[IR] Enable -Xvalue-classes flag

Signed-off-by: Evgeniy.Zhelenskiy <Evgeniy.Zhelenskiy@jetbrains.com>

#KT-1179

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JVMCompilerArguments.kt

@@ -546,6 +546,12 @@ Also sets `-jvm-target` value equal to the selected JDK version"""
     )
     var oldInnerClassesLogic: Boolean by FreezableVar(false)
 
+    @Argument(
+        value = "-Xvalue-classes",
+        description = "Enable experimental value classes"
+    )
+    var valueClasses: Boolean by FreezableVar(false)
+
     override fun configureAnalysisFlags(collector: MessageCollector, languageVersion: LanguageVersion): MutableMap<AnalysisFlag<*>, Any> {
         val result = super.configureAnalysisFlags(collector, languageVersion)
         result[JvmAnalysisFlags.strictMetadataVersionSemantics] = strictMetadataVersionSemantics
@@ -581,6 +587,9 @@ Also sets `-jvm-target` value equal to the selected JDK version"""
             result[LanguageFeature.ForbidSuperDelegationToAbstractFakeOverride] = LanguageFeature.State.ENABLED
             result[LanguageFeature.AbstractClassMemberNotImplementedWithIntermediateAbstractClass] = LanguageFeature.State.ENABLED
         }
+        if (valueClasses) {
+            result[LanguageFeature.ValueClasses] = LanguageFeature.State.ENABLED
+        }
         return result
     }
 

compiler/testData/cli/jvm/extraHelp.out

@@ -157,6 +157,7 @@ where advanced options include:
   -Xuse-type-table           Use type table in metadata serialization
   -Xvalidate-bytecode        Validate generated JVM bytecode before and after optimizations
   -Xvalidate-ir              Validate IR before and after lowering
+  -Xvalue-classes            Enable experimental value classes
   -Xallow-any-scripts-in-source-roots
                              Allow to compile any scripts along with regular Kotlin sources
   -Xallow-kotlin-package     Allow compiling code in package 'kotlin' and allow not requiring kotlin.stdlib in module-info

jps/jps-common/test/CompilerArgumentsContentProspectorTest.kt

@@ -165,6 +165,7 @@ class CompilerArgumentsContentProspectorTest {
             K2JVMCompilerArguments::noUnifiedNullChecks,
             K2JVMCompilerArguments::useOldInlineClassesManglingScheme,
             K2JVMCompilerArguments::enableJvmPreview,
+            K2JVMCompilerArguments::valueClasses,
         )
 
         private val k2JVMCompilerArgumentsStringProperties = commonCompilerArgumentsStringProperties + listOf(