Fir2Ir: pass Fir2IrExtensions to backend

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

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.ir.util
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.*
 import org.jetbrains.kotlin.ir.builders.declarations.addConstructor
+import org.jetbrains.kotlin.ir.builders.declarations.buildClass
 import org.jetbrains.kotlin.ir.builders.declarations.buildReceiverParameter
 import org.jetbrains.kotlin.ir.builders.declarations.buildTypeParameter
 import org.jetbrains.kotlin.ir.declarations.*
@@ -986,6 +987,18 @@ fun IrClass.createImplicitParameterDeclarationWithWrappedDescriptor() {
     thisReceiver = buildReceiverParameter(this, IrDeclarationOrigin.INSTANCE_RECEIVER, symbol.typeWithParameters(typeParameters))
 }
 
+fun IrFactory.createSpecialAnnotationClass(fqn: FqName, parent: IrPackageFragment) =
+    buildClass {
+        kind = ClassKind.ANNOTATION_CLASS
+        name = fqn.shortName()
+    }.apply {
+        createImplicitParameterDeclarationWithWrappedDescriptor()
+        this.parent = parent
+        addConstructor {
+            isPrimary = true
+        }
+    }
+
 @Suppress("UNCHECKED_CAST")
 fun isElseBranch(branch: IrBranch) = branch is IrElseBranch || ((branch.condition as? IrConst<Boolean>)?.value == true)
 
@@ -1242,4 +1255,4 @@ private fun computeAllOverridden(function: IrSimpleFunction, result: MutableSet<
 }
 
 fun IrBuiltIns.getKFunctionType(returnType: IrType, parameterTypes: List<IrType>) =
-    kFunctionN(parameterTypes.size).typeWith(parameterTypes + returnType)
+    kFunctionN(parameterTypes.size).typeWith(parameterTypes + returnType)