Fir2IrClassifierStorage: don't calculate signature in registerClass

compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/pipeline/convertToIr.kt

@@ -45,6 +45,7 @@ fun FirSession.convertToIr(
         FirJvmKotlinMangler(this), JvmIrMangler, IrFactoryImpl,
         FirJvmVisibilityConverter,
         Fir2IrJvmSpecialAnnotationSymbolProvider(),
-        irGeneratorExtensions
+        irGeneratorExtensions,
+        generateSignatures = false
     )
 }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrClassifierStorage.kt

@@ -22,7 +22,6 @@ import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
 import org.jetbrains.kotlin.fir.types.FirTypeRef
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
-import org.jetbrains.kotlin.ir.builders.declarations.UNDEFINED_PARAMETER_INDEX
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.IrExternalPackageFragmentImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrEnumConstructorCallImpl
@@ -35,6 +34,7 @@ import org.jetbrains.kotlin.ir.util.constructors
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.name.StandardClassIds
+import org.jetbrains.kotlin.utils.addToStdlib.runUnless
 
 class Fir2IrClassifierStorage(
     private val components: Fir2IrComponents
@@ -292,14 +292,14 @@ class Fir2IrClassifierStorage(
         predefinedOrigin: IrDeclarationOrigin? = null
     ): IrClass {
         val visibility = regularClass.visibility
-        val modality = if (regularClass.classKind == ClassKind.ENUM_CLASS) {
-            regularClass.enumClassModality()
-        } else if (regularClass.classKind == ClassKind.ANNOTATION_CLASS) {
-            Modality.OPEN
-        } else {
-            regularClass.modality ?: Modality.FINAL
+        val modality = when (regularClass.classKind) {
+            ClassKind.ENUM_CLASS -> regularClass.enumClassModality()
+            ClassKind.ANNOTATION_CLASS -> Modality.OPEN
+            else -> regularClass.modality ?: Modality.FINAL
+        }
+        val signature = runUnless(regularClass.isLocal || !generateSignatures) {
+            signatureComposer.composeSignature(regularClass)
         }
-        val signature = if (regularClass.isLocal) null else signatureComposer.composeSignature(regularClass)
         val irClass = regularClass.convertWithOffsets { startOffset, endOffset ->
             declareIrClass(signature) { symbol ->
                 irFactory.createClass(

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrComponents.kt

@@ -43,4 +43,5 @@ interface Fir2IrComponents {
     val delegatedMemberGenerator: DelegatedMemberGenerator
 
     val extensions: Fir2IrExtensions
+    val generateSignatures: Boolean
 }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrComponentsStorage.kt

@@ -25,6 +25,7 @@ class Fir2IrComponentsStorage(
     override val irFactory: IrFactory,
     override val signatureComposer: FirBasedSignatureComposer,
     override val extensions: Fir2IrExtensions,
+    override val generateSignatures: Boolean
 ) : Fir2IrComponents {
 
     override lateinit var converter: Fir2IrConverter

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConverter.kt

@@ -396,7 +396,6 @@ class Fir2IrConverter(
             }
         }
 
-        @OptIn(ObsoleteDescriptorBasedAPI::class)
         fun createModuleFragment(
             session: FirSession,
             scopeSession: ScopeSession,
@@ -409,13 +408,16 @@ class Fir2IrConverter(
             irFactory: IrFactory,
             visibilityConverter: Fir2IrVisibilityConverter,
             specialSymbolProvider: Fir2IrSpecialSymbolProvider,
-            irGenerationExtensions: Collection<IrGenerationExtension>
+            irGenerationExtensions: Collection<IrGenerationExtension>,
+            generateSignatures: Boolean
         ): Fir2IrResult {
             val moduleDescriptor = FirModuleDescriptor(session)
             val signatureComposer = FirBasedSignatureComposer(mangler)
             val wrappedSignaturer = WrappedDescriptorSignatureComposer(signaturer, signatureComposer)
             val symbolTable = SymbolTable(wrappedSignaturer, irFactory)
-            val components = Fir2IrComponentsStorage(session, scopeSession, symbolTable, irFactory, signatureComposer, fir2IrExtensions)
+            val components = Fir2IrComponentsStorage(
+                session, scopeSession, symbolTable, irFactory, signatureComposer, fir2IrExtensions, generateSignatures
+            )
             val converter = Fir2IrConverter(moduleDescriptor, components)
 
             components.converter = converter