org.jetbrains.kotlin.backend.jvm.lower.JvmPropertiesLowering.kt Maven / Gradle / Ivy
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/*
* Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
package org.jetbrains.kotlin.backend.jvm.lower
import org.jetbrains.kotlin.backend.common.FileLoweringPass
import org.jetbrains.kotlin.backend.common.IrElementTransformerVoidWithContext
import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
import org.jetbrains.kotlin.backend.common.phaser.PhaseDescription
import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
import org.jetbrains.kotlin.backend.jvm.JvmLoweredDeclarationOrigin
import org.jetbrains.kotlin.backend.jvm.getRequiresMangling
import org.jetbrains.kotlin.backend.jvm.hasMangledReturnType
import org.jetbrains.kotlin.backend.jvm.ir.eraseTypeParameters
import org.jetbrains.kotlin.backend.jvm.ir.needsAccessor
import org.jetbrains.kotlin.config.LanguageFeature
import org.jetbrains.kotlin.descriptors.ClassKind
import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
import org.jetbrains.kotlin.descriptors.DescriptorVisibility
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.buildFun
import org.jetbrains.kotlin.ir.declarations.*
import org.jetbrains.kotlin.ir.expressions.IrCall
import org.jetbrains.kotlin.ir.expressions.IrExpression
import org.jetbrains.kotlin.ir.expressions.IrFieldAccessExpression
import org.jetbrains.kotlin.ir.expressions.impl.IrGetFieldImpl
import org.jetbrains.kotlin.ir.types.IrType
import org.jetbrains.kotlin.ir.types.classifierOrNull
import org.jetbrains.kotlin.ir.types.isSubtypeOfClass
import org.jetbrains.kotlin.ir.types.makeNullable
import org.jetbrains.kotlin.ir.util.*
import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
import org.jetbrains.kotlin.load.java.JvmAbi
import org.jetbrains.kotlin.name.Name
import org.jetbrains.kotlin.utils.addIfNotNull
@PhaseDescription(
name = "Properties",
description = "Move fields and accessors for properties to their classes, " +
"replace calls to default property accessors with field accesses, " +
"remove unused accessors and create synthetic methods for property annotations"
)
internal class JvmPropertiesLowering(
private val backendContext: JvmBackendContext
) : IrElementTransformerVoidWithContext(), FileLoweringPass {
override fun lower(irFile: IrFile) {
irFile.accept(this, null)
}
override fun visitClassNew(declaration: IrClass): IrStatement {
declaration.transformChildrenVoid(this)
declaration.transformDeclarationsFlat { if (it is IrProperty) lowerProperty(it, declaration.kind) else null }
return declaration
}
override fun visitCall(expression: IrCall): IrExpression {
val simpleFunction = expression.symbol.owner
val property = simpleFunction.correspondingPropertySymbol?.owner ?: return super.visitCall(expression)
expression.transformChildrenVoid()
if (shouldSubstituteAccessorWithField(property, simpleFunction) ||
isDefaultAccessorForCompanionPropertyBackingFieldOnCurrentClass(property, simpleFunction)
) {
backendContext.createIrBuilder(currentScope!!.scope.scopeOwnerSymbol, expression.startOffset, expression.endOffset).apply {
return when (simpleFunction) {
property.getter -> substituteGetter(property, expression)
property.setter -> substituteSetter(property, expression)
else -> error("Orphaned property getter/setter: ${simpleFunction.render()}")
}
}
}
return expression
}
private fun isDefaultAccessorForCompanionPropertyBackingFieldOnCurrentClass(
property: IrProperty,
function: IrSimpleFunction
): Boolean {
if (function.origin != IrDeclarationOrigin.DEFAULT_PROPERTY_ACCESSOR) return false
if (property.isLateinit) return false
// If this code could end up inlined in another class (either an inline function or an
// inlined lambda in an inline function) use the companion object accessor. Otherwise,
// we could break binary compatibility if we only recompile the class with the companion
// object and change to non-default field accessors. The inlined code would still attempt
// to get the backing field which would no longer exist.
val inInlineFunctionScope = allScopes.any { scope -> (scope.irElement as? IrFunction)?.isInline ?: false }
if (inInlineFunctionScope) return false
val backingField = property.resolveFakeOverrideOrFail().backingField
return backingField?.parent == currentClass?.irElement &&
backingField?.origin == JvmLoweredDeclarationOrigin.COMPANION_PROPERTY_BACKING_FIELD
}
private fun IrBuilderWithScope.substituteSetter(irProperty: IrProperty, expression: IrCall): IrExpression {
val backingField = irProperty.resolveFakeOverrideOrFail().backingField!!
return patchReceiver(
irSetField(
patchFieldAccessReceiver(expression, irProperty),
backingField,
expression.getValueArgument(0)!!
)
)
}
private fun IrBuilderWithScope.substituteGetter(irProperty: IrProperty, expression: IrCall): IrExpression {
val backingField = irProperty.resolveFakeOverrideOrFail().backingField!!
val patchedReceiver = patchFieldAccessReceiver(expression, irProperty)
return if (irProperty.isLateinit) {
irBlock {
val fieldType = expression.type.makeNullable()
val tmpVal = irTemporary(IrGetFieldImpl(startOffset, endOffset, backingField.symbol, fieldType, patchedReceiver))
+irIfNull(
expression.type,
irGet(tmpVal),
backendContext.throwUninitializedPropertyAccessException(this, backingField.name.asString()),
irGet(tmpVal)
)
}
} else {
IrGetFieldImpl(startOffset, endOffset, backingField.symbol, expression.type, patchedReceiver)
}
}
private fun IrBuilderWithScope.patchFieldAccessReceiver(expression: IrCall, irProperty: IrProperty): IrExpression? {
val receiver = expression.dispatchReceiver
if (receiver != null) {
val propertyParent = irProperty.parent
if (propertyParent is IrClass &&
receiver.type.classifierOrNull?.isSubtypeOfClass(propertyParent.symbol) != true &&
expression.superQualifierSymbol == null
) {
return irImplicitCast(receiver, propertyParent.defaultType)
}
}
return receiver
}
private fun IrBuilderWithScope.patchReceiver(expression: IrFieldAccessExpression): IrExpression =
if (expression.symbol.owner.isStatic && expression.receiver != null) {
irBlock {
+expression.receiver!!.coerceToUnit(context.irBuiltIns, backendContext.typeSystem)
expression.receiver = null
+expression
}
} else {
expression
}
private fun lowerProperty(declaration: IrProperty, kind: ClassKind): List =
ArrayList(4).apply {
val field = declaration.backingField
// JvmFields in a companion object refer to companion's owners and should not be generated within companion.
if ((kind != ClassKind.ANNOTATION_CLASS || field?.isStatic == true) && field?.parent == declaration.parent) {
addIfNotNull(field)
}
if (!declaration.isConst) {
declaration.getter?.takeIf { !shouldSubstituteAccessorWithField(declaration, it) }?.let { add(it) }
declaration.setter?.takeIf { !shouldSubstituteAccessorWithField(declaration, it) }?.let { add(it) }
}
if (!declaration.isFakeOverride && declaration.annotations.isNotEmpty()) {
add(createSyntheticMethodForAnnotations(declaration))
}
}
private fun shouldSubstituteAccessorWithField(property: IrProperty, accessor: IrSimpleFunction?): Boolean =
accessor != null && !property.needsAccessor(accessor)
private fun createSyntheticMethodForAnnotations(declaration: IrProperty): IrSimpleFunction =
backendContext.createSyntheticMethodForProperty(
declaration,
JvmAbi.ANNOTATED_PROPERTY_METHOD_NAME_SUFFIX,
JvmLoweredDeclarationOrigin.SYNTHETIC_METHOD_FOR_PROPERTY_OR_TYPEALIAS_ANNOTATIONS,
// TODO: technically JVM permits having fields with same name but different type, so we could potentially
// generate two properties like that; should this be the getter's return type instead?
isStatic = true, returnType = backendContext.irBuiltIns.unitType, visibility = declaration.visibility
).apply {
body = backendContext.irFactory.createBlockBody(UNDEFINED_OFFSET, UNDEFINED_OFFSET)
annotations = declaration.annotations
}
companion object {
private fun JvmBackendContext.createSyntheticMethodForProperty(
declaration: IrProperty,
suffix: String,
origin: IrDeclarationOrigin,
isStatic: Boolean,
returnType: IrType,
visibility: DescriptorVisibility
) = irFactory.buildFun {
name = Name.identifier(computeSyntheticMethodName(declaration, suffix))
modality = Modality.OPEN
this.origin = origin
this.returnType = returnType
this.visibility = visibility
}.apply {
if (!isStatic) {
dispatchReceiverParameter = declaration.getter?.dispatchReceiverParameter?.let {
// Synthetic methods don't get generic type signatures anyway, so not exactly useful to preserve type parameters.
it.copyTo(this, type = it.type.eraseTypeParameters())
}
}
valueParameters = listOfNotNull(
declaration.getter?.extensionReceiverParameter?.let {
it.copyTo(this, type = it.type.eraseTypeParameters())
}
)
parent = declaration.parent
metadata = declaration.metadata
}
fun JvmBackendContext.createSyntheticMethodForPropertyDelegate(declaration: IrProperty) =
createSyntheticMethodForProperty(
declaration,
JvmAbi.DELEGATED_PROPERTY_NAME_SUFFIX,
IrDeclarationOrigin.PROPERTY_DELEGATE,
isStatic = false, returnType = irBuiltIns.anyNType, visibility = DescriptorVisibilities.PRIVATE
)
private fun JvmBackendContext.computeSyntheticMethodName(property: IrProperty, suffix: String): String {
val baseName =
if (config.languageVersionSettings.supportsFeature(LanguageFeature.UseGetterNameForPropertyAnnotationsMethodOnJvm)) {
val getter = property.getter
if (getter != null) {
val needsMangling =
getter.extensionReceiverParameter?.type?.getRequiresMangling(includeInline = true, includeMFVC = false) == true ||
(config.functionsWithInlineClassReturnTypesMangled && getter.hasMangledReturnType)
val mangled = if (needsMangling) inlineClassReplacements.getReplacementFunction(getter) else null
defaultMethodSignatureMapper.mapFunctionName(mangled ?: getter)
} else JvmAbi.getterName(property.name.asString())
} else {
property.name.asString()
}
return baseName + suffix
}
}
}