Reduce allocations in KotlinTarget and modifier checkers

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirModifierChecker.kt

@@ -6,7 +6,6 @@
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
 import org.jetbrains.kotlin.descriptors.annotations.KotlinTarget
-import org.jetbrains.kotlin.descriptors.annotations.KotlinTarget.*
 import org.jetbrains.kotlin.descriptors.annotations.KotlinTarget.Companion.classActualTargets
 import org.jetbrains.kotlin.fir.FirFakeSourceElementKind
 import org.jetbrains.kotlin.fir.FirSourceElement
@@ -53,9 +52,12 @@ object FirModifierChecker : FirBasicDeclarationChecker() {
         context: CheckerContext,
         reporter: DiagnosticReporter
     ) {
+        if (list.modifiers.isEmpty()) return
+
         // general strategy: report no more than one error and any number of warnings
         // therefore, a track of nodes with already reported errors should be kept
         val reportedNodes = hashSetOf<FirModifier<*>>()
+
         val actualTargets = getActualTargetList(owner).defaultTargets
 
         val parent = context.findClosest<FirDeclaration> {
@@ -65,17 +67,17 @@ object FirModifierChecker : FirBasicDeclarationChecker() {
         }
 
         val actualParents = when (parent) {
-            is FirAnonymousObject -> listOf(LOCAL_CLASS, CLASS)
+            is FirAnonymousObject -> KotlinTarget.LOCAL_CLASS_LIST
             is FirClass -> classActualTargets(
                 parent.classKind,
                 isInnerClass = (parent as? FirMemberDeclaration)?.isInner ?: false,
                 isCompanionObject = (parent as? FirRegularClass)?.isCompanion ?: false,
                 isLocalClass = parent.isLocal
             )
-            is FirPropertyAccessor -> listOf(if (parent.isSetter) PROPERTY_SETTER else PROPERTY_GETTER)
+            is FirPropertyAccessor -> if (parent.isSetter) KotlinTarget.PROPERTY_SETTER_LIST else KotlinTarget.PROPERTY_GETTER_LIST
-            is FirFunction -> listOf(FUNCTION)
+            is FirFunction -> KotlinTarget.FUNCTION_LIST
-            is FirEnumEntry -> listOf(ENUM_ENTRY, PROPERTY, FIELD)
+            is FirEnumEntry -> KotlinTarget.ENUM_ENTRY_LIST
-            else -> listOf(FILE)
+            else -> KotlinTarget.FILE_LIST
         }
 
         val modifiers = list.modifiers

compiler/frontend/src/org/jetbrains/kotlin/resolve/ModifiersChecker.kt

@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.KotlinTarget
-import org.jetbrains.kotlin.descriptors.annotations.KotlinTarget.*
 import org.jetbrains.kotlin.diagnostics.Errors
 import org.jetbrains.kotlin.lexer.KtKeywordToken
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
@@ -206,10 +205,10 @@ object ModifierCheckerCore {
                 isCompanionObject = parentDescriptor.isCompanionObject,
                 isLocalClass = DescriptorUtils.isLocal(parentDescriptor)
             )
-            is PropertySetterDescriptor -> listOf(PROPERTY_SETTER)
+            is PropertySetterDescriptor -> KotlinTarget.PROPERTY_SETTER_LIST
-            is PropertyGetterDescriptor -> listOf(PROPERTY_GETTER)
+            is PropertyGetterDescriptor -> KotlinTarget.PROPERTY_GETTER_LIST
-            is FunctionDescriptor -> listOf(FUNCTION)
+            is FunctionDescriptor -> KotlinTarget.FUNCTION_LIST
-            else -> listOf(FILE)
+            else -> KotlinTarget.FILE_LIST
         }
         val deprecatedParents = deprecatedParentTargetMap[modifierType]
         if (deprecatedParents != null && actualParents.any { it in deprecatedParents }) {

core/compiler.common/src/org/jetbrains/kotlin/descriptors/annotations/KotlinTarget.kt

@@ -76,37 +76,49 @@ enum class KotlinTarget(val description: String, val isDefault: Boolean = true)
         fun valueOrNull(name: String): KotlinTarget? = map[name]
 
         val DEFAULT_TARGET_SET: Set<KotlinTarget> = values().filter { it.isDefault }.toSet()
-
         val ALL_TARGET_SET: Set<KotlinTarget> = values().toSet()
 
+        val ANNOTATION_CLASS_LIST = listOf(ANNOTATION_CLASS, CLASS)
+        val LOCAL_CLASS_LIST = listOf(LOCAL_CLASS, CLASS)
+        val CLASS_LIST = listOf(CLASS_ONLY, CLASS)
+        val COMPANION_OBJECT_LIST = listOf(COMPANION_OBJECT, OBJECT, CLASS)
+        val OBJECT_LIST = listOf(OBJECT, CLASS)
+        val INTERFACE_LIST = listOf(INTERFACE, CLASS)
+        val ENUM_LIST = listOf(ENUM_CLASS, CLASS)
+        val ENUM_ENTRY_LIST = listOf(ENUM_ENTRY, PROPERTY, FIELD)
+        val PROPERTY_SETTER_LIST = listOf(PROPERTY_SETTER)
+        val PROPERTY_GETTER_LIST = listOf(PROPERTY_GETTER)
+        val FUNCTION_LIST = listOf(FUNCTION)
+        val FILE_LIST = listOf(FILE)
+
         fun classActualTargets(
             kind: ClassKind,
             isInnerClass: Boolean,
             isCompanionObject: Boolean,
             isLocalClass: Boolean
         ): List<KotlinTarget> = when (kind) {
-            ClassKind.ANNOTATION_CLASS -> listOf(ANNOTATION_CLASS, CLASS)
+            ClassKind.ANNOTATION_CLASS -> ANNOTATION_CLASS_LIST
             ClassKind.CLASS ->
                 // inner local classes should be CLASS_ONLY, not LOCAL_CLASS
                 if (!isInnerClass && isLocalClass) {
-                    listOf(LOCAL_CLASS, CLASS)
+                    LOCAL_CLASS_LIST
                 } else {
-                    listOf(CLASS_ONLY, CLASS)
+                    CLASS_LIST
                 }
             ClassKind.OBJECT ->
                 if (isCompanionObject) {
-                    listOf(COMPANION_OBJECT, OBJECT, CLASS)
+                    COMPANION_OBJECT_LIST
                 } else {
-                    listOf(OBJECT, CLASS)
+                    OBJECT_LIST
                 }
-            ClassKind.INTERFACE -> listOf(INTERFACE, CLASS)
+            ClassKind.INTERFACE -> INTERFACE_LIST
             ClassKind.ENUM_CLASS ->
                 if (isLocalClass) {
-                    listOf(LOCAL_CLASS, CLASS)
+                    LOCAL_CLASS_LIST
                 } else {
-                    listOf(ENUM_CLASS, CLASS)
+                    ENUM_LIST
                 }
-            ClassKind.ENUM_ENTRY -> listOf(ENUM_ENTRY, PROPERTY, FIELD)
+            ClassKind.ENUM_ENTRY -> ENUM_ENTRY_LIST
         }
 
         val USE_SITE_MAPPING: Map<AnnotationUseSiteTarget, KotlinTarget> = mapOf(