FIR2IR: Avoid recreation of declarations

They may be previously created for fake overrides

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConverter.kt

@@ -198,12 +198,12 @@ class Fir2IrConverter(
                 processClassMembers(declaration)
             }
             is FirSimpleFunction -> {
-                declarationStorage.createIrFunction(
+                declarationStorage.getOrCreateIrFunction(
                     declaration, parent, isLocal = isLocal
                 )
             }
             is FirProperty -> {
-                declarationStorage.createIrProperty(
+                declarationStorage.getOrCreateProperty(
                     declaration, parent, isLocal = isLocal
                 )
             }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt

@@ -7,11 +7,8 @@ package org.jetbrains.kotlin.fir.backend
 
 import org.jetbrains.kotlin.KtNodeTypes
 import org.jetbrains.kotlin.builtins.StandardNames.BUILT_INS_PACKAGE_FQ_NAMES
-import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.descriptors.*
-import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.fir.FirAnnotationContainer
-import org.jetbrains.kotlin.descriptors.Visibilities
-import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.fir.backend.generators.AnnotationGenerator
 import org.jetbrains.kotlin.fir.backend.generators.DelegatedMemberGenerator
 import org.jetbrains.kotlin.fir.declarations.*
@@ -30,6 +27,7 @@ import org.jetbrains.kotlin.fir.lazy.Fir2IrLazySimpleFunction
 import org.jetbrains.kotlin.fir.render
 import org.jetbrains.kotlin.fir.resolve.firProvider
 import org.jetbrains.kotlin.fir.resolve.firSymbolProvider
+import org.jetbrains.kotlin.fir.resolve.inference.isSuspendFunctionType
 import org.jetbrains.kotlin.fir.resolve.isKFunctionInvoke
 import org.jetbrains.kotlin.fir.symbols.*
 import org.jetbrains.kotlin.fir.symbols.impl.*
@@ -51,8 +49,6 @@ import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedContainerSource
-import org.jetbrains.kotlin.descriptors.DescriptorVisibility
-import org.jetbrains.kotlin.fir.resolve.inference.isSuspendFunctionType
 
 @OptIn(ObsoleteDescriptorBasedAPI::class)
 class Fir2IrDeclarationStorage(
@@ -390,6 +386,15 @@ class Fir2IrDeclarationStorage(
         return symbolTable.declareSimpleFunction(signature, { Fir2IrSimpleFunctionSymbol(signature, containerSource) }, factory)
     }
 
+    fun getOrCreateIrFunction(
+        function: FirFunction<*>,
+        irParent: IrDeclarationParent?,
+        isLocal: Boolean = false,
+    ): IrSimpleFunction {
+        getCachedIrFunction(function)?.let { return it }
+        return createIrFunction(function, irParent, isLocal = isLocal)
+    }
+
     fun createIrFunction(
         function: FirFunction<*>,
         irParent: IrDeclarationParent?,
@@ -653,6 +658,15 @@ class Fir2IrDeclarationStorage(
         return symbolTable.declareProperty(signature, { Fir2IrPropertySymbol(signature, containerSource) }, factory)
     }
 
+    fun getOrCreateProperty(
+        property: FirProperty,
+        irParent: IrDeclarationParent?,
+        isLocal: Boolean = false,
+    ): IrProperty {
+        getCachedIrProperty(property)?.let { return it }
+        return createIrProperty(property, irParent, isLocal = isLocal)
+    }
+
     fun createIrProperty(
         property: FirProperty,
         irParent: IrDeclarationParent?,