[JS IR] local var clashes

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

@@ -5,10 +5,8 @@
 
 package org.jetbrains.kotlin.ir.backend.js.utils
 
-import org.jetbrains.kotlin.ir.declarations.IrDeclarationWithName
-import org.jetbrains.kotlin.ir.declarations.IrFile
-import org.jetbrains.kotlin.ir.declarations.IrFunction
-import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
+import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.IrLoop
 import org.jetbrains.kotlin.ir.expressions.IrReturnableBlock
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
@@ -49,20 +47,28 @@ class JsGenerationContext(
         )
     }
 
+    private val nameCache = mutableMapOf<IrElement, JsName>()
+
     fun getNameForValueDeclaration(declaration: IrDeclarationWithName): JsName {
-        val name = localNames!!.variableNames.names[declaration]
-            ?: error("Variable name is not found ${declaration.name}")
-        return JsName(name, false)
+        return nameCache.getOrPut(declaration) {
+            val name = localNames!!.variableNames.names[declaration]
+                ?: error("Variable name is not found ${declaration.name}")
+            JsName(name, true)
+        }
     }
 
     fun getNameForLoop(loop: IrLoop): JsName? {
-        val name = localNames!!.localLoopNames.names[loop] ?: return null
-        return JsName(name, false)
+        return nameCache.getOrPut(loop) {
+            val name = localNames!!.localLoopNames.names[loop] ?: return null
+            JsName(name, true)
+        }
     }
 
     fun getNameForReturnableBlock(block: IrReturnableBlock): JsName? {
-        val name = localNames!!.localReturnableBlockNames.names[block] ?: return null
-        return JsName(name, false)
+        return nameCache.getOrPut(block) {
+            val name = localNames!!.localReturnableBlockNames.names[block] ?: return null
+            return JsName(name, true)
+        }
     }
 
     fun checkIfJsCode(symbol: IrFunctionSymbol): Boolean = symbol == staticContext.backendContext.intrinsics.jsCode