Implement proper contract for generated java.lang.Annotation.hashCode()

#KT-48606 Fixed

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

@@ -455,6 +455,11 @@ class IrBuiltInsOverFir(
             it.owner.name == OperatorNameConventions.TIMES && it.owner.valueParameters[0].type == intType
         }
 
+    override val intXorSymbol: IrSimpleFunctionSymbol
+        get() = intClass.functions.single {
+            it.owner.name == OperatorNameConventions.XOR && it.owner.valueParameters[0].type == intType
+        }
+
     override val extensionToString: IrSimpleFunctionSymbol by lazy {
         findFunctions(kotlinPackage, Name.identifier("toString")).first { function ->
             function.owner.extensionReceiverParameter?.let { receiver -> receiver.type == anyNType } ?: false

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

@@ -419,6 +419,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
                 runTest("compiler/testData/codegen/box/annotations/instances/annotationInstancesEmptyDefault.kt");
             }
 
+            @Test
+            @TestMetadata("annotationJvmHashCode.kt")
+            public void testAnnotationJvmHashCode() throws Exception {
+                runTest("compiler/testData/codegen/box/annotations/instances/annotationJvmHashCode.kt");
+            }
+
             @Test
             @TestMetadata("annotationToString.kt")
             public void testAnnotationToString() throws Exception {

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/AnnotationImplementationTransformer.kt

@@ -13,19 +13,19 @@ import org.jetbrains.kotlin.backend.common.ir.copyTo
 import org.jetbrains.kotlin.backend.common.ir.createImplicitParameterDeclarationWithWrappedDescriptor
 import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
 import org.jetbrains.kotlin.descriptors.Modality
-import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.builders.declarations.*
 import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.expressions.*
+import org.jetbrains.kotlin.ir.expressions.IrConstructorCall
+import org.jetbrains.kotlin.ir.expressions.IrExpression
+import org.jetbrains.kotlin.ir.expressions.IrGetValue
 import org.jetbrains.kotlin.ir.expressions.impl.IrConstructorCallImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrDelegatingConstructorCallImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrSetFieldImpl
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.classOrNull
-import org.jetbrains.kotlin.ir.types.isArray
 import org.jetbrains.kotlin.ir.types.isKClass
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
@@ -183,18 +183,13 @@ open class AnnotationImplementationTransformer(val context: BackendContext, val
     @Suppress("UNUSED_VARIABLE")
     fun implementEqualsAndHashCode(annotationClass: IrClass, implClass: IrClass, originalProps: List<IrProperty>, childProps: List<IrProperty>) {
         val creator = MethodsFromAnyGeneratorForLowerings(context, implClass, ANNOTATION_IMPLEMENTATION)
-        val generator =
+        val generator = AnnotationImplementationMemberGenerator(
-            creator.LoweringDataClassMemberGenerator(
+            context, implClass,
-                nameForToString = "@" + annotationClass.fqNameWhenAvailable!!.asString(),
+            nameForToString = "@" + annotationClass.fqNameWhenAvailable!!.asString(),
-                typeForEquals = annotationClass.defaultType
+        ) { type, a, b ->
-            ) { type, a, b ->
+            generatedEquals(this, type, a, b)
-                generatedEquals(this, type, a, b)
+        }
-            }
 
-        // Manual implementation of equals is required for two reasons:
-        // 1. `other` should be casted to interface instead of implementation
-        // 2. Properties should be retrieved using getters without accessing backing fields
-        //    (DataClassMembersGenerator typically tries to access fields)
         val eqFun = creator.createEqualsMethodDeclaration()
         generator.generateEqualsUsingGetters(eqFun, annotationClass.defaultType, originalProps)
 
@@ -208,3 +203,49 @@ open class AnnotationImplementationTransformer(val context: BackendContext, val
     open fun implementPlatformSpecificParts(annotationClass: IrClass, implClass: IrClass) {}
 }
 
+class AnnotationImplementationMemberGenerator(
+    backendContext: BackendContext,
+    irClass: IrClass,
+    val nameForToString: String,
+    val selectEquals: IrBlockBodyBuilder.(IrType, IrExpression, IrExpression) -> IrExpression,
+) : LoweringDataClassMemberGenerator(backendContext, irClass, ANNOTATION_IMPLEMENTATION) {
+
+    override fun IrClass.classNameForToString(): String = nameForToString
+
+    // From https://docs.oracle.com/javase/8/docs/api/java/lang/annotation/Annotation.html#equals-java.lang.Object-
+    // ---
+    // The hash code of an annotation is the sum of the hash codes of its members (including those with default values), as defined below:
+    // The hash code of an annotation member is (127 times the hash code of the member-name as computed by String.hashCode()) XOR the hash code of the member-value
+    override fun IrBuilderWithScope.shiftResultOfHashCode(irResultVar: IrVariable): IrExpression = irGet(irResultVar) // no default (* 31)
+
+    override fun getHashCodeOf(builder: IrBuilderWithScope, property: IrProperty, irValue: IrExpression): IrExpression = with(builder) {
+        val propertyValueHashCode = getHashCodeOf(property.backingField!!.type, irValue)
+        val propertyNameHashCode = getHashCodeOf(backendContext.irBuiltIns.stringType, irString(property.name.toString()))
+        val multiplied = irCallOp(context.irBuiltIns.intTimesSymbol, context.irBuiltIns.intType, propertyNameHashCode, irInt(127))
+        return irCallOp(context.irBuiltIns.intXorSymbol, context.irBuiltIns.intType, multiplied, propertyValueHashCode)
+    }
+
+    // Manual implementation of equals is required for two reasons:
+    // 1. `other` should be casted to interface instead of implementation
+    // 2. Properties should be retrieved using getters without accessing backing fields
+    //    (DataClassMembersGenerator typically tries to access fields)
+    fun generateEqualsUsingGetters(equalsFun: IrSimpleFunction, typeForEquals: IrType, properties: List<IrProperty>) = equalsFun.apply {
+        body = backendContext.createIrBuilder(symbol).irBlockBody {
+            val irType = typeForEquals
+            fun irOther() = irGet(valueParameters[0])
+            fun irThis() = irGet(dispatchReceiverParameter!!)
+            fun IrProperty.get(receiver: IrExpression) = irCall(getter!!).apply {
+                dispatchReceiver = receiver
+            }
+
+            +irIfThenReturnFalse(irNotIs(irOther(), irType))
+            val otherWithCast = irTemporary(irAs(irOther(), irType), "other_with_cast")
+            for (property in properties) {
+                val arg1 = property.get(irThis())
+                val arg2 = property.get(irGet(irType, otherWithCast.symbol))
+                +irIfThenReturnFalse(irNot(selectEquals(property.getter?.returnType ?: property.backingField!!.type, arg1, arg2)))
+            }
+            +irReturnTrue()
+        }
+    }
+}

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/MethodsFromAnyGeneratorForLowerings.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.backend.common.lower
 
 import org.jetbrains.kotlin.backend.common.BackendContext
+import org.jetbrains.kotlin.backend.common.lower.MethodsFromAnyGeneratorForLowerings.Companion.isHashCode
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
@@ -38,71 +39,6 @@ class MethodsFromAnyGeneratorForLowerings(val context: BackendContext, val irCla
         addValueParameter("other", context.irBuiltIns.anyNType)
     }
 
-    inner class LoweringDataClassMemberGenerator(
-        val nameForToString: String,
-        val typeForEquals: IrType,
-        val selectEquals: IrBlockBodyBuilder.(IrType, IrExpression, IrExpression) -> IrExpression,
-    ) :
-        DataClassMembersGenerator(
-            IrGeneratorContextBase(context.irBuiltIns),
-            context.ir.symbols.externalSymbolTable,
-            irClass,
-            origin
-        ) {
-
-        override fun declareSimpleFunction(startOffset: Int, endOffset: Int, functionDescriptor: FunctionDescriptor): IrFunction {
-            error("Descriptor API shouldn't be used in lowerings")
-        }
-
-        override fun generateSyntheticFunctionParameterDeclarations(irFunction: IrFunction) {
-            // no-op — irFunction from lowering should already have necessary parameters
-        }
-
-        override fun getProperty(parameter: ValueParameterDescriptor?, irValueParameter: IrValueParameter?): IrProperty? {
-            error("Descriptor API shouldn't be used in lowerings")
-        }
-
-        override fun transform(typeParameterDescriptor: TypeParameterDescriptor): IrType {
-            error("Descriptor API shouldn't be used in lowerings")
-        }
-
-        override fun getHashCodeFunctionInfo(type: IrType): HashCodeFunctionInfo {
-            val symbol = if (type.isArray() || type.isPrimitiveArray()) {
-                context.irBuiltIns.dataClassArrayMemberHashCodeSymbol
-            } else {
-                type.classOrNull?.functions?.singleOrNull { it.owner.isHashCode() } ?:
-                    context.irBuiltIns.anyClass.functions.single { it.owner.name.asString() == "hashCode" }
-            }
-            return object : HashCodeFunctionInfo {
-                override val symbol: IrSimpleFunctionSymbol = symbol
-
-                override fun commitSubstituted(irMemberAccessExpression: IrMemberAccessExpression<*>) {}
-            }
-        }
-
-        override fun IrClass.classNameForToString(): String = nameForToString
-
-        fun generateEqualsUsingGetters(equalsFun: IrSimpleFunction, typeForEquals: IrType, properties: List<IrProperty>) = equalsFun.apply {
-            body = this@MethodsFromAnyGeneratorForLowerings.context.createIrBuilder(symbol).irBlockBody {
-                val irType = typeForEquals
-                fun irOther() = irGet(valueParameters[0])
-                fun irThis() = irGet(dispatchReceiverParameter!!)
-                fun IrProperty.get(receiver: IrExpression) = irCall(getter!!).apply {
-                    dispatchReceiver = receiver
-                }
-
-                +irIfThenReturnFalse(irNotIs(irOther(), irType))
-                val otherWithCast = irTemporary(irAs(irOther(), irType), "other_with_cast")
-                for (property in properties) {
-                    val arg1 = property.get(irThis())
-                    val arg2 = property.get(irGet(irType, otherWithCast.symbol))
-                    +irIfThenReturnFalse(irNot(selectEquals(property.getter?.returnType ?: property.backingField!!.type, arg1, arg2)))
-                }
-                +irReturnTrue()
-            }
-        }
-    }
-
     companion object {
         fun IrFunction.isToString(): Boolean =
             name.asString() == "toString" && extensionReceiverParameter == null && valueParameters.isEmpty()
@@ -118,6 +54,53 @@ class MethodsFromAnyGeneratorForLowerings(val context: BackendContext, val irCla
 
         fun IrClass.collectOverridenSymbols(predicate: (IrFunction) -> Boolean): List<IrSimpleFunctionSymbol> =
             superTypes.mapNotNull { it.getClass()?.functions?.singleOrNull(predicate)?.symbol }
-
     }
-}
+}
+
+open class LoweringDataClassMemberGenerator(
+    val backendContext: BackendContext,
+    irClass: IrClass,
+    origin: IrDeclarationOrigin
+) :
+    DataClassMembersGenerator(
+        IrGeneratorContextBase(backendContext.irBuiltIns),
+        backendContext.ir.symbols.externalSymbolTable,
+        irClass,
+        origin
+    ) {
+
+    override fun declareSimpleFunction(startOffset: Int, endOffset: Int, functionDescriptor: FunctionDescriptor): IrFunction {
+        error("Descriptor API shouldn't be used in lowerings")
+    }
+
+    override fun generateSyntheticFunctionParameterDeclarations(irFunction: IrFunction) {
+        // no-op — irFunction from lowering should already have necessary parameters
+    }
+
+    override fun getProperty(parameter: ValueParameterDescriptor?, irValueParameter: IrValueParameter?): IrProperty? {
+        error("Descriptor API shouldn't be used in lowerings")
+    }
+
+    override fun transform(typeParameterDescriptor: TypeParameterDescriptor): IrType {
+        error("Descriptor API shouldn't be used in lowerings")
+    }
+
+    override fun getHashCodeFunctionInfo(type: IrType): HashCodeFunctionInfo {
+        val symbol = if (type.isArray() || type.isPrimitiveArray()) {
+            context.irBuiltIns.dataClassArrayMemberHashCodeSymbol
+        } else {
+            type.classOrNull?.functions?.singleOrNull { it.owner.isHashCode() }
+                ?: context.irBuiltIns.anyClass.functions.single { it.owner.name.asString() == "hashCode" }
+        }
+        return object : HashCodeFunctionInfo {
+            override val symbol: IrSimpleFunctionSymbol = symbol
+
+            override fun commitSubstituted(irMemberAccessExpression: IrMemberAccessExpression<*>) {}
+        }
+    }
+}
+
+
+
+
+

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrBuiltIns.kt

@@ -139,6 +139,7 @@ abstract class IrBuiltIns {
 
     abstract val intPlusSymbol: IrSimpleFunctionSymbol
     abstract val intTimesSymbol: IrSimpleFunctionSymbol
+    abstract val intXorSymbol: IrSimpleFunctionSymbol
 
     abstract val extensionToString: IrSimpleFunctionSymbol
     abstract val stringPlus: IrSimpleFunctionSymbol

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrBuiltInsOverDescriptors.kt

@@ -32,10 +32,7 @@ import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeBuilder
 import org.jetbrains.kotlin.ir.types.impl.buildSimpleType
 import org.jetbrains.kotlin.ir.types.impl.originalKotlinType
-import org.jetbrains.kotlin.ir.util.SymbolTable
+import org.jetbrains.kotlin.ir.util.*
-import org.jetbrains.kotlin.ir.util.TypeTranslator
-import org.jetbrains.kotlin.ir.util.functions
-import org.jetbrains.kotlin.ir.util.referenceClassifier
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.scopes.MemberScope
@@ -387,6 +384,11 @@ class IrBuiltInsOverDescriptors(
             KotlinTypeChecker.DEFAULT.equalTypes(it.valueParameters[0].type, int)
         }.let { symbolTable.referenceSimpleFunction(it) }
 
+    override val intXorSymbol: IrSimpleFunctionSymbol =
+        builtIns.int.unsubstitutedMemberScope.findFirstFunction("xor") {
+            KotlinTypeChecker.DEFAULT.equalTypes(it.valueParameters[0].type, int)
+        }.let { symbolTable.referenceSimpleFunction(it) }
+
     override val intPlusSymbol: IrSimpleFunctionSymbol =
         builtIns.int.unsubstitutedMemberScope.findFirstFunction("plus") {
             KotlinTypeChecker.DEFAULT.equalTypes(it.valueParameters[0].type, int)

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/DataClassMembersGenerator.kt

@@ -16,7 +16,9 @@ import org.jetbrains.kotlin.ir.expressions.IrMemberAccessExpression
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
 import org.jetbrains.kotlin.ir.expressions.mapTypeParameters
 import org.jetbrains.kotlin.ir.expressions.mapValueParameters
-import org.jetbrains.kotlin.ir.symbols.*
+import org.jetbrains.kotlin.ir.symbols.IrClassifierSymbol
+import org.jetbrains.kotlin.ir.symbols.IrConstructorSymbol
+import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.symbols.impl.IrVariableSymbolImpl
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.classifierOrNull
@@ -160,7 +162,7 @@ abstract class DataClassMembersGenerator(
             +irResultVar
 
             for (property in properties.drop(1)) {
-                val shiftedResult = irCallOp(context.irBuiltIns.intTimesSymbol, irIntType, irGet(irResultVar), irInt(31))
+                val shiftedResult = shiftResultOfHashCode(irResultVar)
                 val irRhs = irCallOp(context.irBuiltIns.intPlusSymbol, irIntType, shiftedResult, getHashCodeOfProperty(property))
                 +irSet(irResultVar.symbol, irRhs)
             }
@@ -175,30 +177,10 @@ abstract class DataClassMembersGenerator(
                         context.irBuiltIns.intType,
                         irGetProperty(irThis(), property),
                         irInt(0),
-                        getHashCodeOf(property, irGetProperty(irThis(), property))
+                        getHashCodeOf(this, property, irGetProperty(irThis(), property))
                     )
                 else ->
-                    getHashCodeOf(property, irGetProperty(irThis(), property))
+                    getHashCodeOf(this, property, irGetProperty(irThis(), property))
-            }
-        }
-
-        private fun getHashCodeOf(property: IrProperty, irValue: IrExpression): IrExpression {
-            val hashCodeFunctionInfo = getHashCodeFunctionInfo(property.backingField!!.type)
-            val hashCodeFunctionSymbol = hashCodeFunctionInfo.symbol
-
-            val hasDispatchReceiver = hashCodeFunctionSymbol.descriptor.dispatchReceiverParameter != null
-            return irCall(
-                hashCodeFunctionSymbol,
-                context.irBuiltIns.intType,
-                valueArgumentsCount = if (hasDispatchReceiver) 0 else 1,
-                typeArgumentsCount = 0
-            ).apply {
-                if (hasDispatchReceiver) {
-                    dispatchReceiver = irValue
-                } else {
-                    putValueArgument(0, irValue)
-                }
-                hashCodeFunctionInfo.commitSubstituted(this)
             }
         }
 
@@ -230,6 +212,32 @@ abstract class DataClassMembersGenerator(
         }
     }
 
+    protected open fun IrBuilderWithScope.shiftResultOfHashCode(irResultVar: IrVariable): IrExpression =
+        irCallOp(context.irBuiltIns.intTimesSymbol, context.irBuiltIns.intType, irGet(irResultVar), irInt(31))
+
+    protected open fun getHashCodeOf(builder: IrBuilderWithScope, property: IrProperty, irValue: IrExpression) =
+        builder.getHashCodeOf(property.backingField!!.type, irValue)
+
+    protected fun IrBuilderWithScope.getHashCodeOf(type: IrType, irValue: IrExpression): IrExpression {
+        val hashCodeFunctionInfo = getHashCodeFunctionInfo(type)
+        val hashCodeFunctionSymbol = hashCodeFunctionInfo.symbol
+        val hasDispatchReceiver = hashCodeFunctionSymbol.descriptor.dispatchReceiverParameter != null
+        return irCall(
+            hashCodeFunctionSymbol,
+            context.irBuiltIns.intType,
+            valueArgumentsCount = if (hasDispatchReceiver) 0 else 1,
+            typeArgumentsCount = 0
+        ).apply {
+            if (hasDispatchReceiver) {
+                dispatchReceiver = irValue
+            } else {
+                putValueArgument(0, irValue)
+            }
+            hashCodeFunctionInfo.commitSubstituted(this)
+        }
+    }
+
+
     fun getIrProperty(property: PropertyDescriptor): IrProperty =
         irPropertiesByDescriptor[property]
             ?: throw AssertionError("Class: ${irClass.descriptor}: unexpected property descriptor: $property")

compiler/testData/codegen/box/annotations/instances/annotationEqHc.kt

@@ -20,14 +20,14 @@ annotation class Foo(
     val bar: Bar
 )
 
-data class BarLike(val i:Int, val s: String, val f: Float)
+fun makeHC(name: String, value: Any) = (127 * name.hashCode()) xor value.hashCode()
 
 fun box(): String {
     val foo1 = Foo(42, "foo", arrayOf("a", "b"), intArrayOf(1,2), Bar::class, Bar(10, "bar", Float.NaN))
     val foo2 = Foo(42, "foo", arrayOf("a", "b"), intArrayOf(1,2), Bar::class, Bar(10, "bar", Float.NaN))
     if (foo1 != foo2) return "Failed equals ${foo1.toString()} ${foo2.toString()}"
-    val barlike = BarLike(10, "bar", Float.NaN)
+    val barlike = makeHC("i", 10) + makeHC("s", "bar") + makeHC("f", Float.NaN)
-    if (barlike.hashCode() != foo1.bar.hashCode()) return "Failed HC1"
+    if (barlike != foo1.bar.hashCode()) return "Failed HC1"
-    if (barlike.hashCode() != foo2.bar.hashCode()) return "Failed HC2"
+    if (barlike != foo2.bar.hashCode()) return "Failed HC2"
     return "OK"
 }

compiler/testData/codegen/box/annotations/instances/annotationJvmHashCode.kt

@@ -0,0 +1,35 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+// TARGET_BACKEND: JVM_IR
+
+// WITH_RUNTIME
+// !LANGUAGE: +InstantiationOfAnnotationClasses
+
+import kotlin.reflect.KClass
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue as assert
+
+annotation class ZeroArg()
+
+annotation class OneArg(val arg: String)
+
+annotation class ManyArg(val i: Int, val o: OneArg, val z: Boolean, val k: KClass<*>, val e: IntArray)
+
+@ZeroArg
+@OneArg("a")
+@ManyArg(42, OneArg("b"), true, OneArg::class, intArrayOf(1, 2, 3))
+class Target
+
+fun box(): String {
+    val reflectiveZero = Target::class.java.getAnnotation(ZeroArg::class.java)
+    val reflectiveOne = Target::class.java.getAnnotation(OneArg::class.java)
+    val reflectiveMany = Target::class.java.getAnnotation(ManyArg::class.java)
+
+    val createdZero = ZeroArg()
+    val createdOne = OneArg("a")
+    val createdMany = ManyArg(42, OneArg("b"), true, OneArg::class, intArrayOf(1, 2, 3))
+
+    assertEquals(reflectiveZero.hashCode(), createdZero.hashCode(), "zero")
+    assertEquals(reflectiveOne.hashCode(), createdOne.hashCode(), "one")
+    assertEquals(reflectiveMany.hashCode(), createdMany.hashCode(), "many")
+    return "OK"
+}

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

@@ -419,6 +419,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 runTest("compiler/testData/codegen/box/annotations/instances/annotationInstancesEmptyDefault.kt");
             }
 
+            @Test
+            @TestMetadata("annotationJvmHashCode.kt")
+            public void testAnnotationJvmHashCode() throws Exception {
+                runTest("compiler/testData/codegen/box/annotations/instances/annotationJvmHashCode.kt");
+            }
+
             @Test
             @TestMetadata("annotationToString.kt")
             public void testAnnotationToString() throws Exception {