[IR] Add ValueRemapper to avoid reimplementing it each time

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/ValueRemapper.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.backend.common.ir
+
+import org.jetbrains.kotlin.ir.expressions.IrExpression
+import org.jetbrains.kotlin.ir.expressions.IrGetValue
+import org.jetbrains.kotlin.ir.expressions.IrSetValue
+import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
+import org.jetbrains.kotlin.ir.expressions.impl.IrSetValueImpl
+import org.jetbrains.kotlin.ir.symbols.IrValueSymbol
+import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
+
+abstract class AbstractValueRemapper : IrElementTransformerVoid() {
+
+    protected abstract fun remapValue(oldValue: IrValueSymbol): IrValueSymbol?
+
+    override fun visitGetValue(expression: IrGetValue): IrExpression {
+        val newValue = remapValue(expression.symbol) ?: return expression
+        return expression.run { IrGetValueImpl(startOffset, endOffset, newValue, origin) }
+    }
+
+    override fun visitSetValue(expression: IrSetValue): IrExpression {
+        expression.transformChildrenVoid()
+        val newValue = remapValue(expression.symbol) ?: return expression
+        assert(newValue.owner.isAssignable)
+        return expression.run { IrSetValueImpl(startOffset, endOffset, type, newValue, value, origin) }
+    }
+}
+
+open class ValueRemapper(private val map: Map<IrValueSymbol, IrValueSymbol>) : AbstractValueRemapper() {
+    override fun remapValue(oldValue: IrValueSymbol): IrValueSymbol? = map[oldValue]
+}