// Copyright (c) 2016, 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.graph;

import static com.android.tools.r8.graph.DexEncodedMethod.CompilationState.PROCESSED_INLINING_CANDIDATE_ANY;
import static com.android.tools.r8.graph.DexEncodedMethod.CompilationState.PROCESSED_INLINING_CANDIDATE_SAME_CLASS;
import static com.android.tools.r8.graph.DexEncodedMethod.CompilationState.PROCESSED_INLINING_CANDIDATE_SAME_PACKAGE;
import static com.android.tools.r8.graph.DexEncodedMethod.CompilationState.PROCESSED_INLINING_CANDIDATE_SUBCLASS;
import static com.android.tools.r8.graph.DexEncodedMethod.CompilationState.PROCESSED_NOT_INLINING_CANDIDATE;

import com.android.tools.r8.cf.code.CfConstNull;
import com.android.tools.r8.cf.code.CfInstruction;
import com.android.tools.r8.cf.code.CfThrow;
import com.android.tools.r8.code.Const;
import com.android.tools.r8.code.ConstString;
import com.android.tools.r8.code.ConstStringJumbo;
import com.android.tools.r8.code.Instruction;
import com.android.tools.r8.code.InvokeDirect;
import com.android.tools.r8.code.InvokeStatic;
import com.android.tools.r8.code.NewInstance;
import com.android.tools.r8.code.Throw;
import com.android.tools.r8.dex.Constants;
import com.android.tools.r8.dex.IndexedItemCollection;
import com.android.tools.r8.dex.JumboStringRewriter;
import com.android.tools.r8.dex.MixedSectionCollection;
import com.android.tools.r8.graph.AppInfo.ResolutionResult;
import com.android.tools.r8.graph.DexEncodedMethod.ParameterUsagesInfo.ParameterUsage;
import com.android.tools.r8.ir.code.IRCode;
import com.android.tools.r8.ir.code.Invoke;
import com.android.tools.r8.ir.code.Invoke.Type;
import com.android.tools.r8.ir.code.Position;
import com.android.tools.r8.ir.code.ValueNumberGenerator;
import com.android.tools.r8.ir.code.ValueType;
import com.android.tools.r8.ir.conversion.DexBuilder;
import com.android.tools.r8.ir.optimize.Inliner.Constraint;
import com.android.tools.r8.ir.optimize.Inliner.Reason;
import com.android.tools.r8.ir.regalloc.RegisterAllocator;
import com.android.tools.r8.ir.synthetic.ForwardMethodSourceCode;
import com.android.tools.r8.ir.synthetic.SynthesizedCode;
import com.android.tools.r8.logging.Log;
import com.android.tools.r8.naming.ClassNameMapper;
import com.android.tools.r8.naming.MemberNaming.MethodSignature;
import com.android.tools.r8.naming.MemberNaming.Signature;
import com.android.tools.r8.naming.NamingLens;
import com.android.tools.r8.origin.Origin;
import com.android.tools.r8.utils.InternalOptions;
import com.google.common.collect.ImmutableList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.function.Consumer;
import java.util.stream.Collectors;

public class DexEncodedMethod extends KeyedDexItem<DexMethod> implements ResolutionResult {

  /**
   * Encodes the processing state of a method.
   * <p>
   * We also use this enum to encode under what constraints a method may be inlined.
   */
  public enum CompilationState {
    /**
     * Has not been processed, yet.
     */
    NOT_PROCESSED,
    /**
     * Has been processed but cannot be inlined due to instructions that are not supported.
     */
    PROCESSED_NOT_INLINING_CANDIDATE,
    /**
     * Code only contains instructions that access public entities and can this be inlined into any
     * context.
     */
    PROCESSED_INLINING_CANDIDATE_ANY,
    /**
     * Code also contains instructions that access protected entities that reside in a differnt
     * package and hence require subclass relationship to be visible.
     */
    PROCESSED_INLINING_CANDIDATE_SUBCLASS,
    /**
     * Code contains instructions that reference package private entities or protected entities from
     * the same package.
     */
    PROCESSED_INLINING_CANDIDATE_SAME_PACKAGE,
    /**
     * Code contains instructions that reference private entities.
     */
    PROCESSED_INLINING_CANDIDATE_SAME_CLASS,
  }

  public static final DexEncodedMethod[] EMPTY_ARRAY = new DexEncodedMethod[]{};
  public static final DexEncodedMethod SENTINEL =
      new DexEncodedMethod(null, null, null, null, null);

  public final DexMethod method;
  public final MethodAccessFlags accessFlags;
  public DexAnnotationSet annotations;
  public ParameterAnnotationsList parameterAnnotationsList;
  private Code code;
  private CompilationState compilationState = CompilationState.NOT_PROCESSED;
  private OptimizationInfo optimizationInfo = DefaultOptimizationInfo.DEFAULT;
  private int classFileVersion = -1;

  public DexEncodedMethod(
      DexMethod method,
      MethodAccessFlags accessFlags,
      DexAnnotationSet annotations,
      ParameterAnnotationsList parameterAnnotationsList,
      Code code) {
    this.method = method;
    this.accessFlags = accessFlags;
    this.annotations = annotations;
    this.parameterAnnotationsList = parameterAnnotationsList;
    this.code = code;
    assert code == null || !accessFlags.isAbstract();
  }

  public DexEncodedMethod(
      DexMethod method,
      MethodAccessFlags flags,
      DexAnnotationSet annotationSet,
      ParameterAnnotationsList annotationsList,
      Code code,
      int classFileVersion) {
    this(method, flags, annotationSet, annotationsList, code);
    this.classFileVersion = classFileVersion;
  }

  public boolean isProcessed() {
    return compilationState != CompilationState.NOT_PROCESSED;
  }

  public boolean isInstanceInitializer() {
    return accessFlags.isConstructor() && !accessFlags.isStatic();
  }

  public boolean isDefaultInitializer() {
    return isInstanceInitializer() && method.proto.parameters.isEmpty();
  }

  public boolean isClassInitializer() {
    return accessFlags.isConstructor() && accessFlags.isStatic();
  }

  /**
   * Returns true if this method can be invoked via invoke-virtual, invoke-super or
   * invoke-interface.
   */
  public boolean isVirtualMethod() {
    return !accessFlags.isStatic() && !accessFlags.isPrivate() && !accessFlags.isConstructor();
  }

  /**
   * Returns true if this method can be invoked via invoke-virtual, invoke-super or invoke-interface
   * and is non-abstract.
   */
  public boolean isNonAbstractVirtualMethod() {
    return isVirtualMethod() && !accessFlags.isAbstract();
  }

  public boolean isPublicMethod() {
    return accessFlags.isPublic();
  }

  public boolean isPrivateMethod() {
    return accessFlags.isPrivate();
  }

  /**
   * Returns true if this method can be invoked via invoke-direct.
   */
  public boolean isDirectMethod() {
    return (accessFlags.isPrivate() || accessFlags.isConstructor()) && !accessFlags.isStatic();
  }

  /**
   * Returns true if this method can be invoked via invoke-static.
   */
  public boolean isStaticMethod() {
    return accessFlags.isStatic();
  }


  /**
   * Returns true if this method is synthetic.
   */
  public boolean isSyntheticMethod() {
    return accessFlags.isSynthetic();
  }


  public boolean isInliningCandidate(DexEncodedMethod container, Reason inliningReason,
      AppInfoWithSubtyping appInfo) {
    return isInliningCandidate(container.method.getHolder(), inliningReason, appInfo);
  }

  public boolean isInliningCandidate(DexType containerType, Reason inliningReason,
      AppInfoWithSubtyping appInfo) {
    if (isClassInitializer()) {
      // This will probably never happen but never inline a class initializer.
      return false;
    }
    if (inliningReason == Reason.FORCE) {
      // Make sure we would be able to inline this normally.
      assert isInliningCandidate(containerType, Reason.SIMPLE, appInfo);
      return true;
    }
    switch (compilationState) {
      case PROCESSED_INLINING_CANDIDATE_ANY:
        return true;
      case PROCESSED_INLINING_CANDIDATE_SUBCLASS:
        return containerType.isSubtypeOf(method.getHolder(), appInfo);
      case PROCESSED_INLINING_CANDIDATE_SAME_PACKAGE:
        return containerType.isSamePackage(method.getHolder());
      case PROCESSED_INLINING_CANDIDATE_SAME_CLASS:
        return containerType == method.getHolder();
      default:
        return false;
    }
  }

  public boolean markProcessed(Constraint state) {
    CompilationState prevCompilationState = compilationState;
    switch (state) {
      case ALWAYS:
        compilationState = PROCESSED_INLINING_CANDIDATE_ANY;
        break;
      case SUBCLASS:
        compilationState = PROCESSED_INLINING_CANDIDATE_SUBCLASS;
        break;
      case PACKAGE:
        compilationState = PROCESSED_INLINING_CANDIDATE_SAME_PACKAGE;
        break;
      case SAMECLASS:
        compilationState = PROCESSED_INLINING_CANDIDATE_SAME_CLASS;
        break;
      case NEVER:
        compilationState = PROCESSED_NOT_INLINING_CANDIDATE;
        break;
    }
    return prevCompilationState != compilationState;
  }

  public void markNotProcessed() {
    compilationState = CompilationState.NOT_PROCESSED;
  }

  public IRCode buildIR(AppInfo appInfo, InternalOptions options, Origin origin) {
    return code == null ? null : code.buildIR(this, appInfo, options, origin);
  }

  public IRCode buildInliningIRForTesting(
      InternalOptions options, ValueNumberGenerator valueNumberGenerator) {
    return buildInliningIR(null, options, valueNumberGenerator, null, Origin.unknown());
  }

  public IRCode buildInliningIR(
      AppInfo appInfo,
      InternalOptions options,
      ValueNumberGenerator valueNumberGenerator,
      Position callerPosition,
      Origin origin) {
    return code.buildInliningIR(
        this, appInfo, options, valueNumberGenerator, callerPosition, origin);
  }

  public void setCode(Code code) {
    this.code = code;
  }

  public void setCode(
      IRCode ir,
      RegisterAllocator registerAllocator,
      InternalOptions options) {
    final DexBuilder builder = new DexBuilder(ir, registerAllocator, options);
    code = builder.build(method.getArity());
  }

  @Override
  public String toString() {
    return "Encoded method " + method;
  }

  @Override
  public void collectIndexedItems(IndexedItemCollection indexedItems,
      DexMethod method, int instructionOffset) {
    this.method.collectIndexedItems(indexedItems);
    if (code != null) {
      code.collectIndexedItems(indexedItems, this.method);
    }
    annotations.collectIndexedItems(indexedItems);
    parameterAnnotationsList.collectIndexedItems(indexedItems);
  }

  @Override
  void collectMixedSectionItems(MixedSectionCollection mixedItems) {
    if (code != null) {
      code.collectMixedSectionItems(mixedItems);
    }
    annotations.collectMixedSectionItems(mixedItems);
    parameterAnnotationsList.collectMixedSectionItems(mixedItems);
  }

  public Code getCode() {
    return code;
  }

  public void setDexCode(DexCode code) {
    this.code = code;
  }

  public void removeCode() {
    code = null;
  }

  public boolean hasDebugPositions() {
    assert code != null && code.isDexCode();
    return code.asDexCode().hasDebugPositions();
  }

  public int getClassFileVersion() {
    assert classFileVersion >= 0;
    return classFileVersion;
  }

  public boolean hasClassFileVersion() {
    return classFileVersion >= 0;
  }

  public void upgradeClassFileVersion(int version) {
    assert version >= 0;
    assert !hasClassFileVersion() || version >= getClassFileVersion();
    classFileVersion = version;
  }

  public String qualifiedName() {
    return method.qualifiedName();
  }

  public String descriptor() {
    return descriptor(NamingLens.getIdentityLens());
  }

  public String descriptor(NamingLens namingLens) {
    StringBuilder builder = new StringBuilder();
    builder.append("(");
    for (DexType type : method.proto.parameters.values) {
      builder.append(namingLens.lookupDescriptor(type).toString());
    }
    builder.append(")");
    builder.append(namingLens.lookupDescriptor(method.proto.returnType).toString());
    return builder.toString();
  }

  public String toSmaliString(ClassNameMapper naming) {
    StringBuilder builder = new StringBuilder();
    builder.append(".method ");
    builder.append(accessFlags.toSmaliString());
    builder.append(" ");
    builder.append(method.name.toSmaliString());
    builder.append(method.proto.toSmaliString());
    builder.append("\n");
    if (code != null) {
      DexCode dexCode = code.asDexCode();
      builder.append("    .registers ");
      builder.append(dexCode.registerSize);
      builder.append("\n\n");
      builder.append(dexCode.toSmaliString(naming));
    }
    builder.append(".end method\n");
    return builder.toString();
  }

  @Override
  public String toSourceString() {
    return method.toSourceString();
  }

  public DexEncodedMethod toAbstractMethod() {
    accessFlags.setAbstract();
    this.code = null;
    return this;
  }

  /**
   * Generates a {@link DexCode} object for the given instructions.
   * <p>
   * As the code object is produced outside of the normal compilation cycle, it has to use {@link
   * ConstStringJumbo} to reference string constants. Hence, code produced form these templates
   * might incur a size overhead.
   */
  private DexCode generateCodeFromTemplate(
      int numberOfRegisters, int outRegisters, Instruction... instructions) {
    int offset = 0;
    for (Instruction instruction : instructions) {
      assert !(instruction instanceof ConstString);
      instruction.setOffset(offset);
      offset += instruction.getSize();
    }
    int requiredArgRegisters = accessFlags.isStatic() ? 0 : 1;
    for (DexType type : method.proto.parameters.values) {
      requiredArgRegisters += ValueType.fromDexType(type).requiredRegisters();
    }
    // Passing null as highestSortingString is save, as ConstString instructions are not allowed.
    return new DexCode(Math.max(numberOfRegisters, requiredArgRegisters), requiredArgRegisters,
        outRegisters, instructions, new DexCode.Try[0], new DexCode.TryHandler[0], null, null);
  }

  public DexEncodedMethod toEmptyThrowingMethodDex() {
    assert !accessFlags.isAbstract() && !accessFlags.isNative();
    Builder builder = builder(this);
    Instruction insn[] = {new Const(0, 0), new Throw(0)};
    DexCode emptyThrowingCode = generateCodeFromTemplate(1, 0, insn);
    builder.setCode(emptyThrowingCode);
    return builder.build();
  }

  public DexEncodedMethod toEmptyThrowingMethodCf() {
    assert !accessFlags.isAbstract() && !accessFlags.isNative();
    Builder builder = builder(this);
    CfInstruction insn[] = {new CfConstNull(), new CfThrow()};
    CfCode emptyThrowingCode =
        new CfCode(
            method,
            1,
            method.proto.parameters.size() + 1,
            Arrays.asList(insn),
            Collections.emptyList(),
            Collections.emptyList());
    builder.setCode(emptyThrowingCode);
    return builder.build();
  }

  public DexEncodedMethod toMethodThatLogsError(DexItemFactory itemFactory) {
    Signature signature = MethodSignature.fromDexMethod(method);
    // TODO(herhut): Construct this out of parts to enable reuse, maybe even using descriptors.
    DexString message = itemFactory.createString(
        "Shaking error: Missing method in " + method.holder.toSourceString() + ": "
            + signature);
    DexString tag = itemFactory.createString("TOIGHTNESS");
    DexType[] args = {itemFactory.stringType, itemFactory.stringType};
    DexProto proto = itemFactory.createProto(itemFactory.intType, args);
    DexMethod logMethod = itemFactory
        .createMethod(itemFactory.createType("Landroid/util/Log;"), proto,
            itemFactory.createString("e"));
    DexType exceptionType = itemFactory.createType("Ljava/lang/RuntimeException;");
    DexMethod exceptionInitMethod = itemFactory
        .createMethod(exceptionType, itemFactory.createProto(itemFactory.voidType,
            itemFactory.stringType),
            itemFactory.constructorMethodName);
    DexCode code;
    if (isInstanceInitializer()) {
      // The Java VM Spec requires that a constructor calls an initializer from the super class
      // or another constructor from the current class. For simplicity we do the latter by just
      // calling ourself. This is ok, as the constructor always throws before the recursive call.
      code = generateCodeFromTemplate(3, 2, new ConstStringJumbo(0, tag),
          new ConstStringJumbo(1, message),
          new InvokeStatic(2, logMethod, 0, 1, 0, 0, 0),
          new NewInstance(0, exceptionType),
          new InvokeDirect(2, exceptionInitMethod, 0, 1, 0, 0, 0),
          new Throw(0),
          new InvokeDirect(1, method, 2, 0, 0, 0, 0));

    } else {
      // These methods might not get registered for jumbo string processing, therefore we always
      // use the jumbo string encoding for the const string instruction.
      code = generateCodeFromTemplate(2, 2, new ConstStringJumbo(0, tag),
          new ConstStringJumbo(1, message),
          new InvokeStatic(2, logMethod, 0, 1, 0, 0, 0),
          new NewInstance(0, exceptionType),
          new InvokeDirect(2, exceptionInitMethod, 0, 1, 0, 0, 0),
          new Throw(0));
    }
    Builder builder = builder(this);
    builder.setCode(code);
    return builder.build();
  }

  public DexEncodedMethod toTypeSubstitutedMethod(DexMethod method) {
    if (this.method == method) {
      return this;
    }
    Builder builder = builder(this);
    builder.setMethod(method);
    return builder.build();
  }

  public DexEncodedMethod toRenamedMethod(DexString name, DexItemFactory factory) {
    if (method.name == name) {
      return this;
    }
    DexMethod newMethod = factory.createMethod(method.holder, method.proto, name);
    Builder builder = builder(this);
    builder.setMethod(newMethod);
    return builder.build();
  }

  public DexEncodedMethod toForwardingMethod(DexClass holder, DexItemFactory itemFactory) {
    assert accessFlags.isPublic();
    // Clear the final flag, as this method is now overwritten. Do this before creating the builder
    // for the forwarding method, as the forwarding method will copy the access flags from this,
    // and if different forwarding methods are created in different subclasses the first could be
    // final.
    accessFlags.unsetFinal();
    DexMethod newMethod = itemFactory.createMethod(holder.type, method.proto, method.name);
    Invoke.Type type = accessFlags.isStatic() ? Invoke.Type.STATIC : Invoke.Type.SUPER;
    Builder builder = builder(this);
    builder.setMethod(newMethod);
    if (accessFlags.isAbstract()) {
      // If the forwarding target is abstract, we can just create an abstract method. While it
      // will not actually forward, it will create the same exception when hit at runtime.
      builder.accessFlags.setAbstract();
    } else {
      // Create code that forwards the call to the target.
      builder.setCode(new SynthesizedCode(
          new ForwardMethodSourceCode(
              accessFlags.isStatic() ? null : holder.type,
              method.proto,
              accessFlags.isStatic() ? null : method.holder,
              method,
              type),
          registry -> {
            if (accessFlags.isStatic()) {
              registry.registerInvokeStatic(method);
            } else {
              registry.registerInvokeSuper(method);
            }
          }));
    }
    builder.accessFlags.setSynthetic();
    return builder.build();
  }

  /**
   * Rewrites the code in this method to have JumboString bytecode if required by mapping.
   * <p>
   * Synchronized such that it can be called concurrently for different mappings. As a side-effect,
   * this will also update the highestSortingString to the index of the strings up to which the code
   * was rewritten to avoid rewriting again unless needed.
   */
  public synchronized void rewriteCodeWithJumboStrings(ObjectToOffsetMapping mapping,
      DexApplication application, boolean force) {
    assert code == null || code.isDexCode();
    if (code == null) {
      return;
    }
    DexCode code = this.code.asDexCode();
    DexString firstJumboString = null;
    if (force) {
      firstJumboString = mapping.getFirstString();
    } else if (code.highestSortingString != null
        && mapping.getOffsetFor(code.highestSortingString) > Constants.MAX_NON_JUMBO_INDEX) {
      firstJumboString = mapping.getFirstJumboString();
    }
    if (firstJumboString != null) {
      JumboStringRewriter rewriter =
          new JumboStringRewriter(this, firstJumboString, application.dexItemFactory);
      rewriter.rewrite();
    }
  }

  public String codeToString() {
    return code == null ? "<no code>" : code.toString(this, null);
  }

  @Override
  public DexMethod getKey() {
    return method;
  }

  public boolean hasAnnotation() {
    return !annotations.isEmpty() || !parameterAnnotationsList.isEmpty();
  }

  public void registerCodeReferences(UseRegistry registry) {
    if (code != null) {
      if (Log.ENABLED) {
        Log.verbose(getClass(), "Registering definitions reachable from `%s`.", method);
      }
      code.registerCodeReferences(registry);
    }
  }

  public static int slowCompare(DexEncodedMethod m1, DexEncodedMethod m2) {
    return m1.method.slowCompareTo(m2.method);
  }

  public static class ClassInlinerEligibility {
    public final boolean returnsReceiver;

    public ClassInlinerEligibility(boolean returnsReceiver) {
      this.returnsReceiver = returnsReceiver;
    }
  }

  public static class TrivialInitializer {
    private TrivialInitializer() {
    }

    // Defines instance trivial initialized, see details in comments
    // to CodeRewriter::computeInstanceInitializerInfo(...)
    public static final class TrivialInstanceInitializer extends TrivialInitializer {
      public static final TrivialInstanceInitializer INSTANCE =
          new TrivialInstanceInitializer();
    }

    // Defines class trivial initialized, see details in comments
    // to CodeRewriter::computeClassInitializerInfo(...)
    public static final class TrivialClassInitializer extends TrivialInitializer {
      public final DexField field;

      public TrivialClassInitializer(DexField field) {
        this.field = field;
      }
    }
  }

  public static final class ParameterUsagesInfo {
    private ImmutableList<ParameterUsage> parametersUsages;

    public ParameterUsagesInfo(List<ParameterUsage> usages) {
      assert !usages.isEmpty();
      parametersUsages = ImmutableList.copyOf(usages);
      assert parametersUsages.size() ==
          parametersUsages.stream().map(usage -> usage.index).collect(Collectors.toSet()).size();
    }

    public static abstract class ParameterUsage {
      public final int index;

      ParameterUsage(int index) {
        this.index = index;
      }
    }

    public static class SingleCallOfArgumentMethod extends ParameterUsage {
      public final Invoke.Type type;
      public final DexMethod method;

      public SingleCallOfArgumentMethod(int index, Type type, DexMethod method) {
        super(index);
        this.type = type;
        this.method = method;
      }
    }

    public static class NotUsed extends ParameterUsage {
      public NotUsed(int index) {
        super(index);
      }
    }

    ParameterUsage getParameterUsage(int parameter) {
      for (ParameterUsage usage : parametersUsages) {
        if (usage.index == parameter) {
          return usage;
        }
      }
      return null;
    }
  }

  public static class OptimizationInfo {

    private int returnedArgument = -1;
    private boolean neverReturnsNull = false;
    private boolean neverReturnsNormally = false;
    private boolean returnsConstant = false;
    private long returnedConstant = 0;
    private boolean forceInline = false;
    private boolean useIdentifierNameString = false;
    private boolean checksNullReceiverBeforeAnySideEffect = false;
    private boolean triggersClassInitBeforeAnySideEffect = false;
    // Stores information about instance methods and constructors for
    // class inliner, null value indicates that the method is not eligible.
    private ClassInlinerEligibility classInlinerEligibility = null;
    private TrivialInitializer trivialInitializerInfo = null;
    private ParameterUsagesInfo parametersUsages = null;

    private OptimizationInfo() {
      // Intentionally left empty.
    }

    private OptimizationInfo(OptimizationInfo template) {
      returnedArgument = template.returnedArgument;
      neverReturnsNull = template.neverReturnsNull;
      returnsConstant = template.returnsConstant;
      returnedConstant = template.returnedConstant;
      forceInline = template.forceInline;
      useIdentifierNameString = template.useIdentifierNameString;
      checksNullReceiverBeforeAnySideEffect = template.checksNullReceiverBeforeAnySideEffect;
    }

    public void setParameterUsages(ParameterUsagesInfo parametersUsages) {
      this.parametersUsages = parametersUsages;
    }

    public ParameterUsage getParameterUsages(int parameter) {
      return parametersUsages == null ? null : parametersUsages.getParameterUsage(parameter);
    }

    public boolean returnsArgument() {
      return returnedArgument != -1;
    }

    public int getReturnedArgument() {
      assert returnsArgument();
      return returnedArgument;
    }

    public boolean neverReturnsNull() {
      return neverReturnsNull;
    }

    public boolean neverReturnsNormally() {
      return neverReturnsNormally;
    }

    public boolean returnsConstant() {
      return returnsConstant;
    }

    private void setClassInlinerEligibility(ClassInlinerEligibility eligibility) {
      this.classInlinerEligibility = eligibility;
    }

    public ClassInlinerEligibility getClassInlinerEligibility() {
      return this.classInlinerEligibility;
    }

    private void setTrivialInitializer(TrivialInitializer info) {
      this.trivialInitializerInfo = info;
    }

    public TrivialInitializer getTrivialInitializerInfo() {
      return this.trivialInitializerInfo;
    }

    public long getReturnedConstant() {
      assert returnsConstant();
      return returnedConstant;
    }

    public boolean forceInline() {
      return forceInline;
    }

    public boolean useIdentifierNameString() {
      return useIdentifierNameString;
    }

    public boolean checksNullReceiverBeforeAnySideEffect() {
      return checksNullReceiverBeforeAnySideEffect;
    }

    public boolean triggersClassInitBeforeAnySideEffect() {
      return triggersClassInitBeforeAnySideEffect;
    }

    private void markReturnsArgument(int argument) {
      assert argument >= 0;
      assert returnedArgument == -1 || returnedArgument == argument;
      returnedArgument = argument;
    }

    private void markNeverReturnsNull() {
      neverReturnsNull = true;
    }

    private void markNeverReturnsNormally() {
      neverReturnsNormally = true;
    }

    private void markReturnsConstant(long value) {
      assert !returnsConstant || returnedConstant == value;
      returnsConstant = true;
      returnedConstant = value;
    }

    private void markForceInline() {
      forceInline = true;
    }

    private void markUseIdentifierNameString() {
      useIdentifierNameString = true;
    }

    public OptimizationInfo copy() {
      return new OptimizationInfo(this);
    }

    private void markCheckNullReceiverBeforeAnySideEffect(boolean mark) {
      checksNullReceiverBeforeAnySideEffect = mark;
    }

    private void markTriggerClassInitBeforeAnySideEffect(boolean mark) {
      triggersClassInitBeforeAnySideEffect = mark;
    }
  }

  private static class DefaultOptimizationInfo extends OptimizationInfo {

    static final OptimizationInfo DEFAULT = new DefaultOptimizationInfo();

    private DefaultOptimizationInfo() {
    }

    @Override
    public OptimizationInfo copy() {
      return this;
    }
  }

  synchronized private OptimizationInfo ensureMutableOI() {
    if (optimizationInfo == DefaultOptimizationInfo.DEFAULT) {
      optimizationInfo = new OptimizationInfo();
    }
    return optimizationInfo;
  }

  synchronized public void markReturnsArgument(int argument) {
    ensureMutableOI().markReturnsArgument(argument);
  }

  synchronized public void markNeverReturnsNull() {
    ensureMutableOI().markNeverReturnsNull();
  }

  synchronized public void markNeverReturnsNormally() {
    ensureMutableOI().markNeverReturnsNormally();
  }

  synchronized public void markReturnsConstant(long value) {
    ensureMutableOI().markReturnsConstant(value);
  }

  synchronized public void setClassInlinerEligibility(ClassInlinerEligibility eligibility) {
    ensureMutableOI().setClassInlinerEligibility(eligibility);
  }

  synchronized public void setParameterUsages(ParameterUsagesInfo parametersUsages) {
    ensureMutableOI().setParameterUsages(parametersUsages);
  }

  synchronized public void setTrivialInitializer(TrivialInitializer info) {
    ensureMutableOI().setTrivialInitializer(info);
  }

  synchronized public void markForceInline() {
    ensureMutableOI().markForceInline();
  }

  synchronized public void markUseIdentifierNameString() {
    ensureMutableOI().markUseIdentifierNameString();
  }

  synchronized public void markCheckNullReceiverBeforeAnySideEffect(boolean mark) {
    ensureMutableOI().markCheckNullReceiverBeforeAnySideEffect(mark);
  }

  synchronized public void markTriggerClassInitBeforeAnySideEffect(boolean mark) {
    ensureMutableOI().markTriggerClassInitBeforeAnySideEffect(mark);
  }

  public OptimizationInfo getOptimizationInfo() {
    return optimizationInfo;
  }

  public void copyMetadataFromInlinee(DexEncodedMethod inlinee) {
    // Record that the current method uses identifier name string if the inlinee did so.
    if (inlinee.getOptimizationInfo().useIdentifierNameString()) {
      markUseIdentifierNameString();
    }
    if (inlinee.classFileVersion > classFileVersion) {
      upgradeClassFileVersion(inlinee.getClassFileVersion());
    }
  }

  private static Builder builder(DexEncodedMethod from) {
    return new Builder(from);
  }

  private static class Builder {

    private DexMethod method;
    private final MethodAccessFlags accessFlags;
    private final DexAnnotationSet annotations;
    private final ParameterAnnotationsList parameterAnnotations;
    private Code code;
    private CompilationState compilationState = CompilationState.NOT_PROCESSED;
    private OptimizationInfo optimizationInfo = DefaultOptimizationInfo.DEFAULT;
    private final int classFileVersion;

    private Builder(DexEncodedMethod from) {
      // Copy all the mutable state of a DexEncodedMethod here.
      method = from.method;
      accessFlags = from.accessFlags.copy();
      annotations = from.annotations;
      parameterAnnotations = from.parameterAnnotationsList;
      code = from.code;
      compilationState = from.compilationState;
      optimizationInfo = from.optimizationInfo.copy();
      classFileVersion = from.classFileVersion;
    }

    public void setMethod(DexMethod method) {
      this.method = method;
    }

    public void setCode(Code code) {
      this.code = code;
    }

    public DexEncodedMethod build() {
      assert method != null;
      assert accessFlags != null;
      assert annotations != null;
      assert parameterAnnotations != null;
      DexEncodedMethod result =
          new DexEncodedMethod(
              method, accessFlags, annotations, parameterAnnotations, code, classFileVersion);
      result.compilationState = compilationState;
      result.optimizationInfo = optimizationInfo;
      return result;
    }
  }

  @Override
  public DexEncodedMethod asResultOfResolve() {
    return this;
  }

  @Override
  public DexEncodedMethod asSingleTarget() {
    return this;
  }

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

  @Override
  public List<DexEncodedMethod> asListOfTargets() {
    return Collections.singletonList(this);
  }

  @Override
  public void forEachTarget(Consumer<DexEncodedMethod> consumer) {
    consumer.accept(this);
  }

}