// 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.cf.code;

import com.android.tools.r8.cf.CfPrinter;
import com.android.tools.r8.dex.Constants;
import com.android.tools.r8.errors.Unreachable;
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.DexProgramClass;
import com.android.tools.r8.graph.DexProto;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.graph.GraphLense;
import com.android.tools.r8.graph.UseRegistry;
import com.android.tools.r8.ir.code.Invoke;
import com.android.tools.r8.ir.code.Invoke.Type;
import com.android.tools.r8.ir.code.ValueType;
import com.android.tools.r8.ir.conversion.CfSourceCode;
import com.android.tools.r8.ir.conversion.CfState;
import com.android.tools.r8.ir.conversion.CfState.Slot;
import com.android.tools.r8.ir.conversion.IRBuilder;
import com.android.tools.r8.ir.optimize.Inliner.ConstraintWithTarget;
import com.android.tools.r8.ir.optimize.InliningConstraints;
import com.android.tools.r8.jar.InliningConstraintVisitor;
import com.android.tools.r8.naming.NamingLens;
import java.util.Arrays;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

public class CfInvoke extends CfInstruction {

  private final DexMethod method;
  private final int opcode;
  private final boolean itf;

  public CfInvoke(int opcode, DexMethod method, boolean itf) {
    assert Opcodes.INVOKEVIRTUAL <= opcode && opcode <= Opcodes.INVOKEINTERFACE;
    assert !(opcode == Opcodes.INVOKEVIRTUAL && itf) : "InvokeVirtual on interface type";
    assert !(opcode == Opcodes.INVOKEINTERFACE && !itf) : "InvokeInterface on class type";
    this.opcode = opcode;
    this.method = method;
    this.itf = itf;
  }

  public DexMethod getMethod() {
    return method;
  }

  public int getOpcode() {
    return opcode;
  }

  public boolean isInterface() {
    return itf;
  }

  @Override
  public CfInvoke asInvoke() {
    return this;
  }

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

  @Override
  public void write(MethodVisitor visitor, NamingLens lens) {
    String owner = lens.lookupInternalName(method.holder);
    String name = lens.lookupName(method).toString();
    String desc = method.proto.toDescriptorString(lens);
    visitor.visitMethodInsn(opcode, owner, name, desc, itf);
  }

  @Override
  public void print(CfPrinter printer) {
    printer.print(this);
  }

  @Override
  public void registerUse(UseRegistry registry, DexType clazz) {
    switch (opcode) {
      case Opcodes.INVOKEINTERFACE:
        registry.registerInvokeInterface(method);
        break;
      case Opcodes.INVOKEVIRTUAL:
        registry.registerInvokeVirtual(method);
        break;
      case Opcodes.INVOKESPECIAL:
        if (method.name.toString().equals(Constants.INSTANCE_INITIALIZER_NAME)) {
          registry.registerInvokeDirect(method);
        } else if (method.holder == clazz) {
          registry.registerInvokeDirect(method);
        } else {
          registry.registerInvokeSuper(method);
        }
        break;
      case Opcodes.INVOKESTATIC:
        registry.registerInvokeStatic(method);
        break;
      default:
        throw new Unreachable("unknown CfInvoke opcode " + opcode);
    }
  }

  public boolean isInvokeSuper(DexType clazz) {
    return opcode == Opcodes.INVOKESPECIAL &&
        method.holder != clazz &&
        !method.name.toString().equals(Constants.INSTANCE_INITIALIZER_NAME);
  }

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

  @Override
  public void buildIR(IRBuilder builder, CfState state, CfSourceCode code) {
    Invoke.Type type;
    DexMethod canonicalMethod;
    DexProto callSiteProto = null;
    switch (opcode) {
      case Opcodes.INVOKEINTERFACE:
        {
          canonicalMethod = method;
          type = Type.INTERFACE;
          break;
        }
      case Opcodes.INVOKEVIRTUAL:
        {
          canonicalMethod =
              builder.appView.dexItemFactory().polymorphicMethods.canonicalize(method);
          if (canonicalMethod == null) {
            type = Type.VIRTUAL;
            canonicalMethod = method;
          } else {
            type = Type.POLYMORPHIC;
            callSiteProto = method.proto;
          }
          break;
        }
      case Opcodes.INVOKESPECIAL:
        {
          // Per https://source.android.com/devices/tech/dalvik/dalvik-bytecode, for Dex files
          // version >= 037, if the method refers to an interface method, invoke-super is used to
          // invoke the most specific, non-overridden version of that method.
          // In https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.12.3, it is
          // a compile-time error in the case that "If TypeName denotes an interface, let T be the
          // type declaration immediately enclosing the method invocation. A compile-time error
          // occurs if there exists a method, distinct from the compile-time declaration, that
          // overrides (§9.4.1) the compile-time declaration from a direct superclass or
          // direct superinterface of T."
          // Using invoke-super should therefore observe the correct semantics since we cannot
          // target less specific targets (up in the hierarchy).
          canonicalMethod = method;
          if (method.name.toString().equals(Constants.INSTANCE_INITIALIZER_NAME)) {
            type = Type.DIRECT;
          } else if (code.getOriginalHolder() == method.holder) {
            if (!this.itf || builder.appView.options().isInterfaceMethodDesugaringEnabled()) {
              // When desugaring default interface methods, it is expected they are targeted with
              // invoke-direct.
              type = Type.DIRECT;
            } else {
              DexProgramClass clazz = builder.appView.definitionForProgramType(method.holder);
              assert clazz != null;
              DexEncodedMethod encodedMethod = clazz.lookupDirectMethod(method);
              if (encodedMethod != null) {
                assert encodedMethod.isStatic() || encodedMethod.isPrivateMethod();
                type = Type.DIRECT;
              } else {
                // This is a default interface method.
                type = Type.SUPER;
              }
            }
          } else {
            type = Type.SUPER;
          }
          assert type == Type.SUPER || type == Type.DIRECT;
          break;
        }
      case Opcodes.INVOKESTATIC:
        {
          canonicalMethod = method;
          type = Type.STATIC;
          break;
        }
      default:
        throw new Unreachable("unknown CfInvoke opcode " + opcode);
    }
    int parameterCount = method.proto.parameters.size();
    if (type != Type.STATIC) {
      parameterCount += 1;
    }
    ValueType[] types = new ValueType[parameterCount];
    Integer[] registers = new Integer[parameterCount];
    for (int i = parameterCount - 1; i >= 0; i--) {
      Slot slot = state.pop();
      types[i] = slot.type;
      registers[i] = slot.register;
    }
    builder.addInvoke(
        type, canonicalMethod, callSiteProto, Arrays.asList(types), Arrays.asList(registers), itf);
    if (!method.proto.returnType.isVoidType()) {
      builder.addMoveResult(state.push(method.proto.returnType).register);
    }
  }

  @Override
  public ConstraintWithTarget inliningConstraint(
      InliningConstraints inliningConstraints,
      DexType invocationContext,
      GraphLense graphLense,
      AppView<?> appView) {
    return InliningConstraintVisitor.getConstraintForInvoke(
        opcode, method, graphLense, appView, inliningConstraints, invocationContext);
  }
}