org.jetbrains.kotlin.backend.common.lower.AbstractSuspendFunctionsLowering.kt Maven / Gradle / Ivy
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/*
* Copyright 2010-2019 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.common.lower
import org.jetbrains.kotlin.backend.common.*
import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
import org.jetbrains.kotlin.descriptors.Modality
import org.jetbrains.kotlin.ir.IrElement
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.impl.IrInstanceInitializerCallImpl
import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
import org.jetbrains.kotlin.ir.types.*
import org.jetbrains.kotlin.ir.util.*
import org.jetbrains.kotlin.utils.*
import org.jetbrains.kotlin.ir.visitors.*
import org.jetbrains.kotlin.name.Name
abstract class AbstractSuspendFunctionsLowering(val context: C) : FileLoweringPass {
protected companion object {
val STATEMENT_ORIGIN_COROUTINE_IMPL = IrStatementOriginImpl("COROUTINE_IMPL")
val DECLARATION_ORIGIN_COROUTINE_IMPL = IrDeclarationOriginImpl("COROUTINE_IMPL")
}
protected abstract val stateMachineMethodName: Name
protected abstract fun getCoroutineBaseClass(function: IrFunction): IrClassSymbol
protected abstract fun nameForCoroutineClass(function: IrFunction): Name
protected abstract fun buildStateMachine(
stateMachineFunction: IrFunction,
transformingFunction: IrFunction,
argumentToPropertiesMap: Map,
)
protected abstract fun IrBlockBodyBuilder.generateCoroutineStart(invokeSuspendFunction: IrFunction, receiver: IrExpression)
protected abstract fun initializeStateMachine(coroutineConstructors: List, coroutineClassThis: IrValueDeclaration)
protected open fun IrBuilderWithScope.generateDelegatedCall(expectedType: IrType, delegatingCall: IrExpression): IrExpression =
delegatingCall
override fun lower(irFile: IrFile) {
irFile.transformDeclarationsFlat(::tryTransformSuspendFunction)
irFile.acceptVoid(object : IrElementVisitorVoid {
override fun visitElement(element: IrElement) {
element.acceptChildrenVoid(this)
}
override fun visitClass(declaration: IrClass) {
declaration.acceptChildrenVoid(this)
if (declaration.origin != DECLARATION_ORIGIN_COROUTINE_IMPL)
declaration.transformDeclarationsFlat(::tryTransformSuspendFunction)
}
})
}
private fun tryTransformSuspendFunction(element: IrElement): List? {
val function = (element as? IrSimpleFunction) ?: return null
if (!function.isSuspend || function.modality == Modality.ABSTRACT) return null
val (tailSuspendCalls, hasNotTailSuspendCalls) = collectTailSuspendCalls(context, function)
return if (hasNotTailSuspendCalls) {
listOf(buildCoroutine(function).clazz, function)
} else {
// Otherwise, no suspend calls at all or all of them are tail calls - no need in a state machine.
// Have to simplify them though (convert them to proper return statements).
simplifyTailSuspendCalls(function, tailSuspendCalls)
null
}
}
protected fun IrCall.isReturnIfSuspendedCall() =
symbol == context.ir.symbols.returnIfSuspended
private fun simplifyTailSuspendCalls(irFunction: IrSimpleFunction, tailSuspendCalls: Set) {
if (tailSuspendCalls.isEmpty()) return
val irBuilder = context.createIrBuilder(irFunction.symbol)
irFunction.body!!.transformChildrenVoid(object : IrElementTransformerVoid() {
override fun visitCall(expression: IrCall): IrExpression {
val shortCut = if (expression.isReturnIfSuspendedCall())
expression.getValueArgument(0)!!
else expression
shortCut.transformChildrenVoid(this)
return if (!expression.isSuspend || expression !in tailSuspendCalls)
shortCut
else irBuilder.at(expression).irReturn(
irBuilder.generateDelegatedCall(irFunction.returnType, shortCut)
)
}
})
}
private val symbols = context.ir.symbols
private val getContinuationSymbol = symbols.getContinuation
private val continuationClassSymbol = getContinuationSymbol.owner.returnType.classifierOrFail as IrClassSymbol
private fun buildCoroutine(irFunction: IrSimpleFunction) =
CoroutineBuilder(irFunction).build().also { coroutine ->
// Replace original function with a call to constructor of the built coroutine.
val irBuilder = context.createIrBuilder(irFunction.symbol, irFunction.startOffset, irFunction.endOffset)
irFunction.body = irBuilder.irBlockBody(irFunction) {
val constructor = coroutine.constructor
generateCoroutineStart(coroutine.stateMachineFunction,
irCallConstructor(constructor.symbol, irFunction.typeParameters.map {
it.defaultType.makeNullable()
}).apply {
val functionParameters = irFunction.explicitParameters
functionParameters.forEachIndexed { index, argument ->
putValueArgument(index, irGet(argument))
}
putValueArgument(
functionParameters.size,
irCall(
getContinuationSymbol,
getContinuationSymbol.owner.returnType,
listOf(irFunction.returnType)
)
)
})
}
}
private class BuiltCoroutine(val clazz: IrClass, val constructor: IrConstructor, val stateMachineFunction: IrFunction)
private inner class CoroutineBuilder(val irFunction: IrFunction) {
private val functionParameters = irFunction.explicitParameters
private val coroutineClass: IrClass =
context.irFactory.buildClass {
startOffset = irFunction.startOffset
endOffset = irFunction.endOffset
origin = DECLARATION_ORIGIN_COROUTINE_IMPL
name = nameForCoroutineClass(irFunction)
visibility = DescriptorVisibilities.PRIVATE
}.apply {
parent = irFunction.parent
createParameterDeclarations()
typeParameters = irFunction.typeParameters.memoryOptimizedMap { typeParam ->
typeParam.copyToWithoutSuperTypes(this).apply { superTypes = superTypes memoryOptimizedPlus typeParam.superTypes }
}
}
private val coroutineClassThis = coroutineClass.thisReceiver!!
private val continuationType = continuationClassSymbol.typeWith(irFunction.returnType)
// Save all arguments to fields.
private val argumentToPropertiesMap = functionParameters.associateWith { coroutineClass.addField(it.name, it.type, false) }
private val coroutineBaseClass = getCoroutineBaseClass(irFunction)
private val coroutineBaseClassConstructor = coroutineBaseClass.owner.constructors.single { it.valueParameters.size == 1 }
private val coroutineConstructors = mutableListOf()
fun build(): BuiltCoroutine {
coroutineClass.superTypes = mutableListOf(coroutineBaseClass.defaultType)
val coroutineConstructor = buildConstructor()
val superInvokeSuspendFunction = coroutineBaseClass.owner.simpleFunctions().single { it.name == stateMachineMethodName }
val invokeSuspendMethod = buildInvokeSuspendMethod(superInvokeSuspendFunction, coroutineClass)
coroutineClass.addFakeOverrides(context.typeSystem)
initializeStateMachine(coroutineConstructors, coroutineClassThis)
return BuiltCoroutine(coroutineClass, coroutineConstructor, invokeSuspendMethod)
}
fun buildConstructor(): IrConstructor =
context.irFactory.buildConstructor {
startOffset = irFunction.startOffset
endOffset = irFunction.endOffset
origin = DECLARATION_ORIGIN_COROUTINE_IMPL
visibility = irFunction.visibility
returnType = coroutineClass.defaultType
isPrimary = true
}.apply {
parent = coroutineClass
coroutineClass.declarations += this
coroutineConstructors += this
valueParameters = functionParameters.memoryOptimizedMap { parameter ->
parameter.copyTo(this, DECLARATION_ORIGIN_COROUTINE_IMPL)
}
val continuationParameter = coroutineBaseClassConstructor.valueParameters[0]
valueParameters = valueParameters memoryOptimizedPlus continuationParameter.copyTo(
this, DECLARATION_ORIGIN_COROUTINE_IMPL,
type = continuationType
)
val irBuilder = context.createIrBuilder(symbol, startOffset, endOffset)
body = irBuilder.irBlockBody {
val completionParameter = valueParameters.last()
+irDelegatingConstructorCall(coroutineBaseClassConstructor).apply {
putValueArgument(0, irGet(completionParameter))
}
+IrInstanceInitializerCallImpl(startOffset, endOffset, coroutineClass.symbol, context.irBuiltIns.unitType)
functionParameters.forEachIndexed { index, parameter ->
+irSetField(
irGet(coroutineClassThis),
argumentToPropertiesMap.getValue(parameter),
irGet(valueParameters[index])
)
}
}
}
private fun buildInvokeSuspendMethod(
stateMachineFunction: IrSimpleFunction,
coroutineClass: IrClass
): IrSimpleFunction {
val function = context.irFactory.buildFun {
startOffset = irFunction.startOffset
endOffset = irFunction.endOffset
origin = DECLARATION_ORIGIN_COROUTINE_IMPL
name = stateMachineFunction.name
visibility = stateMachineFunction.visibility
returnType = context.irBuiltIns.anyNType
isInline = stateMachineFunction.isInline
isExternal = stateMachineFunction.isExternal
isTailrec = stateMachineFunction.isTailrec
isSuspend = stateMachineFunction.isSuspend
isOperator = false
isExpect = stateMachineFunction.isExpect
isFakeOverride = false
}.apply {
parent = coroutineClass
coroutineClass.declarations += this
typeParameters = stateMachineFunction.typeParameters.memoryOptimizedMap { parameter ->
parameter.copyToWithoutSuperTypes(this, origin = DECLARATION_ORIGIN_COROUTINE_IMPL)
.apply { superTypes = superTypes memoryOptimizedPlus parameter.superTypes }
}
valueParameters = stateMachineFunction.valueParameters.memoryOptimizedMap { parameter ->
parameter.copyTo(this, DECLARATION_ORIGIN_COROUTINE_IMPL)
}
this.createDispatchReceiverParameter()
overriddenSymbols = overriddenSymbols memoryOptimizedPlus stateMachineFunction.symbol
}
buildStateMachine(function, irFunction, argumentToPropertiesMap)
return function
}
}
fun IrClass.addField(name: Name, type: IrType, isMutable: Boolean): IrField {
val klass = this
return factory.buildField {
this.startOffset = klass.startOffset
this.endOffset = klass.endOffset
this.origin = DECLARATION_ORIGIN_COROUTINE_IMPL
this.name = name
this.type = type
this.visibility = DescriptorVisibilities.PRIVATE
this.isFinal = !isMutable
}.also {
it.parent = this
addChild(it)
}
}
}