[IR] Outline the main logic in annotation-related helpers

Prefer smaller inline functions, because otherwise if they become
hot spots, they will complicate performance analysis, and actually
might make everything slower because of low inlining threshold in
HotSpot.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/IrUtils.kt

@@ -381,18 +381,27 @@ fun IrConstructorCall.getAnnotationStringValue(name: String): String {
     return (getValueArgument(parameter.index) as IrConst<*>).value as String
 }
 
-inline fun <reified T> IrConstructorCall.getAnnotationValueOrNull(name: String): T? {
+inline fun <reified T> IrConstructorCall.getAnnotationValueOrNull(name: String): T? =
+    getAnnotationValueOrNullImpl(name) as T?
+
+@PublishedApi
+internal fun IrConstructorCall.getAnnotationValueOrNullImpl(name: String): Any? {
     val parameter = symbol.owner.valueParameters.atMostOne { it.name.asString() == name }
-    return parameter?.let { getValueArgument(it.index)?.let { (it as IrConst<*>).value as T } }
+    val argument = parameter?.let { getValueArgument(it.index) }
+    return (argument as IrConst<*>?)?.value
 }
 
-inline fun <reified T> IrDeclaration.getAnnotationArgumentValue(fqName: FqName, argumentName: String): T? {
+inline fun <reified T> IrDeclaration.getAnnotationArgumentValue(fqName: FqName, argumentName: String): T? =
+    getAnnotationArgumentValueImpl(fqName, argumentName) as T?
+
+@PublishedApi
+internal fun IrDeclaration.getAnnotationArgumentValueImpl(fqName: FqName, argumentName: String): Any? {
     val annotation = this.annotations.findAnnotation(fqName) ?: return null
     for (index in 0 until annotation.valueArgumentsCount) {
         val parameter = annotation.symbol.owner.valueParameters[index]
-        if (parameter.name == Name.identifier(argumentName)) {
+        if (parameter.name.asString() == argumentName) {
-            val actual = annotation.getValueArgument(index) as? IrConst<*> ?: return null
+            val actual = annotation.getValueArgument(index) as? IrConst<*>
-            return actual.value as T
+            return actual?.value
         }
     }
     return null