azalea/kotlin-fork
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Add more comments to PropertyReferenceLowering

Browse Source
This commit is contained in:
pyos
2019-03-19 11:25:23 +01:00
committed by max-kammerer
parent ed298c48b7
commit 39adfcced1
1 changed files with 43 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files
compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/PropertyReferenceLowering.kt
+43 -20
View File
@@ -36,6 +36,10 @@ internal val propertyReferencePhase = makeIrFilePhase(
)
internal class PropertyReferenceLowering(val context: JvmBackendContext) : ClassLoweringPass {
// Reflection metadata for local properties is serialized under the signature "<v#$N>" attached to the containing class.
// This maps properties to values of N.
private val localPropertyIndices = mutableMapOf<IrSymbol, Int>()
// TODO: join IrLocalDelegatedPropertyReference and IrPropertyReference via the class hierarchy?
private val IrMemberAccessExpression.getter: IrFunctionSymbol?
get() = (this as? IrPropertyReference)?.getter ?: (this as? IrLocalDelegatedPropertyReference)?.getter
@@ -46,14 +50,11 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
private val IrMemberAccessExpression.field: IrFieldSymbol?
get() = (this as? IrPropertyReference)?.field
// Reflection metadata for local properties is serialized under the signature "<v#$N>" attached to the containing class.
// This maps properties to values of N.
private val localPropertyIndices = mutableMapOf<IrSymbol, Int>()
private val IrMemberAccessExpression.signature: String
get() = localPropertyIndices[getter]?.let { "<v#$it>" }
?: getter?.owner?.let { context.state.typeMapper.mapSignatureSkipGeneric(it.descriptor).toString() }
// Plain Java fields do not have a getter, but can be referenced nonetheless.
// Plain Java fields do not have a getter, but can be referenced nonetheless. The signature should be
// the one that a getter would have, if it existed.
?: TODO("plain Java field signature")
private val IrMemberAccessExpression.symbol: IrSymbol
@@ -88,7 +89,7 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
get() {
var current: IrDeclaration? = getter?.owner ?: field?.owner
while (current?.parent is IrFunction)
current = current.parent as IrFunction
current = current.parent as IrFunction // Local delegated property.
return current
}
@@ -98,18 +99,25 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
startOffset, endOffset,
plainJavaClass.defaultType,
plainJavaClass.symbol,
// TODO: when the parent is an interface, this should map to DefaultImpls. However, that requires
// moving this lowering below InterfaceLowering; see another TODO above.
CrIrType(context.state.typeMapper.mapImplementationOwner(propertyContainerChild!!.descriptor))
)
private fun IrBuilderWithScope.buildReflectedContainerReference(expression: IrMemberAccessExpression): IrExpression {
return when (expression.propertyContainerChild?.parent) {
is IrPackageFragment -> irCall(getOrCreateKotlinPackage).apply {
putValueArgument(0, expression.parentJavaClassReference)
putValueArgument(1, irString(this@PropertyReferenceLowering.context.state.moduleName))
}
is IrClass -> irCall(getOrCreateKotlinClass).apply {
putValueArgument(0, expression.parentJavaClassReference)
}
val parent = expression.propertyContainerChild?.parent
return when {
// FileClassLowering creates a class to which all package-level declarations are moved. However, it does not
// fix the declarations' parents (yet), which is why we check for both a file class and a package fragment.
parent is IrPackageFragment || (parent is IrClass && parent.origin == IrDeclarationOrigin.FILE_CLASS) ->
irCall(getOrCreateKotlinPackage).apply {
putValueArgument(0, expression.parentJavaClassReference)
putValueArgument(1, irString(this@PropertyReferenceLowering.context.state.moduleName))
}
parent is IrClass ->
irCall(getOrCreateKotlinClass).apply {
putValueArgument(0, expression.parentJavaClassReference)
}
else -> throw AssertionError("referenced property not inside a class/package fragment")
}
}
@@ -152,18 +160,19 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
origin = JvmLoweredDeclarationOrigin.GENERATED_PROPERTY_REFERENCE
isFinal = true
isStatic = true
// TODO: make the visibility package-local. Currently it's more permissive to allow access from inline functions.
}
var localPropertiesInClass = 0
irClass.transformChildrenVoid(object : IrElementTransformerVoidWithContext() {
override fun visitPropertyReference(expression: IrPropertyReference): IrExpression =
cachedKProperty(expression)
override fun visitLocalDelegatedProperty(declaration: IrLocalDelegatedProperty): IrStatement {
localPropertyIndices[declaration.getter.symbol] = localPropertiesInClass++
return super.visitLocalDelegatedProperty(declaration)
}
override fun visitPropertyReference(expression: IrPropertyReference): IrExpression =
cachedKProperty(expression)
override fun visitLocalDelegatedPropertyReference(expression: IrLocalDelegatedPropertyReference): IrExpression =
cachedKProperty(expression)
@@ -192,6 +201,7 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
// Create an instance of KProperty that uses Java reflection to locate the getter and the setter. This kind of reference
// does not support local variables or bound receivers (e.g. `Class()::field`) and is slower, but takes up less space.
// Example: `C::property` -> `Reflection.property1(PropertyReference1Impl(C::class, "property", "getProperty()LType;"))`.
private fun createReflectedKProperty(expression: IrMemberAccessExpression): IrExpression {
val referenceKind = propertyReferenceKindFor(expression)
return context.createIrBuilder(currentScope!!.scope.scopeOwnerSymbol, expression.startOffset, expression.endOffset).run {
@@ -205,8 +215,20 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
}
}
// Create an instance of KProperty that overrides the get() and set() method to directly call getX() and setX() on the object.
// This is (relatively) fast, but space-inefficient. Also, the instances can store bound receivers in their fields.
// Create an instance of KProperty that overrides the get() and set() methods to directly call getX() and setX() on the object.
// This is (relatively) fast, but space-inefficient. Also, the instances can store bound receivers in their fields. Example:
//
// class C$property$0 : PropertyReference0 {
// constructor(boundReceiver: C) : super(boundReceiver)
// override val name = "property"
// override fun getOwner() = C::class
// override fun getSignature() = "getProperty()LType;"
// override fun get(): T = receiver.property
// override fun set(value: T) { receiver.property = value }
// }
//
// and then `C()::property` -> `C$property$0(C())`.
//
private fun createSpecializedKProperty(expression: IrMemberAccessExpression): IrExpression {
val bound = expression.dispatchReceiver != null || expression.extensionReceiver != null
val referenceClass = kPropertyClasses.getOrPut(PropertyClassCacheKey(expression.symbol, bound)) {
@@ -335,7 +357,8 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
}
})
// Put new field at the beginning so that static delegated properties with initializers work correctly.
// Put the new field at the beginning so that static delegated properties with initializers work correctly.
// Since we do not cache property references with bound receivers, the new field does not reference anything else.
if (kProperties.isNotEmpty()) {
irClass.declarations.add(0, kPropertiesField.apply {
parent = irClass