[Test] Add handler for dumping preprocessed inline functions

^KT-80645

Author: mpiekutowski

compiler/tests-common-new/testFixtures/org/jetbrains/kotlin/test/backend/handlers/IrPreprocessedInlineFunctionDumpHandler.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2010-2025 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.test.backend.handlers
+
+import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
+import org.jetbrains.kotlin.ir.util.DumpIrTreeOptions
+import org.jetbrains.kotlin.ir.util.callableId
+import org.jetbrains.kotlin.ir.util.dump
+import org.jetbrains.kotlin.ir.util.preparedInlineFunctionCopies
+import org.jetbrains.kotlin.test.backend.ir.IrBackendInput
+import org.jetbrains.kotlin.test.directives.CodegenTestDirectives.DUMP_IR_OF_PREPROCESSED_INLINE_FUNCTIONS
+import org.jetbrains.kotlin.test.model.BackendKind
+import org.jetbrains.kotlin.test.model.TestModule
+import org.jetbrains.kotlin.test.services.TestServices
+import org.jetbrains.kotlin.test.services.moduleStructure
+import org.jetbrains.kotlin.test.utils.MultiModuleInfoDumper
+import org.jetbrains.kotlin.test.utils.withExtension
+import java.lang.StringBuilder
+
+private const val PREPROCESSED_INLINE_FUNCTIONS_EXTENSION = "preprocessed.ir.txt"
+
+class IrPreprocessedInlineFunctionDumpHandler(
+    testServices: TestServices,
+    artifactKind: BackendKind<IrBackendInput>,
+) : AbstractIrHandler(testServices, artifactKind) {
+    private val dumper = MultiModuleInfoDumper()
+
+    override fun processModule(
+        module: TestModule,
+        info: IrBackendInput,
+    ) {
+        if (DUMP_IR_OF_PREPROCESSED_INLINE_FUNCTIONS !in module.directives) return
+
+        val functionsToDump = info.irModuleFragment.preparedInlineFunctionCopies?.takeIf { it.isNotEmpty() } ?: return
+        val builder = dumper.builderForModule(module)
+        val dumpOptions = DumpIrTreeOptions(printFilePath = false)
+
+        builder.append("Module: ${module.name}\n")
+        functionsToDump.forEach { it.dumpWithCallableId(builder, dumpOptions) }
+    }
+
+    override fun processAfterAllModules(someAssertionWasFailed: Boolean) {
+        if (dumper.isEmpty()) return
+        val expectedFile = testServices.moduleStructure.originalTestDataFiles.first().withExtension(PREPROCESSED_INLINE_FUNCTIONS_EXTENSION)
+        assertions.assertEqualsToFile(expectedFile, dumper.generateResultingDump())
+    }
+
+    private fun IrSimpleFunction.dumpWithCallableId(stringBuilder: StringBuilder, dumpOptions: DumpIrTreeOptions) {
+        stringBuilder.append("// CallableId=$callableId\n")
+        stringBuilder.append(dump(dumpOptions))
+    }
+}

compiler/tests-common-new/testFixtures/org/jetbrains/kotlin/test/directives/CodegenTestDirectives.kt

@@ -118,6 +118,10 @@ object CodegenTestDirectives : SimpleDirectivesContainer() {
         description = "Dumps generated backend IR after inlining (enables ${IrTextDumpHandler::class} after inlining)"
     )
 
+    val DUMP_IR_OF_PREPROCESSED_INLINE_FUNCTIONS by directive(
+        description = "Dumps generated backend IR of preprocessed inline functions (enables ${IrPreprocessedInlineFunctionDumpHandler::class})"
+    )
+
     val DUMP_EXTERNAL_CLASS by stringDirective(
         description = "Specifies names of external classes which IR should be dumped"
     )