org.jetbrains.kotlin.codegen.optimization.RedundantCheckCastElimination.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2017 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jetbrains.kotlin.codegen.optimization
import org.jetbrains.kotlin.codegen.inline.ReifiedTypeInliner
import org.jetbrains.kotlin.codegen.optimization.common.OptimizationBasicInterpreter
import org.jetbrains.kotlin.codegen.optimization.fixStack.top
import org.jetbrains.kotlin.codegen.optimization.transformer.MethodTransformer
import org.jetbrains.org.objectweb.asm.Opcodes
import org.jetbrains.org.objectweb.asm.Type
import org.jetbrains.org.objectweb.asm.tree.*
class RedundantCheckCastEliminationMethodTransformer : MethodTransformer() {
override fun transform(internalClassName: String, methodNode: MethodNode) {
val insns = methodNode.instructions.toArray()
if (!insns.any { it.opcode == Opcodes.CHECKCAST }) return
val redundantCheckCasts = ArrayList()
val frames = analyze(internalClassName, methodNode, OptimizationBasicInterpreter())
for (i in insns.indices) {
val valueType = frames[i]?.top()?.type ?: continue
val insn = insns[i]
if (ReifiedTypeInliner.isOperationReifiedMarker(insn.previous)) continue
if (insn is TypeInsnNode) {
val insnType = Type.getObjectType(insn.desc)
if (!isTrivialSubtype(insnType, valueType)) continue
//Keep casts to multiarray types cause dex doesn't recognize ANEWARRAY [Ljava/lang/Object; as Object [][], but Object [] type
//It's not clear is it bug in dex or not and maybe best to distinguish such types from MULTINEWARRRAY ones in method analyzer
if (isMultiArrayType(insnType)) continue
if (insn.opcode == Opcodes.CHECKCAST) {
redundantCheckCasts.add(insn)
}
}
}
redundantCheckCasts.forEach {
methodNode.instructions.remove(it)
}
}
private fun isTrivialSubtype(superType: Type, subType: Type) =
superType == subType
private fun isMultiArrayType(type: Type) = type.sort == Type.ARRAY && type.dimensions != 1
}