[Serialization] Introduce utility for generation of IR annotation calls

plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/IrBuilderWithPluginContext.kt

@@ -9,6 +9,7 @@ import org.jetbrains.kotlin.backend.common.lower.DeclarationIrBuilder
 import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.builders.declarations.*
@@ -141,6 +142,13 @@ interface IrBuilderWithPluginContext {
         return prop
     }
 
+    fun IrElement.createAnnotationCallWithoutArgs(annotationSymbol: IrClassSymbol): IrConstructorCall {
+        val annotationCtor = annotationSymbol.constructors.single { it.owner.isPrimary }
+        val annotationType = annotationSymbol.defaultType
+
+        return IrConstructorCallImpl.fromSymbolOwner(startOffset, endOffset, annotationType, annotationCtor)
+    }
+
     fun IrClass.addValPropertyWithJvmField(
         type: IrType,
         name: Name,
@@ -153,11 +161,7 @@ interface IrBuilderWithPluginContext {
                 val resultExpression = addAndGetLastExpression(initializerBuilder)
                 +irSetField(irGet(thisReceiver!!), field, resultExpression)
             }
-
+            field.annotations += createAnnotationCallWithoutArgs(compilerContext.jvmFieldClassSymbol)
-            val annotationCtor = compilerContext.jvmFieldClassSymbol.constructors.single { it.owner.isPrimary }
-            val annotationType = compilerContext.jvmFieldClassSymbol.defaultType
-
-            field.annotations += IrConstructorCallImpl.fromSymbolOwner(startOffset, endOffset, annotationType, annotationCtor)
         }
     }
 
@@ -177,11 +181,7 @@ interface IrBuilderWithPluginContext {
                 field.endOffset
             )
             field.initializer = IrExpressionBodyImpl(builder.initializer())
-
+            field.annotations += createAnnotationCallWithoutArgs(compilerContext.jvmFieldClassSymbol)
-            val annotationCtor = compilerContext.jvmFieldClassSymbol.constructors.single { it.owner.isPrimary }
-            val annotationType = compilerContext.jvmFieldClassSymbol.defaultType
-
-            field.annotations += IrConstructorCallImpl.fromSymbolOwner(startOffset, endOffset, annotationType, annotationCtor)
         }
     }
 

plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializableCompanionIrGenerator.kt

@@ -87,12 +87,7 @@ class SerializableCompanionIrGenerator(
         }
 
         val annotationClass = compilerContext.referenceClass(SerializationAnnotations.namedCompanionClassId) ?: return
-
+        val annotationCall = irClass.createAnnotationCallWithoutArgs(annotationClass)
-        val annotationCtor = annotationClass.constructors.single { it.owner.isPrimary }
-        val annotationType = annotationClass.defaultType
-
-        val annotationCall = IrConstructorCallImpl.fromSymbolOwner(irClass.startOffset, irClass.endOffset, annotationType, annotationCtor)
-
         compilerContext.metadataDeclarationRegistrar.addMetadataVisibleAnnotationsToElement(irClass, annotationCall)
     }