.kotlin.kotlin-compiler.1.3.11.source-code.Eliminator.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.js.dce
import org.jetbrains.kotlin.js.backend.ast.*
class Eliminator(private val analysisResult: AnalysisResult) : JsVisitorWithContextImpl() {
override fun visit(x: JsVars.JsVar, ctx: JsContext<*>): Boolean = removeIfNecessary(x, ctx)
override fun visit(x: JsExpressionStatement, ctx: JsContext<*>): Boolean = removeIfNecessary(x, ctx)
override fun visit(x: JsReturn, ctx: JsContext<*>): Boolean = removeIfNecessary(x, ctx)
private fun removeIfNecessary(x: JsNode, ctx: JsContext<*>): Boolean {
if (x in analysisResult.astNodesToEliminate) {
ctx.removeMe()
return false
}
val node = analysisResult.nodeMap[x]?.original
return if (!isUsed(node)) {
ctx.removeMe()
false
}
else {
true
}
}
override fun endVisit(x: JsVars, ctx: JsContext<*>) {
if (x.vars.isEmpty()) {
ctx.removeMe()
}
}
private fun isUsed(node: Context.Node?): Boolean = node == null || node.declarationReachable
}