Move labeling into NameTables with labeling loops which contain escaped break

^KT-42262 fixed

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsLoweringPhases.kt

@@ -341,12 +341,6 @@ private val rangeContainsLoweringPhase = makeBodyLoweringPhase(
     description = "[Optimization] Optimizes calls to contains() for ClosedRanges"
 )
 
-private val loopWithBreakingSwitchLowering = makeBodyLoweringPhase(
-    { LoopWithBreakingSwitchLowering() },
-    name = "LoopWithBreakingSwitchLowering",
-    description = "Transform statement-like-expression nodes into pure-statement to make it easily transform into JS",
-)
-
 private val forLoopsLoweringPhase = makeBodyLoweringPhase(
     ::ForLoopsLowering,
     name = "ForLoopsLowering",
@@ -718,7 +712,6 @@ val loweringList = listOf<Lowering>(
     interopCallableReferenceLoweringPhase,
     returnableBlockLoweringPhase,
     rangeContainsLoweringPhase,
-    loopWithBreakingSwitchLowering,
     forLoopsLoweringPhase,
     primitiveCompanionLoweringPhase,
     propertyAccessorInlinerLoweringPhase,

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/LoopWithBreakingSwitchLowering.kt

@@ -1,51 +0,0 @@
-/*
- * Copyright 2010-2020 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.ir.backend.js.lower
-
-import org.jetbrains.kotlin.backend.common.BodyLoweringPass
-import org.jetbrains.kotlin.ir.declarations.IrDeclaration
-import org.jetbrains.kotlin.ir.declarations.IrFunction
-import org.jetbrains.kotlin.ir.expressions.IrBody
-import org.jetbrains.kotlin.ir.expressions.IrBreak
-import org.jetbrains.kotlin.ir.expressions.IrExpression
-import org.jetbrains.kotlin.ir.expressions.IrLoop
-import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
-import java.util.*
-
-class LoopWithBreakingSwitchLowering : BodyLoweringPass {
-
-    private val switchInLoopTransformer = LoopWithBreakingSwitchTransformer()
-
-    override fun lower(irBody: IrBody, container: IrDeclaration) {
-        when (container) {
-            is IrFunction -> {
-                container.accept(switchInLoopTransformer, null)
-            }
-        }
-    }
-}
-
-class LoopWithBreakingSwitchTransformer : IrElementTransformerVoid() {
-    private var counter: Int = 0
-
-    private val loopDeque: Deque<IrLoop> = LinkedList()
-
-    override fun visitBreak(jump: IrBreak): IrExpression {
-        val loop = loopDeque.firstOrNull()
-        loop?.label = loop?.label ?: makeLoopLabel()
-
-        return super.visitBreak(jump)
-    }
-
-    override fun visitLoop(loop: IrLoop): IrExpression {
-        loopDeque.push(loop)
-        return super.visitLoop(loop).apply {
-            loopDeque.pop()
-        }
-    }
-
-    private fun makeLoopLabel() = "\$l\$switch\$${counter++}"
-}

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/NameTables.kt

@@ -11,7 +11,10 @@ import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.backend.js.JsLoweredDeclarationOrigin
 import org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir.JsManglerIr
 import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.expressions.IrBreak
+import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrLoop
+import org.jetbrains.kotlin.ir.expressions.IrWhen
 import org.jetbrains.kotlin.ir.types.isUnit
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
@@ -21,6 +24,7 @@ import org.jetbrains.kotlin.js.naming.isES5IdentifierPart
 import org.jetbrains.kotlin.js.naming.isES5IdentifierStart
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.utils.addToStdlib.ifNotEmpty
+import java.util.*
 
 fun <T> mapToKey(declaration: T): String {
     return with(JsManglerIr) {
@@ -357,6 +361,8 @@ class NameTables(
     inner class LocalNameGenerator(parentDeclaration: IrDeclaration) : IrElementVisitorVoid {
         val table = NameTable<IrDeclaration>(globalNames)
 
+        private val breakableDeque: Deque<IrExpression> = LinkedList()
+
         init {
             localNames[parentDeclaration] = table
         }
@@ -373,21 +379,45 @@ class NameTables(
             super.visitDeclaration(declaration)
         }
 
-        override fun visitLoop(loop: IrLoop) {
-            val label = loop.label
-            if (label != null) {
-                localLoopNames.declareFreshName(loop, label)
-                loopNames[loop] = localLoopNames.names[loop]!!
+        override fun visitBreak(jump: IrBreak) {
+            val loop = jump.loop
+            if (loop != breakableDeque.firstOrNull()) {
+                persistLoopName(SYNTHETIC_LOOP_LABEL, loop)
             }
+
+            super.visitBreak(jump)
+        }
+
+        override fun visitWhen(expression: IrWhen) {
+            breakableDeque.push(expression)
+
+            super.visitWhen(expression)
+
+            breakableDeque.pop()
+        }
+
+        override fun visitLoop(loop: IrLoop) {
+            breakableDeque.push(loop)
+
             super.visitLoop(loop)
+
+            breakableDeque.pop()
+
+            val label = loop.label
+
+            if (label != null) {
+                persistLoopName(label, loop)
+            }
+        }
+
+        private fun persistLoopName(label: String, loop: IrLoop) {
+            localLoopNames.declareFreshName(loop, label)
+            loopNames[loop] = localLoopNames.names[loop]!!
         }
     }
 
     fun getNameForLoop(loop: IrLoop): String? =
-        if (loop.label == null)
-            null
-        else
-            loopNames[loop]!!
+        loopNames[loop]
 }
 
 
@@ -397,3 +427,5 @@ fun sanitizeName(name: String): String {
     val first = name.first().let { if (it.isES5IdentifierStart()) it else '_' }
     return first.toString() + name.drop(1).map { if (it.isES5IdentifierPart()) it else '_' }.joinToString("")
 }
+
+private const val SYNTHETIC_LOOP_LABEL = "\$l\$break"