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org.jetbrains.kotlin.backend.common.lower.AbstractSuspendFunctionsLowering.kt Maven / Gradle / Ivy
/*
* 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.backend.common.ir.*
import org.jetbrains.kotlin.descriptors.Modality
import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
import org.jetbrains.kotlin.ir.IrElement
import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
import org.jetbrains.kotlin.ir.builders.*
import org.jetbrains.kotlin.ir.builders.declarations.buildClass
import org.jetbrains.kotlin.ir.builders.declarations.buildConstructor
import org.jetbrains.kotlin.ir.builders.declarations.buildField
import org.jetbrains.kotlin.ir.builders.declarations.buildFun
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.symbols.IrSimpleFunctionSymbol
import org.jetbrains.kotlin.ir.types.IrType
import org.jetbrains.kotlin.ir.types.classifierOrFail
import org.jetbrains.kotlin.ir.types.defaultType
import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeImpl
import org.jetbrains.kotlin.ir.types.typeWith
import org.jetbrains.kotlin.ir.util.*
import org.jetbrains.kotlin.ir.visitors.*
import org.jetbrains.kotlin.name.Name
@ObsoleteDescriptorBasedAPI
abstract class AbstractSuspendFunctionsLowering(val context: C) : FileLoweringPass {
protected object STATEMENT_ORIGIN_COROUTINE_IMPL : IrStatementOriginImpl("COROUTINE_IMPL")
protected object 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
private val builtCoroutines = mutableMapOf()
private val suspendLambdas = mutableMapOf()
override fun lower(irFile: IrFile) {
markSuspendLambdas(irFile)
buildCoroutines(irFile)
transformCallableReferencesToSuspendLambdas(irFile)
}
private fun buildCoroutines(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)
declaration.transformDeclarationsFlat(::tryTransformSuspendFunction)
}
})
}
// Suppress since it is used in native
@Suppress("MemberVisibilityCanBePrivate")
protected fun IrCall.isReturnIfSuspendedCall() =
symbol.owner.run { fqNameWhenAvailable == context.internalPackageFqn.child(Name.identifier("returnIfSuspended")) }
private fun tryTransformSuspendFunction(element: IrElement) =
if (element is IrSimpleFunction && element.isSuspend && element.modality != Modality.ABSTRACT)
transformSuspendFunction(element, suspendLambdas[element])
else null
private fun markSuspendLambdas(irElement: IrElement) {
irElement.acceptChildrenVoid(object : IrElementVisitorVoid {
override fun visitElement(element: IrElement) {
element.acceptChildrenVoid(this)
}
override fun visitFunctionReference(expression: IrFunctionReference) {
expression.acceptChildrenVoid(this)
if (expression.isSuspend) {
suspendLambdas[expression.symbol.owner] = expression
}
}
})
}
private fun transformCallableReferencesToSuspendLambdas(irElement: IrElement) {
irElement.transformChildrenVoid(object : IrElementTransformerVoid() {
override fun visitFunctionReference(expression: IrFunctionReference): IrExpression {
expression.transformChildrenVoid(this)
if (!expression.isSuspend)
return expression
val coroutine = builtCoroutines[expression.symbol.owner]
?: throw Error("Non-local callable reference to suspend lambda: $expression")
val constructorParameters = coroutine.coroutineConstructor.valueParameters
val expressionArguments = expression.getArguments().map { it.second }
assert(constructorParameters.size == expressionArguments.size) {
"Inconsistency between callable reference to suspend lambda and the corresponding coroutine"
}
val irBuilder = context.createIrBuilder(expression.symbol, expression.startOffset, expression.endOffset)
irBuilder.run {
return irCall(coroutine.coroutineConstructor.symbol).apply {
expressionArguments.forEachIndexed { index, argument ->
putValueArgument(index, argument)
}
}
}
}
})
}
private sealed class SuspendFunctionKind {
object NO_SUSPEND_CALLS : SuspendFunctionKind()
class DELEGATING(val delegatingCall: IrCall) : SuspendFunctionKind()
object NEEDS_STATE_MACHINE : SuspendFunctionKind()
}
private fun transformSuspendFunction(irFunction: IrSimpleFunction, functionReference: IrFunctionReference?) =
when (val suspendFunctionKind = getSuspendFunctionKind(irFunction)) {
is SuspendFunctionKind.NO_SUSPEND_CALLS -> {
null // No suspend function calls - just an ordinary function.
}
is SuspendFunctionKind.DELEGATING -> { // Calls another suspend function at the end.
removeReturnIfSuspendedCallAndSimplifyDelegatingCall(irFunction, suspendFunctionKind.delegatingCall)
null // No need in state machine.
}
is SuspendFunctionKind.NEEDS_STATE_MACHINE -> {
val coroutine = buildCoroutine(irFunction, functionReference) // Coroutine implementation.
if (irFunction in suspendLambdas) // Suspend lambdas are called through factory method ,
listOf(coroutine) // thus we can eliminate original body.
else
listOf(coroutine, irFunction)
}
}
private fun getSuspendFunctionKind(irFunction: IrSimpleFunction): SuspendFunctionKind {
if (irFunction in suspendLambdas)
return SuspendFunctionKind.NEEDS_STATE_MACHINE // Suspend lambdas always need coroutine implementation.
val body = irFunction.body ?: return SuspendFunctionKind.NO_SUSPEND_CALLS
var numberOfSuspendCalls = 0
body.acceptVoid(object : IrElementVisitorVoid {
override fun visitElement(element: IrElement) {
element.acceptChildrenVoid(this)
}
override fun visitCall(expression: IrCall) {
expression.acceptChildrenVoid(this)
if (expression.isSuspend)
++numberOfSuspendCalls
}
})
// It is important to optimize the case where there is only one suspend call and it is the last statement
// because we don't need to build a fat coroutine class in that case.
// This happens a lot in practise because of suspend functions with default arguments.
// TODO: use TailRecursionCallsCollector.
val lastCall = when (val lastStatement = (body as IrBlockBody).statements.lastOrNull()) {
is IrCall -> lastStatement
is IrReturn -> {
var value: IrElement = lastStatement
/*
* Check if matches this pattern:
* block/return {
* block/return {
* .. suspendCall()
* }
* }
*/
loop@ while (true) {
value = when {
value is IrBlock && value.statements.size == 1 -> value.statements.first()
value is IrReturn -> value.value
else -> break@loop
}
}
value as? IrCall
}
else -> null
}
val suspendCallAtEnd = lastCall != null && lastCall.isSuspend // Suspend call.
return when {
numberOfSuspendCalls == 0 -> SuspendFunctionKind.NO_SUSPEND_CALLS
numberOfSuspendCalls == 1
&& suspendCallAtEnd -> SuspendFunctionKind.DELEGATING(lastCall!!)
else -> SuspendFunctionKind.NEEDS_STATE_MACHINE
}
}
private val symbols = context.ir.symbols
private val getContinuationSymbol = symbols.getContinuation
private val continuationClassSymbol = getContinuationSymbol.owner.returnType.classifierOrFail as IrClassSymbol
private fun removeReturnIfSuspendedCallAndSimplifyDelegatingCall(irFunction: IrFunction, delegatingCall: IrCall) {
val returnValue =
if (delegatingCall.isReturnIfSuspendedCall())
delegatingCall.getValueArgument(0)!!
else delegatingCall
context.createIrBuilder(irFunction.symbol).run {
val statements = (irFunction.body as IrBlockBody).statements
val lastStatement = statements.last()
assert(lastStatement == delegatingCall || lastStatement is IrReturn) { "Unexpected statement $lastStatement" }
statements[statements.lastIndex] = irReturn(generateDelegatedCall(irFunction.returnType, returnValue))
}
}
private fun buildCoroutine(irFunction: IrSimpleFunction, functionReference: IrFunctionReference?): IrClass {
val coroutine = CoroutineBuilder(irFunction, functionReference).build()
builtCoroutines[irFunction] = coroutine
if (functionReference == null) {
// It is not a lambda - 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.coroutineConstructor
generateCoroutineStart(coroutine.stateMachineFunction,
irCallConstructor(constructor.symbol, irFunction.typeParameters.map {
IrSimpleTypeImpl(it.symbol, true, emptyList(), emptyList())
}).apply {
val functionParameters = irFunction.explicitParameters
functionParameters.forEachIndexed { index, argument ->
putValueArgument(index, irGet(argument))
}
putValueArgument(
functionParameters.size,
irCall(
getContinuationSymbol,
getContinuationSymbol.owner.returnType,
listOf(irFunction.returnType)
)
)
})
}
}
return coroutine.coroutineClass
}
private class BuiltCoroutine(
val coroutineClass: IrClass,
val coroutineConstructor: IrConstructor,
val stateMachineFunction: IrFunction
)
private inner class CoroutineBuilder(val irFunction: IrFunction, val functionReference: IrFunctionReference?) {
private val functionParameters = irFunction.explicitParameters
private val boundFunctionParameters = functionReference?.getArgumentsWithIr()?.map { it.first }
private val unboundFunctionParameters = boundFunctionParameters?.let { functionParameters - it }
private val coroutineClass: IrClass =
context.irFactory.buildClass {
startOffset = irFunction.startOffset
endOffset = irFunction.endOffset
origin = DECLARATION_ORIGIN_COROUTINE_IMPL
name = nameForCoroutineClass(irFunction)
visibility = irFunction.visibility
}.apply {
parent = irFunction.parent
createParameterDeclarations()
typeParameters = irFunction.typeParameters.map { typeParam ->
typeParam.copyToWithoutSuperTypes(this).apply { superTypes += 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 create1Function = coroutineBaseClass.owner.simpleFunctions()
.single { it.name.asString() == "create" && it.valueParameters.size == 1 }
private val create1CompletionParameter = create1Function.valueParameters[0]
private val coroutineConstructors = mutableListOf()
fun build(): BuiltCoroutine {
val superTypes = mutableListOf(coroutineBaseClass.defaultType)
var suspendFunctionClass: IrClass? = null
var functionClass: IrClass? = null
val suspendFunctionClassTypeArguments: List?
val functionClassTypeArguments: List?
if (unboundFunctionParameters != null) {
// Suspend lambda inherits SuspendFunction.
val numberOfParameters = unboundFunctionParameters.size
suspendFunctionClass = symbols.suspendFunctionN(numberOfParameters).owner
val unboundParameterTypes = unboundFunctionParameters.map { it.type }
suspendFunctionClassTypeArguments = unboundParameterTypes + irFunction.returnType
superTypes += suspendFunctionClass.typeWith(suspendFunctionClassTypeArguments)
functionClass = symbols.functionN(numberOfParameters + 1).owner
functionClassTypeArguments = unboundParameterTypes + continuationType + context.irBuiltIns.anyNType
superTypes += functionClass.typeWith(functionClassTypeArguments)
}
val coroutineConstructor = buildConstructor()
val superInvokeSuspendFunction = coroutineBaseClass.owner.simpleFunctions().single { it.name == stateMachineMethodName }
val invokeSuspendMethod = buildInvokeSuspendMethod(superInvokeSuspendFunction, coroutineClass)
var coroutineFactoryConstructor: IrConstructor? = null
val createMethod: IrSimpleFunction?
if (functionReference != null) {
// Suspend lambda - create factory methods.
coroutineFactoryConstructor = buildFactoryConstructor(boundFunctionParameters!!)
val createFunctionSymbol = coroutineBaseClass.owner.simpleFunctions()
.atMostOne { it.name.asString() == "create" && it.valueParameters.size == unboundFunctionParameters!!.size + 1 }
?.symbol
createMethod = buildCreateMethod(
unboundArgs = unboundFunctionParameters!!,
superFunctionSymbol = createFunctionSymbol,
coroutineConstructor = coroutineConstructor
)
val invokeFunctionSymbol =
functionClass!!.simpleFunctions().single { it.name.asString() == "invoke" }.symbol
val suspendInvokeFunctionSymbol =
suspendFunctionClass!!.simpleFunctions().single { it.name.asString() == "invoke" }.symbol
buildInvokeMethod(
suspendFunctionInvokeFunctionSymbol = suspendInvokeFunctionSymbol,
functionInvokeFunctionSymbol = invokeFunctionSymbol,
createFunction = createMethod,
stateMachineFunction = invokeSuspendMethod
)
}
coroutineClass.superTypes += superTypes
coroutineClass.addFakeOverridesViaIncorrectHeuristic()
initializeStateMachine(coroutineConstructors, coroutineClassThis)
return BuiltCoroutine(
coroutineClass = coroutineClass,
coroutineConstructor = coroutineFactoryConstructor ?: coroutineConstructor,
stateMachineFunction = 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.mapIndexed { index, parameter ->
parameter.copyTo(this, DECLARATION_ORIGIN_COROUTINE_IMPL, index)
}
val continuationParameter = coroutineBaseClassConstructor.valueParameters[0]
valueParameters += continuationParameter.copyTo(
this, DECLARATION_ORIGIN_COROUTINE_IMPL,
index = valueParameters.size, 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 buildFactoryConstructor(boundParams: List): IrConstructor =
context.irFactory.buildConstructor {
startOffset = irFunction.startOffset
endOffset = irFunction.endOffset
origin = DECLARATION_ORIGIN_COROUTINE_IMPL
visibility = irFunction.visibility
returnType = coroutineClass.defaultType
}.apply {
parent = coroutineClass
coroutineClass.declarations += this
coroutineConstructors += this
valueParameters = boundParams.mapIndexed { index, parameter ->
parameter.copyTo(this, DECLARATION_ORIGIN_COROUTINE_IMPL, index)
}
val irBuilder = context.createIrBuilder(symbol, startOffset, endOffset)
body = irBuilder.irBlockBody {
+irDelegatingConstructorCall(coroutineBaseClassConstructor).apply {
putValueArgument(0, irNull()) // Completion.
}
+IrInstanceInitializerCallImpl(
startOffset, endOffset, coroutineClass.symbol,
context.irBuiltIns.unitType
)
// Save all arguments to fields.
boundParams.forEachIndexed { index, parameter ->
+irSetField(
irGet(coroutineClassThis), argumentToPropertiesMap.getValue(parameter),
irGet(valueParameters[index])
)
}
}
}
private fun buildCreateMethod(
unboundArgs: List,
superFunctionSymbol: IrSimpleFunctionSymbol?,
coroutineConstructor: IrConstructor
): IrSimpleFunction = context.irFactory.buildFun {
startOffset = irFunction.startOffset
endOffset = irFunction.endOffset
origin = DECLARATION_ORIGIN_COROUTINE_IMPL
name = Name.identifier("create")
visibility = DescriptorVisibilities.PROTECTED
returnType = coroutineClass.defaultType
}.apply {
parent = coroutineClass
coroutineClass.declarations += this
typeParameters = irFunction.typeParameters.map { parameter ->
parameter.copyToWithoutSuperTypes(this, origin = DECLARATION_ORIGIN_COROUTINE_IMPL)
.apply { superTypes += parameter.superTypes }
}
valueParameters = (unboundArgs + create1CompletionParameter).mapIndexed { index, parameter ->
parameter.copyTo(this, DECLARATION_ORIGIN_COROUTINE_IMPL, index)
}
this.createDispatchReceiverParameter()
superFunctionSymbol?.let {
overriddenSymbols += it.owner.overriddenSymbols
overriddenSymbols += it
}
val thisReceiver = this.dispatchReceiverParameter!!
val irBuilder = context.createIrBuilder(symbol, startOffset, endOffset)
body = irBuilder.irBlockBody(startOffset, endOffset) {
+irReturn(
irCall(coroutineConstructor).apply {
var unboundIndex = 0
val unboundArgsSet = unboundArgs.toSet()
functionParameters.map {
if (unboundArgsSet.contains(it))
irGet(valueParameters[unboundIndex++])
else
irGetField(irGet(thisReceiver), argumentToPropertiesMap.getValue(it))
}.forEachIndexed { index, argument ->
putValueArgument(index, argument)
}
putValueArgument(functionParameters.size, irGet(valueParameters[unboundIndex]))
assert(unboundIndex == valueParameters.size - 1) {
"Not all arguments of are used"
}
})
}
}
private fun buildInvokeMethod(
suspendFunctionInvokeFunctionSymbol: IrSimpleFunctionSymbol,
functionInvokeFunctionSymbol: IrSimpleFunctionSymbol,
createFunction: IrFunction,
stateMachineFunction: IrFunction
): IrSimpleFunction = context.irFactory.buildFun {
startOffset = irFunction.startOffset
endOffset = irFunction.endOffset
origin = DECLARATION_ORIGIN_COROUTINE_IMPL
name = Name.identifier("invoke")
visibility = DescriptorVisibilities.PROTECTED
returnType = context.irBuiltIns.anyNType
isSuspend = true
}.apply {
parent = coroutineClass
coroutineClass.declarations += this
typeParameters = irFunction.typeParameters.map { parameter ->
parameter.copyToWithoutSuperTypes(this, origin = DECLARATION_ORIGIN_COROUTINE_IMPL)
.apply { superTypes += parameter.superTypes }
}
valueParameters = createFunction.valueParameters
// Skip completion - invoke() already has it implicitly as a suspend function.
.take(createFunction.valueParameters.size - 1)
.mapIndexed { index, parameter ->
parameter.copyTo(this, DECLARATION_ORIGIN_COROUTINE_IMPL, index)
}
this.createDispatchReceiverParameter()
overriddenSymbols += functionInvokeFunctionSymbol
overriddenSymbols += suspendFunctionInvokeFunctionSymbol
val thisReceiver = dispatchReceiverParameter!!
val irBuilder = context.createIrBuilder(symbol, startOffset, endOffset)
body = irBuilder.irBlockBody(startOffset, endOffset) {
generateCoroutineStart(stateMachineFunction, irCall(createFunction).apply {
dispatchReceiver = irGet(thisReceiver)
valueParameters.forEachIndexed { index, parameter ->
putValueArgument(index, irGet(parameter))
}
putValueArgument(
valueParameters.size,
irCall(getContinuationSymbol, getContinuationSymbol.owner.returnType, listOf(returnType))
)
})
}
}
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.map { parameter ->
parameter.copyToWithoutSuperTypes(this, origin = DECLARATION_ORIGIN_COROUTINE_IMPL)
.apply { superTypes += parameter.superTypes }
}
valueParameters = stateMachineFunction.valueParameters.mapIndexed { index, parameter ->
parameter.copyTo(this, DECLARATION_ORIGIN_COROUTINE_IMPL, index)
}
this.createDispatchReceiverParameter()
overriddenSymbols += stateMachineFunction.symbol
}
buildStateMachine(function, irFunction, argumentToPropertiesMap)
return function
}
}
protected open class VariablesScopeTracker : IrElementVisitorVoid {
protected val scopeStack = mutableListOf>(mutableSetOf())
override fun visitElement(element: IrElement) {
element.acceptChildrenVoid(this)
}
override fun visitContainerExpression(expression: IrContainerExpression) {
if (!expression.isTransparentScope)
scopeStack.push(mutableSetOf())
super.visitContainerExpression(expression)
if (!expression.isTransparentScope)
scopeStack.pop()
}
override fun visitCatch(aCatch: IrCatch) {
scopeStack.push(mutableSetOf())
super.visitCatch(aCatch)
scopeStack.pop()
}
override fun visitVariable(declaration: IrVariable) {
super.visitVariable(declaration)
scopeStack.peek()!!.add(declaration)
}
}
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)
}
}
}