInterfacesBug()) {
      InvokeMethod invoke = other.asInvokeMethod();

      // If one of the arguments of this invoke is an array, then make sure that the corresponding
      // argument of the other invoke is the exact same value. Otherwise, the verifier may
      // incorrectly join the types of these arrays to Object[].
      for (int i = 0; i < arguments().size(); ++i) {
        Value argument = arguments().get(i);
        if (argument.getType().isArrayType() && argument != invoke.arguments().get(i)) {
          return false;
        }
      }
    }

    return true;
  }

  @Override
  public void insertLoadAndStores(InstructionListIterator it, LoadStoreHelper helper) {
    helper.loadInValues(this, it);
    if (getReturnType().isVoidType()) {
      return;
    }
    if (outValue == null) {
      helper.popOutType(getReturnType(), this, it);
    } else {
      assert outValue.isUsed();
      helper.storeOutValue(this, it);
    }
  }

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

  @Override
  public DexType computeVerificationType(AppView<?> appView, TypeVerificationHelper helper) {
    return getReturnType();
  }

  @Override
  public boolean instructionMayTriggerMethodInvocation(AppView<?> appView, DexType context) {
    return true;
  }

  @Override
  public AbstractFieldSet readSet(AppView<?> appView, DexType context) {
    return LibraryMethodReadSetModeling.getModeledReadSetOrUnknown(this, appView.dexItemFactory());
  }

  @Override
  public AbstractValue getAbstractValue(AppView<?> appView, DexType context) {
    assert hasOutValue();
    DexEncodedMethod method = lookupSingleTarget(appView, context);
    if (method != null) {
      return method.getOptimizationInfo().getAbstractReturnValue();
    }
    return UnknownValue.getInstance();
  }

  boolean verifyD8LookupResult(
      DexEncodedMethod hierarchyResult, DexEncodedMethod lookupDirectTargetOnItself) {
    if (lookupDirectTargetOnItself == null) {
      return true;
    }
    assert lookupDirectTargetOnItself == hierarchyResult;
    return true;
  }

  @Override
  public boolean throwsNpeIfValueIsNull(Value value, AppView<?> appView, DexType context) {
    DexEncodedMethod singleTarget = lookupSingleTarget(appView, context);
    if (singleTarget != null) {
      BitSet nonNullParamOrThrow = singleTarget.getOptimizationInfo().getNonNullParamOrThrow();
      if (nonNullParamOrThrow != null) {
        int argumentIndex = inValues.indexOf(value);
        return argumentIndex >= 0 && nonNullParamOrThrow.get(argumentIndex);
      }
    }
    return false;
  }
}