Introduce KClass-based cache for KPackageFragment

* It is a heavy-weight object that is hard to compute
* It is being constructed each type _cached_ method ref is used in equals/hashCode
* Module name is deliberately ignored, corresponding doc is added where appropriate 

#KT-48136

Merge-request: KT-MR-6817
Merged-by: Vsevolod Tolstopyatov <qwwdfsad@gmail.com>

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java

@@ -41267,6 +41267,18 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/reflection"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
         }
 
+        @Test
+        @TestMetadata("jvmKPackageCaching.kt")
+        public void testJvmKPackageCaching() throws Exception {
+            runTest("compiler/testData/codegen/box/reflection/jvmKPackageCaching.kt");
+        }
+
+        @Test
+        @TestMetadata("jvmKTypeCaching.kt")
+        public void testJvmKTypeCaching() throws Exception {
+            runTest("compiler/testData/codegen/box/reflection/jvmKTypeCaching.kt");
+        }
+
         @Nested
         @TestMetadata("compiler/testData/codegen/box/reflection/annotations")
         @TestDataPath("$PROJECT_ROOT")

compiler/testData/codegen/box/reflection/jvmKPackageCaching.kt

@@ -0,0 +1,13 @@
+// TARGET_BACKEND: JVM_IR
+// FULL_JDK
+// WITH_REFLECT
+import kotlin.jvm.internal.*
+
+class A
+fun box(): String {
+    val pckg = Reflection.getOrCreateKotlinPackage(A::class.java)
+    System.gc()
+    val pckg2 = Reflection.getOrCreateKotlinPackage(A::class.java)
+    if (pckg === pckg2) return "OK"
+    return "Fail"
+}

compiler/testData/codegen/box/reflection/jvmKTypeCaching.kt

@@ -0,0 +1,13 @@
+// TARGET_BACKEND: JVM_IR
+// FULL_JDK
+// WITH_REFLECT
+
+class A
+
+fun box(): String {
+    val clz = A::class
+    System.gc()
+    val clz2 = A::class
+    if (clz === clz2) return "OK"
+    return "Fail"
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java

@@ -41267,6 +41267,18 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/reflection"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
         }
 
+        @Test
+        @TestMetadata("jvmKPackageCaching.kt")
+        public void testJvmKPackageCaching() throws Exception {
+            runTest("compiler/testData/codegen/box/reflection/jvmKPackageCaching.kt");
+        }
+
+        @Test
+        @TestMetadata("jvmKTypeCaching.kt")
+        public void testJvmKTypeCaching() throws Exception {
+            runTest("compiler/testData/codegen/box/reflection/jvmKTypeCaching.kt");
+        }
+
         @Nested
         @TestMetadata("compiler/testData/codegen/box/reflection/annotations")
         @TestDataPath("$PROJECT_ROOT")

core/reflection.jvm/src/kotlin/reflect/jvm/internal/ClassCaches.kt

@@ -5,13 +5,19 @@
 
 package kotlin.reflect.jvm.internal
 
+import kotlin.reflect.KDeclarationContainer
+
 
 private val K_CLASS_CACHE = createCache { KClassImpl(it) }
+private val K_PACKAGE_CACHE = createCache { KPackageImpl(it) }
 
 // This function is invoked on each reflection access to Java classes, properties, etc. Performance is critical here.
 @Suppress("UNCHECKED_CAST")
 internal fun <T : Any> getOrCreateKotlinClass(jClass: Class<T>): KClassImpl<T> = K_CLASS_CACHE.get(jClass) as KClassImpl<T>
 
-internal fun clearKClassCache() {
+internal fun <T : Any> getOrCreateKotlinPackage(jClass: Class<T>): KDeclarationContainer = K_PACKAGE_CACHE.get(jClass)
+
+internal fun clearCaches() {
     K_CLASS_CACHE.clear()
+    K_PACKAGE_CACHE.clear()
 }

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KPackageImpl.kt

@@ -37,7 +37,6 @@ import kotlin.reflect.jvm.internal.KDeclarationContainerImpl.MemberBelonginess.D
 
 internal class KPackageImpl(
     override val jClass: Class<*>,
-    @Suppress("unused") val usageModuleName: String? = null // may be useful for debug
 ) : KDeclarationContainerImpl() {
     private inner class Data : KDeclarationContainerImpl.Data() {
         private val kotlinClass: ReflectKotlinClass? by ReflectProperties.lazySoft {

core/reflection.jvm/src/kotlin/reflect/jvm/internal/ReflectionFactoryImpl.java

@@ -32,17 +32,18 @@ public class ReflectionFactoryImpl extends ReflectionFactory {
 
     @Override
     public KDeclarationContainer getOrCreateKotlinPackage(Class javaClass, String moduleName) {
-        return new KPackageImpl(javaClass, moduleName);
+        // moduleName is unused deliberately and only left in public ABI
+        return ClassCachesKt.getOrCreateKotlinPackage(javaClass);
     }
 
     @Override
     public KClass getOrCreateKotlinClass(Class javaClass) {
-        return KClassCacheKt.getOrCreateKotlinClass(javaClass);
+        return ClassCachesKt.getOrCreateKotlinClass(javaClass);
     }
 
     @Override
     public KClass getOrCreateKotlinClass(Class javaClass, String internalName) {
-        return KClassCacheKt.getOrCreateKotlinClass(javaClass);
+        return ClassCachesKt.getOrCreateKotlinClass(javaClass);
     }
 
     @Override
@@ -154,7 +155,7 @@ public class ReflectionFactoryImpl extends ReflectionFactory {
     // Misc
 
     public static void clearCaches() {
-        KClassCacheKt.clearKClassCache();
+        ClassCachesKt.clearCaches();
         ModuleByClassLoaderKt.clearModuleByClassLoaderCache();
     }
 }

libraries/stdlib/jvm/runtime/kotlin/jvm/internal/Reflection.java

@@ -52,6 +52,7 @@ public class Reflection {
     }
 
     public static KDeclarationContainer getOrCreateKotlinPackage(Class javaClass, String moduleName) {
+        // This signature cannot be removed as it is used in FunctionReferenceLowering.kt non-directly
         return factory.getOrCreateKotlinPackage(javaClass, moduleName);
     }